The concept of space-based solar power was introduced way back in 1968, but it’s only recently that the world has latched on to the idea. Japan is definitely getting in on the action with its latest spacey plan - a $21 billion solar-powered generator in the heavens to produce one gigawatt of energy, or enough to power 294,000 homes. The Japanese government announced the plan back in June, but there has been an important new development - Mitsubishi Electric Corp. and industrial design company IHI Corp. are now teaming up in the race to develop new technology within four years that can beam electricity back to Earth without the use of cables.