Pentagon in orbital solar power plan for world peace

Everyone knows that the US military is massively involved in American energy supplies. The deal is often said to be one of swapping blood for oil, though if it's just American blood we're on about the exchange rate is pretty good. Perhaps it would be more accurate to say that - overall - America swaps assorted explosives for oil.

Whatever. All that could change, at least in a sense, if some of the Pentagon's top thinkers get their way. Not only has the head of the US Air Force lately proposed that American warplanes should be fuelled on mushroom fuel: a new military plan has now come out advocating the use of solar powerplants in space to promote world peace. (And no, this isn't peace through superior firepower, or a desert called peace or any of those kinds of ironic military peace. It's peaceful peace where everyone gets cheap clean 'leccy.)

The new analysis (pdf), just out, comes from the National Security Space Office. It says that America should sink $10bn into building an orbiting solar power plant which would beam its juice down to the ground in the form of a high-energy microwave beam, which would hit a receiving antenna - "rectenna" - complex on the surface, and so get turned into electricity.

This is actually a fairly old idea, and has been pushed occasionally by various space advocates since the 1960s. Lovers of space-based solar power (SBSP) point out that many of the disadvantages of terrestrial solar are done away with. There are no cloudy days or even any atmosphere in space: thus solar power becomes consistent and dependable, potentially needing no backup capacity for night time or bad weather. SBSP also offers much more power for a given area of cells, about five times as much on average.

The ability to beam power down to wherever a rectenna can be erected could be useful, too, reducing earthly power transmission issues. The Pentagon particularly like this, as they often have to generate electricity in remote regions where there isn't any reliable grid to draw from. They frequently wind up paying top dollar for juice as a result, and having to drive convoys of tanker lorries full of generator fuel past grumpy, heavily-armed locals.

The space energy, too, would be green, clean and - in the present state of world space capability, anyway - free from the need to bargain for resources with dubious foreign despots.

On the minus side, SBSP platforms would be an order of magnitude bigger than anything yet constructed in space, and would require a similarly massive increase in space transport and infrastructure, and a serious drop in launch costs.

The Pentagon planners reckon that SBSP might be of some use for purely military or disaster-relief purposes. However, in order to accomplish their grander goals - clean, secure, affordable energy for the United States, world peace, etc. - a new generation of launch technology will be needed.

"In addition to the currently insufficient and extremely expensive launch fleet," the report says, "another issue is that most launches to Space today are on [Throwaway rockets]. Expendable vehicles will not support the business case for SBSP. Reusable Launch Vehicles [RLVs] will... Development of RLVs has likely been hindered by the lack of a sufficiently large market (payloads) thus far. Together, RLV and SBSP development can make one another viable."

The SBSP chaps seem to favour Two-Stage-to-Orbit, rocket powered fully re-usable launchers: essentially two rocketplanes stacked, the payload carrying one getting an initial piggyback ride from the other. They say this would involve very little in the way of new technology.

The study, says the Office, "was compiled through an innovative and collaborative approach that relied heavily upon voluntary internet discussions by more than 170 academic, scientific, technical, legal, and business experts around the world".