| > Could we have giant nuclear reactors in space? We could. The usual stumbling block is how to ship fissile material upwell without the risk of a launch failure spreading highly radioactive material over several countries. > What's the power loss from beaming down power? I think it's about 10% from atmosphere alone, but you have to add losses from other components in the system, including light -> current -> RF and RF -> current legs, and I've seen estimates ranging from 15% to 40% efficiency end to end; this random article includes breakdown with estimates, that multiplies down to 37.5% efficiency end-to-end. https://www.sciencedirect.com/topics/earth-and-planetary-sci... EDIT: This system design gives 7-14% end-to-end efficiency: https://arxiv.org/pdf/2206.08373 EDIT2: Also to spell out another non-obvious aspect of beamed power, it turns out that it's not the efficiency that's the limiting factor per se, but land - you can improve efficiency by building larger rectennas, but it gets very expensive very quickly once you consider paying for land under them. |