While listening in on today's Crew Dragon 1 rendezvous, I noticed something interesting: the announced duration for the final coelliptic burn was "25 to 35 seconds". And this wasn't just a vague statement by PR: it was the actual transmission from mission control to the capsule.

Back in the Apollo days, NASA was able to give crews burn times to within a second (or less, for some of the brief midcourse corrections). Why isn't SpaceX being this precise?

  • $\begingroup$ Why isn't SpaceX being this precise... in their announced verbal descriptions of the durations of brief midcourse corrections? $\endgroup$
    – uhoh
    Commented Nov 17, 2020 at 1:32
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    $\begingroup$ Well, how long between this communication and the scheduled start of burn? If it is more than a couple orbits, then perhaps they haven't run the final calculation yet. And weren't the Apollo burns controlled by the crew, whereas SpaceX burns are ground-controlled? $\endgroup$ Commented Nov 17, 2020 at 14:00
  • $\begingroup$ @CarlWitthoft: Most Apollo burns were done by computer; the manual maneuvers are few enough to be detailed here. $\endgroup$
    – DrSheldon
    Commented Nov 17, 2020 at 14:53
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    $\begingroup$ Having a deja vu space.stackexchange.com/q/25086/21562 $\endgroup$ Commented Nov 17, 2020 at 15:04
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    $\begingroup$ @EverydayAstronaut not really -- that was a rather different set of circumstances $\endgroup$ Commented Nov 17, 2020 at 15:37


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