The Challenger Explosion

[Raven]

My question is in regards to the question of what happened on the Challenger after the explosion. http://www.straightdope.com/columns/950331.html

Why didn't the shuttle have a parachute like some of the newer shuttles do or the Lunar Modles from the Apollo missions? I am really curious about this. Please help me.

[Yarster]

My memory of the shuttle exlosion was that it didn't exactly come down in one piece, but even if it did, the parachute system you speak of would be incredibly expensive relative to the number of accidents that occur (up until that shuttle flight the casualty rate was...zero)

Such a system could not be a simple "stick it on the outside" type unit or it would burn up in re-entry. So now you are talking about a fancy hydraulic/ electrical system that must be deployed like the landing gear, but otherwise protected in re-entry.

Now keep in mind that when the shuttle explosion occurs, I doubt all the hydraulics/ electrical system were otherwise functioning normally. For that matter, the pilots may have been knocked unconscious by the blast and thus might not deploy such a chute even if they could.

And even if the shuttle did survive quasi-intact and all these systems worked, I don't know of many parachutes that work well when on fire :)

[kunilou]

The Shuttle, in case you haven't actually seen it in person, is huge, so the idea of parachutes was thought to be impractical. If it was necessary to abort after launch, the plan was to separate it from the booster and glide to a landing. The prospect of the booster blowing up was considered to be an unmanageable risk.

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I understand all the words, they just don't make sense together like that.

Even if the shuttle did have a parachute, it would not have mattered since the shuttle was blown to pieces in midair.

[DSYoungEsq]

Sorry to burst your bubble, microshroom, but the shuttle did NOT burst into pieces in mid-air. As explained by Uncle Cecil, the main cabin survived relatively intact all the way to the splashdown in the ocean. You can read the gory details at: Did the astronauts survive the Challenger explosion long enough to realize their plight? (http://www.straightdope.com/classics/a4_024b.html)

[InutilisVisEst]

Actually, I read the Congressional report and they've got some fine photos. Challenger's crew cabin, which "floats" inside the fuselage, was apparently intact following the explosion (which was not an explosion so much as a fireball).

The B-1 bomber was originally designed with an escape capsule similar in size and shape to the Shuttle. After the requisite explosive bolt detonations, the capsule would be propelled away from the fuselage quite a distance before deploying parachutes. Inflatable bags on the underside would help cushion the final shock of landing.

Now, at at US$10000 per lb. to get something into orbit, it would still be expensive, but I think it would be practical. I'll try to find more info on the capsule, including pix, to substantiate the size/shape similarity claim.

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I lead a boring life of relative unimportance. Really.

[scr4]

The B-1 bomber was originally designed with an escape capsule similar in size and shape to the Shuttle.

By this you mean that the whole crew compartment of the B-1, which is similar in size to the crew compartment of the Shuttle, acts as an escape capsule? Interesting. The Shuttle carries up to 7 people though, how large is the crew of the B1?

Anyway, the parachutes on the later Shuttles are for slowing down the Shuttle after touchdown. I don't think any major safety device was installed after the Challenger incident.

The Apollo and earlier manned rockets, as well as Russian and (now) Chinese rockets, have small rockets which yanks the crew capsule away from the booster in the event of an accident. One cosmonaut was saved when the booster blew up on the pad. If something went wrong with the Shuttle on the pad, the crew has to squeeze out of the hatch.

Anyone know if the Shuttle is the only manned rocket which has the "if an engine quits now we're dead" period?

[Ringo]

The original B-1 prototype (I don't know if this was incorporated into the production series) had an escape mechanism which blew the cockpit, with all three crew members, out together. One of the prototypes crashed in testing and they lost one guy using this system.

[Johnny L.A.]

The B-1 bomber was originally designed with an escape capsule similar in size and shape to the Shuttle. After the requisite explosive bolt detonations, the capsule would be propelled away from the fuselage quite a distance before deploying parachutes. Inflatable bags on the underside would help cushion the final shock of landing.
As it happens, I was on the B-1 data team when tail #159 went down. The capsule did indeed seperate and come down by parachute. As I recall, one of the landing bags failed to deploy or deployed improperly, resulting in the death of Rockwell test pilot Doug Benefield. The co-pilot (whose name escapes me, but it was Polish) was seriously injured in the crash but recovered. The escape module was dropped in favour of an ejection seat for each crew member.

I did a very brief search using "space shuttle" and "ejection seats", but didn't see anything in the titles that looked worth investigating. (I did see one site that mentioned astronauts Young and Crippen "sat on ejection seats" in Columbia.) Given that accidentally activating an ejection seat while in orbit is undesireable, I don't think it's a good idea to put them on a shuttle.

Doesn't the shuttle have an escape tunnel?



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"I must leave this planet, if only for an hour." -- Antoine de St. Exupéry

Are you a turtle?

[kinoons]

On a similar theme, the F111's crew capsule detached, and the capsule returned to earth as one unit. However it is only maybe 40 feet long, and 10 feet wide. It was only designed to hold two crew members. Goes to show that the method of recovery of a crew capsule is good enough for the Air Force

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...for more silky smooth segues, write to "silky smooth segues" 610 n 10th street, Albuquerque NM 87109.

[Sofa King]

I would cite the successful test of the X-38 Crew Return Vehicle (http://www.space.com/missionlaunches/launches/x38_parafoil_000414.html) as evidence that the Orbiter is a bastardized, Congressionally crippled space vehicle which stands as a testament to the versatility of mankind--on a budget.

The X-38 relies, whether acknowledged or not, on the research done by the Lifting Body project of the late 60's-early70's. You know, the one Steve Austin crashed at the beginning of every Six Million Dollar Man episode. The Lifting Body project was in turn a foster child of the Air Force's Dyna-Soar project. It also incorporates parafoil technology that was originally considered for the Gemini and Apollo missions for land-based vehicle returns.

William Proxmire, God rest his soul in a giant vat of rancid butter, was active in repeatedly holding his "Golden Fleece" award over NASA's head while the development of the Orbiter was completed. Among the innovative devices that were intitially to be included in the design of the Orbiter were ejection seats and emergency fly-around rockets for the Orbiter. Both were canned because of prohibitive costs. Later re-designs made the crew compartment of the Orbiter detatchable so that a parasail apparatus could be deployed in the event of catastrophic failure. That, too was rejected for monetary considerations.

However, that particular redesign was the one that was eventually approved. When the Challenger disintegrated, the capsule section, sans the terribly expensive parafoil crew return system, tumbled into the ocean, and inconclusive evidence points to the possibility that at least one of the creew members was able to open an emergency locker during the nine-mile descent.

The Orbiter still does not have the ability to circle around the runway should it miss its one opportunity to hit good ground in Florida. Cost considerations and the decrepitude of the two modified 747's built to transport the Orbiter impel NASA to strongly encourage their pilots to land at The Cape, rather than Edwards, White Sands, or other possibly safer spots, in spite of astronauts' protests. If and when an Orbiter makes a great swath through the swampy grounds of Canaveral, I hope someone holds a wedge of Wisconsin Cheddar to the sky and says, "this, William, is what you have wrought."

[InutilisVisEst]

I can't find anything on the Web with dimensions or pix of the B-1 capsule, although the F-111 capsule (http://www.f-111.net/ejection.htm) seems rather popular. B-1 has a crew of 4, which makes the capsule similar in length and width. The Orbiter's two levels make the crew compartment taller, but weight is really the major issue: the orbiter crew compartment has lots of stuff in it. As mentioned, the B-1 capsule was dependent on landing bags to cushion an otherwise fatally hard parachute descent, so a similar system for the heavier Orbiter might be difficult. In fact, a decision not to upgrade the F-111 was once made because it would make the escape capsule too heavy.

I vaguely remember the parasail Sofa King mentioned, but had no idea the floating Shuttle crew compartment was part of an escape system originally. Excellent info there!

Despite the loss of life in the B-1 capsule landing, the reason given for the switch to ejection seats was the logistical nightmare of checking all the connections and severance points between the airframe and the capsule. With the switch from supersonic B-1A to subsonic B-1B, the need for an encapsulated escape system (first used for the B-58, I think) evaporated.

Yes, Columbia (and Enterprise, IIRC) had ejection seats while being flown by two-man crews during testing. The whole fleet now has an egress system (http://www.ksc.nasa.gov/shuttle/technology/sts-newsref/sts_egress.html) (for use during controlled level flight only!) that basically consists of jumping out.

Here's a neat bit:
The probability of the flight crew surviving a ditching is very slim.
High-speed, high-alpha deadstick landings on water or unprepared terrain are not conducive to health and long life, so we suggest you take a flying leap.

[Silo]

And it all happened because of sucky o-rings.

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Two wrongs do not make a right...but three lefts do.

[Icerigger]

The XB-70 had escape capsules for the two
man crew as well.

Well, I meant to say the gas tank exploded. My keyboard is messed up. What are you gonna do? :)

[WillGolfForFood]

Originally posted by Silo:
And it all happened because of sucky o-rings.

... which the engineers at the company that built the module containing those O-rings figured out probably wouldn't survive a low-temperature liftoff (it was 28 degrees when the liftoff occured) - but they couldn't convince NASA or their upper management to call off the launch.

A few years ago I went to a seminar on making management presentations. The rest of the seminar was godawfully boring, but they had a fascinating section detailing those engineers' frantic attempts to alert NASA and their management to this problem.

The engineers had discovered that previous shuttle launches that occured below 50 degrees all had O-ring damage, with the damage more significant as the temperature dropped. And, as all materials engineers know (the seminar leaders told us), material flexibility drops off with the square of temperature drop, not just linearly. The shuttle didn't have a chance at 28 degrees.

The engineers were given an opportunity to make a last-minute presentation of their data describing the problem to NASA and their upper management. The seminar leaders showed us the almost-completely-unintelligible charts and graphs that the engineers presented. Given the incredible political pressure NASA was under to launch the first teacher into space, those charts didn't stand a chance - and NASA ordered the launch.

The seminar leaders then put up alongside those original charts some simple charts that detailed the problem in such a clear manner that NASA almost certainly would have called off the launch.

So (the seminar leaders told us), the shuttle disaster was really caused by poor presentation skills.

[Chronos]

"Poor presentation skills", my o-ring! Were I the head honcho at NASA, and my engineers told me, "If you launch now, it'll blow up", I would either cancel/postpone the launch just on their say so, or at leasttake the time to make sure that I understood their arguments. Of course they weren't as clear as they could have been, they were kinda rushed, and had the stress of knowing that seven lives and umpteen dollars depended on them. I don't blame the engineers, I blame the management.

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"There are only two things that are infinite: The Universe, and human stupidity-- and I'm not sure about the Universe"
--A. Einstein

[Koxinga]

Originally posted by InutilisVisEst:
High-speed, high-alpha deadstick landings on water or unprepared terrain are not conducive to health and long life, so we suggest you take a flying leap.

Regarding water ditching: would only the impact be the fatal factor? Since the shuttle is presumably watertight, couldn't the crew survive long enough for rescue if the Shuttle sank in relatively shallow water?

DHR

[InutilisVisEst]

From a recent ep. of Futurama, as the ship sinks in the ocean:

Crew member: "How many atmospheres can the ship take?"

Prof. Farnsworth: "Since it's a space ship, I'd say between zero and one."

Actually, the windows, hatches, etc. need to keep the wind out during liftoff just as much as they need to keep air in while in space. So, an intact cabin should be able to keep the crew going for a while.

NASA just doesn't seem to think ditching on water is survivable at all, since the shuttle's as much lifting body as it is plane. As soon as the tail hit, the nose would slam down onto the water. Pretty nasty with that high stall speed.

[Hail Ants]

I can't site any references, but from what I remember:

In the first four flights the shuttles were equipped with ejection seats (two of them for a two-man crew). The pilot and copilot both wore full pressure suits during takeoff and landing, just like Mercury & Apollo (a high altitude ejection would require it).

After flight number four the shuttle's status was changed from "test" to "operational". The ejection seats were removed and the crew cabin was now deemed a "shirt-sleeve" environment. Regardless, a shuttle could never have had more than two ejection seats, and to carry its full payload (i.e. be "operational") it couldn't have any.

After Challenger, the crew went back to wearing full pressure suits at TO & L (a practice which should never have been stopped to begin with).

Although its debatable, since the G forces of the explosion & breakup were not enough to even cause unconciousness let alone death, and since the crew cabin remained relatively intact, if they could have unbelted and bailed out of the falling crew cabin (they would have been weightless once reaching terminal velocity) a supply of oxygen and a parachute would have saved them.

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I for one welcome our new insect overlords... - K. Brockman

[Sam Stone]

Except that they wouldn't have been weightless if the non-aerodynamic cabin was A) at terminal velocity or B) tumbling. The forces that can build when a vehicle tumbled can be tremendous. There was an accident at the Reno Air Races last year where an unlimited race plan lost a wing during the race and crashed. Post-crash analysis showed that the pilot was probably killed instantly by the resulting force on the fuselage when it changed attitude very quickly, even though it hit the ground in one piece.

Also, if the cabin maintained some level of pressurization, it would have been impossible to get the door open. Even a difference of one PSI between the outside and inside of the cabin would make it impossible to budge the door. And even if there was no pressure differential (or if the door was equipped with explosive bolts and opened outwards), a slight deformation of the cabin might have lodged it firmly shut.

[hflathead]

quote
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On a similar theme, the F111's crew capsule detached, and the capsule returned to
earth as one unit. However it is only maybe 40 feet long, and 10 feet wide.
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not trying to get to exact, but I worked the F-111 mod project for a few years, and the capsule is much smaller than that, maybe 7'-8' x 10'-12'. One of the complaints from the flight crew was back injury/disc compression on landing. later, Tom

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Uhm...Ya kan't git there from heyre!

[Ra]

Originally posted by InutilisVisEst
Challenger's crew cabin, which "floats" inside the fuselage, was apparently intact following the explosion (which was not an explosion so much as a fireball).

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You are correct. It was more of a fireball. This "fireball" was caused by the LOX and LHY leaking from the ET after the "explosion" (I use that term loosely here). And if you look closely, the SRBs fly off toward the ocean RELATIVELY undamaged. It was the burning fuel from the ET that "Blew Apart" the orbiter.
Something else that may come in handy for those of you who may not know, the entire assembly (SRBs, ET, Orbiter, and SSMEs) is known as the shuttle. Note: The SSMEs (Space Shuttle Main Engines), though attached to the orbiter, is considered a completely different component.

-Ra

[Ra]

The "Green Vial" Stuff you've heard about was not a top secret material. It's a rescue beacon. If you see pictures or video of the Mercury, Gemini, or Apollo splashdowns, you'll notice a green smoke around them. This was used in case they splashed down farther downrange than expected. This would be a sort of flare to overhead aircraft saying "Here we are come and get us out of this old rickity capsule"

I have looked through all the blueprints for the orbiter I own and have found no evidence of a beacon substance yet prior or following the Challenger incident. It wouldn't be uncommon for them to use it though.

Something else useful, We've never lost a man in space. All our deaths were during a launch or during a launch test.

-Ra

[Bear_Nenno]

I saw the shuttle blow up in person!! I was definitely a huge fireball!!






:(

[Duck Duck Goose]

You were a fireball? Golly, didn't it hurt?

[Dystopos]

Regarding the attempts to caution NASA about launching in cold weather, the engineers used very limited data to make their point and ended up agreeing that the evidence to back up their caution was inconclusive. There is a very elegant analysis of the presentations in Edward Tufte's Visual Explanations (http://www.amazon.com/exec/obidos/ASIN/0961392126) including reproductions of the actual tables generated to show the danger: tables which, because of poor design and informational clutter, could lead to no certain correlation between O-ring failure and cold temperature. He quotes an aeticle by Richard Lighthall ("Launching the Space Shuttle Challanger: Disciplinary Deficiencies in the Analysis of Engineering Data" IEEE Transactions on Engineering Management 38, Feb. 1991) as concluding that: Of the 13 charts circulated by [Morton] Thiokol managers and engineers to the scattered teleconferences, six contained no tabled data about either O-ring temperature, O-ring blow-by, or O-ring damage {these were the primary outlines of arguments being made by the Thiokol engineers). Of the seven remaining charts...six...included dato on either launch temperatures or O-ring anomaly but not both in relation to each other."

In the face of (justifiable) skepticism of their concerns Morton Thiokol official Joe Kilminster made the following (unjustified) recommendation to NASA the night before the launch: "MTI recommends STS-51L launch proceed on 28 January 1986"

Since there WAS concern about temperature affecting the O-ring's elasticity and since no previous shuttle had launched at less than 53 degrees F, it would, of course, have been prudent to delay the launch and shift the burden of evidence to demonstrate that no danger was present (rather than merely that no danger could be verified with thin evidence).

In the face of administrative, financial. public relations and political this caution was not deemed to have sufficient merit. In the real world those sorts of decisions must be made and this decision had a tragic aftermath that was, in simple terms, the consequence of trying something that had never been tried before (a cold-weather launch)

[Sith Sheriff Brody]

The shuttle has one parachute, known as a drag chute, that is used to slow it down after landing.

As for astronaut escape, they must exit the cockpit and run across the gantry to a few 'baskets' hanging on wires leading to a bunker a few hundred yards from the launch platform.


-SSB

[Fear Itself]

Uh, just a small nit to pick there, Sheriff. Its not a drag chute, its a drogue chute. (http://spaceflight.nasa.gov/shuttle/reference/shutref/srb/recovery.html). Carry on.

[Sith Sheriff Brody]

Okay, I sit and type corrected.

Also, for those interested in Buran (You'd know what I'm talking about), see my thread in the IMHO area....probably the wrong forum...but it's too late now...


-SSB

[Revedge]

My father worked on the preliminary design phase of the shuttle. (His branch at NASA was Advanced Mission and Design.) The problem with shuttle escape systems was that there was an extreme amount of meddleing in the design phase. It was more than just cost involved. The Department of Defense was insistant on the shuttle being able to perform certain missions. It had to be able to lift a certain size satellite to a specific height orbit. With ejection seats for everyone, the added weight wouldn't allow the shuttle to perform the tasks required by DOD. (The solid fuel boosters were added because of the extra requirents of the DOD. For NASA's purpose, the shuttle didn't need to be as big or fly as high.) DOD had big plans for the shuttle fleet. Remember the multi-billion dollar launch complex at Vandenberg in California? It was mothballed after the disaster. It was one of the reasons for the changes in design. DOD wanted to be able to launch from Vandenberg on a north/ south polar orbit. (The better for spy satellites.) Problem is that you lose the added boost of the rotation of the earth.

It was also decided that the safety gain would be minimal. Escape systems would be usefull for only a few seconds of launch time for missions that would last for days. Remember that the shuttle had already passed through "max-Q" which is the period of maximum dynamic pressure of the air on the spacecraft. If someone had tried to eject at that time they were moving so fast in relation to the air, it would have killed them.

Ironically, it was expected that they would lose one shuttle during the life of the program. However they expected it to happen on re-entry.

[Johnny L.A.]

I don't think there are green "smoke beacons" on the shuttle. It is likely, however, that it has sea dye markers. This is what you see floating in the water around capsules, and around Tom Cruise in Top Gun.

After an emergency (and this applies to lost campers as well as astronauts) you want to "make yourself big". The best way to do this is with a radio, as it boradcasts in a wide area over all directions. A signal mirror also makes you "bigger". Its flash can be seen for miles, but it is unidirectional. Military aviators also carry a combination smoke/flare. I don't know what colour the smoke is, but I think it's white. The downed aviator uses the smoke in the daytime or the flare at night. They also carry an arial "pencil" flare that they can launch that burns for a few seconds. A strobe is also in the survival vest, which can bee seen at a good distance at night. As you can see, all of these devices make the pilot "bigger", but as you go down the list the effect is smaller.

The last thing an aviator in the water can use is the sea dye marker. This creates a "puddle" of green that (one hopes) will be seen by a rescue aircraft. Naval aviators also have reflective tape on their helmets, which also have a velcro patch to which they can attach the strobe.

There is a new product that is being issued to some aircrews that is a long, bouyant orange ribbon. It's said to be more effective than a sea dye marker.

As much as NASA wishes to give the impression that space flight is "safe", it is really only "relatively safe". This relative safety has come at a high price. Who knows how many pilots have been lost testing new technology? Go to Edwards Air Force Base (the premier flight test facility for the air force). It seems that almost every street is named for someone who died in the effort to go higher and faster. The base itself is named for a test pilot who crashed testing a flying wing. Accidents happen and people die; but we learn from those accidents and apply the lessons to future machines.

[Phobos]

Originally posted by Raven
Why didn't the shuttle have a parachute like some of the newer shuttles do or the Lunar Modles from the Apollo missions? I am really curious about this. Please help me.

The parachutes on the Apollo capsules were part of the design for re-entry. The shuttles are designed to be flown/glide to a landing. The reasons that some kind of escape pod was not provided in shuttles are (1) cost (2) the management's view that the odds of a catastrophic shuttle failure were incredibly low. Now, management is more careful, but the shuttle design is already established.

[Bear_Nenno]

Though they do not have parachutes on the shuttle itself, the astronauts have parachutes on their LES suits.
From http://neurolab.jsc.nasa.gov/launtriv.htm
LES stands for Launch/Entry Suit. The orange LES was introduced to the Space Shuttle Program after the Challenger accident, when an investigation revealed that the seven crewmembers who died in the accident had a chance of survival if they would have worn a pressure suit and would have had supply of emergency oxygen. Besides the suit, the emergency equipment that goes with the LES includes a back-pack which contains a parachute and a small life-raft. Water, chemical light sticks and flares are also part of the emergency equipment. Beneath the LES, the astronauts wear thermo underwear, which will keep them warm in case they have to bail-out into cold ocean waters.