Yeah, the letters JR would have to be about 200 miles across to be seen with the naked eye. It's absurd, but this is an absurd story. And Jr is an absurd, sociopathic megalomaniac, I guess. I never actually watched the show.
Helium-3 or He-3 combined with deuterium, a hydrogen isotope, in a fusion reactor is one possibility of creating energy. Helium-3 is extremely rare on Earth but common on the moon. Russia and China have some interest in mining helium-3 on the moon in the future, so the story isn't totally absurd.
And don't think I know what I'm talking about, because I don't. I just did a little research in the interest of storytelling.