dmeyer@mips.csc.ti.com (Dane Meyer) (04/26/88)
Do any of you know why there isn't an escape system that could operate
during the SRB burn which would save the crew compartment in it's
entirity? Would it be too expensive, too complex, too heavy? It sure
seems like just having an extended pole to use when at 20,000 feet
flat and level doesn't cover many of the situations. I guess I was
thinking about an explosive charge to separate the entire compartment
and parachuting to safety, or something along that line. I know there
would be plenty of problems to solve, but I'm wondering what the
stoppers are.
Dane Meyer
ARPA/CSNET: dmeyer@mips.csc.ti.com
UUCP: {convex!smu, ut-sally, im4u, texan, rice}!ti-csl!dmeyerkwa1_ltd@ur-tut (Karl Wagenfuehr Ltd.) (04/27/88)
In article <47316@ti-csl.CSNET> dmeyer@mips.UUCP (Dane Meyer) writes: >thinking about an explosive charge to separate the entire compartment >and parachuting to safety, or something along that line. I know there >would be plenty of problems to solve, but I'm wondering what the >stoppers are. > COST! I know it sounds crass just stated like that, but think about it. The whole shuttle program, the whole space program, the whole world, operates on trading off benefits for inconveniences. There are certain safety features that can't be implemented on the shuttle because they would just cost way too much. Making the crew compartment be separable is an example of this. It would require a complete re-working of the shuttle, plus be expensive on its own, anyway. I think you're approaching the problem the wrong way. An escape system is just not cost effective. There are way too many complications (how are you going to keep them clear of the wings if you go out the side? If you go out the top, how to keep clear of the tail and oms pods? Then, don't forget the plumes from the SRBs which the ejecting crew would then have to somehow avoid. ANd so on); what should be considered are ways of making it less likely that an escape system will be needed. There will always be risks; the idea is to minimize those risks. Karl ['(] kwa1_ltd@tut.cc.rochester.edu
eugene@pioneer.arpa (Eugene N. Miya) (04/28/88)
>COST
You made an excellent summary (noting that you tried not to be too harsh).
What I might add also is that the costs are not just monetary. Escape
systems like pods are complex and heavy. Their records are not perfect.
Perhaps in later launch systems.
Note that the X-1 didn't have provisions for escape until late in it's
life. Nor for that matter commercial aircraft, helicopters, etc. Note: I
wore a parachute when soaring, but it does not function like a life vest
when I go sailing. Sport jumping is a completely different thing from an
emergency which is one reason why pilots are not really prepared for jumping
either. You must have some admiration for test pilots.
Another gross generalization from
--eugene miya, NASA Ames Research Center, eugene@ames-aurora.ARPA
soon to be aurora.arc.nasa.gov
at the Rock of Ages Home for Retired Hackers:
"Mailers?! HA!"
{uunet,hplabs,hao,ihnp4,decwrl,allegra,tektronix}!ames!aurora!eugene
"Send mail, avoid follow-ups. If enough, I'll summarize."jwm@stdc.jhuapl.edu (James W. Meritt) (04/28/88)
In article <47316@ti-csl.CSNET> dmeyer@mips.UUCP (Dane Meyer) writes: >Do any of you know why there isn't an escape system that could operate >during the SRB burn which would save the crew compartment in it's >entirity? Just to make a wild guess, I guess that it is sort of tough to get a three story building safely away from one of the biggest skyrockets in existence. Disclaimer: Individuals have opinions, organizations have policy. Therefore, these opinions are mine and not any organizations! Q.E.D. jwm@aplvax.jhuapl.edu 128.244.65.5
henry@utzoo.uucp (Henry Spencer) (05/03/88)
>Do any of you know why there isn't an escape system that could operate >during the SRB burn which would save the crew compartment in it's >entirity? Would it be too expensive, too complex, too heavy? All of the above: it would cost a lot to develop, especially with NASA doing it; it would be complicated and would probably require considerable redesign of the orbiter; it would be very heavy. It would also raise safety worries of its own. Remember that one of the reasons the pole was chosen over the tractor rockets was that storing rockets in the cabin is a significant safety problem. Military technicians are killed every year in ejection-seat accidents. > ... just having an extended pole to use when at 20,000 feet > flat and level doesn't cover many of the situations... Actually, it covers most of the situations that (a) happen after SRB shutdown and (b) do not involve major explosions or major structural failures. In such situations the preferred course of action is to get the bird under control and fly it back; the problem is that it can't always make it back and cannot be ditched or belly-landed safely. Hence the pole. -- NASA is to spaceflight as | Henry Spencer @ U of Toronto Zoology the Post Office is to mail. | {ihnp4,decvax,uunet!mnetor}!utzoo!henry
DMeyer@mips.csc.ti.com (Dane Meyer) (05/05/88)
I received quite a few responses to my original posting, both here and
e-mail -- all of them were very good. Thanks. I sent a copy of one
particularily thorough response to Ken Scofield, who was asking about
this in the first place, and he still had the following comments. Many
of you said that you just can't separate the entire shuttle from the
SRBs & Tank while the SRB's are firing ... and I believe you ... but
maybe someone could elaborate on the specifics. Please copy Ken
directly (and me if you don't post) on your response as he does not have
access to the net.
Thanks.
Dane Meyer (Texas Instruments, Dallas)
ARPA/CSnet: dmeyer@csc.ti.com
UUCP: {convex!smu im4u texsun pollux ihnp4!infoswx rice}!ti-csl!dmeyer
***********************************************************************
On the shuttle subject, the response you got was very thorough and inter-
esting, but one more possibility came to mind which wasn't discussed. Why
not just jettison the entire shuttle craft from the tank/booster assembly?
As I see it, the tank/booster assembly would just continue on its merry way
until it self-destructed, but the shuttle could glide off into the sunset
(sunrise?) and live happily ever after. Two arguments I've heard against
this are: The shuttle would break up due to aerodynamic forces, and/or it
would be burned up in the departing booster's firetail. Neither of these set
well with me, because (a) the shuttle is designed to re-enter the atmosphere
in excess of Mach 25, and (b) do so with skin temperatures of several thousand
degrees. So, what's the big problem? You may post this one, too, if desired.
Ken Scofield
ARPA: kas@hp-pcd.hp.com
UUCP: {convex, ames, im4u!rutgers, rice}!hp-pcd!hpcvic!kas
***********************************************************************brian@cbw1.UUCP (Brian Cuthie) (05/10/88)
In article <48048@ti-csl.CSNET> DMeyer@mips.csc.ti.com (Dane Meyer) writes: >I received quite a few responses to my original posting, both here and >e-mail -- all of them were very good. Thanks. I sent a copy of one >particularily thorough response to Ken Scofield, who was asking about >this in the first place, and he still had the following comments. Many [ken's comments:] >... Why >not just jettison the entire shuttle craft from the tank/booster assembly? >As I see it, the tank/booster assembly would just continue on its merry way >until it self-destructed, but the shuttle could glide off into the sunset >(sunrise?) and live happily ever after. Two arguments I've heard against >this are: The shuttle would break up due to aerodynamic forces, and/or it > >Ken Scofield Well, whoever told you that was exactly right. If you read the presidential commission's report on the Challenger you will see that the actual cause of the destruction of the craft was from aerodynamic forces rather than the large fire ball seen in the pictures. It seems that the large fire ball was mostly burning hydrogen, which had been dispersed when the tank ruptured. The force of that explosion was minimal compared to the aerodynamic forces seen by the shuttle when it suddenly was thrown sideways into the wind at several times the speed of sound. Looking at the pictures in the report reveals that the orbiter really broke into three major sections. It even looks as though the crew compartment is almost *completely* intact. It is best not to underestimate the force of wind at Mach > .5 :-) -brian -- Brian D. Cuthie uunet!umbc3!cbw1!brian Columbia, MD brian@umbc3.umd.edu
gordo@athena.mit.edu (Garet G Nenninger) (05/10/88)
cc: kas@hp-pcd.hp.com Ken, you are correct in saying that the shuttle is designed to re-enter at very high mach numbers, but that is going *forward*. The data I've seen says that the shuttle would separate at it's nose fitting but would be pinned against the two aft fittings. The resulting torque would slam the shuttle's nose away from the ET/SRB stack, so that the shuttle would have an angle of attack of about 90 degrees. That's definitely not something it was designed for. If you remember that Delta failure a few years back, when the rocket lost directional control and pitched over 20 degrees or so, the shroud was ripped off and it had begun to tear apart even before the range safety officer destroyed it. I'm not sure about the SRB plume problem, but keep in mind that the shuttle tiles are very brittle ceramic and that there is plenty of particulate matter in an SRB plume. (The brittleness of the tiles is the reason they cannot launch through rain--it would batter the tiles like a sandblaster.) The SRB plume is also very corrosive. While the tiles really aren't needed if the separation were low enough (hence no atmoshpheric heating), the only thing under them is a thin aluminum skin. It wouldn't take long for the plume to eat or burn through that if the tiles were blasted off.
henry@utzoo.uucp (Henry Spencer) (10/12/89)
In article <2430@hydra.gatech.EDU> ccsupos@prism.gatech.EDU (SCHREIBER, O. A.) writes: >That is the whole point of engineering: to design something from >the start to meet some functionalities and an escape system for >the propelled phase of the ascent should have been one of them >way back in 1972 when the design was chosen. It was studied at length. The Rogers Commission report cites a Rockwell study of escape systems, citing "separable crew compartment" at a weight penalty of 7+ tons and a development cost of several hundred million. Other relevant remarks: "All of these systems had limitations in their ability to provide successful escape, and all would require advance warning of an impending hazard from reliable data sources." "Only one of these [systems], the escape module, offers the possibility of escape during first-stage ascent. Its use would probably be practical only after [SRB] thrust termination..." "An additional weight penalty would result from the requirement to add mass in the rear of the orbiter to compensate for the forward shift in the center of gravity. Recent estimates indicate this could add as much as 30,000 pounds to the weight of the orbiter..." "The astronauts testifying before the Commission on April 3, 1986 agreed that it does not appear practical to modify the orbiter to incorporate an escape module..." Finally, it quotes Bob Crippen (STS-1 copilot): "I don't know of an escape system that would have saved the crew from the particular accident we just went through..." >I think this type of vehicle, without an escape system can never >be safe enough. Can you elaborate on why you think this? The men who know the hardware obviously disagree with you. >How much risk is the question How much risk FOR WHAT GAIN is the question. If *you* want to stay on the ground, nobody is going to march you on at gunpoint. -- A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
rogers@SRC.Honeywell.COM (Brynn Rogers) (10/12/89)
Who needs an escape rocket or a jettesonable crew compartment? Just have a Big parachute (or three or five) attached to the crew compartment. Then if we have 51L disaster again, the crew compartment has been separated for us, and we just throw the chute out. Granted that it may not be air or water-tight anymore, the chutes should enable astronauts (any who survived the initial explosion) to survive the water impact. About 1/4 :-). I think it could be made to work. (and not weigh too much) Brynn Rogers Honeywell S&RC rogers@src.honeywell.com home 612 874-7737
admiral%m-5@Sun.COM (Michael Limprecht SUN Microsystems Mt. View Ca.) (10/14/89)
In article <34577@srcsip.UUCP>, rogers@SRC.Honeywell.COM (Brynn Rogers) writes: > > Who needs an escape rocket or a jettesonable crew compartment? > Just have a Big parachute (or three or five) attached to the > crew compartment. Then if we have 51L disaster again, the crew > compartment has been separated for us, and we just throw the > chute out. Granted that it may not be air or water-tight anymore, > the chutes should enable astronauts (any who survived the initial explosion) > to survive the water impact. > > About 1/4 :-). I think it could be made to work. (and not weigh too much) > I think people are fooling themselves about an escape system for the shuttle. Most people don't realize the enormous forces and pressures the shuttle is under during the boost phase (The time the soilds are running). First off, nothing known on this planet at this time could have saved the Chalenger crew with the failure they had. How much time was there from main tank ignition to total breakup? Millisecounds? We know from the telemetry that Chalenger was having a rough ride. The shuttle was slightly pitched to one side probably due to the failing booster. But do you call an abort for that? For what reason? Even if they had decided to separate from the main tank (which they can't) the shuttle would have been ripped apart or severly damaged because the speeds at which they were traveling or by the exhuast from the boosters as they passed by. The same probably goes for any escape module that could have been ejected. The Chalenger loss of crew was not due to a lack of an escape system but a lack of safety measures/decisions/procedures taken throughout the project. My bitch is with the segmented booster idea in the first place. Launching in cold weather despite arguments from engineers, etc. With the time and limited money(sorry to say) that NASA has they should look at active ways of improving safety as opposed to passive ideas such as escape systems. Space travel is dangerous. People are going to be killed doing this and it's going to happen again. We should do the best we can to put that next time far in the future but let's not tie ourselves up trying to protect against everything. We'd never leave the ground. Mick
millard@eos.UUCP (Millard Edgerton) (10/14/89)
From article <126311@sun.Eng.Sun.COM>, by admiral%m-5@Sun.COM (Michael Limprecht SUN Microsystems Mt. View Ca.): > In article <34577@srcsip.UUCP>, rogers@SRC.Honeywell.COM (Brynn Rogers) writes: >> >> Who needs an escape rocket or a jettesonable crew compartment? >> Just have a Big parachute (or three or five) attached to the > Most people don't realize the enormous forces and pressures the shuttle > is under during the boost phase (The time the soilds are running). > STUFF DELETED*********************. > > Space travel is dangerous. People are going to be killed doing this and it's > going to happen again. We should do the best we can to put that next time > far in the future but let's not tie ourselves up trying to protect against > everything. We'd never leave the ground. > > Mick How many people die in auto accidents each year? Tens of thounands, half caused bye drinking, *NOT WATER*, and driving. Mike (above) is right. The Challenger crew knew the risks. With the same knowledge we should ALL quit buying and riding in cars. The irresponsible managers and congress and any one "who pressed for the launch" in time for the President's speech will eventually get their reward. Time wounds ALL HEALS! *************************************************************************** * Intelligent people talk about ideas. | Standard disclaimer(s) * * Average people talk about things. | Millard J. Edgerton, WA6VZZ * * Small people talk about other people. | millard@eos.arc.nasa.gov * ***************************************************************************
henry@utzoo.uucp (Henry Spencer) (10/15/89)
In article <126311@sun.Eng.Sun.COM> admiral%m-5@Sun.COM (Michael Limprecht SUN Microsystems Mt. View Ca.) writes: >Space travel is dangerous. People are going to be killed doing this and it's >going to happen again. We should do the best we can to put that next time >far in the future but let's not tie ourselves up trying to protect against >everything. We'd never leave the ground. A recent issue of Flight International had an interesting comment on this. The Europeans are wrestling with the issue of an escape system for their Hermes spaceplane (which is going to ride up on an Ariane 5, complete with two big SRBs -- segmented ones at that, sigh). The interesting part is that the potential Hermes astronauts are *against* the idea: they consider the risks acceptable and would rather see the mass go to something useful. -- A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
ccsupos@prism.gatech.EDU (SCHREIBER, O. A.) (10/15/89)
In article <1989Oct12.021826.7915@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >ability to provide successful escape, and all would require advance >warning of an impending hazard from reliable data sources." "Only one >of these [systems], the escape module, offers the possibility of escape >during first-stage ascent. Its use would probably be practical only >after [SRB] thrust termination..." "An additional weight penalty would They could have had the warnings had the SRB been instrumented like they were on the first flights. The escape system should be designed to function before SRB thrust termination. >weight of the orbiter..." "The astronauts testifying before the >Commission on April 3, 1986 agreed that it does not appear practical >to modify the orbiter to incorporate an escape module..." Finally, >it quotes Bob Crippen (STS-1 copilot): "I don't know of an escape >system that would have saved the crew from the particular accident >we just went through..." That is what anybody would say looking at the present design which was not from the start conceived to incorporate an escape system. It is obvious that one cannot patch an escape system one the tiles of the shuttle and that a redesign would be necessary. >>I think this type of vehicle, without an escape system can never >>be safe enough. >Can you elaborate on why you think this? The men who know the hardware >obviously disagree with you. The families of the victims, even without mentioning that of the teacher who was not an astronaut might agree with my statement. Why I think this way is because it is a vertical take off vehicle and a 3000 tons vehicle. The thrust put into play is thus very difficult to manage and puts the crew at greater risk than that of an ailiner or a fighter jet aircraft. Hence the need for an escape system. >How much risk FOR WHAT GAIN is the question. If *you* want to stay on the >ground, nobody is going to march you on at gunpoint. >megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu If you think that a 2.5 year delay in manned space operations is a GAIN, then of course the risk is ok. Still, NASA may not want in the future to take the responsibility of sending non astronauts with that kind of risk level, even volunteers like you. -- Olivier Schreiber (404)894 6147, Office of Computing Services Georgia Institute of Technology, Atlanta Georgia, 30332 uucp: ...!{allegra,amd,hplabs,seismo,ut-ngp}!gatech!prism!ccsupos ARPA: ccsupos@prism.gatech.edu
ccsupos@prism.gatech.EDU (SCHREIBER, O. A.) (10/15/89)
In article <2521@hydra.gatech.EDU> ccsupos@prism.gatech.EDU (SCHREIBER, O. A.) writes:
>
>>How much risk FOR WHAT GAIN is the question. If *you* want to stay on the
>>ground, nobody is going to march you on at gunpoint.
uunet!attcan!utzoo!henry henry@zoo.toronto.edu
If you think that a 2.5 year delay in manned space operations is
a GAIN, then of course the risk is ok. Still, NASA may not want
in the future
>to take the responsibility of sending non astronauts with that kind
--
Olivier Schreiber (404)894 6147, Office of Computing Services
Georgia Institute of Technology, Atlanta Georgia, 30332
uucp: ...!{allegra,amd,hplabs,seismo,ut-ngp}!gatech!prism!ccsupos
ARPA: ccsupos@prism.gatech.eduhenry@utzoo.uucp (Henry Spencer) (10/15/89)
In article <2521@hydra.gatech.EDU> ccsupos@prism.gatech.EDU (SCHREIBER, O. A.) writes: >>... Its use would probably be practical only >>after [SRB] thrust termination..." > >... The escape system should be designed >to function before SRB thrust termination. In case it hasn't penetrated yet: THIS IS VERY HARD. By far the simplest solution to that problem, which kills several other birds with the same stone, is to junk the damned roman candles and use liquid-fuel boosters. >>>I think this type of vehicle, without an escape system can never >>>be safe enough. >>Can you elaborate on why you think this? The men who know the hardware >>obviously disagree with you. > >The families of the victims, even without mentioning that >of the teacher who was not an astronaut might agree with my statement. Christa McAuliffe undoubtedly knew more about the safety issues than you or I; she volunteered. Note that her backup, who would be the person in line to fly the next such mission, has *not* withdrawn. The families of the Challenger astronauts are not astronauts, and do not necessarily understand the hardware. Moreover, I don't see any great post-Challenger exodus of astronauts from the program; I doubt that most astronauts would ignore their families' wishes in the matter. Note also my posting earlier today, observing that ESA's astronauts are *against* putting an escape system into Hermes. >Why I think this way is because it is a vertical take off vehicle and a >3000 tons vehicle. The thrust put into play is thus very difficult >to manage and puts the crew at greater risk than that of an ailiner >or a fighter jet aircraft... Have you figured out the thrust required for a 3000-ton airliner or fighter? It's less, but not an order of magnitude less. Vertical vs. horizontal takeoff simply does not make that much difference in the required thrust, especially for a supersonic aircraft. Concorde has thrust a couple of orders of magnitude greater than a typical private plane; which would you feel safer riding in? What matters is the competence of the engineers who design the engines, and the constraints put on them, not the size of the nozzles. As for comparative risks, have you looked at accident statistics for jet fighters? Any significant air force has to allow for steady attrition of its fighter force, even in peacetime -- they simply crash with some regularity. In 1986, far more people died in USAF jet fighters than in NASA space shuttles. >>How much risk FOR WHAT GAIN is the question... >If you think that a 2.5 year delay in manned space operations is >a GAIN, then of course the risk is ok. The 2.5 year delay was irrational, pure and simple. 2.5 years after an equally-ugly disaster hit Project Apollo, there were men walking on the Moon. I thought we were talking about technology, not politics. >Still, NASA may not want in the future >to take the responsibility of sending non astronauts with that kind >of risk level, even volunteers like you. NASA has never wanted to fly non-astronauts, ever, under any circumstances. They were delighted to have an excuse to put the "citizen in space" program on indefinite hold. They'd probably have done it even if the Challenger crew had survived. -- A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
ccsupos@prism.gatech.EDU (SCHREIBER, O. A.) (10/17/89)
In article <1989Oct15.035238.12688@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >In case it hasn't penetrated yet: THIS IS VERY HARD. By far the simplest Why do you use such an antagonistic way of expressing merely your opinion, not a fact? I thought you believed in that motto of yours: >A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology >megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu -- Olivier Schreiber (404)894 6147, Office of Computing Services Georgia Institute of Technology, Atlanta Georgia, 30332 uucp: ...!{allegra,amd,hplabs,seismo,ut-ngp}!gatech!prism!ccsupos ARPA: ccsupos@prism.gatech.edu
davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr) (10/17/89)
I wish the public could know just what the state of the astronauts was after the failure (a) before water impact and (b) after. Certainly after the breakup the cabin dropped subsonic, it would be worth thinking about a chute system at that point, something which isn't all that heavy. It would cover the case in which the cabin survived, as it seems to have after the fast burn and breakup. -- bill davidsen (davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen) "The world is filled with fools. They blindly follow their so-called 'reason' in the face of the church and common sense. Any fool can see that the world is flat!" - anon
henry@utzoo.uucp (Henry Spencer) (10/17/89)
In article <2544@hydra.gatech.EDU> ccsupos@prism.gatech.EDU (SCHREIBER, O. A.) writes: >>In case it hasn't penetrated yet: THIS IS VERY HARD... >Why do you use such an antagonistic way of expressing merely your opinion, >not a fact? ... Because it also appears to be the opinion of everyone who has studied the technical issues, including NASA, the astronauts, the NRC, ESA, and the Rogers Commission, and is consistent with what I know about ejection technology. That is, the weight of evidence very strongly suggests that it is a fact, not just a personal opinion. I am willing to listen to assertions to the contrary, provided they are backed up by a detailed technical explanation of why the weight of evidence is wrong. -- A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
rossh@umd5.umd.edu (Hollis "NeXT-Dood" Ross) (10/17/89)
In article <1155@crdos1.crd.ge.COM> davidsen@crdos1.UUCP (bill davidsen) writes: > I wish the public could know just what the state of the astronauts was >after the failure (a) before water impact and (b) after. Certainly after >the breakup the cabin dropped subsonic, it would be worth thinking about >a chute system at that point, something which isn't all that heavy. It >would cover the case in which the cabin survived, as it seems to have >after the fast burn and breakup. > >-- >bill davidsen (davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen) Here are my opinions on the above (I'm not a rocket scientest, but I play one on TV). Assuming that a system such as you suggest had been implemented, then it would have to work in the following way: 1) Seperation of the Crew compartment from the remains of the shuttle body. Some sort of explosives would be required for this. A reliable arming/disarming system would have to be used so that you didn't have any accidental misfires. 2) Once seperated, the crew compartment has to be "righted" so that the chute can deploy properly. It will probably be tumbling, and I'm sure you can't deploy a chute while you are turning end or end, and expect it to work. Some sort of Drouge (sp?) chute. 3) Deploy the Chute (The simple part). 4) Keep the crew compartment floating till help arrives, or Keep it afloat long enough for the conscious and mobile members of the crew to evac the wounded/unconscious members to rafts. 5) Most important part: Dodge tons of fallings debris during all of this. I remain skeptical of this solution. Other solutions such as Ejector seats aren't possible for the entire crew, from what I've heard. The only thing that could have saved the Challenger crew would have been Mgmt listening to the Engineers (In my opinion). Hollis Ross rossh@umd5.umd.edu /*****************************************************************************/ For a transcript of this posting, send $3 (Usenet dollars or I-Net Express only) to rossh@umd5.umd.edu or rossh@umdd (Bitnet). Taxes, tags, titles, destination charges, dealer prep and Usenet Flame Guards(C) extra. "Bo knows IBM 360 JCL"
phil@delta.eecs.nwu.edu (William LeFebvre) (10/17/89)
In article <126311@sun.Eng.Sun.COM> admiral%m-5@Sun.COM (Michael Limprecht SUN Microsystems Mt. View Ca.) writes: >Most people don't realize the enormous forces and pressures the shuttle >is under during the boost phase (The time the soilds are running). > >First off, nothing known on this planet at this time could have saved the >Chalenger crew with the failure they had. How much time was there from >main tank ignition to total breakup? Millisecounds?... The flight dynamics people probably saw something wrong as much as 10 seconds before the explosion, because the trajectory was wrong and the engines were gimballing (sp?) a very large amount to try to compensate. Of course, they probably didn't associate that with impending disaster. But even if they had known there was a problem, there wasn't a thing they could do about it until after SRB separation. It is acknowledged that the first two minutes of ascent---the time when the SRBs are burning---is the most critical and the most sensitive to disaster. If something goes wrong during that time, there is nothing that can be done. You just have to hope that you can ride it out until the SRBs are separated. You can't turn off a solid rocket, and in this case it is providing a very large percentage of the total thrust (so you can't just "eject" them at will, either). Note that the rescue system put in place post-Challenger (the "rod") can't even be used during SRB burn. So even if that was in place for Challenger, it would not have helped. William LeFebvre Department of Electrical Engineering and Computer Science Northwestern University <phil@eecs.nwu.edu>
phil@delta.eecs.nwu.edu (William LeFebvre) (10/17/89)
In article <2521@hydra.gatech.EDU> ccsupos@prism.gatech.EDU (SCHREIBER, O. A.) writes: >In article <1989Oct12.021826.7915@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >>ccsupos@prism.gatech.EDU (SCHREIBER, O. A.) writes: >>>I think this type of vehicle, without an escape system can never >>>be safe enough. >>Can you elaborate on why you think this? The men who know the hardware >>obviously disagree with you. > >The families of the victims, even without mentioning that >of the teacher who was not an astronaut might agree with my statement. I don't think they would. I think that the Challenger's families anger was primarily directed at the breakdown in MANAGEMENT, and NOT hardware. The families know that this is risky and that the shuttle will never be perfect or safe. But the fact that qualified and experienced engineers were adamantly saying "don't launch" and were being ignored because of political reasons is what angered them the most. I'd be pretty mad, too. William LeFebvre Department of Electrical Engineering and Computer Science Northwestern University <phil@eecs.nwu.edu>
henry@utzoo.uucp (Henry Spencer) (10/17/89)
In article <1155@crdos1.crd.ge.COM> davidsen@crdos1.UUCP (bill davidsen) writes: > I wish the public could know just what the state of the astronauts was >after the failure (a) before water impact and (b) after... Unless you really want all the morbid details, there is nothing secret about this. According to the medical/forensic report from the team led by Joe Kerwin (an MD/astronaut): 1. It is virtually certain that at least some of the crew were alive and conscious for at least a few seconds after the breakup. 2. It is highly likely that all of them were alive and more or less intact until water impact. 3. IF the cabin held pressure, and in particular IF none of the windows broke, they might have been conscious until water impact. If the cabin lost pressure, they would have become unconscious in a few seconds from hypoxia, and would not have recovered before impact. There is no evidence that they remained conscious, but there is no conclusive evidence that they didn't. It was not possible to determine definitely whether the cabin held pressure. 4. The water impact was severe and almost certainly instantly fatal. >Certainly after >the breakup the cabin dropped subsonic, it would be worth thinking about >a chute system at that point, something which isn't all that heavy. It >would cover the case in which the cabin survived, as it seems to have... Assuming that the chute system wasn't damaged in the breakup or obstructed by debris, that is. (Remember the solar array on Skylab -- it doesn't take that much obstruction.) Actually, the Challenger astronauts probably could have survived if they'd had pressure suits, oxygen, personal parachutes, and an escape hatch... which the astronauts now have. Getting out at subsonic speed with no engines running nearby is the easy part. -- A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
reb@squid.rtech.com ("REB - Take two checkpoints and call me in the morning") (10/17/89)
In article <126311@sun.Eng.Sun.COM> admiral%m-5@Sun.COM (Michael Limprecht SUN Microsystems Mt. View Ca.) writes: >In article <34577@srcsip.UUCP>, rogers@SRC.Honeywell.COM (Brynn Rogers) writes: >First off, nothing known on this planet at this time could have saved the >Chalenger crew with the failure they had. How much time was there from >main tank ignition to total breakup? Millisecounds? We know from the Wait a minute... I thought that the crew compartment landed relatively intact. reb Memories can't be bought. They reb@rtech.com reb%rtech.com@lll-winken.llnl.GOV can't be won at carnivals for h:861 Washington Westwood NJ 07675 201-666-9207 free. It took me years to get those souvenirs and I don't know how they slipped away from me-Prine/Goodman(?)
robina@tekig5.PEN.TEK.COM (Robin Adams) (10/18/89)
In article <5475@umd5.umd.edu>, rossh@umd5.umd.edu (Hollis "NeXT-Dood" Ross) writes: > In article <1155@crdos1.crd.ge.COM> davidsen@crdos1.UUCP (bill davidsen) writes: > > I wish the public could know just what the state of the astronauts was > >after the failure (a) before water impact and (b) after. Certainly after > >the breakup the cabin dropped subsonic, it would be worth thinking about > >a chute system at that point, something which isn't all that heavy. It > >would cover the case in which the cabin survived, as it seems to have > >after the fast burn and breakup. > > > >-- > >bill davidsen (davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen) > > Here are my opinions on the above (I'm not a rocket scientest, but I > play one on TV). Assuming that a system such as you suggest had been > implemented, then it would have to work in the following way: > > 1) Seperation of the Crew compartment from the remains > of the shuttle body. Some sort of ................ Ok. Some of your points were very good. So now maybe we can begin to condense and summarize. Some events (real or potential) which may have saved the total devastation of Challenger: o (Old) NASA Management listening to engineers regarding effects of the chill weather. o Substition of booster units (solid, liquid or hybrid) which could have been shut down at the earliest sign of malfunction (- Presumably the excessive engine gimballing in this case). o (Possibly:) An auto' deployable parachute attached to the crew compartment casing, as well as a device to arrest tumbling (- On the assumption all or some of the crew may have been alive after initial separation). I"m sure others can add to this list. It might seem a case of what's done is done. But the reality is that the worst possible accident has not yet happen- ed: The possibility that "one" of the solid rocket boosters may fail to ignite properly while still on the ground. We need to put pressure on NASA to make thatcorrection a priority in their new design issues. * |_____ * | |/ Robin * | Adams |_____|\ * |
santerel@clarke.cis.upenn.edu (Walter Santarelli) (10/18/89)
In article <1307@accuvax.nwu.edu> phil@delta.eecs.nwu.edu (William LeFebvre) writes: >separation. It is acknowledged that the first two minutes of >ascent---the time when the SRBs are burning---is the most critical and >the most sensitive to disaster. If something goes wrong during that >time, there is nothing that can be done. You just have to hope that you >can ride it out until the SRBs are separated. You can't turn off a solid >rocket, and in this case it is providing a very large percentage of the >total thrust (so you can't just "eject" them at will, either). > This is the reason I'm still amazed that we launch people on the current system at all. I believe the original concept called for a re-usable liquid fueled booster. Liquid fueled boosters offer the advantage that they can be throttled. SRB's can't. They just go. When I was an undergrad, I had a rocket propulsion professor who stated on more than one occasion that using SRB's for manned space flight was not smart safety-wise. In fact, before the Challenger accident, he stated predicted that the SRB's would be the cause of the first major accident. It's the system we've got now, might as well use it as safely as possible. Hopefully the next vehicle won't suffer from the budget cutter's axe in quite the same way. Blame Nixon, he halved the shuttle budget twice (at least). Walter Santarelli santerel@grad1.cis.upenn.edu Call your Congressman and Senators! Vote for more civilian space funding!
phil@delta.eecs.nwu.edu (William LeFebvre) (10/18/89)
In article <15596@netnews.upenn.edu> santerel@clarke.cis.upenn.edu.UUCP (Walter Santarelli) writes: >In article <1307@accuvax.nwu.edu> phil@delta.eecs.nwu.edu (William LeFebvre) writes: >>separation. It is acknowledged that the first two minutes of >>ascent---the time when the SRBs are burning---is the most critical and >>the most sensitive to disaster.... > >This is the reason I'm still amazed that we launch people on the >current system at all. I believe the original concept called for a >re-usable liquid fueled booster. Liquid fueled boosters offer the >advantage that they can be throttled.... And the disadvantage that they are much more volatile. The actual explosion that broke up the Challenger was the nearly instantaneous combustion of the liquid fuel, NOT the solid fuel (and if you want to be picky, the solid fuel wasn't even the initial technical cause---the segmented booster construction was). It's a matter of tradeoffs. I am of the impression that solid fuel gives greater force for the weight than liquid fuel does. Is that not true? >It's the system we've got now, might as well use it as safely as >possible. Hopefully the next vehicle won't suffer from the budget >cutter's axe in quite the same way. And hopefully it will be much safer. Let's hope future space shuttle/plane builders learn from the mistakes of the STS program! William LeFebvre Department of Electrical Engineering and Computer Science Northwestern University <phil@eecs.nwu.edu>
goldader@uhccux.uhcc.hawaii.edu (Jeff Goldader) (10/18/89)
In article <1321@accuvax.nwu.edu> phil@delta.eecs.nwu.edu (William LeFebvre) writes: >In article <15596@netnews.upenn.edu> santerel@clarke.cis.upenn.edu.UUCP (Walter Santarelli) writes: >> >>[...]I'm still amazed that we launch people on the >>current system at all. I believe the original concept called for a >>re-usable liquid fueled booster. Liquid fueled boosters offer the >>advantage that they can be throttled.... > >And the disadvantage that they are much more volatile. The actual >explosion that broke up the Challenger was the nearly instantaneous >combustion of the liquid fuel, NOT the solid fuel (and if you want to >be picky, the solid fuel wasn't even the initial technical cause---the >segmented booster construction was). It's a matter of tradeoffs. Well, if you want to be *real* picky, Challenger wasn't destroyed by any "explosion" at all. The shuttle was destroyed by the aerodynamic stresses caused by the orbiter pitching violently into the airstream after the breakup of the external tank. The way I remember the Rogers Commission report, the flame from the aft field joint sliced through the aft SRB attach strut, which simultaneuosly destroyed the aft dome supports of the ET's hydrogen tank. The SRB pitched around the forward attach strut, crushing the dome of the ET's LOX tank. The hydrogen was already gushing out of the ruined back of the tank, which gave a sudden thrust of some million pounds or so (can't remember exactly). Since the ET wasn't made to withstand this, and with the damaged forward section, it simply suffered complete structural failure. The orbiter found itself running through the air upside-down at Mach 4 with no thrust, pitched nose-down, and disintegrated. The actual explosive combustion of the hydrox wasn't all that bad; from what I remember, the orbiter could have survived that, but the aerodynamics of the separation killed it. Oh- correct me if I'm wrong, but wasn't the NASP funding killed altogether in this budget? Looks like we can forget about any shuttle replacement before 2010 or so. Jeff Goldader University of Hawaii uhifa.ifa.hawaii.edu Institute for Astronomy "So, Lonestar, now you see that Evil will always win- because Good is stupid." -The Dark Lord Dark Helmet, _SPACEBALLS_ Disclaimer: The opinions expressed herein are my responsibility alone. The University of Hawaii and the Institute for Astronomy neither support nor are in *any way* responsible for these opinions.
henry@utzoo.uucp (Henry Spencer) (10/19/89)
In article <1321@accuvax.nwu.edu> phil@delta.eecs.nwu.edu (William LeFebvre) writes: >I am of the impression that solid fuel gives greater force for the >weight than liquid fuel does. Is that not true? In general, correct. For one thing, it's easier to build solid motors in large sizes (i.e. high thrusts). For another, the average molecular weight of the exhaust is higher, which is bad for getting maximum velocity but good for getting maximum thrust. This is why they're so popular as strap-on boosters. -- A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
admiral%m-5@Sun.COM (Michael Limprecht SUN Microsystems Mt. View Ca.) (10/20/89)
In article <3838@rtech.rtech.com>, reb@squid.rtech.com ("REB - Take two checkpoints and call me in the morning") writes: > In article <126311@sun.Eng.Sun.COM> admiral%m-5@Sun.COM (Michael Limprecht SUN Microsystems Mt. View Ca.) writes: > >In article <34577@srcsip.UUCP>, rogers@SRC.Honeywell.COM (Brynn Rogers) writes: > >First off, nothing known on this planet at this time could have saved the > >Chalenger crew with the failure they had. How much time was there from > >main tank ignition to total breakup? Millisecounds? We know from the > > Wait a minute... I thought that the crew compartment landed relatively intact. > > reb My statement about time had to do with making the descision to abort and the factors involved with that. As to the main compartment landing relatively intact. The term "relatively" can mean a lot of things. Could the crew compartment have remained functional enough to deploy some type of escape system? The stress of a uncontrolled flight at mach 4+ probably left the crew compartment spining and breaking up until the shuttle slowed to subsonic speeds. I'm not sure that evacuation at this point would have been possible, hatches jammed shut, parts of shuttle everywhere. It's likely that the astronauts had some physical damage as well. How long from subsonic speeds to water impact? The point still remains that the Chalenger loss could have been avoided altogether with better decision making and not cutting corners. Mick
marcus@illusion.UUCP (Marcus Hall) (10/20/89)
In article <1307@accuvax.nwu.edu> phil@delta.eecs.nwu.edu (William LeFebvre) writes ] The flight dynamics people probably saw something wrong as much as 10 ] seconds before the explosion, because the trajectory was wrong and the ] engines were gimballing (sp?) a very large amount to try to ] compensate. Of course, they probably didn't associate that with ] impending disaster. But even if they had known there was a problem, ] there wasn't a thing they could do about it until after SRB ] separation. The trajectory deviation could easily have been due to unexpected wind shear (possibly combined with slightly more than normal SRB thrust asymmetry) which is NOT any reason to abort so long as the thrust vectoring is able to keep up. All aborts are considered higher risk (except perhaps abort to orbit) since they subject the STS system to very large stresses. The abort procedures are *supposed* to work. Nobody would actually want to try them out unless its absolutely necessary. So, if such indirect evidence is all you have that something's wrong, it probably isn't a wise choice to try an abort that *might* work (say even 50% chance of success) unless you know that your current situation is worse that that chance. BTW, does anybody know what the chances of the orbiter surviving the powered pitch over maneuver in the RTLS abort sequence is? Certainly if there was some possible abort worked out before SRB termination it would have even less chance than that. ] It is acknowledged that the first two minutes of ] ascent---the time when the SRBs are burning---is the most critical and ] the most sensitive to disaster. ... In article <15596@netnews.upenn.edu> santerel@clarke.cis.upenn.edu.UUCP (Walter Santarelli) writes: [ This is the reason I'm still amazed that we launch people on the [ current system at all. I believe the original concept called for a [ re-usable liquid fueled booster. Liquid fueled boosters offer the [ advantage that they can be throttled. SRB's can't. They just go. When [ I was an undergrad, I had a rocket propulsion professor who stated on [ more than one occasion that using SRB's for manned space flight was [ not smart safety-wise. In fact, before the Challenger accident, he [ stated predicted that the SRB's would be the cause of the first major [ accident. Actually, I believe that the landings (especially at Kennedy) are still considered the most likely cause of an accident. The SRBs were considered a relatively simple system that wasn't likely to fail (and thus the lack of an abort during SRB burn wasn't thought to be as big a risk as it is thought today). The SSME's are much more complicated and had some spectacular failures during development. Much more work went into reducing the risks that were precieved at the time. Although it was recognized that the SRBs were a critical item, it was not pushing any technologies significantly and was thought to be a problem well understood and the resources were spent on reducing other "more likely" failures. In hind sight, the SRBs were ignored too much, but at the time I'm sure it seemed like the proper way to spend the resources. -- marcus hall Time is an illusion marcus@illusion.UUCP Lunchtime doubly so - HHGTTG
bob@castle.ed.ac.uk (Bob Gray) (10/23/89)
In article <1989Oct14.220418.5339@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >A recent issue of Flight International had an interesting comment on this. >The Europeans are wrestling with the issue of an escape system for their >Hermes spaceplane (which is going to ride up on an Ariane 5, complete with >two big SRBs -- segmented ones at that, sigh). The interesting part is According to the latest news the developers, CNES the French centre for space studies, have decided to re-design Hermes to provide ejection seats for the three crew members. This will delay the first flight from 1995 to 1998. Starts to sound a familiar story..... Bob.
petej@phred.UUCP (Pete Jarvis) (10/24/89)
In article <1307@accuvax.nwu.edu> phil@delta.eecs.nwu.edu (William LeFebvre) writes: >total thrust (so you can't just "eject" them at will, either). > I read somewhere that that there is a quick-disconnect procedure for the SRB's. Once initiated, it then takes a few seconds for it to occur. There is a manual SRB disconnect switch on the center console between the Commander and Pilot, but I don't know the criteria for its use. Peter Jarvis ------- Physio-Control, Redmond, WA.
henry@utzoo.uucp (Henry Spencer) (10/24/89)
In article <409@illusion.UUCP> marcus@illusion.UUCP (Marcus Hall) writes: >BTW, does anybody know what the chances of the orbiter surviving the powered >pitch over maneuver in the RTLS abort sequence is? ... Nobody has tried it, so we don't know for sure. The astronauts are reputed to be unhappy about the possibility of having to fly that maneuver. (For those who aren't up on this, a Return To Launch Site abort involves doing a U-turn at hypersonic speeds.) -- A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
goldader@uhccux.uhcc.hawaii.edu (Jeff Goldader) (10/25/89)
In article <2815@phred.UUCP> petej@phred.UUCP (Pete Jarvis) writes: > >I read somewhere that that there is a quick-disconnect procedure for the >SRB's. Once initiated, it then takes a few seconds for it to occur. There >is a manual SRB disconnect switch on the center console between the Commander >and Pilot, but I don't know the criteria for its use. > The "quick-disconnect" procedure and the associated manual sep switches for the SRBs are for use if the SRBs fail to separate automatically at the end of their burn. The system is not intended as a way to sep a malfunctioning SRB from the shuttle. As has been mentioned here e**n times before, bad, bad things would happen if a SRB separated before it should, and, as you might be able to imagine, bad things would also happen if a spent SRB failed to separate. Jeff Goldader University of Hawaii goldader@uhccux.uhcc.hawaii.edu Institute for Astronomy "So, Lonestar, now you see that Evil will always win- because Good is stupid." -The Dark Lord Dark Helmet, _SPACEBALLS_ Disclaimer: The University of Hawaii and the Institute for Astronomy neither support nor are in *any way* responsible for these opinions.
kas@hpcvia.CV.HP.COM (ken_scofield) (10/26/89)
>In article <409@illusion.UUCP> marcus@illusion.UUCP (Marcus Hall) writes: >>BTW, does anybody know what the chances of the orbiter surviving the powered >>pitch over maneuver in the RTLS abort sequence is? ... > ^^^^^^^^^^ > ... >(For those who aren't up on this, a Return To Launch Site abort involves >doing a U-turn at hypersonic speeds.) >-- ^^^^^^ >A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology >megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu OK, here's a question I've been wanting to ask for a long time: Why is the (apparently) preferred manuever a "pitch over"? I assume that the manuever is a half-inside-loop, such that the initially upside-down shuttle comes out of the bottom of the loop right-side-up and heading back toward KSC. This seems fairly simple in principle, but isn't there going to be a loss of gobs and gobs of (I assume) precious altitude? Why not do a 180-degree roll first (to get right-side-up), then turn like any ol' normal airplane (well, sorta :-) )? The altitude loss would be much less, and the chances of getting back to KSC would be improved. And one last question: Is the ET still attached during RTLS abort, or is it dropped first? Ken Scofield Hewlett-Packard, ICO 1020 NE Circle Blvd. Corvallis, OR 97330 Phone: (503)757-2000 ucbvax!hplabs!hp-pcd!kas kas@hpcvia.CV.HP.COM Cute Disclaimer: Nobody ever listened to me before, so why start now?
henry@utzoo.uucp (Henry Spencer) (10/26/89)
In article <23280001@hpcvia.CV.HP.COM> kas@hpcvia.CV.HP.COM (ken_scofield) writes: >>(For those who aren't up on this, a Return To Launch Site abort involves >>doing a U-turn at hypersonic speeds.) > > OK, here's a question I've been wanting to ask for a long time: Why is the > (apparently) preferred manuever a "pitch over"? > > I assume that the manuever is a half-inside-loop, such that the initially > upside-down shuttle comes out of the bottom of the loop right-side-up and > heading back toward KSC. This seems fairly simple in principle, but isn't > there going to be a loss of gobs and gobs of (I assume) precious altitude? I *think* the answer is "you're thinking aircraft, when you should be thinking rocket". This maneuver is being done at extremely high altitude by a vehicle with powerful rocket engines still operating. Any loss of altitude can be fixed in seconds by pitching up a bit afterwards. > And one last question: Is the ET still attached during RTLS abort... Yes. RTLS involves *thrusting* backward, not just doing a gliding U-turn. (Again, rocket, not aircraft.) The ET is attached and the main engines are still firing. -- A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu