"Explosive" spacewalk: preventing the Soyuz separation/reentry problem

[MeteorWayne]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Easy there turbo, I asked it just as a question. &nbsp; When reading about Soyuz 11, their failure came when they undocked from one of the small soviet space stations and it was linked to the explosive bolts was it not?Edit: maybe it was Soyuz 5, I thought I heard it about Soyuz 11, and the Soviets were trying to cover it up for PR reasons.&nbsp; &nbsp; &nbsp; I understand the articles here are about the explosive bolts which break the connections between the spacecraft's crew capsule and its propulsion module during descent.&nbsp;&nbsp; Thanks for answearing my question about the docking though.&nbsp;&nbsp; My only education about Space and Rocketry come from the internet, so sometimes I get bad info; I do try to compare what I find to other articles. &nbsp;&nbsp; &nbsp; <br />Posted by neuvik</DIV><br /><br />Sorry, large influx of people who don't care about facts here at SDC, and I was a bit cranky.</p><p>All ISS docking is via a capture, then reel in and latch mechanism. Explosive bolts would most likel make a docking port unreliable for future dockings, so would not be applicable for any on the ISS that get reused regularly.</p><p>WayneMan</p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[CalliArcale]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Easy there turbo, I asked it just as a question. &nbsp; When reading about Soyuz 11, their failure came when they undocked from one of the small soviet space stations and it was linked to the explosive bolts was it not?Edit: maybe it was Soyuz 5, I thought I heard it about Soyuz 11, and the Soviets were trying to cover it up for PR reasons.&nbsp; &nbsp; &nbsp; I understand the articles here are about the explosive bolts which break the connections between the spacecraft's crew capsule and its propulsion module during descent.&nbsp;&nbsp; Thanks for answearing my question about the docking though.&nbsp;&nbsp; My only education about Space and Rocketry come from the internet, so sometimes I get bad info; I do try to compare what I find to other articles. &nbsp;&nbsp; &nbsp; <br /> Posted by neuvik</DIV></p><p>You might want to visit astronautix.com (not entirely accurate all the time, but definitely the most comprehensive source that's freely available) and russianspaceweb.com (which is an awesome source for Russian stuff). </p><p>Soyuz 11 was the first&nbsp; spacecraft to successfully visit a space station.&nbsp; The crew docked with Salyut 1, occupied it for about a month, and then piled into their Soyuz to return home.&nbsp; What happened next is not entirely clear, in part because the Soviets did indeed try to cover up the details.&nbsp; They couldn't cover it all up, though, because the cosmonauts were killed.&nbsp; It appears that it happened when they jettisoned the orbital module following retrofire.&nbsp; It has been suggested that vibrations either jostled or confused a pressure equalization valve, intended to open when the parachutes were deployed to allow the cabin to equalize to the outside pressure.</p><p>Since they were in space at the time, the outside pressure was effectively zero, and the cabin atmosphere was vented to space in about 112 seconds, if the account at astronautix.com is correct.&nbsp; (Details sometimes change in reports about Russian spacecraft, because of all the secrecy during the Soviet years.)&nbsp; The crew took less than a minute to die.&nbsp; (After landing, technicians were able to recover the biometric telemetry data showing crew heartrate and respiration.)&nbsp; Since they were out of communications normally from retrofire to parachute deploy, nobody on the ground had any idea anything was wrong until they were descending under parachute, silent but right on target.&nbsp; Recovery crews landed next to the vehicle only two minutes after touchdown, but it was already much too late.&nbsp; On autopsy, all were found to have hemmoraghes in their brains, blood in their lungs, and nitrogen in their blood -- they had died by decompression.</p><p>astronautix.com has this from Kaminin's diary:</p><p><em>The idea of plugging the vent with a finger is absurd. Had they done so, they would have had only 15 to 17 minutes to work the problem before the onset of G-forces. Imagine the real situation - retrofire was normal - the BO module jettisoned - suddenly the depress light on the caution warning panel is on! Dobrovolsky checks the hatch, but it's not the hatch -- and there are only 25 to 30 seconds until they all become unconscious. Volkov and Patsayev undo their straps and turn on the radio. The whistling of the air can only be heard at the commander's seat - where the vent valve is located. Kamanin discontinues diary entries for two years after this date.<br /></em> </p><p>No other crews ever successfully visited Salyut 1, and it was deorbited deliberately a few months later.&nbsp; This had nothing to do with the loss of Soyuz 11; it was only intended to last only three months anyway.&nbsp; It actually orbited for 6, though, since it was kept up longer to observe the effects of the atmosphere upon it. </p> <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[MeteorWayne]

<br />&nbsp;During the spacewalks, the station&rsquo;s hatches will be sealed and Chamitoff will remain in the Soyuz as a contingency in the unlikely event that the spacewalkers are unable to repressurize the Pirs docking compartment and must use the Soyuz to move to another docking port to re-enter the station. <br /><br />Volkov and Kononenko are set to exit the station Thursday (July 10) at about 2:20 p.m. EDT. During the 6-hour excursion, they will inspect the Soyuz, checking the attachment of the return module to the propulsion module. They also will retrieve a suspect pyrotechnic bolt for inspection by engineers on the ground. <br /><br />If time permits, the spacewalkers will install a docking target on the Zvezda service module. Otherwise, they will complete that task on a second spacewalk on July 15. On that spacewalk they also will retrieve an experiment from the station&rsquo;s exterior and install another. <br /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[sprockit]

I, for one, am confused with the contingency plans if the EVA cannot be closed out with the Pirs airlock.&nbsp; For the Soyuz to be used as an airlock, it would have to be undocked from the station and access to the orbital module (the back up airlock) would need to be made through the front hatch.&nbsp; This would mean that the docking probe would have to be removed and so on.&nbsp; I am not aware of this contingency plan being made before.&nbsp; Also, Quest was designed to accomodate the Orlan EMUs.&nbsp; Obviously, I am missing something here.

 

[CalliArcale]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I, for one, am confused with the contingency plans if the EVA cannot be closed out with the Pirs airlock.&nbsp; For the Soyuz to be used as an airlock, it would have to be undocked from the station and access to the orbital module (the back up airlock) would need to be made through the front hatch.&nbsp; This would mean that the docking probe would have to be removed and so on.&nbsp; I am not aware of this contingency plan being made before.&nbsp; Also, Quest was designed to accomodate the Orlan EMUs.&nbsp; Obviously, I am missing something here. <br /> Posted by sprockit</DIV></p><p>The problem is that while Pirs is depressurized, the American astronaut, Greg Chernitoff, cannot get to the Soyuz, because it's on the other side of Pirs.&nbsp; Really, there's almost no risk of being unable to repress Pirs, but mission controllers don't like the idea of anybody being cut off from the escape vehicle for any length of time. </p><p>If the spacewalkers can't repressurize Pirs, they'll enter the Soyuz orbital module via the hatch between Pirs and the Soyuz.&nbsp; I don't think there's any worry that they won't be able to get back into Pirs at all.</p> <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[sprockit]

Many thanks for the clarification.&nbsp; Makes sense now!

 

[Zipi]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Many thanks for the clarification.&nbsp; Makes sense now! <br />Posted by sprockit</DIV><br /><br />I didn't get it... Because if Quest Airlock can support Orlan space suits as well, why they want to do this at hard way with Pirs? Quest Airlock has been used much often and it has been proven reliable. <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I didn't get it... Because if Quest Airlock can support Orlan space suits as well, why they want to do this at hard way with Pirs? Quest Airlock has been used much often and it has been proven reliable. <br />Posted by Zipi</DIV><br /><br />Perhaps it's closer to the area of today's spacewalk? <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[Zipi]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Perhaps it's closer to the area of today's spacewalk? <br />Posted by MeteorWayne</DIV></p><p>That is probably true, but still I have to ask is the shorter distance really a good enough reason to use Pirs and have this "risk" and uncorfortability to Chamitoff? I can imagine only two reasons beside this distance issue to use Pirs:</p><p>1. Russians want to use their hardware. They want to show that they can do it by their ways.<br />2. Mission control wants to test Pirs as airlock usage. They probably want to make sure they have redundant airlock functions available at all time.</p><p>But what is the correct reason or are all of those correct?</p> <div class="Discussion_UserSignature"> </div>

 

[CalliArcale]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>That is probably true, but still I have to ask is the shorter distance really a good enough reason to use Pirs and have this "risk" and uncorfortability to Chamitoff? I can imagine only two reasons beside this distance issue to use Pirs:1. Russians want to use their hardware. They want to show that they can do it by their ways.2. Mission control wants to test Pirs as airlock usage. They probably want to make sure they have redundant airlock functions available at all time.But what is the correct reason or are all of those correct? <br /> Posted by Zipi</DIV></p><p>Translating (moving across the exterior of the spacecraft) is hard, exhausting work.&nbsp; They may be weightless, but they are not massless, and the suits are pressurized to 5 PSI.&nbsp; Closing one's hand is like squeezing a tennis ball, and translating requires opening and closing one's hands repeatedly.&nbsp;&nbsp; So shortening the distance really does make a big difference. </p><p>EDIT: Testing the hardware is unneccesary; the Russians have done many spacewalks from Pirs already.&nbsp; And it won't be done with purely Russian hardware; they're using NASA's helmet cams so that engineers will be able to get almost as good as look into the Plane 5 niche as Kononenko will get. </p> <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[DrRocket]

<p>The problem that I am still having is why they need to recover a bolt from the vehicle at all.</p><p>Are there no&nbsp;representative explosive bolts in existence other than the ones already installed ?&nbsp; Aren't there any more on the ground somewhere ?</p><p>Given that&nbsp; a couple of explosive bolts seem to have failed, why do they expect that one bolt taken from the vehicle will be representative of the propulation of bad bolts ?&nbsp; I would have expected a large population of bolts from the same manufacturing process, the same lot if possible, to be put through testing to isolate the failure mode.&nbsp; That process would require a lot more than one bolt, unless the failure rate was approaching 100%.</p><p>Have they selected the specific bolt to be recovered for some particular reason ?&nbsp; What is unique about it ?</p><p>If the only bolts that could&nbsp; possibly provide a clue as to the problems already encountered are on the orbiting vehicle, then what are the possible corrective actions ?&nbsp; Are all bolts on the&nbsp; ground known&nbsp; to be free of whatever the defect might be ?&nbsp;&nbsp; </p><p>I think there is more to the story than they are telling us.&nbsp;&nbsp;This is a truly unusual approach to a failure investigation.</p> <div class="Discussion_UserSignature"> </div>

 

[Zipi]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The problem that I am still having is why they need to recover a bolt from the vehicle at all.Are there no&nbsp;representative explosive bolts in existence other than the ones already installed ?&nbsp; Aren't there any more on the ground somewhere ?Given that&nbsp; a couple of explosive bolts seem to have failed, why do they expect that one bolt taken from the vehicle will be representative of the propulation of bad bolts ?&nbsp; I would have expected a large population of bolts from the same manufacturing process, the same lot if possible, to be put through testing to isolate the failure mode.&nbsp; That process would require a lot more than one bolt, unless the failure rate was approaching 100%.Have they selected the specific bolt to be recovered for some particular reason ?&nbsp; What is unique about it ?If the only bolts that could&nbsp; possibly provide a clue as to the problems already encountered are on the orbiting vehicle, then what are the possible corrective actions ?&nbsp; Are all bolts on the&nbsp; ground known&nbsp; to be free of whatever the defect might be ?&nbsp;&nbsp; I think there is more to the story than they are telling us.&nbsp;&nbsp;This is a truly unusual approach to a failure investigation. <br />Posted by DrRocket</DIV><br /><br />The bolts at ground have not had the same "treatment" as the bolts currently at Soyuz, because of the lauch vibrations, space radiation, etc... And I also think they have some clues that it is that specific bolt that have failed which they are now removing. You probably can see some bendings etc. to be able to determine which bolt have failed. <div class="Discussion_UserSignature"> </div>

 

[CalliArcale]

I think one of their specific concerns is whether or not long exposure to the electromagnetic environment around the ISS may have something to do with it.&nbsp; That would be very difficult to reproduce on the ground. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[CalliArcale]

<p>Kononenko is being moved into position now.&nbsp; Volkov is operating the Strela crane.&nbsp; It's a delicate process, of course, since they don't want to bump anything accidentally.</p><p>Question for our Russian friends -- do you know if the Strela is motorized or if it is entirely manual?&nbsp; I believe the early Strelas were manually operated (muscle power). </p> <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[Zipi]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Kononenko is being moved into position now.&nbsp; Volkov is operating the Strela crane.&nbsp; It's a delicate process, of course, since they don't want to bump anything accidentally.Question for our Russian friends -- do you know if the Strela is motorized or if it is entirely manual?&nbsp; I believe the early Strelas were manually operated (muscle power). <br />Posted by CalliArcale</DIV><br /><br />I'm not from Russia nor know this for sure, but I'm pretty certain that Strela is entirely hand operated. It surely looks like it is... And here are a copy&paste from SDC live reports: (see the bolded section)</p><p class="MsoNormal"><strong><span style="font-size:10pt;font-family:'Arial','sans-serif'">Spacewalk Underway Again <br />10 July 2008 4:38 p.m. EDT</span></strong><span style="font-size:10pt;font-family:'Arial','sans-serif'"> </span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:'Arial','sans-serif'">Spacewalker Kononenko is now on his way to the work site on the Soyuz spacecraft</span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:'Arial','sans-serif'">Kononenko encountered earlier difficulties getting into a foot restraint, which is designed to allow him to ride the 50-foot boom of the Strela crane to the work site.</span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:'Arial','sans-serif'">Russian mission control finally instructed the cosmonaut to improvise and tether himself to the crane. <strong>Fellow spacewalker Volkov operated the hand-powered crane to move Kononenko.</strong></span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:'Arial','sans-serif'">The third member of the space station crew, U.S. astronaut and flight engineer Greg Chamitoff, is sitting inside the Soyuz spacecraft for the duration of the six-hour spacewalk in case of an emergency.</span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:'Arial','sans-serif'">&ldquo;We can probably go ahead and scare Greg a little through the window,&rdquo; one cosmonaut joked.</span></p><p class="MsoNormal"><em><span style="font-size:10pt;font-family:'Arial','sans-serif'">NASA is broadcasting the spacewalk live on NASA TV. You are invited to follow the mission using SPACE.com&rsquo;s NASA TV feed, which is available by <u><span style="color:blue"><a href=""><span style="text-decoration:none">clicking here</span></a></span></u> or using the button at the left.</span></em><span style="font-size:10pt;font-family:'Arial','sans-serif'"> </span></p><p style="text-align:right" class="MsoNormal" align="right"><span style="font-size:10pt;font-family:'Arial','sans-serif'">-- Jeremy Hsu</span></p> <div class="Discussion_UserSignature"> </div>

 

[CalliArcale]

<p>*chuckles*&nbsp; Cosmonauts and astronauts tend to have good senses of humor.&nbsp; &nbsp; Thanks for confirming that the Strela is hand-operated.&nbsp; Still hope some of our Russian members will wander in, but I think it's the middle of the night over there.</p><p>This has been a fun spacewalk to follow on NASA TV.&nbsp; Kononenko just finished with the camera.&nbsp; He was having a lot of trouble with it for a while -- the glare of the sun made it impossible to see the viewfinder, and impossible for him to tell what Volkov could see -- that the camera was still switched off.&nbsp; &nbsp; That makes me feel much better about my own photographic endeavors!</p> <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[CalliArcale]

<p>And he's cutting!</p><p>Kononenko joked that about breaking the spacecraft and then started working on the cloth insulation.&nbsp; It appears to be rather tough, which makes sense as it is designed to provide micrometeoroid protection.&nbsp; He has already installed blaze orange insulated covers over the thrusters that are now exposed.</p> <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[Zipi]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>*chuckles*&nbsp; Cosmonauts and astronauts tend to have good senses of humor.&nbsp; &nbsp; Thanks for confirming that the Strela is hand-operated.&nbsp; Still hope some of our Russian members will wander in, but I think it's the middle of the night over there.This has been a fun spacewalk to follow on NASA TV.&nbsp; Kononenko just finished with the camera.&nbsp; He was having a lot of trouble with it for a while -- the glare of the sun made it impossible to see the viewfinder, and impossible for him to tell what Volkov could see -- that the camera was still switched off.&nbsp; &nbsp; That makes me feel much better about my own photographic endeavors! <br />Posted by CalliArcale</DIV><br /><br />Yep, it is a middle of the night here at the Russian border (Finnish time 00:04): http://maps.google.com/maps?f=q&hl=en&geocode=&q=imatra&sll=37.0625,-95.677068&sspn=52.550571,111.796875&ie=UTF8&ll=61.172145,28.753077&spn=16.287241,55.898438&z=5</p><p>I'd like as well to hear some comments of Russian members of this forum... But I'm afraid that they probably don't have too much more information about these things than we have.</p> <div class="Discussion_UserSignature"> </div>

 

[CalliArcale]

And he's in.&nbsp; Kononenko has put away his knife and is going to start working on disconnecting the pyrobolt now.&nbsp; To my inexperienced eye, everything looks very clean. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[Zipi]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>And he's in.&nbsp; Kononenko has put away his knife and is going to start working on disconnecting the pyrobolt now.&nbsp; To my inexperienced eye, everything looks very clean. <br />Posted by CalliArcale</DIV><br /><br />Looks pretty clean (or fluffy because of that blanket), but still I would doubt a little bit to entering to the atmosphere with that hacked Soyuz ship. <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-laughing.gif" border="0" alt="Laughing" title="Laughing" /></p> <div class="Discussion_UserSignature"> </div>

 

[CalliArcale]

<p><img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-tongue-out.gif" border="0" alt="Tongue out" title="Tongue out" /></p><p>They're installing a makeshift handrail that will cover a fluid line between the two thrusters in the work area.&nbsp; This will protect it from accidental damage while they disconnect wires. </p> <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[Zipi]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>They're installing a makeshift handrail that will cover a fluid line between the two thrusters in the work area.&nbsp; This will protect it from accidental damage while they disconnect wires. <br />Posted by CalliArcale</DIV><br /><br />This start to sound and look like like some Lada repair operation at Siberia at the good old times... Some technical difficulties and drawbacks, but not&nbsp;something which couldn't be fixed with a bigger hammer and a couple of pairs of tights. <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-laughing.gif" border="0" alt="Laughing" title="Laughing" /></p><p>Don't get me wrong because I really esteem the Russian space efforts and even their very robust Ladas (even I'm a Ford fanatic). <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-tongue-out.gif" border="0" alt="Tongue out" title="Tongue out" /></p> <div class="Discussion_UserSignature"> </div>

 

[shuttle_guy]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>You might want to visit astronautix.com (not entirely accurate all the time, but definitely the most comprehensive source that's freely available) and russianspaceweb.com (which is an awesome source for Russian stuff). Soyuz 11 was the first&nbsp; spacecraft to successfully visit a space station.&nbsp; The crew docked with Salyut 1, occupied it for about a month, and then piled into their Soyuz to return home.&nbsp; What happened next is not entirely clear, in part because the Soviets did indeed try to cover up the details.&nbsp; They couldn't cover it all up, though, because the cosmonauts were killed.&nbsp; It appears that it happened when they jettisoned the orbital module following retrofire.&nbsp; It has been suggested that vibrations either jostled or confused a pressure equalization valve, intended to open when the parachutes were deployed to allow the cabin to equalize to the outside pressure.Since they were in space at the time, the outside pressure was effectively zero, and the cabin atmosphere was vented to space in about 112 seconds, if the account at astronautix.com is correctby CalliArcale</DIV></p><p>I suggest readind the book Two sides of the Moon by Dave Scott and Alexie Leonov. Leonov was a hight up mgr. in the cosmonaut program at the time. He relates how he was concerned about having the equalization valve in the auto position. He was concerned that it would open too early. He said he told the crew not to trust it and to select the manual position. In that position a crewman would have to leave his seat after the main parachutes opened and open the valve. The crew ignored his advice. When the orbital module pyro bolts fired they all fired at once not in sequence. The pyro shock caused the equalization valve to open.</p><p>&nbsp;</p><p>&nbsp;</p><p>La&nbsp;</p><p><br /><br />&nbsp;</p> <div class="Discussion_UserSignature"> </div>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The bolts at ground have not had the same "treatment" as the bolts currently at Soyuz, because of the lauch vibrations, space radiation, etc... And I also think they have some clues that it is that specific bolt that have failed which they are now removing. You probably can see some bendings etc. to be able to determine which bolt have failed. <br />Posted by Zipi</DIV></p><p>If that is the concern, then there really is something amiss.&nbsp; It is quite normal for components to be tested in shock and vibration fixtures far in excess of flight environments before they are ever certified for flight.&nbsp; And there should be not significant radiation effects on an explosive bolt in low earth orbit -- and even if there were those effects are testable on the ground.</p><p>It cannot possibly be the specific&nbsp;bolt that is being removed that has failed, since it has not been given the command to explode -- that happen during re-entry.</p><p>And if the thought is that the flight environment damages some but not all bolts (and they have not all failed) then recovery of a single bolt is still not particularly useful as a representative of a population.&nbsp; Further if that is the thought, then one would expect that the fleet would have been grounded some time ago.&nbsp; What happens if on some flight two or three bolts fail to fire ?</p> <div class="Discussion_UserSignature"> </div>

 

[CalliArcale]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>If that is the concern, then there really is something amiss.&nbsp; It is quite normal for components to be tested in shock and vibration fixtures far in excess of flight environments before they are ever certified for flight.&nbsp; And there should be not significant radiation effects on an explosive bolt in low earth orbit -- and even if there were those effects are testable on the ground.It cannot possibly be the specific&nbsp;bolt that is being removed that has failed, since it has not been given the command to explode -- that happen during re-entry.And if the thought is that the flight environment damages some but not all bolts (and they have not all failed) then recovery of a single bolt is still not particularly useful as a representative of a population.&nbsp; Further if that is the thought, then one would expect that the fleet would have been grounded some time ago.&nbsp; What happens if on some flight two or three bolts fail to fire ? <br /> Posted by DrRocket</DIV></p><p>It does seem like a long shot to me too.&nbsp; A manufacturing defect seems more likely to me, but that must either have been confined to the last two Soyuz or be too subtle to spot, since IIRC they've been inspecting pyrobolts from the same lot.&nbsp; But I suppose when you're desperate, any clue seems worth looking into.</p><p>As far as the fleet being grounded, failures like this have not been common.&nbsp; It could be that there is a very rare condition lurking in the design that chance alone caused to happen twice in a row, confounding engineers who are naturally looking for a commonality between Soyuz TMA 10 and Soyuz TMA 11. Look at Columbia; it was taken down by something that had happened on every single flight since the beginning, yet the fleet had never been grounded.&nbsp; That's the nightmare of every spacecraft engineer, of course -- a latent design defect. </p> <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>