1 November 2007
Opinion - Power (Good)
Department of Defense Feasibility Study
Fate makes strange bedfellows
by Patrick Collins
by Dr. Patrick Collins

A recent report by the Department of Defense's National Security Space Office (DoD's NSSO), which recognises that space-based solar power has great potential and urges the US federal government to grant it $1 billion/year over 10 years, has stirred up much comment, such as in Avaiation Week and New Scientist and also on Slashdot . (As always on Slash-
Dot, readers respond with dozens of questions and answers, so you can read a good survey of ideas pro and con delivering solar power from space to Earth using microwaves or other means.)

The sad thing about the subject of SPS is that it has been exhaustively investigated numerous times...and the results are always the same. Yes, technically the system is feasible. Yes, environmentally it would probably be very beneficial as a potentially massive source of CO2-free electricity. But it could only be economically reasonable if launch costs are reduced greatly - to about 1% of what they are today.

What is perhaps surprising is that launch costs have not fallen at all over the last 50 years, because space agencies have spent the $1 trillion they received from taxpayers on anything except making it cheaper to get to space. The Soyuz rocket is still the cheapest way to travel to space - as it has been for 50 years. Recent work is generating mountains of evidence that large-scale space travel could reduce costs by 99% or more, and space tourism and solar power from space ( SPS), are seen as complementary in this (as discussed in a 1997 paper by Professor Nagatomo).

In the 1990s, DoD did a great service by paying for the highly successful, very low-cost, reusable rocket, the DC-X - which NASA then cancelled as soon as it got its hands on it. So it's like deja vu all over again to see that DoD may now do what NASA has refused to do since the 1970s - namely build a prototype SPS to test the system's potential.

Of course DoD will build something that is not optimal for the electricity industry. Professor Nagatomo's proposal for that was the "SPS 2000" Project, which remains much the largest ever study of an SPS demonstration system (involving hundreds of papers published by researchers in 20 countries). But if DoD demonstrates delivery of several Megawatts of microwave power from space to a rectenna on Earth, this may be enough to get the electricity industry involved - and they have trillions of dollars of assets and revenues. Once they believe in SPS and get to want it, we'll have it.

Funny to think that DoD may thereby find themselves obliged to develop low-cost launch once again by building another DC-X to take up where Nasa scrapped the last one! That too would probably be a good thing, in view of the burgeoning commercial demand for passenger travel, which would be sure to run with an orbital vehicle if the DoD could just pay for a prototype - the step which investors really hate to pay for, since it's still so far from any prospect of a real profit.

Fate makes strange bed-fellows. But the true objective of DoD is of course defence. Genuine defence - working to maintain peaceful global development, not military domination - is entirely praiseworthy. DoD's recent work identifying the potential of SPS to contribute to world peace could be just what is needed to get space policy investing in economically valuable activities. Let's hope they can get a serious budget.
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Patrick Collins 1 November 2007
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