On the ISS, the timezone used is UTC. Thus it is reasonnable to assume that all nations implied in the ISS program use UTC for all their space programs to ease ground crew's work while they may work on several space programs. But what about the other nations with space program?

EDIT: When asking for other nation with space program, I was expecting answer including nation from the linked wikipedia list not involved in the ISS space program (e.g. India, North Corea, ...)

  • $\begingroup$ I seem to recall reading somewhere that where the rest of the world uses UTC, Russia uses (or once used) Moscow time for their independent activities, but I can't find a reference to back that up. $\endgroup$
    – Anthony X
    Commented Sep 27, 2015 at 1:24
  • $\begingroup$ North Korea claims to be planning another launch soon… UTC loses its advantages for a country that fits in one time zone, doesn't cooperate with anyone, and isn't sending the probe very far (if ever communicating with it at all). $\endgroup$ Commented Sep 27, 2015 at 15:24

1 Answer 1


There are two different issues here- what time zone do the people in space use and what time zone the mission control center uses. The crew uses the elapsed time.

To quote Paul Lockhart's answer to a similar question,

....On the shuttle we use mission elapsed time. This is kept by the computers as soon as launch is initiated. And once we are on orbit, we have our own watches that we then set to the computer’s time so that we each are keeping track of our duties according to the mission elapsed time. When we docked to the station, they used Greenwich Mean Time, GMT, .... on the shuttle we use mission elapsed time, and on the station, they use Greenwich Mean Time.

Apparently, almost all of the space industry uses UTC. As ESA explains in a blog,

....the space industry (and many other organisations facing similar issues) use a standard time zone called UTC – Coordinated Universal Time.

Mir used Moscow Standard Time though.

  • $\begingroup$ What about those pesky leap seconds? $\endgroup$ Commented Sep 27, 2015 at 19:36
  • $\begingroup$ @DeerHunter Yes, them too. "The number of seconds in a minute is usually 60, but with an occasional leap second, it may be 61 or 59 instead.[13] Thus, in the UTC time scale, the second and all smaller time units (millisecond, microsecond, etc.) are of constant duration, but the minute and all larger time units (hour, day, week, etc.) are of variable duration." Leap seconds are pretty obviously not a problem for Mission Elapsed Time, since MET is just a count of elapsed time, not an absolute point in time. $\endgroup$
    – user
    Commented Sep 27, 2015 at 21:08
  • $\begingroup$ Most spacecraft actually use GPS time, which never includes leap seconds. They might have a constant that's updated when leap seconds happen to keep the difference in time, if the UTC time is needed for some reason. $\endgroup$
    – PearsonArtPhoto
    Commented Sep 27, 2015 at 23:40

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