Still Nothing on What is Wrong with Soyuz

Technocrat

Still Nothing on What is Wrong with Soyuz

zogger

Thu Aug 07 18:58:00 -0700 2008

Space+Flight

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The Soyuz rocket capsule is known previously as the premier workhorse of man-in-space, just old tech that was reliable..until lately. The last two missions had pretty bad errors on return, and so far both Russian space agency and NASA engineers are stumped as to what is wrong with it.

"We don't know when we will know. Smart people are working on it," he said, noting that the National Aeronautics and Space Administration and Russia are closely cooperating on the issue. "We are doing the best we can." ed.z.: Just a WAG, but applying a little Holmesism to it, eliminating the impossible so what is left is the answer, even if it seems improbable, maybe they are looking for some engineering problem when there really isn't one to find, and a change of focus might be more fruitful, as in... perhaps it might have been sabotage. I am not saying that is what it is, absolutely no idea or indications of that present, just saying it is at least a theory that could be looked at. And I admit it is because of my nature, I am always initially quite skeptical about high profile and very important apparent coincidences.

Still Nothing on What is Wrong with Soyuz

Michael Smith

Sat Aug 09 16:27:50 -0700 2008
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The problem is that the service module doesn''t always separate from the command module. I think there are 10 or 12 explosive bolts holding the two modules together so if one of those bolts fails to fire then separation doesn't happen and you have a problem.

I small decrease in the reliability of any individual explosive bolt will significantly reduce the expectation that all of the full set of bolts will fire correctly.

One issue is that individually testing small numbers of bolts will not reveal the problem. For me, the solution is to reduce the number of explosive bolts which could cause the mission to fail. Perhaps they should fire six of the bolts before the deorbit burn, then four bolts after the burn. If one of the first six fails to fire then they have time to work on the problem. A failure in one of the four remaining bolts is less likely to happen, so overall reliability should be better.