4 futuristic space technologies — and when they might happen

The best place to feel the sun’s energy is in space, without clouds to block the view or an atmosphere to absorb our star's rays.

A huge array of solar panels would therefore have an unfettered view of the sun, but the tricky part of this idea concerns building such a space-based array in the first place.

We could also imagine a network of solar farms and relay satellites around the moon , beaming power via lasers to a lunar base on the surface.

Carbon nanotubes are small enough to carry 100,000 kilometers ( 62,000-mile ) length of a space elevator.

The idea is that a mission to the moon would launch to geosynchronous orbit, rendezvous with the space-line and ride it the rest of the way to a lunar base.

It would cut the amount of fuel needed to get to the lunar surface by a third ; a mission would still have to launch out of Earth gravity well, but solar powered.

Nuclear Futures Institute is working with the U.K. Space Agency and Rolls-Royce to develop a nuclear fission reactor that could fly to the moon on a future mission.

The aim for the reactor energy output would be of the order of 100300 kilowatts in combined heat and electrical power.

It would take about 80,000 years to reach the distance of Proxima Centauri .