Tom Hanks wears an Omega Speedmaster

There is a scene early in Apollo 13 (1995) where Jim Lovell lies back in a lawn chair, raises his thumb to the night sky, and blots out the Moon. Tom Hanks plays him. Lovell had already been there once, as a crewman on Apollo 8, the first flight to round the far side of the Moon, in December of 1968, and now he commands the mission that is supposed to land him on it. Fifty-six hours in, an oxygen tank explodes two hundred thousand miles from home, and the landing is gone. Lovell flew to the Moon twice and never walked on it. He is the only person who ever did.

The mission's most famous minute belongs partly to a watch. With the guidance computer shut down to save power, the crew had to make a manual engine burn of exactly fourteen seconds to correct their angle of return, too long or too short and they would skip off the atmosphere or burn up in it. Lovell flew it by hand, holding the ship against the line where day met night on the Earth in his window, while Swigert counted the seconds on an Omega Speedmaster Professional. By one account the watch was Lovell's own, handed over because it was the most recently serviced. The film recreates the moment almost exactly.

For those fourteen seconds there was no computer in the loop. There was Lovell flying by the light of the Earth, Swigert reading a wristwatch, and a margin measured in heartbeats. People like to say the Speedmaster saved Apollo 13. Closer to the truth: the watch did its one small job while the men did theirs, and the fourteen seconds came out right.