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Inspired by this Worldbuilding question about orbital deployment (deploying things to the ground from orbit): What is the quickest that something has actually deorbited and landed from a stable closed orbit around Earth, as in the least amount of time elapsed from orbiting to resting on the ground?

I'm interested in answers involving both controlled landings and uncontrolled impacts (lithobraking), if available.

For example, this article indicates that the SpaceX Crew Dragon used for Crew-7 performed a 15-minute-long deorbit burn and splashed down 37 minutes after the burn finished, so I would count that as 52 minutes from orbit to ground.

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    $\begingroup$ I don't know the answer to your question, but at 3g acceleration it would take 4-5 minutes to decelerate from orbital speed assuming uniform deceleration. I suspect that this is entirely impractical and does not account for air resistance properly, but perhaps is a lower limit. $\endgroup$
    – Slarty
    Commented May 10 at 7:14
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    $\begingroup$ @GremlinWranger The Wikipedia page for Vostok 1 gives 7:25 UTC for the start of the deorbit maneuver and 8:05 for the landing, so about 40 minutes. $\endgroup$
    – mlk
    Commented May 10 at 19:23
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    $\begingroup$ @SF. I think the original Worldbuilding question is already a pretty good place for more hypothetical answers, so I'm thinking it'd be nice for the answers here to focus mostly on actual historical occurrences. $\endgroup$
    – kwc
    Commented May 11 at 20:02
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    $\begingroup$ @CortAmmon: Trying to apply the question to "rods from God"? $\endgroup$
    – Ben Voigt
    Commented May 12 at 1:48
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    $\begingroup$ If the issue is quickest return time from orbit to earth surface as stated in the question, I would suggest that the biggest opportunity of reducing time to earth is reducing the time from the high atmospheric region to earth; not the initial reentry. Free fall is faster than parachute. Powered descent followed by rapid slowdown at earth surface would be even faster. $\endgroup$
    – tckosvic
    Commented May 14 at 17:47

2 Answers 2

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If I can weasel on the "ground" part, it looks like the Corona film buckets took only about 20 minutes from ejection from the satellite to reaching retrieval altitude on their parachutes at 12,000 feet.

Time was moving on toward the space vehicle’s separation. The schedule for this activation was planned to take place at 12:46 p.m.

...

Ahead of us and up 4,000 feet higher we made out an orange tint up against the background of towering cumulus clouds. What a sight to experience. It was 1:05 p.m., just nineteen minutes after the satellite had been reported orbiting over Alaska.

Source: Corona Star Catchers

Good info on the entry sequence here How did the Corona (Key Hole) satellites film canisters deorbit?

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  • $\begingroup$ Wouldn't ejection take place some time earlier than the satellite being overhead? The capsule isn't dropping straight down, but still has quite some velocity in the same direction as the satellite. $\endgroup$
    – asdfex
    Commented May 10 at 16:53
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    $\begingroup$ @asdfex the recovery aircraft was near Hawaii. I see nothing in my post about the satellite being overhead. The "orange tint" refers to the parachute. $\endgroup$ Commented May 10 at 17:45
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While I agree that Corona film buckets could be a winner, I did some orbital mechanics to estimate the time it would take for it to deorbit using some useful data found on a figure from Wikipedia.

enter image description here

If we assume that "retro velocity" means "delta-v of the retro burn" then had this burn been 100% retrograde, it would have slowed the vehicle down so much that it would have reentered the atmosphere (I'll define that as 70km) in 610 seconds (~10 minutes). But if we assume that the "retro angle" was 60°, this would roughly half the amount of delta-v so then it would take 1140 sec (19 minutes) to renter to 70 km.

I suspect that if we had Guinness Book of Records judges looking over our shoulders, they would insist that we add to these figures

  • the duration of the retro burn,
  • the time it takes for the capsule to decelerate in the atmosphere,
  • some time for the capsule to float down to retrieval altitude on its parachute, and
  • then some time for the plane that captures it to return to base and land.

However, these figures do roughly line up with the data from OrganicMarble's Corona Star Catchers reference.

I also think that its quite possible that in at least one case they could have executed a zero-angle retro-burn which would have reentered the capsule in ~10 minutes (plus the length of the burn).

I also looked at satellite collisions. While I suspected that a few fragments from some collisions would have reentered very quickly, it turned out that most of the debris stayed in orbit. I could find no hard evidence of any debris fragment reentering very quickly after the collision. However from this reconstruction video you can see two satellites collide at 16:56:00 and the first yellow fragment appears to stop moving at 17:07.25. So that would technically be an 11 minute and 25 second "partial deorbit" of a satellite.

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