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#140
by
JimO
on 29 Apr, 2008 18:22
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Blackstar - 29/4/2008 12:48 PM
I know Jim personally. I'm sure that if he has a problem with what I've written, he'll tell me so.
Problems? Heck, no, I go BEGGING him to do it.
As with almost all the arguments here, these clashes strike sparks that illuminate darkness.
We are the flint and steel, and as long as we're tough enough to take the heat and shock, we fulfill a bright function.
We do you think I titled my essay, "Seeing through the smoke and flame"...?
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#141
by
Namechange User
on 29 Apr, 2008 18:32
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clongton - 29/4/2008 1:14 PM
MrTim - 29/4/2008 1:54 PM
4. Neither the Challenger failure nor the Columbia failure would have been survived by a fall-back to a ballistic entry. Indeed, had the Soyuz suffered a hole in its TPS as large as the hole Columbia suffered, it would also have been destroyed.
I agree about the Challenger, but disagree about Columbia.
Of course it's academic at this point, but a jettisonable crew cabin, designed to withstand an emergency ballistic re-entry (like in one of the many original concept designs), would likely have survived the breakup of the orbiter in the upper atmosphere during re-entry. I am of the opinion that the crew could have survived, brused and shaken, but alive. The cabin would have landed intact in east-central Texas under a big parachute.
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.
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#142
by
Jonty McLee
on 29 Apr, 2008 18:38
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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?
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#143
by
rdale
on 29 Apr, 2008 18:41
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Jonty McLee - 29/4/2008 2:38 PM
I get the feeling this is the first and last time an Opinion Editorial is going to be on this site, right Chris?
I would hope not... Doesn't make sense to avoid keeping NSF as the premiere site when it comes to manned spaceflight.
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#144
by
Blackstar
on 29 Apr, 2008 19:05
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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. 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.
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#145
by
Firehawk153
on 29 Apr, 2008 19:14
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Just a space enthusiast here, but I see the ballistic entry as similar in purpose to the fire extinguisher that I bought for the house
Am I glad its available? Yes
Does it have the potential to save my my life? Yes
If a situation arose where it was needed, would I use it? Yes
However, would I welcome an event that would cause my actual use of my fire extinguisher? Hell no.
If an event occured that caused me to use my fire extinguisher would I investigate the circumstances surrounding that occurrence? Yes
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#146
by
on 29 Apr, 2008 19:19
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1. The journalism here is great. No, it isn't flight review, and the fact that it has nits is a total non issue. Get over it.
2. Agree with Chuck over Shuttle capsule - believe it was a conflicted response to budget and moving on to the next vehicle. Not focusing on finishing the current vehicle before understanding what to move on to. While we can rag on Russian weaknesses, lets not forget own own.
3. I see no issue with Blackstar's perspective on JimO - he's critical, which is what a good journalist wants/needs (separate issue is USING IT - JimO's writing to an audience, not necessarily Blackstar et al). And he can't always get the correct review in time.
4. I agree with MrTim that we have to look at the larger picture of multiple coordinated systems, many of which Soyuz does not and Shuttle does have. Basically, when something goes wrong with Soyuz, it jumps to "cannonball" mode and you cross your fingers. This neglects the possibility of managing the reentry dynamics with adaptive momentum budget and achieving a partially flying reentry, as well as coping with a chaotic/transient environment where parts are still attached that shouldn't be. Russians have always had this fatalism in design, where is you do the macho hard ride down, because space is a hard to survive environment. Its a holdover from Soviet times. They also are too cheap, not wishing (I suspect) to do the software engineering and test to actually finish Soyuz with the missing GNS components they've wrongly convinced themselves they can do without.
Ironically, both US and Russia screw up in identical ways - never wishing to finish just what they start.
Thank you again Chris for this fine location with all these fine people where you can discuss issues like this.
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#147
by
Lawntonlookirs
on 29 Apr, 2008 19:24
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Jonty McLee - 29/4/2008 2:38 PM
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?
I thought it was a great article and JimO has posted the facts as I have seen them. We will have to wait until the investigation is complete, and with the comments expressed in this thread, I am sure that NSF will be able to get the answers once they are released.
Keep up the editorial opinions as it puts a lot more insight into the discussion
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#148
by
MrTim
on 29 Apr, 2008 19:27
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clongton - 29/4/2008 11:14 AM
MrTim - 29/4/2008 1:54 PM
4. Neither the Challenger failure nor the Columbia failure would have been survived by a fall-back to a ballistic entry. Indeed, had the Soyuz suffered a hole in its TPS as large as the hole Columbia suffered, it would also have been destroyed.
I agree about the Challenger, but disagree about Columbia.
Of course it's academic at this point, but a jettisonable crew cabin, designed to withstand an emergency ballistic re-entry (like in one of the many original concept designs), would likely have survived the breakup of the orbiter in the upper atmosphere during re-entry. I am of the opinion that the crew could have survived, brused and shaken, but alive. The cabin would have landed intact in east-central Texas under a big parachute.
Chuck, this is headed a bit off-topic, but I think you are being a tad unfair to the orbiters here: Columbia suffered fatal TPS damage and any ballistic entry mode for Columbia would have solved nothing... just as equivalent TPS damage to a soyuz would have also doomed its occupants. To suggest a separable crew pod would be equivalent to suggesting an additional escape pod on soyuz. It's one bridge too far for either vehicle.
These are simply two very unique systems whose designers put into them all the safety they felt appropriate given all the constraints they faced. There is a lot of redundancy in an orbiter to cover many possibilities. In all but two of the flights the redundancy has been enough that we are used to seeing missions end with nice airplane-like landings and most people who see an orbiter land are never aware of any systems that failed while the vehicle was in flight. Unfortunately, there is no redundancy for a basketball-sized hole in the TPS of either an orbiter or a Soyuz. Had that soyuz taken too long to properly orient itself (something apparently left purely to chance) we would all be discussing a very different outcome and perhaps capsules would be looking a little less safe to people now (not something I am rooting for, I am happy to see anybody manage a safe return to Earth). My point to the earlier post is that neither system is perfect and I think the orbiter losses (which each killed a larger number of people and were each seen essentially live on TV) have given many a distorted view of the safety trade-offs and left some looking at the Soyuz capsule as superior (possibly because when its crews were lost, they were smaller crews and were not lost on live TV)
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#149
by
Jorge
on 29 Apr, 2008 19:27
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OV-106 - 29/4/2008 1:32 PM
clongton - 29/4/2008 1:14 PM
MrTim - 29/4/2008 1:54 PM
4. Neither the Challenger failure nor the Columbia failure would have been survived by a fall-back to a ballistic entry. Indeed, had the Soyuz suffered a hole in its TPS as large as the hole Columbia suffered, it would also have been destroyed.
I agree about the Challenger, but disagree about Columbia.
Of course it's academic at this point, but a jettisonable crew cabin, designed to withstand an emergency ballistic re-entry (like in one of the many original concept designs), would likely have survived the breakup of the orbiter in the upper atmosphere during re-entry. I am of the opinion that the crew could have survived, brused and shaken, but alive. The cabin would have landed intact in east-central Texas under a big parachute.
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.
The concept was dropped very early in the design process, before the shuttle looked like the shuttle. It would have been very heavy and, based on previous experience with escape capsules, would have provided only marginal improvement in survivability. There have been periodic proposals to retrofit the as-designed shuttle in this way, but none of the designs have been practical.
Not sure why Chuck agrees with Challenger and not Columbia. The aerothermal environment for crew module jettison was much more favorable with Challenger than it would have been with Columbia, and the odds of survivability correspondingly increased. Still not great, mind you, but better than Columbia.
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#150
by
Namechange User
on 29 Apr, 2008 19:29
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Blackstar - 29/4/2008 2:05 PM
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. 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.
That's kind of my point. If this was way back in the late 60's early 70's when all kinds of concepts for the shuttle were being studied, that's one thing. With the vehicle we have flying today lopping off the the forward section of the orbiter, and then somehow seperating the actual pressurized crew module, which now has to have it's own entry and recovery system, from the rest of the pointy end of the vehicle is exceedingly difficult.
It has been studied time and time again all with the same results. EXTREMELY expensive, no one sure if it will ever work, how to engineer it, the performance hit in terms of payload and CG, the very long lead time implementation, etc. It just doesn't make sense for this architecture and that is also a lesson to be learned but accept the risk for now.
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#151
by
on 29 Apr, 2008 19:32
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Could it be that the difference between Columbia and Challenger is with a capsule that didn't need to be jettisoned (e.g. you go into a hypersonic spin/tumble, and you seperate/stablize from that). Challenger would have required a more elaborate means to separate from the Shuttle?
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#152
by
Jim
on 29 Apr, 2008 19:34
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I don't think it was viable for entry or had TPS. It was only for ascent aborts and not orbital emergencies.
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#153
by
daj24
on 29 Apr, 2008 19:49
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rdale - 29/4/2008 2:41 PM Jonty McLee - 29/4/2008 2:38 PM I get the feeling this is the first and last time an Opinion Editorial is going to be on this site, right Chris?
I would hope not... Doesn't make sense to avoid keeping NSF as the premiere site when it comes to manned spaceflight.
I hope that there are more articles like Jim's if it is in regards to a timely topic. I do not know if Chris wants to loose too much of his editor's oversite but I'd bet that he would vet the piece before he publishes it. Chris would still drive the topic and the timing. I did not consider Jim's piece to be an Op Ed but an informational piece (except maybe at the very end). It did, however, generate a LOT of responses which is good for us and the site. I think that Alan Boyle and Tariq Malik and others would do interesting pieces. JMHO.
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#154
by
clongton
on 29 Apr, 2008 19:52
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The crew cabin of Challenger, I believe, hit the sea still basically intact, so the concept of a crew cabin remaining intact after the orbiter itself is torn apart around it is valid. I just don’t think Challenger would have had enough time, but Columbia was much higher with more time to impact. That’s my reasoning. Note that is an opinion. YMMV
As far as the TPS being breached on Columbia, it melted wing structure which caused the wing to be ripped off, which then turned the orbiter into the violent air/plasma stream and ripped it apart. That’s not much different than what happened to Challenger with the ET explosion. In both cases, the orbiter was torn apart by external forces. The difference is time to impact. That’s why I think the Columbia crew could have survived in a crew cabin that was designed to survive a ballistic re-entry.
I apologize for getting off topic here. Hopefully my explanation will suffice and we can let this off-topic side discussion go away.
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#155
by
Danny Dot
on 29 Apr, 2008 20:21
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OV-106 - 29/4/2008 2:29 PM
snip
That's kind of my point. If this was way back in the late 60's early 70's when all kinds of concepts for the shuttle were being studied, that's one thing. With the vehicle we have flying today lopping off the the forward section of the orbiter, and then somehow seperating the actual pressurized crew module, which now has to have it's own entry and recovery system, from the rest of the pointy end of the vehicle is exceedingly difficult.
It has been studied time and time again all with the same results. EXTREMELY expensive, no one sure if it will ever work, how to engineer it, the performance hit in terms of payload and CG, the very long lead time implementation, etc. It just doesn't make sense for this architecture and that is also a lesson to be learned but accept the risk for now.
I was working for NASA post Columbia and adding an emergency Mach 25 entry capsule to shuttle (or any vehicle like shuttle) would result in basically no payload capability.
Danny Deger
Read my story, "Houston, You Have a Problem" at
http://www.dannydeger.blogspot.com
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#156
by
clongton
on 29 Apr, 2008 20:29
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OV-106 - 29/4/2008 2:29 PM
snip
That's kind of my point. If this was way back in the late 60's early 70's when all kinds of concepts for the shuttle were being studied, that's one thing.
My comments were back in early design. Retrofitting the existing design is out of the question.
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#157
by
Blackstar
on 29 Apr, 2008 20:42
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clongton - 29/4/2008 3:29 PM
>>>That's kind of my point. If this was way back in the late 60's early 70's when all kinds of concepts for the shuttle were being studied, that's one thing.
My comments were back in early design. Retrofitting the existing design is out of the question.
It was studied post-Challenger as a possible retrofit. I've seen some of the studies, although I have no idea where I would find them again. Maybe they're in my files from five years ago. Anyway, the cost is huge and the payload hit is huge too. Not really practical.
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#158
by
janmb
on 29 Apr, 2008 21:08
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OV-106 - 29/4/2008 3:30 PM
For those thinking that ballistic mode is ok, would you want to ride it?
Absolutely not.
I just pointed out that it is a normal backup mode. That doesn't mean it's something you want to happen and of course it should be investigated.
Main priority has to be the separation issue tho, and if that proves unrelated to the root cause of the ballistic entries, finding that root cause comes second.
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#159
by
on 29 Apr, 2008 22:03
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Blackstar - 29/4/2008 3:42 PM clongton - 29/4/2008 3:29 PM >>>That's kind of my point. If this was way back in the late 60's early 70's when all kinds of concepts for the shuttle were being studied, that's one thing. My comments were back in early design. Retrofitting the existing design is out of the question.
It was studied post-Challenger as a possible retrofit. I've seen some of the studies, although I have no idea where I would find them again. Maybe they're in my files from five years ago. Anyway, the cost is huge and the payload hit is huge too. Not really practical.
The cost depended on the capabilities. Issue always is what contingencies you design for (and not). Plus lack of experience in this flight regime/environment.
Prefer to look at it as to what might have allowed survival rather than presuming all eventualities. In this specific Soyuz case, believe that while the issue will turn out to be separation / vehicle assembly/test, contingency for failed separation is insufficient.