Statement of
John C. Mankins

Manager,
Advanced Concepts Studies

Office of
Space Flight

Before the

Subcommittee
on Space and Aeronautics

Committee on
Science

U.S. House of
Representatives

September 7, 2000

Mr. Chairman and Members of
the Subcommittee,

I am pleased to have the
opportunity to speak with you today concerning the topic of space solar
power. During the past 5 years, NASA
has examined the viability of large-scale space solar power (SSP) systems
through a series of studies and preliminary technology research
activities.

Very briefly, our results
and findings to date can be summarized as follows:

  • Large-scale SSP is a very
    complex integrated system of systems that requires numerous significant
    advances in current technology and capabilities

  • A technology roadmap has
    been developed that lays out potential paths for achieving all needed advances
    – albeit over several decades

  • Ongoing and recent
    technology advances have narrowed many of the technology gaps, but major
    technical, regulatory and conceptual hurdles continue to exist

  • This NASA-funded SSP
    activity has made significant contributions to narrowing the technology gap
    (e.g. a three-fold reduction in mass at the solar array level over current
    state-of-the-art)

  • An incremental and
    evolutionary approach to developing needed technologies and systems has been
    defined, with significant and broadly applicable advances with each increment

  • The technologies and systems
    needed for SPS have highly leveraged applicability to needs in space science,
    robotic and human exploration, and the development of space

  • The decades-long time frame
    for SPS technology development is consistent with the time frame during which
    new space transportation systems, commercial space markets, etc. could advance

  • Power relay concepts appear
    technical viable using space solar power technologies, but may depend upon
    higher frequency power beaming

  • The question of ultimate
    large-scale solar power satellite economic viability remains open.

Now I would like to get into
some detail on each of these points and provide you with more information on
NASA‚s ongoing research and development efforts. First, I would like to summarize the historical context of these
efforts

Background

The idea of using sunlight
to power spacecraft – particularly using photovoltaic (PV) arrays – dates to
before the earliest days of the “space age” more than forty years ago. However, the concept of a large “solar power
satellite” (SPS) that would be placed in geostationary Earth orbit (GEO) to
collect sunlight, use it to generate an electromagnetic beam and transmit
energy to the Earth was invented by a Czech-American, Dr. Peter Glaser of
Arthur D. Little, in 1968. NASA and
industry studied this concept into the early 1970s. During the same period, a number of exploration applications of
large space power systems were identified – most notably the idea of using
large space power to electrically propel vehicles from Earth to Mars. Due to the limitations of PV array technology
at the time, however, these exploration studies tended to anticipate the use of
space nuclear power systems rather than space solar power systems.

During 1976-1980, a major
study of the SPS concept˜spurred in part by the energy crisis of the times˜was
conducted by the then-newly-created U.S. Department of Energy (DOE), with the
support of NASA. This effort, funded at
a level of more than $50M in FY 2000 dollars, resulted in a wide range of
useful research reports on many topics – but is best remembered for the “1979
SPS Reference System”. The central
feature of this concept was the creation of a large-scale power infrastructure
in space, consisting of about 60 SPS, each delivering 5 gigawatts (GW) of base
load power to the U.S. national grid (for a total delivered power of about 300
GW). However, connections to interim
applications of space solar power were tenuous and the space infrastructure
requirements were projected to be significant. The “cost-to-first-power” of the 1979 Reference System was expected to
be more than $275 billion (in FY 2000 dollars). As a result of the huge price tag, lack of evolutionary approach,
and the subsiding energy crisis in 1980-1981, all significant U.S. SPS efforts
were terminated. In a 1980 NRC report
on SSP, it recommended that the concept be re-assessed in about 10 years,
subsequent to additional technology development and maturation.

During the 1980s, technology
development in range of relevant areas continued – particularly in the area of
solar power generation of broad applicability in commercial and scientific
spacecraft. Also during the 1980s and
early 1990s, low level international interest in the SPS concept emerged,
including wireless power transmission flight experiments in Japan and other
activities in Europe and Canada. In the
U.S., activities were largely limited to generic research and to modest systems
studies of potential applications of SSP technology to space science and
exploration missions.

Recent NASA
Efforts

In 1995, NASA undertook a
reconsideration of the challenge of large-scale SSP systems. This effort, the “Fresh Look Study,” sought
to determine whether or not technology advances since the 1970s might enable
new SSP systems concepts that were more viable˜both technically and programmatically. The Fresh Look Study reviewed, revised or created some 29 SSP
system and architecture concepts (emphasizing gigawatt class power for
terrestrial markets). The general
finding of this preliminary assessment was that there did appear to be a number
of promising SSP systems concepts – distinct from those of the 1970s – that
were enabled by recent or projected advances in relevant technologies. The Fresh Look Study also concluded that the
prospects for power from space were – although still exceptionally challenging
– more viable than they had been at the end of the DOE-NASA study in 1980.

During 1998, NASA conducted
the SSP Concept Definition Study following the suggestion of the House Science
Committee. This study was a focused
1-year effort that tested the results of the previous Fresh Look Study. The 1998 effort engaged a wide range of
technologists from outside the Agency as well as within. In addition, NASA funded an independent
economic and market analysis study, led by Dr. Molly Macauley of the Washington
D.C.-based non-profit, Resources For the Future. The 1998 SSP Concept Definition Study found that SSP did appear
more viable than in the past˜results that largely validated the findings of the
“Fresh Look Study”, while invalidating some of the specific
systems/architecture concepts that had emerged from the earlier effort. A
principal product of the effort was the definition of a family of strategic
research and technology (R&T) road maps for the possible development of SSP
technologies.

Beginning in spring, 1999,
and continuing through fall, 2000, NASA has been conducting the Space Solar
Power (SSP) Exploratory Research and Technology (SERT) Program. This program,
which will be completed later this fall, has further defined new systems
concepts (including space applications), better defined the technical
challenges involved in SSP, and initiated a wide range of
competitively-selected and in-house R&T activities to test the validity of
SSP strategic research and technology road maps.

The SERT Program, led by the
NASA Marshall Space Flight Center has involved technologists from across the
U.S. Participants include eight NASA
Field Centers, as well as a number of external organizations through a diverse
family of some 31 individual, competitively-procured projects created as a result
of a 1999 NASA Research Announcement. Funded by NASA at a level of about $22M (approximately $15M in FY1999
and $7M in FY2000), SERT Program participants have included large and small
companies, other Agencies and laboratories, universities, and several
international organizations. Attachment
1 provides a summary list of SERT Program participating organizations. Overall participation by private industry
has been substantial, with significant technical contributions being made by
small business.

SSP Strategic
Research and Technology Challenges and Progress[1]

Systems Integration and
Analysis.

Effectively integrating information on scores of technology
options across a dozen systems concepts has been a major challenge for the SERT
Program. A broadly constituted Systems
Integration Working Group has operated as the “heart” of the effort to meet
this challenge. SERT systems
integration and analysis activities have provided a framework for modeling
various SSP systems concepts and included formulation of a progressive family
of “model system concept” options as stepping-stones to large-scale SSP
systems. An integrated model has been
used to capture technology metrics and systems data concerning these several
Model System Concept options and to place these into an overall economic
framework. As a part of these efforts,
a series of technical interchange meetings have been held during the course of
the SERT Program, involving both systems analysts and technologists from inside
and outside the Agency (see Appendix 1). One important result of the SERT systems integration and analysis effort
has been the identification of several new approaches that apply low-energy,
solid state lasers for wireless power transmission as an alternative to
microwave approaches.

Solar Power Generation.

During the 1995-1997 SSP
Fresh Look Study, solar power generation was identified as a major technology
research challenge. The SERT Program
has pursued several innovative solar power generation approaches at the
component and breadboard level that suggest this challenge can be met
successfully. Component level progress
from previous technology efforts has been focused and extended – resulting in
several “firsts”. For example, a linear
Fresnel lens-based concentrator solar array has been demonstrated at the panel
level in a test chamber with sunlight to voltage conversion efficiency almost
30% (about 375 watts/m2) and a power per unit mass of greater than 375 watts/kilogram. In application, this SERT-demonstrated
technology should be capable of achieving about 170 watts/kilogram – a better
than three-fold advance on the current state-of-the-art solar array (which is
about 45 watts/kilogram). Other areas
have also been pursued, including multiple-bandgap thin film solar arrays, the
so-called “rainbow” concentrator array, testing of a high voltage solar panel,
and others.

Wireless Power Transmission.

A variety of approaches to
safe and efficient wireless power transmission have been investigated,
including microwave phased arrays using magnetrons or solid state transmitters,
as well as visible light transmission using solid state lasers and associated
optics. To assure beam safety, “center-of-beam” power intensities have been
limited to the general range of 100-200 watts/m2 during the SERT Program for both microwave and visible light
transmission (corresponding to between 10% and 20% of the intensity of normal
noon time summer sunlight). Good
progress has been made and no show-stoppers have been identified – although
resolution of potential spectrum management issues associated with power
beaming applications with appropriate U.S. and international organizations
continues to be an important issue. The SERT Program has conducted an important
first-of-a-kind demonstration in a test chamber of the use of microwave power
beaming to drive an innovative woven Carbon-filament “sail” such as might
someday be used to send robotic probes beyond our solar system.

Power Management and
Distribution.

Power management and distribution continues to be a major
challenge for large-scale SSP systems. A major feature of the 1979 SPS Reference System was the presumption of
very high solar array voltages (e.g., 40,000 volts) that would largely
eliminate the requirement for massive power management for the system. The findings of the SERT Program suggest
that this feature is not technically feasible for reasons of interactions with
the space environment at these voltages and that lower voltages must be used. However, a great disparity exists between the
cost of terrestrial voltage converters (about $0.20 per watt) compared to
voltage converters in space (about $20 per watt). Studies are continuing to better understand the reasons for these
differences and to formulate affordable and effective power management and
distribution concepts for large-scale SSP systems. Also during the SERT Program, an option identified during the SSP
Fresh Look Study the use of superconducting power cabling at lower voltages has
resurfaced as one potential solution.

Structural Concepts and
Materials.

Affordable and very low mass structures are critical. Several innovative types of inflatable
structural concepts have been researched as a part of the SERT Program, including
a simple truss structure that is deployed by an inflated column. The integrated consideration of structural
concepts and materials as well as SSP system design concepts has been found to
be critical to effective progress as a result of the SERT program.

Thermal Materials and
Management.

Specific requirements for thermal materials and management have
been determined to be highly concept dependent. In general, however, simpler deployment and higher temperature
operations have been identified as important advances for various SSP systems
(e.g., to reject heat from a microwave transmitter array). The SERT Program has made good advances in
these areas with the development of an inflatable radiator concept using the
chemical Toluene as a working fluid that could operate at a higher temperature
(and hence with lower mass) than typical radiators.

Robotic Assembly,
Maintenance and Servicing.

The SERT Team found that the definition of preliminary SSP design
concepts was vital in order to guide and focus developments in robotic
assembly, maintenance and servicing. Of
particular importance is early and coordinated definition of structural
systems, interconnections and packaging. Several examples of innovative robotic “physiology” have been advanced
as a result of the SERT program, including a miniature walking manipulator
system, the anthropomorphic “robo-naut”, a highly-flexible “snake” robot, and
the new “Skyworker” mobile crane system concept.

Platform Systems.

The SERT team has determined
that essentially all advanced space platform systems technologies – including
areas such as central data systems, avionics, etc. – will be advanced
effectively through ongoing technology development efforts inside NASA, other
US Government Agencies and industry. These programs include the ongoing NASA Cross-Enterprise Technology
Program, the New Millennium Program, developments by the Defense Advanced
Research Projects Agency and others.

Ground Systems.

The interface of a beamed
power receiver into a local power grid is an important overall aspect of an
operational SPS system in the far term. Several low-level efforts have been implemented as part of the SERT
Program to examine these issues. For
example, a small case study was conducted examining the possible insertion of
SPS power into the local power market place in Vera Cruz, Mexico. Another small effort has examined possible
requirements for energy storage systems in conjunction with terrestrial market
use of power from space.

Earth-to-Orbit (ETO)
Transportation.

Affordable, large-scale Earth-to-orbit transportation is a key
capability for any substantial future activities relating to the exploration
and development of space, including SSP systems. How low these costs must be depends entirely on the type of
future missions and markets that are contemplated. SERT results suggest that recurring launch costs in the range of
$100-$200 per kilogram of payload to low-Earth orbit are needed if SPS are to
be economically viable.[2] The current National Space Transportation
Policy as implemented in NASA‚s Integrated Space Transportation Plan and Space
Launch Initiative, provide a solid strategic and programmatic foundation for
achieving launch costs in the range that is projected to be required during the
coming 20 years.

In-Space Transportation.

Affordable and timely in-space
transportation beyond low-Earth orbit is of equal importance to ETO transport
for many exploration and development of space goals, such as SSP. There remains a significant challenge in
achieving very-low-cost, highly reliable and timely in-space transportation
beyond low-Earth orbit. SERT results
suggest that recurring in-space transportation costs in the range of $100-$200
per kilogram of payload from low-Earth orbit to geostationary-Earth orbit are
needed if SPS delivering power to terrestrial markets are to be economically
viable. Several approaches continue to
be examined as part of the Integrated Space Transportation Plan and the NASA
Aerospace Base technology program.

Environmental and Safety
Factors.

A variety of environmental considerations and safety-related
factors continue to be examined by NASA‚s SERT Program team. Topics under consideration include the
possible effects of SSP system launch, space environmental impacts on SSP
systems, and possible effects of wireless power transmission from
space-to-ground on the Earth‚s environment. Although there is no evidence of negative environmental impacts from
either microwave or visible light approaches to wireless power transmission at
the power intensities considered by NASA‚s recent SSP studies, environmental
and safety factors continue to be given careful consideration.

The [GSR1] possible environmental benefits of power from space are also being
assessed, vis-a-vis the long-term environmental impacts of other, non-solar
base-load power generation approaches, such as fossil fuels. In this vein, NASA team members participated
in a special workshop during summer 1999 at the third United Nations Conference
on the Peaceful Uses and Exploration of Outer Space (UNISPACE-III) to discuss
the possibility of power from space as a future global energy option.[3]

Space Applications Studies.

A wide range of important
potential space applications of SSP technology and systems concepts has been
identified in three important areas: space science, space exploration and
commercial development of space.

In the area of space
science, an immediate application emerges in the form of higher power, lower
cost and longer lived solar-electric power and propulsion systems. Many ambitious potential space science
mission goals – such as landing on Jupiter‚s moon, Europa, a rendezvous with
Saturn‚s rings, and others – depend upon high-performance propulsion such as
could be achieved with solar-electric power and propulsion systems in the
50-kilowatts-and-higher power class. In
the very far term, the ambitious goal of sending robotic probes beyond our
solar system – first to the Kuiper belt, then to the Oort Cloud and beyond –
will only be viable if extraordinarily
low-cost and high-performance propulsion systems can be developed. SSP technologies and system concepts˜and in
particular, wireless power transmissions–offer one important path to such
future missions.

SSP technologies are also
broadly applicable to a number of system and architecture options for the
future human and robotic [GSR2] exploration of space. For
example, advanced solar arrays could be used in low-Earth orbit for
evolutionary upgrades of the International Space Station – reducing array sizes
and reducing re-boost propellant logistics costs. Solar-electric power and propulsion systems in the 100-300
kilowatts class may be used to affordably transfer exploration systems of 10-50
metric tons from low-Earth orbit to other locations of interest in the Earth‚s
neighborhood – such as the Earth-Moon or Sun-Earth Libration points. Systems in the 1-megawatt class have been
identified as a important option for transporting large payloads of 100 metric
tons or more from low-Earth orbit to high-Earth orbit as one phase in a non-nuclear
approach to human interplanetary missions. In addition, systems in the 1-10megawatt class may enable reusable
interplanetary transports for cargo (and perhaps people). Once at a target destination – for example
in Areosynchronous Mars orbit[4]
– such interplanetary transports could also serve as “mini-SPS”, beaming
abundant and affordable power down from space to provide non-nuclear energy to
planetary or lunar surface outposts and operations.

Finally, in prospective
commercial development of space markets, several potential applications have
been identified. For example,
geostationary Earth-orbit-based communications satellites have grown
substantially in size during the past 20 years. The most recently deployed systems have approached a level of 20
kilowatts operating power. Preliminary studies suggest that – based on current
market projections – during the next 10-20 years, “mega-communications
satellites” in the 100-kilowatt class, based in geostationary Earth orbit, ,
could become economically viable. SERT studies suggest that the barriers to
such growth – principally related to launch vehicle size constraints – might be
surmounted through the application of SSP technologies and concepts. Several other potential commercial space
applications have also been identified, ranging from the concept of a “power
plug in space” – i.e., a space-to-space power beaming system – to on-board
power for future commercial space business parks.

Market Analyses and Economic
Studies.

Building on results of the 1998 SSP Concept Definition Study
independent analysis of prospective terrestrial markets for power from space,
the SERT Program is supporting an analysis of potential space markets for an
SSP-derived “power plug in space”. (Preliminary results from these analyses have been promising.) In addition, a workshop is planned that will
consider further the challenges and prospects for SSP technology-enabled
“mega-communications satellites” during the coming years.

Strategic R&T Road Map for Space Solar Power

An important planned product
of the SERT Program will be an update of the strategic research and technology
(R&T) road maps for space solar power that were originally formulated in
November 1998. The following is a brief
synopsis of that updated strategic R&T road map.

By the 2006-2007
time frame, advances in a number of technology areas important to abundant and
affordable power in space could be achieved. During this timeframe, early demonstrations of wireless power
transmission could be implemented. For example, a 100-kilometer range power
relay demonstration could test wireless power transmission using a reflector
suspended from an airship at 20-km altitude. Similarly, initial technology flight experiments could be conducted, for
example at the International Space Station, to test revolutionary solar power
generation and management technologies.

In addition, the
technologies for an initial in-space SSP platform bus in the 100-kilowatt power
class could be demonstrated at the system breadboard level.[5] Such a demonstration would be consistent
with large-scale geostationary communications satellites, solar electric power
and propulsion systems for space science and near-Earth exploration
applications, and continuing commercial development of low-Earth orbit,
including demonstration of wireless power transmission from central power
stations to other spacecraft. Also,
during this time frame, the technology could be demonstrated for a planetary or
Lunar surface “wireless power grid” in the 5-20-kilowattpower class (a.k.a.,
“MSC-2”, as explained in Footnote 5.). This prospective demonstration would be consistent with exploration
and/or initial commercial development in these locations.

By the 2011-2012 time frame,
these initial advances could be leveraged to demonstrate the technology for a 1-megawatt
class SSP platform bus, including validation of space-to-space and
space-to-surface wireless power transmission. As noted previously, once at a target destination such a system could
also serve as a “mini-SPS”, beaming power from space to provide non-nuclear
energy to planetary or lunar surface outposts and operations. Substantial demonstrations of power beaming
from ground-to-space might also be achievable during the next decade (for
example, to transmit power to an electric orbital transfer vehicle operating in
Earth orbit).

Within the next 15-20 years,
the technologies and breadboard systems for an intermediate-scale in-space SSP
platform in the 10-megawatt power class could be developed and
demonstrated. This class of concept
(a.k.a., MSC-3) is consistent with ambitious applications in space exploration,
such as interplanetary transportation systems, or in space development, such as
sub-scale SPS pilot plants or full-scale in-space power plants. If successfully developed, these
technologies could find broad applicability on Earth and in space. For example, ultra-high efficiency solar
arrays and energy storage systems (developed in cooperation with the Department
of Energy and other Agencies) would find diverse uses terrestrially and in commercial
and scientific space applications. Both
power beaming from space-to-ground for planetary or lunar surface power
(described above) as well as power relay concepts – beaming power from
Earth-to-space-to-Earth – could be demonstrated in this timeframe.

By the 2025-2035 time frame, the technologies needed for a full-scale
in-space SSP platform producing 1-2 gigawatts of power could be demonstrated at
the system prototype level. This
concept (characterized as “Model System Concept-4” in the SERT Program) is
consistent with an initial solar power satellite “pilot plant” that could
demonstrate base load power transmission for terrestrial markets. This time frame is consistent with current
plans for the development of very-low-cost Earth-to-orbit space transportation
systems (e.g., in the $100-$200 per kilogram recurring cost range).

Ultimately, in the post-2050
time frame, very-large-scale, in-space SSP platforms in the greater than
10-gigawatt power class could become viable (a.k.a., “MSC-5”). Such systems might find application in
providing very-large-scale power to terrestrial markets, for the industrial
development of space resources, or in powering [GSR3] robotic probes to near-interstellar space during the latter portion of
this century.

Overall, the updated strategic R&T road map for SSP suggests that
significant advances could be achieved during the next several decades – with
important applications in space science, exploration, commercial space and on
Earth. Major technical, regulatory and
conceptual hurdles continue to exist, nevertheless. Systematically, the
technologies that might enable future large-scale SSP systems are sufficiently
challenging that they will require several decades to mature. However, this is approximately the same time
frame during which new space transportation systems, commercial space markets,
etc. could advance. The question of
ultimate SPS economics remains open, with key issues now appearing to revolve
around the prospects for achieving “terrestrial-class” production costs for
large space systems.

Technical hurdles have been better explored and characterized as a
result of the SERT Program, and important progress has been achieved. Nevertheless, significant and highly
challenging research and technology development must be conducted successfully
across a wide range of areas in order for affordable and abundant space solar
power to be realized.

The research and development cost of the strategic research and
technology road map outlined above would be substantial. These activities have not been prioritized
against other NASA programs and funding is not included in NASA‚s FY 2001
budget request.

Power Relay
Options

Many of the
space solar power concepts and technologies that have been examined could be
applied to the development of power relay systems and/or infrastructures. However, achieving economic viability
continues to appear challenging. Early
terrestrial demonstrations, as mentioned previously, (e.g., over a
100-kilometer distance) using microwave wireless power transmission may have
applicability in specific regions.  However, using current concepts for a geostationary Earth-orbit-based
relay, a microwave wireless power transmission system is expected to be either
too large on the ground (or in space) to be viable. On the other hand, it appears possible that ground-space-ground
power relays may be viable in the case of visible light transmission concepts,
which would be smaller in size than microwave systems. Investigation of these options – which are
also useful for a number of ground-to-space and space-to-space power-beaming
applications – continues.

Near-Term
Plans

At this time, the National
Research Council, Aeronautics and Space Engineering Board is initiating an
independent assessment of the space solar power strategic research and
technology road maps. The first meeting
of the National Research Council SSP research and technology road map review
committee will be held during the week of September 11, 2000.

During the next three
months, NASA plans to complete the SERT Program as several research and
technology efforts initiated in the past year are concluded. Consideration of a
wide range of prospective applications of SSP technologies and concepts to
human/robotic exploration and development of space missions and markets is
continuing. Detailed systems analysis
and sensitivity studies are being completed, including integrated economic
analyses of various new SSP systems concepts for potential applications for
power in space and for terrestrial markets. A final report from the SERT Program should be available early in
calendar year 2001.


APPENDIX 1

Space Solar Power (SSP) Exploratory Research and
Technology (SERT) Program Participating Organizations (Selected Examples)

NASA Field Centers

  • Ames Research Center
  • Glenn Research Center
  • Goddard Space Flight Center
  • Jet Propulsion Laboratory
  • Johnson Space Center
  • Kennedy Space Center
  • Langley Research Center
  • Marshall Space Flight Center
    (SERT Program Lead Center)

Other Government
Agencies/Laboratories

  • DOE/National Renewable
    Energy Laboratory (NREL)

  • National Research Council
    (NRC) / Aeronautics and Space Engineering Board (ASEB)

  • National Science Foundation
  • USN/Naval Research
    Laboratory

  • USAF/USAF Academy

US Companies

  • Alpha Technology, Inc.
  • bd Systems
  • Bennett Optical Research,
    Inc.

  • Bekey Designs, Inc.
  • Boeing
  • ENTECH
  • Essential Research
  • Futron Corporation
  • George Kusic Company
  • Global Solar Energy, LLC
  • Hamilton Sundstrand
  • Hughes SpectroLab
  • ILC Dover
  • L‚Garde
  • Lockheed Martin Corporation
  • MagLev2000
  • Microwave Sciences, Inc.
  • PCS, Inc.
  • Power Systems Consultants,
    Inc.

  • PRIMEX Aerospace
  • Programmed Composites, Inc.
  • Rockwell Science Center
  • SAIC
  • Strategic Insight, Inc.
  • Sverdrup
  • TECSTAR
  • Texaco
  • TRW
  • United Applied Technologies
  • United Solar Systems
    Corporation

US Universities

  • Arizona State University
  • Auburn University
  • Carnegie Mellon University
  • Cornell University
  • Fisk University
  • Georgia Institute of
    Technology

  • Howard University
  • Rochester Institute of
    Technology

  • Tennessee Technological
    University

  • Texas A&M University
  • University of Alabama,
    Huntsville

  • University of California at
    Davis

  • University of California at
    San Diego

  • University of Cincinnati
  • University of Colorado
  • University of Houston
  • University of Illinois,
    Chicago

  • University of Louisiana,
    Lafayette

  • University of Texas, Austin
  • University of Southern
    California

Non-Profit Organizations

  • Aerospace Corporation
  • American Institute of
    Aeronautics and Astronautics (AIAA)

  • Ohio Aerospace Institute
    (OAI)

  • Resources For The Future
    (RFF)

  • Space Frontier Foundation
    (SFF)

  • University Space Research
    Association (USRA)

  • USRA/Lunar and Planetary
    Institute (LPI)

  • X-Prize Foundation

International Organizations

  • CNES (French Space Agency)
  • CSA (Canadian Space Agency)
  • ESA (European Space Agency)
  • Kobe University
  • NASDA (National Space
    Development Agency of Japan)

[1] Final results of the SERT
Program will be reported following the completion of the effort in fall 2000;
the data presented here should be regarded as preliminary only and may be
updated and/or revised in the SERT Final Report.

[2] This
recurring cost is roughly equivalent to a price of $200-$400 per pound.

[3] The
UNISPACE-III workshop on “Clean and Inexhaustible Power from Space” was
organized by the International Astronautical Federation (IAF) Power Committee.

[4]Areosynchronous
Mars Orbit (AMO) at an altitude of approximately 17,000 km is analogous to
Geosynchronous Earth Orbit (GEO) at an altitude of about 37,000 km.

[5] This SSP
platform bus is described as “Model System Concept – 1” (i.e., MSC-1) in the
nomenclature of the SSP Strategic R&T Road Maps under development. Other strategic R&T road maps model
system concepts are denoted similarly as “MSC-2″, MSC-3” etc.

[GSR1] Don’t
get into the global warming argument — it is a no-win quagmire.

[GSR2] Many
of these capabilities are also useful for robotic missions to the Moon,
Libration points or Mars.

[GSR3] Voyager
1 & 2 are already near interstellar space