Solar Power Satellites

August 1981

NTIS order #PB82-108846
Library of Congress Catalog Card Number 81-600129

For sale by the Superintendent of Documents,

U.S. Government Printing Office, Washington, D.C. 20402
Foreword

The energy difficulties the Nation has faced over the past decade have given

rise to an increased awareness of the potential long-term, inexhaustible, or

renewable energy technologies. This assessment responds to a request by the House

Committee on Science and Technology for an evaluation of the energy potential of

one of the most ambitious and long-term of these technologies, the solar power

satellite (SPS).

In assessing SPS, OTA has taken into account the preliminary nature of SPS

technology by comparing four alternative SPS systems across a broad range of

issues: their technical characteristics, long-term energy supply potential, international and military implications, environmental impacts, and institutional effects.

The SPS options are also compared to potentially competitive future energy

technologies in order to identify how choices among them might be made. In addition, OTA developed a set of Federal research and funding options to address the

central questions and uncertainties identified in the report.

We were greatly aided by the advice of the SPS advisory panel, as well as by the

participants in three specialized workshops: one on alternative SPS systems, one on

public opinion, and another on competing energy supply technologies. The contributions of a number of contractors, who provided important analyses, and of

numerous individuals who gave generously of their time and knowledge, are

gratefully appreciated.

Director

. . .

Ill
Solar Power Satellites Advisory Panel

Paul Craig

University of California

S. David Freeman

Tennessee Valley Authority

Eilene Galloway

Consultant

Karl Gawell

Solar Energy Research Institute

Peter G laser

Arthur D. Little, Inc.

John W. Freeman, Jr., Chairman

Rice University

Kenneth Billman

Electric Power Research Institute

Hubert P. Davis

Eagle Engineering

Henry M. Foley

Colurnbia University

Ken Bossong

Citizens Energy Project

Ben Bova

OMNI

Clifflyn Bromling

Bromling and Associates

Mike Casper

Carlton College

Earl Cook

Texas A&M

John P. Schaefer, Chairman

University of Arizona

Jerry Grey

American Institute of Aeronautics

and Astronautics

Grant Hansen

SDC Corp.

Russell Hensley

Aetna Life & Casualty

Maureen Lamb

Consultant

J. C. Randolph

University of Indiana

Workshop on Technical Options

John J. Sheehan

United Steelworkers of America

Graham SiegeI

Tennessee Valley Authority

Robert Uhrig

Florida Power & Light

Frank von Hippel

Princeton University

Charles Warren

Attorney

Joe G. Foreman John D. G. Rather

Naval Research Laboratories The B.D.M. Corp.

Jerry Grey Fred Sterzer

American Institute of Aeronautics RCA Laboratories

and Astronautics Frank von Hippel

Abraham Hertz berg Princeton University

University of Washington Gordon Woodcock

Boeing Aerospace Co

Workshop on SPS Public Opinion Issues

Leonard David

National Space Institute

Chris E If ring

Office of Technology Assessment

Joe Foreman

Naval Research Laboratories

Jerry Grey

American Institute of Aeronautics

and Astronautics

Skip Laitner

Community Action Research Croup

of Iowa, Inc.

Maureen Lamb

Consultant

Jenifer Robinson

Office of Technology Assessment

Louis Slesin

Natural Resources Defense

Council, Inc.

Workshop on Energy Context of Solar Power Satellites

Clark Bullard, Chairman

University of Illinois

Charles Baker

Argonne National Laboratory

Piet Bos

Electric Power Research Institute

Glen Brandvold

Sandia National Laboratory

Clifflyn Bromling

Bromling & Associates

Paul Craig

University of California

Peter Drummond

McDonnel-Douglas Astronautics

Lessly Goudarzi

International Energy Associates,

Limited

Kenneth Hub

Argonne National Laboratory

Jerry Karaganis

Edison Electric Institute

John Lamarsh

Polytechnic Institute of New York

Kenneth Ling

Applied Solar Energy Corp.

William Metz

Consultant

David Morris

Institute for Local Self Reliance

James Moyer

Southern California Edison

Larry Ruff

Brook haven National Laboratory

Frank von Hippel

Princeton University

Gordon Woodcock

Boeing Aerospace Co.

iv
Solar Power Satellites Project Staff

Lionel S. Johns, Assistant Director, OTA

Energy, Materials, and International Security Division

Richard E. Rowberg, Energy Program Manager

David Claridge, Project Director (until January 1980)

Ray A. Williamson, Project Director (from January 1980)

Stefi Weisburd Adam Wasserman

Administrative Staff

Marian Grochowski Lisa Jacobson Lillian Quigg

Edna Saunders Yvonne White

Contributors

Clifflyn Bromling Alan Crane

Arlene Maclin William Metz

Contractors and Consultants

Eric Drexler International Energy Associates, Ltd.

John Furber David Morris

Mark Gersovitz Institute for Local Self Reliance

Princeton University Barry Smernoff

Jerry Grey Smernoff & Associates

OTA Publishing Staff

John C. Holmes, Publishing Officer

John Bergling Kathie S. Boss Debra M. Datcher Joe Henson
Acknowledgments

OTA thanks the following people who took time to provide information or to review part or all of the

study.

Martin Abromavage, Argonne National Laboratory

Edwin Beatrice, Letterman Army Institute of

Research

Richard Beverly and William Brown, Raytheon

Tom Bull, Office of Technology Assessment

Daniel F. Cahill, U.S. Environmental Protection

Agency

Don Calahan, National Aeronautics and Space

Administration

Stephen Cheston, Georgetown University

Stephen Cleary, Mfedical College of Virginia

P. Czerski, National Research Institute of Mother

and Child, Poland

Steven Doyle, Office of Technology Assessment

Lewis Duncan, Los Alamos Scientific Laboratory

William Erickson, University of Mary/and

Harold A. Feiveson, Woodrow Wilson School,

Princeton University

Zorach Glaser, Bureau of Radiological Health

Anita Harlan, L-5 Society

John Hooper, Sierra Club

Wayne Jones, Lockheed Corp.

Don Justesen, Veterans Administration

Fred Koomanoff, U.S. Department of Energy

John Logsdon, George Washington University

Simon V. Manson, National Aeronautics and

Space Administration

Richard Marsten, Office of Technology

Assessment

Ernest L. Morrison, National Telecommunications

and Information Administration

Fred Osborne, Sunsat Energy Council

Steven Plotkin, Office of Technology Assessment

John Richardson, National Academy of Sciences

Michael Riches, U.S. Department of Energy

Donald Rote, Argonne National Laboratory

Charles Rush, National Telecommunications and

Information Administration

Richard Santopietro, U.S. Department of Energy

Carl Schwenk, National Aeronautics and Space

Administration

Richard Setlow, Brookhaven National Laboratory

Charlotte Silverman, U.S. Public Health Service

David Sliney, U.S. Army Environment/ Hygiene

Agency

Marcia Smith, Congressional/ Research Service

Gerald Stokes, Pacific Northwest Laboratory

A.R. Thompson, National Radio Astronomy

Observatory

Kosta Tsipas, Massachusetts Institute’ of

Technology

Paul Tyler, Armed Forces Radiological Research

Institute

A.R. Valentine, Argonne National Laboratory

Peter Vajk, Science Applications, Inc.

Margaret White, Lawrence Berkeley Laboratory

John Zinn, Los Alamos Scientific Laboratory
Contents

Chapter

1.

2.

3.

4.

5.

6.

7.

8.

9.

Summary. . . . . . . . . . . . . . . . .

Introduction . . . . . . . . . . . .

Issues and Find

Policy Options.

Alternative Systems 

ngs . . . . . . .

. . . . . . . . . . . .

 for SPS . .

SPS inContext. . . . . . . . . . . .

The International Implications

Environment and Health. . . . .

Institutional Issues . . . . . . . . .

Page

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

of Solar Power Satellites . . . . . . . . . . . . . . . 145

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

A.

B.

c.

D.

E.

Alternatives to the Reference System Subsystems . . . . . . . . . . . . , . . . . . . . . . . 265

Decentralized Photo voltaic Model . . . . . . . . . . . . . . . . . . . . . ................269

Global Energy Demand Forecasts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ...271

Environment and Health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......275

Examples of international Cooperation . . . . . . . . . . . . . . . . . . . . . . . . .........289

Acronyms, Abbreviations, and Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ....293
Chapter 1
Contents

Page

Current Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Energy Context . . . . . . . . . . . .

International and Military Imp

Systems and Costs. . . . . . . . . .

Public Issues. . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

ications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Environment and Health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Space Context. . . . . . . . . . . . . . . .

LIST

Characterization of Four Alternative SPS

Summaryof SPS Environmental Impacts

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

OF TABLES

Page

Systems. . . . . . . . . . . . . . . . . . . . . . . . . . 9

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
The solar power satellite (SPS) concepts en- ● Mirror transmission. Orbiting mirrors

vision using the constant availability of sun- would reflect sunlight directly to central

light in space to generate baseload electricity locations on Earth. Terrestrial solar reon Earth. Orbiting satellites would collect ceivers would convert the resulting 24-

solar energy and beam it to Earth where it hour illumination to electricity.

would be converted to electricity. Three major Since SPS would be a major future energy alternative systems have been suggested. system with diverse potential impacts and im-

● Microwave transmission. Solar radiation

would be collected in space and converted to microwaves. Microwave energy

would be beamed to a receiving antenna

on Earth where it would be converted to

electricity.

Laser transmission. Solar radiation would

be collected in space and converted to infrared laser radiation. The lasers would

beam power to an Earth receiver.

placations, this assessment of SPS technology

is interdisciplinary. It includes the study of SPS

interactions with society, the environment, the

economy, and other energy systems. in addition, because space is an international realm

and energy is a global need, this assessment

also undertakes a broad look at the international aspects of SPS.

CURRENT STATUS

Too little is currently known about the technical, economic, and environmental aspects of SPS

to make a sound decision whether to proceed

with its development and deployment. I n addition, without further research an SPS demonstration or systems-engineering verification

program would be a high-risk venture. An SPS

research program could ultimately assure an adequate information base for these decisions. However, the urgency of any proposed research effort depends strongly on the perception of future electricity demand, the variety and cost of

supply, and the estimated speed with which

the major technical and environmental uncertainties associated with the SPS concept can

be resolved. For instance, if future demand

growth is expected to be low it may not be necessary to initiate a specific SPS research program at this time, especially if more conventional electric-generating technologies remain

acceptable. If this is not the case or if demand

growth is expected to be high, SPS might be

needed early in the 21st century, and a timely

start of a research effort would be justified.

Should it be decided not to start a dedicated

SPS research effort now, it may be desirable to

designate an agency to track generic research

which is applicable to SPS, to review trends in

electricity demand, and to monitor the progress of other electric supply technologies. Such

a mechanism could provide the basis for periodic assessment of whether to begin an SPS research program. Information relevant to SPS

could be derived from other research programs, microwave bioeffects, space transportation, laser, and photovoltaic development

appear to be the most critical technical issues.

However, it is unlikely that such “generic”

research programs by themselves would adequately answer all of the high-priority questions on which SPS development decisions depend

If a dedicated SPS research effort is started

now, the level of effort chosen would, to a

large degree, determine the time it takes to obtain the information needed for a development

decision. An effort set at $5 million to $10

milIion per year could be sufficient to gather

the minimum necessary information while minimizing the risk of insufficient or untimely information. A $20 million to $30 million per

year effort could gain the maximum necessary

3
4 ● Solar Power Satellites

Photo credit: National Aeronautics and Space Administration

Microwave concept

Photo credit: National Aeronaut/es and Space Administration

Mirrored concept

SOURCE: K. W. Billman, “Space Orbiting Light Augmentation Reflector Energy

System: A Look at Alternative Systems,” SPS Program Review,

June 1979.

information at the earliest possible time. It

reduces the risk of not generating enough information in time to make an adequate development decision. Whatever the level, if a rePhoto credit: Painting by Frank G. Ellis, Lockheed Missiles and Space Co.

Laser concept

search program is instituted, it should investigate those areas most critical to SPS economic, technical, and environmental feasibility Particular attention should be given to

studying and comparing the various technical

alternatives; but the feasibility of SPS also ultimately depends on its social, political, and institutional viability. Thus, a research program should

continue to explore these aspects of SPS development and deployment as well. The following

are the major stages such a program wouId

have to go through:

SPS Program Steps

Concept feasibility stages Development stages

Basic research Systems engineering

Component testing Demonstration satellite

Concept definition Deployment
Ch. 1—Summary ● 5

ENERGY CONTEXT

Even if it were needed and work began now,

a commercial SPS is unlikely to be available

before 2005-15 because of the many uncertainties and the long Ieadtime needed for testing and

demonstration. Therefore, SPS could not be expected to constitute a significant part of electricity supply before 2015-25. By that time, the

United States will be importing very little

foreign oil. Consequently, SPS cannot reduce our

dependence on imported oil in this century.

However, if efficient electric vehicles or other

electric end-use technologies are developed by

about 2010, electricity from SPS or other

sources could substitute for synthetic liquid

fuels generated from coal or biomass.

Along with other electric generating technologies, SPS has the potential to supply several

hundred gigawatts of baseload electrical

power to the U.S. grid by the mid-21st century.

However, the ultimate need for SPS and its

rate of development wiII depend on the rate of

increase in demand for electricity, and the

ability of other energy supply options to meet

ultimate demand more competitively. SPS

would be needed most if coal and/or conventional nuclear options are constrained and if demand for electricity is high.

An aggressive terrestrial solar and conservation program that could lead to an electricity

demand level of only 8 Quads electric (Qe)* in

2030 (equal to current consumption) would

make the development of SPS and other large

new centralized generating technologies less

urgent in the United States. In any event, coal

could continue to fuel the greatest share of

U.S. electrical needs well into the 21st century,

provided no barriers to its use become evident.

Coal, conventional nuclear, terrestrial solar in

its many forms, and geothermal usage could

*A Quad is equal to 1 quadrillion Btu. It is equivalent to the

energy contained in 500,000 barrels of oil per day for 1 year, and

is also approximately the electric energy produced by a 33,500-

MW generator running without interruption for a year As used in

this report, Quads electric (Qe) of demand refer to the energy

equivalent of electricity at point of use Primary energy input at

the generating source of electricity IS somewhat more than three

times these figures

satisfy the entire domestic electricity requirement for demands totaling 20 Qe (2.5 times

current level) or less in 2030. If demand is

higher than 20 Qe, then presumably one or

more of the following, SPS, breeders, and/or

fusion will be needed. Electricity demand will

be strongly affected by the degree that efficient technologies for using electricity can be

developed. Such technologies can have the effect of lowering the overall cost of electricity

compared to competing energy forms.

If generation from coal on a large scale

proves to be unacceptable, domestic electrical

consumption of 8 Qe or less could still be met

by nuclear, geothermal, and terrestrial solar

(central pIant and onsite) technology. For demands up to about 20 Qe, SPS could compete

with terrestrial solar, breeders, and/or fusion

for a share of the centralized baseload market.

If electricity demand exceeds 20 Qe, it will be

difficult to satisfy that demand without vigorous development of al I renewable or inexhaustible forms of generating capacity. For

these higher demand levels, SPS, breeders, and

fusion could all share in supplying U.S. electricity needs. A 30 Qe (3.8 times current consumption) total demand wouId create a market

potential for up to 6 Qe of SPS-delivered energy (225,000-Mw-installed generating capacity

at 90-percent capacity factor). *

Upper Range of Possible SPS Use* *

Electric demand SPS capacity (CW]

in 2030 (Qe] With coal Without coal

7 5 0 0-30

20.0 0-60 100-200

30.0 100-200 100-200

*Current U.S. generating capacity is about 600,000 MW. Current demand represents about 45 percent of this capacity operating 100 percent of the time,

**Coal is used as the swingfuel for our analysis because it has

the largest resource base of any of the current forms of centralized, electric generating technologies It is expected that conventional nuclear would be available but its smaller resource base

would prevent it from having the large effect on generation-mix

choices that coal does It is assumed that breeders, which would

greatly extend the nuclear fission resource base, would be comparable to SPS and fusion in terms of its rate of market penetration (ie, 5 to 10 GW/yr)
6 ● Solar Power Satellties

SPS is designed to provide baseload electricity. By contrast, except for ocean thermal energy conversion, terrestrial solar electrical generation is intermittent. Because our energy

future will require a mix of baseload and intermittent generating technologies, without storage capability, terrestrial solar would not compete directly with SPS. However, the development of inexpensive storage, if achieved,

could enable terrestrial solar electricity generation in all its forms-wind, solar thermal, and

solar photovoltaics–to assume some share of

baseload capacity.* These technologies are less

complex, have fewer uncertainties, and are

considerably nearer to commercial realization

than SPS. Furthermore, they have the flexibility to be introduced into the electrical grid in

small increments as needed to meet demand

increases on a local scale.

Even if inexpensive storage is not available, onsite generating technologies could compete indirectly with SPS. Total need for baseload

power will decrease if a significant portion of

total electrical demand can be met by a combination of dispersed technologies such as

solar photovoltaics, wind, and biomass at costs

that are competitive with centrally generated

electricity. Low demand for centrally generated electricity would consequently reduce

the need to introduce new, large-scale electrical technologies such as SPS, except as

replacement capacity.

As an energy option for the first half of the 21st

century, the potential electrical output and

uncertainties of SPS are comparable to fusion.

These energy options will proceed along different development paths. Except for a laser

system, the basic SPS technologies have been

proven technically feasible. Research would

be needed to develop low-noise microwave

tubes; high-efficiency, low-mass photovoltaics;

efficient continuous-wave lasers; low-mass

mirrors; and space construction and transportation capabilities. Although the fusion community is confident that fusion is feasible,

“energy breakeven, ” the production of more

energy than is put into the fusion process, has

*The percentage share of baseload capacity which would be

feasible for these technologies to assume would depend on their

geographical location and the time of year (see ch 6)

Photo credit: EPA-Documerica—Gene Daniels

Trojan nuclear powerplant on the Columbia River

near Prescott, Wash., 1972

Photo credit: Texas Power & Light

Martin Lake electric generating plant in east Texas
Ch. l—Summary ● 7

not been achieved. For both SPS and fusion, an

economic generating plant would still have to

be developed and demonstrated.

Both energy options are designed to produce baseload central station power in units

from 500 to 5,000 MW. For both, development

cost is high. For fusion, much of the manufacturing infrastructure for the balance of plant,

i.e., other than the fusion device itself, is in

place. Most of the supportive infrastructure

for SPS, including the industrial plants and the

transportation system, would have to be developed.

INTERNATIONAL AND MILITARY IMPLICATIONS

There could be important economic and political advantages to developing SPS as a multinational rather than a unilateral system. These include cooperation in establishing legal and

regulatory norms, shared risk in financing the

R&D and construction costs, improved prospects for global marketing, and forestalling

fears of economic domination and military

use. Although a multinational effort would

face inevitable organizational and political

difficulties, the strong potential interest of

energy-poor, non-U. S. participants in increased

electrical supplies could help make a multinational venture more feasible than a unilateral

one by the United States. GIobal electricity demand may quadruple by 2030, and will be especially strong in developing countries. Western Europe and Japan wouId be likely partners

for a joint project. Depending on the size and

expense of the system used, a number of the

more rapidly developing but less developed

countries might also be interested in participating at lower levels of involvement.

The Soviet Union is carrying on an aggressive space program that may give them an independent capacity to develop SPS, but little

is known about their long-range space or

energy plans. Real or perceived competition

SYSTEMS

The optimum SPS system has not been identified. A National Aeronautics and Space Administration/Department of Energy (NASA/

DOE) microwave reference system* was devel-

*See chs 3 and 5 for a description of the reference system

with the Soviet Union could spur a U.S. commitment to SPS.

The development of fleets of launch and transfer vehicles (for SPS), as well as facilities for living

and working in space, would enhance this Nation’s military space capabilities. Such equipment would give the possessor a large breakout potential for rapid deployment of personnel and hardware in time of crisis, though for

nonemergency situations the military would

prefer to use vehicles designed specifically for

military purposes. SPS itself could be used for

military purposes, such as electronic warfare or

providing energy to military units, but is technically unsuited to constitute an efficient

weapon. Weapons-use of SPS would be prohibited by current bilateral and multilateral

treaties. The satellite portion of SPS is vulnerable to various methods of attack and interference but the likelihood of its being attacked is

only SIightly greater than for major terrestrial

energy systems. The military effects of SPS will

depend largely on the institutional framework

within which it is developed; international involvement would tend to reduce the potential

for use of SPS by the military sector,

AND COSTS

oped to provide a basis for review and analysis

but was not intended to represent the best

possible system. An optimum system should be

able to deliver power in smaller units (about

1,000 MW or less), use smaller terrestrial

receivers, and cost less to develop than the

reference system. Alternative systems may use
lasers or mirrors to transmit solar energy from

space to Earth. Variants of the reference system or other completely different systems may

offer certain improvements; each will need full

study before choosing a system for development.

Current overall cost estimates for the SPS and

its major components are highly uncertain. The

assessments of up-front costs range from $40

billion to $100 billion. The most detailed estimates have been made by NASA for the reference design. These call for a 22-year investment of $102.4 bilIion (1977 dolIars) (including

transportation and factory investment costs) to

produce the first 5-GW satellite, with each additional satellite costing $11.3 billion. The

costs for most improvements to the reference

design, or for alternative systems, are less certain due to the less developed state of nonreference technology. Preliminary studies indicate that the total reference system costs are

likely to be significantly higher. On the other

hand, alternative systems may well be cheaper

than the reference system. The total costs

estimated by NASA include major elements,

such as space transportation and photovoltaic

cells, whose development is likely to proceed

regardless of SPS; these costs should not be

charged solely to SPS. With the possible exception of fusion, the up-front costs for SPS would

be significantly higher than competing baseIoad electric generating systems. Apportioning

the various investment costs and management
Characterization of Four Alternative SPS Systems

Scale

Satellite size 55 km2

18 km2

5 km2

50 km2

Number of satellites 60 (300 GW total) Not projected Not projected 916 (810 GW total)

Power/satellite 5,000 MW 1,500 MW 500 Mw 135,000 MW

Mass 5 x104 tonnes/satellite; 0.1 kW/kg Less mass than reference/O. 1 kW/kg Less mass than reference/O.05 kW/kg 2 x 105 tonnes mirror system 2 kW/kg

Land use rectenna site 174 km2 (including buffer) 50 km2

0.6 km2

1,000 km2

x 60=10,440 km2

k m

2 1,000 M W 35 33 1.2 7.4

Energy Electricity Electricity Electricity, onsite generation. Electricity, light

Fairly centralized Less centralized Less centralized Highly centralized

23 mW/cm2 Gaussian distribution Unknown Unknown (10 mW/cm2 at edge) 1.15 kW/m2 (1 Sun)

Atmosphere

Transmission Ionosphere heating might affect telecommunications Tropospheric heating might modify weather over smaller area; problems with clouds?

Effluents Possible effects include alteration of magnetosphere (AR+), increased water content; LEO orbit, smaller size, smaller launch vehicles

formation of noctilucent clouds; ionosphere depletion

Electromagnetic

Interference RFI from direct coupling, spurious noise, and harmonics, Impacts on communications,

satellites etc from 245 GHz Problem for radio astronomers (GEO obscures portion of

sky always) optical reflections from satellites and LEO stations WiII change the night sky

Bioeffects Microwave bioeffects midbeam could cause thermal heating, unknown effects of long

term exposure to low-level microwaves Ecosystem alteratlon? Birds avoid/attracted

to beam?

If visible light IS used there may be problems Problem for optical astronomy, optical reflecfor optical astronomy if Infrared IS used may hens and Interference from beam change

Increase airglow optical reflection from LEO night sky in vicinity of sites

satellite.

Direct beam ocular and skin damage ocular Psychological and physiological effects of 24-

damage from reflections? Other effects? Birds hour illumination not known. Possible ocular

flying through will burn up? If visible WiII hazard if viewed with binoculars? Ecosystem

birds avoid? Ecosystem alterations? alteration

National security

weapons potential GEO gives a good vantage point over hemisphere Direct weapon: as ABM, antisatellite, aimed at Indirect: night illumination psychological–

terrestrial targets possible weather modification

–Provides a lot of power m space platform for surveillance, jamming–

Indirect: power killer

satellite, planes space platform

–Requires development of large space fleet with/military potential– Laser defend self, best, LEO more accessible

Vulnerability Satellites may need self defense system to protect against attack Less ground sites; a lot of mirrors-redunSize and distance strong defenses– dancy; individual mirrors fragile; ground sites

still produce power in absence of space

system

International Will require radio frequency allocation and orbit assignment LEO more accessible to U S S R and high-latitude countries, smaller parcels of energy make

Smaller parcels of energy make system more system more flexible

flexible

Meet environmental and health standards?

a

smaller SOLARES systems, e g , IO GW/site would be possible and probably more desirable

b

$l02 billilon–NASA estimate+ncludes Investment Costs

c

Estimates byArgonneNational Laboratory, Office of Technology Assessment, u.s. Congress

SOURCE Office of Technology Assessment.
10 . Solar Power Satellites

responsibilities between the public and private

sectors, and among potential international participants, would be an essential part of SPS development.

PUBLIC ISSUES

Public opinion about SPS is currently not

well-formed. Discussion of SPS has been limited to a small number of public interest

groups and professional societies. In general,

those in favor of SPS also support a vigorous U.S.

space program, whereas many of those who oppose SPS fear that it would drain resources from

small-scale, terrestrial solar technologies. Assuming acceptance of a decision to deploy SPS,

public discussion is likely to be most intense at

the siting stage of its development. Key issues

that may enter into public thinking include

environment and health risks, land-use, military implications, and costs. Centralization in

the decisionmaking process and in the ownership and control of SPS may also be important.

From the standpoint of public perceptions, the

siting of land-based receivers could be an

obstacle to the deployment of SPS unless:

● the public is actively involved in the siting

process;

● health and environment uncertainties are

diminished; and

• local residents are justly compensated for

the use of their land.

Offshore siting of receivers could minimize

potential public resistance to SPS siting.

Reference System —Rectenna/

Washington, D. C., Overlay

SOURCE: Off Ice of Technology Assessment.

ENVIRONMENT AND HEALTH

Many of the environmental impacts associated

with SPS are comparable in nature and magnitude

to those resulting from other large-scale terrestrial energy technologies. A possible exception

is coal, particularly if CO2 concerns are proven

justified. While these effects have not been

quantified adequately, it is thought that conventional corrective measures could be prescribed to minimize their impacts. However,

several health and environmental effects, which

are unique to SPS and whose severity and likelihood are highly uncertain, have also been identified. These include effects on the upper atmosphere from launch effluents and power

transmission, health hazards associated with

non ionizing radiation, electromagnetic interference with other systems and astronomy, and

radiation exposure for space workers. More research in these areas would be required before

decisions about the deployment or development of SPS could be made. Little information is currently available on the environmental impacts of SPS designs other than the

reference system. Clearly, environmental

assessments of the alternative systems will be

needed if choices are to be made between SPS

designs.

Too little is known about the biological effects

of long-term exposure to low-level microwave
Ch. 1—Summary . 11

Photo credit: National Aeronautics and Space Administration

An artist’s concept of an offshore antenna that would receive microwave energy beamed from

a large space solar power collector in geosynchronous orbit

radiation to assess the health risks associated

with SPS microwave systems. The information

that is available is incomplete and not directly

relevant to SPS. Further research is critically

needed in order to set human-health exposure

limits. Currently, no microwave population exposure standard exists in the United States.

The recommended limit for occupational exposure is set at 10 mW/cm2 in the United

States, 1,000 times less stringent than the present U.S.S.R. occupational standard. Public exclusion boundaries around the reference design have been established at one one-hundredth of U.S. occupational guidelines. It is anticipated that future maximum permissible

U.S. occupational standards will be lower by a

factor of 2-Io; population standards, if established, may well be lower than the occupational standards. Even more stringent microwave standards couId increase land requirements and system cost or alter system design

and feasibility. In Iight of the widespread proliferation of electromagnetic devices and the

current controversy surrounding the use of

microwave technologies, it is clear that increased understanding of the effects of microwaves on living things is vitally needed even if

SPS is never deployed.

Exposure of space workers to ionizing radiation

is a potentially serious problem for SPS systems

that operate in geosynchronous orbit (CEO). Recent estimates indicate that the radiation dose

of SPS reference system personnel in CEO

would exceed current limits set for astronauts

and could result in a measurable increase in
12 Ž Solar Power Satellites

Summary of SPS Environmental Impacts

System component Occupational health

characteristics Environmental impact Public health and safety and safety —

Power transmission

Microwave —b

Ionospheric heating could —bEffects of Iow-level —Higher risk than for .

disrupt telecommunications. chronic exposure to micro- public; protective

Maximum tolerable power waves are unknown. clothing required for

density is not known. — Psychological effects of terrestrial worker.

Effects in the upper microwave beam as weapon. —Accidental exposure to

ionosphere are not known —Adverse aesthetic effects high-intensity beam in

—Tropospheric heating could on appearance of night sky. space potentially severe

result in minor weather but no data.

modification.

—bEcosystem: microwave bioeffects (on plants, animals,

and airborne biota) largely

unknown; reflected light

effects unknown.

—b Potential interference with

satellite communications,

terrestrial communications,

radar, radio, and optical

astronomy.

Lasers —Tropospheric heating could —Ocular hazard? —Ocular and safety

modify weather and spread — Psychological effects of hazard?

the beam. laser as weapon are

— Ecosystem: beam may possible.

incinerate birds and —Adverse aesthetic effects

vegetation. on appearance of night

— bPotential interference sky are possible.

with optical astronomy,

some interference with

radio astronomy.

Mirrors —b

Tropospheric heating —Ocular hazard? —Ocular hazard?

could modify weather. —Psychological effect of

—Ecosystem: effect of 24- 24-hr sunlight.

hr light on growing —

b Adverse aesthictic effects

cycles of plants and cir- on appearance of night

cadian rhythms of animals. sky are possible.

—b

potential interference

with optical astronomy.

Transportation and

space operation

Launch and recovery —Ground cloud might pollute

air and water and cause

possible weather modiHLLV fication; acid rain

PLV probably negligible.

COTV —b Water vapor and other

POTV launch effluents could

deplete ionosphere and

enhance airglow. Resultant disruption of communications and satellite

surveillance potentially

important, but uncertain.

—b possible formation of

noctilucent clouds in

stratosphere and mesosphere; effects on climate

are not known.

—Noise (sonic boom) may

exceed EPA guidelines.

–Ground cloud might affect

air quality; acid rain

probably negligible.

—Accidents-catastrophic

explosion near launch

site, vehicle crash, toxic

materials.

—b Space worker’s hazards:

ionizing radiation

(potentially severe)

weightlessness, life

support failure, long

stay in space,

construction accidents

psychological stress,

acceleration.

—Terrestrial worker’s

hazards: noise, transportation accidents.
Ch. 1—Summary ● 13

Summary of SPS Environmental Impacts—Continued

System component Occupational health

characteristics Environmental impact Public health and safety and safety

—bEmission of water vapor

could alter natural

hydrogen cycle; extent and

implications are not wellknown.

—bEffect of COTV argon ions

on magnetosphere and

plasma-sphere could be

great but unknown.

—Depletion of ozone layer

by effluents expected to

be minor but uncertain.

—Noise.

Terrestrial activities

Mining — Land disturbance

(stripmining, etc.).

—Measurable increase of

air and water pollution.

—Solid waste generation

—Strain on production

capacity of gallium

arsenide, sapphire, silicon,

graphite fiber, tungsten,

and mercury.

—

Manufacturing —Measurable increase of

air and water pollution.

—Solid wastes.

—Toxic material exposure. —Occupational air and

—Measurable increase of water pollution.

air and water pollution. —Toxic materials exposure.

— Land-use disturbance. —Noise.

— Measurable increase of —Toxic materials exposure.

air and water pollution. —Noise.

—Solid wastes.

—Exposure to toxic

materials.

Construction —Measurable land — Measurable land —Noise.

disturbance. disturbance. —Measurable local

—Measurable local increase —Measurable local increase increase of air and water

of air and water pollution. of air and water pollution. pollution.

—Accidents.

Receiving antenna —b

Land use and siting— —b

Land use—reduced — Waste heat.

—Waste heat and surface property value, aesthetics,

roughness could modify vulnerability y (less land

weather. for solid-state, laser

options; more for reference

and mirrors).

High-voltage —b

Land use and siting— —b Exposure to high intensity —bExposure to high

transmission lines —bEcosystem: bioeffects of EM fields—effects intensity EM fields—

(not unique to SPS) powerlines uncertain. uncertain. effects uncertain.

a 

impacts based on SPS systems as currently defined and do not account for offshore receivers or possible mitigating system modifications.

bResearch priority.

SOURCE: Office of Technology Assessment.
14 Ž Solar Power Satellites

cancer incidence. However, there are a large

number of uncertainties associated with quantifying the health risks of exposure to ionizing

radiation. More research would be required to

reduce these uncertainties and to identify and

evaluate system designs and shielding techniques that would minimize risks at an acceptable cost. In addition, acceptable SPS radiation limits would have to be determined. If

CEO SPS systems are to be considered, an

assessment of the health risks associated with

space radiation is a top priority.

The potential for interference with other users

of the electromagnetic spectrum could constitute

a severe drawback for the microwave option.

Satellite communications and optical and

radio astronomy would be seriously affected.

The effects on radio and optical astronomy

would be the most difficult to ameliorate. The

minimum allowable spacing between geosynchronous power satellites and geosynchronous

communications satellites is not well-known.

The optical interference effects of either the

mirror or laser transmission options would be

of great concern to ground-based astronomers.

Any of the SPS options would alter the appearance of the nighttime sky. Some may find

this esthetialIy objectionable.

.

SPACE CONTEXT

The hardware, experienced personnel, and industrial infrastructure generated by an SPS project

would significantly increase U.S. space capabilities and, in conjunction with other major

space programs, could lay the groundwork for

the industrialization, mining, and perhaps the

settlement of space. NASA is likely to play a

major role, especialIy in the initial stages of development. Non-SPS programs could be aided

by accelerated development of transportation

and other systems; on the other hand, they

could be harmed by the diversion of funds and

attention to SPS. An SPS research and development program would be in accord with current

space policy that calIs for peaceful development of commercial and scientific space

capab i I i t i es

Given the current absence of long-term program goals for the U.S. civilian space program,

it is difficult to predict the effects of an SPS

project on NASA plans or on private-sector capabilities These effects will need to be carefully considered.
Chapter 2

INTRODUCTION
Chapter 2

INTRODUCTION

As the United States and the world have begun to face the realities of living with a limited

supply of oil and gas, and the political uncertainties that accompany impending scarcity,

the search for reliable, safe means of using the

radiant energy of the Sun has intensified. Solar

radiation is already used in many parts of the

Nation for direct space heating and for heating

water. It can also produce electricity by photovoltaic and thermoelectric conversion. However, nearly all terrestrial solar collectors and

converters suffer from the drawbacks of the

day-night cycle. On Earth, sunlight is only

available during daylight hours, but energy is

consumed around the clock. In the absence of

inexpensive storage, nighttime and cloud cover limit the potential of terrestrial solar technologies (with the exception of ocean thermal

energy conversion) to supply the amounts of

energy required for use in homes, businesses,

and industries. By placing the solar collectors

in space where sunlight is intense and constant, and then “beaming” energy to Earth, the

solar power satellite (SPS) seeks to assure a

baseload supply of electricity for terrestrial

consumers.

Several radically different versions of SPS

have been proposed, most of which will be described and analyzed in this report. In the most

extensively studied version, a large satellite

would be placed in the geosynchronous orbit

so that it remains directly above a fixed point

on the Earth’s Equator. Solar photovoltaic

panels aboard the satellite would collect the

Sun’s radiant energy and convert it to electricity. Devices would then convert the electricity to microwave radiation and transmit it

to Earth where it would be collected, reconverted to electricity, and delivered to the electric power grid. An alternative concept envisions using large orbiting reflectors to reflect

solar radiation to the ground, creating immense solar farms where sunlight would be

available around the clock. Laser beams have

also been proposed for the energy transmission

medium. These concepts may have significantly different economic prospects, as well as different degrees of technical feasibility. In addition, they would affect the environment and

political and financial institutions in different

ways.

The first serious discussion of the SPS concept appeared in 1968. ’ 2 During the next few

years several companies conducted preliminary analyses with some support from the Advanced Programs Off ice of the National Aeronautics and Space Administration (NASA).3

In May 1973, the Subcommittee on Space

Science and Applications of the House Science

and Astronautics Committee heId the first congressional hearings on the concept.4 Following

those hearings, NASA began a series of experiments in microwave transmission of power at

the Jet Propulsion Laboratory. In 1975, NASA

created an SPS study office at the Johnson

Space Center that performed several additional systems studies. A number of papers

were published, s culminating in an extensive

report that established most of the basis for

the Department of Energy’s (DOE) reference

system design. 6

In the beginning it had been assumed that

NASA would be the Federal agency with prime

responsibility for satellite power stations.

However, the Solar Energy Act of 1974 clearly

placed the responsibility for all solar energy

R&D aimed at terrestrial use under the jurisdic1 P E Claser, “The Future of Power From the Sun, ” lntersociety Energy Conversion Engineering Conference (l ECEC), IEEE publication 68C-21 -Energy, 1968, pp. 98-103,

2P E Glaser, “Power From the Sun: Its Future,” Science 162,

NOV 22, 1968, pp. 857-886,

‘P E Claser, O. E, Maynard, J. Mockovciak, and E, L, Ralph,

“Feasibility Study of a Satellite Solar Power Station,” Arthur D.

Little Inc , NASA CR-2357 (contract No. NAS 3-16804), February

1974.

“’Power From the Sun via Satellite, ” hearings before the

Subcommittee on Space Science and Applications and Subcommittee on Energy of the Committee on Science and Astronautics,

U S House of Representatives, May 7, 22, 24,1973.

5Wlll lam J. Richard, “Geosynchronous Satellite Solar Power,”

ch, 8 of So/ar Energy for Earth: An A /AA Assessment, H. J. Kill ian,

G L Dugger, and J. Grey (eds.), AlAA, Apr. 21, 1975, pp. 59-71.

(Also see abridged version in Astronautics and Aeronautics,

November 1975, pp. 46-52.)

“’ln(tlal Technical, Environmental, and Economic Evaluation

of space solar Power Concepts, ” report No. j SC-11568, VOIS. I

and II, NASA, Aug. 31, 1976.

17
18 ● Solar Power Satellites

tion of the Energy Research and Development

Administration (ERDA). ERDA set up a Task

Group on Satellite Power Stations, and in November 1976 recommended two options for

conducting a joint ERDA/NASA 3-year SPS

concept development and evaluation program, one costing $12 million and one $19 million. ’ ERDA elected to pursue a median

course, and proposed a 3-year, $15.5 million effort which began in fiscal year 1977, the SPS

Concept Development and Evaluation Program.

ERDA’s efforts were given impetus by two

congressional hearings, one held in January

1976 by the Subcommittee on Aerospace Technology and National Needs of the Senate

Aeronautical and Space Sciences Committee8

and one held in February 1976 by two subcommittees of the House Committee on Science

and Technology.9

When DOE was created in 1977, it established a special Satellite Power System project

office in the Office of Energy Research to complete the Concept Development and Evaluation Program. Its final report was released on

December 1, 1980.’0

The SPS research, development, and demonstration bill, ’ which was introduced in the

House of Representatives on January 30, 1978,

reflected a desire by a number of Members of

Congress to accelerate the evaluation of SPS

and to introduce a more ambitious technology

verification effort. It was reported out by the

Science and Technology Committee after

7Robert A. Summers (chairman), “Final Report of the ERDA

Task Croup on Satellite Power Station,” report No. ERDA-76/l 48,

November 1976.

“’Solar Power for Satellites, ” hearings before the Subcommittee on Aerospace Technology and National Needs of the Committee on Aeronautical and Space Sciences, U S. Senate, J an, 19,

21,1976, GPO stock No, 66-608-0, 1976

“’Solar Satellite Power System Concepts,” hearings before the

Subcommittee on Space Science and Applications and the Subcommittee on Energy Research, Development, and Demonstration of the Committee on Science and Technology, U.S. House of

Representatives, Feb. 20,1976 (No 67)

‘“Satellite Power Systems Concept Development and Evaluation Program, “Program Assessment Report Statement of Findings, ” DOE/E R-0085, November 1980,

“Ronnie Flippo, “Solar Power Satellite Research, Development, and Demonstration Program Act of 1978, ” H .R 10601, J an.

30,1978.

another round of hearings, ’2 and eventually

passed by the full House. No Senate bill was introduced. A similar bill,13 reintroduced in 1979,

was passed by the House on November 16,

1979, but again died in the Senate.

The DOE/NASA Concept Development and

Evaluation Program14 was established to identify and evaluate the possible technical, environmental, social, institutional, and economic aspects of the SPS concept. It has generated

a broad range of reports that reflect this intent. 5

In order to have a fixed technical basis

for the study, DOE and NASA developed two

versions of a “reference” satellite power station system, based on extensive studies undertaken by two NASA contractors. 16 17 Although

the reference system represented the best

choice based on the information available at

the time, it was not intended to be the last

word in systems definition; the multitude of

other options that have been proposed since

also need to be evaluated before ultimately

settling on a “baseline” system design.

OTA was requested by the House Committee on Science and Technology to pursue an

independent study to “assess the potential of

the SPS system as an alternative source of

energy.’” 8 Hence, this study primarily addresses the benefits and drawbacks of SPS as

an energy system. It also identifies the key

“’Solar Power Satellite, ” hearings before the Subcommittee

on Space Science and Applications and the Subcommittee on

Advanced Energy Technologies and Energy Conservation Research, Development, and Demonstration of the Committee on

Sc[ence and Technology, U.S. House of Representatives, Apr

12-14, 1978 (No, 68), CPO stock No. 28-155-0, 1978,

‘ ‘Ronnie Flippo, “Solar Power Satellite Research, Development, and Evaluation Program Act of 1979, ” H R. 2335, Feb. 22,

1979

“’’Satellite Power System Concept Development and Evaluation Program Reference System Report,” U S. Department of

Energy report No DOE/E R-0023r October 1978.

‘

sSee the extensive set of references in note 10

“C Woodcock, “Solar Power Satellite System Definition

Study, ” Boeing Aerospace Co., Johnson Space Center (contract

No NAS 9-151 96), pt. 1, report No. DI 80-22876, December 1977,

pt 111, report No D18024071, March 1978

“C Hanley, “Satellite Power System (SPS) Concept Definition, ” Rockwell International Corp., Marshall Space Flight Center, (contract No. NAS 8-32475), report No. SD78-AP-0023, April

1978

“Letter of request to OTA from the House Committee on

SC Ience and Technology, Aug 8,1978
Ch. 2—Introduction ● 7 9

uncertainties of the various SPS concepts and

related needs for R&D.

Although SPS would be an energy system it

is unique in being a major space system as

well. It would therefore require a large new

commitment to the development of space

technology. Hence, this report also addresses

the relationship of an SPS program to other

space programs.

OTA has divided the assessment into four

major areas: 1) SPS technical alternatives and

economics, 2) issues arising in the public debate, 3) institutional and international questions, and 4) the programmatic context, i.e.,

the place of SPS within our national energy

and space programs. A number of working

papers were written to provide data for these

areas. OTA also convened three workshops to

refine and amplify the data presented in several of the working papers: 1) SPS Technical

Options and Costs, 2) SPS Public Opinion

Issues, and 3) The Energy Context of SPS.

●

●

• SPS technical options and costs. The major task of the workshop was to assess the

DOE/NASA reference system from a technical perspective and to study alternatives. It discussed the key uncertainties of

each major system or subsystem that has

been suggested in SPS literature and

chose four generic systems for further

evaluation in later workshops: 1) the reference system, 2) a solid-state variant of

the reference system, 3) a laser system,

and 4) a mirror system.

SPS public opinion issues. Participants

with experience in analyzing and responding to a variety of public interests and

concerns met to identify the major issues

that could affect the public perceptions

of SPS. The workshop was not an exercise

in public participation. Rather, it sought a

range of viewpoints from participants

who have a sense of the issues, the political players, and public attitudes involved.

The energy context of SPS. SPS will succeed or fail in competition with other energy supply options and in the context of

national and global demand for electricity. This workshop developed criteria for

choosing between technologies and compared the major future alternative renewable or inexhaustible sources of baseload

electrical power. Participants discussed

the many factors that wouId affect future

electricity demand and compared breeder

reactors, fusion, terrestrial solar thermal,

and solar photovoltaic baseload options.

They also discussed the potential role of

dispersed photovoltaic systems in meeting

part of the Nation’s electrical needs.

Because the SPS concept would use a complex future technology about which there are

many uncertainties, this assessment is fundamentalIy different from an assessment of current technology. While it is thought to be technically feasible, many of the details are uncertain; economic projections or possible environmental effects based on them are also uncertain, sometimes by more than an order of

magnitude. Hence at this point OTA must be

satisfied with identifying the key uncertainties

of SPS and, where applicable, suggesting alternate strategies for resolving them. The study

also analyzes the major institutional and international issues that accompany decisions

about SPS, i.e., how it may affect national

security, the international energy market, the

utilities industry, and how an SPS project

might be financed and managed. Although a

definitive treatment of any of these issues

must wait for the future, this report attempts

to lay the foundation for further consideration

of SPS.
Chapter 3

ISSUES AND FINDINGS
Contents

Page

Technical Options .. .... . . . . . . . , . . . 23

Microwave Transmission . . . . . . . . . . . . 23

Laser Transmission . . . . . . . . . . . . . . . . . 24

Reflected Sunlight . . . . . . . . . . . . . . . . . 27

SPS Scale . . . . . . . . . . . . . . . . . . . . . . . . 28

Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

SPS and the Energy Future . . . . . . . . . . . . . 30

SPS ls Not Likely To Be Commercially

Available Before 2005-15 . . . . . . . . . . 30

SPS Would Not Reduce U.S.

Dependence on lmported Oil . . . . . . . 32

Potential Scale of Electrical Power. ,... 32

Electricity Demand Would Affect the

Need for Solar Power Satellites. . . . . . 32

Comparison to Other Renewable

Options . . . . . . . . . . . . . . . . . . . . . . . . 33

Utilities. . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Nontechnical Considerations . . . . . . . . . 35

Ownership and Finance . . . . . . . . . . . . . 36

International implications . . . . . . . . . . . . . 37

National Security Implications. . . . . . . . . . 38

Public Issues... . . . . . . . . . . . . . . . . . . . . . 41

Environment and Health. . . . . . . . . . . . . . . 41

Electromagnetic Compatibility . . . . . . . . . 48

The Public . . . . . . . . . . . . . . . . . . . . . . . . 48

Space Communications . . . . . . . . . . . . . 48

Terrestrial Communications and

Electronic Systems . . . . . . . . . . .

Effect on Terrestrial Astronomy

and Aeronomy . . . . . . . . . . . . . . . .

Space Program . . . . . . . . . . . . . . . . . . . .

LIST OF TABLES

TableNo.

l, Characterization of Four Alternative SPS

Systems . . . . . . . . . . . . . . . . . . . . . . . . . . .

Page

50

50

52

Page

31

2. Major lssues Arising in SPS Debate . . . . . . . . 42

3. Summary of SPS Environrnental Impacts. . . . 43

4. SPS Systerns Land Use .

LIST OF F

Figure No.

1

2

3

4

. . . . . . . . . . . . . . . . 47

GURES

Page

The Reference System . . . . . . . . . . . . . . . . . . 24

The Solid-State Variant of the Reference

System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

The Laser Concept . . . . . . . . . . . . . . . . . . . . 26

The Mirror Concept (SOLARES) . . . . . . . . . . . 28

5. Reference System Costs . . . . . . . . . . . . . . . . . 29

6. The Number of Geosynchronous

Satellites as a Function of Time . . . . . . . . . . . 49

7. The SPS Brightness Profile . . . . . . . . . . . . . . . 51
TECHNICAL

What technical options might be available

for SPS?*

A number of technical options for the solar

power satellite (SPS) have been proposed. Because SPS is a developing technology, the specific design parameters of each of these approaches are evolving rapidly as research continues. Hence no single option is completely

defined, nor are there detailed systems studies

of any designs other than the National Aeronautics and Space Administration/Department

of Energy (NASA/DOE) “reference system”

that uses microwaves for transmitting energy

from space to Earth. The reference design is

the basis for the NASA/DOE environmental, societal, and comparative assessments. The two

other major SPS variants depend on laser transmission of power from space and on reflected

sunlight.

Microwave Transmission

The Reference System Design

The reference system satellite conceptual

design consists of a 55 square kilometer

(km

2

)** flat array of photovoltaic solar cells

located in the geostationary orbit 35,800 km

above the Earth’s Equator (fig. 1). The cells

convert solar energy into direct-current (de)

electricity that is conducted to a 1-km diameter microwave transmitting antenna mounted

at one end of the photovoltaic array. Microwave transmitting tubes (klystrons) convert the

electrical current to radio-frequency power at

2.45 gigaHertz (GHZ), and transmit it to Earth.

A ground antenna receives the electromagnetic radiation and rectifies it back to direct

current; hence its designation “rectenna.” The

direct-current (de) power can be inverted to

alternating-current (ac) and “stepped up” to

*See ch. 5.

**Equivalent to about 13,600 acres

OPTIONS

high voltage. It would then be either rectified

to dc and delivered directly to a dc transmission network in the terrestrial utility grid or

used as conventional ac power. The rectenna

covers a ground area of 102 km2 and would require an “exclusion area” around it of an additional 72 km2 to protect against exposure to

low-level microwaves. The beam density at the

center of the rectenna is 23 milliwatts per

square centimeter (mW/cm2

). The beam is

shaped in such a way that at the edge of the exclusion area it reaches 0.1 mW/cm2

.

For the given set of design assumptions for

the reference system, i.e., beam density, taper,

and frequency, the maximum power per transmitter-receiver combination would be 5,000

MW. Except for a small seasonal variation in

output due to the variation of the Sun’s distance from the Earth, and short periods of

shadowing by the Earth near the time of the

spring and fall equinoxes, each reference system satellite could be expected to deliver the

maximum amount of power to the grid approximately 90 percent of the time. This power

level was selected by NASA/DOE for the reference system in the belief that it would provide energy at the lowest cost. 1 n subsequent

discussions it is used to consider the impact of

the reference system design on utilities and

their systems; however, the power level could

be set at any value permitted by the design

constraints.

The reference system, which was developed

to provide a base for further studies and is now

several years old, is far from an optimum

microwave system and could be substantially

improved. In addition, alternative concepts

that depend on laser transmission or passive

reflection of sunlight each offer certain

specific benefits over the microwave designs.

Because none of these alternatives are as well

defined as the reference system, they are

discussed here in more general terms.

23
24 . Solar Power Satellites

Figure 1 .—The Reference System

Array

structure

Solar cell array

Transmitting antenna subarray

DC-RF

power amps

Antenna waveguides

SOURCE: C. C. Kraft, “The Solar Power Satellite Concept,” NASA publication No. JSCp14898, July 1979.

The Solid-State Variant

Using solid-state devices that convert electricity from the satellite’s solar array directly

to microwave power would be a possible alternative to the reference system’s klystrons.

Such devices might have a longer working lifetime and require less mass in orbit; when coupled with photovoltaic cells in a “sandwich”

design, they would also allow for a much larger

transmitting antenna (the entire surface area

of the solar cells would, in effect, be the antenna), smaller earthside antennas, and lower

power delivered to Earth per satellite (i.e.,

about 1,000 MW per rectenna). In combination, these effects would make it possible to

position rectennas closer to the cities, which

would be the major users of SPS generated

power, than would the reference system

design.

Solid-state devices are now in the very early

stages of being evaluated for SPS application.

It is still unclear whether they would be able to

reach the efficiency and cost goals that would

be necessary for SPS.

Laser Transmission

Lasers constitute an obvious alternative to

microwaves for the transmission of power over

long distances. Compared with microwaves,

lasers have a much smaller beam diameter;

since the aperture area of both transmitting

and receiving antennas decreases as the square

of the wavelength, light from an infrared

wavelength laser can be transmitted and received by apertures over 100 times smaller in

diameter than a microwave beam. This reduces the size and mass of the space segment

and the area of the ground segment. Perhaps

even more important, the great reduction in

aperture area permits consideration of fundamentally different systems. For example:

● It would become possible to use low Sunsynchronous rather than high geostationary orbits for the massive space power

conversion subsystem (a Sun-synchronous

orbit is a near-polar low Earth orbit that

keeps the satellite in full sunlight all the

time while the Earth rotates beneath it).

The primary laser would then beam its
Ch.3— Issues and Findings ● 25

Figure 2.—The Solid-State Variation of the Reference System

●

Reflected sunlight

Solid-state

amplifier

panel

cell

Solar array/microwave antenna

sandwich panels

SOURCE: G. M. Hanley, et al., “Satellite Power Systems (SPS) Concept Definition Study First Performance report No. SS D 79-0163, NASA MSFC

contract No. NAS8-32475, Oct. 10, 1979.

power up to low-mass laser mirror relays

in geostationary orbit for reflection down

to the Earth receiver. This arrangement,

while complex, would considerably reduce the cost of transportation, since the

bulk of the system would be in low Earth

orbit rather than in geostationary orbit. It

also could be built with smalIer transportation vehicles than the reference system’s planned heavy lift launch vehicle

(HLLV).

A laser system might be able to operate

efficiently and economically on a smaller

scale (100 to 1,000 MW). Thus, it would

offer the flexibility of power demand

matching on the ground, making possible

higher degrees of redundancy and a

smaller and therefore less costly system

demonstration project.

● The potentially small size of the receiving

station would make it possible to employ

multiple locations close to the points of

use, thereby simplifying the entire ground

distribution and transmission system.

● Laser power transmission would avoid the

problem of microwave biological effects

and would reduce overall interference

with other users of the electromagnetic

spectrum.

A laser SPS would suffer from three important disadvantages:

● Absorption of laser radiation. Infrared r adiation is subject to severe degradation or

absorption by clouds. A baseload system,

unlike the microwave option, would require considerable storage capacity to

make up for interruptions. Multiple re83-316 0 - 81 - 3
26 ● Solar Power Satellites

Figure 3.—The Laser Concept (One Possible Version)

1Solar power satellite Relay unit(s)

Ground site

Synchronous relays

Occulted

power

satellites

Sun
Ch. 3—Issues and Findings ● 27

●

●

ceivers at different locations to achieve

some redundancy are also possible, but

expensive (seeUtilities, ch. 9).

Efficiency. Current high-power, continuous-wave lasers are only capable of very

low overall power conversion efficiencies

(less than 25 percent). Converting the

beam back into electricity is also inefficient, though progress in this area has

been rapid. The relatively undeveloped

status of laser generation and conversion

means that considerable basic and applied research would be needed to determine the feasibility of a laser SPS.

Health and safety hazard. The beam intensity would be great enough to constitute a

health and safety hazard. Preventive

measures could include a tall perimeter

wall, and/or a warning and defocusing

system.

Several types of continuous wave lasers currently exist. Of these, the most highly developed and most appropriate laser for SPS would

be the electric discharge laser (EDL). At present, EDL models have achieved only modest

power levels and relatively low efficiencies

when operated in a continuous mode.

Another future option that has been considered is the solar-pumped laser. In this device,

concentrated sunlight is used directly as the

exciting agent for the laser gases. Although a

solar-pumped laser has been built and operated successfully at NASA Langley, it would require considerable basic research, development, and testing before it could be a realistic

prospect for SPS.

Free electron lasers (FELs) offer another

possible means of transmitting power from

space. These new devices are powered by a

beam of high-energy electrons which oscillate

in a magnetic field in such a way that they

radiate energy in a single direction. Although

the FEL has been demonstrated experimentalIy, it is too early to predict whether it would

reach the efficiencies and reliability necessary

for an SPS.

Reflected Sunlight

Instead of placing the solar energy

sion system in orbit, large orbiting

could be used to reflect sunlight to

based solar conversion systems. Thus,

tern’s space segment could be much

convermirrors

groundthe syssimpler

and therefore cheaper and more reliable.

One such system would consist of a number

of roughly circular plane mirrors in various

nonintersecting Earth orbits, each of which

directs sunlight to the collectors of a number

of ground-based solar-electric powerplants as

it passes over them. Conversion from sunlight

to electricity would occur on the surface of the

Earth.

In one approach, (the so-called “SOLARES

baseline” concept) about 916 mirrors, each 50

k m

2 in area, would be required for a global

power system projected to produce a total of

810 gigawatts (GW) (more than three times current U S. production) from six individual sites.

This is not necessarily the optimum SOLARES

system. It was selected here to demonstrate

the magnitude of power that might be

achieved with such a system. However, a number of different mirror sizes, orbits, and ground

station sizes are possible. A more feasible option would be a lower orbit system (2,100 km)

to supply 10 to 13 GW per terrestrial site. One

of the principal features of the SOLARES concept is that it could be used for either solarthermal or solar photovoltaic terrestrial plants.

The fact that energy conversion would take

place on the surface of the Earth keeps the

mass in orbit small, thereby reducing transportation costs.

However, a major disadvantage of such a

mirror system would be that the entire system

would require an extremely large contiguous

land area for the terrestrial segment (see table

4, p. 47). As with the laser designs, transmission

through the atmosphere would be subject to
28 • Solar Power Satellites

Figure 4.–The Mirror Concept (SOLARES)

reduction

Photo credit National Aeronautics and Space Administration

SOURCE: K. W. Billman, “Space Orbiting Light Augmentation Reflector Energy System: A Look at Alternative Systems,”

SPS Program Review, June 1979.

or elimination by cloud cover. It trical power to the United States or to other

would also illuminate much of the night sky

(see issue on electromagnetic interference) as

seen by observers within a 150-km radius of the

groundsite center.

SPS Scale

As presently conceived, the reference system is a large-scale project that has the potential of delivering hundreds of gigawatts of eleccountries. However, its very scale is seen by

many as a serious drawback to deployment.

The utilities here and abroad would find it

hard to accommodate power in 5,000 MW

blocks (see Utilities, ch. 9), and the space

transportation system needed to build and

maintain such a massive system would be very

expensive. Thus, it is of considerable interest

to investigate ways in which the scale of the

various components, and of the system itself,

couId be reduced to a more manageable size.
Ch. 3—Issues and Findings ● 29

The laser system would offer the potential

for the most substantial reductions, both in

overall system size and in the size of the first

demonstration project. This reduction in scale

might also bring with it a concomitant reduction of costs. There are also a number of possible ways in which to reduce the physical scale

of portions of the microwave system. However, economies of scale tend to drive microwave systems to sizes of 1,000 MW output or

more.

SPS would require a massive industrial infrastructure for space transportation and construction and for related terrestrial construction, comparable in scale to that developed for

existing ground-based coal and nuclear systems.

●

●

Space transportation. The reference system assumes the construction and use of a

large third-generation, shuttle-type transportation system. Construction of a single

reference system satellite (silicon photovoltaics) would require approximately 190

flights of an HLLV. However, launch vehicles somewhat larger than the current

shuttle, but smaller than the HLLV, are capable of operating with less load per flight

but with many more flights and might be

more economical. I n addition, an intermediate size vehicle would be more appropriate for other uses in space. No other

currently planned space project envisions

using vehicles the size of an HLLV.

Space construction. SPS would require

construction bases in low Earth orbit and,

for some designs, at geostationary orbit. It

might be possible to achieve substantial

cost reductions by constructing the satellites in low Earth orbit and transporting

them to geostationary orbit, rather than

by constructing them in geostationary orbit.

costs

Although the costs of many SPS components

have been estimated by a number of different

agencies, it is not yet possible to establish

them with any reasonable level of confidence.

The most detailed cost estimates have been

made by NASA for the reference system (fig. 5):

$102.4 billion to achieve the first complete

reference system satellite, and $11.3 billion to

construct each satellite thereafter.

These estimates included the costs of the entire transportation system, the costs of establishing the launch sites and construction facilities in low-Earth and geosynchronous orbits,

as well as all of the component development

Figure 5.—Reference System Costsa

(dollars in billions)

a

NASA estimates— 1977 dollars.

SOURCE: National Aeronautics and Space Administration
30 ● Solar Power Satellites

costs. However, they do not include interest on

the invested capital or the potential use of SPS

facilities for other space or terrestrial projects.

According to one possible development scenario generated by NASA (see fig. 24, p. 93), including interest of 10 percent per year more

than doubles the development cost of SPS.

By using a smaller capacity transportation

system (assuming more flights per satellite),

and apportioning the development costs of

generic space technology among all the space

programs that benefit from it, it might well be

possible to deploy a single reference satellite

for $40 billion to $50 billion, or roughly onehalf of the above estimate.

Other systems might cost more or less than

the reference system, depending on the state

of development of the alternative technologies (see table 1). For example, since lasers

would need considerable development before

they would be suitable for use in a laserpowered SPS, they would be likely to be more

expensive to develop than the microwave

SPS AND THE

How could SPS flt into the U.S. energy future

(2000-30)?*

SPS will ultimately be accepted or rejected

in the full context of future electrical demand

and supply technologies. It would compete

with other renewable or inexhaustible energy

sources such as hydro, wind, terrestrial solar,

ocean thermal energy conversion, fusion, fission breeder, and geothermal. Their technologies are all quite different; some serve a

demand for baseload, some for peaking or

intermediate needs. Together, they would constitute a mix of technologies designed to supply the full range of electrical needs for the

United States. SPS must be considered in light

of its potential contribution to this mix, as well

as of future electrical demand.

*See ch. 6, Energy section.

transmitter of the reference system; however,

some of the development cost could conceivably be borne by other laser applications,

e.g., directed energy weapons or inertial fusion. The cost of a laser demonstration satellite might well be less than the reference system demonstrator. Because of the relatively

low mass and ease of construction and operation of a SOLARES system, it may prove to be

much more attractive than other alternatives.

Cost estimates suggest that if the cost of terrestrial photovoltaics can reach the goals implied by reference system estimates, the costs

of a total SOLARES system would be less than

the reference system. More exact costs for the

SPS await further information on the details of

the preferred system. Whatever system might

be chosen, it is clear that the startup costs

would be in the tens of billions. How much of

this cost would have to be borne by the U.S.

taxpayer depends on the breadth and depth of

industrial and international interest in the development of SPS (see ch. 7).

ENERGY FUTURE

SPS Is Not Likely To Be Commercially

Available Before 2005-15

Experience with other new electric generating technologies indicates that new technologies take from 30 to 45 years to become a

significant source of electrical capacity in the

utility grid. SPS is unlikely to constitute a major exception to this rule of thumb. If a decision to develop SPS were made, some 15 to 25

years of development, engineering, and demonstration would be needed to reach a commercial SPS. However, because of the many

uncertainties surrounding SPS, it is not yet

possible to make a development decision. If,

after considerable further research a decision

is made in the next decade to proceed with

SPS, then it could be commercially available in

the period between 2005 and 2015. Several

years of operational testing beyond that would
Table 1.—Characterization of Four Alternative SPS Systems

Information matrix Reference design Solid state Laser system SOLARES (“baseline”)a

costs

R&D $400 million More R&D needed than reference system More R&D needed than reference system

$102 billion DDT&E (one sateilite) b

Relatively simple technical lower cost

Demonstration Smaller, demonstration with shuttle?

Construction

$44 billion, demonstration with shuttle?

$11,5 billion/satellite Unit cost lower, smaller rectenna $3 billion satellite (0,5 GW) $1,300 billion for 810 GW total system

Operation $200 million/yr-5GW Greater reliability, long lifetime 25 million/yr-satellite (0.5GW) Higher ground conversion cost

Dollars/kW $2,900 -19,000/kWc $1 ,800 -3,000/kW (probably low) $6,000/kW probably low) $1,500/kW (probably low)

Scale

Satellite size

Number of satellites

Power/satellite

Mass

Land use rectenna site

km2 1,000 MW

55 km2

18 km2

60 (300 GW total) Not projected

5,000 MW 1,500 MW

5 X104 tonnes/satellite, O 1 kW/kg Less mass than reference/O 1 kW/kg

174 km2 (including buffer) 50 km2

x 60=10,440 km2

35 33

5 km2

50 km2

Not projected 916 (810 GW total)

500 MW 135,000 MW

Less mass than reference/O .05 kW/kg 2 x 105

tonnes mirror system 2 kW/kg

0.6 km2

1,000 km2

1,2 7.4

Energy Electricity Electricity

Fairly centralized Less centralized

23 mW/cm2 Gaussian distribution Unknown

Electricity, onsite generation. Electricity, light

Less centralized Highly centralized

Unknown (10 mW/cm2 at edge) 1.15 kW/m2 (1 Sun)

Atmosphere

Transmission Ionosphere heating might affect telecommunications Tropospheric heating might modify weather over smaller area; problems with clouds?

Effluents Possible effects include alteration of magnetosphere (AR+); increased water content; LEO orbit, smaller size; smaller launch vehicles

formation of noctilucent clouds; ionosphere depletion

Electromagnetic

interference RFI from direct coupling, spurious noise, and harmonics: impacts on communications,

satellites etc from 245 GHz Problem for radio astronomers (GEO obscures portion of

sky always) optical reflections from satellites and LEO stations WiII change the night sky

Bioeffects Microwave bioeffects midbeam could cause thermal heating unknown effects of longterm exposure to low-level microwaves, Ecosystem alteration? Birds avoid/attracted

to beam?

National security

weapons potential GEO gives a good vantage point over hemisphere

–Provides a lot of power in space platform for surveillance, jamming–

–Requires developement of Iarge space fleet with/militarv potential–

If visible light IS used there may be problems Problem for optical astronomy, optical reflecfor optical astronomy; if Infrared IS used may tions and interference from beam; change

Increase airglow optical reflection from LEO night sky in vicin of sites

satellite

Direct beam ocular and skin damage ocular Psychological and physiological effects of 24-

damage from reflections? Other effects? Birds hour illumination not known Possible ocular

flying through WiII burn up? If visible will hazard if viewed with binoculars? Ecosystem

birds avoid? Ecosystem alterations? alteration

Direct weapon: as ABM, antisatellite, aimed at Indirect: night illumination psychological–

terrestrial targets possible weather modification

Indirect: power killer

satellite, planes space platform

Laser defend self, best, LEO more accessible

Vulnerability Satellites may need self defense system to protect against attack

Size and distance strong defenses–

Less ground sites; a lot of mirrors-redundancy; individual mirrors fragile; ground sites

still produce power in absence of space

system

International Will require radio frequency allocation and orbit assignment LEO more accessible to U.S.S.R. and high-lahtude countries, smaller parcels of energy make

Smaller parcels of energy make system more system more fiexible

flexible

Meet environmental and health standards?

asmaller saLAREs systems, e g 10 GW/sde would be possible and probably more desirable

b$loz bllllon–NASA estimate–mcludes Investment costs

cEst(mates by Argonne National Laboratory, Office of Technology Assessment, U S Con9ress

SOURCE Offlceof Technology Assessment
32 ● Solar Power Satellites

be needed before utilities developed enough

confidence in SPS to invest in it for their use

(see ch. 9).

SPS Would Not Reduce U.S.

Dependence on Imported Oil

Currently the biggest energy problem facing the Nation is dependence on unreliable

sources for imported oil. This dependence will

persist for the next two decades, since our

domestic supplies will continue to decline. We

now produce about 10 million barrels per day

(bbl/d) of petroleum liquids and this will likely

fall to 4 million to 7 million bbl/d by 2000. The

supply of abundant domestic energy resources

such as coal, solar, uranium, and natural gas

can increase but not enough to offset the decline in oil. Over this period our best opportunity for reducing dependence on imports will

be conservation, which has the potential of

cutting current dependence by more than 50

percent. However, the real problem will be the

substantial reduction in availability of world

oil for export to the United States. The total

amount of oil available is not likely to exceed

the current level of 52 million bbl/d and may

be as much as 15 percent below this level. Further, overall world demand will likely be higher

because of increased needs by less developed

countries (LDCS), including oil producing countries. As a result, the United States will find it

necessary to reduce imported oil dependence

considerably by 2000. This reduction will be

even more marked past 2000, when we can expect synthetic fuels from all sources to make a

substantial contribution. Since the SPS will not

be able to make a significant contribution until well past 2000, it cannot be expected to substitute for foreign oil. However, the satellite

could eventually begin to substitute for coalfired powerplants since coal, too, is a finite

fuel, and regardless of the outcome of the CO,

controversy, use of it for electric production

will eventually (though probably not for the

next 100 years) be reduced and reserved for

nonenergy needs, i.e., for plastics, synthetic

fiber, etc.

Potential Scale of Electrical Power

The reference system is designed to deliver 5

GW (5,000 MW) of power to each rectenna. If a

60-satellite U.S. fleet were completed, the SPS

couId deliver a total of 300 GW, an amount

nearly one-half the current total U.S. generating capacity. Converted to energy at a capacity factor of 90 percent, a 60-satellite system

would produce about 8 Qe/yr, more electrical

energy than we currently consume from all

supply sources (7.5 Qe). An international fleet

of satelIites could achieve a much greater capacity than this by placing more satellites in

geostationary orbit. A SOLARES-type system

could achieve an even greater generating

capacity on an international scale.

other proposals, such as the laser system

and variants of the microwave system might be

economical in somewhat smaller unit sizes

(500 to 1,000 MW). Precisely how much total

energy they might supply is less clear, however. For example, a laser system supplying

power in 1,000 MW units would need 300 such

satellites and ground receivers in order to

equal the capacity of a 60-satellite reference

system.

Electricity Demand Would Affect the

Need for Solar Power Satellites

The level of electricity demand in the United

States and the world will greatly affect the

time that new centralized electric generating

technologies, such as SPS, might be needed.

The demand for electricity could vary considerably over the next several decades. For

the United States, current forecasts show a

range in possible electrical demand from less

than today’s level of 7.5 Qe end-use to more

than 30 Qe by 2030. The demand level will be a

major determinant of the rate at which new

electric generating technologies need to be

introduced. At the lowest levels, all of our

baseload capacity could easily be supplied by

hydro and coal or nuclear for well into the 21st
Ch. 3—Issues and Findings ● 33

century provided C02 buildup does not preclude increased coal use. At high demand

levels, however, it is unlikely that any one

technology could provide all the needed baseIoad capacity and several possibilities would

be needed. In this case, development of SPS

may be attractive, even assuming successful

development of fusion or breeder reactors.

An emerging factor that will strongly affect

electricity demand is the success in developing

demand technologies that use electricity very

efficiently. It is likely over the next several

decades that the price of electricity will come

close enough to other forms of energy (synthetic fuels, direct solar, etc.) that the relative

efficiencies of the end-use equipment will determine which energy form is the cheapest.

Therefore, electricity demand could grow considerably if such things as very efficient space

and water heat pumps, electrochemical industrial processes, and high-capacity storage batteries are developed. If these are not forthcoming and the conventional ways of using energy–direct combustion of liquid and gaseous

fuels–continue to be most prevalent, then

electricity demand in the United States wilI not

increase rapidly if at al 1. Therefore, the eventual need for solar power satellites and other

central electric technologies would be determined as much by the development of efficient electric demand technologies as by its

economics relative to other electric energy

technologies.

Comparison to Other

Renewable Options

Ultimately the United States and the world

will choose or reject SPS as an energy supply

option on the basis of comparative costs as

well as environmental and social impacts. OTA

has generated a number of criteria for the

choice of energy technologies and compared

SPS with other renewable or inexhaustible options (fusion, nuclear breeder, terrestrial solar

thermal, and solar photovoltaic) on the basis

of those criteria (see table 16, p. 11 6). What

emerges from such comparisons is that if the

research, development, demonstration, and

testing (RDD&T) costs and the estimated cost

per installed kilowatt can be lowered significantly, SPS could compete with the alternatives on an economic basis. SOLARES, for

instance, might already be economical compared to conventional nuclear. SPS technical

uncertainties are much higher than for the

breeder, but lower than for fusion. Social costs

are extremely difficult to determine, but if

research demonstrated the microwave and

Ionizing radiation hazards to be low, SPS couId

substitute low-risk environmental hazards for

the high risks of coal or nuclear as well as contribute to an expanded space program. It

wouId take longer to commercialize than terrestrial solar or breeder, but less than fusion. I n

competition with other technologies, overall

demand for electricity, and the timing of the

commercial introduction of SPS vis-a-vis other

options wilI be crucial.

UTILITIES

Would SPS be acceptable to the utilities?* and available as their designers suggest they

The major factors that would affect the utilities’ decision about SPS technology are cost,

reliability, unfamiliarity with space systems,

and institutional questions. Only demonstration, and successful experience with an operational SPS over several years, would assure the

utilities that it is a viable technology for their

use. If the microwave systems were as reliable

*See ch 9, The Irnpl;cat;ons for the Utility /ndustry section

could be (90 percent or more), the utilities

would welcome them for baseload generation,

assuming their size and costs were also appropriate. The laser system might be of interest to

the utilities if it could be used to repower existing thermal facilities. The suggested unit size

of the laser system (500 to 1,000 MW) would fit

welI into the present size mix of terrestrial

powerplants. A mirror system with its highly

centralized, energy producing facility (10 to
34 ● Solar Power Satellites

100 GW) would be too large for the present

size mix, but would offer the potential for

some flexibility in energy production. Direct

electricity and hydrogen generation are both

possible in a SOLARES-type energy park. However, because the SPS would be an integral

part of the utility grid, it would impose certain

constraints on grid dispatch management. The

physical requirements of the rest of the utility

grid would in turn impose constraints on the

design of SPS. Integrating SPS into the grid involves several difficult system problems.

Microwave Transmission. —

● Stability. Because a microwave SPS is an

electronic system, not a mechanical one,

any power fluctuations due to beampointing errors or to large-scale component failure would be rapid (the order of a

second or less). The rest of the grid would

only be able to respond relatively slowly

(minutes), creating difficulties in controlling the frequency of current and overall

power levels in the grid. The importance

of this difficulty is directly dependent on

the size of the SPS contribution. The

smaller the output from a satelliterectenna combination, the easier it will be

to control. Some, if not all of this drawback of the microwave system could be

alleviated by including short-term battery

storage to act as a buffer between the SPS

rectenna output and the grid. The stability

of the grid would not then depend on the

stability of the microwave mode of transmission. However, buffer storage would

increase system costs. The optimum

amount of storage that might be needed

has not been determined, but cost estimates range from 0.5 to 5 percent of the

total system costs.

Load following and variations of SPS power. The rectenna output would vary seasonally depending on the distance of the

Earth from the Sun. The amount of the

variation, and the rate at which SPS power

changes, would in principle pose no technical problem for the grid.

Because any satellite that lies in a geostationary orbit experiences eclipses (1 to

72 minutes) around the equinoxes (March

●

21 and September 21) when the Earth’s

shadow falls across the satellite, a reference system satellite would suffer power

interruption. A number of satellites would

be eclipsed at one time. The rate at which

the eclipsing occurs would cause the SPS

power to fall at a rate of about 20 percent

per minute, much faster than the utility

grids are expected to be able to respond.

This could be alleviated by shutting the

satellite down slowly in advance of the

shadow, with a consequent extra small

loss of SPS power for the period, or by

including buffer storage as suggested

above. If daily load curves maintain their

current shape, the eclipse would occur

near the daily minimum (local midnight),

necessitating less backup capacity than

wouId otherwise be the case.

In principle, SPS could be designed to

follow the daily load, but because of its

high capital costs it would be uneconomical to do so. It is designed to deliver

continuous, baseload power. Hence the

burden of following any shifts in load

would be placed on conventional terrestrial intermediate load units in the utility

system.

Microwave beam positional errors. The

beam could be centered on the rectenna

by means of a pilot beam directed towards the satellite antenna from the

center of the rectenna. Because the signal

would take about 0.2 seconds to sense a

position error and correct the pointing of

the beam, the antenna output would be

subject to a potential frequency variation

of about 5Hz (5 cycles/see). Power variations of tens of megawatts from this

source could make utility grid manage

ment extremely difficult. Weather fronts

could adversely affect the position of the

beam, but the resultant power variation

would be slow. Again, buffer storage

could be used to alleviate these difficulties.

Because the difficulties posed by each of

the above factors increase with size, the

utilities might not find the single 5,000-MW

unit proposed by the reference system accept-
Ch. 3—Issues and Findings ● 35

able even in the future. Although nuclear, fusion, or coal energy parks having about 5,000

MW total capacity have been proposed, they

would be composed of several smaller units,

each of which are only about 1,000-MW capacity. In addition, in planning for overall system

reliability, utilities generally use the criterion

that no single unit in the system can account

for more than 10 to 15 percent of the total

system. Thus, in order to place a 5,000-MW

unit in the grid, the grid should have a total

system capacity of 33,000 to 50,000 MW. At

current rates of electrical growth (3.2 percent

per year), only the Tennessee Valley Authority

(TVA), the country’s largest utility, will have a

grid large enough to accommodate a 5,000-

MW SPS in 2000. TVA currently has a capacity

of 23,000 MW, but it has stopped construction

on several new powerplants because of slower

demand growth. A national power grid might

alleviate the problem of utility grids being too

small to accommodate a 5,000-MW SPS.

Laser Transmission.— From the utilities’ perspective, the most serious difficulty facing

laser transmission is absorption by clouds.

Although in a few locations in the country it

appears to be technically possible to switch

from a cloud covered area to one that is cloudfree, utilities would have little incentive to

construct the extra facilities to accommodate

such switching unless the economic benefits

were commensurate with the expense of the

extra facilities. In general, the various sites are

unlikely to be all in the same service area, further complicating the ability of the utility to

follow the load.

Mirror Reflection. —

●

●

Reflection of sunlight from space suffers

from the same disadvantage as that of the

laser option: the reflected beam could

easily be degraded or occluded by cloud

cover. it has been suggested that the additional radiant energy might be enough to

dissipate clouds, but this might have

detrimental environmental effects and

alter weather patterns over a wide region

around the energy park.

As conceived in the “baseline” case, the

mirror system would require large energy

parks capable of producing more than 100

GW. Smaller parks of 10 GW might also

be possible. Even the relatively smaller

parks would necessitate major changes in

current utility operation and load management. Among other changes, such

parks would necessitate building an extensive new network of major transmission

lines to distribute electrical power from

remote receiving areas to end-users.

In principle, all of the technical problems

for the different systems are resolvable at

some cost. However, they would require considerable further study and testing as well as a

close look at the system economics.

Nontechnical Considerations

In addition to the technical difficulties that

SPS can be expected to face, there are a

number of potential institutional barriers to

SPS acceptance by U.S. utilities:

●

●

SP5 as a space system. The current utility

management and regulatory infrastructure is much more receptive to the terrestrial renewable or inexhaustible options— breeder reactor and fusion for

baseload, and solar thermal and solar

photovoltaic for intermediate and peaking loads.

Regulatory framework. Utilities are currently regulated on a State or local basis.

SPS could be expected to hasten the move

towards greater centralization of the regulatory process (i.e. Federal level). A

SOLARES-type SPS, because of its large

centralized energy parks, would make a

high degree of centralization mandatory.

However, other SPS modes may also lead

to more centralized regulation, particularly if the SPS were constructed and managed by a federally chartered monopoly

(see Ownership and Finance) or Government agency.

Nuclear powerplants are currently regulated at the Federal and State level for

health, safety, and environmental impacts. However, their effect on the rate

structure is regulated at the State and
36 . Solar Power Satellites

local level. An SPS corporation might lead

to Federal involvement in setting rates for

power as well as regulating SPS technology. The utilities and local regulatory

agencies could be expected to resist any

pressures toward greater Federal involvement in what has traditionally been their

province.

Ownership and Finance

Electric utilities currently face a serious

problem raising the capital necessary to install

new generating capacity. Because of this, and

because they lack launch and space construction capability, they are unlikely to own or

operate the space segment of an SPS system

directly; they could more easily be responsible

for the ground receivers. This raises the question of how domestic SPSs would be financed

and managed.

The central issues are: 1 ) the degree and kind

of government involvement; and 2) how to differentiate between the R&D and construction/

operation phases.

● Government involvement. The arguments

for Government financing and ownership

wouId be that the high fronnt-end costs and

high-risk long pay-back times inhibit private sector investment, and that lack of

competition would necessitate Government ownership. Certain aspects of TVA

or NASA could provide possible guidance

for SPS ownership and operation.

On the other hand, it can be argued that

direct Government involvement is contrary to American preference for private

enterprise, that centralized control would

lead to inefficiencies, and that U.S. Government ownership would make military

participation far more likely. Furthermore, it is feared that Government investment in SPS would drain resources from

other energy technologies that need

Federal support. A Government-chartered

but privately owned and operated company similar to Comsat, or a regulated

private monopoly such as AT&T, might be

preferred. Since the United States is party

to international law that requires national

governments to bear the responsibility for

space activities, even when carried out by

nongovernmental entities, some degree of

Federal supervision and involvement will

be required in any case.

R&D and operating phases. Raising private

capital would be especially difficult during the research, development, and demonstration phase. A successful prototype

demonstration would probably be necessary to attract private investment. If SPS

is judged to be a feasible energy option,

prototype development is likely to require

Federal funding, perhaps via taxes, similar

to the Interstate Highway System trust

fund, or through “Space Bonds.” After

that, it is likely that Government loans or

guarantees would be required, at a minimum. At some stage the technology could

be turned over to the private sector. Instances of such practices have included

nuclear reactors, first developed for military use in submarines; and telecommunications technology, funded by NASA and

then turned over to Comsat and commercial carriers. Clarification of current patent provisions for NASA and other Government research contracts would facilitate such transfers. Upcoming examples

that should be examined for their applicability to SPS are the Space Shuttle,

which has been developed by NASA but

may eventually be turned over to private

enterprise, due to restrictions on NASA

operation of commercial ventures; the

newly established U.S. Synfuels Corp.,

which is intended to provide money for a

variety of private synthetic fuels ventures;

and the European Space Agency’s (ESA)

Ariane launcher, which will be operated

by a private consortium called Arianespace. Private joint ventures, such as

Satellite Business Systems or the Alaska

pipeline consortium, are another possible

way to establish a “Solarsat” Corp. for the

construction and operating phases.

A combination of the suggested models, involving different degrees of Government and private financing, may be more
Ch. 3—Issues and Findings ● 37

feasible than any of the specific models the ability of an SPS organization to atmentioned. Providing for a smooth transi- tract foreign capital and to involve fortion between public and private invest- eign participants at early stages of develment phases would be an important con- opment. (See International Implications.)

cern. A critical consideration should be

INTERNATIONAL IMPLICATIONS

What are the international implications of

solar power satellites?*

Development and construction of an SPS

system would necessarily involve a number of

international dimensions. At a minimum, current and future international treaties and

agreements, especially those dealing with the

allocation of the electromagnetic spectrum,

would require consultation with foreign states

and multinational organizations. Beyond this,

there may be good reasons to consider an active multilateral regime to regulate, build,

and/or operate the SPS.

International organizations, multinational

corporations, and domestic interest groups will

all be involved in SPS decisions. However, due

to the SPS’s cost, benefits, and military/foreign

policy impacts, which would directly affect

the vital national interests of other nations involved, such decisions will ultimately be made

at the national level by political leaders.

Economic lmpact.– If successful, the SPS

promises to deliver significant amounts of

electricity y. Estimates of future global electricity demand by the International Institute

for Applied Systems Analysis (IIASA) indicate

that, even with low rates of economic growth,

electricity usage will increase by a factor of 4

over the next 50 years. Regional variations in

growth rates will be considerable, with

developed countries increasing at a much

slower rate than developing ones. Recent

studies for the United States that take into account marked reductions in usage rates, such

as the National Academy of Sciences’ Energy

in Transition 1985-2010 indicate that demand

in the developed countries may remain con-

*See ch. 7.

stant or rise only SIightly over the next 30 years.

On a global scale, this might indicate a rise less

than that predicted by IIASA. Meeting this demand will be particularly difficult in energyscarce areas such as Western Europe, Japan,

and much of Latin America, Africa, and South

Asia. Countries in these regions will be

especially interested in SPS development.

Noneconomic Impact. -The noneconomic

effects of SPS would influence the decisions of

the major space powers, the United States and

the U.S.S.R. The prestige of such a major space

and energy accomplishment would be considerable. The military advantages of high-capacity launch vehicles and a large energy-producing platform in high orbit would be significant,

even if SPS were not used for direct military

purposes.

The United States and the U.S.S.R. both

have extensive conventional energy sources–

oil, coal, oil shale, and uranium. Thus, neither

country can be expected to develop an SPS

unilaterally unless unpredictable obstacles to

the use of coal and/or nuclear power develop.

SPS is therefore likely to be pursued in conjunction with foreign partners who contribute

capital and expertise and buy completed satellites. Both Western Europe and Japan, who

have extensive space programs and a history of

cooperation with the United States, would be

probable partners. Soviet secrecy and military

domination of their space program makes international cooperation on their part unlikely.

International Cooperation.– Experience with

multilateral organizations suggests that estabI The global estimates cited in Energy in Transition, however,

are similar to I IASA’S; a rise of three to five times in electricity

consumption by 2010. See Energy in Transition, National

Academy of Sciences, 1979, p. 626.
38 . Solar Power Satellites

Iishing and running a successful international

venture would be difficult. Reconciling the different interests of the participants regarding

overall system design, decision making, and

allocation of contracts and financial returns

would be time-consuming and might compromise timely and efficient results. The example

of Intelsat suggests the importance of strong

national support by interested parties, of

independent corporate management, and a

profit-incentive. However, it is unlikely that an

agency modeled on Intel sat could be duplicated today for SPS. In particular, the role of

LDCs would be greater and could be disruptive

unless North-South conflicts can be kept from

dominating day-to-day decisions. Strong

leadership by the United States and the Organization of Economic Cooperative Development partners would be required to maintain an effective program.

International Law.– International law currently requires allocation of satellite frequencies and geostationary positions by the international Telecommunication Union (ITU). If

SPS were to interfere with global communications, this could be a major obstacle to gaining

ITU approval. ownership and control of the

geostationary orbit has not been completely

resolved, and attempts by equatorial states to

claim sovereignty over it could hamper development of any geostationary SPS. The proposed Moon Treaty, which calIs for an international regime based on the principle of the

Common Heritage of Mankind, provides a

precedent for international control over space

resources, and may affect plans to construct

SPS from lunar materials. In each of these

cases it can be expected that future LDCs will

seek to gain leverage over any SPS regime by

controlling access to space. Accommodating

LDC interests in a manner compatible with SPS

development may be difficult or politically impossible; the precedent set by the uncompleted Law of the Sea negotiations should be

carefulIy considered.

Military Impact. – The military uses of an SPS,

especially for directed-energy weaponry,

would be restricted by the 1972 Anti-Ballistic

Missile (ABM) Treaty and by provisions in the

1967 Treaty on Principles Governing the Activities of States in the Exploration and Use of

Outer Space banning weapons of “mass

destruction” in orbit. Although SPS would not

lend itself to efficient use as a weaponssystem, * objections to the SPS on military

grounds, and demands for inspection and/or

redesign to preclude military uses, can be expected. Multilateral development would alleviate many such problems.

Foreign Interests.—To date, space agencies

and private firms in foreign countries such as

England, France, West Germany, and Japan,

along with ESA, have expressed interest in SPS.

Most foreign studies have focused on regional

applications; technical and operational studies

have been done almost exclusively in the

United States. Soviet interest has been expressed for several years, with several technical papers published, but no details are

known. Third World interest has been informal

and cautiously favorable. Future discussion at

the United Nation’s Committee on the Peaceful Uses of Outer Space and other international bodies will be forthcoming. Any further

U.S.-sponsored study of SPSs must take into

account international participation in SPS

development, and demand for SPS power, in

order to evaluate properly the feasibility of

SPS programs.

——.

‘See ch 7, Military Uses of SPS section

NATIONAL SECURITY IMPLICATIONS

What are the national security implications The military importance of SPS would derive

of SPS?* from its very large size, its geostationary orbital position (for certain designs), and its ability to provide tremendous amounts of power.

*For extended discussion see ch, 7 Aside from the important result of reducing
Ch. 3—Issues and Findings ● 39

the user state’s dependence on imported

energy, SPS would be strategically significant

as a target, as the catalyst for new space

transportation and construction capabilities,

and as a possible weapons-system.

Vulnerability. –A full-scale SPS system

wouId constitute a high-value target for enemy

action. Whether an SPS would in fact be

targeted in the event of hostilities will depend

above all on how crucial it is to a country’s

electrical supply. Can SPS power be made up

from other sources? Is the attacker vulnerable

to a counter-attack in kind? Best estimates are

that an SPS system would be unlikely to constitute more than 10 to 20 percent of total

generating capacity, in the countries that use

SPS, over the next 50 years. Holding SPS to this

percent would make it possible to replace SPS

power from conventional reserve capacity.

However, usage could be much higher in specific regions or industries. A widespread national grid could alleviate the threat of SPS

outages. In general, SPS would be no more

VuInerable than other major energy systems.

SPSs could be attacked in a number of ways:

1) by ground-launched missiles carrying nuclear or conventional warheads, 2) by orbiting

antisatellite platforms, 3) by ground- or spacebased directed-energy weapons, 4) by strewing

debris in the satellite’s path, and 5) by interfering with or redirecting the SPS’s energy

transmission beam.

The large size of most SPS options would

make it difficuIt for conventional explosives to

do serious damage. Lasers would likely be

more effective. Strewing debris in geosynchronous orbit would destroy a reference

system SPS, but also affect many other targets,

including friendly and neutral spacecraft.

Beam interference would be less damaging

and would require special preparation to protect against. Nuclear weapons could damage

SPSs by direct blast, and also by the electromagnetic pulse (EMP) effect, which might

overload the satellite’s electrical systems — a

large (1 megaton or more) nuclear explosion

could damage a photovoltaic SPS at ranges up

to hundreds of kilometers.

The use of nuclear weapons outside of a major nuclear exchange would carry great dangers of escalation. Any attack, nuclear or conventional, would depend on perceptions of

whether SPS is considered part of national territory and how leaders would react to such a

provocation. The analogy to ships on the high

sea suggests that an SPS in orbit might be considered fair game even short of full-scale war.

Attacks on SPS would also be affected by

whether the SPS was manned; destroying an

unmanned craft might be undertaken as a relatively unprovocative demonstration of will. At

present, neither the United States nor the

U.S.S.R. has the ability to attack objects in

geosynchronous orbit, but both are working on

various antisatellite devices and there appear

to be no insurmountable obstacles to their

development.

Defense of space craft is possible through:

1) maneuverability, 2) hardening, and 3) antimissile defenses.

The SPS would be too large and fragile to

evade attack. Hardening against explosives or

EMP bursts would add significantly to weight

and costs, and could not be effective against a

determined attack. Stationing missile or satellite defenses on a geostationary SPS, whether

directed-energy weapons or antimissile missiles, would be feasible due to the power

generated by the SPS and its position at the top

of a 35,800-km “gravity well”. However, such

weapons would have unavoidable offensive

capabilities and would therefore invite attack.

Defense of civilian SPSs could probably be

best done by independent military forces, on

the ground or in space, rather than by turning

the SPS itself into a space-fortress.

Receiving antennas or (for the mirrorsystem) PV ‘parks’ would make unattractive

targets due to their large size and redundancy;

they would certainly be no more vulnerable

than other generating facilities. It should be

noted that the SOLARES system could continue to produce power, albeit at approximately one-fifth rated capacity, by operating on

ambient sunlight even if the space mirror

system were destroyed.
40 . Solar Power Satellites

Military Uses. –The military usefulness of an

SPS stems from: 1) the launchers and other facilities used to construct the satellite portion;

2) the energy beams used by the SPS to transmit power; and 3) its strategic orbital location.

HLLVS or other transportation and construction systems would be perhaps the most direct

military benefit of SPS. These could be used by

the military to build large space platforms for

communications, surveillance, or weaponry.

Such activities might be disguised by being

carried out during SPS construction, but it is

unlikely that they could escape detection by

interested parties. Development of such systems would be most important, and destabilizing, in providing a “break-out” capacity for

rapid emergency deployment of military satellites by fleets of SPS construction vehicles.

Laser beams built as part of SPS, or more

militarily efficient weapons placed on the SPS

but not used in transmitting electricity, could

be used as strategic weapons. In recent years

both the United States and the U.S.S.R. have

undertaken large programs to develop directed-energy weapons for use against satellites and/or international ballistic missiles

(ICBMs). However, a geostationary SPS is

35,800 kilometers distant from low-flying

ICBMs. This distance complicates tracking and

requires very high beam intensities. Much

greater effectiveness can be achieved by

weapons placed in lower orbits. However, a

geostationary SPS could play a role in supplying power to remotely located directed-energy

platforms. A laser SPS in low Sun-synchronous

orbit, of course, would represent a much

greater military potential than one in geosynchronous orbit.

Use of SPS, even indirectly, for ABM purposes is currently prohibited by the 1972 ABM

Treaty. A militarily effective SPS would be a

major factor in strategic planning and would

likely be a subject of arms-control negotiations

between interested states. Provisions for direct

inspection, or design specifications to reduce

an SPS’s military usefulness, could be negotiated to reduce the various threats it poses.

Such provisions might be needed even if SPS

would not be militarily useful, but was nevertheless perceived to be a military or political

threat.

Using an SPS directly against targets on the

ground would ease tracking requirements.

High-energy lasers (H EL) or particle-beams

could conceivably be used to destroy quickly

tactical targets such as ships, planes, or oil

refineries without jeopardizing one’s own personnel or risking the use of nuclear weapons.

However, SPS lasers used for energy transmission would probably not make effective

weapons without considerable modification.

SPS could also be used to supply electrical

power to military units in remote areas, and

perhaps even directly to ships or planes.

SPS could serve as a platform for certain

surveillance and communications needs. Because of its power, it might be especially

suited for conducting jamming and electronic

warfare operations.

SPS platforms, because of their size and

facilities, would be likely to serve as multipurpose space bases similar to major seaports. If

military units used SPS for resupply or rest and

recreation, it might be difficult to separate

military from civilian uses, or to convince outside observers that SPS was not a military

threat.

Any such direct uses of SPS would be determined by the way in which future SPSs are

built and managed. Construction by an independent multinational enterprise would reduce any state’s ability to use an SPS for military purposes; conversely, unilateral development would enhance it. Use of SPSs as

weapons platforms by future superpowers

would invite considerable foreign criticism,

especially if such attempts interfered with

their electricity-generation function. A sudden

diversion of SPS power to the military in time

of crisis could lead to domestic and/or foreign

electricity shortages, resulting in legal or

diplomatic protests.
Ch. 3—Issues and Findings ● 41

PUBLIC

The SPS debate: what are the issues arising in

the public arena?*

While public awareness of SPS is growing,

most discussion has been confined to a small

number of public interest groups and professional societies. In general, many of the individuals and groups who support the development of SPS also advocate a vigorous space

program. The L-5 Society has been a particularly vocal SPS supporter and views the

satelIite system as an important stepping-stone

in the colonization of space, a goal to which

the society is dedicated. The SUNSAT Energy

Council, a group formed to promote interest in

SPS, believes that it is one of the most promising options available for meeting future global

energy and resource needs. Professional associations such as the American Institute of

Aeronautics and Astronautics (AIAA) and the

Institute of Electrical and Electronics Engineers (1 E E E), have supported continued research and evaluation of the concept.

Many opponents of SPS are concerned that

it wouId drain resources from the development

of terrestrial solar technologies. The Solar Lobby and other public interest groups argue that

compared to these ground-based solar options,

SPS is inordinately large, expensive, and com-

‘See ch 9, Issues Arising in the Public Arena section

ENVIRONMENT

How would SPS affect human health and the

environment?*

As an energy system operating both in space

and on Earth, SPS involves some rather diverse

and unique environmental issues (see table 3).

While one advantage of SPS is that it would

avoid many of the environmental risks typically related to conventional energy options

such as nuclear and coal, it would also

generate some unconventional environmental

*See ch. 8.

83-316 0 - 81 - 4

ISSUES

plex, and that it poses greater environmental

and military risks while precluding local decisionmaking. Many opponents also maintain

that all future energy demand can be easily

met with existing and future terrestrial energy

technologies; there is little need to develop

SPS, especially in view of the formidable costs

to initiate the technology and the highly uncertain cost of the product. The Citizen’s Energy

Project (CEP) has been an active lobbyist

against Government funding of SPS and has

coordinated the Coalition Against Satellite

Power Systems, a network of solar and environmental organizations. Objections to SPS have

also been raised by individuals in the professional astronomy and space science communities who see SPS as a threat to the funding

and practice of their respective sciences. In the

future, it is conceivable that antinuclear, antimilitary and tax groups could also join the opposition.

Public opinion about SPS can be influenced

by a multitude of factors; concerns articulated

today may not be as important in the future. In

addition, in much of the current public discussion, SPS is treated as a U.S. system alone. If

SPS were to be developed on an international

basis, the flavor of present opinion could

change. Currently, debate about SPS focuses

on the question of R&D funding. This and

other issues are highlighted in table 2.

AND HEALTH

effects which are poorly understood at present. The resolution of the uncertainties

associated with these effects is critical to the

assessment of the environmental acceptability

of SPS. More research is needed to understand

and quantify these impacts and to investigate

modified system designs that would minimize

environmental risks. At present, there are three

major areas of concern.

1. Bioeffects of Electromagnetic Radiation.—

The effects of exposure to SPS power transmission and high-voltage transmission lines
42 . Solar Power Satellites

Table 2.—Major Issues Arising in SPS Debatea

Pro

R&D funding

. SPS is a promising energy option ●

. The Nation should keep as many energy options open as ●

possible

● An SPS R&D program is the only means of evaluating the merit ●

of SPS relative to other energy technologies

● SPS R&D will yield spinoffs to other programs

cost

● SPS is likely to be cost competitive in the energy market ●

. Cost to taxpayer is for R&D onIy and accounts for smalI portion ●

of total cost; private sector and/or other nations will invest in production and maintenance

. SPS will produce economic spinoffs

Environment, health and safety

● SPS is potentialIy less harsh on the environment than other

energy technologies, especially coal

Space

● Space is the optimum place to harvest sunlight and other

resources

● SPS could be an important component or focus for a space

program

. SPS could lay the groundwork for space industrialization and/or

colonization

. SPS would produce spinoffs from R&D and hardware to other

space and terrestrial programs

International considerations

● One of the most attractive characteristics of SPS is its potential

for international cooperation and ownership

. SPS can contribute significantly to the global energy supply

. SPS is one of the few options for Europe and Japan and is well-

-suited to meet the energy and resource needs of developing

nations

● An international SPS wouId reduce concerns about adverse

military implications

Military implications

● The vulnerability of SPS is comparable to other energy systems

● SPS has poor weapons potential

• As a civilian program, SPS would create little military spinoffs

Centralization and scale

● Future energy needs include large as well as small-scale supply

technologies; urban centers and industry especially cannot be

powered by small-scale systems alone

. SPS would fit easily into an already centralized grid

Future energy demand

● Future electricity demand will be much higher than today

● High energy consumption is required for economic growth

● SPS as one of a number of future electricity sources can contribute significantly to energy needs

. Even if domestic demand for SPS is low, there is a global need

for SPS

●

●

●

●

●

●

●

●

●

●

●

●

●

●

●

●

SPS is a very high-risk, unattractive technology

Other more viable and preferable energy options exist to meet our

future energy demand

SPS would drain resources from other programs, especially terrestrial solar technologies and the space sciences

No matter what the result of R&D, bureaucratic inertia will carry a

Government program too far

SPS is unlikely to be cost competitive without Government subsidy

Like the nuclear industry, SPS would probably require ongoing

Government commitment

Projected costs are probably underestimated considerably

The amount of energy supplied by SPS does not justify the cost

SPS risks to humans and the environment are potentially greater

than those associated with terrestrial solar technologies

Major concerns include: health hazards of power transmission and

high-voltage transmission lines, land use, electromagnetic interference, upper atmosphere effects, and “skylab syndrome”

SPS is an aerospace boondoggle; there are better routes to space

industrialization and exploration than SPS

SPS is an energy system and should not be justified on the basis

of its applicability to space projects

SPS could represent a form of U.S. of industrial nations’ “energy

imperialism”; it is not suitable for LDCs

Ownership of SPS by multinational corporations would centralize

power

Spinoffs to the military from R&D and hardware would be significant and undesirable

Vulnerability and weapons potential are of concern

SPS would augment and necessitate a centralized infrastructure

and reduce local control, ownership, and participation in decisionmaking

The incremental risk of investing in SPS development is unacceptably high

Future electricity demand could be comparable to or only slightly

higher than today’s with conservation

The standard of living can be maintained with a lower rate of

energy consumption

There is little need for SPS; demand can be met easily by existing

technologies and conservation

By investing in SPS development, we are guaranteeing high energy

consumption, because the costs of development would be so great

arguments mainly focus on the SPS reference sYstem

SOURCE: Office of Technology Assessment.
Ch. 3—Issues and Findings ● 4 3

Table 3.—Summary of SPS Environmental Impacts

System component

characteristics Environmental impact

Occupational health

Public health and safety and safety

Power transmission

Microwave —b

Ionospheric heating could

disrupt telecommunications.

Maximum tolerable power

density is not known.

Effects in the upper

ionosphere are not known.

—Tropospheric heating could

result in minor weather

modification.

—bEcosystem: microwave bioeffects (on plants, animals,

and airborne biota) largely

unknown; reflected light

effects unknown.

—

b

potential interference with

satellite communications,

terrestrial communications,

radar, radio, and optical

astronomy.

—bEffects of Iow-level —Higher risk than for

chronic exposure to micro- public; protective

waves are unknown. clothing required for

— Psychological effects of terrestrial worker.

microwave beam as weapon. —Accidental exposure to

—Adverse aesthetic effects high-intensity beam in

on appearance of night sky. space potentially severe

but no data.

Lasers

Mirrors

Transportation and

space operation

Launch and recovery

HLLV

PLV

COTV

POTV

—Tropospheric heating could

modify weather and spread

the beam.

—Ecosystem: beam may

incinerate birds and

vegetation.

—b

potential interference

with optical astronomy,

some interference with

radio astronomy.

—b

Tropospheric heating

could modify weather.

—Ecosystem: effect of 24-

hr Iight on growing.

cycles of plants and circadian rhythms of animals.

—b

potential interference

wit h optical astronomy.

—Ground cloud might pollute

air and water and cause

possible weather modification; acid rain

probably negligible.

—bWater vapor and other

launch effluents could

deplete ionosphere and

enhance airglow. Resultant disruption of communications and satellite

surveillance potentialy

important, but uncertain.

—

b

possible formation of

noctilucent clouds in

stratosphere and mesosphere; effects on climate

are not known.

—Ocular hazard?

—Psychological effects of

laser as weapon are

possible.

—Adverse aesthetic effects

on appearance of night

sky are possible.

—Ocular hazard?

—Psychological effect of

24-hr sunlight.

—

b

Adverse aesthetic effect s

on appearance of night

sky are possible.

—Noise (sonic boom) may

exceed EPA guidelines.

—Ground cloud might affect

air quality; acid rain

probably negligible.

—Accidents-catastrophic

explosion near launch

site, vehicle crash, toxic

materials.

—Ocular and safety

hazard?

—Ocular hazard?

—

bSpace worker’s hazards :

ionizing radiation

(potentially severe)

weightlessness, life

support failure, long

stay in space,

construction accidents

psychological stress,

acceleration.

—Terrestrial worker’s

hazards: noise, transportation accidents.
44 ● Solar Power Satellites

Table 3.—Summary of SPS Environmental Impacts—Continued

System component Occupational health

characteristics Environmental impact Public health and safety and safety

—bEmission of water vapor

could alter natural

hydrogen cycle; extent and

implications are not wellknown.

—bEffect of COTV argon ions

on magnetosphere and

plasma-sphere could be

great but unknown.

—Depletion of ozone layer

by effluents expected to

be minor but uncertain.

—Noise.

Terrestrial activities

Mining —Land disturbance —Toxic material exposure. —Occupational air and

(stripmining, etc.). — Measurable increase of water pollution.

—Measurable increase of air and water pollution. —Toxic materials exposure.

air and water pollution. — Land-use disturbance. —Noise.

—Solid waste generation.

—Strain on production

capacity of gallium

arsenide, sapphire, silicon,

graphite fiber, tungsten,

and mercury.

Manufacturing —Measurable increase of —Measurable increase of —Toxic materials exposure.

air and water pollution. air and water pollution. —Noise.

—Solid wastes. —Solid wastes.

—Exposure to toxic

materials.

Construction —Measurable Iand —Measurable land —Noise.

disturbance. disturbance. —Measurable local

—Measurable local increase —Measurable local increase increase of air and water

of air and water pollution. of air and water pollution. pollution.

—Accidents.

Receiving antenna —b

Land use and siting. —

b

Land use—reduce d — Waste heat.

—Waste heat and surface property value, aesthetics,

roughness could modify vulnerability (less land

weather. for solid-state, laser

opt ions; more for reference

and mirrors).

High-voltage —b

Land use and siting. —

bExposure to high intensity —bExposure to high

transmission lines —bEcosystem: bioeffects Of EM fields—effects intensity EM fields—

(not unique to SPS) powerlines uncertain. uncertain. effects uncertain.

almpacts based on SPS systems as currently defined ancl do not account for offshore receivers or poss!ble miti9atin9 sYstem modifications.

bResearch priority.

SOURCE: Office of Technology Assessment.
Ch. 3—Issues and Findings ● 45

(HVTL) on humans, animals, and plants are

highly uncertain. The existing data base is incomplete, often contradictory and not directly

applicable to SPS. While the thermal effects of

microwave radiation (i. e., heating) are wellunderstood, research is critically needed to

study the consequences of chronic exposure to

low-level microwaves such as might be experienced by workers or the public outside of

the receiver site. The biological systems that

may be most susceptible to microwaves

include the immunological, hematological

(blood), reproductive, and central nervous systems. The DOE SPS assessment has sponsored

three studies of the effects of low-level microwaves on bees, birds, and small mammals. No

significant effects have been observed, but the

experiments are far from complete. More research is vitally needed to expand the experimental and clinical data base, and to improve

theories which may facilitate the extrapolation

from animal studies to assessments of human

health hazards.

It appears that the United States will establish a microwave standard in the near future

that is more stringent than the present occupational 10.0 mW/cm2 voluntary guideline (the

new occupational standard at 2.45 GHz will

probably be 5.0 mW/cm2

), thereby approaching the standards in other countries (e. g.,

Canada: population —1.0 mW/cm2

, occupational —5.0 mW/cm2

; U. S. S. R.: population—

0.001 mW/cm2

, occupational —0.01 mW/cm2).

This does not have an immediate impact on

SPS Iand use for the reference system, since it

is designed to produce less than 1.0 mW/cm2 at

the rectenna boundary and less than 0.1 mW/

cm2 outside the rectenna boundary. Nevertheless, establishing population standards that are

more stringent couId mean more land for each

buffer zone and could affect system design

(power density and beam taper) as well as

public opinion.

With respect to spaceworkers, exposure to

ionizing radiation (including that from the

radiation belts, galactic cosmic rays, and solar

flares) would be a health hazard unless steps

are taken in future planning to minimize dose.

Studies are needed to determine acceptable

exposure limits. Research is needed to determine more precisely the expected dose rates,

the types and energies of ionizing particles,

and the effectiveness rate of various types and

thicknesses of shielding. The results will determine the number of spaceworkers, the duration of the stay, the mass needed in orbit (for

shielding), and space suit and system designs.

All of these impacts may strongly affect SPS

costs and feasibility.

For SPS systems other than the microwave

designs, very little assessment of the health

and safety effects has been conducted. The

power density of a focused laser system beam

could be sufficiently great to incinerate some

biological matter. Outside the beam, scattered

laser light could constitute an ocular and skin

hazard. More study would be needed to quantify risks, define possible safety measures and

explore the effects of long-term exposure to

low-level laser light.

The light delivered to Earth by the mirror

system, even in combination with the ambient

daylight, would never exceed that in the desert

at high noon. The health impacts that might be

adverse include psychological and physiological effects of 24 hour per day sunlight and

possible ocular damage from viewing the mirrors, expecialIy through binoculars.

2. Effects on the Upper Atmosphere.– Atmospheric effects result from two sources: heating

by the power transmission beam and the emission of launch vehicle effluents. While the

most significant effect of the laser and mirror

systems is probably weather modification due

to tropospheric heating, ionospheric heating is

most important for the microwave systems

operating at 2.45 GHz. Of most concern is

disruption of telecommunications and surveillance systems from perturbations of the ionosphere. Experiments indicate that the effects

on telecommunications of heating the lower

ionosphere are negligible for the systems

tested. As a result, a few researchers have suggested that microwave power densities of up

to 40 to 50 mW/cm2

, or two times the level

assumed for the reference design, could be

used before significant heating would occur.
46 ● Solar Power Satellites

The largest uncertainty is related to heating

and nonlinear interactions in the upper ionosphere. To investigate the heating effects in

this region, more powerful heating facilities

would be required.

The atmospheric effects resulting from the

emission of rocket effluents from SPS space

vehicles are of concern because of the unprecedented magnitude and frequency of the

projected SPS launches. In the magnetosphere,

construction of the SPS reference system as

presently designed would lead to a dramatic

increase in the naturally occurring abundance

of argon ions (from the electric propulsion

system proposed for orbital transfer) and

hydrogen atoms. While several possible effects

have been identified, including enhanced airglow and Van Allen belt radiation, and altered

atmospheric electricity and weather, the likelihood and severity of these effects are highly

uncertain.

The injection of water vapor at lower altitudes would significantly increase the water

content relative to natural levels. One possible

consequence is an increase in the upward flux

of hydrogen atoms through the thermosphere.

Another consequence of increasing the concentration of water in the upper atmosphere

might be the formation of noctilucent clouds

in the mesosphere. While global climatic effects of these clouds appear unlikely, uncertainties remain.

The injection of rocket exhaust, particularly

water vapor, into the ionosphere could lead to

the depletion of large areas of the ionosphere.

These “ionospheric holes” could degrade telecommunication systems that rely on the ionosphere. While the uncertainties are greatest for

the lower ionosphere, experiments are needed

to test more adequately telecommunications

impacts and to improve our theoretical understanding of chemical-electrical interactions

throughout the ionosphere.

In the troposphere, ground clouds generated

during liftoff could modify local weather and

air quality on a short-term basis.

Additional experiments and improved atmospheric theory are needed to understand

and quantify the above impacts under SPS

conditions. In addition mitigating steps such as

trajectory control, alternate space vehicle

design, and the mining of lunar materials need

to be assessed. Atmospheric studies would

play a major role in the choice of frequency

for power transmission.

3. Land Use and Receiver Siting.– Receiver

siting could be a major issue for each of the

land-based SPS systems. Offshore siting and

multiple use siting might each alleviate some

of the difficulties associated with dedicated

land-based receivers, but require further study.

There are two components to the siting issue:

technical and political. Tradeoffs must be

made between a number of technical criteria:

1) finding geographically and meteorologically

suitable areas; 2) finding sparsely populated

areas; 3) keeping down the cost of power transmission lines and transportation to the construction site; 4) siting as close to the Equator

as possible (for GEO systems) so as to keep the

north-south dimension of the receiver reasonably small; 5) coordinating receiver sites

with utility grids and the regional need for

electricity; 6) the cost of land; and 7) ensuring

that the receivers are sited away from critical

and sensitive facilities that might suffer from

electromagnetic interference from SPS, e.g.,

military, communications, and nuclear power

installations. In addition, for the reference and

SOLARES systems, as presently designed, large

contiguous plots of land would have to be

located and totally dedicated to one use (table

4). The laser options might require less land

area per site, but a greater number of sites to

deliver the comparable amount of power.

It is clear that the choice of frequency,

ionospheric heating limits, and radiation

standards could have an impact on the land requirements. Further study is needed to understand fully the environmental and economic

impacts of a receiver system on candidate sites

and to determine if enough sites can be

located to satisfy the technical requirements.

In addition the plausibility of multiple uses

(e.g., agriculture or aquiculture), offshore

siting (especially for land-scarce areas such as
Ch. 3—Issues and Findings ● 4 7

Table 4.—SPS Systems Land Use

Number of sites Total land area(km2)

SPS system k m

2

/site km2

/1,OOOMW for 300,000 MW for 300,000 MW m

2

/MW-yr

Reference . . . . . . . . . . . 174 35.0 60 10,400 1,233b

Solid statec . . . . . . . . . . . 50 33.0 180 9,000 1,163b

Laser Id. . . . . . . . . . . . . . . 0 1.2 600 360 42-51e

Laser lId. . . . . . . . . . . . . . 40 80.0 600 24,000 2,819-3,382e

Mirror I . . . . . . . . . . . . . . . 1,000 - 2 9 2,200 261-313e

Mirror Ilf. . . . . . . . . . . . . . 100 9.6 30 2,880 338-406e

For comparison

Washington. . . . . . . . . . . 174.0

New York City. . . . . . . . . 950.0

Chicago. . . . . . . . . . . . . . 518.0

aR~~t~nna at 34. latitude ~over~ a 117 km, e(lipitical area, Mi~r~~ave power density at edge of rectenna is 1.(J mw/cm2, If an exclusion boundary is set at 0.1 mW/Cm2,

then the total land per site is approximately 174 km2

. J. B. Blackburn, Sate//ire Power System (SPS) Mapping of Exc/usion Areas for Rectenna Sites, DOE/NASA Report

HCP/R-4024-10, October 1978 does not include land for mining or fuel transport.

bThe values for the reference and solid-state designs assume a 30-year lifetime and a caPacitY factor of 0.9

cThe solid-state sandwich design is described in G. M. Hanley et al., “Satellite Power Systems (SPS) Concept Definition Study, ” First Performance Review, Rockwell international Report No. SSD79-0163, NASA MSFC Contract NAS8-32475, October 10, 1979.

dLaser 1 and Laser II are two laser systems considered by DOE Both deliver the same amount of power but the beam of Laser I is more narrow (and hence rllore intenSe)

than that of Laser Il. See C. Bain, Potential of Laser for SPS Power Transmission, October 1978, Department of Energy, HCPIR-4024-07.

eThe values for the laser and mirror systems assume a 30-year lifetime and CapaCitY factors of 0.75-0.9.

fMirror I system parameters are defined by SOLARES “baseline system” and Mirror II system for low (1 ,100 km) orbit

gThe SOLARES baseline system is designed to deliver 81O GW to 6 sites; 2 SOLARES basellne sites actually provide 270 GW.

the Northeast United States, Europe, and

Japan) and possible receiver siting in other nations, with their particular environmental constraints, need to be explored.

The regional political problems may be

more severe than the technical ones, especially in light of past controversies over the siting

of powerplants, powerlines, and military radar

and other facilities. While the construction

and operation of receivers might be welcomed

by some communities on the basis of economic benefit, others might oppose nearby receiver siting for a number of reasons, including: environmental, health and safety

risks; fear that the receiver would be a target

for nuclear attack; fear of decreased land

values; preference for an alternate use of the

land; objection to the receiver’s visibility; and

for rural Americans, resistance to the intrusion

of urban life.

It is essential that many of the environmental uncertainties be diminished and that the

effects are shown to be, at worst, comparable

to those of alternate inexhaustible energy

sources, before commitment to the development of SPS because:

1. environmental effects may be identified

for which there are no acceptable mitiga2,

If

tion strategies or for which mitigation is

too costly to make SPS competitive; and

they have a great bearing on the system

design, e.g., choice of frequency, power

level and distribution may be determined

by the results of bioeffect and atmospheric studies and these may in turn control hardware design, cost, and land use.

an SPS program is pursued, the assessment

of environmental risks should receive the

highest research priority. Some studies such as

bioeffects research may require substantial

time to complete; the resolution of environmental uncertainties could affect the development schedule of SPS. Much of the environmental research needed in the assessment of

SPS is applicable to other studies and would be

valuable whether or not an SPS program is

undertaken. Conversely, many of the environmental questions associated with SPS are

also being addressed in other “generic” research programs such as those investigating

microwave bioeffects and upper atmosphere

physics. The delineation of which environmental risks are most important would, to a large

extent, depend on the specific design concepts

that showed the greatest promise.
48 • Solar Power Satellites

ELECTROMAGNETIC COMPATIBILITY

How would SPS affect other users of the

electromagnetic spectrum?*

Whether SPS were to be eventually deployed as a microwave, laser, or mirror system,

it would affect some portion of the electromagnetic spectrum. Other users of the spectrum would be concerned about the nature of

potential detrimental effects, whether they are

amenable to amelioration and, if so, what the

costs would be. A microwave system would be

the most problematic because communications of all sorts share this general portion of

the spectrum. In addition, a wide range of

other electronic devices (e. g., sensors, computers) are susceptible to microwave interference.

The Public

Deploying SPS would markedly change the

visual appearance of the night sky. A set of

reference system satellites equally spaced

along the Equator would appear as a set of

bright stationary “stars” whose total effect for

observers on longitudes near the middle of the

set and for all latitudes along these longitude

lines would equal the Moon at about quarter

phase. Nonstationary satellites such as an LEO

deployed laser or mirror system would create

the effect of bright moving “stars.” The effect

of such satelIites on the night sky has not been

calculated. However, it could be expected to

equal the overall effect of the 60-satellite set

of reference satelIites.

Some observers might well enjoy the sight of

manmade “stars” added to the night sky.

Many, especially those in countries who failed

to benefit from the generated power, might

strongly resent the intrusion on the celestial

landscape.

Space Communications

All artificial Earth satellites use some portion of the electromagnetic spectrum for com-

‘See ch. 8

munication. Some also use the spectrum for

remote sensing. All would be affected in some

way by SPS.

Geosynchronous Satellites.– These would be

most strongly affected by the microwave systems. They could be expected to experience

microwave interference from noise at the fundamental SPS frequency (e.g., 2.45 Ghz for the

reference design), spurious emission in nearby

bands, harmonics of the fundamental SPS frequency, and from so-called intermodulation

products. All radio frequency transmitters generate such noise and receivers are designed to

filter out unwanted effects. However, the

magnitude of the power level at the central

frequency and in harmonic frequencies for a

microwave SPS is so great that the possibility

of degrading the performance of satellite

receivers and transmitters from these spurious

effects is high.

In addition to the direct effects from microwave power transmissions, geosynchronous

satellites could also experience “multipath interference” from geostationary power satellites due to their sheer size. In this effect, microwave signals traveling in a straight line between CEO communications satellites would

experience interference from the same signal

reflected from the surface of the power

satelIite.

The sum of all these effects would result in a

limit on the distance that a geosynchronous

satellite must have from the SPS in order to

operate effectively. The minimum necessary

spacing would depend directly on the physical

design of the satellite, the wave length at

which it operated, and the type of transmission

device used (i.e., klystron, magnetron, solidstate device).

Since a microwave SPS would have to share

the limited resource of the geostationary orbit

with other satellites, the value of the minimum

spacing has emerged as one of the most critical issues facing a geostationary SPS. However, in the absence of a specific design, it is

impossible to characterize the exact form and
Ch. 3—Issues and Findings ● 49

nature of the interference. Additional information is essential to calculate the minimum required spacing. In addition, even if the design

parameters were known accurately, the theory

of phased arrays is insufficiently developed today to predict the minimum distance. Estimates of the minimum necessary spacing

range from 1/2 0 to 10. The lower limit would

probably be acceptable. However, a minimum

spacing much greater than 10 would result in

too few available geostationary slots to allow

both types of users to share the orbit unless

many communications functions could be accommodated on a few large space platforms.

At present, some 80 satellites share the

geostationary orbit worldwide, and by 1990

that number is expected to increase significantly (fig. 6). Even though improvements in

technology will lead to a reduction in the total

number of satellites necessary to carry the

same volume of communications services,

total service is expected to rise dramatically.

Figure 6.—The Number of Geosynchronous

Satellites as a Function of Time

1980 1985 1970 1975 1980 1985 1990

Year

SOURCE: W. L. Morgan, Comsat Technical Review, 10 vol. 1,1980.

At present the minimum spacing for domestic

geostationary satellites is 40 in the 4/6 GHz

band and 30 in the 12/14 HGz band. At these

spacings, a maximum of 90 4/6 GHz band satellites and 120 12/14 GHz band satellites could

theoretically coexist at geostationary altitudes, in the absence of SPS. Current research

activity in the 20/30 GHz band is likely to lead

to much greater capacity and smaller spacings

for that band by the time an SPS might be

deployed. But even with these and other unpredictable advances in communications technology in space and on the ground, competition for geostationary orbit slots is likely to be

high.

The laser and mirror systems in low-Earth orbit are unlikely to interfere with geosynchronous satellites except in the relatively improbable event that one of the mirrors passes precisely between the geosynchronous satellite

and its ground station, and even that interruption would be for so short a time as to pose no

serious problem.

Other Satellites. – In addition to geosynchronous satellites operating at the same altitude

as the CEO SPS, there are numerous military

and civilian satellites in various low-Earth orbits that might pass through an SPS microwave

beam. Such satellites could in principle protect themselves from adverse interference

from the SPS beam by shutting down uplink

communications for that period, and improving shielding for data and attitude sensors,

computer modules, and control functions.

Whether this action would be feasible depends

on the particular mission the satelIite is to perform. For some remote sensing satellites, a

shutdown could mean loss of significant data.

It would not be feasible for the SPS to shut

down for the few seconds of satellite passage.

It might also be possible for many satellites to

fIy orbits that will not intersect the SPS beam.

The laser and mirror systems might interfere

with nongeosynchronous satellites by causing

reflected sunlight to blind their optical sensors

or by passing through communications beams.

Of the two systems, the mirror system would
50 ● Solar Power Satellites

cause the most problems because of the size

of the mirrors and their orbital speed. To date,

no one has calculated the possible adverse effects due to this cause.

Deep Space Communications. – Because

deep space probes generally travel in the plane

of the solar system (known as the ecliptic),

they would be especially affected by a geostationary microwave SPS. A microwave SPS

would effectively prevent ground communication with the probe when the latter happens to

lie near the part of the ecliptic that crosses the

Equator. This interference is especially serious

for deep space vehicles because it is essential

to be able to communicate with them at any

time for the purposes of orbit control and for

timely retrieval of stored data.

It would be possible to avoid such interference by establishing a communications

base for deep space probes in orbit. As we

penetrate deeper into space, this may be advisable for other reasons. If not, such a communications station would effectively add to

the cost of the SPS.

Terrestrial Communications and

Electronic Systems

Both civilian and military terrestrial communications, radar, sensors, and computer

components would suffer from a number of

possible effects of a microwave beam. Direct

interference can occur from the central frequency or the harmonics. In addition, scattered and reflected radiation at these frequencies from the rectenna, and rectenna emissions

could cause additional interference problems

for terrestrial receivers. At the very least,

rectennas would have to be located far enough

from critical sites such as airports, nuclear

powerplants, and military bases to render

potential interference as small as possible. In

addition, equipment would have to be redesigned to permit far better rejection of unwanted signals than is now necessary. This appears to be feasible given enough time and

funds for the electronics industry to respond.

Effect on Terrestrial Astronomy

and Aeronomy

None of the proposed SPS systems benefit

astronomical research except insofar as they

would indirectly provide a transportation

system and construction capabilities for placing large astronomical facilities in space. The

detrimental effects would vary depending on

the system chosen. The impacts of a microwave system are likely to be severe for both

optical and radio astronomy. An infrared laser

system is likely to have fewer detrimental effects on both forms of astronomy, and the mirror system would have its most serious effect

on optical astronomy.

Optical Astronomy.– Diffuse reflections

from the reference system satellites would

cause each to be as bright as the brightest

phase of the planet Venus, and produce a diffuse halo of light around it. Because the

satellites appear to remain stationary along

the celestial Equator, a system of 15 to 60

satellites would meld together to block observation of very faint objects along and near the

Equator for telescopes located on Earth between the longitude limits of the satellites (fig.

7). Some major non-U. S. telescopes would be

affected as well. Telescopes in orbit, such as

the U.S. Space Telescope scheduled to be

launched in 1984, will travel in nonequatorial

orbits and therefore would not be affected

significantly by a reference SPS except to

require increased pointing and control complexity on the Space Telescope.

The effect of diffuse reflections from an

LEO-based laser SPS could be expected to be

much less of a problem for observations of objects near the Equator because the laser portion of the satellite system would be constantly in motion. Thus, no part of the sky would be

permanently blocked from view. The relay

satellites located in geostationary orbit would

subtend a very small angle as seen from the

surface of the Earth. Though they would be

visible as small points of light, they would be

considerably fainter than the geostationary
Ch. 3—Issues and Findings ● 51

Figure 7.—The SPS Brightness Profile

–40° –20° 0° 200 40“ 60“ 80“

Declination

Note: This figure shows the predicted brightness of the sky as a result of a

60-satellite SPS system along the meridian at local midnight for Kitt Peak

National Observatory at the vernal equinox. The calculation of this profile

is based on an assumed 4 percent diffuse albedo

SOURCE: Workshop on SPS Effects on Optical and Radio Astronomy,

DOE/Conf 7905143, P. A. Ekstron and G M Stokes (eds.).

satellites of the reference system and would

not interfere with optical observations. However, large moving satellites would present optical astronomy with another observational

obstacle. Scattered Iight from them would vary

in intensity as the satellite passes near a

celestial object of interest, making calibration

of the nearby background light very difficult.

The laser satellite would interfere with infrared

astronomy studies involving wavelengths near

the transmission wavelength of the beam. Photometry and spectrometry experiments would

be severely compromised during any brief orbital period when the relay satellite passed

within a few degrees of an observing telescope.

The mirror system, which would involve a

number of large, highly reflective moving mirrors in low Earth orbit, would have very serious

effects on optical astronomy. While the

precise effect has not been calculated, it

would render a large area (a circle of radius

150 km) around the ground stations unacceptable for telescopic viewing. Because of diffuse

reflections from the atmospheric dust and

aerosols that are up to 3 km above the ground

station, the individual mirrors would create

moving patches of diffuse light that would

completely disrupt the observation of faint objects that lie in the direction of the satellite

paths. Thus, astronomers would need to remain outside a 30()-km diameter circle surrounding the site in order to avoid this

problem.

Radio Astronomy. – Radio astronomy would

suffer two major adverse affects from microwave systems: 1 ) electromagnetic interference

from the main SPS beam, from harmonics,

from scattered or reflected SPS signals, and

from reradiated energy from rectennas; and 2)

additional sources of thermal noise radiation

in the sky that have the effect of lowering the

signal-to-noise ratio of the radio receivers.

Studies by terrestrial radiotelescopes of faint

radio objects near the Equator would be impossible. Neither the laser nor the mirror

systems would contribute to the first effect;

however, they would raise the effective

temperature of the sky background. Low-level

measurements such as scientists now routinely

conduct to measure the amount of background radiation from the primordial explosion of the universe would thus be impossible

from terrestrial bases. Thermal microwave

radiation from the satellites would exceed

present standards for radio interference at

nearly all wavelengths.

Space basing of radio telescopes, especially

on the far side of the Moon, would eliminate

the impact of SPS and other terrestrial sources

of electromagnetic interference. However,

such proposals, though attractive from the

standpoint of potential interference, are

unlikely to be attractive to astronomers for

many decades because of their high cost and

the relative inaccessibility of the equipment.

Optical Aeronomy. –Much of our knowledge

of the upper atmosphere is gained by nighttime observations of faint, diffuse light. Some

of the observations that are made today must

be carried out in the dark of the Moon. The

presence of satellites equal in brightness to a

quarter Moon would effectively end some

studies of the faint airglow and aurora. Other

observations would be severely limited in

scope.
52 . SoLar Power Satellites

SPACE PROGRAM

How would development of the SPS affect

our civilian space program?*

If pursued, an SPS program would be the

largest and most ambitious space program

ever undertaken. SPS development could provide: 1 ) new capabilities for future space ventures; 2) spinoffs for civilian and military use,

in space as well as other areas; 3) a political

and programmatic focus for the civilian space

program; and 4) potential furtherance of U.S.

domestic and foreign policy goals.

An SPS program would require the development of a high-capacity space transportation

system, the construction of large space structures, and perhaps the deployment of manned

space bases. I n addition, an extensive industrial infrastructure would be needed to support

these activities. The hardware, knowledge, and

facilities generated by such a program would

significantly increase our overall space capabilities and lay the groundwork for future industrialization, mining and, perhaps, the colonization of space.

Direct technological spinoffs can be expected in the development of improved large

space platforms, energy transmission devices,

ground illuminating systems, high-efficiency

solar celIs, and Iife-support systems.

Conversely, SPS development will benefit

from prior developments in space technology,

most notably in space transportation and

systems for automated construction of space

structures.

An important consideration is the extent to

which an SPS program wouId serve as the

focus and driving-force for the space program

as a whole. In the 1960’s, the U.S. civilian effort was centered on Apollo; in the 1970’s on

the Space Shuttle. However, in 1978, the Carter

*For extended discussion see ch. 6

administration stated that: “it is neither feasible nor necessary at this time to commit the

United States to a high-challenge space engineering initiative comparable to Apollo. ” In

the absence of a long-term goal such as SPS,

some have predicted that future space efforts

wouId lag, or become overwhelmingly military

in nature. On the other hand, there is concern

that an SPS commitment would draw resources from or otherwise interfere with other

space activities, leading to an unbalanced effort. In addition, for SPS as well as other less

expensive programs, the annual appropriations

procedure for NASA often results in budgetary

and programmatic uncertainty; development

of SPS would require long-term financial planning and long-term commitment to the project.

In addition to its use as a source of electrical

power, the SPS should be judged by whether it

is in accord with national interests as reflected

in national space policy. The NASA Act of

1958 (as amended), states that space activities

should be for peaceful purposes, and can be

undertaken in cooperation with other countries, to further the “general welfare and

security” of the United States. In 1978 the

Carter administration, in its October “Fact

Sheet on U.S. Civil Space Policy,” reaffirmed

these goals while emphasizing the practical

and commercial benefits of the civil space program. A civilian-run SPS program open to international participation would further current

space policy goals.

Involvement by NASA in SPS operation

might require a change of NASA’s current

charter, which restricts the direct operation of

commercial ventures. Currently, DOE has

prime responsibility for solar energy research,

while NASA is responsible for the U.S. civilian

space program. An SPS program would require

extensive cooperation between the two agencies; if this caused difficulties, a separate

agency or some other organizational alternative might prove preferable.
Chapter 4

POLICY OPTIONS
Chapter 4

POLICY OPTIONS

Because the solar power satellite (SPS) is a

new energy concept, much of this assessment

has Ied across previously uncharted territory.

SPS has potential for supplying a portion of

U.S. electrical needs, but current knowledge

about SPS, whether technical, environmental,

or sociopolitical is still too tentative or uncertain to decide whether SPS would be a wise investment of the Nation’s resources. Further

research and study, based on the findings of

this and other assessments, ’ 2 would be needed

in order to formulate such a decision properly.

The kind and pace of a research program, if

one is to be conducted, will be determined by

perceptions of when development decisions

need to be made.

Decisions about SPS development involve

an important tradeoff. I n time, more can be

learned about the context within which SPS

would operate. Furthermore, in view of this

study’s analysis of future U.S. electricity demand and the availability of alternate energy

sources (see ch. 6), domestic need is not likely

to be high enough for SPS before 2015-25.

Therefore, development and deployment decisions do not have to be made before the

1990’s. However, action should be taken in a

timely manner. Since the development of a

major energy and space system may take more

than 20 years, a decision about whether to

develop SPS will probably need to be made

before the end of the century. The development of SPS may need to be started as early as

1990, if high-growth projections for electricity

seem plausible at the time. If an SPS development program is eventually initiated, the Nation must also decide whether it wishes to pursue SPS as a unilateral or as an international

venture. The tasks before the United States in

this decade are to determine how much and

what kinds of information are needed in order

to make a sound decision sometime in the next

‘Program Assessment Report Statement of Findings, SPS Con -

cept Development and Evaluation Program, DO E/E R-0085,

November 1980.

‘National Research Council Report of the Committee on Satellite Power Systems, June 1981

decade. The Nation must also decide when to

proceed with a research program and at what

pace.

Figure 8 represents a series of possible decision points for SPS. If research on SPS finds no

impediments to continued pursuit of SPS, the

first in the series of development decisions

couId occur sometime between 1990 and 2000.

By that time, the factors that relate to energy

demand and supply and space transportation

will be much clearer than they are today. The

United States will have had about 10 years of

experience with the space shuttle and with initial testing of space platform components.

Planning and perhaps testing will have begun

for a second-generation space transportation

system. The resuIts of the Nation’s long-term

energy conservation efforts will be felt and

assessed, and electricity demand projections

for 2000 and afterwards will be better defined

than currently possible. Further, a decision

about the breeder may have been made and

the potential of the fusion, energy storage, and

terrestrial solar technologies may be more certain.

The results of continued tracking of the international, institutional, and public opinion

factors relevant to SPS will also contribute to

the decision. In particular, the international

community’s future energy needs and supply

potential will be better known, as well as its

willingness to cooperate in a multinational

development program.

Finally, the results of research related to SPS

wilI be available and can be used to support or

reject a decision whether to proceed with SPS

development. Some of the needed research is

generic in nature, and will be done in other

programs whether or not SPS is developed.

Among others, these include most of the National Aeronautics and Space Administration’s

(NASA) activities in space transportation,

space structures, photovoltaics, materials and

humans in space, as well as the Department of

Defense’s (DOD) and the Department of

Energy’s (DOE) laser programs. To some extent

55
56 ● Solar Power Satellites

Figure 8.—SPS Program Phases and Decision Points

Program level

(funding)

Demonstration

Systems

engineering,

space testing

Research,

component

testing

CDEP

No program

. . . . . .

DP 1 DP 2 DP 3 DP 4 Time

● DP 1 ● DP 2 ● DP 3 ● DP 4

— No program —

— Research —.

SOURCE: Office of Technology Assessment.

they also include work done in the

No program — No program —

Research — Research —

Initiate development — Continue systems —

engineering

— Demonstration ——

No SPS

Research

Systems

engineering

New demonstration

Deployment

terrestrial eventually require a research program spephotovoltaics (DOE) and microwave bioeffects cifically funded for SPS.

(the Food and Drug Administration, the Environmental Protection Agency, etc.) pro- In order to make an informed decision about

grams. However, many needs are directly the SPS, information about three different

related to SPS technology and therefore will types of factors will be needed:
Ch. 4—Policy Options ● 57

1. Contextual, independent factors. These

are factors that are independent of SPS

but which will markedly affect the need

for SPS or the ability to conduct the project:

● Future U.S. and global electricity demand. If demand is relatively low, the

need for a new, capital-intensive energy

system will be low as well. If future demand is very high, there could be a

commensurate need for SPS. Conservation, increased end-use efficiencies, and

the expansion of dispersed electrical

generation could all affect overall demand for centralized electricity.

● Cost, kind, and availability of alternative electricity sources. If other potential future electric energy sources

turn out to be more expensive than a

projected SPS, then SPS may be desirable even if electricity demand is relatively low. On the other hand, the development of other technologies might

preclude the need for SPS. The status of

breeder and fusion technologies, the

cost of terrestrial solar and the advisability of expanding the use of coal

will all affect the need for SPS.

● U.S. and global space capabilities. A

rapidly expanding space program with

extensive experience and capabilities

would make an SPS program much

more feasible than would a low-level

program. The experience with the shuttle and other space vehicles will shed

light on space transportation capabilities and costs.

Although an SPS research program is not

likely to be affected by these factors, they will

have a great effect on an SPS development

decision. Each of the factors needs to be

tracked, studied, and continually reevaluated

for its impact on an SPS decision. Projections

of these factors 10 to 20 years in the future will

have to be made as well, and amended as more

information becomes available. Because these

factors are of universal interest, such studies

need not be funded by a specific SPS program;

they will be investigated by other energy and

space programs.

Sometime in the next decade, the contextual

framework for the future of SPS may be known

well enough to make an informed decision

about the need for SPS. As time goes on, a narrowing of future projections will occur and

knowledge of these factors will be integrated

into the overall decision about SPS.

2. Contextual, semi-independent factors.

These are the factors that arise largely

from the public perceptions and international and institutional framework of SPS.

Though they are markedly diverse in content, they have the unifying feature that

they will each affect an SPS research program only slightly but an SPS development program rather strongly. They will

need to be tracked, studied, and evaluated as any SPS research program progresses. They also possess the characteristic that there is no point at which one

can say that enough is known about them.

Rather, a development decision must take

them into account as factors that must be

considered in Iight of what is known about

them at the time.

●

●

International interest and involvement

in SPS. The worldwide community will

be interested in SPS for its potential to

provide energy. They will also be concerned about the effects it may have on

the use of the geostationary orbit, military and national prestige implications,

how it may affect communications, and

how it may affect the appearance and

use of the night sky. They may also be

interested in joining with the United

States in multinational development of

SPS. Hence, it will also be important to

explore possible modes and means of

international cooperation.

Institutional framework. A main concern of any SPS program would be to

continue to study the institutional

structures that now exist in the utilities

industry, the financial community, and

Government, and to identify the major

factors that could influence the course

of SPS development and affect its

feasibility.

83-316 0 - 81 - 5
58 ● Solar Power Satellites

● Public opinion issues Public perceptions and public involvement are important components of any publicly

funded program. Dissemination of information and sharing of research

results would be essential to the SPS

program, even in the research phase. It

would also be important to continue to

solicit responses from segments of the

public that would be especially affected, either positively or negatively,

by SPS development.

3.Technical factors specific to SPS. Knowledge about these factors can be gathered

or generated by deliberate effort. Answers

to specific questions in this group will

have an immediate effect on SPS development decisions. The kind, quantity, and

quality of the information as well as the

time at which it can be available are partly dependent on the level of funding. Four

general categories of this sort of information are evident:

● Environment and human health:

— microwave and laser bioeffects,

–high energy particle and ionizing radiation effects on humans in space,

— ionospheric effects due to microwave transmission,

– land-use impacts,

—offshore rectenna environmental effects,

– launch vehicle exhaust effects on atmosphere, and

—weather modification from mirror

systems.

● General system studies:

—alternate systems (identify which

areas need further research, and possible testing of components),

— component and system costs, and

—comparison of alternate systems.

● Component testing and evacuation:

–Klystrons/magnetrons/solid-state devices,

– high-powered, continuous-wave lasers (EDL, solar pumped, FE L),

— SIip ring designs,

–deployable, large-area, lightweight

space structures,

— space charge effects, and

– photovoltaic design and testing.

● Space construction and space transportation:

— evaluate best transportation scheme

for demonstration and

— evaluate best construction scheme.

information from all three sorts of factors

will set the framework and determine the appropriate time for development decisions. It is

important to emphasize that a decision not to

develop SPS depends on the same information

as a decision to proceed with SPS. If further

research finds no major technological impediment to proceeding with SPS and the combination of supply alternatives and demand needs

indicate that it would be prudent to proceed

with the next stage, the program could enter

the engineering verification phase where various systems are tested and a demonstration

system chosen. This would set the stage for the

next decision point.

[f it were possible to make a decision to proceed with the project early in the process (i. e.,

during the research phase) the various phases

could overlap considerably. For instance, the

early stages of demonstration could begin

before the engineering verification phase is

entirely complete. Some economic benefits

might accrue from such a procedure. However,

because of the very high front-end costs for

SPS, any proposal to proceed with development will need to be scrutinized very carefully

to be sure it is cost effective. That will

necessitate more time and study in the verification stage than might be true for a less

costly technology, making it less likely that the

various phases will overlap.

SPS research could proceed at different

rates and along different lines, depending on

the level of funding that is made available. The

following presents two different policy options. One is characterized by zero funding for

specific SPS research; the other by a sliding

scale of funding. They do not exclude one

another, i.e., pursuing one option today would

not necessariIy exclude changing to a different

option as time proceeds and information
Ch. 4—Policy Options ● 5 9

grows. For example, it could be considered

prudent to begin with no specific funding for

SPS and proceed to allocate a few million

dollars per year after a few years. Conversely,

a vigorous funding pace may produce results

quickly enough so that from the standpoint of

those factors that are amenable to research, a

development decision could be made before

1990. But because the independent factors are

unlikely to be known well enough before 199o,

research funding might then be reduced to a

lower level to keep the program going pending

a decision based on the independent factors.

Option A:

No specific funding for an SPS program.

Although it would be nearly impossible to

pursue an SPS program without specifically

allocating funding for it, this option would not

necessarily mean terminating all interest in

SPS. A zero level option could be followed by

designating an agency (e.g., NASA or DOE) to

track generic research that is applicable to

SPS, as well as monitoring and coordinating international interest in SPS. One possibility is to

set up a high-level advisory committee to serve

this latter function. As in the other option,

periodic reevaluation of the potential of SPS

would also be needed, in this case to decide

whether specific funding should be instituted

or the program terminated altogether.

The rationale behind option A is to keep SPS

alive as part of our arsenal of possible energy

supply options without making a serious commitment at this time. It has the advantages

that the risk of premature funding is greatly

reduced, as well as the upfront costs. The

longer the country can wait before funding a

program directed towards SPS research, the

more likely it is that other programs will have

generated helpful data for SPS.

On the other hand, there is little margin for

error in such an approach. If, under option A,

inadequate information is generated, the SPS

option might be neglected or foreclosed at a

time of future decision; or, if the independent

factors indicate a strong need for SPS, then an

expensive crash program of research to resolve

the questions specific to SPS may be necessary. in addition, appropriating no specific

funding for SPS carries with it the risk of

discouraging future international cooperation,

or of allowing other countries to take the lead

in SPS development. A final problem with option A is that the agency designated to track

SPS may find it very difficult to allocate its

financial resources for SPS without some specific allocation in its budget (even though

small).

What could be learned from such an option?

Other Federal and non-Federal programs are

currently exploring issues that are related to

SPS development. By tracking this generic research, information of great value to the development decision could be gathered and

analyzed.

●

●

●

●

Microwave bioeffects.The proliferation of

microwave devices at various frequencies

makes research into this important area

mandatory whether there is an SPS program

or not. FDA, EPA, and DOD are studying

microwave bioeffects.

Photovoltaics DOE maintains a strong terrestrial photovoltaics program. Together

with private industry and university projects,

this program is studying some aspects of

photovoltaics that are of great interest to

SPS. However, because terrestrial photovoltaic systems have vastly different needs and

constraints than space photovoltaic systems, additional research would probably be

needed for SPS.

Space-related activities. NASA, DOD, and

the European Space Agency (ESA) are pursuing programs in space transportation, space

structures, humans in space, and space photovoltaics by designing and building the

shuttle, advanced expendable launch vehicles, space lab, a 25 kW space power supply,

etc.

Laser programs. High-powered, continuouswave lasers are currently in an early stage of

development. Some of the research on high

energy pulsed lasers being pursued by the

DOD for weapons applications and by DOE

for fusion studies will be relevant to the SPS

laser concept. Universities and other research labs are studying high-powered, con-
60 • Solar Power Satellites

tinuous-wave lasers. This research would be

directly applicable to a laser SPS.

● Alternateve energy sources. The resuIts of

R&D, prototype construction, and operation

of other electricity sources, including solar

thermal, breeders, ocean thermal energy

conversion, and fusion, will be of great importance in determining future need for SPS.

However, many issues directly pertinent to

SPS cannot be answered by generic research

programs. For instance, while microwave bioeffects experiments are being performed in

generic research programs, the number of

studies on low-level, long-term exposure to SPS

frequency microwaves is small.

mation directly relevant to SPS,

SPS funding will be needed.

Option B:

Funding of $5 million to $30

year.

To gain inforsome specific

million per

This option is designed to gather the necessary information before a development decision is needed. It minimizes the risks of not

gaining the sufficient and timely information

necessary for a rational decision.

This program would, like option A, make as

much use as possible of generic research. It

would extend the generic research into areas

specific to SPS by making small amounts of

funding available for expanding generic programs essential to the SPS development decision. It would also initiate research that is not

being done in generic programs and explore

ways in which to pursue some of this research

jointly with other nations. In addition, it would

track and study the various semi-independent

factors (international, institutional, and public

opinion) which would also have a profound effect on SPS decisions. It would actively seek

and encourage international cooperation in

SPS research.

Table 5 summarizes the most important research and study needs and gives a very rough

estimate of what it would cost to do each item.

The starred items are ones that could be pursued in the context of a few million dollars of

funding per year. The most critical issues relate to the environmental and health area,

since they are the most important in determining the feasibility of SPS. However, they could

also take the longest to resolve. Some component testing and studies of alternative systems

could receive high priority. The amount of

funding which would be made available would

depend on an evaluation of previous research

findings and the state of projected supply and

demand for electricity in the 21st century.

It may be prudent to start at a low level of

funding and later accelerate research that is

specific to SPS as well as make greater funding

available for SPS related generic studies.

Another possibility is to actively solicit funding for projects of joint international-U. S. interest, perhaps by offering to match foreign

funding for research projects undertaken outside the United States, but which are of interest to U.S. planners. An accelerated research program ($30 million per year) could include some component testing in space as welI

as at the Earth’s surface. It could also include

at least one shuttle mission (post 1985) and

some space-related experiments on other shuttle flights. It would seek to answer the major

environmental and health and safety questions

before 1990 and also conduct extensive systems studies. If these concerns are seen to pose

no impediments, accelerated funding would

provide the quickest way of entering a development phase.

Making funds available for SPS-specific research should ensure that enough information

is eventually available in order to make a rational development decision. This approach

also has the advantage that it could provide

for extensive international cooperation early

in the research phase before seeking more extensive financial and managerial cooperation

in any subsequent development or construction phase. This would spread the decision to

proceed or drop SPS development to other

countries as well.

However, a higher level of spending ($30

million or so per year), here and abroad, would

make it more likely that an entrenched SPS

constituency would form, giving the program

momentum and making it harder to stop; more

information may not make a program easier to
Ch. 4—Policy Options ● 61

terminate. Under such conditions, our under- transmitting power will develop too early and

standing of SPS technology may outstrip our close out SPS options which are uncertain in

knowledge of future electricity demand. It is the near term but which may have more longalso possible that support for a given mode of run potential.

Table 5.—Summary of Research and Study Needs

Expansion of generic research Estimated Estimated

Research/study area to SPS-specific needs cost SPS-dedicated projects costs

Environmental and human health

—

● Microwave bioeffects $5 million to Quantify SPS risks. $2 million

$10 million Epidemiological

studies.

● Laboratory studies of long-term

exposure to low-level

microwaves at 2.45 GHz.

Determine possible nonthermal

effects, and dose-response

relationships, establish

extrapolation laws.

● Ionospheric studies ● Study of ionospheric scaling —

laws.

microwave

● Atmospheric studies ● Track and augment observations of the atmospheric

effects of launch effluents

from the shuttle, other expendable launch vehicles and

high altitude rockets.

Refine and test ground

cloud models. Study

meteorological and air

quality impacts.

Determine the nature and

effect of ionospheric depletion, especially in

lower ionosphere. Utilize

other rocket launches and

observe the effects on

representative telecommunication systems.

● Ionizing radiation ● Track and augment existing

studies of effects of ionizing

radiation on humans.

Study shielding methods.

● Space ● Track and augment existing

programs examining the risks

and protection measures for

humans in space.

● Electromagnetic ● Study potential electromaginterference netic interference and design

mitigating techniques. Improve

theory of phased array.

$2 million

$0.3 million to

$5 million

$0.5 million

$2 million to

$3 million

$0.2 million

$2 million

‘Ionospheric equivalent $10 million

heating. Upgrade Arecibo

facility. Study SPS

equivalent heating in

upper atmosphere. Test

scaling laws and effects

on representative telecommunication systems.

● Experiments to test $1 million

effects of SPS

effluents on magnetosphere and to

increase understanding of

that region.

Quantify and study SPS

effects on the hydrogen

cycle, and formation of

noctilucent clouds.

● Study effect on local

climate of SOLARES-type

system using an array of

ground heaters or a solar

pond.

*Studies of possible

weather modification,

beam scattering

and spreading.

Identify transportation

scenarios that

minimize impacts.

● Investigate antenna $1 million

patterns of klystron,

magnetron, solidstate devices (see below),

their noise levels, and

out-of-band harmonics.
62 ● Solar Power Satellites

Table 5.—Summary of Research and Study Needs—Continued

Expansion of generic research Estimated Estimated

Research/study area to SPS-specific needs cost SPS-dedicated projects costs

• Environmental Offshore receiver studies $0.5 million

impacts of Land use studies $2 million

receiver siting

General system studies

● Laser system

● Mirror system

● Alternative microwave

Component testing and

evaluation

● Microwave

transmission

● Continue solid-state device $3 million to

improvement, study noise, $6 million

interference problems

● Test intermediate power $2 million

magnetron, high-power klystron

● Solar thermal

conversion

. Photovoltaics ● Extend research to low mass,

thin film cells for space

● Lasers ● Improve efficiency of EDL

lasers, develop cooling mechanisms for space lasers

. Mechanical

components

● Mirro r

$1 million

$2 million

$3million to

$10 million

● Develop a “reference” $0.5 million to

laser system $1 million

*Develop a “reference” $0.5 million to

mirror system $1 million

*Develop alternative

microwave systems

*Perform a true compar- $1 million

ative study between SPS

alternatives using common technology and cost

basis.

Develop solid-state $2 million to

phased array $10 million

Study alternative micro- $.3 million to

wave devices, such as $1 million

photoklystron

● Adapt optimum $2 million

photovoltaics for SPS,

i.e., low mass, high

efficiency, radiation

resistant

● Build solar pumped $1 million to

lasers $3 million

● Laser optics $0.1 million to

(feasibility studies) $0.3 million

● Study means of $0.3 million

constructing slip ring

and rotating joint

*SOLARES mirror materials

structures

Develop prototype mirror $0.5 million

design for shuttle launch

of a single SOLARES

mirror

‘Research priority.

SOURCE: Office of Technology Assessment.
Chapter 5

ALTERNATIVE SYSTEMS FOR SPS
Contents

Page

Microwave Transmission . . . . . . . . . . . . . . 65

The Reference System.. . . . . . . . . . . . . 65

Laser Transmission.. . . . . . . . . . . . . . . . . 78

Laser Generators . . . . . . . . . . . . . . . . . . . 79

Laser Transmission . . . . . . . . . . . . . . . . 81

Laser-Power Conversion at Earth . . . . . . 82

The Laser-Based System . . . . . . . . . . . . . 82

Mirror Reflection . . . . . . . . . . . . . . . . . 86

The Mirror System. . . . . . . . . . . . . . . . . . 88

Space Transportation and Construction

Alternatives . . . . . . . . . . . . . . . . . . . 89

Transportation . . . . . . . . . . . . . , . . . . 89

Space Construction. . . . . . . . . . . . . . . . . 91

SPA Costs . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Reference System Costs . . . . . . . . . . . . 92

Alternative Systems . . . . . . . . . . . . . . . . 96

The Solid-StateSystem . . . . . . . . . . . 96

The Laser System . . . . . . . . . . . . . . . . . . 96

The Mirror System. . . . . . . . . . . . . . . . . 97

LIST OF TABLES

Table No. Page

6.

7.

8.

9.

10.

11.

12.

13.

Projections for Laser Energy Converters

in 1981-90 . . . . . . . . . . . . . . . . . . . . . . .

500 MWe Space Laser Power System. . .

Laser Power Station Specification. . . . .

SOLARES Baseline Systerm . . . . . . . .

Research— $370 Million . . . . . . . . . .

Engineering– $8 Billion . . . . . . . . . . . .

Demonstration– $23 Billion . . . . . . .

SPS lnvestment– $57.9 Billion . . . . . . .

83

85

85

88

93

93

93

94

LIST OF FIGURES

Figure No. Page

9

10

11

12

13

14

15

16

17

18

19

20.

21

22.

23.

24

25

26

Solar Power Satellite Reference

System. . . . . . . . . . . . . . . . . . . . . . . . . . 66

Satellite Power System Efficiency

Chain . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Major Reference System Program

Elements. . . . . . . . . . . . . . . . . . . . . . . . 68

The Retrodirective Concept . . . . . . . . . 69

Power Density at Rectenna as a

Function of Distance From the

Beam Centerline . . . . . . . . . . . . . . . . . . 70

Peak Power Density Levels as a

Function of Range From Rectenna . . . . 70

SPS Space Transportation Scenario . . . 73

The Solid-State Variant of the Reference

System. . . . . . . . . . . . . . . . . . . .

lndirect Optically Pumped CO/CO2

Mixing Laser . . . . . . . . . . . . . . . . .

The CATALAC Free Electron Laser

Concepts. . . . . . . . . . . . . . . . . . . . .

Optics and Beam Characteristics of

Two Types of Laser Power Transmission System (LTPS) Concepts. . .

The Laser Concept. . . . . . . , . . . . .

Components of the Laser Concept .

The Mirror Concept (SOLARES) . . .

Reference System Costs . . . . . . . . .

How Cost Could Be Allowed. . . . . .

Elements and Costs, in 1977 Dollars,

the Baseline SOLARES System . . . .

Sensitivity of the SOLARES Mirror

System to Variations in System

Parameters . . . . . . . . . . . . . . . . . . .

. . . 78

. . . 80

. . . 81

. . . 82

. . . 84

. . . 84

. . . 87

. . . 92

93

for

. . . 97

. . . 98
Chapter 5

ALTERNATIVE SYSTEMS FOR SPS

A variety of systems have been proposed for

collecting, transmitting, and converting solar

power from space. Each system has its advantages and disadvantages, its benefits and drawbacks. Each alternative system would use one

of three transmission modes — microwave,

laser, or optical reflector–to transmit power

to Earth where it is collected and converted to

electricity or some other highly useful form of

energy. Each system would use numerous subsystems to collect and convert energy in space

or on the ground. This chapter wiII characterize the alternative systems and subsystems and

discuss their potential for generating power

from space. It will also describe four representative systems that serve as the technical

basis for discussion of the environmental, institutional, and public acceptance issues in the

chapters that follow.

In order to estimate reliably and fully the

range of costs and potential technical uncertainties for a given solar power satellite (SPS)

option, it would be necessary to subject it to

the same detailed analysis that the reference

system has undergone during the last 5 years.

Unfortunately, this analysis has not been accomplished for the alternative systems. Hence,

detailed comparisons between systems will not

be possible. At this stage it is possible only to

compare the major features of each technology and note the uncertainties that should be

addressed as conceptual development of the

various alternatives continues.

MICROWAVE TRANSMISSION

Because the atmosphere is highly transparent to microwaves, they constitute an obvious

candidate for the SPS transmission mode. In

addition, microwave technology also is wellknown and is used today in a number of space

and terrestrial communications and radar applications. Microwave power transmission was

first demonstrated experimentally in 1964, ’

and tested in 1974.2 3

The Reference System4 56

The reference system was selected by the

Department of Energy/National Aeronautics

1). F Degenford, M D. Sirkis, and PV H Steir, “Ttle Reflecting

Beam Waveguide, ” I E EE Transactions 01 Microwave Theory

Technology MIT-72, July 1964, pp 445-453

‘Richard M Dickinson, “Evaluation of a Microwave HighPower Reception-Conversion Array for Wireless Power Transmission, ” Jet Propulsion Laboratory Technical Memorandum No

33-741, Sept 1, 1975

~R i chard M Dick InsOn, “Microwave Power Transmitting

Phased Array Antenna Research Project Summary Report, ” Jet

Propulsion Laboratory publication No 78-28, Dec 15, 1978

‘Department of Energy, “Satellite Power System Concept Development and Evaluation Program Reference System Report, ”

report No. DOE/E R-0023, October 1978

‘C. C. Kraft, “The Solar Power Satellite Concept, ” NASA publication No JSC-14898, July 1979

and Space Administration

basis for study. It consists

(DOE/NASA) as a

of a large planar

array of photovoltaic celIs located in the geosynchronous orbit 35,800 km above the Earth’s

Equator (fig. 9). The cells convert solar energy

into direct-current (de) electricity that is

conducted at high voltage to a phased-array

microwave transmitting antenna mounted at

one end of the photovoltaic array. Klystron

amplifiers convert the dc electricity to highvoltage radio-frequency power that is then

radiated to Earth by slotted waveguides. A

receiving antenna (rectenna) on the ground

reconverts the electromagnetic radiation into

electric current and rectifies it into dc. After

being converted to high-voltage, low alternating current (ac), the power can then be

either delivered directly to the conventional ac

grid or converted back to dc at high voltage

and delivered to a dc transmission network.

The amount of power delivered to the grid

by each reference system rectenna has been

bR O Piiand, “SPS Cost Methodology and Sensitivities, ” The

F/na/ Proceedings of the Solar Power Satellite Program Review,

DOE/NASA Conf-800491, July 1980.

65
66 ● Solar Power Satellites

Figure 9.—Solar Power Satellite Reference System

Transmitt

Solar power satellite reference system

Solar cell arr

ty

SOURCE: C. C. Kraft, “The Solar Power Satellite Concept,” NASA publication No. JSC-14898, July 1979

set at 5 gigawatts (GW)—or 5,000 megawatts

(MW). The microwave transmission frequency

was chosen to be 2.45 gigahertz (GHz). Maximum microwave power density at the center

of the rectenna (on Earth) was set at 23

milliwatts per square centimeter (mW/cm2

),

and the maximum power density at the edge of

the rectenna was set at 1 mW/cm2 (one-tenth

the current U.S. recommended occupational

limit). The reference design assumes that all

materials would be obtained from Earth, and

that the system lifetime would be 30 years with

no residual salvage value.

The area of the satellite’s photovoltaic array

would be approximately 55 square kilometers

(km2

); the diameter of the transmitting antenna

1 km. The total in-orbit mass of the complete

system, including a 25-percent contingency

factor, would be either 51,000 or 34,000 metric

tons (tonnes), depending on whether silicon or

gallium arsenide photovoltaic cells would be

used.

The system is designed to deliver baseload,

i.e., continuous 24-hour power to the electric

grid. However, some variations in delivered

power would occur. A seasonal fluctuation in

output due to the variation of the Sun’s distance from Earth would cause variations in

both incident insolation and photovoltaic cell

temperature, the latter producing a consequent change in efficiency. In addition, around

the spring and fall equinoxes the Earth’s

shadow would occult the SPS, resulting in a

short period each night for about 6 weeks at

local midnight (about 75 minutes maximum, at

the equinoxes) where no solar radiation impinges on the satellite and therefore no power

could be delivered to the grid (see ch. 9 for a

discussion of this effect).

Subsystem Description

ENERGY COLLECTION AND CONVERSION

Two photovoltaic concepts were considered

for the DOE/NASA reference system. One uses
Ch. 5—Alternative Systems for SPS . 67

Ga

71.77 GW

(Solar)

70.81 GW

Si

Figure 10.

63.18 GW

62.34 GW

-Satellite Power System Efficiency Chain

57.81 GW 11.58 GW 10.50 GW 9.46 GW

Ga

10.79 GW 10.29 GW 9.79 GW

Si

Ga 9.08 GW

8.50 GW 8.50 GW 8.18 GW 6.96 GW 6.72 GW

Si

9.08 GW

6.58 GW 5.79 GW 5.15 GW

overall efficiency = 6.970/. Ga MPTS efficiency = 63.00/.

7.06% Si

Abbreviation: “Ga” indicates the gallium-alum aluminum-arsenide option, “Si” the silicon option.

SOURCE: Department of Energy, “Satellite Power System Concept Development and Evaluation Program: Reference System Report,” DOE report No.

DOE/ER-0023, October 1978.

single crystal silicon converters that would

receive sunlight directly; the other uses

gallium-arsenide (GaAs) photovoltaic cells illuminated directly and by mirrors in a 2:1 concentration ratio.

Silicon cells, currently used in all solar

powered spacecraft, have the advantages of

an extensive manufacturing base, abundant resource materials, and lower cost per cell, as

well as an R&D program in DOE aimed at major cost reduction for terrestrial cells. However, silicon cells in space suffer degradation

from radiation effects and from high-operating

temperatures, and hence would probably require periodic annealing of the array surface

(possibly by laser or electron beam techniques)

or the development of silicon cells less affected by ionizing radiation.

Gallium-aluminum arsenide photovoltaic

cells have several advantages over silicon

cells: low mass per unit area, resistance to thermal and radiation degradation, and higher efficiency. They have the disadvantages of relatively high cost, the limited production availability of gallium, and a smaller technology

base than for silicon cells. Because of these

latter characteristics, these cells would be

used in a 2:1 concentration ratio in the reference system, trading the relatively expensive

cells for less expensive Iightweight reflectors

to concentrate sunlight on the cells.

The structure that supports the solar cells

would be an open-truss framework made of

graphite-fiber reinforced thermoplastic composite (fig. 9). Because the solar array must be

oriented toward the Sun and the transmitting

antenna toward the Earth, a massive rotary

joint is essential in order to provide the necessary mechanical coupling. Sliprings about

400 m in diameter would be used in conjunc-
68 ● Solar Power Satellites

Figure 11 .—Major Reference System Program Elements

construction

depot

Space

freighter

COTV

GEO

SOURCE: R. O. Piland, Cost Methodology and Sensitivities,” The Final Proceedings of the Solar Power Satellite Program

Review, DOE/NASA 1980.

tion with the rotary joint in order to transfer

electric power from the array to the antenna.

POWER TRANSMISSION AND DELlVERY

The power transmission and delivery system

for the reference system design is common to

both photovoltaic options. It is composed of

three major elements: the transmitting antenna, the rectenna, and the substation.

The selection of the microwave transmission

frequency was based on tradeoffs between atmospheric attenuation and interactions with

the ionosphere as well as the sizes of the

antenna and rectenna. The optimal frequencies were found to be between 1.5 and 4 GHz.

The reference frequency was selected to be

2.45 GHz, which lies in the center of the international Industrial, Scientific, and Medical

(ISM) band of 2.4 to 2.5 GHz.

The size of the antenna is determined by the

transmission frequency, the amount of heat it

is feasible to dissipate at the antenna, the

theoretical limits of ionospheric heating, and

the maximum power densities chosen at

ground level, i.e., at the rectenna.7 For the

‘Raytheon Corp., “Microwave Power Transmission System

Studies,” report No, ER75-4368, contract No NAS3-I 7835, December 1975.

reference system, these design considerations

resulted in a l-km diameter antenna. It would

be constructed of 7,220 subarrays each containing from four to thirty-six 70-kW klystron

power amplifiers connected to slotted waveguides for transmitting power to Earth. KIystrons were chosen because their technology

and operating characteristics at low power

levels are well-known. However, they require a

cooling system (probably heat pipes). Klystrons

of 70-kW continuous power rating have not

been built and tested at this frequency, so their

characteristics are not known in detail.

Each of the more than 100,000 klystrons in

the antenna must be properly adjusted or

“phased” to provide a uniform power beam

and to point it. This adjustment is especially

critical at the very high, gross power level of

the SPS beam. Were the antenna a totally rigid

array of amplifiers precisely fixed in space, the

adjustment could be accomplished once and

for all just after the antenna is fabricated in

space. However, because it would be desirable

for the antenna to be relatively flexible it

would be necessary to use an active system of

phase control, a so-called “adaptive electronic

control” in which a pilot beam, installed in the

center of the rectenna and pointed toward the
Ch. 5—Alternative Systems for SPS ● 69

satellite, establishes a phase reference or

standard clock against which the individual

klystrons compare and adjust their phases (fig.

12).8

An important safety feature inherent in this

system is that loss of the pilot beam from the

rectenna would eliminate all pointing and

phase control. Without the pilot beam, the

klystron subarrays would immediately lose

synchronization with one another and al I focus

would be lost, resulting in the spreading of the

‘William C Brown, “Solar Power Satellites Microwaves Deliver the Power, ” Spectrum, June 1979, pp 36-42.

Figure 12.—The Retrodirective Concept

In the retrodirective-array concept, a pilot beam from the

center of the rectenna establishes a phase front at the

transmitting antenna. Central logic elements in each of the

antenna’s 7,220 subarrays compare the pilot beam’s phase

front with an internal reference, or clock phase. The phase

difference is conjugated and used as a reference to control

the phase of the outgoing signal. This concept enables the

transmitted beam to be centered precisely on the rectenna

and to have a high degree of phase uniformity. If this phasecontrol system fails, the beam would automatically be

defocused, dropping the power density to 0.003 mW/cm2

,

an intensity acceptable by current standards. This feature

has been referred to as the “fail-safe” aspect of the

microwave transmission system.

SOURCE: William C. Brown, “Solar Power Satellites: Microwaves Deliver the

Power,” Spectrum, June 1979, pp. 36-42.

beam to very low power (0.003 mW/cm2). The

transmission system would therefore require

continual ground-based guidance to keep it

operating as a coherent beam. By incorporating relatively well-known anti jamming

techniques in the pilot-beam generator, deliberate or accidental diversion or misuse of

the SPS beam could be prevented.

The parameters of the microwave beam are

of critical importance in assessing the environmental impacts of the SPS. The peak

power density at the transmitting antenna is

calculated to be 21 kW/m2. By the time the

beam reached the upper atmosphere it would

have spread considerably and the intensity

reduced to 23 mW/cm2

, a power Iimit that was

set because theoretical studies suggested that

at higher power densities, nonlinear instabilities could appear in the F layer of the ionosphere (200 to 300 km) as a result of the interactions between the beam and the electrically

charged particles in this region. Recent experimental studies indicate that the limit in the

lower ionosphere might be able to be set much

higher, ’ thereby making it possible to decrease

the size of the antenna and/or rectenna significantIy.

With these design constraints, a theoretical

beam power distribution was conceived resulting in the radiation pattern at the rectenna

shown in figure 13, on which are noted the

present U.S. recommendations for public exposure (10 mW/cm2

) and the current U.S.S.R.

occupational guideline (0.01 mW/cm2

).

The off-center peaks in figure 13 are called

“sidelobes;” the level of intensity shown is a

consequence of the 1-km antenna aperture

(which is optimized to minimize orbital mass)

and the projected cumulative antenna errors.

The first sidelobe would have a peak intensity

of 0.08 mW/cm2

, less than one-hundredth the

current U.S. occupational exposure recommendation, about 8 km from the beam centerline; the intensity at the edge of the reference

system rectenna (5 km from the beam centerline) would be 1 mW/cm2

–one-tenth the U.S.

occupational exposure guideline.

‘w Cordon, and L M Duncan, Impacts on the Upper

Atmosphere,” Astronautics and Aeronautics, July/August 1980
70 ● Solar Power Satellites

10

5

1.0

0.01

0.005

0.001

USA standard

0 5,000 10,000 15,000 20,000

Ground radius, m

SOURCE: Department of Energy, “Satellite Power System Concept Development and Evaluation Program: Reference System Report,” DOE

report No. DOE/ER-0023, October 1978.

In addition to the relatively strong sidelobes,

the finite size of the antenna subarrays and

their projected misalinements would produce

much weaker “grating lobes, ” which for the

reference system would occur at 440-km intervals from the rectenna. The integrated intensity of these grating lobes, even for hundreds of

operational SPSs, would be well below even

the U.S.S.R. public-exposure guideline, as

shown in figure 14.

Figure 14.—Peak Power Density Levels as a

Function of Range From Rectenna

10

10

10

o 2,000 4,000 6,000 8,000

Radius from boresight (km)

I I I I I I 1 I I 1 I I o 1,000 2,000 3,000 4,000 5,000

Radius from boresight (miles)

Grating lobe spikes occur every 245 km for the 18-m subarrays used on simulations although only two grating lobes

are shown. The SPS 10-m subarrays have grating lobes

every 440 km.

SOURCE: Department of Energy, “Satellite Power System Concept Development and Evaluation Program: Reference System Report,” DOE

report No. DOE/ER-0023, October 1978.

The rectenna design is quite insensitive both

to the angular incidence of the microwave

beam (within 100, and to variations in phase or

amplitude caused by the atmosphere. Hence,

rectennas would be interchangeable; the same

satellite could power different rectennas, as

long as they were equipped with the appropriate pilot beam needed for phase control of the

transmitting antenna. The reference rectenna

would be composed of billions of dipole an-
Ch. 5—Alternative Systems for SPS Ž 71

tennas placed above a transparent wire grid.

The microwave energy received by each dipole

would pass through a rectifier circuit that

would convert it to dc power at high current

and low voltage. Several more conversions

would be necessary to condition the power for

the grid. The received power would first be

converted to ac and then transformed to highvoltage low-current 60-cycle ac power and

then either fed into ac transmission lines for

delivery to the users or reconverted to highvoltage dc for transmission, a relatively new

transmission technology.

Estimates of overall rectenna conversion efficiency run from about 80 to 92 percent, and

the extreme simplicity and repetitive-element

construction of the electrical components

would facilitate mass production at extremely

low unit cost. Reliability of the rectenna

should be extremely high, because each component would be ultrareliable and could operate redundantly. Hence replacement would be

necessary only after a large number of individual failures.

None of the substation equipment involves

technological advances beyond those that are

projected through normal development by the

electric utility industry. The major concern

that has been expressed is the large scale of

the minimum individual power unit. Current

grid control systems are quite adequate to handle near-instantaneous switching of single

power units as high as 1,300 MW. Single unit

variations of 5,000 MW could present major

control difficulties to the utilities as they currently operate10 11 (see ch. 9 for a detailed

description of utilities interface problems).

SPACE CONSTRUCTION

The mass and physical size of the space segment needed for an operational 5-GW satellite

power station are larger by several orders of

magnitude than any space system heretofore

launched and therefore require careful con-

‘“J. G. Bohn, J. W. Patmore, and H W Faininger, “Satellite

Power Systems: Utility Impact Study,” EPRI AP-1 548 TPS 79-752,

September 1980.

11 p j, Donalek, and J. L. WhYsong, “Utility Interface Requirements for a Solar Power System, ” Harza Engineering Co ,

DO E/E R-0032, September 1978

sideration of the transportation options. The

basis for all projected Earth-to-low-orbit

transportation concepts is the current U.S.

space shuttle, scheduled to become the operational mainstay of the U.S. (and much of the

world’s) space program.

Of the many possible shuttle derivatives and

other new transportation prospects, 12 NASA

selected four different types of vehicles to supply the four basic transportation functions:

●

●

●

●

The

carrying cargo between Earth and lowEarth orbit (LEO),

carrying personnel between Earth and

LEO,

transferring cargo between LEO and the

geosynchronous orbit (CEO), and

transferring personnel between LEO and

CEO.

designs of these four vehicles, called respectively, the heavy-lift launch vehicle

(HLLV), the personnel launch vehicle (PLV), the

cargo orbital transfer vehicle (COTV), and the

personnel orbital transfer vehicle (POTV), are

based on existing technology, although all

would require considerable development before reaching operational status. 13 14 15 16

Both the HLLV and the PLV would utilize

fully reusable flyback boosters similar to those

originally considered by NASA in early shuttle

designs in the late 1960’s. Both boosters would

employ methane-oxygen rocket engines for

(vertical) takeoff and airbreathing (turbofan)

engines for flyback to base for horizontal landings. The HLLV orbiter would use oxygen-

“Robert Salkeld, Donald W Patterson, and Jerry Grey (eds ),

‘Space Transportation Systems, 1980-2000, ” VOI 2, AlAA Aeroipace Assessment Series, A IAA, New York, 1978

‘‘G Woodcock, “Solar Power Satellite System Definition

Study, ” Boeing Aerospace Co., Johnson Space Center contract

No NAS9-I 5196, pt 1, report No D180-20689, June 1977; pt 11,

report No D180-22876, December 1977, pt I I 1, report No

D180-24071, March 1978

“C Hanley, “Satellite Power System (SPS) Concept Definition, ” Rockwell International Corp., Marshall Space Flight Center, contract No NAS8-32475, report No SD78-AP-0023, April

1 ’378

15 Gordon R Woodcock, “Future Space Transportation Systems Analysis Study, ” Johnson Space Center contract No.

NAS9-I 4323, Boeing Aerospace Co. report No DI 80-20242-1

(three volumes), Dec. 31,1976

“Donald P, Hearth (Study Director), “A Forecast of Space

Technology 1980-2000,” NASA SP-387, January 1976.
72 . Solar Power Satellites

hydrogen rockets essentially identical to those

of the current space shuttle, and then glide

back to base much like the shuttle does. Unlike the shuttle, it would be fully reusable; it

would have no disposable external propellant

tank.

The PLV orbiter would be very much like the

current space shuttle, but would employ a passenger-carrying module in the payload bay.

Like the shuttle, it would also use a disposable

external propellant tank, but a somewhat

smaller one. It couId carry 75 passengers, plus

the normal shuttle crew.

A fleet of COTV, all reusable, would make

the round trip from LEO to CEO, carrying the

cargo payloads up to CEO and returning

empty to LEO for reuse. They would be propelled by efficient but slow electrostatic

engines. Using low-thrust electric propulsion

would require very long trip times, of the order

of 4 to 6 months. The bases for selecting this

propulsion option were essentially minimum

cost and ready availability of the argon propellant and other materials. Such long trip

times, although suitable for cargo, are clearly

not acceptable for personnel, so a high-thrust

propulsion approach was chosen for the

POTV. The design utilizes a basic oxygenhydrogen propulsion stage now undergoing

research evaluation at NASA as part of its Advanced Space Engine program. It employs

essentially the same level of “technology as

that used in the current space shuttIe main

engine. It could carry up to 160 people from

LEO to CEO and back, or 98 tonnes (480 manmonths) of consumables from LEO to CEO.

Because it would be impractical to launch a

full-sized power satellite by single launch vehicle, a strategy for constructing the satellite in

Earth orbit would be necessary. The basic

space construction strategy selected for the

reference system is to launch all materials,

components, and people to staging areas in

LEO (fig. 15). The COTVs, because of their

large solar arrays, would be assembled in LEO

as well. The main construction base would be

located in CEO, although not necessarily at

the eventual geostationary-orbit location of

the operational SPS. Hence the LEO staging

area would serve as the transfer point for all

materials and personnel both up to CEO and

back down to Earth. Alternative strategies

have been considered, some of which will be

discussed later.

The principal factor that governs the cost

and effectiveness of in-space construction is

generally accepted to be the productivity of

the construction crew and cost, and requirements for shielding. The replacement of some

crew by automated equipment is therefore a

major consideration in alI construction strategies or scenarios, e.g., effort has already been

devoted to automatic beam-building systems. 17 The use of teleoperators and robot manipulators for assembly of large structures has

also been considered. The current growth of

technology in these areas is extremely rapid, ’8

and incorporation of such techniques would

almost certainly benefit all aspects of SPS construction. Despite the wide range of construction options, estimated personnel requirements for them are approximately the same:

750 & 200. 19

GROUND-BASED CONSTRUCTION ,

Building the rectenna, although a very large

and relatively unique structure, nevertheless

would involve far fewer uncertainties than

constructing the space segment. A detailed

analysis20 of both the basic structure and

construction aspects concluded that the primary structural material should be galvanized

or weathering steel rather than aluminum

(which is more scarce and requires a higher

energy cost to produce).

SYSTEM OPERATION

An active control system would be needed

both to keep the satellite in the proper orbit

‘Denls j Powell and Lee Brewing, “Automated Fabrication of

Large Space Structures, ” Astronautics and Aeronautics, October

1978, pp 24-29

‘

8 Antal K Bejczy, “Advanced Teleoperators,” Astronautics

and Aeronautics, May 1979, pp. 20-31

“W H Wales, “SPS Program Review Transportation Perspective, ” I n The Final Proceedings of the Solar Power Satellite Program /?ev/ew, DOE/NASA Conf-800491, July 1980

‘

O

’’ Feaslbil ity Study for Various Approaches to the Structural

Design and Arrangement of the Ground Rectenna for the Proposed Satellite, ” NASA contract No. NAS-I 5280, Bovay Engineers, In{ , May 197 7
Ch. 5—Alternative Systems for SPS ● 73

Figure 15.—SPS Space Transportation Scenario

SOURCE: W. H. Wales, “SPS Program Review Transportation Perspective,” in The Final Proceedings of the Solar Power Satellite Proqram Review, DOE/NASA

Conf-800491, July 1980. -

(stationed above the rectenna) and to maintain

the solar array’s orientation to the Sun. The

mass of the necessary control system is estimated at 200 tonnes; its average electric power

consumption would be 34 MW.

Because of its low coefficient of thermal expansion and relative stiffness, a graphite composite structural material was selected for the

reference system in preference to the aluminum alloys so widely used in aerospace structures. Although a complex engineering problem and, furthermore, one not readily subject

to testing at an adequate scale prior to deployment in space, it does not appear likely that

dynamic stability would cause any major unexpected problems in either performance or

83-316 0 - 81 - 6

costs, partly because of the predictability of

the space environment as compared, for example, with the uncertain environment in which

aircraft structures must be designed to operate, and partly because of the extensive body

of applicable design, testing, and operational

experience with high-performance aerospace

structures. However, questions of dynamic instability resulting from Iow-probability occurrences such as major meteor strikes or aggressive military action would have to be evaluated.

Orientation of the transmitting antenna relative to that of the solar array would be maintained via the large rotary joint. Physical aiming of the antenna itself would be accom-
74 ● Solar Power Satellites

plished by gyroscopes, which would feed control signals to the mechanical-joint turntable

so that it could follow the antenna pointing requirements. However, mechanical pointing of

the antenna would not have to be performed

with high accuracy, since the electronic phasing and pointing of the antenna subarrays

would be insensitive to angular deflections of

the antenna of upto100.

In addition to the equipment for satellite

station keeping and attitude control, it would

be necessary to provide routine maintenance

of both the space and ground segments. Potential maintenance problems in the space segment, in addition to the expected routine replacement of components, include the effects

of solar wind, cosmic rays, micrometeoroids,

and impacts by station-generated debris. Aside

from the solar wind and cosmic radiation effects on solar cells, which would require active

annealing of the silicon cells, none of these effects would appear to introduce significant

maintenance problems or costs, based on extensive past and current experience with operational satellites powered by photovoltaic

celIs.

Repair and replacement of the solar blankets and more than 100,000 70-kW klystrons in

the transmitting antenna are estimated to require a crew of from 5 to 20 people at the

geostationary orbit construction base,21 along

with the necessary transportation, support,

and resupply (e. g., station-keeping propellant)

services.

Maintenance requirements of the rectenna

and substation are also primarily associated

with repair and replacement of their biIIions of

components. Although a certain degree of redundancy is built into the system, a maintenance crew would still be required to replace

storm-damaged rectenna sections and routine

failures of both rectenna and substation equipment.

Technical Uncertainties of

the Reference System

Although most observers accept the basic

scientific feasibility of the SPS system con2’ DOE, op cit

cept, there are many technical uncertainties

associated with the reference system. This section identifies specific issues or problems in

the reference system that would be of importance in formulating decisions concerning the

research, evaluation, development, demonstration, and deployment of satellite power

stat ions.

●

●

●

●

Performance. A major issue in the reference

system design is the tremendous scale of the

satellite. The level of 5 GW (net output

power) is based on scaling assumptions that

could be subject to considerable change

(e.g., the transmission frequency, the antenna and rectenna power densities); multiple rectennas served by a single satellite also

constitute a potential variation.

The overall efficiency of the entire system

would be subject to considerable variation

either up or down, and would be a key factor

in all cost and technology tradeoffs. Although all system elements would involve

known technology, there is considerable uncertainty about how their efficiencies might

add up when assembled together.

Powerplant lifetime, assumed to be 30 years

for the reference system, could actually be

greater or less depending on a number of

economically interrelated factors (e. g., ease

of replacement of damaged components,

sudden technological advances in component efficiencies, etc.) This would affect all

economic projections, even allowing for

high-discount rates.

The total mass in orbit, one of the critical

parameters in assessing costs and launchrelated environmental impacts, depends on

a number of factors stilI subject to considerable variation. The power CoIlection/conversion system is an obvious factor; the reference system’s two photovoltaic options are

indicative of the significance of that tradeoff. The antenna mass is also important.

Prospects for revising the reference-system’s

100:1 ratio of rectenna-to-antenna area

could have major impact on the overall system cost and performance. The 25-percent

contingency factor is another major factor

subject to revision if R&D mature.
Ch. 5—Alternative Systems for SPS ● 75

SPS would require an extensive program of

research and testing of the numerous satellite

and terrestrial components of the system

before planning for a demonstration satellite

could be completed. In addition, substantial

improvements in components and overall technology would have to occur before the SPS

could meet the performance specifications of

the reference system. However, the current

reference system does not constitute a preferred system. It is, perhaps, technically feasible but certainly not an optimum design. It was

chosen by NASA/DOE as a model and a reference to be used in the assessment process. As

such it has the inherent I imitation that as new

information becomes available the design becomes progressively obsolete.

The following items summarize the major

technical uncertainties for the reference system and suggest possible ways to alleviate

them.

. Photovoltaic cells. The reference system

specifies a silicon solar cell efficiency of

17-percent and a mass of 2 grams per peak

watt (g/Wp). Current space-rated single

crystal silicon cells operate at 12- to 16-

percent efficiency. However, they are

about nine times as massive (18 g/Wp) as

called for in the reference system and

they cost about $70/Wp (1980). The reference system assumes a cell cost of about

$0.17/Wp. Although the issue of costs will

be addressed in more detail in a separate

section, it is clear that meeting all three

goals for the silicon cell blanket would

present manufacturers of current cell

technology with an extremely difficult

task. Normal advances in cell production

techniques would readily result in the

necessary efficiency increase. However,

the burden of achieving a nine times

reduction in weight along with a reduction in costs of a factor of 400 makes it

highly unlikely that an SPS could be built

using single crystal silicon cells.

If efficiency-mass-cost goals were met,

there would still be the problem of cell

lifetime in space and the related problem

of the feasibiIity of annealing the surface.

Silicon cells are subject to serious degradation by high energy electrons and protons in the solar wind released by solar

flares. One study” estimates that the accumulated particle damage would degrade the output from the cells by 30-

percent during the 30-year nominal life of

the satellite. The resulting damage could

be repaired periodically by annealing the

cells by either a laser or an electron beam.

The beam would sweep across the surface

of the cells and heat them briefly to several hundred degrees centigrade. Very little is known about either process in the

laboratory and nothing at ail about how

they would work in space or how much

energy they would use to anneal the surface of the photovoltaic cells. However,

experiments have shown that annealing

by electron beam is much more efficient

than laser annealing.23 Because no longterm studies have been done, the suitability of silicon cells for extended duration space applications is in question;

however, they have demonstrated excellent performance over a period of

about 10 years in operating spacecraft.

GaAs cells appear to be a more realistic

candidate for a reference-type satellite,

though they have received much less attention than the silicon cells. GaAs cells

reach higher efficiencies and can operate

at higher ambient temperatures than silicon cells. Laboratory models of GaAs

cells have reached efficiencies as high as

18 percent. 24 Because of their currently

higher unit cost, the GaAs array would

probably require refIectors to concentrate

the Sun’s rays on the cells and thereby

reduce the required cell area. Aluminized

Kapton has been suggested as a reflective

material because of its low thermal coefficient of expansion and low mass density.

2

*C R Woodcock, “SPS Silicon Reference System,” The Fina/

Proceedings of the Solar Power Sate//ite Program Review,

DOE/NASA Conf-800491, July 1980,

“B E. Anspaugh, J. A Scott-Monck, R. G. Downing, D W.

Moffett, and T. F Miyahira, “Effects of Electrons & Protons on

Ultra Thin Silicon Solar Cells, ” J PL contract No, NAS7-1OO.

“lbld
76 . Solar Power Satellites

●

●

●

Here, again, whether Kapton and GaAs

cells can maintain their integrity over the

30-year design lifetime of the satellite is

unknown. Considerably more study would

be needed to determine the feasibility of

this option.

Space charge and plasma effects. Because

of the high voltages associated with operation of the klystrons, electrical charge

buildup in the satellite components could

cause arcing and subsequent failure of

certain components.

Rotary joint/slip rings. Although the basic

technology of building a rotary joint and

an associated slip ring (for electrical continuity) is well-known, considerable uncertainty surrounds their construction and

operation on the scale of the reference

satellite in a space environment. Because

it would operate in a gravity-free environment, the design demands would be different than they are for terrestrial designs.

Klystrons. Current klystrons last about 10

years, but these are tubes especially selected for their long life characteristics

and they operate at much lower power

levels than the 70 kW required of reference system klystrons. High-power klystrons do exist, but they operate in a pulsed

mode, not continuously as the reference

system klystrons would have to. The antenna’s phased array control system

would need considerable development

and testing. Although pilot beams have

been used in other applications, and the

technology is therefore known, it is

unclear whether the power beam would

leave the ionosphere sufficiently unaffected to allow for undisturbed passage of

the pilot control beam.

Although harmonics and other noise

produced by the klystron or alternative

transmitting device would seem unlikely

to affect the natural environment adversely, they could cause radio frequency interference for communications systems (see

the discussion of ch. 8). This problem

might be severe and wouId need extensive

study, but most experiments could be carried out in ground-based testing. Alter-

●

●

natives to the klystron may provide better

noise and harmonic control (see section

on alternatives below).

Space transportation. The problems inherent in developing the capability to transport SPS components to LEO and CEO are

those of extending a mature technology,

i.e., there is sufficient understanding of

the problems to be faced that there is little doubt that the appropriate vehicle

could be developed. The most important

question is whether the necessary massive

loads could be transported for sufficiently

low costs, i.e., would reusable vehicles

prove economic? In this area, much can

be learned from experience with the shuttle

I n addition to economic concerns, there

are additional technical questions relating

to environmental effects that would require study. For instance, can the launch

vehicles fly trajectories that would keep

the effects of ionospheric contamination

to a minimum? Would it be possible to

substitute other technologies for the

argon ion engine proposed for the reference system (see ch. 8).

Construction, operations, and maintenance. There are unresolved questions

about the productivity of humans and machines in the space environment. Some

automated equipment has been built and

tested on Earth, but considerable development would be needed to choose the best

ratio between automated and human

tasks.

Alternatives to the Reference

System Subsystems

One of OTA’s goals is to explore the possible

alternatives to the reference system. Some options improve specific components of the reference system. Others would require significant redesign of the overall system. This is

because the reference system is composed of a

number of interlocking components, some of

which depend heavily on the other elements of

the system. Thus, a radical change in one component might require numerous other system
Ch. 5—Alternative Systems for SPS • 77

changes in order to create the most efficient

overall design.

A number of alternative subsystems and systems were considered in the process of electing the reference system design. Advances

have been made in some components that

were previously rejected. In addition, consideration of some of the above-mentioned technical uncertainties has engendered new designs that could alleviate these uncertainties

or resolve some of the technical problems encountered in the reference system.

The following summary lists a number of

subsystem options that could be considered as

alternatives to the reference system. A more

detailed discussion of each can be found in appendix A.

Solar thermal power conversion. Either a

Brayton- or Rankine-cycle engine offers

higher efficiency energy conversion than

photovoltaics. However, they currently

suffer from limitations on the means for

heat rejection.

Thermionic, magnetohydrodynamic

or wave energy exchanger technologies

might eventually find use in combination

with the Rankine or Brayton cycle.

Photovoltaic alternatives. Materials other

than silicon or gallium arsenide may eventually prove more viable for use in the

SPS. Currently none of the other obvious

options meet the projected standards for

efficiency, low mass, materials availability, etc., that would be needed for satellite

use. Different sorts of concentrator systems are also of interest, as is the possibility of using single cells or a combination of cells that respond to a wide portion of the solar spectrum. A possible approach would be to use a combination of

al I these variations.

Alternative microwave power converters.

Several devices other than the klystron

have been considered for converting electricity to microwaves and transmitting

them to Earth including the magnetron,

which offers the principal potential advantage of cost and low noise, and the

solid-state amplifier whose reliability

could be very high and mass low.

● Photoklystron. This device, which is stilI in

the very early stages of study, both converts the sunlight directly to microwave

power, and transmits it. If successful, it

could replace both photovoltaic cell and

amplifier.

● Offshore rectennas. For highly populated

European and U.S. coastal areas, rectennas mounted in the shallow offshore seabeds offer some advantages over long

transmission lines from suitable landbased rectennas.

THE SOLID-STATE SYSTEM

Two system approaches using solid-state

devices have been considered for the SPS. The

most direct of these simply replaces the kylstrons and slotted waveguides in the reference

system by solid-state amplifiers and dipole

antennas maintaining essentially the same

basic configuration as that of the reference

system (fig. 9); the second approach completely revises the satellite configuration by integrating the antenna and solar array in the

Earth-facing “sandwich” configuration, using a

movable Sun-facing mirror to illuminate the

solar array (fig. 16). A number of alternative

sandwich configurations have been explored

but at the moment the configuration of figure

16 seems to be the best.25

Another related subsystem option uses the

multibandgap photovoltaic cells discussed

earlier, possibly in conjunction with selective

filtering to reduce solar-cell temperatures.

When such cells are utilized in the sandwich

configuration of figure 16, they offer considerable potential mass reduction. A recent preliminary case study26 compared sandwich-type

systems such as that of figure 16 employing

single-bandgap GaAs photocelIs similar to

those of the reference system but having higher concentration ratios (CR) with optimized

multibandgap photovoitaics. Such a configuration would result in an approximate W-percent increase in power delivered per kilogram.

“G M Hanley, et al , “Satellite Power Systems (SPS) Concept

Deflnitlon Study, ” First performance Review, Rockwell international report NO SSD79-01 63, NASA MSFC contract No

NAS8- )2475, Oct 10, 1979

~bl bld
78 ● Solar Power Satellites

Figure 16.—The Solid-State Variant of the Reference System

Reflected sunlight

Detail of solar cell

blanket panel

Solid-state

amplifier

panel

Sunlight I

Microwave /

power to

Earth

/ ’

Solar array/microwave antenna

sandwich panels

SOURCE: G. M. Hanley, et al., “Satellite Power Systems (SPS) Concept Definition Study, “First Performance Review, Rockwell International report

No. SSD-79-0163, NASA MSFC contract No. NAS-8-32475, Oct. 10, 1979.

LASER TRANSMISSION

Lasers constitute an alternative to micro- ●

wave transmitters for the transmission of

power over long distance.27 They offer the fundamental advantage that at infrared wavelengths, energy can be transmitted and received by apertures over a hundred times

smaller in diameter than the microwave beam.

This obviously would reduce the size and mass

of the space transmitter and the land-area requirement of the ground receiver. But perhaps

even more important, the great reduction in

aperture area would permit consideration of

fundamentally different systems. For example:

 W H power

Satellites: The Laser Option,” Astronautics and Aeronautics,

March 1979, pp. 59,67,

The use of low Sun-synchronous rather

than high geostationary orbits for the massive space power conversion subsystem

might be possible. (A Sun-synchronous orbit is a near-polar low orbit around the

Earth that keeps the satellite in full

sunlight all the time while the Earth rotates beneath it.) In this suggested system,

the laser would beam its power up to lowmass laser mirror relays in geostationary

orbit for reflection down to the Earth

receiver, an arrangement that might considerably reduce the cost of transportation, since the bulk of the system mass is

in LEO rather than in GEO. However, system complexity would be increased due

to the need for relay satellites.
Ch. 5—Alternative Systems for SPS ● 7 9

●

●

Because the mass of the laser transmitters

would not dominate the satellite, as does

the reference-system microwave transmitter, laser satellites would not benefit nearly so much by large scale as the reference

system satellites. The resulting smaller

systems would improve the flexibility of

terrestrial power demand matching, provide high degrees of redundancy, permit a

smaller and therefore less costly system

demonstration project, and might even

preclude the need for ultimate development of an HLLV.

The small size of the receiving station

would make it possible to employ multiple locations close to the points of use,

thereby simplifying the entire ground distribution and transmission system. It

would also open up the possibility of

repowering existing powerplants, regardless of their size, simply by replacing their

steam generating units with laser-heated

boilers and/or superheaters.

The most important technical disadvantages

of laser-power transmission are the very low

efficiencies of present laser-generation and

power-conversion methods, low efficiency of

laser transmission through clouds and moisture, and the relatively undeveloped status of

laser power-system technology in general.

The laser system would consist of three

distinct elements: the laser-generation subsystem, the laser-to-electric power-conversion

subsystem, and the laser beam itself.

Laser Generators

Although the laser has become a well-known

and widely utilized device in industry, the

high-power continuous-wave (CW) laser generators needed for SPS are still in the

advanced-technology or, in many cases, the

early research phase.28 However, the technology is improving dramatically as exemplified

by the growth of laboratory-demonstrated conversion efficiencies (input power to laser

beam) from about 1 to nearly 50 percent during the past decade.

Of all the currently operating CW lasers,

only the electric discharge laser (EDL)29 seems

a feasible alternative for the SPS. The gas dynamic laser (CDL) suffers from very low efficiency if used in the closed cycles necessary

for space (i.e., the gas supply must be circulated, cooled, and reused). Chemical lasers require a continuous propellant supply that

makes them also unsuitable for long-term use

in space.

High-power density at 50-percent conversion

efficiency levels has been achieved for EDLs,

but only in the open-cycle mode for short time

periods. The closed-cycle systems needed for

SPS have yet to be tested, even in the laboratory. In theory, they should achieve high efficiencies in that mode as well, but considerable

improvement in the available technology

would be required to reach the necessary

goals.

In addition to using improved designs of currently operating lasers, several advanced concepts have been suggested. Of these, the solarpumped laser and the free electron laser (FEL)

seem most promising for the long term.

● Solar-pumped lasers. Figure 17 illustrates

the concept of a solar-pumped laser. The

energy contained in sunlight directly excites a combination of gases confined between two mirrors, which subsequently

“lase” and transmit the captured energy.

It suffers the drawback that because only

a part of the solar spectrum is useful in exciting any given Iasant gas, its conversion

efficiency is likely to be fairly low. However, elimination of the need for a separate electric power-generating system,

and the consequent reduction in mass and

complexity, could more than compensate

for this drawback. Further, in comparison

with other laser systems, the solarpumped laser’s efficiency need be only as

good as the combined power-generating

28j Frank Coney bear, “The Use of Lasers for the Transmission

of Power, ” in Progress in Astronautics, vol. 61, A IAA, N Y ,

)ui~ 1978, pp. 279-310

“G W Kelch and W. E. Young, “Closed-Cycle Gasdynamic

Laser Design Investigation, ” Pratt & Whitney Aircraft, NASA

Lewis Research Center report No CR-135530, Jan 1,1970.
80 • Solar Power Satellites

Figure 17. —Indirect Optically Pumped CO/CO2 Mixing Laser

Ps QSEP

solar n

SOURCE: R. Taussig, P. Cassady, and R. Klosterman, “Solar Driven Lasers for Power Satellite Applications,” in Firra/ Pro

ceedings of SPS Program Review, Department of Energy, p. 267

system and laser generator of other laser

systems (about 7.5-percent for a photovoltaic-powered carbon monoxide (CO)

EDL30).

Although the information exists to determine the applicabiIity of solar-pumped lasers

to SPS, adequate studies have not been done.

There is as yet little or no realistic basis for the

mass, efficiency, and cost projections proposed by several authors.31 32 33 34

‘“R. E. Beverly, “Satellite Power Systems (SPS) Laser Studies

Technical Report, Vol. 1, Laser Environmental Impact Study,”

Rockwell International SSD-80-0119-I, August 1980

“W. S. Jones, L. L. Morgan, J. B, Forsyth, and J Skratt, “Laser

Power Conversion System Analysis: Final Report, Vol. I l,” Lockheed Missiles and Space Co., report No LMSC-D673466, NASA

report No. CR-1 59523, contract No NAS3-21 137, Mar 15, 1979

32 Claud N Bain, “Potential of Laser for SPS Power Transmission, ” report No R-1 861, PRC Energy Analysls Co , DOE contract

No. EG-77-C-01-4024, September 1978

3JJohn D. G. Rather, “New Candidate Lasers for Power Beaming and Discussion of Their Appl icatlons, ” I bid,, pp. 313-332.

34 Daryl J. Monson, “Systems Efficiency and Specific Mass Estimates for Direct and Indirect Solar-Pumped Closed-Cycle HighEnergy Lasers in Space,” ref 105, pp 333-345

Free-Electron Lasers (FEL)

An FEL is powered by a beam of high-energy

electrons oscillating in a magnetic field in such

a way that they radiate in the forward direction (fig. 18). A number of pulses reinforce the

stored light between the mirrors, generating a

coherent laser beam. The high-energy density

of the relativistic electron beam is theoretically capable of producing very high-power

density lasers, and the emitted frequency is

tunable simply by changing the electron

energy.

Although efficiencies are theoretically projected to be quite high (around 50 percent for

the combined FEL and storage ring35), it is not

known whether such efficiencies could be

reached in practice. In addition, the system

mass per unit power output and the ability to

‘5John W Freeman, William B. Colson, and Sedgwick Simons,

“New Methods for the Conversion of Solar Energy to R. F. and

Laser Power, ” in Space Manufacturing ///, Jerry Grey and

Chrlstlne Krop (eds ) (New York AlAA, November 1979).
Ch. 5—Alternative Systems for SPS ● 81

Figure 18.—The CATALAC Free Electron Laser Concepts

SOURCE: R. Taussig, P. Cassady, and R. Klosterman, “Solar Driven Lasers for Power Satellite Applications,” in Final Proceedings of SPS Program Review, Department of Energy. p. 267

scale to the size and power levels of a laser

SPS are impossible to predict reliably at this

time. 36

Laser Transmission

As in the case of microwave transmission,

the fundamental parameter that governs much

of laser transmission performance is the frequency (or wavelength). At ultraviolet or visible wavelengths, absorption losses in the atmosphere are higher than for infrared wavelengths. The wavelength also affects the efficiency of the laser power absorption and conversion equipment.

At the wavelengths of CO or CO, EDLs, (5 to

10 microns), the primary mechanism of beam

attenuation is molecular absorption. Scattering by molecuIes or by aerosols in clear air is

relatively unimportant. Attenuation of the

beam by aerosols under hazy or cloudy conditions is quite significant and can completely

block the beam if the clouds are thick enough.

Although it is apparently possible to burn a

hole through thin clouds,37 the attenuation of

energy is appreciable, and because clouds are

seldom stationary, the laser would continually

encounter new water droplets to vaporize.

‘

s Beverly, op. cit.

37E. W. Walbridge, “Laser Satellite Power Systems, ” Argonne

National Laboratory report No AN L/ES-92

Transmission of the laser beam through the

atmosphere is also affected by a phenomenon

called “thermal blooming;” i.e., heating of the

atmosphere that causes it to act Iike a lens and

distort the laser beam. Scientists are currently

divided on the significance of this issue and

opinions range from assertions that it is a major factor 38 to suggestions that it could

be avoided altogether by selecting the transmitting wavelengths carefully.39 Considerable

classified research is now being carried out on

this effect in connection with laser-weapons

research. Some of this work might be applicable to SPS use, though in general the military

lasers are pulsed, not CW systems. The difference could be critical and should be studied

carefulIy.

With regard to laser optics, it is important to

develop components capable of low-loss, highpower-density transmission and reflection of

laser light.40 It appears that adequate technology for SPS systems has a high probability

of being available within the next 20 to 30

years, due primarily to advances being made in

current military laser research and technology

programs.

“Jones, et al , op cit

“Beverly, op. cit

40 Baln, op cit
82 Ž Solar Power Satellites

Transmission options for SPS lasers are

essentially of two types: a narrow, highly concentrated beam or a wide, dispersed beam (fig.

19). Advantages of the narrow beam are the

reduced land area needed and the smalI size of

the ground power-conversion system; problems include potential environmental and

safety impacts of the high-intensity beam, concerns over military uses, and the need for sophisticated high-temperature receivers and

power-conversion equipment. Advantages of

the dispersed beam are its less severe environmental impact, the possible use of low-performance optics, and simplicity of low-powerdensity receiving systems. Disadvantages include relatively high atmospheric dissipation,

larger land area required and the large mass of

Earth receptors. It is probably too early to

make an informed selection between the two

options, but the narrow-beam approach appears to offer the principal benefit compared

to reference-system microwave transmission.

A final concern is the ability to point and

control the beam to make sure it would always

remain within the designated receiver area and

to shut it off instantly should it stray. The

adaptive-optics approach to beam control

(e.g., phased-array) such as would be used for

the microwave beam, appears adequate to

provide the necessary pointing accuracy and

to ensure safety, since any loss of phasing control would cause loss in coherence of the several lasers making up the beam, and each

beam by itself would transmit far too little

power to cause any problems. Adaptive optics

systems are being studied for use in military

directed energy weapons and look promising.”

It should be emphasized that the overall system constraints might be quite different for

the large CW lasers needed for SPS than for

pulsed military examples.

Laser-Power Conversion at Earth

Several approaches are possible for converting high-energy-density laser radiation to useful electric power. The technology of laser

energy converters is relatively new, but progress has been rapid. Laboratory models have

achieved conversion efficiencies of 30 to- 40

percent and designers project eventual efficiencies of 75 percent for some versions. Table

6 summarizes the available technology and

projects future potential efficiencies. 42

The Laser-Based System

Lockheed43 has generated one possible laser

system (fig. 20) that utilizes power satellites in

4’Claud N Bain, “Power From Space by Laser,” in “High-Powered Lasers In Space, ” Astronautics and Aeronautics, vol. 17,

March 1979, pp 28-40

“(;eorge Lee, “Status and Summary of Laser Energy Conversion, ‘ In Progress in Astronautics, VOI 61 Al AA, N Y , July

1978 pp 549-565

4’Jones, et al , op clt

Figure 19.—Optics and Beam Characteristics of Two Types of

Laser Power Transmission System (LPTS) Concepts

Optics Optics

m

SOURCE: Claud N. Bain, “Potential of Laser for SPS Power Transmission,” report No. R-l WI,

PRC Energy Analysis Co., DOE contract No. EG-77-C-01-4042, September 1978.
Ch. 5—Alternative Systems for SPS ● 8 3

Table 6.—Projections for Laser Energy Converters in 1981-90

Current 1981-90

Photovoltaics. . . . . . . . . . . .

Heat engines . . . . . . . . . . . .

Thermionics . . . . . . . . . . . . .

Photochemical cells . . . . . .

Optical diodes . . . . . . . . . . .

—30% efficiency

—megawatt power levels

—wavelengths below 1 micron

—Piston engine: Otto or diesel cycles

—50% efficiency

—1-10 k W

—wavelengths near 10.6 microns

—40% efficiency

—1-10 kW

—wavelengths near 10.6 microns

—Photoassisted dissociation of water

—15Y0 efficiency

—wavelengths near 0.4 microns

—Evaporated junction arrays

—not ready to convert power

—45% efficiency

—megawatt power levels

—wavelengths below 1 micron

—Turbine

—75% efficiency

—megawatt power levels

—wavelengths near 5 microns

—50% efficiency

—megawatt power levels

—wavelengths near 5 or 10 microns

—Photoassisted dissociation of water

—30% efficiency

—wavelengths near 0.6 microns

— Evaporated junction arrays

—50% efficiency

—megawatt power levels

—respond to wavelengths from UV to

over 10 microns

SOURCE: George Lee, “Status and Summary of Laser Energy Conversion,“ in Progress in Astronautics, vol. 61, AlAA, N. Y., July 1978, pp. 549-565.

low Sun-synchronous orbit and relay satellites

(laser mirrors) both in LEO and CEO. One geostationary relay serves each power satellite.

Based on an analysis of five candidate systems

in three power ranges, Lockheed selected a

CO, EDL powered by a wave energy exchanger

(EE) binary cycle and a similar binary cycle for

ground power conversion.

The specific 500 MW system selected is diagramed in figure 21; hardware details of the

power satellite appear in table 7, and the Over- .

all system characteristics are summarized in

table 8.

A major potential advantage of the laser

system is that it could be demonstrated via a

subscale 500-kW pilot program using the space

shuttle to deliver the power and relay satellites

into LEO orbits.

Other laser systems are possible. For example, Rockwell44 has investigated a geosynchronous laser SPS powered by photovoltaic

ceils and using 20 to 24 100-MW CO EDL

lasers. The CO laser was chosen because it has

greater overall efficiency and is lighter than a

C 02 laser.

This study will use the LEO-based C02 laser

system in its subsequent analysis because of

‘*Beverly, op. cit.

the significant difference in space basing (i. e.,

LEO rather than CEO) which it presents compared to the reference system. Because of the

significant uncertainties present in the laser

systems concepts and the relative lack of technology base for laser devices, the optimum

laser system would undoubtedly look rather

different from any system so far devised.

A laser system that used photovoltaic arrays

to collect and convert the Sun’s energy would

suffer from the fundamental difficulty that the

overalI efficiency of the system wouId be quite

low compared to projected reference system

efficiency .45 The major limiting factors are the

projected efficiencies of the laser itself (50 percent for an EDL), the atmospheric transmission (84 to 97 percent), and the conversion efficiency of the terrestrial receptor (40 to 75 percent). When multiplied together with the

higher efficiency of other system components,

they result in an overall efficiency of 17 to 36

percent after photovoltaic conversion of sunlight to electricity to power the laser. When the

efficiency of the solar cells (17 percent) is

taken into account, the overalI system efficiency falls to only 2.8 to 6 percent compared to

the projected reference system efficiency of 7

percent. Although this decrease would con45D0E, op. cit.
Ground site

SOURCE: W. S. Jones, L. L. Morgan, J. B. and J. “Laser Power Conversion Analysis: Final Report, Vol. Lockheed Missiles and Space

Co., report No. NASA report No. CR-159523, contract No. 137, Mar. 15, 1979.

Figure 21 .—Components of the Laser Concept

Synchronous relays

Occulted ,

Power

SOURCE: W. S. Jones, L. L. Morgan, J. B. and J. “Laser Power Conversion System Analysis: Final Report, Vol. 11,” Lockheed Missiles and Space Co.,

report No. NASA report No. CR-159523, contract No. 137, Mar. 15, 1979
Ch. 5—Alternative Systems for SPS • 85

Table 7.—500 MWe Space Laser Power System

Power

generation Spacecraft,

EE/binary and structure, Transmitter aperture

Collector Solar cavity cycle conditioning Laser radiators, etc. and optical train

Unit efficiency (%) . . . . . 85 86 73.5 93.1 23 98.7

System efficiency (%) . .

—

85 73.1 53.7 50.0 11.5 — 11.4

Power in (MW). . . . . . . . . 7,913 6,726 5,784 4,251 3,958 910

Power out (MW). . . . . . . .

—

6,726 5,784 4,251 3,958 910 899

Orbital weight (kg) . . . . . 242,850

—

517,750 1,326,330 717,660 1,809,000 128,653 97,811

Spacecraft 4,108 Telescope (2)

89,812

Structure 94,433 Beam reduction

5,379

Radiators 6,032 Phasing array

1,539

Stabilization Optical train 1,181

24,080

Space Atmospheric Ground Thermal Binary Electrical

transmission Space relay transmission receiver cavity cycle generation

Unit efficiency (%) . . . . . 95 99 85 96 98 75.5 98

System efficiency (%) . . 10.8 10.7 9.1 8.7 8.5 6.5 6.3

Power in (MW). , . . . . . . . 899 854 845 718 690 676 510

Power out (MW). . . . . . . . 854 845 718 690 676 510 500

Orbital weight (kg) . . . . . – 105,438 — — — — —

Transmitter 44,703

Receiver 46,729

Optical train 945

Spacecraft 5,900

Radiators 5,762

Structure 1,023

Miscellaneous 376

SOURCE: W. S. Jones, L. L., Morgan, J.B. Forsyth, and J. Skratt, “Laser Power Conversion System Analysis: Final Report, Vol. 11,” Lockheed Missiles and Space Co.,

report No. LMSC-D673466, NASA report No CR-159523, contract No. NAS3-21 137, Mar 15, 1979.

Table 8.—Laser Power Station Specification

Solar power collected (MW). . . . . . . . . . . . . . . . . 7,913.0

Collector diameter(m). . . . . . . . . . . . . . . . . . . . . 2,710.0

Electrical power to laser(MW) . . . . . . . . . . . . . . 3,958.0

Laser power output (MW) (20 lasers

at 45.5 MW each). . . . . . . . . . . . . . . . . . . . . . . . . 910.0

Transmitter, aperture diameter (m). . . . . . . . . . . 31.5

Secondary mirror diameter (o). . . . . . . . . . . . . . . 3.0

Transfer mirror size (m) . . . . . . . . . . . . . . . . . . . . 3.0 x 4.2

Mirror reflectivity (%). . . . . . . . . . . . . . . . . . . . . . 99.85

Optics heat rejection (MW) . . . . . . . . . . . . . . . . . 11.8

Radiator area (m2). . . . . . . . . . . . . . . . . . . . . . . . . 2,656.7

Mirror operating temperature (“C) . . . . . . . . . . . 200.0

stitute a potential problem for the laser

system, it must be emphasized that many other

complex factors (e. g., the smaller terrestrial

receivers, or lower mass in GEO), might compensate in complex ways for lower efficiency.

When added up, the combination might make

the laser system more acceptable overall than

the microwave systems. ’b

“Abraham Hertzberg and Chan-Veng Lau, “A High-TemperaSOURCE: W. S. Jones, L. L., Morgan, J. B. Forsyth, and J. Skratt, “Laser Power

ture Ranklne Binary Cycle for Ground and Space Solar AppIicaConversion System Analysis: Final Report, Vol. 11,” Lockheed tions, ” m “Radiation Energy Conversion in Space, ” K W,

Missiles and Space Co., report No. LMSC-D673466, NASA report No. Billman (cd,), Progress in Astronautics and Aeronautics, vol. 61

CR-159523, contract No. NAS3-21137, Mar 15, 1979. (New York, AlAA, July 1978), pp 172-185.
86 . Solar Power Satellites

MIRROR REFLECTION

Instead of placing the solar energy conversion system in orbit as in the reference SPS,

several authors have suggested using large orbiting mirrors to reflect sunlight on a 24-hour

basis to ground-based solar-conversion systems. 47 48 49 50

Typically, this option would use plane mirrors (fig. 22) in various nonintersecting lowaltitude Earth orbits, each of which directs

sunlight to the collectors of several groundbased solar-electric powerplants as it passes

over them (the so-called “SOL ARE S“ concept).

Each mirror would be composed of a thin

film reflecting material stretched across a supporting structure made up of graphite-reinforced thermoplastic. As they pass within

range of the terrestrial receiving station, the

mirrors would acquire the Sun and the ground

station nearly simultaneously. They would

maintain pointing accuracy by means of builtin reaction wheels.

Two typical “limiting cases” have been identified from among several alternatives.51 one

wouId use a 1,196-km circular equatorial orbit

(O 0 latitude) serving 16 equatorial ground stations each generating about 13 CW (baseload,

with minimum storage) and another 6,384-km

40 ‘-inclination circular orbit serving four 375

GW ground stations at 300 latitude. Additional

ground stations in each case (to accommodate

demand growth) could be achieved simply by

47 Hermann Oberth, “Wege zur Raumschiffahrt, ” OldenburgVerlag, Berlin, 1929; also see “Ways to Spaceflight, ” NASA technical translation TT F-662

48 Krafft A Ehricke (for example), “Cost Reductions in Energy

Supply Through Space Operations, ” paper IAF-A76-24, 27th lrrternationa/Astrorraut;ca/ Congress, Anaheim, Calif , Oct. 10-16,

1976.

“K, W. Billman, W, P Gilbreath, and S W Bowen, “introductory Assessment of Orbiting Reflectors for Terrestrial Power Generation,” NASA TMX-73,230, April 1977

‘“K, W. Billman, W. P. Cilbreath, and S W Bowen, “Orbiting

Mirrors for Terrestrial Energy Supply, ” in “Radiation Energy Conversion in Space,” K, W, Billman (ed ), Progress in Astronautics

and Aeronautics Series, VOI 61 (New York Al AA, July 1978), pp

61-80

“K. W. Billman, W. P. Gil breath, and S W. Bowen, “Solar

Energy Economics Revisited: The Promise and Challenge of Orbiting Reflector for World Energy Supply,” DOE SPS Program

Review, June 8,1979.

increasing the orbit altitude and mirror size,

which increases the size of the illuminated

ground circle and thereby permits the use of

larger ground stations.52 The orbiting mirrors

themselves could probably be quite large (up

to 50 km’ each) with very low mass density53

and still maintain their required optical surface flatness in the presence of disturbing

forces.

A mirror system would offer the following

potential advantages:

●

●

●

●

●

●

●

●

The space segment would be simple and

of low mass. It would consist only of

planar reflective thin-film mirrors.

It would minimize the need for large-scale

space operations, since recent designs

allow terrestrial fabrication and packaging with automatic deployment i n space.

The system would be modular and highly

redundant, i.e., there would be many identical mirrors capable of mass production.

The mirrors would operate at low-orbit altitudes, thus not requiring the CEO transportation system of some other alternatives.

It would eliminate the need for developing microwave- or laser-transmitting technology.

The mirrors would reflect ordinary sunlight, thus eliminating many of the potential damaging environmental effects due

to laser or microwave transmission.

It could be used for a variety of terrestrial

uses where enhanced 24-hour sunlight

wouId be useful. SOLARES couId increase

the solar product fivefold over the same

system operating on ambient sunlight.

Demonstration would be very inexpensive

compared to laser or microwave options.

‘2K W Billman, “Space Orbiting Light Augmentation Reflector Energy System: A Look at Alternative Systems,” SPS Program

Review, June 1979.

“John M Hedgepeth, “Ult[ ghtweight Structures for Space

Power, ” in “Radiation Energy Conversion in SpaceJ” K W, Billman (ed ), Progress in Astronautics and Aeronautics, vol. 61 (New

York Al AA, j uly 1978), pp. 126-135.
Ch. S—Alternative Systems for SPS ● 87

Figure 22.–The Mirror Concept (SOLARES)

Photo credit: National Aeronautics and Space Administration

SOURCE: W. Bill man, “Space Orbiting Light Augmentation Reflector System: A Look at Alternative Systems,” 

Review, June 1979. -.

On the other hand, mirror systems would ●

possess the following potential disadvantages:

● They would require a large number of satellites each with individual attitude con- ●

trol. Maintenance might be expensive and

difficult to accomplish.

The mechanisms needed to keep

rors pointed accurately might be

cated.

the mircompliThe mirrors might cause unwanted weather modifications around the ground stations (see below and ch. 8).
88 ● Solar Power Satellites

●

●

●

Scattered light from the mirrors and the

light beams in the atmosphere would interfere with astronomical research (see

ch. 8).

The large power production per site (10 to

135 GW) and necessary centralization of

the electrical supply from them would not

be attractive to the utilities (see ch. 9).

The large area of the receiving sites (100

to 1,000 km2

) would be likely to make

land-based siting extremely difficult if not

impossible from a sociopolitical standpoint (see ch. 9).

The Mirror System

The “baseline” Mark 1 SOLARES54 design

(table 9) would require a total mirror area of

nearly 46,000 km2

. If each mirror were 50 km2,

about 916 of them would be necessary for a

global power system that would produce a

total of 810 GW from six individual sites, or

about twice 1980 U.S. electric generation. It

was chosen for comparative purposes because

it demonstrates the potential for large scale

energy output that might be achieved with mirrors. It is by no means the optimum SOLARES

system. A low-orbit version (altitude 2,000 km)

with 15 smaller ground stations (10,000 to

13,000 MW output) might be more feasible or

desirable. One of the principal features of the

SOLARES concept is that it could be used for

any energy use where enhanced sunlight would

be used to advantage. By using many more

smaller mirrors, the mass per unit area could

be minimized, and the total mass in orbit for

the entire baseline system then becomes about

4X105 tonnes. Thus, the entire SOLARES

baseline system would require only the same

mass in space as eight 5,000 MW reference system satellites.

Several Earth-based energy production

methods currently under development might

be used in conjunction with orbital reflector

systems: 1 ) photovoltaic arrays of varying sizes

are projected for commercial deployment in

the late 1980’s, and 2) solar-thermal electric

54 Billman, et al., “Solar Energy Economics Revisited. The

Promise and Challenge of Orbiting Reflector for World Energy

Supply, ” op. cit

Table 9.—SOLARES Baseline System

configuration:

Space system

4,146km inclined orbit, 45,800km2 total mirror area

Ground system

6 sites with DOE 1986 goal solar cells @ 15% efficiency

11 0/0 overall system conversion efficiency, ~~-circle

area = 1.168km2 each, 135 GWe each

Impact:

Total system would produce 3.24 times current U.S. consumption, total area = 84 x 84km2 (52 x 52 mi2

)

Baselined costs (in 1977 dollars)

Implementation schedule

5-year development, design, test, and evaluation (DDTE)

2-year manufacturing and transport fleet facilities

preparation

6-year space and ground hardware construction

System complete about 1995

Direct costs estimate (billions of dollars)

Facilities . . . . . . . . . . . . . . . . . . . . ... ... ... ... ..$ 47.30

Hardware. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 885.65

Total direct . . . . . . . . . . . . . . . . . . . . ... ... ... .$932.95

Indirect costs estimate (billions of dollars)

15% contingency on direct costs ... ... ... ... .. $139.94

Design, development, test, and evaluation . . . . . . 43.80

Interest a

:

Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.58

Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101.26

DDTE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.01

Total indirect. . . . . . . . . . . . . . . . . . . . . ... .. .$349.59

Total cost . . . . . . . . . . . . . . . . . . . . ... .. . $1,282.54

Indirect cost factor. . . . . . . . . . . . . . . . . . . . . . . . . . .....1.38

Installed cost per rated output ($/kWe)b

. . ...........1,508

Capacity factor(%) . . . . . . . . . . . . . . . . . . . . . . . . . .......95

1995 O&M costs:

Fixed ($/kW-y). . . . . . . . . . . . . . . . . . . . . . . . . . . . ........3

Variable (mills/kWh). . . . . . . . . . . . . . . . . . . . . . . ........2

Levelized capital cost (mills/kWh) C . .................27.2

Levelized O&M cost (mills/kWh)d . . . . . . . . . . . . . . . . . . . . 4.5

Levelized busbar energy cost (mills/kWh)e

. . ..........31.6

Comparison baseload power systems (CIRCA 1995):

Conventional coal/nuclear mixf

Levelized busbar energy cost (mills/kWh)e . . .......45

Ambient sunlight photovoltaicf g

Levelized busbar energy cost (mills/kWh). . .......115

a4Y@ first year, 8% per annum until positive cash flow after Year 11.

blncludes all direct costs, 157” contingency, interest during implementation at

8% per annum.

c15% fixed charge rate 30 years at 60/0 annual inflatiOn.

d30 years at 6% annual’ inflation,

e15y& fixed charge rate.

fsee text; these d. not include their historically eXtenSive R&D costs that are

Included, in SOLARES costing.

91Jses same terrestrial costing algorithm as SOLARES that results in indirect

cost factor of 1.37.

SOURCE: K. W. Billman, W. P. Gilbreath, and S. W. Bowen, “Solar Energy -

Economics Revisited: The Promise and Challenge of Orbiting

Reflector for World Energy Supply,” DOE SPS Program Review,

June 8, 1979.

plants should become commercially feasible

in selected locations about the same time, possibly also for “repowering” of existing coal- or

oil-fired fossil-fuel plants with solar boilers.

Much of the economic disadvantage of both

types of solar-electric powerplants is associ-
Ch. 5—Alternative Systems for SPS Ž 89

ated with the energy storage needed to allow

them to serve as intermediate or baseload

plants. Should these plants prove to be even

marginally successful, relieving their storage

needs by keeping them I it for 24 hours a day by

sunlight from orbiting reflectors would enhance the attractiveness of these terrestrial options.

The various benefits of a mirror system must

be weighed against the percentage of time the

ground-based energy production facilities

would be obscured by clouds, smog, fog, and

other atmospheric obstruct ions. However,

there is some evidence” that the concentrated

sunlight provided by the orbiting mirrors

would tend to disperse water-based obscurations such as clouds and fog, as a consequence

“Ibid

of the accelerated evaporation produced by

the high-intensity solar radiation.

If the orbiting mirrors can disperse clouds of

moisture around the SOLARES ground station,

what effects may they have on the climate

nearby? Large orbiting mirrors have been suggested for use in climate modification,56 but

their possible detrimental side effects have not

been studied (see ch. 8). However, even if

reflected sunlight could be shown to have a

salutary effect on certain regions of the Earth,

there is no reason to believe, without further

study, that regions whose weather patterns

could benefit from enhanced sunlight would

necesssariIy coincide with the SOLARES

ground stations.

—

*’I Bekey and J E Nagle, “Just Over the Horizon in Space,”

Astronaut/es and Aeronautics, May 1980.

SPACE TRANSPORTATION AND CONSTRUCTION ALTERNATIVES

Space transportation and construction (with

the possible exception of SOLARES) are common to all the options. NASA contractors who

developed the transportation, construction,

and assembly plan for the reference system

devoted considerable effort to the process

of winnowing out a host of alternative approaches. Nevertheless, several other construction/assembly schemes have been proposed for

various phases of SPS program development.

If feasible, they would mostly serve the purpose of reducing costs by using technology

developed for other programs or by reconfiguring the reference system scenario. Because

transportation costs are a significant percentage of any systems cost (see section on costs

below), it would be important to explore these

alternatives fulIy.

Transportation

Transportation strategy in the early development phase and engineering verification is to

use the shuttle or an upgraded shuttIe to their

maximum capacities. In these, as well as later

demonstration and production phases, using

shuttle size vehicles at high launch rates could

be cheaper than developing and using larger

launch vehicles (see section on costs). Perhaps

the most obvious approach is to upgrade the

shuttle-based space transportation system to

perhaps five times the capability (i.e., total

mass to space in a given time as represented by

payload size, launch rate, and turn-around) of

the present shuttle.57

The need to conduct relatively sizable experiments, and possibly prototype or demonstration projects in geostationary orbits rather

than in low-Earth orbits, would pose a serious

transportation problem. Current space-shuttle

upper stages, or “orbital transfer vehicles, ” are

not capable of carrying large payloads to geostationary orbit and are not able to support

any servicing operations there, since these

units are not reusable.

Several innovative approaches have been

suggested that circumvent the need for developing new vehicles. One such approach employ; an in-orbit propel

‘

7 Salkeld, et al,, op. cit.

ant processing facility

83-316 0 - 81 - 7
90 ● Solar Power Satellites

built into one of the shuttle’s big “throwaway”

propellant tanks to convert water into hydrogen and oxygen –the best propellants for highperformance rocket engines. The water required as the feedstock for this process would

be carried into LEO as an “offload” on every

space shuttle flight whose payload is less than

the maximum shuttle capability. The hydrogen

and oxygen, after being liquefied and stored in

the propellant processing facility’s tank, are

then used as the propellants for a reusable lowthrust “space tug” whose principal component

is also a leftover shuttle propellant tank. The

tug, which replaces the cargo orbital transfer

vehicle of the reference system, would carry

SPS prototype or demonstration hardware up

to CEO. Although such a system is rather completely defined,58 considerable technology advancement and development would be required, e.g., for the in-orbit electrolysis and

liquefaction plants, the space-tug-development, and the system logistics and integration.

Cost estimates have not yet been released.

Nevertheless, this concept represents an interesting suggestion for eliminating the development of a major new (or upgraded)

launch vehicle just for an SPS demonstration,

thereby reducing the “up-front” costs of any

sizable SPS prototype or demonstration project.

Another scheme would use an electromagnetic propulsion device59 called a “mass

driver” to provide orbital transfer thrust instead of the chemical-rocket-powered space

tug. The mass driver is simply a solar-powered

linear electric motor, which derives its thrust

by accelerating chunks of waste mass (e.g.,

chopped-up or powdered shuttle propellant

tanks) into space at high exhaust velocities. 60 61

Since it uses electricity, its energy could come

directly from the Sun via photoelectric conver58 Central Dynamics Corp (Convair Dlvlslon), “Utilization of

Shuttle External Tank in Space, ” unpublished presentation, j une

1978.

5~F, Chiiton, B, H ibbs, H. Kolm, G K O’Neill, and J. phil lips,

“Electromagnetic Mass Drivers,” in “Space-Based Manufacturing From Nonterrestrial Material s,” G K C)’Neil I (cd.), Progress in

Astronautics and Aeronautics, vol. 57 (New York AlAA, August

1977), pp. 37-61.

bochllton, et a]., “Mass-Driver Application s,” ibid , PP. 63-94.

“Gerard K O’Neill, “The Low (Profile) Road to Space Manufacturing,” Astronautics & Aeronautics, March 1978, pp. 24-32.

sion. This concept is far more ambitious than

the in-space propellant processing scheme; furthermore, it depends on a device that, although tested extensively on Earth in experimental high-speed trains and in the laboratory,

has yet to be demonstrated at the scale and acceleration levels required by the orbital transfer application. A modest research effort on

this concept is currently being supported by

NASA’s Office of Aeronautics and Space Technology.

The production phase of the SPS program

would present a number of opportunities for

transportation alternatives that could not only

reduce production costs, but could also mitigate environmental and other impacts. Because of the high proportion of total space segment construction costs (both nonrecurring

and recurring) taken up by transportation,

many of the proposed innovations center on

alternatives to the family of four transportation vehicles selected for the reference system.

The most direct approach to transportation

cost reduction would be to improve the HLLV,

since it absorbs the bulk of transportation

development and operations costs. The most

likely technological alternative appears to be

the use of fully reusable single-stage-to-orbit

(SSTO) vehicles. 62 Very advanced winged

SSTO vehicles that could reduce LEO payload

delivery costs to the order of $1 5/km are projected as becoming practical in the last decade

of this century, provided sufficient demand

exists. 63

For orbital transfer the personnel and cargo

orbital transfer vehicles selected for the

reference system probably represent the best

available technology in the two principal options: chemical and electric propulsion.

Alternatives for routine high-mass payload

hauling might include solar sails, laser propulsion, and various forms of electric propulsion

other than the ion (electrostatic) rocket described for the reference system, e.g., elec62 Beverly Z. Henry and Charles H Eldred, “Advanced Technology and Future Earth-Orbit Transportation System s,” in Space

Manu(actur;ng Facilities //, jerry Grey (ed ) (New York: Al AA,

Sept 1, 1977), pp 43-51

“lbld
Ch. 5—Alternative Systems for SPS ● 91

tromagnetic (plasma) thrusters or the mass

driver discussed above. None of these options

has been studied in enough detail to make

choices about them at the present time.

Space Construction

As currently designed, the space component

of the reference system would be constructed

in CEO. However, it may be more cost effective to build the necessary facilities and

satellites in LEO and transport them to CEO

fully constructed. Such a scenario would reduce the number of personnel needed in CEO

as well as lower the total mass that must be

transported there.

Introducing one of the LEO scenarios (i. e.,

laser or mirrors) would open up significant

changes in the construction and transportation

option for the SPS. Even a change in one major

component of the reference system satellite

could alter the ways in which the transportation and construction components are configured. For example, if the photovoltaic cells

were to be replaced by solar thermal conversion systems, it would be attractive to construct satellites in LEO and transport them to

CEO on their own power because they would

suffer less from passage through the Van Allen

radiation belts.

Of all the alternative options for SPS construction in the production phase, the prospective use of nonterrestrial materials is perhaps

the most innovative and, ultimately, capable

of the maximum potential return on investment.

The basic premise of the nonterrestrial materials option is that the cost, energy and materials requirements, and environmental impact

of lifting the enormous cumulative masses

needed to establish and operate a system of

many satellite power stations off the Earth can

be markedly reduced by utilizing first lunar

materials, and eventually materials obtained

from asteroids. The fundamental physical principle that supports this premise is that it takes

over 20 times as much energy to launch an object to geostationary orbit from the Earth as it

does from the Moon, and the situation for asteroidal materials could be even more favorable. The primary drawback is the high “upfront” cost of establishing the necessary mining base on the Moon and the space-based facility needed to construct and assemble the

SPS. Hence, it is not likely that nonterrestrial

materials would be used in the prototype,

demonstration, or even the early phases of SPS

production. However, if a commitment is

made to produce a large-scale SPS system in

CEO, the lunar materials supply option could

well be less expensive than the Earth-launched

option (including payback of the initial investmerit). 64 It has been argued that by “bootstrapping” the operation (i. e., using nonterrestrial

material right from the beginning, not only to

build the SPS but to build all the necessary

facilities as well), there is no need for any new

launch-vehicle development (a major element

in the “up-front” investment); i.e., the present

space shuttle can provide all the Earth-launch

space transportation needed to implement an

operational multi-SPS network. 65

Decisions on the nonterrestrial materials option clearly hinge on the results of current and

projected SPS technology studies and experiments. Sufficient research on the two technological factors unique to nonterrestrial materials development—the mass driver (both for

lunar materials transfer and for in-space propulsion) and lunar materials mining and processing capability —should be done so that a

decision to proceed with either the Earth or

nonterrestrial materials options could be properly made. Other study and research requirements for the nonterrestrial materials option

include system analyses (including design of

an SPS that maximizes the use of lunar materials), more intensive searches for appropriate

Earth-approaching asteroids, and establishing

capabilities for the host of space operational

functions needed for other space programs.

As is clear from the preceding discussion, it

is difficult to establish a priori alternatives to

construction, assembly, and transportation,

“Davld L Akin, “Optimization of Space Manufacturing Systerns, ” in Space Manufacturing ///, Jerry Grey and Christine Krop

(eds ) (New York. AlAA, November 1979)

b50’Nelll, op cit
92 . Solar Power Satellites

since each of the SPS alternative options

would call for a different approach. General

guidelines can be identified, minimizing

transportation and construction costs during

the evaluation, development, prototype, and

demonstration phases by: 1) utilizing a phased,

step-by-step approach (e. g., ground-based experiments, only then followed by dedicated

space experiments); 2) maximizing use of the

essentially developed space shuttle; 3) maximizing the common utilization of technology

and development efforts by other programs

having related requirements (e.g., large communications antennas and other large space

structures, spacecraft power generation, control and transmission, etc.); and 4) developing

new transportation vehicles and construction

hardware only when economically necessary.

SPS COSTS

Although knowledge of the overall costs of

an SPS program will be essential to making a

decision about developing the SPS, current

cost estimates are inadequate. Today’s projections are based on extrapolations from current

technology and in most cases assume major

advances. Thus, the technical uncertainties of

the concept are too great to provide a firm

basis for economic analyses. Here, as in most

other areas, it is only possible to develop the

foundation for future analysis that would seek

to reduce the current uncertainties.

Reference System Costs

The most detailed cost estimates have been

made by NASA66 for the reference system (fig.

23). According to these estimates, which are

based on detailed hardware specifications and

associated transportation and industrial inf restructure, achieving the first complete

reference system satellite will require an investment of $102.4 billion over a 20-year

period. Figure 24 illustrates one estimate67 of

how the costs could be allocated over time.

Each additional copy of the satellite and associated terrestrial facilities would cost $11.3

billion. Expenses are divided into the following

phases:

● Research — $370 million. This phase of SPS

development (table 10) is by far the smallest, constituting less than 0.4 percent of

the total SPS program. About half of these

bbPiland, op. cit.

“Woodcock, “Solar Power Satellite System Definition Study,”

op. cit.

Figure 23.—Reference System Costs

(dollars in billions)a

aNASA estimates—1977 dollars.

SOURCE: National Aeronautics and Space Administration
Ch. 5—Alternative Systems for SPS ● 93

Figure 24.— How Cost Could Be Allocated

o

Years

SOURCE: National Aeronautics and Space Administration.

Table 10.—Research—$37O Million

Millions Percent

of dollars of total

Power generation . . . . . . . . . . . . . . $ 79 21

Power transmission . . . . . . . . . . . . 40 11

Structures and control. . . . . . . . . . 22 6

Space construction . . . . . . . . . . . . 25 7

Space transportation . . . . . . . . . . . 20 5

System studies. . . . . . . . . . . . . . . . 19 5

Research flight test . . . . . . . . . . . . 165 45

$370

SOURCE: National Aeronautics and Space Administration.

●

●

costs are chargeable to the development

of the transportation system.

Engineering–$8 billion. This part of the

program (table 11) contributes the complex engineering knowledge necessary for

creating a useful space structure. The

work includes developing an engineering

test article in LEO, capable of generating

1 MW of power. It is the direct precursor

to the demonstrator and provides the testing ground for constructing and using collector and transmitting subarrays, a rotary

joint and satellite attitude control.

Demonstration –$23 billion. This phase of

the reference program (table 12) culminates in a 300-MW satellite and the assoTable 11.—Engineering—$8 Billion

—

Millions Percent

of dollars of total

SPS. . . . . . . . . . . . . . . . . . . . . . . . . .

Test article hardware . . . . . . . . . . .

LEO base (8 man) . . . . . . . . . . . . . .

Manned orbital transfer vehicle. . .

Shuttle flights. . . . . . . . . . . . . . . . .

Shuttle booster. . . . . . . . . . . . . . . .

Management and integration . . . .

Total. . . . . . . . . . . . . . . . . . . . . . .

$ 370 5

210 3

2,400 30

1,200 15

870 11

2,900 36

61 1

$8,000

NOTE: Percentages do not total 100% due to rounding errors.

SOURCE: National Aeronautics and Space Administration.

Table 12.—Demonstration—$23 Billion

Millions Percent

of dollars of total

Demonstrator:

DDT&E . . . . . . . . . . . . . . . . . . . . . $2,700

Hardware. . . . . . . . . . . . . . . . . . . 2,500

Pilot production facilities . . . . . . . 400

Shuttle DDT&E and fleet . . . . . . . . 3,000

Construction:

DDT&E . . . . . . . . . . . . . . . . . . . . . 3,100

Hardware. . . . . . . . . . . . . . . . . . . 3,000

Space operations (4 years

operations, construct bases,

and demonstrations) . . . . . . . . . 2,800

Personnel orbital transfer vehicle

(DDT&E and hardware). . . . . . . . 1,700

Electric orbital transfer vehicle

(DDT&E) . . . . . . . . . . . . . . . . . . . . 1,800

Demonstration rectenna . . . . . . . . 1,800

Management and integration . . . . 200

12

11

2

13

13

13

12

7

8

8

1

Total. . . . . . . . . . . . . . . . . . . . . $23,000

SOURCE: National Aeronautics and Space Administration.

●

ciated rectenna and ground facilities to

collect and disperse electrical power to

the grid. The demonstrator requires a second generation shuttle and orbital transfer vehicle to provide the transportation

capabiIity to GEO.

Investment—$57.9 billion. By far the

largest percentage (57 percent) of the nonrecurring costs of the reference system are

devoted to this phase (table 13). In addition to providing for the transportation

and construction capabilities for the

space component, it also includes the

costs ($7.8 bill ion) for developing the terrestrial factories needed to produce satellite components.
94 ● Solar Power Satellites

Table 13.—SPS lnvestment—$57.9 Billion

Millions of Percent

dollars of total

Heavy lift launch vehicle . . . . . . . . $16,600 29

Development. ... ... ... ... .. .$10,500 18%

Fleet (6 boosters, 7 orbiters) ... $ 6,100 11 0

/0

Electric orbital transfer

Vehicle (21 x 284). . . . . . . . . . . . . 6,000

Construction bases . . . . . . . . . . . . 17,200 30

Development. ... ... ... ... ... $ 4,300 8 %

Hardware and launch ... ... .. .$12,900 22%.

SPS development . . . . . . . . . . . . . . 2,200 4

Ground-based factories

(klystrons, solar cells, etc.) . . . . . 7,800 13

Launch and recovery sites. . . . . . . 7,300 13

Program management and

integration. . . . . . . . . . . . . . . . . . . 800 1

Total. . . . . . . . . . . . . . . . . . . . . . . $57,900

SOURCE: National Aeronautics and Space Administration.

Though these are the best estimates currently

available, they suffer from an unavoidable

lack of specific engineering details, as well as

from insufficient manufacturing experience

for most of the system components. Moreover,

in some areas, (e. g., klystrons, slip ring, phase

control) current technology is inadequate to

define solutions to engineering problems.

Thus, the estimates could eventually turn out

to be high or low. The DOE SPS Cost Review68

examined five different elements of the SPS

reference design and concluded that the projected costs are “based on optimistic assessments of future technological and manufacturing capabilities. ”

●

●

Rectenna support construction. Projected

costs were found to be low by a factor of

3 to 5. Automated production might

reduce costs to a level more in keeping

with the reference system estimates, but

significant advances over today’s methods would be needed.

Graphite fiber-reinforced thermoplastic.

Currently used for golf clubs, fishing rods,

and for any other use where low weight

and high stiffness are required, this is the

recommended material for the satellite

truss work. The proposed structures are

insufficiently defined to specify the costs.

Estimates of future costs for the materials

‘*J. H. Crowley and E J. Ziegler, “Satellite Power Sy5tems (SPS)

Cost Review,” DOE/TIC-11190, MaV 1980

●

●

●

alone vary by a factor of 30 ($40 to

$1 ,250/kg).

Photovoltaic cells. GaAs cell cost estimates are extremely optimistic given the

current state of technology. Breakthroughs will be needed to reach the

design goals for mass, efficiency, and

costs. Silicon cell cost estimates are less

optimistic but will still require significant

simultaneous reductions in mass and cost

and an increase in efficiency to achieve

the SPS goal (2 g/W, $0.17/Wp, and 17-

percent efficiency).

Slip ring. It is not well enough defined to

appraise the slip ring components or their

operational capabiIity.

Satellite electrical systems. The degree of

detail is insufficient to judge the credibility of the cost estimates of the subsystem.

Thus, the $102.4 billion estimate of “front

end” costs and the $11.3 billion estimates for

each satellite may be an optimistic estimate of

SPS costs.

On the other hand, if unexpected breakthroughs were to occur in space transportation, rectenna or satellite technology, the costs

of the reference system could be lower than

now estimated. Since NASA estimates already

assume some technological breakthroughs

(e.g., in solar cell production, space construction, rectenna construction), they are more

likely to be low than high. In either case, the

estimates reflect a troublesome feature of the

reference system —the high costs that are necessary to demonstrate the feasibility of the SPS

(about $31 billion). A further $71 billion would

be needed to build and use a single reference

system satellite (investment of $57.9 billion

and a first satellite costing $13.1 billion).

Because the initial costs have a direct bearing

on financing the project, they are more fully

discussed in chapter 9.

A number of opportunities exist for reducing

SPS development expenses. Some involve pursuing alternative concepts; others, revising the

reference system. Because the reference system is by no means an optimal design, improvements could lead to significant cost

reductions. Common to all potential systems
Ch. 5—Alternative Systems for SPS ● 95

would be the division of SPS development into

the phases outlined above: research, engineering verification, demonstration, and investment, with increasing commitment of resources in each successive phase. For microwave and laser systems, space transportation

and construction would constitute a high percentage of the system costs in all phases. It is

in these areas that there would be a high

potential for reducing overall costs.

The precise costs of an SPS program would

also depend strongly on the nature and scope

of national and global interest in space. If

commercial ventures in space grow at a strong

enough rate (e. g., for telecommunications satellites, space manufacturing, etc.), the current

shuttle and its related technology would be inadequate, and pressures would be strong for

developing expanded space capabilities. The

explosive growth of the domestic airline industry since the 1930’s has been suggested as

the appropriate model to use to investigate

this eventuality. 69

Much of the technology and experience

needed for space construction (manned LEO

and GEO bases, large-scale antennas, studies

of space productivity, etc. ) and space transportation (manned and unmanned orbital-transfer

vehicles, shuttIe boosters, HLLVS, etc.) of SPS

would be developed for other programs as

well. Of these, the SPS program should bear

only its share. By charging only those costs

that are unique to SPS to the SPS program, its

front end costs would be reduced by a significant amount. Seen in this light, the massive

space capability needed for mounting an SPS

program would be less of an anomaly (given

the future evolution of space technology), ’”

and SPS would need to shoulder fewer of the

development costs for this capability.

There is also the possibility that a percentage of the investment phase could be shouldered by private investment, thereby reducing

the burden to taxpayers. This would be all the

more likely to happen in a milieu in which

“C, R. Woodcock, “Solar Power Satellites and the Evolution

of Space Technology, “ AIAA Annual Meeting, May 1980.

701 bid.

private investment in space is strong for other

reasons. Under these combined circumstances,

the total risk to the U.S. taxpayer would be

substantialIy reduced.

One interesting option for reducing transportation costs of a CEO SPS would be to

assemble the satellite in LEO and send it to

CEO under its own power. This might be

particularly applicable to the demonstration

phase of the reference program, since it would

avoid the need for premature investment in an

expensive manned geosynchronous construction/assembly facility.

Whatever their potential savings, all of these

possibilities could only be evaluated after the

proper scale of a demonstration satellite had

been determined. This decision, in turn, would

depend on considerable terrestrial and spacebased testing, some of which will take place in

other space programs (see ch. 5).

Because the HLLV would be used later on in

the production phase of the reference SPS absorbs the bulk of transportation costs, it is of

considerable interest to find less expensive

ways of transporting mass to space. Some of

the alternative high-capacity transportation

vehicles have been discussed earlier in this

chapter. The heavy Iift launch vehicles achieve

their cost reductions by economies of scale. It

has been suggested that smaller vehicles,

perhaps only slightly larger than the current

space shuttle, could be used instead of the

much larger HLLV.71 The smaller vehicles

would use higher launch frequencies to

achieve the same or better benefits. According

to this proposal, the minimum-cost individual

payload necessary to launch as many as five

reference SPS satellites to orbit is about 50

tonnes (compared to the Shuttle’s 30 tonnes).

The prospects for employing routine airlineIike launch practices opens a whole new approach to the logistics of major space manufacturing enterprises as well as providing

potential cost reductions for SPS.

“R. H Miller and D. L. Akin, “Logistics Costs of Solar Power

Satellites,” Space So/ar Power Review, VOI 1, pp. 191-208,1980.
96 ● Solar Power Satellites

ALTERNATIVE SYSTEMS

Systems other than the reference system

might be more or less costly, depending on factors such as the achievable efficiency, the

mass in orbit, and the state of development of

the alternative technologies that make up

these systems. At present, these alternatives

are much less defined and their costs accordingly even more uncertain than the reference

system costs. The following discussion summarizes available cost data and the greatest cost

uncertainties of the alternative systems.

●

●

●

The Solid-State System

The unit cost of the solid-state devices is unknown. However, the semiconductor industry has considerable experience in producing

large numbers of reliable solid-state components at low cost, and the learning curve

for such production is well-known. In principle, it should be possible to make a realistic

prediction of costs when the appropriate device or devices are well characterized.

Solid-state efficiencies. Present efficiencies

are much lower than for the klystron. Current research is aimed at increasing their

operating efficiency (to reach at least 85 percent).

Mass in space. Current estimates of the mass

per kilowatt of delivered power72 suggest

that the mass in space would be higher than

that of the reference system making the

transportation costs higher as well.

Since many components of the solid-state

system are shared with the reference system

(e.g., the graphite fiber reinforced thermoplastic support structures, the photovoltaic arrays, the rectenna design, etc.), it would be

possible to generate realistic relative costs if

the above uncertainties are reduced.

7

*G. Hanley, “Satellite Power Systems (SPS) Concept Definition Study,” vol. 1, Rockwell International SSD-8O-O1O8-I, October 1980.

The Laser System

The largest unknowns for the laser system

are the efficiency, specific mass and the cost

of the transmitting lasers themselves. This is

because the technology of high-power CW

lasers is in a relatively primitive state (current

CW lasers achieve outputs of 20 kw or greater,

operated in a so-called loop move, i.e., the

Iasant is recirculated). Space lasers for SPS

would have to operate at much higher outputs

(megawatts) and at higher efficiencies (i.e., 50

v. 20 percent) for current lasers. Concepts such

as the solar pumped laser and the free electron

laser are completely untried in a form that

would be appropriate to SPS. Therefore their

costs are even more difficult to ascertain. In

general it can be said that the cost of the

system would be tied to the overall efficiency

of the system and the amount of mass in

space, but considerable study and some development would be needed to make suitably

reliable projections.

●

●

●

Transportation. The laser systems that have

been explored project higher mass in orbit

than for the reference system, which may

drive the cost of the laser system up. However, if a substantial portion of this mass is

in LEO rather than in CEO, the overall transportation costs might not exceed the transportation costs of the reference system and

could turn out to be lower.

Demonstration. Because the laser system is

intrinsically smaller it should be possible to

mount a demonstration project for considerably less than for the reference system.

Terrestrial component. The ground stations

would have to have a certain amount of redundancy in order to accommodate laser

transmission when cloudy weather obscures

one or more receivers. The precise amount

of redundancy would depend on the particular location and would include extra transmission lines as well as extra ground

receivers.
Ch. 5—Alternative Systems for SPS ● 9 7

The Mirror System

Figure 25 summarizes mirror system cost

estimates for the SOLARES baseline case73

based on the DOE 1986 cost goals for photovoltaic cells. These “up front” cost estimates,

which include contingency and interest on the

borrowed money, lead to an estimated levelized busbar energy cost of 31 mills/kWehr

compared to 1990 estimated costs of nuclear/

coal mix of 45 mills/kWehr. I n comparison, a

strictly terrestrial system of photovoltaics pro73 et “Solar Energy Economics Revisited: The

Promise and Challenge of orbiting Reflector for World Energy

Supply, ” cit.

ducing the same overall output computed on

identical assumptions would cost 115

m i I Is/k Wehr.

Since electricity production from the mirror

system would depend heavily on the use of terrestrial solar photovoltaic or solar thermal

systems, cost variations of either conversion

system would have a strong effect on total

system costs. Figure 26 summarizes the effect

of varying several system parameters on the

cost of electricity delivered to the busbar in

the SOLARES system. The three most sensitive

parameters are solar cell efficiency, solar cell

cost per peak kilowatt and total space cost

Figure 25.—Elements and Costs, in 1977 Dollars, for the Baseline (photovoltaic

conversion, 4,146 km, inclined orbit) SOLARES System

Solar cells

NOTE: Total costs are proportional to the areas of the circles. Interest and contingency constitute 33 percent of the total SOLARES costs.

SOURCE: K. W. Billman, W. P. Gilbreath, and S. W. Bowen, “Space Reflector Technology and Its System Implications” AlAA paper 79-0545,

AIAA 15th Annual Meeting and Technical Display, 1979.
98 ● Solar Power Satellites

Figure 26.—Sensitivity of the SOLARES Mirror

System to Variations in System Parameters

% Variation of parameters

(transport, construction, mirrors in space). A

cost over-run of about 2 times (to $1,000/pk

kWe) could be tolerated before a busbar cost

of 45 milis/kWehr wouId be reached. Similarly,

a space system total cost over-run of a factor

of 4.25 could be tolerated. Finally, because of

the projected high energy production per unit

of mirror mass in space, a twenty-three-fold increase in space transport cost (or $1 ,380/kg)

would still result in a production cost of 45

mills/kWehr. For comparison, the charge for

transporting mass to space by means of the

space shuttle is estimated to be between $84

and $154 (1975 dollars). ”

74 National Aeronautics and Space Administration, “Space

Transportation Reimbursement Guide,” JSC-11-802, May 1980

SOURCE: Ken Billman, W. P. Gilbreath, and S. W. Bower, “Space Reflector

Technology and Its System Implications” AlAA paper 79-0545 AlAA

15th Annual Meeting and Technical Display, 1979,
Chapter 6

SPS IN CONTEXT
Contents

Page

Energy. . . . . . . . . . . . . . . . . . . . . . .......101

Introduction . . . . . . . . . . . . . . . . . . . . .. 101

Overview . . . . . . . . . . . . . . . .......,101

Determinants of Demand. . ..........102

Energy Supply Comparisons . . . . . . . ...104

Implications. . . . . . . . . . . . . . . . . . . . . .131

The Effects of SPS on Civilian Space

Poilcy and Programs . . . . . . . . . . . .135

Space Policy. . . . . .................135

Current and Projected Space Projects. . .137

Institutional Structures. . ............139

indirect Effects and ’’Spinoffs”. . ......139

LIST OF TABLES

Table No. Page

14. Criteria for Choice, , . ..............105

15. Characteristics of Five Electrical

Technologies.. . . .................110

Table No. Page

16.

17.

18.

19.

20.

21.

22.

23.

Description of Milestones of Major

Breeder Programs . ................116

Summary Assessment. . ..........,.125

Major Environmental Risks. . ........127

Terrestrial and Space Insolation

Compared. . . . . . . . . . . . . . . . . . . . . . .128

Terrestrial Insolation at Different

Latitudes and Climates . ............129

Costs of Onsite Photovltaics. . ......131

Range of Energy Demand in 2030,....132

Upper Range of SPS Use . ..,........135

LIST OF FIGURES

Figure No. Page

27 Recent and Projected Solar

Photovoitaic Prices. ., . . . + . . . . . . ...114

28 Levelized Lifecyle Cost of Electricity ..124

29 Quarttified Health Effects. . .........126
Chapter 6

SPS IN CONTEXT

ENERGY

Introduction

Because of its long development Ieadtime,

solar power satellites (SPS) will not be available to any extent before the early part of the

next century and will therefore do very little to

relieve our dependence on imported oil. SPS’s

primary use would be to replace old powerplants and meet any new demand for electricity. Consequently, the potential value of

the SPS must be determined in competition

with other future electricity sources and in the

context of U.S. and global electricity demand.

This chapter examines this topic in detail by

looking at the future demand for energy, and

electric power in particular, in the United

States, and the various supply options that

could compete with the SPS. Global energy demand and the SPS in a worldwide context is examined in chapter 7.

Overview

The U.S. energy future can be divided into

three time periods according to the supply options that will be available. These periods are

roughly the next 10 years (near term), from

1990 to approximately 2020 (the midterm or

transition period), and beyond 2020 (the long

term). Although these boundaries are not hard

and fast, they roughly define periods in which

particular energy supply forms will dominate.

Near Term

In the near term, there will be no significant

change from our current reliance on oil, natural gas, and coal. Currently about 92 percent of

our Nation’s energy supply comes from these

fuels. About one-quarter of the total is imported (almost all in the form of oil). Because

of finite suppIies, overalI consumption of these

liquid and gaseous fossil fuels must eventually

be reduced. However, the most important goal

over the next decade is the reduction of oil imports in order to avoid the severe economic

problems that would result from potential supply interruptions and to improve the U.S. trade

deficit. To do this, concentration must be

placed on lowering demand growth by increasing the efficiency of energy use, and switching

to the use of more abundant domestic fuels.

Of the two, improving energy efficiency will be

the major new source of energy because of the

much longer Ieadtime needed to bring on new

fuel supplies such as coal and nuclear. Domestic oil and natural gas can be developed

more quickly, but it is not likely that they will

contribute to reducing oil imports since both

will probably decline in production for the

decade. A recent OTA technical memorandum’ estimates a 25-to 45-percent drop in U.S.

oil production by 1990. Thte use of nuclear

energy will increase, but at a slower rate than

in the 1970’s. Finally, solar and biomass energy

production will grow rapidly during the 1980’s

but the absolute magnitude will be low compared to oil imports. Therefore, although an increase in the amount of coal, solar, biomass,

and possibly nuclear energy sources is expected, they will probably not be able to contribute enough by themselves to relieve the

pressures caused by U.S. dependence on imports.

Transition Period: Midterm

In the period from 1990 to 2020, substantial

supply shifts will occur. Although the period

will begin with heavy dependence on coal, oil,

and natural gas, it will end with a much greater

reliance on renewable and inexhaustible energy resources. U.S. dependence on imported oil

will almost surely come to an end if for no

other reason than that the availability of oil on

the world market will have dropped substantially. World oil production may drop as much

as 20 percent by 2000 and fall off sharply

thereafter. The dominant fuels during this

‘Office of Technology Assessment, U.S. Congress, “World

Petroleum Availability, 1980-2000,” technical memorandum, October 1980, OTA-T M-E-5

101
102 ● Solar Power Satellites

period are likely to be coal (for synthetic fuels,

direct combustion, and electricity generation),

natural gas, and possibly conventional nuclear. During this period, strong growth of renewable and inexhaustible sources such as

solar and biomass can be expected. Uranium is

a small enough resource that conventional

nuclear must be considered a transition energy

source. However, the supply of coal appears to

be substantial enough to play a major role well

into the 22d century. Whether these fuels contribute significantly beyond the midterm depends on the successful resolution of their

short- and long-term environmental and safety

questions.

It is also during this period that SPS and

other long-term candidates such as breeder reactors and perhaps fusion may begin to reach

commercial status. The transition period will

be the time when a number of long-term technologies will compete with one another for a

role in the future on the basis of economics

and public acceptance. This competition will

also depend heavily on the relative economic

efficiency of different ways of using energy, as

will be discussed below.

Long Term

In the long term, the United States and the

world will be almost totally fueled by inexhaustible energy sources. Although rapid

growth of sources such as the SPS during the

first decades of the century may be seen, it will

not be until the middle of the next century that

they could become as commonplace as coal,

electric, or even nuclear plants are today.

It is not clear which renewable and inexhaustible sources will dominate. It may be

that small-scale, onsite solar systems coupled

with an extremely energy-efficient economy

will be the ultimate future. It may also be that

a mix of technologies such as onsite solar,

biomass, fusion and/or SPS will be used.

However, the choice will be made in the transition period and will be based primarily on the

projected costs of competing supply systems

and demand technologies.

Determinants of Demand

SPS would fit most easily into a high electric

growth future. Such a future is contrary to recent low growth trends. In fact, many conservation initiatives have been directed at reducing the use of electricity because of the high

energy losses at powerplants. Nevertheless,

changes in relative fuel prices and gains in the

efficiency of electric generation and use could

dramatically change the picture.

The energy technology choices the United

States and the world will make in moving

through the three periods described above will

be primarily dictated, as always, by relative

costs. Until recently the dominant factor determining the development of energy technologies has been the type of resource and its

availability. The abundance of oil and natural

gas, and the ease with which it could be

transported and burned, dictated the development of most of the energy-using equipment currently in existence. Some of this

equipment could have been powered more efficiently by electricity, but this advantage was

often dwarfed by the cost advantage these

fuels had over electricity. However, many applications such as electric motors can be made

significantly more efficient, reducing the fixed

cost penalty.

In the past few years the relative prices of

these energy forms have changed because of

the rapid increase in oil and natural gas prices.

Current average electricity prices are about

twice that of oil and four times that of natural

gas. In 1960, the ratio of electricity to oil and

natural gas prices was 7 to 1. Even though the

costs of new powerplants are rising rapidly,

those of electricity will probably rise more

slowly than oil and natural gas, primarily

because of the relative abundance of coal and

uranium. It is even possible that synthetic fuels

from coal and biomass may be more expensive

than electricity from coal, particularly as

newer, more efficient coal combustion technologies are introduced.

The total cost to the energy user also includes the cost of the energy consuming equip-
Ch. 6—SPS in Context ● 103

ment. Electric powered equipment is often

cheaper than gas or oil fired counter parts.

This advantage will become increasingly important as the prices of oil and gas narrow the

gap with the price of electricity.

The implication of these effects is that electricity may become the cheapest energy form,

when both supply and demand are considered,

for many applications that could use a multiplicity of energy forms. The reason is that the

price differential between electricity and the

other energy forms (liquid and gaseous fuels,

direct solar, etc.) will likely be small enough

that it could be overcome by cheaper and

more efficient electric end-use technologies.

Some of these, such as heat pumps for space

and water heating, are already in use, while

others, such as inexpensive electrochemical

processes and long-life storage batteries, require further development, [f such development is successful and electricity does become

the cheapest energy form for most uses, then

electric demand growth could become quite

rapid even though total energy demand may

grow very slowly or not at all.

If this holds, solar power satellites will have

an easier market to penetrate than if the electric utilities continue their recent slow growth.

Thus, the fate of SPS rests as much on the ability to create energy efficient electrical end-use

technologies as it does on the relative economics of other electric generating technologies. One caveat must be added, however. If

demand technologies for fuels keep pace with

the efficiency improvements of electric demand technologies, such dramatic switching

may not occur.

Electric Demand Technologies

To see if such a future is technically possible

a closer look is taken at current and potential

uses of electricity. Because of electricity’s

unique properties it has been used for

specialized tasks such as lighting because of

the high temperature needed to excite the visible spectrum. Here, electrical energy is converted to visible electromagnetic radiation as

well as to heat. Nearly 60 percent of all electricity is used to perform mechanical work

through the use of motors. Electricity is also

used for industrial electrochemical processes

such as in aluminum and steel production, for

specialized induction-heating applications and

for microwave and infrared furnaces. A small

but crucial amount is used to power the Nation’s electronic systems. Finally, electricity is

used in the crudest form possible, namely for

direct conversion to heat.

Although these uses are more varied than for

the other major fuels, they account for less

than 12 percent of the total end-use energy demand in this country. The other 88 plus percent

is direct combustion to provide direct heat,

steam and mechanical drive. As indicated, for

electricity to penetrate this latter market it will

be necessary to make technical advances to

give electricity a cost advantage at the end-use

that can compensate for its higher cost at the

production point.

To do this requires making use of the special

character of electricity as an energy form.

Electricity is a high-quality fuel (thermodynamically work that is heat at infinite temperature). Therefore, it can be used for any

kind of mechanical work or it can be converted to heat at any temperature. The best

known example of the latter property is the

heat pump for space heating. This is now being

applied to water heating and certain drying applications with a substantial reduction in

energy use over electric resistance heating and

apparent cost advantages over solar.

In the industrial area, there is considerable

potential for increased use of electricity. For

instance, in steel making it can be used for the

plasma-arc process and direct-electrolytic reduction of iron. Although these processes have

been arourd for several years, technical development is still needed. In a nearer term application, the direct reheating of steel by high,

pulsed electric currents could result in a significant reduction in fuel use compared to

direct-fired processes, and also reduce material loss by eliminating oxide formation that

occurs with direct firing. In other areas advances have been seen recently in the efficiency of electric motors that are now competitive

with steam drives in many applications such as
104 Ž Solar Power Satellites

mechanical presses for metal forging. A more

speculative but very interesting area is the use

of laser or microwave radiation to drive industrial chemical reactions, instead of heat.

In ground transportation the principal problem is the development of long-lived, lightweight, reliable storage batteries. EIectric

drive using motors with precise solid-state

speed control can be made very efficient, as

has been demonstrated on many of the world’s

railroads. Advances have recently been made

in battery technology but the general feeling is

that “ideal” batteries are at least a decade

away.

The industrial sector is presently only 13-

percent electrified, while the transportation

sector only uses a negligible amount of electricity. Thus, these are the markets that electricity must penetrate to become the dominant

energy form. However, some new technologies

have the potential to reduce industrial demands without creating new markets for electricity. In the chemical industry, for instance,

biogenetic methods of feedstock synthesis

could replace thermochemical methods, reducing fuel usage without substituting electricity. About half the present industrial electric demand could be offset by cogeneration, a

technology that is not strictly a demand technology but which could nevertheless reduce

electricity needed from the grid. I n the transportation sector, battery research as a key to

electric vehicles must compete with the efficiency improvements possible with highmileage advanced vehicles using synthetic or

biomass-derived liquid fuels. The buildings

sector is already the most heavily electrified

and some electric technologies, such as common appliances, are nearing saturation.

The achievement of highly efficient, electric

demand technologies would change not only

the balance of fuels now used but also the sectoral usage patterns of electricity, with

dramatic growth in the industrial and transportation sectors, and less in the buildings sector

which has shown the greatest postwar growth

in electric demand.

Conclusion

It is likely that as technologies using electricity are improved or new efficient uses are

found, improvements will be made in using

other future nonelectric energy sources such

as biomass and direct solar. While all of these

developments are many years away, it is this

environment in which the SPS will compete.

The success or failure of these new electric

technologies will have a great deal to do with

determining whether or not a market exists for

SPS as well as the other large-scale, electricgenerating technologies.

Energy Supply Comparisons

Introduction

Comparisons with other energy technologies, both current and future, are a critical

part of assessing a proposed new energy technology. A host of criteria, only some of which

are readily quantifiable, is available for comparison purposes. Costs, environmental impacts, scale, complexity, versatility, safety,

and health risks are some of the more important factors of choice that ultimately determine the relative desirability of a given energy

technology. For technologies currently in

place these factors are generally well known.

For future technologies they are more often

only poorly known. Nevertheless, choices

among future energy technologies must be

made, either in the R&D phase, or, later, in the

marketplace.

Criteria for Choice

Whenever decisions to proceed with or halt

the development of a given technology are

made, it is important to lay out the framework

of choice, to develop a set of criteria by which

one may judge the relative benefits and drawbacks of different technologies. In addition to

providing a basis for choice, such a list can

also help to identify the essential distinctions

between technologies and highlight areas that

will need further R&D.

Table 14 lists 32 criteria developed in an

OTA workshop that are often used in compar-
Ch. 6—SPS in Context ● 105

Table 14.—Criteria for Choice

Plant description

1. Scale of power output (range in megawatts)

2. Power output in relation to load profile (baseload,

intermediate, peaking)

3. Versatility (other output besides electricity)

4. Complexity (high, medium, low) and maintenance

requirements (controllability)

5. Reliability (percent of time available to the grid)

6. Nominal capacity factor (percent time operating)

7. Material requirements

8. Labor requirements

9. Land requirements

10. Construction Ieadtime (years)

11. Lifetime (what are key determinants)

costs

12. Opportunity costs of RD&D (dollars and people)

13. Net energy ratio

14. Operating costs (cents/kWh)

15. Capital costs ($/kW)

16. T&D costs (cents/kWh)

17. “Decommissioning” costs

Impacts

18. Institutional (organization and ownership) impacts

19. Safety and health risks (magnitude and distribution)

20. Environmental risks (magnitude and distribution)

21. National security risks of normal or unintended use

22. Military vulnerability

Deployment consideration

23. Time period to commercialization

24. Geographic location; location of plant with respect to

load centers

25. Compatibility with other technologies and utility grid

Other

26. Probability for success (high, low, medium)

27. Initial demonstration requirements (large or small)

28. Resource constraints (domestic, international)

29. Risks/impacts of RD&D failure (chance it may become

prematurely obsolete)

30. Relative uncertainties to be resolved by RD&D (e.g.,

sensitivity of efficiency to design parameters)

31. Is it a viable example for rest of world?

32. Nature of R&D process (public, private, classified)

SOURCE: Office of Technology Assessment

ing electrical generating technologies. Most fit

into four broad categories: plant description,

costs, impacts, and deployment considerations. These criteria establish a context for

evaluating the SPS in relation to other future

energy technologies.

Five Future Energy Technologies

In the timeframe that the SPS would be most

likely to play a role in the U.S. energy future,

the other energy sources that are likely to

contribute wilI be predominantly the renewable and inexhaustible ones. OTA has chosen

to study the SPS in comparison to terrestrial

solar thermal technologies, terrestrial solar

photovoltaics, advanced fission (the breeder),

and fusion. If the health and safety problems

of coal are satisfactorily solved, it could also

be a major electric supply technology in the

period that SPS could become available. In addition, there may also be a component of conventional nuclear power still operating in the

second and third decades of the 21st century

(the timeframe after 2010 that is most likely for

SPS deployment).

The data that OTA generated for these technologies are supplemented by the electrical

supply comparisons which Argonne National

Laboratory made for the Department of

Energy (DOE/SPS) assessment program.3 DOE

chose to study conventional and advanced

coal technologies, light water reactors, liquid

metal fast breeder reactor (LMFBR) breeders

fusion, the reference system SPS, and terrestrial photovoltaics operating in a peaking

mode. Their data will be discussed along with

the results that OTA obtained. Coal and conventional nuclear power will be presented first

to provide a reference for the future energy

technologies in the discussions that follow.

THE COAL BENCHMARK

The coal resources of this country are

almost incomprehensibly large. Even if production were to triple, in that case coal would

serve about half the present U.S. energy needs,

known recoverable reserves would not be exhausted until late in the next century. Estimated additional reserves could take this

production well into the 22d century. Thus, for

all practical purposes, the supply of coal is inexhaustible.

Unlike any other long-term energy source,

coal can be exploited with known, proven

technology at costs that are competitive now.

Advanced coal technologies such as combined-cycle gasifiers and magnetohydrodynamics, are not vital to coal’s future but could

‘M E Samsa, “SPS and Alternative Technologies Cost and

Performance Evaluations, ” The Final Proceedings of the Solar

Power Sate//;te Program I?ev;ew, CON F-800491 (DOE), 1980.

‘Program A$$e$sment Report Statement of F;nd/ngs, SPS Concept and E valuation Program, DO F/E R-0085, 1980

83-316 0 - 81 - 8
106 ● Solar Power Satellites

improve the efficiency and economics of coalfired electric power. Thus, of all the options

for large-scale, long-term production of electricity, coal is the least uncertain technologically and economically and it is appropriate

to view it as a benchmark for evaluating the

others, including SPS.

Technological and economic criteria are not

the only alternatives to consider. Any energy

source must have generally acceptable health

and environmental impacts. Coal evokes depressing memories of scarred landscapes, suffering miners and smokey skies. Today, this

reputation is no longer deserved. Modern coal

mining and combustion techniques, when

properly applied, have reduced virtually all

these objectionable impacts to the point where

damage is clearly a small fraction of what it

once was.

The actual future of coal, however, is much

less certain than its potential. Issues arising

when expanded mining and use are considered

can be divided into three categories: interruptions, control costs, and risks. These will be

discussed in some detail because if coal does

not realize its potential, the reasons will probably be found here.

Interruptions are intermittent events that

prevent scheduled plans from being fulfilled.

Strikes by miners and transportation breakdowns are obvious examples. Opposition by intervenors that prevent facilities from being

built might be included here. These factors

can’t be completely eliminated, but proper

planning can reduce disruption. The major

long-term effect is to deter potential users

from turning to coal if they have other options

and are concerned about the reliability of the

coal supply.

The cost of controlling coal’s negative impacts is high. Reclaiming surface mined lands

and reducing the emissions of combustion

have received the most attention. For instance,

the Clean Air Act Amendments of 1977 have

required the use of the “best available control

technology” for limiting emissions of sulfur

oxides. Utilities have been concerned not only

because of the expense of the flue-gas scrubbers, but also because the equipment in use

has generally shown disappointing reliability.

However, current systems appear to be considerably better than early designs, so utilities

can, if they are careful, be confident that their

equipment will function reliably and effectively.

The regulatory approach has been to ensure

that the impacts are controlled to the point

where it is clear that known damages are

sharply reduced. As mentioned above, it appears that this goal has been achieved. As

more information is gained, it is possible that

control can be loosened without increasing the

risk. For instance, new data on the damage

caused by sulfur oxides and sulfates, and better data on the long range transport and chemical transformation of these and other pollutants might allow more selectivity in emissions

control. Thus, the costs of controlling impacts

may be reduced rather than increased in the

future. Such a reduction would improve coal’s

competitiveness with nuclear power or SPS,

unless some of the unproven risks are confirmed.

There are three major risks to long-term coal

combustion that could limit expansion or

make it much more expensive: public health

effects, acid rain, and carbon dioxide (C02

).

Coal combustion pollutants have been linked

by statistical analyses to tens of thousands of

deaths per year. These studies are highly controversial and have been neither proven nor

disproven. If they are generally accepted, considerable reduction of sulfur and nitrogen

oxides would probably be necessary. This

reduction would probably call for greater use

of coal cleaning before combustion, combustion modifications and higher efficiency fluegas desulfurization systems. Such changes

would be expensive but unavoidable if the

public demands cleaner air because of concerns over health risks.

The documentation for damage by acid rain

is better than for public health effects, but is

still not conclusive. Acid rain is evidently

caused by the same pollutants suspected in the

public health issue, but the scientific under-
Ch. 6—SPS in Context ● 107

standing of pollutant transport and chemical

conversion is poor. Furthermore, while acidification of certain lakes and streams is strongly

suspected, extensive damage to terrestrial ecosystems is only surmised. If this damage is

proved and found too costly, the remedy

would be the same as for public health effects.

However, it must be emphasized that proof of

damage is insufficient. The pollutants must be

traced back to their source in order to know

where to implement controls. Otherwise ineffectual or overly expensive control strategies

may be implemented.

The final risk, excessive CO2 released to the

atmosphere, is by far the most intractable. The

adverse impacts that have been suggested

dwarf those of any other human activities with

the possible exception of nuclear war, The C02

produced by burning fossil fuels and clearing

forests accumulates in the atmosphere. Some

of the CO2 that is produced is absorbed in the

oceans, but the dynamics of the CO2 balance

are not well-understood. The concentration in

the atmosphere is increasing by 5 percent per

year since 1958. C02 is transparent to most of

the incoming sunlight that warms the Earth.

Normally much of this is radiated back to

space in the form of infrared radiation, but

CO, tends to absorb and block this longer

wavelength radiation. This mechanism, the

greenhouse effect, is an essential ingredient in

maintaining the proper temperature balance

on the Earth. However, if sufficient quantities

of CO2 are added to the atmosphere, additional heat will be trapped to warm the Earth

significantly.

A number of studies of atmospheric CO2

levels predict that concentration will rise to

two to eight times today’s level in the 21st and

22d centuries. While there is continuing discussion about the effects of this buildup, the majority of the scientific community agrees that

the probability of global warming and other

climate changes is sufficiently high to warrant

exceptional attention.4 Changing climate patterns, even if they turned out to be ultimately

beneficial, would cause enormous disruption,

especially with agriculture. At least 10 years

4

0ffice of Technology Assessment, U S Congress, The Direct

Use of Coal, OTA-E-86, 1979

will be required before enough is known to

make intelligent decisions about the significance of the effects of increased CO2 in the

atmosphere. The contribution of fossil fuel

combustion to the CO2 buildup, the results of

this buildup on the heat balance and climate,

and the effects of climate changes must all be

studied extensively. At some point, however, it

may be necessary to limit coal combustion in

order to limit CO2 emissions since it is highly

unlikely that any practical means of removing

CO2 from the flue gases will be devised.

In summary, as far as we can tell now, coal is

capable of supplying most of the electric

power this country is likely to need for many

generations. The effects of the release of extra

CO, to the atmosphere are sufficiently in

doubt that other options must be prepared in

case they are required. However, until we

know that it constitutes a serious problem the

development of other options must be justified

on the basis that they will be cheaper or more

attractive in some other way than properly

control led coal.

CONVENTIONAL NUCLEAR

Conventional nuclear plants totaling 55,000

MW of power are now operational and another

106 reactors totaling 118,000 MW are either on

order or under construction.5 This is a substantial base for the nuclear technology, but it is

questionable whether it will be fully realized

or expanded because of public opposition,

licensing problems, financial uncertainties,

and eventualIy resource Iimitations.

Public opposition has been especially visible. While public opinion polls still show support for nuclear energy, this support has been

weakened for several reasons. Low-level radiation release and other problems with routine

operations contribute to public concern. Public support has also eroded because of continued lack of a suitable site and demonstrated

means for nuclear waste disposal. Further mishaps such as the accident at Three Mile Island

could condemn the technology in the eyes of

many who now reluctantly accept it. Finally,

‘Department of Energy, “U S Central Stations Nuclear Generating Units, r

’ September 1980
108 ● Solar Power Satellites

the possibility that nuclear energy could contribute to nuclear weapons proliferation disturbs many, though it is debatable whether

renunciation of the nuclear option by the

United States would materially reduce this

risk.

Most of these problems, except proliferation, can be ameliorated by improved technology, procedures, and regulations. But if improvements are not made quickly, public

opinion could swing against nuclear power in

the United States as it has on occasion in other

Western democracies (e.g., Sweden and Austria). Even if opponents remain in a minority,

they can find many opportunities to trouble

the industry through legal actions, regulatory

appeals and ballot initiative. None of these

may kill a particular project, but they could

discourage utility executives from choosing

the uncertainty and frustration associated with

nuclear power as long as they have other options such as coal.

Utility decisionmakers also have to consider

licensing and financial uncertainties. At present, many design criteria for nuclear plants are

so poorly defined that it is virtualIy impossible

to get a new reactor licensed. ’ This problem

may be resolved over the next few years, but

recent trends have not been reassuring. For instance, a review now underway—to determine

if fundamental changes in reactor designs are

necessary to contain melted fuel cores in case

of severe accidents— is expected to last several years.

Some regulatory rulemaking problems stem

from a lack of conclusive data. Others appear

to reflect the Nuclear Regulatory Commission’s lack of a clear picture of what it wants

to accomplish and how to do it. Both types of

uncertainties have to be resolved before the

utilities wiII consider ordering many more reactors.

Utility companies also face uncertainty concerning both the capital available to build

plants and the risk of a long-term shutdown.

The cost of a new nuclear plant is now close to

‘Office of Technology Assessment, U S Congress, Nuclear

Powerp/ant Standardlzat/on, OTA-E-1 34, April 1981

$2 billion. Not many utilities can raise that

much capital, even when the projected costs

of power at the busbar are favorable. Even

now, many plants are being built as joint ventures by several companies. A continuation of

high interest rates could delay many plans for

capital-intensive projects. And after an expensive reactor starts operation, the utility bears

an additional economic risk due to the possibility of unplanned shutdowns. The Three Mile

Island (TMI) accident and the Browns Ferry f ire

led to lengthy shutdowns that forced huge expenditures by the owner utilities, which then

had to generate or buy expensive replacement

power. The present financial difficulties of the

owner of Three Mile island, General Public

Utilities, illustrate how critical this concern

will be for other utilities.

Availability of fuel will eventually be a

serious constraint if conventional reactors are

used in the midterm to long-term future, without a shift to advanced nuclear breeders. The

Committee on Nuclear and Alternative Energy

Systems (CONAES) estimated that enough uranium exists in this country to fuel at least

400,000 MW for the lifetime of the reactors (40

years). ’ This would allow the construction of

another 227,000 MW of capacity. If ordering of

new reactors resumes in 1985 and continues at

the rate of 10 reactors per year, the last one

wouId be ordered in 2008. Because of retirements, by 2050 nuclear power would be back

to near its present level. Peak energy output

under this scenario would be about 5.6 (end

use) Quads in 2015. However, discovery rates

for uranium ore and imports and exports of

uranium could change the total availability in

an unpredictable way.

The greatest single long-term uncertainty

facing the industry is the future electricity

growth rate, just as it is for the SPS. Over the

next several decades, moderately high growth

rates might require much more nuclear power,

but as discussed in this chapter, the growth

rate may be more modest. However, low

growth need not preclude nuclear, and might

‘f nergy In Transition, Committee on Nuclear and Alternative

Energy Systems (CONAES), National Academy of Sciences,

VVashlngton, D C , 1979
Ch. 6—SPS in Context Ž 109

enhance the attractiveness of nuclear compared to other future central power options,

such as SPS, that require large deployments to

justify the development cost.

Nuclear energy can have a future if its problems are addressed effectively and decisively.

To some extent this is happening. The accident

at TM I has revealed weaknesses in reactor

plant design and operator training, to which

the industry and the NRC are responding with

initiatives such as the Institute for Nuclear

Power Operations and the Nuclear Safety

Analysis Center. As a result of the events in the

past 2 years, both regulators and utilities seem

more conscious that extreme safety is in everyone’s interest.

Whether these measures will ensure safety

in the future and enhance the industry’s public

image without pricing the technology out of

reach is still an open question.

FIVE FUTURE TECHNOLOGIES

The following discussion summarizes the

salient characteristics of the four central

renewable or inexhaustible energy technologies that have been chosen for comparison

with the SPS. While each of these alternatives

is compatible with centralized electricity production in a utility application, they are not

equally applicable for baseload power production. Photovoltaics and solar thermal sources

vary over the course of a day and the season in

a fashion that makes them well-suited for

peaking applications. Fusion, the breeder and

SPS would work most efficiently producing

constant power 24 hours per day, so they are

naturally suited for baseload power production. The applicability of photovoltaics and

solar thermal can be broadened to cover intermediate and possibly baseload applications

by the addition of storage capability, but over

the next 10 to 20 years there may be little

cause to do so, for two reasons. The first is that

the most cost-effective application of solar

thermal and photovoltaic systems is likely to

be as fuel savers until all the oil and gas-fired

generating facilities have been retired from

utility systems. Second, electric storage is far

more versatile and cost effective for a utility if

it is not restricted for use with a single plant. A

recent study by the National Academy of

Sciences’ concludes that when wind, photovoltaics, or solar thermal is used in a utility

system, “it is typically not desirable to have

dedicated storage but wiser to provide the

backup energy from the grid.” Except for a

small amount of storage to handle short-term

variations of sunlight in solar thermal applications, the conclusion that dedicated storage is

not appropriate for terrestrial renewable electric technologies is generally well-accepted.

Currently, electrical generation is fueled

largely by oil, natural gas, coal, fissionable

material, and stored water. For the time period

when the SPS is most likely to find applicability, there may not be as great a diversity of

energy supply technologies connected with the

utility grid as is now enjoyed; hence terrestrial

solar technologies may be used in a different

mode than the one that seems most desirable

now (i. e., peaking or intermediate). It is also

desirable to compare all the future electric

technologies on a common basis. For this

reason, OTA has prepared cost estimates for

solar thermal and photovoltaics operating in a

baseload mode. Because photovoltaics also

possess the unique property among these

future energy systems of being modular on a

very small scale, its use in a dispersed mode—

both connected to the electric grid and independent of it– will be discussed in a separate

section. In the future, it would be also worthwhile to compare SPS to an energy scenario

composed of a number of dispersed solar technologies working in complementary fashion.

The following discussion will give the major

characteristics, cost sensitivities and uncertainties, factors affecting deployment, and

foreseeable impacts of the different renewable

and inexhaustible energy sources. First, a short

summary of each technology will be given, followed by comparisons. Table 15 presents the

relevant characteristics of each of the 5 technologies in matrix form.

*“Energy Storage for Solar Applications,” Committee on Advanced Energy Storage Systems, National Academy of Sciences,

1981
110 ● Solar Power Satellites

Table 15.—Characteristics of Five Electrical Technologies

Criteria Fusion Breeder SPS Solar thermal Photovoltaics

Plant description

Scale of power

output

Power output in

relation to load

profile

Versatility

1-100 GW (lasers 10 kW to greater 10 kW-100 MW

smaller) than 100 MW

Base load Peaking, intermediate, Peaking, intermediate,

baseload (with stor- baseload (with storage

age, but expensive at expensive)

high-capacity factor)

Centralized, limited ver- Also cogeneration, Cogeneration?

500-1,500 MW

Baseload

500-1,500 MW

Baseload

Also large-scale, lowtemperature process

heat; synfuels; production of fissile

materials

Medium

Same as LWR (fuel

cycle reliability?)

Same as LWR

None

Like LWR

Same as LWR

Also large-scale, hightemperature process

heat; synfuels, production of fissile

materials

High

Between 0.6 and 0.75

satility. Some military

connection and

relevance to space

colonies and space

manufacturing

High

No good reason to

think it’s worse than

steam technologies.

Between 0.6 and 0.9

(laser-exception)

Between 0.6 and 0.9

high-temperature proc- -

ess heat

Complexity

Reliability

Low Lowest

Between 0.6 and 0.9, Greater than 0.9 ( = 1-

Iike other steam time for repair)

plants

Nominal capacity 0.6 to 0.75 Without storage: 0.2 to Without storage: 0.2 to

factor 0.25. With storage: UP 0.25. With storage: U P

to 0.9 to 0.9. Also depends

on region

Plentiful, domestic

materials, like nuclear

Material

requirements

Design specific, can

design around; stay

away from specialized

alloys

Like LWR

Can design around,

common material, sophisticated processing

Few and skilled for

space construction,

less skilled for receiver construction

Comparable to other

Plentiful, domestic

materials; need to

build manufacturing

industry

Moderate to large, decentralized largerLabor

requirements

Moderate to large,

decentralized larger

Land

requirements

Same as LWR. Less

than 1 acre/MW (including fuel cycle)

5 to 12 years?

5 to 10 acre/MW 10 acre/MW incremental addition could

be zero

Short; minimum 48

hours for 7 kW

Greater than 30 years

centralized solar

systems; 6.5

acres/MW or less

Construction 5 to 12 years (including Similar to other cenIeadtime

Lifetime

5 years for 1OO-MW

licensing) tralized technologies, plant

5 to 12 years

Greater than 30 years;

design like other

systems, but limited

experience

$40 billion to $100

billion to achieve first

operating satellite

2- to 20-year payback

Greater than 30 years

(first wall material)

Greater than 30 years

(replace steam

generator;

$10 billion to $15

billion (?)

l-year payback

1 to 2¢/kWh

$1,500 to $2,000/kW

Greater than 30 years

Costs of RD&D $20 Billion to $30

Unknown

Almost no fuel costs.

Same as LWR, but

less confidence

$2,000 to $2,500/kW;

Low $0.5 billion plus

$0.5 billion to $1.0

billion

1- to 2-year payback

$1 billion to $2 billion

Net energy

balance

Operating costs

2- to 20-year payback

0.3 to 1.5¢/kWh; low as

percentage of

delivered cost

$1,500 to $17,000/kW

1 to 4 percent of capital 1 percent; $20/kW/yr;

costs; $40 to less for centralized

$60/kW/yr

$1,500 to $3,000/kW $2,000 to $3,000/kW

(peak) ($1.60 to

$2.20/PW) (without

storage)

Centralized—same as Centralized—same as

other systems; decen- other systems; decentralized is negligible tralized is negligible

Capital costs

lower for a 5-GW plant

T&D costs Same as any central

system

Minor

Similar to present

institutional structure

Same as any central

system

Minor

Similar to present

institutional structure

Similar or greater than

other central systems

(reliability). Need to

consider outage problem

Push out of orbit. Small

at 4-percent discount

rate over 30 years

Decommissioning costs

Negligible Negligible

Impacts

Institutional impacts (ownership)Requires new management organization; international involvement possible

Decentralized— medi- Decentralized— medium to high impacts; urn to high impacts;

centralized— similar centralized— similar

to present infra- to present infrastructure structure
Ch. 6—SPS in Context ● 111

Table 15.—Characteristics of Five Electrical Technologies (continued)

Criteria Fusion Breeder SPS Solar thermal Photovoltaics

Safety and health Safer than PWR Fuel cycle? Same as Microwave bioeffects Small

risks PWR (higher power uncertain; ionizing Low; possible safety

density, lower radiation in GEO hazard with decentralpressure) ization in event of fire

Environmental Small for routine opera- Small for routine opera- Upper atmosphere ef- Small

risks tion tion fects uncertain

 Low possible manufacturing risk of PV

National security Designs other than Significant weapons Not efficient weapon None, possible benefits None, possible benefits

implications hybrid less significant Proliferation potential but transportation ca- of exporting benign of exporting benign

than breeder -

Military Same as any central

vuInerability ized powerplant

Deployment considerations

Time to commer- 30 years plus

cialization

Geographic Ioca- Low population area

tion with respect to load

centers

Compatibility Good

with other technologies and

utility grid

Other

Probability for Low to medium

commercial

success

Demonstration Large, but not as large

requirements as SPS

Resource None

constraints

Risks of RD&D High, but for next 10

failure years little risk, $20

billion

Relative High, complex

uncertainties

Is it a viable ex- Yes

ample for the

rest of the

world?

Nature of RD&D Magnetic—public;

process inertial —classified

pabilities significant technology are good technology are good

Same as LWR Slightly greater than Low Low

other central powerplants, depends on

space capability of

other nations

(Developed) 15 to 20 Long (greater than 20 Between 5 and 10 years Decentralized—5 years;

years domestic (Iicen- years) centralized— 10 years

sing)

Low population area Low population, no Decentralized—very Decentralized—very

water needed; mixed close; centralized— close; centralized—

S. W.-less than or S. W.-less than or

equal to other sys- equal to other systems. Geographic de- tems. Geographic dependence high pendence high

Good Penetration may be Iim- Goes down with higher Goes down with higher

ited to 20 percent.

Competes with other

technology. Nothing

obviously unsolvable

High Low to medium

Moderate cost for 500 Large cost (0.3 to 1

to 1,000 MW. About $1 GW)

billion

None Manageable

Technology is here, but High—big program;

public views regarding depends on program

waste? size (wait until HLLV

available)

Small High

Proliferation? for de- Yes, if t works

veloped countries

only?

Much public money Public funds for

spent, remainder RDD&T. Then private

might be private, but capital

for regulatory uncertainties

percentage penetration; negligible problems

High

Small (1OO-MW

aggregate of 2 to 3

demos)

Small

Negligible

Small (O&M costs)

Easier to digest in

small to moderate

chunks

Needs to be demonpercentage penetration; negligible

High

Small (community systems are medium)

Small

Negligible

Cell costs

Easier to digest in

small chunks; need

manufacturer capacity, but good example

Need not be demonstrated by Government strated by Governwith private partici- ment, large private

pation; industry will contribution

develop

SOURCE: Office of Technology Assessment.
112 ● Solar Power Satellites

1. Central Solar Thermal.– Solar thermal

technology is the oldest of the technologies

under study. It may also be the one that is

nearest to commercial application, since a

pilot plant is already under construction in this

country. The concept involves simply collecting concentrated solar radiation to heat a

working fluid in a central receiver (boiler),

which in turn drives a turbine to generate electricity. It has the versatility to provide either

electricity or process heat (steam) for industrial applications.

Two generic systems have been proposed for

the solar thermal approach: line-focus and

point-focus systems. In the line-focus scheme,

the Sun’s radiant heat is reflected and focused

by parabolic trough mirrors onto tubes containing the working fluid. The working fluid is

pumped to a central site where it may be used

to drive an irrigation pump, produce hot water

or steam for a factory, or produce a combination of heat and electricity for a small community. The line-focus approach is also

favored for process heat applications such as

enhanced oil recovery, but is not being actively considered by DOE for central electric

applications.

In the point-focus or “power tower” system,

a field of reflectors (called “heliostats”) is

focused on a central receiver atop a tower in

the center of the field. Although there are

several designs, a heliostat is basically a flat

reflective surface mounted on a computermonitored gimbal that allows it to automaticalIy track the Sun’s course across the sky. The

heliostat/power tower approach is being pursued by DOE as a central generating system,

though not exclusively so. * It can be used for

electrical generation either in a stand-alone

system or as a method for repowering existing

fossil-fueled power stations. The place of solar

thermal in a utility system —whether it serves

as a peaking, intermediate, or baseload unit—

depends on the storage capability of the solar

thermal plant. Without any auxiliary storage,

*In 1980, DOE initiated six major studies of the applications of

the power tower to a variety of industrial heat demands, ranging

from low-quality steam for uranium leaching to high-temperature steam for reforming methane to ammonia,

its effective capacity factor will be about 23

percent in a location such as the southwestern

United States. Addition of a modest amount of

storage (sufficient for 3 hours of extended

operation per day) will increase the capacity

factor to about 40 percent and make it possible for the plant to supply part of the lateafternoon electric consumption peak that occurs in many utilities. Because it is desirable to

smooth out the effects of short periods of

cloud cover, it is likely that the technology will

incorporate at least a small amount of thermal

storage (up to 1 hour). Solar thermal plants

could be made to operate in a baseload mode

with the addition of a large amount of storage,

but this increases the system’s conversion loses

and raises the overall cost per kilowatt installed. Solar thermal will, therefore, probably

be better suited for intermediate or peaking

uses since its daytime availability corresponds

closely with the peak of the electricity load

profile in many areas.

Solar thermal plants will be intermediate in

scale between today’s coal or nuclear plants

and small onsite generators. They can be expected to be deployed relatively quickly– perhaps within 5 years for a 100-MW plant.

The technical feasibility of solar thermal

technology is established. Engineering questions remain about the materials to be used in

the design of the central receiver. What is at

stake in making the technology commercially

viable is whether plants can be produced economically. The single most important factor is

the cost of heliostats, which accounts for

about one-half the cost of solar thermal designs. Present cost estimates range from $1,000

to $3,000/kW of capacity installed.

Much of this high cost reflects the cost of

materials. Savings realized from future automated production techniques are built into

these projections. Thus, the economic viability

of solar thermal technology depends on attaining heliostat cost goals.

The research, development, and demonstration (RD&D) costs associated with the solar

thermal development are expected to be in the

range of $0.5 billion to $1 billion. In addition
Ch. 6—SPS in Context ● 113

to continuing tests and studies to reduce heliostat costs, R&D for efficient and cost effective

storage methods, improved receiver designs

and transport fIuids are also needed.

2. Solar Photovoltaics. This technology is the

newest of the terrestrial solar options under

study and it is conceptually the simplest, since

it converts sunlight directly to electricity

without any working flu ids, boilers or generators. Because the essential element—a semiconductor wafer or “cell” — is modular at a

very small size, the technology has a versatility

in scale of deployment that surpasses any

other option. Photovoltaic (PV) cells have

already proved feasible in small-scale applications for both space and terrestrial purposes.

However, central PV systems have not been

tested yet, even in a pilot plant size. Because

the technology is so intrinsically modular, the

R&D program is not geared to the demonstration of a series of prototype plants but to the

improvement of the cost and performance

characteristics of the celIs.

A variety of different semiconductor materials is being developed for possible use in central PV systems. When sunlight falls on wafers

of these materials, it produces a direct current

of electricity. The efficiency of this process

depends on many semiconductor properties,

and how well those properties match the wavelength spectrum of sunlight. Typically, the

materials produce a direct current (DC) voltage

level of about 0.5 volts. Some of the more

promising PV developments include the four

technologies discussed below.

• The single cell silicon technology is the

most highly developed, and its introduction dates back 23 years to the beginning

of the National Aeronautics and Space

Administration (NASA) space program. Its

properties are well understood and cells

sold commercially for small-scale applications routinely achieve efficiencies of 10

to 13 percent; experimental cells have

achieved 15 percent and the theoretically

probable maximum is 20 to 22 percent.

The single most important barrier to commercial use is the high production cost,

●

●

●

even though costs have dropped and performance improved over the past decade

in line with DOE projections. Further cost

reductions to ($95/m2

) $0.70/peak watt)

and performance improvement to 13.5-

percent efficiency are the DOE goals for

1986.

The cadmium sulfide/copper sulfide technology is another approach that is commercialIy available and holds promise for

improvement. This material can be used

in thin films because of its high absorbance of sunlight, with a reduction in

fabrication costs and materials requirements. Experimental cells have achieved

efficiencies of 9 percent, with limited

lifetime. Improved cells have the potential for cost reductions to $10/m2 at 10-

percent efficiency. A number of other

cadmium sulfide technologies are under

study for thin film and standard cells.

The gallium arsenide technology is

another alternative that has achieved efficiencies up to 24.5 percent in experimental cells. The material can be fabricated in

thin films (with experimental efficiencies

to 15 percent) and can withstand concentrated sunlight at high temperatures. Its

major disadvantage is that commercial

production is still some time away and

costs remain much higher than for singlecrystal silicon.

The polycrstalline and amorphous silicon

technologies have the potential for orders

of magnitude cost reductions compared

to the single-crystal silicon technology,

but the experimental cell efficiencies

have so far only reached 9 to 10 percent.

(The probable maximum is estimated to

be at least 15 percent for the amorphous

technology in thin film cells.) These technologies are not limited to silicon, but are

currently being investigated along with

other novel materials concepts.

All the technologies discussed above are

candidates for use in flat-plate arrays of cells

that absorb unconcentrated sunlight. Gallium

arsenide is also an example of a high-efficiency material that can be used with a con-
174 ● Solar Power Satellites

centrating system. Concentrating systems involve different tradeoffs and are further from

commercial viability than flat-plate systems.

Both line- and point-focus collectors are under

consideration for PV concentrating systems.

Costs of concentrating systems can in principle

be low, since the receiving area needs only to

be covered with a thin reflective sheet, but the

technology is not developed enough to make

project ions yet.

Up to half the cost in a flat-plate design terrestrial solar photovoltaic plant today is for

the cells themselves. Other requirements for a

complete plant are materials for packaging

and supporting arrays of celIs, support structures, cabling to connect the arrays and

modules, and power conditioning equipment

to convert the DC voltage to alternative current compatible with the utility grid. About 300

cells would be combined into one panel, 30

panels into one array, and 10,000 arrays into

one module supplying 25 MW of peak power.

A central plant might produce 200 MW from 8

modules. Storage could be added to extend the

capacity factor of the plant, at additional

system cost. As discussed in the introduction

to this section, the economic merit of

dedicated storage for utility-based PV systems

has been seriously questioned.

The pace of technological breakthroughs in

PV technology is impressive. Today singlecrystal silicon cell arrays cost 15 percent of

what they did in 1974, as can be seen in figure

27. It is on further orders-of-magnitude cost

reductions that both terrestrial and SPS PV

systems depend. Such price reductions are

common in the semiconductor industry for

products with large markets (e.g., digital

watches, hand calculators, and now hand computers), but they are nearly unheard-of in the

energy industry. Therefore, planners familiar

with conventional thermal and nuclear energy

technology sometimes find them difficult to

accept. The goals for the DOE PV program are

Figure 27.— Recent and Projected Solar Photovoltaic Prices

30

5

n
Ch. 6—SPS in Context ● 115

for array prices of $2.80/peak watt in 1982,

$0.70 in 1986, and $0.15 to $0.40 in 1990 (all in

1980 dollars). At the 1990 level, complete systems are expected to cost $1.10 to $1 .80/peak

watt.

Although significant breakthroughs have occurred in the past 5 years, the principal thrust

of PV research is still directed toward the identification, selection, and engineering refinement of the cheapest possible semiconductor

materials. A concomitant part of this effort is

the development of suitable mass-production

techniques (now being most intensively pursued for single-crystal silicon and cadmium

sulfide) to open the way for mass market

penetration. It is upon the outcome of this

two-pronged effort (development of cells and

development of better manufacturing techniques) that the success of central terrestrial

PV plants will depend.

The time-scale for commercial readiness of

central terrestrial PV plants could be as short

as 5 years or as long as 15 years. The balance of

a central PV plant uses familiar building

materials and readily available power-handling

equipment. Once arrays are available, plant

construction Ieadtime should be short. According to the DOE program, commercial

readiness could occur in the early 1990’s. If the

RD&D program for PV cells is accelerated this

date could be earlier; on the other hand, slippage in the schedule for cell development

could delay commercial introduction.

Subsequent deployment of central PV systems would be paced by the rate of growth of

national manufacturing capacity for PV cells.

To achieve substantial penetration of central

PV in the time period of 1990 to 2010 will require an aggressive program for PV manufacturing plants. It is possible that decentralized PV centralized terrestrial and SPS

energy systems could all be competing for the

output of the PV industry during this period.

3. Advanced Fission (Breeder Reactor).– Conventional reactors use uranium ore very inefficiently because only a small fraction of the

uranium is tapped for energy. Natural uranium

consists of two isotopes 99.3 percent U-238

and 0.7 percent U-235. Only the U-235 is usable

directly in a conventional reactor. With conventional reactors, uranium resources would

be exhausted relatively rapidly by an expanding nuclear energy base. Breeder reactors on

the other hand, can extract 100 times as much

energy from a ton of uranium ore and thus extend the nuclear energy resource by several

centuries.

In a breeder, the core of the reactor is surrounded by a blanket of the type of uranium

not burnable in conventional nuclear plants.

This uranium captures neutrons escaping from

the chain reaction in the core and is transmuted into plutonium, a premium value

nuclear fuel. In this fashion, a breeder

“breeds” new fuel that is extracted from the

blanket, converted into fuel rods, and later

burned in the same or another reactor. An advanced breeder will produce about 10 percent

more fuel than it burns. A different fuel cycle

could use thorium in the blanket. Thorium is

an element similar to uranium, but it cannot be

used directly as a fuel. In the blanket, it

transmutes to U-233 which is a good fuel.

Breeders may also be distinguished by the

different types of coolants used to carry heat

from the core to the generating side of a

nuclear plant. Because the interconnections

between the core and the generators are quite

complex, requiring considerable engineering

refinement, the choice of coolant defines conceptually different types of breeders as much

as or more than the choice of fuel. Early in

its program, the United States emphasized

breeders with liquid metal (usually molten

sodium) coolants and the reactor concept that

evolved —the liquid metal fast breeder or

LMFBR– has become the reference system for

breeder research in other countries, representing more than 95 percent of the dolIar effort

devoted worldwide to breeders. Thirteen reactors using the LMFBR concept have been built,

the most successful being the French Phenix

reactor, and seven countries with major

breeder programs (table 16) have all emphasized the LMFBR type. Alternatives are helium

gas, molten salt coolants, and water.
116 ● Solar Power Satellites

Table 16.—Description of Milestones of Major Breeder Programs

Federal Republic

France of Germany Japan

Reactors

Rapsodie (24 MWt)

Phenix (250 MWe)

Super Phenix (1,200 MWe)

KNK-I (58 MWt)

KNK-11 (58 MWt)

SNR-300 (300 MWe)

SNR-2 (nominally 1,600 MWe)

1. 1960—GFK, Karlsruhe project

begins

2. 1964—Design study for 1,000 MWe

LMFBR

3. 1966—SNEAK startup

4. 1975—SNEAK experiments for SNR

300

5. 1967—INTERATOM F.R.G. and

BENELUX cooperation

begins

6. 1972—KNK-I goes critical

7.

8.

9.

10.

11.

12.

13.

14.

15.

16.

17.

18.

1976—KNK-11 goes critical

1969—SNR-300 safety report

1970—SNR-300 company established

1971—SNR-300 revised safety report

1972—SNR-300 sodium fuel pumps

tested

1973—SNR-300 construction begins

1974—SNR-300 steam generators

and IHX test

1975—SNR-300 specification of fuel

and cladding

1980—SNR-300 goes criticala

1974—SNR-2 company established

1976—SNR-2 preliminary designa

1981 —SNR-2 construction beginsa

Joyo (100 MWt)

Monju (300 MWe)

1. 1967-Joyo conceptual design

2. 1969—Joyo safety evaluation

3. 1970—Joyo construction begins

4. 1977—Joyo goes critical

5. 1968—Monju preliminary design

6. 1969—Monju conceptual design

7. 1973—Monju safety evaluation

8. 1978—Monju construction begins

-10. 1986—Demo plant begins

-11.1991 —Demo plant goes critical

-12. 1988—Commercial plant 1 construction begins

critical

-14.1991 —Commercial plant II construction begins

critical

as~h~d”l~ as of 197& In 1980, the SNR program currently in flux. SNR-301) designed but not yet licensed. SNR-2 not Yet designed. Entire Pro9ram will sli P substantially,

but the new schedule is not known at this time.

SOURCES: France: U.S. Energy Research and Development Administration, The LkfFBR Program In France, ERDA 76-14, March 1976; M. D. Chauvin, “The French

Breeder Reactor Program,” 1976.

Federal Republic of Germarty: U.S. Energy Research and Development Administration, The /_ J14FBR Program in Germany, ERDA 76-15, June 1976.

Jepem Report of Ad Hoc Study Committee organized by Japanese Government Science and Technology Agency, October 1977.

SOURCE: International Energy Associates Limited, 1980.

United Kingdom United States U.S.S.R.

Reactors

DFR (60 MWt) Clementine (25 kWt)

PFR (250 MWe) EBR-1 (1.2 kWt)

CFR (commercial size) Fermi (200 MWt)

EBR-11 (16.5 MWe)

Clinch River (375 MWe)

Fast Flux Test Facility

(equivalent of 160 MWe)

PLBR (commercial size)

CBR (commercial size)

1. 1953—first nuclear power program

begins

2. 1964—second nuclear power program begins

3. 1963—DFR goes critical

4. 1984-PFR construction begins

5. 1972—PFR goes critical

1. 1946—Clementine goes critical

2. 1951—EBR-1 goes critical

3. 1963—Fermi goes critical

4. 1966—Fermi shuts down

5. 1983 -EBR-II goes critical

6. 1971–SEFOR (U.S. and F. R. G.)

goes critical

BR-5 (10 MWt)

BOR-60 (60 MWt)

BN-350 (1 ,000 MW)

DN-600 (600 MWe)

1. 1958—BR-5 goes critical

2. 1965—BR-5 operates full core

3. 1969—BOR-60 goes critical

4. 1973—BN-350 goes critical

5. 1973—BN-600 construction begins

6. 1979—BN-600 goes critical

7. 1975—1,600 MWe reactor design

underway
Ch. 6—SPS in Context ● 1 1 7

Table 16.—Description of Milestones of Major Breeder Programs (continued)

United Kingdom United States - U.S.S.R.

aThi~ ~a~ the IJ,S, program in 1978, Currently there ,~ no planned pLBR schedule, penal Ing final ~eclsions on CRBR. CRBR iS “in Construction, ” but has been in a holding pattern for 2 years.

SOURCES: United Kingdom: Prepared by IEAL from compilation of U.K. documents.

United Statas: U.S. Energy Research and Development Administration, .LIquKI k4efa/ Fast Breeder Reactor Program, January 1977; U.S. Energy Research and

Development Administration, The LMFBR Program in France, ERDA 76-14, March 1976; Ford Foundation, Nuc/ear Power Issues and Choices: Report of the

AJuc/ear Energy Po/icy Study Group, 1977. Note on U.S. program: Items 9-15 refer to the program as it stood in April 1977, The plan and schedule has been in

revision since then, but it is not yet available.

U. S. S. R.: United States Nuclear Power Reactor Delegation, “Report of the ~Jnited States Nuclear Power Reactor Delegation Visit to the U. S. S. R,, June 1-13,

1975,” 1975.

SOURCE: International Energy Associates Limited, 1980.

As a source of centrally generated electricity, the breeder has been proven feasible at the

pilot plant scale and at an intermediate

scale but awaits demonstration at commercial

scale —that is the 1,000-MW size of new conventional reactors. Its operating characteristics are expected to be similar to a conventional (light water) reactor, except that it will

have higher thermal efficiency and therefore

less thermal pollution. Breeders may also in

principle be used for industrial process heat.

The Russian breeder BNR-600 produces electricity and desalinated water.

The technology was demonstrated at a pilot

plant scale in the United States in 1963, when a

10-MW reactor named EBR-II started producing electricity in Idaho. Between the 1960’s

and 1970’s, technical leadership shifted from

the United States to France. The Phenix which

has produced electricity for more than 5 years

at Marcoule, France, demonstrated successful

scaling from 10 to 250 MW, but suffered some

technical problems that required the plant to

shut down for more than a year. Its breeding

rate is considered too slow for commercial use,

and some components (especially steam generators) are not extrapolatable to commercial

size. France, together with the Federal

Republic of Germany and Italy, is now building a 1,250-MW reactor incorporating an improved design – Superphenix – at CreysMalville. Due to go critical in 1985, it will be

the first commercial prototype breeder.

The time until commercialization of the

breeder is 5 to 20 years depending on which

breeder technology (French or U. S.) is meant.

On the face of it, commercial readiness will

occur in 1985, assureing success of the Superphenix. After that, France plans an aggressive

program of breeder deployment, starting a new

plant every 2 years for the rest of the century. *

The French central utility (EdF) has already

ordered the first two of these “commercial”

plants. Progress on the U.S. plant comparable

to the Phenix (the Clinch River breeder) has

stalled, and its technology is outmoded in

some respects. Some argue this intermediate

plant step should be skipped to go to a commercial-size or nearly commercial-size plant.

———

*A reevaluation of these plans is apparently underway in

France following the recent election
118 ● Solar Power Satellites

The Ieadtime for constructing a conventional

nuclear plant in the United States is 12 years

and design and construction of a full-scale

breeder prototype under the same ground rules

could take 15 years. Thus, U.S. breeder technology could be commercialized sometime in

the 1990’s, depending on the development sequence.

The major difference between the French

and American technologies is whether the

reactor vessel uses a “loop” or “pool” method

of bathing the core with Iiquid sodium coolant.

The pool method is simpler, has more thermal

inertia, and is considered by the French to be

an added safety factor. The loop method is

more similar to conventional reactor technology and has been tested on an intermediatescale U.S. breeder used for fuel development

(the FFTF). Britain and France espouse the pool

approach; the United States and Japan use the

loop method; and the Soviet Union and the

Federal Republic of Germany are testing both.

In principle, a U.S. utility could order a

Superphenix reactor now for delivery in the

early 1990’s and in that sense the breeder

could be said to be commercially available

already. But no utility would invest in a central

nuclear plant without reasonable assurance it

would be reliable and could be Iicensed in this

country. The licensability of the French technology is an open question.

The RD&D cost of commercializing the

breeder is uncertain because the national

policy for 1976-80 was to not deploy the

breeder. It is also dependent on the demonstration strategy chosen (i. e., whether to go

straight to a commercial prototype). Estimates

made by the U.S. program managers in 1975 of

$10 billion to $15 billion for commercial demonstration should stilI apply.

The obstacles that the breeder program

must overcome before commercialization are

not primarily technical. There is little doubt

that a strong breeder RD&D effort could result

in a reactor that utilities could order in a few

decades. The questions are economic and institutional and generic to nuclear power. For

the purposes of this discussion, the economic

questions are less important. Unless the

breeder costs are so high that it is uneconomic

compared to other options, the major concerns

are related to light-water reactors. These will

not greatly affect the SPS decision.

Deployment of the breeder is predicated on

the continued expansion of light-water reactors. The problems facing the industry are

complex and difficult as discussed in the section on conventional nuclear reactors above. If

these problems are not resolved, the fission option will be foreclosed, at least as a major

energy source. Fusion may also be threatened.

The breeder exacerbates some of these problems. Proliferation of nuclear weapons will be

considerably harder to control if breeders are

worldwide articles of commerce. While this

might not have a direct bearing on a utility’s

decisionmaking process, the safeguards implemented to prevent diversion might be quite

onerous, and public opinion could be hostile.

Health and safety issues will be important

because of the plutonium and the operating

characteristics of the reactor. Waste disposal

will not be qualitatively different, but the vastly greater potential of breeders to produce

waste make the problem greater, especially if

disposal sites are difficult to find. While these

problems, individually or collectively, need

not be overwhelming, they can all adversely affect a utility’s inclination to order a nuclear

pIant. As long as a utility has a choice within a

reasonable economic range, it is likely to

select the less controversial options. Thus,

while breeders could in principle supply all the

electric power needed in the 21st century, they

may in fact supply Iittle or none.

4. Fusion.– Of the future energy sources

considered here as competitors to the SPS, fusion is the furthest from realization. Fusion

consists of nuclear reactions that are created

by bringing together light nuclei at speeds

great enough to exceed their mutual repulsive

force. The result of this reaction is the creation

of nuclear energy that is carried off by neutrons and/or charged particles, depending on

the nature of the reactants. In order to create

this reaction it is necessary to: 1 ) raise the

temperature of the fusion fuel to very high
Ch. 6—SPS in Context ● 119

levels and, 2) confine the fuel for sufficient

time. The criterion to be met by these two conditions is that more energy is released by the

nuclear reactions than is used to heat and confine the fuel that is in a wispy, gaseous form

(plasma).

Since the fusion reaction would be rapidly

cooled by the reactor walls, containment by

solid materials is not possible. Such an approach would quench the plasma. This difficulty, incidently, would also make a fusion

reactor easier to turn off, making it safer than

fission. Two alternate approaches are being

taken: using a magnetic field in one of many

possible shapes that have been proposed,

(magnetic fusion); and using a laser or ion

beam to produce a miniexplosion of the fuel in

solid form so that confinement occurs by the

inertia of the fuel (inertially confined fusion or

ICF). The second approach draws on nuclear

weapons work for some of its research and is

partially classified. The discussion to follow

will center on the magnetic approaches.

Among different magnetic confinement concepts—or types of “magnetic bottles” —the

leading contender is a toroidal shape called

the tokamak, after the Russian acronym given

by its inventors. As a reactor, it would be considerably more complex than a conventional

powerplant. The mixture of deuterium and

tritium fuel planned for use in first-generation

fusion reactors burns at a very high temperature, 100 million 0 C. The natural current in a

tokamak system is not sufficient for heating

the fuel that hot, so additional and complex

heating systems are required. The fusion core

will be large enough that electrical losses in

the magnets would be a significant drain on

the output of the plant, unless superconducting magnets are developed specifically for fusion applications. Other complexities arise

from the fuel requirements and operating requirements. Any fusion system must breed half

its fuel (the tritium component), and tokamak

systems currently under development must

operate in a pulsed (few hour) mode rather

than a continuous power mode.

These factors make fusion more complex

than either conventional reactors or breeders.

Particular difficulties in understanding the

behavior of the fusion fuel in its very hot

(plasma) state explain why scientists have had

so much difficulty making progress in fusion

research (which began in 1954).

Fusion is unique among future energy technologies because it has not yet been proven

technically feasible—that is to say, no controlled fusion reaction has yet operated in a

self-sustaining fashion or produced electricity

even on a small scale. It has a broad range of

potential applications, e.g., electricity production, high temperature process heat, synthetic

fuel production, and fissile fuel production.

The fusion community can point to a recent

string of successful experiments as evidence

that fusion is on the verge of a scientific

breakthrough. One of the goals is “breakeven, ” meaning the achievement of positive

net energy production. DOE expects breakeven to be achieved before 1985, and a recent

review by the research oversight board of

D O E

9 concluded that fusion was ready to

move from the research stage to the engineering development stage. Nevertheless, the

weaker understanding of the principles of controlled fusion compared to other energy technologies means that more emphasis is necessarily being placed on basic research. Consequently, the engineering-related considerations that influence commercial readiness and

acceptability—that is the technical, economic, and environmental factors — are more

uncertain than for breeders, solar thermal, PV

or SPS.

Despite the high degree of uncertainty,

much more can be said about the engineering

features of fusion than was possible a few

years ago, based on a set of thorough and

detailed engineering studies. Using the tokamak as a reference system, a powerplant is

likely to be in the range of 500 to 1,500 MW,

with 1,000 MW being the nominal planning

size. A tokamak fusion reactor would operate

as a baseload plant, with capacity factors, construction Ieadtimes, plant lifetimes, land,

labor, and materials requirements similar to

9ERAB Report (DOE), 1980
120 • Solar Power Satellites

conventional nuclear plants. The high-technology core would constitute a substantially

larger percentage of the total plant than for

conventional (or breeder) nuclear plants, and

fusion would have some unusual maintenance

problems that arise from the character of the

fusion reaction itself. Since the nature of the

fusion core must be considered hypothetical

until technical feasibility is proven, the economics of fusion is perhaps the most uncertain

characteristic at this time. Two different engineering studies prepared at the University of

Wisconsin10 and Argonne National Laboratory” put the busbar costs at 75 and 44 mills/

kW respectively (in 1980 dollars).

Because of the special character of fusion,

estimates of the timetable to commercial readiness vary widely. A recent survey of opinion

found the majority of estimates to fall between 2000 and 2025, with some as early as

1990 and a few extending to the 22d century or

never. 2

It appears unlikely that fusion will be

commercialized before 2010— the earliest IikeIy date for SPS – and the present DOE program

is on a schedule calling for “demonstration” in

2015, with the dates 1995 or 2000 considered

possible at increased cost. The DOE program

calls for two steps after breakeven in 1985, the

first a fusion engineering demonstration in

1990 that produces thermal power but no electricity. Pending success with this plant, a fusion demonstration plant would be started by

about 2000, that could produce 500 to 1,000

MW of electricity. However, more steps are

likely to be needed prior to commercialization. Fusion research is in such an early phase

vis-a-vis other technologies that it is difficult to

determine reliably the path to “commercial”

fusion.

To be commercialized, fusion must also find

public acceptability. From an environmental,

health, and safety standpoint, the principle advantage of fusion over fission power is that

‘

O

’’ NUWMAK A Tokamak Reactor Design Study, ” Fusion Englneerlng Program, Nuclear Engineering Department, University

of Wisconsin UWFDM-330, March 1979

1

‘Argonne National Laboratory, Start;re

“’’Chase Delphi Study on Fusion, First Round Results, ” Chase

Manhattan Bank, September 1979

there is no conceivable possibility of a runaway reaction. But first-generation fusion

plants will use relatively large quantities of

tritium, a radioactive gas harmful to humans.

Advanced fusion fuel cycles would greatly

reduce the quantity of tritium that must be

handled. To make fusion safe, the problem of

handling industrial quantities of tritium without routine small emissions will have to be

solved. There will also be a substantial waste

disposal problem, because the “first wall” of

the containment chamber for magnetic systems will have to be replaced every few years

due to radiation damage. Since the replaceable “wall” may be up to 1-m thick, the quantity of waste could be high, measured in the tens

or hundreds of tons per reactor per year. This

material will be highly radioactive and wilI present a long-term waste disposal problem,

though the radioactivity will not be as longIived as conventional fission reactor wastes.

The amount and lifetime of radioactive

material can possibly be reduced substantially

by using other materials for the first wall

without changing the nature of the fusion reaction. Analogous changes for fission reactors

are not possible since the waste material

generated is an inherent part of the fuel element. Finally, fusion carries some proliferation

risk because the energetic neutrons of the fusion reaction comprise a high quality source

for producing weapons material. It is conceivable that unless proper safeguards are

developed, a world full of fusion reactors

could be highly proliferation prone. However,

there are many other technologies that are

available or could be available for the same

purposes earlier, more readily, and more

cheaply than fusion.

To a degree, fusion may also inherit the

public acceptance problems of nuclear fission.

Fusion is a different technology, with fewer intrinsic risks but greatly increased complexity.

But since it is a nuclear technology, even if it

turns out to be relatively benign compared to

fission, it may remain associated with conventional nuclear power in the public mind.

The greatest uncertainty in the development

of fusion remains the physics associated with
Ch. 6—SPS in Context • 121

breakeven. Although many of these uncertainties can be resolved by small experiments

costing on the order of $1 million to $10

million, complete resolution will still require a

few large sophisticated experiments, costing in

excess of $1 billion. It should be noted,

however, that the nature of the fusion reactioc

is such that a demonstration reactor wouId require very little increase in scale or cost from

these large experiments. The total cost to develop fusion to the stage of commercial

viability depends significantly on the cost of

this “hardware” and is projected by DOE to be

$20 billion to $30 billion. If more than two major steps are needed before a commercial prototype can be built, the cost will be somewhat

higher.

5. Comparisons of Central Electrics. -Because

each of these future electric technologies is

designed for use in a central plant mode, they

are best compared in the context of a utility

company’s needs. If each of the different technologies were at the same stage of development, comparison based on projected power

costs would be the most powerful and appropriate method of analysis, particularly if all

were close to commercial maturity. But the

five are at quite different states of technical

maturity — so much so that even the definitions used for “commercial” maturity used in

the different programs may be qualitatively

different. Lacking information that may take 5

to 20 years to acquire, a close look was taken

at other characteristics, with particular attention to properties–such as complexity, health

effects, and safety — which past experience has

shown to be closely related to both capital and

operating costs<

After costs, the most important issue the

utilities must consider in deciding to risk

capital on a particular investment in a generating technology is the way in which a plant is

expected to function and its associated impacts. Can the proposed technology be successfully integrated in the grid and meet the

associated requirements for reliability and

capacity? These issues are discussed for the

SPS in chapter 9. This section will highlight the

factors most important for the other central

base load technologies.

Scale of Power Output. – Plants must be

designed on a scale that can be readily integrated into the existing grid at the time of deployment. Using the rule of thumb that no one

plant should comprise more than 10 to 12 percent of the system’s capacity to guarantee integrity of the grid during a plant failure, the

largest plant that could be presently accommodated by a single utility in the United States

would be 2,500 MW, and that only by the Tennessee Valley Authority. (See ch. 9. for a

discussion of this issue.) Cooperative agreements among utiIities on the same grid can expand the maximum acceptable size. Current

baseload plants generate from 500 to 1,300

MW. Both fusion and breeder plants are planned to fit closely within this range. Very large

powerplants (greater than 1,500 MW) were the

rule in fusion planning several years ago, but

encouraging new research results coupled with

new interest in smaller powerplants allowed

fusion engineering designers to direct efforts

toward conceptual designs in line with present

powerplant scales. Larger plants would mean

improved economies of scale for the breeder

(as it would for fusion), but for utility compatibility reasons (as well as licensability), the

projected size of the breeder has also been

kept below 1,500 MW.

Solar thermal and solar PV pIants achieve

their economies of scale at much lower outputs–100 to 200 MW maximum. Both can

function economically at still smaller scales.

Photovoltaics are modular and economic at a

few kilowatts or less.

Only the reference system SPS appears to

have economies of scale that make it impractical at a size that can be accommodated by

the present utility systems. Whether it could be

accommodated in future utility systems depends on the growth of future electric demand. Smaller microwave systems or a laser

system would fit the utility grid more readily.

Reliability and Capacity Factor. – Prior to

the demonstration of a technology, both its

83-316 0 - 81 - 9
122 ● Solar Power Satellites

capacity factor and its projected reliability are

subject to considerable uncertainty. However,

it is expected that breeders will operate much

as conventional light water reactors do today,

with capacity factors of 60 to 75 percent and

forced outage rates (that is, unplanned shutdowns) of less than 15 percent.

The steam and electric generation parts of

fusion plants are expected to be similar to conventional reactors and breeders. But the fusion

core will be much more complex than the

nuclear parts of a conventional or breeder

plant. One indication of this is that the fusion

core is expected to represent a much larger

fraction of the plant investment (50 v. 10 percent for nuclear). Because of the vast uncertainties surrounding the actual operating

characteristics of fusion technology, it is impossible to predict what capacity factors and

forced outage rates are likely to be. It is clear

that to compete with breeders or light water

reactors, fusion should be just as reliable and

capable as they are.

Solar thermal is a steam technology, with a

balance of plant that will be similar to, though

smaller than, that for a conventional baseload

plant. The solar-thermal part will be chiefly

vulnerable to failure of the heliostats or the

boiler. The heliostat fields could have tracking

or maintenance problems, the boilers could

have materials and integrity problems due to

the high solar flux. Nevertheless, it is projected

to operate with reliability similar to other

steam technologies —60 to 90 percent.

Solar PV is the simplest technology, without

steam systems or moving parts or (necessarily)

high solar flux, if flat plate systems prove most

economic. Because it is simple, the reliability

of solar PV is expected to be very high (greater

than 90 percent). There may be unsuspected

durability problems with some solar PV cells,

however. Although PV are an intrinsically simple technology, it currently has higher material

and manufacturing costs than other alternatives. Both solar thermal and solar PV have

an inherent limitation of plant capacity factor,

due to the daily and yearly variation of ambient sunlight, which differs with latitude and

climate. In the Southwestern United States, the

capacity factor of a plant without storage

would be 23 to 25 percent. Storage for a solar

thermal or solar PV plant redistributes the collected energy to other times of day, but does

not appreciably change the amount of energy

CoIIected per year per acre of plant area.

The SPS would circumvent the 25-percent

capacity factor limitation of terrestrial solar

plants by being exposed in space to direct

sunlight 24 hours per day all year (except for

brief, predictable eclipses if located in geostationary orbit, or unpredictable cloud cover if a

laser or mirror system). The question with SPS

is not solar capacity but availability. As with

fusion, it is impossible to predict just how

reliable the SPS wouId be. As a system it is very

complicated, involving a massive transportation system, untried satellite technology, and

large ground systems. Reliability factors as

high as 95 percent have been predicted for the

operation of the satellite and rectenna combined, 13 but they have not taken into account

the entire SPS system, including maintenance

and repair. Research on transportation and

space platforms will provide considerable insight into the expected reliability of the

satelIite.

Complexity. –Given the extreme range of

physical requirements for a sustained, controlled fusion reaction, fusion is clearly the

most complex technology under consideration, requiring a plasma hotter than the core of

the Sun, powerful large superconducting

magnets bigger than any yet built, and

materials problems in a radiation environment

more severe than that of the breeder. The

reference system SPS is less complex than fusion, since it uses more nearly proven technologies. Nevertheless, the overall engineering

and logistics problems of the SPS could make

it an undertaking that approaches the complexity of fusion when all the technical hurdles

are considered. It should be noted, for in-

‘” SPS/Utlllty Grid Operations, ” sec 14 of Boeing Corp , report No D 180-25461-3
Ch. 6—SPS in Context Ž 123

stance, that the SPS as it is described in the

reference system could only begin to be

assembled as a system after major breakthroughs in two other technologies—space

transportation and PV — are achieved.

The breeder is considerably less complex

than either the SPS or fusion, but is more complex than conventional nuclear systems. The

main potential difficulties are the nuclear

properties of the breeder core, the peculiarities of the liquid metal coolant, and the potential difficulties of the breeder fuel cycle.

Although these factors are incremental additions to the complexity of a nuclear pIant, they

are the driving factors behind the projections

that the breeder will cost 25 to 100 percent

more than a light water reactor (LWR).

The solar thermal plant is also a steam

system that has much of the complexity of

other steam systems, such as coal or nuclear,

mitigated by the reduced size of the plant and

the modularity of the heliostat field. There

may be special problems in having a central

plant boiler at the top of a tall tower, but solar

thermal plants appear to be less complex than

nuclear, fusion or SPS technologies. Their complexity may be comparable to current baseIoad coal technologies.

Central PV plants have by far the least complexity of the alternatives discussed here, for

two reasons. First, the basic technology is simple, modular, and should be manufactured

cheaply if the experience with mass-produced

semiconductor products holds as expected.

Second, the additional technology needed for

a central plant is electrical rather than mechanical or thermal, and is already proven at

the appropriate scale.

Costs. –The cheapest acceptable technologies available in any future time period will

be the ones deployed, so cost is the most important — and most problematic —factor. Two

aspects of technology cost will be discussed.

The busbar cost is the cost at which truly commercial versions of the various electric technologies will produce power. The opportunity

cost is the total cost of RD&D for a technology

from inception through the construction of a

commercial prototype pIant. It is the cost of

lost opportunities in other areas for which the

money could have been spent. A component

of the opportunity cost is the cost of the commercial prototype itself, which is the demonstration cost.

The busbar cost is the actual cost of producing electricity with a technology when capital

costs, fuel costs (if any) and operation and

maintenance costs have been considered. For

current technologies, these costs are wellknown and therefore detailed comparisons between technologies are possible. However,

even for current technologies the task can be

difficult–witness the debate over whether

coal or conventional nuclear is cheaper. For

future technologies, the task is much more uncertain. Therefore, cost estimates of delivered

electricity are of Iittle use in deciding between

technologies in early development stages. Furthermore, technologies reach commercialization at different times. Therefore, cost estimates for one technology are more reliable

than for another, with the most fully developed technologies having the most thoroughly tested cost data. For example, coal

plant costs are well known, but breeder costs

are less so, and fusion costs are much less so.

Though it is a current technology, the future

costs of PV for onsite, central, or SPS plants,

depend strongly on the future costs and efficiencies of PV cells and are consequently uncertain as well. A final note on busbar cost estimates is that as a technology matures, the

projected cost may fall (as has happened with

computers) but much more often rises. The

maturation effect of costs during R&D has

been particularly borne out in aerospace and

energy technologies.14 15

Although busbar cost estimates are useful in

the research phase to identify cost sensitivities

and indicate preferred research directions to

reduce costs, they become crucial at the

“U S General Accounting office, “Need for Improved

Reporting and Cost Estimating on Major Unmanned Satellite

l’roject~, ” PSAD-75-190, 1975.

“F W Merrow, S W Chapel, and C Worthing, “A Revtew of

(-ost E ~tlmatlon in New Technologies Impllcatlons for Energy

I’recess Plants, ” R-2481-DOE, Rand Corp , 1979
124 ● Solar Power Satellites

deployment phase. The DOE prepared cost

estimates for coal, light water reactors, coal

gasification systems using combined cycle

systems, LMFBR breeders, peaking terrestrial

PV plants, fusion and the SPS (fig. 28). ” The

figure indicates the high and low ends of the

range of estimates for each technology in

2000. It shows that capital costs do indeed increase with complexity, rising steadily for coal,

LWR, LMFBR, fusion, and SPS systems. Costs

are also relatively high for the terrestrial PV.

Although it is an unlikely circumstance, the

chart indicates that alI could cost the same in

2000.

OTA prepared estimates that considered

these future electric technologies including fusion (but not combined cycles), in terms of

their busbar costs in 2010. The resuIts are given

in table 17, using common financial considerations, equal capacity factors (65 percent in

“Program Assessment Report statement of findings, SPS Concept and Evaluation Program, DOE/E R-0085, 1980

Figure 28.—Levelized Lifecycle Cost of Electricity

Levelized generation cost (1978 mills/kWh)

SOURCE: Program Assessment Report Statement of Findings, SPS Concept and Evaluation Program, DOE/E R-0085, 1980.

all cases), and the assumption of baseload

operation for each technology. As noted

above, these numbers may be indicative but

are Iimited in their use because the uncertainty

range represented by the range of costs means

different things for each different technology.

Factors that are small contributors to the

estimated costs may have uncertainties that

are substantial (such as nuclear waste disposal

costs) but are difficult to identify and measure.

Finally, baseload operation is not necessarily

the most attractive operating mode for solar

thermal and solar PV though it provides a basis

for comparison.

RD&D Costs. –One of the most difficult

tasks in choosing the wisest course for RD&D is

to maintain the proper balance between the

risks and the potential payoffs associated with

a particular line of research. The goal is to

minimize the risk and maximize the payoff. In

energy research, the risk is associated with the

expenditure of RD&D funds for a project that

could conceivably fail. The hoped-for payoff is

cheap energy. The associated RD&D funds required to pursue some of the future electric

options under consideration are so great that it

is Iikely that not al I can be pursued at an optimum rate. By according priority to some, opportunities for payoffs from others will be

foregone.

As the matrix of table 16 makes clear, SPS

wiII have the highest front-end costs by a considerable margin, followed by fusion and the

breeder. The solar thermal and solar PV systems will have lower RD&D costs, in the range

of $0.5 biIIion to $2 billion.

The costs of the breeder will be large–in

the range of $10 billion to $15 billion—

assuming the United States does not change

the present policy of developing domestic

rather than foreign technology. But this figure

is nevertheless comparable to the front end

costs of other centralized energy technologies.

Cumulative RD&D for light water reactors, for

instance, is estimated to have total led $10

billion. Fusion’s costs will be the same or

somewhat higher, estimated at $20 billion to

$30 billion, including a commercial prototype
Ch. 6—SPS in Context ● 1 2 5

Table 17.—Summary Assessment

Prospective

economic-cost Relative Commercial

range a (1 980 $) environmental Engineering/ readiness

Technology (mills per kWh) costs Scientific technical Commercial (year)

Satellite power system . . . . . . . 80-440 Unknown Provenb Unproven — 2005-2015

Solar photovoltaic with storage 65-86 Negligible Proven Proven Unproven Late 1980’s

Solar thermal with storage. . . . 62-89 Negligible Proven Proven ● Unproven Late 1980’s

Breeder reactors . . . . . . . . . . . . 58-73 Substantial Proven Proven Proven 2000

Fusion . . . . . . . . . . . . . . . . . . . . 44-75C Moderate- Unproven — — ?

substantial

LWR-201O . . . . . . . . . . . . . . . . . . 58 Moderate- Proven – Proven Proven Operational

substantial

LWR-1980 . . . . . . . . . . . . . . . . . . 47 — — — — —

aPlant starting in 2010.

bEnvironmental impact still unknown, other aspects generallY accepted.

CNote this range reflects differences between two studies’ estimates (footnotes 1 Cl and 11 On p 120).

aMassive scale-up of known technologies.

SOURCE: OTA working paper.

plant. Fusion and the breeder may thus compete with each other for R&D funds.

The costs of the SPS will be substantially

higher than for any of the other options, at an

estimated figure of $40 biIIion to $100 bilIion. 7

The high number assumes all space development and pIant investment costs are allocated

to the SPS (see ch. 5), while the lower number

assumes the total cost but allocates $60 bill ion

to other space programs that could benefit

from the same technical capability.

The SPS RD&D cost is so high that commitment to it could foreclose fusion or the

breeder. As such, a decision at some point in

the future to commit to the SPS would be a

decision with potentially far-reaching consequences.

In fact, the SPS is the first proposed energy

option whose RD&D costs enter the budgetary

range that has previously been limited to very

high-technology, high-cost national defense

programs such as the MX missile system. That

system, as proposed, will cost” $34 billion to

$50 billion. Thus, from a policy point of view,

the SPS is qualitatively different from any

other proposed long-range energy solution.

Institutional Impacts. — Neither fusion nor

fission requires much that is new institutionally because their size, health and environ men170TA Workshop on Technical OptIons, December 1979

tal impacts, and operating structure are similar

to current LWR technology. As technologies

used in the centralized mode, the solar technologies will not require different institutional

attention than do any other peaking or intermediate plant. As dispersed plants, they are

likely to be subject to a much different regulatory regime’ 8

and utility structure that encompasses a much broader technological scope

than is now the case.

SPS, however, because it is a space system

requiring very high capital investment, would

likely involve an institutional structure very

unlike those in use today in the utility industry

(see ch. 9). The main point is that the utilities

are unlikely to want to invest directly in

satellites, or perhaps even rectennas. It will

create far fewer regulatory and capital problems for the utilities for them to buy power

from a single SPS corporation and incorporate

It directly into their grid. A national S P S

monopoly would necessarily be federally, as

welI as internationally regulated (see ch. 7).

National Security Risks. – Both of the nuc I ear technologies u rider consideration

(breeders and fusion) can be used to generate

weapons material and therefore they carry

some risk of increasing nuclear weapons proliferation. The terrestrial solar technologies

—.—

“Office of Technology Assessmentr U.S. Congress,

“Decentralized Electric Energy Generation Systems,” upcoming

report, fal I 1981
126 • Solar Power Satellites

seem to have purely beneficial national security effects, however. They can be exported and

used around the world for peaceful purposes.

Because they would be used in relatively small

units, they would be much less vulnerable than

any larger unit and less of a military risk for a

country selling the technology.

SPS would have indirect military potential,

largely from the technology that would be

developed for space transportation and space

construction. However, the system itself would

serve as a poor weapon. The question of vulnerability of an SPS system to nuclear or other

attack is a different issue. On the whole it is Iittle more vulnerable than any of the larger terrestrial electricity options (see ch. 7).

Economic Risks of RD&D Failure.— In

general, the risks of failure are tied directly to

the opportunity costs for the different central

electric technologies. Therefore, the risks are

higher for fusion and SPS than for any of the

others. However, the financial risks of failure

may be mitigated if some of the RD&D costs

are recoverable for other uses. For example,

the space spinoffs from developing the SPS

could be significant (an upgraded shuttle,

space platform technology, an orbital transfer

vehicle technology, high powered microwave

or laser transmission devices), which would

reduce the economic risks. Here, as in the

strictly research phase of an SPS program, it is

very important to be cognizant of other space

and energy programs that could benefit from

dollars spent on SPS research and vice versa.

Safety and Health Risks. –OTA pursued no

independent study of health and safety risks of

the five technologies. This assessment has

therefore relied on the work of Argonne National Laboratory that was funded by the SPS

office of DOE. ’9 The reader is referred to its

report for a comprehensive treatment of the

problem (see also app. D). The Argonne study

attempted to quantify risks in terms of the

number of fatalities that would occur per year

for a specified plant output (see fig. 29). Some

of the issues are unquantifiable, and for the

‘(’G R Woodcock, “Solar Power Satellites ~nd the Evolution

of Space Technology, ” presented at A I AA Meeting, May 1980

Figure 29.—Quantified Health Effects

77

10.0r

Operation and

maintenance, public

Operation and

maintenance, occupational

Construction, mfr.

LWR CG/CC LMFBR CTPV SPS MCFusion

& cc

SOURCE Program Assessment Report Statement of Findings, SPS Concept

and Evaluation Program, DOE/ER-0085, 1980.

SPS and fusion, most of the issues are in this

category. The difficulty of quantifying issues

for SPS and fusion is a function of the uncertainties about the final configuration these

technologies will take as well as the lack of experience with them upon which to base estimates of fatalities. This is an area that needs

considerable further study, not only for SPS

but in every other comparative study of energy

technologies. The major needs are to put all

the data on as common a basis as possible and

to quantify risks where they are currently unquantified (see ch. 8 for a summary of SPS

health and safety risks).

Environmental Risks. –As with health and

safety risks, OTA attempted no independent

analysis and has relied on the comparative

assessment study of Argonne National Laboratory. 20 Table 18 summarizes the most important environmental effects for each of the

technologies under study, plus coal. The nuclear technologies have been grouped together

because their effects are common to all the

nuclear technologies.

‘“L J H abegger, J R Gasper, and C D Brown, “Health an d

Saft’tV Pr~~llmlnary Comparative Assessment of the SPS an d

Other F nt’rgy Alternatlve~, ” DOE report No DOE/E R-0053, April

1 98()
Ch. 6—SPS in Context . 127

Table 18.—Major Environmental Risks

Coal Nuclear SPS

Air pollution Catastrophic events Atmospheric changes

Atmospheric changes Land use Bioeffects from microwaves,

(CO2

, particulate) Thermal discharge waste lasers, reflected light

Esthetic deterioration disposal Electromagnetic disturbance

Land use Land use

SOURCE: Office of Technology Assessment

Other factors. – How well would SPS compete with other baseload electric technologies? This question can ultimately be

answered only in the context of overall demand for electricity, considerations that are

taken up at the end of this chapter. However, if

demand for electricity is such that SPS may be

needed to supply a portion of that demand,

then the competitive position of SPS vis-a-vis

the other technologies will depend primarily

on its being cost competitive, and presenting

comparable health or environmental hazards

to the other technologies. Other utility concerns such as its reliability and rated capacity

factor have direct and obvious economic impacts that are subsumed in the condition of its

being cost competitive. It is too early to tell

whether SPS can compete effectively. What is

clear, however, is that factors beyond the

scope of control of an SPS program may determine more effectively whether SPS is competitive than the important concerns over

costs or health and environmental effects. The

effects of reduced coal useage are examined

below. However, before the United States

needs to decide whether it is prudent to continue or expand coal burning (c 2000), it must

make a decision about the use of breeder reactors (c 1990). If we institute a strong breeder

program, then SPS is less likely to be needed

than otherwise, simply because breeders are

apparently cheaper to build and operate than

the SPS. They have the further competitive advantage that they strongly resemble LWRS,

both in operating characteristics and in health,

safety and environmental impacts.21 Thus, utilities are more Iikely to purchase breeders than

to take on a brand new technology whose ma-

“E. P Levine, et al , “Comparative Assessment of Environmental Welfare Effects of the Satellite Power Sytem and Other

Energy Alternatives, ” DOE report No DOE/E R-0055, April 1980

jor resemblance to terrestrial technologies is

the fact that it produces electricity. However,

perhaps more important is the fact that

breeders could play a significant role in supplying electricity 10 to 20 years before the SPS,

thus giving them an automatic competitive advantage.

Although the fusion program has not yet

proven that it is possible to generate more

energy than is fed to the fusion process, the fusion community is confident that the production of electricity from fusion is a matter of

continued R&D. The costs are more uncertain

than for SPS. However, fusion has a strong

followlng inside and outside the fusion community. Furthermore, the utilities are already

actively pursuing fusion studies. Therefore, if

fusion’s costs turn out to be competitive with

SPS, it too may be chosen over SPS because it

has a strong following and because beyond the

first wall, it is similar to other nuclear options

in the way in which it generates electricity.

However, it may not be capable of making a

significant impact on the supply of electricity

untiI welI after SPS, i.e., not until 2030 or later.

Because several proposed versions of the

SPS are designed to use PV cells, a terrestrial

PV system constitutes an obvious comparison

to the SPS. The satellite or SOLARES ground

site would receive continuous sunlight. A terrestrial system, however, receives constantly

varying sunlight. Table 19 compares the peak

and total annual insolation in space, at a

SOLARES ground station and in Boston and

Phoenix for an optimally tilted flat-plate, nontracking solar collector. Therefore, a terrestrial

PV in Phoenix the size of a reference system

rectenna would, in theory, be capable of producing as much electricity on a yearly basis as

the reference satellite. However, the output of
128 Ž Solar Power Satellites

Table 19.—Terrestrial and Space Insolation Compared

Average annual Area needed to produce 1,000 MW

Peak insolation (per insolation (per (per continuous output on Earth

square meter) square meter) (17-percent efficiency cells)

Space. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 kW 11,800 kWh 10 km2

SOLARES GND Station (29° latitude). . . . . . . . . 1.3 kW 9,734 kWh 6 km2

Boston. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.8 kW 1,430 kWh 44 km2

Phoenix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 kW 2,410 kWh 26 km2

Equivalent rectenna area for reference

system—35° latitude. . . . . . . . . . . . . . . . . . . . . — — 28 km2

—.

SOURCE: Office of Technology Assessment,

such a central terrestrial system would be subject to short-term and seasonal variations in

output due to fluctuations in insolation

brought out by cloud cover. This effect is illustrated in table 20 for the Boston and

Phoenix areas. The daily insolation for the

month of December is 28-percent less than for

the average month, resulting in 28- percent less

PV output for the same sized array. Phoenix,

by contrast, experiences average insolation

values only 14 percent lower than the average

in July, its month of lowest insolation.

Decentralized Electrical Generation

Although technologies that are capable of

producing electricity in a dispersed mode may

not be direct competitors of centralized

technologies, they will compete for a percentage share of overall electricity supply in this

country and the world. In 1977, the residential

sector of the electrical market constituted 36

percent of this Nation’s demand for electricity.

If a significant portion of this demand as well

as part of the demand for commercial and industrial consumption can be met by dispersed

technologies such as solar PV, wind, and

biomass at costs that are competitive with centralized electricity, then the demand for centrally produced electricity will drop. Low demand for centrally produced electricity will in

turn reduce the need for new, large-scale

generating technologies and place them in a

poor competitive position with respect to

proven technologies. Thus, it is of considerable

interest to investigate the role that dispersed

electrical technologies may play in the Nation’s energy future.

Dispersed modes of generating electricity

are first and foremost attractive in remote

regions where the electricity grid has not yet

penetrated. It is in these areas where windmills

and PV, with storage, are now being installed

even though their cost is high relative to the

price of grid-supplied electricity.

As experience with these technologies

grows, and their price decreases due to deeper

market penetration and increased commensurate production, they are likely to penetrate

areas that are now served by the utilities. Such

a shift will be aided by the Public Utilities

Regulatory Policies Act of 1978 (PURPA) that

requires utilities to purchase electricity from

renewable-based powerplants at their avoided

cost of power. To date, State regulatory commissions have established prices that are equal

to, or higher than, the retail price of electricity.

If this practice should continue into the mid1980’s, onsite electrical generating systems will

not only provide energy for their owner’s use,

but will become income generators as well.

This shift will be further aided by the attractiveness of modular units that allow a homeowner or community to become relatively selfreliant and independent of large-scale generating systems over which they have little control.

Additionally, onsite systems can be erected

rapidly and incrementally, allowing a close

match of supply to local demand. Under such

conditions, it can be expected that there would

be a rapid increase in demand for small-scale

systems.

The role of dispersed electrical generating

technology in the Nation’s electrical supply is
Ch. 6—SPS in Context ● 129

Table 20.—Terrestrial Insolation at Different Latitudes and Climates

Boston: Latitude 42.2

Jan. Feb. Mar. Apr. May June - Jul y Aug. Sept. Oct. Nov. Dec.

kWh/m23.4 3.7 4.1 4.0 4.4 4.3 - 4.6 4.4 4.4 4.1 3.0 2.8

kWh/m2

/month 104 104 126 119 135 129 142 137 131 126 90 85

Total insolation per year 1,430 kWh/m2

Average daily insolation: 3.9 kWh/m2

Phoenix: Latitude 33.3

Jan. Feb. Mar. Apr. May June - Jul y Aug. Sept. Oct. Nov. Dec.

kWh/m2/day 6.0 7.0 7.4 7.5 6.6 6.2 5.7 6.2 7.0 7.3 6.7 6.0

kWh/m2

/month 184 195 228 225 204 186 178 185 218 227 200 185

—

Total insolation per year 2,414 kWh/m2

Average daily insolation: 6.6 kWh/m2

SOURCE: Solar Photovoltaics: Applications Seminar, Planning Research Co

the subject of another OTA study that will

discuss the full array of dispersed electrical

technologies: wind, PV, and biomass. How

ever, because much of the technology for constructing space-rated solar cells will be applicable to terrestrial applications and vice

versa, this report explores the possible role of

dispersed PV systems in filling part of this

country’s electrical needs in the time frame of

the SPS.

Dispersed Photovoltaic Systems. —The most

important single characteristic that makes PV

of considerable interest for dispersed uses is

their relative insensitivity to economies of

scale for generating electricity because PV are

modular, allowing considerable flexibility in

their location. Economies of scale are very important in their production, however. The present high cost of PV (about $7/peak watt) is

largely due to a very small production capacity. About 4.5 MW (peak) of terrestrial capacity

were produced globally in 1979, by only a

dozen manufacturers. Demand exceeds supply, however, even at $7/peak watt and thus

the market will surely expand, especially

as new manufacturing techniques allowing

cheaper PV are developed. All indications are

that continued reduction in price in line with

DOE cost goals will accelerate the demand for

PV cells for all applications and in particular

for dispersed systems that are either connected to the utility grid or stand alone.

Meeting this cost goal is important for the SPS,

which in the reference design, is highly sensitive to PV array costs (34 percent of satellite

costs).

The total penetration of PV and other decentralized energy technologies into the residential, commercial, and industrial sectors of the

energy economy will depend on a number of

interrelated factors in addition to cost. The

following summary indicates the most important ones.

● Average Available Sunlight. –The best

areas for dispersed PV are the same ones

where centralized applications are most

plausible, i.e., in desert climates such as

the Southwestern United States. However,

the variation of regional average insolation across the continental United States

is less than a factor of two. Changes from

year to year are considerably less. Both effects are smaller than variations in energy

consumption and price patterns. Thus,

regional or annual insolation variations

are not likely to be a strong determinant

of PV penetration. This will be even more

true in areas where biomass and wind

systems can work in complementary

fashion with PVs.
130 ● Solar Power Satellites

●

●

●

●

Storage. – Advances in storage technology

could have a significant effect on the market penetration of PV systems, particularly for remote and stand-alone applications. It is generally agreed, however, that

low-priced storage, if it is ever developed,

is a decade or two away.

The Use of Centralized Photovoltaic Systems. — Using PV for peaking or intermediate generating capacity will enhance

the development of low-priced PV cells

and the auxillary equipment (mounting

panels, inverters, etc.) and speed the introduction of dispersed PV systems to

marginal areas (i. e., areas where the centrally generated electricity is cheaper than

onsite generation).

Conservation. –Conservation has already

resulted in important reductions in percapita energy use. In the Washington,

D. C., area for example, use of electricity is

increasing by only 1.4 percent a year,22 a

sharp contrast to the 7 percent yearly increase in consumption that was common

in the mid-1 970’s. Continued price increases for energy will increase the desire

to conserve energy and make the total

needs of a residence, for instance, much

less. The Virginia Electric Power Co., for

example, reports that in its service area

all-electric homes, used about 24 MWhr/yr

in the mid-1 970’s, but consumed only 19

MWhr for 1979,23 a 20-percent drop. Decreases in total consumption make it

more likely that PV systems can be sized

to meet the needs of the residential sector<

Other Dispersed Sources of Electrical

Power. –The acceptance of wind and biomass for dispersed electrical generation,

or as substitutes for electricity, may enhance the desire for photovoltaics as individuals and the utilities become accustomed to working with dispersed sources.

However, if other sources failed to make a

significant impact because they were expensive or because they didn’t work well,

?>wfa5h;ngton Post, Mar 25, 1981, P D-9

“Washington Post, June 23,1980, p B-1

●

●

●

they could have the opposite effect on the

use of PVs.

Cost of Photovoltaics. – Single-crystal

silicon cells are highly energy intensive.

Thus, the energy cost of producing them is

high, and if energy prices increase, the

cost of the cells will be higher than the

DOE goals. New production techniques

for amorphous silicon or other materials,

however, may lead to less energy intensive cells, and the problem could be

avoided.

Reliability y. –One of the major reasons for

preferring centralized power generation is

the high reliability of electrical service.

Dispersed systems must be reliable in

order to capture a significant portion of

the electricity market. The PV themselves

are extremely reliable. However, the associated equipment is subject to a higher

failure rate. Market penetration will

therefore depend on a highly reliable

product and effective, timely service to

repair failures.

Institutional Effects. – PURPA regulations

wiII enhance the use of dispersed-systems.

If these regulations are retained and if

they are carried out effectively on the

local level, then they will be effective in

speeding the introduction of dispersed

electrical capacity. However, a number of

negative effects (e. g., low reliability, high

costs, etc.), could cause such regulations

to be repealed if they are found to work

inefficientIy.

In summary, it can be said that the future of

dispersed electric systems, and PV in particular, is subject to considerable uncertainty.

If cost goals are met, and the effect of the

other factors is positive overall, then dispersed

electrical systems could make a significant

contribution especially in a future in which the

demand for electricity is relatively low. As

table 21 illustrates, the cost per kilowatt-hour

for grid-connected PV systems, though subject

to considerable uncertainty, is competitive

with baseload systems. By combining several

different kinds of dispersed sources of electricity (e.g., wind, PV, and biomass), the prospects for dispersed PV sales becomes even
Ch. 6—SPS in Context ● 1 3 1

Table 21.–Costs of Onsite Photovoltaics (1980¢/kWh)

Househol d Industry

Without storage With storage* Without storage With storage*

Boston Phoenix Boston Phoenix Boston Phoenix Boston Phoenix

Roof replacement. . . . . . . . . . . . . . 3.0¢ 1.8¢ 9.0¢ 7.O¢ — —

Flat on roof . . . . . . . . . . . . . . . . . . .

— —

3.9¢ 2.3¢ 9.9¢ 7.6¢ — — — —

Columns on roof or ground . . . . . . 8.3¢ 4.9¢ 14.7¢ 10.4¢ 8.O¢ 4.7¢ 18.9¢ 12.9¢

NOTE: These costs were developed assuming photovoltaic arrays costing $35/m2 and 17-percent efficiency in space (18 percent on ground). Further details of the

assumed systems can be found in app. B.

● Assumed a 80-percent capacity backup generator,

SOURCE: Office of Technology Assessment.

stronger than when used alone. As in the case

of the baseload technologies, these figures

must be seen as indicative of the range of costs

that may be attained and should not be used as

a basis for comparison at this time. Considerable development wilI be needed to determine whether the various cost goals can be

met.

Implications

Introduction

The discussions just completed illustrate

that the future of the SPS, assuming it can be

developed technically, depends on a variety of

factors. These include the future demand for

electricity and how SPS compares with other

supply technologies. There are two questions

to be answered: 1) is the SPS necessary at all?

2) if so, when do we need it? The section on demand showed that future electricity needs are

highly uncertain and are dependent on technological developments that can profoundly influence the costs of various end use technologies. The section on supply contained discussion of several technologies that would compete, partially or completely, with the SPS to

supply electricity for the long term. The section gave criteria for choosing between these

technologies and the range of uncertainty

about their potential success. From the discussion it is clear that a variety of factors beyond

purely technical success will determine which

supply technology(ies) wiII emerge.

To see this more clearly, OTA chose three

hypothetical U.S. energy futures in order to examine possible future supply mixes. They were

chosen to span a wide range of possible electricity demand scenarios for 2030. The lowest

assumes no change from our present end-use

demand for electricity, the highest uses the

1979 Energy Information Administration (E IA)

high projection for 2020 extrapolated to 2030,

and the mid-level is halfway between. These

futures were chosen as an exercise to illustrate

the way various technologies might be used

and the constraints placed on this selection.

OTA does not treat these demand levels as

forecasts of what will occur, but as a plausible

range of future end-use demand.

The extremes of the three scenarios are

characterized by zero growth in electricity demand for the low scenario, and an average

growth of 2.8 percent per year for the high

scenario from 1980 to 2030. The growth in the

high scenario is not steady, however, but starts

at 4.1 percent in the 1980-95 time period, and

declines to 1.9 percent by the end of the scenario in 2030.

The low scenario represents a conservationoriented energy strategy, in which the increases in industrial output and residential and

commercial space are offset by improved efficiency of electricity use for industrial processes and drives, and residential and commercial heating, air conditioning, lighting, and appliances. The end-use electricity level in the

low scenario, taken from the CONAES scenario A, assumed electricity demand at a constant level of 7.4 Quads for 1980 to 2010, and

extrapolated the same constant level to 2030.

That level is very close to the actual end-use

electrical consumption in 1979 which was 7.6

Quads. The total primary energy consumption
132 ● Solar Power Satellites

in the CONAES scenario A is 74 Quads, compared to actual use in 1979 of 78.9 Quads.24

The high scenario represents a major expansion of the use of electricity in all sectors. The

scenario is taken from the E 1A Series C projection from the Long-Term Energy Analysis Program. The total primary energy use in this

scenario is 169 Quads. The scenario projects a

major shift in residential fuel use, with electricity supplying 60 percent of all residential

needs and 55 percent of residential heating.

(Water and space heating alone are projected

at 8 Quads end-use electricity in 2020.) Electricity is expected to provide 70 percent of the

commercial energy demand in 2020. In this

project ion, EIA forecasts that the industrial

sector wilI grow faster than any other sector,

and that industrial use of electricity will triple

or quadruple by 2020. Total energy use in the

industrial sector in the scenario is 63 Quads in

2020. Electricity’s share of the industrial

energy sector rises from 11 to 20 percent. The

dominant supply technologies in the scenario

are coal and nuclear, with coal providing 60

percent, nuclear 33 percent, and hydro and

other renewable the remainder. The E 1A scenario was extrapolated to 2030, using the same

electric growth rate as assumed in 2010 to

2020, namely 1.9 percent. According to the extrapolation of this scenario, the total energy

use in 2030 is 196 quads and the total electricity use is 30.2 Quads (end use).

The middle scenario is chosen to be the midpoint between the high and low scenarios at

each of the decades projected. The end-use

figures for each of these three scenarios are

given in table 22.

OTA does not suggest these demand levels

as forecasts of what will occur. These futures

24[ner~y jn Trans;tjon, OP c I t

Table 22.—Range of Energy Demand in 2030

End-use electrical Primary total

Scenario (Quads) energy (Quads)

High . . . . . . . . . . . . . . 30.2 196

Mid . . . . . . . . . . . . . . . 18.8 135

Low . . . . . . . . . . . . . . . 7.4 74

SOURCE: Office of Technology Assessment.

were chosen to illustrate the way various technologies might be used and the constraints

that might be placed on their selection.

To characterize the mix of supply technologies possible under these scenarios, a number

of questions was addressed. Among these

questions were the numbers and kinds of technologies that would contribute to the supply

mix under the various scenarios, the maximum

reasonable SPS contribution under each scenario, the most likely technologies to replace

SPS were it not deployed, and the relative implementation rates of the various technologies

under different demand conditions. The exercise carried the simplifying assumption that

one technology could be substituted for

another These questions cannot be answered

precisely, but their discussion leads to interesting insights into the potential role of SPS.

Low-Demand Future

For this case, end-use energy demand for

electricity is selected to be 7.5 Quads (today’s

level). A zero electric growth future is likely to

be the result of substantial conservation –

probably resulting from high energy prices —

and the failure to develop end-use technologies that use electricity at a lower net cost

than technologies using liquid or gaseous fuels

and direct solar. The principal feature of this

future is that electricity demand can be satisfied without SPS, fusion or breeder reactors.

The supply potential of coal, hydro, ground

based solar (including wind) and conventional

nuclear would be more than sufficient to meet

demand Even if coal were to be phased out

due to negative findings about the CO, buildup, its share could probably be absorbed by

other sources. Zero growth in electricity demand gives the nation considerable time for

developing new technologies.

In this situation utilities would only need to

replace retiring plants. Therefore they would

have considerable latitude in choosing technologies. Further, a zero growth rate would not

favor large plants because they would add too

much capacity at one time. Therefore, smallscale, dispersed technologies may play a major

role in this future. If any of the new tech-
Ch. 6—SPS in Context ● 1 3 3

nologies under discussion are introduced they

will have to appear in relatively small increments in order to maintain system reliability. For example, one could expect SPS to provide no more than 1 to 2 Quads at any given

time to the 7 to 8 Quad total. This would act

strongly against an SPS the size of the reference system since it would only require 7 to

15 units of 5,000 MW at a 90-percent capacity

factor to supply this much energy. Therefore

deployment of any SPS would depend on an international demand for electricity and/or the

development of much smaller units than the

reference system (perhaps on the order of 500

MW). A similar argument could be made about

fusion and breeder reactors, although current

development plans show the size of eventual

commercial plants to be 1,000 MW or less.

In summary, a scenario that shows little or

no increase in electricity demand for the next

several decades does not appear to be attractive for accelerated SPS development, particularly of the reference system. At the same time,

development of other central, baseload supply

options ultimately competing with SPS could

also be slowed. The choice among these, if

needed at all, would primarily depend on

which ones could most economically be developed in smaller sizes.

Middle Demand Future

In this case net electricity demand reaches

about 20 Quads in 2030 representing about a 2-

percent growth rate per year that is close to

that which the Nation is now experiencing.

Although this is about 2.5 times current electric energy demand, it too could be met without using the SPS, fusion or the breeder reactor. For example if two-thirds of the 20 Quads

were produced by coal, it would require a tripling of present yearly production, which is

within the Nation’s capability. Current estimates of domestic uranium reserves are sufficient to supply another 6 Quads in 2030. In addition, a major contribution from terrestrial

solar (wind, onsite PV) can be expected to help

meet increased intermediate and peak load

demands that coincide with solar peaks (space

heating and cooling). If growth continues past

2030, this mix may be insufficient. Yearly coal

production could probably not be expanded

too much beyond this (tripled) level without

straining other sectors of the economy, and by

2030 the Nation may be near its uranium resource limits. Therefore, to ensure supply

beyond 2030 and to replace retiring nuclear

plants, some level of new, centralized technologies would probably be needed.

If coal and conventional nuclear remain acceptable, it is not likely that all three of the

major centralized technologies under development would be needed. The contribution they

could make by 2030 would be small because of

the time needed to bring them on line and the

fact that they would be starting from a zero

base sometime near 2010. A 10-percent contribution to 20 Quads would require anywhere

from 60,000 to 100,000 GW, depending on

capacity factor. Unlike the low demand future,

this would allow SPS units of up to 5,000-MW

size to be added if continued growth past 2030

is expected. A 2 percent per year growth rate

means about 0.4 Quad/yr added at that time.

This could be supplied by three SPS plants per

year at the reference design size, in addition to

baseload units to replace retired pIants. This is

stiII a small enough increment that smaller SPS

pIants appear to have an advantage. In addition, this demand increment is still not too

large to rule out its being met by onsite solar,

wind, and centralized solar. All have much

lower energy densities than fusion or breeders,

however, and eventually their contribution will

be limited by available area. About 25 m2 are

required to supply a continuous kilowatt of

solar electricity assuming PV conversion efficiencies of 20 percent. The entire 0.4 Quad

could be supplied by about 125 mi2

, not an

unreasonable area.

If coal is not acceptable because of C02

then there will have to be a substantially larger

contribution by the newer technologies. In this

case it is plausible that all three, plus substantial ground based solar, would be needed.

Such a replacement could be achieved with

these new technologies but it would be a

sizable effort. If coal supplied just half of the

electricity in the case discussed above, about
134 ● Solar Power Satellites

10 Quads of new electric energy would have to

be found, requiring 300 to 500 GW. If new

plants were on the order of 1,000 MW in size, a

construction rate of 15 to 25 per year would be

needed assuming they were first available in

2010. Under this future of constrained coal,

then, there would appear to be sufficient demand for al I technologies to be introduced at a

rate that would pay for their development in a

reasonable period. Also, it is not Iikely that any

one technology wouId be relied upon to supply

the entire 10 Quads at the end of this 20 year

phasing-in period. An even three-way split, for

example, would mean that SPS would supply

about 100 to 150 GW by 2030.

High-Demand Scenario

This future assumes a final demand for electricity of 30 Quads (about four times the current level), meaning a growth rate of about 2.8

percent per year. At that rate, about 0.8

Quad/yr would be added in 2030. If one

assumes an increase in net conversion efficiency from today’s 29 to about 35 percent and

an increase in capacity factor from 42 to 55

percent, then this total demand could be met

by an installed generating capacity about

three times today’s figure. Efficiency and

capacity factor will almost certainly have to

increase if a 30-Quad demand is to be met.

Total system capacity would be in the range of

1,200 to 2,400 GW (1,800 GW at 55-percent

capacity factor).

To be able to supply this much electric

energy, all technologies would probably be

needed. Further, larger plants are likely since a

demand increment of 0.8 Quad/yr would require about 40,000 to 50,000 MW of new capacity per year. Therefore, addition of plants

ranging from 1,000 to 5,000 MW would not

cause any significant short- or long-run overcapacity problems. Because of the large

amount of capacity needed, conventional nuclear and coal will probably be able to supply

only about two-thirds of the total (i. e., about

1,200 GW) before they reach the limits discussed above. Thus, about 600 GW must be

supplied by hydro, ground based solar, geothermal, and some combination of SPS, fusion

and breeders. Breeders are likely to supply the

bulk of this by 2030, provided they are acceptable, since they are the closest to commercial

readiness. Even so, as much as 200 GW of SPS

could be needed by 2030. The SPS development would have to be accelerated if it is to

meet a goal like this. The same holds true for

fusion, which could also be required to supply

around 100 GW by 2030.

The mix of technologies will be determined

substantially by constraints such as environmental concerns, capital, land and water availability, materials Iimitations and labor requirements. For example, limited water would favor

SPS and ground-based solar PV. Limited capital, however, would favor the least capitalintensive technologies such as coal and act

against the SPS. In any event, these constraints

will be very important at this demand level

because of the large number of powerplants

needed

If coal must be phased down or eliminated

then even larger demands will be put on the

new technologies. For example, if coal and

conventional nuclear couId only meet onethird of the demand, an additional 600 GW of

capacity would be needed. In this case it is

probable that an all-out breeder program

would be needed. This should not affect the

SPS– in fact, more satellites may be needed–

but it could actually reduce fusion’s contribution since it is a competing nuclear technology. The terrestrial, onsite solar contribution

will have to be large in either case but is very

unlikely to be able to supply even one-half of

the 30 Quads. Even 20 percent of the demand

would require a very large deployment of PV

systems — nearly 400 GW of dispersed generating capacity.

Conclusion

The size of future electric demand will be

the major determinant in the amount of SPS

capacity installed, assuming successful development and competitive price. Table 23

shows estimates of the upper range of SPS

capacity available for each future for the case

of fulI coal development and coal phaseout.
Ch. 6—SPS in Context Ž 135

Table 23.–Upper Range of SPS Use (in GW)

Future (Quads) With coal Without coal

7.5 0 0-30

20.0 0-60 100-200

30.0 100-200 100-200

SOURCE: Office of Technology Assessment

In addition to determining the upper range

of the contribution of SPS the demand level

and rate of growth will also determine the

preferred unit size. For the low scenario,

smaller plants would be preferred since overcapacity problems caused by adding too much

at once would probably more than offset gains

made by any economy of scale. For the upper

future, however, for even the largest SPS proposed plant size, it is unlikely that too much

can be added at once for any reasonable construction schedule. The mid scenario, however,

gives somewhat ambiguous results, although

the smaller size SPS systems appear generally

to be more desirable.

For the first two scenarios it is unlikely that

alI three major, centralized supply technologies will be needed simultaneously, even if

coal cannot be used. Onsite, dispersed solar

will be able to make up a larger percentage of

the needed capacity and could eliminate the

need for any new centralized technology in the

low demand case. In all cases, coal can be the

dominant source and continue in that role for

several years past 2030. Finally, as the demand

for electricity increases,

pacity mix will become

pendent on physical and

cause of the sheer size

quirements.

THE EFFECTS OF SPS ON CIVILIAN

SPACE POLICY AND PROGRAMS

The effects of SPS development on the U.S.

civilian space program would be great, though

their precise type and magnitude would depend on the kind of SPS built, the overall

speed of the development program and the

status of space capabiIities at the time. An SPS

program would stimulate more rapid development of space transportation, large-structure

assembly and manned-mission capabilities,

and automated operations. SPS development

would also have a bearing on national space

policy and institutional structures, both Government and private sector. The following

discussion will examine four areas: 1) space

policy, 2) current and future space projects, 3)

institutional structures, and 4) indirect effects

and “spin offs.”

Space Policy

The Nation’s space policy is a reflection of

broad national goals. The principles guiding

the U.S. civilian program were first enunciated

in the 1958 National Aeronautics and Space

Act, and have been periodically reaffirmed

with minor modification

decisions about

more and more

labor constraints

of the capacity

cadebereand changes of emphasis. The 1958 Act states that “activities in

space should be devoted to peaceful purposes

for the benefit of all mankind,” to promote the

“general welfare and security of the United

States “ The Act specifies that civilian activities shall be directed by NASA, and military/defense operations by the Department of

Defense. The specific aims of the space program include: expansion of knowledge, improvement of space transportation, “the preservation of the role of the United States as a

leader in aeronautical and space sciences,”

and cooperation with other nations. NASA was

established to “plan, direct and conduct

aeronautical and space activities. ”25

These general goals and this framework

have been reaffirmed subsequently, most

recently in the “Directive on National Space

Policy” and the “White House Fact Sheet on

—

‘

5

’’Natlonal Aeronautics and Space Act of 1958, as Amended, ”

in Space Law, Selected Basic flocuments, Senate Committee on

Commer[ e, Science, and Transportation; U.S. Government Printing Of flee, 1978; pp 499-503
136 ● Solar Power Satellites

U.S. Civil Space Policy,” both issued in 1978. In

these documents the Carter administration

committed the United States to increase scientific knowledge, develop useful commercial

and Government applications of space technology, and “maintain United States leadership in space technology. ” Establishing and

maintaining satisfactory relations between the

civil and military programs was recognized as

a priority issue, and the National Security

Council was charged with providing coordination for all Federal agencies involved in space.

Cooperation with other nations, including joint

programs and the development of a stable

legal regime allowing all nations to use outerspace for peaceful purposes, were emphasized

as important goals. The investment and direct

participation of the private sector in space activities was addressed in the context of remotesensing systems. NASA’s responsibilities for

the operation, as opposed to research, development, and testing, of applications systems have yet to be clarified.26

The U.S. civil space program can thus be

said to have an ongoing set of policy goals:

●

●

●

●

●

●

scientific — increasing knowledge,

political — maintaining U.S. preeminence,

and

economic–developing useful commercial applications.

It also has a continuing policy framework:

separation of civil and military programs

(with various mechanisms for coordinating different efforts),

cooperation with foreign countries and

agencies, and

separation of NASA R&D and prototype

development programs from commercial

applications (an unclear relationship).

Would an SPS program alter the basic thrust

of U.S. policy? I n terms of goals, an SPS program would be primarily an applications effort

for commercial purposes, and hence would

26’’ Description of a Presidential Directive on National Space

Policy, j une 20, 1978, ” and “White House Fact Sheet, U.S. Civil

Space Policy, Oct 11, 1978,” in Space law, pp 558-564.

further the economic goals that have been emphasized in recent policy proclamations.

The political end of U.S. preeminence in

space, though no longer stressed as strongly as

during the Apollo program, would also be

served by commitment to an SPS. (This

assumes that the project would be successful;

failure of such a high-visibility effort could be

extremely damaging to U.S. prestige. International cooperation might tend to mitigate this

danger. )

The SPS program would not be focused on

increasing basic scientific knowledge, but

much of the research and experimentation required would provide some scientific gains; in

addition, the infrastructure for SPS (e. g., platforms, transportation vehicles) could be used

for a multitude of scientific projects in space.

There is some danger, though, that focusing

the national space program on such a major

applications project as SPS would divert resources and attention, at least temporarily,

from scientific missions.

The effects of SPS on the U.S. policy framework will depend on how it is financed and

managed. Civil-military relations could be

altered. Although the SPS is not technically

suited to be used as a weapons system, much

of SPS technology and infrastructure, especialIy the transportation vehicles, would have

military uses (see ch. 4). Furthermore, it is

unlikely that a project with the scope and impact of SPS could be approved by Congress

without at least the tacit consent of the Department of Defense (DOD). In the foreseeable

future, DOD requirements for aerospace expertise and facilities will be great, and SPS may

be seen as a competitor for scarce resources

unless direct defense benefits can be realized.

Although an SPS program would not be run by

the military, it might be necessary for the civil

and miIitary sectors to be more closely coordinated than has previously been the case.

Foreign cooperation and joint ventures

might be encouraged not only by the desire to

improve international relations but by more

direct economic considerations. (see ch. 7).

These considerations would be strong enough
Ch. 6—SPS in Context • 137

to provide for a greater degree of shared

responsibility than in any equivalent U.S. program to date, unless U.S. military involvement

proves an insuperable obstacle. International

participation might be such that the project

could no longer be run as a U.S. venture with

limited foreign cooperation, but would become a truly multinational effort with no

dominant U.S. role.

The relation between public and private

participants would be a major issue in any SPS

program. Policy in this area has not been clearIy established, though there is precedent for

detaching applications projects, such as satellite communications and Landsat, from NASA

after development is completed. NASA has

conducted all U.S. civilian launches on a

reimbursable basis; it is unclear what would

happen if private firms wished to build and/or

launch their own vehicles, as has been suggested for the shuttle. If, as is presently the

case, a Federal SPS program were managed by

DOE or some other agency besides NASA,

NASA might be responsible for only a limited

part of SPS development and NASA restrictions and policies might not apply.

Current and Projected Space Projects

SPS would be strongly affected by current

space programs and capabilities, and in turn

might also determine what many of those programs would be. However, since an SPS development decision is unlikely to be made before

1990, and may not be possible until 2000, (see

ch. 4), SPS will not shape NASA projects conducted during the next decade (though it may

affect long-range planning).

Historically, NASA has devoted the major

portion of its resources to a single major project, first the Apollo lunar-landing program,

and then the Space Shuttle. However, there are

currently no plans for a similar “centerpiece”

project to follow the Shuttle; the White House

Fact Sheet asserted explicitly that: “it is

neither feasible nor necessary at this time to

commit the United States to a high-challenge

space engineering initiative comparable to

Apollo.” Instead, present plans call for a

number of smaller scale operations and scientific missions centered around use of the Shuttle and other components of the Space Transportation System (STS). The lack of a single,

clear, overriding project goal for the civilian

space program has been criticized for squandering NASA and contractor capabilities, and

leaving the United States without a visionary

and profitable use for the new transportation

capabilities under development. This problem

will undoubtedly be addressed during the

1980’s, but jurisdictional and philosophical

differences, as well as budgetary constraints,

may make consensus difficuIt to achieve.

For the next 5 years, NASA plans to concentrate on a number of areas: those most directly

relevant to SPS include:

1. Transportation and Orbital Operations:

2

Transportation efforts will concentrate on

meeting shuttle schedules but also include other elements of STS: the inertial

upper stage, for placing payloads in geosynchronous orbit (CEO) (under development by the Air Force); Spacelab, for

manned and unmanned experimentation

(joint program with ESA); development of

orbital transfer vehicles such as an electric orbit transfer vehicle (EOTV); systems

to handle payloads outside of the Shuttle;

and free-flying platforms. Each of these

programs will be important for improving

our capability to move and work in space,

and hence directly relevant to SPS. The

key element is the Shuttle, which must

work and work well if these projects are to

proceed during the 1980’s. Delays in Shuttle operations, or in building additional orbiters, will not only retard these projects

but also might prevent SPS-specific research flights as envisioned in one of the

policy Options from taking place in the

late 1980’s (see ch. 4).

Immediate Applications: In this area,

space processing experiments to be conducted on Spacelab could be important in

determining the proper kinds of materials

for SPS construction, as well as prospects

for direct processing of raw materials in

orbit. Communications and remote-se ns83-316 0 - 81 - 10
138 ● Solar Power Satellites

ing development will involve work with

microwave transmission, lasers, and mirror systems, as well as detailed studies of

the upper atmosphere,27 which will b e

vital in determining the environmental effects of launch effIuents and energy transmission beams.

3. Solar Radiation:The Solar Maximum Mis4

sion (launched February 1980) and the upcoming International Solar Polar Mission,

scheduled for 1983, will study solar radiation and its effects on the near-Earth

space environment. Such information

could be important in designing SPS solar

cells and in adding to our knowledge of

the effects of radiation on SPS workers:

ionizing radiation in CEO is a potentially

serious obstacle to human effectiveness

and could be decisive in determining the

optimal “mix” between automated and

human-controlled operations.

Humans in Space: The studies of Shuttle

crew performance as well as specific

Spacelab experiments will provide a basis

for determining the long-term effects of

weightlessness and cramped quarters, and

for designing appropriate equipment to

improve manned performance. 28

The above projects are already underway

and are those for which funding or explicit

planning are in place. NASA has also outlined

other, longer term plans that would be important to SPS. NASA’s Office of Space Transportation Systems’ long-term goals are predicated

on the assumption that “the growth of U.S.

civilian space programs in the 1990’s will probably continue to be moderate and evolutionary, rather than rapid or ‘Apollo-like,’ “

and that “space projects will increasingly have

to demonstrate significant economic return or

perform essential services to obtain approval.”

The specific goals are: 1 ) routine operation of

the STS by the mid-1 980’s; 2) routine operation

of unmanned large low-Earth orbit (LEO) platforms by the mid-1980’s; 3) a permanent

manned facility in LEO for research, construcZ7N~t10nal Aeronautics and space Adm Inistration, ~AsA f’rogram P/an, F;sca/ Years 1987 Through 7985, 1980, p 1 0 7

*

a Ibid, pp 3-5

tion, and operations, by the end of the 1980’s;

and 4) a permanent facility in GEO, eventually

manned, by the late 1990’s. Meeting goals

wouId involve:

•

●

●

●

augmenting the Shuttle’s thrust, perhaps

via a Iiquid booster;

developing EOTVs, such as the low-thrust

ion-propelled Solar Electric Propulsion

System (SEPS) for service to geosynchronous orbit;

equipping the Shuttle and its modules

with a 25-kW add-on electrical power system; and

carrying-on a ground and space-based effort to fabricate and assemble precision

structures in orbit .29

All of these projects could have direct bearing on SPS and on any future decision to proceed with SPS development. Some of the

longer term aims, such as SEPs, might overlap

with an SPS development program, that would

provide a strong impetus for their completion.

NASA is not the only body with plans for

space. DOD goals, though largely classified,

include large platforms, orbital microwave

radars, and space-based lasers. DOD requirements couId drive NASA projects such as Shuttle thrust augmentation, or lead to separate

development of SPS-useful equipment.

Other long-range projects have been suggested by many individuals and organizations,

in and out of government. In the transportation area, these include very large fully

reuseable launchers; laser-propulsion; 30 Iightsails, to power low-acceleration transfer

vehicles or deep-space missions; 31 and massdrivers to lift material off the lunar surface, or

as a solar-powered propulsion system for

space vehicles.32 Other than the building of

full-scale permanent colonies, SPS is the

largest space project proposed to date, in

2’1 b[d Pp 190-20 5

‘

(lA Hertz berg, K Sun, W Jones, “Laser Aircraft, Astronautics

and Aeronautics, March 1979 p 41

“K Eric Drexler, “Spinoffs To and From SPS Technology: A

Preliminary Assessment,” OTA Working Paper, June 1980, p. 9

‘2(, O’NeIll, G Driggers, B. 0’Leary, “New Routes to Manufacturing In Space, ” Astronautics and Aeronautics, Octobe r

1980 Pp 465 1
Ch. 6—SPS in Context ● 139

terms of expense, returns, timeframe, and

amount of people and materials placed in orbit; if developed it would be a spur to all forms

of cheaper space transportation.

SPS’s effect on space projects would depend

to some extent on the type of SPS that would

be developed, the size of each unit, and the

size of the entire system (as well as the scope

and type of space program in place at the

time). A geosynchronous microwave SPS similar to the reference design would require extensive transfer vehicle capacity and hence

lead to accelerated development of EOTVs,

chemical-powered personnel vehicles, and

manned GEO construction stations. A laserSPS in LEO, on the other hand, would require

relatively little LEO to GEO transfer capacity.

A mirror-system might need even less upgraded Iift or construction capacity in order to

be fully deployed (see ch. 5).

A large SPS system consisting of many satellites would tend to have greater economies of

scale, leading to the development of more and

different sorts of vehicles, and greater massproduction and automation. In-orbit processing of lunar or asteroidal raw materials would

also be feasible only if a very large system

were built, to justify the front-end costs of

lunar mining and orbital processors.

Institutional Structures

Would an SPS program require a change in

current national institutions? The completed

SPS Concept Development and Evaluation

Program33 was a joint DOE/NASA effort, with

DOE providing most of the management and

NASA providing technical support. A decision

to have further SPS research, development,

and demonstration efforts managed by DOE

would likely prove awkward, since the bulk of

the up-front development costs would be for

space systems; hence DOE would have to pass

most of its SPS funding to NASA, or attempt to

develop its own contractor relations and inhouse space capability, which would be time-

“Satellite Power Systems Concept Development and Evaluation Program, “Program Assessment Report Statement of Findings,” November 1980, DO E/E R-0085

consuming and wasteful. SPS would require a

much clearer and stronger coordinating mechanism than currently exists for national space

programs, since not only NASA and DOE but a

number of other departments and agencies

would be involved. 34

Extensive NASA involvement in SPS would

require clarification of NASA’s appropriate

role in commercial applications ventures, and

perhaps modification of NASA’s charter. Both

underlying policy— i.e., to what extent NASA

shouId operate applications systems, such as

Landsat and communication satellites—and

specific procedures for turning over patents,

technology, and hardware to private industry

or other Government agencies, have been subject to continuing controversy. *

It is probable that a separate public or

quasi-governmental body would eventually be

set up, outside of NASA and DOE, to manage

an SPS program. Such a decision would be influenced by, among other things, the desired

mix of public and private funding, and the

degree of international involvement. Possible

forms such a body might take are discussed in

chapter 9, Financing Ownership and Control,

and in chapter 7.

Indirect Effects and “Spinoffs”

There would be three kinds of indirect effects of SPS development:

●

●

●

technology and hardware developed for

SPS that could have other uses (and that

otherwise would not be developed or

wouId be developed at a much slower

pace),

uses of the SPS itself other than providing

terrestrial baseload electric power (and

that would otherwise not be provided for),

and

economic/technological changes and basic shifts of national attitudes

SPS developed technologies and hardware:

Most, though not all, of these spinoffs would

relate to space capabilities. We have already

‘[J( )1 re[)ort on \ PS .1 nd Government dgenc Ief — In press

*See OTA assessment, Space Policy and Applications, i n

preparatio n
140 ● Solar Power Satellites

seen that NASA’s transportation plans include

many elements directly useful to SPS, which

SPS development would tend to accelerate or

modify. Although the reference system calls

for heavy-lift launch vehicles able to carry 400

tons to LEO, and a 5,000-ton payload EOTV,

the exact types of vehicles needed cannot yet

be specified. The proper mix between size,

numbers, and types of vehicles depends on

many unknown factors, including the type of

system, its location, and the number of satellites to be built.

The combination of improved and cheaper

transportation, robotics and teleoperation,

possible new construction materials (such as

graphite composites), and human expertise,

would make possible many commercial space

activities. Large communications platforms,

scientific and industrial research facilities,

processing plants for chemical and raw materials —these are a few possibilities. Past experience teaches that commercial exploitation

follows in the wake of the development of new

capabilities, and cannot be accurately foreseen. 35

Space industrialization could be greatly

enhanced by the use of extraterrestrial raw

materials. SPS could lead to lunar or asteroidal

mining by fostering the development of transport and robotics capacity, as well as by providing a major market for processed products

such as aluminum, steel, silicon, and oxygen.

The most detailed studies have examined mining the lunar surface, and launching raw

materials to orbiting processors via an electrically powered mass driver. Others have suggested mining or capturing a small asteroid,

preferably a carbonaceous-chondrite asteroid

rich in carbon and high-grade iron/nickel ore.36

Establishing such facilities, which might be

done in the later stages of SPS development,

could considerably reduce the costs of

transporting material to high orbits.

On the ground, SPS would require largescale automated production of solar cells;

‘

5 Woodcock, op cit , p 12

3’Drexler, op. cit , pp 10-11

some of this technology could also be used for

ground-based solar projects.

Space or ground-based industries using SPSdeveloped technology or hardware could, at

least temporarily, compete with SPS for scarce

resources. A mechanism for allocating priorities might have to be established to resolve

competing claims.

Alternative SPS uses; Depending on the electromagnetic environment (i.e., on the type of

system used and the amount and type of

shielding available), the SPS platform, whether

in (GEO or LEO, could be used as a station for a

variety of communication and remote-sensing

equipment. A GEO SPS wouId be especially

useful, due to the relatively small number of

positions available. Remotely operated optical

astronomy devices could be placed near or on

SPS as a way of escaping the interference

faced by Earth-based telescopes. Given a large

amount of space traffic associated with increasing industrial and military space flights,

the SPS station could become a focal point for

local storage, refueling, and rest and relaxation

for crews – a kind of spaceport. Living quarters

for maintenance crews and construction

workers could be expanded and upgraded into

occasional (and, initially, very high-cost)

tourist accommodations.

SPS electricity could be used in orbit, either

at the satellite itself or at remote sites

equipped with receiving antennas, to provide

power for industrial activities. Processing,

especially of extraterrestrial raw materials,

could require large amounts of electrical

power that might be more efficiently supplied

by a central SPS than by building specific electrical capacity.

Some SPS designs, especially the mirrorsystems, might produce enough power to be

used for local climactic modification. This

would require more precise understanding of

weather systems than is now available. Orbital

mirrors have also been suggested as a way of

providing nighttime illumination of cities

and/or of cropland to enhance growth. 37

‘“Woodcock, op cit
Ch. 6—SPS in Context . 141

Special mirror surfaces that reflect only

specific wavelengths would need to be developed for such purposes.

Generic economic and social effects: A successful SPS could be instrumental in provoking

an economic upsurge by stimulating new production in the aerospace and energy industries, and new industries altogether in space

fabrication, solar cells, antenna construction,

and so on. Specific technical advances necessary for SPS and Iikely to provide economic

spinoffs have been mentioned. The likelihood

of a revolutionary new product, comparable in

effect to the transistor or microchip, resulting

from SPS is unpredictable. Estimates of the aggregate economic and technical effects of

large research and engineering projects, such

as Apollo or nuclear reactors, vary enormously. Some credit a large portion of the U.S.

economic vitality and technical leadership in

the 1960’s, especially increases in research,

engineering, and project management skilIs, to

Federal investments in the Space program .38

‘

8 Drexler, op clt , pp 8-9

SPS might prove equally stimulating. Others

argue that these resources would have been

available anyway, and could have been used in

more efficient ways.

Arguments about long-term social vitality

aIso often revolve around the Apollo experience. The optimism and vision that

characterized the “Apollo decade” are con -

trasted with the pessimism, uncertainty, an d

sense of limits of the post-Apollo 1970’s. Skeptics, however, argue that Apollo represented a

misguided effort to escape from more pressing

social and political problems, and that the

space program lost public support when this

became apparent39 (see ch. 9). Whether the

United States will regain some of its former enthusiasm for large high-technology projects

wiII depend partly on the success of current efforts, such as the Space Shuttle, and on the

magnitude and type of benefits that such projects offer.

“Klaus Helss, “New Economic Structures for Space In the

I Ightlei, Astronautics ancf Aeronautics, January 1981, p 17
CHAPTER 7

THE INTERNATIONAL IMPLICATIONS

OF SOLAR POWER SATELLITES
Contents

Page Page

Introduction . . . . . . . . . . . . . . . . ......145

Degree and Kind of Global Interest in SPS .146

Economic Interest. . ................14 6

Noneconomic Interest . .............15 3

Legal Issues. . . . . . . . . . . . . . . . . . . . . . ...154

Status of the Geosynchronous Orbit. . . .155

Environmental Considerations . . . . . . . .156

Military and Arms Control Issues . .. ...156

Common Heritage and the Moon Treaty. 158

Advantages and Disadvantages of

Multinational SPS. . ..............15 9

Unilateral Interests. . . . . . . . . ........160

Multilateral Interests . . . . . . . ........162

Possible Models . ..................16 3

National Security implications of Solar

Power Satellites. . ................16 7

Vulnerability and Defensibility. . ......168

Current Military Programs in Space .. ..170

Use of SPS Launchers and Construction

Facilities . . . . . . . . . . . . . . . . . . . . . .171

Military Uses of SPS . ...............172

ownership and Control. . . . ..........173

Foreign Interest. . . . . . . . . . . . . . . . . . . . . .174

Europe . ........................17 4

Soviet Union . . . . . . . . . . . . . . . . . . . . . .174

Japan . . . . . . . . 175

Third World . . . . . . . . . . . . . . . . . . . . .175

Study Recommendations . ............17 5

LIST OF TABLES

Table No. Page

24. Primary Energy Demand. . ..............146

25. End-Use Electricity Demand . ...........147

26. Amount of Global Installed Capacity ., .. ..147

27. SPS Market in 2020/2025. . ..............151
Chapter 7

THE INTERNATIONAL IMPLICATIONS

OF SOLAR POWER SATELLITES

INTRODUCTION

The development of solar power satellites

(SPS) requires consideration from the perspective of its international implications. First, as a

space technology SPS would operate in a

global medium, outside of any national territory, which is subject to international law embodied in existing treaties and agreements.

Secondly, as a major energy project the SPS

would affect supply and demand for what is by

far the largest commodity traded on international markets, one that is of vital interest to

all countries. Thirdly, because of its tremendous cost and technical sophistication an SPS

system could have a strong effect on the economies of states involved in its construction.

And finally, development of an SPS and of the

launchers needed to build and maintain it may

give its builders significant military and/or

economic leverage over other states.

This chapter will look at the SPS primarily

from a political perspective, because in the

final analysis SPS development will depend on

national efforts, instigated by national leaders,

paid for– in large part– by public funds. The

United States is the only country in which

there is any likelihood that there would be

significant private-sector responsibility for SPS

decisions. The importance of national efforts

would be especially crucial in the near future

when SPS projects are in the R&D and prototype construction phases.

Actors. – If SPS is developed, Government

involvement would be guaranteed because

SPS would affect vital national interests in a

number of areas, e.g., external security, prestige and influence, and economic growth.

Energy policy in itself has become a central

component of national planning in most countries.

Nonstate actors would be involved as well.

On the international level these include global

organizations such as the United Nations and

its specialized agencies; multilateral groups

such as the Organization for Economic Cooperation and Development (OECD) and OPEC;

and regional groupings such as the Common

Market and the European Space Agency (ESA).

On the substate level there are numerous interests, including those of private companies,

public utilities, and governmental agencies,

that often conflict and that seek to influence

national decisions. Furthermore, the role of the

large multinational corporations in international relations is in some areas very great and

often independent of direct government control

However, for the SPS, national decisions and

interests are likely to predominate. Although

the rise of energy as a major global concern

has led to the formation of numerous international organizations (such as the International

Energy Agency) and to intense discussion of

the global dimensions of energy prices and

shortages, the overall impact has been to place

decisions about energy consumption and production more and more firmly in the hands of

national governments. In general, it seems that

the role of the state in furthering peace and

security, stability, prestige, and economic wellbeing has not been supplanted by other entities.

Forecasting. – Because SPS is a projec t

which, if pursued, will not reach fruition for at

least 20 years, assumptions must be made

about future political and economic developments. Since radical changes are by definition

unpredictable, these will be unavoidably conservative. In general, it is assumed that the

basic political and socioeconomic alinements

of today’s world are likely to continue. In the

past, fundamental realinements of the international political structure have often been the

145
146 ● Solar Power Satellites

result of major wars or of deep-seated altera- creasing skepticism in American and European

tions in political and social expectations, attitudes towards the space program and

neither of which can be confidently predicted. nuclear energy in the Iate 1960’s and early

Even relatively small shifts in public support 1970’s, for instance, has decisively affected

for various programs can have large effects; in- our current space and energy capabilities.

DEGREE AND KIND OF GLOBAL INTEREST IN SPS

National and regional interest in the SPS will

stem from an evaluation of the ways an SPS

system would affect all the components of national interest outlined above. The degree and

kind of interest shown will vary from nation to

nation. In deciding what institutional structure

to use for SPS development, it is crucial to

take these various foreign interests into account. In this case, interest can be divided —

somewhat arbitrarily— into economic and noneconomic components. The economic interest

in SPS would be focused on SPS’s ability to

provide electricity, and hence on the local demand for electricity over the time SPS becomes available. Noneconomic concerns

would include prestige and national security

interests.

Economic Interest

A recently completed study by the international Institute for Applied Systems Analysis

(IIASA), Energy in a Finite World,1 provides the

most up-to-date projections of long-range

future global energy demand. The IIASA study

uses a global model with several different

scenarios, broken down on a regional basis.

We will present the high and low estimates to

give the entire range of predictions; it should

be noted that the lower estimates are closer to

those of some recent U.S. studies, such as

Energy in Transition 1985-2010, by the National

Academy of Sciences. 2 (See app. C.) In general

the slowdown in gross national product (GNP)

growth over the past several years, and the

sharp rises in oil prices in 1979, have caused

‘Energy in a Finite Worid, A Global Systems Analysis, Energy

Systems Program Group, International Institute for Applied Systems Analysis (Cambridge, Mass.: Ballinger Publishing Co,, 1981).

‘Energy in Transition 1985-2070 (Washington, D. C.: National

Academy of Sciences, 1979).

recent energy forecasts to be much lower than

those of only a few years ago. Since OTA

believes that IIASA’s analysis may tend to

overestimate future energy demands (see app.

C), especially in the advanced industrialized

countries, the following figures should be used

with some caution.

The IIASA projections for primary energy

demand are based on an integrated model in

which supply and demand are matched on a

global basis (see table 24). (See app. C.)

Historically, the rate of growth in electrical

demand has been approximately twice as high

as that of total energy demand. IIASA predicts

that it will remain higher, but by a factor of 1.4

instead of 2.0.3

Currently, electricity accounts for a n

average of 11 percent of global end-use

energy, ranging from 6.5 percent in developing

countries to 12 percent in the OECD. By 2030,

IIASA expects this figure to rise to 17 percent

(in both high and low scenarios), with developing countries using 13 percent and OECD 21

percent, reflecting an annual increase in usage

of 2.6 percent (low) to 3.4 percent (high).4

‘Finite World, op. c it , p. 482.

‘Ibid

Table 24.—Primary Energy Demand (Quads)

—

1975 2000 2030

— Low High Low High

OECD. . . . . . . . . . . . . . . .146.8 200.3 224.5 266.3 393.4

SU/EE (Soviet Union,

E. Europe) . . . . . . . . . . 55.0 98.9 110.3 149.4 219.1

Developing . . . . . . . . . . . 37.7 107.0 148.9253.8 453.1

Global Total. . . . . . . . . . .239.5406 .2503.7669.5 1,065.6

S6URCE: Energy in a Finite World; conversion to Quads done by the Office of

Technology Assessment.
Ch. 7—The International Implications of Solar Power Satellites ● 147

Electricity use is affected by many factors,

including changes in end-uses, (such as heat

pumps or electric cars), saturation of demand,

and the cost and availability of fuel (see ch. 6).

Table 25 shows the IIASA figures for end-use

electricity demand.

Assuming 70-percent load factors and 15-

percent losses in transmission and distribution,

IIASA estimates for installed generating capacity in 2030 are shown in table 26.

Although the IIASA report is pessimistic

about the possibility of extensive use of alternative energy sources, such as fusion or

ground-based solar, by 2030, it points out that

a breakthrough in fusion or solar-cells would

change the supply and cost of electricity drastically. Cheap photovoltaics might encourage

a shift towards a “hydrogen economy, ’’with

electricity produced in high-insolation desert

areas being “stored” and transported as hydrogen. 5

Barring such developments, future baseload

electrical demand will be met overwhelmingly

by coal and nuclear sources (see app. C). IIASA

also predicts that coal will be used extensively

for producing liquid fuels, especially in coalrich regions such as North America and the

‘I bid., p. 163.

Table 25.–End-Use Electricity Demand (Qe)

1975 2030

— Low High

OECD . . . . . . . . . . . . . 12.5 35.3 50.2

SU/EE . . . . . . . . . . . . . 3.9 15.5 25.4

Developing. . . . . . . . . 1.8 23.3 41.3

Global Total . . . . . . . . 18.2 74.1 116.9

SOURCE: .Errergy in a Finite Wor/d, p. 659. These numbers should be taken as

approximations, since they are based on IIASA estimates of the per.

cent of end-use demand that will be met by electricity. For graphic

presentation, see Energy, p. 481.

Table 26.—Amount of Global

Installed Capacity (GWe)

1975 2000 2030

Low High Low High

1,600 3,550 4,390 6,320 9,845

SOURCE: Energy in a Finite World, p. 483.

Soviet Union — up to 55 percent of coal production in North America by 20306 (see app. C).

Regional Variations

In order to understand how different countries might view SPS, it is crucial to highlight

the major regional differences that will affect

demand for electricity. Foremost among them

is the question of regional or national selfsufficiency.

SELF-SUFFICIENT AREAS

In the 50-year time-frame considered, it appears possible for three major consuming

regions — North America, Soviet Union/Eastern

Europe, and China –to achieve energy selfsufficiency. This would require rapid development of indigenous sources of North American

oil shale, tar sands, and Western coal; for the

Soviet Union, untapped oil, gas and coal reserves in Central and Eastern Siberia; for

China, development of oil and coal deposits

and expanded exploration in Western China. In

all three cases very substantial growth in

nuclear and/or solar, hydro, and other generating sources would also be required. With

the possible exception of U.S. and Soviet coal,

none of these regions is likely to export significant energy supplies, since indigenous

growth will absorb most new capacity even

under optimistic scenarios.

The costs of achieving regional self-sufficiency would be very high. Development of

North American oil shale and tar sands, for instance, on a scale sufficient to produce oil and

gas in quantities comparable to the large commercial oilfields of today, will cost hundreds

of billions of dollars. Such development will

also be “dirty” environmentalIy, involving extensive surface-mining, and hence expensive to

clean up and to regulate.

In the Soviet Union, currently the world’s

largest oil producer, finding the capital for major energy investments during the 1980’s will

be difficult. Inefficiencies in central planning

practices are likely to be magnified as de-

“1 bid , p 669,
148 ● Solar Power Satellites

mands for consumer goods and services increase.

China’s energy production potential is not

well enough known to predict future supplies

with any certainty. Oil, coal, and oil shale are

known to be present in large quantities. Current modernization plans call for sizable

energy investments.

ENERGY-DEPENDENT AREAS

Regions without sufficient local resources

will include Western Europe, Japan, and large

portions of the (currently) developing world.

Western Europe and Japan can be expected to

invest heavily in nuclear plants, especially fast

breeders.

Unfortunately neither Western Europe nor

Japan is in a good position to exploit alternate

nonnuclear technologies to alleviate dependence on imported oil. Except for a relatively

small part of Southern Europe, average annual

insolation is low—only 1,000 kWh/m2 in Central Europe, compared to 2,500 kWh/m

2 i n

Arizona. ’ Hydroelectric resources are limited

and already extensively developed. There are

no large wooded areas to provide biomass, and

regional cropland in densely populated regions

is scarce.

It is likely that Western Europe and Japan

will try to develop assured foreign sources for

future needs. This may take the form of joint

development of capital-intensive North American energy projects, gaining through partial

ownership an assured source of supplies.

Foreign interest in U.S. coal, including investment in mines and shipping facilities, has accelerated since the 1979 rise in oil prices. 8

However, it is unlikely that national policy in

the United States and Canada will permit

extensive ownership of energy resources by

foreign countries or enterprises, or significant

exports of nonrenewable fuels, even to friendly

countries. Though the size of the capital requirements may allow for foreign participation, it will not be enough to alleviate Euro-

‘K. K. Reinhartz, “An Overview of European SPS Activities, ”

Firta/ Proceedings of SPS Program Review, Department of Energy,

April 1980, p. 79.

8See “The Coal Ships,” Washington Post, Oct. 13,1980, p, 1.

pean or Japanese shortages. Investment in or

legal control of foreign assets provides little insurance against price rises or expropriation,

when the local government is so inclined.

The underdeveloped energy-poor regions

vary greatly in their levels of development and

their degree of energy dependence. In virtually

all cases oil-price rises have seriously hampered economic growth. 9 In some instances

the increases have spurred development of indigenous sources– nuclear plants in Brazil,

Argentina, and India; biomass in Brazil;

numerous small-scale hydro and solar projects

suited for decentralized generation. It is in the

less developed countries (LDCs) that the greatest proportional surge in energy demand and

electrical usage will come over the next 50

years, rising from 12 percent’” to 31 to 35 percent of global electrical demand (see app. C).

Decentralized systems can be effective in

regions without developed utility grids and

where demand is for small units for domestic,

agricultural, and light industrial use. But the

baseload power needed for extensive growth

and modernization will be expensive and in

short supply.

ENERGY-EXPORTING AREAS

Current energy-exporters include OPEC

members as well as a few non-OPEC oil producers, such as Mexico, Malaysia, and the

Soviet Union. Over the next 50 years, many

current oil-surplus states will cease to export,

due to increased domestic consumption and/or

decreased output. The time and rate at which

current oil production in exporting countries

will diminish depends on the rate of consumption as well as future discoveries. IIASA

predicts only small increases in exporting

country production through 2030, with demand increases being met primarily by coal

liquefaction and unconventional oils. The

report emphasizes that: “The ‘energy problem,’ viewed with a sufficiently long-term and

global perspective, is not an energy problem,

strictly speaking, it is an oil problem, or, more

—

‘See Energy in the Developing Countries, World Bank, August’

1980, pp 3-6

‘“I bid , p 44.
Ch. 7—The International Implications of Solar Power Satellites ● 149

precisely, a liquid fuels problem.’’ 11 As demand grows over the next 50 years, the ability

of countries to import such fuels to make up

for local shortfalls will dwindle, and prices will

rise sharply.

In summary then, the 50-year forecast is for

an increase in demand for energy of some

three to four times, and an increase in demand

for electricity of some four to six times with

rates being somewhat higher in the currently

developing regions. These forecasts are based

on a declining rate of growth in GNP, averaging some 2.7 percent (in the low scenario) to 3.7

percent (high scenario) per year. (Compared to

a global average of 5 percent from 1960 to

1975.) In general, energy scarcity will cause

higher prices, reducing demand and increasing

supply. The question is whether future supplies

will be so high cost as to force a radical change

in Iiving standards and growth rates. Maintaining a moderate rate of growth in the developed

countries and a somewhat higher growth rate

in the developing world —to provide for population increases as well as the prospect of real

increases in living standards —will place demands on energy resources that guarantee that

energy costs will consume a larger proportion

of national income than in the past. IIASA

predicts an increase of 2.4 to 3.0 times in the

proportion of gross domestic product (GDP)

spent on energy. Even if IIASA’s projections

prove to be on the high side, future energy

sources can expect to be competitive within a

very high-cost ceiIing.

SPS Contribution

SPS could begin to provide electricity by

2010-20 and could be a substantial source of

new power within the selected 50-year period.

None of the global projections to date has considered the possible impact of an SPS system

on future energy scenarios. The rise in electrical consumption is expected to be met by

large increases in coal-fired generators and

nuclear plants. However, there are serious

problems with both methods.

Coal, like oil, is abundant only in certain

areas. Unlike oil, it is expensive to ship comI I Fjnjte wor/d, Op. cit., P 653

pared to the cost of mining (because of its

bulk), especially overseas and in areas without

extensive rail Iinks, While oil and gas are

suitable for small-scale household use, coal is

expensive to store, and prohibitively dirty to

use (especially in urban areas). And increased

burning of coal could have disastrous environmental consequences, including acid rain and

global temperature increases (see ch. 6). IIASA

predicts a 10 to 1.50 C average increase,

through 2030, depending on high or low growth

rates,

Nuclear plants are characterized by widely

publicized environmental dangers. Even if

these can be resolved, public opposition to

nuclear power, as well as the rapidly increasing

costs of building new nuclear capacity, have

already delayed the production of nuclear

generators, especially in the United States

(where alternative fuels are more readily

available than in many other countries). Furthermore, the spread of nuclear technology,

especially breeders, into more and more parts

of the world will almost inevitably make it

easier for more states to manufacture nuclear

weapons. Since uranium is concentrated in

scarce deposits, largely in North America, the

Soviet Union, and parts of Africa, many areas

will be inclined to depend increasingly on

breeders. The safeguards and restrictions set

up by the United States to prevent proliferation have been only partially successful when

the main reason for building reactors has been

prestige-they will be even less effective as

energy needs make nuclear plants essential.

For these reasons, SPS may be attractive as

an alternative to other methods of generating

electricity. In addition, unpredictable factors

such as a major nuclear accident or the failure

of alternative energy sources could spur interest in the SPS. SPS would by no means replace

coal or nuclear power within the next 50 years,

but could reduce otherwise excessive reliance

on these technologies.

Economic acceptance of an SPS system

would depend on several factors. Overall costs

of delivered power will be crucial; these must

be competitive with other systems. Perhaps

equally important would be the division of
150 ● Solar Power Satellites

these costs between developers, owners, and

users and the way these are shared between

participating countries. Development of an

SPS system would require large amounts of

capital and a high level of technical/engineering expertise. There are three distinct areas

with capital and expertise: 1 ) North America; 2)

the rest of the OECD countries (i.e., Western

Europe and Japan); 3) the Soviet Union and

Eastern Europe. Assuming that extensive cooperation between the Soviet Union and other

countries is unlikely (see p. 161), the two possible collaborators have somewhat different interests. North America has the requisite technical/industrial capacity in space transportation and related areas, but is potentially

energy rich, while Europe and Japan have increasing expertise in aerospace and face continued large energy shortfalls. If the future interest of these possible participants were estimated, North American interest would rate as

potentially moderate to high and West European and Japanese (along with some other industrialized areas–South Korea, Taiwan,

South Africa, Australia) as potentially very

high. In North America, capital and interest in

SPS would be competing with coal and synfuel

development, as well as nuclear energy; in the

rest of OECD, primarily with nuclear development. In general, development of technologies

using renewable or inexhaustible fuel sources,

(such as SPS, but also fusion, ground-based

solar, and biomass) would be preferred to

depletable ones.

The possible cooperative mechanisms for

SPS development and operation will be discussed later (see Advantages and Disadvantages of Multinational SPS, pp. 159-163). It is

important here to see that potential SPS users

with limited initial capital and expertise to

contribute to an SPS system might need special incentives to participate in buying SPS

power. A major economic consideration for

such SPS users might be the lack of direct and

indirect spinoffs from SPS participation.

Ground-based antenna construction would require large amounts of unskilled labor, but

would provide few technical or managerial

posts. The capability to participate directly in

building and deploying the satellite portion of

the system is probably beyond the reach of

most of the present LDCs over the next 50

years, so that relying on SPS power might be

seen as undercutting efforts to develop an indigenous energy infrastructure. Payments to

foreign companies for such power would be a

drain on scarce foreign exchange reserves compared to development of local resources,

which cause ripple effects in the economy.

User governments would be sensitive about

depending on a foreign high-technology energy

source, even if costs and other aspects are

favorable.

What is the potential global market for SPS?

To date, only the studies by Maurice Claverie

and Alan Dupas have attempted to estimate

this in any detail. Their recent papers12 present

a possible methodology for making SPS projections. Unfortunately, their results are based on

energy demand projections completed in 1976

and 1978 that are now considered to have considerably overestimated future electricity demand’ 13 14 (see app. C).

From these projections Claverie and Dupas

estimate the maximum demand for large electric powerplants (LEPP) (see map in app. C),

and calculate SPS demand assuming either 10-

percent or 50-percent market penetration by 5

gigawatt (CW) SPSs (see table 27).

Even allowing for the high estimates of the

energy projections used, the Claverie-Dupas

calculations must be considered very rough

upper estimates of future demand; in particular, cost comparisons with alternative sources

were not taken into account. Claverie and

Dupas attribute much of SPS’s potential attractiveness to environmental and political

factors rather than strict cost advantages. 15

—

‘*M Claverie and A. Dupas, “Preliminary Evaluation of

Ground and Space Solar Electricity Market in 2025,” 29th IAF

Congress, October 1978; “The Potential Global Market in 2025

for Satellite Solar Power Stations, ” May 1979; “Possible

Limitations to SPS Use Due to Distribution of World Population

and World Energy Consumption Centers, ” 31st IAF Congress,

September 1980

‘ ‘Edison Electric Institute, Economic Growth in the Future

(New York McCraw-Hill, 1976), pp. 215-234

“World Energy Conference, Wor/cf Energy Demand (New York:

IPC Science and Technology Press, 1978)

‘5Claverle and Dupas, “Potential Market, ” op cit., p. 4.
Ch. 7—The International Implications of Solar Power Satellites ● 151

Table 27.–SPS Market in 2020/2025 (G We)

10% of New LEPP 50% of New LEPP

CWEa WECb CWR WEC

OECD. . . . . . . . 135 75 685 365

SU/EE. . . . . . . . 40 260 195

Developing . . . 50 85 430 435

Global . . . . . . . 275 200 1,375 995

*WR - Case Western Reserve.

bWEC. World Energy Conference.

SOURCE: Adapted from Claverie and Dupas, Potential G/oba/ Market, p. 4.

Within the limits of this study the ClaverieDupas estimates using the IIASA projections

cannot be duplicated. However, by using

IIASA’S estimates of installed capacity in 2030,

a rough estimate of global demand can be

made. We can assume that 20 percent of capacity will be reserve, to guard agains t

outages, and that of the remaining 80 percent,

65 percent will be baseload. Moreover, if we

accept Claverie and Dupas’ estimate that 10

percent of world demand will be met by decentralized sources, then the global estimate of

the maximum possible demand for installed

baseload capacity in 2030 would be: 80 percent (peakload) x 65 percent (baseload) X 90

percent = (approximately) 47 percent of total

installed capacity.16 Using the IIASA estimates

(tabIe 26) of 6,320 (low scenario) to 9,845 (high)

GWe, then we get 2,970 to 4,627 GWe as the

potential demand for baseload capacity.

The amount of new capacity supplied by

SPS would depend on the percent met by SPS

as opposed to alternate generating sources. If

we assume 10-percent market penetration

there would be demand for 295 GWe (low) to

465 GWe (high); if market penetration were as

high as 50 percent (which is not probable, at

least by 2030) there would be demand for 1485

to 2315 GWe. However, it should be noted that

conventional generators built from 1990-95 on

will still be in operation by 2030; since SPS

would not be available until 2010-15, the new

capacity market will be considerably smaller

than the total demand.

The number of satellites this demand represents would depend on their size; estimates

“See: “SPS-The Implications for the Utility Industry,”

working paper for OTA workshop, July 1980, p, 12,

range from 5 GW down to 0.5 GW (see ch. 5).

Development of smaller sizes would greatly

improve the market penetration of SPS by mitigating two serious obstacles: the large size of

reference rectennas, and the problems of

inserting large blocs of power into utility grids.

Rectenna size in the 5 GW reference design

is 10 x 13 km at 350 N., including a 2 km buffer zone. Reducing the size of the design to 1.5

GW would necessitate a receiving antenna

only 6.5 X 5.5 km, lowering costs and making

siting more feasible. In European demand

centers, mostly located from 450 to 650 N.,

rectennas would need to be much larger.

Given Europe’s high population densities,

many experts have suggested placing rectennas offshore in shallow North Sea waters. 17

Similar problems would be faced in the Northeastern United States, Japan, Eastern China,

and India. Though apparently feasible, placing

rectennas offshore would add considerably to

their cost.

Even more important, a reduction in size

would enable SPSs to be used by smaller utility

grids, since utilities in developed countries do

not generally make use of single generating

units supplying more than 15 percent of the

utility’s total capacity, because of the need to

ensure against generator failure (see ch. 8).

Conversely SPSs, even in less than 5 GW units,

may be a spur to integration of utility grids in

order to make use of the SPS’s large power increments. Currently, there is widespread integration of national grids in both Eastern and

Western Europe. Western Europe has an interconnected high-voltage network, with routine

commercial exchanges of power, which is coordinated by organizations such as the “Union

pour la Coordination de la Production et du

Transport de l’Electricity.” 18 In Eastern Europe, Comecon has established an integrated

150-GW grid including all of Eastern Europe

and the Ukraine.

‘7P Q Collins, “Potential for Reception of SPS Microwave

Energy at Off-Shore Rectennas in Western Europe,” Fina/

Proceedings, p. 529.

“Arnaldo M, Angelini, “Power for the 80’s: A Challenge for

Western Europe,” Spectrum, September 1980, p. 44.
152 ● Solar Power Satellites

Successful integration of national grids is

possible only where there is an expectation of

long-term stable relations with neighboring

countries. Unfortunately, though LDCs could

benefit greatly from regional interconnections,

such expectations are rare in developing

regions where integration may be necessary to

accommodate large blocs of power, and to

share the costs of building expensive rectennas. Countries and regions with a successful

history of cooperation in other areas would be

most likely to join together for SPS integration

as well.

In many developing regions, where the bulk

of the population lives in rural areas, the

feasibility of large centralized power plants is

reduced by a lack of costly infrastructure,

especially transmission lines and end-use

capabilities. In such an environment decentralized generating capacity is preferable to

SPSs or other large plants. It has been suggeste d

19 that such countries may be able to

make use of large amounts of electricity for

producing liquid fuels, such as methanol, directly from the basic elements; such fuels can

be easily integrated into economies that currently depend on kerosene or wood for cooking and heating. However, using electricity in

this fashion would not be economically feasible. Methanol can be produced from coal at a

projected cost of $0.50 to $1 .00/gal. But at

5q/kWhr, the cost just to separate from water

the amount of hydrogen necessary to make a

gallon of methanol also lies between $0.50 and

$1.00. There would be the further expense of

providing the necessary carbon (which could

be provided from carbon dioxide taken from

the atmosphere). However, producing methanol from biomass or from coal (in which the

hydrogen, carbon, and oxygen necessary to

manufacture methanol are already present)

would be far more cost effective. A more

reasonable need for SPSs might be for energyintensive uses such as desalination of seawater or fertiIizer production. 20 These projects

might be coordinated on a regional basis.

“J. Peter Vajk, Doomsday Has Been Cancelled, Peace Press,

1978,

Z“”D. Criswell, P. Glaser, R. Mayor, et al., The Role of Space

Technology in the Developing Countries,” Space So/ar Power

Review, vol. 1,1980, p. 99.

Geographical location may also be an important factor to developing countries. If the

SPS were located in geostationary orbit, it

would cost more to beam power to areas

located far north or south of the equator.

Europe, as we have seen, is at a disadvantage;

the Soviet Union is in a similar position.

Equatorial and tropical states, on the other

hand–most of them LDCs–would be in better positions to build small-size rectennas.

Cheaper power could be an incentive to industrial development and foreign investments.

In addition, an equatorial position is optimal

for launching payloads into orbit, since the

Earth’s rotational speed at the equator (approximately 1,000 mph) is higher than at other

places on the Earth’s surface. Spaceports for

sending up SPS construction material might

profitably be located near the equator, providing benefits for the countries in which they

are placed in the form of rents, infrastructure

investments, and training of local administrators and technicians.

Earlier it was assumed that the Soviet Union,

barring some radical change in its political and

social institutions, would not participate in a

cooperative SPS venture, except with its East

European allies. As a major space power, the

Soviet Union has the ability to go it alone,

though without a global market for its product

the costs would be considerable. The Soviet

Union has a number of economic reasons to

consider an SPS system, including its increasingly remote and expensive conventional

energy resources, and the large investment it

has put into its space program (currently estimated at some 1.5 to 2 percent of GNP, compared to 0.3 percent in the United States21).

The large distances involved in providing electricity to many areas within the Soviet Union

are an incentive to develop a system in which

power can be sent directly to the area being

served, without transmission lines and without

transporting fuel long distances, The Soviet

Union has a penchant for big projects, especially when competing with the West. However, currently there is no firm indication that

“Walter A McDougall, “The Scramble for Space,” Wi/son

Quarter/y, fall 1980, p. 81.
Ch. 7—The lnternational Implications of Solar Power Satellites ● 153

the Soviet Union intends to proceed with an

SPS.

Noneconomic Interest

Any SPS system would have numerous noneconomic aspects relating to national prestige

and security, and different national and regional interests can be expected to conflict.

There are three separate “arenas” in which

such confIicts might arise.

Within OECD

Although cooperation between the United

States and other OECD allies is probable, there

would likely be a high degree of competition

centered around economic interests. Control

of any joint program, the division of responsibilities between countries, and the apportionment of economic benefits to be gained from

contracts let during R&D and construction, are

all potential problem areas. In the case of SPS,

the industries involved —aerospace and energy—are high-prestige ones in which many

countries wish to develop independent capabilities. Fear of economic and technological

dominance by the United States, or of U.S.

failure to follow through on program commitments, may be a spur to accelerated development of European or Japanese launch vehicles

and construction facilities. The ESA’s Ariane

expendable launcher program has been largely

motivated by worries about such dependence,

especially by France, Ariane’s prime mover.

Japan has announced plans for a new generation of launchers, and non-OECD countries

such as Brazil and India have built sounding

rockets and satellites. Increased competition

with the United States can be expected over

the period of SPS development.22

East-West

Development of an SPS by the Soviet Union

would have major international consequences.

Since Sputnik, each side has reacted to the actions and statements of the other. Although

space successes may no longer be seen as

proof of the superiority of one social system to

another, as Khrushchev used to claim, they are

still a vehicle for peaceful competition, and a

way of impressing allies and potential allies

with individual achievements. Because of its

scope and visibility, the SPS would be a major

symbol of successful efforts in advanced technology. “Visibility” here is meant literally: 23 a

completed SPS, even in geosynchronous orbit,

would be easily visible to the naked eye. The

impact of such an effort would be direct and

great. It is unlikely that the Soviets could allow

a U.S. or Western SPS to go unchallenged. If

they felt they could not compete successfully,

they would be likely to try to block construction by emphasizing environmental dangers or

supporting Third World demands for shared

control over orbital positions. On the other

hand, a Soviet SPS effort would encourage

U.S. projects by acting as a spur to public

opinion and raising fears of Soviet ascendancy.

North-South

Many Third World states would be antagonistic to SPS development, insofar as control

of the system rests with industrialized countries, West or East. These states would be concerned about increased economic and technical dependence on the “North,” and the

limited opportunities for meaningful participation in an SPS system. The SPS could be

charged with diverting funds from development projects and with increasing the gap between the developed and underdeveloped

worlds. International forums such as the

United Nations and its specialized agencies

could be used as foci for investigations of any

proposed SPS systems and for discussion of

legal measures to bloc them or to give the

LDCs various sorts of leverage.

Many developing countries have invested

heavily in industries such as steel and oil refining in part because of the prestige value of

such large and advanced sectors. Energy production is a prominent example–witness

atomic reactors and hydroelectric projects

such as Egypt’s Aswan Dam. The SPS could be

resented because it is unavailable to LDCs;

*’See” Jerry Grey, Enterprise (New York: William Morrow & Co.,

1979), p 225 221 bid., pp. 71-82.

83-316 0 - 81 - 11
154 ● Solar Power Satellites

only the receiving antennas could be built on

home territory with local resources. Conversely, large amounts of scarce capital might be

spent trying to buy an SPS (if they are for sale)

and the lift capacity to service it in an attempt

to “keep up” with the advanced countries.

The “South” is by no means monolithic, and,

if SPS were built, many states would be potential supporters, some because of the benefits

of less expensive electricity and others

because of the prospects for future participation. The most likely supporters of an SPS

would be energy-poor countries with a rapidly

developing urban-industrial base, such as

Brazil, Argentina, Kenya, Turkey, India, and

South Korea. Any system that reduces Western

imports of OPEC oil reduces pressure on prices

and means less expensive supplies for

vulnerable LDC importers. It has been argued

that firm plans for building an SPS would of

themselves put a “cap” on oil price rises by

sending a signal to exporters that Western imports will drop in the future. z

’

Z4HOuSe committee on science and Technology, SpS Hearings

on Ff. f?. 2335, 96th Cong., March 1979, pp 132-180,

The oil-exporting states are in a special position. An SPS would by no means eliminate oil

demand and may prove beneficial by helping

to reduce pressure on exporters to increase

production to satisfy rising export needs.

Countries with large populations and relatively

small reserves, such as Nigeria, Indonesia,

China and Malaysia, may view SPS as insurance against the upcoming depletion of their

oil supplies and may choose to invest some of

their current earnings in the hope of long-term

gains. On the other hand, exporting countries,

especially those with long-term reserve potential such as Saudi Arabia, have no immediate

use for an SPS and may be tempted to side

with other LDCs —for political and cultural

reasons — in attempts to put pressure on the

West for greater LDC control. Soviet support

for such measures could cause the SPS to

become a highly polarized issue in which the

Soviet bloc and the nonalined states seek concessions from the West— a not uncommon

phenomenon in recent international affairs.

LEGAL ISSUES

The United States and other space-capable

states are currently bound by a number of

agreements that would affect SPS development.

25 Much of existing international law has

been formulated at the United Nations (U. N.)

by the Legal Subcommittee of the Committee on the Peaceful Uses of Outer Space

(COPUOS). COPUOS has been in existence

since 1959, when it began with 24 members. It

now has 47, with membership expanding as

international interest in space matters has increased. COPUOS decisions have been made

by consensus rather than by outright voting. 26

25 See Stephen Gorove, SPS lrrternatjona/ Agreements,

DOE/NASA contract No, EG-77-C-01-4024, October 1978; Carl Q.

Christol, SPS International Agreements, DOE/NASA contract No

EG-77-C-01-4024, October 1978.

2’Eilene Galloway, “Consensus DeCISiOrlrnaklrlg of

UNCOPUOS,” )ourna/ of Space Law, vol. 7, No. 1

The most important and comprehensive of

the currently applicable agreements, all of

which have been ratified by the major space

powers, is the 1967 Treaty on Principles Governing the Activities of States in the Exploration

and Use of Outer Space, Including the Moon

and other Celestial Bodies . In 1979, COPOUS

agreed on a final version of a new treaty, the

so-called “Moon Treaty, ” which has so far not

been signed by the United States or other major powers. The Moon Treaty applies to the

Moon and other celestial bodies, but not to

Earth orbit. In addition to COPUOS, important

decisions on frequency allocations and orbital

positioning are made by the International

Telecommunications Union (ITU), a specialized U. N. agency.
Ch. 7—The International Implications of Solar Power Satellites . 155

As a new arena of human exploration, legal

norms with respect to outer space have had to

be defined. This has been done through a gradual process shaped by actual usage, the extension of existing law, and the explicit adoption

of common principles and regulations.

The outstanding international legal issues

that might affect SPS development are:

1. the status of the geosynchronous orbit,

and the source of jurisdiction over the

placement of satellites;

2. provisions against environmental disturbances;

3. the military uses of space and arrtrol implications; and

4. issues relating to the -“

facilities and ber ‘“

tion of the

kind” p“

‘Y u . . .dl

..~ct ~eiimitation bei Ider the jurisdiction of the

, y ing underneath the area cond-and outer space has never been de-

,led. In recent years a number of states

located on the Equator have claimed jurisdiction over the geosynchronous orbit on the

grounds that it is not part of “outer space” but

is determined by the Earth’s gravitation, and is

a limited natural resource requiring national

control. In December 1976 eight equatorial

countries issued the Bogota Declaration asserting their position and laying claim to the

orbital segments lying over their respective territories.

The equatorial states’ claims have been rejected by the majority of other nations—

including the Soviet Union, the United States,

27space Law se/ected Basic Documents,

2d cd,, U.S

Government Printing Office, 1978, p 26

and Western Europe —as legally and scientifically untenable. Control over the orbit by a

few states would prevent free and equitable

access to a crucial position by space-capable

countries.

The equatorial claim must be SPP - ‘ -- ‘ -

context of various attempts by tr

to gain leverage over ec~ -

activities otherwise o -

seven Bogota sig~-

Ecuador, lnd~~

(Brazil

‘ is

., torums

..Y of special

geosynchronous use

..pport among many counlikely to be discussed further when

~~ considers the definition of outer

Ace next year, 28 and when the ITU convenes

a special administrative radio conference on

orbital use in 1984 or 1985.

Even if parts of the orbit cannot be appropriated by sovereign states, there is still the

problem of allocating positions and of deciding competing claims to scarce orbital slots.

The question here is part technical and part

legal: How much space is there, and what constitutes infringement? This is dependent on the

state of technology, since “infringement” is

not so much a problem of two or more objects

trying to occupy the same place as of electromagnetic interference between nearby satellites (see ch. 8). SPS satellites would not only

be very large but would, especially if using

microwaves, radiate a great deal of energy at

radio frequencies. Each SPS would have to be

allocated a position and frequency to mini-

‘“See Gorove, SPS Agreements, op. cit., pp. 14-21; and Delbert

Smith, Space Stations: /nternationa/ Law and Po/icy, Westview

Pre~s, 1979
156 ● Solar Power Satellites

mize interference with a rapidly growing

number of satellites (see ch. 8). Many spectrum

users have worried that SPS operation would

disrupt communications and sensing tasks,

others that the initial SPSs would use up the

available electromagnetic space, preventing

exploitation by latecomers. Since the acceptable limits vary with the size and type of SPS

used, the size and type of future communications satellites, and advances in transmission technology, it is impossible to say at

this time how many SPSs could be built without unacceptable interference.

Allocation of frequencies and positions has

to date been the province of the ITU, whose

1973 convention states that stations “must be

established and operated in such manner as

not to cause harmful interference of other

members, or of recognized private operating

agencies, or other duly authorized operating

agencies which carry on radio services, and

which operate in accordance with the provisions of the Radio Regulations.”29 Whether the

ITU would have jurisdiction over noncommunications satellites such as SPSs is unclear.30 In

November 1979, at the ITU’s World Administrative Radio Conference, the United States

raised the question of allocating a frequency

position for future SPS testing; the proposal

was referred to a specialized study group for

evaluation and future decision.

Allocation decisions by the ITU have been

characterized by debate over the first-come

first-served tradition, whereby first users have

priority in the use of frequencies and orbital

slots. Newly space-capable states as well as

LDCs and others who intend to develop such

capabilities in the future have urged, since

1971, that all states have “equal rights” to frequencies and positions, and the ITU has called

both the radio spectrum and the geostationary

orbit “limited natural resources” that “should

be most effectively and economically used.” A

number of LDCs have proposed that space be

reserved for their future use. Since there is no

legal basis for permanent utilization or ownership of positions, the possibility of future

zgspace Law, Op. cit., P 87

3oGOrove, op. cit., PP. 27-33.

reallocation clearly has considerable support

among have-not states. Established users such

as the United States remain opposed to a priori

assignment of slots and frequencies. Again, the

ITU debate is part of LDC attempts to gain

leverage. SPS development could be affected

by attempts of disaffected states to block

development by denying frequency allocations, or by making consent contingent on concessions by states with the most interest in

SPS. 31

Environmental Considerations

The 1967 treaty states, in article VI 1, that

each state is “internationally liable for damage” to others caused by its activities in

space. 32 The 1973 “Convention on International Liability for Damage Caused by Space

Objects” amplifies on these responsibilities.33

Hence, SPS developers might face lawsuits

or other forms of grievance if the SPS damaged

the global or local environment. The extent of

various environmental effects is unknown and

in need of further research (see ch. 8). Even if

operation of any one SPS had no effect outside

of the state making use of it, designing a

globally marketable system to meet widely

varying national standards could add significantly to costs. The possibility of large Iawsuits

could make insurance expensive or impossible

to procure; large risks in the nuclear industry

made it necessary for the Federal Government

to provide insurance, and similar provisions

might have to be made for SPSs.

Military and Arms Control Issues

The 1967 treaty commits states “not to place

in orbit around the Earth any objects carrying

nuclear weapons or any other kinds of

weapons of mass destruction” (art. IV) and in

general to carry on activities “in the interest of

maintaining international peace and security

and promoting international cooperation and

understanding” (art. III).34 The 1977 “Conven3’ Ibid , pp. 21-33,

32 Space Law, op. cit., p. 28.

“Ibid , pp. 49-69.

“lbld , p. 26.
Ch. 7—The International implications of Solar Power Satellites Ž 157

tion on the Prohibition of Military or Any

Other Hostile Use of EnvironmentaI Modification Techniques” prohibits the activities implied, with “environmental modification techniques” defined as “any technique for changing the dynamics, composition or structure of

the Earth, including its biota, lithosphere,

hydrosphere and atmosphere.” (art. 11).35 These

general principles obviously allow for criticism

of some SPS designs as having weather modification potential, requiring restrictions or

redesign to reduce such effects. Whether an

SPS’s microwave or laser capabilities would

class it as a weapon of “mass destruction” and

hence make it illegal under the 1967 treaty is

unclear, but it is very likely that such charges

would be made in the event of SPS deployment. Development of an SPS might entail renegotiation of relevant treaties or special system design to minimize its usefulness as a

weapon.

Military satellites for communications and

remote sensing are currently used by several

countries, and presumably use of the SPS platform for such purposes would not constitute a

change in accepted practice. The Soviet Union

has tested antisatellite satellites on several occasions, and the United States and Soviet

Union have conducted informal talks (currently suspended) on limiting antisatellite

weapons. The Soviet Union has complicated

matters by stating that it considers the Space

Shuttle an antisatellite system, an unacceptable proposal for the United States. 36 U.S. Air

Force involvement in the shuttle program and

Department of Defense (DOD) plans for military missions provide Soviet negotiators with

their rationale. Insofar as the Soviet Union is

making this argument for bargaining purposes

in the absence of a similar Soviet system

(similar to Soviet proposals to ban atomic

weapons in the period when it lacked its own

and to prohibit satellite reconnaissance in the

early 1960’s) such a charge could also be made

against heavy lift launch vehicles (HLLVs) used

jSAgreernent Governing the Activities of States on the Moon

and Other Ce/estia/ Bodies, pts, 1 and 2, U.S Government Printing Off ice, May 1980, p. 256.

“’’Soviets See Shuttle as Killer Satellite, ” AviationkVeek and

Space Teclmo/ogy, Apr. 17,1978, p. 17

for shuttle construction. In the absence of

their own SPS program, obstructionist tactics

by the Soviet Union could be expected.

Although unlikely, use of the SPS for

directed-energy weaponry, either directly, or

as a source of energy to be transmitted to

remote platforms, or for tracking, would be

regulated by the 1972 Anti- Ballistic-MissiIe

(ABM) Treaty between the United States and

the US.S.R. Article V of the treaty states that

“each party undertakes not to develop, test, or

deploy ABM systems or components which are

sea-based, air-based, space-based, or mobile

land-based.”

Use of the SPS for ABM purposes would

hence be banned. Since any laser or microwave SPS is potentially capable of being so

used, the Soviet Union (or the United States if

the tables were turned) would undoubtedly insist on assurances and inspection provisions to

prevent such developments. The ABM treaty

provides for inspection and verification by

“national-technical means, ” i.e., by remote

surveillance. Onsite inspection has historically

been refused by the Soviet Union, although the

1967 treaty, and the “Moon Treaty,” include

provisions for mutual inspection of lunar and

celestial facilities. SPSs would need to be

monitored by Earth- and space-based reconnaissance means.

Although the ABM treaty is of “unlimited

duration” there has been considerable sentiment in the United States for its abrogation or

renegotiation in order to provide a defense for

America’s increasingly vulnerable land-based

ICBMS.

37 Abandonment or substantial change

in the treaty might allow for development of

directed-energy weapons in conjunction with

an SPS system. Renewed negotiations may

have to take SPS development into account,

perhaps by specifying SPS designs that make it

unusable as a weapons system. An SPS that

used lasers as its energy-transmission medium

would be particularly destabilizing and it is

possible that arms control considerations

would prevent such a system from being built.

-——

“See Carries Lord, “The ABM Question, ” Commentary, May

1980
758 ● Solar Power Satellites

Common Heritage and the Moon Treaty

The 1967 treaty states, in article 1, that “The

exploration and use of outer space . . . shall be

carried out for the benefit and in the interests

of all countries, irrespective of their degree of

economic or scientific development, and shall

be the province of all mankind.” 38 The draft

version of the Moon Treaty adds (art. IV). “Due

regard shall be paid to the interests of present

and future generations as well as to the need

to promote higher standards of living and conditions of economic and social progress and

development in accordance with the Charter

of the United Nations. ”39 The exact meaning of

these provisions is unclear, beyond a negative

duty not to interfere with the activities of other

states or to harm their interests. A positive interpretation that “would impose on space

powers the obligation either to permit other

countries to use the former’s space vehicles or

to share the financial benefits of its space activities, ”40 has been made by some LDCs but

has not received widespread support. Since

1958, U.S. policy has been to encourage international cooperation. U.S. launch capabilities

have been available to all countries, on a reimbursable basis, for peaceful and scientific purposes.

In 1970, A. A. Cocca of Argentina proposed a

draft treaty in UNCOPUOS which provided

that the natural resources of the moon and

other celestial bodies be “the common heritage of mankind.” This terminology was borrowed from similar language used in the Law

of the Sea negotiations in 1967 for regulating

seabed resources that lie outside of national

jurisdiction.

In the course of the Law of the Sea negotiations (not yet concluded) “common heritage,”

has come to mean common ownership, “by

mankind as a whole” (art. CXXXVII), 14 wit h

commercial exploitation to be regulated by a

yet-to-be-formed “international regime” which

will distribute part of the returns among participating countries. In 1970, the United States

3aSpace Law, op. cit., p. 25

39 Agreement, Op, Cit., pts. 1 and 2, PP 88

-89

‘“Smith, op. cit., p. 92.

“Agreement, op. cit., pts. 1 and 2, p 74

voted for a “declaration of principles” that

prohibited activities “incompatible with the international regime to be established.”42 Until

the regime is more clearly defined, it is impossible to tell whether current activities will

be incompatible or not. The effect of this

climate of uncertainty and of the possibility

that future regulations may make mining unprofitable has been to keep sea-bed mining

consortia —several of which were formed in

the 1970’s—from proceeding with the large

capital investments needed for commercial exploitation.

Article Xl of the draft Moon Treaty provides

for a regime (to be established sometime in the

future) with the following provisions:

1, The Moon and its natural resources are

the common heritage of mankind . . .

5. States parties to this agreement hereby

undertake to establish an international

regime, including appropriate procedures,

to govern the exploitation of the natural

resources of the Moon as such exploitation is about to become feasible . . .

7. The main purposes of the international

regime to be established shall include . . .

(d) an equitable sharing by all States

Parties in the benefits derived from

those resources, whereby the interests

and needs of the developing countries,

as well as the efforts of those countries which have contributed either

directly or indirectly to the exploration

of the Moon, shall be given special

considerate ion. 43

Moon Treaty opponents have argued that

the treaty, like the proposed Law of the Sea,

would delay or prevent commercial investment in space activities, and would in any case

substitute a state-run international body for

private enterprises.44 Because of the already

developed technology for deep-sea mining

(most of it U.S.), the Law of the Sea negotiations have become absorbed in detailed discussion of the regime to be established, while

—

“Agreement, op cit , pt. 3, August 1980, pp. 295-307

“Agreement, op cit , pts. 1 and 2, pp 91-92,

“See ‘ 1-5 Memorandum” in Agreement, op cit., pp. 377-378
Ch. 7—The International Implications of Solar Power Satellites ● 159

in the Moon Treaty such details have been left

to the time when exploitation of lunar or other

celestial resources is “about to become feasible.” The eventual outcome of the Law of the

Sea may have an important bearing on the

shape of a future outer space regime.

Since the Moon Treaty would not apply to

objects in Earth orbit, SPS would not be directly affected. However, the Treaty could have

several indirect effects. First of all, in several

scenarios large-scale SPS construction beyond

an initial demonstration system is economically feasible only if the satellites are built from

lunar or asteroidal material (see ch. 5). Such

prospects would be dependent on a regime

such as is envisioned in the Moon Treaty,

which would have to grant permission to mining companies to extract minerals and build

facilities.

Secondly, it can be argued that solar energy

is a celestial resource under the jurisdiction of

the proposed regime, and that SPSs (and other

space-craft) must be granted permission to use

it.

4 5

Though such an argument is unlikely to

find general acceptance, it could be used by

interested states to try and gain additional

leverage.

Thirdly, adoption of the Moon Treaty would

provide a powerful precedent that could affect the evolution of a future SPS project. It

would legitimize developing countries’ claims

to receive benefits on a par with states that

have actually invested in launch or construction facilities, and give impetus to arguments

that the geostationary orbit is a “common

heritage” resource requiring explicit allocation

by an international body.

In the course of the Moon Treaty negotiations the United States was a consistent supporter, along with virtually all the Third World

participants, of the common heritage provisions, while their most persistent opponent was

the Soviet Union.46 The U.S.S.R. did not accede

to these provisions until 1979. While the

United States generally interpreted common

heritage in such a way as to allow for some degree of private unilateral commercial development, the Soviet Union expressed fears

that the treaty would lead to an unacceptable

suprastate body. The Soviet position was that

such a body would infringe on the sovereign

rights of states. The Soviets have also opposed

allowing private or nongovernmental bodies to

engage in space activities. Both the 1967 treaty

(art. Vl) and the proposed Moon treaty (art.

IXV) provide for state supervision of and responsibility for the activities of nongovernmental entities. This “state-centric” approach

is typical of Soviet attitudes in international

negotiations.

As a result of concerns generated by the Law

of the Sea negotiations, as well as antitreaty

lobbying by “pro-space” organizations such as

the L-5 Society, U.S. support for the draft

Moon Treaty has been limited. U.S signature

has been discussed in the Senate Subcommittee on Science, Technology, and Space, and by

a special interagency committee chaired by

the State Department. Prospects for U.S. approval currently appear to be slight.

“Conversation with Eilene Galloway, September 1980,

—

“Agreement, op. cit., pts 1 and 2, pp 27-38

ADVANTAGES AND DISADVANTAGES OF

MULTINATIONAL SPS

No matter what country or organization

were to build an SPS, it is clear that construction would involve some cooperation with and

accommodation of the interests of other states

and regions. However, from the point of -view

of any national government— and to a lesser

degree of private corporations as well–it

would be preferable, other things being equal,
760 ● Solar Power Satellites

to build the SPS as a strictly national venture

and to own and operate the system on a unilateral basis.

Unilateral Interests

From a corporate viewpoint, it is much

easier to do business within a country than to

do so across national boundaries. Multinational ownership or control would complicate

decisionmaking, reduce flexibility, and introduce a multitude of political strains that

any company would prefer to avoid. To the extent that foreign markets are attractive, the

company wouId prefer to retain domestic ownership and to sell completed units abroad,

minimizing foreign entanglements.

From the point of view of governments that

might consider investing in SPS, the desire to

do so alone would be very strong, for reasons

of prestige, security, and economics. At present only the United States and the Soviet

Union could even consider such a unilateral effort. In the longer term, however, it is conceivable that a European consortium or

perhaps even a single European state—most

likely France– could also undertake such a

project. So could Japan, with possible cooperation from China, South Korea, and other

regional powers with technical expertise and

financial resources.

Is it likely that the United States or the

Soviet Union would build an SPS in the near

future? Such a program would be undertaken

only if there were serious doubt that alternative energy sources will be available in the

future, or that their costs will be acceptable.

This would have to mean that the C02 and environmental problems of large-scale coal use

were seen to be acute and imminent, or that

nuclear reactors were deemed unacceptable

due to a major accident and public disapproval. In addition, alternatives to the SPS

such as fusion, ground-based solar cells, and

possible other future technologies, would have

to fail to fill the gap (see ch. 6). In the event of

some such crisis SPS studies must be sufficientIy advanced to provide very high assurance

that such a system would work. Given this

combination of events, and if cooperation with

foreign governments or corporations is rejected because of fears that it might slow

down the project or otherwise reduce its

domestic usefulness, it is possible that a

unilateral effort would be undertaken.

There are several other factors that might increase the attractiveness of a unilateral crash

project similar to the Manhattan or Apollo programs. Three requirements for such decisions

are: 1 ) a crisis, requiring immediate action,

which threatens basic national interests; 2) the

existence of a workable plan to resolve the

crisis; 3) decisive leadership by persons in positions to implement such plans. ” In the Manhattan and Apollo cases, the crises involved

challenges to national interests that placed a

premium, not only on developing the atomic

bomb or the ability to go to the Moon, but on

doing so first.

The SPS would have important economic,

prestige, and security implications. Unilateral

development by the Soviet Union or the

United States would provide a strong impetus

for the other to do so as well, as long as the

project could also be justified on other

grounds. The strength of this impetus would

depend on the state of future U.S.-Soviet relations. In the 1950’s nuclear weapons and their

delivery systems were seen as vital to the existence of the state; the space programs of the

1960’s as symbolic of each state’s social and

economic superiority. It is unlikely that the

SPS would be as crucial to East-West competition as these earlier technologies, unless the

SPS or the launchers needed to build it become vital elements of military systems. For

the reasons given in the next section, Nationa/

Security Implications of SPS this is possible

but unlikely. Hence an equivalent desire to

build the first system–an SPS “race”- is improbable.

Within the United States certain interests

would favor unilateral as opposed to multilateral development. Businesses likely to benefit

from development, such as aerospace indus-

— — .

“]ohn 1 ogsdon, The Decision To Go To rhe Moon (Cambridge,

M,tss Ml T Press, 1970), p 181
Ch. 7—The International Implications of Solar Power Satellites ● 161

tries or large construction firms, might prefer a

unilateral effort that would provide them with

most or al I of the contracts, as well as the prospect of foreign sales. However, others might

fear that a unilateral development would discourage foreign buyers. Some utilities and oil

companies might oppose an SPS altogether if

it competes with energy sources in which they

have already invested. Since unilateral development would almost undoubtedly mean a

government-dominated and financed project,

such businesses would be likely to argue that

the SPS is unfairly competitive and to demand

compensation.

In the Soviet Union there is no private sector

and hence no question of public v. private

development. Though it is possible that nonCommunist states such as India and France,

both of whom have engaged in cooperative

space projects with the Soviet Union before,

might participate in small ways, it would be

unprecedented for the Soviet Union to engage

in extensive joint planning or operations with

nonallied states. Such cooperation in sensitive,

high-technology areas involving space capabilities, which in the Soviet Union are run by

the armed forces and considered top-secret

military programs, is especially unlikely.

Hence an international SPS program is not a

real option for the Soviet Union, given its present political and economic institutions.

Within both the United States and Soviet

Union, the military may argue for a unilateral

program in order to enhance SPS’s military

usefulness, which would be destroyed if sensitive information had to be shared among

neutral partners or partners who could not be

trusted not to reveal technical or other details

to unfriendly states. In the United States,

resistance to military involvement is likely to

be strong, partly to avoid foreign charges of

aggressive intent, and also to prevent possible

military interference in the project’s efficiency, as with the Space Shuttle.48 However, given

the military’s role in the Soviet space program,

“The price for Air Force support of Shuttle funding in Congress was substantial redesign of the original Shuttle model, lowering performance and increasing costs See Jerry C rey, Enterprise (New York: William Morrow & Co , 1979), pp. 66-68.

such arguments are likely to be less telling

there than in the United States. Although various Soviet ministries would seek a say in SPS

development, none has the technical or managerial competence to displace the military in

such a project.49

In the United States, the Government sponsors two largely separate space programs, a

civilian one run by the National Aeronautics

and Space Administration (NASA), and a military one run by the Department of Defense.

Both draw extensively on expertise and experience from a large number of private firms.

While an SPS project in the Soviet Union could

not help but be dominated by the military, a

U.S. project, even one run by the Government,

could be shared between the military, Government-civilian, and private sectors. Various

combinations could be developed to provide a

desirable mix between public and private, military and civilian authorities.

50 In the past,

Government-sponsored projects that might

provide guidance and precedent for an SPS

program have included the Panama Canal, the

Tennessee Valley Authority, and the Interstate

Highway System. (See ch. 9, Financing, Ownership, and Control. ) What is important is the

flexibility available to U.S. planners, a flexibility not found in the Soviet Union, which, if a

multinational effort is preferred, makes it

possible to accommodate international partners on various terms.

Both Western Europe and Japan have more

urgent requirements for reliable energy supplies than the two current space powers. The

impetus for SPS development wouId be similar

to that for the United States, but the need is

more imminent, and the costs of alternatives,

in the absence of indigenous fossil fuels, are

higher. Could an SPS be built in an acceptable

period without extensive U.S. assistance

(assuming Soviet assistance is improbable)?

“See Soviet Space Programs 1977-7975, vol. 11, ch, 2, “Organization and Administration of the Soviet Space Program, ”

August 1976, pp. 63-82.

‘°For discussions of these issues, see Peter Vajk, 5PS Financ;al/Management Scenarios, DOE/NASA contract No. EG77-C-01 -4024, October 1978, Herbert Kierolff, SPS F;nanc;al/Management Scenarios, DOE/NASA contract No. EG77-C-01 4024, October 1978.
162 ● Solar Power Satellites

The requisite technical and financial base is

available; strong aerospace industries exist; national and multilateral space programs, such

as the European Space Agency (ESA), are in

place. However, both ESA and Japan lack the

depth of U.S. industry’s aerospace expertise,

its worldwide tracking and relay networks, and

above all experience in and development of

manned space-vehicles. The most sophisticated non-American launch vehicle is ESA’s

Ariane, which is still being test-flown and is

scheduled to begin commercial operations in

1982. 5

’ The Ariane is a high-quality three-stage

expendable booster, but it is far smaller than

the large U.S. Saturn rockets used for the

Apollo program. And it is far behind the U.S.

Space Shuttle in capabilities, payloads, and

cost effectiveness (at least to LEO). Since the

Shuttle itself is too small and expensive for

full-scale SPS construction, ESA is at least two

generations of vehicles away from being able

to develop an SPS unilaterally. Producing the

requisite lift capabilities in an independent

program would be extremely costly and timeconsuming.

It is clear that any unilateral SPS program

depends on a dramatic and unpredictable increase in the sense of urgency about medium

and long-term energy supplies. Even if such an

increase were to occur, such efforts would be

very expensive for any one country or region to

undertake, especially since crash programs are

necessariIy more expensive than ordinary ones;

money is traded for time.

Multilateral Interests

There are three reasons why interested parties may wish to abandon their preference for

autonomy in favor of an international effort.

These are: 1) to share the high costs and risks;

2) to expand the global market; 3) to forestall

foreign opposition and/or promote international cooperation.

costs

The exact costs of developing, manufacturing, and operating a SPS are unknown; NASA

“Edward Bassett, “Europe Competes With U.S. Programs, ”

Aviation Week and Space Technology, Mar 3,1980, p, 89.

estimates a 22-year, $102 billion program for

the reference design. 52 (See ch. 5, Costs. ) Although the R&D costs would be much lower

than construction costs, they would be the

hardest to finance, and the ones where international cooperation would be most valuable.

The number of satellites needed for a global

system would clearly be much larger than for a

U.S. system alone. However, the R&D/prototype costs are essentially the same whether the

system is unilateral or multilateral. Since the

very long 30-year period of investment before

payback is the project’s weakest link, it would

be desirable to spread these costs between a

large number of possible investors. And by

widening the available pool of capital and expertise, an international effort would have less

of an inflationary impact on resources, thus

keeping costs down.

However, it should be realized that an international consortium, whether involving private

firms or government agencies, will tend generally to increase the overall costs. Under the

best of circumstances there are costs associated with doing extensive business across

borders, with coordinating efforts in different

languages and geographic areas, and with balancing the divergent national interests of

foreign partners. Without careful management

and a high degree of cooperation from the

states involved, these extra inefficiencies can

eliminate any advantage gained from internationalizing the project. The experience of European collaborative efforts has been that costs

rise as the large number of participants increases the managerial superstructure and

project complexity .53

The Global Market

We have previously discussed the SPS’s potential global market. An international venture

may improve the marketing prospects of the

system. First of all, potential users and buyers

wouId be less concerned about becoming dependent on a particular country or corporation, which may infringe on national sov-

.——

5

*K Ierolff, op. cit., pp. 4-5

5 JTestlmony of Dr. Wolfgang Fink, /nternationa/ Space Activities, 95th Cong., November 1978, U.S. Government Printing

Office, p 12
Ch. 7—The lnternational Implications of Solar Power Satellites ● 163

ereignty. Many states, especially LDCs, are

concerned about such a situation, particularly

with regard to U.S. firms. Over the past 15 to

20 years, LDCs have made great efforts to gain

indigenous control over local industries and

resources, often resorting to nationalization

and expropriation. The accumulation of financial and legal expertise by LDC governments

means that future dealings with foreign firms

will be more cautious and equitable than in

the past. Also, it is often politically more feasible for a neutral or nonalined state to deal with

an internationally controlled consortium than

with a U.S. or Japanese or West European firm,

especially when internal opposition to such

relationships is strong.

A consortium that offered direct participation and ownership to a large number of

states would improve its marketing position

even more. Such participation/ownership, even

if on a small scale, would help to familiarize

members with the organization’s operation

and finances, and assure potential buyers that

they were not being deceived. A financial

stake would provide an incentive to see that

the system worked efficiently and was suited

for the needs of a variety of users.

Widespread participation by many countries

with different financial stakes and energy requirements would also present a host of problems. Even small investors could be expected

to lobby for a proportionate share of the

benefits, including profits and contracts, and

for a say in policy and management decisions.

Investors with similar interests can be expected to band together. Often, small-stake

participants with less to lose are willing to use

any available forum to further ideological or

economic interests unrelated to the business at

hand. A balance must be struck between the

advantage of open participation and the danger that such participation could undermine

the organization’s credibiIity and competence.

Forestalling Opposition,

Promoting Cooperation

Because of the importance

the size of the financial stake

SPS participants could expect

of the SPS and

involved, major

that nonparticipants would use their leverage for concessions

in unrelated political or economic areas. However, mere participation would not forestall

opposition. If member interests are not mutually compatible, opposition is only moved

from without to within. The best check on internal obstructionism would be for the major

participants to indicate their willingness to go

it alone, if necessary, rather than allow internal

obstacles to destroy the project. Since organizations quickly develop their own constituencies, within and without governments,

which have an interest in maintaining the organization, a credible threat to go it alone must

be backed up by national leaders and by investment in the requisite systems.

Possible Models

Intelsat, Inmarsat

How might such an organization be constructed, and what are the types of problems

that might be faced? Here it is helpful to look

at historical examples of international organizations in the space and energy fields. We

will look briefly at Intelsat and Inmarsat; at

cooperative efforts in nuclear power; and at

the European Space Agency (ESA).

Of existing bodies, Intelsat and its nearrelative, Inmarsat, have been mentioned most

often as possible models for an international

SPS project. Intelsat is attractive because it

has been efficient and profitable, and because

it has succeeded in including a large number of

participating states.

Intelsat was founded in 1964, largely at the

prompting of the United States, to provide international satellite telecommunication services. The initial agreement provided for joint

ownership and investment in proportion to the

use of the system by each participating country, and for renegotiation in 5 years to take account of experience and new developments. 54

At first, Intelsat was dominated by the United

States through its semipublic participant, Comsat; LDC participation was minimal, and the

“Jonathan Galloway, The Po/;t;cs and Technology of Sate//;te

Communications (Lexington, Mass.: Lexington Books, 1972),

p 75
764 ● Solar Power Satellites

Soviet Union and East Bloc countries refused,

to join, preferring to establish a separate organization, Intersputnik. The permanent agreements reached in 1971 reduced Comsat control

and made it easier for low-use countries to participate. In 1979, Intelsat had 102 members,

with the U.S. share being 24.8 percent. 55 (See

app. E.)

Inmarsat is designed to provide positioning

and maritime services between ships and shipto-shore. Organized similarly to Intelsat, it is

expected to begin operations in 1981, leasing

its initial satellite services from lntelsat. 56 (See

app. E.)

Though Intelsat has functioned relatively

smoothly and has shown a good return on invested capital, serious disagreements between

participants have arisen. Many of these disagreements have revolved around the allocation of procurement and R&D contracts,

with member countries competing for prestigious and high-value shares. Given the predominant position of U.S. aerospace firms,

much of the pressure has been for equitable

shares for European and Japanese companies.

However, some participants, especially LDCs

and others without indigenous aerospace capabilities, have objected to distributing contracts on a geographical or political basis,

charging that it drives up costs.57 Non-U. S. contract shares have risen over time (23 percent of

Intelsat 5, the latest model satellite, is foreign

built), 58 and future use of ESA’S Ariane launcher and purchase of European communication

satellites may raise this significantly. (See app.

E.)

What do the Intelsat and Inmarsat model

tell us about a possible “lntersunsat?” The

relatively smooth functioning of Intelsat is

largely a result of its initial organization, which

had certain peculiarities not likely to be repeated in the future.

55 Comsat Annual Report 1979, p. 23.

“’’Operating Agreement on Inmarsat, ” 1976; in Space Law,

p. 445.

Szjoseph N, pelton, G/oba/ communications %’te//jte po/icY:

Intelsat, Politics, anci Functionalism (Mt Airy, Md.: Lomond

Books, 1974), p. 76.

‘a’’lntelsat Being Readied for November Launch,” Aviation

Week and Space Technology, Oct. 27,1980, p 51.

Above all, Intelsat came into being through

the. dominant interest and investment of a

single participant, the United States. U.S.

determination to institute a global communication satellite system was due in large part to

the Kennedy administration’s desire, at a time

when the Soviet Union seemed superior in

manned and unmanned space capabilities, to

achieve a space success before the Soviets that

would pay off in terms of global prestige and

the furtherance of U.S. national interests. The

1958 National Aeronautics and Space Act

which established NASA proclaimed that

space activities “should be devoted to peaceful purposes for the benefit of all mankind.” 59

In addition to the scientific and commercial

benefits, improved international communication was seen as a foreign policy plus for the

United States, that would involve other states

as participants under U.S. leadership. The

technology for such activities was well advanced and judged to be superior to that of the

Soviet Union.

The centralized management structure thus

created, combined with U.S. technical leadership and its status as the largest single user of

the system, gave Intelsat initial national support that was vital in allowing it to operate efficiently and with a minimum of delays. The

promise of future renegotiations placated

those, such as France, who objected to the initial phase of U.S. dominance. By contrast, the

establishment of Inmarsat, despite its close

adherence to the Intelsat model, took 4 years

of negotiations and some 9 years before the

start of actual operations.

At the outset of Intelsat negotiations in

1963, and even at the time of renegotiation in

1969-71, the U.S. position vis-a-vis Europe and

the Third World was much stronger than it has

been since or is likely to be again, not only in

space technology but in general economic performance and military strength. This acrossthe-board preeminence made palatable-a U.S.

position that would today probably not be

tolerated.

5“’National Aeronautics and Space Act,” 1958; in Space Law,

p 499
Ch. 7—The International Implications of Solar Power Satellites ● 165

In the foreseeable future, U.S.-European

equivalence in technical and economic capabilities and the increased self-confidence of

the Third World countries, who were effectively excluded from the initial Intelsat arrangements, will make a repeat of the U.S. position

impossible. With regard to an SPS, the United

States would not necessarily be the largest

user, nor would it have a monopoly on engineering expertise. And the political impetus

provided by Soviet competition, which was

vital to the formation of Comsat and Intelsat,

is likely to be missing or muted.

The swift and effective establishment of lntelsat depended on several other factors. One

was the prior existence of international and national entities dealing with global communications. Bodies such as the ITU provided technical background and legal precedents for

dealing with communication satellites, and national telecommunications agencies had long

experience with short-wave and cable transmissions. No such equivalent exists for the SPS.

The initial costs of Intelsat were comparatively low; as of 1980 (through 16 years of

operation) a total of somewhat over $1 billion

had been invested in R&D and procurement. In

addition, the basic research had already been

done, and paid for, by the United States; it was

a proven technology with a predictable market. The SPS would be several orders of magnitude more expensive, would take decades to

produce, and is far riskier. One consequence

of communication satellites’ low cost—and

the existence of established communication

entities—was that the basic decisions, both at

the beginning and later on, were made by expert bodies with little public awareness. 6o This

prevented sharp polarization and allowed

negotiators to give and take without risking

outcries at home. SPS negotiations would not

take place in this atmosphere. As one observer

notes, “An SPS is not likely to come into being

through the nonpolitical activities of technical

agencies . . . Decisions about SPS at the international level will be made . . . by the political

leaders of major nation-states in the context of

‘OPelton, op. cit., p. 44

international political debate. ”61 The large size

and importance of SPS contracts would create

strong pressures for geographical allocation;

here the experience of the North Atlantic

Treaty Organization (NATO) may be more relevant than that of Intelsat.

The above is not meant to dismiss Intelsat’s

experience. Valuable lessons from Intelsat are

the importance of corporate-style independent

management; weighted voting by investment

share and usage; and interim arrangements

that allow a project to begin work and gain experience before establishing a permanent

structure. And the positive example of Intel sat

and the experience gained in its operation will

prove helpful in the future.

Other Models

Besides Intelsat, with its distinctive combination of state and designated-entity participation, there are other possible models for

international cooperation, including: 1) jointventures by privately or Government-owned

multinational corporations, on the model of

Aramco, or the recently formed Satellite

Business Systems, jointly owned by Comsat,

IBM, and Aetna Insurance, 2) state-to-state

agreements coordinating national space programs, such as ESA and its predecessors, ELDO

and ESRO; 3) international agreements on the

development and use of atomic power, such as

Euratom; 4) U.S. bilateral arrangements between NASA and foreign agencies or companies.

PRIVATE CONSORTIUM

Agreements for joint financing and management by nationally based companies can provide extensive informal coordination across

boundaries and facilitate the raising of capital

on diverse financial markets. (See ch. 9, Financing, Ownership, and Control. ) Two major difficulties would face such an attempt. From the

company’s viewpoint the very high initial investments and the uncertain legal and regulatory constraints would inhibit commitment

without government guarantees. Many dis-

“john Logsdon, “International Dimensions of Solar Power Satellites Collaboration or Competition?” July 1980, p 3.
166 • Solar Power Satellites

cussants have concluded that public sector financing would likely be essential for any SPS

project. ’z From the state perspective, especially outside the United States, there would be reluctance to rely on private sector development

and control of energy supplies, as well as

potential antitrust problems (especially in the

United States) caused by a concentration of

companies.

ESA

Within Western Europe there have been

ongoing efforts to coordinate national space

programs so as to compete with the United

States and the Soviet Union. In the early 1960’s

two organizations were founded: ELDO (the

European Space Vehicle Launcher Development Organization), aimed at designing and

building a European launch vehicle (the

“Europa” rocket); and ESRO, (European Space

Research Organization) to conduct basic research. Both groups, and especially ELDO, suffered from a lack of direction and from

divergent national interests. ’3 Allocation of

contracts was based on the principle of “fair

return;” contributions to the organization were

in proportion to each state’s GNP, and contracts were supposed to be let in similar ratios.

This produced intense disagreements and

delays, exacerbated by cost increases which

had to be allocated evenly among the participants.

In the late 1960’s Europe began to pay increased attention to the so-called “technology

gap” between it and the United States. In 1967,

J. Jacques Servan-Schreiber’s book The Americean challenge “polemicized the U.S. economic invasion of Europe and aroused a popular interest in technology comparable to the

Sputnik aftermath in the United States.’’ 64Interest in joint space efforts increased; the

failure of ELDO to produce a reliable Europa

rocket was heavily criticized, with France and

Germany claiming their willingness to produce

it on their own.

‘*See Vajk and Kierolff for further discussion

‘

3 See Mihiel Schwarz, “European Policies on Space Science

and Technology 1960-1978, ” Research Policy, August 1979, pp.

205-242,

“Henry Nau, Nationa/ Po/itics and /nternat;ona/ Technology

(Baltimore: Johns Hopkins University Press, 1974), p. 55

The late 1960’s also produced strong pressures, as in the United States, for projects with

economic payoffs, rather than abstract research or prestige programs. After Apollo, the

United States began to look for ways to reduce

the costs of its proposed Space Transportation

System. One way was increased cooperation

with Europe. While France remained suspicious that such offers were designed to forestal I independent European programs, Germany welcomed NASA proposals for joint development as a way to gain access to U.S. technology and to use of the Space Shuttle. Hence,

whiIe France continued to emphasize launcher

development, Germany turned to production

of Spacelab for NASA.

In 1973, ESRO and ELDO were joined together as the 9-member European Space Agency. Its major projects to date have been: 1) the

Ariane launcher, a $1 billion effort which is 64-

percent French financed and flown from

France’s spaceport in Guiana, Sout h

America; 65 and 2) Spacelab, an $880 million

project, 55-percent German financed, being

built in West Germany. Other ESA projects

have included regional remote sensing, meteorological, and maritime satellites, and a regional communications satellite (L-Sat) being

developed under the guidance of Great Britain. 66

The formation of ESA has not eliminated

intra-European difficulties and the problem of

coordinating national programs. A report in lnteravia charges that “individual states are tiring of the paper-passing and consensus-seeking

that is involved in getting programs started and

keeping them alive within the framework of an

international civil-service organization.’’” One

resuIt may be a turn towards commercial alternatives. With the completion of Ariane a new

firm called Arianespace has been formed,

made up of European industries, banks, and

the French National Space Agency, to market

the launcher commercially and in competition

“’’The French Space Effort, ” Interavia, June 1979, p, 508.

“Edward Bassett, “ESA Planning New Telecommunications

Satellite,” A v;ation Week and Space Technology, Dec 31, 1979,

p 12

“’’European Space Programs: An Industrial Plea for Integrated

Effort,ll Interav;a, August 1979, p. 785,
Ch. 7—The International Implications of Solar Power Satellites ● 167

with the U.S. Space Shuttle. 68 If successful,

Arianespace will provide an example of how

an internationally financed and developed

spacecraft can be turned over to a commercial

operating group, which could be a model for

similar development of the SPS. However, allin-all the history of European collaboration

provides more “dont's” than “do’s” for a

future SPS effort.

NUCLEAR POWER

International nuclear cooperation is the

only model that compares with the SPS in its

financial and political scope, though the

security aspects of nuclear power are largely

unique. Like SPS, nuclear power is a baseload

electricity source requiring large investments

and a high degree of technical competence,

with widely perceived environmental dangers.

The overall picture of nuclear cooperation

shows a field where development and operation, though expensive, is not prohibitively so,

and where considerations of national prestige

and security are extraordinarily high. “Have”

countries have had Iittle reason to promote the

spread of nuclear technology, except as a profitable export or a form of foreign aid. The expense of initial development has been justified

as a military necessity (as in the U.S. submarine

reactor program). Cooperation is largely motivated by the need for agreed-on international

standards and regulations to prevent accidents

and inhibit proliferation. Strictly economic or

energy-supply considerations have played a

small role, except as window-dressing, while

political and competitive needs have been the

prime movers. Nuclear development in Third

World countries, such as Brazil and India, has

“’’New Commercial Organization to Take Ariane Responsibility,” Aviation Week and Space Technology Apr. 7,1980, p. 45,

been especially motivated by noneconomic

considerations. 69

Development of an SPS should not suffer

from the extreme obstacles to positive cooperation faced in the nuclear field: the military

uses would be less important, the costs much

higher, and the economic need greater. The intense politicization of nuclear development

shows an extreme case of the forces that can

come into play during the development of a

major new technology.

U.S. BILATERAL ARRANGEMENTS

The United States has been very successful

in establishing useful bilateral arrangements

with foreign governmental agencies and organizations, such as ESA. NASA has been empowered to enter into exchanges of information and services, in coordination with other

parts of Government, such as the State Department. NASA has provided launch services,

technical assistance, and remote sensing

(Landsat) imagery to a large number of foreign

customers.’” The network of relationships built

up over the years could be helpfuI in promoting a multilateral SPS. Direct bilateral cooperation with major potential partners in

Europe and Japan might be the best way to initiate foreign cooperation and create a climate

conducive to the expansion of the enterprise,

especially in the initial less expensive R&D

stages. Such agreements would take substantially less time to negotiate than regional or

global ones. ”

“June Sabato and Jairam Ramesh, “Atoms for the Third

World, ” Bu//et;n of Atomk Scientists, March 1980, p. 39.

‘“Stephen M. Shaffer and Lisa R. Shaffer, “The Politics of international Cooperation: A Comparison of U.S. Experience in

Space and Security,” Monograph Series in Wor/d Affairs, vol. 17,

book 4, University of Denver, 1980, pp. 15-26.

“Go rove, op. cit., p. 50,

NATIONAL SECURITY IMPLICATIONS

OF SOLAR POWER SATELLITES

The potential military aspects of an SPS will fears that the satellite will be vulnerable to

be of major concern to the international com- attack, or that it may be used for offensive

munity and to the general public. There are weapons (see ch. 9, Public Opinion). Such con-
168 ● Solar Power Satellites

cerns may be decisive in determining the pace

and scope of SPS development, and the mode

of financing and ownership that is used. There

are three basic aspects to consider: 1) SPS

vulnerability and defensibility; 2) the military

uses of SPS launch vehicles and construction

facilities; and 3) direct and indirect use of SPS

as a weapons system or in support of military

operations. Of these it is the second, the extensive capability of new launchers and large

space platforms, that will constitute the most

likely and immediate impact.

Vulnerability and Defensibility

There are two main segments of any SPS, the

ground receiver and the satellite proper. Since

reference-system rectennas or mirror-system

energy parks would be very large and composed of numerous identical and redundant

components, they would be unattractiv e

targets; the smaller antennas of other designs

would be slightly more vulnerable. The satellite segment would be vulnerable in the ways

outlined below, but in general no more so than

other major installations. Its size and distance

would be its best defenses.

Would SPS Be Attacked?

The reasons for attacking a civilian SPS

would be that it is expensive and prestigious,

not easily replaceable, and that it supplies an

essential commodity, baseload electricity. In

determining whether to target an SPS in the

event of hostilities, the crucial consideration

would be how much of a nation’s or region’s

electricity is supplied by SPS. In most

developed countries, utilities maintain a

reserve of approximately 20 percent of their

total capacity, in order to guard against

breakdowns and maintenance outages. If SPS

supplied no more than the reserve margin, its

loss could be made up; however, given an SPS

system consisting of many satelIites particular

regions or industries would be Iikely to receive

more than 20 percent. Making up for losses

would require an efficient national grid to

transfer power to highly affected areas.

Increased use of high voltage transmission

lines and other measures should increase U.S.

ability to transfer power. However, in many

countries, especially LDCs, SPS losses might

not be easily replaceable since SPSs, if used,

would be likely to provide more than 20 percent of total capacity on a national basis.

An attack on SPS would also depend on

other factors. If the attacker relies on its own

SPSs, it may fear a response in kind. If the

satellites were owned by a multinational consortium the attacker might be hesitant to offend neutral or friendly states involved. If they

were manned— it is unclear whether permanent personnel would be required for SPS — the

attacker might be reluctant to escalate a confIict by attacking manned bases.

The unprecedented position of the SPS,

located in orbit outside of national territory,

gives rise to uncertainties as to how an attack

would be perceived and responded to. If the

SPS is seen as analogous to a merchant ship on

the high seas, attacks would be proscribed

unless war were declared and outer space were

proclaimed a war zone. Otherwise, any attack

would be tantamount to a declaration of war.

In practice, however, experience has shown

that attacks on merchant vessels have not

caused an automatic state-of-war, though they

have often played a crucial part in bringing

one about.

It is more likely that the SPS, because of its

function and/or its stationary position (for certain designs), would be perceived as similar to

a fixed overseas base or port rather than a ship.

An attack would then be taken more seriously,

especially if lives were lost. It will be important for national leaders to clarify what status

an SPS would have, particularly in times of

crisis. A low priority assigned to SPS could encourage enemy states to attack it as a way of

demonstrating resolve or as part of an escalator response short of all-out war.

How Could SPS Be Attacked?

There are essentially five ways the satellite

portion of an SPS could be destroyed or damaged: 1) ground-launched missiles; 2) satellites

or space-launched missiIes; 3) ground or spacebased directed-energy weapons; 4) orbital
Ch. 7—The International Implications of Solar Power Satellites Ž 169

debris; 5) disruption or diversion of the energy

transmission beam.

A missile attack from the ground on a geosynchronous SPS would have the disadvantage

of lack of surprise, due to the distances involved and the satellite’s position at the top of

a 35,000 km gravity well; missiles would take

up to an hour or more to reach, geosynchronous orbit. An attack from prepositioned geosynchronous satellites would be faster and less

detectable. However, a laser or mirror SPS in

low orbit could be reached from the ground in

a matter of minutes. Lasers or particle beams,

which might be used to rapidly deface the

solar celIs or mirrors rather than to cause structural demage, would have virtually instantaneous effect.

Placing debris in SPS’s orbital path, but moving in the opposite direction —such as sand

designed to degrade PV cells or mirrors–

would have the disadvantage of damaging

other satellites in similar orbits, and of making

the orbit permanently unusable in the absence

of methods to ‘sweep’ the contaminated areas

clean. The relative ease and simplicity of this

method, however, could make it attractive to

terrorists or other technically unsophisticated

groups. Any explosive attack could have

similar drawbacks, although since the resultant debris would be traveling in the same

direction as most other satellites (which move

with the Earth’s rotation) the ensuing damage

would be SIight.

If technically feasible, disrupting SPS’s

microwave or laser transmission beam, either

by interfering directly with the beam or its

pilot signals, or by changing its position so that

it misses its receiving antenna, would be a

highly effective way to attack the SPS. Since

the effects would be temporary and reversible,

such an attack might be favored in crisis situations short of all-out war. Disruption using

metallic chaff would be ineffective against a

microwave beam, due to its very large area.

Laser beams could be temporarily deflected by

clouds of small particles or by organic compounds that absorb energy at the appropriate

frequency. Electronic interference possibilities

for lasers or microwaves cannot be presently

predicted.

A missile attack with a conventional warhead might be difficult due to SPS’s very large

size and redundancy. The most vulnerable

spot on the reference and other photovoltaic

designs would be the rotary joint connecting

the antenna to the solar cell array. Laser

transmitters would be more vulnerable due to

their smaller size, though they would also be

easier to harden. Attackers would be tempted

to use nuclear weapons, either directly on the

satellite, or at a distance. I n space a large (one

megaton or more) nuclear blast at up to 1,000

km-distance could cause an electrical surge in

SPS circuitry (the electromagnetic pulse (EMP)

effect) sufficient to damage a photovoltaic

S P S

72 (though it would have no effect on a

mirror-system). Such an attack would be particularly effective against a large SPS system,

as it could destroy a number of satellites

simultaneously. However, like an orbital debris

attack, it has the problem of damaging all

unhardened satellites indiscriminately within

the EMP radius. Furthermore, any use of

nuclear weapons would constitute a serious

escalation of a crisis and might not be considered except in the context of a full-scale

war.

Could the SPS Be Defended?

Defense of orbital platforms can be accomplished in three ways: 1) evasion; 2) hardening

against explosive or electronic attack; 3) antimissiIe weaponry.

All of the SPS designs being considered

would be too large and fragile to evade an

incoming attack. SPSs may be equipped with

small station-keeping propulsion units but not

with large engines for rapid sustained movement.

Hardening against explosive or debris attack

wouId require rigid and heavy plating. Such efforts would be prohibitively costly, except

perhaps for a few highly vulnerable areas.

‘*Peter Vajk, “On the Military Implications of Satellite Power

System s,” Linco/rI Proceedings, April 1980, pp. 506-507

83-316 0 - 81 - 12
170 ● Solar Power Satellites

Hardening against EMP bursts or electronic

warfare would require heavier and redundant

circuitry as well as devices to detect and block

jamming attacks. If incorporated in SPS

designs from the beginning, these might be

sufficiently inexpensive to justify inclusion.

Different designs may differ in their vulnerability to such attacks —the photoklystron

variation, for instance, would be less susceptible to EMP than the reference design.

Antimissile weaponry, whether in the form

of missiles or directed-energy devices, could

be placed on the SPS to defend against missile

and satellite attack. Though potentially highly

effective against incoming missiles, such

weapons would be useless against long-distance nuclear bursts or remote lasers. Furthermore, they would have unavoidable offensive

strategic uses against other satellites and intercontinental ballistic missiles (ICBMs), and

would hence invite attack. For these reasons

major defensive systems are unlikely to be

placed on civilian SPSs. Attacks would be

more effectively deterred by political arrangements and by the use of separate military

forces.

Who Would Attack?

In most instances an attack could only be

carried out by a technically sophisticated nation with its own launchers and tracking systems. Threats by such a space-capable power

against other space-capable powers —say by

the U.S.S.R. against the United States—are

possible in the context of a major crisis or actual war where the attacker is willing to risk

the consequences of its actions. Threats

against inferior or nonspace-capable states,

such as SPS-using LDCs, might be made at a

much lower crisis threshold.

It is unclear which states will be capable of

projecting military power into space over SPS’S

lifetime. It is possible that technical advances

will allow even small countries to purchase

off-the-shelf equipment enabling them to attack an SPS, in the way that sophisticated surface-to-air missiles (SAMs) are now widely

available to attack airplanes. However, it is

more probable that, over the next 50 years,

such capabilities will remain in the hands of

the larger developed nations (including a

number of countries that can be expected to

enter this category in the future).

The state of technology obviously bears on

the question of whether terrorists or criminals

could attack an SPS. Politically motivated terrorists are generally strong on dedicated manpower, not technical expertise. The SPS would

be a symbolic high-visibility target, but terrorists would be more likely to attack SPS

launch-vehicles, which would be vulnerable to

simple heat-seeking missiles, than to threaten

the SPS directly.

However, a believable threat of direct attack by terrorists or small powers could be a

spur to defensive measures such as hardening

or antimissiIe devices, which wouId not stop an

attack by a major power but might be effective

against lesser threats.

Sabotage of the SPS through the construction force, either for political purposes and/or

for ransom, could not be ruled out. Careful

screening of construction workers — who

would be few in number— can be expected,

along with supervision while in orbit. The unavoidable conditions of life and construction

in space would make it difficult, especially at

first, to smuggle explosives or sabotagedevices into orbit. However, a major expansion

into space involving large numbers of personnel would, in the long run, provide opportunities for sabotage that probably cannot now be

foreseen.

Under current conditions any installation, in

space or on the ground, is vulnerable to longrange missiles, or to dedicated terrorist groups.

Reasonable measures to mitigate threats to

SPS should be undertaken, but the dangers

themselves cannot be eliminated.

Current Military Programs in Space

At present a number of nations use space for

military purposes. The United States and

Soviet Union operate the bulk of military satellites, but China, France, and a few other countries also have military capabilities. The preva-
Ch. 7—The International implications of Solar Power Satellites • 171

lent uses involve satellites in low and high orbits for communications and data transmission, weather reporting, remote surveillance of

foreign territory and the high seas, and interception of foreign communications. The crucial character of these satellites, especially in

providing information on strategic missile

placements and launches, is such that any

future war between superpowers will undoubtedly include actions in space to destroy

or damage enemy satelIites. 73

For these reasons both the United States and

the U.S.S.R. are working to develop antisatellite (A-sat) weapons. The Soviets have in the

past tested “killer satellites” capable of

rendezvousing with objects in orbit and exploding on command. ” 75 The United States

has not yet tested A-sat weapons in space but

is developing a sophisticated orbital interceptor designed to be launched from an F-15

fighter. ” Neither system is capable of reaching

geosynchronous satelIites without being

placed on larger boosters, but such development is probably only a matter of time.

The United States and U.S.S.R. have held informal talks in the past on limiting or banning

A-sat weapons; the most recent such discussion took place in June 1979. These talks have

been complicated by Soviet claims that the

Space ShuttIe is an A-sat system. The talks are

currently “on hold. ”

An outgrowth of A-sat concern has been the

rapidly increasing interest, on both sides, in

laser and particle-beam weapons. ” Although

some have predicted that such weapons couId

be deployed within a few years (especially

lasers, whose technology is more advanced

73Clarence Robinson, “Space-Based Systems Stressed,” Aviation Week and Space Technology, Mar. 3, 1980, p. 25.

74Soviet Space Programs 1977-1975, VOI 1, staff report for Committee on Aeronautical and Space Sciences, 1976, pp. 424-429.

75Craig Covault, “New Soviet Antisatellite Mission, ” Aviation

Week and Space Technology, Apr. 28,1980, p. 20,

“Craig Covault, “Antisatellite Weapon Design Advances, ”

Aviation Week and Space Technology, June 16, 1980, pp.

243-247

77 See articles in Aviation Week and Space Technology of July

28, 1980; also Richard Burt, “Experts Believe Laser Weapons

Could Transform Warfare in 80’s, ” New York Times, Feb. 10,

1980, p. 1.

than particle beams), most experts say that, if

at all feasible, they will not be available until

the end of the decade.

High-energy lasers and particle beams are

desirable because of their speed and accuracy–light speed for lasers, an appreciable

fraction of that for particle beams–making

them ideal for attacking fast-moving targets

such as satellites and incoming missiles. They

may be deployed on naval vessels, antiaircraft

positions, and in space. Space-based directedenergy weapons ‘could theoretically attack

satellites at great distances — up to a thousand

miles — since their beams would not be attenuated and dispersed by the atmosphere.

Most importantly, they could also be used to

engage attacking ICBMs, providing an effective ABM capability that would radically

change the strategic nuclear balance. Such

uses depend on attaining very accurate aiming

and tracking, and extremely high peak-power

capabiIities.

Use of SPS Launchers and

Construction Facilities

The most important military impact of SPS

development would likely be military use of

SPS launchers and construction facilities. In

order to build an SPS it would be necessary to

develop a new generation of high-capacity

reusable lift vehicles to carry men and

materials from the ground to low orbit. A second vehicle, such as an EOTV, would probably

be used for transportation to geosynchronous

orbit.

In addition, techniques and devices for constructing large platforms and working effectively in space would have to be developed,

along with life support systems and living

quarters for extended stays in orbit.

Improved and cheaper transportation would

allow the military to fly many more missions,

orbiting more and larger satellites and servicing these already in place. New construction

techniques would enable large platforms for

communications, surveiIlance, and/or directed-energy uses to be rapidly deployed. The
172 ● Solar Power Satellites

military would have the further option of flying manned or unmanned missions.

Without SPS, advanced launch-vehicles and

construction devices may not be built or, at

best, be done so much less quickly. The military may hence have a strong interest in participating in their development, as they have

with the Space Shuttle. Whether the military

would actively support the SPS in order to

benefit from such developments might depend

on whether they think SPS funding would

direct resources away from other military programs.

An ongoing SPS construction project with a

high volume of traffic into space could provide opportunities for the military to disguise

operations or incorporate them in normal SPS

activities. Such a possibility would likely cause

any unilateral SPS project to be closely monitored by foreign observers.

The most significant use of a fleet of

military-capable SPS launchers and crews

would be in providing a “break-out” capability

whereby, in time of crisis, large numbers of

communications and surveillance satellites,

antisatellite weapons, or directed-energy platforms could be placed in orbit on short notice.

This would be similar to the way a national

merchant shipping or air cargo fleet is viewed

as a military asset, and often supported in

peacetime because of its strategic significance. Fear of such uses might be a spur to the

development of antilauncher weapons, analogous to attack submarines or merchant raiders.

Military Uses of SPS

Direct Use of SPS

The energy transmission beams of the SPS

could have direct military uses. A microwave

system in geosynchronous orbit would not

generate a beam intense enough to cause

direct damage to people or installations; it

might be enough to cause minor irritation or

panic if used against populated areas. An intense microwave beam might be used to interfere with short-wave communications over a

broad area (see ch. 5, Electromagnetic Compatibility).

Certain laser designs would be sufficiently

powerful and focused to cause some immediate damage to people and structures, but

would not be optimally designed for weaponsuse. An SPS would use a continuous laser

rather than the high peak-power pulsed lasers

needed for military missions. For such uses, increased focusing of the beam would be required, as well as appropriate tracking

mechanisms. If so equipped, a laser SPS could

be used directly against satellites and ICBMs,

and also against targets on the ground such as

ships, planes, and oil refineries. Such uses

would be greatly facilitated if a laser SPS were

placed in low orbit, with energy relayed to the

ground via geosynchronous mirrors. Since a

sun-synchronous SPS in low-Earth orbit would

of necessity pass directly over many different

countries (including the Soviet Union), it could

be seen as potentially more threatening than a

geosynchronous satellite that remains fixed

above one spot. A geosynchronous laser might

have difficulty tracking low-flying ICBMs and

satellites, due to its position 35,800 km from

the target.

Since the key requirement for directedenergy weapons is a large power supply, any

SPS that generates electricity directly [i.e., any

design except the mirror-system) can be used

to power such weapons. These weapons could

be built into the SPS platform or placed at a

distance in lower orbits and supplied by lasers

from the SPS. The question is whether relatively small directed-energy weapons can be

designed with autonomous power supplies,

perhaps from nuclear reactors. Since weapons

used against ICBMs must be capable of firing a

large number of very rapid bursts in order to

engage a fleet of 1,000 or more missiles, it may

be that SPS power, if available, would be the

most efficient and economical way to supply

future laser or particle-beam platforms.

Direct use of the SPS in this way would of

course make attack in time of war inevitable.

Extensive defensive armament would have to
Ch. 7—The International Implications of Solar Power Satellites • 173

be built in; the offensive weaponry could also

be used to defend against missile attacks.

Any testing, deployment, or use of directedenergy weapons in space is presently prohibited by the 1972 ABM Treaty and other space

treaties. A proposed SPS would probably be a

topic of future arms control negotiations to

clarify and limit its military implications (see

discussion on pp. 156-1 57).

Indirect Military Uses

In addition to these direct uses, a laser SPS

could be used to supply power to military

units, providing increased mobility to ground

forces that could dispense with bulky fuel supplies in remote and roadless areas. Given adequate tracking capability it might even be possible to supply mobile units such as ships,

planes, or other satellites equipped with

thermoelectric converters, increasing their

range and allowing them to carry more armaments or cargo. 78

A geosynchronous SPS is at an advantageous position for numerous communications

and positioning uses, military as well as

civilian. Its large size would make it easy to

attach equipment to it; the military’s need for

redundancy makes it convenient to use all

available platforms, as does future crowding

of geosynchronous positions. Operation of a

microwave SPS, however, could interfere with

communications uses unless switched off.

SPS’s power and position might make it

suitable for electronic warfare uses, such as

jamming enemy command-and-control links.

This would require the addition of specialized

equipment.

The mirror designs use reflected sunlight

rather than energy transmission beams. However, it has been suggested that the reflected

light could be used for weather modification

or for nighttime battlefield illumination. The

“See Michael Ozeroff, SPS Military Implications, DOE/NASA

report, October 1978, pp. 13-1 6; also A Hertz berg, K Sun, and

W. Jones, “Laser Aircraft,” Astronautics and Aeronautics, March

1979, p. 41,

energy levels are not high enough, in current

designs, to change weather patterns significantly (see ch. 8, Environment). Such use would

be prohibited by the 1980 “Convention on the

Prohibition of Military or any Other Hostile

Use of Environmental Techniques.”

Nighttime illumination could be significant,

especially in cases of guerrilla warfare or urban terrorism where attacking forces rely on

darkness and surprise as equalizers. However,

fragile Solares mirrors could probably not be

adjusted quickly enough to deal with sudden

military developments; rapid deployment of

mirrors by the military for specific uses would

probably be more effective.

Ownership and Control

Any of the military uses discussed clearly depend on who owns, operates, and builds the

SPS system. If SPSs are unilaterally owned by

national governments, their military use is far

more likely than if run by private enterprise or

by a multilateral consortium. Fears of military

involvement could be an incentive to establishing a multinational regime to operate or

regulate SPSs, and to prohibiting militarily effective SPS designs.

A key question would be who has effective

control over SPSs in a time of crisis. If a private

SPS consortium, having its own launchers and

crews, has a monopoly on SPS control and

expertise, then governments might be hardpressed to take over SPSs on their own. A

limited defensive capability would help to

deter any national takeovers. However,

governments might stipulate that in a n

emergency they be allowed to commandeer

SPSs for defense purposes.

A nongovernmental owner can be expected

to resist any attempts to use SPSs for military

functions rather than supplying electricity to

commercial users. The threat of Iawsuits or

diplomatic protests at electricity interruptions

caused by military preemption might help to

deter such actions.
174 ● - Solar Power Satellites

FOREIGN

Interest in SPS has been expressed outside of

the United States, especially in Europe but also

in Japan, the Soviet Union, and some developing countries.

●

●

●

●

Europe

The first significant European study of SPS

was done in 1975 by a German firm under

contract from West Germany’s space research organization.

In England, the Department of Industry

funded a study, completed in early 1979,

that led to a further effort by British

Aerospace to investigate the implications of

SPS for British industry. ”

In France, the work of Claverie and Dupas

on global demand for SPS has already been

mentioned.

The ESA began SPS assessments in 1977,

publishing a-number of papers in the ESA

Journal of 1978. Ruth and Westphal performed a study in 1979, 80 which examined

offshore sites for rectenna placement, and in

1980 a major report on ground receiving stations was published by Hydronamic B.V. of

the Netherlands.81 In 1978, Roy Gibson, then

director of ESA, said ESA was “intensely interested” in SPS,82 and ESA has supported a

group within the IAF for SPS investigation.

In June 1980, an International Symposium

on SPS was held at Toulouse, France, with

representatives from many European countries and agencies.83

In general, the European studies have focused on the European requirements for possible contributions to an SPS system. Little

“K. K, Reinhartz, “An Overview of European SPS Activities,”

in Firra/ Proceedings of the SPS Program Review, U.S. Department

of Energy, July 1980, pp. 78-88.

80J. Ruth and W. Westphal, “Study on European Aspects of

SPS,” ESA report No CP(P) 1266.

“A. R. Bresters, “Study on Infrastructure Considerations for

Microwave Energy G round Receiving Station,” Hydronamic Project, p, 495, November 1980

‘*In Jerry Grey, “The Internationalization of Space, ” Astronautics and Aeronautics, February 1979, p 76

83 See Peter Glaser, “Highlights of the International Symposium on Solar Power Satellites,” July 1980,

INTEREST

detailed work on the system proper has been

done outside of designs to reduce the size of

rectennas; European participants have relied

on U.S. projects for technical information.

Suspension of NASA/ DOE research efforts due

to lack of fiscal year 1982 funding will have an

adverse effect on foreign studies and has led to

great disappointment among foreign SPS experts. 84 A major difference between U.S. and

European efforts is that while in the United

States SPS has attracted interest from energy

experts and the DOE, European studies have

been the exclusive province of organizations

involved in space research .85

Soviet Union

The Soviets have initiated no major known

studies of SPS, though there have been unverified claims of a Soviet SPS project. It is impossible to tell with certainty what the degree

of interest or expertise is; U.S. experts feel the

Soviets are relying on Western reports and are

far from developing the launchers, microwave

transmission expertise, and advanced solar

cells necessary to consider an SPS. 86 Recent

signs of interest include a paper entitled

“Satellite Power Stations” published by scientists from M.V. Lomonosov State University,

Moscow in December 1977.

8788 At the 30th

Congress of the IAF in Munich, September

1979, the Solar Power Bulletin reported that:

“Although the Soviets were reluctant to disclose their level of commitment to a solar

power satellite program, Chief Cosmonaut

Beregovoy commented ‘that if the United

States puts up an SPS first, we will congratulate you, and if ours goes up first, we will

expect congratulations from you’. ”89

“Conversation with Jerry Grey, of the Al AA, Oct. 15,1980.

“K K Relnhartz, op cit., p 80

““Conversations with James Oberg, Johnson Space Center,

and Charle\ Sheldon I I, Congressional Research Service, September 1980

“ 5ovlet fpace Programs 1971-/975, VOI 1, staff report, Library

of ( ongres~, 1976, p 529

““See statement of Peter Claser In House Hearings on SPS, 96th

Cong , March 1979, p 218

““5pace \o/ar Power Bu//etin, Sunsat Energy Council, February

1980, p 1
Ch. 7—The International Implications of Solar Power Satellites ● 175

Japan

The Japanese have expressed interest and

funded studies within the National Space ’Development Agency, though no permanent office for SPS exists. Japanese interest in space

exploration and industrialization is strong and

includes plans for several new series of

Launchers. go

Third World

Information about SPS has been spread to

the Third World by discussions at COPUOS

and by sessions on SPS at international conferences such as those of the IAF. Reaction has

generally been cautiously optimistic. At the International Symposium in Toulouse, Dr. Mayur

of India’s Futurology Commission claimed:

“There is no conflict between small scale

technologies and the SPS.” Dr. Chatel, former

Chief of the UN’s Office of Science & Technology, proposed an international working

party to coordinate national programs and perform assessments. ” The SPS has been placed

on the agenda of the upcoming U.N. energy

conference in Nairobi in the summer of 1981.

‘“James Harford, “Japan Showcases Crowing Space Prowess,”

Astronautics and Aeronautics, December 1980, pp. 120-125. ‘

l Glaser, op cit

It is crucial

projections as

STUDY RECOMMENDATIONS

to continue updating long-term development and foreign military space pronew information becomes avail- grams, and arms-control negotiations.

able about developments in the space and

energy fields. Close attention should be paid

to: 1 ) future global electricity demand under

various scenarios and on a detailed regional

basis; 2) evaluation of the impact that possible

external events —wars, oiI embargoes, widespread famine— couId have on U.S. and European energy needs; 3) the feasibility of a

unilateral SPS System given a global market,

including estimates of profitabiIity; 4) monitoring of Law of the Sea negotiations and the resulting international regime with special attention to the implications for the Moon Treaty

U.S. energy and space experts often tend to

pay little attention to the foreign implications

of their programs. Since SPS is a system that

may make sense globally but not domesticalIy,

neglect of the international dimension could

lead to an unjustified foregoing of SPS development. In making plans for future R&D programs, attention should be paid to involving

and informing potential partners as well as to

considering the ways in which a global system

might differ, technologicalIy and institutionalIy, from a domestic one.

and other space agreements; and 5) weapons
Chapter 8

ENVIRONMENT AND HEALTH
Contents

Page

Introduction . . . . . . . . . . . . . . .. ....179

Environment. . . . . . . . . . . . . . . . . . . .. ...182

Power Transmission Effects on the

Atmosphere and Weather ...18 2

Atmosphere . . . . . .18 3

Space Vehicle Effects.. . . . ..18 7

Electromagnetic Interference . ......190

Terrestrial Activities. . .......19 6

Receiver Structure: Weather

Modification . . . . . . . . .. ....205

Health and Ecology . . . . . . . . ........207

Terrestrial Effects . . . . . ........20 7

ionizing and Nonionizing Radiation

Defined. . . . . . . . . . . . . . ........209

Space Environment. . . .. ....221

LIST OF TABLES

Table No. Page

28.

29.

30

31

32

33

34

35.

36.

37.

38.

39,

40.

41.

Summary of SPS Environmental

Impacts . . . . . . . . . . . . . . . .....180

Major SPS Environmental

Uncertainties . . . . . . . . . ....,.182

Power Transmission Impacts. . . . . . . .184

SPS Space Transportation Vehicles. ...188

Exhaust Products of SPS Space

Transportation Vehicles . . . ......189

Space Vehicle Impacts , .......18 9

Summary of Electromagnetic Effects. .192

SPS Systems Land Use. . . . . . ......198

Summary of Land Requirements. .. ...199

Summary of Environmental Impacts of

Rectenna Construction and Operation

at a Specific Study Site . . . . . 203

Summary of Materials Assessment

Results . . . . . . . . . . . . . . . . . . ......205

Annual Environmental Effects of SPS. .206

Terrestrial Health and Ecological

Impacts. . . . . . . . . . . . . . ......208

Characteristics of Exposure to

Reference System Microwaves . . . . . . .211

42

43

44

45

46

47

48

49

Microwave Exposure Limits .

Research Needs To Help Reduce

Uncertainties Concerning Public

Health Effects Associated With

Exposure to SPS Microwaves Power

Densities and Frequency. .

SPS Development . . . .

Estimated Sound Levels of HLLV

launch Noise . . .

.21 2

.21 3

.21 7

.22 0

Representative Noise Levels Due to

Various Sources . . . . . . . . .220

Community Reaction to HLLV Launch

Noise~ . . . . . . . . . . . . . . . .. .221

Sonic Boom Summary. . .221

Types of Radiation Found in the

Different SPS Orbits . . . . . . . . . . . . .223

LIST OF FIGURES

30.

31.

32.

3 3.

34.

35.

36.

37.

38.

39.

40.

41.

42.

43.

Regions of the Atmosphere. . . . .183

Examples of SPS Microwave

Transmission Effects on the

Ionosphere and Telecommunication

Systems. . . . . . . . . . . . . . .184

Summary of SPS Atmospheric Effects, .188

Receptor Site Protection Radius as a

Function of the Perimeter laser PowerDensity Level. . , . . . . . . . . .197

Microwave Power Density at Rectenna

as a Function of Distance From

Boresight. . . . . . , . . . , . . .197

Rettenna/Washington, D.C. Overlay. . .198

Offshore Summary Map . . . . . . . . .200

Satellite Power System — Societal

Assessment . . . . . . . . . . . . . . .201

Regional Generation and

Rectenna Allocations . . . . . .202

The Electromagnetic-Photon Spectrum, 209

SPS Microwave Power-Density

Characteristics at a Rectenna Site. .. ..211

Comparison of Exposure Standards . .. 216

Program Funding. . . . . . . . . . . .216

Factors Pertinent to Space Worker

Health and Safety . . . . . . . . . . . . . . . .. 222
Chapter 8

ENVIRONMENT AND HEALTH

INTRODUCTION

As a large-scale energy system operating in

both the space and terrestrial environments,

the solar power satellite (SPS) is unique. And

because it is a new concept, our understanding

and experience of a number of the environmental impacts associated with SPS are limited. The great uncertainties surrounding these

effects make comparisons between SPS and

other energy technologies especially difficult.

While one advantage of SPS is that it would

avoid many of the environmental risks typically associated with conventional energy options such as coal and nuclear, it also would

generate uncommon environmental effects

that presently cannot be quantified or compared to those of other powerplants. The large

uncertainties also tend to provoke public debate. In light of past controversies over the

siting of powerplants, transmission Iines and

other facilities, it is clear that environmental

issues could play a key role in public consideration of SPS (see ch. 9).

This chapter will outline the environmental

and health impacts of SPS that are currently

thought to be most important. It will identify

research needs and highlight areas of controversy. As with other aspects of SPS, the environmental effects have been evaluated most

fully for the reference system. Some of this

data is also applicable to the other SPS technical options, differing only in extent or

degree, but information on the full range of

their environmental effects is limited.

At the current stage of development, SPS environmental studies can play an important role

in determining concept feasibility, technical

design, and cost. For example, bioeffects research might influence the choice of frequency which, in turn, couId determine hardware

design and Iand use. Thus, many of the effects

currently identified might be minimized by appropriate choices of design. However, it is also

possible that one or more risks might be identified in the development process that could

not be reduced to an acceptable level without

jeopardizing the economic or technical viability of the SPS concept.

The SPS environmental effects and the cost

of reducing them must be viewed in the context of energy technologies, energy needs,

other space activities, and the incremental

effect on human health and the environment.

Preliminary comparative assessments indicate

that, in general, those health and environmental impacts of the reference system SPS

that can presently be quantified would probably be no more severe than for other largesc aIe electricity generating technologies

although the uncertainties for SPS ar e

high). 1 2 3 4 I n fact, when compared to coal,

SPS would be an order of magnitude cleaner

(see app, D). However, if an SPS program is

pursued, further comparative analysis between

energy options would be required as more is

learned about the unquantifiable impacts that

could not be incorporated in the present

studies A good portion of this chapter discusses these latter effects for SPS.

The discussion in this chapter relies heavily

on the data and analysis generated by the Department of Energy (DOE) 5 and the National

Academy of Sciences (NAS). 6 7 The reader is

——-. ——

11 j Ha begger, J R Gasper, and C D Brown, Hea/th and Safetv Pre/lrnlrtary Cor-nparatlve Assessment of the Sate//ite Power

$vstem / SPS) and Other Energy Alternatives, DOE/NASA report

No DO I IF R-0053, April 1980

‘CI t Newsom and T D Wolsko, Pre/irnfnary Comparative AsSCJS smen t o t Land Use for Satellite Power Systems and A Iternatl ‘.te

F /ectrlc t nergy Technologies, DOE/NASA report No

[ )OE I R-0058, April 1980

‘D A Kellermeyer, C/imate and Energy: A Comparative Assessment of the SPS and Other Energy A /ternatives, DOE/NASA report

No DO} F R-0500, January 1980

‘F P Levine, M J Senew, and R R Clr[llo, Comparativ e

Assessment of Environmental Welfare Issues Associated With the

\ate//lte Power System and Alternative Technologies, DOE/NASA

report ho [)OE/E R-0055, April 1980

5Envlronmenta/ Assessment for the Sate//ite Power System Concept Development and Evacuation Program, DOE/NASA report

No DOt /E R-0069, August 1980

“Comrnlttee on Satellite Power Systems, National Researc h

( ounc!l Open Committee Meetings Jan 31-Feb 1, 1980, Apr

910, 1980, j U Iy 1-2, 1980, Oct 1-2, 1980

‘(’ H l>odge (rapporteur), Workshop on Mechanisms Under/y179
780 ● Solar Power Satellites

referred to the DOE documents for more detailed discussions. While those studies have

not identified any environmental reasons not

to continue with SPS development, it is very

evident that much more study and research

(continued from p. 179)

Ing Effects of Long-Term, Low-Level, 2450 MHY Radiation on

Peep/e, organized by the National Re\ear( h (-ouncil, Committe e

on Satel I Ite Power Systems, E nvlrontmental Studms floard, N a

tlonal Academy of Sciences, July 17-17, 1980

would be required before decisions could be

made regarding the environmental viability of

SPS. What is not clear is how long it might take

before our confidence in the resolution of

some environmental impacts such as microwave bioeffects would be high enough to

make development or deployment decisions.

As table 28 illustrates, there is a great diversity of environmental and health impacts. Of

Table 28.—Summary of SPS Environmental Impacts

System component

characteristics Environmental impact

Power transmission

Microwave —b

lonospheric heating could

disrupt telecommunications.

Maximum tolerable power

density is not known

Effects in the upper

ionosphere are not known

—Tropospheric heating could

result in minor weather

mod if i cat ion

—bEcosystem: microwave bioeffects (on plants, animals,

and airborne biota) largely

unknown; reflected light

effects unknown

—b

potential interference with

satellite communicant ions,

terrestrial communications,

radar, radio, and optical

astronomy

Lasers —Tropospheric heating could

modify weather and spread

the beam

—Ecosystem: beam may

incinerate birds and

vegetation

—

b

potential interferenc e

with optical astronomy,

some interference with

radio astronomy

Mirrors —b

Tropospheric heating

could modify weather

—Ecosystem: effect of 24-

hr light on growing

cycles of plants and circadian rhythms of animals

— 

b

potential interference

with optical astronomy

Public health and safety —

—bEffects of low-level

chronic exposure to microwaves are unknown

— Psychological effects of

microwave beam as weapon

—Adverse esthetic effects

on appearance of night sky

Occupatlonal health

and safety

—Higher risk than for

public; protective

clothing required for

terrestrial worker

—Accidental exposure to

high-intensity beam in

space potentially severe

but no data

—Ocular hazard? —Ocular and safety

—Psychological effects of hazard?

laser as weapon are

possible

—Adverse esthetic effects

on appearance of night

sky are possible

——

—Ocular hazard? —Ocular hazard?

—Psychological effect of

24-hr sunlight

—

bAdverse esthetic effect s

on appearance of night

sky are possible

Transportation and

space operation

Launch and recovery

HLLV

PLV

COTV

—Ground cloud might pollute

air and water and cause

possible weather modification; acid rain

probably negligible

—bWater vapor and other

—Noise (sonic boom) may —bSpace worker’s hazards:

exceed EPA guidelines ionizing radiation

—Ground cloud might affect (potentially severe)

air quality; acid rain weightlessness, life

probably negligible support failure, long

— Accidents-catastrophic stay in space,
Ch. 8—Environment and Health ● 181

Table 28.—Summary of SPS Environmental Impacts—Continued

—— —

System component Occupational health

characteristics Environmental impact

POTV launch effluents could

deplete ionosphere and

enhance airglow. Resultant disruption of communications and satellite

surveillance potentially

important, but uncertain

—b

possible formation Of

noctiIucent clouds in

stratosphere and mesosphere; effects on climate

are not known

—bEmission of water vapor

could alter natural

hydrogen cycle; extent and

implications are not wellknown

—bEffect of COTV argon ions

on magnetosphere and

plasmasphere could be

great but unknown

—Depletion of ozone layer

by effIuents expected to

be minor but uncertain

—Noise

Terrestrial activities

Mining —Land disturbance

(stripmining, etc.)

—Measurable increase of

air and water polIution

—Solid waste generation

—Strain on production

capacity of gallium

arsenide, sapphire, silicon,

graphite fiber, tungsten,

and mercury

Manufacturing —Measurable increase of

air and water pollution

—Solid wastes

Construct ion —Measurable land

disturbance

—Measurable local increase

of air and water pollution

Receiving antenna —b

Land use and siting—

major impact

— Waste heat and surface

roughness could modify

weather

High-voltage —b

Land use and siting—

transmission lines major impact

(not unique to SPS) —bEcosystem: bioeffects of

powerlines uncertain

Public health and safety and safety —

explosion near launch construction accidents

site, vehicle crash, toxic psychological stress,

materials acceleration

—Terrestrial worker’s

hazards: noise, transportation accidents

—Toxic material exposure —Occupational air and

—Measurable increase of water pollution

air and water pollution —Toxic materials exposure

— Land-use disturbance —Noise

—Measurable increase of —Toxic materials exposure

air and water pollution —Noise

—Solid wastes

— Exposure to toxic

materials —

—Measurable land —Noise

disturbance —Measurable local

—Measurable local increase increase of air and water

of air and water pollution pollution

——.. —Accidents

—b

Land use— reduced — Waste heat

property value, esthetics,

vulnerability (less land

for solid-state, laser

options; more for reference

and mirrors)

—

bExposure to high light intensitity —bExposure to high

EM fields—effects intensity EM fields—

uncertain effects uncertain

al mpacts based on sps systems as currently defined and do not account for offshore rece!vers or possible mitigating sYStem rnodificatlons

bResearch priority.

SOURCE: Office of Technology Assessment
182 ● Solar Power Satellites

most concern are: 1) the biological effects of

electromagnetic radiation produced by the

power transmission and distribution systems;

2) the atmospheric effects of electromagnetic

radiation and launch effluents and the resulting impacts on telecommunications and air

quality; and 3) the land requirements and siting

considerations for ground-based receivers. The

greatest environmental uncertainties are Iisted

in table 29.

The first part of the chapter will deal with

the potential environmental impacts resulting

from the construction and operation of SPS

systems. These and other effects will then be

addressed in the second section as they pertain

to human health and ecosystems. Detailed discussion of a number of impacts is found in appendix D.

Table 29.—Major SPS Environmental Uncertainties

Reference and solid-state systems

●

●

●

●

Microwave bioeffects -

—Low-level, chronic exposure

Launch effluent effects

—Ions in the magnetosphere

—Natural hydrogen cycle

—Ionospheric depletion

—Noctilucent clouds

Microwave heating of the ionosphere

Effects on telecommunications

Land use

Laser system

● Laser bioeffects

. Tropospheric heating

● Launch effluents

• Land use

Mirror system

● Weather modification

• Land use

● Biological and psychological effects of 24-hr light

Systems comparisons

SOLi~~E Of~c;of Technology Assessment

ENVIRONMENT

One of the consequences of constructing

and operating an energy system in space is that

the extent of the environment that is directly

affected by the system is much broader than

for Earth-based powerplants. For example,

both the transmission of SPS power and the injection of launch effluents will directly affect

every layer of the atmosphere. The purpose of

this section is to discuss the state of knowledge

of the predominant environmental impacts of

SPS, especially those that are fairly unconventional and to outline areas where further research would be needed. Biological effects,

i.e., human health and safety and ecological

impacts, are deferred to the second part of the

chapter.

The two major environmental concerns at

the present time are: 1 ) the effect on the atmosphere of the transportation and power

transmission systems; and 2) electromagnetic

interference with communications systems

and astronomy.8 With respect to the former,

the effluents emitted from the launch vehicles

8Program Assessment Report, Statement of Findings, Satellite

Power Systems Concept Development and Evaluation Program,

DOE/NASA report No DO E/E R-0085, November 1980

couId deplete portions of the ionosphere, alter

the natural hydrogen cycle and magnetosphere dynamics and modify weather and air

quality near the launch site. The effects of the

power transmission system on the atmospb”

are a function of the frequency of the

For the laser and mirror systems, the mo~

nificant potential impact is heating of

near-Earth atmosphere, which might alter

weather. If the microwave beam were to alt

the ionosphere, it couId disrupt telecom

mu n i cat ions.

In order to understand clearly these and the

other more conventional environmental impacts described in this chapter, it is worthwhile

to review the properties and structure of the

atmosphere as illustrated in figure 30 and discussed in box A.

Power Transmission Effects on

the Atmosphere and Weather

Current SPS designs transmit energy to Earth

using microwaves, lasers or reflected light.

Since the atmospheric effects of power transmission are highly frequency dependent, each
Ch. 8—Environment and Health ● 183

Figure 30.— Regions of the Atmosphere

Solar radiation excites, disassociates and ionizes atmospheric constituents. The ionosphere in particular is a region of marked abundance of free

electrons and ions. The properties of the ionosphere vary with latitude,

time of day, season and solar activity. When electromagnetic waves enter

the ionospheric plasma, they will be refracted and slowed down. Depending on the frequency of the incident wave and properties of the ionosphere,

the wave can be totally reflected. It is this phenomena that makes many

radio frequency communication systems possible.

100

10

1

Regions of the atmosphere

SOURCE: Program Assessment Report, Statement of Satellite Power

Systems Concept Development and Evaluation Program, DOE/NASA

Report, November 1980

of these will be discussed separately. Table 30

summarizes the impacts of most concern.

Microwaves’

As the beam from a microwave satellite

traveled towards Earth, it would heat the atmosphere. While attenuation of the microwave beam by clouds and rain in the troposphere could

cloud dynamics

cause a slight modification of

 and precipitation, 9 absorption

 op 
784 • Solar Power Satellites

Table 30.—Power Transmission Impacts

Microwaves

Upper ionosphere telecommunications effects unknown;

experiments and improved theory are needed

Lower ionosphere impacts are thought to be negligible

for a number of telecommunications systems; scaling

laws must be verified and effects on telecommunication

systems operating in the 3 MHz to 20 MHz range must be

tested

The maximum power density for which telecommunications effects are insignificant is not known and must be

determined

Tropospheric heating is not thought to be significant

Lasers

● Thermal blooming in the troposphere may degrade the

beam

● Tropospheric heating may cause increased cloud formation, turbulence and weather modification

● Effects on the mesosphere, stratosphere, and thermosphere and continental cloud distribution and albedo

are thought to be inconsequential

Reflected light

● Weather modification in vicinity of ground sites is possible, but unquantified

. Photochemistry of the ozone layer is not thought to be affected

SOURCE: Office of Technology Assessment.

of microwave energy is most important in the

ionosphere. Of particular concern are the effects of ionospheric heating on telecommunication systems that rely on the ionosphere to

transmit and reflect radio waves. Changes in

the ionospheric properties due to heating can

degrade (or in some cases, enhance) the performance of telecommunication systems by

absorbing or scattering the radio signals (see

fig. 31). Specifically, these effects could result

in losses, fading, and scintillation of the electromagnetic signals. It is also possible that the

SPS pilot beam itself could be affected by the

heated ionospheric layers.

In the course of the DOE assessment several

experiments were conducted to test the extent

of heating and the effect on telecommunications in the lower ionosphere. These experiments demonstrated that while heating does

occur the effects are not serious for the teleFigure 31 .—Examples of SPS Microwave Transmission Effects on the Ionosphere

and Telecommunication Systems

F-region

ion

SOURCE: Prograrn Assessment Report, Statement of Findngs, Satellite Power Systems Concept Development and Evaluation Program, DOE/NASA Report, DOE/ER-0085, November 1980
Ch. 8—Environment and Health ● 185

communication systems tested. Some researchers have even suggested that the proposed power density of 23 mW/cm2 could be

doubled without significant impact to telecommunications in the lower ionosphere.

However, more research is needed in order to

determine the power density threshold in the

lower ionosphere, and for this the power density of the existing heating facilities will have to

be increased. Additional study is also required

to ascertain the effects in the lower ionosphere

on telecommunication systems that operate at

frequencies greater than 3 MHz (i.e., 3 to 100

MHz) range. In addition the effects of multiple

microwave beams need to be determined.

Our knowledge of upper ionosphere (F region) heating is less advanced than in the D & E

regions. Few underdense experiments (i. e., the

beam travels through the region as opposed to

being reflected, which is termed an overdense

condition) to simulate SPS heating have been

attempted. Recent experiments’ 2 suggest that

ionospheric irregularities can be created when

the Platteville heater operates in an underdense mode and that these irregularities induce scintillations in very high frequency satelIite-to-aircraft and satellite-to-ground transmission links. Further work would be required,

however, to establish whether scintillations

would occur if SPS heated the upper ionosphere. Presently, the theoretical scaling

models that would extrapolate these results to

SPS conditions in the F-region are very uncerIOEnvironmental Assessment for the Satellite Power System –

Concept Development and Evaluation Program – Effects of ionospheric Heating on Telecommunications, DOE/NASA report No

DO E/ ER-10003-Tl , August 1980

1‘W E Gordon and L M Duncan, “Reviews of Space S C Ience — SPS Impacts on the Upper Atmosphere, ” Astronautics and

Aeronautics, VOI 18, No 7,8, July/August 1980, p 46

‘

2S Basu, A L, Johnson, J A Klobuchar, and C M Rush, “Preliminary Results of Scintillation Measurements Associated With

Ionosphere Heating and Possible Implications for the Solar

Power Satellite, ” Ceophysica/ Research Letters, VOI 7, No 8,

August 1980, pp 609-612

tain. In order to test these theories, the groundbased heating facilities will have to be upgraded

In sum, it appears that effects on telecommunications in the lower ionosphere would

probably be negligible, but more study of the

upper ionosphere effects is needed. By making

the heating facilities more powerful, the following research can be conducted:

●

●

Lower ionosphere: verify scaling theory;

and test additional telecommunication

systems (e. g., VHF, UHF, satellite-toground)

Upper ionosphere: refine and verify Fregion scaling laws and ionospheric physics and then test effects on representative

telecommunications systems for SPS

equivalent heating.

Lasers

The most significant potential environmental effects associated with the SPS laser system

appear to be local meteorological changes and

beam spreading due to tropospheric heating.

Tropospheric heating would result from

energy absorption by aerosols and molecules

and from the dissipation of receptor waste

heat. Attenuation by scattering from molecules and by absorption and scattering from

aerosols would be greatest for short wavelengths. Thus scattering would be only significant for visible wavelength lasers, while aerosol effects become important to infrared lasers

only under hazy or overcast conditions.

The absorption of laser energy would lead to

a process called “thermal blooming, ” in which

a density gradient acts as a gaseous lens that

83-316 0 - 81 - 13
186 ● Solar Power Satellites

can spread, distort or bend the laser beam.13

The severity of the thermal blooming would be

a function of several parameters, including the

frequency and intensity of the laser, the wind

velocity, atmospheric density, absorption and

altitude. Laser wavelengths that have high atmospheric transmittance would be less likely

to suffer from thermal blooming. Thermal

blooming could also degrade and spread the

beam. It is clear that if spreading did occur it

would be less critical for the space-to-Earth

SPS beam than for Earth-to-space transmission

(i.e., laser pilot beam) that would be deflected

earlier in its path.

Tropospheric heating would be likely to induce meteorological alterations. It is unlikely

that global climate changes could result since

the absorption of laser energy would be less

than the typical natural variations of the atmosphere; it would take the deployment of

200,000 to 400,000 laser systems before the

global climate might be affected. ” The potential local weather effects include changes in

wind patterns, evaporation of sections of

ground fogs and clouds and elevated temperatures. None of these effects are expected to exceed those associated with conventional nuclear powerplants of comparable powe r

rating. ’5 The most significant potential impact

would be updrafts above the receptor site,

which might induce cloud formations (a problem for the beam) and severe turbulence in the

lower troposphere. Increased turbulence is not

necessarily an adverse effect; the upward convective air movement would promote vertical

mixing and the dispersal of waste heat. 16 However, the turbulence could present a hazard to

aircraft that flew in the affected region. For

this and other reasons, it has been suggested

that aircraft be restricted from flying through

transmission areas. 7

The laser beam would be capable of boring

holes through thin clouds and fog by evaporat13R E Beverly, Sate//ite Power Systems (SPS) Laser Studies,

Technical Report–Laser Environmental Impact Study, VOI 1,

Rockwell International report No SSD 80-0119- 1

“Ibi d

‘Slbld

“[bid

“Ibid.

ing the water from aerosol droplets. After passing through the beam, the cloud fog would

recondense. Portions of noctilucent clouds in

the mesosphere might also be vaporized. The

possible environmental consequences, such as

alteration of the continental cloud distribution

or albedo, would be slight but research would

stiII be needed.

Preliminary analysis indicates that the potential impacts in other atmospheric regions

would be negligible. 18 In the stratosphere,

ozone would not be affected for wavelengths

greater than 1 micron. Possible perturbations

of the plasma chemistry by the laser beam in

the mesosphere and thermosphere are believed to be small and inconsequential, since

the interactions would be confined to the laser

beam volume; ionospheric heating would also

be negligible. ” However, research would be

needed in order to validate this conclusion.

In the near term, environmental studies

could concentrate on the following areas:

Ž

●

Thermal blooming — increase theoretical

understanding and refine models; investigate enhancement of thermal blooming by clouds; study transmission and thermal blooming as a function of laser frequency, time of year, and receptor altitude and location.

Induced clouds–study the extent and

consequences of induced clouding.

Reflected Light

The mirror system would reflect about 0.8

kW/ m

2 of light to Earth, somewhat less than

the illumination due to the Sun. 20 The primary

atmospheric effect of this additional light

would be tropospheric heating. Coupled with

the sensible heat release at the energy conversion site, the weather might be measurably

modified as convection, cloud formation, and

—— .—

‘“t Li Wa Ibrlclge, La$er %te//lte f>ower ~y$tem~, Argonne Nat Iona I I aboi-atory, AN L E S-92, January 1980

‘“llt’k erly, op clt

“K W’ BI I I man, W P G Ilbreatll, and S W Bowen, “ Sola r

I nergy 1 c onornlcs Orbltlng Reflector~ tor World Energy, ” In

I+o;t h’1~ ,]nd $tI// Beautlfu/ A4acro-Fngineerlng Revisited, F P

Davidson, et al (eds ) (Boulder, Colo American A$soclatlon for

I he A(ivancement of Science, We>tvlew Pre\$, 1980), PP 2~3-3 J9
Ch. 8—Environment and Health ● 187

rainfall above the site are increased. While no

assessment has been made of the magnitude or

consequences of this potential impact, the

weather effects of other “heat islands” of the

same scale, such as New York City that releases about 0.6 kW/m2 of heat, can be used

for comparison. ” Weather impacts on a global

scale are not anticipated since the mirror

system would add less than 0.015 percent to

the normal solar heat input. 22 Large-scale computations on weather models applicable to the

mirror system size are needed to quantify the

effects for different locations. Additionally,

the heating effects of the orbiting refiector

system could be simulated on the ground,

using solar heated ponds or other means

without the need for a demonstration satellite

and hence at a relatively low cost and at an

early time. 23

Once the potential weather impacts are

more clearly understood, the system design

and economics could be reevaluated to accommodate possible environmental concerns.

For example, one might redesign the system to

reflect less Iight to Earth or use heat dispersion

devices on the ground and in space to reject

the heat into areas that would have the minimal impact. Dichroic mirrors in space for example, could selectively reflect to Earth only

those wavelength bands that would be converted with highest efficiency at the receiving

site. It may also be found that the weather

modification induced by the mirror system

heat is actually beneficial to the receiving region by preventing cloud impingement over

site.

In addition to tropospheric heating, other

possible environmental impacts have been

suggested. The mirror system beam might perturb the photochemistry of the atmosphere,

particularly the ozone layer. However, preliminary analysis indicates that the effect

would be negligible. 24 Further study is needed

to confirm this finding and to investigate the

‘ 1 Kenneth f31 I I man, E PR 1, Private ( ommun I( atlon

“K BII I man, W P G Ilbreath, S W Howen, “Solar t ner,gy Revlslted W Ith Orbit Ing Ref Iector$, N A 5A, A me\

‘‘f311 I man, private commun Icatlon

“BII I man, G Ilbreath, and Bowen, Solar Energy F conom I( ~, ‘

Op (-It

potential photochemistry effects if dichroic

mirrors were used in space. 25

More detailed study is required before reasonable comparisons can be made between

the mirror system and the other SPS technical

options. Research priorities include:

●

●

●

weather modeling and large-scale computations applicable to large mirror system size,

the effects of dichroic mirrors on the system’s environmental impacts, and

possible ground-based experiments to

simulate mirror system heating.

Space Vehicle Effects*

There are two major environmental effects

associated with the space transportation segment of SPS: the injection of rocket exhaust

products into the atmosphere (see fig. 32) and

noise generated at the launch site (see Health

and Ecology). The severity of these impacts

would depend on the size and frequency of

launches, as well as the composition of rocket

fuels and fIight trajectory.

Assessment of the potential SPS effects on

the atmosphere is hampered by the unprecedented scale of SPS transportation requirements as well as an incomplete understanding

of the atmosphere. The reference design, for

example, requires that a heavy lift launch vehicle (HLLV), five times larger than the Saturn V,

be flown one to two times per day for 30

years.”) The other reference system space vehicles and launch schedules are shown in tables

31 and 32.

The effects of SPS exhaust products on the

atmosphere are also uncertain because much

of our theory and experience with the effects

of launch effluents stem from the space shuttle, which uses solid-fuel boosters. Since the

SPS HLLV would be fueled with liquid propellants, the composition and distribution of the

- ‘ 1+1 I In)(i n, private ( ommu n 1( at Ion

J(’t’ ,1 1)1) [ ) tor (l(~ta I Is

‘ / II L ~r(]nm(~n(,]/ ! >~c~~ment for the $ate//Itc Power ‘iy~tem

( ( )n( f>p( 1 )fII f]/oprrrcnt ,] nc] F ~ .I /[Ia (Ion Prcj#r,]m, [JOE E R-()()()!),

A[lgu\t 1‘)80
188 ● Solar Power Satellites

Figure 32.—Summary of SPS Atmospheric Effects

LEO to GEO

Orbit transfer

people carrier> chemicals

cargo carrier > ions

Alteration of

satellite environment

Alteration of plasmaspheric

and magnetospheric

populations and dynamics

Ionospheric depletion

o

SOURCE: Environmental Assessment for the Satellite Power System Concept

Development and Evaluation Program, DOEI/R-0069, August 1980.

reference system launch effluents would differ

from that of the shuttle.

The major space vehicle impacts of the reference system are identified in table 33. Presently, the greatest uncertainties are associated

with four potential effects27 (treated in more

detail in app. D):

● I n the magnetosphere, the emission of

ions from COTVS and POTVS would substantially increase the ambient concentrations of these particles. Because of our

poor understanding of the complex dynamics and composition of this region,

potential impacts can be identified, but

the likelihood and severity of these effects are highly uncertain. Possible effects

include enhancement of Van AlIen belt radiation and changes in magnetospheric

and plasm aspheric dynamics that could

perturb ionospheric electricity, tropospheric weather, and satellite

cat ions.

—— —

‘Pro~r,]m As~e\\ment Report, $tatement o

communi -

F~ndin,q\, op clt

Table 31 .—SPS Space Transportation Vehicles

Launches b Operating Main exhaust

Name Function Propellants per year altitude (km) products c

Heavy-lift Transport CH4

/O2 (stage 1) 375 0-57 C 02

, H20

launch vehicle material H2

/02 (stage 2) 375 57-120 H20, H2

(HLLV) between Earth H2

/O2 (circular- 375 450-500 H20, H2

and LEO ization/deorbit)

Personnel Transport Details not 30 0-500 C2

, H20, H2

launch vehicle personnel available

(PLV) between Earth (probably same

and LEO as HLLV)

Cargo orbit- Transport Argon

transfer vehicle materials H 2

/ 02

(COTV) between LEO

and GEO

Personnel orbit- Transport H 2

/ 02

transfer vehicle personnel

(POTV) between LEO

and GEO

30

12

500-35,800

500-35,800

Ar+ plasma

H2O, H2

H2O, H2

%HJOZ: liquid methanelliquid oxygen HJOZ: liquid hydrogenlliquid oxygen.

.

bAssuming construction of two (silicon option) 5-Gw satelliteslyear.

CCOZ: carbon dioxide HzO: water H,: hydrogen Ar + : argon ion.

SOURCE: Environmental Assessment for the Satellite Power System Concept Development and Evaluation Program, DOE/ER-0069, August 1980,
Ch. 8—Environment and Health Ž 189

Table 32.—Exhaust Products of SPS Space Transportation Vehiclesa

Altitude

Atmospheric range

region (km) Source b

Troposphere 0-0.5

0.5-13

Stratosphere 13-50

Mesosphere 50-80

Thermosphere 80-125

LEOd

LEO

Exosphere GEOd

477-GE0

HLLV, PLV

HLLV, PLV

HLLV, PLV

HLLV, PLV

HLLV, PLV

HLLV, PLV

POTV

POTV

COTVe

Total

mass

(t)c

650-

2850

3027

758

2031

33

460

153

985

Mass of specific emission products (t)

C0 2 co H 2 O H2 Ar +

260 117 260 13 —

1140 513 1140 57 —

1210 546 1210 61 —

199 90 450 19 —

— — 1960 71 —

— . 443 1 —

— — 443 11 —

— — 147 6 —

— — 0 0 985f

aMass emissions per flight.

bpLV emissions would be ~hemi~all~ similar t. those of the l+LLV, but are not Otherwise determined at ttlls time. The numbers shown are emissions Of the HLLV OIIiy

ct = metric ton = 1000 ‘g.

dLow earth orbit (LEO) is at 477 km; geosynchronous earth orbit (GEO) is at 35,800 km

eln addition t. mass emissions, the argon plasma en~lnes of the COTV would inject a significant amount of energy into this altitude range. Also ar90tl pla.slllael19illeS

would be used for satellite attitude control and stationkeeping control at GEO; these em Isslons are unknown at present and have not been included.

fAr+ mass for the silicon Photovoltalc cell option For the gallium aluminum arsenide Opt!on, the Ar+ mass Would be 212 t.

SOURCE: Environmental Assessment for the Satell)te Power System Concept Development and Evaluation Program, DOEIER-0069, August 1980.

Table 33.—Space Vehicle Impacts

Troposphere

● Ground cloud nuclei and heat could have a measurable

effect on weather

● N OX emissions are small compared to typical powerplant,

but in conjunction with ambient concentration could exceed projected EPA standards

Stratosphere and Mesosphere

● 

aEmission of water vapor may cause noctilucent clouds

in the mesosphere; climatic effects would probably be

small, but uncertain

. 

aWater and N OX are not expected to significantly alter

ozone, but uncertainties remain

Ionosphere

●

●

●

a

Formation of large ionospheric hole in F-region from

water and other effluents should not adversely affect HF

telecommunication signals over distances significantly

larger than the ionospheric depletion, impacts on other

telecommunications systems are not known; more

studies are needed; long-term depletion around launch

trajectory possible

aD&E region effects are poorly understood; impacts on

telecommunications from depletion of the ionosphere

are possible

Possibility of enhanced airglow and Perturbation of Van

Allen belts, but likelihood is-unknown’

Thermosphere and Exosphere

● 

a

Large increase in water content might alter the natural

hydrogen cycle and affect the dynamics of the region

Plasmasphere and Magnetosphere

● 

aArgon ions and hydrogen atoms might enhance Van

Allen belt radiation, generate ionospheric electric currents that would interfere with public utilities, modify

auroral response to solar activity and affect weather and

satellite communications, but probability and severity are

unknown

● The effects of the satellite structures are thought to be

negligible or easily remedied

aResearch priorities.

SOURCE: Office of Technology Assessment

●

●

●

The injection of water vapor in the upper

atmosphere would significantly increase

the water content relative to natural levels. One possible consequence is an increase in the upward flux of hydrogen

atoms through the thermosphere. If an

accumulation of hydrogen results, the

dynamics of the thermosphere and exosphere could be affected. Satellite drag

could also be increased. Models of the

natural hydrogen cycle are needed to

quantify and simulate the effects of SPS

on global scale.

The injection of rocket exhaust, particularly water vapor, into the ionosphere

could lead to the depletion of large areas

of the ionosphere. These “ionospheric

holes” could degrade telecommunication

systems. While the uncertainties are

greatest for the lower ionosphere, experiments are needed to test more adequately telecommunications impacts and

to improve the theoretical understanding

of chemical-eIectricaI interact ions

throughout the ionosphere.

Another consequence of increasing the

concentration of water in the upper atmosphere might be the formation of noctilucent clouds in the mesosphere. While

global climatic effects of these clouds are

thought unlikely, uncertainties remain,

especially with respect to the persistence
790 ● Solar Power Satellites

of the clouds as a function of temperature.

The transportation system for other SPS options could be substantially different from that

for the reference system. For example, the mirror system and the bulk of the laser system

satellites operate in low-Earth orbit (LEO). The

magnetospheric effects associated with transporting materials to geostationary orbit (CEO)

would therefore not be a problem for these

systems. Environmental impacts are also determined by the frequency of launches, which

depends on the size of the vehicle, and the

total mass in orbit. For the same size launch

vehicle and total system power, it appears that

the mirror system, which is the least massive

per kilowatt of the four alternatives, would require the least number of flights, whereas the

laser system would require the most.

Other transportation scenarios have been

proposed (see ch. 5). With respect to the

reference system, some of the environmental

effects could be mitigated by changing the

flight trajectory of the HLLV, the rocket fuel of

the COTV or other transportation characteristics that present a problem. Laser propulsion,

for example, has been suggested as an option.

The tradeoffs associated with these design

changes would need to be studied as the SPS

concept evolved.

As an alternative to the HLLV, it has been

argued that economies of scale result from

increasing the number and frequency of

launches of a vehicle much smaller than the

proposed HLLV. 28 However, it is not clear how

the effects of more launches of a smaller

rocket compare to the impacts of fewer flights

of a larger one.

A very different approach in the construction of SPS wouId be the utilization of nonterrestrial materials. This could significantly

reduce the amount of terrestrial materials that

need to be transported to space, and hence

reduce the environmental impacts associated

with the frequent launch of transport vehi-

‘“D L Aklns, “Optlmlzation of Space Manufacturing Sy$-

terns, ” In Space Manufacturing From Non- Terre\ trla/ Materla/\, J

Grey and C Krop (eds ) (New York Al AA, November 1979)

cles. 29 While the economics and technical

feasibility of this concept have been evaluated, the possible environmental impacts

have not been studied and require consideration

Electromagnetic Interference

Each SPS transmission option, whether

microwave, laser, or mirror, has the potential

for affecting other users of the electromagnetic spectrum. In general, where such effects occur they will be detrimental to one user

or another, since most systems now depend on

the relative purity of the wavelength band they

use.

Sharing the same air or ground space is possible by operating at different frequencies and

at specified power levels. This is most obvious

for radio frequencies, where the frequency

band width and power levels at which systems

can operate are assigned by national agencies

working in accord with national and international standards. Where potential for interference occurs in the radio frequency spectrum, the power level and antenna characteristics of such interference are strictly regulated

in order to keep it below the available technology’s ability to filter out undesirable effects.

The principle is to assure that electronic systems are compatible with one another, i.e.,

that interference from one system does not

degrade the overall performance of a second.

Because of the large amounts of power that

the microwave, laser, or mirror SPS systems

transmit through the atmosphere, and the extensive area covered by a full satellite deployment, potential interference effects would

be much greater than any other system which

now use the electromagnetic spectrum. They

would also be commensurately more difficult

to ameliorate. Affected parties would include

users of space and terrestrial communications

and sensor systems, radar systems, various terrestrial control devices, computers, radar and

radio telescopes, optical telescopes, and

.

‘‘J (irev, $ate//lte Power $y~tem rechrrlca/ Optlons and Econon)l{ \ c ontractor report prepared for OTA, Nov 14, 1979
Ch. 8—Environment and Health ● 191

microprocessors. SPS systems using microwaves for power transmission would generate

the greatest potential interference because

communications systems and passive receivers

of alI sorts share this portion of the spectrum,

as well as other electronic equipment (e. g.,

computers, control devices, sensors) that are

susceptible to microwave energy. The reference system is designed to transmit at 2.45

GHz, the center of the Industrial, Scientific,

and Medical band (ISM).

This analysis focuses on the affected users

on an area-by-area basis. It is based on the

presumed characteristics of the three transmission options of table 34. However, it should be

emphasized, that the precise characteristics of

the transmission beams are as uncertain as

other details of the proposed alternative systems. Not only are the characteristics of the

systems and their components poorly known,

the theory is inadequate to extend known data

to other frequencies, angles, or distances.

Nevertheless, it is possible in most cases to indicate broadly the sources of potential interference and their effects on other users of

the spectrum.

Potential Affected Users of

the Electromagnetic Spectrum

SPACE COMMUNICATIONS

All artificial Earth satellites use some portion of the electromagnetic spectrum, either

for communication, remote-sensing or telemetering data. All would be affected in some

way by the SPS.

● Geostationary satellites. These would be

most strongly affected by the microwave systems. They would experience microwave interference from the fundamental SPS frequency

(e.g., 2.45 GHz for the reference design) and

noise side bands, spurious emissions in nearby

bands, harmonics of the fundamental SPS frequency, and from so-called intermodulation

products. All radio frequency transmitters generate harmonics and minor spurious components in addition to the desired signals. The

unintentional outputs are fiItered to satisfy national and international regulations about

compatibility with other spectrum users.

Receivers also generally include sufficient filtering to prevent degradation by the residual

undesired signals. However, the magnitude of

the power level at the central frequency and in

harmonic frequencies for a microwave SPS

would be so great that the possibility of degrading the performance of CEO and LEO satellite receivers is significant. Examples of serious interference include the 2.50 to 2.69 GHz

direct broadcast satellite band, the 7.3 to 7.45

GHz space-Earth government frequency slot,’”

and the S-band National Aeronautics and

Space Administration (NASA) space communications channel.

I n addition to the direct effects from microwave power transmissions, geostationary communications satellites may experience “multipath interference” from geostationary power

satelIites due to the latter’s sheer size. I n some

cases, microwave signals traveling in a straight

Iine between two communications satellites

wouId experience interference from the same

signal reflected from the surface of the power

satelIite lying between them. Communications

satelIite uplink channels would be degraded by

multi path interference from the SPS vehicle

during orbit periods when the SPS is at a lower

aItitude than the adjacent communications

satelIites.

These adverse effects would necessitate a

limit on the spacing that a geostationary satellite must have from a power satellite in order

to operate effectively. The minimum necessary

spacing would depend directly on the physical

design of the satellite, the wavelength at which

it operates, the type of transmission device

used (i.e., klystron, magnetron, solid-state

device), and the satellite antenna sidelobe

magnitudes, transmitted power, orbit perturbations, and intermodulation product frequency

distribution and amplitudes.

Because a microwave SPS as currently configured must share the geostationary orbit with

other satellites, the value of the minimum

“’John R Juroshek, “The SPS Interference Problem – Electronic S} ~tem Effects and Mltlgatlon Techniques, ” The Final f’roceedlng~ ot the 5olar Power Satellite Program Review, Con f

800491 f[lOE), pp 411-438
192 ● Solar Power Satellites

Table 34.—Summary of Electromagnetic Effects

System Spectral region Affected systems Mechanism/effect

Microwave

Microwave

● Power radiation at central

frequency (2.45 GHz or some

other choice)

Laser

Mirrors

● Harmonics of central frequency

● Spurious noise near central

● M u I i path interference

Infrared

● Thermal radiation from

all satellite components

All wavelengths

(reflected sunlight)

● Diffuse reflections

● Specular reflections

Ž Glints

Microwave

● No discernible effect

 Infrared

● Central beam radiation

. Thermal radiation from all

components

All wavelengths

(reflected sun/ight)

● Diffuse reflections

● Glints

Microwave

● No discernible effect

Infrared

● Thermal radiation from all

components

All wavelengths

(reflected radiation)

●

●

●

Specular reflection to

terrestrial station

Diffuse reflection

Glints from structural

components

Terrestrial

LEO satellites

Radio astonomy receivers

Deep space communications

GEO satellites

Radio astonomy receivers

GEO satellites

Radio astronomy receivers

GEO satellites

Radio astronomy receivers

Infrared astronomy receivers

Optical telescopes

None

Infrared receivers near

terrestrial receiver

Radio astonomy receivers

Scatter in atmosphere, from

rectenna

Pass through SPS beams

Scatter from rectennas,

atmosphere

Direct interference

Direct interference

Direct interference

Direct interference

Scatter from rectennas

Two-beam interference

Direct interference (raised

background). Satellite

appears as spurious source

Satellite appears as

spurious source

Sky background increased.

Portions of sky obscured.

Direct interference (raised

background). Satellite

appears as spurious source

Optical telescopes

Probably no effect

None

Radio astronomy receivers Direct interference (raised

background). Satellite

as spurious source

Optical telescopes near General sky brightening

terrestrial station

Optical astronomy Sky background obscured

around satellite

Effect probably small

SOURCE: Office of Technology Assessment

necessary spacing has emerged as one of the rameters that are needed in order to calculate

most critical issues facing a geostationary SPS. the minimum required spacing. In addition,

However, in the absence of a specific design, it even if the design parameters were known acis impossible to characterize the exact form curately, the theory of phased arrays is insuffiand nature of the potential interference pa- ciently developed at present to predict the
Ch. 8—Environment and Health ● 193

minimum spacing with any accuracy. Estimates range from 1⁄20 to 10

. 

31 The lower Iimit

would probably be acceptable. However, a

minimum spacing much greater than 10 would,

result in too few available geostationary slots

to allow both types of users to share the orbit

over the continental United States.

In 1980, some 80 civilian satellites shared

the geostationary orbit worldwide, and by 1990

that number is expected to increase substantially. Even though improvements in technology will lead to a reduction in the total number

of satellites necessary to carry the same

volume of telecommunications services, total

service demand is expected to rise dramatically. At present the minimum spacing for

domestic geostationary satellites is 40 in the

6/4 GHz communication band and 30 in the

14/12 GHz band. At these spacings, a total of

90 6/4 GHz band satellites and 120 14/12 GHz

band satellites could theoretically coexist at

geostationary altitudes, in the absence of SPS.

Additional satellites could use other frequency

bands without interfering with the above satellites, though this would ultimately be limited

by the station-keeping capability of the various satelIites. Multiple use platforms represent

one possible option to reduce contention over

orbital spaces.

The laser and mirror systems in LEO would

not interfere substantially with geostationary

satellites. Even in the unlikely event that such

a satellite were to pass precisely between a

geostationary satellite and its ground station,

the time of passage as well as the apparent size

of the occluding power satellite would be so

small as to cause only a slight diminution of

the signal.

● Other satellites. In addition to geostationary

satellites that would operate at the same

altitude as the GEO SPS, there are numerous

remote sensing, communications, and navigation satellites in various LEOs that may

pass through an SPS microwave beam. Proposed high-Earth orbit (HEO) satellites

would also be affected because of shad-

‘1 E Morrison, et al , SPS Effect$ on L[ ~) and GE() Sate//ite$,

NTIA publication (In pres$)

owing in the path from orbit to terrestrial

station by the large SPS vehicles, and

receiver interference thresholds that could

be exceeded by the unintentional emissions

from the SPS platforms. They use a range of

optical and microwave sensors, particle

detectors, computers, and communication

devices. Although the optical sensors are not

damaged by a microwave beam, increased

device noise can result in microwave interference in related parts of the satellite. ” A

number of shielding and filtering techniques

are available to ameliorate potential interference. These would need to be tested for

specific satellite and deployment scenarios.

Such satellites could protect their uplink

communications receivers from adverse interference by shutting down for that short

period (a few seconds) during SPS power

beam traversal, or it might be feasible for

the SPS to shut down for the satellite

passage. ” For short-term SPS shutdown,

high-capacity battery storage would have to

be Included in the ground segment (see ch. 9,

sec B). This shutdown presents a severe control problem (reduce power, start up again),

as well as serious network load transfer complexities. It may also be possible for some

satellites to fly orbits that would not intersect the SPS beam. For example, satellites

traveling in an equatorial orbit at altitudes

lower than 1,000 km would not intersect SPS

beams directed to rectennas at 350 latitude

or greater. Computer and processing/control

circuit functions can be protected by improved module shielding and interconnection noise filtering.

The laser and mirror systems might interfere

with nongeostationary satellites by causing

reflected sunlight to blind their optical sensors

or by occluding communications beams. Of

the two systems, the mirror system would be

“W H Grant, E 1 Morrison, J r , and K C Davis, “The EMC

Impa[ t of SPS Operations on I.ow Earth Orbit Satellites, ” The

I inal Pro( eeding~ of the Solar Power Satellite Program Review,

Conf -80(M91 (DOF ), pp 411-434

‘‘P K ( hapman, “ E ncounter$ Between SPS Power Beams and

Satel Iitei In 1 ower Orbits, ” [he F\na/ Proceedings of the Solar

Power \,]te//lte Program Review, Conf -&100491 (DC) E), p p

4284 W
794 ● Solar Power Satellites

most problematic because of the large size of

the mirrors and their orbital speed. To date, no

one has calcuIated the possible adverse effects

due to this cause.

● Deep space communications. Because deep

space probes generally travel in the plane of

the solar system (known as the ecliptic), they

would be especially affected by a geostationary microwave SPS. As seen from the

Earth, the ecliptic crosses the Equator in two

places. A microwave SPS would effectively

prevent ground communication with the

probe when the latter happens to lie near the

part of the ecliptic that crosses the Equator.

This interference is especially serious for

deep space vehicles because it is essential to

be able to communicate with them at any

time for the purposes of orbit control and

for timely retrieval of stored data. The

susceptibility problem is more serious than

normal satellite communications links because of receiver sensitivities and the low

signal-noise ratios imposed by the long

distances from Earth station to probe.

It would be possible to avoid such interference by establishing a communications

base for deep space probes in orbit. As we

penetrate deeper into space, this may be advisable for other reasons. Such a communications station would effectively add to the cost

of the SPS.

TERRESTRIAL TELECOMMUNICATIONS

AND ELECTRONICS

Both civilian and military terrestrial telecommunications and electronic equipment

wouId suffer from a number of possible effects

of a microwave beam. Direct interference can

occur from the central frequency and harmonic emissions. In addition, scattered and

reflected radiation from the rectenna and

structure intermoduIation products could

cause additional interference problems for terrestrial receivers. At the very least, rectennas

would have to be located far enough from critical sites such as airports, nuclear powerplants,

and miIitary bases to render potential interference as small as possible. In addition, most

equipment would have to be modified to permit far better rejection of unwanted signals

than is now necessary. This appears to be technically feasible; primary concerns would be

modifications to the shielding of sensitive circuitry. The initial estimate of the cost of modifying terrestrial electronic equipment is in the

range of 0.1 to 5 percent of the unit cost (approximately $130 million for the 1980 estimate

of the inventory of susceptible equipment).

The EMC evaluation program determined

that most terrestrial electronic equipment

would be unacceptably degraded by SPS interference for power levels possible within a 50-

to 75-km distance of a rectenna site. The most

sensitive equipment, such as high capacity

satellite terminals and radio astronomy receivers would be adversely affected at distances of 100 to 200 km.

Mitigation techniques have been evaluated

for radars, computers and processors, sensors,

and muItichannel terrestrial microwave communications. With the exception of the most

sensitive receivers, modifying shielding and

grounding procedures and using rejection

filters in radar and communications receivers

would allow most systems to operate with the

SPS interference levels expected at the rectenna site boundary. Special mitigation techniques for more sensitive systems involving interference cancellation methods have been

considered, but they must be tested to determine the range of protection possible.

EFFECT ON TERRESTRIAL ASTRONOMY

AND AERONOMY

None of the proposed SPS systems could

benefit astronomical research except insofar

as they would indirectly provide a transportation system for placing large astronomical facilities in space. Their detrimental

effects would vary depending on the system

chosen. The impacts of a microwave system

would likely be severe for both optical and

‘1 Morrl\on, “SPS Susceptible Systems Cost Factors – lnvest111 ent 5 u (m m a ry and M It I gat Ion Cost I nc rernent E st I ma tes, ” I n

l)res~

‘P A t kstron and C M Stokes, “Work$hop on Satellit e

I)ower ~y~tem~ (SPS) Effects on Optical and Radio Astronomy, ”

( ont 7’)05141 (DOE)
Ch. 8—Environment and Health • 195

radio astronomy. An infrared laser system36

would have fewer detrimental effects on both

forms of astronomy than the reference system.

The mirror system would have its most serious

effect on optical astronomy.

● Optical astronorny. For the reference system, diffuse reflections from the satellite

structures would cause the greatest degradation for terrestrial telescopes. Because

they appear to remain stationary along the

celestial Equator, reflected Iight from a system of 15 to 60 satellites would meld together to block observation of faint objects

over a large portion of the sky near the

Equator for telescopes located between the

longitude limits of the satellites. Some

major foreign, as well as most domestic observatories would be affected. Observations

of bright objects would be possible, but degraded in quality. In addition, reflected light

from the LEO construction base could be expected to interfere with observations of

faint sources in its vicinity. Telescopes in

orbit, such as the U.S. Space Telescope, to

be launched in 1984, will travel in nonequatorial orbits and therefore would not be

affected significantly by a reference system

SPS. The danger of pointing directly at a

geostationary satellite will increase the complexity of the telescope-pointing mechanism. Astronomical photometry and spectrometry instrumentation, and high resolution telescope tracking systems would be

degraded if located within 50 to 60 km of a

rectenna site. The EMC evaluation program

indicated the necessity of improving sensor

and sensitive circuit shielding, and maintaining a minimum separation distance of 50

to 60 km between rectenna sites and telescopes using sensitive electronics to remove

SPS induced degradation.

The effect of diffuse reflections from a

laser SPS in LEO could be expected to cause

fewer problems for observations of diffuse

objects near the Equator because the laser

collection and transmission satellite would

be constantly in motion. Thus, no part of the

‘“C Baln, Potential of Law for 5P$ Power rran$ml$~lon, SPS

CDEP, October 1978

sky would be permanently blocked from

view. The relay satellites located in CEO

would not be Iikely to interfere with optical

observations. However, large moving satellites would present optical astronomy with

another observational obstacle. Scattered

light from them would vary in intensity as

the satellite passes near a celestial object of

interest, making calibration of the nearby

background radiation very difficult if not

impossible. Photographic exposures of faint

celestial objects may last from 1 to 3 hours

and individual photographs cannot be

added effectively. The laser satellite would

interfere with infrared astronomy studies involving wavelengths adjacent to the transmission wavelength of the beam.

The mirror system, which would involve a

number of large, highly reflective moving

mirrors in LEO, wouId have very serious

effects on optical astronomy. While the precise effect has not been calculated, it would

render a large area around the ground stations totally unacceptable for telescopic

viewing. Because of diffuse reflections from

the atmospheric dust and aerosols above the

ground station, the individual mirrors would

create moving patches of diffuse light that

would preclude studies of faint objects that

lie in the direction of the satellite paths.

Radio astronomy. Radio astronomy would

suffer two major adverse affects from microwave systems: 1) electromagnetic interference from the main PS beam, from harmonics, from scattered or reflected SPS signals,

and from reradiated energy from rectennas;

and 2) increasing the effective temperature

of sky noise background, which has the effect of lowering the signal-to-noise ratio of

the radio receivers. Studies of faint radio objects near the Equator would be rendered

impossible. In addition, rectennas would

have to be located more than 200 km from

radio observatories and in terrain that would

shield the observatories from reradiated

microwave energy. Also of concern to radio

astronomers is the possibility that expected

failures of the klystron or other microwave

emitting devices would resuIt in spurious

noise signals that would further disrupt

radio astronomy reception.
196 ● Solar Power Satellites

Neither the laser nor the mirror systems

would contribute to the first effect. However,

they would raise the effective temperature of

the sky background. Low-level measurements

such as scientists now routinely conduct, for

example, to measure the amount of background radiation from the primordial explosion of the universe would thus be extremely

difficult if not impossible from terrestrial stations. Many other types of sensitive radio

astronomy observations would be seriously

degraded.

The susceptibility of radio astronomy receivers results from their high sensitivity, and

the wide range of observing frequencies in the

microwave spectral region. Mitigation techniques effective for other electronic equipment are only marginally useful because of the

sensitivity factor and associated dynamic

range. A preliminary review of interference

canceling techniques indicates that thi s

method has a high probabiIity of providing rejection of SPS signals to a level that would

allow rectenna sites to be located within a 100-

to 150-km range from radio astronomy facilities. Detailed design and testing at a radio

astronomy receiver is necessary because of the

unique aspects of integrating a canceler function into such complicated and sensitive

receivers.

Space basing of radio telescopes, especially

on the far side of the Moon, would eliminate

the impact of SPS and other terrestrial sources

of electromagnetic interference. However,

such proposals, though attractive from the

standpoint of potential interference, are unlikely to be attractive to astronomers for many

decades because of their high cost and relative

inaccessibility.

● Optical aeronomy. Much of our knowledge

of the upper atmosphere is gained by nighttime observations of faint, diffuse light.

Some of the observations that are made today must be carried out in the dark of the

Moon. The presence of satellites whose integrated brightness is equal to a quarter

Moon would effectively end some studies of

the faint airglow and aurora. Other observations would be severely limited in scope.

Terrestrial Activities

The terrestrial environment would be affected by SPS in a number of ways. The construction and operation of receivers could

alter local weather, land use, and air and water

quality. The mining, manufacturing, and transportation associated with SPS could also

adversely affect the environment.37

Land Use and Receiver Siting

Land use and receiver siting are important

issues for SPS, especially from a political

perspective (see ch. 9, Issues Arising in the

Public Arena).* This is due in part to the

microwave and mirror system land requirements for large contiguous areas for receiving

stations and transmission lines. In siting

receivers, tradeoffs wouId have to be made between a number of parameters such as the topography and meteorology of the candidate

locations, local population density, land and

transmission line costs, electromagnetic interference, and electricity demand, as well as

environmental impacts. The construction and

operation of SPS receivers wouId have measurable effects on the ecology, soil, air and water

quality, and weather of the receiver area. 3 8

Since many of these impacts are site-specific,

an extensive program wouId have to be carried

out in order to locate and assess each proposed site.

The severity and extent of the environmental impacts of SPS ground receivers and transmission lines would also depend on which SPS

system is deployed. For example, as shown in

table 7, the baseline mirror system (1) would

deliver power to a few, extremely large sites,

whereas the laser system might be designed to

“5ate//lte Power System, Concept t3evelopment and Eva/uatlon Program, reference system report, DOE/E R-0023, October

1978

‘The majority of remarks made In this section pertain to landbased receiver sites as specif]ed by the technical systems adciressed In this report It IS Important to note, however that off-

~hore receptor sltlng that may alleviate some of the problems

,) ~soc Iated with land-based s Ites IS a I so possible

‘“ fnbjronmental Assessment for the Satelllte Power System

( oncepf lleve/opment and Eva/uatJon Program, DOE’E R-0069,

Augu~t 1980
Ch. 8—Environment and Health ● 197

generate the same amount of power at a great

number of sites, each of which is two to three

orders of magnitude smaller than the mirror

sites. Smaller mirror system (1 1) sites are also

possible.

For safety purposes, buffer zones would be

established around each site. For the laser

design, the infrared power density at the edge

of this zone would be 10 mW/cm2 (see fig. 33).

As shown in figure 34, the microwave power

density at the edge of the reference system exclusion boundary would be 0.1 mW/cm2

. If microwave standards become considerably more

stringent, SPS land requirements could increase. For example, if the power density at

the edge could not exceed 0.01 mW/cm2 (the

Soviet standard), then each site would require

almost 1,700 km2 of land.39

In addition to land for receivers, about 20 to

850 km2 would be needed for launch facilities. 40 This could be made available through

expansion of the Kennedy Space Flight Center

Figure 34.—Microwave Power Density at Rectenna

as a Function of Distance From Boresight

2.45 GHz

50 23 mW/cm2

10

5

1.0

“J B Black burn, Power Mapping of

 for DOE/NASA Report HCP/

R-4024-10, October 1978

.01

Figure 33.— Receptor Site Protection Radius as a

Function of the Perimeter Laser Power-Density Level

10

10’

10-3 10– 2

10- ‘ 10” 10’

Perimeter power density, W/cm2

SOURCE: R. E. Beverly, Satellite Power Systems Laser 

 Report—Laser Environmental vol. 

Rockwell International report, SSD 80-0119-1.

.005

.001

o 5,000 10,000 15,000 20,000

Ground radius, m

SOURCE Satellite Power System, Concept Development and Evaluation Program, reference system report, DOE/ER-0023, October 1978.

in Florida, although environmental considerations might preclude this option. Transmission

line, mining, and transportation land uses are

not considered in table 35. More analysis is

needed to determine these impacts and to explore tradeoffs between centralized and dispersed electricity systems with respect to

transmission line siting. In table 36, the SPS reference system is compared to other electricity

powerplants.
198 ● Solar Power Satellites

Figure 35.—Rectenna/Washington, D.C. Overlay

Washington , D C

SOURCE: Office of Technology Assessment.

Some of the environmental, societal and institutional problems associated with land-use

and receiver siting might be remedied by siting

receivers in shallow offshore waters. For some

land-scarce areas such as New England and

Europe, this concept is particularly desirable.

The taper of the solid-state power-transmission

system makes offshore siting particularly attractive. A few preliminary technical studies

have been conducted,” including an offshore

rectenna siting study, 42 (see fig. 36). However,

little attention has been paid to the environmental ramifications of offshore siting. Areas

of special concern include the effects on

weather and ecosystems from thermal release

and the effects of microwaves on aquatic life

and birds that might be attracted to the

receiver

Land-use problems might also be alleviated

by innovative receiver designs that would permit multiple land use under the receivers, such

as crop agriculture, biomass production and

aquaculture.43 Again, however, until the biological effects of microwaves and reflected

sun Iight are better understood, the environmental impacts and hence viability of these

ideas are largely unknown.

.——4 J Freeman, et al , So/ar Power Sate//ite Of f$frore Rectenna

Stur/y, contract report No NAS 8-33023, prepared for Marshall

$pace Flight (-enter, May 1980

‘ ‘i]tellite Power $y\tem [5PS] Rectenna $Itlrrg A vallablllty and

Ll~~trlhurjon of Nor-n jna//y E/jglb/e Sites, DC) E/E R-10041-TI O, Novem ber 19 8 0

‘ Crey, [Jp c It

Table 35.—SPS Systems Land Use

Number of Total land area

sites for (kmz

)

SPS system k m

2

/site km2/1,000MW 300,000 MW for 300,000 MW m

2

/MW-yr a

Reference . . . . . . . . . . . 174.0 35.0 60 10,400.0 1,280

Solid statec . . . . . . . . . . . 50.0 33.0 180 9,000.0 1,230

Laser Id. . . . . . . . . . . . . . . 0.6 1.2 600 360.0 44-35e

Laser Ilf . . . . . . . . . . . . . . 40.0 80.0 600 24,000.0 2,960-3,550 e

Mirror If . . . . . . . . . . . . . . 1,000.0 7.4 - ’29 2,200.0 274-329e

For comparison

Washington. . . . . . . . . . . 174.0

New York City. . . . . . . . . 950.0

Chicago. . . . . . . . . . . . . . 518.0

a These “nlt~ are presented for ~O~ParlSOn with table 36, The values for the reference and solid-state designs assuf’rle a so-year lif@tirne and a capacity factor Of ().9.

b Rectenna at 34o latitude covers a $jkrn x lskrll (1 ITkrnt) elliptical area, Microwave power density of edge of rectenna is 1.0 mW/cm2. If an exclusion boundary iS Set at

0.1 mW/cm2, then the total land per site is approximately 174 kmz (2 km extra on each side for buffer zone). J. B. Blackburn, Sate//ire Power System (SPS) Mapping of

Exc/usion Areas for Rectenrra Sites, DOE/NASA report No. HCP/R-4024-10, October 1978, Does not include land for mining or fuel transport.

C The solid-state sandwich design is described in J Grey, safe//j~e power sys~em ~ecffr’rjca/ op~lo~s and Economics, contractor report prepared fOr OTA, NCrV, 14, 1979.

d Laser 1 and Laser 11 are two laser systems considered by DOE, Both deliver the same amount of power but the beam of Laser I iS more narrow (and hence more intenSe)

than that of Laser Il. See C. Bain, Potentia/ of Laser for SPS Power Transmission, SPS CDEP, October 1978.

e The values for the laser and mirror systems assume a 30-year lifetime and Capacity faCtOrs of 0.75-09

f Minor system parameters are defined by SOLARES System as described in K. Blllman, W P Gllbreath, S. W. Bowen, “Solar Energy Revisited With Orbiting

Reflectors,” NASA, Ames,

g The SO LARES system is designed to deliver 810 GVV to 6 sites; 2 SOLARES sites actually ~)rovlde 270 GW,
Ch. 8—Environment and Health ● 199

Table 36.—Summary of Land Requirements

Purpose Construction Plant Fue l Disposal Transmission —

CG/CC

Quantity —a 7.2-150 m2

1MW-yr

Duration —c 30 yr

Location —c —c

FBC

Quantity —a 5.2-16.8 m2

/MW-yr

Duration —c 30 yr

Location —c —c

1,800-4,520 5 m2

1MW-yr

m

2

/MW-yr

30 yr —c

—c —c

—c 1.4 m2

/MW-yr

—c —c

—c —c

300 m

2

1MW-yr

(480 km)b

30 yr

—c

300 m

2

/MW-yr

(assume same as

combined cycle)

30 yr

—c

L WR

Quantity —a 57-174 m2/MW-yr

Duration —c 30-40 yrs

(20 m2

/MW-yr

“permanent”)

Location —c —c

31 m2/MW-yr 4 m

2

/MW-yr 225-1000

m

2

/MW-yr

(480-1600 km)b

30 yr 1 06 years 30-40 yrs

—c —c —c

LMFBR

Quantity —a 76-133 m2

/MW-yr

Duration —c 30 yr

Location —c —c

5 m

2

/MW-yr —c 200 m2/MW-yr

(plant life- (80 km)b

time) and

.25 m2

/MW-yr

(permanent)

—c —c 30 yr

—c —c —c

.—

TPV

Quantity —a 600-3,800 m2

/MW-yr neg 1d

neg 1d300-3,000

(depending on cell m

2

/MW-yr

efficiency and (480-4,800 km)b

capacity factor)

Duration —c 30 yr N A

e N A

e

30 yr

Location —c Southwest NA NA —c

STE

Quantity —a 2,260-6,650 m2

/MW-yr neg1d

neg1d

300-3,000

m

2

/MW-yr

480-4,800 km)b

Duration —c 30 yr NA NA 30 yr

Location —c Southwest NA NA —c

OTEC

Quantity —a neg1 neg1dneg 1

d 300 m

2

/MW-yr

(480 km)b

Duration —c N A

e N Ae

N A e 30 yr

Location —c N A

e

NA NA —c

SPS

Quantity 20-850 km2

1,480 m21MW-yr gneg1d

neg1d300-1,000

(launch) (rectenna)f m

2

/MW-yr

(480-1,600 km)b

Duration 30 yr 30 yr N A

e NAe

30 yr

Location Florida? —c NA NA —c

approximately the Sum of plant and transmission requirements. ‘N A-Not applicable

bDist ance to load center. flncludes buffer zone, rectenna proper OcCIJpleS about 50°1. Of total.

cData lacking; some categories are discussed I n test 9Assuflles 200 krnz per rectenna site.

‘Negligible.

SOURCE: D. E. Newsom and T. D. Wolsko, Prelirnmary Cornparatwe Assessment of Land Use ~Or Satelhte Power Systems and AltemafiveE/ecmc Energy Technologies,

DOE/NASA report No. DOE/ER-0058, April 1980.
200 ● Solar Power Satellites

Figure 36.—Offshore Summary Map

I

Offshore siting study - dark areas are not eligible for rectenna siting

SOURCE: Satellite Power System of 

1OO41-TIO, November 1980.

If SPS is to be deployed on a multinational

scale, the siting constraints may be different

from those in the United States. This is especialIy true with respect to microwave exposure

standards, which in some countries are more

stringent than in the United States (see Health

and Ecology, Microwaves). The environmental

standards of other nations and their effects on

SPS siting requirements need to be explored in

more detail.

A siting study for the continental United

States has been conducted for the reference

system to determine if 60 candidate sites can

be found. ” The United States was divided into

grids, each approximately the size of a rectenna. Grid squares were eliminated from consideration if they violated a set of “absolute”

exclusion variables that included inland waters, high population density areas, marshlands, military reservations, habitats of endangered species, National recreation areas,

 B. and B A “Satellite Power System

 Siting Study, ” in Proceedings of the 

Power Program Review, Apr 22-25, 1980, DOE/NASA

report No Conf -800491, July 1980

Atomic Energy Commission lands, and unacceptable topography. Sites were also excluded

if they were found within a specified distance

from military installations, nuclear powerplants and other facilities that might suffer

from electromagnetic interference with the

SPS microwave field.

In figure 37, ineligible grids were marked

with an “x.” In this first exercise 40 percent of

the United States remained eligible. After the

application of additional “potential” exclusion variables that were categorized as having

an unknown or adverse, but potentially correctable impact (e. g., agricultural lands and

flyways of migratory waterfowl), 17 percent of

the United States remained eligible. In general,

the greatest number of eligible sites was found

in the West, Southwest, and in the northern

regions of the Midwest; the least number of eligible sites occurred in the Mid-Atlantic States,

where 3 to 10 percent of the land was eligible

(31 to 83 grids, depending on the criteria for

eligibility). The exclusion variables that had

the greatest incremental effect in rendering

land ineligible included topography, popula-
Ch. 8—Environment and Health • 201

Figure 37.—Satellite Power System—Societal Assessment

SOURCE: Satellite Power Svstem (SPS) and of Nominally Eligible Sites, DOE/ER1OO41-TIO, November 1980.

tion and electromagnetic compatibility’ (absolute variables) as well as private agricultural

lands, flyways, and Federal dedicated and protected lands (potential variables).

The siting study also revealed an important

point about the siting of smaller rectennas.

Smaller site sizes could increase the likelihood

that sites identified as eligible (in the first

application of absolute exclusion variables)

would remain so upon closer examination in a

“validation” process. However, they would be

unlikely to make previously excluded grid

squares eligible. Therefore, it was concluded

that smaller rectenna size (i. e., one-fourth or

one-half the rectenna area) would not make a

substantial difference in the siting process. 45

The effects of eliminating isolated sites were

also considered on the assumption that local

variations and the problems associated with

public or private land acquisition would make

siting more difficult in areas that did not contain a large number of adjacent eligible grid

*This was also an important constraint for the siting of offshore 

“Ibid

squares. By imposing the constraint that eligible sites had to fall within a 3 x 3 grid pattern,

the amount of eligible sites dropped dramatically, especialIy in the Mid-Atlantic region and

the Southeast. A less restrictive requirements

of 2 x 2 grid patterns produces a considerably

less drastic result.

The siting results (from the application of

“absolute variables”) were then correlated

with the distribution of projected electrical

demand. 46 Based on one projection of future

electricity demand, it was concluded that the

only potential site scarcity would occur in the

Mid-Atlantic region (see fig. 38). In most other

regions there wouId be about 100 times more

eligible grids than “required” sites. Scarcity of

large load centers relative to allocated rectennas could be a problem in sections of the Midwest and West.

A prototype environmental assessment was

conducted for a rectenna site in the California

desert (Rose Valley, 250-km north of Los

“A “Relationship of Eligible Areas to Projected 

 Demand, “ in The Final Proceedings of the Solar Power 

 Program Review, Apr 22-25, 1980, DOE/NASA report No

 -800491”, July 1980

83-316 0 - 81 - 14
202 ● Solar Power Satellites

Figure 38.—RegionaI Generation (2000) and Rectenna Allocations

18.40/o

600

Note: This is based on the EIA Leap Series C (1978) protection of electricity the year 2000 which assumes a 4 10/. 

 growth rate per year from 1977-1995. See chapter VI or discussion on alternative electricity growth rates

SOURCE. A. of Areas to Projected Elect Demand,” Proceed/rigs 

Power Satellite Program Apr 22-25, 1980, DOE/NASA No conf -800491, July 1980

Angeles).” The major environmental impacts

(excluding microwave effects) and possible

solutions are summarized in table 37.

The assessment emphasized that large

amounts of contiguous land area must be completely committed to the project, totally

displacing existing land use and completely

altering the existing natural environment. investigators also noted that after the site

boundaries are selected, there is no flexibility

in the siting of individual rectenna structures,

so that areas particularly sensitive to SPS impacts could not be avoided. To alleviate adverse effects, they recommend that land areas

 ype Environmental Assessment of the Impacts of Siting

and Constructing a Satellite Power System Ground Receiving Station DOE/NASA report No DOE/E R-O072, August

1980

much larger than the minimum requirements

be located in the site selection process. In addition, the study recommends that: 1) rectenna

panels be light and open to allow passage of

sunlight and rain; 2) natural characteristics of

the site be considered in the panel and diode/

dipole design, e.g., taking account of possible

attraction birds and rodents might have to the

panels for resting or nesting; and 3) the design

minimize the use of materials.

Finally, investigators note that the siting of

receivers in the Southwestern United States

will be especially hampered by land-use conflicts with other energy sources, archaeological

sites and military programs. In particular it is

pointed out that 15 percent of the California

Conservation Area is reserved for defense purposes.
Ch. 8—Environment and Health Ž 203

Table 37.—Summary of Environmental Impacts of Rectenna Construction and

Operation at a Specific Study Site

Technical area Rectenna construction Rectenna operation Mitigation

Air quality and climatology . Probable standards . No significant air quality ● Adequate dust suppression

violation for nitrogen impacts. program during construction

oxides, particulate, ● Unknown, but possibly would mitigate particulate

and hydrocarbons. significant microclimateic impacts.

● No climatic impacts. effects at or near ground . Extending construction

surface schedule would reduce

emission peaks for hydrocarbons and nitrogen oxides.

● Pending further research,

project modifications might

be needed for ground surface microclimate impact

Noise ● Substantially elevated . No significant impact. ●

noise levels, but in

areas with low population density,

● Possible impacts on

noise-sensitive ●

species.

Geology and soils ●

●

●

●

●

Geologic impacts less

important than

geologic constraints.

Study area very active

seismically, but within

normal range for

southern California.

Soils impacts significant: large disturbed

area, compaction,

wind/water erosion.

Soils constraints: diversity of soils types

implies variability in

engineering properties

(e.g., shrink/swell

potential, corrosivity

to metals/concrete).

Improved noise control

technology by construction

time frame for vehicles,

equipment, and processes

would mitigate impacts.

During construction, noisesensitive habitats should be

avoided to maximum extent

possible during breeding

and nesting seasons.

● Seismicity has potential . Thorough seismic and soils

for facility destruction studies required as part of

or loss of efficiency site-specific engineering.

(alinement v. satellite). ● Careful soiI-stabilization/

● Soil productivity impacted age/erosion-control

for project life: depends programs required.

on extent and degree of

construction—phase and

ongoing operations disturbance.

Hydrology and water quality ● Project requirements:

2-14 x 106 m

3

(depends on dust

suppression methods

used).

● Meeting project needs

from groundwater

would lower water

table 0.2-1.5 m/yr;

would reduce underflow to adjoining

valley, could lower

water level in nearby

lake; might contaminate usable water

through hydraulic connection with unusable

ground water.

. Project requirements minor ●

unless major revegetation

program undertaken.

Revegetation could require ●

27 x 106 m

3

/yr

for 3 yr, that could

cause water table

drawdown.

●

Careful soil stabilization/

drainage/erosioncontrol program required.

Ground water withdrawal

impacts could be

alleviated by importing

water from outside

study area.

Proper sewage control

program necessary during

construct ion to prevent

water quality degradation).
204 ● Solar Power Satellites

Table 37.—Summary of Environmental Impacts of Rectenna Construction and

Operation at a Specific Study Site-Continued

Technical area Rectenna construction Rectenna operation Mitigation

Flora ● Land disturbance ● Impacts similar to ● Reestablishment of

would completely construction phase. preexisting fIora

modify site’s ● Microclimate changes at problematic; major

floral communities. ground surface a key and difficult revegetation

● Possible indirect issue for severity program required.

impacts on flora from and potential for ● Careful placement of

hydrologic changes, mitigation of floral ancillary facilities necessary

air and water impacts. to minimize impacts

pollutants, and on sensitive habitats.

personnel activities ● Careful planning,

● No endangered design and construction/

species present operations practices

at Rose Valley/ necessary to minimize

Coso; one rare indirect impacts (e.g.,

Land disturbance ●

would completely

modify site faunal ●

communities.

Possible indirect

impacts on fauna ●

from hydrologic

changes, air and

pollutants, personnel

activities, and loss

of feeding areas

for nearby fauna.

Surface water

sources for

migratory water

and land birds

would be lost

(Playas) and

jeopardized (Little

Lake).

One protected species

(Mohave ground

squirrel) found in Rose

species present. water quality degradation).

Fauna ●

●

Impacts similar to ●

construction phase.

Impacts closely

related to fIora

impacts.

Microclimate changes

at ground surface ●

a key issue for

severity and potential

for mitigation of

fauna impacts.

●

●

Valley.

Land use ●

●

●

●

Reestablishment of

preexisting fauna

problematic; closely

linked to strategy

and success of

floral mitigation.

Careful placement of

ancillary facilities

needed to minimize

impacts on sensitive

habitats.

Careful planning,

design, construction,

O&M practices, and

construction scheduling

needed to avoid

indirect impacts

and to avoid

sensitive habitats

during breeding and

nesting seasons.

Total displacement Same as construction ●

of existing site phase

uses (e. g.,

farming grazing,

recreation).

Minor loss of

mineral resources

(cinder, pumice).

Minor indirect

(growth-related

impacts.

Potential land

acquisitior/use

conflicts with Navy

(China Lake NWC),

energy (geothermal),

wilderness,

archaeological

resources, native

American use and

access to cultural

and religious sites.

Major impacts could

not be mitigated.

It might be possible

to achieve joint

use of rectenna

sites but this

remains speculative.

SOURCE: Prototype Environmental Assessment of the Impacts of Siting and Constructing a Satellite Power System (SPS) Ground Receiving Station (GRS), DOEINASA

report No. DOE/ER-0072, August 1980.
Ch. 8—Environment and Health ● 205

Receiver Structure: Weather Modification

Other DOE studies have investigated the potential of the rectenna for modifying local

weather. They indicate that the surface roughness and albedo of the rectenna structure and

the waste heat generated by rectenna operation (750 MW per site) would have a small, but

detectable impact on regional weather and climate .

48 49 In particular, rectennas would perturb the average surface heat exchange by

about 10 percent. SPS land-use changes could

alter temperature (on the order of 10 C), cloud

density and rainfall. However, it is important

to note that these effects would be no greater

than those attributable to other nonindustrial

urban activities. For example, the waste heat

generated by typical coal and nuclear plants

range from 750 to 6,000 MW. The waste heat

rejected at laser receptor sites, would also produce weather effects that would be less signifi48 Environrnerrta/ Assessment for the Sate//ite Power System

Concept Development and Evaluation Program, op cit.

“Proceedings of the Workshop on Meteorological Effects of Satellite Power System Rectenna Operation and Related Microwave

Transmission Prob/ems, Aug 23-25, 1978, DOE/NASA report No

Conf -7808114, December 1979

cant than those associated with nuclear plants

of comparable power. 50

Resources

The construction and operation of SPS

couId strain supplies of some critical materials, as shown in table 38. The most serious

problems arise for the solar cell materials (e. g.,

gallium, gallium arsenide, sapphire, and solar

grade silicon) and the graphite fiber used for

the satellite structure and space construction

facilities of the reference system. 51 It appears

that the silicon SPS systems pose less serious

problems than the gallium arsenide option, but

this may be due to the immature state of gallium arsenide technology. The most serious resource strain for the galIium arsenide system is

gallium; for the silicon option, large amounts

of electricity might be needed to produce the

cells.

‘OBasu, Johnson, Klobuchar, and Rush, op clt

“ R R Teeter and W M jamieson, Preliminary Materia/s

Assessment for the Sate//ite Power System (SPS), DOE/NASA

report No DOE/E R-0038, January 1980

Table 38.—Summary of Materials Assessment Results

World Percent

Percent production SPS Net world

supplied as growth percent of percent resource cost

Parameter byproduct rate demand imported consumption $Ikw

Threshold valuea 

. . . . . . . . . . . . 5 0 % 1 0 % 100/0 50% 200% $50/kw

Gallium. . . . . . . . . . . . . . . . . . . . A A A —

Graphite fiber. . . . . . . . . . . . . . . —

— —

A A — A

Sapphire. . . . . . . . . . . . . . . . . . . —

—

A A — A

Silicon SEG . . . . . . . . . . . . . . . . –

—

A A — A

Gallium arsenide. . . . . . . . . . . . —

—

A A — A

Electricity. . . . . . . . . . . . . . . . . . —

—

— — — A

Arsenic/arsenic trioxide. . . . . .

—

B — — B

Kapton . . . . . . . . . . . . . . . . . . . . —

— —

B B —

Oxygen (Iiq) . . . . . . . . . . . . . . . . –

— —

B B —

Silica fiber . . . . . . . . . . . . . . . . . —

— —

B B —

Silver. . . . . . . . . . . . . . . . . . . . . .

— —

B — — B

Silver ore . . . . . . . . . . . . . . . . . . —

— —

— — B B

Glass, borosilicate . . . . . . . . . . —

—

— B — —

Hydrogen (Iiq) . . . . . . . . . . . . . . —

—

B — —

Mercury . . . . . . . . . . . . . . . . . . . —

— —

— — B

Mercury ore . . . . . . . . . . . . . . . . —

— —

— — B

Methane. . . . . . . . . . . . . . . . . . . —

— —

B — —

Petroleum. . . . . . . . . . . . . . . . . . —

— —

— — — B

Steel . . . . . . . . . . . . . . . . . . . . . . —

—

— — — B

Tungsten . . . . . . . . . . . . . . . . . . —

—

— — B — —

Note: “A” signifies problem of serious concern “B” signifies problem of possible concern.

aparameter Value above Which a potential problem exists. Materials in this table exceeded these values where an “A” or “B” is recorded.

SOURCE: R. R. Teeter and W. M. Jamieson, Prelimlrrary Materials Assessment for ttre Satellite Power System (SPS), DOEINASA report No. DOE/ER-0038, January 1980.
206 ● Solar Power Satellites

Most of the resource constraints identified

stem from limitations in production capacity

rather than exhaustion of reserves. SPS could

compete for graphite composite with the automobile industry and, depending on its time of

introduction, with terrestrial photovoltaic

technologies and the electronics industry for

semiconductor materials. The demand by SPS

for a few materials such as gallium, tungsten,

and mercury could also increase U.S. dependence on foreign sources. Further analysis

wouId be required to determine the severity of

the resource limitations identified for the

reference system and possible measures that

wouId circumvent them.

While no assessment has been made of the

material requirements for any of the other SPS

technical options, a few observations can be

made. The solar celI, graphite, and transportation materials that are problematic for the

reference design might also be used in the

three other options. The solid-state design calls

for silicon or gallium arsenide devices in the

transmitting antenna as well as in the solar collector. While the solid-state satellites would be

smaller than the reference design, the solidstate material needs per unit energy would be

greater. Therefore, if the reference design were

to strain supplies of semiconductor materials,

the solid-state variant most certainly would tax

them as well (assuming that both systems deliver the same total amount of power and use

the same materials). The laser and mirror systems would require slightly less photovoltaic

material per kilowatt of delivered electricity

than the reference system. The quality of the

photovoltaics material used in the mirror

design might be different than the reference

materials however, since in the mirror system

they would be placed on the ground. AII of the

systems would require graphite for structures,

and fuels for space transportation. Further

analysis is required in order to compare the

material requirements of the alternative

designs to the reference system. Moreover, the

effect on SPS material requirements of using

nonterrestrial materials (lunar soil contains

aluminum, titanium, iron, silicon, and oxygen)

and developing space processing and industrial capacity needs to be investigated.

Mining, Manufacturing, and Transportation

The minerals extraction, materials processing, manufacturing, and transport activities

associated with SPS could result in a measurable increase in air and water pollution and

sol id wastes. 52 For example, the potential environmental impacts of mining include water

pollution from leaching and drainage modifications, air pollution from fugitive dust and

land disturbance from strip mining, subsidence

and spoil piles. Manufacturing would produce

stack emissions, process effluents and solid

wastes. In table 39, order-of-magnitude estimates have been made of some of the environmental impacts resulting from these reference

system activities. The incremental domestic

processing of materials required for SPS can

also serve as a rough guide to increased pollution levels.

While these exercises help identify the

potential scope and extent of environmental

impacts, a thorough and quantitative assessment is presently lacking. However, it is

anticipated that most impacts would be conventional in nature and could probably be

minimized by methods currently used in industry 5‘ There is no information on similar effects

‘ /’rfj[o/ I I)(I I nvlronrrrent,]/ A >je~smerrt ot the /rrrpactj ot fi(lng

,2 n(l ( on\ [ rj 1 f t /nLJ ,] S<l tcI//l te Power \ yj tern / $ P$ / (; ro~in(/ Recel t

Ing }t,It IoII (, R ‘i/, DC) E NASA repot-t No DOE E R-()()72, Augu\t

1 ()~()

I Ibid

Table 39.—Annual Environmental Effects of SPSa

(mining, processing, manufacture,

and ground-based construction)

Air pollutants Percent U.S. totalc

Particulate . . . . . . . . . . . . . . . . . . . . . . 0.8%

Sulfur dioxide. . . . . . . . . . . . . . . . . . . . . 0.04

Carbon monoxide . . . . . . . . . . . . . . . . . 0.05

Hydrocarbons . . . . . . . . . . . . . . . . . . . . 0.05

Nitrogen dioxide . . . . . . . . . . . . . . . . . . 0.005

Nonrecoverable waterd

. . . . . . . . . . . . . . . 0.24

Solid wastee. . . . . . . . . . . . . . . . . . . . . . . 0.70

Land requirementsf. . . . . . . . . . . . . . . . . . 0.12

aBaSed on ~~ earl Ier SPS cJeSlgrl assumes two satellites and rectennas are built

~~%~e~rlnlng, processing and fabrication

CU. S totals In 1973 dEor ~ropellantmanufacture, launch pad COatln9, Coflstructlon.

eFrOM dun-tin urn and steel processes. fFor ,eCtenna Sites as fraction of tc)td us. kind area

SOURCE Adapted from Env/ronmenta/ Assessment for the Sate///te Power

System Concept Development and Evaluation Program, DOE/ER0069 August 1980
Ch. 8—Environment and Health ● 207

due to the other SPS technical systems. Studies needed to determine the incremental effect of

should be conducted as the design parameters SPS on the environment relative to other elecbecome more clear. Analysis would also be tricity generating faciIities.

HEALTH AND ECOLOGY

Human health and safety could be affected

by launch and space activities, mining, manufacturing, and transport, and the construction

and operation of SPS receiving antennas and

powerlines. These effects and the public

concern about them are likely to be most

pronounced closest to launch and receiver facilities. Long-term exposure to low-level electromagnetic radiation from SPS power transmission and distribution is a critical issue,

involving potential health effects about which

very Iittle is known. For SPS space workers, exposure to ionizing radiation is of the utmost

concern. Other important terrestrial impacts

are shown in table 40. While the effects of

some SPS activities such as mining and manufacturing are fairly conventional and could

be routinely assessed, the uncertainties of

other health and ecological impacts, such as

exposure to microwaves, are great. When experimental data does exist it is rarely directly

applicable to SPS. Furthermore, extrapolation

from experimental animal to human health

and safety standards is tenuous and uncertain

without a good theory on which to base the extrapolation. For other impacts, such as exposure to ionizing radiation, it is not clear if

existing standards should apply to SPS. More

stringent standards can strongly influence SPS

design, cost, and social acceptability. Ecological effects of SPS are also extremely

as little attention has been paid to

plex area.

This second part of the chapter

the health and ecosystem impacts

uncertain

this comwill identify

that presently appear most significant. The first section

will address the bioeffects of terrestrial activities on the public, SPS workers and ecosystems. In the second section, the implications for the health and safety of SPS space

workers will be discussed. With the exception

of power-transmission effects, most of the

health and safety risks described here pertain

to the reference system only. There is not

enough information on the personnel requirements, industrial activities and environmental

impacts to treat adequately the other technical options. It is assumed that many of the

effects would be similar to those of the reference system, varying only in intensity and

degree. It is important to note that some of the

impacts identified for the reference system

could be minimized or avoided by worker

training, protection devices, or changes in the

system design, but the effect of these measures

on concept feasibility and cost need to be

examined in more detail.

Terrestrial Effects

The primary sources of potential health and

ecological effects are electromagnetic radiation from the power transmission and distribution systems and noise and pollution from

launches, mining, manufacturing, and construction (see table 40). The risks to the terrestrial worker are usually greater than to the

general public because of the increased frequency, duration, and intensity of occupational exposure to certain hazards (although

occupational exposure could be more easily

controlled by protective devices). Estimates of

SPS hazards have in many cases been extrapolated from other technologies, such as the

space shuttle. Risk analysis would improve as

the system design becomes more clear. However, the major uncertainties associated with

some effects (e. g., electromagnetic radiation)

rest in the state of biophysical knowledge and

not SPS specifications.
208 ● Solar Power Satellites

Table 40.—Terrestrial Health and Ecological Impacts

Microwaves

● Effects of public and ecosystem exposure to low levels

uncertain

● Occupational exposure higher; may require protective

clothing

Laser Light

• Hazard to people and other living organisms directly exposed to beam

● Hazard to slow airplanes, birds, and insects flying

through the beams

Reflected light (mirror system)

● Ocular effects not expected to be significant; potential

hazard with binoculars not known

. Psychological impacts on public, effects on the

photoperiod of plants and circadian rhythms, and navigation of wildlife are unknown

Reflected light (from reference system)

● Plants and animals would probably not be unduely affected, but many effects are uncertain. The human eye

could be damaged if SPS reflected light were viewed for

too long or with magnifying devices.

High-voltage transmission lines

● Effects of public and ecosystem exposure to electromagnetic fields not well demonstrated but still uncertain (not unique to SPS)

Noise

● Without preventative measures, construction noise from

certain machinery could exceed occupational standards;

no significant public or ecosystem effect is anticipated

● Launch noise and sonic booms couId present problems

for public and ecosystems. Workers would wear heavy

protective devices

Air Pollution

• Without preventative measures, construction of rectennas couId violate standards for certain emissions such as

hydrocarbons and particulate

● Mining, manufacturing, and transport emissions are expected to be comparable to industrial and energy producing processes (except coal)

● Launch effluents are not thought to exceed emissions

standards unless ambient levels are high but studies

must be refined

Ž Effects on ecosystems are unclear

Water Pollution

● Construction and revegetation could deplete or contaminate local water, depending on site

● Onsite facilities would be needed to treat polluted water

at launch site

Safety

• Risks to public, workers, and ecosystems from the handling and transport of toxic and explosive materials such

as rocket propellants

• Occupational risk of catastrophic explosion or launch accident higher than that for public and ecosystems

SOURCE: Office of Technology Assessment.

Electromagnetic Radiation

Over the last few decades, the development

and proliferation of technologies that utilize

electromagnetic radiation has been astoundingly rapid and widespread. However, there is

a growing concern about the biological consequences of exposure to the radiant energy

these devices employ. Terrestrial life as we

know it has evolved in response to a very

specific spectral distribution, diurnal and

seasonal cycle, and intensity of solar and terrestrial radiation. It is possible that the alteration and enhancement of the ambient electromagnetic environment brought about by

modern technologies could have a profound

impact on biological entities and human

health.

SPS would increase the local levels of nonionizing radiation (see fig. 39) in a few areas of

the spectrum, e.g., microwaves, infrared laser

light, or reflected sunlight from the powertransmission system .54 The distribution of

power from the receiving site via transmission

lines would also increase exposure to very low

frequency or static field radiation at some

locations. Light reflected from the surfaces of

space structures and vehicles would be visible

from Earth. Space workers involved in the construction and operation of SPS could also be

exposed to high levels of nonionizing and

ionizing radiation in space.

MICROWAVES

There is not enough relevant data currently

available to assess reliably the biological risks

to humans, plants, and animals exposed to SPS

microwaves. The data base that does exist is incomplete, often contradictory and usually not

directly applicable to SPS.

55 In particular,

5 4P Lorraln and D R Corson, E/ectrornagnetic Fie/ds an d

Waves (San Francisco W.H Freeman, 1970)

5 sprel;m ,nar y fn v;ronmenta/ Assessment for the Sate//ite power

System [SPS) Revision 1, DOE/NASA report No DOE/E R-0036,

January 1980
Ch. 8—Environment and Health ● 209

Figure 39.—The Electromagnetic-Photon Spectrum

Bolometer Sparks

Lamps

Thermopile Hot bodies

Magnetron

Klystron

Crystal Travelling-wave

tube

Electronic Electronic

circuits circuits

AC generators
210 ● Solar Power Satellites

there is a lack of information on the bioeffects

of chronic exposure to microwaves at lowpower densities. Data is presently lacking on

empirical dose-response relationships at these

low levels as well as on the theoretical mechanisms of interaction between Iiving organisms

and microwaves. Improved theory would facilitate extrapolations (which are currently tenuous and oversimplified) from experimental

animal data to the prediction of human bioeffects.

This knowledge is also required for the quantification of SPS microwave risks, without

which no useful assessment of the SPS microwave concepts can be made, If an SPS program is pursued, the study of microwave bioeffects should receive top priority. Microwave

research and future microwave standards

could play a large role in determining the

design and feasibility of SPS systems.

● SPS microwave risks. The SPS reference system microwave environment is illustrated ’in

figure 40. Table 41 presents the public, occupational, and ecosystem exposure levels.

Since the power densities emitted by the

solid-state system are lower as a function of

distance from the rectenna center than the

reference system, they will not be specificalIy addressed here.

No quantitative risk assessment for SPS

workers has been performed or is currently

possible. Occupational exposures would need

to be controlled by adequate protective clothing and shielding, dosimeters (all of which are

not presently available), and possibly changes

in system design.56 The extent of the necessary

protection has yet to be determined. For occupational exposure engendering the greatest

risks, (e. g., space workers and terrestrial personnel working above the rectenna) it might be

necessary to shut off or defocus the micro56prOgram A Ssessment Report, Statement of F;nd;ws, oP c It

wave beam if other protective measures prove

insufficient. Additional research would be required to clarify the risks and protective

criteria for short-term exposure. Possible synergisms between the space environment (e. g.,

ionizing radiation, weightlessness) and microwaves must be explored as well as the plausibility of simultaneously shielding microwaves

and ionizing radiation (see Space Environment). It is also imperative that understanding

of the long-term effects improve substantially

(see below) before a reliable occupational

safety threshold can be determined. In addition, possible disparities between SPS microwave levels and occupational standards in this

and other countries (see table 42) should be addressed, especially if SPS were to be a multinational system. The effects on system cost

and feasibility of implementing protective

measures, complying with safety standards,

and reducing the risks of long-term effects will

need to be analyzed.

Public and ecosystem exposure to SPS microwaves is presently of greatest concern. It

has been estimated that the 60 satellite reference system would raise the ambient microwave level in the continental United States to

a minimum of 10-4 mW/c m

2

.

5 7Although not

directly comparable, this level is two orders of

magnitude greater than the median population

exposure to FM radiowaves. 58 (Ambient microwave and radio frequency levels are inturn 106

times greater than natural levels of solar and

terrestrial radiation.) It therefore appears that

the general population and ecosystems would

be exposed to levels significantly higher than

current background microwave radiation.

The health risks of chronic exposure to

microwaves, especially at these low levels (i. e.,

.

“lbld

“R A Tell and E D Mantiply, “Population Exposure to VHF

and U H F Broadcast Radiation in the United States, ” Proc. IEEE,

68(1 ) 6-12, 1980
Ch. 8—Environment and Health . 211

Figure 40.—SPS Microwave Power-Density Characteristics at a Rectenna Site

0.02 mW/cm2

10 km

13 km

at 35@

I Power denisity is

rectenna center

0.1 mW/cm2 at rectenna

site exclusion boundary

SOURCE: Enwrorrnrenta/ Assessment for the Sate///te Power System Concept Development and Eva/uat/on Program, DOE/ER-0069,

August 1980

Table 41 .—Characterization of Exposure to Reference System Microwaves

—

Outside buffer zone Between 10-4 mW/cm2 and 0.1 mw/cm2

Public

——

Airplane flying through beam Less than 23 mW/cm2 (shielding)

Terrestrial workers Rectenna field Up to 23 mW/cm2 (may be higher if reflections

Space workers

occur)

Transmitting antenna Up to 2.2 W/cm2

Rectenna field:

Ecosystems (plants, Under Outside buffer Less than 0.1 mW/cm2

wildlife, airborne rectenna

biota) Inside buffer Between 0.1 mW/cm2 and 1.0 mW/cm2

Rectenna field: above Up to 23 mW/cm2

rectenna

SOURCE: Environment/ Assessment for the Sate//ite Power System Concept Development and Eva/uat/on Program, DOE/ER-0069, August 1980.
212 ● Solar Power Satellites

Table 42.—Microwave Exposure Limits

Frequency (G Hz) Occupational (mW/cm2) Occupational duration Public (mW/cm2

)

United Statesa 

. . . . . . . . . . . 0.01-100 10.0 No limit None

U. S.S.R.b 

. . . . . . . . . . . . . . . . 0.3-300 0.01 Workshift 0.001

Canada C. . . . . . . . . . . . . . . . . 1-300 5.0 8 hours 1.0

Czechoslovakia . . . . . . . . . . 0.3-300 0.01 8 hours 0.0001

Poland. . . . . . . . . . . . . . . . . . 0.3-300 0.2 10 hours 0.01

Sweden d . . . . . . . . . . . . . . . . 0.3-300 1.0 8 hours 1.0

aThi~ is a ~uid~li”~ ~nlY and is “Ot ~nf~~C.abl~; the ~tarldard~i“ the united Kingdom, German Federal Republic, Netherlands and France are similar to that Of the U.S.

guideline; ANSI will probably recommend 5 mWlcm2 as a new occupational exposure limit. ANSI and EPA are presently considering a new population limit.

bo,l mwlcmz for rotating antennas.

ccanadais proposing a 1 ITrw/cITIz limit at 10 tdHz to 1 GHz ‘requency.

d5 mwlcm~ at o.01 to 0.3 GHz for 8 hours.

SOURCE: Adapted from L. David, A Study of Federal Microwave Standards, DOEINASA report No. DOEIER-1OO41-O2, August 1980.

less than 1.0 mW/cm2) cannot be analyzed with

the current data base. While appreciation for

the complexities of the interaction between

microwaves and biological systems (see app.

D) has grown in recent years, the state of

knowledge, particularly with respect to lowpower microwaves, is immature and incomplete; hence, no assessment for SPS can be

conducted at this time. However, a DOE review of the existing scientific literature identified the biological systems that might be

most susceptible to microwaves. 59 For the public and ecosystems outside of the rectenna,

DOE tentatively concluded that effects on the

reproductive systems would be small; risks to

special populations (e. g., people taking medication, children, older and pregnant people,

etc. ) and effects on behavior would be uncertain and effects on the immune and blood

systems appear unlikely. No cancer, development or growth effects would be expected.

Again, however, the data base on low level

chronic exposure that supports these conclusions is incomplete and more research would

be required to satisfactorily assess potential

effects.

For ecosystems (and SPS workers) at the

rectenna site, effects on physiology, behavior,

development, reproduction and the thermoregulatory, immune and blood systems might

be possible.

60 Of particular concern are the

effects on insects and birds that might fly

59A. R. Valentine, “Environmental Assessment Overview,” In

The Final Proceedings of the Solar Power Satellite Program Review, Apr 22-25, 1980, DOE/NASA report No Conf -800491, July

1980.

‘“I bid

through the beam. Birds in flight are often near

their thermal Iimit and exposure to microwaves might result in thermal overloading. ”

DOE has initiated three laboratory studies to

test the effects on bees, birds, and small

animals at SPS frequency and power densities.

(See app. D.) While no significant effects have

been observed to date, the research is far from

completed .

● Research needs. A workshop organized by

the National Research Council (NRC) recently identified the principal research priorities

for the bioeffects of exposure to low-level

SPS microwaves. 63 These are listed in table

43. Basically, three kinds of laboratory

studies are needed:

1

2

3.

animal laboratory experiments to establish effects empirically as well as doseresponse relationships;

studies of mechanisms of interaction at

different levels of biological organization

(e.g., atoms, molecules, cells, organs); and

improvement of dosimetry, instrumentation and models.

While limited resources might dictate that

these studies be carried out only at the SPS

reference system frequency and power densities, it is clear that research at many frequencies and power densities would help to

elucidate the fundamental mechanisms of

interaction that allow extrapolations to be

made between frequencies, irradiance and

blEnvlronmental Assessment for the Satellite Power System

Concept l)evelopment and Evaluation Program, op cit

‘Zlbld

“Dodge, op cit
Ch. 8—Environment and Health • 213

Table 43.—Research Needs To Help Reduce Uncertainties Concerning Public Health Effects Associated With

Exposure to SPS Microwave Power Densities and Frequency

—

Local or general thermal effects

●

●

●

●

●

●

●

●

●

Long-term experiments at power densities< 0.1 mW/cm2

at whole body, organ, and organelle levels, testing for biological endpoints such as alteration of enzyme reaction

rates and cell membrane confirmational changes.

Studies of basic physical interactions of electromagnetic

fields with molecular components of living tissue, to develop models of biological effects or phenomena. (For example, biophysical experiments are required to determine the role of microwaves at SPS frequencies and intensities at the molecular level and their action on ionic

conductivity. Any responses, biological, biochemical, or

physical, should be investigated from the point of view of

alteration of enzyme reaction rates, and cell membrane

phase transitions and confirmational changes.)

Better dosimetry techniques for calculating and measuring (such as a probe that could be used within an

organism to measure in a nonperturbing way) internal

field patterns.

Interactions with drugs or other chemicals

Repeat selected experiments showing effects (including

the potential of microwaves as a cocarcinogen), using

carefully controlled dosimetry and statistical analysis.

Develop and test hypotheses to explain effects.

Long-term dose-response experiments at power densities around 0.1 mW/cm2 and with a larger number of

drugs at whole body, organ, and organelle levels.

Immunological effects

Repeat selected Russian research at 1 to 500 mW/cm2

levels; repeat selected U.S. work to validate it.

Mechanistic and molecular biological experimentation.

Long-term studies, particularly autoimmune response.

——. .

●

●

●

●

●

●

●

●

●

●

●

Effects on calcium ion efflum in brain tissue

Studies to determine bioeffects using 2450 MHz as the

carrier frequency or studies to determine whether the

power density “windows” are carrier-frequency dependent.

Studies to establish the interaction mechanism (the interaction site) of the modulated fields and ELF fields on

calcium ion efflux.

Studies to determine whether the phenomenon will occur

under the modulation and power characteristics expected of the SPS microwave beam.

Studies to determine whether the calcium ion efflux

phenomenon correlates with Russian and East European

findings of neurological/behavioral decrements in people

and animals exposed to low levels of microwaves.

Experiments to determine whether other ions—sodium,

potassium, magnesium–are similarly affected.

Effects on organized structures

Studies of changes in behavioral responses under

simulated SPS conditions, using behavioral tests (such

as time-based schedules of reinforcement) that are both

sensitive and reliable measures of such effects.

Studies of long-term effects.

Neurological and blood-brain barrier experiments at low

levels.

Determine the neurological an d physiological

significance of behavioral responses.

Molecular level studies on biological relaxation times.

Consideration of long-term animal experiments at 2,450

MHz to evaluate, if possible, whether there is any trend

toward life shortening in animals.

SOURCE: C H. Dodge, (rapporteur), Workshop on Mechanisms Under/y/ng Effects of Long-Term Low-Level, 2.450 MHZ Rad/at/on on Peep/e, organized by the National

Research Council, Committee on Satelllte Power Systems, Environmental Studies Board. National Academy of Sciences, July 15.17, 1980

species. It may also be possible that frequencies other than 2.45 GHz would be used for

SPS. If a much different frequency were used,

however, low-level microwave research would

have to be done at that frequency as well,

because different frequencies cause different

responses,

In addition to laboratory experiments, epidemiological studies are also needed. 64 It has

been argued that such studies are currently of

limited usefulness; they are very expensive, difficult to accurately document (i.e., it is difficult to determine the dose to which individuals are exposed) and may overlook important

biological endpoints. 65 In addition they have

“Office of Science and Technology Policy, A Technica/ /7eview of the Biological Effects of Non-lonlzlng Radiation, Washington, D C , May 15, 1978

65paul Tyler, Armed Forces Radiological Research Institute ,

private communication, July 30, 1979

limited usefulness for exposure to low levels of

microwaves because the variability of the response is small and might be masked by other

effects. It is also not clear how many people

would need to be observed. Nonetheless a

coordinated program of prospective epidemiology (as opposed to retrospective studies

that rely on medical records many years after

exposures) and laboratory research is essential

to bridging the gap between biological effects

observed in a laboratory animal and human

health standards.

Special attention must also be paid to effects on ecosystems. To date, nearly all studies

have been conducted in a controlled laboratory environment on a relatively few species.

Virtually nothing is known about the effects of

microwaves on a complete ecosystem and no

studies have been performed that even ap-
214 • Solar Power Satellites

preach the projected time scale of SPS operation (i.e., 30 to 100 years). With respect to SPS,

it must be determined if animals and airborne

biota would be attracted to the beam or would

avoid it. What impact would microwaves have

on the navigational systems of birds and insects (as well as aquatic life for offshore

rectennas)? What effect would exposure to

microwaves have on the productivity of plants

and their susceptibility to drought? How would

SPS affect the local food chain? The effects on

micro-organisms, such as bacteria, fungi, and

algae should be invest igated. 66

● Microwave standards. The biological consequences of exposure to low-level microwaves are poorly understood because of

inadequate and sporadic support of microwave bioeffects research in general and

because the bulk of research performed in

this country has focused on the bioeffects at

levels of 10 mW/cm2 or greater. 67 This emphasis stemmed from a belief that the only

biologically significant damage from exposure to microwaves is due to heating. In

fact, occupational guidelines developed in

the 1950’s through the Department of Defense and its contractors in response to concerns about exposure of radar personnel

were based on biological injuries (e. g.,

cataracts, burns) from acute exposure to

microwaves on the order of 100 mW/cm2

. It

was concluded that humans could well tolerate exposures to power densities 10 times

smalIer 68 (i. e., 10 mW/cm2

) without suffering

serious or permanent damage. 69 This reasoning was accepted by the American Standards

Association (now the American National

““0 P Gandhi , “ Blohazarcf~ ot Microwave Beams From Prc~-

posed Satel Ilte f]ower St~tlon~’, I n 1 ~ea /th /rnp/lcatlon$ of New

f nergy Tccfrno/oKlc\, W N Rom and V [ Archer (eds ) (Ann Arbor, MI( h Ann Arbor Scien{ e Publ l~her~ I n( , 1980)

“7P Tyler, “Overview of Radlatlon Rt’sear( h Past, f’resent and

Future, ” I n B Io/oHIca / / ffec ( $ 0 f Nom Ion IZ Inx Racf Ia t Ion, P Tyler

(ecf ) (New York Academy of Science\, annal~, VOI 247, 1975)

““R Bower\, et al , ( ommun~catfon~ for a Mof)I/e $ocrety (Beverly H I I Is, Ca I If \age PLI bl I cat Ion\, 1978) ( Bel I [ aboratorles and

General F Iectrl[ rec ommencfeci () 1 nlW ( m’ and 1 () rnW/cm’

re~pect Ively as maxr m um perm I\\ I ble expofure I Im Its )

““N H Steneck, H j Cook, A j Vancfer, and C 1 Kane, “Th e

Origln$ of U S Safety Standard\ tor Microwave Kadlatlon, ’

$c/cnce, VOI 208, pp 1230-1237, j une 1 ], 1980

Standards Institute (ANSI) which in 1966

recommended a maximum permissible exposure of 10 mW/cm2

, averaged over any 6-

minute period (1 O to 100 GHz).70 This rationale also forms the basis of the current

U.S. occupational guideline (which in 1975

was ruled advisory rather than a mandatory

standard”) as promulgated by the Occupational Safety and Health Administration

(OSHA) which adopted the ANSI recommendation in 1971. Presently, there is no official

recommendation for general population exposures in this country.

The reasoning underlying the U.S. guideline

is currently in dispute and OSHA and ANSI are

considering new recommendations. 72 73 T h e

confIict centers around the assumption that

only thermal effects result from exposure to

microwaves. While it is generally acknowledged that exposure to microwaves of 10

mW/c m

2 or greater will result in heating, the

effects and consequences of exposure to lower

power densities are controversial. Experiments

documenting behavioral and neural changes

and the enhancement of calcium efflux from

brain cells74 in particular have suggested the

existance of other effects at power densities

below 1.0 mW/cm

2

. These phenomena are

thought by some to result from direct interactions with the electromagnetic field rather

than as an indirect consequence of heating.

Some of the mechanisms that have been postulated for non ionizing radiation include:

1. distortion of the shapes of individual

molecuIes or rearrangement of a group of

molecules that might transiently or per-

——..

‘“L David, A Study of Federal Microwave Standards, DOE I

NASA report No DO E/E R-10041-02, August 1980

7 ‘General Accounting Office, Efforts by the Errvironrnenta/ Protection Agency to Protect the Public From Environmental NonIon\zrng Radiation Exposures, Washington, D C , Mar 29, 1978

‘ A W (;uy, “Non-l onlzlng Radiation. Doslmetry and lnteractlon, ” I n Non-Ionizing Radiation, proceedings of a Toplca I Symposium, Nov 26-28, 1979, The American Conference of Governmental I ndustrlal Hyglenlsts, I nc , 1980

“‘Z R (;laser, “Basis for the NIOSH Radiofrequency and Microwave Rad Iatlon Criterl a Document, ” In Non-Ionizing Radiation. proceedings of a Topical Symposium, Nov 26-28, 1979, The

American (-onference of Governmental I ndustrlal Hyglen ists,

Int , 1980

“Dodge, Op clt
Ch. 8—Environment and Health ● 215

manently alter the function and replication process of a biological unit;75

2. reorientation of dipole molecules in the

microwave field and polarization of molecules that control membrane permeabiIity; 76

3. biological electromagnetic interference in

which the microwave field disrupts or enhances the transfer of biological information in the form of electromagnetic

energy between molecuIes and celIs; 77

and

4. field receptor interactions where neural

tissue acts as a receptor of weak fields. 78

The discussion of low-level effects is

hampered by the experimental difficulties of

isolating the various possible mechanisms.

Most U.S. microwave experts acknowledge the

need for research on low-level effects, but remain skeptical about their biological significance, especially at the proposed SPS single

frequency of continuous radiation.

The controversy over low-level effects has

been fueled by the disparity between U.S. and

U.S.S.R. research and exposure standards (see

table 14)—the Soviet standard is three orders

of magnitude lower than the U.S. guideline.

Some U.S. authors have attributed the different standards to dissimilar research philosophies. 79 For example, microwave studies

thought most valid by U.S. scientists are those

performed in a controlled laboratory environment, whereas Soviet researchers rely on clinical and “subjective” data as well. 80 In fact,

based on the complaints of radar personnel,

“K D Straub, “Molecular Absorption of Non-Ionizing Radiation in Biological Systems” In The Ph yslca / Basis of Electromagnetic Interactions With Bio/ogica / Systems: Proceedings of a

Workshop, University of Maryland, june 15-17, 1977, L Taylor

and A Cheung (eds ), US DHEW, 1978, report No [FDA) 78-8055,

Washington, D C , April 1978

“A S Pressman, E/ectromagnet~c F)e/ds and Life (New York

Plenum Press, 1970)

“lbld

“D R Justesen, et al , “Workshop on Radiation: Scientific,

Technological, and Soclologlcal Implications of Research and

on Biological Effects of Radio-Frequency E Iectromagnetic Radiations, ” In Proceedings of the 1978 Conference on U.S. Technical

Po/icy (New York. IEEE, 1979)

“W C Milroy and S M Michelson, “The Microwave Controversy, ” /nternationa/ journa/ of Envlronmenta/ Studies, VOI 4, p

123, 1973

‘“D R J ustesen, Veterans’ Admlnlstratlon, private communication, J u Iy 16, 1979

“microwave sickness” has been isolated as a

distinct occupational disease in the U. S. S. R.”

It has also been argued that the Soviet exposure levels are based on the occurrence of a

biological effect whereas the U.S. guideline

reflects levels of known biological damage

(with a safety margin). ” Moreover, it has been

claimed that the Soviet standard has been set

without regard to the practical feasibility of

meeting such low levels. It is further argued

that in any case the standards are not enforced, especially in the military sector,

although this would be difficult to substantiate.

For many years the flow of information between East European and Western researchers

was restricted. Translation problems sometimes also contributed to misunderstandings.83

This situation has improved considerably, and

attempts are being made in the United States

to replicate many of the low-level experiments

performed in other countries (although the

United States still has not sponsored any

clinical studies). Western literature is also

beginning to acknowledge the possibility of

behavioral response and selective sensitivity

of organs to low levels .84 Partly for these

reasons, it is anticipated that new ANSI guidelines will be established that are more stringent

than the present exposure levels (see fig. 41). At

the SPS frequency of 2.45 GHZ, the maximum

occupational exposure that is now being considered is 5 mW/cm2

. * EPA is also considering

—.—

“C H Dodge and Z R Glaser, “Biomedical Aspects of Radio

Frequency and Microwave Radlatlon A Review of Selected Soviet, East F u ropean, and Western References” I n Bio/ogica/ Effects

of E Iectromagnetic Waves: .Se/ected Papers of the USNC/URSl

Annual/ Meeting, L L Johnson and M Shore (eds ), Boulder,

COIO , October 1975, USDHEW, (report No (FDA) 77-8010/8011),

Washington, D C 1976

“[1 Mlchaelson, In Symposium on the Bio/ogica/ Effects and

Health /mp/lcations of Microwave Radiation, S Cleary (ed ),

RI( hn~ond, 1969, USDHEW, report No BRH/DBE 70-2, 1970, pp

76-81

“‘F’rzemyslaw Czerskl, Department of Genetics, National Resear( h I nstltute of Mother and C h ild (Poland), private commu n icatlon Sept 5, 1979

“’C H Dodge and Z R Claser, “Trends In Non-ionizing Electromdgnetlc Radlatlon Bioeffects Research and Related Occupational Health Aspects,” Iournal of Microwave Power, VOI 12,

No ~ 1977, Pp 319-334

*Thl\ level has been criticized by the National Resources

Defense Councrl as being arbitrary and not found with any

recognition of possible nonthermal effects, see ch, 9, Pub/ic

/5 $11(?’>
216 ● Solar Power Satellites

Figure 41 .—Comparison of Exposure Standards

1 0

1

, 0 0

1

SOURCE: A. W. Guy, “Nonionizing Radiation: Dosimetry and Interaction,” in

NonionizingI?adiationj Proceedings of a Topical Symposium, Nov.

26-28, 1979, The American Conference of Governmental Industrial

Hygienists, Inc., 1980.

the development of exposure guidelines for

the general population, although it does not

have the jurisdictional authority to enforce

standards. It is conceivable that future public

standards could be established at 1.0 mW/cm2

or below.

8 5 The impact of more stringent

standards on SPS design and concept viability

should be addressed.

Agencies. At present, the study of the bioeffects of nonionizing radiation falls under the

jurisdiction of 13 Federal agencies.86 The allocation of funds (currently about $15 million

per year) is shown in figure 42. The agencies

primarily responsible for regulation and the

establishment of microwave guidelines87 in-

*’David, op. cit.

8bF;fth Report on “program for Contro/ of Electromagnetic po/-

Iution of the Environment: The Assessment of Biological Hazards

of Nonionizing Electromagnetic Radiation, ” NT I A report No

79-19, U.S. Department of Commerce, March 1979.

87 David, op cit

Figure 42.— Program Funding

FY-77 FY-78

$7.6 M $10.1 M

SOURCE: Fifth Report on “Program for Contro/ of Electromagnetic Po//ution of

the Environment: The Assessment of Biological Hazards of NonionIzmg Electromagnetic Radiation, ” NTIA report No. 79-19, U.S. Department of Commerce, March 1979.

elude the Department of Health and Human

Services (the Bureau of Radiological Health/

Food and Drug Administration, for example,

sets emission standards for electronic products

such as microwave ovens); the Department of

Labor (which sets occupational guidelines);

and EPA (which sets environment guidelines

for other Federal agencies).

The Federal effort has been coordinated at

various times by other Federal agencies, but a

clear, dedicated, well managed and adequately funded national program in microwave bioeffects research is currently lacking.

To some extent, the ineffectiveness of the

agencies responsible for the management of

the Federal program is due to lack of control
Ch. 8—Environment and Health ● 217

over the allocation of research funds .88 It is

also often the case that within each of the

research and regulatory agencies, microwave

research receives low priority on the agency’s

agenda. jurisdictional ambiguities hav e

caused some agencies to take a limited approach to research and protection. Multiagency effort has also made public participation and education difficult.

Often, the most cohesive and vigorous research and evaluation of microwave bioeffects

take place in conjunction with one particular

technology such as a radar facility. This is not

always the best arrangement since in the past,

user agencies with vested interests have often

been responsible for the assessment of health

and environmental impacts. Moreover, fundamental research is needed in order to elucidate

the mechanisms of interaction; technoiogyspecific research is helpful but usually does

68 Tyler, op cit

not contribute significantly to basic understanding. In addition, long-term continuous

studies are needed and project-specific research is sporadic and unpredictable.

Nonetheless, unless the Federal research effort is consolidated into fewer agencies and

given greater support, it is likely that an SPS

program would be required to sponsor microwave bioeffects studies as it did in the DOE

assessment. If the current climate continues,

this research would not only gather information specifically relevant to SPS, but would

probably be quite fundamental in nature. If a

microwave SPS program is pursued, the development of SPS would entail the involvement

of the Federal agencies shown in table 4 4 .

State agencies might also be affected.

Conclusion. DOE-sponsored microwave

studies stimulated thinking about the design of

microwave bioeffects experiments, tended to

clarify research needs and obstacles and conTable 44.—SPS Development

SPS development phase Microwave aspect Agency involvement

Basic research . . . . . . . . . . . . . . . . . . .

Applied research . . . . . . . . . . . . . . . . .

Exploratory development . . . . . . . . . .

Technology development . . . . . . . . . .

Engineering development. . . . . . . . . .

Demonstration . . . . . . . . . . . . . . . . . . .

Commercialization. . . . . . . . . . . . . . . .

Production . . . . . . . . . . . . . . . . . . . . .

Operations . . . . . . . . . . . . . . . . . . . . .

Environmental and public health effects -

-

— —— . . .—. . .. —- . . . . - .

evaluation MPTS technology

Conduct experiments and further define

health and safety risks of MPTS to

public, the environment and SPS

workers

Preliminary standards development

radiation exposure standards

occupational health and safety

standards development

Final standards for MPTS chosen

occupational health and safety

standards finalization

Preparation of environmental impact

Guidelines for health and safety

(worker) enforcement

Guidelines for public health and safety

environmental impact statements

Review guidelines for worker

health and safety

Review guidelines for public health

and safety

Enforcement of guidelines for

worker health and safety

Enforcement of regulations for

public health and safety

Enforcement of guidelines for worker

health and safety

Enforcement of guidelines for public

health and safety

DOE, EPA, HEW/FDA, NASA

DOE, NASA, HEW/FDA, Department of

Labor/OSHA EPA

HEW/FDA, DO E/EV, EPA, HEW/FDA,

Bureau of Radiological Health, Department

of Labor/OSHA

HEW/FDA, DOE/EV, EPA, DOL/OSHA

Council on Environmental Quality

Department of Labor/OSHA

HEW/FDA-Bureau of Radiological Health,

EPA, Council on Environmental Quality

Department of Labor/OSHA

HEW/FDA, EPA

Department of Labor/OSHA

EPA

Department of Labor/OSHA

EPA

SOURCE: L. David, A Study of Federa/ M/crowave Standards, DOE/NASA report No DOE/ER-10041 .02, August 1980.

83-316 0 - 81 - 15
218 Ž Solar Power Satellites

tributed to an increased study capability.

While the results of these studies are useful,

the time and resource constraints of the SPS

assessment program precluded a thorough research agenda; in particular, no studies on

long-term exposure to low levels of microwaves could be initiated and little more could

be done to improve our theoretical understanding. In spite of the general acknowledgment by the microwave community of the

need for studies of chronic, low-level exposure,

practically no such studies are underway or

planned. Clearly, if many of the fundamental

questions about the bioeffects of microwaves

are to be resolved within the next one or two

decades, a more comprehensive, dedicated national research program will be needed.

LASER LIGHT

The biological risks associated with the laser

system have been assessed only to a very Iimited degree. The power density of the focused

laser system beam would be sufficiently great

to incinerate biological matter.”’ Safety measures (such as a perimeter fence and pilot beam

system) would have to be devised in order to

avoid beam wandering and the direct exposure

of the nearby public and ecosystems. Less easy

to protect would be birds and insects flying

through the beam; without some sort of warning device they wouId be incinerated.90 It is not

known if air-borne biota would be aware of the

beam, and if so whether they would be attracted to or avoid it. Siting studies should

consider migratory flyways and local bird

populations.

It has been suggested that aircraft be restricted from the power beam area. 91 While it

is not expected that jets and their passengers

would suffer any damage in traversing the

beam due to their high speed and infrared reflectivity, slower flying, less reflective aircraft

could be affected. More important, laser light

specularly reflected from an airplane would

present an ocular hazard to the public. 92 A

radar warning system might be devised to de-

“’Beverly, op clt

‘OWalbrldge, op clt

9’ Beverly, op clt

92 Walbrldge, op clt

focus the laser beam if a plane did happen to

fly through it.

The primary risk to the public and nearby

ecosystems outside of the direct beam wouId

be due to laser light scattered from clouds,

dust and the receptor site. This “spill over” of

laser power (less than 1 percent) would necessitate establishing a buffer zone surrounded by

an opaque, talI fence. 93 As shown in figure 33,

it has been estimated that a protection radius

of 300 to 800 m wouId be required in order to

limit public exposure at the perimeter to 10

m W/cm a recommended maximum wholebody irradiance limit.94 More research would

be needed to verify this exposure guideline

and to investigate the effects of chronic exposure to low level laser radiation. For visible

Iaser beams, the risk of ocular damage could

be increased at the receiving site if magnifying

devices were used. Prolonged occupational exposure at infrared power densities greater than

10 mW/cm2 would be of particular concern,

especially for the cornea. Workers at receiving

sites wouId probably be required to wear protective clothing and eye goggles.

Hazards outside of the site have not been

assessed. It is unlikely that wildlife or vegetation at the receptor site would survive. 95 T h e

etfects of the low level laser Iight on ecosystems outside of the receptor area are not

known It is possible that certain infrared sensitive Insects would be attracted to the laser

beam, but this requires further study .9’

The bulk of research on the biological effects of lasers is not directly applicable to the

infrared lasers that have been suggested for

SPS Most studies have concentrated on the

effects on the eyes and skin of visible and near

infrared lasers in a puIsed mode. The standards

that have been promulgated pertain predominantly to short-term occupational exposure to

———

‘ ‘Beverly, op clt

‘“[3 H Sllney, K W Vorpahl, and D C Wlnburn, “Envlronnlenta I H ea Ith Hazards From H lgh-Powered I nfra red Laser DeV I <-e $ ‘ ‘ \rch Envlronmenta/ Ffea/th, VOI 30, April 1975, pp

174170

“‘W~lhrldge, op clt

““lhl(i
Ch. 8—Environment and Health ● 219

lasers operating in a controlled indoor environment such as a laboratory or medical facility.

Few studies have examined the effects of

chronic exposure at SPS-like power densities

and under SPS environmental conditions. A

summary of known effects on the skin and

eyes is presented in appendix D.

REFLECTED LIGHT FROM THE MIRROR SYSTEM

The light reflected by the mirror system to

Earth would be visible at night as a general

glow at up to 150 km from the receiving site. ”

The potential health impact of most concern is

ocular damage from either the scattered light

or from direct exposure to reflected light as

the mirror image sweeps across the Earth during orientation maneuvers. Since the CoIIective

intensity of all the mirrors at one site would be

equal to that present in the desert at noon, it

appears that the intensity of Iight would be too

low to be of danger to the observer. One investigation revealed that under the worst conditions (i.e., staring, no blinking) it would be

safe to view the mirrors directly for at least 2.4

minutes. ” No information is available regarding the ocular effect produced when an individual views the mirrors with a binocular or

telescope. The psychological effects of a “24-

hour day” or aIterations of the sky near the

sites also needs to be studied.

The ecological impacts have not been assessed. It is known that the polarization, frequency and intensity of light as well as the

percentage of daylight hours influence the

behavior, navigation, and lifecycle of many

species of wildlife and vegetation; many

species have inherent biological clocks or circadian rhythms that are triggered by the diurnal and seasonal variations of sunlight.

9 9

However, ecosystems in the area surrounding

the receiver site would be exposed to low

levels of incremental sunlight and so it does

not appear Iikely that significant biological ef97 Billman, private communlcatlon, op clt

‘*M T Hyson, “Sunllght ReflectIons From a Solar Power Satellite or SOLARES Mirrors Should Not Harm the Eyes, ” In The Flr-ra/

Proceeding of the Solar Power .$atellite Program Review, Apr

22-25, 1980, DOE/NASA report No Conf -800491, July 1980

“McGraw-Hi/l Encyclopedia of Science and Technology, V OI

10 (New York McGraw-Hill Book Co , 1977)

fects would occur. Nonetheless, research

should be conducted in this area. The effects

of changing the night sky also need to be

studied for ecosystems both near and distant

from the site. Ecosystems could also be indirectly affected by weather modification induced by the mirror system.

LIGHT REFLECTED FROM REFERENCE SYSTEM

The transportation vehicles, construction

and staging bases, and the satellite structure of

the orbiting satellite systems will reflect

sunlight, discernible on Earth. Some specular

reflections from reference system components

may be exceptionally bright due to their large

size, low altitude, and reflectivity. 1oo Mos t

specular reflection would be restricted to

small, fast moving spots or “glints” as the

structures and vehicles change orientation.

The worst cases, which may exceed acceptable

limits, occur for reflections from the solar

panels of the OTVS while in LEO, and the back

of the solar panels in CEO. Diffuse reflections,

brighter than most stellar sources would make

the LEO OTV staging base visible during the

day It may be possible to reduce most of these

reflections by controlIing the orientation, surface curvatures, solar panel alignment and surface quality of the vehicles and structures.

Reflection of visible light from the components of other SPS technical options may be

similar to the reference system depending on

the orbit and size of transportation vehicles

and space structures.

The effects on the public and ecosystems

have yet to be evaluated in depth. One study

found that the reflections from the reference

system would be bright but not dangerous to

the human eye101 unless viewed for too long or

with a magnifying device. Studies would be

further needed to evaluate the ground illumination in terms of human exposure limits

and to explore any possible psychological effects While DOE has tentatively concluded

that plants and animals would not be unduly

“’(’D [ Llemohn, D H Tlngey, and B R Sperber, “Characterizat lorl of Reflected L Ight From the Space Power System, ” In The

Findl Proceed)ngb of the Solar Power Satellite Program Revfew,

Apr IL 25, 1980, DO E/NAsA report No Conf -800491, ) uly 1980

‘‘“ I+v\on, op cIt
220 • Solar Power Satellites

affected by the reflected light, ecosystem effects are largely uncertain. More research

would be needed to investigate how alterations of the day and night sky could influence

behavior, navigation, and Iifecycles of wildlife

and vegetation.

Noise

Noise is generated during rocket launches

and the construction of receiving stations.

With respect to the latter, the highest nois e

levels would result from heavy equipment

used to prepare the site and build the support

structure. The DOE prototype siting study concluded that it would be unlikely that significant noise-related impacts on the public and

most animals located 2 km or more from the

prototype construction site would occur. ’ 02

For some machinery, occupational noise

standards would be exceeded. Mitigation

measures include ear protection devices, mufflers for machinery, and special insulation in

factories.

Very high noise levels would be associated

with launch vehicles during ascent and reentry.

Table 45 presents the estimated noise produced by the HLLV. Table 46 is exhibited for

comparison. A preliminary assessment indicates that the OHSA standard of 115 db(A)

would be exceeded within 1,500 m of the

launch pad, and the EPA guideline violated

within 3,000 m. 103 Using the Kennedy Space

Center as a prototype launch site, the study

“

)

’ Protot ype Envlronmenta/ Assessment of the /mpacts of $Irlrrg

and Construct~ng a Sate//fte Power $ y~rem ( SP$) Ground /7ecelvIrrg Stat Ion (C RS), op c It

“’JEnvlronmenta/ Assessment for the \ate//lte Power System

Concept Development and Eva/uat/on Pro#ram, op clt

Table 46.—Representative Noise Levels

Due to Various Sources

Source or description of noise - Noise level (db)

Threshold of-pain . . . . . . . . . . . . . . . . . . . . . . 120

Riveter 95

Elevated train” . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . . 90

Busy street traffic. . . . . . . . . . . . . . . . . . . . . 70

Ordinary conversation . . . . . . . . . . . . . . . . . . 65

Quiet automobile . . . . . . . . . . . . . . . . . . . . . . 50

Quiet radio in home . . . . . . . . . . . . . . . . . . . . 40

Average whisper . . . . . . . . . . . . . . . . . . . . . 20

Rustle of leaves. . . . . . . . . . . . . . . . . . . . . . . 10

Threshold of hearing . . . . . . . . . . . . . . . . . . . 0

— —. —

SOURCE Errv/ronrnenfa/ Assessment for tire Satelllte Power System Concepf

Development and Evaluatlorr Program, DO EIER-0069, August 1980

concluded that launch noise wouId not interfere significantly with speech (interruption for

2 minutes at 30 km twice a day), but that interference with sleep could occur 30 km from the

site Table 47 presents an estimate of the

number of people annoyed by the noise as a

function of distance. Sonic booms would also

be generated; pressure levels are shown for

HLLVs and PLVs in table 48. The HLLV sonic

booms would not cause injury but would invoke gross body movements and might interfere with sleep. It has been suggested that the

trajectories of launch vehicles should avoid

population areas.

The effects of noise on wildlife include startle responses and disruption of diurnal and

reproductive cycles that could be particularly

significant in endangered species habitats. It

has been suggested that wildlife would adapt

to the noise, but this is not clear. ’04 While the

noise generated by the space shuttle is not expected to be serious, the effects of HLLVs

wouId be greater because of the increased fre-

— —. .

“ ‘Ibid

Table 45.— Estimated Sound Levels of HLLV Launch Noise

——

Distance from launch pad

.

Sound level and duration 300 m 1,500 m 3,000 m 9,000 m 30,000 m

OASPL a (dB) . . . . . . . . . . . . . . . . . . . . 149 136 130 120 109

A-level b [db(A)] . . . . . . . . . . . . . . . . . . . 130 114 105 89 72

Duration(s) . . . . . . . . . . . . . . . . . . . . . . 12 42 54 77 77

aOASPL: overall sound pressure level expressed In decibels (db) above the level corresponding to a reference pressure of 20 pa (pa= Pascal = 1 N/mz)

bA-ievei: Weighted average sound level over the frequency spectrum In accordance with the Performance of the human ear

SOURCE: Env/ronmenta/ Assessment for the Sate//lte Power System Concept Deve/opmerrf dftd Eva/uat/on Program, DOE/ER-0069, August 1980
Ch. 8—Environment and Health Ž 221

Table 47.–Community Reaction to HLLV

Launch Noise

Percent of people highly

Distance from launch point (m) annoyeda

300 . . . . . . . . . . . . . . . . . 90

1,500 . . . . . . . . . . . . . . . . . . . . . 45

3,000 . . . . . . . . . . . . . . . . 24

9,000 . . . . . . . . . . . . . . . . . . . . . 5

30,000 . . . . . . . . . . . . . . . . . . . . . 1

aBa~edon a24.hraverage of thenowe

SOURCE Env/ronmenta/ Assessment for the Sate///(e Power System Concept

Deve/opmentand Eva/uat/on Program DOE/ER-0069, August 1980

Table 48.—Sonic Boom Summary (Pa)

———

Vehicle Launch Reentry

HLLV booster . ‘1 ,200 190

HLLV orbiter . . . . . . . — 140

PLV booster. . . . . . . . 770 140

PLV orbiter. . . . . . . . . — 70

SOURCE Env/ronmenfa/ Assessment–for the Sate///te Power System Concept

Deve/opmenf and Eva/uat/on Program DOE/ER-0069, August 1980

quency and level of noise, due especially to

sonic booms.

Terrestrial workers would be exposed to

noise levels higher than the general public and

wouId require hearing protection. 105 Possible

hearing damage and pyschological effects

should be studied in Iight of the unprecedented frequency and size of launches.

Other Risks

Quantitative studies are needed to determine SPS impacts on air and water quality and

the generation of solid wastes. It is currently

assumed that these impacts would be comparable to typical industries and powerplants (except coal) and that unusually high risks would

not be encountered by the public and terrestrial workers that could not be minimized or

corrected. ‘)() The effects on ecosystems are

less certain.

DOE has concluded that acid rain from the

SPS launch ground cloud would be localized,

temporary and minimal. Because of the consequences of ozone depletion, i.e., a l-percent

“)’lbld

“’hlbld

decrease in ozone corresponds to a 2-percent

increase in biological harmful ultraviolet

radiation that reaches the Earth, 107 the effects

of SPS on the ozone layer has been studied.

preliminary analysis concludes that the change

in ozone brought about by SPS launch effluents would be negligible, but further study is

requ i red. 108

The deployment of SPS would also require

the mining, production, and transport of certain toxic materials. Some toxic materials such

as hydrocarbons could also be released from

fuel burning in the launch and recovery of

space vehicles. Rocket propellants such as liqu id hydrogen are of special concern because

they are toxic, flammable, and explosive. 109 A

spill of liquid oxygen would adversely affect

local ecosystems. However, no information is

available to quantify the exposure or risk to

the public, workers or ecosystems. An incremental increase in the risk of catastrophic explosions or fire is thought possible, especially

because of the large amount of fuels involved;

the occupational risk, of course, being considerably higher than that for the public.

Launch and recovery accidents are not likely

to have any more impact on the public than

conventional aircraft accidents, although it

has been suggested that flight trajectories

avoid populated areas. The noise and shock

waves from a catastrophic explosion of an

HLLV could possibly blow out windows and

doors in buildings up to 15 km from the launch

pad ‘‘

Space Environment

Many space workers would be needed to

construct and maintain an SPS system. The

reference design, for example, requires 18,000

person-years in space; 112 workers would serve

ten 90-day tours over 5 years. Other SPS designs may have different personnel requirements, but they will not be specifically ad-

“)’} Hamer, “Ozone Controversy, ” Editor/a/ Research Reports,

VOI 1, No 11, 1976

‘‘“l bl[i

““l bld

‘ “)1 bid

‘ ‘ ‘ Ibid

‘‘ ‘Program Assessment Report, Statement of Findings, op clt
222 • Solar Power Satellites

dressed here. The health effects of the space

environment are potentially serious, but highly

uncertain; experience with people in space is

limited to a few highly trained astronauts who

lived mostly in LEO for a maximum of a few

months. 113 NASA’s current ground-based program as well as future activities with the space

shuttle and space operations center will yield

information relevant to SPS space worker

health and safety. DOE does not consider the

potential health effects an obstacle to continued planning and development of SPS, 114

but if this and other space projects are to be

considered, the health and safety of space personnel should be a high-priority research task,

The principal health and safety risks of the

space segment of SPS are illustrated in figure

43. Effects on the general health and safety of

space workers such as acceleration and

weightlessness are discussed in appendix D.

The most serious potential health risk of the

space environment is exposure to ionizing radiation. The types of radiation found in the

different SPS orbits are listed in table 49.

Exposure to radiation in CEO and in transit

between LEO and CEO are of most concern

because, under the reference system scenario,

workers spend approximately 91 percent of

Figure 43.— Factors Pertinent to Space Worker Health and Safety

Space structure

charging High voltages

Electric and \ / Construction

Transport ce debris

accidents eoroids

accidents

Construction

accidents

o

Space debris

Transport accidents

Life p

failure

transport accidents

acceleration/deceleration

SOURCE Program Assessment Report Statement of Findings

DOE/E R-0085 November 1980

Satelltte Power Systems ;oncept Development and Evaluation Program, DOE/NASA report No
Ch. 8—Environment and Health ● 223

Table 49.—Types of Radiation Found in the

Different SPS Orbits

GEO

● Radiation belts

—Electrons—dominant when shielding is less than

3gm/cm2 aluminum

—Bremsstrahlung —produced by electron interactions with

shielding—dominant when shielding is greater than

3 gm/cm2 aluminum

—Protons—low energy—stopped by minimal shielding

● Galactic cosmic rays

—Protons

—Helium ions

—High-energy, heavy ions

● Solar particle events— i.e., particles accelerated to high

energies during a solar f I are

—Protons

—Heavy nuclei

Travel Between Orbits

• Radiation belts

—Bremsstrahlung radiation produced by electrons

—Protons

LEO

. South Atlantic Anomaly

—Protons

—Electrons—low energy—stopped by minimal shielding

SOURCE: Margaret R. White, Lawrence Berkeley Laboratory, private communication, Feb. 12, 1981

their time in the higher orbit where the radiation environment is the most severe. 115 In GEO,

except under the unusual circumstance of a

large solar flare, the major part of the radiation dose in the reference system would be due

to bremsstrahlung produced by the interaction

of high-energy electrons with the shielding

material. The biological effects of this kind of

radiation are reasonably well understood, and

innovative shielding might reduce this dose.

However, radiation from the high-energy,

heavy ions (HZE) in galactic cosmic rays cannot be stopped by conventional shielding and

their biological effects are currently very

poorly understood. From theoretical considerations and preliminary experiments it appears that they may be much more effective in

causing biological damage than other types of

ionizing particles. Thus, though they contribute a small fraction of the total radiation

dose in the reference system, they are of major

concern with regard to the health of space

workers.

116

‘ “ionizing Radiation Risks to Satellite Power Systems [SPS)

Workers, LBL-9866, November 1980, advance copy

1“M R White, Environmental Assessment for the Satellite

Power System, Non-Microwave Health and Ecological Effects,

DOE, in press (1981)

Estimates of the radiation dose for exposed

SPS space workers are uncertain. Few measurements have been made of the radiation fIux in

GEO .

117 It is also difficult to quantify the radiation levels at any one time because solar

storms that significantly increase the levels are

currently impossible to predict. Moreover,

there is considerable controversy over the

models that are used to estimate the amount

of energy absorbed in the human body as well

as the biological consequences of the absorbed radiation.118 The most significant longterm effect of ionizing radiation is cancer.

Cancer risk depends on a number of factors including the total I-fetime dose-equivalent;

dose rate; duration of exposure; and the age,

sex, and susceptibiIity of the expose d

person. 9

DOE has estimated that space workers for

the SPS reference design (which includes modest shielding— 3 g/cm2 aluminum for habitat

and work stations and 20 to 30 g/cm2 for the

storm cellar, used during solar particle events)

would receive 40 reins per 90-day tour or 400

reins for the planned 10 tours. 120 This estimate

could be inaccurate (probably too high) by a

factor of 5 or 10.2’ However, the biological impacts could actually be higher than this dose

wouId indicate if HZE bioeffects are taken into

account and/or a solar particle event occurs. I n

spite of the large uncertainties, it is almost certain that reference system exposure would ex -

ceed current Iimits for radiation workers as

recommended by the National Council on Radiation Protection and the International Commission on Radiological Protection.122 For

comparison, the general popuIation receives

about 0.1 rem/year on the average;123 occupa-

‘ 7M~rgaret R White, Lawrence Berkeley Laboratory, privat e

communlcatlon, Feb 12, 1981

‘‘ “Program Assessment Report, Statement of Findings, op. c It

‘ “1 1 Lyman, “Hazards to Workers From Ionizing Radiation

In the S PS E nvlronment, ” in The Final Proceeding of the Solar

Power $ate//ite Program Review, Apr 22-25, 1980, DOE/NASA

report No Conf -800491, July 1980

‘J{)lonlzlng Radiation Risks to Sate//lte Power .Systems (SPS)

WorLer>r op clt

‘” Program Assessment Report, Statement of Findings, op clt

‘‘Zlbld

‘‘ ‘Committee on the Blologlcal Effects of Ionlzlng Radiation,

The F f fects on Populations of Exposure to Low Leve/s of Ionizing

Racflat/on (BE/R ///), National Academy of Sciences, 1980,

tvpesc rlpt edltlon
224 ● Solar Power Satellites

tional exposure limits (for blood terming

organs) are 3 reins for 90 days and 5 reins over

1 year;

1 2 4

and the NAS maximum recommended exposure limit (for bone marrow) for

astronauts is 35 reins for 90 days, 75 reins over

l-year period and 400 reins for Iife.125 If space

worker careers were 5 years, with 90 days in

space alternated with 90 days on Earth, it

would be expected that for each 10,00 0

workers in space, between 320 to 2,000 additional cancer deaths in excess of normal cancer mortality would occur. 126 An issue critical

to SPS design and economics is whether the

radiation standards developed for astronauts

should be applied to SPS workers.127

Risks could be reduced in a number of ways.

For example, the time per tour and the number

of tours per worker could be decreased. Robots and teleoperation could be used to reduce the number of people required in space.

It is also essential that accurate, quick and

rugged dosimeters be developed that monitor

the real-time radiation flux and energy levels

to which each individual is exposed.

128 i n -

struments would also have to be developed to

warn personnel in GEO of solar storms or other

unforeseen high radiation events so that they

can move to shelters. Considerable improvements in dosimeter technology are needed

since present devices are not very accurate

and take a long time to display radiation

levels. Shielding is also crucial Some of the

’

24W Schimmerling and S Curtis (eds ), Workshop on the Radiation Environment of the Satellite Power System (SPS], Sept 15,

1978, DOE, Conf -7809164, December 1979

1251b;d

‘2’Whke, Environment/ Assessment for the Sate//ite power

System, Non-Microwave Health and Ecological Effects, op cit

‘*’Program Assessment Report, Statement of Findings, op cit

‘

2

’ Environmental Assessment for the Satellite Power System

Concept Development and Evacuation Program, op clt

risks associated with the reference system

couId be reduced with additional or innovative

shielding. Analysis is needed to determine if

better shielding techniques can be devised that

would not incur a greater weight or cost penalty. Studies are also needed to examine to

what extent additional shielding mass will incrementally reduce risks of exposure to most

radiation (because secondary radiation can be

produced as the thickness is increased),129 or if

shielding materials can be developed to stop

HZE particles.

DOE has concluded that as presently designed, the reference system construction

scenario is unacceptable. 130 Risks could be

reduced if personnel spent more time in LEO.

More study is required to improve the current

assessment and to explore the impacts on the

system Cost and feasibility of modifications of

the reference system in order to minimize ionizing radiation hazards.

I n sum, research priorities include:

●

●

●

●

●

measurements of radiation flux in CEO.

This can be done with CEO satellites; the

space shuttle and space operations center

wilI provide data on LEO;

study of the bioeffects of HZE particles;

continued study of radiation bioeffects

and refinement of models;

improvement in dosimetry techniques and

shielding technology; and

for SPS, improved analysis of exposure

risk, and shielding techniques, consideration of exposure limits, and assessment of

the viability of workers in space: tradeoffs

between human health, system feasibility,

and economics.

12“ProgrJm Assessment Report, Statement of Findings, op cit

‘ ‘“l bld
Chapter 9

INSTITUTIONAL ISSUES
Contents

Financing, Ownership, and Control .

Space and Energy Sectors . . . .

Government-Private Sector Relat

Phases of SPS Development.

Possible Models . . . . . . . . . .

ons

. .

The Implications for the Utility Industry

Introductio n

The Utilities’ Planning Process .

Page

. . . . . . . . . . . . . . . . . 227

. . . . . . . . . . . . . . . . . . . 227

.., . . . . . . . . . 227

. . . . . . . . . . 229

. . . . . .23 0

. . . . . . 23.5

. . . 235

. . . . . . . 235

Engineering Implications of the SPS for the Utilities Grid . . . 239

Regulatory Implications of SPS . . . . . . . . 243

General Implications for the SPS . . . . 245

Issues Arising in the Public Arena

. . .

. . . ... 247

The SPS Debate . . . . . . . . 247

Siting . . . . . . . . . . . . . . . . . . . . . . 258

TABLES

Table No. Page

50. Characteristics of the SPS System . . . . . . . . . . . . . . . . . . . . 236

51. Major Grid Contingencies . . .237

52. Potential for Power Variations From the Reference System SPS . . . .241

53. Major Issues Arising in SPS Debate . . . . . . . . . . . . . . . . . . . . . . . 250

54. Potential Benefits and Drawbacks of SPS “Technical Options . . . 259

FIG U RE

Figure No, Page

44. Phases of R&D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
Chapter 9

INSTITUTIONAL ISSUES

FINANCING, OWNERSHIP, AND CONTROL

The questions of who would finance, own,

and control a solar power satelIite (SPS), and to

what extent, are interrelated. As a project that

would involve the Nation’s space and energy

sectors, as well as several Government agencies, there are numerous issues to be considered regarding the proper allocation of risks

and responsibilities. The following discussion

will examine: 1 ) current policy and structure of

the space and energy sectors; 2) the relation

between Government and private-sector activities; 3) the importance of distinguishing between the different phases of SPS development and operation; and 4) possible historical

and hypothetical models for an SPS project.

Space and Energy Sectors

Space

I n the United States, space capabilities have

been primarily instigated and funded by the

Federal Government (with much of the actual

development and construction done by private

firms under contract to the National Aeronautics and Space Administration (NASA)).

Launchers, launch facilities, and tracking networks are currently Government monopolies

that may be leased to private companies,

Government agencies, or foreign countries for

specified purposes. Only certain payloads are

built and owned by nongovernmental bodies.

Within the Government, NASA is responsible

for R&D of civilian space-systems that, when

development is completed and the operational

stage begins, are turned over to another part of

Government or to the private sector. Scientific

missions, such as deep-space probes, are run

by NASA, as are launch facilities such as Cape

Canaveral. Military and intelligence operations are largely separate even in the R&D

phases, with control exercised by the Department of Defense (DOD) or specific intelligence

agencies.

Energy

EIectricity is provided by public and private

utilities, which are regional monopolies regulated by State authorities. R&D and construction of generating equipment—turbines, nuclear reactors, switching gear— is done by private firms, who sell to utilities. The utilities

operate and maintain equipment, build transmission lines, and market electricity to endusers Due to severe capital constraints and a

lack of expertise in space operations, utilities

are unlikely to own and operate SPS in the way

they currently do with other types of powerplants, though they may well be responsible

for the ground-receivers. In the case of SPS,

there is a question as to who would carry out

these various activities,

Although energy production in the United

States has traditionally been handled in a

decentralized manner by private industry, increased sensitivity to the importance of energy

issues since the 1973 oil embargo has led to

various attempts at formulating a national

energy policy, centered in the newly created

Department of Energy (DOE). DOE’s scope and

responsibilities in areas such as basic research

and engineering have yet to be determined;

funding is being provided for projects in

photovoltaics, conservation, nuclear power,

synfuels, and other areas. DOE can be expected to have a prime role in any SPS project.

Government-Private Sector Relations

What would be the degree of Federal involvement with the SPS at different stages,

such as R&D, construction, and operation; and

in different areas, especially financing, transportation and transmission, and marketing?

The arguments for Federal involvement center around fears that the private sector will not

be able to undertake an SPS project, because

227
228 ● Solar Power Satellites

of the very high costs and risks, and the long

and uncertain payback period. There is also

concern that private-sector development, even

if economically feasible, might be detrimental

because of monopoly by a single firm or consortium, and environmental and international

policy considerations requiring public control.

Cost estimates for different SPS scenarios

are very imprecise; the most comprehensive

estimates have been done by NASA for the

reference design and calI for a total investment of $102 billion (1977 dollars) over 22

years for construction of the first 5-GW SPS,

i.e., before any return on investment (see ch. 5).

The key questions are whether the private sector can or would raise these amounts of

capital, and how investment cost s and

management responsibilities might be shared

between Government and industry.

Though the reference figures are highly tentative, the general magnitude of the project

and its division into discrete stages are likely

to be similar regardless of what design is used.

None of the alternatives has been examined in

nearly the detail of the reference design, largely because the technologies are less well-developed. The following discussion will focus on

reference figures but should be applicable to

any SPS system of similar magnitude.

Difficulties With Private Involvement

A total investment of $40 billion to $100

billion over 22 years–with additional much

larger investments to build a complete system —would be unprecedented for private-sector financing of a single project.

Private capital can be raised by borrowing,

issuing bonds or stocks for sale to the public,

or from profits. Especially in the first years,

borrowed funds would be available, if at all,

only at prohibitively high interest rates. Stocks

and bonds would be unlikely to attract large

investors when profitabiIity Iies some 30 years

in the future. Both institutional investors and

large corporations allocate only a small proportion of their funds for high-risk long-term

projects; in some cases, such as pension funds,

there are legal limitations on high-risk investments. Uncertainty, whether technical, political, or economic wilI deter potential investors.

The incentives required to spur any private

interest would in themselves involve drawbacks. A company taking a major risk on SPS

would expect to be compensated by exclusive

patents and other guarantees, in effect with a

monopoly. Government regulation would have

to take risks into account by allowing a very

high rate of return, i.e., allowing the owners to

charge high rates for SPS electricity. A private

monopoly charging above-average prices

could prove to be politically embarrassing.

An SPS system will require a great deal of

political support both locally, nationally, and

internationally: land-use conflicts, monopoly

considerations, environmental standards, tax

incentives, and radio frequency allocations are

a few of the political issues that SPS will need

to confront. Private development and ownership may be seen as leading to an excessive

concentration of power outside effective public control

Difficulties With Federal Involvement

Any large long-term project, public or private, dealing with advanced technology may

suffer from financial and management problems: lack of coordination between parts of

the program; inadequate supervision of contractors; financial and production bottlenecks

in specific areas that delay other parts of the

program; inaccurate initial estimates of costs

and completion times, and so on. However,

Government programs often have special constraints that need to be taken into account.

Without a profit motive and the discipline of

responsibility to owners and stockholders,

there is less incentive to reduce costs. Civil

service regulations can interfere with hiring

and firing and limit salary ranges, decreasing

flexibility and making it difficult to retain personnel Annual Government funding produces

uncertainties and leaves programs vulnerable

to political pressures and pork-barrel compromises. Government-funded R&D in the public domain requires special supervision, since

without the incentive of exclusive rights to

patents and processes, firms doing research
Ch. 9—institutional Issues ● 229

may tend to inflate costs and draw out delivery

scheduIes. 1 Any extensive Government funding

could divert funds from other space, energy,

and R&D programs, whose backers might ask

for compensation.

Explicit Federal involvement may increase

the probability of military participation in

some or all SPS activities, complicating most

forms of international cooperation and

possibly leading to detrimental changes in the

SPS design or operating characteristics.

Finally, a federally financed or owned SPS

would increase centralized control over an important sector of the economy and would lead

to greater politicization of America’s energy

industry.

Phases of SPS Development

Federal v. private investment is not an

either/or proposition. I n general, Federal involvement would be necessary in the early

stages, and become increasingly less so,

assuming the system remains technically and

financially feasible, as the project becomes

operational. The basic problem is how to differentiate between the various and overlapping stages and ensure adequate management

and continuity throughout.

SPS development can be divided into successive stages (as described in ch. 5): research,

engineering, demonstration, and so on. Federal

financing and management of the research

and engineering phases might turn into a combined Federal-private program as more directly

commercial phases were undertaken. The

question is at what point and to what degree

private investors will be willing to enter the

project. On the one hand, investors would

prefer to see as much as possible paid for by

the Government; but early investors would

have an advantage in setting program priorities and establishing a dominant position.

Involvement of owners and operators at the

earliest possible stages would help to ensure

that the completed system is suited for comI Mark Cersovltz, “Report on Certain E conornlc Aspects of the

SPS Energy Program, ” OTA ( ontrdf I No ()} 3-26700, 1980, pp

1719

mercial operation, that internal procedures

and structure are appropriate to private ownership, and that the transition from development

to operation proceeds smoothly.

The SPS would consist of a number of distinct systems, each of which must be developed separately and simultaneously: e.g.,

transportation, energy conversion and transmission, orbital construction, and ground stations launchers and solar cells, for instance,

may be useful and profitable regardless of

whether SPS is built or not. Should their

development be charged to SPS? If so, their

use and sale might help to offset the risks of

the program as a whole; on the other hand,

their development adds considerably to the

SPS cost. It can be argued that public funding

should be reserved for those parts of the project that private investors will not handle and

that segments with near-term commercial applications should be left to the private sector.

As in any complex program, there is the question of internal apportionment of risks and

benefits. Successful items can help to subsidize less profitable projects, provided funds

are transferable from one division to another,

allowing for risky high-return investments, but

also for Edsels.

In the case of SPS it is essential that each

component be developed on time and to the

proper specifications for the system as a whole

to function. Management must be given sufficient authority to produce appropriate products., even if particuIar divisions suffer; say, if

SPS solar cell designs are not optimal for

ground-based users. Major investors in a privately funded SPS wiII have their own particular interest–aerospace companies in launchers, electronics firms in microwave hardware,

utilities in delivered power — that could compromise the project’s overall goals. Government supervision, whether by partial ownership, reguIatory oversight, or appointment of

d i rectors, may mitigate certain confIicts but is

no guarantee of smooth saiIing. Federal concern for a broadly conceived public interest

may be affected by a desire for continued control and supervision, or by the interests of particuIar agencies. For instance, DOD may place
230 ● Solar Power Satellites

emphasis on booster and LEO to CEO transport development for its use (see ch. 7),

perhaps affecting launcher design or the allocation of program funds. NASA may wish to

emphasize and prolong the R&D phase. Annual budget review may increase costs by creating uncertainty and requiring project managers to spend large amounts of time drawing

up and justifying annual budgets.

Possible Models

Perhaps the best way to further examine

possible financing and management scenarios

is through historical and hypothetical models

that might be applicable to SPS. In each instance there are several questions to be asked:

1) Is it complete: can this model support an

SPS program from start to finish, or is it applicable only to certain phases or components?

2) How are risks apportioned: who pays, and

who reaps the benefits of a successful project?

3] How efficient and flexible is it: can it adapt

to changing economic and technical circumstances, and can it attract support from a

variety of sources, particularly foreign investors?

Historical Models

NASA

NASA is an independent Government

agency with a general mandate to engage in

R&D and testing and to conduct launches for

civilian space activities. Although NASA has in

the past centered its efforts on high-visibility

manned projects, such as Apollo and the

Space Shuttle, it has also conducted major

programs in telecommunications, remotesensing, and the sciences, such as the Viking

and Voyager interplanetary probes.

NASA is funded by general tax revenues appropriated annually by Congress. NASA funds

are overwhelmingly—90 to 95 percent— spent

on outside contracts with private firms, research centers, and other Government agencies, foreign as well as domestic. NASA itself

helps to set priorities and policies, oversees

and coordinates contractor performance, and

operates specific faciIities (on a cost-reimbursable basis) for research and launches.

●

●

Advantages. – NASA is already in place, with

22 years of experience. It has well-established relationships with private contractors,

other parts of the Government, and foreign.

companies and Government agencies. It has

the technical and administrative expertise to

evaluate most of the major components of

the SPS, many of which— interorbit transfer

vehicles, assembly and construction facilities — are part of current NASA plans.

Disadvantages. –Annual funding for NASA

projects creates difficulties in implementing

long-term plans that are likely to go in and

out of political favor. It also hampers

agreements with foreign firms and agencies,

that have had problems in the past when

NASA budget cuts have forced cancellation

of joint programs. Legislative changes to

permit ongoing funding would greatly improve NASA’s position.

NASA’s emphasis on R&D and prototype

development (NASA’s ability to participate

in commercial ventures is unclear and subject to restrictions) could create problems in

developing a commercial product such as

SPS; NASA might have to relinquish control

after the demonstration phase. There is

often reluctance to complete R&D phases,

since completion means loss of the project.

Coordination with eventual users and owners may be underemphasized. Amending

NASA’s charter to allow for beginning-toend development and operation would alleviate this problem, but might be harmful to

the agency’s R&D mission.

The broad scope of NASA activities has

meant that, within and without the agency,

there have been conflicts over the relative

priority of scientific v. applications, or

manned v. unmanned missions. The SPS

could be criticized for diverting funds and

attention from competing programs; intraagency squabbling might interfere with the

project. Excessive concentration on SPS

could prevent NASA from accomplishing

other tasks, although many aspects of SPS
Ch. 9—Institutional Issues . 231

development would be applicable to other

space activities.

Funding all, or even a large part, of the

SPS through general tax revenues would produce strong pressure for continued Government control. Since the risks are borne, involuntarily, by the general public, justification in the form of visible public benefits

may have to be provided. These benefits

couId take the form of electricity-rate reductions, tax-reductions, or other types of

returns. Turning SPS or SPS technology over

to private profitmaking firms may be unacceptable. Such a prospect could discourage

private interest; this difficulty is common to

all publicly financed ventures.

TENNESSEE VALLEY AUTHORITY (TVA)

TVA, the Nation’s largest utility, was established in 1933 to provide power for a region

that commercial utilities were not willing to

develop. Until 1959, TVA received annual

Federal appropriations; since then it has raised

capital by issuing bonds, the amount of which

is subject to congressional approval, as well as

by charging customers for its services. At that

time, TVA was forbidden from expanding its

service area, in order to avoid competition

with private utilities. In 1978 TVA’s borrowing

authority was raised to $30 billion. 2 A TVAtype independent authority, initially financed

by tax revenues and authorized at some point

to issue self-backed bonds, could be a possible

model for SPS development and operation.

Ž Advantages. — Initial Federal financing

would allow for pursuit of R&D and prototype development. Adoption of TVA practices, such as the absence of civil service requirements, would free the authority from

certain Government inefficiencies. Issuing

bonds would subject the issuer to the financial judgments of investors and make the

risks of the project more palatable, since

much of the investment would be voluntary

rather than by congressional or executive

decision. The concentration of a newly

established authority on a single-project

wouId avoid the internal conflicts inherent

“’increasing the TVA Bond Celling, ” hearings before Senate

Environment and Publlc Works Committee, Feb 23, 1979

in having it undertaken by an established

agency.

● Disadvantages. — It is not clear at what point

private financing would become available

on a large scale, and hence how much must

be spent out of general taxes. The larger the

public part of the investment, the more

likely are the public-interest problems

outlined previously.

Financing through bonds does not provide

for the type of accountability available

through congressional appropriation, or

through public ownership via the stock market Specific arrangements for public oversight, given the monopoly position of such

an entity, would have to be made. Ownership of patents and products generated by

public investment would have to be clarified, given the possibility of competition between private firms and the authority in the

latter stages of development and operation.

HIGHWAY TRUST FUND

Since 1956 the Federal Government has

spent over $7.5 bill ion (in current dollars) to

finance the Interstate Highway System and a

number of other road and highway programs.

The money for these investments has been

channeled through the Highway Trust Fund,

which receives revenue from taxes on gasoline

and diesel fuels, on heavy trucks, and other

sources. These funds are not spent by the

Federal Government, but apportioned to the

States to pay for their share of highway

systems.

The rationale for Federal financing was that

an improved road-system would aid the Nation’s defenses, as well as improve commerce

by decreasing transportation costs. The system

was planned on a national scale, but takes advantage of existing State highway departments

to implement the proposed network. No central construction or maintenance firm was

needed 3

The distinctive feature of the system is its

use of specific taxes on a commodity directly

related to the project. Through the tax on gaso-

‘Porter (’ wheeler, Hjghwa y A \\[jtance Programs A Ffl\torlca/

~~erfpf,( ~lve, Congre$slonal Buclget Of flee, FebrUaw 1978
232 ● Solar Power Satellites

line and diesel fuel, transport users have contributed in proportion to their total transportation expenditure. An additional tax on

heavy commercial trucks has ensured that

large users, who were responsible for a high

proportion of maintenance costs, would contribute appropriately. Unlike tolls or direct

fees for highway usage, revenue could be collected before the roads themselves were completed. An analogous tax to finance a fund for

SPS might be levied on current domestic and

commercial electricity consumption (though

from a strictly financial point of view the tax

need not be directly related to energy congumption. )

●

●

Advantages. —The use of a designated tax

provides more assured and predictable funding than general revenue taxes that need to

be reallocated on a yearly basis. By taxing

electricity consumption the costs would be

borne by the future beneficiaries of SPS. If

desired, taxes on other forms of energy

could also be imposed; all energy taxes

would have the added benefit of encouraging conservation. As private investment was

found, the tax could be reduced, or revenues

couId be spent elsewhere.

The size of the tax, if levied on electricity

alone, would not have to be large to generate significant revenue. A tax of 2 mills/kWh

would produce over $4 billion per year (at

current consumption rates) while raising

consumer costs by less than 5 percent.4

Disadvantages. — A tax on electricity may

cause consumers to switch to other forms of

energy, harming utilities Higher electricity

costs will inflate prices of electricityintensive products, such as alum inure.

The organizational framework to manage

the SPS will have the same difficulties as

other Government agencies, especialIy in

handling the transition to private ownership.

U.S. SYNTHETIC FUELS CORP.

The Synfuels Corp. was established in June

1980 with a specific mandate to produce the

equivalent of 2 million barrels per day of crude

‘Peter Vajk, SPS FInancIa/, Mandgernent 5( en,]rlo~, DO F contract No EC77-C-01 -4024, October 1978, p ;6

oil by 1992. The corporation is instructed to do

so by, in decreasing order of preference: 1)

price guarantees, purchase agreements, or

loan guarantees; 2) loans; 3) joint ventures. The

corporation’s goal is to faciIitate private-sector

synfuel production, and to produce synfuels itselt only as a last resort. Initial funding was set

at $20 billion, with total funding of up to $88

billion envisioned. Funds are to be provided

from the windfall-profits tax on domestically

produced oil. 5

A possible SPS corporation would resemble

the Synfuels Corp. in being a high-cost energy

production plan with a specific goal and timetable It would differ in that it would involve

creating a single firm rather than funding numerous private enterprises.

●

●

Advantages. — The Synfuels Corp. has the advantage of a discrete goal and timetable,

with maximum flexibility as to achievement.

The etmphasis on price and loan guarantees

to encourage rather than replace conventional financing arrangements should reduce the cost, assureing projects are successful. Direct Government control will be

avolded, unless no private ventures whatever are forthcoming.

Disadvantages. – It is far too early to tell

whether the Synfuels Corp. will accomplish

Its goal, or wiII do so without exorbitant

costs Critics fear that an indiscriminatory

‘shotgun“ approach may result in funding

numerous uncompetitive ventures, in the

hope of finding one that works; while the

revenue taken from the oil companies in

taxes may prevent the development of additional fuel sources. The promise of “easy”

Government money and soft loans may discourage efficient financial and managerial

practices.

While the Synfuels Corp. can pick and

choose from a number of relatively welldeveloped and predictable projects, the SPS

Corp would have to generate its own

organization. The SPS Corp. couId not, especially at first, simply be a channel for funding to private firms, or for loan guarantees.

— -- —----

~ n(’r~~ $~)( (/r/[y A et, Publ IC Law %9,24, 96th Cong , j une )(),

19H() ill [{
Ch. 9—institutional Issues ● 233

COMSAT

Comsat was founded in 1962 as a federally

chartered corporation to establish and run

satellite communications (see ch. 7). Comsat

did not receive direct Federal funding, but was

given the fruits of extensive and continuing

NASA research on telecommunications satellites, 6 as well as the right to use NASA launch

services on a reimbursable basis (which does

not reflect R&D costs). The Government retained a measure of control through Comsat’s

operating charter and by appointing board

members, who were initialIy divided between

Government, communications common carriers, and private investors. Capital was raised

by issuing stock, which from the outset was

well-received by investors. As of 1979, Comsat

stock was held overwhelmingly by noncommon carriers; 3 of 15 Board members were

Presidential appointees, the rest being elected

by stockholders.

● Advantages. — A Comsat-styled SPS corporation would be independent of direct Government control and free to operate as a private, profitmaking corporation. Government

supervision would be provided without the

need for onerous restrictions. Comsat has

been highly successful internationally via its

participation in lntelsat, and a “Solarsat”

corporation might find it easier to engage in

international activities than would a Government agency. Such an organization could

inherit the results of Government-financed

R&D and engineering with less of a political

outcry than if control were to be turned over

to established private firms such as aerospace or oil companies; Comsat was established in large part to prevent AT&T from

gaining a satelIite communications monopoly.

● Disadvantages. — Issuing common stock

would not suffice to raise capital for the

early development stages. The transition

from Government to private funding would

‘NASA communications research was phased out under the

Nixon admlnlstratlon, which looked to Comsat and the privat e

sector to maintain U S preem Inence In commun Icatlon satel I tte

technolog y However, In 1978 the Carter admlnl~tratlon

reinstated NASA’s leading role In communlcatlon> R&D, largely

to offset foreign government R&D effortj

83-316 0 - 81 - 16

have many of the difficulties already mentioned.

PRIVATE JOINT-VENTURES

A private SPS project could be undertaken

either by an established firm, a new company,

or a joint-venture of existing companies and

financial institutions. For the reasons mentioned (high cost, uncertainty, long period

before payback, and too many eggs in one basket) no single firm, whether new or established,

iS Iikely to undertake SPS development unaided

A joint-venture or consortium is formed

when a single project or enterprise is of interest to several parties, no one of which is

wilIing to finance or manage it on its own, as

with the Alaskan pipeline. Or, companies may

be legally prevented from exercising sole ownership for antitrust reasons, while a single

system may be technically desirable. For instance, the Federal Communications Commission (FCC) required Comsat and IBM to add a

third partner (Aetna Insurance) when forming

Satellite Business Systems (SBS). In any consortium, partners are Iikely to have a particuIar

interest in the consortium’s success above and

beyond immediate profitability. In SBS’s case,

IBM Corp. and Aetna intend to be major

customers of the system, and IBM Corp. will

suppIy operating equipment. 7

● Advantages. — Potential major partners in an

SPS consortium would be: aerospace companies, oil/energy firms (including possible

emergent industries in photovoltaics, synfuels, or other energy sources); and electric

utiIities. A consortium that could draw on

the resources of firms in these major industries would find it easier to borrow money,

selI stocks and bonds, and use profits for

SPS investment. According to most estimates, the utility industry alone will be

spending hundreds of bilIions of dolIars over

the next 30 years to replace old generators

and build new capacity; an SPS project

wouId not constitute an unmanageable proportion of total industry investment,

—.—

( ourt Upholds SPS, ” Avlatlon Week and Space Technology,

Vldr 1 ( I 1980, p 22
234 ● Solar Power Satellites

● Disadvantages. – However, there would still

be difficulties in funding the initial phases.

While aerospace and electronics firms

wouId begin to benefit relatively early in the

project, oil/energy companies and utilities

(that have the bulk of the resources) will see

returns only towards the end. utilities in particular, as part of a publically regulated industry, will find it difficult to set rates so as

to raise funds for R&D or speculative purposes, as opposed to purchase of more established technologies. For instance, the $2

billion Great Plains coal gasification project

was to be financed by a surcharge on gas

rates charged by consortium members. Although DOE approved the rate hikes, customers — such as General Motors—and

State officials protested against being asked

to subsidize synfuels investments.8 The Federal district court then disallowed DOE’s action, effectively blocking the project.

Consortia are more likely to arise in the investment and operation phases, when individual members’ interests are more clearly

defined, and risks have been reduced. The

very high costs and large size of a full-scale

SPS system, as well as the monopoly dangers

of a system under the control of single company, may make inter- or intra-industry consortia attractive.

Hypothetical Models

In discussing possible SPS financing scenarios, some writers have proposed completely

novel methods with no historical precedent.

Foremost among them are the Taxpayer Stock

Corp., a new form of Government financing;

and a private approach, the staging company.9

TAXPAYER STOCK CORP.

Under this method, taxpayers would receive

shares in a public corporation, financed by

general tax revenues, in proportion to the percent of taxes used to finance SPS. Shareholders

could then trade their shares on the market, as

with any other corporation. Those who did not

‘Robert D Hershey, “Gasification Plant Rising Amid Many

Snags, ” New York Times, Nov 17, 1980, p 1

‘For further discussion see Vajk, op clt , pp 32-40

wish to support SPS could sell their stock for

immediate returns.

Although such a scenario has the advantage

of diffusing SPS ownership, it is difficult to see

how SPS shares would retain their full value on

the market; if they did, funding via taxes would

not have been necessary in the first place.

Shareholders would instead be left with devalued pieces of paper, unless they are purchased

by the Government —with tax dollars — to

maintain a reasonable price. This would

amount to a straightforward Government subsidy.

STAGING COMPANY

The staging company is essentially a bootstrap operation whereby sufficient revenues

are generated during the R&D phase to attract

further capital. The firm would invest its initial

funds in existing aerospace and high technology companies, gaining patent rights and new

technology—via joint ventures—as well as

conventional investment returns. The success

of the company’s first investments, and its increasing expertise, would attract further

speculative investors; the staging company is

in effect a mutual fund. Eventually, the company would begin to finance SPS R&D directly,

concentrating on those aspects with near-term

returns. At some point conventional financing

would become available for the investment

and operation phases.

Such an approach is unlikely, unless its first

investments turn out to be in budding Xeroxes

or IBMs, to raise the $33 billion estimated to

be necessary for the reference design R&D and

prototype phases. In 1978 Christian Basler

established International Satellite Industries,

Inc., to test his concept; it failed when neither

New York nor California would allow ISI stock

to be sold. 10

Conclusions

It is clear from the review of possible models

that there are many ways to finance the latter

stages of a successful SPS program, but that

‘

(

’(’ onversatlon with Stephen Cheston, President, Institute for

the \oclal \clence Study of Space, December 1980
Ch. 9—lnstitutiona/issues . 235

the initial phases would in all likelihood have

to depend on some sort of Federal funding.

Some combination of the suggested methods

may prove attractive.

In establishing an SPS organization, attention should be paid to several factors. First,

there should be provisions for stopping the

project if it becomes unfeasible. Large initial

investments wiII create considerable momentum, which may cause wasteful development

to continue unless authority is given to terminate. This is especially true for Government

enterprises.

“Gersovitz, p 36

Second, at all phases careful attention must

be given to public policy concerns: environmental protection, regional interests, and military involvement. Private companies must not

think SPS can be developed in secrecy or without reference to a wide public environment

(see ch 8, Issues Arising in the Public Arena).

Third, early and continuous efforts should

be made to involve and inform potential international partners to attract investment aid,

forestall competition, and ensure that the

global market for SPS is kept in mind when

technical and managerial decisions are made.

A narrow focus on domestic concerns, by Government or industry, may jeopardize SPS unnecessarily. (see ch. 7, International Implications).

THE IMPLICATIONS FOR THE UTILITY INDUSTRY

Introduction

The interest of the utilities in the SPS would

depend on technology related factors such as

stability and reliability, as well as those more

directly related to the economics of electricity

generation and distribution (i. e., siting, capital

investment and Government regulation). Each

of these factors would require more study as

more is learned about the various SPS alternatives. From what is now known, it appears that

the technical barriers to integrating SPS into

the utility grid are solveable, particularly if the

units of SPS generated power are of the order

of 1,000 MW or less. It is also apparent that for

the utilities to develop sufficient confidence in

SPS, one or more units would have to be tested

over time.

More troublesome are the economic risks of

SPS. When considering adding a new pIant,

utilities must plan far ahead of actual system

integration for the associated transmission

lines and other generating capacity (i.e., intermediate or peaking plants to supplement

the baseload powerplants). Failure of the SPS

to meet expected implementation deadlines

would result in severe economic loss for the

utiIity. The need for extensive trials and testing

of a new plant render it highly unlikely that the

SPS could become part of utility grids until

several years after a commercial prototype

were built. Although SPS could force some regulatory changes, there seem to be no strong

regulatory barriers to implementing SPS.

Table 50 summarizes the projected characteristics of the SPS that would be of interest to

the electrical utilities.

The Utilities’ Planning Process

The Current Situation

Because of the recent rapid rise of all energy

costs and subsequent efforts to conserve, the

utilities find themselves in an uncertain position for the future. In the past, the utilities experienced fairly steady, high peakload growth

rates, resulting in a correspondingly high rate

of growth (7 percent) of generating capacity, a

rate that leads to a doubling of capacity every

10 years. Recently, however, average peakload

growth has fallen sharply. Lower economic

growth rates and price-induced conservation

efforts have had a strong effect on consumption I n response, the average growth of installed generating capacity has also fallen. The
236 ● Solar Power Satellites

Table 50.—Characteristics of the SPS Systems

The reference

System characteristics system ”

Delivered power from each

satellite (at the busbar )

Total system of. . . . . .. .

Implementation rate ... .. .

Start of deployment. . . . . . .

Lifetime of each satellit e

Transmission frequency ... ,

Designed capacity factor . ,

Rectenna size. . . . ... .. .

Terrestrial conversion mode .

Major potential causes of

interruption .

5,000 MW

300 GW

2 per year for

30 years

A.D. 2000

30 years

2.45 gigahertz

(i.e , microwave)

90 percent

10 km x 13 km at

35° Iat. plus 1 km

buffer

Microwave dipole

Solid-state sandwich

design ”

1,500 MW

Not projected —

2010-2020

(estimate)

30 years

2.45 gigahertz

90 percent

6.5 x 5.5kw at 35° Iat.

plus 1 km buffer

Microwave dipole

Laser system”

500 MW

Not projected

—

2010-2020

(estimate)

30 years

10 microns (infrared)

70-80 percent

36 meter diameter

Thermal conversion

Mirror system

(baseline SOLARES)15

135 GW (10 GW

possible)

810 GW over 6

7

2010-2020 (estimate)

?

Reflected sunlight —

I.e., continuous

spectrum

?

39-km diameter

Thermal, photovoltaic

antenna-rectifier and antenna-rectifier and conversio n

inverters inverters

Maintenance, Maintenance, ecilpses During any thick cloud

Of SatelIite? (max 2 1⁄2 h r

During any thick cloud

satelIite eclipses cover, maintenance maintenanc e

(max. 21/2 hr

near equinoxes)

near equinoxes)

1

“’Satellite Power System Concept Development and Evaluation Program Reference System Report DOE report No

DOE/E R-0023, October, 1978

13G. M. Hanley, et al , “Satellite Power Systems (SPS) Concept

Definition Study, ” First Performance Review, Rockwell International Report No SSD79-0163, NASA MSFC contract No

NAS8-32475, Oct. 10, 1979

14W. S. Jones, L L Morgan, J. B. Forsyth, and J P Skratt,

“Laser Power Conversion System Analysis: Final Report, Vol. I l,”

SOURCE Off Ice of Technology Assessment

U.S. total of installed electrical generating

capacity in 1978 and 1979 rose by an average

rate of 3.1 and 3.2 percent respectively, rates

that cause a doubling of capacity every 22

years. Growth rates in some sections of the

country have been zero or negative in the

same time span.

As the high growth rate of electricity demand and subsequent expansion of the utility

industry has subsided, the industry has had to

rethink its posture with respect to adding new

capacity, I n addition to the uncertainties of

future demand, increasing costs for fuel, more

stringent environmental standards, public opposition to nuclear powerplants and technological changes are also affecting the planning

process. What is perhaps of most concern,

however, is the increasing difficulty private

utilities face in raising the large amounts of

capital needed for building new capacity or

replacing old, inefficient plants

In response, the utilities are placing more

emphasis on understanding the interaction be-

(Lockheed Missiles and Space Co , report No LMSC-D67 Mbb,

NA5A report No CR-1 7952 ], contract No NASA ;-211 37, Mar 1 ~,

1979

K W II II I man, W P G I I breath, and S W Bowen, ‘Orbiting

Mirror\ t<)r Terre$trlal E nergv Supply, ” In ‘ Radlatlon F nergv Conver~lon in ~pacej Progre\s In A $tronaut~cj & Aeronauflc\ Serle\,

K W EIII lman (ed ), VOI bl (New York Al AA, July 1978), pp

(>1 ~lo

tween reserve margins, types of capacity, and

reliability requirements. They are also sharply

reducing the amount of new capacity, delaying

Installation of some plants, canceling others,

Although on average the difference between

total capacity and average annual load is

greater than ever before, some industry executives have expressed concern that these

pl,lnned reductions in generating capacity wi II

Ie,ive the United States seriously deficient if

the current trend towards lower growth of

peak demand reverses itself. others, generally

outside the industry, have suggested that increased conservation measures can bring the

need tor new generating capacity to zero or

lets, Ieavlng the industry, on the average, in

the posit ion of simply replacing or refurbishing

outmoded plants

Planning Process

U S generating capacity in 1980 was about

600 glgclwatts. * The peak load that this capaci-

— ——. .—

1 ~ IX< I ,1, i t t (c; w ] or IJOWpr I \ e(\u,1 I ( 01 ,()()() rmegc)w,itt \
Ch. 9—institutional Issues ● 2 3 7

ty is expected to serve is about 410 GW. To

meet this load, the generating capability is

composed of about 10 to 15 percent of peaking units, 20 to 25 percent of intermediate and

60 to 65 percent of baseload generating units.

A planning reserve margin of 20 to 25 percent

above peak demand is required to allow the

utility to continue to serve the customer when

any of the operating units fails and when unusual load peaks occur.

For a given utility system, the reserve is

related directly to the expected reliability of

the total system. Although the exact amount of

reserve needed is currently debated within the

industry, I b the rule of thumb that most utility

systems use to calculate their necessary reserve is that they must have no more than one

generating outage or failure to meet expected

demand in 10 years, a failure that may be as

short as a minute or as long as several hours. I n

practice, this criterion results in some days of

line voltage reductions and a few days of appeals to customers for conservation, but a very

low probability of outage in any one year.

A utility is not simply a set of generating

plants, transmission lines, and transformers. It

is a complicated interactive network in which

individual components affect each other

through an intricate set of feedback loops. A

failure in one part of the system may set off a

failure in another part. Adequate reliability is

ensured by building enough redundancy into

the system to meet most contingencies,

whether from system failure or from unexpected surges in demand.

The amount of redundancy required for a

given system depends heavily on the reliability

of the equipment in the system and the utilities’ experience with them. To calculate the

necessary reserve, the utilities generally use

several methods, the simplest of which, called

the contingency outage reserve criteria, will

serve to illustrate the most important features

of reserve planning.

“A Kaufman, L T Crane, J r , B M Daly, R J Profozich, and

S j Bodily, “Are the Electrlc Utllltles Gold Plated?” committee

print, 96-1 FC 12 Committee on Interstate and Foreign Commerce, United States House of Representatives, 1979

After projecting the peak load requirements

of the system, utility planners add an amount

of generating capacity equal to that which

might be unavailable because of scheduled

maintenance. System reliability will then be

achieved if sufficient excess capacity over and

above this amount is available to cover one or

more of the sorts of contingencies I isted in

table 51.17 This method tends to treat the

system in gross terms and does not generally

allow for important details of a given system

such as the variations of peak load throughout

the year or the percentage of time it will be

t apable of generating given levels of power at

tlifferent seasons. For this, a more sophist i-

( ated analysis would be needed.

Planning for New Technologies

The SPS is one among many new technologies that the utilities are considering in planning for the future. These include regiona/

technologies such as ocean thermal energy

conversion and geothermal; intermediate or

peaking technologies such as wind, solar thermal and solar photovoltaic without storage;

,~nd baseload possibilities such as advanced

coal, breeder reactors and fusion. I n addition,

~ome utilities are considering grid connected

dispersed technologies such as solar thermal,

solar photovoltaics, wind, and fuel cells. Planning for such a mixed bag of technologies is a

complicated and time-consuming process. As

figure 44 illustrates, the time from the initial

conception of a new technology to actual integration into the utilities’ grid can be extremely long– up to 40 years or more. Not only must

utility suppliers develop the components of

the individual technology, they must make it

technological Iy and economical Iy attractive to

‘ Ibl(j

Table 51 .—Major Grid Contingencies

1. Loss of the largest generating unit in the system

2. Loss of the two largest generating units in the system

3. A failure in the largest transmission facility in the system

4. A combination of the above

5. An error of a specific magnitude in load projection

SOURCE A Kaufman, L T Crane, Jr., B. M. Daly, R J. Profozlch, and S. J.

Bodily, “Are the Electrlc Utilitles Gold Plated?” colnmlttee print,

96-IFC 12. Committee on Interstate and Foreign Commerce, United

States House of Representatives, 1979.
238 ● Solar Power Satellites

Figure 44.— Phases of R&D

I — I

1000

V) 100 G

s

10

1

0 10 20 30 40

Years

SOURCE: R L Rudman and C. Starr, 1978 “R&D Plannlng for the Electric Utlllty

Industry, ” In Energy Techrro/ogy v Government I nstltutes, Inc ,

Washington

the utilities and, in addition, develop a large

supportive infrastructure. Thus, the vast bulk

of the time spent in the long chain of technology development is in the phases following

scientific feasibility— newly conceived technologies are not I ikely to fill near-term supply

deficiencies.

Assuming that an engineering demonstration

of a new technology is successfu 1, its ultimate

fate would depend on several factors whose influence can only be seen dimly at the time

when scientific feasibility is proved. Comparative costs are a prime consideration, but

public acceptance, the complexities of the

technology, and the ease with which it can be

integrated into the existing utility infrastructure are also important (see ch. 6). The utilities

use some or all of the following criteria to

judge a new technology: 18

ECONOMIC CRITERIA

● Cost to the User. — Bus bar costs are important but an expensive long-distance transmission and distribution system may price a

technology that is otherwise competitive at

the busbar out of the market. This problem

could apply to any very large, highly central ized faci I ity.

‘“R L Rudman and C Starr, “R&D Plannlng for the Electrlc

Utility Industry,” In f nergy Techrro/ogy V (Washington, D C

Government In$tltute$, I nc , 1 978)

●

●

Reliability. – Plants that are highly capital

intensive must operate at high capacity factors in order to minimize electricity costs.

Thus, numerous forced or unplanned shutdowns for a given plant would make its technology less desirable. In general, a new technology can be expected to sustain a higher

rate of forced or unplanned shutdown than

a more mature one. Current mature nuclear

plants and coal plants with scrubbers sustain

forced outage rates as low as 15 and 19 percent of their total availability respectively.

As the industry gains even more experience,

it wil I probably be able to reduce this rate

even more.

Ease of Maintenance. — It is extremely important to be able to maintain and repair

components of the generating system quickIy and easily. Nuclear and fossil fuel plants

currently experience planned outage rates

of 15 and 10 percent, but utility experts

believe that these rates can be reduced by

several percent. Here again, mature technologies fare better than newer ones. However,

the percentage of maintenance doesn’t tell

the whole story. The timing of the maintenance is also important. If it is possible to

plan maintenance during periods when electricity peak loads are lower, the adverse effect on the utility is thereby reduced.

RESOURCE AVAILABILITY

Here, fossil or other depletable energy

sources wil I suffer in competition with renewable sources such as wind-, solar-, fusion-,

or breeder-generated fissile material. Further,

because the Sun or wind are more available in

some regions of the country than in others, terrestrial renewable technologies wil I vary in

their attractiveness.

SYSTEM CAPABILITY AND FLEXIBILITY

● Control and Operating Characteristics. — The

more stable a power system, the better.

Short-term transient outages must occur

under conditions that allow the utility grid

to accommodate them as a matter of

course.

———

“1 bld
Ch. 9—institutional Issues “ 239

●

●

●

Ability to Tolerate Abnormal Events. –A system that is otherwise acceptable to the

utilities may fail to be adopted because it is

easily disturbed, i.e., small perturbations in

operating mode lead to wide swings of electrical output.

Unit Rating. –Although economies of scale

are very real in generating equipment,

smal Ier capacity units may often be desirable, because they are easier to repair and

replace than the large ones.

Environment/ Issues. — Environmental impacts produce an economic cost that, while

often impossible to specify, have a strong effect on the acceptability of a given technology. I n addition, some technologies may

have environmental side effects that are

unacceptable no matter what price the uti I ity is willing to pay (e. g., the potential effects

of the addition of large amounts of carbon

dioxide to the atmosphere).

LICENSING

“Licensing . . . is currently the largest single

issue facing al I new technologies. ”2° The issues

that will affect the licensing procedure such as

siting, health and safety, and environmental

concerns must be identified and reckoned with

early in the development of the technology.

They also have a direct effect on the cost of a

technology.

Once a generating technology has proven its

commercial feasibility, it generally takes

another 20 years or so for it to be used

significantly. The complexity of the technology, institutional barriers, market growth

(housing, industry, etc. ) market initiative

(dispersed v. central use), and system size will

all have their effects on the rate at which a

given technology will penetrate the total utility market.

Engineering Implications of the SPS

for the Utilities Grid

The SPS would make numerous special

demands on the utility grids. Some are related

to the fact that the primary generator or col-

‘“l bid

Iector would be based in space. Others are

characteristic of all large-scale baseload

technologies. In this section, we will proceed

through each technology, citing the most important effects each alternative will have on

the utilities.

The Reference System

● 5,000-M W Capacity. – Because of the grid

reliability requirements, the large size of the

reference system plant would limit the number of individual utilities or utilities’ systems

that could accommodate it. As a rule of

thumb, a utility generally will not purchase a

single unit that ~wou Id constitute more than

10 to 15 percent of the utility’s total

generating capacity. ” In other words, a

single plant must be no more than one-half

of the system’s total reserve capacity of 20

to 25 percent.

If a utility could accommodate a first SPS

of 5,000 MW, it could accept another provided it met a less stringent application of

the penetration rule. In other words, the system would benefit somewhat by redundancy

of generating units provided there was a low

probability of both failing at once.

As an example, for a utility to accept a

50,000-MW satellite, it must have a system

capacity of 5,000/0.13 = 38,000 MW. This

exceeds the capacity of any single current

utility. Assuming current average rates of

growth of 3.2 percent for the industry, it

would exceed the capacity of all utilities

save TVA in the year 2000. It might, of

course, be possible for a group of several

utilities with the appropriate total capacity

and adequate grid interconnections to take

on 5,000 MW of power. According to the

rule for reserve capacity, for the group to

then assume another 5,000 MW, its total

capacity would have to be large enough for

the two satellites together to constitute 20

percent or less of a system capacity of

50,000 MW. The exact percentage any given

consortium of utilities would be willing to

——

‘ ~ J Donalek and ) L Wtlysong, “lJtillty Interface Re -

quirements for a Soiar Power System, ” Harza Erlglrleerlrlg CO ,

DOE contract No 31-109-38-4142, report No DO E/E R-0032, September 1978
240 ● Solar Power Satellites

●

●

accept would depend on its view of the

probability of two SPS units and another

unit or transmission line failing at the same

time (see table 52).

As an additional consideration, it should

also be noted that supplying 5 GW of reserve power from elsewhere in the system

would put a great strain on the dispatching

capability of the uti I ity.

Lack of Inertia in SPS Power Generation. —

The frequency stability of a utility system is

directly related to the rotating mass or

mechanical inertia of its collection of

generators. It is, in effect, analogous to a

giant flywheel kept in motion by numerous

small driving elements on its rim. Just as a

flywheel adjusts only slowly to a sudden

removal or addition of individual driving

elements, the utility network takes several

seconds to adjust to the loss or gain of

megawatts of power. A generator added to

the system adds additional mechanical inertia as well as power. Because the SPS

reference design wou [d add power but no

additional inertia, i.e., it might come on or

go off line virtually instantaneously, it

would create surges that would be difficult

for the system to accommodate. In order to

use SPS-generated power, the utilities would

have to develop new modes of ensuring frequency stability and control since the present operating mode depends implicitly on

the mechanical inertia of the system. One

possibility is to add short-term (15 minutes

to 1 hour) battery storage capacity to the

rectenna. Such an adjustment would add a

smal I amount to the cost of SPS power.

Variations in SPS. – Rectenna power output

wou Id vary seasonal Iy because of the eccentricity of the Earth’s orbit. As currently

designed, the SPS would deliver 5,000 MW

when the Earth is at maximum distance from

the Sun. At its closest approach during the

northern winter, each rectenna will deliver

about 10 percent more power, or 5,500 MW.

However, because the variation has a yearIong period, it would be relatively easy to

adjust for it continual Iy.

Short-term variations would be much

more serious. Around the equinoxes, the

satel I ite wou Id I ie in the Earth’s shadow for a

short period each night around midnight.

These “eclipses” of the satellite would vary

trom a few seconds duration at the start of

the 31-day eclipse period to a fu I I 72 minutes

at the equinox and then decrease again to

zero. Because the antenna array wou Id requ i re a warmup period of 15 to 60 minutes,

outages at the rectenna would vary from 30

to 140 minutes. Because the eclipses would

be highly predictable and would occur at

midnight in late March and September when

loads are often low (typically 40 to 60 percent of the peak for summer peaking

systems), they wou Id be unlikely to constitute a problem for the system’s reserve

capacity. * However, following the load

swing during the shortest eclipses would

place a strain on the ability of the utility to

respond because of the need to replace

5,000 MW very rapidly unless storage were

[n place.

Without short-term storage, the rate at

which SPS power would decrease during an

eclipse would undoubtedly pose control

problems for the grid. As the satellite

entered the Earth’s shadow, it would lose

power at the rate of 20 percent per minute,

too fast for the grid to respond. In general,

the maximum power fluctuation a grid can

accommodate is about 5 percent per minute. However, it would be possible to shut

down the satellite at an acceptable rate

somewhat ahead of the eclipse.

The satellites and rectennas would require

replacement or maintenance of numerous

components (klystron amplifiers, solid-state

amplifiers, laser components, photocells,

dipole antennas, etc.) several times a year.

Normally the outages associated with

routine maintenance could be scheduled

during periods of low electricity demand

and are estimated22 to constitute a loss of

* I he cfelmands on different utility systems vary regionally

Thu\, the truth of this statement must be examined on a reglonby-r(~glon basis

“ I Grev “Satellite Power System Technical Options and Economics, ‘ OTA working paper, Solar Power Satelllte Assessment,

197’4
Ch. 9—institutional Issues . 241

120 hr/yr of SPS power. Assuming maintenance could be scheduled during eclipse

periods, the total time the satellite would be

unavailable due to maintenance could be

considerably less than this.

Boeing23 has summarized the various

losses of power to which the referenced SPS

might be subject (table 52). Conspicuously

missing, however, is the possibility of

satellite equipment failure. It will be of considerable interest to everyone concerned to

identify as many potential sources of

unp/anned SPS shutdown as possible.

Other possible variations in the amount of

transmitted power have to do with the mechanism for controlling the position of the

beam on the rectenna, which would be accomplished by a pilot beam directed from

the rectenna to the satellite in space. Because of the finite time of travel in space for

an electromagnetic signal, the time between

sensing a position error at the rectenna and

correction of it at the rectenna would be

about 0.2 see, causing an oscillation in

power output at a frequency of 5 Hz. Again,

the 5,000 MW nominal output would strain

the capabilities of the utility grid to follow

the resultant load variations if short-term

storage capacity were not made a part of the

SPS system.

● Power Reception, Transmission, and Distribution. –At the rectenna, the power collec2“’SPS/Utillty Grid Operations, ” sec 14 of DI 80-25461-3, Boeing Corp

Table 52.—PotentiaI for Power Variations From the Reference System SPS

Average Average

duration of Maximum yearly

Frequency of outage per Total power energy Time to

Range occurrence occurrence outage reduction loss maximum Scheduled

percent per year minlyr hrlyr GW GW hr power loss Yes No .

Source of power

variation

Spacecraft maintenance

Eclipse . . . . . . . . . . . . . . . . . .

o-1oo

0-1oo

2

62

2 X 3,600

3,376 total

71 maximum

per/occurrence

120

56.26

5

5

1.25

0.5

1

0.5

0.425

0.335

0.29

0.15

0.25

0.0005

600

281.3

439

109.5

15

14

10

0.35

0.28

0.24

0.24

0.06

0.0015

6 min

1 min

1 min

5 min

10 sec

30 min

100 ms

100 ms

lm

1s

I s

0.3 s

1s

x

x

x

Eclipse with shutdown

and startup. . . . . . . . . . . . . .

Wind storm. . . . . . . . . . . . . . . . .

Earthquake. . . . . . . . . . . .

Fire in rectenna system ... .

Meteorite hit of

spacecraft equipment .

Rectenna equipment

failure . . . . . . . . . . . . . . .

Precipitation . . . . . . . . . . . . . . .

Pointing error. . . . . . . . . . . . . . .

Ionosphere. . . . . . . . . . . . . . . . .

Ground control

ecluir)ment failure . . . .

5,270

5,260

1,800

840

87.8

87.6

30

14

75-1oo

90-100

80-100

0.01

0.01

0.01

x

x

x

90-100 0.01 1,200 20 x

91.5-100

93.3-1oo

94.8-100

98.5-100

50

1

0.6

10

0.833

0.833

0.833

3.32

x

x

1

50

5,000

20 x

x

x

95-1oo 5 3 0.25

Aircraf~ shadow. . . . . . . . . . . . . 99.99-1oo 20 20 m 0.3

1 m maxi

occurrenc e

Total without shutdown/startup: 331 hour (3. i’i’Yo) 1,030.8(2.350/~)

without shutdown/startup: 362 hour (4.1 20/. ) 1,188.5(2.71 %)

SOURCE: “SPS/Utiiity Grid Operations”, sec 14, D180-25461-3, Boeing Corp.
242 “ Solar Power Satellites

tion system would be divided up into units

of 320 MW or less. The loss of any one or

even a combination of several power blocks

would present few problems for the grid

because they would be relatively small compared to 5,000 MW. Transmission would be

over four to five 500 KV lines or eight 345

KV lines. The loss of one of the transmission

lines should not affect the stability of the

system or the operation of the SPS. In the

event of decreased load requirements, some

excess power could be absorbed by the

rectenna as heat. Sharp drops in power demand (e. g., an open circuit due, say, to a loss

of several transmission lines) might cause

overheating of the rectenna diodes if the

system were unable to dissipate the excess

power quickly enough. Hence, protective

measures would be required.

Maintenance of the dipole antennas and

rectifiers in the rectenna might present a major expense for the utility. Although the

mean time to failure is projected to be 30

years, 24 this would mean that on the average, 7 to 8 diodes (in the rectifier circuit)

could be expected to fail every second, zs

leading to an overall failure rate of 3 percent

per year. Increased quality control of the

manufactured components might mitigate

some of the replacement needs by decreasing the failure rate. This procedure, though

more expensive per unit, might be less expensive than replacing failed components.

Operating Capacity Factor. – In order to

maximize capital investment, the SPS, if developed, should be operated as close to its

“nameplate rating” as possible, i.e., 5,ooO

MW. However, during periods of very light

load (e.g., at night during the spring and fall)

even current baseload nuclear and coal

units must sometimes be run at less than fu II

capacity in order to follow the load swing.

Such factors would make the real operating

“R Andryczyk, P Foldes, j Chestek, and B Kaupang “Solar

Power Satelllte Ground Stations, ” IEEE Spectrum, July 1979,

“Satellite Power Systems Utility Impact Study,” EPRI AP-I 548

TPS 79-752, September 1980 J C Bohn, j W Patmore, H W

Falnlnger

‘5A D Kotin, “Satellite Power System (SPS) State and Local

Regulations as Applied to Satellite Power System Microwave

Recelvlng Antenna Faclllties, ” DO E-H CPIR-4024-05, 1978

●

capacity of the reference SPS less than its

maximum capacity, thereby causing it to be

more expensive.

Rectenna Siting. — The land requirements for

the SPS reference system are “large (see ch.

8). At 350 latitude the rectenna plus its exclusion area would cover an elliptical area

some 174 km2 in extent. By comparison, the

city of Chicago is 57o km2, and Washington,

D. C., 156 km2. Finding available land far

enough from population centers and military installations (to make potential electromagnetic interference slight) and near

enough to the load centers to make transmission costs acceptable would not be a

trivial exercise. Rectenna siting would involve the various regulatory agencies and

wou Id have to be addressed by uti I ities very

early in the overal I planning process.

Utilities in far northern latitudes would

generally find siting more difficult because

the necessary rectenna area and rectenna

exclusion area increases with increasing

latitude. Some of the most acceptable locations are in the Southern and Southwestern

United States where terrestrial photovoltaics and solar thermal devices will also be

most economic to operate. Offshore siting

wou Id also be possible, though this option

wou Id require extensive study.

The Solid-State Variation

The sol id-state sandwich appears to be more

economical to build and place in orbit in

smaller units (about 1.5 GW),26 mitigatingautomatical [y problems arising from the control of 5 GW of power from the reference

system I n addition, a smaller rectenna would

make it possible to place the rectenna closer

to load centers or in offshore locations.

Because it is a microwave system, it would

share the same stability problems that the

reference system wou Id experience.

Laser System

The laser system would present a different

set of challenges and opportunities for the

—

) h H a n I ev, op c It
Ch. 9—institutional Issues ● 243

utilities. Because it can generate electricity by

employing infrared radiation to heat a boiler,

it could perhaps be used to repower existing

coal, oil, or nuclear facilities. A ground-based

thermal collector would generate steam that

could be used directly to drive a turbine. In addition, the scale of the proposed satellite/

ground system (100 to 500 MW) would fit existing utility capacity quite wel 1. For cases where

the laser were used for repowering an existing

facility, no new transmission lines would be

needed.

On the other hand, several intrinsic Imitations of the proposed laser system would make

it difficult for the utilities to integrate it into

their grid:

● Weather Limitations. — Although lasers of

the overall power and power density of

the proposed laser system could burn

through light cloud cover, heavy clouds

would make it unusable. Thus, it would be

unsuitable in areas where clouds cover

the region for more than a few percent of

the year. It might be possible to use it in

regions where there are more receiving

stations than lasers to support them. Then,

if station A were covered by clouds, for

example, the laser feeding that station

could be redirected to station B that was

under no cloud cover. The resulting extra

laser radiation at station B could then be

used to generate more electrical power at

that station to compensate for the loss of

power at station A, assuming that B had

the necessary extra capacity. This arrangement could work wel I for selected parts of

the country, i.e., where the likelihood of

cloud cover forming simultaneously over

several stations was smal 1. However, since

cloudy conditions tend to occur over

large sections of the Nation at one time,

the practicality of this notion would be

limited.

Mirror System

A mirror system would be the most highly

centralized technology of the four alternatives. Its proposers envision a few energy

parks in which the increased daylight would be

used t o generate electrical energy — or

perhaps, hydrogen. How it might be integrated

into existing uti I ities is unclear. As an electrical

system, it would require long transmission

lines leading from the energy parks to the

point of end use. However, hydrogen generated at the site could be transported by

vehicles to other destinations.

This concept appears to require a national

grid in order to make effective use of the large

generating capacity of the site (from 10 to 135

GW). Stability would be much less of a problem for SOLARE S than for the microwave system because of the large number of satellites

that would reflect sunlight, the inclusion of

storage in the system, and because of the independent blocks of ground-based photovoltalcs or solar thermal plants at the site.

The SO LARES proposal would be subject to

similar problems with clouds as the laser concept. However, the additional radiant energy

rnlght be great enough to dissipate clouds that

would form in the region. For this reason, large

mirrors have also been proposed for weather

mod i f I( at ion.27

Regulatory Implications of SPS28

Although this area has received only a cursory investigation at this time, it is clear that

the potential for new forms of financial support and management structures for the SPS

might engender new regulatory modes. I n general, the SPS is I ikely to lead to greater centralization of the Nation’s utility structure,

leading in turn to a strong need for coordination between neighboring Public Utility Commissions or perhaps to completely new structures for regulating utilities.

Local v. Regional Control

Utilities have generally entered into a

greater degree of cooperation with utilities in

other States than have their associated

regulatory agencies. This state of affairs will

‘ Va)k, op clt

‘“M Cer$ovltz, “Report on Certain Economic Aspects of the

SP~ Energy Program, ” OTA Working Paper, SPS Assessment,

1980
244 ● Solar Power Sate//ites

have to change with increasing use of highcapacity generating units and greater grid interconnections. A move toward regional planning and control will likely also come about

because of the current disparity between

States in siting and other regulations, making it

more attractive for utilities to build in States

where regulations are not as stringent or to

purchase power from utilities that have a

surplus of generating capacity.

In order to regulate their processes, new regional regulatory agencies are likely to be set

up long before SPS could be part of the utility

grid, leading to greater grid interties. The introduction of an SPS would undoubtedl y

hasten the process because the larger the grid,

the more easily outages from a single rectenna

or a laser receiver could be handled. The

intermediate-scale sol id-state system would fit

into this kind of structure easily, but a larger

scale SPS such as the reference system or

SOLARES would necessitate an even more

widespread system than is now envisioned.

Although the laser system might be used to

repower inter mediate-s i zed generating

facilities, the ever present possibility of

massive cloud cover would require system interties in order to make the most efficient use

of the available laser satellites.

Site Decisions*

Siting would be a major issue for each one

of the alternative technologies and would also

require the development of regional cooperation. A major question in SPS siting decisions is

who would have the control; local, State,

regional, or national entities? Currently, State

or local regulatory boards make the ultimate

decisions concerning plant siting. The Nuclear

Regulatory Commission and the Environmental Protection Agency review these decisions.

Except for Federal or State land, the planning

for a 174 km’ rectenna would likely involve

several local jurisdictions, one more of whose

land use regulations may not be compatible

with an SPS rectenna. However, if the need for

SPS power were great, there might be adequate reason to supercede local regulations in

*See also chs 8 and 9, pt C

siting a rectenna. A single 5,000-MW rectenna

could serve a large population, one which is

very likely to be distributed across State I ines.

Coordination of regulatory authority could

come from voluntary interstate agreements or

from federally mandated regional planning.

The current debate about energy parks

would be instructive in identifying and resolving some of these issues. Along with this, the

trends toward regional izing economic control

on energy facilities and instituting a national

power grid could provide the institutional

framework for addressing siting issues for a

rectenna or SOLARE S energy park.

Rate Structure

The magnitude of the capital investment

that SPS and other future technologies would

require wou Id certainly cause some alteration

of the utility rate structure. Just what form

these alterations might take is currently

unclear because they depend heavily on the

form that the SPS companies would take and

how they might be f inanced.

For example, if the utilities were to own individual SPS plants, they would wish to include their capital costs during construction

(current work in progress) in the current rate

base. Most States are presently unwilling to

allow this. However, the extraordinarily high

capital costs of other sorts of new generating

capacity may make this scheme a necessity.

(In the other hand, if SPS power were to be

bought directly from an SPS corporation and

sold to the customer, the concern about adding capital costs during construction to th e

rate structure would be eliminated for the utility regulatory agency and shifted to another

sector of the economy (though they would still

be reflected in busbar costs).

SPS Corporations and the Utilities.

Currently, the utilities purchase equipment

and knowhow from competing corporations

who build and service generating equipment.

Because of the scale of investment necessary

to supply the supportive infrastructure for

building an SPS, the SPS corporation might

wel I evolve as a monopoly, requ i ring
Ch. 9—institutional Issues . 245

monopoly-type regulation on the Federal level.

Whether generating plants or power are sold, it

is likely that the Federal Government wou Id be

heavily involved in the regulation of SPS rates

and in siting, reliability, and other aspects of

integrating the SPS into the utilities’ structure.

Such a state of affairs would be likely to lead

to a greater degree of centralization of the

electrical industry whether a national power

grid were instituted or not.

General Implications for the SPS

Centralization v. Decentralization

Two opposing forces currently affect the

utilities industries— a move towards greater

centralization and an opposite trend towards

greater decentralization. On the one hand,

economies of scale, shared facilities, and the

benefits of regional planning make greater

centralization attractive. On the other, the

desire of individuals, communities, and many

companies for a greater degree of energy selfreliance for economic or social reasons suggests that the utilities will have to adjust to an

increased demand for grid-integrated dispersed systems.29 The utilities are just beginning to

address these issues squarely. Market pressures may make dispersed units increasingly

more attractive (see ch. 5, Energy in Context) at

the same time that the Federal Government

supports the development of new central technologies. The main issue for the utilities to address is how to accommodate both ends of the

scale in their planning.

Market Penetration

From the point of view of the utilities that

would either purchase SPS generated power

for distribution in a grid or purchase receiver

installations to incorporate directly into their

own systems, the ultimate total volume of SPS

generated power would depend on a number

of factors in addition to cost. Even if the

busbar cost of SPS electricity was highly competitive with other future options, SPS market

penetration could be limited by reliability

requirements and by the technical difficulties

“D Morris and J Furber, “Decentralized Photovoltalcs” OTA

Working Paper, SPS Assessment, 1980

of grid-dispatch that we have already discussed.

● Reserve Requirements. –The criterion that

any two units (e. g., transmission I ine, generating plant, etc. ) in a utility system must constitute less than 20 percent of the total system capacity leads to a minimum size for

any single utility system for a given SPS

capacity (see Planning Process). Thus, two

5,000-MW plants could be accommodated

by a utility system with total capacity of

33,000 to 50,000 MW or greater. Smaller

utilities’ systems could accommodate appropriately smaller SPS plants. But in

making decisions about whether to proceed

with SPS or not, it is important to estimate

how much total SPS capacity the U.S.

utilities grid overall could accommodate.

The projected total capacity of th e

reference system is 300 GW. Could the utilities grid in 2030 or 2040 accommodate that

capacity?

Simply scaling up from the individual utility or utility grid, using the 20 percent

criterion, 300 GW total SPS capacity implies

1,500 CW total electrical capacity in 2030 or

2040, about 2‘A times current capacity.

It is clear that under these stringent conditions, a low electricity demand would preclude development of SPS from the utilities

point of view. The 20-percent requirement is

certainly overly stringent, since in effect, it

implicitly assumes that the entire SPS fleet

wou Id fail at one time (i. e., no reserve power

would be available from other utilities). On

the other hand, satellites that would be subject to eclipse (i. e., all those in geostationary

orbits) would be eclipsed in groups, not singly. For a few days around the equinoxes, approximately 18 satellites would be eclipsed

at once. * Roughly speaking this means that

a band of Earth some 1,250-miles wide in

longitude would suffer SPS power outage at

one time. Thus, there is a distinct limit to the

amount of lost generating capacity that

nearby utilities could supply during the

eclipse period. Utilities and their regulatory

commissions would only be I ikely to in-

‘A ~atelllte placed at each degree of longitude corresponds to

15 ~atel I ltes per hour of time
246 ● Solar Power Sate//ites

●

crease their proportion of SPS beyond the 20

percent or so of reserve capacity if they

were consistently able to draw power from

beyond the “shadowed” region, or if the

March/September night peaks are low

enough to offset this difficulty. In other

words, the larger the grid served by SPS the

smaller the reserve capacity that would be

required in any one region.

For the country as a whole then, a 20-percent penetration for the reference SPS or

any geostationary SPS must be seen as an

average limit. Utilities with appropriate

backup could accept more. Others, because

of their size, location, or special needs

would only accept less than 20 percent.

A 20-percent penetration of SPS would

constitute 120 GW in the low scenario and

about 490 GW in the high one. At a 90-percent capacity factor, the contribution of

electrical energy from SPS would be 3.2

Quads in the low scenario and 13 Quads in

the high scenario (44 percent of the total

electrical energy consumed in both cases).

Vu/nerabi/ity. –Another aspect of SPS that

the utilities would certainly investigate in

comparison with other generating options is

its vulnerability to hostile actions~” (see ch.

7), and to unforeseen technical failure.

Of perhaps far more concern to the utilities would be any vulnerability to technical

failure (especially common mode failure) or

to human error. As noted earlier, the utility

grid would experience some difficulties in

adjusting to planned outages from the reference SPS. Unplanned ones would be far

more difficult to adjust for, though they are

a common feature of utility operation. The

potential for unplanned failure of any of the

alternative SPS options would only be fully

known if a decision is made to proceed with

one option and a full-scale demonstration

were built and tested extensively.

Perhaps the most technically sensitive

component of the satellite system is the

‘“P Vajk, “The Military Impllcatlons of Satellite Power Systems” NASA/DOE SPS Program Review Meeting, April 1980, Lincoln, Nebr

beam-focusing apparatus. In the microwave

design, a pilot beam sent from the rectenna

to the satellite antenna would control the

phasing of the beam transmitters. With the

loss of the pilot beam, the SPS power beam

would quickly defocus, a safety feature that

would prevent accidental or intentional

wandering of the beam. The laser beam

would be controlled in a similar manner. It

would be important to design this apparatus

to be insensitive to minor perturbations in

operating mode, yet sensitive enough to

maintain its safety qualities. Orientation of

the reflecting mirrors of the SOLARES system would be entirely mechanical and

would be controlled by built-in thrusters. Because the mirror system would be highly redundant, the loss of one mirror would not be

catastrophic. It would also be essential to

design the SPS to be as free as possible from

human error. As the nuclear industry realizes, designing a technologically complex

system in which the potential for human error is small is a difficult and complex task.

Here again, experience with operating

systems wculd be essential to utility acceptance.

System Comparison

The most acceptable SPS option for the current utilities to pursue may be the solid-state or

a similarly sized microwave. It would provide

baseload power with minor weather interference at a scale more in keeping with current

uti I ity practice (i e., 1.5 GW). If future utility

systems develop the capability and the experience to handle larger increments of generating capacity, an SPS similar to the

reference system would be more acceptable,

though siting problems might be very great.

The laser and mirror concepts, though offering some interesting potential, suffer from

severe weather constraints. The possibility that

laser SPS could be used to repower fossil fuel

plant~ wou Id make it of particular interest in

regions of relatively low cloud cover. One of

the significant drawbacks of the mirror concept is that it wou Id require the utility and

overal I energy industry to make a radical
Ch. 9—institutional Issues . 247

change from its current structure because of

its very high degree of centralization (10 to 135

GW per site). This would be particularly true

for an SPS system operating in other countries

where the grid system is either nonexistent or

very smalI (see ch. 7, International Issues).

Timing of Grid Integration.

If SPS followed the pattern of other new

energy technologies it would take a long time

to be integrated into the utilities structure. The

reference system scenario31 suggests that the

first SPS could be deliverig power to the grid

in about 20 years time. But nuclear power,

which has been used for generating steam for

30 years, and became an active option for the

utilities in 1960 still constitutes only 9 percent

of the country’s total capacity (54,000 MW). *

In the face of this past experience, it seems

more Iikely that the demonstration and testing

phases of the SPS would be longer and therefore involve higher costs than can presently be

envisioned. The utilities are faced with providing reliable power to their customers. Looking at SPS from a utilities standpoint, it seems

highly unlikely that the first SPS would be part

of the utility grid before 2010.

This estimate is based on technology similar

to the reference system technology. Developing a laser SPS might take considerably longer

because we simply have less experience with

high-powered lasers. The SOLARES system

would be technically easier to build, but the institutional and political barriers to creating the

““Satellite Power System Concept Development and Evaluation Program Reference System Report, ” op clt

* Nuclear power actual Iy produce~ 13 percent of the electricity

sol d

associated large energy parks could well slow

its development to beyond 2020.

Rate of Implemental ion

The reference system assumes additions of

10,000 MW per year to the grid. Assuming electricity demand makes feasible 10,000 MW additions to U.S. generating capacity, it is unlikeIy that the rate would begin at that high level.

Again, the utilities would want to have considerable experience with the first SPS before

they would be willing to invest in additional

units. Thus, it is more likely that the annual

rate of implementation would begin at less

than 5,000 MW on the average and build to

higher levels as utilities gain experience and

(onfidence in SPS.

Planning for SPS

Acceptance of SPS by the utilities would depend on a number of factors, not the least of

which would be utility involvement in planning

for SPS. But for the utilities to invest their time

and money in such an effort, they would have

to be convinced that it is worth their while.

Thus, SPS must be considered to be economicalIy, environmentally, and socially acceptable compared with the other future energy

options. Much depends on a comparative

analysis of the available options. And because

comparative assessment is necessarily a process carried out over many years, the utilities

must Involve themselves in all phases of that

process. A comparative assessment done today, though instructive, is as a snapshot compared to a motion picture. As we know more

about each technology in the comparative

group, the particular parameters will change,

leading to a reassessment of the desirability of

each technology.

ISSUES ARISING IN THE PUBLIC ARENA

SPS Debate

Public involvement in the development of

technologies has grown significantly in the last

two decades. Debate has focused on the environmental. health and safety. economic and

miIitary issues surrounding new technologies,

The supersonic transport, nuclear powerplants,

PAVE PAWS radar facilities and high-voltage

transmission Iines are examples of technologies that have been subject to recent public

controlversy. Since SPS wouId probably be a
248 ● Solar Power Satellites

federally funded technology (at least in the

research, development, and demonstration —

RD&D phases) with long-term and widespread

ramifications, public input in the development

process is crucial, especially in the early

stages. Moreover, the potential effectiveness

of public resistance to technological systems,

and the public’s interest in direct participation

makes public understanding and approval imperative for the development of SPS.

The assessment of likely public attitudes

towards SPS is difficult, however, because SPS

is a future technology. At present, public

awareness of SPS, while growing, is minimal.

Even if opinions about SPS were well-formed

today, it is likely that these attitudes would

change with time. Public thinking could be influenced by the other energy and space technologies, perceived future energy demand and

general economic and political conditions. 32

The state of SPS technology and estimated SPS

costs couId also be important determinants. In

addition, the degree of public participation in

the SPS decisionmaking process could play a

part in future opinions about the satellite.

Most public discussion on SPS has been confined to a small number of public interest and

professional organizations. OTA has drawn

heavily on the views of these groups because

they represent selected constituencies that

couId play a key role in influencing future

public thinking and motivating public action.

While OTA cannot determine whether or not

the public would ultimately accept SPS, these

interest groups can help identify the issues and

philosophical debates that may arise in the

future.

Interest Groups

A small number of public interest and professional organizations have expressed their

views on SPS. In general, many of the individuals and groups that support the development of SPS also advocate a vigorous space

program. SPS proponents, represented by organizations like the OMNI Foundation, view the

exploitation of space in general, and SPS in

“Solar Power Satellite Public (lplnlonl~>ue~ Workshop, A

Summary, Feb 21-22, 1980, Office of Technology Assessment

particular, as important means in overcoming

terrestrial energy and resource limits.33 To the

L-5 Society, which has been the most vocal SPS

lobbyist, the satellite system is “a stepping

stone to the stars, ”34 an important milestone

towards the society’s goal, the colonization of

space Groups Iike the Aerospace Industries

Association of America35 and the SUN SAT

Energy Council, a nonprofit corporation

established to explore the SPS concept, 36 37

believe that SPS is one of the most promising

options available for meeting future global

energy needs in an environmentally and socialIy acceptable manner. Professional organizations such as the American Institute of

Aeronautics and Astronautics38 and the institute of EIectrical and EIectronics Engineers39

support continued evaluation of the concept.

Opponents of SPS characteristically support

terrestrial solar and “appropriate” technologies and are often concerned about environmental issues. The Solar Lobby40 41 and the

Environmental Policy Center, 42 for example,

fear that an SPS program would drain resources and momentum from small-scale,

—

‘‘Iblcf

“C Hen$on, A Harlan, and T Bennett, “Concern$ of the L-5

Society About SPS, ” The Final Proceedings oi the ~olar Power

%te//lte Pro~ram Review, Apr ,22-25, 1980, DOE, Cent-800491,

jUIV 1980 p 542

‘

5 Aerospace Industries A$soclatlon, Statement submitted for

the record In So/ar Power ‘5ate//lte, hearings before the Subcomm Ittee on 5pace Sc Ience and Appl lcatlon~, U S House of Representatlve~, Mar 28-30, 1979, pp 241-242

‘“P (; Iclwr, “Solar Power Satelllte Development – The Next

Steps, Apr 14, 1978, In So/ar Power Sate//lte, hearings before the

Sub( omrnlttee on Space Science and Appl lcatlon~, U S House

ot Reprewntdtlves, Apr 12-14, 1978, No 68, pp 165-178

1‘I Freeman (ed ) Space .So/ar Power f3u//etln, VOI 1, No 1 and

2, SLJNSA T [ nergy Council, 1980

‘“ So/,?r Power ‘$ate//ltes, AlAA Posltlon Paper, Nov 29, 1978,

prepared by the AlAA Technical Committee on Aerospace Power

Svstem\, ,]nd the AlAA Technical Committee on Space Systems

‘<’H Brown, “Statement on ‘Solar Power Satellite Research,

Development, and Evaluation Program Act of 1979,’” In So/ar

P~jwer ‘i.~re//lres, hearings before the Subcommittee on Space

S( Ience dnd Appllcatlons, U S House of Representatives, Mar

28- W, 1979, No 15, pp 4-8

“’(’l tlzen \ Energy Project, Solar Power Satelllte$ News Upd’]te, Solar Power Satellite Fact Sheet, Coal ltlon Against Satelllte

Power \y\tems Statement (newsletters), 1980

“~ [)(>[ O$S, ‘ Solar Power Satellite, ” Sun T/me\, July 1979, p p

4.5

“G C)e Loss, testimony In $o/ar Power Sate//lte, hearing s

before the Subcommittee on Space Science and Appllcatlons,

U S House of Representatives, Mar 28-30, 1979, No 15, pp

109-114
Ch. 9—Institutional issues ● 249

ground-based, renewable technologies. They

argue that compared to the terrestrial solar options, SPS is inordinately large, expensive, centralized, and complex and that it poses greater

environmental and military risks. The Citizen’s

Energy Project has been the most active lobbyist against funding SPS and has coordinated

the Coalition Against Satellite Power Systems,

a network of solar and environmental organizations. 43 Objections to SPS also have been

raised by individuals in the professional

astronomy and space science communities

that see SPS as a threat to the funding and

practice of their respective disciplines.

44 45

While there is a wide spectrum of support for

SPS in the advocates’ community, ranging

from cautious support of continued research

to great optimism about the concept viability

and deployment, almost all opponents object

to Government funding of SPS research, development, and deployment.

If the SPS debate continues in the future, it

is likely that several other kinds of groups

would take a stand on SPS.46 For example, antinuclear groups could oppose SPS on many of

the same grounds that they object to nuclear

power: centralization, lack of public input,

and fear of radiation, regardless of kind. Antimilitary organizations might also object to SPS

if they foresaw military involvement. It is likely

that community groups would form to oppose

the siting of SPS receivers in their locality if the

environmental and military uncertainties were

not adequately resolved or if public participation in the siting process was not solicited.

Rural communities and farmers in particular

could also strongly oppose SPS on the grounds

that, like highways and high-voltage powerIines, it would intrude on rural life.

Issues

The issues that repeatedly surface in the SPS

debate are shown in table 53. It should be

“Citizen’s Energy Project, op. cit.

““’’Solar Threat to Radioastronomy, ” New Scientist, Nov. 23,

1978, p. 590.

“

sPeter Boyce, Executive Officer of the American Astronomical Society, prwate communication

“’Solar Power Satellite: Pubiic Opinion Issues Workshop, A

Summary, Feb. 21-22,1980, Office of Technology Assessment

noted that in most of the discussion, it is

assumed that SPS would be a U.S. project (at

least in the near term). If the question of SPS

were posed in an international context, it is

possible that the flavor of the following

arguments wouId be altered considerably. Currently, public discussion is focused on the

question of R&D funding. It is anticipated that

as public awareness grows, the environmental,

health, safety, and cost issues will receive

more public attention. Questions of centralization, military implications and the exploitation

of space could also be important.

R&D PROGRAMS

The primary purpose of an SPS R&D program in the near term would be to keep the

SPS option open. However, opponents argue

that it makes little sense to investigate this

complex, high risk technology when other

more viable alternatives exist to meet our

future energy needs. 47 In particular, they fear

that SPS would divert funds and valuable

human resources from the terrestrial solar

technologies, which they perceive as more environmentalIy benign, versatile, less expensive

to develop, and commercially available sooner

than SPS.48 Opponents also argue that a Government R&D program for SPS would fall easy

prey to bureaucratic inertia, and that no matter what the results of R&D, the program

would continue because the investment and

attendant bureaucracy would be too great to

stop. 49 Moreover, opponents believe that

political inertia will be generated from the

relatively large amount of money that is

presently allocated to organizations with a

vested interest in SPS as compared to those

groups opposed to SPS. In addition, they are

concerned that studies evaluating SPS for the

purpose of making decisions about R&D funding do not compare SPS with decentralized

solar technologies; they argue that without this

kind of analysis, the public would be unwilling

to make a commitment to SPS funding.

“K Bossong and S. Denman, “A Critique of Solar Power Satellite Technology, “ INSIGHT, March 1980

48Cltlzen’s Energy Pro}ect, op. cit

“Solar Power Satellite: Public Opinion Issues Workshop, A

‘$urrtrriary, Feb 21-22, 1980, Office of Technology Assessment

83-316 0 - 81 - 1 7
250 ● Solar Power Satellites

Table 53.—Major Issues Arising in SPS Debate*

Pro Con

R&D funding

● SPS is a promising energy option ●

● The Nation should keep as many energy options open ●

as possible

Ž An SPS R&D program is the only means of evaluating ●

the merit of SPS relative to other energy technologies

● SPS R&D will yield spinoffs to ether programs ●

SPS is a very high-risk, unattractive technology

Other more viable and preferable energy options exist

to meet our future energy demand

SPS would drain resources from other programs,

especially terrestrial solar technologies and the space

sciences

No matter what the result of R&D, bureaucratic inertia

will carry Government programs too far

cost

● SPS is likely to be cost competitive in the energy

market

● Cost to taxpayer is for R&D only and accounts for small

portion of total cost; private sector and/or other nations

will invest in production and maintenance

● SPS will produce economic spinoffs

Environment, heath, and safety

● SPS is potentially less harsh on the environment than

other energy technologies, especially coal

Space

● Space is the optimum place to harvest sunlight and

other resources

● SPS could be an important component or focus for a

space program

● SPS could lay the ground work for space industrialization and/or colonization

● SPS would produce spinoffs from R&D and hardware to

other space and terrestrial programs

● SPS is unlikely to be cost competitive without Government subsidy

● Like the nuclear industry, SPS would probably require

ongoing Government commitment

● Projected cost are probably underestimated considerably

Ž The amount of energy supplied by SPS does not justify

the cost.

Ž SPS risks to humans and the environment are potentially greater than those associated with terrestrial

solar technologies

. Major concerns include: health hazards of power transmission and high-voltage transmission lines, land-use,

electromagnetic interference, upper atmosphere effects, and ‘(sky lab syndrome” —

● SPS is an aerospace boondoggie; There are better

routes to space industrialization and exploration than

SPS

● SPS is an energy system and should not be justified on

the basis of its applicability to space projects

International considerations

●

●

●

●

One of the most attractive characteristics of SPS is its ●

potential for international cooperation and ownership

SPS can contribute significantly to the global energy ●

supply

SPS is one of few options for Europe and Japan and is

well suited to meet the energy and resource needs of

developing nations

An international SPS would reduce concerns about

adverse military implications

SPS could represent a form of U.S. and industrial nations’ “energy imperialism,“ it is not suitable for LDCs

Ownership of SPS by multinational corporations would

centralize power

Military Implications

● The vulnerability of SPS is comparable to other energy . Spinoffs to the military from R&D and hardware would

systems be significant and undesirable

● SPS has poor weapons potential . Vulnerability and weapons potential are of concern

● As a civilian program, SPS would create few military

spinoffs
Ch. 9—institutional Issues ● 251

Table 53.—Major Issues Arising in SPS Debate* —Continued

Pro Con

Centralization and scale

● Future energy needs include large as well as small- • SPS would augment and necessitate a centralized inscale supply technologies; urban centers and industry frastructure and reduce local control, ownership, and

especially cannot be powered by small-scale systems participation in decisionmaking

alone

● SPS would fit easily into an already centralized grid ● The incremental risk of investing in SPS development is

unacceptably high

Future energy demand

. Future electricity demand will be much higher than . Future electricity demand could be comparable or only

today slightly higher than today with conservation

. High energy consumption is required for economic ● The standard of living can be maintained with a lower

growth rate of energy consumption

● SPS as one of a number of future electricity sources ● There is little need for SPS; future demand can be met

can contribute significant y to energy needs easily by existing technologies and conservation

● Even if domestic demand for SPS is low, there is a • By investing in SPS development, we are guaranteeing

global need for SPS high energy consumption, because the costs of

development would be so great

———.

aArguments mainly focus on the SPS reference system.

SOURCE: Office of Technology Assessment.

Advocates, on the other hand, view SPS as a

potentially viable and preferable technology. so

They argue that an R&D program is the only

means of evaluating SPS vis-a-vis other energy

technologies. Moreover, if the Nation can afford to spend up to $1 billion per year on a

high-risk technology like fusion, it could certainly afford SPS research that would be much

less expensive.

51 proponents maintain that SPS

research will yield many spinoffs to other

technologies and research programs whether

or not SPS is ever deployed. 52 53 They also respond to claims of bureaucratic inertia by

citing several cases in which large projects,

such as the SST and the Safeguard ABM system, were halted in spite of the large investment. 54 They argue that at the funding levels

currently discussed for R&D, the risk of program runaway is very low.

COST

Economic issues have played center stage in

the SPS debate. Almost every journal account

of SPS (particularly those critical of the

satellite) has highlighted its cost. 55 56 57 T h e

‘“P. Glaser, “Solar Power From Satellites, ” Physics Today, February 1977,

“Solar Power Satellite: Public Opinion Issues Workshop, A

Summary, Feb. 21-22, 1980, Office of Technology Assessment

52P Glaser, “Development of the Satellite Solar Power Station, ” in So/ar Power from Sate//ites, hearings before the Subcommittee on Aerospace Technology and National Needs, U S

Senate, Jan 19,21,1976, pp 8-35

‘IT A Heppenheimer, Co/onies in Space (City, State: stackpole Books, 1977)

“Solar Power Satellite: Public Opinion Issues Workshop, A

summary, Feb. 21-22, 1980, Office of Technology Assessment.

“J Marinelli, “The Edsel of The Solar Age,” Environrnenta/Action, July/August 1979,

“R Brownstein, “A $1,000,000,000 Energy Boondoggle; Science Fiction Buffs Will Love It, ” Critica/ Mass )ourna/, June 1980.

“L Torrey, “A Trap to Harness the Sun,” New scientist, J UIY

10, 1980
252 ● Solar Power Satellites

predominant questions revolve around R&D

priorities and capital and opportunity costs. In

addition, the calculation of costs themselves

and cost comparisons between technologies

could be subject to extensive scrutiny and

debate.

Proponents argue that the only cost open for

public discussion is the cost of RD&D to the

taxpayer. 5859 The bulk of the SPS investment

would be carried on by the private sector in

competition with other inexhaustible energy

alternatives. Furthermore, much of the RD&D

cost could be returned from other space programs such as nonterrestrial mining and industrialization that build upon the SPS technological base. ’” Advocates also contend that an

SPS program would produce economic spinoffs by providing domestic employment and

by stimulating technological . innovation for

terrestrial industry.61 Some proponents also

argue that as an international system, SPS

could lead to the expansion of world energy

and space markets. 62 63 In addition, in a global

scenario, the United States would bear a smaller portion of the development costs. Finally,

advocates believe that in spite of the large investment costs, SPS would be economically

competitive with other energy technologies. 64 65

Opponents argue that the present cost estimates are unrealistically Iow. 66 They expect

that like other aerospace projects and the

Alaskan pipeline, the cost of SPS would signifi5’Solar Power Sate//ite: Pub/ic Opinion /ssues Workshop, A

Summary, Feb. 21-22, 1980, Office of Technology Assessment.

“K Heiss, testimony in So/ar Power Sate//ite, hearings before

the Subcommittee on Space Science and Applications, U S

House of Representatives, Mar 28-30, 1979, pp 132-158

‘“G. Driggers, letter and statement submitted for the record In

So/ar Power Sate//ite, hearings before the Subcommittee on

Space Science and Applications, U S House of Representatives,

pp 407-416

“Glaser, “Solar Power Satellite Development–The Next

Steps,” op clt

‘

2 So/ar Power Sate//ite: Pub/ic Opinion Issues Workshop, A

Summary, Feb. 21-22, 1980, Office of Technology Assessment

“Heppenheimer, op. cit

“P. Glaser, “The Earth Benefits of Solar Power Satellites, ”

Space Solar Power Review, VOI 1, No 1 &2, 1980

‘

5R. W Taylor, testimony in So/ar Power From Sate//ites, pp

48-51.

“K, Bossong, S, Denman, So/ar Power Sate//ites or How to

Make So/ar Energy Centralized, Expensive and Environmenta//y

Unsound, report No. 40, Citizens Energy Project, June 1979

cantly increase as SPS is developed. Furthermore, the U.S. taxpayers would be required to

support this increase and to maintain an ongoing commitment to SPS above and beyond the

RD&D costs, just as they have for the nuclear

industry. ” The National Taxpayers Union, in

particular, sees SPS as a “giant boondoggle

that will allow the aerospace industry to feed

its voracious appetite from the federal

trough.” 68 Opponents argue that SPS would

not alleviate unemployment substantially

because it provides unsustainable jobs to the

aerospace sector alone.69 Most opponents also

do not believe that SPS will be cost competitive and argue that the amount of energy

produced by SPS would not justify its large investment cost. 70

The most critical issue for opponents is the

question of opportunity cost, i.e., the cost of

not allocating resources for other uses.71 They

argue that a commitment to SPS R&D would

jeopardize rather than stimulate the development of other energy technologies. Opponents

also argue that SPS might foreclose opportunities for alternate land use, Federal nonenergy R&D funding, allocation of radio frequencies and orbital slots, resource uses and

jobs.

ENVIRONMENT, HEALTH, AND SAFETY

Opponents contend that the environmental

risks and uncertainties of SPS far exceed those

of the terrestrial solar options.72 They are most

concerned about the effects of microwaves on

human health, airborne biota and communications systems. Critics of SPS also argue that it

would severely strain U.S. supplies of certain

materials, thereby increasing our reliance on

foreign sources. 73 In addition, opponents ques-

—

“Solar Power Sate//ite: Pub/fc Opinion Issues Workshop, A

Summary, Feb 21-22, 1980, Office of Technology Assessment

“J Creenbaum, National Taxpayers Union, letter to the

Senate Energy and Natural Resources Committee, expressing

views on H R 12505, July 7, 1978

“Richard Grossman, Envlronmentallsts for Full Employment,

private communication, July 25, 1979

7“Bos\ong and Denman, op clt

7’ 50/ar Power Sate//ite Pub//c Opinion Issues Workshop, A

Summary, Feb 21-22, 1980, Office of Technology Assessment

7

’Citizen’s Energy Project, op clt

“] Hooper, Star Gazer’s A/ert, update to “Pie In the Sky”

(newsletter), The Wilderness Society
Ch.. 9—institutional Issues ● 253

tion putting Earth resources in space where

they cannot be recycled or retrieved. ” Opponents also cite the large amount of land

needed for receiver siting, high-voltage transmission lines, the effects of launches on air

and noise quality, the potential for unplanned

reentry of LEO satellites (“Skylab Syndrome”),

reflected sunlight from the satellites and

potential adverse effects on climate and ozone

as serious problems. 75

Advocates, on the other hand, maintain that

compared to other baseload or large-scale

energy technologies, SPS would incur less environmental risk. 76 77 78 In particular, its

climatic effects would be far less severe than

those of fossil fuels and its bioeffects would

probably be much less hazardous than those

of coal and nuclear. Proponents claim that the

principal advantage of SPS as opposed to terrestrial solar and hydroelectric is that it would

ueless land per unit energy.79 Most advocates

are confident that while electromagnetic interference and some atmospheric effects could

be a problem, acceptable methods can be

found to mitigate most of the environmental

impacts of SPS. Some proponents also argue

that one of the major benefits of SPS is that it

transports to space many of the environmental

impacts typicalIy associated with the generation of power on Earth. 80 Moreover, air and

water pollution and resource strains could be

alleviated if the Nation mined the Moon or

asteroids. Some advocates have also stressed

the importance of weighing environmental

concerns against the needs for inexpensive

energy. 81 A few contend that while environmental issues have ranked high in the public

mind, convenience and the cost of energy are

“DeLoss, “Solar Power Satellite, ” op clt

75 Solar Power Satellite: Public Opinion Issues Workshop, A

Summary, Feb 21-22, 1980, Office of Technology Assessment

“C laser, “Solar Power Satellite Development–The Next

Steps,” op clt

zTHeppenhelmer, oP. c ‘

t

“G. O’Nelll, The High Frontier: Human Co/onies in Space (New

York William Morrow & Co , Inc , 1977)

7’Glaser, “The Earth Benefits of Solar Power Satellites, ” op

cit.

‘“C W Driggers, “SPS Significant Promise Seen, ” The Energy

Consumer, September 1980, pp 39-40

“Solar Power Satellite: Public Opinion Issues Workshop, A

Summary, Feb. 21-22, 1980, Off Ice of Technology Assessment

becoming more important. Opponents, on the

other hand, contend that environmental concerns will remain predominant and that the

public perception of environmental risks will

uItimately dictate costs.

Historically, public involvement in technological controversies has often been spurred

by concerns about the environmental risks. Environmental issues couId be very important in

future public thinking about SPS as well. 82 It is

also Iikely that SPS would serve to bring controversies over the impacts of other technologies to the forefront, most notably the bioeffects of microwaves and high voltage transmission Iines (60 cycle). While the public might

be concerned about all environmental impacts

(see table 28), those that most immediately affect people’s health and well-being would

dominate discussion. Moreover, environmental issues would be most focused and

amplified at the siting stages of SPS development (see Siting section). Public acceptance

of SPS wilI depend strongly on the state of

knowledge and general understanding of environmental hazards. It will also depend on the

institutional management of the knowledge;

who determines the extent and acceptability

of the public risk may be just as important as

the data itself.

The most critical environmental issue for the

reference system at present is the biological effect of microwaves, not only because the uncertainties are so great, but also because of the

existing controversy over microwave bioeffects in general. As the proliferation of microwave and radio frequency devices has increased dramatically, this issue has received

considerable attention in the public arena. A

great many newspaper and journal articles, 83

as well as television segments on 60 minutes

and 20/20,84 and Paul Brodeur’s book, The Zapping of America: Microwaves, Their Deadly

Risk and the Cover-Up85 signal growing public

“lbld

“S Schlefelbeln, “The Invlslble Threat, ” Saturday Review,

Sept 15, 1979, pp 16-20

84A Bachrach, Satellite Power System [SPS] Public Acceptance,

October 1978

“Paul Brodeur, The Zapping of America (New York W W Norton & Co Inc , 1977)

83-316 0 - 81 - 18
254 ● Solar Power Satellites

concern over the increase of “electronic

smog. ”

The press has been particularly suspicious of

the motives and conclusions of the apparently

small, closed community of microwave researchers and decisionmakers in the 1950’s and

1960’s. Suggestions of vested interests, conspiracy, and coverups stem from the confidential classification of microwave research by

radio frequency users such as the military and

the microwave device industry and the lack of

attempts to solicit public input. 86 Whether or

not such motives in fact existed, the public and

press, fearful of the word “radiation,” have expressed little confidence in “official” claims

that microwaves are as safe as they are purported to be.

The political edge of the scientific controversy has also been sharpened by several incidents over a 10-year period of microwave irradiation of the U.S. embassy in Moscow. The

peak power of the modulated field was 18

microwatt, far below the U.S. guideline.

8 7

Although neither electronic jamming or surveillance seemed to be the purpose of the

waves, there was concern about attempted

behavior control and health hazards that led

to Project Pandora and other studies. These investigations tended to conclude that the embassy workers did not encounter health hazards traceable to their exposures.88 Few followup studies have been conducted however, and

suspicions still exist. Public opinion seems to

have been influenced by the extensive publicity these episodes have received. Articles questioning the ethics and motives of the State

Department leave the reader feeling that the

issues were never adequately resolved.

Most recently the proposed American National Standards Institute and National institute of Occupational Safety and Health

(NIOSH) microwave standards have been criticized. The Natural Resources Defense Council

‘

b

Ibid.

87 Schiefelbein, op. cit.

88A. Lilienfeld, et al , Foreign Service Hea/th Status of Foreign

Service and Other Employees From Selected Eastern European

Posts Fina/ Report, Department of Epldemlology, the John

Hopkins University, July 31,1978

(NRDC) claims that the NIOSH criteria document that will form the basis of the NIOSH

standard, fails to provide a scientifically and

medically sound standard; while it admits the

existence of many low-level effects, it proposes a thermal standard and fails to adequately address low-level non-thermal effects. 89 NRDC argues that the proposed standard was arbitrarily chosen, just like its

predecessor. NRDC recommends that the

criteria document be recommissioned, that a

balanced team of experts work with NIOSH

and another review the document and that a

temporary emergency standard of 1 mW/cm2

for 10 MHz to 300 GHz, be promulgated.

In spite of the proliferation of microwave

ovens, public resistance to the siting of

technologies that use the radio frequency portion of the electromagnetic spectrum has been

strong and often effective. Local residents

have opposed the construction of broadcasting towers and radar installations, as well

as high voltage transmission Iines (ELF radiation). (See Siting section.)

SPACE

SPS would represent a giant leap in our present commitment to space. To some, this space

component and its supporting infrastructure

wouId be an unnecessary and expensive commitment,

90 while others enthusiastically embrace SPS as the first step towards an extraterrestrial future for human kind. 91 Others argue

that a commitment to space is desirable, but

that SPS would be the wrong route to get there.

It is likely that the discussion of the SPS concept would precipitate extensive debate over

national priorities, domestic space policy and

the international and military implications of

space.

Proponents of SPS argue that space is the

optimum place to harvest sunlight 92 and other

resources that are needed for an Earth plagued

by overpopulation, resource limitations, and a

threatened environment. Many envision a

“’Lou I~ Slesln, letter to Dr Anthony Robbins, NIOSH, fro m

NRDC, j Uiy 11, 1979

9(’ Cltlzen’s Energy Project, op clt

9’Henson, Harlan, Bennett, op clt

92 Brownsteln, op clt
Ch. 9—Institutional issues . 255

future in which the U.S. mines, industrializes

and colonizes space as a hedge against these

limits to growth.93 94 95 SPS is one step in this vision, for it not only would deliver energy to

Earth but would also spur the development of

hardware, management, expertise and energy

for use by other space activities. In fact, some

proponents have suggested that without SPS,

the space program will atrophy; 96 that SPS

would give NASA a clear context in which to

plan other space projects. Some advocates see

SPS, like Apollo, as a way to restore the frontier spirit by dispelling the gloom associated

with limits to growth. 97 98

Many opponents, on the other hand, call SPS

an aerospace boondoggle. ” They argue that

SPS, as an energy system, should not be justified on the basis of its applicability to other

space pro jets. Moreover, it is argued that it is

not necessary to go to space in order to generate technological spinoffs; the Nation can encourage technological competence and innovation in more direct and less expensive

ways. 100 Some critics of SPS also argue that

SPS would serve to escalate and accelerate

confrontations in space.

In the future, public opinion about space

and SPS in particular will be influenced by the

relative status of space programs in this and

other countries.101 For example, the pursuit of

SPS programs in other nations might act as an

impetus for the United States to participate in

or develop its own SPS. In light of the experience with Skylab, it is clear that the success or failure of U.S. space projects such as

the space shuttle will have a marked effect on

public thinking. Grassroots organizations supportive of space, and the popularity of science

fiction and space-oriented entertainment,

could also play a role in determining attitudes

toward the exploitation and exploration of

“Glaser, “Development of the Satellite Solar Power Station, ”

op cit

94tieppenhreimer, oP c ‘

t

950’ Neill, op. cit

9

’Peter Glaser, private communication

97Glaser, “Solar Power Satellite Development–The Next

Steps, ” op. cit

98 Heppenheimer, oP C’t

99 Greenbaum, op cit

‘OOOfflce of Technology Assessment, op cit

101 Ibid

space. A growing public interest in space

utilization or exploration and increased appreciation of the pragmatic benefits of space

could put SPS in a favorable light.102 Equitable

international agreements about the use of

space could also spur support for SPS. On the

other hand, ambiguous space agreements, international conflicts, or the escalation of

space weaponry couId turn public opinion

away from SPS. Negative public thinking

about space activities and SPS could also stem

from the technical failure of a major space

vehicle or satelIite.

INTERNATIONAL CONSIDERATIONS

Beyond its immediate implications as a

space system, there are other international

issues associated with SPS. The satelIite system

is seen as a possible focus for either global

cooperation or global conflict by advocates

and opponents alike. ’03 However, opponents

are especially skeptical of the feasibility of a

muItinational system; they doubt that international cooperation would occur until most of

the existing conflicts on Earth are resolved.

SPS opponents are most concerned that SPS

would represent U.S. “energy imperialism” by

dominating the cultural and technical development of lesser developed countries (LDCs). 104

Reliance on the industrial nations would impinge on third world attempts at energy independence. Furthermore they argue that SPS

wouId do Iittle to alleviate the near term

energy needs of LDCs, whereas most terrestrial

solar technologies could. Opponents also fear

that control of SPS by multinational corporations would accelerate the movement of economic and political power away from individuals and communities.105

The characteristic of SPS that is most attractive to some proponents, on the other

hand, is the potential for multinational

cooperation. 106 107 In fact, a few contend that

‘“l bid

‘)’1 bid

‘

)41 bid

‘

(

’

5 Bossong and Denman, “A Critique of Solar Power Satellite

Technology, ” op cit

‘l’G laser, “The Earth Benefits of Solar Power Satellites, ” op

Clt

‘“7P C laser, “The Solar Power Satellite Research, Development and Evaluation Program Act of 1979, ” testimony In So/ar

Power Satellite, 1979, pp 215-224
256 Ž Solar Power Satellites

this is the only feasible arrangement for SPS;108

a multinational SPS would alleviate many of

the problems associated with a unilateral SPS,

e.g., military implications and high costs. Proponents also argue that SPS would enhance

the economies and industrial development of

LDCs by meeting their primary energy needs.109

They maintain that electricity from SPS could

be used to produce methanol, transported to

rural areas in labor intensive pipelines for

heating, cooking, and small industries. 110 S P S

might also be used for mariculture to provide

food. SPS advocates maintain that for oil- and

sun-poor Japan and Europe, SPS is one of the

very few energy options available. Some

also argue that the deployment of SPS would

slow the proliferation of nuclear technology in

the third world. 2

MILITARY IMPLICATIONS

Military issues are intimately related to

space and international considerations. Proponents stress that SPS microwave and mirror

systems would be ineffective weapons and no

more vulnerable than a terrestrial powerplant. ’ While some believe that a military

presence in space is unavoidable, it is clear

that there are better ways to achieve military

competence than with SPS. A primary concern

for opponents is that SPS would provide a

technological base that would further military

capabilities and serve to escalate military conflicts.

114 Many opponents feel that, like the

shuttle, military involvement with SPS is inevitable and that because of its vulnerability, SPS

would accelerate the need for a military

presence in space. Opponents are also concerned that because of their highly centralized

nature, SPS satellites and receiving stations

would be targets for attack from terrorists and

hostile nations.

[t is likely that the military issue will be of

great concern to the public, although it is not

‘

08 Glaser, private communication, op clt

‘

09 Heppenheimer, op cit

““D Criswell, P. Glaser, R Mayur, B O’Leary, G O’Neill, and

J Vajk, “The Role of Space Technology in the Developing Countries,” Space So/ar Power Review, VOI 1, No 1 & 2, 1980

1l’Bachrach, op clt

1’2Driggers, op cit

“’Office of Technology Assessment, op clt

1141bld

apparent how the military implications of SPS

would be viewed. For example, a perceived

military potential of SPS and its supporting infrastructure might be seen as a real benefit to a

public concerned about both national security

and energy needs. 5 Many might even expect a

military presence in space. The laser system

would probably engender more concern over

military applications than the microwave or

mirror designs. Clearly, future opinion will be

influenced by the state of space weaponry in

this and other nations, future agreements

about the use of space, and the state of terrestrial weapons as well as arms limitations

and the perceived military stature of the

United States relative to the rest of the world.

CENTRALIZATION AND SCALE

Debate over future energy strategies often

involves questions of general social values

rather than a narrow choice of specific technologies. One of the issues fundamental to this

debate is that of centralization of energy production. The degree of centralization underlies

many of the other issues discussed here including siting, ownership, public participation,

military implications, and the choice between

terrestrial solar and SPS.

Opponents of large-scale technologies object to society’s increasing reliance on complex technologies and centralized infrastructures that, they argue, tend to erode the viability of democratic government by concentrating

economic and political power in the hands of a

few, and reducing individual and community

control over local decisions. 116 Critics of SPS

argue that it would augment and necessitate

centralization by requiring a massive financialmanagement pyramid.

117 Utility, energy, and

space companies and Federal agencies would

combine into a simple conglomerate, in which

small business would play little or no part.

They reason that decisions about local energy

development, receiver and transmission line

siting and economic and environmental planning would necessarily be made by Federal

1‘ ‘Ibid

‘“Bossong and Denman, “A Critique of Solar Power Satellite

Technology, ” op cit

‘‘ ‘Citizen’s Energy Project, op clt
Ch. 9—Institutional Issues Ž 257

and industrial decision makers at a national or

perhaps multinational Ievel.

118 Many opponents argue that decentralized solar technologies are preferable to SPS because they

employ a wider range of skilIs, encourage participation of small firms, are more directly accessible to the individual consumer and

equitably allocate their negative environmental impacts to the same people who receive the

benefits. In addition, unlike SPS that must be

built in large units to be economic, terrestrial

solar technologies can flexibly accommodate

large or small variations in energy demand. ’

Moreover, unlike SPS, they do not require

large contiguous land areas, a large initial investment, large energy backup units or a national utility grid to ensure adequate reliability. Dispersed energy technologies are also considered more appropriate for lesser developed

nations because they are better matched to

end-use needs, produce relatively small impacts on local culture and environment and

don’t require foreign financing, materials,

complex infrastructures or hardware. 120 O p -

ponents of SPS also view its scale as a severe

detriment from an energy planning perspective

because the incremental risk of investing in an

SPS development program would be unacceptably high; a case of “too many eggs in one

basket .

121

Most proponents of SPS argue that the Nation’s energy future will be characterized by a

mix of centralized and dispersed energy generating systems, but that only centralized technologies like SPS will be able to meet the

needs of industry, large cities, transportation

and fuel production. 122 In addition, the centralized nature of SPS facilitates its adoption

into the existing electricity infrastructure. 123

Some organizational centralization may result,

but this will occur in the utility and aerospace

sectors, already strongly centralized, and so it

will not cause a significant new concentration

of power.

‘ “Office of Technology Assessment, op clt

‘“DeLoss, testimony in So/ar Power Sate//lte, op clt

““Off ice of Technology Assessment, op cit

“’DeLoss, “Solar Power Satellite, ” op clt

“’Office of Technology Assessment, op clt

‘“R Stobaugh and D Yergin, Energy Future (New York Ran

dom House, 1979)

In generaI, advocates of large-scale technologies Iike SPS maintain that centralized systems are more reliable and easier to implement

than dispersed technologies. Centralized

powerplants also produce environmental impacts that are localized and hence directly affect fewer people. It is argued that dispersed

power generation does not reduce centralized

decisionmaking; in order to be economic these

systems will require mass production, standardization, and regulation and an extensive

distribution and service network. 124 Centralized technologies, at least, are more convenient from the user’s perspective. Advocates

also contend that centralized technologies and

infrastructures are a better means of ensuring

equity among the Nation’s citizens. 125 For example, many people, predominantly in the inner cities, wilI continue to rely on centralized

delivery systems because they cannot afford

the capital costs to do otherwise.

While the public might not couch the problem in terms of “centralization, ” it is clear that

people will be concerned about technologies

and systems that appear to prevent them from

directly influencing the conditions of their

own Iives. 126 Public thinking about SPS will

then be determined by the extent of public participation in the planning and decisionmaking

process, experience with centralized and

dispersed technologies, attitudes towards

energy, space, and utility conglomerates as

well as the perceived influence and benefits

(e g., convenience) of centralized technologies.

FUTURE ELECTRICITY DEMAND

Those in favor of SPS tend to foresee an

energy future characterized by high electricity

consumption and an expanded power grid. 127

Many equate economic well-being to high

energy growth rates.

128 Even if the United

States is not able to absorb all of an SPS

“H Brooks, “Critique of the Concept of Appropriate

Technology”, In Appropriate Technology and Social Values — A

Cr~tlca/ Appraisa/, F Long and A Oleson (eds ) (Cambridge,

M,iss Balllnger Publlshlng Co , 1980)

“Offlc P of Technology Assessment, op clt

2’)1 bid

170fflc e of Technology Assessment, The Energy Context of

SP} Work ~hop, A Summary, September 1980

“Off Ice of Technology Assessment, Solar Power Sate//ite

Public Op/rrlon Issues Workshop, A Summary, Feb 21-22, 1980
258 ● Solar Power Satellites

system, they argue that on a global scale there

will always be high demand. 129 130 Proponent s

also argue that if SPS is able to provide

relatively cheap, environmentally benign and

plentiful energy, then it will be consumed and

demand will be high. ’3’ Some argue that no

matter which demand scenario is finally realized, we need to investigate every possible

electricity option today, so that we have adequate choices in the future.

Most opponents, on the other hand, envision

an energy future dominated by conservation

and solar technologies. 123 Some believe that

electricity should play a minor role in our

energy supply mix because of its thermodynamic inefficiency. 133 Furthermore, most opponents contend that even if electricity demand were to increase somewhat, it could be

satisfied with existing technologies. 134 The y

argue that by developing large-scale energy

systems such as SPS, we are guaranteeing high

energy use because the investment in their

development is so great.

Public attitudes about SPS will depend on

the relative cost and availability of energy, the

advancement and proliferation of electrical

end-use technologies, attitudes towards energy

companies and forecasters of electricity demand, and the sense of energy security as

determined by domestic supply v. reliance on

foreign sources. 35

SPS Technical Options

How might future public reaction to alternative SPS systems differ?136 Table 54 identifies some of the relative benefits and drawbacks of the proposed SPS systems as they

might be perceived by the public.

‘2’O’Neill, op cit.

‘30Glaser, private communication, op clt

‘

J IOffice of Technology Assessment, The Energy Context of

SPS Workshop, Op. clt

I J21bld

‘“A B Lovins, “Energy Strategy The Road Not Taken?” -

Foreign Affairs, October 1976

‘ “Office of Technology Assessment, The Energy Context of

SPS Workshop, op. clt

‘‘sOffIce of Technology Assessment, So/ar Power Sate//ite:

Pub/ic Opinion /ssues Workshop, op clt

‘Jblbid

Siting

Historically, public debate over the introduction of a technology has been most pronounced at the siting stage. It is during the

siting phase that public opposition to a technology has been most vocal, organized, and effective. Citizens have taken direct action

against the siting of powerplants, airports,

prisons, high-voltage transmission lines and

military facilities by forming local and national groups, publicizing their cause through

the media, taking legal action, demonstrating,

and occasionally resorting to civil disobedience and violence. 137 In general, siting controversies revolve around issues of environmental effects, health and safety risks, reduced land values and fair compensation, private property rights, opportunity costs, vulnerabiIity to attack, and public participation in

land-use decisions. 138 It is clear that in the

absence of national land-use policies, conflicts

over land-use priorities will escalate as the

population grows, and friction between rural

and urban America and local communities and

regional or national decision makers will increase ‘‘9

For SPS, siting is a major issue. * SPS would

be particularly prone to siting difficulties

because of its large contiguous land requirements, its potential military implications,

and its use of nonionizing electromagnetic

radiation (e. g., microwaves or lasers) in power

transmission and distribution. This last factor

is most important because of considerable

uncertainties associated with the environmental and health risks of electromagnetic radiation as well as possible interference with electromagnetic systems. These uncertainties and

-—- —

‘“L ( aldwell, L Hayes, and I MacWhlrtey, Citizem and the

/ nvtronment Case Stucfles in Popu/ar Act/on (Broom lngton, Ind

I ndlana University Press, 1975)

‘ “OftIce of Technology Assessment, op clt

‘ “lbl(l

*It ts assumed that SPS receivers would be sited on land Offshore locations are also possible and might alleviate many of the

~PS Ian(j-use problems, but are not specifically addressed here

Also not considered here are possible multiple land uses If it can

he shown that land can safely and economically be used for

iltlng 5 PS receivers and other uses (e g , agriculture, pasture

land) simultaneously, then siting on private land might not be a

problem However, In the absence of detailed assessments on the

( osts and environmental Impacts of multiple uses, it IS assumed

I n th IS section that I and IS dedicated to SPS receivers alone
Ch. 9—institutional Issues ● 259

Table 54.—Potential Benefits and Drawbacks of SPS Technical Options

Advantages Disadvantages

Laser system

. Does not use microwaves ● Possible weapon

. Of SPS systems, requires less land area per site and ● Health and safety impact of beam wanders

can deliver smaller units of energy ● Weather modification

Mirror system

● Most environmentally benign of SPS systems ● Largest land requirements per site

● Least weapons potential of all SPS systems ● Illumination of night sky

● Least complex to demonstrate, most immediately ● Weather modification

reliable system . May fall out of low-Earth orbit

● Possibly least expensive system

Solid state

. Can deliver smaller units of power than mirror or • Microwave bioeffects

reference system ● Electromagnetic interference

● Land per site is smaller than mirror or reference

system

. Satellites in GEO (in vulnerable to unplanned reentry)

and can be placed over the ocean

● Less weapons potential than lasers

. Fairly well-developed technology

Reference system

● Satellites in GEO (invulnerable to unplanned reentry) . Microwave bioeffects

and can be placed over the ocean • Electromagnetic interference

● Less weapons potential than lasers

● Fairly well-developed technology

SOURCE: Office of Technology Assessment

their institutional management have been

responsible in part for controversies over the

siting of a great many other technologies that

utilize the radiowave spectrum. Community resistance to the siting of radar installations,

broadcasting towers, and high-voltage transmission lines, for example, has been particularly strong and unexpectedly effective.

Citizens groups have actively opposed transmission lines in a number of States including

Oregon, New Hampshire, lowa, and Montana .

140 As a result of public action in New

York, the State Public Service Commission has

expanded the minimum right-of-way for new

lines and established an Administrative Research Council to study and assess health

risks.”’ The legislatures of a few New York

counties have adopted resolutions opposing

the construction of 765 KV lines. ’42 In Minnesota, farmers battled with the public utilities

over the construction of a powerline through

8,000 acres of prime farm land. ’43 After attending public hearings and installing solar and

wind devices in their homes to reduce their dependence on the utilities, some became frustrated with what they perceived as the unresponsiveness and dishonesty of the utilities

and finalIy resorted to demonstrations, destroying utiIity towers and equipment.

The siting controversies most relevant to the

SPS microwave systems are the disputes over

the Navy’s Project SEAFARER (Surface ELF*

Antenna for Addressing Remotely-Deployed

Receivers), a 25,600-mi 2 underground radio

antenna for communication with nuclear submarines; and the Air Force’s PAVE PAWS (Precision Acquisition of Vehicle Entry Phased Array

Warning System), a radar system.’” When the

Navy attempted to locate SEAFARER at different times in Wisconsin, Texas, New Mexico,

Nevada, and Michigan, it encountered vehe140’’ The New Opposition to High-Voltage Lines, ” Business

Week, November 1977

‘41A. Marino and R Becker, “H Igh Voltage Lines. Hazard at a

Distance,” Environment, VOI 20, No 9, p 6-15

‘“K Davis, “Health and High Voltage, ” Sierra C/Ub 6u//etin,

JulV 1, August 1978

14’H Nuwer, “Minnesota Peasant’s Revolt, ” Nation, VOI 227,

Dec 9, 1978

* E 1 F (extremely low frequency) radio waves

’

44P Flrodeur, The Zapping of America, Their Deadly Risk and

Cover-[/p (New York W W Norton & Co , 1977)
260 ● Solar Power Satellites

ment local opposition. Residents in these communities were concerned about the health hazards of ELF radiation. Ranchers in Texas were

also worried about the effects on livestock.

Opponents raised other issues including vulnerability to nuclear attack, private property

rights, and decreased land values. 45 Referenda

defeated SEAFARER’s construction in several

counties in Michigan, and in an unprecedented

action, the Governor of Michigan rejected the

military program. 146 The Governor of Wisconsin also accused the Navy of suppressing environmental impact studies that reported

possible environmental and health hazards. 147

Although the ELF program is still being funded,

it has yet to find a new site.

Legal action has also been taken against the

Air Force’s plans to build PAVE PAWS in Cape

Code, Mass., and Yuba City, Calif. 148 Fear of

adverse microwave bioeffects, especialIy longterm, low-level effects, sit at the heart of the

controversy. While the Air Force stressed that

health risks were negligible and emphasized

the need for national security, local groups

argued that the data did not support the claim

that PAVE PAWS will not jeopardize their

health.

149

Several key observations can be made from

these disputes. First, farmers, ranchers, and

rural Americans are becoming an increasingly

active social force working against the intrusion of urban America on their rural quality of

life. As one OTA workshop participant familiar

with powerline siting controversies remarked,

“Developers say that high voltage transmission

lines wouldn’t make any more noise than a

highway would and the reaction of people is

‘What do you mean? –That’s why we’re out

here. We don’t want to be near the highways’ . . , . (Rural Americans) are sacrificing

the kind of life they are out therefor, for the

energy excesses of urban America. 150 In many

‘“c Ellis, “Sanguine/SEAFARE R,” Sierra C/ub Bu//etin, VOI 61,

No 4, April 1976

“’Brodeur, op clt

1 4 7S Schiefelbein, “The Invisible Threat, ” Saturday Review,

Sept 5,1979, pp 16-20

‘

40 Brodeur, op cit

‘4’S. Kaufer, “The Air Pollutlon You Can’t See, ” New Times,

Mar 6,1978

““Office of Technology Assessment, op clt

cases, communities would prefer to leave a

site overgrown than consent to any kind of

development. For SPS as well as other powerplants, dumps, mines, and military installations, siting in remote areas could be a difficult task, especially in parts of the country

where residents have already mobilized

against other large-scale projects.151 According

to another workshop participant, one farmer,

when asked about the SPS proposal, responded, “I’ve had enough. I’m ready to get

my gun out.”152

Another factor that emerges from siting controversies is that while concerns over the environmental and health risks of a technology

are very important to nearby residents, this

issue may mask related concerns such as unsightliness and devaluation of local property

vaIues 153 that may be more important to the

Iocal community. For example, in the Minnesota powerline dispute, the fundamental

issue for many of the farmers was the question

of land-use, i.e., farmland v. right-of -way. ’54

However, this issue was channeled into environmental and health concerns that had

greater political leverage in the courts and to

which the utilities and the general public were

more responsive. While the health effects of

ELF radiation were the most frequently articulated concern of communities opposing

SEAFARER, it is clear that to some residents,

economics really lay at the heart of the controversy 155 These people were primarily concerned that Iand values might decrease if

potential buyers worried about the health effects, and might not have opposed the siting if

they had been justly compensated. Other residents were most concerned that the presence

of SEAFARER would make their land more

vulnerable to military attack; this would

threaten their safety and could also reduce the

vaIue of their land.156

‘‘I blci

‘)lbld

5

‘1 bld

‘“1 bld

“$joseph Thlel, Texas State Department of Health, privat e

cc]mmunlcatlon, Nov 28, 1979

‘“P Boffey, “Project SEAFARER Critics Attack Nationa l

A( ademy s Review Group,” Science, VOI 192, June 18, 1976, pp

121 )-1 21 -i
Ch. 9—institutional Issues ● 261

This second observation also points to the

complex interrelationship between environmental and health risks, costs, land and air use,

private property rights, esthetics, and public

control over local decisions. For SPS, it is clear

that the choice of transmission frequency and

power distribution as well as public radiation

standards could have a great bearing on the

area of land that would be required as a buffer

zone, the number of people potentially affected, compensated, and/or relocated, and

hence the cost of developing SPS. In addition,

the size of each SPS unit and its location could

determine the extent, number and therefore

cost of transmission lines that would have to

be sited. The cost of a proposed energy facility

such as SPS can also be increased if developers

do not solicit public participation and disputes

and court battIes delay construction. Siting

should therefore be considered as early as

possible in the development process; public input is an essential element in the development

and design strategy.

Finally, it is clear that many of the siting

disputes might have been resolved earlier and

more easily if the channels of communication

between developers and the local community

had been more open. Public participation

should be solicited whenever and wherever

possible, ideally even before the siting stage.

Too often, residents become frustrated and resentful towards developers and officials who

make inadequate and occasionally dishonest’

attempts to involve the public in meaningful

decisionmaking. This practice has led the public to seek other forums to voice complaints,

thereby delaying decisions and driving up

costs. SPS developers must be well-informed

about the environmental, economic, and military implications of SPS and shouId arrange for

open dissemination and discussion of that information. In addition, no matter what objective research findings are, public perceptions

of potential hazards are largely influenced by

public confidence (or lack thereof) in “official” interpretation of that data (see Environment, Health, and Safety). Whether justified or

not, the public is considerably more cautious

and fearful of the biological effects of

microwaves and other electromagnetic radiation than are many representatives of Government and industry. But until the uncertainties

are resolved to the public’s satisfaction, the

past cases strongly suggest that local resistance to SPS receivers could be substantial.
APPENDIXES
Appendix A

ALTERNATIVES TO THE

REFERENCE SYSTEM SUBSYSTEMS

Solar-Thermal Power Conversion

The basic operational principle involved in solarthermal-electric power systems is identical to that

of virtually al I conventional ground-based powerplants, with a solar furnace replacing the fuel-fired

furnace or nuclear reactor normally used to heat

the power-cycle working fluid. The 10-MW demonstration plant at Barstow, Calif., is such a solarpowered thermal cycle. Virtually all components

of such power systems have been extensively used

and/or tested on Earth, and hence solar-thermal

systems for potential space applications in the SPS

time frame would enjoy the availability of a large

body of applicable technology, hardware, and experience. Significant problems are foreseen, however, in reducing the mass and complexity of spacebased powerplants to levels that make them competitive with the reference system photovoltaic

power source.

The basic rationale for considering thermal

power cycles is their inherently high energy conversion efficiency. High-performance thermal cycle

power generators on Earth routinely attain overall

efficiencies of more than 40 percent, as compared

with the 17-percent projected efficiency for the reference-system photovoltaics, and it is quite probable that material and component developments

during the next decade or two could extend overall

operational thermal-cycle efficiencies for terrestrial units to over 50 percent. Unfortunately,

however, the space environment is such that these

efficiency levels, even with advanced-technology

power-conversion hardware, are extremely difficult

to achieve. The fundamental problem is that of

heat rejection; that is, in accordance with the dictates of the Second Law of thermodynamics, it is

necessary that any heat engine reject to its environment some of the energy it receives (the ubiquitous

“thermal pollution” of Earth-based powerplants).

On Earth, effective heat rejection at the low temperatures needed for high thermal efficiency is

readily accomplished by using vast quantities of

cool water or air. In space, on the other hand, all

heat rejection must be accomplished solely by

radiation, a process that depends on the fourth

power of the radiator’s temperature. Hence efficient heat rejection in space can be accomplished

only at high temperatures, which by the Second

Law results in reduced thermal efficiency. The radiators of the space-based thermal powerplant

therefore become the key limitation on performance, and counteract the beneficial effect of

potentially high-cycle efficiency. The most effective space-based thermal power cycle, then, is generalIy the one that minimizes the radiator mass.

The Brayton and Rankine Cycles

The two “simple” solar-thermal cycles considered for SPS are the Brayton and Rankine

cycles—the cycles used on Earth for gas turbines

and steam turbines, respectively. In the Brayton cycle, a compressor compresses a gaseous working

fluid, that is then heated by solar energy concentrated into an “absorber” by large, diaphanous

thin-film solar mirrors having a concentration ratio

of perhaps 2,000-to-l, then discharges its waste

heat to a radiator. It then returns to the compressor

and repeats the cycle.

The Rankine cycle utilizes the same basic energy

source as the Brayton cycle —typically, a 2,000-to-l

solar concentrator mirror focused on an absorber

– but employs a condensable liquid, or, frequently,

ordinary steam. The solar energy impinging on the

absorber boils and superheats the steam, which

then drives a turbine. The steam then condenses in

the radiator at constant temperature. The condensed water is then pumped back up to high pressure

and forced into the boiler (absorber) to complete

the cycle.

The Brayton and Rankine cycle options were rejected for the reference system, despite their

relatively high efficiencies, because of the high

radiator mass, the lower projected reliability of

rotating machinery, and relative complexity of orbital assembly operations as compared with the

photovoltaic options. However, recent developments in high-temperature heat exchangers and turbines, 1 and particularly innovative designs of heatpipe and other radiators2 3 now make Brayton-cycle

turbines more attractive.

“’Review Study of a 13rayton Power System for a Nuclear Electr!c

Jpace( raft, j PL contract 955W08, Garrett-AlResearch report No 31-

1288A ()( t 9, 1979

‘Yale C F astman, “A Study of the Appl Icatlon of Advanced Heat Pipe

Technology to Radiators for Nuclear Spacecraft, ” Thermacore, Inc , Lanc a~ter Pa E)ec 1, 1975, a I so see Ya Ie C E astm an, ‘‘Advanced Heat PI pes

[n Aero$pace Power System s,’ A IAA paper No 77-501, St I. OUIS, Mo , Mar

I -1, 1977

‘)ohn Hedgepeth and K Knapp, “Preliminary Investlgatlon of a Dust

Radiator tor Space Power System s,” Astro Research Corp report No ARCrN 10’14 Mar 1978

2 6 5
266 ● Solar Power Satellites

Other Thermal Cycles

Other thermal cycles have also been considered, 4 5 to be used independently or in conjunction with the Brayton or Rankine cycles in

a combination. The most Iikely prospects are

the thermionic6 7 and the magnetohydrodynamic

(MHD )

8 cycle s or the wave-energy exchanger. 9 10 11 12 13

None of these seems particularly well adapted

for use in an independent mode in space, although

any one of them may have potential when used in

combination with either the Rankine or Brayton cycle. The primary consideration for these cycles is

the tradeoff between high efficiency and high

radiator mass. Principal areas requiring research

and/or additional development are in the hightemperature solar collection and absorption portions of all systems and high-performance heatrejection devices, as well as extensive testing and

pilot operations to establish the required levels of

reliability and reductions in cost uncertainties.

Photovoltaic Alternatives

Alternative Materials

Alternative photocell materials considered before selecting the reference system options of

single-crystal silicon and galIium aluminure-arsenide were amorphous silicon, polycrystalline silicon, cadreium suIfide, copper iridium selenide, and

polycrystalline gallium arsenide. Although all these

‘Daniel L Gregory, “Alternative Approaches to Space-Based Power

Generation, ” /ourrra/ of Energy 1, March-April 1977, pp 85-92

‘Wllllam P C Ilbreath and Kenneth W Billman, “A Search for Space

Energy Alternatives, ” In “Radlatlon Energy Conversion In Space, ” Progres~ In Astronaut/c$ & Aeronautics, vo/ 61, Al AA, N Y , ] uly 1978, pp

107-125

‘G O , Fitzpatrick and E j Brltt, “Thermlonlcs and Its Appllcatlon to

the SPS, ” Ibid, pp 211-221

‘(For example), W Phllllps and J Mondt, “Thermlonlc Energy Conversion Technology Development Program, ” Progress report No 630-36 (for

June-September 1978), Jet Propulsion Laboratory, Pasadena, Callf , Nov

15, 1978

‘C V Lau and R Decher, “MHD Conversion of Solar Energy, ” In

“Radlatlon Energy Conversion In Space, ” K W Blllman (ed ), Progress In

Astronautics & Aeronautics, vo/ 61, Al AA, N Y , July 1978, pp 186-200

“Robert T Tausslg, Peter H Rose, John F Zumdleck and Abraham

Hertz berg, “Energy Exchanger Technology Applied to Laser Heated

Engines, ” Ibid, pp 465-478

1(’W E Smith and R C Weatherston, “Studies of a Prototype Wave

Superheater Faclllty for Hypersonic Research ‘ report No HF-1056-A-I,

contract AFOSR-TR-58-I 58, AD207244, Cornel I Aeronautical Laboratory,

Buffalo, N Y , December 1958

“Abraham Hertzberg and Chan-Veng Lau, ‘A High-Temperature

Ranklne Binary Cycle for Ground and Space Solar Appllcatlons, ” In

“Radiation Energy Conversion in Space, ” K W Blllman (ed ), Progress In

Astronautics & Aeronautics, vo/ 61, Al AA, N Y , July 1978, pp 172-185

“Arthur T Mattlck, “Absorption of Solar Radlatlon by Alkali Vapors, ”

Ibid, pp 159-171

‘ ‘A jay Palmer, “Radlatlvely Sustained (“eslum Plasmas for Solar E lectrlc Conversion,” Ibid, pp 201-210

materials cost less than either of the two selected

materials, their efficiencies are low and there is little experience in their production. Other factors

considered by the National Aeronautics and Space

Administration before selecting the two reference

system options were total system mass, materials

availability, susceptibility to radiation damage,

development status, manufacturing processes, and

energy payback. Other potential photovoltaic

materials that were rejected due to obvious problems with one or more of the above factors include selenium and various selenides, cadmium

telluride, copper sulfide, gallium phosphide, iridium phosphide, and a number of higher order inorganic compounds.

Concentration

Another important parameter is the concentration ratio (CR). The selection of CR = 2 for the

reference-system gallium arsenide option was

strongly Influenced by cell temperature considerations.14 Should cell technology develop that would

retain high efficiency at elevated temperatures,

higher concentrations might prove cost effective,

since both the mass and the cost of reflector

materials are considerably less than those of

photocelIs.

There is good experimental evidence that the

gallium aluminum-arsenide/gal lium-arsenide cells

selected for the SPS could utilize much higher concentration ratios to gain higher overall efficiency.

There has been considerable development in concentrating photovoltaic subsystems for terrestrial

use during the past 2 years, and it is possible that

passive rather than active cooling may be possible.

Multicolor Photocell Systems

Photocells respond to only a part of the available solar spectrum that impinges on them. It is

possible to achieve more efficient utilization of the

solar spectrum by: 1 ) manufacturing a single photocell from various materials, each responding to a

different wavelength band;15 or 2) using separate

celIs, each optimized for a different spectral region

and using an optical system to split the incident

light into the corresponding spectral ranges.

‘1 W Iame$, and R L Moon, “CaAs Concentrator Solar Cells, ” Procee(lIrtw 01 /he I T th Photovo/talc Specfa/lsts Conference, 1975, pp

40,? 408

Richard j Stlrn, “Overview of Novel Photovoltaic Conversion Techniq~i IPS at H Igh I ntenslty Level s,” In “Radlatlon Energy Conversion In

~pal e K W Blllman (ed ), Progress In Astronautics & Aeronautics, VOI

fl / I Uly 1978 pp 136-151

‘‘ I aan, ] url~~on, “Multlcolar Solar Cel I Power System for Space, ’r Ibid,

pp 1 5/! 158
Appendix A—Alternatives to the Reference System Subsystems ● 267

Although the technology for both approaches is

known, it is far from having been proved practical,

and will require considerable research and development effort before being considered for future

operational systems. The second approach appears

to be the most promising in principle. However, it

suffers from a lack of basic data on the photovoltaic materials that might be used for it. Despite

their attractiveness from the standpoint of efficiency, both systems also require either higher

mass or concentrator systems, which may require

active cooling. Again, vastly more research is

needed to determine the overall effectiveness of

these concepts.

Alternative Microwave

Power Converters

I n addition to the klystron, several other devices

may be capable of converting satellite electric

power to microwaves and transmitting them to

Earth. The solid-state amplifier, based on semiconductor technology, could result in a significant and

beneficial change of the entire system. The latter

serves as one of the four systems considered in this

assessment.

Crossed-Field Amplitier. Thls device in the ter m

of an “amplitron, ” was originally suggested for

the reference system in place of the klystron

(linear beam amplifier). Another form of this device, the magnetron, appears to have considerable merit, * particularly in reducing the spurious

noise and harmonics generation of the

microwave antenna. I n smaller form (1 kW), this

is the familiar unit that powers microwave ovens.

The latter devices are reliable and cheap.

Whether working devices of the 70-kW capacity

needed for the reference system antenna will

prove to be cost effective and possess the required signal characteristics must await design

and testing, individually and in a phased array.

So/id-State Devices. The principal motivation for

considering solid-state devices” is their extremely

high reliability;17 18 projected failure rates are

100 times lower than those of the reference-system vacuum-tube klystrons or amplitrons.19 A

secondary advantage of solid-state devices is

their potential for lower mass per unit area than

*W C Brown, Microwave Beamed Power Technology Improvement

PT-5613 J PL contract 955-104, May 1980

“G M Hanley et al , “Satelllte Power Systems (SPS) Concept Deflnltion Study, ” First Performance Review, Rockwell International report No

SSD79-0163, NASA MSFC contract NAS8- 12475, Oct 10, 1979

‘

nGordon R Woodcock, “SolId-State Microwave Power Transmitter Re

view, ” Boeing Aerospace Co DOE SPS Program Review, June 7, 1979

‘Vlbid

the vacuum-tube devices. Further, their small

size and potentially low unit cost facilitate convenient research and development activities.

The basic problem with solid-state devices is

their low-temperature capability, which implies

low power, coupled with their low-voltage output. Additional potential problem areas are uncertain efficiency, current high cost for high-performance units, and a host of as yet unresolved

transmission, control, and power distribution

complexities.20 However, these devices are still

in the early stages of being evaluated for the SPS

application, and it is Iikely that studies of the extent devoted to vacuum-tube devices during the

past few years can reduce the present uncertainties associated with sol id-state power conversion

and transmission.

A major area for concern with the solid-state

devices is the paucity of data and experience on

phase control. Although the same generic type of

retrodirective control is projected as for the

reference system, much research, analysis, and

technology advancement will be needed to

define its phase control capabilities to the

necessary level of confidence.

Photoklystrons

The photoklystron combines the principles of a

conventional klystron transmitting tube and the

photoemitter in a single device. Sunlight falling on

a photoemissive surface generates a current of

electrons oscillating in such a way as to emit radio

frequency electromagnetic waves. If used on the

SPS, the resultant microwaves could be beamed to

Earth by using a resonator waveguide.

Potential advantages of the photoklystron over

the photovoltaic array/klystron are that it could increase the useful portion of the photoelectric

energy spectrum as compared with photovoltaics

(it may reach efficiencies as high as 50 percent21 as

compared with 15 to 20 percent for conventional

photovoltaics), and that it would greatly simplify

the entire space segment of the SPS22 as compared

with the reference system, by (a) eliminating the

solar celI arrays altogether, (b) eliminating the need

for on board power distribution, (c) eliminating the

rotary joint and sliprings, (d) reducing the individual klystron power and heat dissipation requirements (there would now be many more klystrons

‘(’lbld

‘‘C Ibraeth and Blllman, op c[t

“}ohn W Freeman, Wllllam B Colson and Sedgwick Slmons, “Ne w

Method\ for the Conversion of Solar Energy to R F and Laser Power, ” In

Space ‘danufacturlng 1 I l,’ Jerry Grey and Chrlstlne Krop (eds ) Al AA,

New York November 1979
268 ● Solar Power Satellites

distributed over a much larger area), thereby increasing the lifetime of individual klystrons, (e)

reducing individual klystron cost, and (f) reducing

rectenna area requirements, since the transmitting

antenna is much larger than that of the reference

system.

One suggested system (fig. 10) consists of a large

elliptical array of photoklystrons, constituting the

collector and antenna. A large mirror (that could

also be a concentrator) would reflect sunlight to

the photoklystrons. Note that even though the mirror and antenna must rotate with respect to each

other to maintain proper Sun-facing and Earthfacing attitudes, as in the SPS reference system,

there is no need for a mechanical connection between them; in fact, their relative alinement is not

at all critical.

Small working models of photoklystrons exist,

but have not yet demonstrated any of the system

characteristics needed for a practical and cost- effective SPS. Hence the concept still remains just

that: a highly interesting and promising prospect

for further intensive study.

Offshore Rectennas

Because siting a rectenna near the coastal population centers that will have most of SPS-generated baseload electricity may prove extremely difficult, it has been suggested that rectennas be

located in shallow offshore waters. * The costs of

such siting would certainly be higher for a given

area than for comparable land-based sites, but the

system costs might be cheaper overall because of

cost reductions in rectenna size. The considerable

body of relevant experience that was developed for

offshore airports would be useful for studying this

possibility. The land areas that have been considered for offshore airports are comparable to the

needs of SPS rectennas (e. g., 50 to 20 kmz).

It may be possible to reduce the necessary area

of an offshore rectenna by eliminating most of the

buffer zone and “flattening” the power distribution

of the beam across the rectenna. Though potentially costly, the option may be taken very seriously by

the European community for whom rectenna siting

on land would prove most difficult. It may also find

uses along the shores of densely populated areas in

the United States.

‘Rice Unlverslty, Solar Power Satelllte Offshore Rectenna Study NASA

CR 1348, November 1980
Appendix B

DECENTRALIZED PHOTOVOLTAIC MODEL

Estimating the busbar costs for a house or industrial plant power station, whether connected to

the grid or stand-alone, may involve somewhat different assumptions than for a central power station. For one thing, the homeowner’s access to capital is different than that of the utility. In addition,

the tax liabilities are different and arise from a different conceptual framework.

In order to compare most directly the busbar

costs of a decentralized photovoltaic technology

with the centralized terrestrial case and with the

solar power satellite, OTA has adopted the case of

decentralized systems leased by a utility to an individual owner. The choice to calculate the costs

this way represents neither a preference nor a prediction on the part of OTA for the way in which dispersed photovoltaic systems will be marketed in

the future. The costs so calculated are the costs to

the utility and do not reflect the price to the consumer. They therefore are directly comparable to

the busbar costs of electricity from the solar power

satelIite.

For homeowners who would prefer not to continue to rely on a central structure for their power,

leasing equipment from a utility may not be an acceptable arrangement. Many, however, will not

wish to accept the relatively high capital investment and subsequent maintenance which an in

stallation requires and wilI prefer leasing to purchase.

Household and Industrial Photo voltaics:

costs and efficiencies

System assumptions:

Array efficiency–18 percent*

Degradation – 5 percent first year, stable thereafter

Systems life– 30 years*

Inverterefficiency—90 percent

Battery efficiency– 75 percent round trip

Array cost — $35 m2

*

Additional installation costs assuming roof replacement — $0.0

Additional installation costs assuming array flat on

roof — $1 3/m 2

Additional installation costs assuming array on ground –

$80/m2

Operation and maintenance–1 percent of initial costs

per year

Lightning protection:

Household – $500

Industry– $0

Inversion and power conditioning–$82/kW

Battery lifetime (deep cycles) –2,000

Battery initial costs ($/kWh capacity)–$49/kWh

Battery O&M cost (¢/kWh discharged) –O.038¢/kWh

Battery total cost (¢/kWh discharged): 4.3¢/kWh

Battery housing and related costs ($/kWh capacity)–

$6.4/kWh

Backup generator, residential –$306/kW

Industrial cogenerator steam turbine–$1,446/kW

Percent backup in system with storage–60 percent

Sample Calculation

The following equations apply, assuming there

are no variable O&M costs and no fuel costs.

Busbar costs (¢/KWh) = Ievelized capital cost/levelized

output + Ievelized fixed O&M/levelized output

Levelized capital cost = FCR X initial capital cost

($/100m2

) x 100 ¢/$

FCR (fixed charge rate)= CRF (i/N) + T

CRF (i/N) = capital recovery factor = 1

1-(1 + i) – N

where:

I =

N =

T =

TD =

weighted cost of capital

economic life = book life

Ievelized income taxes =(t/(l-t))(CRF( i/N) -1)

x P – (TD – 1/N)

tax alIowance for accelerated tax

depreciation**

CRF (i/N) x ((2 x (M – (1/CRF(i/M)))/(M X

(M+ 1)X i))

M = tax life

Levelized output = kWh/year/100m2 array

Levelized fixed O&M= O&M($/100m2/yr)X1000/$ X

AF(e,i,N)

AF(e,i,N) = CRF(i/N) X (1 – ((1 + e)/(1 + i))N)/(i – e)) X

(1 + e)

where e = apparent escalation rate (inflation rate)

Financial assumptions:

I = 0.1 0

t = 0.30

e = 0.06

N = 30 years for array

= 6 years for batteries

M = 20 years

Example–

A household 100m2 array mounted on the roof in

Boston generates 22,017 kWh/yr:

Cost of array .$3,500

Lightning protection $ 500

Power conditioning ., ... $ 650

Structural support ., .. $1,300

Total ... ., .$5,950

‘Assumptions of SPS reference system

83-316 0 - 81 - 19

* *A~sume\ sum-of-the-years dlglt~ depredation method

269
270 • Solar Power Satellites

O&M costs/year = 1 percent capital costs = $59.56

FCR = 0.12504

Levelized capital cost= 0.125 X 5,956 X 100

= 74,450 ¢/l00m2

/year

Levelized fixed O&M = 9,705 ¢/100m2

/year

Busbar costs (¢/kWh) =

74,450 —— + 11,233 = 3.9¢/kWh

22,017 22,017
Appendix C

GLOBAL ENERGY DEMAND FORECASTS

1. IIASA’s predictions were influenced by several factors: 1 ) most of the analysis was done prior to

the 1979 rise in oil prices; 2) there was an optimistic view of the growth of nuclear capacity (to

some 50 to 60 percent of global generating capacity by 2030); 3) participation in the study by

the Soviet Union and other centrally planned economies, who for political reasons projected

very high economic and energy-use growth rates; 4) low expectations for conservation and

alternative energy sources.

2. Predictions of future energy demand are based on estimates of underlying economic and

demographic factors, and of the relation between overall economic and population growth and

energy demand. IIASA’s population and GDP growth rate projections are as follows:

Population projections by region, high and low scenarios (10’ people) (Finite World, p. 429)

Population base

Region year 1975 Projection 2000 2030

I (NA)-North America 237 284 315

II (SU/EE)-Soviet Union/East Europe ........, 363 436 480

Ill (WE/JANZ)-West Europe/Japan, Australia 560 680 767

Iv (LA)- Latin America 319 575 797

v (AF/SEA)-Southern Africa& Asia .......... 1,422 2,528 3,550

VI (ME/NAF)-Middle East/North Africa 133 247 353

Vll (C/CPA)-China/Central Planned Asia 912 1,330 1,714

World . 3,946 6,080 7,976

NOTES: 1975 data are mldyear estlmates from Unlted Nations Monthly Bulletin of Statistics Januar~ 1978

Historical and projected growth rates of GDP, by region, high and low scenarios (percent/yr)

High scenario

Historical Scenario projection

Region

I (NA )

II (SU/EE) .

Ill (WE/JANZ )

Iv (LA )

v (AF/SEA) .

VI (ME/NAf )

Vll (C/CPA)

World

I + Ill (OECD).

IV + V(Developing)

1950-60

3.3

10.4

5 0

5.0

3 9

7 0

8.0

5.0

4.2

4 7

1960-75 1975-85

3 4 4 3

6 5 5.0

5 2 4 3

61 6 2

5 5 5 8

9 8 7 2

61 5 0

5 0 4 7

4 4 4.3

6.5 6.3

1985-2000

3 3

4 0

3 4

4 9

4.8

5.9

4.0

3 8

3 4

51

2ooo-15

2 4

3 5

2 5

3 7

3 8

4 2

3 5

3 0

2.5

3 9

2075-30

2 0

3 5

2 0

3 3

3.4

3 8

3 0

2 7

2 0

3 5

Low scenario

Historical

Region 1950-60

I (NA ) 3.3

II (SU/EE). 10.4

Ill (WE/JANZ). 50

Iv (LA ) 5.0

v (AFI/EA ) 39

VI (ME/NAf) 70

Vll (C/CPA) 8.0

World 5 0

I + Ill (OECD) 4 2

IV + V + VI (Developing) 4 7

1960-75

3 4

6 5

5 2

6.1

5 5

9.8

61

5 0

4 4

6 5

Scenario projection

1975-85 1 985-2000 2000-15 2015-30

31 2 0 11 1.0

4 5 3.5 2.5 2 0

3 2 2.1 1.5 1.2

4 7 3.6 3 0 3 0

4 8 3 6 2 8 2 4

56 4.6 2 7 21

3 3 3,0 2 5 2 0

3.6 2 7 1 9 1 7

3.1 21 1 3 11

5.0 3 8 2 9 2 6

SOURCE Energy In a F/n/te World, A Global $ystems Ana/ys/s, Energy Systems program croup lnt~matlonal In$tltute for Applied svstems Analvsls (Cambridge,

Mass Balllnger Publlshlng Co , 1981) p 431

271
272 ● Solar Power Satellites

3. In general, the IIASA study places great emphasis on the development of nuclear power, and

especially on an explosive growth in fast breeders after 2000. Although a number of countries,

including France, Japan, and the Soviet Union, have announced aggressive plans to install

breeders over the next several decades, it should be remembered that questions still remain as

to breeder reactor safety, reliability and operating costs. (See ch. 6 for a comparison of

breeders and other baseload power sources.) IIASA’s high expectations for breeder development are by no means universalIy shared.

Percent of global secondary electrical demand met by nuclear power–llASA

1975 2000 –2030

Low High Low High

Conventional reactors 2 0 271 294 19,2 22.9

Breeder s 0.0 044 067 40,6 38,2

Total 20 275 303 498 611

SOURCE Energy in a Finlte World, p 580

4. These higher estimates for the amount of coal used for synfuels depend on a number of

assumptions, including the greatly increased use of nuclear power to replace coal in electricity

generation.

5. The following CONAES study estimates for the U.S. should be compared with the IIASA

estimates for North America (see No. 1, p. 271 for population and economic figures; assume

Canadian population is approximately 10 percent of total),

Population in 2070—279 million (Bureau of Census Series I I projection, with no allowance for illegal immigration). z

Average growth in GNP, 1980-2010—2 percent per year ]

Primary energy demand (Quads)

CO AfAES4 [United States on/y - 2010)

Low [A] Medium [B] High (C)

70 90 130

IIASA5 (North America-Canada approximately 10 percent of total)

2000 2030

Low 99 131

Hig h 120 180

Direct comparisons are difficult because of the different time frames and geographical areas

examined. The CONAES A projection, no growth in energy demand over the next 30 years, has

no parallel in the IIASA study. The IIASA low scenario is slightly higher than the CONAES series

B projections; the high scenario is approximately equal to CONAES C. Population estimates are

compatible; however, CONAES’ 2 percent per year average GNP growth rate is much lower

than IIASA’s high scenario. It is approximately equal to the low scenario forecast.

Insofar as the two studies are comparable, CONAES’ estimates are somewhat lower than

IIASA’s, with the more radical CONAES A projection much lower. The difficulty lies in determining what this might mean on a global scale. Lower estimates for the United States may hold

true for other Western industrialized areas, but cannot be extended to developed centrally

planned economies or to the developing world, where growth rates are expected to be higher

than in the OECD. The CONAES report itself states that: “Even if energy conservation in the

United States accomplishes a great deal domestically, it will be more than offset by demand

growth in countries at the ‘takeoff’ stage of development “ Global energy consumption in 2010

is estimated to be probably three to four times what it is now, with electrical consumption

rising at even faster rates. b

6. The Case Western Reserve and World Energy Conference estimates for future energy and electricity use are as follows:

‘Energy In Transltlon, 1985-2010 (Washington, D C , National Academy of S, Iences, 1979), p 626

z I bid , p 643

‘Ibid , p 645

‘1 bid , p 668

‘Energy In a Ftnfte VVor/d A G/oba/ Systems Ana/ysls, Energy Systems Progr~m Group, I nternatlona I I nstltute for Appl led Systems Analysis

(Cambridge, Mass Ballinger Publishing Co , 1981), p 44o

‘Energy In Transition, p 626 )
Appendix C—Global Energy Demand Forecasts ● 273

Energy demand (Quads

20

60

40

20

0

20

40

60

1975 2000 2025/2020

CWRU WEC C WRU WEC

OECD . . . . ... 146.8 3453 266.2 618,8 395.1

SU/EE . . . . . . . . . . . . 55.0 98.3 126,1 205.7 235.0

Developing, ....,... 37.7 103.0 174.0 296,8 434.2

Global. . . . . . . . . 239.5 5466 566.3 1,121.3 1,064.3

End-use electricity demand (Quads electric) (estimated by Clav. and Dupas from model data)

1975 2000 2025/2020

CWRU WEC CWRU WEC

OECD ., 12,5 55.8 386 106,9 66.1

SU/EE : 3.9 152 216 353 353

Developing ., 1.8 102 135 40.2 465

Global, 18,2 812 737 182,4 1479

Compare these figures to the lower IIASA estimates in figure C-1. The worldwide distribution

of LEPP in 2025 for the CWR model is:

Figure C-1 .—Large Electric Powerplants in 2025

160 140 120 100 80 60 40 20 0 340 320 300 280 260 240 220 200 180

F

E

D

c

B

A

a

b

c

d

e

f

8 Nb per zone

 “Preliminary Evaluation of Ground and Space Solar Market in 2025, ” 29th IAF Congress, October 1978
274 ● Solar Power Satellites

7. The World Bank report on Energy in the DevelopingCountries projects energy use and demand

over the next decade. From 1973-78, growth in electricity consumption in developing countries

averaged 8 percent per year, compared to 3.5 percent in developed countries; the Bank estimates this will continue through the 1980’s. The Bank reports that in 1980 Oil-Importing Developing Countries (OIDC) invested $18.5 billion in electric power (70 percent for generation, 20

percent for distribution, 10 percent for transmission) out of a total of $24.6 billion invested in

all forms of energy—over 75 percent. This is expected to more than double, to $39.7

bilIion/year, by 1990.

The amount of installed capacity is estimated to be 241 gW in 1980, rising to 523.7 in 1990.

Large increases will be made in gas and nuclear fired generators though absolute levels will remain relatively low; hydro power will remain the largest single source, at approximately 40 percent of the total, with oil generation declining rapidly from 37 to 25 percent. ’

‘Energy In the Deve/op/ng Countrle>, World Bank, August 1980, pp 42-49
Appendix D

ENVIRONMENT AND HEALTH

DOE Comparative Environmental

Assessment

The Department of Energy (DOE) has sponsored

comparative environmental assessments between

the following energy technologies: conventional

coal (CC), coal gasification/combined cycle (CG/

CC), light water reactor (LWR), liquid metal fast

breeder reactor (LMFBR), magnetically confined fusion (MC F), central station terrestrial photovoltaics

(CTPV), and the reference system solar power satellite (SPS). An analysis was performed to quantify

and compare the effects of these technologies on

environmental welfare (i. e., effects that are not

directly related to health and safety such as weather modification, resource depletion and noise),

health and safety and resource requirements. Unquantifiable health impacts were also identified,

but were not ranked (see table D-l). The major conclusions include:1

With respect to effects on the environmental

welfare, all of the energy options except for

coal (because of CO2 climatic alterations and

acid rain) are roughly comparable in magnitude, while different in nature.

As shown in figure D-1, it is apparent that the

quantified public and occupational health

risks of all the technologies except coal are

about the same in magnitude, but different in

cause. The health effects that were not included in this analysis are Iisted in table D-1.

Land use comparisons indicate that the land

area required for SPS would be similar to that

for CTPV. Coal utilizes slightly less total land

area. This is distributed among many mining

‘Program Assessment Report, Statement of Flndlngs, Satell Ite Power

Systems, Concept Development and Evaluation Program, DOE/E R-0085,

November 1980

●

●

sites as opposed to the large contiguous land

space needed for SPS and CTPV. The nuclear

technologies require the least total land area.

While each technology would encounter material constraints, none appear insurmountable. Water requirements are listed in table

D-2.

All technologies considered are not energy

producers when operating fuel requirements

are excluded from the calcuIations. Otherwise,

only the inexhaustible technologies are net

producers.

Microwaves—Ionosphere Interaction

While only a small fraction of the incident

microwave energy is absorbed by the ionosphere,

the resultant heating at microwave frequencies

could significantly alter the thermal budget of the

ionosphere. In the lower ionosphere (D & E regions)

a phenomenon called “enhanced electron heating”

can occur if the microwave heating overwhelms

the natural cooling mechanisms of the ionosphere.

The resultant heating can then affect electron-ion

recombination rates, changing ionospheric densities, or drive additional interactions. Furthermore,

in the E region it is possible that the microwave

heating could enhance natural density irregularities called “sporadic E“ that can cause scintillations or scattering of radio frequency signals particularly in the very high frequency (VHF) band,

e.g., citizen-band and some television bands. z

New experiments and theories were needed to

understand the effects of an SPS microwave beam

traveling through the ionosphere (an example of

.—.

‘W E Gordon and L M Duncan, “Reviews of Space Science–SPS impacts on the Upper Atmosphere,” Astronautics arid Aeronautics, july/

August 1980, VOI 18, NoS 7,8, p 46

Table D.1 .—Unquantified Health Effects”

Solar technologies (CTPV, SPS) Nuclear technologies (LWR, LMFBR, MCF)

Exposure to cell production emissions and hazardous System failure with public radiation exposure (including waste

materials. disposal).

Chronic low-level microwave exposure to the general and Fuel cycle occupational exposure to chemically toxic materials.

worker populations (SPS).

Exposure to HLLV emissions and possible space vehicle Diversion of fuel or byproduct for military or subversive uses.

accidents (SPS).

Worker exposure to space radiation (SPS). Liquid metal fire (LMFBR, MCF only).

atW unquantified health effects were identified for the coal SYStem used.

SOURCE: Program Assessment Report, Statement of Flnr)vrgs, Satellite Power Systems, Concept Development and Evaluation Program, DOEIER-0085, November 1980.

275
276 Ž Solar Power Satellites

Table D.2.—Water Requirements for

Alternative Energy Technologies

Cubic meters

Technology per gigawatt year

Conventional coal. . . . . . . . . . . . . . . . . . . . . . 77x 106

Light water reactor. . . . . . . . . . . . . . . . . . . . . 37x 10’

Liquid metal fast breeder reactor . . . . . . . . . 32X 1O6

Coal gasification/combined cycle. . . . . . . . . 14x 106

Magnetically confined fusion . . . . . . . . . . . . 39x 106

Satellite power system. . . . . . . . . . . . . . . . . . = 1 x 103

Central station terrestrial photovoltaics . . . = 1 x 104

SOURCE: Program Assessment Report, Statement of Findings, Satellite Power

Systems, Concept Development and Evaluation Program, DOE/

ER-0085. November 1980.

what is called “underdense” heating) because

almost all of the data generated in the past has

focused on the “overdense” case, i.e., where the

ionospheric density is great enough to reflect the incident heating frequency.

Two high frequency (HF) ground-based heating

facilities have been used to simulate SPS heating in

the lower ionosphere. At Arecibo, Puerto Rico,

ionospheric physics and heating mechanisms have

been studied. The Platteville facility in Colorado

has tested the effects on specific radio frequency

navigation and broadcasting systems, namely VLF

(3 to 30 kHz, OMEGA), LF (30 to 300 kHz,

LORAN-C), and MF (300 kHz to 3 MHz, AM).3 However, neither Arecibo nor Platteville is equipped to

generate a beam of SPS frequency and power density. Instead the experiments were performed at

lower frequencies and power densities and the

results extrapolated to SPS conditions using the

scaling law:

P SPS = 

P

——HF

f2 SPS f2 HF

where Psps and PHF are the power of the SPS beam

(i.e., 23 mW/cm2

) and heating facility beam respectively, and f is the frequency of the beam (i. e., fsps

= 2.45 GHz).4 This extrapolation is thought to be

valid only if the primary heating mechanism is

ohmic (i. e., heating by CoIIisions between ions). This

assumption has been verified over a limited range

of frequencies. By increasing the Platteville and

Arecibo power densities and maximum frequency,

confidence in the sealing theory could be improved. Experiments are also needed to test the effects of localized ionosphere heating on telecommunication systems operating at frequencies above

3 MHz.

In the upper ionosphere (F region), effects on

telecommunications and on the SPS pilot beam

stem primarily from a phenomenon called “thermal self focusing ” which results when an electromagnetic wave propagating through the ionosphere iS focused and defocused as a resuIt of normal variations in the index of refraction. As the incident wave refracts into regions of lesser density,

the electric field intensity increases. Thermal pressure generated by ohmic heating drives the plasma

from the focused areas, thereby amplifying the initial perturbation. Although the heated volume in

the D and E regions is confined essentially to that

of the beam, the heated particles in the F region

wiII traverse magnetic field Iines so that large-scale

field-alined striations or density irregularities form.

These striations reflect VHF and UHF radiowaves

specularly, causing interference and the abnormal

long-range propagation of the signals.

Less is known about the effects of SPS-type

heating in the F region than the D and E layers. The

power scaling law in the upper ionosphere may differ from that in the lower regions (i.e., the scaling

law for thermal self-focusing instability may follow

a 1/f3 dependence rather than the 1/f2 dependence

valid for ohmic heating). Experimental data is

Fnv/ronmental Assessment for the Satell/te Power System – Concept

Development and Eva/uatlon Program – Effects of /onospher/c Heat/rig on

Te/ecomm[/n[catlons, DOE/NASA report, DOE/E R 10003-TI, August 1980

‘t nv/ronmenta/ Assessment for the Sate//lte Power System – Concept

Det eloprrrenf and Eva/uat/on Program, DOE/E R-0069, August 1980
Appendix D—Environmentant Health . 277

needed to improve theory and test the effects on

telecommunications.

A single SPS would cause the indicated ionosphere perturbations within a VoIume approximately equal to the power beam dimensions. For muitiple SPS deployments (e.g., the 60 systems defined

in the Reference Design) the cumulative effects of

the perturbed volumes must be determined. One

important question obviously concerns the possibility of coupling between adjacent volumes, and

determining beam separation constraints to eliminate mutual coupling. 5

The Effects of Space Vehicle Effluents

on the Atmosphere

SPS reference system rocket exhaust products

would affect every region of the atmosphere. In

table D-3, the atmospheric effects of most concern

are listed. As part of its assessment, DOE has also

identified possible means of resolving these uncertainties in the event that an SPS program is pursued.

Troposphere 6

SPS launch effluents injected into the troposphere could modify local weather and air quality

on a short-term basis. These changes would be due

primarily to the formation and dispersion of a

launch site ground cloud that consists of exhaust

gases, cooling water, and some sand and dust.

While sulfur dioxide, carbon dioxide, and carbon

monoxide concentrations would not be significant,

nitrogen oxides and water vapor are of concern.

Nitrogen oxides (NOx, especially NO, in the

ground cloud, might under certain conditions, present problems for air quality. The projected ground

cloud concentrations themselves are not thought

to violate the short-term national ambient air quality standards that are expected to be promulgated

in the near future, but if ambient concentrations

are already high, a violation could occur. NOX and

SOX in the ground cloud could contribute to an increase in localized acid rain but this is expected to

be small.

The ground cloud will also contain about 400 to

650 tons of water. While having a negligible impact

on air quality, water vapor, especially in association with launch-generated heat and condensation

‘E Morrison, National Telecommunlcatlons and Information AdmlnIstratlon, private communlcatlon, Feb 17, 1981

‘Most of this section IS derived from Ertv/ronrnenta/ Assessment for the

Satell/te Power $ystem, Concept Development and tvaluatlon Program,

DO E/ ER-0069, August 1980

nuclei could have a measurable, although shortterm effect on weather. In particular, under certain

meteorological conditions, heat and moisture

could enhance convective activity, and induce

precipitation. While the frequency and degree of

such effects are uncertain, none of the projected

weather effects are thought to be serious. Cloudcondensation and ice-forming nuclei would also be

produced in the ground cloud. The effects of the

latter on weather cannot be reliably estimated at

this time. The high abundance of the former in the

ground cloud is thought to be meteorologically important; cloud-condensation nuclei could change

the frequency and persistence of fog and haziness.

It has been suggested that because of the large size

and frequency of HLLV launches, cumulative effects might occur. More research is needed not

only for SPS, but of weather and climate phenomena in general.

Research needs include:

●

●

●

●

refine and test ground-cloud formation and

transport predictive models as well as weather

and climate models,

update ground-cloud composition as systems

are developed; conduct appropriate observations of rocket launches,

study effects on local weather of prospective

launch sites including possible cumulative effects, and

consider NOX effects and possible ways to

reduce levels given a range of Iikely future

standard levels and meteorological conditions; refine and validate theoretical models

for simulating NOx dispersion,

Stratosphere and Mesosphere

The upper atmosphere has received considerable

public attention in the last decade, largely as a

result of a number of studies examining the effects

on the stratospheric ozone layers (which shield the

Earth from biologically harmful ultraviolet radiation) of the supersonic transport, fluorocarbons,

and the biological generation of nitrous oxide

etc. 7 8 There is concern that while the potential effects on climate and terrestrial life of altering the

upper atmosphere couId be serious, our understanding of the physics and chemistry of the region

is Incomplete. For example, it is known that the

chemical composition of the upper atmosphere

plays a key role in maintaining the Earth’s thermal

budget and is directly linked to the dynamics, cirThe Aero\ol Threat, ” Newsweek, Oct 7, 1974, pp 74-75

“( I Imatl( Impact Committee, NRC, Fnv/ronmenta/ Impact of $tra(o-

\phorlr I /IRh/ NAS, Washington, D C 1975
278 ● Solar Power Satellites

Known

Launch vehicles will inject large amounts of

water vapor and thermal energy into

localized regions of the planetary boundary

layer. The potential for inadvertent weather

modification under suitable meteorological

conditions exists.

Exhaust emissions and reentry products

from reference system heavy-lift launch

vehicles and personnel orbit transfer

vehicles will modify ion densities at high

altitudes. In particular, injection of H2O and

H2 in the F-region will cause partial

depletion of the F-region.

Ground clouds formed by HLLV launches

will contain relatively high concentrations

of NOX that, in combination with effluents

from sources in the launch site environs,

will exacerbate existing air quality problems

under certain conditions,

HLLV flights will deposit a large amount of

water and hydrogen above 80 km. The

globally averaged water content is likely to

be increased by amounts ranging from 8

percent at 80 km to factors of up to 100 or

more above 120 km. The injected water and

hydrogen will increase the natural upward

flux of hydrogen by as much as a factor of

2.

Table D-3.—Atmospheric Effects

Uncertainty

The frequency of occurrence of suitable

meteorological conditions. The extent of

injection of cloud condensation and iceforming nuclei. The duration and scale of

the effects of the nuclei and the thermal

energy inputs. The importance of

anticipated small increases in cloud

population, precipitation, haze, and other

meteorological effects to the environs of

the launch site.

Chemical-electrical interactions in the

ionosphere, the effectiveness of mitigating

strategies, and effects on

telecommunications.

Exact value of NO2 air quality standard to be

set. Actual ground-level concentrations of

NO2 associated with vehicle launches under

various ambient meteorological and air

quality conditions typical of anticipated

launch sites.

The quantitative increases. Whether the

globally averaged increase in water content

will be sufficient to alter thermospheric

composition or dynamics in a significant

way. Whether the increase will result in a

chronic, global-scale partial depletion of the

ionosphere of sufficient magnitude to

degrade telecommunications. Whether the

increased hydrogen flux will significantly

increase exospheric density and/or modify

thermospheric properties.

Resolution

Design and implement appropriate

observational programs associated with

rocket launches and conduct laboratory

Injection of water vapor from HLLV The scale and persistence of the clouds,

launches in the altitude range of about 80 especially in view of poorly understood

to 90 km is likely to result in the formation co m p et i n g cooling and h eating

of noctilucent clouds. mechanisms. Whether cumulative effects

could arise and lead to globally significant

effects such as changes in climate

Reference system personnel and cargo orbit Ultimate fate of effluents. Potential impacts

transfer vehicles would inject substantial such as increased radiation hazards to

amounts of mass and energy into the space travelers, auroral modifications,

magnetosphere and plasmasphere. telecommunications, and terrestrial utility

interference, enhanced airglow emissions,

and changes in weather and climate.

experiments to characterize better nuclei

formed in the combustion of rocket

propellant. Refine, test, and validate

theoretical models suitable for simulating

the effects of rocket launches. Examine the

meteorological conditions appropriate to

potential launch sites. Evaluate the

importance of changes in those conditions

to the environs of those sites.

Design and implement experiments aimed at

critical problems. Measure and analyze

interactions through rocket experiments

combined with telecommunications tests.

Apply results to improve theoretical

prediction capabilities. Provide guidance for

system operational mitigating strategies

and alternatives.

Utilize a range or anticipate probable

“standard values” for NO2 including the

existing standard for California. Refine,

test, and validate existing modeling techniques for simulating formation and

dispersion of NO2 in ground clouds. Utilize

existing and acquire new data related to

rocket launches for this purpose. Prepare a

climatology of expected NO2 ground-level

concentrations under a range of meteorological and ambient air quality conditions

typical of anticipated launch sites.

Obtain a better understanding of the natural

hydrogen cycle and develop and implement

models to simulate the effects of rocket

propellant exhaust on a global scale.

Design and implement observational

programs to obtain data on the occurrence

and characteristics of high-altitude clouds

formed during rocket launches. Improve

knowledge of the natural atmosphere near

the mesopause and develop and implement

models to better simulate the effects of

water and hydrogen injection on cloud

formation.

Design and implement experiments in the

magnetosphere to obtain data for improving

understanding of magnetospheric

phenomena of interest and provide system

design guidance where appropriate.

SOURCE: Program Assessment Report, Statement of Firrdmgs, Satellite Power Systems Concept Development and Evaluation Program, DOEIER-0085, November 1980.

—.— .

culation and climate of the troposphere, but the els 10 One dimensional models predicting global

mechanisms that couple the two regions are ex- average vertical transport of atmospheric constitutremely complex and not well understood. 9 The ents are used most extensively, although less-refinSPS assessment relies mostly on theoretical mod- ed two and three dimensional models are also

‘tncyc/oped/a of ‘ic(ence and Technology VOI 1 (New york McCrawHIII Book Co , 1977] “’~u~ra note b
Appendix D—Environment and Health ● 279

available. High-altitude experiments are needed to

improve atmospheric theory and the data base for

the SPS assessment.

The most significant SPS impacts would arise

from the injection of rocket effluents, especially

water vapor and reentry NOX directly into the

stratosphere and mesosphere. SPS vehicles emit

CO, into the upper atmosphere but the amount is

extremely small relative to existing levels and to

the quantities generated by the consumption of

fossil fuels. The effects of any impurities in the

rocket fuel, such as sulfur would be negligible.

Thermal energy is also injected by HLLV and PLV

launches, but the effects are thought to be minor

and transient.

Increases in water vapor would be of concern

because its natural abundance in the upper atmosphere is very low. The most recent estimates indicate that the increase in the globally averaged

concentration of water vapor due to 400 HLLV

flights per year would be about 0.4 percent in the

stratosphere (30 km) and 8 percent in the upper

mesosphere (80 km). 2 Increases near the latitudes

at which the water vapor was emitted could be

higher due to a so-called “corridor effect” with increases in water content up to 15 percent above 80

km. ” At 120 km and above, it is estimated that the

global water content could be increased by a factor of 100 or more. 4

The production of nitric oxide from the reentry

of HLLVS is expected to increase significantly the

naturalIy occurring NOX concentration and to exhibit a pronounced long-term corridor effect in the

NOX distribution of the mesosphere. 5 Stratospheric

NOx levels would also be altered due to downward

diffusion from the mesosphere, but would be confined mostly to the lower stratosphere where their

impact wouId be negligible.

In the mesosphere, the injection of water could

induce luminous, thin, or “noctilucent” clouds of

ice crystals in the vicinity of the rocket exhaust. It

is estimated that the cloud would expand from a

size of 1 to 1,000 km2 over 24 hours. 16 This finding is

based on theoretical calculations and observations

of other rocket launches that deposited far less

water into the mesosphere than that which is projected for the HLLVS. The clouds are not thought to

‘ ‘ Iblcl

‘‘Iblcl

‘ ‘Program A~ses\ment Report, Statement oi Finding>, Satelllte Power

Systems Concept Development and Evaluation Program, DOE/NASA

Report, DOE/E R-0085, November 1980

“Environmental A$$es$ment for the $ate//tte Power \y$tem – Concept

Development and Eva/ua tlon Program – A tmo~pherlc E ffect$,

DOE/E R-0090, November 1980

‘‘Supra note 9

“Supra note 6

alter significantly the global climate, but in view of

the poor understanding of the coupling between

the mesosphere and troposphere, this expectation

requires further analysis. A large unknown is the effect of the excess water content on temperature

that may affect the likelihood and persistence of

the clouds. 7

In the stratosphere, detectable depletion or

enhancement of the ozone layer from the emission

of water and nitric oxide would be unlikely. While

water vapor tends to decrease ozone, nitric oxide

tends to increase it. The net effect of SPS reference

system effluents is thought too small (i. e., either a

decrease or increase on the order of 0.01 percent)

relative to the natural fluctuations of the ozone

concentration. 8 This conclusion requires further

verification as it is based on one-dimensional

models.

In addition to the formation of noctilucent

clouds and perturbations of the ozone layer, the

water vapor deposited in the stratosphere and

mesosphere might contribute to a chronic partial

depletion of the ionosphere. However, this is expected to be very small in comparison to the local

depletions caused by rocket emissions directly into

that region. ’9 Climatic effects might occur from

changes in the chemical composition of the upper

atmosphere, although at present it is not possible

to assess reliably any potential effects. Research

priorities for SPS upper atmospheric effects incIude

●

●

●

●

●

●

●

update emissions inventory and estimates of

reentry NOX

;

estimate magnitude of corridor effect and

study possible temperature feedback mechanisms;

identify and augment existing experimental

programs to make high-altitude measurements

of water and NOX concentrations, study highaltitude water release data;

assess the possibility and climatic impacts of

noctilucent clouds;

develop scenarios of SPS impacts on a number

of different background conditions including

future increases of C02

;

document and verify effects of effluents that

are now thought to have a minor impact on the

upper atmosphere; and

determine telecommunicate ions effect of

chronic, partial depletion of ionosphere (from

water vapor injected in the stratosphere and

mesosphere).

‘Ibid

“$u prc? note 9

‘5u[)r~ note 6
280 ● Solar Power Satellites

Ionosphere

The ionosphere is used extensively in telecommunication systems to propagate and reflect radio

waves. The injection and diffusion of SPS launch

propellants into the ionosphere could alter the density of the electrons and ions that are responsible

for the unique properties of the ionosphere, thereby degrading the performance of the telecommunications systems. Other effects might also occur,

such as enhanced airglow and increased electron

temperature, but the Iikelihood and consequences

of these impacts are yet to be determined. 20

A reliable assessment of the effects of launch effluents on the D-region of the ionosphere cannot be

made at this time. However, two apparently counteractive effects have been postulated. z

’ The emission of water vapor into the D-region is Iikely to

deplete the ionospheric plasma density. This would

reduce radio wave absorption in the daytime ionosphere and result in propagation anomalies. On the

other hand, NOX

, produced by frictional heating

during reentry, could engender the formation of

ions in the D-region. It is believed that enough NOX

would be deposited in the region to compensate for

the reduction of the plasma due to water vapor. A

recent lower ionosphere experiment suggests that

anomalies in the propagation of VLF signals were

due to the effects of rocket effluents. ” While the

experiment was not conclusive, it is clear that detectable effects might occur that warrant further

study.

As in the D-region, current understanding of the

launch effluent effects on the E-region is not very

advanced. Rocket propellants would be directly injected only into the lower E-region because HLLV

engines would be shut off at 124 km.23 Some effluents would enter the upper E-region by upward

diffusion. Exhaust products emitted above the Eregion in LEO by PLVS, POTVS and HLLV could also

diffuse and settle downwards. The impacts of these

effluents on the E-region, however are very uncertain. It is possible that the deposition of ablation

materials during reentry could augment a radio

signal altering phenomenon called “sporadic E“ in

which regions of greatly enhanced electron concentration are created. In addition, the coupling

between the ionosphere and magnetosphere, the

‘OSupra note 9

“ Ibid

“C Meltz and J A Darold, “VLF OMEGA Observations of the ionospheric Disturbance produced by an Atlas HEAO-C Launch, ” In Proceedings of the Workshop/Symposium on the Prellmlnary Evaluation of

the Ionospheric Disturbances Associated WIIh the HEAO-C Launch, With

Applfcatlons to the SPS Ertvfronmental Assessment, M Mendlllo and B

Baumgardner (eds ), DOE/NASA report Conf 7911108, August 1980

2’Supra note 9

ozone layer, air conductivity, and hence climate

could be affected by the effluents but no reliable

conclusions can be made at this time.

The effects of rocket exhaust products are better

understood in the F-region, but the impact of SPS

effluents is still not certain. This region is

dominated by oxygen atoms that recombine more

slowly with electrons than their molecuIar counterparts in the lower ionosphere. Exhaust products

such as water, hydrogen and C02 emitted in the Fregion become quickly ionized by charge exchange

reactions with the existing atomicions.24 These

molecular ions rapidly recombine with the ionospheric electrons, thereby causing a region of pronounced depletion known as an “ionospheric

hole.” It has been estimated that for each POTV

launch (which would occur once or twice a month),

an ionospheric hole with an area two to three times

the size of the continental United States25 would be

formed and persist for 4 to 16 hours. z

’ Each HLLV

launch (one or two per day) would produce a hole

about one-tenth the size,27 lasting 4 to 12 hours. It

has been suggested that a long-term low-level

depletion on the order of 10 percent would develop

in a ring around the launch latitude as a result of

multiple launches .28 The probable consequence of

this depletion ring is a small perturbation of VLF,

H F, and possibly VHF wave propagation.

These findings were based on a number of theoretical models of the ambient and perturbed Fregion as well as several observations of rocket

effluent-induced ionospheric holes. The models are

fairly well developed and theoretical mechanisms

are well understood, but care should be taken in

scaling up radiowave propagation effects. Further

study is required in order to predict accurately the

location, size, movement, and lifetime of the hole

as well as the cumulative effects of multiple

launches. 29 An observation of ionosphere depletion

inadvertently took place after a 1973 skylab flight

that produced a hole 1,000 km in radius.30 In 1977,

experiments were conducted to purposefulIy produce an ionospheric hole. 31 The experiments,

named Project LAGOPEDO tended to confirm the

“E Bauer, Proceedings of the Workshop on the Mod/ f/cation of the Upper Atmosphere by the Sate///te Power System (SPS) Propu/slon Eff/uents,

DO E/NA$A Report Conf -7906180

“Supra note 14

“Supra note 6

‘

7 Supra note13

‘Ulbld

“Supra note 9

‘“M Mendlllo, C Hawkins, and J Klobuchar, An Ionospheric Tota/

Electron Content Disturbance Associated With the Launch of NASA

$k ylab, Air Force Cambridge Research Laboratories, July 1974

“ Pongratz, et al , Lagoped~Two F-Region Ionospheric Dep/etion Experlment~ Los Alamos Scientlflc Laboratory, LA-U R-77-2743
Appendix D—Environment and Health . 281

theory. Recently, DOE took advantage of the

launch of NASA’s High Energy Astrophysical Observatory (HEAO-C) by an Atlas/Centaur rocket in

order to monitor the resultant large-scale (1 million

to 3 million km2

) effIuent-induced ionospheric hole,

which persisted for approximately 3 hours.32 The

preliminary finding indicates that no severe longterm impacts on HF radio signals occured as a

result, but that VLF transmissions (14 KHz) could

have been affected.33 On the whole, not enough is

known about SPS-induced ionospheric holes to

make conclusions about their impacts on telecommu n i cat ions.

In addition to telecommunication effects, other

potential effects of SPS rocket effluents deposited

in the F-region have been suggested .34 Enhanced

airglow emissions could affect astronomy, remote

sensing, and surveillance systems. Past observations have noted enhancements on the order of 10

kilorayleighs for certain visible and near infrared

emissions. 35 The magnitude and significance of SPS

airglow emissions warrants further study. The injection of water vapor in the F-region might also perturb the thermal budget of that region. This would

increase the ratio of cooling by radiation and

perhaps alter the Van Allen belts and the amount

of ionizing radiation in space. Also, as noted

previously, the number of hydrogen atoms emitted

by HLLV launches in the upper thermosphere and

exosphere could be comparable to the number

naturally present. This could increase satellite

drag, alter the Van Allen belts, and affect radio

communications. The water budget of these

regions is not well understood however, and so the

probability of these effects is not known.

Research should focus on the following areas:

●

●

●

●

improve understanding of D&E region effects;

refine studies of F-region ionospheric holes in

order to predict location, size, movement, and

lifetime;

test effects on telecommunications systems

using D, E, and F regions; and

assess airglow effects perhaps with the involvement of the remote sensing and astronomy communities. 36

“M Mendlllo and B Baumgardner, Proceedings of the Workshop/Sumposlum on the Preliminary Eva/uatlon of the Ionospheric Disturbances

Associated W/th the HEAO-C Launch, W/th Appl{catlons to the SPS Env/-

ronmenta/ Assessment, DOE/NASA Report Conf 7911108, August 1980

“Ibid

“Supra note 9

‘

5 Supra note13

‘blbld

Thermosphere and Exosphere

As discussed above in the Stratosphere and Mesosphere summary, HLLV flights are predicted to

substantially increase the natural water content

above 80 km. One consequence of this excess

could be an increase and, perhaps, doubling of the

upward flux of hydrogen atoms that result from the

breakdown of the molecular water vapor as well as

molecular hydrogen emitted above 56 km by

HLLVS, PLVS and POTVS.

37 While it is fairly certain

that an increase in the hydrogen flux would result,

the consequences of a perturbed hydrogen cycle

are quite uncertain. The hydrogen escape rate into

outer space could increase. Accumulation of

hydrogen above 800 km might also occur, thereby

possibly altering thermospheric and exospheric

dynamics and enhancing satellite drag.

Research is needed to:

. improve understanding of the natural hydrogen cycle and dynamic processes of the thermosphere and exosphere; and

● design models to quantify hydrogen increases

and simulate SPS effects on a global scale.

Plasmasphere and Magnetosphere

SPS reference system effects on the plasmasphere and magnetosphere result primarily from

the emission of COTV argon ions and POTV hydrogen atoms as the vehicles move between LEO and

GEO. 38 The impacts of these effluents could be

great, because the energies and number of ions and

atoms injected would be substantial relative to the

ambient values. Unfortunately, the magnetosphere

and plasmasphere are poorly understood. While

some potential SPS impacts have been identified as

shown in table D-4, their probability and severity

cannot be assessed since no experimental data relevant to SPS exists for these regions. I n particular,

the consequences and the mechanism of interaction between the argon ions and the ambient

plasma and geomagnetic field must be explored.

In addition to the exhaust products, the satellites

themselves could also have an impact on the magnetosphere by obstructing plasma flow, or producing dust clouds, electromagnetic disturbances,

space debris, visible and infrared radiation, and

high-energy electrons.39 Little emphasis has been

placed on these potential effects, however,

because they are thought to be minor and easily

reinedied.

“Supra note 6

‘“Supra note 9

“lbld
282 ● Solar Power Satellites

Table D-4.—Satellite Power System Magnetospheric Effects

Effect Cause Mechanism System/activities impacted

1. Dosage enhancement of O + and Ar + in magneto- Thermal heavy ions suppress

trapped relativistic sphere due to exhaust and ring-current-ion cyclotron

electrons plasmasphere heating turbulence, which keeps

electron dosage in balance

in natural state

2. Artificial ionospheric Ionospheric electric field Beam induced Alfven shocks

current induced by argon beam propagate into ionosphere

3. Modified auroral response Neutrals and heavy

to solar activity large quantities

4. Artificial airglow 3.5 keV argon ions

5. Plasma density disturbance Plasma injection

on small spatial scale

ions in Rapid charge-exchange loss

of ring-current particles

Direct impact on atmosphere

from LEO source

Plasma instabilities

—Space equipment

—Modification of human

space activity

—Powerline tripping

—Pipeline corrosion (probably

unimportant)

—May reduce magnetic storm

interference with Earth and

space-based systems

—Interference with optical

Earth sensors

—Signal scintillation for

space-based communications

SOURCE: Environmental Assessment for the Satellite Power System, Concept Development and Evaluation ProgrammAtrnosptreric Effects, DOEIER-0090,

November 1980.

If an SPS program is conducted, it is clear that

the design of transport vehicles for the outer regions of the atmosphere and the environmental assessment of their impacts in these regions will be

closely linked. Possible methods of reducing adverse effects include the use of both chemical and

argon ion engines or an alternative propulsion system in the COTV, and lunar mining.

Near term studies include:

• design and implement experiments in the

magnetosphere and the laboratory to test SPS

effects and increase theoretical understanding

of magnetospheric phenomena.

The Electromagnetic Characteristics of

the Alternative SPS SatelIites

Microwave Satellites

The satellite would generate microwave power

at a frequency of 2.45 GHz or some other central

radio frequency, thermal radiation, and reflected

sunlight at all solar wavelengths. In addition, it

would generate some power at multiples of the

central frequency (harmonics), and also spurious

noise on either side of the central frequency.

Because the reference system is the only system for

which an attempt has been made to characterize a

system completely, this report will use its

characteristics as an illustrative model for all

microwave systems.

The space antenna would radiate a total of 6,720

MW of microwave power towards Earth. The reference system design calls for the power distribution

over the face of the satelIite antenna to be gaussian

with a 10-d B taper. The resuIting beam pattern is

shown in figure 40, p. 211. Atmospheric scattering

and attenuation due to absorption, in addition to

losses at the rectenna would reduce the usable

power at the rectenna to 5,000 MW. The following

radiative effects are the most important for the

reference system (fig. D-2):

● Out-of-band radio frequency emissions. The

reference system’s klystrons are estimated to

radiate energy at the following harmonic frequencies: 40

Power level

Frequency (C HZ) (times 6,720 MW)

245- (central frequency) 1

490- (second harmonic) -50d B(10-5

)

7 35- (third harmonic) -90d B(10-9

)

980- (fourth harmonic) -lOOd B(10 1O)

Although it is known that the antenna patterns for these frequencies would be rather different from that of the reference system, current antenna theory is inadequate to predict a

detailed spatial pattern.

Spurious sideband noise generation from

the klystrons outside of the central frequency

is estimated to be no greater than – 200 d B of

the central frequency at a separation of 8 to 10

MHz from the center frequency. Filtering may

be able to reduce this to levels which would

not cause appreciable interference in most

cases This is one constraint in the separation

necessary between an SPS frequency assignment and the boundaries of the 2.45 GHz International Scientific and Medical band. These

considerations apply after the klystron tubes

have warmed up. Since, on the average the

4 

——

‘C, L) \rndt and L Leopold, “Environmental Conslderatlons for the

MI( rowav(, [learn from a Solar Power Satel I lte, ” I )th /nter\oclety Energy

( of)kerslrv) I nglneer~ng ( orrferrwce, San Diego, Callf , August 1978
Appendix D—Environment and Health ● 283

Figure D-2.–Overview of Potential SPS Electromagnetic=Compatibiiity impacts

noise & harmonics

SOURCE: Power (SPS), Concept Development and Evaluation Program p. 43,

100,000 klystrons in the antenna can be expected to fail at a rate of five per day, out of

band radiation as they fail and as they warm

up after being replaced may be greater than

during their operating period.

The reflected beam at 2.45 GHz, at the harmonics, as welI as at other frequencies generated by the rectenna structure itself, would

result in a complicated power spectrum which

wouId change in time as the rectenna ages.

The radiation patterns are expected to be 100

or broader and partially directive. A capability

to monitor and locate rectenna intermodulation emissions is required to allow timely

structural repair to assure no interference with

sensitive terrestrial and aircraft equipment.

Optical and thermal emissions. The reference

satellites would reflect sunlight in three major

ways41 42 1) diffuse reflections from the solar

arrays, the antenna and the underlying structure; 2) specular mirror-like reflections from

the solar arrays and the antenna; 3) glints or

specular reflections from the underlying structure. Diffuse reflections would cause each

satellite to appear as bright as the planet

Venus at its brightest phase (magnitude – 4.3).

Specular reflections would occur near the

equinoxes just at local sunrise or sunset (i. e.,

on the same meridian as the satelIite) and

wouId cause a 330-km wide spot of Iight several times brighter than the full Moon to sweep

4

‘ P A E and M Stokes (eds ), “Workshop on Power

 Effects on Optical and Radio Astronomy, ” CON F-7905143

(DOE ], 

 I “Apparent 1 of Solar Power Satellites, ”

 Power 1980, pp 175190
284 ● Solar Power Satellites

across the affected area in a few minutes.

Glints from components of the satellite’s

structure are not expected to be as serious as

the diffuse or specular reflections and in any

event, may be significantly reduced or eliminated by proper structural design.

In addition to reflecting sunlight, the satellite would also emit thermal radiation of an

estimated intensity of 6.3 X 10 6 watts p e r

square meter at the Earth. The precise wavelength peak depends on the details of the characteristics of the satellite’s components (e.g.,

type of cell, type of antireflection coating,

etc. ) but would Iikely fall in the 5 to 10 micron

band. The thermal radiation is expected to exceed SIightly current interference levels.

Laser Satellites

As with the other characteristics of laser systems,

the electromagnetic characteristics of the laser

satellite are ill defined. However, the following

general radiation effects can be expected. Quantitative data will be available only after th e

systems become more highly defined.

In general, laser systems would reflect sunlight

from the laser platform and from the relay mirrors

in LEO and CEO, if any. I n addition, they wouId

radiate thermal energy, most probably in the 5 to

10 micron region of the infrared. They would also

be detectable as a thermal source of microwave

power.

● Reflected sunlight. The brightness of Iaser satellites at CEO or LEO would depend on the

mode of power CoIIection and conversion (e. g.,

photovoltaic or direct solar pumped) and the

overalI size of the satellite. OpticalIy, the most

important differences are that the LEO satellite would be brighter and perceived as moving slowly by terrestrial observers.

Because they would be smaller than the reference system satellites, individually they

would also be less bright. However, there will

be more of them. (If laser satellites could be

made to operate with the same efficiency as

the microwave designs, five 1,000-MW or ten

500-MW satellites would be needed to equal

reference system capacity. ) Laser relay mirrors

in LEO and GEO would contribute both stationary and moving sources of light. However,

because of their small size (several meters),

they are not expected to be readily visible

from Earth.

● Hea t radiation. Because an appreciable

amount of the sunlight which is intercepted by

the laser satellite would be absorbed and reemitted as heat, the satellite, whether in CEO

or LEO, would be a diffuse infrared radiator

and would radiate some energy at microwave

frequencies as well.

• Laser beam characteristics. The two major present laser alternatives operate near 5 microns

(CO laser) or 10 microns (CO2 laser) infrared

wavelengths. Because the beams are highly

directive, they would be only slightly observable in the infrared except for receivers placed

very near the laser ground stations. Scattered

light from the beam would be detectable in

the lower part of the atmosphere.

Mirror Satellites

Because the mirrors are designed to reflect

sun Iight only, their emissions wouId be only sIightly

altered from the original solar spectrum (i. e., they

wouIdn’t radiate appreciable infrared or microwave radiation). Those emissions would be large,

however, for the ground base into which the sunlight is directly reflected (i.e., the equivalent of one

Sun).

● Terrestrial observers away from the ground

site would see moving patches of light about

0.5 min arc across surrounded by an aureole of

scattered Iight. The precise apparent brightness of the mirrors wilI depend on a number of

factors, e.g., the orientation of the mirror with

respect to the observer, the relative position of

the Sun from both the mirror and the observer,

the albedo of the reverse side of the mirrors,

and the atmospheric conditions above the

ground station. Low-intensity scattered sunlight from aerosols and dust high in the atmosphere would be observable at up to 150

km from the ground station.

The Interaction Between Biological

Systems and Electromagnetic Waves

Microwave radiation is a form of electromagnetic energy which is used in numerous commercial, industrial, military, and medical devices including microwave ovens, radar, diathermy equipment, and sealing instruments. The microwave

band accounts for frequencies ranging from 300

MHz to 300 GHz,
Appendix D—Environment and Health ● 285

The extent and consequence of exposure of

biological systems to microwaves depends on the

following characteristics of the incident energy,

the biological organism, and surrounding environment:43

● Frequency of electromagnetic radiation. — T h e

frequency of radiation is the number of complete oscillations per second of an electromagnetic wave. The energy of the radiation is

directly proportional to the frequency. Although the frequency of microwaves is high, it

is not high enough for the quanta to ionize,

i.e., to eject an electron from a molecule or

atom; hence microwaves are called “nonionizing. ” The bioeffects of X-rays and other ionizing radiation are known to be more severe

than those resulting from the nonionizing portion of the spectrum.

The frequency also determines the depth of

penetration when an electromagnetic wave is

incident on biological material. I n general, the

lower the frequency, the greater the depth of

penetration. For example, infrared waves penetrate no deeper than human skin, whereas microwaves (which are lower in frequency) penetrate through the skin and fat and into human

muscle. 44 The relationship between frequency

or wavelength (frequency is inversely proportional to wavelength) and the size of the irradiated body is also important. Resonance (i. e.,

most efficient absorption) will occur when the

length of an organism measures approximately

half of a wavelength of the incident electromagnetic field. For example, the resonance

frequency at which the absorption rate is maximized for the male human body is on the

order of 70 to 100 MHz, whereas the maximum

absorption rate for rats occurs at 2.45 GHz.45

Thus, an electromagnetic wave may elicit a

very different response from organisms of two

different sizes (assuming that the amount of

energy absorbed is the dominant determinant

of a biological response).

Understanding of the functional dependence of bioeffects on frequency is not com-

‘ ‘For a more detailed discussion of the biophysics of microwave interactions with blologtcal systems, see S Baranskl and P Czelskl, i310/oglca/

Effects of Microwaves, Dowden, Hutchlnson and Ross, Inc , Pennsylvania,

1976

“R D Phllllps, et al , Comp//atlon and A$$e$\ment of Microwave BIoeffects A Se/ect/ve Rev/ew of tfre L Iterature on the Blo/og)ca/ L ffectj of

Microwaves In Re/at/on to tfre $ate///te Power $y~tem ($P\), final report,

DOE/NASA, May 1978

“E Berman, “A Review of SPS-Related Microwaves on Reproduction

and Teratology”, I n The Flna / Proceedings of the $o/ar Power Sate///te Program Rev/ew, Apr 22-25, 1980, DOE/NASA report Conf -800491, July

1980

●

●

●

●

plete. The existence of frequency windows,

i.e., effects observed over one specific range

of frequencies is not well-understood.

Intensity of incident wave. –The energy carried by an electromagnetic wave per unit area

and time is called its power density and is

measured in units of milIiwatts per square centimeter (mW/cm2

). Heating or thermal effects

are generally thought to occur at power densities greater than 10 mW/cm2

. Effects at much

lower power densities have been postulated

but the existence and consequence of “nonthermal” phenomena remains in dispute. Power density windows have been observed experimentally in which bioeffects are noted

only over a specific range of power densities

and not above or below.

Recently, the microwave community has

adopted the specific absorption rate (SAR) as a

measure of the energy absorbed by a biological organism. The SAR is expressed in units of

milliwatts per gram (mW/gm). It is a function

of the power density and weight of the irradiated organism. While the SAR provides

more information about the bioeffects of

microwaves than it does of the power density

alone, it cannot be used to entirely predict the

effects of exposure to microwaves. The SAR is

averaged over the entire body; it does not consider energy absorbed differentially in specific

body parts. It also does not account for possible nonthermal effects. Furthermore, it does

not measure the “biological effectiveness” of

a microwave, i.e., its ability to induce an effect

which is dependent on parameters such as the

relation between the frequency and size of

subject or body part.

Duration of exposure. – For thermal effects,

the length of exposure may influence the

body’s ability to cool. Heating resulting from

long duration exposure of high-intensity waves

may overwhelm the natural cooling system. At

lower power densities, i.e., “nonthermal”

levels, the cumulative or long-term effects are

not known.

Waveform. – It is thought that the biological

consequences of exposure to continuous wave

radiation is usually less severe than from that

which is pulsed or modulated, although basic

appreciation of the mechanisms of interaction

is lacking,

Subject characteristics. – Bioeffects are species-specific, primarily because the factors

which determine energy absorption such as

size, structure, body, insulation, and heat dis83-316 0 - 81 - 20
286 ● Solar Power Satellites

●

sipation, and adaptive mechanisms vary with

species. The composition and geometry of biological matter also determine the depth of

penetration and wave characteristics; tissue,

muscle, and fat each exhibit different dielectric and conductive properties. Thus, without

adequate theories of interaction, extrapolations from animal studies to human bioeffects

are extremely difficult. The sex, age, and state

of health of an irradiated subject may also be

an important factor, since size and susceptibility to certain kinds of effects may differ

with respect to these parameters. It also appears that electromagnetic radiation may act

synergistically with drugs. The differential absorption of energy may result in hotspots. This

relatively increased energy deposition in cells,

organs or parts of the body relative to its surroundings could lead to very specific biological effects after exposure.

The orientation of the organism with respect

to the electric field component of the wave is

also important —the most energy is absorbed

when the electric field is parallel to the long

axis of the body. In animal experiments, physical restraints or sedation might influence

study results. Measurement devices such as

implanted probes could also alter the field

distribution. The prediction of bioeffects may

also be complicated by movement of the subject in the field which changes the absorbed

energy dosage and may result in modulation

of the field.

The effects of whole body irradiation may

differ from partial body exposure. In addition,

for either whole or partial body irradiation,

smaller body parts could resonate if the frequency used was in resonance with that part

of the body.

Environment. –The humidity, temperature,

and air circulation of the surrounding environment will affect the ability of a heated biological entity to cool. Objects near the electromagnetic field could also enhance, reflect,

absorb or distort it. For SPS, the effects of the

space environment on the biological response

to microwaves are not known.

SPS-Related Microwave Bioeffects

Experiments (conducted by DOE, EPA)

In conjunction with the SPS DOE assessment,

three studies were initiated and managed by EPA.46

• Exposure of bees to 2.45 GHz at 3, 6, 9, 25 and

●

●

50-mW/cm2. No statistically significant effects

on behavior, development, or navigation have

been observed following short-term exposure.

Long-term exposures are planned and should

clarify this possible effect. It has also been

proposed that tests of effects on bee navigation be carried out in the absence of sunlight

(which may possibly mask microwave induced

effects).

Immunology and hematology studies of small

mammals exposed for short durations to about

20 mW/cm2

, 2.45 GHz microwaves. No effects

have been reported so far.

Experiments testing the effects on the behavioral and navigational capability of birds subjected to acute and chronic exposures of 2.45

GHz fields. Some mortality has resulted from

exposure to 130 to 160 mW/cm2 microwaves

and has suggested that species and body geometry determine tolerance levels. Generally,

no statistically significant effects have been

detected at power densities of 0.1 to 2 5

mW/cm2

. Some birds chronically exposed to

25 mW/cm2 have exhibited an increase of aggressive behavior, although the number of

birds is statistically insignificant.

Laser Bioeffects

Lasers are unique among light sources because

of their capacity to deliver an enormous amount of

energy to a very small area at a great distance.47

The primary biological consequence of this property is heating. However, nonthermal mechanisms

‘“C H Dodge, Rapporteur, Workshop on Mechanisms Underlying Effects of Long-Term, Low-Level, 2450 MHz Radlatlon on People, organized

by the National Research Council Committee on Satelllte Power Systems,

Environmental Studies Board, National Academy of Sciences, ] uly 15-17,

1980

4 ‘E- Kle IrI ‘ Hazards of the Laser,” Hosplta/ Practice, May 1967, pp

48-5 J
Appendix D—Environment and Health ● 287

have also been suggested.48 For example, photochemical reactions are thought to be responsible

for damage of biological organisms exposed to

ultraviolet lasers.49 High laser power densities may

also cause injury from shockwaves or high electric

field gradients.50 Biological electromagnetic interference effects have also been proposed. 51

Clearly, the mechanisms of interaction between

laser light and biological entities are not completely understood. Like microwaves, little is known

about the cumulative or delayed effects of chronic

exposure to low levels of laser light.52 In general,

the higher the power and the shorter the period, the

greater the damage.53 The extent of the effect also

depends markedly on the characteristics of the irradiated biological material. Of primary importance is a tissue’s absorptivity, reflectivity, water

content, and thermal conductivity.

The organ of the body most sensitive to laser

radiation is the eye. The ocular media of the human

eye transmit light with wavelengths between 400

and 1,400 nm. 54 There are two transmission peaks in

the near infrared at 1,100 and 1,300 nm. Light in the

visible and near infrared spectrum is focused

towards the retina. The refraction of the laser beam

by the ocular media amplifies the light intensity by

several orders of magnitude.55 As a result, in this

spectral region the retina can be damaged at radiation levels which are far less than those which produce corneal or skin damage.

For lasers that emit wavelengths outside of the

visible and near infrared range, the ocular effects

are quite different. At ultraviolet wavelengths, for

example, light is absorbed primarily by the cornea,

which can be injured by photochemical reactions.

Infrared radiation is not focused on the retina

‘“V T Tomberg, “Non-Thermal Blologlcal Effects of Laser Beams, ”

Nature, VOI 204, Nov 28, 1964, pp 868-870

“Department of the Alr Force, Ffea/th ~azdrd~ Contro/ for Laser Radlatlon, AFOSH Standard 161-10, May 30, 1980

‘[)lbld

‘‘M Zaret, “Laser Appl Icatlon In the F Ield of Medlclne, ” ZAMP, VOI 16,

1965, pp 178-79

“M L Wolbarsht and D H Sllney, ‘Needed More Data on Eye

Damage, ” Laser Focus, December 1974, pp 11-13

‘‘Supra note 47

“W T Ham, et al , “The Eye Problem In Laser Safety, ” Arch Env/ronmenta/ Hea/th, VOI 20, February 1970, pp 1 ;6-160

“D H Sllney and B C Fresler, “Evaluation of Optical Radlatlon

Hazards, ” App/ied Opt/es, VOI 12, No 1, j anuar~ 1973, pp 1-24

either, but is absorbed by the cornea and lens. Most

of the radiation from the C02 laser is absorbed in

the 7 nm tear layer of the cornea. 56 Continuous irradiances of the order of 10 W/cm2 could produce lesions within the blink refIex.57 Corneal damage may

be reversible or repairable but severe damage may

result in permanent scarring, blurred vision, and

opacities. 58 The lens is particularly susceptible to

injury because of its inability to eliminate damaged

celIs. Lenticular damage characterized by cataracts or clouding may occur at irradiance levels

that do not produce corneal injury. For example,

“glassblowers cataracts” are thought to result from

chronic exposure to 0.08 to 0.4 W/cm2 infrared

radiation. 59 Proposed thermal limits for pulsed C02

lasers range from 0.2 to 1.0 W/cm2, ’0 but this

recommendation requires further study.

Effects on the skin from absorbed radiation may

vary from mild erythema (sunburn) to blistering

and/or charring. 61 The principal mechanisms of injury by infrared radiation are thermal and are a

function of tissue reflectance, spectral depth of

penetration, and the size of irradiated area. Since

thermal burns are produced at temperatures higher

than that which causes pain, in most present occupational situations the pain can serve as warning.

A definite sensation of warmth is produced from

C 02 lasers at 0.2 W/cm2 over an irradiated area

only 1-cm diameter, or 0.01 W/cm2 for full body exposure. 62 Heat stress should not be overlooked.

More research is needed to determine the effects

of chronic or repeated exposures.

As was the case for exposure to microwaves, the

determination of laser thresholds and standards is

exacerbated by problems of detection and measurement, instrument sensitivity, dosimetry, interspecies and interfrequency extrapolation, and lack

of complete knowledge of physiological systems,

mechanisms of interaction, and synergistic effects.

‘“U \ Army Environmental Hyglence Agency, Laser and Opt/ca/

Haiard~ Course Manua/, Aberdeen Proving Ground, Md , 8th ed , ]anuary

1979

‘‘D H Sllney, K W Vorpahl, and D C Wlnburn, “Environmenta l

Health Hazards From High-Powered Infrared Laser Devices, ” Arch Env/ronmenta/ Hea/tfr, VOI 30, April 1975, pp 174-179

‘“ Supra note 47

‘

9 Supra note 55

““Suprd note 49

“ Ibid

‘

2 Supra note 55
288 ● Solar Power Satellites

Experiments also make clear that the extent of the

superficial or immediate lesion is no gage of total

damage. ’3

The exposure limit for continuous wave infrared

lasers as recommended by ANSI is 100 mW/cm2 for

exposures over 10 seconds and for smalI spot sizes

on the skin or eyes.64 A whole body irradiance limit

of 10 mW/cm2 has been suggested .65 It should be

stressed that the protection standards for repetitive

and chronic exposures and for wavelengths outside

the visible band are based on a considerable

amount of extrapolation. Data obtained from nonIaser sources, such as bright, small-source lamps

and high luminance extended sources cannot accurately and wholly represent the effects of laser

radiation in determining injury thresholds for

ultraviolet and infrared lasers directly.

General Health and Safety of

SPS Space Workers*

The human body’s tolerance to acceleration

depends on the duration and magnitude of the

acceleration, the positioning of the body relative to

the accelerating force, the restraint and support

systems of the spacecraft and the time spent in a

weightless state. ” Research is needed to quantify

effects as a function of these parameters and to

determine the tradeoffs between short duration,

high acceleration and longer duration, lower acceleration effects. Studies should also evaluate the

tolerance in the population that may fly in space

(since variation in individual response levels are

great) and explore possible ways to reduce harmful

effects. ”

Weightlessness is known to induce a number of

physiological responses such as decreased heart

rate, shifting of fluids to the upper body, decrease

of muscle mass and loss of bone minerals .68 Most

of the observed effects have been temporary; only

bone calcium loss appears to require a long period

b

* Supra note 47

‘“American Natlona/ Standard for the Safe Use of Lasers, ANSI (R)

Z136 1-1979, American National Standard Institute

“D H S1 Iney and D L Cono\,er, “Nonlonlzlng Radlatlon” In /rrdustr/a/

Errv/ronmenta/ Hea//h, L V Cralley and P R Atkins (eds ) (New York

Academic Press, 1975), pp 157-172

*See text for discussion of Ionlzlng radlatlon effects

6bEnvironmen/a/ Assessment for the Sate///te Power ‘5 y$tern Concept L)eve/opment and Eva/uatJon Program, DOE/E R-0069, August 1980

“lbld

“Program Assessment Report, Statement of F/nd/ng~, Satelllte Power

System Concept Development and Evaluation Program, DOE/E R-0085,

November 1980

of recovery following return from space.69 For SPS,

however, the effects of periodic weightlessness

over a long time period need to be investigated.

Moreover, ameliorative measures suitable for a

large number of people with broad physiological

characteristics must be investigated .’”

Workers would be exposed to electric fields

generated by the collection and transmission of

large amounts of electricity across the solar panel

and antenna, but effects of electric and magnetic

fields on biological systems are not well-understood.71 Research is needed to determine the bioeffects of magnetic fields generated by satellite

electric currents, as well as to assess the effects of

field absence over extended stays in orbit, as CEO

is largely outside of the Earth’s magnetic field.

Some space workers could also be exposed to high

levels of microwaves. The effects of microwaves in

a space environment deserves special attention. It

is known, for example, that microwaves can work

synergistically with ionizing radiation to increase

the biological effectiveness of the latter. ”

Research would be required to determine bioeffects and if possible, to develop suitable

exposure Iimits and protective clothing.

Psychological impacts must also be assessed,

especially since there is little information on large,

mixed gender groups working in close confinement

for prolonged periods. Studies should also consider

the effects on workers’ families and friends and

possible mitigation measures such as careful worker selection, recreation faciIities, social management, etc.

Space workers could be prone to greater safety

risks than their terrestrial counterparts because of

the possible awkwardness of working without gravity.73 Risks also stem from the high-voltage equipment and handling of toxic materials. There is a

danger that spacecraft charging could produce

electric shocks great enough to injure or kill

workers, although this might be avoided by a judicious choice of spacecraft material. Catastrophic

CoIIisions with meteoroids or space debris are also

possible, given SPS’s large size. Extravehicular

activity may also create hazards.

—

‘

}

’lbld

‘(’lbld

7‘ Jupra note 66

‘ Baranskl and P Czerskl, L310/oglca/ Effects of M/crowave~, Dowden,

Hut, hlnson and Ross, Pennsylvania, 1976

7 ‘\upra note 66
Appendix E

EXAMPLES OF INTERNATIONAL COOPERATION

Part 1

Intelsat was preceded by the formation of a

domestic company, Comsat. In 1962 the Federal

Government, after extensive debate over the proper degree of Federal involvement, chartered Comsat Corp. to provide a commercial communications

satellite system “in conjunction and cooperation

with other countries . . which wilI serve the communication needs of the United States and other

countries, and which wilI contribute to world peace

and understanding.’” Comsat was not directly

owned or run by the Government; it issued shares

of voting public stock (which were immediately

over-subscribed), with 50 percent of these reserved

for “common carriers” —AT&T, ITT, Western

Union, and others. The Board of Directors consisted of three Presidential appointees, six common

carrier representatives, and six elected at large.

However, although Comsat was not directly financed by the Government, it received and continued to receive the benefit of extensive NASAsponsored development of communication satellites and launch-vehicles, free of charge–some

several billion dollars worth. (NASA research on

communications satellites was cut back under the

Nixon administration but reemphasized in the

Carter administration’s October 1978 White House

Fact Sheet, largely as a result of increased competition from Japan and Western Europe.)

Under its charter, Comsat was allowed to enter

directly into negotiations with foreign entities with

the supervision and assistance of the State Department. In 1963, a U.S. negotiating team proposed a

framework for an international telecommunications satellite organization: lntelsat. In a series of

meetings details were agreed on: 1) that Comsat

wouId be the consortium manager2 and majority

owner, with an initial 61 percent of the shares; 2)

that ownership and utilization charges, as well as

voting, would be in proportion to the use of the

system by each participant, readjusted on an annual basis, and that membership would be open to

alI ITU member nations, with a minimum 15-percent share needed for representation and voting; 3)

there would be two levels of agreement, one direct-

“’Communlcatlon> Satellite Act of 19b2, In Space Law, Se/ected Ela$fc

Documents, Senate Committee on (’ommerce, Science, and Transport

tlon, Dec 1978, p 523

‘Joseph N Pelton, G/oba/ Comrnunlcatlons Sate//(te Po/Icy lnte/sat,

Po/ItIcs and funct~onallsm (Mt Airy, Md Lomond Books, 1974), p 76

(p 55)

Iy by nations, the other by designated agencies

(“signatories”), one per nation; 4) that Intelsat

would be restricted to providing services between

countries, not within countries; 5) the interim

agreements would last 5 years, at which point permanent arrangements wouId be agreed on.

One immediate result was the refusal of the

Soviet Union and East Europe to participate. The

Soviets used only a miniscule amount of global

communications traffic, some 1 percent, and

would not join an organization dominated by the

United States and West Europe. They began developing their own domestic system (Molniya), which

later formed the core of their international system,

Intersputnik, covering the Soviet Union, East

Europe, Cuba, and Mongolia.

When the interim agreements were renegotiated,

from 1969 to 1971, the basic structure was retained.

However, a number of changes were made, many

of them designed to reduce U.S. dominance and to

increase the direct role of national governments.3

Comsat was phased-out as the manager, management being turned over to a Director General,

responsible to a Board of Governors composed (in

1979) of the 27 largest participants or groups of participants, representing a total of 83 signatories. A

new voting structure was established to prevent de

facto U.S. veto power. The minimum participation

was lowered to 0.05 percent. AlI signatories and

states parties were entitled to receive free, technical information generated by Intel sat contracts.

Intel sat was allowed to provide services to domestic and regional satellite groups. Net property in

1980 is valued at $663 mill ion, with $523 million of

that in the space segment proper. Return on investment in 1979 was better than 14 percent.4

Part 2

Like Intelsat, Inmarsat is a commercial, profitmaking venture with a corporate structure and independent legal personality. Comsat is the U.S. signatory, holding the largest original share at 17 percent; Great Britain is second with 12 percent, the

Soviet Union third with 11 percent. ’ Initial capitalization was set at $200 milIion.

Because it could participate on a more equitable

basis, the Soviet Union joined Inmarsat; one conse-

!R IC hard Col lno, The /rite/sat De flnlt/ve Arrangements (Geneva European Broadcasting Union, 1973), p 11-12

‘Intel}at Annual Report 1980 Intelsat, Washington, D C , p 21

“ Operating Agreement on Inmarsat,” 1976, In Space Law, p 445

289
290 Ž Solar power Satellites

quence was Soviet insistence that nongovernmental signatories —e.g., Comsat and Japan’s Kokusai

Denshin, Ltd.—be guaranteed by their governments. It has been pointed out that the Soviet

Union “is disinclined to enter mixed organizations

involving states and private enterprise, ” preferring

to deal only with other states. G

Part 3

The vast majority of Intelsat signatories were

government communications agencies. Only in a

few instances, such as Comsat for the United

States, and Interspazio for Italy, were the signatories separate corporate entities designed for communication satellite operations. One result was a

conflict of interest within agencies that were involved in other communication systems, especialIy

underwater cables. Differences of opinion also developed between Comsat, which wanted to expand

Intel sat into as many other areas, including domestic communications, as possible; and agencies that

wanted Intelsat’s scope restricted to international

telephone and television relay.

At the beginning, Comsat, with headquarters in

Washington, D. C., was the managing agency; American launchers were used through NASA; and the

satellites themselves were built by U.S. firms —

(Hughes for Intelsat I, II, IV, and IV-A; TRW for lntelsat III; Ford Aerospace for Intel sat V). The initial

agreement was structured in such a way that U.S.

participation could never be less than 50.6 percent. 7

Initially, participation by lesser developed counin numbers, tensions developed between LDCs,

Europeans, and the United States over the distribution of benefits. One issue concerned the relative

investment between satelIites and ground stations.

Since users were responsible for building their own

Earth stations, LDCs and others with fewer resources and lower usage urged Intelsat to increase

the size and complexity of the satellite component

in order to reduce Earth-station costs.

As European aerospace capabilities matured,

members began to lobby for larger shares of Intelsat R&D and procurement contracts. Even when

‘Stephen Doyle, “lnmarsat Origins and Structure, ” 1976

‘Pelton, op cit , p 58

European bids were higher than U.S. ones, it was

argued that these were necessary to develop competition for the United States, and that it was unfair

for U.S. firms to reap all the financial benefits.

Over time, U.S. firms began to subcontract extensively abroad in an effort to reduce criticism of U.S.

contract dominance.

In the permanent agreement, procurement policy was established with emphasis on the “best

combination of quality, price and most favorable

delivery time.” However, in the event of equivalent

bids “the contract shall be awarded so as to stimulate in the interests of Intelsat, worldwide competition” (art. 13).8 This loophole gave Intelsat the

option of allocating contracts on a geographic

basis as long as it determined that they were

roughly equivalent. In recent years, approximately

15 percent of the dollar value of Intel sat procurement contracts has been spent outside the United

States 9

Part 4

Unlike ESRO, which had its own facilities, ELDO

was entirely a coordinating body for separate national efforts. The initial planning called for a

British first stage, a French second stage, a German

third stage, and so on. Launches were to take place

in Woomera, Australia. The major countries had

widely differing interests. France was interested in

an across-the-board capability to compete with the

superpowers and demonstrate French independence and prestige, an aim directly connected with

French military programs in nuclear submarines

and intermediate range ballistic missiles. France

feared that the United States would not provide

launch services for French military satellites or for

programs that promised to compete commercially

with the United States.

Germany was more interested in private commercial ventures, and was much more willing to

cooperate with the United States. Great Britain,

faced by the mid-1960’s with severe financial constraints and enjoying a close relationship with the

United States, preferred less expensive programs in

telecommunications and remote sensing.

““ Intel sat Organ lzatlon Agreement, ” 1973, In Space Law, p 214

“Conversation with ]ohn Donahue, Intelsat procurement office, Octobel 1980
ACRONYMS, ABBREVIATIONS,

AND GLOSSARY
Acronyms and Abbreviations

AF – audio frequency

AlAA – American Institute of Aeronautics and

Astronautics

ANSI — American National Standards Institute

A-sat — antisatellite

Aramco – Arabian-American Oil Co.

BBB — blood brain barrier

BRH – Bureau of Radiological Health

Btu — British thermal unit

bui – brain uptake index

CB — citizens’ band

CEP – Citizen’s Energy Project

— centimeter

CMEA — Council of Mutual Economic

Assistance (Comecon) (East Europe,

Soviet Union, Cuba)

CNS – central nervous system

CONAES – Committee on Nuclear and

Alternative Energy Sources (National

Academy of Sciences)

COPUOS – Committee on Peaceful Uses of Outer

Space (United Nations)

COTV — cargo orbital transfer vehicle

Comsat – Communications Satellite Corp.

cpm

CW

dB

dc

DOD

DOE

DMSO

EDL

EEG

EKG

ELDO

ELF

EMF

EMP

EMR

EOTV

EPA

ER

ESA

ESRO

FCC

FDA

FEL

CDL

GNP

GHz

Gw

— counts per minute

— continuous wave

– decibels

– direct current

— Department of Defense

– Department of Energy

– dimethyl sulfoxide

— electric discharge laser

— electroencephalogram m

— electrocardiogram

– European Space Vehicle Launcher

Development Organization

— extremely low frequency

— electromagnetic fields

— electromagnetic pulse

— electromagnetic radiation

— electric orbital transfer vehicle

— Environmental Protection Agency

— evoked response

– European Space Agency

– European Space Research

Organization

— Federal Communications Commission

— Food and Drug Administration

— free electron laser

— gas discharge laser

– Gross National Product

– gigahertz (109 cycles per second)

– gigawatt (109 watts)

GEO

HEAO-C

HEL

HEW

HF

HFAL

HLLV

HRP

HVTL

Hz

HZE

IAF

ICBM

IEA

IEEE

ISM

ITU

kg

km

k w

laser

LEO

LMFBR

LORAN

MHz

MPTS

M W

mW/cm2

NAS

NASA

NATO

NBS

NIEMR

NIOSH

NRDC

OECD

– geostationary orbit

– High Energy Astronomical

Observatory-C

– high-energy laser

– Department of Health, Education and

Welfare

– high frequency

– high frequency auditory limit

– heavy-lift launch vehicle

– horseradish peroxidase

– high-voltage” transmission line

—

—

—

—

—

—

—

—

—

—

hertz: a unit of frequency equal to

one cycle per second

high-atomic-number, high-energy

particles

International Astronautical Federation

intercontinental ballistic missile

International Energy Agency

Institute of Electrical and Electronics

Engineers

industrial, scientific, and medical

International Telecommunication

Union

kilogram

kilometer

kilowatt (103 watts)

light amplification by stimulated

emission of radiation

– low-Earth orbit

– liquid metal fast breeder reactor

– long-range navigation

– Megahertz (106 cycles per second)

— microwave power transmission system

— megawatt (10’ watts)

— milliwatts per square centimeter

— National Academy of Sciences

– National Aeronautics and Space

Administration

— North Atlantic Treaty Organization

– National Bureau of Standards

— nonionizing electromagnetic radiation

– National Institute of Occupational

Safety and Health

– Natural Resources Defense Council

– Organization for Economic

Cooperation and Development

(United States, Canada, Japan, West

Europe)

OMEGA — generic name for long-range

navigation

OPEC – Organization of Petroleum Exporting

Countries

293
294 • Solar Power SateLLites

OSHA

OTA

PLV

POTV

prf

Q

Qe

R&D

rem

RFP

– Occupational Safety and Health

Administration

– Office of Technology Assessment

– personnel launch vehicle

– personnel orbital transfer vehicle

— pulse repetition frequencies

– Quad (quadrillion BTUS)

– Quad, electric

— research and development

– Roentgen equivalent man, the

quantity of ionizing radiation whose

biological effect is equal to that

produced by one roentgen of X-rays

— radiofrequency radiation

SAM

SAR

SEPS

SPS

SRBC

SSTO

STS

t

TVA

UHF

VER

VHF

W HO

— surface to air missile

— specific absorption rate

— solar electric propulsion system

— solar power satellite

— sheep red blood cells

— single stage to orbit space vehicle

— space transportation system

— metric ton (tonne); 1,000 kg

– Tennessee Valley Authority

— ultra high frequency

— visually evoked electrocortial

response

— very high frequency

— World Health Organization
Glossary

Ablate—to remove by cutting, erosion, melting,

evaporation, or vaporization.

Aerosol—a suspension of insoluble particles in a

gas.

Albedo–the fraction of incident light or electromagnetic radiation that is reflected by a surface

or body.

Ambient—the natural condition of an environmental factor.

Amplitude–the maximum departure of the value

of an alternating wave from the average value.

Artifact— a product of artificial character due to an

extraneous agent.

Attenuation– a reduction in amplitude of electromagnetic energy.

Beam width–the angular width of a beam of radiation, measured between the directions in which

the power intensity is a specified fraction, usualIy one-half, of the maximum.

Bias current–the electric current applied to a

device (e.g., a transistor) to establish a reference

level for operation.

Biota—the plants and animals of a region.

Brayton cycle— a method of driving a turbine in

which a gas is compressed and heated. The

most familiar use is for aircraft gas turbine

engines. An alternative to the Rankine cycle.

Bremsstrablung radiation– radiation from charged

particles that are decelerated in a magnetic

field.

British thermal unit-quantity of heat needed to

raise one pound of water one degree Fahrenheit

at or near 39.2 ‘F.

Circadian–pertaining to events that occur at approximately 24-hr intervals, such as certain biological rhythms.

Cloud condensation nuclei (CCN)–particles on

which water vapor condenses to form water

droplets, that in turn form clouds and fogs.

Convection-circulatory motion that occurs in the

atmosphere due to nonuniformity in temperature and density, and the action of gravity.

Cortical tissues–tissue from the outer layer of gray

matter of the brain.

Cosmic ray–atomic nuclei of heterogeneous, extremely penetrating character that enter the

Earth’s atmosphere from outer space at speeds

approaching that of Iight.

Coupling–the mechanism by which electromagnetic energy is delivered to a system or device.

CW laser–continuous wave laser, as distinguished

from a pulsed laser. A laser emitting for a period in excess of 0.25 second.

Cytogenetics– a branch of biology that studies

heredity and variation by the methods of both

cytology and genetics.

Cytology– a branch of biology dealing with the

structure, function, multiplication, pathology,

and Iife history of cells.

Decible– a unit for expressing the ratio of two

amounts of electric or acoustic signal power

equal to 10 times the common logarithm of this

ratio. A ratio of 10 is 10 dB, a ratio of 100 is 20

dB, a ratio of 1,000 is 30 dB, etc.

Diffuse reflection— reflection of a beam incident on

a surface over a wide range of angles.

Dosimeter– a device for measuring doses of radioactivity.

Ecliptic–the circle formed by the apparent yearly

path of the Sun through the heavens; inclined

by approximately 23.50 to the celestial equator.

Electromagnetic energy– energy in the entire range

of wavelengths or frequencies of electromagnetic radiation extending from gamma rays to

the longest radio waves and including visible

light.

Electron— a subatomic particle with a negative

electrical charge.

Endocrinology– a science dealing with the endocrine glands, which produce secretions that are

distributed in the body by way of the bloodstream.

Energy dose– the quantity of electromagnetic

energy (in joules) that is imparted per unit of

mass to a biological body.

Energy dose rate— the amount of electromagnetic

energy that is imparted per unit of mass and per

unit of time to a biological body.

Epidemiology-a branch of medical science that

deals with the incidence, distribution, and control of disease in a population.

Extended source—an extended source of radiation

that can be resolved into a geometrical image

in contrast with a point source of radiation, that

cannot be resolved into a geometrical image; a

source that subtends an angle greater than one

arc min.

Exosphere–the outer fringe region of Earth’s atmosphere.

Field intensity–the magnitude of the electric field

in volts per meter or the magnitude of the magnetic field in amperes per meter.

Flux–the rate of transfer of particles or energy

across a given surface.

Frequency—the number of complete oscillations

per second of an electromagnetic wave, measured in hertz (Hz). One hertz equals one cycle

per second.

295
296 ● Solar Power Satellites

Geostationary Earth orbit (GEO)– the equatorial orbit at which a satellite takes 24 hr to circle the

Earth so that it is stationary as viewed from

Earth; altitude approximately 36,000 km.

Geosynchronous Earth orbit–the orbit at which a

satelIite takes 24 hr to circle Earth. (The satelIite

may or may not appear to be stationary above a

point on Earth.)

Harmonic frequency– a component frequency of an

electromagnetic wave that is a multiple of the

fundamental frequency.

Heliostat– a mirror device arranged to follow the

Sun as it moves through the sky and to reflect

the Sun’s rays on a stationary collector.

Hematology-a branch of biology that deals with

the blood and blood-forming organs.

Heavy-lift launch vehicle (HLLV)– a proposed launch

vehicle used to transport large masses of material from Earth to low- Earth orbit.

Illuminance– irradiance; rate of energy per solid

angle measured at a given point.

Immunology— a science that deals with disease resistance and its causes.

Intermodulation –the mixing of the components of

a complex wave with each other in a nonlinear

circuit. The result is that waves are produced at

frequencies related to the sums and differences

of the frequencies of the components of the

original waves.

Intrabeam viewing– viewing the laser source from

within the beam. The beam may either be direct

or specularly refIected.

Ion—an atom or group of atoms that carries a

positive or negative electrical charge as a result

of having lost or gained one or more electrons.

Ionizing radiation– radiation capable of producing

ions by adding electrons to, or removing electrons from, an electrically neutral atom, group

of atoms, or molecule.

Ionosphere—the part of Earth’s atmosphere beginning at an altitude of about 5 km extending and

outward 500 km or more, containing free electrically charged particles by means of which

radio waves are reflected great distances

around the Earth.

Irradiance (E)– radiant fIux density arriving at given

surface in units of watts-per-square-centimeter

(W/cm2

); illuminance (as measured by a detector).

Joule (J)– unit of energy (1 watt-see) under the international system. As a thermal unit, 1 joule

equals 0.239 calories. Since the calorie is defined as the energy required to heat 1 gram of

water from 40 to 50 C, 4.184 joules is the

equivalent of one calorie.

Kapton– Iightweight, tough plastic film.

Klystron— an electron tube used to generate and

amplify microwave current.

Laser– a device for generating coherent light radiation.

Low-Earth orbit (LEO) –altitude approximately 500

km.

Luminance–brightness on a light source, equal to

luminous flux per unit solid angle emitted per

unit area of the source.

Magnetron— a magneticalIy control led tube used

to generate and amplify microwave radiation;

the power sources for microwave ovens.

Magnetosphere– a region of Earth’s outer atmosphere in which electrically charged particles

are trapped and their behavior dominated by

Earth’s magnetic field.

Mass driver– an apparatus for accelerating material

in an electromagnetic field.

Mesoscale–on or relating to a meteorological phenomenon approximately 1 to 100 km in horizontal extent.

Mesosphere– a layer of the atmosphere extending

from the top of the stratosphere to an altitude

of about 80 km.

Microwave– a comparatively short electromagnetic wave, especialIy one between 100 cm and

1 cm in wavelength or, equivalently, between

0.3 and 30 GHz ‘in frequency.

Modulation–when a continuous series of waves of

electromagnetic energy is modified by pulsing,

or by varying its amplitude, frequency, or

phase, the waves are said, respectively, to be

pulse-, amplitude-, frequency-, or phase-modulated. In order to convey information by radiating electromagnetic energy, it must be modulated,

Morphology-a branch of biology that deals with

the form and structure of animals and plants.

Multibiotic– having or consisting of many plants

and animals.

Multipath radiation— in contrast with a so-called

plane wave, that flows in a straight line through

space, an area or volume where electromagnetic waves arrive from different directions

because of reflection or multiple sources is said

to be the site of multipath radiation.

Neuroendocrine-of, relating to, or being a hormonal substance that influences the activity of

nerves.

Neutral particles– molecules, atoms, or subatomic

particles that are not electrically charged.

Neutron–an uncharged elementary particle that

has a mass nearly equal to that of the proton
Glossary ● 2 9 7

and is present in all known atomic nuclei except

the hydrogen nucleus.

Noctilucent cloud— a luminous thin cloud seen at

night at a height of about 80 km.

Nonionizing radiation— radiation of too low an energy to expel an electron from a molecule or

atom.

Ohmic heating-a heating mechanism in a plasma

or other conducting medium. The free electrons

in the medium are accelerated by an applied

electric field and give up kinetic energy by collision with other particles.

Phase—the measure of the progression of a periodic wave in time or space from a chosen instant or position.

Phased array– an array of antennas that is aimed as

a group by adjusting the phase of the signal it

sends or receives.

Photoionization– ionization (as in the ionosphere)

resulting from CoIIision of a molecule or atom

with a proton.

Photoklystron — a device for directly converting visible light to microwave radiation.

Photon— a quantum of radiant energy.

Photoperiod – the interval in a 24-hr period during

which a plant is exposed to Iight,

Photovoltaic cell– a cell composed of materials

that generate electricity when exposed to light.

Plasma–a collection of charged particles exhibiting some properties of a gas but differing from a

gas by being a good conductor of electricity

and by being affected by a magnetic field.

Polarization–the electric (E) and magnetic (H) fields

that comprise a propagating electromagnetic

wave may be fixed in relation to Earth’s horizon, or they may rotate. By convention, the vector of the E field is related to Earth’s horizon: if

the two are perpendicular, the wave is said to

be vertically polarized; if parallel, horizontally

polarized. When the E and H fields are continuously rotating with respect to the horizon, the

wave is said to be elIipticalIy polarized.

Power–the quantity of energy per unit of time that

is generated, transferred, or dissipated. The unit

of power, the watt (W), is defined as one joule

per second (j/s).

Power density-the quantity of electromagnetic energy that flows through a given area per unit of

time. Formally, power density is specified in

watts per square meter (W/m2

), but by tradition

in biological effects studies it is usually expressed in milliwatts per square centimeter

(mW/cm2

).

Propagation —the transmission of electromagnetic

wave energy from one point to another.

Proton– an elementary particle that is identical

with the nucleus of the hydrogen atom, that

along with neutrons is a constituent of all other

atomic nuclei, that carries a positive charge numericalIy equal to the charge of an electron.

Pulsed laser– a laser that delivers its energy in short

pulses, as distinct from a CW laser; a laser

which emits for less than 0.25s.

Radiation pressure– all propagating electromagnetic waves exert a very sIight pressure on

an absorbing object.

Rankine cycle– a Iiquid gas cycle used often for

steam turbines. A working fluid is heated until it

expands and drives a turbine.

Rectenna– a coined term for the SPS reference system receiving antenna that also converts the

microwave power to direct-current electricity.

Rectification-the conversion of an alternating current to direct current.

Refraction– a deflection from a straight path undergone by a wave in passing obliquely from one

medium into another in which its velocity is different.

Root-mean-square—for an alternating voltage, current, or field quantity: the square root of the

mean of the square of the quantity during a

complete cycle.

Scattered power– power that is reflected or dispersed as the result of an obstruction in the

path of the primary power flow.

Side lobe— refers to power radiated from an antenna in a direction other than the desired direction of transmission.

Slipring–a metal ring to conduct current in or out

of a rotating member of a machine.

Solar flare– an explosion on the Sun which generates fast elementary particles.

Solar wind–a stream of particles generated by a

solarfIare.

Solid-state amplifier– an amplifier whose operation

depends on a combination of electrical effects

within solids, e.g., a transisterized amplifier for

electromagnetic waves.

Specific absorption rate (SAR)–the quantity of electromagnetic energy that is absorbed by a body

per unit of mass during each second of time; expressed formally in watts per kilogram (W/kg);

often, informally as milliwatts or watts per

gram (m W/g or W/g). “Specific absorption rate”

is being considered by the National Council on

Radiation Protection and Measurements as the
298 • Solar Power Satellites

official nomenclature for expressing the dose

rate of radio-frequency electromagnetic radiations. Synonymous with energy dose rate.

Specular or regular reflection– a mirror-like reflection.

Spurious power or frequency–electromagnetic energy produced at frequencies that are not easily

related to a specified operating frequency.

Stratosphere– an upper portion of the atmosphere

above approximately 10 km (depending on latitude, season, and weather) and in which temperature changes little with changing attitude

and clouds of water are rare.

Sun-synchronous orbit– a near polar orbit which

keeps the satellite in full sunlight all the time

while Earth rotates beneath it.

Susceptibility—the sensitivity of an electromagnetic

receiver to undesired electromagnetic waves

that may resuIt in interference.

o

Symptomatology– a branch of medical science concerned with symptoms of diseases.

Teratology-the study of malformation or serious

deviations from the normal development of

fetuses.

Thermosphere–the part of Earth’s atmosphere that

begins about 80 km above Earth’s surface, extends to outer space, and is characterized by

steadily increasing temperature with height.

Troposphere– the portion of the atmosphere below

the stratosphere, which extends outward about

15 km from Earth’s surface, and in which temperature generally decreases rapidly with

altitude.

Van Allen belt— a belt of intense ionizing radiation

that surrounds Earth in the outer atmosphere.

Wave guide– a device for transmitting and guiding

radio-frequency waves