Nature Features

Pentagon examines use of solar unit in space

Dec 2, 2007, 8:31 GMT

Washington - For decades scientists and environmentalists have advocated using the power of the sun as an alternative source to light our homes, but now the US Defence Department is putting a different twist on the concept.

A little known outfit in the Pentagon known as the National Security Space Office (NSSO) wants to develop solar arrays that can be launched into space to collect sun rays, store the power and beam it back to earth.

The concept was thought of as a cleaner source of energy that could also help put a dent in global warming, but with the crunch in the energy markets and the flow of oil to the West constantly threatened by the turmoil in the Middle East, backers of the idea believe it takes on added importance for US national security.

'As the United States makes decisions now to answer the energy challenges of the next 50 years, space-based solar power must be a part of the answer,' said Mark Hopkins, the senior vice president of the National Space Society.

The National Space Society has been urging the US government to step up funding for the initiative and has also urged private companies to begin looking at the technology that would be necessary to make the concept work.

But it remains to be seen whether companies are willing to invest in research for space-based solar power because, even if the considerable technical challenges of building and deploying a system can be overcome, profits would remain years - if not decades - away.

Hopkins acknowledges the real technical challenges space-based solar power would face, but said investment is needed now to develop clean and renewable energy.

The system would include building kilometre-sized arrays that would float in space and feed energy into a satellite that would beam it back to earth with a laser or microwave. Antennas on the ground would collect it and turn it into electricity.

One of the major challenges would be building a satellite that would have to be many times larger than the International Space Station and launching it into space. The NSSO, in a recent study, concluded that Congress should spend 10 billion dollars over the next 10 years to build a test satellite.

The Pentagon's interest in the system also has simple strategic implications. The NSSO study said fuel in Iraq is expensive and US soldiers lose their lives guarding fuel convoys. With space-based solar power US bases would simply get the energy they need from space.

'This may provide troops abroad in unfriendly or ill-equipped territory with power,' the study said.

Space-based solar power could also support humanitarian or peacekeeping missions in remote regions of the world, and could respond to areas where power has been knocked out by natural disasters, the NSSO said.

The US government first began exploring generating solar power from arrays in space in the late 1960s, but the idea was abandoned because it was thought to be too expensive and the necessary technology was not available.