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When listening to Space Shuttle countdown I notice the endings "and counting" and "and holding". I can imagine what "and counting" means, but what is "and holding"? Countdown has stopped? Why?

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    It's old Mercury program countdown jargon. "And counting" means that the countdown clock is ticking (downward). "And holding" means that the countdown clock has been stopped. It was common for there to be multiple "holds" in the countdown for a Mercury space launch, as items were checked in the checklist and problems were found. (Of course, the idioms have been adopted by other domains.) – Hot Licks Jul 9 '15 at 23:46
  • If they find any system that is not "go" (i.e., ready for launch), the launch becomes a "no-go". When the launch is canceled, it is said to have been "scrubbed". – Brian Hitchcock Jul 10 '15 at 9:04
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Shuttle launches clock a countdown from T-43 hours (i.e., 43 hours before liftoff) to T-0 (liftoff). The clock is important, not just to watch the time go by, but because dozens of activities are keyed to it. For example, at T-2 minutes, the crew knows to close and lock their visors, and at T-6.6 seconds, they ignite the engine. For details go here.

If things are going smoothly, the clock runs and is said to be counting. If there's a problem, flight control stops the clock, and it is said to be "holding," from its meaning of grasping and not letting go.

  • Or, really? They stop and start countdown so easily for multiple times? I thought that if some issue arises, entire launch must be cancelled. – Paul Jul 10 '15 at 0:39
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    No, if some issue arises and they can fix it in time, they resume the countdown. – deadrat Jul 10 '15 at 0:43
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"The ship is up to 5000 meters and holding, sir"

The ship has reached 5000 meters and is sustaining this altitude.

  • But that is a different sense of the word, not related to the space launch jargon. – Hot Licks Jul 10 '15 at 1:59
  • Not really—it's holding steady, at the same value. Clock or altitude, they're still "holding". – Brian Hitchcock Jul 10 '15 at 8:59

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