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#11
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No straight answers from NASA on depressurization event on Soyuz descent
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. "Terrell Miller" wrote in message .. . Jim Oberg wrote: Two weeks ago -- a potentially alarming safety issue. So far, not a single useful word of reply from anyone at NASA. snip These are not unreasonably questions. Any appeal to 'go use FOIA' is not, in my view, reasonable or fair. why? If it's reasonable to ask the questions of a federal agency, why is it unreasonable to amke sure you get an answer? |
#12
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No straight answers from NASA on depressurization event on Soyuz descent
In article . com,
wrote: Not saying the issue should be taken lightly, but wondering if it's medium danger / severe annoyance level, or if it's seriously life threatening on the ground it until it's fixed level? Sort of in between. The suits could have kept them alive had the leak been worse. But if anything further had gone wrong, it could have been a bad day. The margins got uncomfortably thin. Perhaps not "on the ground until it's fixed", but I'd say "urgent flights only until it's at least understood". -- spsystems.net is temporarily off the air; | Henry Spencer mail to henry at zoo.utoronto.ca instead. | |
#13
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No straight answers from NASA on depressurization event on Soyuzdescent
John Doe wrote: One message I saw here had the pressure begin to drop prior to undocking. I would ASSUME that it began to happen when the closed the hatches and vaccumed the vestibule, at which point they may have noticed an imperfect seal. 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. In this case it apparently showed a loss of pressure, but Russian mission control assumed it was a screw-up on their part, and told them to separate from the ISS anyway. The logic of that decision is very suspect, especially given what happened afterwards. This is a soyuz that stayed on station for 6 months. So any leaks would have been noticed during this time. IF the leak happened in the hatch between the orbital module and vacuum, The crew could have closed the hatch between the re-entry module and the orbital module and be safe. (but without toilet and space to move around) This seems to be a leak in the orbital module/reentry module hatch. One has to consider that if the leak was detected prior to undocking, it probably was probably slow enough that they decided to proceed with undocking. It was probably felt that delaying undocking to debug the leak wasn't worth it based on the leak rate. The question one should ask oneself is _why_ the hatch is leaking. If you don't know that, then there is no guarantee that it might get considerably worse when you fire the explosive bolts to separate the orbital module after retrofire. So the big question is whether they lived with the leak and made use of orbital module until it was separated, or if they closed the hatch and stayed in re-entry module all the time. (perhaps repressurising the orbital module once to make use of the toilet). As long as the two modules were joined and the hatch between the two modules was open, the leak wouldn't be noticeable. That's why it manifested itself again after the orbital module was separated, and reentry began. It was probably a very minor glitch that appears to be more serious than it was because of the "secrecy" about it. Russians should be man enough to release the detailed information about this glitch to end any speculation. 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. Pat |
#14
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No straight answers from NASA on depressurization event on Soyuzdescent
John Doe wrote: Derek Lyons wrote: Unfortunatly, the evidence would have been destroyed when the orbital module disintegrated into atmosphere. No, the problem is with the hatch on the top of the descent module, and that they will have. Pat |
#15
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No straight answers from NASA on depressurization event on Soyuz descent
"John Doe" wrote in message ... "Greg D. Moore (Strider)" wrote: As long as NASA astronauts are expected to ride Soyuz, I expect NASA to be forthcoming on the risks. Reverse the table for a minute. Do you really expect the russians be the first to release NASA information on glitches on shuttle flights that carried russians cosmonauts ? Umm, that's not what I'm saying, so no reveral necessary. Do you really think NASA would be happy with this ? NASA is expected to be held accountable and release the informationa about glitches on its shuttle. Yes, and they do. the Russians are expected to be held accountable and release the information about glitches on Soyuz. Which they don't, to NASA or others. But as Jim Oberg and myself are taxpayers, I'd expect NASA to be more demanding of the Russians and then share what they know. As a quasi customer/guest of Soyuz, NASA itself can ask the russians for an explanation, but it isn't its role to make that information public. Customer/guest? Ummm, try partner. And yes, it is its role to make that information public. |
#16
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No straight answers from NASA on depressurization event on Soyuzdescent
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 |
#17
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No straight answers from NASA on depressurization event on Soyuzdescent
Pat Flannery wrote:
The question one should ask oneself is _why_ the hatch is leaking. If you don't know that, then there is no guarantee that it might get considerably worse when you fire the explosive bolts to separate the orbital module after retrofire. also, knowing the 'why' ahead of time gives you an idea if the leak is a linear trendline or not, even if separation doesn't affect things. Kinda nice datapoint to have (see Apollo 13)... -- Terrell Miller "Suddenly, after nearly 30 years of scorn, Prog is cool again". -Entertainment Weekly |
#18
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No straight answers from NASA on depressurization event onSoyuzdescent
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. 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. 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 ? The question one should ask oneself is _why_ the hatch is leaking. Agreed. Luckily, the deffective hatch is back on earth and they may be able to find out what had happened to it. 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 ? |
#19
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No straight answers from NASA on depressurization event on Soyuz descent
Henry Spencer wrote:
In article . com, wrote: Not saying the issue should be taken lightly, but wondering if it's medium danger / severe annoyance level, or if it's seriously life threatening on the ground it until it's fixed level? Sort of in between. The suits could have kept them alive had the leak been worse. But if anything further had gone wrong, it could have been a bad day. The margins got uncomfortably thin. Perhaps not "on the ground until it's fixed", but I'd say "urgent flights only until it's at least understood". I guess when they first noticed a leak during pre-undocking leak-check they considered it to be small enough. They only spent 6 extra minutes or so trying to fix it. This is just about enough time to open the hatch, visually check that the rubber seal looks intact and there is no FODs, then close the hatch and re-check it again. Maybe they simply underestimated it. It it probably difficult to measure dp/dt accurately with all those systems working. I don't know what the standard procedure is when the hatch is leaking but there must be something you can do, some sort of sealant can be applied or they may have spare rubber seals or something like that. They could have spent more time on it but that would've mess up their landing schedule. BTW I think they have at least 2 backups for such leaks: portable O2 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. I guess it was fairly serious but one-off like that kinked tube during EVA. The right solution may be to inspect the seals more often while in orbit, schedule more time on leak checks and don't breathe loudly while doing it. They may also look at pressure sensors. |
#20
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No straight answers from NASA on depressurization event on Soyuzdescent
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 ? |
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