O longer-term energy crisis is much more troubling than $4 per gallon gas. It has been estimated that the value of proven crude oil reserves in nations represented by the Organization of Petroleum Exporting Countries (OPEC) at $130 per barrel exceeds the entire private net worth of the United States as defined by the U.S. Federal Reserve. Unless something is done, there will be a massive transfer of wealth from the to OPEC countries over the next 10 to 20 years.
Unfortunately, alternative energy sources – including coal, oil shale, ethanol, wind and ground-based solar – are of limited potential, very expensive, require massive energy storage systems and are harmful to the environment. However, one potential future energy source that is environmentally friendly, has essentially unlimited potential, and can be cost-competitive with any of these renewable sources is space solar power (SSP).
A space solar power system would involve large solar energy collectors in orbit around the Earth. The solar energy would be beamed to the Earth via wireless radio transmission where it would be received by antennas located near cities and other places where large amounts of power are used. The received energy would then be converted to electric power for distribution over the existing grid. Cost of electric power generation from an SSP system has been projected to be as low as 8 to 10 cents per kilowatt-hour. Over time, clean space solar power could replace a large part of the present electric power-generating capacity of the . Potential savings are huge.
Past studies of SSP identified launch cost and solar cell efficiency as two critical advances needed to make the system cost effective. Recent development of thin film and higher efficiency solar cells will reduce mass launch requirements. Today, private companies are making tremendous progress in reducing launch costs, which were a major part of previous estimates of overall SSP cost. Private companies like Space Exploration Technologies Corp. (SpaceX) and Orbital Sciences Corp. will soon develop capability for very low cost launches to the international space station (ISS) under NASA’s Commercial Orbital Transportation Services program. Reasonable extensions to their current systems to make them fully reusable would be the “enabling technology” that could make a future solar power satellite system economically practical and very attractive. Because the first operational SSP system will be a costly endeavor, a more practical start would be to conduct a demonstration test using resources already paid for and in place on the ISS.
The ISS could be used as a “construction shack” for housing astronauts while they work constructing elements of a demonstration space solar power unit. The orbital location of the ISS would permit only intermittent transmission of power to Earth but would serve as a “proof of concept” for subsequent full-scale development. Existing solar arrays on the ISS could be used to supply power for the demo project. Existing robotic manipulator arms on the ISS could be used for assembly of the large transmitting antenna. Important factors that could be examined at the ISS include assembly of large elements, conversion and wireless transmission of energy to the ground, and stability and pointing of large antennas. Such a project at the ISS would make a major contribution to the development of low cost, reliable and clean energy for the nation.
It is important to realize that no new fundamental technology will be needed to begin these developments and make meaningful progress. Today’s technologies are certainly sufficient to conduct valuable tests.
Estimated at about half of NASA’s total budget over the past 15 years, and counting direct and indirect costs, we have invested more than $100 billion in the space station and its supporting shuttle flights. We now have an unprecedented opportunity to begin to develop a huge return on that investment.
In addition to the critically important space solar power development, there are opportunities on the ISS to develop ways to make a future manned Mars mission safer, faster and more efficient. This work could include radiation protection for astronauts, recyclable water and food, ion and other advanced propulsion, electric power generation, better hygiene systems, recyclable environmental systems, in-flight repair techniques and advanced robotics, among others.
We should start a project to define a space solar power system demonstration test at the international space station. The American public would be inspired by our astronauts working in space to meet critical energy needs on Earth. I believe they would strongly support an SSP demonstration project at the space station. This near- term SSP project could help make the space program relevant to the lives of all Americans.
O. Glenn Smith, PhD, is a former manager of Science and Applications Experiments for the Space Station at NASA’s in
