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i

iii

Strategic Studies Institute

and

U.S. Army War College Press

SPACE-BASED SOLAR POWER:

A TECHNICAL, ECONOMIC, AND 

OPERATIONAL ASSESSMENT

Jeffrey L. Caton

April 2015

The views expressed in this report are those of the author and 

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offer new and sometimes controversial perspectives in the interest of furthering debate on key issues. This report is cleared for 

public release; distribution is unlimited.

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Sections 101 and 105. It is in the public domain and may not be 

copyrighted.
iv

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ISBN 1-58487-668-9
v

FOREWORD

With growing international awareness of energy 

security challenges, the promise of space-based solar 

power for clean and unlimited energy for all humankind is certainly appealing. While significant progress 

continues in the enabling technologies of such systems, is there compelling evidence that space-based 

solar power systems will provide the best energy 

solution? How does the Army’s current approach to 

incorporating a diverse portfolio of renewable energy 

sources in distributed locations compare with the potential of enterprise ventures that beam energy from 

solar collectors in space? 

For more than 4 decades, many credible organizations in government and industry have explored the 

concept of space-based solar power. But their serious 

studies often conclude that such systems remain on 

the future horizon, usually at least 10 years away from 

practical application. This monograph posits that, 

while space-based solar power systems may be technically feasible, there is no compelling evidence that 

such systems will be economically or operationally 

competitive with terrestrial-power generation systems 

in use or in development. However, this monograph 

does find that there may be some utility in the limited 

application of space-based solar power to enable operations in remote and forward operating locations.

 DOUGLAS C. LOVELACE, JR.

 Director

 Strategic Studies Institute and

 U.S. Army War College Press

vii

ABOUT THE AUTHOR

JEFFREY L. CATON is President of Kepler Strategies, 

LLC, Carlisle, PA, a veteran-owned small business 

specializing in national security, cyberspace theory, 

and aerospace technology. He is also an Intermittent 

Professor of Program Management with Defense Acquisition University. From 2007 to 2012, Mr. Caton 

served on the U.S. Army War College faculty, including Associate Professor of Cyberspace Operations and 

Defense Transformation Chair. Over the past 5 years, 

he has presented lectures on cyberspace and space 

issues related to international security in the United 

States, Sweden, the United Kingdom, Estonia, and 

Kazakhstan, supporting programs such as the Partnership for Peace Consortium and the North Atlantic 

Treaty Organization Cooperative Cyber Defence Center of Excellence. Mr. Caton’s current work includes 

research on cyberspace and space issues as part of the 

External Research Associates Program of the Strategic 

Studies Institute as well as serving as a facilitator for 

Combined/Joint Land Force Component Commander 

courses at the Center for Strategic Leadership and Development. He served 28 years in the U.S. Air Force 

in engineering, space operations, joint operations, 

and foreign military sales, including command at the 

squadron and group level. Mr. Caton holds a bachelor’s degree in chemical engineering from the University of Virginia, a master’s degree in aeronautical 

engineering from the Air Force Institute of Technology, and a master’s degree in strategic studies from 

the Air War College.

ix

SUMMARY

The concept of generating electrical power from 

solar energy using satellites and then transmitting 

that power to Earth is decades old and generally considered to be technically feasible. If successful, such 

systems could provide constant access to almost unlimited power and thus play a significant role in U.S. 

national and international energy security strategies. 

However, the practical application of this method of 

power generation requires economical and operational feasibility as well. This monograph examines 

the current progress of space-based power in these 

three areas: technology, economy, and operations. 

The scope of discussion is at the survey level of detail 

to provide senior policymakers, decisionmakers, military leaders, and their respective staffs an overall appreciation for the challenges, opportunities, and risks 

associated with space-based solar power systems.

This monograph has three main sections:

1. Technical Assessment. This section introduces 

the basic concept of space-based solar power (SBSP). It 

then summarizes the evolution of the concept’s development, as documented in six major reports written 

over the past 37 years. Finally, the section examines the 

critical technologies required for the successful development of the space, ground, and support elements of 

the system.

2. Economic Assessment. This section examines 

SBSP system cost estimates from a variety of sources. 

It then compares these costs to competing alternative 

energy solutions such as terrestrial-based photovoltaic power plants. The section also addresses regulatory 

factors that may affect the development and operation of SBSP systems as well as current international 

efforts in this field.
3. Operational Assessment. This section explores 

the strategic considerations for SBSP systems within 

the general context of national space operations. It then 

examines potential garrison-level applications and 

compares these with the current plans of the Army’s 

Energy Initiatives Task Forces to integrate terrestrialbased photovoltaic power into the energy systems of 

several major installations. Finally, the section briefly 

explores possible SBSP applications to support remote 

operating locations.

x
1

SPACE-BASED SOLAR POWER: 

A TECHNICAL, ECONOMIC, AND 

OPERATIONAL ASSESSMENT

The concept of generating electrical power from 

solar energy using satellites and then transmitting 

that power to Earth is decades old and generally considered to be technically feasible. However, the practical application of this method of power generation 

requires economical and operational feasibility as 

well. This monograph examines the current progress 

of space-based power in these three areas: technology, 

economy, and operations. 

TECHNOLOGICAL ASSESSMENT

This section introduces the basic concept of spacebased solar power (SBSP). It then summarizes the evolution of the concept’s development, as documented 

in six major reports written over the past 37 years. 

Finally, this section examines the critical technologies 

required for the successful development of the space, 

ground, and support elements of the system.

Concept.

The idea of harnessing the power of the sun in 

space and transferring that energy to Earth is older 

than the first U.S. satellite. Initially conceived in the 

realm of the imagination, the idea soon gained the attention of serious scientists. In 1968, Dr. Peter Glaser 

publicly presented his research in the area of spacebased solar power at the Intersociety Engineering 

Energy Conversion Conference.1

 Three years later, he 

filed for a U.S. patent for a “Method and Apparatus 
2

for Converting Solar Radiation to Electrical Power,” 

which was granted in 1973. In the patent document, 

Glaser emphasized the problems of pollution and 

waste management caused in energy production using fossil and nuclear fuels as well as the limited supply of each on the planet. He argued that his invention 

would overcome many of the practical limitations of 

generating electricity from solar power on the Earth, 

such as atmospheric absorption, cloud cover, and daynight cycles.2

The abstract for Glaser’s patent provides a concise description of the process and its key functional 

elements: “Solar radiation is collected and converted 

to microwave energy by means maintained in outer 

space on a satellite system. The microwave energy is 

then transmitted to Earth and converted to electrical 

power for distribution.”3

 Figure 1 provides a simple 

block diagram of this design with elements grouped 

by space systems (collect, convert, and transmit) and 

terrestrial systems (receive, convert, and utilize). 

These systems are connected by an electromagnetic 

(EM) link to achieve energy transfer using microwaves 

per the original design or using light amplification by 

stimulated emission of radiation (laser) as proposed in 

certain subsequent designs. The technological assessment in this paper will focus on these seven functions.
3

Figure 1. Key Functional Elements of a Space-Based 

Solar Power System.4

Evolution and Trends.

The U.S. Government’s interest in SBSP systems 

has waxed and waned over the years in large part due 

to the lack of urgent need for the capability—coupled 

with very large investment requirements competing 

with other national needs. Hundreds of studies and 

reports have been written on the various details of the 

SBSP concept, but most of the content relevant to this 

monograph is contained in six comprehensive studies 

summarized here. 

Initial National Aeronautics and Space Administration 

Reports (1977 and 1980).

Less than 2 years after Glaser’s initial patent was 

granted, the National Aeronautics and Space Administration (NASA) George C. Marshall Space Flight 
4

Center initiated a contract in February 1975 for a 

three-phase study of SBSP concepts. The final report, 

“Space-Based Solar Power Conversion and Delivery 

Systems Study,” was published in March 1977. The 

study “examined potential concepts for a photovoltaic satellite solar power system, focusing on ground 

output power levels of 5,000 megawatts (MW) and 

10,000-MW, and a power relay satellite,” as well as 

economic issues related to their implementation.5

 If 

one considers that the 2012 net generation capability 

of the Three Mile Island nuclear plant was 829-MW, 

the scope of application envisioned by the NASA 

report was significant.6

The study had three major conclusions: (1) SBSP 

“is technically feasible and has economic potential”; 

(2) the economic potential provides justification for 

“a significant technology advancement and verification program”; and, (3) there remained “major areas 

of technological and economic uncertainty relating to 

decisionmaking.” The report highlighted four areas 

requiring further study: 

a) The fabrication and assembly of large structures in space; b) Solar energy conversion technology; c) The cost of electric power supplied 

by alternative energy sources; and, d) Constraints imposed by ionospheric and biological 

effects.7

As we will see, these specific areas of challenge remain largely unresolved by any practical demonstration. The cost estimate to procure a 5,000-MW SBSP 

system and deliver it to geosynchronous orbit (GEO) 

was $7.566 billion, with an estimated annual operations and maintenance cost of $1.156 billion (both 

costs based on 1974 dollar value). Of particular note 

for further discussion is that the costs for the space 
5

launch of the system ($3.278 billion) comprised over 

43 percent of the total procurement cost.8 The study 

also anticipated a constellation of 109 to 120 satellites, 

each with a service life of 30 years, with the prototype 

satellite on orbit within 10-15 years (1987-92).9 Overall, 

this study was extremely ambitious in its operational 

scope as well as very optimistic regarding the potential availability of funding. 

In the same year as the release of the first NASA 

SBSP report, the Department of Energy (DoE) initiated 

their Concept Development and Evaluation Program 

(CDEP) to work jointly with NASA in further examination of solar power satellite costs and benefits. In 

1980, DoE published its final report of the Solar Power 

Satellite (SPS) Program Review. Open participation 

was encouraged from a broad audience, and the 

report included an impressive collection of over 170 

separate articles by subject matter experts organized 

into four general areas: Systems Definition, Environmental, Societal, and Comparative Assessments. To 

help integrate the myriad technical details of the individual studies, the report established a baseline SPS 

configuration that many subsequent reports refer to as 

the “1979 SPS Reference System.” This system’s major 

elements (depicted in Figure 2) are truly monumental 

in scale, with each satellite’s solar collector measuring 

50 square kilometers (KM), a transmitting space antenna that is 1-KM in diameter, and a terrestrial receiving 

antenna array measuring 10 by 13-KM.10 Despite having an estimated price tag of $13.5 billion (1977 dollar 

value) for the first satellite and an eventual unit cost of 

$11.5 billion—plus an estimated $89 billion in development costs—the report “bottom line” was that “no 

insurmountable barrier to the SPS concept have [sic] 

emerged. Significant technical, environmental and 

cost questions, however, have not been answered.”11
6

Figure 2. 1979 NASA/DoE Solar Power Satellite 

Reference System.12

NASA “Fresh Look” Report (1997).

After the Congressional Office of Technology Assessment determined in 1981 that the DoE/NASA SPS 

concept was “programmatically and economically 

unachievable,” U.S. Government efforts for SBSP development went dormant. During 1995-96, NASA decided to examine the issue again from a “fresh look” 

perspective to see if new technologies might provide 

new solutions to existing SBSP challenges. The study 

considered 30 different SPS models as well as different 

orbital architectures, which included low Earth orbit 

(LEO) and medium Earth orbit (MEO) in addition to 

the 1979 standard placement in GEO. It re-addressed 

the major parts of the original DoE/NASA study including the space system, ground system, space infrastructure, and space transportation. Renowned SBSP 

expert and advocate John Mankins summed up the 

study’s conclusion:
7

space solar power concepts may be ready to reenter 

the discussion. Certainly, solar power satellites should 

no longer be envisioned as requiring unimaginably 

large investments in fixed infrastructure before the 

emplacement of productive power plants can begin.13

Of course, Mankins went on to caveat that this 

optimistic economic view required “the successful 

development of various new technologies—not least 

of which is the availability of exceptionally low cost 

access to space.”14

In 1999, NASA established the Space Solar Power 

(SSP) Exploratory Research and Technology (SERT) 

program to further explore some of the claims of the 

“Fresh Look” report, focusing on technologies needed to make the concept competitive with traditional 

ground-based power plants. In addition, it was: 

also expected to provide a roadmap of research and 

technology investment to enhance other space, military, and commercial applications such as satellites 

operating with improved power supplies, free-flying 

technology platforms, space propulsion technology, 

and techniques for planetary surface exploration.15

Accordingly, SERT used a series of model system 

categories (MSCs) of experimentation demonstrations to integrate its research efforts. The MSC designs 

ranged from relatively small-scale satellites to deliver 

100-KW of power from LEO; to megawatt-range satellites that could “fly” from Earth LEO to GEO as well 

as interplanetary; up to the gigawatt (GW)-range satellites required for commercial power generation. The 

overall goal was to use a constellation of 1.2-GW satellites to deliver 10-100-GW of power for commercial 
8

use on Earth. Even with an extremely optimistic space 

lift cost, each satellite was estimated to incur $14 billion for transportation to operational orbit.16 In March 

2000, NASA asked the National Research Council 

to conduct an independent assessment of its SBSP 

programs; the group’s final report concluded: 

The committee has examined the SERT program’s 

technical investment strategy and finds that while the 

technical and economic challenges of providing space 

solar power for commercially competitive terrestrial 

electric power will require breakthrough advances 

in a number of technologies, the SERT program has 

provided a credible plan for making progress toward 

this goal. The committee makes a number of suggestions to improve the plan, which encompass three 

main themes: (1) improving technical management 

processes, (2) sharpening the technology development 

focus, and (3) capitalizing on other work. Even if the 

ultimate goal—to supply cost-competitive terrestrial 

electric power—is not attained, the technology investments proposed will have many collateral benefits for 

nearer term, less-cost-sensitive space applications and 

for nonspace use of technology advances.17

National Space Security Office Report (2007).

In March 2007, the National Space Security Office 

(NSSO) Advanced Concepts Office initiated a collaborative study to examine the potential benefits of SBSP 

systems from the perspective of national energy and 

enviromental security threats and opportunities. Its 

approach “relied heavily upon voluntary Internet discussions by more than 170 academic, scientific, technical, legal, and business experts around the world.”18

The stated research question was: 
9

Can the United States and partners enable the development and deployment of a space-based solar power 

system within the first half of the 21st century such 

that, if constructed, it could provide affordable, clean, 

safe, reliable, sustainable, and expandable energy for 

its consumers?19

The report “Space-Based Solar Power as an Opportunity for Strategic Security” addressed many aspects of this question by building upon the conceptual 

frameworks established in early NASA and DoE reports. It also addresses the study’s operational goal to 

deliver 5-10-MW of power to remote locations (vice 

designated terrestrial power stations) as well as the 

strategic goal to deliver 10 percent of all U.S. power 

by 2050.20

The NSSO report presented a more aggressive development option for a large-scale SBSP system demonstrator than the 25-year roadmap offered by NASA. 

NSSO’s new roadmap consisted of three phases over 

10 years, culminating in an SBSP satellite in orbit capable of delivering 10-MW of energy to Earth with a 

program cost of no more than $10 billion.21 To provide a sense of scale for NASA’s proposed system, 

the report noted that the largest structure currently 

in orbit, the International Space Station, had a mass 

of 232 metric tons (MT), which included solar panels 

that produce 112-KW of energy. The study’s design 

was much larger; “a single Space Solar Power Satellite 

is expected to be above 3,000-MT, several kilometers 

across, and most likely be located in GEO . . . likely delivering between 1 to 10-GWe [gigawatts electrical].”22

With such large and heavy satellites, it is reasonable 

the study considered “that launch cost is the single 

most important driver of the business case for SBSP,” 

requiring these costs to be as low as $200 per pound 
10

to make the system competitive with traditional commercial energy provider rates of about 10 cents per 

kilowatt-hour.23 NASA estimates the current price of 

space launch to be approximately $10,000 per pound 

to orbit, but its Advance Space Transportation Program aims to reduce this cost to hundreds of dollars 

per pound within 25 years.24

The report concluded that “the technical feasibility of the concept has never been better” but also admitted that “several major challenges will need to be 

overcome to make SBSP a reality, including the creation of low-cost space access and a supporting infrastructure system on Earth and in space.” With regard 

to military operations, the report noted that “for the 

DoD [Department of Defense] specifically, beamed 

energy from space in quantities greater than 5-MWe 

has the potential to be a disruptive game changer on 

the battlefield.” The report envisioned applications 

of SBSP energy being delivered to provide support 

across the spectrum of operations, such as providing 

energy on demand to forward-deployed combat units 

and ultra-long-duration surveillance drones, as well 

as rapid power delivery for disaster relief or nationbuilding efforts.25

Naval Research Laboratory Report (2009).

The 2007 NSSO report helped to motivate management at the Naval Research Laboratory (NRL) to 

examine the potential benefits of SBSP with a formal 

study “to determine if the NRL can offer a unique, 

cost-effective, and efficient approach to supplying significant power on demand for Navy, Marine Corps, 

or other DoD applications.”26 The final report findings 

were presented in four areas, three of which were similar to previous reports—concept feasibility, relevant 
11

research areas, and recommended course forward. 

In general, the report agreed that SBSP was technically feasible, but that there remained significant areas of technical, operational, and economic risk.27 It 

also highlighted how NRL might help reduce some 

of these risks, noting that “research applied to the areas in which NRL has core competencies would yield 

substantial technological dividends for SBSP as well 

as other space and terrestrial applications.”28

The NRL report included an area of findings dedicated to military operations scenarios. This included 

providing power to forward-operating locations that 

the report considered the best SBSP defense application; it was rated as possible for technical and economic feasibility, with development costs estimated at 

$10 billion and a development time of at least 5 years. 

An application with similar assessments was that of 

providing power to an unmanned air vehicle to prolong its dwell time. Providing power to individual 

warfighters was also considered, but it was assessed 

as unlikely for both technical and economic feasibility, due to power inefficiency, precise beam control 

requirements, and safety concerns for extended exposure to the energy transfer beam.29 The full summary 

of possible military scenarios and their assessments is 

included as Appendix 1. 

International Academy of Astronautics Report (2011).

In September 2007, the International Academy 

of Astronautics (IAA) completed a proposal for the 

first truly comprehensive international study of SBSP 

concepts. The goal of the study was: 

to determine what role solar energy from space might 

play in meeting the rapidly growing need for abun-
12

dant and sustainable energy during the coming decades, to assess the technological readiness and risks 

associated with the SPSS [space-based solar power 

systems] concept, and (if appropriate) to frame a national international roadmap.30

Two years later, the results of the study were presented in the International Symposium on Solar Energy from Space in Toronto, Canada. The study was 

comprehensive; its results were organized into seven 

areas: satellite system concepts; supporting systems; 

technology readiness and risk assessment; policy, legal, and regulatory considerations; market assessment 

and economics; preliminary system analysis; and international roadmap. However, the overall report 

summary sounded familiar: 

As of 2010, the fundamental research to achieve technical feasibility for the SPS was already accomplished. 

Whether it requires 5-10 years, or 20-30 years to mature the technologies for economically viable SPS now 

depends more on (a) the development of appropriate 

platform systems concepts, and (b) the availability of 

adequate budgets.31

The study’s detailed findings included themes that 

were familiar from previous reports, such as “low-cost 

Earth-to-orbit transportation is an enabling capability 

to the economic viability of space solar power for commercial base load power markets.”32 The findings also 

addressed the desire for SBSP energy to integrate with 

existing terrestrial power distribution systems as well 

as concerns for the resolution of policy and regulatory 

issues surrounding the transmission of energy from 

space to the Earth. The proposed technology roadmap 

emphasized experiments and demonstrations and 

noted that: 
13

timely success seems more likely to result from cooperation in accomplishing R&D [research & development] objectives among governments, among industry players and among a broad range of government, 

corporate and academic organizations.33

NASA Innovative Advanced Concepts Program 

Report (2012).

Almost a decade after NASA’s SERT program 

completed its 2-year study, the NASA Innovative Advanced Concepts (NIAC) Program approved a grant 

to explore a new SBSP design that might resolve any 

remaining technological and economic uncertainties. 

The concept that emerged was the Solar Power Satellite via Arbitrarily Large Phased Array (SPS-ALPHA), 

an innovative approach that leveraged modular design and autonomous robotics to address some of 

the challenges related to building large structures in 

space. It would use hundreds of thousands of standard hexagonal-shaped modules with various functions—reflecting, photovoltaic, or transmission—in 

concert with interconnecting devices and robotic arms 

to produce satellites of desired size and configuration. 

The envisioned assembly method would be cooperative behavior, such as that demonstrated by “a team 

of skydivers who cooperated to form quickly a large, 

complex structure during a jump.”34 The modular design could also reap the economic benefits of lower 

unit costs due to mass production and the small size 

of each module would simplify some of the physical 

challenges of space launch.

Potential applications proposed for SPS-ALPHA 

included not only commercial power generation, 
14

but also “National Security Premium Niche Power 

Markets” that:

may emerge due to military operations, or because of 

a requirement for short-term emergency operations 

(e.g., to support relief operations in the aftermath of a 

major national disaster, such as an earthquake, a tsunami, etc.).35

In economic terms, the report’s conclusion looks 

promising: 

The roadmap for SPS-ALPHA appears quite tractable 

programmatically: the hyper-modular architecture 

should enable fast-paced, relatively inexpensive steps 

forward, with a total cost for a scalable solar power 

satellite pilot plant of about $5B and the first full-scale 

SPS of roughly $20B. These numbers are substantial, 

but compare well to the reported $100B cost of the ISS 

or the earlier 1980s era estimates of roughly $1,000B to 

reach the first SPS [cost adjusted for inflation from c. 

1980 to c. 2012].36

However, the report also admits that these estimates have a familiar assumption: 

As has been found in past studies and for other SPS 

concepts going back to the 1970s, ETO [Earth-to-orbit] 

transportation remains a critical factor in realizing 

economically viable SPS for terrestrial markets.37

Critical Technologies.

From the overview of previous major studies, it is 

clear that there is no single or best-design concept for 

SBSP systems. Results from the research and development of individual components and subsystems could 

fill libraries, but from this diverse work, certain tenets 
15

have emerged with regard to critical SBSP technologies.38 This section addresses such matters for a typical system’s key functional elements as depicted in 

Figure 1. It then introduces the major support systems 

required for practical SBSP operations and highlights 

the related unique or critical technologies. The focus is 

on the assessment of feasibility and operational appropriateness to support decisionmaking and not on the 

understanding of scientific or engineering nuances. 

Space System.

From a survey of the literature, there is general 

agreement in the technical community that SBSP 

systems technically feasible and require no scientific 

breakthroughs to operate. This is not to say that all 

required technologies are readily available, but rather 

that there is high confidence that they can be developed for practical application in a reasonable time 

with reasonable risk.39 Thus, the focus in space system design turns toward the identification and optimization of performance parameters to distinguish 

operational utility among many different design alternatives. For example, factors such as component durability and efficiency may be balanced against their 

cost and weight.

The components of a space system as depicted in 

Figure 1 involve relatively mature technologies and 

pose low risk for development and operation. Solar 

radiation collection will require large reflectors using established basic material and structural design 

practices, with risk increasing with the size of the assembly. Solar power conversion can leverage various 

proven forms of photovoltaics—individual cells that 

convert solar radiation to electricity—that have been 

used on satellites for over 50 years. The efficiency of 
16

this conversion is a driving factor in the selection, but 

these efficiencies will degrade with continuous exposure to the sun, with the performance reduction different for each cell design and material.40 Unlike today’s 

satellites, which use flat photovoltaic arrays almost 

exclusively, SBSP satellites would need to have the 

solar collectors concentrate sunlight to near the maximum capacity for the solar cells to further increase the 

overall system efficiency.41

The wireless energy transmission subsystem has 

received considerable attention in every major SBSP 

study. The two most popular choices are either microwave or laser transmission subsystems. Microwaves 

have the advantage of significantly better efficiencies 

but require very large transmitting antennae, which, 

in turn, drive the need for large receiving antennae 

on the ground. Lasers are more compact and require 

much smaller ground receivers, but this drives the 

need for more accurate beam pointing. Also, the lower 

efficiencies of laser operation mean that considerably 

more energy is wasted in the form of heat than with 

microwave systems, and this heat must be managed 

as part of the satellite operation.42 One innovative 

solution to the transmission challenge is to combine 

it with the sunlight-conversion process in a modular 

design. The NRL has built and tested such a design 

called the “sandwich module,” in which “one side 

receives solar energy with a photovoltaic panel, electronics in the middle convert that direct current to a 

radiofrequency, and the other side has an antenna to 

beam power away.”43 This type of module is an essential part of the SPS-ALPHA design configuration, 

which envisions the use of hundreds of thousands of 

such components for each satellite.44

While most of the SBSP components may be low 

risk individually from a technological viewpoint, the 
17

systems integration effort required to make a viable 

satellite that can operate for decades is immense. The 

satellite must have an integrated structure (commonly 

called the “bus”) that includes power and thermal 

management systems; guidance, navigation, and control systems; telemetry, tracking, and control links; 

and stabilization and pointing systems. While it may 

be possible to leverage some of the design concepts 

of existing commercial GEO satellites buses, none of 

them can handle the size and mass of proposed SBSP 

applications.45 The requirements of an SBSP satellite 

bus would be even more challenging for concepts 

based on lower orbits (e.g., LEO or MEO), in which 

orientation between the satellite and the ground stations is constantly changing, compared with the relatively stable orientation of GEO satellites. 

Electromagnetic Link.

As mentioned, the electromagnetic (EM) link that 

provides wireless power transmission from the SBSP 

satellite and ground receiver would most likely be 

high-intensity microwave or laser beams. In theory, 

frequency ranges of 2.5 to 5.4 gigahertz (GHz) and 

35 to 38-GHz are optimal for such application. While 

most studies favor the lower-frequency range, the 

higher range requires much smaller transmission and 

reception antennae and will produce less ionospheric 

heating.46 Viable laser designs would operate in the 

near-infrared spectrum and would be generated using 

a solid-state electronic means vice chemical reaction. 

In either case, the operational design of the EM link 

must consider safety issues related to the propagation 

of such directed energy beams that may encounter 

other satellites, aircraft, or humans en route to its in-
18

tended ground receiver.47 The selection of the EM link 

source will have a significant impact on the design 

requirements of the satellite bus attitude control and 

stabilization systems, which are untried for such large 

structures. Even minor pointing and vibration errors 

become significant when they are projected across 

tens of thousands of miles. 

Terrestrial System.

Compared to the space system, the terrestrial 

system generally has much lower technical risk. For 

microwave transmission, the receiver would be a 

rectified antenna, also known as a “rectenna,” which 

would both receive the microwave energy and convert 

it into direct current electricity.48 For laser transmission, the receiver would likely be a series of mirrors to 

concentrate the laser energy and direct it to photovoltaic cells for conversion to direct current electricity. In 

either case, the ground power management and distribution subsystems necessary to utilize the converted 

energy are common to the existing utility industry. 

Since there are inefficiencies inherent in either ground 

conversion process, the ground station must include 

thermal management to cool its components. Since the 

system is designed to always have access to energy 

from the sun, it may require temporary power storage on Earth for times of temporary satellite operation 

disruption or when the utility grid may not be able to 

accept all of the energy generated.49

Supporting Systems. 

Thus far, we have only considered the elements of 

an SBSP system in a theoretical design configuration; 

to examine it in a realistic operational environment 
19

we must also consider the supporting infrastructure 

required to deploy, operate, and maintain the system. 

Figure 3 depicts the SBSP system block diagram within this more holistic context. 

Figure 3. Space-Based Solar Power System

with Supporting Infrastructure.

For the space system, the transportation to orbit of 

such a large satellite is unprecedented and may take 

literally hundreds of current state-of-the-art space 

launches to achieve.50 The on-orbit assembly of the 

satellites is very high risk and deserving of its own detailed discussion beyond the scope of this monograph. 

The original NASA 1979 SPS Reference System included a reusable space freighter to carry astronauts to a 
20

LEO construction depot where components were to 

be assembled and then transferred to GEO.51 Contemporary studies have delegated these tasks to robotic 

devices yet to be designed, built, or tested. Once the 

system is fully deployed in space, it must be supported by routine satellite telemetry, tracking, and control 

(TT&C) facilities on Earth to monitor and maintain the 

health and station keeping of the satellite as well as 

direct operations of the SBSP payload. This is not a 

trivial matter; it requires ground facilities with TT&C 

transmitters and receivers as well as the equipment, 

procedures, and trained personnel to accomplish the 

tasks. Finally, the use of on-orbit maintenance would 

be necessary to ensure effective operation of the SBSP 

satellite with design lives of 10 years or more in the 

hazardous space environment that may induce damage through impact with micrometeoroids or masses 

of charged particles ejected by the sun.

The terrestrial systems infrastructure is more 

straightforward. It will require the construction and 

maintenance of a nature similar to that of existing 

photovoltaic solar power farms, but on a much greater 

scale. However, these systems may also require environmental impact studies of much greater detail than 

existing solar farms due to the increased intensity of 

the microwave or laser energy that they harvest. Of 

course, the terrestrials systems will also require the 

proper equipment, procedures, and trained personnel 

necessary for operations and maintenance. Finally, 

there needs to be a program of continuous research, 

development, test, and evaluation (RDT&E) supporting all of the space and terrestrial system activity. The 

RDT&E effort would not only support the initial design and deployment of the systems, but also would 

conduct programs such as component aging surveil-
21

lance and technology insertion to optimize performance throughout the system life cycle.

ECONOMIC ASSESSMENT

This section examines SBSP system cost estimates 

from a variety of sources. It then compares these costs 

to competing alternative energy solutions such as terrestrial-based photovoltaic power plants. This section 

also addresses regulatory factors that may affect the 

development and operation of SBSP systems as well 

as current international efforts in this field.

Estimated Cost Assessments.

The cost estimates for SBSP systems included in 

some of the studies already discussed do not follow 

any standard format. Thus, a direct comparison of 

their values among alternate systems is not possible. 

Instead, let us assess the estimates that are available 

for their magnitude and completeness. Table 1 is a 

summary of the system-level cost estimates extracted 

from the indicated reports as well as from two recent 

master’s degree theses. To aid with assessment, the 

original estimates have also been converted to 2013 

dollars. In cases where a range of value was given 

for the estimate, the lower cost was selected; thus, 

the costs in Table 1 reflect the best-case scenarios. For 

comparison to contemporary utility rates, a cost for 

each kilowatt-hour (kWh) was calculated for both 10-

year and 30-year system lives. To stay with the bestcase theme, these values were calculated assuming 

continuous power product.

At first look, most of the designs have costs per 

kWh well under $1 over an expected duty life; some 
22

of them approach costs of 10 cents per kWh, which is 

currently a competitive rate for commercial residential power.52 However, with the exception of the last 

estimate, all values in Table 1 do not include the costs 

to develop, build, and operate the terrestrial power 

plant—a significant cost for the overall system. Also, 

all the U.S. Government studies presented assume 

significant reductions (at least 50 percent) in space lift 

costs as part of their estimates. Thus, the SBSP systems 

do not yet achieve the economic feasibility necessary 

to compete with existing commercial power producers. However, the ability to deliver power to remote 

locations may open niche markets in which premium rates may be charged that allow for a profitable 

SBSP system. 

Space-Based Solar Power (SBSP)

System Description

Estimated 

Cost 

(year 

basis)

Estimated 

Cost 

(2013)53

Estimated Cost per 

kilowatt-hour (2013)

10-year life 30-year life

DoE/NASA 1979 SPS Reference 

System (5 GW)54

Satellite system (per unit cost)

Satellite development 

Satellite annual operations 

(1977)

11.5 B

89.0 B

1.2 B

35.0 B

270.6 B

3.6 B

0.08

0.62

0.01

0.03

0.21

>0.01

NASA Fresh Look Study55

Sun Tower satellite (250-MW)

SolarDisc satellite (5-GW)

Launch cost to GEO56

(1997)

8 B

30 B

14 B

11.0 B

41.1 B

19.2 B

0.50

0.09

0.18

0.17

0.02

0.06

NSSO Study57

Development & demo satellite 

(10-MW)

(2007)

10.0 B 11.0 B 12.56 4.19

NASA NAIS SPS-ALPHA Study58

First full-scale satellite (1-GW)

Development roadmap

(2012)

20.0 B

30.0 B

20.0 B

30.0 B

0.23

0.34

0.08

0.11

Table 1. Comparison of Space-Based Solar Power 

System Cost Estimates.
23

Naval Postgraduate School Thesis 

(Chow)59

Alternative A satellite (110-MW)

Alternative B satellite (106-MW)

Alternative C satellite (65-MW)

(2013)

10.4 B

2.4 B

2.1 B

10.4 B

2.4 B

2.1 B

1.08

0.26

0.37

0.36

0.09

0.12

Toulouse Business School Thesis 

(Xin et al.)60

(full system cost)

European Space Agency (ESA) 

development (5-GW)

(2009)

265

275.9 0.63 0.21

Table 1. Comparison of Space-Based Solar Power 

System Cost Estimates. (cont.)

Even with the potential for profitable niche markets, the magnitude of investment required is staggering. The total development cost based on European 

Space Agency (ESA) estimates of over $275 billion (see 

last entry in Table 1) is more than the market value 

of Walmart Stores ($247 billion) and well beyond the 

fiscal year 2015 budgets for NASA ($17.5 billion) and 

the Department of Energy ($27.9 billion).61 Further, 

the net present value (NPV) calculated on several 

SBSP systems yielded negative values: -$72 billion for 

a 1-GW system and -59 billion for a 5-GW system. The 

negative NPV values mean that the systems will subtract that value from the investor over the lifetime of 

the project.62

It is not clear that reducing the scope of the SBSP 

power generation to match needs of niche markets—

for example, from 1-5-GW to 10-100-MW—would 

make the NPV calculations much better for investors, 

since many of the costs for research and development 

of the system components are the same.63 In any case, 

there will always be competitors in the renewable energy market—how do their values compare to those of 

SBSP systems?
24

Competing Alternative Energy Solutions.

The DoE Energy Information Administration (EIA) 

produces independent statistics and analyses that include capital and operating cost estimates for utility 

scale electricity generating plants. Making these reports available to the public can play an “important 

role in determining the mix of capacity additions that 

will serve future demand for electricity.” The analysis 

includes consideration of the overall context of commercial power vendors as well as potential investors 

by helping them “determine how new capacity competes against existing capacity, and the response of the 

electric generators to the imposition of environmental 

controls on conventional pollutants or any limitations 

on greenhouse gas emissions.”64 Their assessments 

include the traditional power generating sources of 

coal, natural gas, nuclear, and hydroelectric power. 

But the reports also address alternative and renewable sources such as biomass, wind, geothermal, and 

solar (thermal and photovoltaic), which are becoming more common as they mature in technology and 

affordability. 

Table 2 was developed using EIA estimates for terrestrial photovoltaic power plants, which have been 

scaled up to provide 1-GW capacity. However, Earthbound photovoltaic plants do not have the constant 

sunlight exposure of an SBSP system. Thus, to make 

the values more comparable to the estimates in Table 

1, an average capacity factor (the time a plant can 

actually produce a capacity) of 20 percent is used to 

increase the cost to the equivalent of full-time operation.65 For comparison purposes, the estimates in both 

Tables 1 and 2 are set to a common reference year for 

dollar value (2013). Interestingly, the estimated cost 
25

range of $20.3-20.9 billion for a 1-GW terrestrial photovoltaic capacity is about the same as the $20 billion 

estimate for the first full-scale SPS-ALPHA satellite 

(which does not include the terrestrial and support 

systems of the SBSP system). 

It may be difficult to convince investors to commit 

to an SBSP system that is undeveloped, unproven, and 

high risk when terrestrial systems that tap into the 

same renewable energy source already exist. Further, 

as the technology matures and applications spread, 

the capital costs for terrestrial photovoltaic decreased 

by 22 percent between 2010 and 2013. Environmentally, the systems are very clean, rated as generating 

zero amounts of nitrous oxide, carbon dioxide, or 

sulfur dioxide. 

Table 2. Terrestrial Solar Photovoltaic Power Plant 

Cost, 2013 Estimates.66

Regulatory Factors.

In addition to the cost of construction and operation, SBSP systems will most likely face considerable 

costs related to compliance with regulations of many 

Nominal 

Plant 

Capacity

Overnight Capital Cost Annual Operations & 

Maintenance Cost 30-year

O&M Cost

(1-GW 

Continuous) Each 

Plant

1-GW 

Capacity

1-GW 

Continuous

Each 

Plant

1-GW 

Capacity

1-GW 

Continuous

20-MW

(50 plants for 

1-GW) 83.7 M 4.2 B 20.9 B 0.6 M 27.6 M 137.8 M 4.1 B

150-MW

(7 plants for 

1-GW)

581.0 

M 4.1 B 20.3 B 3.7 M 25.9 M 129.6 M 3.9 B
26

forms. For simplicity, we can assume that the environmental regulations for construction of the SBSP 

terrestrial portion will be similar to that of a solar 

photovoltaic power generating plant. However, the 

routine and continuous propagation of high-energydensity microwave or laser beams require significant 

coordination. System radio frequencies will have to be 

evaluated and approved by the Federal Communications Commission (FCC) as well as the International 

Telecommunications Union (ITU). The potential of 

interference with civil aviation must be addressed by 

the Federal Aviation Administration (FAA) and the 

International Civil Aviation Organization (ICAO).67 In 

its evaluation of NASA’s SERT program, the National 

Research Council stated that “environmental, health, 

and safety issues are now recognized as essential concerns to be addressed as early in a program as possible.”68 This evaluation may include studies by the 

Environmental Protection Agency and the Occupational Safety and Health Administration that address 

the effects of long-term exposure to wireless energy 

transfer on plants, animals, and humans. 

There will also be policy, legal, and regulatory 

considerations for the SBSP space system. The transportation of SBSP satellites to orbit will require coordination with the Department of Commerce and the 

Department of State for proper licensing and enduring compliance with the International Traffic in Arms 

Regulations (ITAR). Launch and early orbit operations should be coordinated with the proper authorities within DoD, such as the U.S. Strategic Command 

Joint Force Component Commander for Space. Also, 

investors must realize that the geosynchronous orbit belt around Earth should be considered a limited 

resource. GEO positions are allocated by the United 
27

Nations ITU and are very competitive for services 

such as telecommunication and direct broadcasting. 

Figure 4 depicts the change in the GEO population in 

both volume and complexity from 1999 to 2011, during which period there were on average 26 spacecraft 

placed into GEO annually.69

Figure 4. Geosynchronous Orbit Spacecraft 

Population and Orbital Complexity.70

International Efforts.

The pursuit of practical SBSP systems is not exclusive to the United States. In 2001, the National Research Council noted significant: 

international involvement in SSP [space solar power] 

and found an optimistic global picture. Japan, France, 
28

Canada, Russia, Ukraine, Georgia, Italy, Belgium, 

Germany, India, Netherlands, China, and Singapore 

are among the countries engaged in at least some facets of SSP research, development, and technological 

demonstration.70a

A decade later, the worldwide involvement remained 

strong, as demonstrated in the diversity of participants 

in the IAA Space Solar Power study, which included 

members from Japan, France, Norway, Canada, Germany, and the European Space Agency.

Japan has one of the most serious SBSP development programs, having formally incorporated a Space 

Solar Power Program into its Basic Plan for Space Policy in 2009. This plan included a 5-year development 

and utilization plan:

[The Japanese] Government will examine the system 

for the development of space solar power program 

from a comprehensive point of view in collaboration 

with related institutions, and also conduct demonstration of technologies for the energy transmission 

technology in parallel. Based on the result, Government will conduct ample studies, then start technology demonstration projects in orbit utilizing ‘Kibo’ or 

small sized satellites within the next 3 years to confirm 

the influence in the atmosphere and system check.71

The Japan Aerospace Exploration Agency (JAXA) 

is spearheading an SBSP effort with “a technology 

road map that suggests a series of ground and orbital demonstrations leading to the development in 

the 2030s of a 1-gigawatt commercial system.”72 Some 

of its intermediate milestones include a 1-KW satellite experiment by 2017; a 2-MW satellite experiment 

by 2024; and a 200-MW demonstration power station 

by 2028.73
29

The ESA has conducted studies and development 

activities for several decades. Its approach has included objectives to identify “possible synergies between 

ground and space based power generation solutions” 

as well as other potential roles for SBSP systems, such 

as space exploration.74 In 2003, the ESA published a 

program to evaluate solar power from space in three 

phases: general viability; system architecture level 

trade-off; and technology focus and demonstrator 

mission selection.75

However, the work of the ESA Advanced Concept 

Team during the validation phase determined that 

while the SBSP systems were technically feasible, “terrestrial plants [are] advantageous over space plants 

until [outputs of] several tens of GWe” and that “preliminary data show little to no advantage for European 

only based concepts.”76 Accordingly, while ESA currently has not progressed to a larger SBSP program, 

countries within the European Union have embraced 

terrestrially based solar photovoltaic plants. These efforts have proceeded better than planned; the result 

of “cumulative installed capability at the end of 2010 

was over 29-GW, almost 10 times the original target.”77

Building on this success, the goal among 26 member 

states is to have this cumulative photovoltaic power 

generation up to 84.5-GW in 2020; this is equivalent 

to the output of approximately 100 Three Mile Islandclass nuclear power plants.78

Other countries that have expressed interest in 

SBSP systems include Russia, China, and India. The 

China Academy of Space Technology is reported to 

have a five-step roadmap that culminates with a commercial SBSP satellite in GEO by 2050. There is a detailed proposal for a U.S.-India cooperative development, but it has received little serious attention.79
30

OPERATIONAL ASSESSMENT

This section explores the strategic considerations 

for SBSP systems within the general context of national 

space operations. It then examines potential garrisonlevel applications and compares these to the current 

plans of the Army’s Energy Initiatives Task Forces to 

integrate terrestrial-based photovoltaic power into the 

energy systems of several major installations. Finally, 

this section briefly explores possible SBSP applications to support remote operating locations.

Strategic Considerations.

Is there a compelling national security requirement for SBSP systems? No such explicit mandate exists in U.S. capstone space strategy documents, nor is 

there any reasonable objective that implicitly points to 

such systems as having any priority in current plans. 

The National Security Space Strategy posits that “the 

current and future environment is driven by three 

trends—space is becoming increasingly congested, 

contested, and competitive.”80 The growth of Earth’s 

orbital population depicted in Figure 5 clearly shows 

the increasing congestion and its consequences, such 

as over 4,500 pieces of orbital debris resulting from a 

Chinese anti-satellite (ASAT) test in 2007 and the collision of a Russian satellite with a U.S. commercial 

Iridium satellite in 2009. Even though the population 

has reduced somewhat since then due to the routine 

reentry of such debris, the July 2014 orbital population 

still stands at 16,900, of which only 3,812 objects are 

payloads.81
31

Figure 5. Earth Satellite Catalog Growth 

(1958-2011).82

Any additional satellites operating in this environment will only exacerbate the risk of safe operations for all other satellites. So perhaps the compelling 

question for proposed SBSP systems is this: Do they 

have a mission unique enough to justify their operation in this environment? Or, perhaps, stated another 

way, are the capabilities and benefits provided by 

SBSP systems exclusive to space or can they be accomplished on the ground, albeit perhaps more inefficiently? Certain space missions, such as surveillance, 

weather observation, and navigation spacecraft must 

leverage the ultimate high ground of space. Like these 

satellites, SBSP systems would have to operate in the 

severe and dynamic environment of space radiation, 

charged particles, and planetary debris. They would 

also be vulnerable to physical, electromagnetic, and 

cyber attacks. Finally, any contemplated use of SBSP 
32

systems would have to address the reasonable concern regarding the perceived ability of such systems 

to be weaponized. 

But the competition for resources that SBSP systems 

must overcome is not restricted merely to gaining a 

location in orbit; these systems must also compete for 

supporting infrastructure with limited capacity, such 

as space lift, ground-tracking support, and satellite 

command facilities. Finally, the SBSP systems would 

have to compete for government budget resources in 

an era of desired fiscal austerity. For example, the $50 

billion cost for SPS-ALPHA development and first 

1-GW satellite (see Table 1) is more than the program 

cost of either a CVN 78 Gerald R. Ford-class aircraft 

carrier ($36.0 billion). It is also more than the United 

States Air Force’s new KC-46 tanker aircraft ($44.5 billion) and significantly more than the $19 billion Space 

Based Infrared Satellite System (SBIRS High), which 

includes GEO satellites necessary for missile warning 

and battlefield awareness missions.83

It is also important to consider that the SBSP 

concept does not represent the only potential gamechanging possibilities for energy security. Solving 

such problems as superconducting material or fusion 

energy generation would radically change the availability and use of electrical power on Earth. However, 

certain SBSP-related technologies, such as wireless 

energy transfer, merit further development; such systems could be used to distribute power to remote locations with limited infrastructure. 

Garrison Applications. 

Considering the expense and risk associated with 

current SBSP concepts, one may wonder if there are 

alternative options for using solar power as part of 
33

an overall energy portfolio. On September 15, 2011, 

Secretary of the Army John McHugh established the 

Energy Initiatives Task Force (EITF) “to serve as a 

one-stop shop for the development of cost-effective 

large-scale Army renewable energy projects.”84 The 

program was designed to address Army goals and 

federal mandates for enhanced energy security with 

an initial investment estimated at $7.1 billion over 10 

years to generate 2.1 million-MW hours of power annually85 (roughly the output of a 240-MW plant operating continuously). The current goal of the EITF is 

to deploy 1-GW of renewable energy projects by 2025 

using solar, wind, biomass, and geothermal energy 

generation technologies.86

Table 3. Army Sites for Terrestrial Solar 

Photovoltaic Power Plants.

Facility Facility Power 

Requirements (peak)

Planned Photovoltaic 

Power

Land Usage

(acres)

Fort Detrick, MD87 40-MW 18.6-MW 80

Georgia 3 x 3088

- Fort Benning

- Fort Gordon

- Fort Stewart

73-MW

37-MW

62-MW

30-MW

30-MW

30-MW

250

250 

250

Fort Huachuca, AZ89 23-MW 18-MW 155

Fort Irwin, CA90 28-MW 15-MW 600

Redstone Arsenal, AL91 75-MW 10-MW 188

Fort Stewart, GA (lease)92 62-MW 20-MW 111

TOTAL 400-MW

171.6-MW

(42.9 percent peak)

1884

(7.6 square 

kilometers)
34

Table 3 summarizes the current EITF efforts related to energy production using photovoltaic arrays 

at seven different Army garrisons in the continental 

United States. When fully implemented, the cumulative output of these plants will be about 172-MW, providing over 300,000-MW hours annually when operating at 20 percent average capacity.93 The longer-range 

EITF goal is to have 505-MW of photovoltaic capability available to Army garrisons by 2020. Comparing 

the land required for the photovoltaic array to that required for the rectifying antenna of the 1979 NASA/

DoE concept (see Figure 2), we find that the photovoltaic array can provide the equivalent of 1-GW continuous power using about 221-square KM compared 

to 102-square KM for the rectenna.94 However, since 

the photovoltaic system does not require a 50-squareKM satellite in geosynchronous orbit, one could argue 

that if the 1979 NASA/DoE vision had been followed, 

it would now be eclipsed by the advanced state of the 

art of terrestrial photovoltaics. 

Other factors also make terrestrial photovoltaic 

systems attractive. Their structure is co-located with 

the garrison that will use the power, thus reducing 

the extent of long-distance power distribution grid 

requirements. The distributed deployment also provides a more robust system, which is less susceptible 

to single-point failures or attacks. Also, since all of the 

system components are on the ground, the system can 

be more accessible for maintenance at lower cost as 

well as more flexible to incorporate design improvements or technology insertion opportunities. 
35

Field Applications.

As discussed earlier, the NRL conducted a cursory 

review of possible military applications for SBSP systems; a summary table of its findings is included in 

the Appendix 1. While the report rates the use of SBSP 

systems as possible for forward operating base (FOB) 

applications, the NRL analysis states that the infrastructure and support personnel requirements do not 

offer significant advantages over traditional generator systems that use high energy-density fuel and are 

portable and well understood by operators. Assuming that typical FOB power requirements are no more 

than 5-MW, it is reasonable to question why the FOB 

would need the elaborate and expensive support from 

a GW-class SBSP system.95 Even if a single GEO satellite could power multiple FOBs, it would only utilize 

a fraction of its potential capability. 

Other studies have explored the possible use of 

mission orbits other than GEO for SBSP satellite applications. A 2009 Lawrence Livermore National Laboratory (LLNL) study explored “a space-based system 

capable of delivering 1-MW of energy to a terrestrial 

receiver station, via a single unmanned commercial 

launch into Low Earth Orbit (LEO)” for an estimated 

cost of $500 million.96 But the operational effectiveness of such a system is severely limited by the LEO 

orbit, since the satellite only would be visible to the 

ground station for short periods. A 2012 thesis study 

at the Naval Postgraduate School calculated the actual 

viewing windows that a single ground power receiving station would have for SBSP systems stationed in 

four different orbits. Figure 6 depicts these orbits and 

provides their respective view times. The operational 

utility of the LLNL concept would be limited to less 
36

than 1 hour of power transmission each day, and this 

time would be distributed over five different orbital 

passes.97 While using a highly elliptical orbit may provide up to 14.6 hours of satellite visibility each day, 

the use of any orbit below GEO would require significantly more sophisticated satellite attitude control and 

mission planning, since the orientation of the satellite 

relative to the ground station would be constantly 

changing at rates far above those in a GEO orbit. 

Figure 6. Potential Space-Based Solar Power 

Satellite Orbital Parameters.98

Potential niche use of SBSP systems to provide 

power for field applications, such as ultra-long duration unmanned vehicles or special operations forces, 

is certainly an attractive capability for warfighters. 
37

But even if basic technical and economic challenges 

of SBSP systems are overcome, the remaining issues 

of power efficiency, beam-pointing controls, and 

beam-exposure hazards make such uses unlikely in 

the near future.99 Even if wireless energy transfer is 

perfected from terrestrial sources, it use will require 

a serious review of implications in the areas of doctrine, organization, training, materiel, leadership and 

education, and personnel and facilities.

FINDINGS AND RECOMMENDATIONS

This monograph addresses many issues related 

to the technical, economic, and operational feasibility and potential opportunities of space-based solar 

power systems. Based on the review of these systems, 

the monograph offers the following findings and 

recommendations:

• While there is general consensus among credible studies that SBSP systems are technically 

feasible given a decade of development, there 

is no compelling evidence that such systems 

will be economically competitive or have operational utility and effectiveness benefits over 

terrestrial power generation systems in use or 

in development.

• There is no compelling need or urgency for

SBSP systems articulated in current national 

security strategies or future roadmaps.

• Most reports that strongly advocate SBSP as

a technically viable and economically competitive technology for energy have substantial 

biases for the system benefits and underplay 

many potential challenges and hazards. Also, 

the cost estimates of these reports focus on the 
38

capital costs of the satellite portion of the overall system, which often make questionable assumptions regarding the unprecedented availability of space lift capability at significantly 

reduced cost. The credibility of such reports 

would be improved if they incorporated independent life-cycle cost estimates.

• SBSP should be considered part of a larger 

energy portfolio vice the exclusive energy approach advocated by some studies.

• The Army Energy Initiatives Task Force plan

for terrestrial solar photovoltaic power is a prudent investment that will provide many of the 

benefits of SBSP systems in less time and with 

less risk.

• The technology of wireless energy transfer via

microwave or laser beams has potential merit 

apart from SBSP application. Investing in the 

development of this technology may enable operations in remote and forward locations.

CONCLUDING REMARKS

Energy security is an issue that continues to become more acute as global populations grow and 

limited fossil fuel reserves shrink. The promises of 

space-based solar power for clean and unlimited energy for all humankind are certainly appealing. But 

the reality is that such systems always seem to be seen 

as just 10 years away by their advocates. While significant progress continues in the enabling technologies 

that will make SBSP systems economically viable and 

competitive power generators, there is no compelling evidence that such systems will provide the best 

energy solution. Considering the austerity of current 
39

federal budgets, the Army’s evolutionary approach to 

incorporating a diverse portfolio of renewable energy 

sources in distributed locations seems more prudent 

than placing significant amounts of resources in highrisk ventures such as SBSP systems. Perhaps in a decade or so, there will be technological breakthroughs 

that will fully support practical SBSP systems. But it 

is also possible that within that decade there may be 

breakthroughs such as fusion energy exploitation, 

which will make SBSP systems obsolete before they 

are even fielded. 

ENDNOTES

1. William Ledbetter, “An Energy Pioneer Looks Back: An Inspiring Conversation with Dr. Peter Glaser,” Ad Astra, Vol. 20, 

No. 1, Spring 2008, pp. 26-27.

2. Peter Glaser, “Method and Apparatus for Converting Solar 

Radiation to Electrical Power,” U.S. Patent No. 3,781,647, Alexandria, VA: U.S. Patent and Trademark Office, December 25, 1973.

3. Ibid., p. 1.

4. David J. Chow, “Exploring the Feasibility of Providing 

Electrical Power to Remote Bases Via Space-Based Solar Power 

Satellites,” Thesis for Master of Science in Systems Engineering 

Management, Monterey, CA: Naval Postgraduate School, June 

2013, pp. 19-26. This section of the thesis includes a detailed systems engineering functional analysis of an SBSP system, broken 

down by functional, physical, and allocated architectures.

5. National Aeronautics and Space Administration, “SpaceBased Solar Power Conversion and Delivery Systems Study, Vol. 

1: Executive Summary” report NASA-CR-150294, Princeton, NJ: 

Econ Incorporated, March 31, 1977. The objectives of the study 

were stated as (p. 2): 
40

With the above understanding in mind, the objectives of this 

study are to answer, sequentially, three questions:

1. Can it be done?

2. Should it be done?

3. How should it be done?

The first question addresses the basic technical and economic 

feasibility of the satellite solar power concept. Its purpose is to 

verify that the technology is at a point from which a development 

program may commence. The second question addresses the 

larger economic issue of whether a justification exists for undertaking the first phase of a satellite solar power development program. The last question addresses the level of effort and focus that 

results in an effective development program.

The full report had four additional volumes:

 Vol. II, Engineering Analysis of Orbital Systems (NASACR-150295);

Vol. III, Analysis of the Microwave Power Transmission 

System Interfaces and Power Beam Ionospheric Effects (NASACR-150296);

Vol. IV, Analysis of Photovoltaic Energy Conversion Systems (NASA-CR-150297);

Vol. V, Economic Analysis (NASA-CR-150298).

6. “Three Mile Island Generating Station” fact sheet, 

Chicago, IL: Exelon Corporation, available from www.

exeloncorp.com/assets/energy/powerplants/docs/TMI/fact_tmi.pdf, 

accessed September 12, 2014.

7. “Space-Based Solar Power Conversion and Delivery 

Systems Study, Vol. 1: Executive Summary” report, p. 2.

8. National Aeronautics and Space Administration, “SpaceBased Solar Power Conversion and Delivery Systems Study, Vol. 

V: Economic Analysis” report NASA-CR-150298, Princeton, NJ: 

Econ Incorporated, March 31, 1977, p. 4. 

9. Ibid., pp. 8-10.

10. Department of Energy, “The Final Proceedings of the Solar Power Satellite Program Review,” DoE/NASA Satellite Power 

System Concept Development and Evaluation Program, Washington, DC: DoE Office of Energy Research, July 1980. 
41

11. Ibid., p. 162.

12. Ibid., p. 143.

13. John C. Mankins, “A Fresh Look at Space Solar Power: 

New Architectures, Concepts and Technologies,” Paper IAF97-R.2.03, Turin, Italy: 48th International Astronautical Congress, October, 1997, p. 1, available from www.spacefuture.com/

pr/archive/a_fresh_look_at_space_solar_power_new_architectures_

concepts_and_technologies.shtml, accessed on September 15, 2014.

14. Ibid., p. 13.

15. National Research Council, Laying the Foundation for Space 

Solar Power: An Assessment of NASA’s Space Solar Power Investment 

Strategy, Washington, DC: National Academy Press, 2001, p. 1.

16. Ibid., p. 12-17. The report listed the NASA cost assumption 

of $800 per kilogram to reach GEO, a value that would require 

cost reductions greater than an order of magnitude. While this is 

not stated explicitly in the report, one can reasonably assume that 

the dollar values were based on its $2,000 value.

17. Ibid., p. 8. 

18. National Space Security Office, “Space-Based Solar Power 

as an Opportunity for Strategic Security: Phase 0 Architecture 

Feasibility Study,” Interim Assessment Release 0.1, Washington, 

DC: National Space Security Office, October 10, 2007, p. i.

19. Ibid., p. 5.

20. Ibid., p. 9.

21. Ibid., Appendix B-Demonstration Roadmap, pp. B-1 – B-5. 

22. Ibid., p. 31. 

23. Ibid., Appendix C-Business Case Analysis, pp. C-1 – C-2.

24. National Aeronautics and Space Administration “Advanced Space Transportation Program: Paving the Highway to 
42

Space,” fact sheet, Huntsville, AL: Marshall Space Flight Center, no date, available from www.nasa.gov/centers/marshall/news/

background/facts/astp.html, accessed September 16, 2014.

25. National Space Security Office, “Space-Based Solar Power 

as an Opportunity for Strategic Security: Phase 0 Architecture 

Feasibility Study,” p. 41-42.

26. W. Neil Johnson et al., “Space-based Solar Power: Possible 

Defense Applications and Opportunities for NRL Contributions,” 

Report NRL/FR/7650—09-10, 179, Washington, DC: Naval Research Laboratory, October 23, 2009, p. 1.

27. Ibid. The report’s details regarding feasibility were:

1.1.1 Concept Feasibility

The NRL SBSP Study Group concurs with the conclusions of the numerous studies of preceding decades that the 

SBSP concept is technically feasible but that there remain 

significant system risks in many areas.

The Group concurs that SBSP offers one of several possible solutions to the energy independence and dominance 

of our country and our military, and that those alternative 

solutions (including terrestrial solar, nuclear, and wind) 

must be an integral part of the solution.

Safe power densities for wireless energy transmission

generally restrict applications to large, relatively immobile, 

receiver sites.

Capital, launch, and maintenance costs remain significant concerns in the economics of fielding a practical SBSP 

system, an analysis of which is beyond the scope of this 

monograph.

28. Ibid., p. 2. For Relevant Research Areas, the report 

noted that: 

NRL has world class competencies in many of the engineering core areas necessary for SBSP risk reduction: thermal 

management, space structures, space robotic assembly, 

photovoltaics, RF (radio frequency) amplifier technology, 

energy storage and management, propulsion, and spacecraft and system engineering.
43

29. Ibid., p. 3.

30. John C. Mankins and Nobuyuki Kaya, eds., Space Solar 

Power, The First International Assessment of Space Solar Power: Opportunities, Issues, and Potential Pathways Forward, Paris, France: 

International Academy of Astronautics, August 2011, p. 183.

31. Ibid., p. xv. 

32. Ibid., p. 163.

33. Ibid., p. 159.

34. John C. Mankins, “SPS-ALPHA: The First Practical Solar 

Power Satellite via Arbitrary Large Phased Array (A 2011-2012 

NASA NIAC Phase 1 Project),” Santa Maria, CA: Artemis Innovation Management Solutions LLC., September 15, 2012, p. 17. 

35. Ibid., p. 47. 

36. Ibid., p. 106.

37. Ibid., p. 105. The author (John C. Mankins) of this report 

went on to write the book, The Case for Space Solar Power, Houston, 

TX: The Virginia Edition, Inc., 2014. Chapter 7 of the book, “LowCost Space Transportation,” provides an extensive and thorough 

review of the complex factors surrounding this challenge.

38. Mankins and Kaya, eds., Space Solar Power, The First International Assessment of Space Solar Power: Opportunities, Issues, and 

Potential Pathways Forward, p. 58. Table 4-1 of this report summarizes the SBSP key technology requirements from the IAA study 

in three categories: Class A-concept specific; Class B-generic space 

systems; and Class C-supporting infrastructures. 

39. Ibid., pp. 217-234 (Appendix E). This section of the report, “Technology Readiness and Risk Assessment,” provides a 

detailed assessment of critical technological challenges from the 

IAA study. It also describes the methodologies of Research and 

Development Degree of Difficulty (R&D3) as well as “Technology Readiness Levels” (TRLs) that were originally developed by 

NASA and now are widely used in defense acquisition as well. 

The nine TRLs’ progress observed (TRL-1) up to actual system 
44

proven in successful operation (TRL-9). The goal of many technology development programs is to reach TRL-6, which is “a 

representative model or prototype system tested in a relevant 

environment” (p. 218). 

40. Brian C. Busch, “Space-Based Solar Power System Architecture,” Thesis for Master of Science in Space Systems Operations, Monterey, CA: Naval Postgraduate School, December 2012, 

p. 49. In Table 18 of his thesis, Busch compares the theoretical, 

laboratory, and production efficiencies for five common photovoltaic materials. He also provides the time needed for them to 

degrade in performance by 15 percent.

41. Johnson et al., “Space-Based Solar Power: Possible Defense 

Applications and Opportunities for NRL Contributions,” p. 15. 

Table 4 of this report also compares the efficiencies for 11 different 

types of solar cells (p. 23). 

42. Chow, “Exploring the Feasibility of Providing Electrical 

Power to Remote Bases Via Space-Based Solar Power Satellites,” 

pp. 32-34.

43. Kyra Wiens, “Solar Power When It’s Raining: NRL Builds 

Space Satellite Module to Try,” NRL News Release, Washington, 

DC: NRL, March 12, 2014, available from www.nrl.navy.mil/media/

news-releases/2014/solar-power-when-its-raining-nrl-builds-spacesatellite-module-to-try, accessed on September 9, 2014. Other areas of SBSP research that NRL can support are included in Table 12 (p. 77) of W. Neil Johnson et al., “Space-based Solar Power: Possible Defense Applications and Opportunities for NRL 

Contributions.” 

44. Mankins, “SPS-ALPHA,” p. 19.

45. Busch, “Space-Based Solar Power System Architecture,” pp. 56-64. In this section of his thesis, Busch evaluates 

four existing commercial GEO satellite buses for potential SBSP 

application. 

46. Chow, “Exploring the Feasibility of Providing Electrical Power to Remote Bases Via Space-Based Solar Power 

Satellites,” p. 33.
45

47. National Research Council, Laying the Foundation for Space 

Solar Power, pp. 40-41.

48. Chow, “Exploring the Feasibility,” p. 34.

49. National Research Council, Laying the Foundation, 

pp. 42-43.

50. Busch, “Space-Based Solar Power System Architecture,” 

p. 74. Busch estimates that the construction of a GW-class satellite 

would require more than 120 heavy-lift space launches.

51. Department of Energy, “The Final Proceedings of the Solar Power Satellite Review,” p. 104.

52. Sun Xin et al., “Financial and Organizational Analysis for 

a Space Solar Power System: A Business Plan to Make Space Solar Power a Reality,” A Multicultural Team Project for Master of 

Business Administration in Aerospace Management, Toulouse, 

France: Toulouse Business School, May 18, 2009, p. 60. The study 

assumes a market price for electricity of 0.08 Euros, which converts to slightly more than 10 cents (U.S.) An informal search of 

numerous electrical utility rate comparison websites in Pennsylvania showed rates to be within about 10 percent of this value. 

53. Samuel H. Williamson, “Seven Ways to Compute the 

Relative Value of a U.S. Dollar Amount,” available from www.

measuringworth.com/uscompare/relativevalue.php, accessed on September 17, 2014. This website included a calculator that provides 

a range of relative values of the U.S. dollar between two selected 

years. The range is set by the lowest and highest values that result 

from seven different methods of comparison. For Table 1, the lowest value of each range was used to give the lowest cost for comparison. The calculated ranges used in calculating Table 1 values 

were: the 1977 to 2013 dollar range was 3.04 to 8.04; the 1997 to 

2013 dollar range was 1.37 to 1.95; the 2007 to 2013 dollar range 

was 1.10 to 1.16; the 2009 to 2013 dollar range was 1.04 to 1.06; 

and the 2012 to 2013 dollar range was 1.00 to 1.04. The B in Table 

1 represents billions.
46

54. Department of Energy, “The Final Proceedings of the Solar Power Satellite Review,” p. 104; and National Aeronautics and 

Space Administration, “Space-Based Solar Power Conversion 

and Delivery Systems Study, Volume V: Economic Analysis,” p. 

4. The $89.0 billion for satellite development was derived by subtracting the total cost ($102.5 billion) from the embedded first unit 

cost ($13.5 billion). 

55. Mankins, “A Fresh Look at Space Solar Power: New Architectures, Concepts and Technologies,” pp. 8 and 11. 

56. National Research Council, Laying the Foundation for Space 

Solar Power, p. 17.

57. National Space Security Office, “Space-Based Solar Power 

as an Opportunity for Strategic Security: Phase 0 Architecture 

Feasibility Study,” p. B-1.

58. Mankins, “SPS-ALPHA: The First Practical Solar Power 

Satellite via Arbitrary Large Phased Array (A 2011-2012 NASA 

NIAC Phase 1 Project),” pp. 104-106.

59. Chow, “Exploring the Feasibility of Providing Electrical Power to Remote Bases Via Space-Based Solar Power 

Satellites,” p. 47.

60. Xin et al., “Financial and Organizational Analysis for a 

Space Solar Power System,” p. 60. 

61. Walmart financial information is from “Fortune 500 2014,” 

available from fortune.com/fortune500/, accessed on September 

20, 2014. NASA and DoE budgets are from “The President’s Budget for Fiscal Year 2015,” available from www.whitehouse.gov/omb/

budget/Overview, accessed on September 20, 2014.

62. Xin et al., “Financial and Organizational Analysis for a 

Space Solar Power System,” pp. 60-65. 

63. Ibid., p. 108. The M and B in Table 2 represents millions 

and billions respectively and O&M represents operations and 

maintenance.
47

64. Energy Information Administration, Updated Capital Cost 

Estimates for Utility Scale Electricity Generating Plants, Washington, 

DC: Department of Energy, April 2013, p. 1.

65. John Miller, “What are the Capacity Factor Impacts on 

New Installed Renewable Power Generation Capacities?” available from theenergycollective.com/jemillerep/450556/what-are-capacity-factor-impacts-new-installed-renewable-power-generation-capaciti, 

accessed September 21, 2014. This blog article notes that “relatively new EIA [Energy Information Administration] data report 

shows that Wind and Solar PV [photovoltaic] capacity factors 

have been well below the projected state-of-art level” and recommended a value of 20 percent vice the EIA estimate of 25 percent. 

In keeping with the analysis methodology of this monograph, the 

author selected the 20-percent value in order to give the best case 

for SBSP systems.

66. Ibid., p. 6. The relevant photovoltaic power plant estimates 

used from Table 1 of this source were: 

Note that the term “overnight capital costs” refers to costs of the 

project if no interest is incurred during construction.

67. Mankins and Kaya, eds., Space Solar Power, The First International Assessment of Space Solar Power: Opportunities, Issues, and 

Potential Pathways Forward, pp. 72-73. Chap. 5, “SPS Policy and 

Other Considerations,” addresses several regulatory and policyrelated issues for the international community.

68. National Research Council, Laying the Foundation for Space 

Solar Power, p. 56. 

69. Nicholas L. Johnson. “A New Look at the GEO and NearGEO Regimes: Operations, Disposals, and Debris,” IAC-11.A6.2.7 

in 62nd International Astronautical Congress 2011 (IAC 2011) Proceedings, Vol. 1 of 12, Cape Town, South Africa, October 3-7 2011, 

pp. 1932-1938. 

70. Ibid., p. 1938. 

20 MW plant: $4,183 $/KW (capital) $27.75 $/KW-yr (O&M)

150 MW plant: $3,873 $/KW (capital) $24.69 $/KW-yr (O&M)
48

70a. National Research Council, Laying the Foundation for Space 

Solar Power: An Assessment of NASA’s Space Solar Power Investment 

Strategy, pp. 25-26.

71. Nobuyuki Kaya, “New Basic Plans for Space Policy,” The 

Proceedings of the Panel Discussions on the Space Solar Power Systems, 

Tsukuba, Japan: International Symposium on Space Technology 

and Science, July 10, 2009, pp. 33-42. 

72. Susumi Sasaki, “How Japan Plans to Build an Orbital Solar Farm,” IEEE Spectrum online, April 24, 2014, p. 1, available 

from spectrum.ieee.org/green-tech/solar/how-japan-plans-to-build-anorbital-solar-farm, accessed on September 3, 2014. 

73. Ibid., p. 4. To accomplish its technology roadmap, JAXA 

established the following priorities: 

To complete and operate an electricity system based on 

such satellites, we would have to demonstrate mastery of 

six different disciplines: wireless power transmission, space 

transportation, construction of large structures in orbit, 

satellite attitude and orbit control, power generation, and 

power management. Of those six challenges, it is the wireless power transmission that remains the most daunting. So 

that is where JAXA has focused its research.

74. European Space Agency, “ESA Work on Solar Power 

from Space: Concluded and Ongoing Activities,” Noordwijk, The 

Netherlands: ESA Advanced Concepts Team, January 2008, p. 2.

75. Leopold Summerer, “Solar Power from Space—European Strategy in the Light of Global Sustainable Development: 

Programme Plan,” Noordwijk, The Netherlands: European Space 

Agency, July 8, 2003. 

76. Leopold Summerer, “Solar Power from Space: Status and 

Perspectives,” in The Proceedings of the Panel Discussions on the 

Space Solar Power Systems, Tsukuba, Japan: International Symposium on Space Technology and Science, July 10, 2009, p. 24. 

77. Arnulf Jäger-Waldau, Research, Solar Cell Production and 

Market Implementation of Photovoltaics, Ispra, Italy: European Commission Joint Research Centre, October 2012, p. 36.
49

78. Ibid., p. 38. 

79. Peter Garretson, “Solar Power in Space?” Strategic Studies 

Quarterly, Vol. 6, No. 1, Spring 2012, pp. 97-123. 

80. Robert M. Gates, Secretary of Defense, and James R. Clapper, Director of National Intelligence, National Security Space Strategy: Unclassified Summary, Washington, DC: U.S. Government 

Printing Office, January 2011, p. 1. 

81. “Satellite Box Score as of 2 July 2014,” NASA Orbital Debris 

Quarterly News, Vol. 18, No. 3, July 2014, p. 8. 

82. Gates and Clapper, p. 1.

83. U.S. Government Accountability Office, “Defense Acquisitions: Assessments of Selected Weapon Programs,” Report 

GAO-14-340SP, Washington, DC: U.S. Government Printing Office, March 31, 2014, pp. 18, 143.

84. Headquarters, Department of the Army, “Stand To! Energy Initiatives Task Force,” Washington, DC: HQ, Department of 

the Army, September 20, 2011, p. 1, available from www.army.mil/

standto/archive/issue.php?issue=2011-09-20, accessed on September 

15, 2014.

85. Ibid., p. 1. 

86. John Lushetsky, “Renewables in the Federal Government: 

EITF Renewable Energy Overview,” presentation at the 2013 

World Energy Engineering Congress, Washington, DC, September 27, 2013. 

87. “Fort Detrick, Maryland 18.6 MW Solar PV Project Overview,” fact sheet, Arlington, VA: Army Energy Initiatives Task 

Force, November 2013, available from www.asaie.army.mil/

Public/ES/eitf/docs/FactSheet_FtDetrick.pdf, accessed on September 

12, 2014. 
50

88. “Georgia 3x30: Bringing Large-scale Renewable Energy to 

Forts Stewart, Gordon, and Benning,” fact sheet, Arlington, VA: 

Army Energy Initiatives Task Force, May 2014, available from 

www.asaie.army.mil/Public/ES/eitf/docs/19May2014Ga3x30FactSheet.

pdf, accessed on September 12, 2014.

89. “Fort Huachuca Renewable Energy Project,” fact sheet, 

Arlington, VA: Army Energy Initiatives Task Force, March 2014, 

available from: www.asaie.army.mil/Public/ES/eitf/docs/FactSheet_

FtHuachuca.pdf, accessed on September 12, 2014.

90. “Fort Irwin, California 15 MW Solar PV Project Overview,” fact sheet, Arlington, VA: Army Energy Initiatives Task 

Force, June 22, 2013, available Fort Irwin, CA, 15 MW Solar PV 

Project Overview,” fact sheet, Arlington, VA: Army Energy Initiatives Task Force, June 22, 2013, available from www.asaie.army.

mil/Public/ES/eitf/docs/SolarPV-FortIrwinCalifornia.pdf, accessed on 

September 12, 2014.

91. “Redstone Arsenal Solar Project Task Order Under MATOC,” fact sheet, Arlington, VA: Army Energy Initiatives Task 

Force, July 2014, available from www.asaie.army.mil/Public/ES/eitf/

docs/RedstoneArsenalFactSheet.pdf, accessed on September 12, 2014.

92. “Fort Stewart, Georgia Solar PV Lease,” fact sheet, Arlington, VA: Army Energy Initiatives Task Force, January 2014, 

available from www.asaie.army.mil/Public/ES/eitf/docs/FactSheet_

FtStewart_01-2014.pdf, accessed on September 12, 2014.

93. Using an average capacity value of 20 percent for Table 3 

values is consistent with the assumptions used to generate Table 

2 values. 

94. Calculations for these numbers used an average capacity 

value of 20 percent for terrestrial photovoltaic (PV) systems. Thus, 

a 5-GW land PV system is needed to provide the same output as 

a 1-GW SBSP system operating continuously. Applying the direct 

ratio scaling from 171.6-MW to 5-GW to 7.6 square KM yields 221 

square KM for the terrestrial system. The area for the rectenna depicted in Figure 2 is simply multiplying the semi-major (6.5-km) 

and semi-minor (5.0-km) axes values together with pi.
51

95. Xin et al., “Financial and Organizational Analysis for a 

Space Solar Power System,” p. 70. This report bases its FOB usage estimates on the details of FOB operations explored by the 

Air Force Research Laboratory. The report also describes a 1-MW 

Mobile Space-to-Ground Solar Power Station (MSGSPS) system 

that is expeditionary in design, using C-130 airlift transportation 

and standard cargo trucks.

96. A. M. Rubenchik et al., “Solar Power Beaming: From Space 

to Earth,” report LLNL-TR-412782, Livermore, CA: Lawrence 

Livermore National Laboratory, April 2009, pp. 1, 11. 

97. Busch, p. 22.

98. Joint Publication 3-14, Space Operations, Washington, DC: 

Joint Chiefs of Staff, May 29, 2013, p. G-4. The Orbit Types graphic 

is from Figure G-1. Also see Busch, pp. 19-44. Chap. 3 of this thesis 

provides the detailed calculations for the satellite view times as 

shown in Figure 6. 

99. Johnson et al., “Space-based Solar Power,” pp. 5-6. 

53

APPENDIX 1

ASSESSMENT OF SPACE-BASED 

SOLAR POWER APPLICATIONS

FOR MILITARY OPERATIONS SCENARIOS*

Military 

Operation 

Scenario

Rationale 

for SBSP

Feasibility

Notes

Earliest 

operational 

capability

Rough 

magnitude Technical Economic cost

Forward Operating 

Base Power

Reduce fuel 

convoys Possible Possible Probably best SBSP defense app >5 years $10B+

Provide power to a 

ship or other large 

seaborne platform

Refuel from 

space Possible Possible

Almost certainly 

requires lasers 

and high power 

densities

> 5 years $10B+

Bistatic radar illuminationImprove 

imaging Possible Possible Feasible but expensive > 5 years $10B+

Provide power to a 

remote location for 

synthfuel production

Reduce 

infrastructurePossible Possible

Requires 

transportation 

architecture 

that consumes 

synthfuel

> 5 years $10B+

Power to Individual 

End Users

Reduce 

battery 

mass

Unlikely Unlikely

Power inefficient, 

severe beam 

control, and safety 

challenges

> 10 years ?

Power for Distributed Sensor 

Networks

Cover large 

area Possible Possible Power inefficient > 5 years $10B+

Spaced solar power to non-terrestrial targets

Satellite to satellite 

power transmission

Fractionate 

spacecraft Possible Possible

Significant technical issues, questionable utility

> 2 years $50M+

Space to unmanned 

aerial vehicle (UAV) 

for dwell extension

Prolong 

dwell time Possible Possible*

*if used in conjunction with FOB 

power

> 5 years $10B+

Terrestrial Wireless Power Beaming Applications Apart from SBSP

Ship to shore power 

beaming

Increase 

flexibility Possible Possible

Attractive defense 

app, requires 

more study

> 1 years $10M+

Ground to UAV for 

dwell extension

Prolong 

dwell times Demonstrated Possible

May be unnecessary in light of 

recent UAV tech 

advances

> 1 years $10M+

*Source: W. Neil Johnson et al., “Space-based Solar Power: Possible Defense 

Applications and Opportunities for NRL Contributions,” Report NRL/

FR/7650—09-10, 179, Washington, DC: Naval Research Laboratory, October 

23, 2009, p. 3 (Table 1, Investigation Summary).
U.S. ARMY WAR COLLEGE

Major General William E. Rapp

Commandant

*****

STRATEGIC STUDIES INSTITUTE

and

U.S. ARMY WAR COLLEGE PRESS

Director

Professor Douglas C. Lovelace, Jr.

Director of Research

Dr. Steven K. Metz

Author

Mr. Jeffrey L. Caton

Editor for Production

Dr. James G. Pierce

Publications Assistant

Ms. Rita A. Rummel

*****

Composition

Mrs. Jennifer E. Nevil