[FPSPACE] confirmed -- Soyuz entry nearly ended in total disaster

Geert Sassen geert at navtools.nl
Tue Apr 22 22:41:21 EDT 2008


Thanks Jim!

This explains why the cabine looked far more scorched and blackened then 
usual on the first pictures, and it also puts into context the 
description of the 'fire outside', it must have been quite a rough ride.

What worries me is that it now appears to be probably the second time 
around this happened: the previous landing apparently also did not fully 
separate prior reentry, two similar failures in a row makes one worry 
about the condition of Soyuz TMA-12 presently docked to the ISS...

Although soyuz has proven once again to be a very sturdy craft which can 
survive a lot of excess heat & force, it is probably a bit of an 
overstatement to call this a safe mode of descent. The average plane is 
also build to survive a scenario with one or more of its engines 
failing, but that doesn't mean anyone will send a plane into the air if 
there is any doubt regarding its engines...

Finally there still remains the question about telemetry and tracking: 
why wasn't the DM separation failure immediately picked up by mission 
control (according the reports it was noted on Soyuz 5 prior to reentry, 
but in those days they still had tracking vessels) and why didn't they 
notice the guidance was switching to the ballistic mode. According to 
some reports, recovery forces were sent East when the cabine was not 
spotted in time, mentioning that there was an 'overshoot' of the landing 
target, however in fact the capsule landed far west of the target site 
(short of the target) as can be expected with a ballistic reentry, so 
what made them expect an overshoot?

Remember the 'old days', when the Soyuz 33 mission to Salyut 6 
experienced a main engine failure (requiring a de-orbit burn with the 
backup system), that failure alone was enough to place doubt on the 
condition of the engine system of Soyuz 32 (then still docked to Salyut 
6), so they send Soyuz 34 up unmanned with improved engines and landed 
Soyuz 32 unmanned. They might have argued "well, the backup system 
worked okay, so no problem", but they didn't which is the safe thing to 
do in my opinion. Now we are in a situation with not one, but two, craft 
having apparently the same separation problem and it gets interresting 
to see how this will work out for TMA 12....

Regards,

Geert.

jeoberg at comcast.net wrote:
> In a replay of Soyuz-5, the TMA-11 DM failed to separate fully from the Equipment Section, and began entry sideways, severely scorching the front end of the cabin.



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