Elysium 7

Elysium 7 was a human colony planet.

Sean Calvin intended to use his mind control machine on Elysium 7's entire population, in order to retain order and sense, but the Seventh Doctor managed to convince him not to.

Years later, after the planet was invaded by an army of androids, Calvin finally used his machine on the invaders, saving the planet. (AUDIO: Forever Fallen)