- - - 

NASA Contractor Report 3349 

Satellite Power System 

and Disposal Alternativ 

Salvage 

-es 

CONTRACT NASs-33783 

NOVEMBER 1980 

TECH LIBRARY KAFB, NM 

Chapter Page 

List of Figures V 

TABLE OF CONTENTS 

IInlllllllllll~llllllll

0062d3b 

List of Tables vi. 

1. Introduction 1 

1.1 Background 2 

1.2 Approach 4 

1.3 Results 9 

1.4 Conclusions and Recommendations 13 

1.5 Backup Documentation 15 

2. A Post-2000 Mission Model 16 

2.1 The Period 2000 to 2030 22 

2.2 The Post-2030 Time Period 26 

3. 

4. 

SPS Demonstration Satellite Salvage Alternatives 

3.1 Growth to Full-Scale Satellite 

3.2 Demonstration Satellite Use as a Power Supply for Non-SPS 

Space Activities 

3.3 Power Supply for a Laser Orbit-to-Orbit Transportation System 

3.4 Source of Space-Based Materials 

Full-Scale Satellite Salvage Alternatives 

28 

33 

37 

46 

49 

50 

4.1 Salvage for SPS Reuse 50 

4.2 Power Supply for Non-SPS Space Activities 52 

4.3 Power Supply for a Laser Orbit-to-Orbit Transportation Systems 53 

4.4 Power Supply for Laser-Propelled Aircraft 54 

4.5 Asteroid Capture and Mining 57 

4.6 Source of Space-Based Materials 59 

4.7 Miscellaneous Salvage Uses 60 

4.8 Continued Use 61 

5. SPS Salvage Value 64 

5.1 SPS Demonstration Satellite Salvage‘ Value 64 

5.2 Full-Scale SPS Satellite Salvage Value 66 

5.3 Programmatic Implications 68 

. . . 111 
TABLE OF CONTENTS 

(Continued) 

Chapter Page 

6. SPS Disposal 71 

6.1 Disposal Alternatives 71 

6.2 Disposal Costs 78 

Appendix A Supporting Data for Value of the Demonstration Satellite 

Used as a Power Source for Other Activities 80 

iv 
LIST OF FIGURES 

Figure 

1.1 

1.2 

2.1 

2.2 

2.3 

3.1 

3.2 

3.3 

3.4 

3.5 

3.6 

3.7 

3.8 

3.9 

4.1 

4.2 

5.1 

5.2 

6.1 

6.2 

6.3 

Reference Satellite Configuration 

Salvageable SPS Mass and Generation Capacity 

Geostationary Satellites--To Date and Planned 

Potential Space Activity Levels, 1980-2060 

Historical and Projected Growth of Spacecraft Power and Lifetime 

SPS Demonstration Satellite in Final Phases of Construction 

Full-Scale Operational SPS Satellite Configuration 

Salvage Value-- Growth to Full-Scale Satellite 

Present Value of Demonstration Satellite When Used as an Initial 

Element in a Full-Scale Satellite 

Supply & Demand for Power from Demonstration SPS Satellite 

Salvage Value-- SPS Demonstration Satellite Used as a Source of 

Power and Other Subsystems for Other Activities 

Salvage Value of the SPS Demonstration Satellite When Used as a 

Source of Power for Other Activities 

Salvage Value of SPS Demonstration Satellite When Used as a 

Source of Power and Other Subsystems for Other Activities 

LEO to CEO Traffic Growth 

Continued Use SPS Salvage Value 

The Decision to Decommission an SPS Satellite 

Summary of Demonstration and Full-Scale Satellite Salvage Applications 

Programmatic Implication of Demonstration Satellite Salvage Value 

Lagrangian Points in the Earth-Moon System 

EOTV Configuration 

Alternative Trajectory Modes 

Page 

2 

5 

19 

21 

25 

29 

30 

34 

38 

39 

40 

45 

45 

48 

62 

63 

65 

69 

73 

76 

77 

V 

I 
LIST OF TABLES 

Table 

1.1 

1.2 

1.3 

2.1 

3.1 

3.2 

Reference Satellite Characteristics 

SPS Satellite and Rectenna Salvage Value 

Disposal Options and Costs 

Traffic to Support CEO Platforms 

Demonstration Satellite Cost Structure 

Mass Properties of Full-Scale and Demonstration SPS 

Satellites 

4.1 Current Oceanic Air Traffic 

4.2 Characteristics of Amor and Apollo Asteriods 

4.3 Value of SPS Satellite Materials--GaAs, CR=2 

Page 

3 

10 

13 

26 

31 

32 

55 

58 

60 

vi 
1. INTRODUCTION 

SPS system cost and trade studies conducted to date have, by and large, 

assumed a 30-year satellite life with zero net salvage value at the end of that 

time. Many factors make this assumption inappropriate: 

1. The SPS satellite represents a very large source of power in geosynchronous orbit that might be put to many uses, such as: 

0 Power for other space-based platforms, satellites, habitats, manuf acturing facilities, bases, etc. 

0 Power for laser transportation systems including geocentric 

space, earth escape and laser-powered aircraft 

0 Power for a large, low-thrust space transportation system for 

missions such as asteriod recovery 

0 Power for space-based science such as particle physics. 

2. The SPS satellite represents a large supply of subsystems and components for use in other space activities such as: 

0 Spares and materials for other SPS satellites 

0 Solar arrays and other components for non-SPS satellites. 

3. The SPS satellite represents a fairly large source of raw materials 

located in geosynchronous orbit that might be recovered and put to use 

either in space or returned to earth for reuse. 

The first SPS satellite will approach the end of its useful life around the year 2030; 

some 30 years sooner, the SPS demonstration satellite will have served its initial 

purpose. The demonstration satellite represents a somewhat similar, albeit 

considerably smaller, resource. 

To the extent to which there develops a demand for energy, SPS-like 

subsystems and raw materials in space, one can expect that SPS will derive some 

salvage value. If, on the other hand, no such demand develops, the SPS satellite will 

have to be removed from geosynchronous orbit (CEO), either for storage and 
2 

possible later salvage use or for permanent disposal. In this case it is important to 

have estimates of the cost of SPS satellite disposal. 

The objectives of this study are to find potential salvage uses for. both the 

SPS demonstration and full-scale satellites, to determine the satellite salvage 

values for each potential use, to prioritize these uses in order to determine likely 

salvage value per satellite as a fraction of satellite capital cost and to determine 

the cost of disposal for unsalvaged satellites or portions thereof. 

1.1 Background 

The salvage uses and values and disposal costs estimated in this study are 

based on the Rockwell International SPS satellite configuration and development 

program. The basic satellite configuration is shown in Figure 1.1 and its major 

pnysical characteristics are provided in Table 1.1. The satellite uses gallium 

aluminum arsenide solar cells with a concentration ratio of 2 and a graphite 

composite structure. 

SOURCE : SATELLITE 

POWER SYSTEMS (SPS) 

CONCEPT DEFINITION’ 

STUDY, EXECUTIVE 

SUMM4RY, SSD 79-0010- 

1, ROCKWELL INTERNATIONAL, DOWNEY, CA, 

MARCH 1979. 

FIGURE 1.1 REFERENCE SATELLITE CONFIGURATION 
TABLE 1.1 REFERENCE SATELLITE CtWMCTERISTlCS* 

.;==----- =_ 

YS GENERATION CAPABILITY (UTILITY 5 GU 

INTERFACE) 

OVER&L DIMNSIONS (Kl’l) 

SATELLITE MS (KC) 

COYER CONVERSION-PHOTOVOLTAIC 

STRUCTIRE MATERIAL 

CONSTRUCTION LOCATION 

TRANSPORTATION 

l EARTH-TO-LEO -CARGO 

(PAYLOAD) 

-PERSONNEL 

(NUMBER) 

l LEO-TO-GE0 -CARGO 

-PERSONNEL 

(NUPIBER) 

5.3 x 10.4 

34 x 105 

hAlAs (CR = 2) 

GRAPHITE COMPOSITE (GFRTP) 

6EO 

VERTICAL TAKEOFF. YIN6EO 2-STAGE 

(424,000 KG) 

ClDOIFIED SHUTTLE 

(75) 

DEDICATED ELECT. OTV 

2-STAGE LOX/LH2 

(75) 

MICROWAVE POKER TRANSMISSION 

0 n0. OF ANTENNAS 1 

l AnTENNA POINTING/CONTROL CONTROL WENT GYROS (CMGs) 

l DC-RF CONVERTER KLYSTRON 

l FRE’JJENCY (GH) 2.45 

l RECTENNA DI=NSIONS (KM) 10 x 13 

l RECTEWA POWER DENSITY 

wcl?‘) 

-CENTER 23 

-EDGE 1 

l SDURCE : SATELLITE POWER SYSTEMS (SPS) CONCEPT DEFINITION STUDY, 

EXECUTIVE SIBWRY. SSD 79-0010-l. RDCKYELL INTERNATIONAL. MUNEY. CA. WCH 1979. 

The development and implementation program for this satellite calls for 

deployment of a geosynchronous demonstration satellite, with a power generation 

capability of 335 MW at beginning of life, early in the year 1999. Shortly 

thereafter, the demonstration satellite is grown into a full-scale satellite with a 

generation capability (in space) of 9.53 CW (8.92 GW power into the microwave 

antenna). The first full-scale SPS satellite becomes operational late in the year 

2000. Following the first full-scale SPS, the reference program calls for bringing 

two 5 CW systems on line each year, beginning in the year 2001, until a total of 60 

systems, 300 GW capacity, are installed. 
4 

Using the above program plan, the demonstration satellite becomes available 

for salvage early in the year 2000 and full-scale SPS satellites become available for 

salvage at the rate of two per year beginning late in the year 2030. Concurrent 

with the full-scale satellites, the rectenna also becomes available for salvage. It is 

possible that the rectenna will be used for a subsequent SPS if the program 

continues. If this is the case, some amount of refurbishment may be necessary 

and/or desirable, thus allowing evolutionary changes in the satellite portion of the 

system, such as beam power density, beam shape and size, frequency and 

polarization. In any event, rectenna reuse may be considered to be a salvage use. 

Figure 1.2 shows the amount of SPS materials which will have become available for 

salvage as a function of time. 

The utilization of geosynchronous orbit in the post-2000 time period is likely 

to be quite intense. Thus it is likely that any structures or satellites that are 

placed in this orbit will have to be removed upon completion of their useful life. 

Accordingly, any unsalvaged SPS-related structures, facilities or satellites will 

have to be disposed of at the end of their useful life. 

1.2 Approach 

It is clear from Figure 1.2 that all salvage and disposal activities will occur in 

the post-2000 time period. Salvage or disposal of the demonstration satellite will 

occur somewhere in the 2000 to 2010 time period; salvage or disposal of full-scale 

satellites will begin sometime after 2030 and continue at least through 2060. In 

order to make any estimates of salvage uses and salvage values, it is necessary to 

place the potential salvage activities into the context of a space program. Thus it 

is necessary first to establish a mission model for the period 2000 to 2060 as a basis 

for analysis. Obviously any such mission model will suffer from major uncertainties and, in the end, one can identify only certain long-term trends without 

becoming specific about particular missions. 
1.0 

0.5 

0 

300 

200 

MISC. 

K+P$!! 

ui a s 

ALUMINUM 

SAPPHIRE 

COPPER 

STAINLESS 

STEEL 

GFRTP 

2000 2030 2040 2050 

CALENDAR YEAR 

(a) CUMULATIVE SALVAGEABLE MASS 

2060 

2000 2030 2040 2050 2060 

CALENDAR YEAR 

(b) CUMULATIVE SALVAGEABLE GENERATION CAPACITY 

FIGURE 1,.2 SALVAGEABLE SPS MASS AND GENERATION CAPACITY 
6 

The generic trends which one can identify today that are likely to carry over 

into the 21st century include mainly an t’industrialization” of Space; that is, a 

gradual transition from government-funded activities primarily of a research 

nature to activities promoted and conducted in the private sector because they are 

profitable. It is likely that these activities will be encouraged by significant 

reductions in the cost of space-based activities resulting from a transition to the 

Space Shuttle and more advanced space transportation systems, and by the 

introduction and proliferation of multipurpose platforms. 

Much of the activity in space in the post-2000 time period will take place in 

geosynchronous orbit. This activity is likely to generate a considerable amount of 

low earth orbit (LEO) to GE0 traffic, independent of SPS. There is also likely to 

be considerable other geocentric traffic, however, including LEO to GEO, GE0 to 

GE0 and lunar traffic, as well as earth escape traffic. Within the context of these 

space activities, potential salvage uses for both the SPS demonstration satellite 

and full-scale SPS satellites were identified and evaluated. 

It is not clear today that the SPS demonstration will be a success; that is, 

that upon completion of the demonstration satellite project, it will be found 

desirable to proceed with construction of full-scale SPS satellites as planned. (If it 

were known today that the demonstration would be successful, it would be 

unnecessary.) Thus salvage uses of the demonstration satellite need to recognize 

that there may or may not be a continuing SPS program. 

On the other hand, salvage of full-scale SPS satellites will occur only if there 

is an SPS program and, consequently, the salvage uses for full-scale SPS satellites 

are appropriately identified in the context of a space program which includes SPS. 

Such a program clearly requires a space transportation system that can inexpensively transport large amounts of materials to geocentric space, and it includes 
7 

capabilities in large space structures, space-based construction, manned LEO and 

CEO facilities, and so on. These capabilities infer such space-based activities as 

space manufacturing, the utilization of large applications platforms, lunar exploration and exploitation, and physics and astronomy. 

The above space-based activities lead to identification of the following 

potential salvage uses: 

Demonstration Satellite 

0 Growth into full-scale SPS satellite (Rockwell International reference 

program plan, applicable only if the demonstration is successful) 

0 Use .as a source of power for other space activities such as CEO 

platforms, a manufacturing base or an electric orbit transfer vehicle 

0 Use as a power supply for a laser space transportation system 

0 Use as a source of raw material. 

Full-Scale SPS Satellites 

0 Use as spares and materials for other SPS satellites 

0 Use as a power supply and platform for other space activities such as 

platforms, a manufacturing base, a lunar base or space habitats 

0 Use as. a power supply for laser transportation systems including 

geocentric space, especially LEO to CEO, earth escape and aircraft on 

oceanic routes 

0 Use as a power supply to recover Amor and Apollo asteriods 

0 Use as a power supply for a high-energy, high-vacuum physics laboratory in space. 

Next, the salvage value of the SPS satellites was estimated for most of the 

above potential uses. In all cases the salvage value is taken to be the present 

value of the cost savings afforded by the salvage use referenced to the initial 

operation date of the salvaged article. The discount rate used throughout this 

study is a real (i.e., inflationary effects removed) rate of 4 percent. Thus, the 

salvage values presented represent the effective amount by which the capital cost 
8 

of the satellite is reduced because it will provide a positive net salvage value. The 

present value of SPS revenue requirements, reflected in the SPS charge’ rates, may 

accordingly be reduced by this amount. For example, if it is found that the salvage 

value of an SPS satellite is equal to ten percent of the capital cost of the satellite, 

then the annual capital carrying charge for the satellite, for purposes of comparison to alternative systems, may be reduced by ten percent. 

Any SPS satellites or portions thereof which are not salvaged will, in all 

likelihood, have to be removed from geosynchronous orbit. An objective of this 

study is to estimate SPS satellite disposal costs. To do this a number of disposal 

alternatives were identified, the velocity requirements for each were estimated 

and then the costs of each were determined. SPS disposal costs include four 

major cost categories: cost of propellant, cost of transporting the propellant to 

CEO, cost of modifying the SPS satellite as necessary (mainly installation of 

thrusters, tankage and controls) and the cost of mission operations. cost 

estimates provided are based on the assumption that the satellite is disposed of 

intact. 

Wherever possible cost estimates used in this study were derived from the 

SPS Concept Definition Study performed by Rockwell International,* and are in 

1977 dollars, consistent with this report. Thus while these cost estimates contain 

considerable uncertainty, the variation in estimates of salvage value and disposal 

costs are likely to approximate the variations in satellite captial costs. Hence the 

estimates provided can be taken to be relatively firm when viewed in comparison 

to the capital cost estimates. 

7 

Satellite Power Systems (SPS) Concept Definition Study, System Engineering, 

Part 2 (Cost and Programmatics, Rockwell International Report No. SSD 79- 

0010-2-2, March 1979. 
9 

1.3 Results 

Discussion of the results is appropriately divided into four parts: salvage 

value for potential salvage uses of the demonstration satellite, salvage -value for 

potential salvage uses of full-scale SPS satellites, salvage value of rectennae and 

disposal costs for the demonstration and full-scale satellites. The major study 

results are summarized in Table 1.2. 

Two principal salvage uses for the demonstration satellite are apparent: 

growth to a full-scale satellite and use as a power supply for a laser space 

transportation system. Obviously, the former use applies only if the demonstration 

program is a success; that is, if it is found desirable to continue the SPS program 

beyond the demonstration phase. If this salvage use is implemented, the salvage 

value of the demonstration satellite is about 80 percent of the on-orbit cost of the 

salvageable hardware. Since almost all of the demonstration satellite is salvageable (except perhaps the ion thrusters and associated systems used to transport it 

from LEO to GEO), one can take the salvage value to be essentially 80 percent of 

the on-orbit cost of the demonstration satellite. The reason that the salvage value 

of the demonstration satellite is not 100 percent of its cost is because of the time 

value of money (discounting) and the time delay between investment in the 

demonstration satellite and start of construction of the full-scale satellite. 

The second principal salvage use of the demonstration satellite, use as a 

power source for a laser space transportation system, is a viable salvage use 

whether the demonstration program is a success or not. The salvage value for this 

use derives mainly from cost savings in the cost of transporting chemical 

propellants from earth to LEO for use in LEO to CEO transportation of personnel 

and logistics. The considerably higher specific impulse of a laser rocket permits 

about a 70 percent reduction in the mass of propellant that must be transported to 
POTENTIAL DEMAND 

POTENTIAL SALVAGE USE SALVAGE VALUE FOR SALVAGE USE REMARKS 

DEMMSTRATDM SATELLITE 

l GROUTH TO FULL-SCALE 

l POUER SUPPLY FOR OTHER SPACE 

ACTIVITIES 

80% OF ON-ORBIT COST ENTIRE DEMINSTRATION VALID USE ONLY IF DEMONSTRATIDR 

OF SALVAGEABLE HARDWARE SATELLITE IS SUCCESSFUL 

SMALL LIMITED TO MALL SALVAGE SPREAD OVER SEVERAL 

FRACTION OF AVAILABLE YEARS 

POUER 

a POUER SUPPLY Fa\ LASER SPACE 

TRANSFORTATIOR SYSTEM 

11.7 BILLION + DOES MIT RAKE USE OF BENEFIT OF SALVAGE USE LIKELY 

TRAJISHITTING ANTENNA TO BE CONSIDERABLY HIGHER IF 

DEWINSTRATION IS SUCCESSFUL 

l SEHRtCE OF RAY ClATERIAL 

FULL-SCALE SPS SATELLITES 

VERY SHALL VERY LIMITED MIT A LIKELY SALVAGE USE 

0 SPARES AND MATERIALS FOR 

OTHER SPS SATELLITES 

VERY SRUL SUBSTANTIAL DENAND MIT CLEAR THAT ANY SPS 

FOR KLYSTRONS--LIMITED COMPONENTS UILL BE REUSABLE 

DEClAND FOR OTHER AFTER SERVICE 

COMPONENTS 

l POUER SUPPLY FOR OTHER 

SPACE ACTIVITIES 

0 WUER SUPPLY FOR LASER' 

TRAnSPCRTATION SYSTEMS 

0 FDUER SUPPLY TO RECOVER 

AMR AND APOLLO ASTEROIDS 

VERY SMALL 

$1-3 BILLION 

f.5-3 BILLION 

DEMND FOR POUER IN LIKELY THAT SME REUSE OF 

SPACE LIKELY TO BE ONLY SPS SDLAR ARRAYS WULD DCCUR 

A VERY WALL FRACTION OF 

AVAILABLE POWER 

TOTAL DEMAND COULD VERY PROMISING SALVAGE USE 

REACH OVER 20 SATELLITES 

DEPENDS ON LEVEL OF IOT SUFFICIENT KIIOWLEDCE TO 

SPACE ACTIVITY OETERRINE VALUE ACCURATELY-- 

COULD USE Iv\NY SATELLITES 

0 POWER SUPPLY FIX HIGH-ENERGY, 

HIGH-VACUUI PHYSICS LAB 

RECTENNAE 

IOT DETERMINED POSSIBLY WRE THAN ONE 

SATELLITE 

0 SALVAGE AND RESALE OF LAND $30 MILLION ALL RECTENNA SITES SALVAGE VALUE OF 'STEEL AND 

ALUMINUM OFFSET BY REII)VAL 

COST FOR CONCRETE 

0 REUSE UITH NEW SATELLITE UP TD 30% OF RECTENRA 

COST 

ALL RECTEWA SITES SALVAGE VALUE DEPENDS MI 

REFURBISHIIENT COST 

4 

TABLE 1.2 SPS SATELLITE AND RECTENNA SALVAGE VALUE 
11 

LEO compared to chemical rockets. The availability of a multi-lOO.MW power 

supply enables laser rocket transfer times from LEO to CEO to be quite 

comparable to chemical rocket transfer times. 

The value of a laser space transportation system is clearly dependent upon 

the amount of LEO to GE0 and other geocentric space traffic. If the SPS program 

does not proceed beyond the demonstration phase, the bulk of the geocentric 

traffic will be in support of geosynchronous platforms, providing the salvage value 

shown in Table 1.2. If the SPS program continues into an operational phase, 

however, the value of a laser space transportation system is substantially greater. 

Particularly with a continuing SPS program, the laser space transportation system 

appears so attractive that it is likely that it will be developed and used independent 

of what.is done with the demonstration satellite. 

Many potential salvage uses of substantial value exist for full-scale SPS 

satellites. Their value, however, is very uncertain due to the fact that these uses 

occur 50 to 80 years in the future. The uses which appear to be most attractive 

include laser transportation systems, both space-to-space and for aircraft on 

oceanic routes, as a power supply to recover Amor and Apollo asteroids and, 

although not quantitatively evaluated, as a power supply for a high-energy, 

high-vacuum physics laboratory in space. It is conceivable that these uses, plus 

other less exciting salvage uses such as power for a space manufacturing base or 

space habitat, could provide sufficient demand for salvage use of an entire fleet of 

60 5CW SPS satellites. 

The SPS rectennae will most likely all be salvaged. The salvage will include 

recovery of steel and aluminum which have a combined value of about $290 million 

(at current prices) less removal cost plus recovery of the land. Taking the removal 

cost to be 25 percent of value (and adding discounting) the net salvage value of 
12 

these materials would be about $67 million. It is likely, however, that the cost of. 

removing the concrete for recovery of the land would be approximately equal to the 

net value of the steel and aluminum. Thus the principal salvage value of the 

rectennae is likely to be the present value of the land referenced to the initial 

operation date of the system. This is approximately $33 million* at a land value of 

about $1,000 per acre. 

A more valuable salvage use of the rectennae would be their reuse with new 

SPS satellites. In this case, especially if existing concrete footings and other 

components are reusable, the salvage value of the rectennae could approach 

30 percent of their new cost. Since the rectennae cost represents about 26 percent 

of the total SPS cost of about $13.9 billion, this value could approach $1.1 billion. 

If only land and the rectenna support structures are salvageable, the salvage value 

is about $620 million. This lower number allows substantial evolution to occur in 

the rectenna technology. 

Finally; those items which are not salvaged must be disposed of. The disposal 

options considered and their respective costs are given in Table 1.3. Five disposal 

options are considered. Disposal to L4 or Lg, the stable (equilateral) libration 

points in the earth-moon system would provide a location where the satellites 

might be recovered at some point in the distant future and salvaged for some, 

presently unknown, use. No stationkeeping or control of the satellites would be 

necessary once they are in this orbit. The second disposal option presented is to 

boost the satellite to an orbit above GEO. Twice GE0 is presented arbitrarily. 

The AV required is obviously a function of how high the satellite is boosted and the 

value provided is nominal. This orbit could utlimately require some stationkeeping 

* 

Corresponds to WBS item 1.4.1.1.1 in the Rockwell International cost estimate. 
13 

OPTION 

SUPRA-GE0 (2X) 

HELIOCENTRIC 

ORBIT 

EARTH REENTRY 

TARI F 1.3 BICPOSN OPTIONS AJ#D COSTS 

3.23 

1.75 66 

125 

REMARKS 

3.23 SATELLITE IS REClOVED FOREVER BY IMPACT 

ON LUNAR SURFACE 

-5.00 SOHEYHAT MIRE EXPENSIVE BUT REWOVAL IS 

PERMANENT 

6.03 K)ST EXPENSIVE OPTION MD PROBABLY WJT 

ACCEPTABLE DUE TO ENVIRONMENTAL AND 

RISK CONSIDERATIONS 

AV (VELOCITY INCREMENT) DEPENDS ON MISSION WOE. NUnBERS PRESENTED ARE BASED ON NICE IHPLUSIVE AV 

RCQJIRMNTS YHICH APPROXIWATE CONTINUOUS LOU TKWST AV. LWER IMPULSE REpUIREMENTS CQULO BE 

A!ZHIEVED BY LENGTHENING TRIP TIME. THIS UUJLD REDUCE PROPELLANT-ASSOCIATED COSTS WI INCREASE MISSION 

ASSCK IATED COSTS. THE MET EFFECT WOULD BE SOME REDUCTION IN TOTAL DISPOSAL COST. HENCE, COSTS 

PRESENTED ARE PROBABLY SWEWliAT CONSERVATIVE. 

STABLE LOCATIONS, SATELLITES COULD BE 

AVAILABLE FOR SALVAGE AT SOME FUTURE 

DATE, NO STATIONKEEPING NECESSARY 

LOU AV REQUIREMENTS BUT MNY REQUIRE 

SOME FORM OF ACTIVE CONTROL OR REWVAL 

AT A DISTANT TIME IN THE FUTURE 

activity; however, this activity might be very minimal (once every 1000 years, for 

example, depending on requirements). 

The third and fourth options dispose of the satellite forever by removing it 

from geocentric space. These could be desirable options if it becomes important to 

assure that no future concern need be given to the satellite. 

The final disposal option, earth reentry, is probably the least desirable from 

not only the aspect of cost --it requires the highest velocity increment--but from 

environmental and risk concerns as well. This disposal mode is unlikely to be 

implemented. 

1.4 Conclusions and Recommendations 

The conclusions and recommendations with respect to the demonstration 

satellite are as follows. The preferred salvage use is to use the demonstration 

satellite as a power source for a laser space transportation system. This will 

require installation of a laser power transmitter on the satellite. Accordingly it is 

recommended that the demonstration satellite be equipped with both a microwave 
14 . 

power transmitter and a laser power transmitter and be used to demonstrate both 

SPS configurations. Upon completion of the demonstration, the microwave power 

transmission system could be salvaged for use on a full-scale SPS satellite if the 

microwave SPS option is found desirable. The demonstration vehicle, however, 

,would remain in GE0 and, using the laser power transmission system, power laser 

rockets for LEO to CEO transportation. 

The value of the recommended salvage use is strongly dependent on the 

continuation of the SPS program, but even in the absence of a continuing SPS 

program, it appears sufficient to justify the development of a laser space transportation system exclusive of the SPS demonstration project. For planning purposes 

it is reasonable to assume that this salvage use will offset about 80 percent of the 

on-orbit cost of the demonstration satellite hardware. 

The conclusions and recommendations with respect to the full-scale satellites 

are as follows. Several potential salvage uses exist for full-scale SPS satellites, 

each with a salvage value ranging up to about $3 billion. Preferred salvage uses 

appear to be use as a power supply for a laser space transportation system, use as a 

power supply for powering aircraft on oceanic routes, use as a power supply to 

recover Amor and Apollo asteroids and use as a power supply for a high-energy, 

high-vacuum physics laboratory in space. 

The average salvage value of an SPS satellite appears to be in the range of 5 

to 10 percent of the satellite capital cost or about $500 million to $1 billion. Some 

specific uses, however, may provide significantly higher salvage values, but they 

are likely to be limited to only a few satellites. 

A basic theme which seems to dominate the salvage value results is that the 

uses which utilize the entire satellite intact have a higher value than those 

which require segmenting the satellite. The more the satellite is cut up, the less it 

appears to be worth as salvage. 
In any event, if it becomes necessary to dispose of SPS satellites, a number of 

disposal options appear feasible. The cost of disposal is on the order of 

$100 million. This amount has a present value referenced to the initial -operation 

date of the satellite of about $30 million or only about 0.3 percent of the capital 

investment cost of the satellite. 

It is clear from the above analysis that an assumption of zero net salvage and 

disposal cost for the SPS satellites is conservative. A less conservative assumption, for purposes of comparing SPS to alternative systems, would be to take a net 

salvage value between 5 and 10 percent of satellite capital investment cost. 

1.5 Backup Documentation 

The remaining sections of this report provide backup documentation to the 

results shown above. Both in review of the backup documentation and interpretation of the above results, the reader should keep in mind that the analyses and 

results presented here are based upon long-range projections of space and other 

activities and thus contain considerable uncertainty. 
16 

2. A POST-2000 MISSION MODEL 

Oscar Morgenstern once said, “Predicting things is very difficult, especially 

the future.” Yet, if one is to establish the salvage value of SPS demonstration and 

full-scale satellites, one must describe the environment within which these 

satellites are salvaged. At the very least, this means identifying a space mission 

model for the time period during which the salvage operation will take place. 

Basically this time period may be divided into two parts: the years 2000 to 2030 

during which time the principal object of salvage is the SPS demonstration 

satellite; and the period 2030 to 2060, and possibly beyond, when full-scale SPS 

satellites would become available for salvage. 

To begin with, one should recognize that these time frames, at least in terms 

of specific economic projections, are quite far in the future. The earlier time 

frame begins 20 years from now and spans a period of 30 years, ending half a 

century from today. The second period, beginning in the year 2030, is a period of 

projection that is one-half a century and more in the future. On the scale of life of 

five-year and ten-year plans, and of long-range planning that does not go beyond the 

end of the 20th century, it is, for all practical purposes, impossible to develop a 

mission model containing specific space missions. Rather, over the period 2000 to 

2030, projections of space activities are highly uncertain, although there is some 

hope to identify and establish general trends. These trends can be identified on the 

basis of existing technologies and technology projections for the relatively near 

term. For example, an operational space transportation system based on the Space 

Shuttle and advanced Shuttle derivatives is likely to lead to reduced costs for space 

activities and, subsequently, to an increasing level of commercial business in space. 
17 

Furthermore, there is some hope for identifying the major directions which this 

“industrialization of space” will take. 

Beyond the year 2030, however, one’s ability to project even general trends 

diminishes greatly. A fifty-year period is sufficient for major new and totally 

unforeseen technologies to develop and become commercialized. Without specific 

knowledge of these technologies (and that knowledge cannot be had today), 

projections of post-2030 space activities are entirely speculative. It is with the 

above qualifications that the following projections of future space activities are 

made. The first steps in making a long-range projection of space activities is to 

determine where the impetus for such activities will arise. At the present time 

funding for space activities derives almost entirely from national governments; 

principally the U.S. and U.S.S.R. U.S. Federal Government expenditures on space, 

spanning both DOD and NASA, encompass about $6 billion for FY 1980.* Looking 

at free world activities and taking this $6 billion to be a measure of free world 

government sponsorship of space activities and assuming, furthermore, that at the 

very most this government sponsorship is unlikely to accelerate at a real rate of 

growth greater than 3 percent per year, one sees a potential level of governmentsponsored activitiy in space by the year 2060 of only some ten times larger, or $60 

billion per year (1980 $1, than the present amount. A space program sponsored only 

by NASA and DOD (assuming that they exist in the year 2060) at the level of $60 

billion per year could possibly support some salvage activities on SPS satellites, but 

they would be severely limited. 

It is highly unlikely, however, that one would be faced with the problem of 

salvaging SPS satellites in a space program that is principally funded by NASA and 

DOD, and to a lesser extent by other governments. The simple fact is that one 

*The Budget of the United States Government, Fiscal Year 1980. 
18 

would not be concerned about salvage of SPS satellites unless an SPS program is 

indeed implemented. Furthermore the presence of an SPS program infers, in 

itself, the successful development of a number of space-based technologies that 

should lead to widely expanding use of space by the private sector. The transition 

from federal funding to private sector funding for space activities is already 

evident with communications and information satellite programs, and the acceleration of these trends due to improved space transportation technologies is clearly 

forthcoming. The successful implementation of an SPS program assures that highly 

advanced technologies in.low cost space transportation including both earth to LEO 

and LEO to CEO will have been successfully developed. In addition, technologies 

for the construction and deployment of large-scale space structures, long duration 

manned facilities and low cost solar cells are assured. These technologies will be 

available by about the year 2000, or at the time of implementation of the SPS 

system, and will thus contribute to the economic development of space in the 

intervening period (2000 to 2030). 

At the present time the private sector is making significant strides forward 

in space-based activities with a focus on communications and data gathering. 

Present communications activities in the private sector include not only COMSAT 

(a quasi-private sector organization) but a number of U.S. corporations such as 

Western Electric, RCA, IBM and so on. These activities should begin to mature 

around the year 2000 with the implementation of large communications platforms 

in geosynchronous orbit. Both these and lower altitude platforms will also probably 

be implemented by the private sector for data collection. The data collection 

systems will include both natural resources and environment monitoring such as the 

LANDSAT and SEASAT satellites have done to date. It is conceivable that the 

communications industry alone could grow to a level of expenditure of between 
19 

$15 billion and $100 billion per year by the year 2060, and that data collection 

activities would be on the order of $10 billion to $100 billion per year by that time. 

Space-based communications expenditures are likely to grow in order ‘to 

handle personal communications, business data transfer and video communications 

including teleconferencing. The advantages of teleconferencing in business applications are fast becoming apparent and this mode of communication is likely to 

supplant a significant fraction of business travel. It is an interesting aside to note 

that advanced communications activities such as this are highly energy conservative. By the year 2060 it is conceivable that between 30 and 60 large communications platforms will be in place, many in geosynchronous equatorial orbit, but some 

in other orbits to serve more extreme latitudes. The present desire for geostationary satellites is clearly shown in Figure 2.1. By the year 1990 some 150 

satellites will have served various functions, mostly communications, in that orbit. 

FIGURE 2.1 GEOSTATIONARY SATELLITES--TO DATE AND PLANNED 
20 

As data collection in space becomes an economic reality, it is rapidly found 

that satellites can produce prodigious quantities of data. A single advanced earth 

resources satellite, for example, might produce as much as lo9 bits of data per 

second. Clearly, no human will ever examine all of the available data. Thus it is 

reasonable to expect a substantial amount of space-based data processing in order 

to reduce these data to an informational level upon which decisions can be based. 

Space-based data processing in large (by current standards) computers, co-located 

with the data collection sensors in space, thus enabling the communications link 

with earth to carry minimal amounts of processed data, is likely. 

An intriguing and totally unpredictable area of space activity is space-based 

manufacturing. Space, of course, offers a unique environment including high 

vacuum and zero gravity which should be of considerable benefit to particular 

manufacturing processes. The unfortunate fact at this time is that since this 

environment has heretofore not been available to the private sector, the technology for using it has not been developed. As a result, to date, NASA and others 

have studied a variety of products that might potentially be manufactured in space 

and found that indeed there may be benefits in doing so. Unfortunately there is a 

considerable time lag between today and the date at which commercial spacebased manufacturing facilities will be available to the private sector. Thus the 

principal conclusion to which one might arrive is that there are many potential 

products that could be beneficially manufacturered in space, but none of them are 

the products that have been examined to date, nor are they products that one 

would choose to manufacture in space based upon what is known today. Accordingly the annual expenditures on space-based manufacturing is highly uncertain at 

this time. Conceivably they could be as low as a fraction of a percent or as high 

as possibly 10 percent of the gross national product, say a range of $10 billion to 

$500 billion per year. 
21 

The third major category of private sector activity in space is energy. If SPS 

is implemented, these expenditures will be quite high. For example, the operation 

and maintenance expense on a fleet of 60 SPS satellites will be on the order of $30 

billion per year. Capital construction of new SPS satellites could add another $20 

billion to $50 billion or more to this amount. Worldwide implementation of SPS on . 

a large scale plus construction of space-based energy systems for lunar exploration, 

asteriod retrieval and space habitation could increase this amount to as much as 

$250 billion per year. 

In addition to the above four categories of space-based activities, there are a 

number of other activities that are likely to occur in space. These include physics 

and astronomy, solar system exploration, basic and applied research, space tourism, 

space-based navigation systems and so on. These miscellaneous activities are 

likely to involve expenditures in the range of $5 billion to $50 billion per year by 

the year 2060. Summing these figures as shown in Figure 2.2, the private sector 

potential activities in space range from a low of about $65 billion per year in the 

year 2060 to a high of about $1 trillion per year. 

ANNUAL 

EXPENDITURE 

ON SPACE, 

19806 

NASA 

DOD 

1980 2060 

YEAR 

PRIVATE SECTOR POTENTIAL 

ENERGY $25- 2508 

COMM . 15-100 

DATA 10-100 

&AN. lo- 500 

MISC. 

5655~iOo500 

1 3X/YR REAL GROWTH 

FIGURE 2.2 POTENTIAL SPACE ACT.IVITY LEVELS, 1980-2060 
22 

The major observation which one draws from Figure 2.2 is that dramatic 

growth in space-based activities, if such growth indeed occurs between now and the 

year 2060, will derive mainly from private sector ventures undertaken because they 

are economic. The challenge to NASA is to focus space programs between now and 

the year 2000 in such a way as to promote the economic utilization of space. 

Given the proper opportunities, it is conceivable that as much as 20 percent of the 

gross national product in the year 2060, or say $1 trillion per year, will be derived 

from space-based activities. On the other hand, without proper encouragement and 

technology development from NASA and other government agencies, this amount 

could be very much smaller and the government could still dominate annual 

expenditures on space activities as late as the year 2060. 

2.1 The Period 2000 to 2030 

In the context of the above discussion, it is possible to make useful 

observations on space-based activities during the period 2000 to 2030. A principal 

activity in space during this period will quite clearly be space-based communications, data collection and data processing. It is also evident that the current trend 

of placing an ever increasing number of relatively small satellites in geosynchronous orbit cannot continue. Communications and data needs will be satisfied 

in the future by the use of large geosynchronous platforms rather than by a number 

of smaller satellites. Accordingly the following general trends are identified for 

the post-2000 time period: 

1. Space will be populated with fewer larger spacecraft. This will be 

accomplished by transition to large mutli-purpose platforms. 

2. Bandwidth limitations will be overcome by using higher power levels 

and spot beams. 

3. Multi-purpose platforms will not be co-located with SPS due to conflicting requirements such as the potential need for turning SPS 

satellites out of the sun during maintenance periods. 
23 

4. Mutli-purpose platforms will occupy many important orbits, not only 

GEO. 

5. On-orbit servicing capability will be maintained for all multi-purpose 

platforms. Because of their high value, downtime on these platforms 

will be extremely expensive. The balance between man and robotics for 

providing on-orbit servicing capability is very uncertain at this time. 

6. Many activities in space will be internationally sponsored, and it is 

likely that large geosynchronous platforms will be considered multinational territory. 

7. Many of the activities performed in space in the post-2000 period will 

be performed there because it is economic to do so independent of 

government funding. These activities will thus represent a significant 

transformation of space-based activities from the government to the 

private sector. 

8. A fully reusable space transportation system and multi-purpose platforms will dramatically lower the cost of the space activities and thus 

promote increasing private sector investments in space. 

9. System complexity will shift from the ground segment where it is 

presently to the space segment, enabling ground-based users to participate in the use of space-based communications and data collection with 

relatively low investment. However this does not infer that the 

majority of expenditures on a particular system will be on the space 

segment. To the contrary, the lowering of costs for ground-based users 

is likely to increase the number of ground-based users dramatically, thus 

maintaining the preponderance of expenditures on the ground segment. 

For example, if the worldwide market for personal communicators at 

$100 per communicator is 100 million units, a total expenditure on the 

ground,segment of some $10 billion will ensue. This might be compared 

to an expenditure on the space segment in support of these communicators of, say, $5 billion. 

Of particular interest in the post-2000 time period are geosynchronous 

platforms. It has already been observed that geosynchronous orbit will be 

dominated by large platforms during this period. The seeds of this transformation 

have already been sown, and it is expected that during the late 80s and early 90s a 

number of U.S. domestic and Intelsat platforms in the 25 kilowatt class will be 

placed in geosynchronous orbit. During the period of the mid-90s to about the year 

2010, the placement of some five to ten larger platforms in the 100 to 500 kW class is 

likely. Beyond the year 2010 one can look for the replacement of the earlier 
24 

platforms by a new class of platforms in the 1 to 5 MW class, growing to a total of 

some 15 to 30 platforms by the year 2030. The larger platforms are likely to be 

manned either by robots or by two-man crews rotated periodically. The purpose’of 

man will be to effect immediate service, repair and maintenance as necessary to 

keep the platform properly functioning. The cost of the advanced platforms will be 

in the range of $2 billion to $10 billion each, and they will have a structure and 

power supply life approaching 50 years with other systems being updated on about a 

ten-year cycle. 

The advanced geosynchronous platforms will be supported by a manned 

geosynchronous facility which is also likely to be a space-based manufacturing 

facility to manufacture and rebuild components and subsystems for the geosynchronous and other space platforms. As a result it is likely that 50 to 500 persons 

will be stationed in geosynchronous orbit in support of the geosynchronous 

platforms. 

Spacecraft power and lifetime trends to date, as shown in Figure 2.3, clearly 

reflect these trends. Twenty-five kW platforms are presently in the planning 

stage* and studies on 100 to 500 kW platforms for the late 1990s time period have 

++ 

already been performed. The continuing improvements in lifetime and growth in 

power levels shown in Figure 2.3 are fully compatible with SPS-based technologies. 

It is interesting to consider the traffic necessary to support the geosynchronous platforms that are likely to be put in place in the 2000 to 2030 period. 

* 

Payloads Requirements/Accommodations Assessment Study for Science and 

Applications Space Platforms, Second Quarterly Review, TRW, June 10, 1980. 

Third Quarter Briefin 

f 

: Conceptual Design Study--Science and Applications 

Space Platform (SASP , McDonnell Douglas Astronautics Company, June 11, 

1980. 

** 

Space Industrialization --Background, Needs and Opportunities, Rockwell International, Report No. SD-78-AP-0055, April 14, 1978. 
25 

10,000,000 

5,ooo.~ 

1,OOo.ooo 

500,000 

100,000 

50,000 

E 

2 10.000 

E 

s 

5.000 

a. 

x 1.000 

500 

100 

50 

10 

l INTELSAT (YR OF FlR!ZT LAUNCH) 

- .-.e-- 

. REFERENCE MISSIONS ,l 

m nmFl 

SOURCE: NASA ADVISORY COWCIL 

SUBCOMMITTEE ON POWER TECHNOLOGY 

FOR FUTURE SYNCHRONOUS SATELLITES 

AND PLATFORMS, MINUTES OF MEETING 

DEC. 13 L 14, 1978. 

1965 1975 1985 1995 2005 2015 2025 

YEAR 

FIGURE 2.3 HISTORICAL AND PROJECTED GROWTH OF SPACECRAFT 

POWER AND LIFETIME 

These traffic requirements are shown in Table 2.1. This table reflects the fact 

that there are two fundamentally different classes of payloads which need to be 

transported to geosynchronous orbit. The first class involves durable goods such as 

the materials for construction of new platforms. It is probably economic to 

transport these materials between LEO and CEO using a low-thrust electric cargo 

orbit transfer vehicle (COTV). The implications in this decision indicate that the 

cost of capital for the durable goods during the period of transportation is more 

than offset by the cost savings afforded by the electric COTV. Nondurable goods, 

however, such as man and his logistics, require more rapid forms of transportation. 

The present option for the personnel orbit transfer vehicle (POTV) involves the use 
26 

. UATERIAL FOR COWSTRUCTICM OF NEY 

PlATFtWS (50,000-2OO.CJODffi EACH) 

. REPLACE#NTS.CH&JGEWTSANDSPARES 

(5% CMNGEOUT/YR, MLF BROUGHT UP 

l k4N (100-1000 PERSON-TRIPS LEOGEO--6 Ml. YORK CYCLE, 50-5DO 

6EO-GE0 PERSDN-TRIPS) 

l LOGISTICS (1800 KG/PERSON-YR) 

l COTV AND POTV PAYLOAD WYIWLES 

- COTV (52 OF PAYLOAD) 

25.000 - 3oo.ooo 25,000 - 3D0,ooo 

4wm - 300,ooo 

8,ooO- 80.000 

30,000 - 300,ow 

177.000 - 1,775.DOo 116,000 - 1,106.000 

- COTV TRAFFIC ( 47,DOO - 473,000) ( 68,OOfl - 625,000 

l PROPELlAM 

- cow (~EcTRIc, 10,000 SEC) 6,000 - 60,DOO NIL 

- POTV (CHEHICAL. 460 SEC) 400,000 -4,oDO.ooD 1,oOD - lO.MKl 

of chemical propellants (oxygen and hydrogen) to enable LEO to CEO trips to be 

made on the order of one-half day. It is evident from Table 2.1 that rather large 

quantities of chemical propellants are necessary to support a POTV system. It is 

thus apparent that alternatives to the use of a chemical POTV could be quite 

advantageous. 

2.2 The Post-2030 Time Period 

Very little more can be said about space activities in the post-2030 time 

period than has been noted already above. It is likely that this period will see the 

widespread use of space by man including space habitation and utilization of 

extraterrestrial resources. It is also likely that many scientific endeavors will move 

into space: astrophysics, astronomy, high-energy physics and biological research 
27 

are examples. It is this context in which salvage value of SPS satellites was 

considered. 
28 

3. SPS DEMONSTRATION SATELLITE SALVAGE ALTERNATIVES 

According to the Rockwell International SPS development program. plan,* the 

completion of the SPS Technology Advancement phase by 1990 will provide the 

technical confidence to proceed with a pilot plant demonstration phase. The 

primary objective of this development phase would be the demonstration of all SPS 

technologies to those utility firms and consortiums that would ultimately capitalize 

and operate the production or full scale operational system. 

The pilot-plant or demonstration satellite will be constructed in low earth 

orbit using a heavy lift launch vehicle (HLLV) for mass transportation and 

construction support systems. The demonstration satellite will be transferred to 

geosynchronous orbit by an on-board electric propulsion system. The demonstration satellite will operate in the same mode as the full-scale SPS satellite by 

directing a microwave power beam at a total power level of a few hundred MW to a 

standard modular segment of the proposed operational ground rectenna. The 

demonstration/operational period may range from six months to a few years, during 

which time the SPS elements of the full-scale solar power satellite will be operated 

in the operational environment. Operational data will provide the quantitative 

basis for analyses which will support full SPS commercial capability. 

The initial step will be to establish a base in low-earth orbit that is capable 

of constructing the demonstration satellite. The demonstrator satellite, shown near 

completion in Figure 3.1, is sized to the projected electric orbit transfer vehicle 

(EOTV) power level of 335 MW at the array. Allowing for radiation degradation 

*Satellite Power Systems (SPS) Concept Definition Study, Final Report, Vol. 1, 

Rockwell International, Contract NAS&32475, March 1979. 
29 

FIGURE 3.1 SPS DEMONSTRATION SATELLITE IN FINAL PHASES OF 

CONSTRUCTION (SOURCE: ROCKWELL INTERNATIONAL) 

and power distribution losses, power to the microwave antenna will be approximately 285 MW. Microwave transmission losses further reduce this value to about 

230 MW at the rectenna, resulting in recovery of 8 h4W of power for a sparsely 

populated 7-km-diameter demonstration rectenna or 2 MW of power for a 1.7%km 

demonstration rectenna. 

The demonstration satellite is a single unit or bay of the operational SPS 

which consists of 30 such bays as shown in Figure 3.2. A list of the basic items 

which comprise the demonstration satellite and their related DDT&E and first unit 

costs are summarized in Table 3.1. The mass properties of the full-scale and 

demonstration satellites are summarized in Table 3.2. 

Because of the large investment in the demonstration satellite and the 

associated transportation costs and the on-orbit capability that will exist, there is 
.w I -n-m - .__. --.-- _- .._. ---- 

FIGURE 3.2 FULL-SCALE OPERATIONAL SPS SATELLITE CONFIGURATION 

(SOURCE: ROCKWELL INTERNATIONAL) 

a natural concern as to the alternative uses of the demonstration satellite upon 

completion of the demonstration program, and the economic value associated with 

these uses. The following sections discuss alternative uses, and the value derived 

therefrom, to which the demonstration satellite may be put upon completion of the 

demonstration program. Four alternative uses have been considered, namely: 

1. Use of the demonstration satellite as the first building-block of the first fullscale SPS satellite. The economic value, or salvage value, of the demonstration satellite derives primarily from the costs which would be foregone in the 

construction of the full-scale satellite through the incorporation of the 

demonstration satellite into the full-scale satellite. 

2. Use of the demonstration satellite as a source of power for non-SPS space 

activities. This use requires the systematic disassembly of the demonstration 

satellite and transferral and use of the disassembled power subsystems as 

power supplies in other space missions. Here the salvage value of the 

demonstration satellite derives primarily from the costs (both hardware and 

associated transportation) foregone by the other space missions through their 

use of the demonstration satellite power subsystems. 
- - 

TABLE 3.1 DEWONSTRATION SATELLITE COST STRUCTURE* 

HORK BREAKDOYN 

STRUCTURE NLWBER 

SWITCHGEAR ii CONVERTERS--E.C. 

CONDUCTORS & INSULATION--E.C. 

ACS HARDWARE--E.C. 

SLIPRINGS--PRECURSOR 

PRIMARY STRUCTURE--INTERFACE 

1.1.9.1.10 SECONDARY STRUCTURE--INTERFACE 

1.1.9.1.11 MECHANISMS--INTERFACE 

1.1.9.1.12 CONDUCTORS L INSULATION 

SLIPRINGS BRUSHES--PRECURSOR 

PRIMARY STRUCTURE--POWER TRANS. 

1.1.9.1.15 SECONDARY STRUCTURE--POUER TRANS. 

1.1.9.1.16 TRANSMITTER SUBARRAYS--KLYSTRONS 

1.1.9.1.17 SWITCHGEAR & CONVERTERS--P.T. PRECURSOR 

CONDUCTORS & INSULATION--P.T. PRECURSOR 

BATTERIES--P.T. PRECURSOR 

1.1.9.1.20 ULATION--PRECURSOR 

*SOURCE: SATELLITE POWER SYSTEMS (SPS) CONCEPT DEFINITION STUDY, VOL. II, ROCKWELL INTERNATIONAL, MARCH 1979. 

+1977 DOLLARS. 

w 

c 

I 
. . _ . . .-- 

32 

TABLE 3.2 MASS PROPERTIES OF FULL-SCALE AND DEMONSTRATION SPS 

SATELLITES (lo6 KG) 

SECONDARY STRUCTURE 

SOLAR BLANKETS 

CONCENTRATORS 

ON 8 CONDITIONING 

GEMENT & CONTROL 

RY STRUCTURE 

DARY STRUCTURE 

TRANSMITTER SUBARRAYS 

POWER DISTRIBUTION & CONDITIONING 

THERMAL CONTROL 

*SOURCE: SATELLITE POWER SYSTEMS (SPS) CONCEPT DEFINITION STUCY, 

FINAL REPORT, VOL. II, ROCKWELL INTERNATIONAL, CONTRACT NAS8-32475, 

MARCH 1979. 

+DEMONSTRATION SATELLITE SCALED FROM FULL-SCALE SATELITE ACCORDING 

TO THE RATIO OF POWER GENERATED. 
33 

3. Use of the demonstration satellite as a power supply for a laser orbit-to-orbit 

transportation system. A laser orbit-to-orbit transportation system would 

derive value through transportation cost savings primarily on the cost of 

transporting otherwise-needed propellants to LEO. 

4. Use of the demonstration satellite as a source of space-based materials. The 

salvage value of this use derives from transportation costs and material costs 

which may be foregone by using the basic materials existing in the demonstration satellite. 

3.1 Growth to Full-Scale Satellite 

It is currently envisioned that the demonstration satellite will consist of an 

energy conversion segment, an interface segment and a power transmission 

segment. The energy conversion segment will consist of primary and secondary 

structure, concentrators, solar blankets, switchgear and converters, conductors and 

insulation, attitude control and information management subystems. The interface 

segment includes the primary and secondary structure, mechanisms, conductors/insulation and slipring brushes. The power transmission segment will be representative of the full-scale satellite antenna to the extent of using identical components. 

It will include structures, transmitter subarrays, power distribution and conditioning, batteries, insulation and phase control elements. 

Current plans call for growth of the demonstration satellite into the first 

full-scale SPS satellite. By growing the demonstration satellite into the first fullscale satellite, certain costs may be foregone (that is, a cost item that would have 

to be incurred if the demonstration satellite were not available for use, would not 

be incurred since the demonstration satellite & available for use) whereas others 

may be incurred. The present value of the net of these costs referenced to the 

initial operation date of the demonstration satellite, is the salvage value that may 

be derived from this use of the demonstration satellite. It is assumed throughout 

the following that the demonstration satellite is in orbit and all associated DDT&E 

and first unit costs are sunk. 
- 

34 

The salvage value of the demonstration satellite when used as an initial 

element in a full-scale satellite is summarized in Figure 3.3 and discussed below. 

The salvage value, SV, is 

sv = PVI + PV2 - PV3 - PV4 

wheie PVI is the present value of the full-scale satellite costs that may be 

foregone. PVl accounts for the hardware costs for providing a capability 

equivalent to the demonstration satellite capability and the transportation costs 

associated with transporting this equivalent capability. The demonstration satellite capability must be adjusted for degradation effects which are a function of 

time (the time interval to the deployment of the first full-scale satellite) and both 

hardware and transportation costs must be adjusted for learning effects (assumed 

to be a function of time) that may also take place during this interim period. PV2 

is the present value of consumer surplus benefits that will result if the marginal 

VALUE OF 

SV- SPS DEt40 = I SATELLITE I 'RESENT VMUE OF INITIAL INVESTMENT FOREGONE 

a SPACE HARDWARE COSTS FOR PROVIDING CAPABILITY ECJJIVALENT TO 

mo-sps (ADJUSTED FOR LEARNING a TIMING) 

l COSTS FOR TRANSPORTING EQUIVALENT OF DEW-SPS II - PVl 

I PRESENT VALUE OF CONSUMER SURPLUS BENEFITS 

I 

+ l REDUCED PRICE OF ELECTRICITY FROM USE OF DEMO-SPS IN THE 

TIME INTERVAL TO ON-ORBIT CONSTRUCTION OF OPERATIONAL SPS - PV2 

I 

-I 

PRESENT VALUE OF INCREASE IN CONSTRUCTION (INTERFACE) COSTS 

o CANNOT TAKE ADVANTAGE (AT LEAST FOR INTERFACING WITH DE!@- 

I 

-PV3 

SPS) OF KNOWLEDGE GAINED FROM DE140 PROGRAM 

- PRESENT VALUE OF INCREASE IN DEMO-SPS INVESTMENT COST TO 

ACHIEVE RELIABILITY CHARACTERISTICS OF OPERATIONAL SPS - PV4 

FIGURE 3.3 SALVAGE VALUE--GROWTH TO FULL-SCALE SATELLITE 
35 

cost of energy from the SPS system is below that resulting from other energy 

sources. The consumer surplus benefits are directly proportional to the price 

differential, the energy produced and the time interval from demonstration 

completion to on-orbit construction of the operational satellite. PV3 is the present 

value of possible increases in construction (interface) costs that result from not 

being able to take advantage of knowledge gained from the demonstration program. 

PV4 is the present value of the increase in demonstration satellite investment cost 

to achieve the same reliability characteristics that would be achieved by the first 

full-scale operational satellite. Since no information is available on demonstration 

satellite cost in terms of reliability characteristics, PV4 has been assumed to be 

zero. The detailed value model is indicated below together with definitions of the 

variables and the nominal values utilized in the analysis. It should be noted that 

the annual transportation investment cost is treated parametrically and is obtained 

by spreading the cost to deliver 1.618 X lo6 kg to geosynchronous orbit over a three 

year period (30%, 40% and 30% respectively). The basic range of transportation 

cost has been considered from 0 to 100 $/kg predicated upon the assumption that 

10~ transportation costs will have to be achieved in order to proceed with an 

economically viable full-scale operational SPS system. 

PV 1 = (IOD-IOC)L1 * ( l-&)loD-loC + $ DCSTIHi + (l+& DR I-i 

i=l 

+ (IOD-IOC)L2 + 2 DCSTITi * (l+g )I-’ 

i=l 

where L 1 = (log 10LINVH-2.0)/leg lo2. 

L2 = (loglOLINVT-2.0)/loglo2. 
36 

IOD-IOC 

PV2 = 876 * DSPSP * s (PCONEi-PSPSEi) * (1 DR 2000-IOC-i -gj)’ * (I+m) 

i=l 

PV3 = CINTF * PclI;OTF * DSPSP * (1,s )2000-10D 

PV4=0 

Variable 

DR 

IOC 

IOD 

DCSTIHi 

DCSTITi 

LINVH 

LINVT 

PCONE. 1 

PSPSEi 

DSPSP 

Definition 

Time subscript (years) 

Number of years from time 

of first unit cost expenditure 

to 2000 

Discount rate (%) 

Date of initial operating 

capability for supplying 

electric energy to the grid 

from the demonstration 

satellite (year) 

Date of initial operating 

capability for supplying 

electric energy to the grid 

from the SPS operational 

satellite (year) 

Annual nontransportation 

investment cost of demonstration satellite ($/year) 

Annual transportation 

investment of demonstration 

satellite ($/year) 

Cumulative average learning 

rate for SPS nontransportation 

costs (%) 

Cumulative average learning 

rate for SPS transportation 

costs (46) 

Average cost of energy from 

non-SPS sources displaced by 

SPS in year i (mills/kWh) 

Cost of energy from SPS in 

year i (mil.ls/kWh) 

Demonstration satellite power 

available to grid (kW) 

Nominal Value 

3 

4 

1998 

2000 

521X106 (1996) 

695X lo6 (1997) 

521X106 (1998) 

See Text 

90 

90 

Differences 

Assumed 

Small 

162X 103kW 
37 

Variable Definition _Nominal Value 

D 

CINTF 

PCINTF 

Percent power degradation 

(due to both random nonreplaced failures and radiation 

effects) of SPS power supply 

per year (%/year) 

1 

Cost per kilowatt for interfacing 

operational SPS satellite power 

modules with other operational 

SPS satellite power modules ($/kW) 

-- 

Percent increase in cost of 

interfacing operational SPS 

power modules with demonstration satellite power modules (%) 

Assumed 

to be zero 

The results of the analysis are illustrated in Figure 3.4 where the present 

value of the demonstration satellite is indicated as a function of transportation 

cost ($/kg) and the time interval between the initial operations dates of the fullscale operational satellite and the demonstration satellite. The basic conclusion 

that may be reached from the data presented in Figure 3.4 is that the salvage value 

($l.l-$1.7 billion) of the demonstration satellite may be a large percentage of the 

demonstration satellite on-orbit cost (first unit plus transportation cost). The 

salvage value may be in the range of 60-90 percent of the on-orbit cost of the 

demonstration satellite depending upon transportation cost achieved and the time 

interval from demonstration satellite operations to operation of the first full-scale 

SPS satellite. 

3.2 Demonstration SateI+ &e--as-a Power- Supply for Non-SPS Space Activities -~_-- .~ 

If the demonstration satellite is not utilized as an initial ‘element of a fullscale operational SPS satellite, it may serve as a source of power (335 MW) and 

major subsystems for other space activities. When used in this manner its value is 

a function. of the demand for space power and other major subsystems and the 

timing of this demand. The value of the demonstration satellite when used as a 

power supply for non-SPS space activities is the value of the power supplies and 
38 

.2000 

t 

2 YEARS 

INCREASING TIME BETYEEN 

CONSTRUCTION OF DEW L 

F/S SATELLITE (IOO-lot) 

01 I 1 

0 50 100 

TRANSPORTATION COST, $/KG 

FIGURE 3.4 PRESENT VALUE OF DEMONSTRATION SATELLITE WHEN USED AS AN 

INITIAL ELEMENT IN A FULL-SCALE SATELLITE 

major subsystems that would not have to be procured and transported for the other 

space activities less the specific costs associated with segmenting the demonstration satellite into the useful power modules and other major subsystems and the 

incremental costs of installing these on other mission spacecraft. 

Since it is not possible to accurately forecast the demand for space power in 

the 2000 to 2030 time frame, the demand has been treated parametrically in terms 

of MW required per year. This demand has been considered in the range of 1 to 

15 MW/yr as illustrated by the solid lines in Figure 3.5. The dashed curve in 

Figure 3.5 indicates the avaiIable supply, taking into account a l%/yr degradation in 

power and an assumed inefficiency (25% salvage loss) or loss resulting from the 

salvage segmentation process. The intersection of the supply and cumulative 

demand curves yields the number of years that the demonstration satellite power 
39 

3DO-335WEKlLPWER 

8 l'Z/YR DEGRAOATIOH 

I 252 SALVAGE LOSS 

B 

E 

e *cQ5 

2 

2 

= 5 WYR 

2DDo 2010 2020 2030 2040 

CALENDAR YEAR 

FIGURE 3.5 SUPPLY & DEMAND FOR POWER FROM 

DEMONSTRATION SPS SATELLITE 

supply will last (for example, at demand rates of 15, 10, 5 and 1 MU’/yr, the 

demonstration satellite power supply will last 12, 20, 33 and 96 years respectively). It was assumed for the analyses reported in the following paragraphs that the 

demonstration satellite would have a maximum life of 30 years for being able to 

remove portions of the power supply. 

The salvage value of the demonstration satellite when used as a source of 

power and other major subsystems for other space activities is summarized in 

Figure 3.6 and discussed below. The salvage value, SV, is 

SV=PVI-PV2-PV3-PV4-PV5 

where PVl is the present value of the non-SPS mission investment costs that may 

be foregone because of the utilization of the SPS demonstration satellite hardware. 

The costs that may be foregone include both the space hardware costs and the 
40 

I 

PRESENT VALUE OF NON-SPS MISSION INVESTMENT COSTS FOREGONE 

- 

l SPACE HARDWARE COSTS (POWER L OTHER SUBSYSTEllS) 

l TRANSPORTATION COSTS FOR SPACE HARDWARE 

- I 

\ 

PRESENT VALUE OF INCREMENTAL MISSION KAINTENANCE COSTS 

l RANDOM FAILURES 

m WEAROUT FAILURES 

-pv2 

PRESENT VALUE OF INCREMENTAL DEMONSTRATION SATELLITE 

OPERATION COSTS 

s -pv3 

a CONTINUING OPERATIONS 6 MAINTENANCE OF DEMONSTRATION SATELLITE 

PRESENT VALUE OF INCREASE IN MISSIUN OPERATIONS COSTS 

l SEGMENTING OF DEMONSTRATION SATELLITE POWER SYSTEM 

I 

-PV4 

l INSTALLING SEGMENTED DEMONSTRATION SATELLITE POWER 

SYSTEM ON MISSION SPACECRAFT 

- { 

PRESENT VALUE OF DISPOSING OF UNUSED PORTION OF DEMDNSTRATION SATELLITE > - PV5 

FIGURE 3.6 SALVAGE VALUE--SPS DEMONSTRATION SATELLITE USED AS A SOURCE 

OF POWER AND OTHER SUBSYSTEMS FOR OTHER ACTIVITIES 

transportation costs incurred in placing the hardware in the desired orbit. PV2 is 

the present value of incremental mission maintenance costs incurred as a result of 

using the demonstration satellite hardware in lieu of mission specific hardware. 

For this analysis PV2 has been assumed to be zero. PV3 is the present value of 

incremental demonstration satellite operations costs incurred as a result of continuing the SPS demonstration satellite operations throughout the salvage period 

and providing the necessary maintenance. PV4 is the present value of the increase 

in mission operations costs and includes those costs incurred to segment the 

demonstration satellite power system and to install the segmented power system on 

the other mission spacecraft. PV5 is the present value of the costs associated with 

disposing of the unused portion of the demonstration satellite. The detailed value 

model is indicated below with the definition of variables and nominal values for the 

variables also indicated. 
41 

PVl = CFAC + ATL@(lB) 

- AT 

+ CKG + MFAC * ATL1 * (I+@ *T 

+i 

i=l 

CKC + KCKW + lo3 + M * i(L1+L4) + (l+zJ-’ 

CKW * 103*M *iL2*(l+s) CKCSC + KGKW * lo3 *M+ 

i=l i=l 

(1 D, . -100 

+ i(L3+L4) + (l+DR )-I 

100 

where L@ = (loglOLCCF-2.0)/log102. 

Ll = (loglOLCKG-2.0)/log102. 

L2 = (logloLCKW-2.0)/log102. 

L3 = (loglOLCKGSG-2.0)/log102. 

L4 = (loglOLKGKW-2.0)/loglo2. 

PV2 = 0 

PV3 = IO3 * iv + CKWS + iL5 + CKWSI + iL6) * (l-&yi - CKWAII + i”} + 

(1 DR) +im 

where L5 = (loglOLCKWS-2.0)/log102. 

L6 = (loglOLCKWSI-2.0)/loglo2. 

L7 = (log10LCKWMI-2.0)/log102. 

PV4 = i SPSCOC + iL8 

i=l 

+ (I+!& 

where = (log loLsPsco-2.0)/log lo2. 

PV5 = CDIS + INMASS-MFAC-KGKW * IO3 

t * In (lm D ) - In(t) = In (;%?A) 
42 

Variable 

i 

t 

M 

P 

D 

DELTA 

DR 

CKGSG 

CKWS 

CKWSI 

CKWMI 

SPSCOC 

INMASS 

KGKW 

Definition 

Time subscript referenced 

to year 2000 (years) 

The time at which demonstration 

satellite power is consumed 

(years) 

Rate of increase in the demand 

for space power (MW/year) 

Power available from the demonstration satellite in 2000 for 

space operations (W) 

Percent power degradation (due 

to both random nonreplaced 

failures and radiation effects) 

(%/year) 

Percentage of the demonstration 

satellite power that may be 

efficiently utilized for other 

missions (%I 

Discount rate (%) 

Cost per kilogram for transporting 

power subsystem from the demonstration satellite orbit to mission 

orbit ($/kg) 

Cost per kilowatt for segmenting 

the demonstration satellite into 

useful size power modules ($/kW 1 

Cost per kilowatt for installing the 

demonstration satellite system 

segment on a mission spacecraft 

($/IN) 

Cost per kilowatt for installing 

non-SPS power system on a mission 

spacecraft ($/kW) 

Demonstration satellite continuing 

operations costs (during salvage 

operations) ($/year) 

Initial mass of demonstration 

satellite just prior to start of 

salvage operations (kg) 

Achievable power density of power 

system (kg/kW) 

Nominal Value 

See Figure 3.5 

Treated 

Parametrically 

335x lo6 

1 

75 

4 

Negligible 

152 

(See Appendix A) 

(See Appzzdix A) 

15 

0.6X IO6 

1.618X106 

,825 

(See Appendix A) 
Variable Definition -- 

T 

CKW 

CKG 

CDIS 

MFAC 

CFAC 

LCCF 

LCKG 

LCKW 

LCKGSG 

LKGKW 

LCKWS 

LCKWSI 

Time, measured from year 2000, 

when nonpower salvageable pieces 

are removed (years) 

Treated 

Parametrically 

Cost per kilowatt of power not 1.67X lo3 

including delivery costs (it is assumed (See Appendix A) 

that the cost of SPS and mission 

power are equal) ($/kW) 

Cost per kilogram delivered to Treated 

CEO from Earth ($/kg) Parametrically 

Cost per kilogram of disposing 

of nonsalvageable mass of the 

demonstration satellite ($/kg) 

Mass of usable demonstration 

satellite facilities (kg) 

Cost of usable demonstration 

satellite facilities ($) 

Small Compared 

to CKG 

87600 KG 

134x106 

Cumulative average learning 

rate for cost of other salvagaeble 

pieces of the demonstration 

satellite (%) 

90 

Cumulative average learning 

rate for cost per kilogram 

delivered to CEO from Earth (%) 

Cumulative average learning 

rate for cost per kilowatt of power 

not including delivery costs (%) 

Cumulative average learning rate 

for cost per kilogram for transporting power subsystem from the 

demonstration satellire orbit to 

mission orbit (96) 

Cumulative average learning rate 

for achievable power density of 

power system (%) 

Cumulative average learning rate 

for cost per kilowatt for segmenting 

the demonstration satellite into 

power modules (%) 

Cumulative average learning rate 

for cost per kilowatt for installing 

SPS segmented power module on 

mission spacecraft (%) 

90 

90 

90 

90 

90 

90 
44 

Variable Definition Nominal Value 

LCKWMI 

LSPSCO 

Cumulative average learning rate 90 

for installing non-SPS power system 

on mission spacecraft (%) 

Cumulative average learning rate 90 

for the annual cost of operating 

the demonstration satellite (%) 

The results of the analysis are summarized in Figures 3.7 and 3.8. Figure 3.7 

indicates the salvage value (present value) of the demonstration sate!lite when the I 

demonstration satellite is used as a source of power for other space activities such 

as GE0 platforms, manufacturing bases, OTV or space exploration vehicles. The 

salvage value is shown as a function of the annual demand for space power and the 

cost of earth to GE0 transportation. It can be seen that the salvage value is not 

materially impacted by transportation costs but is directly related to demand 

(MW/yr). At very high demand levels the salvage value can approach $150 - 

170 million and at a demand level of less than 1.5 MW/yr the salvage value is zero. 

It is possible that other major (nonpower) subsystems such as sliprings, mechanisms, transmitter subarray and switchgear and converters will be 

salvageable for other space missions. Figure 3.8 illustrates the salvage value of 

the SPS demonstration satellite when the power supply and several other major 

subsystems are salvageable. The salvage value is shown as a function of annual 

demand for power, the cost of earth-GE0 transportation and the time (relative to 

2000) at which the nonpower subsystems are salvaged.* Salvage value may 

approach $400 million when other subsystems are salvaged and the demand for 

* 

It should be noted that certain of these curves terminate abruptly. For 

example, the curves for 20 year time delay terminate at a demand of 10 

MW/yr indicating that the power subsystem would be completely segmented 

at the end of 20 years. It is assumed that other subsystems are not 

salvageable after the power supply is completely segmented. 
45 

0 5 10 15 

OOWD. )Y/YR. 

FIGURE 3.7 SALVAGE VALUE OF THE SPS DEMONSTRATION SATELLITE WHEN USED AS A 

SOURCE 0~ POWER FOR OTHER ACTIVITIES (GEO PLATFORMS, MANUFACTURING BASE, OTV OR SPACE EXPLORATION VEHICLES) ' 

---- 0 - ' TIM CtLAY (YEARS FROM 

0 

ZODO) TO SUVKif OF DH0 KMER SUBSYSTEMS 

0 

ASSIMES USE OF SLIPRINGS. 

M3ANISHS. TRANSMITTER 

SUBARRAY AJID SYlTCHGEAR 

AND CONVERTERS 

- - - 8M$/KG ECATH-GE0 

- 701/t% TRAllSPORlATIOII 

COST 

01 1 - . . 1 . A . . I . . . . I c 

0 5 10 I5 

DUIISID. WYR 

FIGURE 3.8 SALVAGE VALUE OF SPS DEMONSTRATION SATELLITE WHEN USED AS A 

SOURCE OF POWER AND OTHER SUBSYSTEMS FOR OTHER ACTIVITIES 

(GEO PLATFORMS, MANUFACTURING BASE, OTV 0~ SPACE EXPLORATION 

VEHICLES) 
46 

power is high. Salvage value may approach as much as $200 million when other 

subsystems are salvaged and the demand for power is low. 

3.3 Power Supply for a Laser Orbit-to-Orbit Transportation System 

Table 2.1 shows that whether or not the SPS program moves into an 

implementation phase, there is likely to be a substantial level of LEO to CEO 

traffic. A considerable fraction of this traffic will include man and logistics and 

must be transported relatively quickly, thus prohibiting the use of low thrust, 

electrically propelled orbit transfer vehicles. The presently planned mode for 

providing LEO to CEO transportation of personnel and logistics is to use a chemical 

rocket personnel orbit transfer vehicle (POTV). As Table 2.1 shows, the propellant 

requirements for the chemical POTV are considerable. These propellants must be 

transported from earth to LEO. The implementation of a laser space transportation system with a specific impulse of 2,000 s could reduce the propellant mass 

requirements by about 72 percent.* 

Assuming that propellant costs remain constant, and that the POTV capital 

cost and per flight maintenance costs are approximately equal for both the 

chemical and laser configurations, the principal benefit attributable to a laser 

space transportation system will be derived by means of cost savings in earth to 

LEO transportation of propellants. Furthermore, it is likely that the cost of 

transportation from earth to LEO will depend upon whether or not the SPS program 

proceeds into an implementation phase. Since transportation costs are a major 

fraction of total SPS capital costs, the transportation costs are likely to be low if 

forced by SPS technology development. They are likely to be significantly higher if 

SPS is not implemented thus alleviating much of the need to achieve low 

* 

Laser Rocket System Analysis, Final Report, Lockheed Missiles and Space 

Company, Inc., NASA CR-159521, September 1978. 
47 

transportation costs. At the same time, the demand placed upon a laser space 

transportation system will be very much higher if the SPS program proceeds into an 

implementation phase than if it does not. Thus the fact that the SPS program is 

likely to result in technologies leading to reduced launch costs, and thus to reduce 

benefits for a laser space transportation system, is substantially offset by the 

increased traffic that implementation of the SPS would cause. Accordingly the 

benefits of a laser space transportation system are evaluated using as a baseline 

the LEO to CEO POTV traffic model identified in Table 2.1. Earth to LEO 

transportation costs are assumed to be $70 per kg. A second case is also 

considered using an earth to LEO transportation cost of $800 per kg representative 

of an advanced Space Shuttle or Shuttle derivative vehicle. 

To compute a salvage value for this use it is necessary to determine year-byyear savings achieved by the laser space transportation system. To obtain a LEO 

to GE0 traffic model year by year during the period 2000 to 2030, it is assumed 

that the lower bound of the transportation requirements given in Table 2.1 apply to 

the year 2000 and the upper bound apply to the year 2030, and that traffic growth 

between these years is linear as shown in Figure 3.9. The present value of savings 

obtained by this traffic model, at a 4 percent discount rate, is equal to 83.8 times 

the year 2000 savings. 

The present value of the demonstration satellite in this use for the baseline 

case with transportation costs of $70 per kg is $1.68 billion, and at $800 per kg 

transportation costs to LEO is $19.27 billion. These numbers, of course, are likely 

to apply if the SPS program does not proceed into an implementation phase. If the 

.SPS program proceeds into an implementation phase, the benefit from this salvage 

value would be very much larger. Thus it is clear that it is desirable to devleop and 

implement the laser space transportation system independent of the SPS program. 
48 

0 I 

2000 2030 

FIGURE 3.9 LEO TO GE0 TRAFFIC GROWTH 

Since the laser SPS configuration is presently under consideration, it would 

appear an interesting option to include a laser power transmitter on the demonstration satellite such that demonstration tests for both the microwave and laser SPS 

configurations could be performed with the demonstration satellite and such that, 

upon completion of these tests, the satellite could be easily converted to use as a 

power supply and laser power transmitter for a laser space transportation system. 

These arguments are reinforced by the fact that the benefits of a laser space 

transportation system are of sufficient magnitude to warrant its development even 

if an SPS demonstration satellite is not constructed. 

Since the benefits of a laser space transportation system are likely to exceed 

the costs of the SPS demonstration, the salvage value of the demonstration 

satellite in this use is equal to the present value of a power supply for a laser space 

transportation system, discounted from the initial date of operation of the laser 

space transportation System to the initial operation date of the SPS demonstratjon 

satellite. If this time period is very short, the salvage value of the demonstration 

satellite becomes approximately equal to the cost of the demonstration program 

less the cost of the microwave transmitting antenna and associated systems. These 

equipments, however, could be salvaged for use on the first full-scale SPS satellite, 
49 

provided that the program enters an implementation phase. 

3.4 Source of Space-Based Materials 

A potential use of the SPS demonstration satellite is as a source of materials 

conveniently located in geosynchronous orbit. In this salvage use the demonstration satellite would be cut up into small sections, possibly melted down and 

reused as raw materials for space-based manufacturing processes. This salvage use 

is considered in more detail in Section 4.6 relative to full-scale SPS satellites. It is 

found that the value of the raw materials which make up the demonstration 

satellite is relatively small, roughly on the order of $157 million. The fact that 

these materials are located in geosynchronous orbit, however, adds an incremental 

value of about $50 million (at SPS transportation costs, 50,08O$/MT), bringing their 

on-orbit value up to approximately $217 million. Unfortunately not all of the 

materials contained in the demonstration satellite would be salvageable. The 

majoi items in question include sapphire and GaAs. These materials alone 

constitute about 63 percent of the total on-orbit value. Thus if they are not 

salvageable, the on-orbit value of the SPS materials decreases to about $81 million. 

Even so, much of this value is made up of materials which are not likely to be 

easily salvaged for use as raw materials in manufacturing processes. 

Because of the relatively low value that the demonstration satellite has as a 

source of raw materials in space, this is not a very desirable salvage option. 

Furthermore, the return of these materials to earth for reuse would, in all 

likelihood, cost substantially more than their value on earth. 
50 

4. FULL-SCALE SPS SATELLITE SALVAGE ALTERNATIVES 

Starting in the year 2001 and continuing through the year 2030, two full-scale’ 

SPS satellites will become operational each year in addition to a full-scale SPS 

satellite becomming operational in the year 2000. The full-scale satellite 

characteristics are summarized in Tables 1.1 and 3.2. Current plans call for these 

satellites remaining in operation for a period of 30 years at which time they will be 

taken out of service. When this occurs it is likely that major portions of the fullscale satellites will prove useful in other space activities. The full-scale SPS 

satellites will thus have a salvage value that is related to their value when used in 

other space activities. The salvage value, as measured by costs that will be 

foregone because of the use of full-scale SPS satellites, will derive from the use of 

the full-scale satellites: 

1. In a continuing SPS program (termed “SPS reuse”) 

2. As a source of power for non-SPS space activities 

3. As a power supply for a laser orbit-to-orbit transportation system 

4. As a power supply for laser propelled aircraft 

5. As a source of power for accomplishing asteroid capture and mining 

6. As a source of space-based materials. 

These potential uses and the derived salvage value of the full-scale satellites are 

discussed in the following paragraphs. 

4.1 Salvage for SPS Reuse 

The full-scale operational satellite consists of a power generation system 

utilizing gallium aluminum arsenide (CaAlAs) solar cells with a concentration ratio 

of two; an attitude control/station keeping system utilizing argon ion thrusters; a 
51 

power distribution system consisting of switchgear and converters; conductors and 

insulation; structure; a microwave power transmission system including waveguides 

and klystrons for converting DC to RF energy; a structure system comprised of 

aluminum and graphite fiber reinforced thermal plastic and an information 

management system. The components, subsystems and systems are designed such 

that 5 GW of power are delivered at the utility interface. To accomplish this in an 

economic manner, certain systems are designed to achieve a life of 30 years (for 

example, the graphite structure), whereas other systems may achieve shorter 

useful lives and must be maintained and/or replaced periodically during the 30 year 

life of the full-scale satellite (for example, the klystrons will be replaced at ten 

year intervals). It is obvious that such a complex system will not completely 

deteriorate instantaneously at the end of 30 years but will continue to function in a 

degrading fashion for some time beyond its design life. Thus certain systems may 

be salvageable for use in other full-scale SPS operational satellites or a full-scale 

satellite may continue to be utilized beyond its 30 year nominal life. The actual 

life, including specific maintenance/replacement policies, will be determined as a 

result of the overall system economics, evolving design and design philosophy, and 

operational procedures all of which have been considered in insufficient detail at 

this time to specifically establish which components/subsystem/system maintenance/repair procedures and policies* will be accomplished and which components/subsystems/systems will be economically salvageable. 

+ 

It should be noted that these policies and procedures will be a function of 

technology and improvements in reliability. For example, if klystrons have a 

ten-year life, then they will be replaced twice and have little salvage value 

at the end of 30 years. If, however, klystrons achieve a 14-year life, the SPS 

satellite may have a 28-year life with one klystron replacement, or it may 

have a 30-year life with economically salvageable klystrons (for other SPS 

satellites). 
52 

The salvage value of reuse of components of a, full-scale SPS satellite 

depends upon which specific components, subsystems and systems are available for 

reuse at the end of the 30-year life of the satellite. To determine specifically 

which l’piecesVV will be available requires a detailed reliability/replacement/repair 

analysis which has not yet been accomplished. 

In the absence of such an analysis only a rough estimate of value may be 

accomplished by considering the value of extending the useful life of a full-scale 

satellite. The value of extending the useful life may be established as the 

difference in the present value of the cost of a series of full-scale satellites which 

become operational at 30-year intervals and the present value of the cost of a 

series of full-scale satellites which become operational at 30 + AT year intervals. 

With a real discount rate of 4 percent, a one year (AT = 1) increase in life 

corresponds to a salvage value of 2-3 percent of the satellite cost. This increases 

to 17 percent of the satellite cost when AT = 10 years. 

4.2 Power Supply for Non-SPS Space Activities 

In the same manner that the demonstration SPS satellite was viewed as a 

potential source of power (335 MW) for other space activities, so may the full-scale 

satellite be considered as a potential source’ of power (9.52 CW) for other space 

activities. The salvage value will depend upon the demand for power created by 

other space activities. The supply of power will be incremented by up to 19 GW 

per year, starting in the year 2030, and decremented by the rate of degradation of 

the power supplies. Since a mission model for non-SPS activities cannot be 

established for the mid-21st century, it is not reasonable to compare supply and 

demand (as was done for the demonstration SPS satellite--see Section 3.2) to 

establish the salvage value in terms of the demand for space power satisfied by the 

SPS satelites. It is likely, however, that the supply will far exceed the demand. At 
53 

an annual (new capacity) demand growth of 15 MW/yr, a maximum of 450 MW will 

be supplied by an SPS satellite if it lasts 30 years beyond its useful life. Since this is 

but a small percentage of the.design power level of the full-scale satellite, it may 

be concluded that the salvage value derived from this use will be a small 

percentage of the cost of one full-scale SPS satellite. 

4.3 Power Supply for a -to-Orbit Transportation System 

As in the case of the demonstration satellite, an interesting potential salvage 

use of full-scale SPS satellites is as a power supply for a laser orbit-to-orbit 

transportation system. The economics of this use are quite similar to the 

demonstration satellite case; however, the full-scale satellite provides some 30 

times more power and would thus be appropriate for use with much larger and 

higher payload vehicles. The benefits of this salvage use are strongly dependent 

upon geocentric traffic in the post-2030 period. They could be considerable if 

there are massive manned activities in space, such as large manufacturing bases, 

space habitats and so on. Alternatively the benefits could be quite small if the 

traffic remains relatively small. At this point in time the only traffic that would 

clearly exist beyond that noted in Table 2.1 is the traffic necessary to support the 

construction and maintenance of the SPS fleet. This traffic, as envisioned by 

Rockwell International, would involve on the order of 150 POTV flights per year or 

one every other day. This level of traffic can be supported by a power supply 

which is on the order of hundreds of megawatts rather than gigawatts. The 

advantage of a multi-gigawatt system would be to allow higher thrust levels, 

possibly higher specific impulse and possibly to provide power for ascent from 

earth-to-LEO. Unless the earth to LEO traffic becomes a major factor, or unless 

it becomes desirable to station satellites to provide a capability for continuous or 

unconstrained thrusting, it does not appear that this salvage use will require more 
54 

than one full-scale SPS satellite. Because of the speculative nature of the benefits 

resulting from this salvage use, they are not quantified further. 

4.4 Power Supply for Laser-Propelled Aircraft 

It has been proposed by researchers at the University of Washington and 

Lockheed Missiles and Space Company that space-based lasers be used to power 

aircraft on transoceanic flights.* Conceptually, oceanic flights would be conducted by means of conventional kerosene-powered jet engines for takeoff and 

climb to altitude. Upon reaching altitude, at some point over the ocean, the 

kerosene combustors would be shut down and the aircraft provided energy from a 

laser beam originating in space. Energy in the laser beam would be intercepted by 

a laser receiver mounted on the top of the aircraft and used as thermal energy to 

power turbofan engines. Upon descent the laser power would be discontinued and 

the use of kerosene resumed. 

It seems reasonable to base projections of the demand for power by oceanic 

aircraft on the assumption that the number of oceanic flights beyond the year 2030 

is equal to the current number of oceanic flights. It is furthermore reasonable to 

assume that all aircraft in the oceanic regions at that point in time will be 

comparable to current ‘heavy aircraft such as the DC-10 and 747. Table 4.1 

summarizes the current oceanic air traffic. There are presently about 3000 

aircraft-hours spent in the oceanic sectors each day. 

The power requirements of a wide-bodied aircraft are typified by the 747 and 

DC- 10. The 747 burns an average of about 24,000 pounds per hour of fuel at cruise 

and the DC-10 17,000 pounds per hour. These numbers correspond to power levels 

of 133.6 MW thermal and 94.6 MW thermal respectively. Thus the average energy 

Hertzberg, Abraham, Kenneth Sun and Wayne Jones, Laser Aircraft, Astronautics and Aeronautics, March 1979, pp. 41-49. 
55 

TABLE 4.1 CURRENT OCEANIC AIR TRAFFIC 

REGION FLIG,HTS/DAY HRS/FLIGHT 

NORTH ATLANTIC (NAT) 500 3.5 

CENTRAL EAST PACIFIC (CEP) 120 3.5 

NORTH PACIFIC (NOPAC) 60 6.0 

CARRIBEAN 100 2.0 

SOUTH ATLANTIC 75 2.0 

SOUTH PACIFIC 10 3.0 

WEST PACIFIC 25 3.5 

TOTAL -3000 OCEANIC FLIGHT HOURS/DAY 

consumption across the day is at the rate of about 15 GW. Assuming a peak to 

average power ratio of 2, it follows that the peak energy consumption rate is about 

30 GW. Further assuming an “end-to-end” efficiency (power into the jet engine 

divided by power into the laser power transmission system) of 20 percent, 30 GW of 

thermal energy at the aircraft requires an input of 150 GW to the laser power 

transmission systems in space. Thus to service this level of traffic will require 17 

or more full-scale SPS satellites, depending upon the extent to which they have 

degraded at the time of salvage. 

The next step is to consider the economics of this salvage use. Taking the 

cost of jet fuel to be $1.00 per gallon (roughly the present price paid by oceanic 

aircraft), the cost of the thermal energy derived from this fuel is 23.5 mills/kWh. 

It is this number which must be compared to the cost of SPS-supplied energy. 

Taking the oneration and maintenance cost for the SPS. in the salvage mode, to be 

$200 million per year (note that in this salvage mode it is not necessary to continue 

to refurbish the microwave power transmission system) and assuming that each 
56 

satellite is used at 50 percent of capacity (corresponding to a peak to average load 

ratio of 21, each satellite provides roughly 40.3 X 10’kWh per year. This results in a 

marginal cost of energy at the satellite bus bar of 5.0 mills/kWh. Again, using the 

20 percent conversion/transmission efficiency, the cost of laser-delivered energy is 

about 25.0 mills/kWh. Thus it appears that, at the present price of jet fuel, this 

salvage use does not have economic benefit. 

On the other hand, however, it is likely that the cost of jet fuel will continue 

to inflate at a rate which is somewhat above the level of general inflation. Thus it 

becomes interesting to consider the potential benefit of this salvage use at inflated 

jet fuel costs. If all oceanic aircraft shown in Table 4.1 made use of laser energy 

on the oceanic segment, a total 1.3 X 1011 kWh of energy would be supplied each 

year to these aircraft from SPS satellites. Taking an infinite horizon benefit 

approach and a 4 percent discount rate, this would yield a cost saving benefit of 

$3.3 billion (net present value referenced to the date at which the system is fully 

operational) per mill/kWh cost savings obtained by the use of SPS power over jet 

fuel. This breaks down to a benefit of $193 million per satellite. 

To continue the above example, if the price of jet fuel escalates to a level of 

$2 per gallon (1977 dollars), the benefit becomes $4.2 billion per satellite. 

Assuming that salvage to this use would occur at the end of the satellite% nominal 

30-year lifetime, the salvage value thus becomes this $4.2 billion amount 

discounted back to the initial operation date of the satellite (30 years). Accordingly the salvage value for this use, assuming $2 per gallon jet fuel, is $1.3 billion 

per satellite. 

It is interesting to note as an aside that this SPS satellite salvage use would 

make use of orbital positions over the ocean as opposed to over the continents and 

thus would not conflict with operational SPS satellites. 
57 

4.5 Asteroid Capture and Mining 

It has been proposed by Brian O’Leary* that Amor and Apollo asteroids could 

be captured and placed into earth orbit to provide a source of raw materials for 

various space activities. Typical characteristics of Amor and Apollo asteroids are 

shown in Table 4.2. The estimated population of these asteroids greater than 100 

m in diameter is about 150,000. They are presently being discovered at the rate of 2 

to 3 per year. The Apollo and Amor asteroids appear to be typical of ordinary and 

carbonaceous chondrites and contain a number of free metals including nickle, iron, 

gold, silver, platinum and so on. They are located in orbits close to that of the 

earth and require only about 3 km/s velocity increment for capture. 

O’Leary proposes the use of a mass driver that is capable of using asteroidial 

material to provide the necessary impulse for asteroid capture. This mode of 

capture would consume a significant fraction of the asteroid. Another mode, that 

examined here, proposes the use of argon propellant at 10,000 s specific impulse 

and the use of the SPS satellite as a power supply to effect asteroid capture. Taking 

a AV of 3 km/s each way and a 100 m diameter asteroid, 1.25 million MT, the 

propellant requirements are 2,300 MT outbound and 39,100 MT inbound for a total 

of 41,400 MT. Using this trajectory mode, a thrust duration of somewhat in excess 

of one year is required to impart the AV with the asteroid in tow. 

The economics of asteroid recovery depend strongly on the materials 

contained in the asteroid and the demand for these materials in space. Typical 

values of iron and nickle contained in a 100 m diameter asteroid are as follows: A 

10 percent yield of iron would provide 0.125 million MT with a gross value, at $210 

O’Leary, Brian, Mass Driver Retrieval of Earth-Approaching Asteroids, 

presented at the Third Princeton/AIAA Conference on Space Manufacturing 

Facilities, Princeton, NJ, May 9-12, 1977. 
58 

TABLE 4.2 CHARATERISTICS OF ACW)R AND APOLLO ASTEROIDS 

, 

l . POPULATION BY DIAMETER 

> loom -150.000 

> 5ochn - 6,000 

>lOOch 1.600~800 

DISCOVERY RATE 2-3/YR 

NUMBER OF FJUMN APDLLO/MtR ASTEROIDS 37 (AS OF 1977) 

l COMPOSITION, X (TYPICAL OF ORDINARY AND CARBONACEOUS CHONDRITES) 

SILICATES 75-90 

WATER O-20 

FREE METALS O-20 

CARBON WATERIALS o-7.5 

NITROGEN o-o.3 

FREE METALS INCLUDE NICKLE. IRON AND LESSER QUANTITIES OF GOLD. 

PLATINIB. SILVER, ETC. 

l TYPlCAL AV REQUIRED FOR CAPTURE- 3Kn/SEC 

l ASTEROID MWi BY DIAMETER 

10&n 1.25 X lo6 MT 

5oOm 150 x 105 MT 

1OOOlll 1.25 X 10' MT 

per MT for pig iron, of $26 million equivalent value on earth or $6.286 billion at 

geosynchronous orbit. A one percent yield of nickle would yield 12,500 MT with a 

gross value at $4,590 per MT of $57 million on the earth or $683 million at 

geosynchronous orbit. Beyond iron and nickle the total value of an asteroid will 

depend strongly on the quantities of rare materials which it contains. Sizeable 

deposits of silver, gold, platinum, rhodium, osmium, etc. could drive the total value 

of the asteroid up substantially. But the quantities of these materials likely to be 

found in any particular asteroid are highly uncertain at the present time. 

Conceivably, the value of a 100 m diameter asteroid in geosynchronous orbit could 

be as high as $10 billion. However, much lower values are likely, especially due to 

the fact that there would not exist an on-orbit demand for all of the metals which 

the asteroid contains. 
59 

The value of the materials contained in an asteroid located in geosynchronous 

orbit must be compared to the cost of recovering the asteroid. The cost of 

providing sufficient propellants (assuming the trajectory mode stated) ‘at geosynchronous orbit, is approximately $2.1 billion. It follows that the total cost of an 

asteroid recovery mission would be on the order of $2.5 billion to $3 billion. 

Consequently, if the net on-orbit value of the minerals recovered from the asteroid 

is on the order of $7 billion to $8 billion, the net salvage value of SPS used for an 

asteroid recovery mission would be on the order of $1 billion to $2 billion (after 

discounting). 

4.6 Source of Space-Based Materials 

If no salvage uses can be found for a particular SPS satellite, its subsystems 

or components, that satellite may nonetheless be salvaged as raw materials for use 

in space-based manufacturing processes. Table 4.3 summarizes the materials 

contained in a full-scale SPS satellite. While the total value of these materials is 

approximately $4.5 billion on the earth, most of this value is contained in the 

sapphire and CaAs which make up the solar array blanket. The major metals 

contained in the satellite have a value on earth of only $205 million. In 

geosynchronous orbit, accounting for cost of transportation, these materials would 

have a value of approximately $1 billion. Thus, depending upon the demand for 

their use in space, these materials could have reasonably significant salvage value. 

However it is unlikely that any but very special materials such as silver could be 

economically transported back to earth for terrestrial reuse. 

Two satellite materials, sapphire and CaAs, which contain over 60 percent of 

the total on-orbit value of SPS satellite materials, present an interesting salvage 

possibility. Thus if there is a demand for them and if they can be economically 

processed for reuse in space, they would be of considerable salvage value. If such 
60 

TABLE 4.3 VALUE OF SPS SATELLITE MATERIALS--GaAs. CR=2 

MSS UNIT COST VALUE VALUE AT GEO* 

MATERIAL METRIC TONS (KT) f/MT $ BILLIONS $ MILLIONS 

6FRTP 7.680 57.200 439 824 

l STAINLESS STEEL 5.305 1.370 7 273 

l COPPER 4,834 1,570 8 ,250 

b SAPPHIRE 3,376 8OD.000 2.701 i.870 

l ALWINIM 4,122 1.1.70 5 211 

b G~AS (DEP) 1,354 700,000 948 1,016 

TEFLON 1.152 6.820 8 66 

'KAPTON 2,719 66,000 179 315 

l SILVER 928 196,000 182 228 

MERCURY 89 4,500 0 4 

l TUNGSTEN 646 32.400 3 35 

HISC. 1,947 98n 

34.152 4.460 6,190 

l EARTH-TO-GE0 TRANSPORTATION COST = 50,080 f/MT 

t+ TRANSPORTATION COST ONLY 

0 SALVAGE OF KAJOR METALS--f205H ON EARTH, f997H AT GEO--COST TO RECOVER AND 

RETURN MAJOR HETALS TO EARTH-$18 ($79W FOR TRANSPORTATION ALONE) 

b SAPPHIRE AND GaAs PRESENT-AN INTERESTING SALVAGE POSSIBILITY 

- 

] 

reuse is economically viable it would probably be for the purpose of making new 

solar arrays both for new SPS satellites and for other space power requirements. 

4.7 Miscellaneous Salvage Uses 

It is likely that there will be other potential applications of decommissioned 

full-scale SPS satellites. In the mid-21st century, space industrialization will come 

into its own with the need for large space stations, high power and raw materials. 

It is also likely that there will be large laboratory facilities (for example, a high 

energy physics laboratory) in geosynchronous orbit. It is hard to establish a value 

for salvage use of SPS satellites for these activities because they do not lead to 

economic activities that can be easily evaluated. For example, salvage of an SPS 

satellite may make the establishment of a high energy physics laboratory in space 
61 

viable, but the salvage value of the SPS satellite in this use would not equal the 

cost savings afforded since the availability of the SPS satellite would.enable this 

mission, not merely benefit it. Accordingly estimates of salvage value for these 

uses would be highly speculative and are not included here. 

4.8 Continued Use 

An obvious potential use of a 30 year old SPS satellite is to simply continue 

to use it as an SPS satellite. Since the satellite would be fully depreciated at this 

time, its continued use would provide, in essence, a salvage value. The only thing 

which would prevent a satellite from obtaining salvage value from continued use 

would be if there is a wearout failure mode for the satellite which occurs shortly 

after it has been in use for 30 years. If, on the other hand, the satellite degrades 

exponentially with time at a rate 6 then the net salvage value (net of disposal costs 

at the end of its economic life) is approximately given by the following equation: 

EOr 

%= Pi% 1 

(1+/J+ a)l-f - (I+P+a)‘-T ]- CoM [ - 

P 

(I+PP - (l+p)1-T - CD (l+p)-T 

3 

where EOis the beginning-of-life energy produced by the satellite per year, r is the 

revenue generated in mills/kWh, t is system age when salvaged in years, COM is 

the annual operation and maintenance. cost, CD, is the disposal cost and P is the 

discount rate. T is the satellite age at the end of its economic life (when revenues 

equal marginal operating costs): 

T= 

ldEor/coM) 

In(l+a) 

For typical values of these parameters, Figure 4.1 shows the continued-use SPS 

salvage value. Clearly, for degradation rates between 0 and 2 percent, this salvage 

use produces a considerable salvage value at t = 30 years. It is also clear, however, 
62 

PV OF 

SALVAGE USE 

REFERENCED 

TO IOD. 

$ BILLIONS 

ASSUMES 

I 0 

.5 I \ r = 50 HILLS/kWh 

CAPi KITY FACTOR = 0.9 

I'\ 

BOL POWER = 5 GW 

C,, = $0.65 B/YR 

IR 

0 lo 20 30 40 50 60 70 80 go 100 

SYSTEM AGE WHEN SALVAGED, YRS 

FIGURE 4.1 CONTINUED USE SPS SALVAGE VALUE 

that for degradation rates approaching 5 percent, the SPS system will not have an 

economic lifetime of 30 years. Since Rockwell International projects the degradation rate to be on the order of 0.5 percent per year, the present value of continued 

use of the SPS, referenced to the initial operation date, will be in excess of $6 

billion (conditioned on the assumption that there are no sudden wearout failure 

modes). 

The notion of continued use can be expanded to verify estimates of salvage 

value obtained by direct estimation techniques, such as those employed in the 

sections above. This can be done by examining the decision to decommission an 

SPS satellite. At any point in time there are essentially five options: to continue 

operation of the satellite; to discontinue operation and dispose of the satellite; to 

discontinue operation, dispose of the satellite and replace it with a new satellite; 

to discontinue operation and salvage the satellite; or to discontinue operation, 
63 

salvage the satellite and replace it with a new satellite. This decision and the 

values associated with each alternative are shown in Figure 4.2. R refers to the 

annual revenues generated by continued use of the satellite, COM is the annual 

operation and’maintenance cost as above, CDis the cost of disposal, CR is the cost 

of replacing the satellite, Vs is the salvage value of the satellite and PV(*) refers 

to present value. It is desirable to take the choice which has the highest present 

value at the date of the decision. The resulting decision rules are shown on the 

right side of Figure 4.2. Thus it becomes apparent that if a decision is made to 

salvage the SPS satellite, its salvage value should be greater than its continued use 

value. This notion, once again, argues for relatively substantial salvage values 

associated with annual degradation rates in the range of 0 to 1 percent per year, so 

long as there exist no wearout failure modes that will occur shortly after 30 years 

of system use. 

DISPOSE L REPLACE 

CONTINUE OPERATION 

l DISPOSE IF 

R < cow - CD > vs 

l SALVAGE IF 

R<C @4 + l-g VS’ vs ’ O 

OR IF 

R c CO,,, Vs >-CD 

SALVAGE & REPUCE 

PV ( R-C,-&-CR+VS 

l REPLACE IF 

PV(R - Con) - CR > 0 

FIGURE 4.2 THE DECISION TO DECOMMISSION AN SPS SATELLITE 
64 

5. SPS SALVAGE VALUE 

5.1 SPS Demonstration Satellite Salvage Va!ue 

Section 3 developed the salvage value for the demonstration satellite that 

will result from its use as part of a full-scale operational SPS satellite, as a source 

of power for non-SPS space activities, as a power supply for a laser orbit-to-orbit 

transportation system and as a source of space-based materials. These applications of the demonstration satellite are summarized in Figure 5.1 which indicates 

their relative timing and salvage value. 

The laser orbit-to-orbit transportation system utilizes the demonstration 

satellite as a power source for a laser space transportation system. The microwave 

power transmission system is not needed in this salvage use and is thus available 

for use by the first full-scale SPS satellite. The salvage value derives primarily 

from cost savings in the cost of transporting chemical propellants from earth to 

LEO for use in LEO to GE0 transportation of personnel and logistics. The 

considerably higher specific impulse of a laser rocket permits about a 70 percent 

reduction in the mass of propellant that must be transported to LEO compared to 

chemical rockets. The value of the demonstration satellite .when used in this 

manner is in excess of $1.7 billion. 

If the demonstration program is successful, that is if it is found desirable to 

continue the SPS program beyond the demonstration phase, the demonstration 

satellite can be used as a component of the first full-scale SPS satellite. In this 

application the demonstration satellite has a salvage value of slightly less than 

$1.7 billion. 
DEKMl'RAllON SATELLITE 

APPLICATIcmS 

1. USER ORBIT-TO-ORBIT 

~AW'ORTATION SYSTEM 

2. m TU FULL-SCALE SPS 

SATELLITE 

3. SOURCE OF PCAKR FOR 

)Ioll-SPS SPACE ACTIVITES 

4. SCURCE OF SPACE-BASED 

MATERIALS 

FUN-SCALE SATELLITE 

APPllCATI~S 

1. LASER TRAJWORTATION 2/YEAR FOR UP TO 20 ACTIVE SATELLITES 

SYSTEM PLUS REPLACEMtNlS $l.JB/SATELLlTE 

2. ASTEROID CAPTURE AND 

MINING 

A A A JlB/SATELltTE 

3. POUER MD CUTERIALS ONE PER 30 YEARS 

4. PNVSICS LABORATORY 

- - -- - $O.lB 

A A 

2um ZQlO 2020 

t 

I I 

DEIW) SATELLITE 

F POMR SYSTEM 6 LASER 

MICRWAVE POYER TRANSMISSIOH 

SYSTEM USED ON FULL-SCALE SATELLITE 

A < $1.10 

2030 2040 2050 ml 

ittt 

I I 

. . . . . . (2 PER YEAR)............................ 

FULL-SCALE SPS SATELLITES 

>$l.?B 

A- - - - - - - . . . . . < $0.28 

h - - - - - . . $0.02 - $lJ.OXl 

FIGURE 5.1 SUMMARY OF DEMONSTRATION AND FULL-SCALE SATELLITE 

SALVAGE APPLICATIONS 
66 

If the demonstration program is not successful, and if it is not desirable to 

use the demonstration satellite as a power source for a laser space transportation 

system, it will be available as a source of power and subsystems for non-SPS space 

activities or as a source of space-based raw materials. Both of these applications 

of the demonstration satellite require the segmenting of the satellite and the 

utilization of the segments over extended periods of time depending upon the 

non-SPS space activities’ demands for power, subsystems and raw materials. When 

the demonstration satellite is used as a source of power and subsystems for other 

space activities, its salvage value is on the order of $0.2 billion. This value derives 

from costs (both hardware and transportation) that would be foregone by the other 

space activities because of the use of the demonstration. satellite subsystems. 

When the demonstration satellite is used as a source of raw materials, its salvage 

value is relatively small, being on the order of $0.1 billion. A large part of this 

value is the result of transportation costs that may be foregone since the materials 

are already in geosynchronous orbit. Clearly these salvage uses are less preferred 

than the former uses. 

5.2 Full-Scale SPS Satellite Salvage Value 

Section 4 developed the salvage value for a full-scale..SPS satellite relative 

to its date of initial operation. The salvage value was developed for continued use 

of the satellites in the SPS program, as a power supply for non-SPS space. 

activities, as a power supply for laser transportation (orbit-to-orbit and aircraft) systems, as a facility for asteroid capture and mining and as a source of 

space-based materials. These applications of the full-scale SPS satellites are 

summarized in Figure 5.1. The salvage value of the SPS satellites for these uses 

occur 50 to 80 years in the future. The uses which appear to be most attractive 

include laser transportation systems, both space-to-space and for aircraft on 
67 

oceanic routes, as a power supply to recover Amor and Apollo asteroids and, 

although not quantitatively evaluated, as a power supply for a high-energy, 

high-vacuum physics laboratory in space. It is conceivable that these uses, plus 

other uses such as power for space manufacturing, could provide sufficient demand 

for salvage use of an entire fleet of 60 5 GW SPS satellites. 

The relative timing of the salvage use of full-scale SPS satellites is indicated 

in Figure 5.1. The bulk of the salvageable full-scale satellites (20) will be used for 

the laser transportation system with three additional satellites used for asteroid 

capture and mining, one additional satellite used for providing power and materials 

for other space activities and two additional satellites used for high energy physics 

laboratories. The remaining 34 satellites are disposed of at a disposal cost of $100 

million ($30 million present value at the initial operation date). The salvage value 

is taken at $1.3 billion for each full-scale satellite used in the laser transportation 

system with this figure based upon infinite horizon discounting. It should be noted, 

however, that if the satellite must be replaced periodically, the replacement 

satellite does not have to be disposed of but the replaced satellite must be disposed 

of instead. Thus replacement considerations do not alter the computed average 

satellite salvage value. The salvage value associated with asteroid capture and 

mining is taken to be $1.0 billion per satellite. The maximum possible salvage 

value associated with the use of the satellite as a source of space-based materials 

is on the order of $0.3 billion for the major metals (not including nonsalvageable 

items such as sapphire and CaAs). Assuming that one-third of the available major 

metals are actually salvaged, the salvage value is on the order of $0.1 billion. 

All of the above numbers are per satellite salvage values and disposai costs, 

and are referenced to the time of initial operation of each satellite. It is desired 

next to combine all salvage uses and disposals to estimate the average salvage 
68 

value per satellite. This is accomplished by disounting the salvage value and 

disposal “cash flow” stream back to the date of initial operation of the first 

full-scale satellite yielding a present value of the net program salvage values. (A 

component of this cash flow stream is the present value of the disposal cost, of 

$0.03 billion, associated with each satellite that is not salvaged.) There are 

26 full-scale satellites that are salvaged over a 30-year period in the indicated 

scenario and 34 full-scale satellites that have to be disposed of. The present value 

of the “sal’vage value cash flow stream” (at a 4% discount rate) is approximately 

$22 billion. An equivalent annuity may be established which over the 30-year time 

period (60 satellites) has the same present value as the salvage value cash flow 

stream. This annuity, approximately $0.64 billion per satellite or about 6 percent 

of the satellite capital cost, corresponds to the average net salvage value per 

satellite. It should be noted that this value could increase substantially if salvage 

uses are found for the 34 satellites that are disposed of in the scenario presented. 

5.3 Programmatic Implications 

There are two significant programmatic implications of positive SPS demonstration satellite and full-scale satellite salvage values. The first deals with the 

salvage value of the demonstration satellite. Although the salvage value of the 

demonstration satellite is very much smaller than the salvage value of the 

full-scale SPS satellites, it is probably a more important consideration from a 

programmatic standpoint. The second programmatic implication deals with the 

effects of salvage value upon the cost of SPS-generated electricity and hence on 

the perceived benefits that development of the SPS concept would provide. 

The implications of the demonstration satellite salvage value are shown in 

Figure 5.2. In advance of performing the demonstration research phase, it cannot 

be known that this effort will be successful; that is, that upon completion of the 
69 

DEMO COHIERC IALI ZAT ION 

cD BsPs 

(a) PROGRAM DECISION TREE WITHOUT SALVAGE 

PRE-DEMO 

PHASES 

,'P/D 

LASER TRANS. SYS. 

LTS - 'P/D - cD) 

(BLTS + BSPS - CP/D - CD) 

PRE-DEMO DEf10 COMMERCIAL I ZAT ION 

PHASES + LASER TRANS. SYS. 

'P/D cD BSPS' BLTS 

(b) PROGRAM DECISION TREE WITH SALVAGE 

FIGURE 5.2 PROGRAMMATIC IMPLICATION OF DEMONSTRATION SATELLITE 

SALVAGE VALUE 

demonstration phase it will be decided to commercialize or implement the SPS 

technology. Thus two options may be considered to exist upon completion of the 

demonstration phase. These are termination of the SPS program and commercialization or continuation of the SPS program into an implementation phase. The 

consequences of a termination or stop decision would be that the costs sunk in the 

SPS program, Cp,l, and Cl, in Figure 5.2, would be lost and the beneifts of 

commerialization, B sps, would not be realized. It is only through’the commercialization phase that the SPS development costs would in any way be recovered 

(Figure 5.2(a)). 

On the other hand if the demonstration satellite can be salvaged say, for 

example, for use as a power supply for a laser space transportation system, this 

salvage use provides a benefit, BLTS in Figure 5.2(b), that directly offsets the SPS 
70 

development costs, even in the event that the SPS program does not continue into 

an implementation phase. This effect becomes very dramatic when one reaches 

the decision to proceed with the demonstration phase. At this point the net cost of 

the demonstration is CT., - BLTS rather than CD. The difference which the term 

BLTS makes in the decision to pursue the SPS concept through the demonstration 

phase is profound indeed, especially as the magnitude of BLTS is on the order of 

80 percent of the magnitude of CD. 

Finally, the salvage value of full-scale SPS satellites can have a strong 

impact on the perceived benefits of development of the SPS concept. For example, 

assume that without salvage the levelized cost of power from an SPS is 

50 mills/kWh. Assume also that the cost of power from alternative energy sources 

is 55 mills/kWh. One would then perceive that a cost savings benefit to society 

would obtain from the use of SPS-generated energy versus alternative sources with 

a magnitude of 5 mills/kWh. 

If, however, the SPS has a salvage value equal to 10 percent of its capital 

cost, this salvage value will reduce the levelized generation costs for the SPS 

system by about 5 percent, resulting in a net 50 percent increase in the perceived 

benefit of the SPS. Although it may not be prudent from the point of view of a 

regulated utility to reduce its energy rates in accordance with the expected 

salvage value for SPS, incorporation of this value in the federal government’s 

planning process is entirely appropriate. 
71 

6. SPS DISPOSAL 

The principal articles considered for disposal in this study include the SPS 

demonstration satellite and full-scale satellites. These satellites may be disposed 

of either intact or in varying states of disassembly depending upon the extent to 

which they are salvaged prior to disposal. The demonstration satellite or sections 

of it, if any, will require disposal somewhere in the time period 2000 to 2030. 

Unsalvaged full-scale SPS satellites will require disposal beyond the year 2030. 

It is important to consider disposal of SPS satellites upon completion of their 

useful life and salvage for further use due to the fact that the geosynchronous orbit 

is a limited natural resource and must be conserved for important uses. It is 

prudent in consideration of SPS life cycle costs to acknowledge costs associated 

with satellite disposal and consider them as a part of the capital investment in the 

SPS system. Although SPS differs from many electric energy systems in that there 

appear to be a number of relatively valuable salvage uses, once it has reached the 

end of its useful life there is little doubt that at least some of the SPS hardware 

will require disposal. Placing a value on SPS disposal costs is in essence a 

matter of placing a lower bound on net salvage value. The data presented in this 

section should be interpreted accordingly. 

6.1 Disposal Alternatives 

Unlike terrestrial power plants where disposal infers physical disassembly of 

the plant, structures and equipment and recovery of land for alternative uses, 

disposal of SPS satellites may infer simple removal of those satellites from 

geosynchronous orbit to another orbit or location in space where they will not 

interfere with other space activities. A number of interesting possibilities exist. 
72 

First, however, it is worth noting that not all disposal options are clearly 

distinguishable from salvage. For example, it may be desirable to collect SPS 

satellites that have reached the end of their useful life at a repository location in 

geosynchronous or bit. This location might be co-located with a manufacturing 

base that, over an extended period of time, would make use of the SPS material. 

Disposal of SPS satellites to a common geosynchronous location is a trivial matter 

requiring only a few m/s of velocity increment and which could be accomplished 

over a period of one to a few months at very little cost. This disposal option has 

been discussed in part in Section 4.6 and is not considered further here. The major 

disposal options considered here include those shown in Table 1.3; L4 or L5, 

supra-CEO, moon, heliocentric orbit and earth reentry. 

The L4 or Lg disposal option is illustrated in Figure 6.1. There exists in a two 

body gravitational system five points at which gravitational forces and accelerations cancel each other such that an object placed at these positions remains 

stationary with respect to both of the major bodies. The five points are referred to 

as libration or Lagrangian points. Points LL, L2 and L3 are unstable in the sense 

that if the body placed there is subjected to a small perturbation from the precise 

position of the Lagrangian point, it will drift away or assume an orbit which 

diverges from the Lagrangian point. Points L4 and L5, sometimes referred to as 

the equilatoral Lagrangian points, however, are stable. That is to say if an object 

is placed near these points, it will tend to orbit stably around the Lagrangian point, 

at least for extremely long periods of time. Thus if SPS satellites were disposed 

of in these locations, one could expect that they would remain there unattended, 

essentially forever. The only qualification to this mode of disposal would be that it 

might become desirable to lash together all of the satellites located at each of 

these points in order to keep them from bumping violently into each other. Since 
73 

FIGURE 6.1 LAGRANGIAN POINTS IN THE EARTH-MOON SYSTEM 

L4 and L 5 are located in the orbit of the moon, the energy required to reach these 

point is essentially equal to the energy required to reach the moon. 

In tne supraGE disposal option it is envisioned that the SPS satellite would 

be removed from geosynchronous orbit to an orbit which is somewhat higher than 

geosynchronous and from which decay or perturbation resulting in interference 

witn tile geosynchronous would require a vast period of time (say greater than 

10,WO years). Orbits lower than GE0 were not considered as a viable disposal 

option because of the fact that they would result in disposed SPS satellites 

snadowillg operational SPS satellites. Any of a variety of supra-CEO orbits, 

however, are open for consideration. The orbit proposed here is two times CEO. 

This is an orbit which is substantially removed from CEO but yet one for which the 

energy requirements to reach it are modest. 
74 

The third option is considered as a means for removing the SPS satellite 

permanently from space. In this option the satellite is impacted on the lunar 

surface. Naturally any such impact would have to be carefully coordinated with 

lunar activities at the time of impact. Although it might be possible to recover 

some of the SPS materials after impact, this is not accepted as a realistic benefit 

of this mode of disposal at this time. 

The fourth disposal option considered is removal of SPS satellites to a 

heliocentric orbit such as 0.8 AU. This option removes the SPS satellites 

sufficiently far from the earth that they are effectively gone forever. The energy 

requirement for this mode of disposal is, of course, dependent upon the heliocentric 

orbit into which the satellite is placed. 

The final disposal option considered is earth reentry. This disposal option 

arouses some amount of interest because of the possibility of recovering some SPS 

materials for reuse on earth if the reentry can be sufficiently wellcontrolled. 

Unfortunately, however, this mode of disposal not only requires the highest energy 

increment and is, thus, the most expensive disposal option, it probably is not 

acceptable due to environmental and risk considerations, especially in light of the 

absurd extent to which the Skylab reentry risks were escalated in the media. 

Within each of the above disposal options there exists several suboptions. 

The principal suboptions include the trajectory mode and thrust level for the 

disposal mission. It is envisioned that the disposal would occur using argon 

thrusters at a 10,000 s specific impulse. Disposal could be by means of the last 

flight of a COTV. The COTV could use its own power supply or it could be 

augmented by power provided from the SPS satellite. In the event that it uses its 

own power, the SPS satellite could be disposed of in varying states of salvage 

incuding one in which essentially all of the solar arrays have been removed. In the 
75 

event that the satellites are disposed intact, power from the SPS satellite can be 

used and propellant tankage, controls and thrusters from the COTV could be placed 

on the SPS satellite to provide the necessary thrust and control. In this mode it ii 

likely that one would choose to use equipment that was essentially at the end of its 

useful life and was salvaged from a COTV. 

The Rockwell International cargo orbit transfer vehicle is referred to in their 

study* as an electric orbit transfer vehicle (EOTV), Figure 6.2. It has a dry mass of 

1,000 MT and carries 670 MT of propellant. This amount of propellant is sufficient 

to impart a velocity increment of 1.9 km/s to the SPS satellite. Thus, for the 

higher energy disposal option, additional propellant tankage will be required. The 

Rockwell International EOTV configuration includes 144 thrusters of which 20 percent are spares. The present specification on these thrusters is a lifetime of 

8,000 hours. This is not sufficient to complete a disposal mission that requires 

more than 333 days of thrusting time. Thus, for some dispsal options, longer 

lifetime thrusters or additional spares may be necessary. An alternative to the use 

of the EOTV thrusters is the use of the attitude control and stationkeeping 

thrusters of the SPS satellite. Sixteen thrusters are located on each corner of the 

SPS satellite making a total of 64 thrusters. These thrusters provide a total thrust 

of 832 newtons at a specific impulse of 13,000 s. Combined, these thrusters can 

impart an acceleration of about 23 x 10 -6 2 m/s to the SPS satellite. At this 

acceleration it requires 503 days to obtain a velocity increment of 1 km/s. At this 

rate it would require several years to dispose of an SPS satellite by means of the 

disposal options presented. However, with augmentation from the EOTV thrusters, 

this period of time is dramatically reduced. 

*Satellite Power Systems (SPS) Concept Definition Study, Final Report, Vol. I, 

Executive Summary, Rockwell International Report No. SSD-79-0010- 1, 

March 1979. 
76 

carv~Wvrt.-ldK0 

,,..‘wnw.-WXldno 

PAVLOMWL-S.YXIdUi 

1 h2. 

1 II 

* 

FIGURE 6.2 EOTV CONFIGURATION 

The use of very low thrusts also raises an issue as to specifically which 

trajectory mode should be used. Due to the very low thrust levels and long 

thrusting periods required of electrically propelled vehicles, the trajectory mode 

selected for their use generally entails continuous thrusting in geosynchronous 

space, resulting in spiral trajectories as those shown in Figure 6.3(a). The velocity 

increment for such a trajectory is approximately twice that of the optimal, high 

thrust or impulsive trajectory mode. By lengthening the mission timing, however, 

as shown in Figure 6.3(b), thrusting only in the vicinity of periapse and apoapse of 

the transfer orbit, it is possible to devise trajectory modes where the velocity 

increments required of a low thrust vehicle approach that of the optimal high 

thrust transfer. Thus one cannot choose a specific velocity increment for the 

disposal options presented here as these require further analysis and cost optimiza- 
77 

THRUST ARC 

(NO COAST) 

(a) CONTINUOUS THRUST SPIRAL TRAJECTORY MODE 

COAST ARC 

\\I i \ 

\-& 

THRUST ARC- 

(b) INTERMITTENT THRUST, QUASI IMPULSIVE TRAJECTORY MODE 

FIGURE 6.3 ALTERNATIVE TRAJECTORY MODES 
78 

tion. The numbers chosen were conservatively selected at two times the velocity 

increment required for an impulsive transfer. Thus the velocity increment or AV 

numbers shown in Table 1.3, and subsequently the propellant requirements to 

provide those velocity increments, are probably somewhat higher than the amounts 

which will be ultimately decided upon. However, this overestimate in cost will be 

somewhat offset by the increase in mission operations cost due to the lengthened 

disposal mission time resulting from the cost optimization of the trajectory mode. 

6.2 Disposal Costs 

There are four principal elements of dispoal costs: 

1. The cost of modifications to the SPS satellite to ready it for the 

disposal mission. These costs include added thrusters, propellant 

tankage, controls and so on. Depending upon the state of salvage of 

the satellite, some structural modifications for adaptation of an EOTV 

may be necessary. 

2. The cost of propellants. 

3. The cost of transporting propellants to the SPS satellite in geosynchronous orbit. 

4. The cost of mission operations. 

Assuming argon to be the propellant and a specific impulse of 10,000 s, 

342 MT of propellant is required for each km/s of velocity increment imparted to a 

full-scale SPS satellite. The cost of argon is presently $240 per MT thus resulting 

in a cost of propellant of $81,960 per km/s of velocity increment imparted to the 

satellite. 

Taking the cost of cargo transportation from earth to CEO to be $50,080 per 

MT, the cost of transporting propellants to the SPS satellite in GE0 is $17,102,000 

per km/s of velocity increment imparted to the satellite. 

The cost of modifications to the SPS satellite in preparation for the disposal 

mission is obviously somewhat variable. A reasonable estimate for this cost can be 
79 

obtained from the assumption that the entire EOTV vehicle is used on its last or 

20th flight to carry out disposal missions. Thus taking one twentieth of the cost of 

an EOTV, $690 million, an estimate of $34.5 million is obtained for satellite 

modifications. 

The final cost, that of mission operations, is a time dependent cost. It is 

assumed here that the mission operations costs for the disposal mission are equal to 

mission operations costs for EOTV flights. This amount is $4.8 million per year. 

Using the EOTV thruster packs, it requires about 62 days to impart a velocity 

increment of 1 km/s to the SPS satellite. Thus the mission operations costs, 

assuming continuous thrust operation, amount to about $818,000 per kilometer per 

second of velocity increment. 

Combining the above costs leads to a velocity-dependent cost estimating 

relationship for SPS disposal cost as follows: 

Disposal cost = $(34.5 + 18.0 AV) million. 

This cost is given in 1977 dollars, comparable to the SPS cost estimates. It is the 

cost presented in Table 1.3. In order to compare these costs to the satellite capital 

investment cost, they must be discounted back to the initial operation date of the 

satellite. This discount factor is (1 + P) -L where is the discount rate and L is the 

satellite lifetime. Taking P = 0.04 and L = 30 years, (1 + P)-~ = 0.308. Thus the 

present value of disposal costs referenced to the initial operation date of the 

satellite are on the order of $30 million or 0.3 percent of the capital cost of the 

satellite. 
80 

APPENDIX A 

Supporting Data for Value of the Demonstration Satellite Used as 

a Power Source for Other Activities 

A.1 Cost of Segmenting the DemonstrationSatellite-CKWS 

The SPS demonstration satellite is constructed at LEO and then flown up to 

CEO. The construction requires 120 men in orbit for 15 months with 5-6 months 

required for blanket construction. Crews are changed every three months. It is 

thus necessary to transport 600 men to accomplish the construction. 

It is assumed that the major cost associated with segmenting the demonstration satellite is the transportation cost (Earth-CEO-Earth) for men and supplies. 

It is further assumed that the segmenting can be accomplished at CEO without 

transporting the construction facilities from LEO to CEO. The efficiency of 

segmentation will depend upon the size of the components/subsystems/systems that 

are salvaged. Since the solar blanket will be constructed in about six months it is 

assumed that a total of 240 man-trips will be required to segment the power 

supply. Therefore: 

CKWS &Transportation cost for 240 men plus supplies 

335,000 KW 

Trans. Cost = Cost from Earth to LEO + Cost from LEO to GE0 

0 Unit Cost of POTV = 63 X 106$ 

0 Design Life of POTV = 300 flights 

0 Cost per POTV Flight = .09 X 106$ 

0 No. of People/POTV Flight.= 48 

0 Number of HLLV Flights/POTV Flight = 3 

0 Unit Cost of HLLV = 611 X 106$ 

0 Design Life of HLLV = 300 flights 
I - 

81 

0 Cost per HLLV Flight = 1.25 X 106$ 

0 HLLV Load Factor = .9 I 

81900 kg 

0 HLLV Payload (to LEO) = 91000 kg 

CKWS I 

I[ 

Unit Cost of POTV ----r- Design Life of POTV + POTV Cost/flight 1 X 4~~~ne;lt 

Unit Cost of HLLV 

+ Design Life of HLLV + HLLV Cost/flight X wt X 

I 1 

no. of HLVV Flights/POTV Flight 

-I[ 1. 63X lo6 

300 

CKWS I’ 152$/kW 

A.2 Cost of Installing Segmented Demonstration Satellite Power-CKWSI 

It is assumed that since the installation will probably be accomplished at the 

time of segmentation that this cost may be somewhat less than the segmentation 

cost. It is assumed (more or less arbitrarily) that the installation cost is on the 

order of 20 percent of the segmentation cost. 

CKWSI : 30$/kW 

A.3 Jnitial M-ass of Demonstration Satellite (Just Prior to Start of Salvage)- 

~NMASS 

Extrapolated from the data presented in the Rockwell Report SPS Concept 

Def. Study, Vol. VII, March 1979, the initial mass of the demonstration satellite is 

obtained as indicated in Table 3.2 and summarized below: 

Solar Array .464X 106kg 

Antenna .683X 106kg 

Array/Antenna Interfaces .147X106k_g 

Subtotal 1.294X 106kg 

Contingency (25%) 0.324X 106kg 

Total 1.618X106kg 

INMASS = 1.618X 106kg. 
82 

A.4 Achievable Power Density of Power Systems-KGKW 

From Table 3.1-2 Rockwell Report, SPS Concept Def. Study, Vol. VII, March 

1979. 

Solar Cell and blanket & reflector mass = 7.855X106kg 

Array output to Distribution Bus (EOL) = 9520 MW. 

KGKW = 7*855X106kg = .825 kg/kU/ 

9.520X 106kW 

A.5 Cost)-CKW 

From Table B-5 Rockwell Report, SPS Concept Def. Study, Vol. VII, March 

1979. 

1.1.9.1.1 Primary Structure 

1.1.9.1.2 Secondary Structure 

335 (69.5X 9520) 

1.1.9.1.3 Concentrator 

1.1.9.1.4 Solar Blanket 

1.1.9.1.5 Switchgear h Converters 

1.1.9.1.6 Conductors & Insulation 

1.5x 106$ 

2.4X 106$ 

2.8X 106$ 

60.3X 106$ 

1.7x106$ 

1.4x 106$ 

1.1.9.1.7 ACS Hardware 

(72.5X G ) 

1.1.9.1.8 Sliprings 

335 (27-6X 9520 ) 

2.6X 106$ 

1.0x 106$ 

1.1.9.1.9 Primary StructureInterface 

1.1.9.1.10 Secondary StructureInterface 

. 

. 

1.1.9.1.23 .5x 106$ 

558.6X 106$ 
83 

CKW 5 - = l.&'X103$/kW 

335kWX103