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Yul
2003-Jan-16, 05:13 PM
Is it correct that the Challenger astronauts were still alive when they hit the water? What is the evidence for this?

SpacedOut
2003-Jan-16, 05:30 PM
On 2003-01-16 12:13, Yul wrote:
Is it correct that the Challenger astronauts were still alive when they hit the water? What is the evidence for this?

As far as I know there is evidence that some of the crew activated their emergency oxygen after the explosion indicating that some survived the initial accident, but due to the extreme violence of that impact there wasn't any hard evidence anyone was alive at that moment.

Eirik
2003-Jan-16, 08:20 PM
I was under the impression, perhaps mistaken, that there were supposidly tapes recorded aboard Challenger that were recovered and had the voices of some of the crew from at least a few moments after the disaster. I wish I could remember more clearly, but I thought a Florida media outlet sued NASA to release those tapes or transcripts and lost.

Am I fuzzy in recollection or just the victem of an urban legend?

Thumper
2003-Jan-16, 08:22 PM
It was my belief that those transcripts were a cruel hoax. But I could be mistaken and will defer to those who know for sure one way or the other.

Rodina
2003-Jan-16, 10:15 PM
There are a bunch of fake transcripts out there which are just about as tasteless as can be.

During the summer of 1986, NASA release transcripts (though not recordings to my knowledge) of about a second or two conversation which took place in the cabin after the more famous "Challenger, go at throttle-up"...which ended with Smith (Pilot) saying "Uhoh." And that's it.

I don't think there was a recording after that and (apparently) cockpit voice recorders were severed from their power sources in the explosion.

See, e.g., http://www.rickadams.org/chall/news.html

http://www.rickadams.org/chall/



<font size=-1>[ This Message was edited by: Rodina on 2003-01-16 17:21 ]</font>

SpacedOut
2003-Jan-16, 10:17 PM
A Link to a report (http://www.hq.nasa.gov/office/pao/History/kerwin.html) by Joseph P. Kerwin, biomedical specialist from the Johnson Space Center in Houston sent to RADM Richard H Truly discussing the fates of the Challenger Crew - May They Rest in Peace.

NASA page for additional information on STS-51L (http://history.nasa.gov/sts51l.html).

Hale_Bopp
2003-Jan-17, 12:51 AM
It is possible that some survived. If I remember correctly, three of the astronauts activated emergecny breathing apparatus.

As to the question of tapes, the New York Times did sue under the Freedom of Information act to obtain whatever tapes existed. NASA, of course, fought the lawsuit and never confirmed or denied if the tapes contained any voices after the explosion. The courts ruled in favor of NASA.

So I guess currently available evidence is inconclusive.

Rob

daver
2003-Jan-17, 01:30 AM
On 2003-01-16 19:51, Hale_Bopp wrote:
It is possible that some survived. If I remember correctly, three of the astronauts activated emergecny breathing apparatus.

As to the question of tapes, the New York Times did sue under the Freedom of Information act to obtain whatever tapes existed. NASA, of course, fought the lawsuit and never confirmed or denied if the tapes contained any voices after the explosion. The courts ruled in favor of NASA.

So I guess currently available evidence is inconclusive.

Rob


You can probably get more definitive answers from the sci.space FAQ. Try here:

http://www.rickadams.org/chall/

and here

http://www.geocities.com/CapeCanaveral/4411/faq-b.htm#challenger

I'll summarize. Three air packs were turned on. This seems likely to have been done after the breakup. The forces sustained by the crew during and after breakup (until water impact) were surviveable. I'd guess that the cabin started to depressurize after the breakup--that's most likely why the air packs were turned on. I don't know their training, though, maybe they'd be turned on in any emergency. Regardless, the investigators were not able to determine whether the cabin was still airtight before impact with the water. The oxygen lines would have been cut during the breakup; if the cabin did not maintain pressure the air packs would not have been sufficient to keep the crew conscious for any length of time.

Thumper
2003-Jan-17, 12:51 PM
On 2003-01-16 17:17, SpacedOut wrote:
A Link to a report (http://www.hq.nasa.gov/office/pao/History/kerwin.html) by Joseph P. Kerwin, biomedical specialist from the Johnson Space Center in Houston sent to RADM Richard H Truly discussing the fates of the Challenger Crew - May They Rest in Peace.

NASA page for additional information on STS-51L (http://history.nasa.gov/sts51l.html).


Thanks for the link. Very sobering, and brought tears to my eyes again some 17 years later. People talk about remembering exactly where they were when they heard that John F. Kennedy was shot. I was not alive then. I remember exactly where I was and what I was doing when a co-worker came out to tell us that the Challenger had exploded during launch.

Colt
2003-Jan-17, 07:07 PM
This brings up something that has always bothered me about the shuttle.. Why doesn't it have some sort of ejectable section? Right now the emergency protocol for the shuttle at launch is for it to jettison the tank, SRBs, and do a roll and come back in to land. In other words, you take the entire shuttle or not. -Colt

daver
2003-Jan-17, 07:28 PM
On 2003-01-17 14:07, Colt wrote:
This brings up something that has always bothered me about the shuttle.. Why doesn't it have some sort of ejectable section? Right now the emergency protocol for the shuttle at launch is for it to jettison the tank, SRBs, and do a roll and come back in to land. In other words, you take the entire shuttle or not. -Colt



Well, you do the calculations and take your chances. Figure what problems are most likely to occur, figure different ways of dealing with them and how much weight they add, grit your teeth and fly with the results. Perfect safety is an illusion, and all that.

Making the crew cabin ejectable would increase the weight significantly (additional stiffening in the cabin and in the frame, pyrotechnics to blast the cabin out, recovery system for the cabin, etc.) It would complicate the plumbing. It would add yet another failure mode (what if the pyrotechnics go off at the wrong time). I believe the idea was considered and discarded. The fact that the only disaster in the program to date may have been helped by an ejectable cabin (or may not--the frame of the cabin may have been twisted too severely for an eject to occur) probably made some people shake their heads and go over the numbers again, but they'd likely come to the same conclusion.

I haven't been following spacecraft design too closely. The ESA for a while had a winged reusable craft designed for an expendable launch. At one time they were considering having some sort of recovery device (ejection seats, ejectable cabin)--this was eventually removed due to cost, weight, and safety issues. Eventually, of course, the whole project was cancelled. The point, such as it is, is that even in the face of Challenger, such recovery mechanisms were discarded.

The fact that the current abort mode should a problem occur during boost phase involves riding it out until the SRBs burn out bothers lots of people, particularly those that wanted liquid fueled boosters in their place. Probably too late now to do anything about it.

Kelfazin
2003-Jan-19, 05:26 AM
I was in 4th grade music class at the time of the accident. We were having a "reward" day and were listening to the radio when they interrupted with the news.

As far as Challenger conspiracy theories/hoaxes go, many years ago I heard the gov't had planned on putting over 30lbs of plutonium on the shuttle but pulled it off at the last second because a civilian was on board, thereby averting a disaster which would have wiped out the entire eastern seaboard (their damage estimate, not mine)

Hale_Bopp
2003-Jan-20, 02:04 PM
30 lbs of Plutoniom! Egad! Where did that come from?

The only time I am aware they would send nuclear material into space is if it were the power source of a satellite. NASA spends most of its time trying to REDUCE the weight of the shuttle so I find it hard to believe they would just randomly throw an extra 30 lbs of cargo in there.

After all, we know the effects of space travel on plutonium...it becomes weightless...and that's about it /phpBB/images/smiles/icon_smile.gif

Rob

Kaptain K
2003-Jan-20, 03:20 PM
HUH! If I remember correctly, 30Kg is somewhat in excess of the critical mass for Pu239. Put it all in one box ... BOOM!

kucharek
2003-Jan-20, 03:46 PM
Maybe someone mixed up things. IIRC, the flight planned after 51L was to be to launch Galileo, which had a plutonium-238 dioxide driven RTG energy source.

Harald

cable
2003-Jan-20, 03:56 PM
btw, what would have happened if when departing from moon, asc. LM engine did not ignite ??
was there any rescue mission ??

in the russian program, it seems there was an unmanned LM to be kept on moon, as spare in case of failure of the manned misssion.

calliarcale
2003-Jan-20, 04:44 PM
It may have been a 30 lb RTG (Radioisotope Thermoelectric Generator), which would have contained plutonium. Possible, but not all that likely; it would have been the power source for a spacecraft, and they were already carrying a large payload (a TDRS satellite). Then again, maybe the TDRS was a replacement -- several later missions did carry plutonium-powered RTGs, most notably STS-34 in 1989, which carried Galileo into orbit. (Galileo is currently on its last orbit of Jupiter before it plunges into the giant planet in a suicide dive to prevent it accidentally contaminating Europa with stowaway terrestrial bacteria.)

But it would not have been a major problem -- RTGs are designed specifically to tolerate catastrophic launch vehicle failures without loss of structural integrity. If there had been an RTG on board, it would have survived the accident with no difficulty and been easily retrieved from the ocean floor afterwards. (RTGs *have* actually been subjected to these kinds of things, deliberately and accidentally, and several have even survived reentry and been collected and recycled!)

At least three Challenger crewmembers were able to activate their emergency oxygen packs. One of these was the commander. At least one was not able to. The other three emergency packs were not recoverable or at least were recovered in such poor condition it could not be determined whether or not they were activated. It is not known to whom the other packs belonged; they were only able to identify one as belonging to the commander (his name was Frank Scobee). This is about the most information I'm aware of which NASA has released to the public about the condition of the crew compartment on recovery -- given that they were unable to identify which packs went with which crewmembers, it is certain that the damage was considerable, though most of it was probably from the high speed impact with the water.

The oxygen packs would have had to be activated within seconds of the accident; the cabin would certainly have depressurized, given the way in which it was torn free of the midfuselage, and at that altitude they would have had only a few seconds before losing consciousness. (This is why airliner crews instruct you to put your oxygen mask on before assisting small children -- otherwise you will pass out and the child will likely not be able to help you.) Even with the oxygen, they were not wearing pressure suits; they could still easily have lost consciousness even if the emergency oxygen was able to keep them alive.

I read an estimate once that said the impact was probably about 200 Gs. It is not possible to survive that; you will be killed instantly by such a force. The crew probably were not killed by the explosion; they may have quickly lost consciousness, however. They crash certainly did kill them, however.

There are no tapes of voices after the impact; the Shuttles do not carry a cockpit voice recorder black box like airliners do (and not even all airliners carry these). In recent years, they have begun videotaping the ascent from the flight deck, but this footage is stored on a tape inside the camcorder and is not replayed until after the payload bay doors are opened. Such a tape would have a ludicrously slim chance of surviving the impact, especially given how much damage was sustained by more rugged equipment. There is a voice recording going up to T+1:13 seconds; this recording is made from the air-to-ground transmission relaying not exactly cockpit sounds but rather everything that is said into the crew's voice mikes. At the time, this was only the flight deck crew -- nowdays everybody is wired up to this system. The transmission terminated milliseconds after the explosion, when the orbiter would have lost electrical power either because of the fuel cell tanks rupturing or, more likely, because of the way the crew compartment was actually ripped away from the midbody, trailing umbillical cables and piping. There is no recording after that point, but a very sick fake transcript was written by an anonymous party and circulated. If I recall correctly, that transcript conflicts directly with the real one which terminated at T+1:13, which easily demonstrates that it is fabricated.

After STS-51L, many people asked why there were not ejection seats for all crew, or why the cabin was not made to eject. There are several reasons for this. First, Columbia did carry modified SR-71 ejection seats for the commander and pilot; to this end, she was given a hatch in the roof that would eject explosively before the seats were ejected. It was not possible to include more than two ejection seats for several reasons, particularily weight limits and the sheer complexity of trying to time separate ejections (you can't eject all of the seats at the same time or you'll just kill all of the astronauts by ramming them into one another), so when Columbia started carrying larger crews, the seats were deactivated -- it was considered immensely crass to provide ejection capabilities for only part of the crew. If some must die, it would be unthinkable to save the commander and pilot -- it's sort of the same mentality that says the captain of a ship must evacuate last. Eventually, the seats were deleted to raise Columbia's payload capacity (the ejection seats are very heavy) and in the last refit they deleted the rails as well and some of the hardware for popping out the roof panel. They couldn't delete it all, so Columbia remains heavier than her sisters, which gives her a lower payload capacity.

So that's why there are no ejection seats. Why doesn't the crew cabin eject? The reason is one of practicality. The neccesary equipment would add a great deal of weight and complexity to the vehicle. Having a part of the airframe which can actually sever itself adds a lot of safety concerns because you must prove it will not break away except when ordered to do so. This adds a great deal to the cost, so that is why the Shuttles were not originally designed that way. As to why they were not rebuilt after STS-51L to have ejectable crew cabins, the answer is mostly that it would not be practical to alter the Shuttles that much; it may not even be possible, since they rely on several beams that firmly grip the crew compartment in a sort of cage. You'd have to cut those to either provide an ejection path or to make them able to break themselves away. Neither is simple and both would dramatically change the way loads are distributed around the airframe during ascent and reentry, both highly critical phases.

There was a brief plan back in the 70s to outfit Shuttles with a "lifeboat" -- a refit Apollo CM which would allow the crew to abandon an orbiting Shuttle. This was abandoned because it reduced the Shuttle's payload capacity far enough that there was no longer much point flying the Shuttle anyway.

ToSeek
2003-Jan-20, 05:31 PM
On 2003-01-20 10:56, cable wrote:
btw, what would have happened if when departing from moon, asc. LM engine did not ignite ??
was there any rescue mission ??


There were no provisions for a rescue mission. I would think the logistics (at least 3 crewmembers in the rescuing lunar module, at least 4 in the rescuing command module, orbital dynamics, etc.) would have made it impossible with the current hardware.

Avatar28
2003-Jan-20, 09:31 PM
So that brings up another interesting point. Since it takes so long to plan and launch a shuttle mission, what would be the procedure if one suffered catastrophic failure in orbit.

Obviously they would, ideally, try to dock with the ISS. But let's suppose that wasn't possible, what would the process be then?

David Hall
2003-Jan-20, 10:06 PM
One more thing about ejection seats. Even if the shuttles had them, they'd only be able to deploy them within a very short window of time during lift-off. They couldn't eject too low, nor once they got above a certain altitude. so their entire useful span is, what, a couple of minutes maybe?

Maybe it would be possible to use them during the glide phase of reentry as well, but then again that's a less critical step anyway. There's little chance of explosive mishaps, and if they lost control for some reason they'd still have a few minutes to right themselves again before crashing.

daver
2003-Jan-21, 01:54 AM
Some quibbles



At least three Challenger crewmembers were able to activate their emergency oxygen packs. ...

The oxygen packs would have had to be activated within seconds of the accident; the cabin would certainly have depressurized, given the way in which it was torn free of the midfuselage, and at that altitude they would have had only a few seconds before losing consciousness. (This is why airliner crews instruct you to put your oxygen mask on before assisting small children -- otherwise you will pass out and the child will likely not be able to help you.) Even with the oxygen, they were not wearing pressure suits; they could still easily have lost consciousness even if the emergency oxygen was able to keep them alive.



These were emergency AIR packs, not oxygen packs--the difference is important. The air packs would have been insufficient to provide enough oxygen to keep the crew conscious for any appreciable interval. That's one of the things that changed post-Challenger. Another is the exit pole.




The crew probably were not killed by the explosion; they may have quickly lost consciousness, however. They crash certainly did kill them, however.



If the cabin had a largish hole ripped in it, they would have quickly lost consciousness. However, the investigating teams were unable to say whether this size hole was ripped or not.

joema
2003-Jan-21, 11:35 AM
Kelfazin said: "...30lbs of plutonium on the shuttle...would have wiped out the entire eastern seaboard "

The Apollo 13 LM ascent stage had a Pu 239 Radioisotope Thermoelectric Generator. Due to the abort, it reentered earth's atmosphere rather than landing on the moon. No known ill effects from this. It certainly didn't wipe out a seaboard.

cable said: "btw, what would have happened if when departing from moon, asc. LM engine did not ignite ?? was there any rescue mission ??"

No rescue possible. However this was understood when the LM ascent engine was designed, hence it was the simplest and most reliable in the entire Apollo program. It was non-throttlable, used no pumps, no regenerative cooling, all valves and feed lines were redundant. It used hypergolic fuels, so required no ignitor. Tom Kelly, head of the Grumman LM project said the oil furnace in peoples homes was more complicated than the LM ascent engine.

Re Shuttle jettisonable cockpit, certain FB-111 and early B-1 bombers had such a mechanism. They were very heavy and complex, and weren't that effective. The few times they were used, usually one or more crew died. I think all the remaining B-1s use ejection seats.

There's a diagram here: http://showcase.netins.net/web/herker/ejection/eject_paper.html

Nonetheless NASA has seriously considered a capsule-type ejection system for the Shuttle. It would be quite expensive (cost and weight) and inject it's own additional risk. I doubt they'll proceed with it.

One interesting anecdote: Gemini had ejection seats. Gemini 6 had an on-pad engine shutdown, possibly after it lifted off a fraction of an inch. The rules called for an ejection. However Wally Shirra was very concerned over ejection seat reliability (he'd seen dummies decapitated when testing Gemini ejection seats). He stayed put, they safed the booster, and it saved the mission (Gemini 7 was already in orbit awaiting rendezvous).

Launch escape systems are nice insurance, but they have risks and costs.

David Hall
2003-Jan-21, 01:46 PM
Thirty pounds of anything scattered in the upper atmosphere isn't going to do much. It'll just get carried away by the jet stream and dispersed over too large an area to do any damage. Location is important too. Especially, launches from Florida go out east over the Atlantic. Not much to harm out there; the ocean could swallow 30 pounds of stuff without even a hiccup. An explosion on the launch pad would be the worst catastrophe, but even then it wouldn't cover a huge area. It would be a localized disaster that could be cleaned up [i]relatively[i] easily.

Tim Thompson
2003-Jan-22, 02:24 AM
ejection seats in the shuttle would be essentially useless. The liftoff acceleration of a shuttle is about 7.23 m/sec, about 0.74 g, which I calculated from the total thrust of the solid rocket boosters and shutle main engines (34,000,000 Newtons, 7,725,000 pounds), applied against the weight of the entire stack of launch mass (19,570,000 Newtons, 4,400,000 pounds, or 1,995,574 kg, which I already know has more significant figures than justified, so don't jump all over me about it). At that acceleration, the shuttle will hit Mach-1 in about 45 seconds or less. Once it's supersonic, ejection, either of seats or cabins, hardly seems an option.

I can't find out what the velocity or acceleration profiles for a shuttle launch are, but I would bet that the acceleration goes up before it goes down (protocol requires that the acceleration never exceed 3 gs, or about 29.42 m/sec). So they may well be supersonic before 45 seconds have passed, if the real acceleration goes up from a low launch value.

Also remember that the shuttle does its roll maneuver as soon as it clears the launch tower (starts about 3 seconds after launch). Within 20 seconds after launch, it is upside down, so any ejection has to be at a high enough altitude for that not to matter much. It's pitch angle by then is about 78 degrees, but I'm not sure how fast it is gaining vertical altitude. You certainly don't want astronauts ejecting themselves into the ground.

So, as I see it, the window for "safe" ejection, if there is one at all, can't be more than 30 seconds long, between speed & altitude considerations. And, of course, ejection mechanisms would have meant nothing during the Challenger episode, where everything happened far too fast for any ejection mechanism to do anything except kill the astronauts as effectively as the disaster did (they can't eject seats from a tumbling cabin traveling at a few Machs, and the cabin was "ejected" anyway, by the accident).

<ul>
Space Shuttle Reference Manual (http://spaceflight.nasa.gov/shuttle/reference/shutref/)
Space Shuttle Lecture Notes (http://www.personal.psu.edu/faculty/r/8/r81/055/space_shuttle/shuttle.html)
[/list]

joema
2003-Jan-22, 05:26 AM
I'm not sure it's correct to say ejection seats in the Shuttle would be useless. After all the first four shuttle flights *did* use modified SR-71 ejection seats. They were considered good to 100,000 feet and high supersonic speeds, just like on the SR-71. Numerous successful SR-71 ejections have happened at very high altitudes and speed. Gemini also used ejection seats.

It's true there was some concern over how safe the seats were and the useful envelope. Before STS-1 someone asked John Young about how the seats would work under extreme conditions, and he replied, grinning: "you just pull the little handle".

Supersonic ejection seats typically have mechanisms to restrain and protect the pilot's limbs from air blast. Some previous high-perf vehicles (XB-70, B-58) had fully encapsulated ejection seats to protect the pilot from a double or triple sonic ejection. Here's a cool picture of one: http://users.bestweb.net/~kcoyne/b58capsule.htm

It's technically possible to provide this for the shuttle flight deck. Doing it for the mid deck crew would be very difficult and expensive.

Re whether an ejection seat would be useful for a Challenger-style disaster, it's possible it would. It's generally believed the astronauts were conscious and alive after the explosion, at least for a few seconds. Had they been in pressurized flight suites there'd have been plenty of time to pull an ejection handle. Ejection seats are fully self-contained regarding power, pyrotechnics, etc. It might seem impossible that an ejection seat could work under a tumbling, high-g situation, yet numerous successful ejections from tumbling, broken fighters have happened. Here's one page showing an ejection from a broken, flaming Mig-29: http://www.parlier.com/web_p06.htm

I'm not saying they should put ejection seats in the shuttle at this late date, but except for the mid-deck problem, there's no overwhelming technical obstacle to this.

However given the post-Challenger improved abort options, you could make a good case ejection seats aren't worth the additional cost, weight, and risk.

There are now survivable abort options even for multiple SSME failures, as long as the SRBs work. The SRBs positively must work, but (Challenger notwithstanding) they're fairly simple devices -- no complex turbomachinery. They can be X-rayed and scrutinized very closely.

But personally if I were an astronaut, I'd rather have an ejection seat option.

-- Joe