Space: 1999 is a British science-fiction television programme that ran for two series from 1975 to 1977. In the premiere episode, set in the year 1999, nuclear waste stored on the Moon's far side explodes, knocking the Moon out of orbit and sending it, and the 311 inhabitants of Moonbase Alpha, hurtling uncontrollably into space.

Space: 1999 was the final production by the partnership of Gerry and Sylvia Anderson and was, at the time, the most expensive series produced for British television, with a combined £6.8 million budget. The first series was co-produced by ITC Entertainment and Italian broadcaster RAI, while the second was produced solely by ITC.