This graphic depicts a space solar power experiment envisioned for the International Space Station
Credit: Space News Graphic
WASHINGTON - Advocates of using satellites to beam solar power from space to Earth hope U.S. President Barack Obama?s campaign promise to develop alternative energy sources will help resurrect NASA?s interest in the technology.
NASA has been without an official space solar power program since 2002, although a coalition of government and private industry volunteers has kept alive visions of demonstrating how the United States might one day draw energy from the sun and transmit it to Earth via microwave beams.
The volunteers were disappointed in December upon learning that NASA would not provide $55 million they had asked for to conduct a solar power beaming experiment they had devised for the International Space Station. The experiment?s designers are hoping it will get another look by the Obama administration.
The experiment entails placing a system that includes traveling wave tube amplifiers, which amplify radio frequency signals, outside the space station on the Japanese Experiment Module?s Exposed Facility. The amplifiers, donated by the U.S. Air Force Research Laboratory, would be moved to another location on the space station to draw power from the station?s solar arrays and beam them to Earth in microwave form.
Old concept, new energy
While Obama has not identified space solar power as an alternative energy source he would pursue, advocates are encouraged by his appointment of longtime space solar power proponents Alan Ladwig and George Whitesides to senior positions at NASA. These advocates note that Obama?s transition team specifically asked NASA about the space station power beaming experiment.
John Mankins, who worked at NASA for 25 years and managed the space-based solar power program, said NASA should play a part in U.S. attempts to achieve energy independence.
?I don?t see how NASA or the space program can stand aloof from these [alternative energy] efforts,? Mankins said. ?Whether or not there?s opportunity for space solar power, I think it?s premature to say.?
Mankins, who recently demonstrated for the Discovery Channel that a miniscule amount of power can be received from a 20-watt microwave beam transmitted over a distance of 92 miles (148 km), said the United States should conduct a thorough study of end-to-end systems needed for space solar power, followed by technology experiments and demonstrations. The last such systems study was done 12 years ago, he said.
The concept faces a major barrier, however, in the high cost of launching satellites large enough to transmit meaningful amounts of power to Earth, according to a white paper submitted by space solar advocate Charles Miller, president of Space Policy Consulting Inc. in Dayton, Ohio, to Obama?s transition team in November. The white paper recommends establishing a national space solar power policy, assigning a lead federal agency and an incremental research program. The white paper said the cost of space solar power could be reduced if the United States develops more-affordable access to space and applies high-volume assembly line techniques to satellite construction.
Military space power
Alternative energy advocates are not the only ones interested in space solar power beaming; the U.S. military is also eying the technology as a possible means of delivering power to remote areas of the globe. The Air Force Academy, for example, has begun building two small satellites to test the concept of transmitting solar power from space via laser technology. That demonstration is expected to produce enough power to illuminate a single one-tenth-of-a-watt light emitting diode, or LED.
Meanwhile, the space station power beaming experiment has won support from Gary Payton, undersecretary of the Air Force for space.
Following a briefing on the proposed demonstration, Payton wrote Bill Gerstenmaier, NASA?s space operations chief, to say the space agency and Pentagon should begin exploring ways to collaborate on solar power beaming experiments.
?I believe it is time for NASA and [the Defense Department] to collaborate on a project to demonstrate safe space-to-earth transmission of solar energy is possible, and scalable to a magnitude that can enhance national security interests,? Payton said in the Sept. 30 letter.
In December, however, top NASA managers directed work on the project within the U.S. space agency to stop.
Mack Henderson of Johnson Space Center in Houston, who has been NASA?s lead on the space station demonstration, announced the decision in a Dec. 11 letter to members of the group.
?It is with heavy heart that I tell you that we have been asked to terminate all NASA?s support on the [space solar power] demo activity. This direction was just received from management and I wanted to pass it along to you as soon as possible to avoid wasting any more additional work that you have most graciously been volunteering,? Henderson wrote.
One member of the group, who asked not to be identified, expressed frustration that the program was canceled before the Obama administration took office.
?This is an opportunity for NASA to be involved in not only something that involves space but also energy and environmental issues,? said one team member, who asked not to be identified. ?I think NASA management was fearful that they were going to be handed this mission.?
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