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No straight answers from NASA on depressurization event on Soyuz descent



 
 
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  #21  
Old October 26th 05, 10:10 AM
Pat Flannery
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Default No straight answers from NASA on depressurization event on Soyuzdescent



John Doe wrote:

Pat Flannery wrote:


The leak was noticed prior to undocking; apparently there is a test
where they enter the reentry module and seal the hatch to the orbital
module, then lower the pressure in the orbital module to make sure the
hatch joining the two maintains pressure integrity before they separate
from the station.



OK that changes things a bit. On the other hand, if the leak rate was
steady, they would still have been able to decide if the loss of
pressure between time of orbital module separation and time of reaching
10,000 feet altitude would have be low enough that it wasn't a concern.

I can also see this as having taken some of their time after unbdocking
to perhaps test, examine the hatch of the descent module.


The leak would only show up once the orbital module was detached, and
that occurs after retrofire and shortly before actual reentry begins, so
it wouldn't be a good idea to start climbing around in the reentry
capsule at that point.
One of the things that may have led to mission control telling them to
undock despite the possible leak could be the timeline constraint to
land the capsule in the intended recovery area...delay things too long
and you end up at the wrong orbital geometry to land at the planned
site, and have to come up with a new timeline for reentry and landing.

Do they have any data on g forces/impact force at the time that soyuz
docked ? When they moved the soyuz from one port to another, would they
have performed the same tests ? (which, if they were successful, would
indicate that the leak problem would have been caused after/during that manoeuver.


That I'm not sure of The dockings could be done with the hatch between
the orbital and reentry module in the open position.
You probably don't want to open and close the hatch more times than is
necessary for fear of damaging its seals.




told them to separate from the ISS anyway.
The logic of that decision is very suspect, especially given what
happened afterwards.



What did happen afterwards ?


That's when the leak reappeared during descent, it occurred once they
had jettisoned the orbital module.
What makes this spooky is how this is very close to what happened to
Soyuz 11, and led to the death of its crew:
http://www.astronautix.com/flights/soyuz11.htm

"After the crew has left the station, taken their seats in the capsule,
and closed the hatch between the Soyuz BO orbital module and SA re-entry
capsule, the strained voice of Volkov comes from space: 'Hatch not
hermetically sealed? What's happening? What's going on?'. All this
response to the fact that the caution and warning panel 'Hatch open'
light has not gone out. Yeliseyev calmly advises the crew, 'Don't panic.
Open the hatch, and move the wheel to the left to open. Close the hatch,
and then move the wheel to the right six turns with full force'. The
crew does this several times, but the light still won't go out. On a
final attempt, with 6.5 turns of the wheel, the light goes out. On the
second half of he 15th orbit, the crew lowers the pressure in the BO to
160 mm, and the hatch proves to be air-tight.

On the 16th orbit the crew separates their Soyuz from the Salyut
station. At 21:35 they report normal separation and that they 'can see
how the station moves away from the spacecraft'. They have enough
propellant to stop the separation velocity, and take photographs of the
station from 10 to 15 m away. They then back away to 30-40 m, and
Patsayev takes another set of photographs documenting the condition of
the station.

* 1971 Jun 29 - Landing of Soyuz 11 Return Crew: Dobrovolsky
http://www.astronautix.com/astros/dobolsky.htm, Patsayev
http://www.astronautix.com/astros/patsayev.htm, Volkov
http://www.astronautix.com/astros/volkov.htm, Nation: USSR.

The re-entry capsule was recovered June 29, 1971 23:17 GMT, but
when the hatch was opened it was found that the crew had perished
due to a loss of cabin atmosphere. A pressure equalization valve
was jerked loose at the jettison of the Soyuz Orbital Module. The
valve was not supposed to open until an altitude of 4 km was
reached. The three-man crew did not have space suits. The Soyuz
was thereafter redesigned to accommodate only two crew, but in
spacesuits. The actual Soyuz 11 Prime Crew was Leonov, Kubasov,
and Kolodin. Dobrovolskiy, Volkov, Patsayev were their backups
(and support crew to Soyuz 10). Kubasov was grounded by physicians
few days before launch, and the back-up crew ended up going instead."



They're probably concerned that their decision to allow to allow the
Soyuz to separate from the ISS despite the leak indication would look
flawed...as indeed it was.



What have the astronauts actually revealed that is factual ? Any leak
rates ? Was the leak generating a loud hiss ? Was it noticeable or was
it just a very tiny leak that was noticed only be the precise
instruments ?



Ground control apparently noticed it on their instruments:
http://www.msnbc.msn.com/id/9697668/

Pat
  #22  
Old October 27th 05, 04:38 PM
Jim Oberg
external usenet poster
 
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Default No straight answers from NASA on depressurization event on Soyuz descent

I have the precise psi values but did not
use them because the number was on a very
tightly-guarded memo and would point to
a very small group of suspects. So I converted
to percentages, retaining accuracy while
protecting source.




"John Doe" wrote in message ...
dmitrik wrote:
repress bottle and suit air. They did repress the cabin with O2 but I
don't know whether they had to switch completely to suit air.


Does anyone know what pressure the cabin went down to before they
released some O2 ?

I assume it starts off at 14.7 when they leave the station, right ?

Also, between the time they undock from orbital module and the time the
hatch is opened on the ground, wouldn't O2 have to be released from time
to time even in normal circumstances to keep the 3 occupants awake in
this tight space ?

If the cabin is at 14.7 and the occupants close the visor of the sokhol
suits, would they then be getting 100% O2 at 14.7 ? or just mixture of
N2 and O2 ? If cabin were truly leaking, I take it that the suits would
drop down to about 5psi, at which point it would be pure O2 into the
suits ?


have they released any information on whether the leak was audible or
not ? If it was not audible, could it have been a faulty valve instead
of actual hatch leaks ?

Is it possible that this event was so trivial that the cosmonauts didn't
bother doing anything out of the ordinary and thus this would explain
why there is so little information about it ?



  #23  
Old October 27th 05, 04:39 PM
Jim Oberg
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Default No straight answers from NASA on depressurization event on Soyuz descent

No, it's NASA's bad, and continues to be.


"Terrell Miller" wrote in message
news
Jim Oberg wrote:
Here's why. It is a 'news story' request that requires a degree of
timeliness,
while the FOIA channel is a guaranty of MONTHS of delay. It is USED to
insure that kind of delay, to squelch public interest in the story.


sorry Jim, I misread your original post: I thought you were saying it was
unfair for a *non-NASA* entity to submit a FOIA, but what you said was
that it's unfair for NASA to ask you to request the data that way instead
of giving you a straight answer, to which I totally agree.

My bad.


--
Terrell Miller


"Suddenly, after nearly 30 years of scorn, Prog is cool again".
-Entertainment Weekly


  #24  
Old October 27th 05, 05:34 PM
Herb Schaltegger
external usenet poster
 
Posts: n/a
Default No straight answers from NASA on depressurization event on Soyuz descent

On Thu, 27 Oct 2005 10:38:27 -0500, Jim Oberg wrote
(in article ):

"John Doe" wrote in message ...
dmitrik wrote:
repress bottle and suit air. They did repress the cabin with O2 but I
don't know whether they had to switch completely to suit air.


Does anyone know what pressure the cabin went down to before they
released some O2 ?

I assume it starts off at 14.7 when they leave the station, right ?

Also, between the time they undock from orbital module and the time the
hatch is opened on the ground, wouldn't O2 have to be released from time
to time even in normal circumstances to keep the 3 occupants awake in
this tight space ?

If the cabin is at 14.7 and the occupants close the visor of the sokhol
suits, would they then be getting 100% O2 at 14.7 ? or just mixture of
N2 and O2 ? If cabin were truly leaking, I take it that the suits would
drop down to about 5psi, at which point it would be pure O2 into the
suits ?


have they released any information on whether the leak was audible or
not ? If it was not audible, could it have been a faulty valve instead
of actual hatch leaks ?

Is it possible that this event was so trivial that the cosmonauts didn't
bother doing anything out of the ordinary and thus this would explain
why there is so little information about it ?


I have the precise psi values but did not
use them because the number was on a very
tightly-guarded memo and would point to
a very small group of suspects. So I converted
to percentages, retaining accuracy while
protecting source.


Um . . . by saying that just now, didn't you just essentially point out
your source if anyone happens to read s.s.h or s.s.s ?


--
"Fame may be fleeting but obscurity is forever." ~Anonymous
"I believe as little as possible and know as much as I can."
~Todd Stuart Phillips
www.angryherb.net

  #25  
Old October 27th 05, 08:14 PM
Pat Flannery
external usenet poster
 
Posts: n/a
Default No straight answers from NASA on depressurization event on Soyuzdescent



Jim Oberg wrote:

I have the precise psi values but did not
use them because the number was on a very
tightly-guarded memo and would point to
a very small group of suspects. So I converted
to percentages, retaining accuracy while
protecting source.



Do you have any detailed info on what the pressure drop during the
descent module hatch seal test before the undocking from the ISS was?

Pat
 




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