It's a 21st-century 'space race.' The Trump administration has announced plans to send a nuclear reactor to the moon. Now, many are asking: Do they have the legal right to do that — and who owns the moon?

The first space race was about flags and footprints. Now, the new race is to build there, and doing so hinges on power.

Placing an atomic energy source on the lunar surface is “not science fiction,” experts say, but does pose technical challenges.