Testimony of Ralph Nansen before House Science Committee Hearings on Solar Power Satellites

Statement of Ralph H. Nansen
President, Solar Space Industries
Before the Subcommittee on Space and Aeronautics,
United States House of Representatives Committee on Science
September 7, 2000


The concept of solar energy generated in space for our use on the earth was first proposed by Dr. Peter Glaser in 1968 and has been studied extensively since then. The technology required for its development is known and solar power satellites have the potential of delivering abundant, low cost, nonpolluting electricity to all the nations of the earth. Their development has not proceeded because of high initial development cost of a reusable heavy lift launch system and other supporting space infrastructure. The time is now right for the United States to lead the world in developing the system. Fossil fuel costs are rising as world demand is increasing while supplies are dwindling. In addition global warming highlights the need to reduce carbon emissions in the atmosphere. The development of solar power satellites can solve these problems and bring economic dominance to the nation that develops and owns the system. The government’s role in this program should be to provide leadership, seed money, and incentives for commercial development. Specifically the funding of a small scale Ground Test Program over a three year period at a funding level of $30 million a year would demonstrate to the commercial community the viability of the system. This along with tax and other incentives will bring about commercial development and the resulting benefits to the United States and the other peoples of the world.


The concept of solar power satellites was conceived by Dr. Peter Glaser in 1968, but it was made possible by the work of William Brown of Raytheon. The idea of generating electricity in space for use on the earth was treated as an unrealistic dream when it was first presented. However, a few individuals in NASA thought it ought to be investigated, so there were some low-level studies initiated to look at feasibility. They concluded the concept appeared to be technically feasible and the cost might be low enough to be competitive if the cost of space transportation could be reduced significantly.

A study of Future Space Transportation Systems conducted by Boeing for NASA concluded that transportation costs could be lowered to very low levels with the right type of reusable launch vehicles. This opened the door to further studies of the system. When the OPEC oil embargo in 1973-74 triggered an energy crisis in the United States an effort to develop alternative energy sources, including solar power satellites, became a national priority.

In the late 1970’s a broad-based Systems Definition Study was conducted under the joint auspices of DOE/NASA. The System Definition prime contractors were The Boeing Company and Rockwell International. I was the Program Manager for Boeing during this period. The studies which involved a large number of contractors and organizations concluded that solar power satellites were technically feasible and had the potential of being economically competitive. The problem was the huge cost of development and deployment of the system before producing significant revenues. There were also uncertainties on the level of technology maturity, infrastructure development, and cost estimates. As a result of these concerns, coupled with the political opposition from the nuclear industry, the government program was terminated in 1980.

Since 1980 organized activity to study or develop solar power satellites has been limited. There was no US government sponsored work until NASA initiated their „New Look Studies‰ in the mid 1990’s. Subsequently the Department of Energy abstained from any involvement. However, during this time the Japanese government and industry became interested in the concept. The Japanese updated the reference system design developed in the System Definition Studies in the late 1970’s, conducted some limited testing and proposed a low orbit 10 megawatt demonstration satellite. Their effort has been curtailed by their economic problems. Interest by other nations has persisted, but only at low levels of activity. The overwhelming initial cost of development and deployment has remained the primary obstacle. Number one on the list of cost barriers is the cost of space transportation. Solar power satellites are only economically feasible if there is low cost space transportation.

In spite of the lack of organized activity to develop solar power satellites much progress has been made. Most of the development that has occurred is in maturing technology of the subsystem elements and space infrastructure. This includes solar cells, power processors, wireless power transmission components, robotics, space habitation modules, reusable launch vehicle technology, and computational capability.

A companion program to solar power satellites was investigated which would utilize the same concept of wireless power transmission to deliver electrical power from one location on the earth to another several thousand miles away. This could be accomplished by transmitting radio frequency energy in a wireless power transmission beam to a relay satellite in geosynchronous orbit, which would reflect the energy back to a receiver on the earth called a rectenna. This concept would allow transmission of excess energy at one location on the earth to another that needs the energy without the need to construct long distance power transmission lines. This is an attractive option. It does not require the development of new space transportation systems as the relay satellite, though large in diameter to reflect the wireless power transmission beam, can be light in weight. The only active systems required on the satellite are for pointing control and station keeping.

Over the last two decades knowledge of the potential of solar power satellites to provide our world with unlimited clean energy has drifted from the public conscience. Most people are unaware of the concept today.

This testimony is being presented to provide a brief review of Solar Power Satellites, why they have not been developed, why the United States should developed them, what the situation is today, and of particular importance is the steps the United States Government can do now to speed their development.

What are Solar Power Satellites?

Solar power satellites as envisioned are large-scale power plants based in space in geosynchronous orbit. The satellites would be in the sunlight for over 99% of the year. They would only pass through the shadow of the earth for brief periods during the spring and fall equinoxes. Electric energy would be generated by vast arrays of solar cells converting sunlight to electricity. The electricity would be routed to a phased array transmitting antenna that would convert the electricity into radio frequency energy and transmit the energy in a wireless power transmission beam to an earth-based receiver. This receiver, called a rectenna, would convert the radio frequency back into DC electricity. Power processors would then convert the DC electricity to AC power for distribution on existing power grids.

The power output of each satellite studied during the System Definition Studies was 5 gigawatts (about equivalent to the output of Grand Coulee Dam). Smaller satellites are possible. However, smaller satellites still require large space transmitters which result in increased cost of the electric power delivered to the earth. One gigawatt output is probably the smallest practical size for geosynchronous orbit using radio frequency wireless power transmission.

Why have Solar Power Satellites not yet been built?

The key issues that prevented development centered around the size of the program, its cost, safety of wireless energy transmission, and international implications. These issues were compounded by the lack of the infrastructure required to support the program and insufficient validation of cost competitiveness with other sources. Also, it is a high technology space program that is outside the framework of the conservative electric utility industry.

Solar power satellites are only cost effective if implemented on a large scale. Geo-synchronous orbit must be used in order to maximize the sun exposure and maintain continuous energy availability. The transmitter size is dictated by the distance from the earth and the frequency of the power beam. The earth based rectenna also must be large to maximize capture of the beam energy. Given that the system must be implemented on a large scale, the cost of space transportation and the required space based infrastructure becomes the dominating development cost. Development cost of space transportation is driven by the need to dramatically lower the cost of space launches which can only be reduced to low enough levels by the use of fully reusable heavy lift launch vehicles which do not exist today.

The existing space transportation market has not been large enough to justify the huge development cost of a reusable heavy lift launch vehicle system. However, solar power satellites would create a large enough market if the perceived risk of their commercial viability is reduced to an acceptable level for the commercial investment community. The commercial investment community has been unwilling to invest in a long term, high cost project of this magnitude. The recent failure of the Iridium global satellite communication system has underscored the potential risks with space based commercial systems.

The concept of wireless communications is highly accepted and used the world over. The concept of transmitting power is not. The perception is that the power cannot be transmitted safely to earth.

Why Should they be Developed in the United States now?

Energy demand continues to grow as our population expands. The electronic age is totally reliant on electric power and is creating a new need for electric power. Many areas of the nation are experiencing energy shortages and significantly increased costs. United States electricity use is projected to increase by 32% in the next twenty years while worldwide electric energy use will grow by 75% in the same period. Worldwide oil production is projected to peak in the 2010 to 2015 time period with a precipitous decrease after that due to depletion of world reserves. Natural gas prices in the United States have doubled in the last year as the demand has grown for gas fired electrical generation plants.

Global warming and the need for reduction of CO2 emissions calls for the replacement of fossil fuel power plants with renewable nonpolluting energy sources. Even with increased use of today’s knowledge of renewable energy sources carbon emissions are expected to rise 62% worldwide by 2020. If we have any hope for a reversal of global warming we must dramatically reduce our use of fossil fuels.

Solar power satellite development would reduce and eventually eliminate United States dependence on foreign oil imports. They would help reduce the international trade imbalance. Electric energy from solar power satellites can be delivered to any nation on the earth. The United States could become a major energy exporter. The market for electric energy will be enormous. Most important of all is the fact that whatever nation develops and controls the next major energy source will dominate the economy of the world.

In addition there are many potential spin-offs. These include:

  • Generation of space tourism. The need to develop low cost reusable space transports to deploy solar power satellites will open space to the vast economic potential of space tourism.
  • Utilize solar power to manufacture rocket fuel on orbit from water for manned planetary missions.
  • Provide large quantities of electric power on orbit for military applications.
  • Provide large quantities of electric power to thrust vehicles into inter-planetary space.
  • Open large-scale commercial access to space. The potential of space industrial parks could become a reality.
  • Make the United States the preferred launch provider for the world.

The Situation Today

The situation is much different now than it was in 1980 when the earlier studies were terminated. In the ensuing years much has changed. Other programs have sponsored research and development of several of the enabling technologies and much of the required infrastructure has been developed. Studies have continued in several countries outside of the United States and some limited activity is sustained by individuals and companies on their own funds within the United States.

The development of terrestrial solar cells has caused the photovoltaic industry to grow from a very small specialty group of companies manufacturing expensive solar cells in laboratory quantities to an industry that is approaching maturity. Annual production is now well over a hundred megawatts and growing rapidly. Production processes have become automated and the number of different types of cells is greatly expanded. Thin film cells with efficiencies over 18% on metal film substrates and with inherent resistance to space radiation degradation will soon be in production. These cells will produce 1400 watts per kilogram of mass with a cost potential of 35 cents per watt. The decreased weight and cost will significantly reduce satellite cost and weight from earlier estimates.

Microwave oven magnetrons, manufactured by the tens of millions, have been converted into high-gain, phase-locked, amplifiers and shown they can be used to operate at high efficiency and at low noise levels in a wireless energy transmitter. Their low unit output eliminates the need for active cooling, further reducing system complexity.

Even though the Space Shuttle has not achieved its original goal of low-cost space transportation, it has proven the concept of reusability with aerodynamic reentry and landing. It and the Russian Mir Space Station are developing the knowledge base for manned operations in space. The International Space Station will greatly increase this base and is one of the key space infrastructure elements needed to develop solar power satellites.

As a result of all the developments that have taken place over the years since the 1970s it is now possible to consider another approach for solar power satellites. Most of the estimated development costs for the 1980 DOE/NASA reference design are no longer applicable. Over two-thirds of the total estimate was for infrastructure that is now being developed for other programs. Even though the low cost and large payload capabilities necessary for space transportation of a space solar power system have not yet evolved, there is progress being made through commercial launch vehicles for communication satellites and the NASA/industry X33 program. One-third of the original 1980 cost estimates was to develop and build the first full-sized 5,000 megawatts output demonstration satellite. Based on the survey of several large utilities made by Solar Space Industries in 1994, a more realistic size for the first satellite is 1,000 to 2,000 megawatts output. This is the nominal size power plant a typical utility grid can handle without major problems. It also reduces the rectenna size of the reference system and therefore dramatically increases the potential receiver site locations.

With these considerations in mind it is now possible to take a fresh look at how to go about developing solar power satellites, lay out a development schedule, and identify who should be involved and from where the necessary funds will come.

This program is different from developing other potential energy sources. No research is required to develop the energy source for solar power satellites. It already exists. The sun is a full scale, stable, long-life fusion reactor, located at a safe distance. All that is required is to design and build a conversion system that can operate in the benign environment of space. The basic technologies are all known and proven. It is primarily an engineering application task to integrate these technologies into a operational system rather than a scientific invention/research task.

An inherent feature of solar power satellites is their location in space outside the borders of any individual nation with their energy delivered to the earth by way of some form of wireless power transmission that must be compatible with other uses of the radio frequency spectrum. They must also be transported to space. Government involvement to coordinate international agreements covering frequency assignments, satellite locations, space traffic control and many other features of space operations is mandatory in order to prevent international conflicts. Solar power satellites will ultimately become part of the commercial electric utility industry and as such, that industry could be expected to shoulder the majority of the burden of development. However, the utility industry is not the only one that will benefit from the development of solar power satellites. All of the people of the world will eventually be the benefactors, through reduced atmospheric pollution and the availability of ample energy in the future. As a result it makes sense that the development of solar power satellites be accomplished through a partnership of industries and governments of all the nations that wish to participate.

What the Government Should do NOW to Initiate the Development of Solar Power Satellites

In a partnership of US government and industry it is vital that the leadership and responsibilities of the various elements be clearly defined in order to prevent chaos. There are some logical parameters to outline how this can be done. The first step is to establish a lead nation. The United States is the logical leader in this area because of the breadth of technology infrastructure and capability that already exists, as well as the magnitude of financial resources available in its industry and financial community.

The primary role of the government in this partnership will be to provide leadership and seed money to initiate the program, coordinate international agreements, support the development of high technology multi-use infrastructure, and assume the risk of buying the first operational satellite. The United States Department of Energy is the responsible government agency in the USA. They need to form a Solar Power Satellite Program Office to coordinate international cooperation and to be the focal point for other participating US agencies such as NASA, the Environmental Protection Agency, Federal Communications Commission, State Department, Department of Defense and the Department of Commerce. NASA, because of its expertise in developing space technology, will have the biggest role and is the appropriate agency to support the development of the multi-use space technology and infrastructure.

The last element of the government role should be the purchase of the first operational satellite. A government owned utility such as Bonneville Power Administration is the logical buyer of the first unit. Bonneville with more than 20,000 megawatts of generating capacity and an extensive distribution system is large enough to absorb the power from a 1,000 to 2,000 megawatt power plant. In addition, there are sites within their service area where the rectenna could be built. The cost will be repaid by the revenue generated by the satellite. The main reason a government utility should buy the first unit is so the government would accept the initial financial risk.

The other half of the partnership is industry. Industry can provide most of the developmental funding and be responsible for the design and development of the system. It is essential that the satellites and the space transportation system be developed in a commercial environment if they are to be viable commercial ventures.

The government needs to take the initial steps that will make it possible for commercial development to take place. Government agencies should not attempt to design and develop a commercial system, rather their role should be to create the opportunity and incentives to provide for commercial development. The following tasks should be initiated immediately.

1. Fund a Ground Test Program to demonstrate the satellite functions of power generation, wireless power transmission system, and integration of the energy into a utility grid on the ground. The Ground Test Program could also demonstrate the capability of the relay satellite power transmission by simply introducing a reflector into the power transmission beam. Thus the same program can demonstrate both concepts. The funding requirement for this program is very modest. A comprehensive Ground Test Program could be conducted for $30 million a year for a period of three years. Much of it could be obtained by focusing the funds that are currently being considered for the Solar Power Satellite Program on the Ground Test Program. This program would demonstrate to the commercial world the technical capability, efficiency, and subsystem costs of the power generation and wireless power transmission portion of the system. With this demonstration in hand the commercial companies would have the evidence they need to justify commercial investment in the operational system. A description of the proposed Ground Test Program is attached as Appendix A to this statement.

2. Obtain frequency allocation for worldwide wireless power transmission for operational satellite systems. This is a crucial step needed at this time as the communications industry continues to search for additional frequencies. It is imperative that wireless power transmission establish its own frequency base. This should include 2.45 and 5.8 gigahertz as the absolute minimum.

3. Implement the commercial space development tax incentives currently being considered in Congress. The Zero Gravity, Zero Tax bill is particularly important to commercial development of space.

4. Incorporate space infrastructure development and tests for solar power satellites into the plans for the International Space Station. Funding could be obtained by modifying the test and operational plans. It would give commercial purpose for the International Space Station. A candidate list of potential tests to support Solar Power Satellite development and space infrastructure development is shown in the attached Appendix B.

5. Continue technology development for reusable space transportation systems.

6. Consider the implementation of loan guarantees for commercial development of reusable space transportation systems and other required space infrastructure systems.

7. Commit to the purchase of the first operational Solar Power Satellite after the successful completion of the Ground Test Program.

Appendix A

Ground Test Program Description


Demonstrate the complete function of solar power satellites as an electric power generating system for the 21st Century and the function of an energy relay satellite. This would include verifying technology and cost viability of the system elements associated with power generation, transmission, power conversion, and integration into an electric utility grid. It would provide the required data to update the design of a full-scale solar power satellite system.

Give the electric power industry confidence in the soundness of the concept.


The concept of the Ground Test Program is to build a small scale solar cell array, (in the range of 50 to 250 kilowatts peak output); couple it to a phased array wireless power transmitter which would transmit the energy over a short distance (1 to 5 kilometers) to a receiving antenna (rectenna); that feeds the DC power output through an inverter/power controller into a commercial AC utility power grid. This is illustrated in the following figure.


Each element of the system would be designed to incorporate several different technology approaches to be tested in the complete end to end test installation. For example the array could be made up of several 20 to 50 kilowatt sub-arrays of different types of cells, each with its own wiring scheme and power controllers. The transmitting antenna could have several types of radio frequency generators or have all of one type for one test and then be modified to another type for the next test. Different control circuitry could be tested to find the best approach for beam control. Various receiving antenna designs would be tested with associated power controllers integrated into the operation to test different designs for connecting into a commercial electrical grid.

The installation would duplicate all aspects of the power generating systems for the Solar Power Satellite concept, except for the space environment, and the range and size of the energy beam. The other functions of the satellite system have similar requirements to those associated with current communication satellites, except for size and the requirement to be assembled in space. These issues can be separated from the power generation function and verified by testing done on the International Space Station and Space Shuttle.

The concept of a relay satellite would be tested by changing the pointing direction of the transmitter and installing a radio frequency reflector that would reflect the transmitted energy onto the receiver. The radio frequency reflector acts in the same way as a mirror does for light.

Appendix B

International Space Station testing to support development of Solar Power Satellites

The International Space Station is one of the key infrastructure elements needed for the development of solar power satellites. The basic technology for the power generation and transmission will be developed and validated by a Ground Test Program, but this program does not address the issues unique to the space environment. These can only be tested in space. The Space Station is ideally suit to this task. Solar Power Satellites is a commercial program that will provide very large economic returns for the investment and by using the Space Station as the in-space test base will give the Space Station a commercial base to pay for its cost of operation.

A preliminary list of the research and development tasks and tests required for the development of solar power satellites, that could utilize the unique capabilities of the International Space Station, is shown in the following:

1. Test alternative structural concepts and assembly techniques for satellite structure.

2. Evaluate capability of alternative robotic assemble concepts.

3. Test radio-frequency generators and their characteristics when operating in the space environment.

4. Assembly techniques for the wireless power transmitter structure and subarrays.

5. Wireless energy beam formation and steering in the space environment.

6. Wireless power transmission in space from point to point (short range initially).

7. Wireless power transmission from the space station to the earth using the power capability of the space station. Evaluate beam formation and steering. Determine atmospheric effects and losses, including weather effects.

8. Evaluate and test potential candidate solar cells for performance in the space environment.

9. Test candidate mounting and assembly techniques for solar cells.

10. Tests of transmitting antenna rotary joint concepts and performance in the space environment.

11. Test ion thrusters and other electric thruster concepts for the attitude and station keeping control system. Determine characteristics and performance in the space environment and their compatibility with the solar array.

Ralph H. Nansen
President, Solar Space Industries

Ralph Nansen is the founder and president of Solar Space Industries. He has been recognized as one of the key leaders in the world to develop, promote, and manage the Solar Power Satellite program since 1973. He is the author of an advocacy book for the public titled SUN POWER: The Global Solution for the Coming Energy Crisis, published by Ocean Press. Mr. Nansen has been involved in space engineering for over 40 years, primarily with The Boeing Company. He started as a designer on the Bomarc rocket/ramjet-powered missile, and in 1961 was selected to develop the initial configuration used by Boeing in their successful bid to design and build the giant first stage of the Saturn V moon rocket. In 1962 he became design manager of the Saturn S-1C fuel tanks, the first stage of the rocket that sent the Apollo astronauts to the moon.

Mr. Nansen’s final assignment on the Saturn program was as Saturn V Cost-Effectiveness Manager. After the moon landing he moved into the position of Design Manager for the Boeing Space Shuttle definition studies. In 1973 he was made manager of the Design-to-Cost Laboratory.

From 1975 to 1980, Mr. Nansen was Boeing Solar Power Satellite Program Manager and gathered together a team of engineers, scientists, and associate contractors to develop the overall concept under the auspices of the Department of Energy and NASA.

By the mid-1970s, Mr. Nansen was well known for his work in advanced space concepts and cost analysis. He was invited to present numerous papers and participate in international conferences on future space projects in Germany and Egypt. He was invited to China as a member of the first Space Technology Exchange Mission in 1979. Mr. Nansen was asked to testify before Congressional committees such as the Senate Space Subcommittee in 1976 and the House Subcommittee on Space Science in 1978 in addition to privately briefing many Congressmen. He published numerous articles on Solar Power Satellites and represented Boeing at such major space events as the first Space Shuttle launch in 1981 and the 19th Space Congress in Florida in 1982.

In 1981 and 1982 Mr. Nansen participated in the creation of the space-based ballistic missile defense system that became known as the Space Defense Initiative (SDI). In 1983 and 1984 he was a manager on a classified military program. From 1985 to 1987 Mr. Nansen was responsible for the design of a fully reusable horizontal take-off space transportation system and the structural design of Boeing’s National Aerospace Plane concept.

Mr. Nansen retired from Boeing in 1987 to cruise the oceans of the world in his sailing ketch FRAM. But in 1992, Mr. Nansen felt that the need for a new energy source was becoming imperative. As a result he elected to terminate his retirement and resume the effort to develop Solar Power Satellites. He returned to the United States and formed Solar Space Industries in 1993 and wrote the book SUN POWER which was published in 1995.

Mr. Nansen received a BS in Mechanical Engineering from Washington State University.


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