Soyuz MS-22, attached to the ISS, has developed a leak in an external coolant loop in the Instrumentation/Propulsion Module. This spacecraft is needed to return the three cosmonauts who are currently onboard the ISS, either at the end of their mission or as a lifeboat in an emergency.

The Instrumentation/Propulsion Module and Orbital Module are separated from the Descent Module during re-entry. I think I've read somewhere that return from the ISS takes three to four hours. For how long is the Instrumentation/Propulsion module needed during the return flight?


1 Answer 1


The modules separate at landing minus 26 minutes, about three hours after undocking.

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There is a complete timeline here: https://www.nasa.gov/mission_pages/station/structure/elements/soyuz/landing_timeline.html

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    $\begingroup$ +1 From that link, they wait 2 hours 29 minutes until Soyuz is twelve miles from the ISS before the deorbit burn. I wonder if they could reduce that in an emergency? I usually deorbit my Kerbals at a few feet from their space station :) $\endgroup$ Dec 16, 2022 at 17:50
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    $\begingroup$ @DaveGremlin I don't know the constraints but maybe a bigger sep burn (the one at undock + 6 minutes) followed by a sooner deorbit burn might work. But strictly a guess. $\endgroup$ Dec 16, 2022 at 18:54

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