He lives on the International Space Station, but astronaut Chris Hadfield still has to keep Earth time. However, he can't rely on just any watch. With zero gravity and pressurized cabins, an astronaut's timepiece has to be engineered for out-of-this-world conditions.
Hadfield wears an Omega Speedmaster, which is certified for the thermal vacuum of a spacewalk. However, Hadfield isn't necessarily a trendsetter when it comes to his wristwatch. The Speedmaster has its own history in orbit: It was the first watch worn on the moon.
In 1962, NASA purchased samples of commercially sold wristwatches to test for space missions, and the agency went with Omega's model. NASA supplied each of the Apollo astronauts with a standard-issue Omega Speedmaster Professional manual-wind wristwatch, along with a Velcro strap.
The watch can be worn for both intra- and extra-vehicular activities. When inside a pressurized cabin such as the ISS, astronauts wear the watch on their wrists just like on Earth. For a moonwalk or other missions outside the cabin, astronauts attach the watch to the outside of their spacesuits using the Velcro strap (see photo above).
Chris Hadfield wears his watch on the wrist while inside the International Space Station. Image courtesy of NASA
Besides its obvious function of keeping time, the Speedmaster also has a stopwatch on the dial's large third hand. There are also three interior dials on the face: a second-hand, ancillary to the conventional time function, a minute-elapsed counter for the chronograph and an hour-elapsed counter. The outside of the dial acts as a Tachymeter, which measures miles per hour (hence the name "Speedmaster").
Astronaut Ed Mitchell's Flown Speedmaster. Image courtesy of NASA/Ulli Lotzmann
All astronauts, including Hadfield, set their watches to Coordinated Universal Time (UTC) -- halfway between Houston and Moscow -- in order to keep in touch with mission control.
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