For the US National Security Space Office (NSSO), it is a different aspect of space solar power that is the attraction: its possible military applications. An investigation into the feasibility of space solar power culminated in a report recommending that the US government spend $10 billion over the next 10 years to develop a small satellite capable of beaming 10 megawatts of energy to Earth. If successful, this would then entice private industry to become involved and develop the technology.
Solar-power satellites could operate within a narrow region in microwaves, allowing transmission to military bases anywhere within line of sight of the satellite. Soldiers in the field could wear a receiver antenna to absorb the microwaves and charge up tbatteries for their electronic equipment.
Beaming down power could also become a cost-effective alternative to generating electricity on some far-flung military bases where it can cost more than $1 per kilowatt-hour - about 10 times the price domestic consumers pay.
Another issue is the safety of using concentrated beams of energy. Olivier de Weck, an astronautics systems engineer at the Massachusetts Institute of Technology says: "It could be dangerous. We don't know what the effects would be on airplanes accidentally flying through such beams. And what if a malfunction caused a beam to misalign and illuminate a populated area? That's a big deal-breaker in my opinion."
A conference of space and energy specialists at the MIT are due to provide a report in the next few weeks and the recommendations are likely to be influential. If they are positive, space solar power could be back on the agenda. If not, the 40-year-old idea is likely to stay on the shelf for many more decades.
Dan Cho is a writer based in New York City
