Catherine Schell in Space 1999 (1975)

In 1999, Moonbase Alpha, nestled in the Lunar crater Plato, is a scientific research colony and watchdog over silos of atomic waste from Earth stored on the Moon’s far side. On September 13, 1999, magnetic energy builds to cause an explosive chain-reaction of the waste, blasting the Moon out of Earth’s orbit and off the plane of the ecliptic, out of the Solar System. The inhabitants of Moonbase Alpha are unable to return to Earth and must survive on their wandering Moon as it is displaced further into unknown space by freak space warps. Along the way, they are joined by an alien woman with the ability to change herself into any living creature at will.