wab@yoda.Rational.COM (Bill Baker) (03/16/91)
In article <1991Mar13.045435.3817@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >[Transliterated to lower case to make it at least semi-readable! Please >don't post long articles in SCREAMING UPPERCASE.] > >In article <0566B3896080344E@splava.cc.plattsburgh.edu> LONGWJ@SPLAVA.CC.PLATTSBURGH.EDU writes: >>4. more morbid curiosity...since the challenger explosion has there been any >>effort to redesign the shuttle orbiter so that the crew cabin could be used in >>an emergency splashdown? maybe something like the present crew cabin with its >>own parachute system and heat sheild? ... > >The idea is not ridiculous, but it would require massive redesign, and >the extra mass might well wipe out the shuttle's payload entirely. The >ESA designers working on Hermes came to the same conclusion as NASA: >bringing the whole cabin down is difficult and costly, and probably >not worth it. (ESA has gone for ejection seats on Hermes, over the >protests of the astronauts, who think the correct solution is not >to fit an escape system at all.) I've wondered about this since the post-Challenger redesign began. Given that the cabin is designed to be much more robust than the rest of the orbiter and given that the cabin of the Challenger did emerge from the initial break-up somewhat intact and some circumstantial evidence that the crew survived the break-up if not the impact: Why not include some rudimentary survival system that might save the cabin after a high to medium altitude catastrophic failure? It might be nothing more than a hellacious parachute built into the rear wall of the cabin, deployed only by command of one of the "pilots." This presumes someone surviving to hit the button, but this may have been the case with the Challenger and if a large parachute had been deployed from the cabin at the top of its ballistic arc after break-up wouldn't it have had a reasonable chance of maintaining structural integrity during a parachute-aided landing? Presuming the crew survived the blast and other effects (I suppose high-gee spin might leave you fatally concussed or disoriented), couldn't they reasonably expect to survive such a landing inside the cabin? Of course, if you were landing in water you might as well have died in the explosion, but... That's a lot of caveats, but actually wouldn't this scenario cover most of the worst contingencies? The Challenger break-up is about the most catastrophic possible scenario, no? And the cabin survived whole (sort of, maybe), so there is a likelihood of cabin survival in the worst of circumstances (and therefore in all the less catastrophic instances, too). Now, what are the floor and ceiling of practical cabin survival with some sort of parachute detente system? Too low and it has no time to deploy. Too high and, I guess, it's destroyed by reentry effects (just to define a broad rubric). Wouldn't this actually be a pretty wide spread? From how many nautical miles up could the cabin theoretically descend and the crew survive if it maintained pressure and had a robust detente system. It would probably take a series of drogue ribbons and 'chutes ala Apollo reentry, but it doesn't seem technologically unreasonable. Wouldn't such a "window" actually comprise the majority of time in which the shuttle is likely to fail? Extend this further and accept more (but perhaps still minimal) increases in systems complexity, cost, and weight: Design a system to separate the cabin in the case of non-catastrophic failure (my bet for the next shuttle crash: A couple turbo-pumps fail in mid-ascent, the shuttle loses two engines and can't make orbit). Instead of going down the pole with a chute and a prayer or trying to separate and land the shuttle, include an ejection "ring" at the juncture of the cabin and the rest of the orbiter body that would blow the cabin away from a doomed stack, sort of the way that stages separate in multi-stage rockets. Obviously, a survivable separation at high speed is more than a minor problem, but it's better than nothing. Include a backup computer inside the cabin that monitors altitude, change of attitude, telemetry status, etc. and matches it against a data profile of likely system failure (e.g., We're a hundred thousand feet up, we're experiencing extremely high roll rates, I'm receiving no ground telemetry, no data from the rest of the orbiter, and all of these things have happened simultaneously. Conclusion: We've blown up). Have it control firing the emergency separation charges, chutes, etc. in case the crew is unconscious but not dead (e.g., Challenger). Maybe it all works and they survive to have grandchildren. Even over water, maybe they ride cabin-with-parachute down to a reasonable altitude and then jump with their own 'chutes (the latter part is already an accepted escape method from the shuttle). At least they'd have a chance for, perhaps, a small tradeoff in payload. Even as wacky as these scenarios seem, the likelihood that we are going to watch more cabins coming down whole seems pretty good. NASA's saying something like 1 out of 80 shuttle flights will suffer a major failure, and it seems to me that most of these will be pad failures, mid-ascent failures, and reentry failures. In the last two catgories I can well imagine that an orbiter will again go to pieces and leave the fly-boys hurtling to Earth in a titanium bathysphere.
adamsd@crash.cts.com (Adams Douglas) (03/20/91)
If you're going to start mounting pyro-sep devices all over the orbiter,
then the logical place to do it would be on the ET mounts. The reason there
is no escape protocol when the SRBs are still attached is because all
simulations show that a "normal" ET sep triggered at such a time would
cause the orbiter to hang up on the aft attach points, flip over and break up.
Remember, the ET explosion did _not_ cause Challenger to break up, it was
being flopped around in a Mach 5 airflow that accomplished that.
I, personally, would rather try to ditch or land with a reasonaly intact
orbiter than a front cabin.
--
====================================================================
Adams Douglas
3206 Raintree Circle -sometime I'll think of a good quote for here-
Culver City, CA 90230
crash!adamsdhenry@zoo.toronto.edu (Henry Spencer) (03/21/91)
In article <923@igor.Rational.COM> wab@yoda.Rational.COM (Bill Baker) writes: >... Why not include >some rudimentary survival system that might save the cabin after a >high to medium altitude catastrophic failure? It might be nothing >more than a hellacious parachute built into the rear wall of the >cabin... The problem with this is that it's useful only if the separation of the cabin is relatively "clean". The Challenger cabin, in the tracking photos, had all sorts of cabling and other junk trailing behind it. Any of that could easily have entangled a parachute. If you start trying to ensure clean separation, you get into a lot more complexity, including a lot of pyrotechnics that are dangerous to crew and maintenance workers even if not used. The weight starts to add up quickly, too. It's not an accident that ESA rejected an escape-capsule design for Hermes. -- "[Some people] positively *wish* to | Henry Spencer @ U of Toronto Zoology believe ill of the modern world."-R.Peto| henry@zoo.toronto.edu utzoo!henry
wab@eclipse.Rational.COM (Bill Baker) (03/21/91)
In article <8097@crash.cts.com> adamsd@crash.cts.com (Adams Douglas) writes: >If you're going to start mounting pyro-sep devices all over the orbiter, >then the logical place to do it would be on the ET mounts. The reason there >is no escape protocol when the SRBs are still attached is because all >simulations show that a "normal" ET sep triggered at such a time would >cause the orbiter to hang up on the aft attach points, flip over and break up. >Remember, the ET explosion did _not_ cause Challenger to break up, it was >being flopped around in a Mach 5 airflow that accomplished that. This is exactly the point I was making. Excluding pad failures, the most likely periods for catastrophic failures are low ascent and reentry. Now, there may be a zillion things that could go wrong, but the most likely result of any of them is breakup of the orbiter due to aerodynamic effects. Given this and including the fact that (according to everything I read at the time of the Challenger crash) the crew cabin is built much stronger than the rest of the orbiter, the Challenger scenario (breakup, cabin surviving intact) is more likely the model for future failures than the exception. All scenarios involving orbiter separation from the stack have a low applicability because, most probably, there won't be an orbiter or a stack left. It seems like NASA came to the same conclusion that the orbiter is very unlikely to survive intact from most failures, but their reply is to assume that orbiter breakup equals immediate crew death. So they say, essentially, "If the orbiter does survive in one piece, here's a big pole to slide out of it on." Is there any other modern aircraft whose entire crew survival system depends on a fire pole? As I said, it seems to me that if we continue to lose a shuttle every few years (1 in 78 chance of major failure with at least ten launches a year equals an expensive fireworks demo at least once a decade) we are going to see a lot of crew cabins surviving like the Challenger's. Spinning extremely fast and on a ballistic road to hell, sure, but still surviving the initial breakup mostly intact. Next time we may know for sure if a crew can survive this kind of failure, and if the American public is treated to three minutes of screams as they plunge to their doom NASA engineers will go down as the worst fools in history. >I, personally, would rather try to ditch or land with a reasonaly intact >orbiter than a front cabin. This seems to be the sentiment of most pilots, and in my opinion the shuttle was built as a plane instead of as reentry capsule with lift properties. Tom Wolfe covers the philosphical differences between the pilot/engineer camps in "The Right Stuff" but it boils down to this: A plane has a pilot and a capsule has a test subject. Pilots are in control and they expect their machines to be built for them to make heroic recoveries instead of punching out. Pilots hate to punch out. I'm sure that on the first shuttle launch Truly was thinking to himself, "The hell with the ejection seats. If the shit hits the fan, I'm shutting down the computers and putting this baby down by the seat of my pants." So instead of thinking of the crew cabin as a separatable capsule (which it wasn't designed to be, I know), they think in terms of saving the "plane" or at least wrestling it into a glide so they can slide down the pole and parachute, even though it's highly unlikely for a scenario allowing these heroics to occur. In fact, I think the pole system (if you can call it a system) was designed to create a scenario for heroics. Unless the computer-controlled flight software has an emergency stall profile included, the orbiter must be manually controlled to get it into a flight path from which it would be safe to bail out. You certainly couldn't bail at supersonic speeds, and I imagine you'd pretty much have to be low subsonic and in a reasonably flat attitude to jump with a chance of surviving. This means that someone's got to fly the plane while everyone else jumps. Shuttle Commander: I'll get this hummer flat and slow if it's the last thing I do. You'll only have a few seconds so when you hear my signal jump and don't look back. Crew Member (preferably some sweet-faced Christa McAuliffe type): But what about you? You'll never make it to the hatch before the orbiter dives out of control. SC: 'Tis a far, far better thing I do.... So, as has been said in this group before, the pole system is more a political showpiece than a viable survival system. I think you could say the same about the flying basket and armored personal carrier system for escaping from the shuttle on the pad. Any pad failure so serious that the crew has to escape quickly is most likely going to result in an instantaneous fireball. Planning for the slim chance that there would be time to escape isn't worth the time and money, but NASA built the basket anyway. Why? Not because they want to cover every risk and damn the money. No, because they've already thought of the implications of the following scenario with no escape system: Mission Control: T minus 7, engine start...T minus 4, turbopump failure! Uncontrolled propellant venting! SC: Oh Jesus.... MC: Fire on the pad! Abort launch! Main engine shutdown! Crew members: Fire? There's a fire in the engines! Oh my God! MC: ET valves are shut but we are still losing pressure in the hydrogen tank. SC: Damn turbopump's holed the tank. Mission Control, can we go down the elevator? MC: Negative, the pad base is totally involved with flame. [This goes on for what seems like forever (but is probably less than a minute) with lots of screams and prayers. Then the fire reaches the ET and boom!] MC: Obviously a major malfunction.... Following which a grim Congressional committee plays the transcripts for the current flunky in charge of NASA and NASA safety engineers spend the rest of their lives hawking pencils. I'm still waiting for one of those exhaustive Henry Spencer rebuttals to my original posting.
bdietz@sdcc13.ucsd.edu (Jack Dietz) (03/21/91)
In article <940@igor.Rational.COM> wab@eclipse.Rational.COM (Bill Baker) writes: >I'm sure that on the first shuttle launch Truly was thinking to >himself, "The hell with the ejection seats. If the shit hits the fan, >I'm shutting down the computers and putting this baby down by the seat >of my pants." Uh, Truly (and Engle) were on STS-3. You're probably thinking of Cdr. John Young. >I'm still waiting for one of those exhaustive Henry Spencer >rebuttals to my original posting. Sounds like fun. He _does_ seem to spend quite a bit of time in `postnews', doesn't he? =) -- Segal's Law: | Jack Dietz A man with one watch always knows what time it is. | (bdietz@ucsd.edu) A man with two watches is never sure. | Bandwidth Bandit
fiddler@concertina.Eng.Sun.COM (Steve Hix) (03/22/91)
In article <940@igor.Rational.COM> wab@eclipse.Rational.COM (Bill Baker) writes: > >I'm sure that on the first shuttle launch Truly was thinking to >himself, "The hell with the ejection seats. If the shit hits the fan, >I'm shutting down the computers and putting this baby down by the seat >of my pants." Must have been in his dreams...wasn't the first flight with Crippen and Young? (Who flew the first glide test?) -- ------------ The only drawback with morning is that it comes at such an inconvenient time of day. ------------
maschino@gn.ecn.purdue.edu (Mr. Vegomatic, 1988) (03/22/91)
In article <10245@exodus.Eng.Sun.COM>, fiddler@concertina.Eng.Sun.COM (Steve Hix) writes: > In article <940@igor.Rational.COM> wab@eclipse.Rational.COM (Bill Baker) writes: > > > >I'm sure that on the first shuttle launch Truly was thinking to > >himself, "The hell with the ejection seats. If the shit hits the fan, > >I'm shutting down the computers and putting this baby down by the seat > >of my pants." > > Must have been in his dreams...wasn't the first flight with Crippen and > Young? That's correct. > > (Who flew the first glide test?) > Got me. > > -- > ------------ > The only drawback with morning is that it comes > at such an inconvenient time of day. > ------------ Marc (maschino@gn.ecn.purdue.edu)
gregc@cimage.com (Greg Cronau) (03/23/91)
In article <940@igor.Rational.COM> wab@eclipse.Rational.COM (Bill Baker) writes: >I'm sure that on the first shuttle launch Truly was thinking to >himself, "The hell with the ejection seats. If the shit hits the fan, >I'm shutting down the computers and putting this baby down by the seat >of my pants." So instead of thinking of the crew cabin as a I've got 2 little problems with this: 1.) If Truly was on the first shuttle mission, he was hiding somewhere in the equipment bay. The first mission was Young/Crippen. 2.) If you shut down the computers, then you had better eject, because you are flying a *rock* at that point! Without the computers, there's no way to get the signals from the pilots controls to the control surfaces! gregc@cimage.com
petej@phred.UUCP (Peter Jarvis) (03/26/91)
In article <10245@exodus.Eng.Sun.COM> fiddler@concertina.Eng.Sun.COM (Steve Hix) writes: > >Must have been in his dreams...wasn't the first flight with Crippen and >Young? >(Who flew the first glide test?) > Fred Haise (from Apollo 13) flew the first Enterprise flight. Peter Jarvis....
wab@rutabaga.Rational.COM (Bill Baker) (03/26/91)
In article <1991Mar23.094700.14237@cimage.com> gregc@dgsi.UUCP (Greg Cronau/10000) writes: >In article <940@igor.Rational.COM> wab@eclipse.Rational.COM (Bill Baker) writes: >>I'm sure that on the first shuttle launch Truly was thinking to >>himself, "The hell with the ejection seats. If the shit hits the fan, >>I'm shutting down the computers and putting this baby down by the seat >>of my pants." So instead of thinking of the crew cabin as a > >I've got 2 little problems with this: >1.) If Truly was on the first shuttle mission, he was hiding somewhere in >the equipment bay. The first mission was Young/Crippen. I post two long pieces on the shuttle survival system and almost the only response is, "It wasn't Truly it was Crippen." Alright, it was Crippen! Jeez.... >2.) If you shut down the computers, then you had better eject, because you >are flying a *rock* at that point! Without the computers, there's no way >to get the signals from the pilots controls to the control surfaces! > >gregc@cimage.com Same thing. If it makes the nitpickers happy, substitute the word "overriding" for the phrase "shutting down." The intent was perfectly clear. For God's sake, I hope the future of the net isn't typical of this useless pedantery. I still say that NASA is shooting itself in the foot with no real crew survival system. Their rationale, and this applies to a lot of other shuttle systems as well, is that the likelihood of failure over time isn't worth the trouble. Yet this argument assumes a low number of flights annually. Fewer flights=less risk of failure over the lifetime of the shuttle program. More flights=greater risk. So essentially NASA is betting that shuttle use *won't* increase; it's betting against its own favorite launch system and predicating a lot of design features on that assumption. Isn't NASA supposed to be ambitious? Even with a new heavy lifter, construction and maintenance of the Space Station, a Mars mission, shuttle repair/retrieval of satellites, launching probes, various science missions, all add up to more than ten flights a year over the next 30 years. Either NASA's being pessimitic about how often the shuttle will fly or else cavalier with the lives of astronauts.
shafer@skipper.dfrf.nasa.gov (Mary Shafer) (03/26/91)
In article <3363@phred.UUCP> petej@phred.UUCP (Peter Jarvis) writes: In article <10245@exodus.Eng.Sun.COM> fiddler@concertina.Eng.Sun.COM (Steve Hix) writes: > >Must have been in his dreams...wasn't the first flight with Crippen and >Young? >(Who flew the first glide test?) > Fred Haise (from Apollo 13) flew the first Enterprise flight. It wasn't a solo flight. Fred Haise (formerly a Dryden test pilot) and Gordon Fullerton (now a Dryden test pilot). Fitz Fulton commanded the Shuttle Carrier Aircraft, with Tom McMurtry and some other people I can't remember. -- Mary Shafer shafer@skipper.dfrf.nasa.gov ames!skipper.dfrf.nasa.gov!shafer NASA Ames Dryden Flight Research Facility, Edwards, CA Of course I don't speak for NASA "A MiG at your six is better than no MiG at all"--Unknown US fighter pilot
petej@phred.UUCP (Peter Jarvis) (03/26/91)
In article <940@igor.Rational.COM> wab@eclipse.Rational.COM (Bill Baker) writes: > >...... Pilots hate to punch out. >I'm sure that on the first shuttle launch Truly was thinking to >himself, "The hell with the ejection seats........... > John Young and Robert Crippen were the first Shuttle Astronauts......P.J.
rivero@dev8.mdcbbs.com (03/28/91)
In article <953@igor.Rational.COM>, wab@rutabaga.Rational.COM (Bill Baker) writes: > In article <1991Mar23.094700.14237@cimage.com> gregc@dgsi.UUCP (Greg Cronau/10000) writes: >>In article <940@igor.Rational.COM> wab@eclipse.Rational.COM (Bill Baker) writes: >>>I'm sure that on the first shuttle launch Truly was thinking to >>>himself, "The hell with the ejection seats. If the shit hits the fan, >>>I'm shutting down the computers and putting this baby down by the seat >>>of my pants." So instead of thinking of the crew cabin as a >> >>I've got 2 little problems with this: >>1.) If Truly was on the first shuttle mission, he was hiding somewhere in >>the equipment bay. The first mission was Young/Crippen. > > I post two long pieces on the shuttle survival system and almost the only response > is, "It wasn't Truly it was Crippen." Alright, it was Crippen! Jeez.... > >>2.) If you shut down the computers, then you had better eject, because you >>are flying a *rock* at that point! Without the computers, there's no way >>to get the signals from the pilots controls to the control surfaces! >> >>gregc@cimage.com > > Same thing. If it makes the nitpickers happy, substitute the word "overriding" for > the phrase "shutting down." The intent was perfectly clear. For God's sake, I > hope the future of the net isn't typical of this useless pedantery. > > I still say that NASA is shooting itself in the foot with no real crew survival > system. Their rationale, and this applies to a lot of other shuttle Okay guys. The Shuttle is the most wonderful flying machine ever built, but it is NOT, and never was intended to be a commercial transport, no matter what the PR guys said. I knew a member of the Challenger crew. They knew they took a risk when they stepped aboard. YPOU know you take a risk when you fly commercial. Acceptance of that risk is the price you pay for doing what you do. We could save many more lives working on airline safety than criticizing the shuttle.