Omega watches in space exploration

The Omega Speedmaster, the legendary Moonwatch, selected by NASA for all the Apollo missionsMain article: Omega Speedmaster Professional
The selection of the Omega Speedmaster Professional Chronograph as the official watch worn by American astronauts was the subject of a famous space-race era rivalry between Omega and Bulova.

All subsequent manned NASA missions also utilized this hand wound movement wristwatch. NASA mistakenly feared that automatic-winding watches relied on gravity and so insisted that the "moon watch" be manually wound. In fact, automatic movements utilize momentum and could conceivably work better in a zero-gravity environment, since the moving parts would not be subject to gravity-induced friction.

However all the instrument panel clocks and time-keeping mechanisms in the spacecraft on those space missions were Bulova Accutrons with tuning fork movements, because at the time, NASA did not know how well a mechanical movement would work in zero gravity conditions.