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by m4rtink 2327 days ago
""While this anomaly was corrected in flight, if it had gone uncorrected it would have led to erroneous thruster firing and uncontrolled motion during SM separation for deorbit, with the potential for catastrophic spacecraft failure," Hill said during the meeting."

I guess some things just never get old, citing from https://en.wikipedia.org/wiki/Soyuz_5 :

"The flight was also memorable for its dramatic re-entry. The craft's service module did not separate, so it entered the atmosphere nose-first, leaving cosmonaut Boris Volynov hanging by his restraining straps. As the craft aerobraked, the atmosphere burned through the module. But the craft righted itself before the escape hatch was burned through."

This actually happened three times so far with the Soyuz (in all cases without the loss of crew):

"An incomplete separation between the Service and Reentry Modules led to emergency situations during Soyuz 5, Soyuz TMA-10 and Soyuz TMA-11, which led to an incorrect reentry orientation (crew ingress hatch first)."

(from https://en.wikipedia.org/wiki/Soyuz_(spacecraft)#Service_mod...)

One would kinda expect that past crewed vehicle emergencies would be studied in detail when designing a new one & that the developers would make extra sure they can't reasonably happen with their design.

2 comments

Given commercial pressures would a Boeing reentry vehicle be over designed to such a extent that on such a failure (failure to separate, entering with the wrong attitude ?correct term?) result in "...the craft righted itself before the escape hatch was burned through"?
I would assume it would work the same as with the soyuz, provided that the service module separates/explodes before the capsule reentering the wrong way is irrecoverably damaged.

Basically, all space capsules have their of gravity placed in such a way that they will automatically orient themselves heat shield forward once they encounter the atmosphere. So once the service module is gone, it should flip into the correct orientation just by physics alone.

(BTW, this is the same reason why the Crew Dragon spacecraft keeps it's aft section "ring" attached during a launch escape, where it's super draco thrusters drag it to a safe distance from a failing launcher.

The aft ring prevents the capsule from trying to flip over during the abort. Then once in safe distance from the vapor & debris cloud that used to be the launcher, the aft section is jettisoned and the capsule again automatically re-orients itself heat shield forward.)

I think who you're replying to is implying the escape hatch would have been cheaper if it wouldn't last long enough before burn through during improper re-entry
Yet another crazy story from the USSR space program I was unaware of. Ice in their veins, for sure.