We've had several questions about when a mission officially "begins". But what about when a mission officially "ends"?

The Apollo Flight Journal stops the mission clock at splashdown. What was the official "end of mission" event for the Shuttle? Did it involve one or more of the following?

  • Touchdown -- the Shuttle equivalent of splashdown
  • The Shuttle has rolled to a stop
  • The last astronaut exits the spacecraft
  • Authority is transferred from Houston to Kennedy
  • The mission clock is stopped
  • Recordings and logs stop
  • 1
    $\begingroup$ I suspect this is tautological: "end of mission" as defined by who, for what purpose? Touchdown time (which is what FAI records care about) is touchdown time. Wheel stop time is wheel stop time. Mission clock stop time is mission clock stop time, etc. $\endgroup$ May 5, 2020 at 4:17
  • 1
    $\begingroup$ @RussellBorogove: Certainly, one could pick any of these events to call the end-of-mission. Just like there are several events proximal to launch which could have been chosen as T=0. But something was officially picked for T=0. Was something similarly designated as the end? $\endgroup$
    – DrSheldon
    May 5, 2020 at 4:31
  • $\begingroup$ From whose perspective @DrSheldon? NASA brass may have one definition whereas mission control may have another. $\endgroup$
    – GdD
    May 5, 2020 at 8:06
  • $\begingroup$ @GdD I'm willing to bet all my SpaceX stock :-) that there is a specific definition for end of a mission and thus when the mission clock is stopped. $\endgroup$ May 5, 2020 at 12:07
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    $\begingroup$ Shuttle missions had an official length so there was obviously an official event that ended them. I just need to find it written down once I get out of bed. $\endgroup$ May 5, 2020 at 12:15

1 Answer 1


Flight Durations are determined from the time of liftoff to MLG Touchdown, specified in days, hours, minutes, and seconds.

MLG = Main Landing Gear

Space Shuttle Missions Summary page 1-2

STS-1 example:

Liftoff 102:12:00:03.9 MLGTD 104:18:20:57 gives 2:06:20:53.1 which you'll see as the flight duration everywhere (usually w/o the .1)

For STS-51-L and STS-107 "flight duration" stopped when contact was lost.

  • 4
    $\begingroup$ It should be noted that there were tons of ways for a crew member to "become famous" after MLG touchdown. The post-wheelstop procedures were quite involved, lengthy, and tedious for the folks on the flight deck...personally, I didn't really heave a sigh of relief until I was back in the Astro Van, hydrating. $\endgroup$
    – Digger
    Jun 5, 2020 at 15:10

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