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Per the timeline mentioned in the webcast the Crew Dragon separated from its trunk before the deorbit burn.

I suppose that happens so clean separation can be confirmed before committing to deorbit as reentry with the trunk still attached would be a problem (and it saves some fuel too).

But it means now there is a standalone Dragon trunk in LEO which might take some time to slow down to (uncontrollably) reentry.

What orbit was it left in? Did the Dragon lower the perigee meaningfully before the separation or is it left near the current ISS altitude?

And how long is it expected to stay there before being slowed down enough to burn in the atmosphere?

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According to a tweet from Jonathan McDowell, it is in a nearly circular orbit.

Dragon Trunk cataloged as object 44064 in a 395 x 401 km orbit, only a bit below ISS which is in a 406 x 411 k m orbit. Looks like the Dep-3 and Dep-4 burns were quite small.

Short of information released from SpaceX, lifetime appears to be speculation for now. Mostly depends on the mass/density of the trunk. As it's empty, it could deorbit pretty rapidly (few months). But that remains to be seen.

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Referring to this orbital decay calculator using BowlOfRed’s initial altitude figure and assuming the trunk masses about 830kg with a 14 m^2 cross section, it should reenter in around one year.

This is highly sensitive to the influence of solar weather on Earth’s atmosphere, so it could be much sooner or much later.

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    $\begingroup$ space.stackexchange.com/a/9063/5979 says "less than 1000kg". $\endgroup$
    – BowlOfRed
    Commented Mar 9, 2019 at 0:47
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    $\begingroup$ Citation needed, but I'll assume 830kg in my estimate instead of 2 tons, since that gives a nice round year time to reentry. $\endgroup$
    – Russell Borogove
    Commented Mar 9, 2019 at 1:14
  • $\begingroup$ Yes, nice round answers are always the truest answers ;-) $\endgroup$
    – user36480
    Commented Jun 11, 2020 at 8:26
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    $\begingroup$ We now have some data to confirm this; for example, the trunk of Crew-4 is expected to re-enter in a few days, and it was separated from the crew module about half a year ago. So it was in space for a year, but only half a year not docked to the ISS. $\endgroup$
    – OrOrg
    Commented Apr 3, 2023 at 10:26

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