Orbital Solar Power System

Satellites powered by solar cells are nothing new, but aerospace engineers in Japan are developing a satellite that will be capable of sending that energy back to earth. In space, photovoltaic cells can generate about ten times more energy than on the ground. The experimental satellite will produce about 2 kilowatts of electricity and convert it into microwaves which are transmitted using an antenna about 6 feet (2 meters) across. Large ground-based antennas will receive the microwaves and convert them back, generating about twice as much power per unit area as current solar plants.

The 400 kg satellite will be launched into orbit using a new solid-fuel rocket (which is also currently under development) sometime in 2017. It will be designed to orbit in the ionosphere, where air is in a plasma state, raising the question of whether plasma will interfere with microwave transmission.

The technology is likely decades away from being commercially viable. It’s estimated that the cost of one satellite capable of generating the power of a single nuclear plant would be about 1 trillion yen (more than $10 billion).