The Real Soyuz Problem - Looking Past the Smoke and Flames

• #160 by sbt on 29 Apr, 2008 22:13
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  MrTim - 29/4/2008 6:54 PM(it's a sign that very bad things happened, and NOBODY should be comforted if the occupants walk away from it owing their lives to chance and accidents of physics (like part of the vehicle burning off in time for the capsule to orient properly))

  
  Not quite fair. It was not an entirely an 'accident of physics'. As per an earlier post in this thread the separation system was redesigned post Soyuz-5 to guarantee separation under thermal and aerodynamic loads to provide an additional level of redundancy.
  
  From what has been said the attachment system is possibly deliberately weak in tension and the pyrotechnic unlatching system definately has independent local thermal triggers as well as the remote electrical trigger from the control system.
  
  Rick
  
• #161 by Blackstar on 30 Apr, 2008 00:22
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  nobodyofconsequence - 29/4/2008  5:03 PM
  The cost depended on the capabilities. Issue always is what contingencies you design for (and not).  

  
  But even the cheapest option was expensive.
• #162 by on 30 Apr, 2008 01:27

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  Blackstar - 29/4/2008  7:22 PM  

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  nobodyofconsequence - 29/4/2008  5:03 PM The cost depended on the capabilities. Issue always is what contingencies you design for (and not).  

   But even the cheapest option was expensive.

  No sir.

  If all you wanted was Columbia/Challenger - yes you could.

  The real question is: would that be enough for the next crisis? No one would agree.

  Then we get project creep, ending up with a spacecraft within a spacecraft and unaffordable economics.

  But like Chuck said earlier, we are going off topic. If you like, start a thread and we'll fill it. Please just don't pick a fight pointlessly. My on topic point with the post was that Soyuz has too little contingency for failed separation and that the issue is cost.

  To your out of context edit of my post, software and testing is not too expensive. There. We are back on topic! 

• #163 by Lampyridae on 30 Apr, 2008 01:38
• A good article, and a thought-provoking read. I hadn't really thought about the Russians' approach to things with regards to ISS, but I think this latest Soyuz incident ought to be an important factor for the politcians dishing out policy and money. Personally, I think this makes the case for DIRECT all the more urgent. I don't think a COTS solution realistically will make the gap. I also wonder whether it's going to kickstart ACTS progress again?
• #164 by Blackstar on 30 Apr, 2008 01:53
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  nobodyofconsequence - 29/4/2008  8:27 PM
  
  

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  Blackstar - 29/4/2008  7:22 PM  

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  nobodyofconsequence - 29/4/2008  5:03 PM The cost depended on the capabilities. Issue always is what contingencies you design for (and not).  

   But even the cheapest option was expensive.

  No sir.

  If all you wanted was Columbia/Challenger - yes you could.

  The real question is: would that be enough for the next crisis? No one would agree. Then we get project creep, ending up with a spacecraft within a spacecraft and unaffordable economics. But like Chuck said earlier, we are going off topic. If you like, start a thread and we'll fill it. Please just don't pick a fight pointlessly. My on topic point with the post was that Soyuz has too little contingency for failed separation and that the issue is cost.

  To your out of context edit of my post, software and testing is not too expensive. There. We are back on topic!

  
  I read what you wrote twice and I still don't know what you mean.
  
  My point was that _any_ option for putting crew escape on the shuttle after it was built--and I've seen at least 3-4 different proposals, including "escape capsules" mounted on the upper deck--would have been expensive.  
  
  And if those capabilities had been included from the beginning, the vehicle would have paid a high weight and performance premium.
• #165 by Jorge on 30 Apr, 2008 02:11
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  clongton - 29/4/2008  11:18 AM
  
  

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  Jorge - 29/4/2008  11:11 AM
  
  

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  OV-106 - 29/4/2008  9:49 AM
  
  

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  clongton - 29/4/2008  9:36 AM
  
  

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  OV-106 - 29/4/2008  10:30 AM
  
  For those thinking that ballistic mode is ok, would you want to ride it?  

  No, I would not want to ride it. But if it is a choice between life and death, I wouldn’t hesitate to. Not for even a nano-second. The crew of Columbia would have loved to have had this choice.

  
  Apples and oranges Chuck.  I'm not even sure why you bring that up.

  
  To score debate points, natch.
  
  Ballistic mode would not have saved the Columbia crew; the TPS breach was fatal regardless of the profile flown.

  Shuttle’s backup mode is still an ‘actively controlled’ re-entry. That’s not what I was referring to. Soyuz backup assumes that there is no longer the ability to actively control the descent and simply spin stabilizes the crew capsule and drops it home. That’s the kind of “get me the hell out of here” last-ditch safety net that Soyuz has that Shuttle does not. Either Soyuz or Shuttle re-entering the atmosphere without active control would kill the crew. At least Soyuz has a last-ditch ace in the hole to get them down.

  
  And it's a good thing they have it, because they sure seem to need it often. Three times in the last eleven entries now.
  
  

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  That’s what I was referring to. Originally, the Shuttle crew cabin would have been jettisonable in such a situation, but that got traded away in the design phase for payload capacity. It was designed to make the same kind of emergency ballistic re-entry that Soyuz does.

  
  As Jim points out, the jettisonable capsule was designed for ascent and would not have had its own TPS.
  
  

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  in spite of the fact that Shuttle was originally designed to do the same thing.

  
  I do not believe this is correct. *Some* shuttle *proposals* were designed thusly, but not all of them did, and I don't believe any of the designs that could reasonably be described as "baseline" did. At least, my hasty re-scan of Jenkins did not turn up any. Definitely not any that had sufficient TPS to survive entry in the event of orbiter main body breakup.
  
  

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  I have lamented for years the trade that cancelled the ballistic re-entry of a jettisoned Shuttle cabin, and my lament about Columbia was to that end. Soyuz has that ability. Shuttle was “supposed” to have that ability but payload proved to be more important. In hindsight, a very bad design trade.

  
  I don't lament it at all. It would have cost a lot of money and weight and would have only marginally improved survivability during ascent, and not at all during entry. In hindsight, an excellent design trade.
  
  

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  As to the "scoring of debate points" – that was a cheap shot and not worth the electrons it took to put it on the thread.

  
  Fair enough, I apologize and I'll delete the offending comment.
• #166 by Jorge on 30 Apr, 2008 02:34
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  Spacenick - 29/4/2008  11:54 AM
  
  Well look at it this way:
  As a jet fighter pilot, your jet's engine might fail, then thats definitely a failure that needs to be addressed, however, if you have an ejector seat and that is executed, there is no point in lamenting that  landing on a parachute is not nominal, of cause it's not. But its a nominal _failure_ mode, don't blame the ejector seat for the loss of you engine. In the same way, you can't blame the ballistic mode for the separation failure, the only thing you can blame  the ballistic mode for is that nobody has to pay live assurances because the crew is alive.
  Ballistic entry is not a failure, it's the only way to survive the failure that had already happened and in this case there is no point in saying there might be a risk to it.

  
  I'm pretty sure that any fighter jet type that experiences three ejections in eleven flights, with the root cause unknown, would be grounded. Even with no fatalities.
  
  

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  Concerning the Shuttle comparison, I also think that it's a little bit like comparing apples and oranges, however, it's viable to note that a Soyuz definitely has a better history of bringing people back alive AFTER severe failures have occurred it siimply is more robust because it's less complex

  
  However, the *overall* record of the Soyuz of bringing the crew back alive is equivalent to that of the shuttle. (2 fatal accidents in 98 flights, vs 2 in 122 for the shuttle; 4 fatalities out of 237 person-trips vs 14 out of 733 for the shuttle, 87 consecutive successful crew returns for Soyuz (Soyuz 12 to Soyuz TMA-11) vs 87 for the shuttle (STS-26 to 113)).
• #167 by Jorge on 30 Apr, 2008 02:46
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  synchrotron - 29/4/2008  1:00 PM
  
  

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  MrTim - 29/4/2008  4:54 PM
  3. While Soyuz is much simpler than an orbiter (and some like to equate simplicity with safety), Soyuz needs to throw-off parts of itself during the re-entry process for a nominal flight and the vehicles seem to be accumulating a worrisome trend of failures in very mature (and therefore supposedly reliable) hardware required for this function. When I see failures of cutting-edge stuff, I worry about the design BUT when I see failures of mature stuff I worry about manufacturing, quality control, operator attentiveness, etc.
  

  
  Agreed.  But 'throwing off stuff' also has a specific function in this case.  Namely, protection of the TPS from launch- and orbit-based damage.

  
  That was not, of course, the *purpose* of designing it that way - the purpose was to minimize the mass of the descent module. And while it reduces the risk of TPS damage, it increases risk in other areas. Performing module separation in the critical period between deorbit and entry carries three risks, which have now either caused or been implicated (in the cases of TMA-10 and 11) in one Soyuz fatal accident and four close calls:
  
  1) The separation doesn't happen when it's supposed to (Soyuz 5, TMA-10, TMA-11 close calls)
  2) The separation happens when it's not supposed to (Soyuz TM-5 close call)
  3) The separation causes critical damage to another system (Soyuz 11 fatal accident)
  
  So it's not at all clear to me that the design trade is a net win in favor of module separation.
• #168 by Jorge on 30 Apr, 2008 02:53
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  Blackstar - 29/4/2008  2:05 PM
  
  

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  OV-106 - 29/4/2008  1:32 PM
  Where are these original concept designs?  If the shuttle then looks anything like the shuttle we have today, jettisoning the entire crew module is much more problematic than you are giving it credit.

  
  I'd have to look, but there have been a number of concept designs for jettisonable crew cabins for shuttle.  (I believe at least one of these evaluations was performed by the ASAP and may be available online somewhere.)  When I was with the CAIB I started collecting information on this (as well as information on early proposals for on-orbit tile repair).  We were considering making it at least a sidebar in the final report.  It never made it into the report because we ran out of time.

  
  I think General Deal mentioned it in his supplement. Would have to go back and look - I only have a hardcopy of volume 1.
  
  

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  Off the top of my head, I believe that the various capsule proposals resulted in at least 10-20K pound weight penalties.  Essentially, you ended up with a much reduced payload capability on the shuttle.

  
  The price tags were pretty gag-inducing too. The most expensive concept would have cost as much as two brand new orbiters just to retrofit the three existing ones.
• #169 by on 30 Apr, 2008 03:03

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  Blackstar - 29/4/2008  8:53 PM I read what you wrote twice and I still don't know what you mean.  My point was that _any_ option for putting crew escape on the shuttle after it was built--and I've seen at least 3-4 different proposals, including "escape capsules" mounted on the upper deck--would have been expensive.    And if those capabilities had been included from the beginning, the vehicle would have paid a high weight and performance premium.

  I have seen more than that before the Shuttle was built. And listened to number of different ideas to bring down the weight penalty to a minimum. Some of them quite radical and within budget. But this is not the thread for it.

  So lets drop the issue and keep the thread on target. Read the title at the top of the screen. It says "The Real Soyuz Problem". 

• #170 by Danderman on 30 Apr, 2008 03:08
• All in all, we might do best to remember the old axiom, "if it ain't broke .... ". After all, the backup system DID work.
  
• #171 by Chris Bergin on 30 Apr, 2008 03:29
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  Jonty McLee - 29/4/2008  7:38 PM
  
  

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  JimO - 29/4/2008  1:03 PM
  
  
  I stand well rebuked, and properly corrected.
  
  

  
  I get the feeling this is the first and last time an Opinion Editorial is going to be on this site, right Chris?

  
  We'll always run viable content that is of interest to our readership - as this one was.
• #172 by Chris Bergin on 30 Apr, 2008 03:30
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  nobodyofconsequence - 30/4/2008  4:03 AM
  So lets drop the issue and keep the thread on target. Read the title at the top of the screen. It says "The Real Soyuz Problem". 

  
  Agreed. This thread is running away with itself a bit.
• #173 by Jorge on 30 Apr, 2008 03:40
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  Danderman - 29/4/2008  10:08 PM
  
  All in all, we might do best to remember the old axiom, "if it ain't broke .... ".

  
  I think we might do better to throw out that old axiom and replace it with a new one. "Listen to the hardware."
  
  

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  After all, the backup system DID work.

  
  So did the secondary O-rings, for 24 flights. But on the 25th...
  
  
• #174 by Spacenick on 30 Apr, 2008 08:41
• You know what? In spite of all those different engineering styles  I think it's time for some European engineering style. Which will hopefully work out as asystem based on modular components with redundancy and an overall simple design like a European built Eurosoyuz with an ATV derived propulsion section, some more high tech than Soyuz and of cause hopefully more capability, like being able to use the propulsion section to transport modules to a station and the capability of unmanned flight and docking.
  I think the problem with the Russian style is, that their designs are great, but their tech is old and weak and their manufacturing hasn't got enough quality control, on the other hand the problem with the American style is their incapability to improve systems step by step. Either way, in the end it's only a question of money for all three.
  Don't let us only built Hummers and Ladas but also BMWs
• #175 by janmb on 30 Apr, 2008 10:21
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  Jim - 29/4/2008  1:58 PM
  
  I would like for those who disagree with the article to point out the errors

  
  I disagree with the general tone - not the technical content or conclusions.
  
  
  And again regarding the ballistic entry, I think everyone understands that it is not something you desire - it's merely pointing out that it is not a disaster. Yes, root cause should be found, but that needs to be very much secondary to investigating the separation issue, which related or not is a much more serious problem.
• #176 by mikers on 30 Apr, 2008 11:14
• Just re-read this opus.  It appears we cannot trust Russians, but, heck from the same article it follows that we cannot trust NASA (i.e. Americans) either.  I am entirely confused.
• #177 by synchrotron on 30 Apr, 2008 11:25
• Don't trust anyone over 30.  Or under 30.
  
  Seriously though, there has been a noticeable trend in engineering to judge performance based solely on cost and schedule performance.  I see it at work all the time.  People tend to fixate on the criteria that others use to judge them and the cumulative pressure on a team can lead to mistakes.  It's a human quality.  The effect is a little like going to the ballpark and watching the scoreboard instead of the game.  The scoreboard provides a function, but it's a measurement of how the function being performed, not the function itself.
  
  A similar effect frequently occurs at the highest levels of a public company too.  The leadership focuses on share price rather than on doing the job that is measured by the share value.
  
• #178 by mikers on 30 Apr, 2008 11:49
• Just curious, other than cost and schedule performance (which both are extremely important in my line of work, holding the client's requirements satisfaction constant), what metrics do you think are relevant here?  (I couldn't gather any from your post)  What is this "function itself" in terms of human spaceflight?  Good luck.
• #179 by clongton on 30 Apr, 2008 11:56
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  mikers - 30/4/2008  7:49 AM
  
  Just curious, other than cost and schedule performance (which both are extremely important in my line of work, holding the client's requirements satisfaction constant), what metrics do you think are relevant here?  (I couldn't gather any from your post)  What is this "function itself" in terms of human spaceflight?  Good luck.

  Caution: This is an innocent question, sort of like my earlier observation, that can potentially take the discussion way off target. Please answer within context.
  
  If this seems like it warrants its own thread, lets do that, because it could become very interesting indeed.