> However, the biggest problem is the massive losses caused by changing laser light to electricity and back across multiple hops.
Perhaps they could eliminate this issue by designing the machine at the destination to run directly off of laser light. For example one could imagine a jet engine that swaps out a combustion chamber for a heat exchanger that a high power laser keeps at high temperature. Similarly laser light can be used for remote temperature regulation. Feed it into a photonic circuit for control and computation. Illumination is trivial. The only big power draw I can think of that would be tough to do directly is mechanical actuation.
I'd even suspect that this particular direction of applied research may turn counterproductive. We have means to efficiently transfer energy from space in a form of microwave. If we - DARPA first, then necessarily its counterparts from other countries - perfect laser-based energy transfer, it would be harder to oppose laser use for energy transfer from space - all while opening a window to the use of it as a weapon. Technological progress can' be stopped, of course, but this area seems out of order in time.
Laser satellite weaponry is already here. It wouldn't matter if DARPA undertakes this project or someone else. I think it's still a good idea, if it can deliver energy cheaper than building, maintaining, and running a ground infrastructure. It could potentially lead to greater energy security. I just imagine satellites powering individual city blocks or segments, right along with remote villages. I wonder what the radiation effect is from energy delivered by laser...
I don’t think they’ve ever hiden that they are a military research organization first and foremost. That doesn’t mean there will be no civilian applications. GPS is a case in point.
Perhaps they could eliminate this issue by designing the machine at the destination to run directly off of laser light. For example one could imagine a jet engine that swaps out a combustion chamber for a heat exchanger that a high power laser keeps at high temperature. Similarly laser light can be used for remote temperature regulation. Feed it into a photonic circuit for control and computation. Illumination is trivial. The only big power draw I can think of that would be tough to do directly is mechanical actuation.