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Seconds from Disaster – Space Shuttle Challenger (2007), National Geographic

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JonathanDunbar

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Seconds from Disaster – Space Shuttle Challenger (2007), National Geographic

Not sure if many of you have seen this episode; if not, you can view it on youtube.com.

I have been up all night fighting a bad cold/flu and have been watching the National Geographic channel.

This morning they just finished airing the above mentioned episode, and it was an eye opener for me.

First off, the ‘O’ ring failure isn’t the main reason the vehicle and crew were lost. There were many unrelated errors, miscalculations, and design flaws that all worked together to doom the mission.

We all know about Discovery that flew a year earlier at 53 Degrees Fahrenheit and how the lone Morton-Thiokol engineer, argued vehemently against flying challenger the night before citing the badly burned ‘O’ rings from Discovery’s flight in 1985.

Acclaimed quantum physicist, Richard Feynman also bought into the theory that ‘O’ rings doomed Challenger because they didn't seal do the cold weather. Well there was more and still is with shuttles…

Thiokol engineer, Roger Boisjoly, had literally screamed at his managers and NASA managers telling them that the temperature was too low, and that they would likely lose the vehicle on the pad. Thiokol management took a vote after being pressured by NASA management to give a ‘go’ for launch, they did, and then NASA saw this as a ‘blessing’ from the contractor that things were safe for launch.

OK, we all know this part… now comes the things that I didn’t know about from previous programs and articles:

Roger Boisjoly was right, and the ‘O’ Rings didn’t seal. Let me backup a bit before I continue on the ‘O’ Rings.

30 minutes prior to lift-off of Challenger, a commercial jet was passing over the launch area after being cleared by controllers at the cape. The airliner hit severe turbulence at 35k’ and had to take emergency action to get the plane down to 30k’; the plane had been hit by 150+ mph cross winds (Hurricane category 4).

NASA released weather balloons about 45 minutes prior to launch, but by the time the count was picked up again at T-9 minutes, the balloons were miles down range and could not see the air above Challenger.

Everything is going to plan. Main engine start at T-6 seconds... Roger Boisjoly is viewing the launch from atop the Vehicle Assemble Building (I know this from seeing him interviewed on other programs). Now the events that doom Challenger start: Main Engine Start. The shuttle’s main engine ignite and due to the geometry of the off center nature of the vehicles configuration, the entire assembly rocks back and forth; 3 – 4 feet deflection! It does this while the SRBs are bolted to the launch pad. This translates into a curving of the SRB stack (It still does, even with the newly designed SRBs). Any flaws in the seals between the segments are exacerbated due to this motion.

We have main engine start, 4 … 3… 2… 1… SRB ignition and LIFT-OFF lift of Space Shuttle Challenger!

At this point, the seal failed completely, and should have led to a rupturing of the casing, and the loss of vehicle, crew, and pad… but it didn’t happen that way… why?

Upon ignition of the SRBs, standing waves are set up inside the core of the motor; its natural frequency. At T+2.6 seconds, black puffs of smoke are seen coming from the lower segment of the SRB. 9 in total and they are being emitted at the SAME frequency of the natural frequency of the SRB! The ‘O’ Ring HAS failed and the black puffs are gases and propellant bypassing the seal. So why didn’t everything just stop there? Well the slag, the molten aluminum byproduct that is used to increase the ISP of the motor, filled the gap. You talk about angles watching over you. Ok, the puffs stop, the slag seals the gap, and Challenger is on her way to orbit.

Now we go back to the inaccurate weather data that NASA has about the air above the launch site. As Challenger is passing through, 30k feet, it encounters hurricane force crosswinds. This can be seen in the zigzag smoke trail that the vehicle is leaving while ascending. Challenger is FIGHTING to break free of the atmosphere. Even with the throttling down to 63% total thrust of Challenger’s main engines, the loads are severe on vehicle and the SRBs. The slag that saved Challenger 2.6 seconds after lift-off is now broken free and starts to burn through the casing, lower support strut and ET.

We know what happens after this point.

The thing that struck me while watching this program is that Roger Boisjoly was 100% correct and the vehicle should have been lost on the pad, but for a fluke bit of slag from the motor. The launch procedure of the shuttle is flawed in that the vehicle sways and this places stresses and strains on the SRB stack so that minor flaws are amplified. If NASA had real-time weather information, the launch would have been delayed.

Several things had to happen in order and I guess it was the fate of Challenger’s crew to perish no matter what.

Just thought I would share this with the forum as I thought it was very informative.

Jonathan
 
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jadebox

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I think the tragedies NASA has suffered have all been the result of a failure to imagine what could happen. Apollo 13 was saved partially because someone, before the flight, thought of using the LM as a lifeboat in case an accident crippled the command module.

But, I don't think anyone wondered what could happen if you pressurize a capsule with pure oxygen at sea level? What might happen if you launch the shuttle in very cold weather? What would happen if you ignored your own rules about foam shedding from the ET?

As in most every other tragic event, you can play with a lot of "what ifs" with the Challenger accident. For example, I've wondered what might have happened if the developers of the software had considered the effect of reduced thrust in one SRB? If the software had allowed Challenger to veer somewhat off-course instead of trying to hold the shuttle on the planned trajectory, the bracket holding on the SRB may have held long enough for the shuttle to reach an altititude where the orbiter could have detached and made an emergency landing back at KSC.

-- Roger
 

GregGleason

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Another thing about the burn-through that I read somewhere. Of the 360 degrees available on the SRB motor joint, there is only about 90 degrees or so that are going to cause a problem that may result in LOCV when you have a blow-torch at the motor field joint. However, even if the hole in the SRB was in the "safe" arc, it still had another 60 seconds or so of burn time, and some other kind of failure could have happened before SRB sep. It is just another link in the chain that led to the disaster nearly 24 years ago.

Greg
 

Mikus

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Several things had to happen in order and I guess it was the fate of Challenger’s crew to perish no matter what.
No. When the engineers say no, no "manager" in the world should ever apply pressure for a yes.

The simple fact is had management initially listened to the people who know best and waited for another day to launch, history would probably have been much different.

Good story though, hope you feel better soon.
 

luke strawwalker

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Definitely part of it, but that's not the whole story... in fact it's just one interpretation of it...

There is a layer of putty smeared on the faces of the propellant grains to help the O-rings seal... that putty was changed becausee of OSHA regulations which forbade the use of asbestos fibers, which the old putty contained, was phased out, and the new putty couldn't seal as well. The putty was there to 'slow' the hot gas impingement on the O-rings as the SRB ignited and came up to pressure. The O-rings get "blown" into position by the pressure from inside the SRB. There had been more than a few instances of O-rings not sealing properly and being burned by hot gas leakage during the flight. The putty was there to slow the hot gas down a bit before it was blown away in the SRB ignition, to give the O-rings a little more time and a little bit cooler gas to blow them into their sealed position (to wedge them between the casing field joints. Basically the O-rings had to seal within a fraction of a second-- if they didn't wedge properly and provide a near-instant seal, the incredibly hot burning propellant gases would leak at that point, and burn the O-rings to a cinder almost instantly-- hence the black puff of smoke-- that was the O-rings burning up. At that point, you get NO seal, especially when there was no asbestos particles and substandard putty, which would have been forced into the leak by the escaping gases and was supposed to help seal the O-ring off before it burned through. Because the putty had no asbestos fibers to help 'bridge the leak' the O-ring burned away VERY quickly. Slag DID help the seal, but it couldn't seal it off alone.

The 'twang' manuever is well known, and accounted for in the shuttle design. The SRB field joints (where the O-rings are) are NOT supposed to be a perfectly immobile joint-- they're designed for a certain amount of 'flex' and IIRC I remember reading somewhere recently that the SRB's actually "grow" by a few inches as they come up to pressure, because the slack is taken out of the casing joints, and the steel casings themselves actually 'stretch' a small amount, which adds up to a measurable effect because it's such a LARGE object (cumulative effect-- even water pipes in your house stretch a tiny bit when you shut the faucet off and the pressure increases in the pipe-- but it's almost immeasurable because the pipe is at most 3/4 inch diameter, usually 1/2... Now imagine the effect on a TEN FOOT diameter pipe containing not 40 PSI of water pressure, but 1,400 PSI IIRC HOT gas!)

The shuttle lifted off, and the slag started to leak, whether on it's own or from windshear we'll never know for sure. It started leaking and the leak was in about the worst place it could be-- right at the aft strut field joint, pointing parallel to the surface of the hydrogen tank wall. The leak started growing as the superheated gases cut the steel casing away like a blowtorch, and finally the strut itself was melted and cut away, and the thin tank wall of the hydrogen tank had a hole cut in it, and the aft dome of the H2 tank, holding the entire weight of the hydrogen fuel, ripped off, dumping the hydrogen. As the bottom of the tank disintegrated, the SRB broke completely free at the aft end, and torqued over, pivoting at the front SRB attach point (which is the thrust-load carrying connection 'ball hitch' joint) and the upper part of the SRB broke through the wall of the O2 tank like a giant can opener, spilling the much heavier liquid oxygen, which almost instantly mixed with the spilled hydrogen in the supersonic slipstream and created a fireball. The compromised ET came apart, the SRB's broke away and flew through the debris cloud, and the orbiter was thrown free of the disintegrated tank in the maelstrom of burning propellant and tank shrapnel in an uncontrolled tumble and nearly instantly broke up.

It was a combination of factors, but the main failure was managerial-- putting pressure on your contractors who are saying 'wait a minute' is a poor safety practice. Taking a coerced vote of consent as a 'blessing to launch' is criminal IMHO. Ignoring your own flight safety rules that say not to launch in such cold conditions, especially having seen the correlation between more seal failure and damage to the O-rings with declining launch temperatures, was another example of gross willful ignorance or negligence. Getting "go fever" because the launch had already been scrubbed a number of times because of various problems, and to serve the political aims of being able to mention the first teacher in space in the State of the Union address and garner a few political points for the agency and the program, is poor safety decision making... Feynman had it right, on the basic reason why the O-ring didn't seal due to the cold making the rubber stiff... but the underlying CAUSE was managerial practices that made decisions, conscious or unconscious, to place political and programmatic considerations ahead of safety, and gambling astronaut lives in the process...

Many of the same practices led to the Columbia disaster... and will lead to more disasters in the future no matter WHAT system is being flown, if that underlying cause does not change. As Gene Kranz said about the reason for Apollo I fire, "we saw all these problems, and NOBODY took a step back and said "wait a minute!"-- THAT is where we failed." Now we see NASA designing 'the safest launcher ever' that cannot even get it's own capsule to orbit without a 6 minute burn of the service module to achieve orbital velocity, one who's performance is already maxed out and cannot be realistically increased to any great degree, and who's anemic performance has already caused the Orion capsule to have every bit of 'nonessential' weight (capability and safety reserves) stripped out of it so that it can fit on Ares I, and NASA claiming on the basis of ONE TEST FLIGHT of a vehicle that was NOT EVEN THE FLIGHT HARDWARE (4 segment SRB with a simulator 5th segment, and simulated upperstage and capsule/tower) that the engine vibrations and thrust oscillation was more benign that expected when their numbers are showing a spread, that some flights COULD be very gentle on vibration, and others could be EXTREMELY SEVERE, yet they're taking this ONE TEST ARTICLE FLIGHT as 'evidence the problem is overblown' and it's not hard to see that the same old mistakes are being made all over again.

It takes a lot of guts to say 'wait a minute' and unfortunately it takes leadership willing to listen and objectively take a step back and realize that maybe just maybe there is a problem... I don't see that. Sad, because more lives will eventually be lost because of it... As Feynman said, "nature cannot be fooled".

OL JR :)
 

shrox

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It's almost out of service now, but I would think wrapping the ET in a 1" or so mesh of some sort before spraying on the foam would keep large chunks of foam from coming off.
 

luke strawwalker

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Another thing about the burn-through that I read somewhere. Of the 360 degrees available on the SRB motor joint, there is only about 90 degrees or so that are going to cause a problem that may result in LOCV when you have a blow-torch at the motor field joint. However, even if the hole in the SRB was in the "safe" arc, it still had another 60 seconds or so of burn time, and some other kind of failure could have happened before SRB sep. It is just another link in the chain that led to the disaster nearly 24 years ago.

Greg

I recently saw pictures of the SRB casing portion recovered from the seafloor during the investigation... the SRB's were destroyed by range safety a few seconds after the breakup when radar data showed the now unguided SRB's (their guidance computers are in the orbiter, which was gone, and so their TVC controls had no inputs, and were locked in whatever positions they were in at the breakup, which was nearly "hard over" as the engines were steered attempting to keep the stack going straight despite the SRB's massive 'side thrust' trying to push the stack off course from the leak). One of the SRB's was heading for a Florida town so range safety blew them up.

Anyway, a piece of the casing was recovered from the area of the leak-- a hole about 2-3 feet wide had been burned in the casing from the leak... it could easily been seen in the photos (don't recall ATM where I saw them, but it was in the last month or so). THAT was what caused the strut failure and ET burnthrough... a tiny hole that lets the hot gas through will get wider, letting more gas through, making the hole wider, letting even more gas through, getting wider and wider in a feedback loop...

There was no way the shuttle could survive it... the engines were almost at their gimbal limits trying to keep the stack on course and fight the side-thrust of the leak as it was-- even if the leak had been 180 degrees out from where it was, or directly opposite the ET ~120 degrees out, it still would have been a loss... the vehicle just couldn't survive the forces induced-- as the leak would have continued getting bigger with every second, the side thrust forces from it would have continued growing. The engines' TVC systems would have been 'hard over' trying to keep the stack on course, and the leak would have still been growing, and eventually would have caused the whole thing to become unstable and tumble, breaking up just as it did... that is, IF the ENORMOUS forces being transmitted through the SRB struts and orbiter connection points didn't rip the tank apart, as the forces of the engines at TVC 'hard over' tried to fight the forces of the SRB leak side-thrust pushing back through the tank against them... eventually the forces WOULD exceed the strength of the tank or attach points, even if they were intact and not compromised by the leak itself, and rip the tank apart or the connection points off the tank itself...

Designing a vehicle that required a miracle to escape from was foolish from the beginning... and escape that was IMPOSSIBLE in the first 2 minutes of flight should have NEVER been acceptable... but it is what it is... and those were the CHOICES THAT WERE MADE...

That's why it's SO IMPORTANT that the right choices are made now, and I don't see that happening... OL JR :)
 

luke strawwalker

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It's almost out of service now, but I would think wrapping the ET in a 1" or so mesh of some sort before spraying on the foam would keep large chunks of foam from coming off.
I thought the same thing... and evidently it was proposed because Wayne Hale or someone else in the shuttle program made a disparaging remark about something similar to that in a briefing or comments on NASA TV....

That was the first thing that came to mind when they were discussing the foam shedding-- why not wrap the ET in a layer of something like chicken wire or round baler net wrap (like that orange plastic construction-fence stuff) on small standoffs and then spray the foam over and through that, so it's embedded in the foam and gives it some physical strength-- if it cracks, the netting keeps the chunks connected and prevents the crack from running and the foam from ripping apart...

Oh well... nothing new under the sun... OL JR :)
 

georgegassaway

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Another thing about the burn-through that I read somewhere. Of the 360 degrees available on the SRB motor joint, there is only about 90 degrees or so that are going to cause a problem that may result in LOCV when you have a blow-torch at the motor field joint. However, even if the hole in the SRB was in the "safe" arc, it still had another 60 seconds or so of burn time, and some other kind of failure could have happened before SRB sep.
I do not think so. Look at how large of a hole that flame ate into the SRB in just a few seconds (around 10 seconds, I knew the #’s a lot more years ago but not so well now, and I do not have time today to go digging into a good source).

By the time of the break-up, there had developed a noticeable drop in thrust of the RH SRB compared to the left. So there was a thrust mismatch that on an unguided model rocket would have caused it to start to veer to the right in yaw. But since the shuttle SRB nozzles gimbal, the swiveled a bit to keep it on course. But that was with the hole getting that big and venting chamber pressure in just 10 seconds or so.

Had the flame faced outwards and not at the ET or attachment joints, it was extremely doubtful that the shuttle could have remained under control for another 60 seconds. Perhaps not another 30 seconds, maybe not even another 10 seconds. There would have been a more and more severe thrust drop as the hole got bigger. And keep in mind the hole’s size (in surface area terms) was getting bigger exponentially, not linearly. The chamber pressure would have dropped more and more, and the SRB nozzles would have deflected more and more to keep the shuttle on course. Until, eventually, the SRB nozzles would have exceeded their gimbal travel and then the shuttle would have yawed to the right, out of control.

At some given combination of yaw angle of attack thru the air, and the dynamic pressure at the altitude the shuttle would have broken up. Perhaps the orbiter’s vertical tail (rudder) first as it is not designed to take much of a side load (yaw). Such as that Airbus airliner that crashed in New York 1-2 months after 9/11 when the pilots yawed it too far and it broke its vertical tail off. Or perhaps no precursor like that, just the whole stack may have ripped apart such as the ET breaking up and letting everything else go free.


BTW - the orbiter Challenger did not “blowed up”. The first structural damage to Challenger was when the RH SRB pivoted into the right wing and broke the wing off. Then when the ET broke up, causing the fireball, Challenger was left flying at a few thousand miles per hour with no right wing (but otherwise briefly still intact), and pitched nose down to the airflow. It reached an angle of attack to the airflow that caused Challenger to break up structurally from aerodynamic forces.

If you ever see the video again ,pay attention to this: The side view when it “blew”. The fireball happens and the camera angle quickly changes to a different view showing the expanding fireball and SRB’s flying free. A second or so BEFORE that camera angle changed, you can see Challenger STILL intact (could not see the missing right wing on the other side), starting to pitch nose down. So it was still intact after the fireball started (other than the right wing gone). Some time very shortly after that camera angle changed is when Challenger was ripped apart by supersonic aerodynamic forces, not by an “explosion”.

I have never seen a replay of that side view continuing on past when the angle changed to the other camera. I have often wondered if the view had not been changed, if it would have been possible to see Challenger break up. Or it may be that the expanding fireball would have hidden it from view.

I took note of the aerodynamic break-up on about the 10th network TV replay I saw that day (I did not have a VCR then). I knew that the reports that “the crew was vaporized instantly because the explosion had the power of a nuclear bomb” was bull-stuff. Even if almost nobody could notice that Challenger started to pitch down instead of being “vaporized” in that instant, the still-intact SRB’s flying along should have been sufficient evidence that there was no extreme explosion, certainly not of the nuclear blast and vaporized crew type.

What the news media was going on was previous NASA produced shuttle news reference info that referred to the ENERGY expended during a flight into orbit as being equal to that expended in a nuclear explosion. That is a totally different thing (accelerating a shuttle to orbital velocity over a span of 8.5 minutes, versus a nuclear bomb detonating in microseconds). Also, even if a perfectly mixed blend of Liquid Oxygen and Liquid Hydrogen could create quite a blast, much like a fuel-air explosive does, the Challenger accident did not mix the Lox and Hydrogen in such a perfect manner (If a fuel-air bomb does not disperse the fuel into a fine mist just right, there will be more fireball than big boom). So it was a lot more “fireball” than “explosion” (I do not think even the BATF would have called it an explosion!). But when the news media started to report it that way, it was in NASA’s self-interest to NOT correct the media since “crew vaporized” was a better public relations thing “than crew not vaporized, crew might have been aware of what was going on, and crew remains out there in the Atlantic somewhere” would have been for NASA?

So, I was not surprised at all when 6-8 weeks later NASA announced they’d found the crew cabin on the ocean floor, mostly intact but of course crushed by impacting the water. And of course NASA had to have known within 1-2 days, if not even hours of the accident that the cabin had ripped off from Challenger mostly intact, and tumbled all, the way down to the ocean. But for all intents and purposes NASA was in a “news blackout” for many days, and kept that fact hidden (cabin thrown free, tumbling, to the ocean, crew not vaporized as NASA allowed the news media to report) until the day they announced the recovery of crew remains.

- George Gassaway
 
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kramer714

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I thought the same thing... and evidently it was proposed because Wayne Hale or someone else in the shuttle program made a disparaging remark about something similar to that in a briefing or comments on NASA TV....

That was the first thing that came to mind when they were discussing the foam shedding-- why not wrap the ET in a layer of something like chicken wire or round baler net wrap (like that orange plastic construction-fence stuff) on small standoffs and then spray the foam over and through that, so it's embedded in the foam and gives it some physical strength-- if it cracks, the netting keeps the chunks connected and prevents the crack from running and the foam from ripping apart...

Oh well... nothing new under the sun... OL JR :)
There are issues in adding reinforcement to the foam, one big one being the chance of a progressive failure where the foam peels off in a large piece. Small unreinforced foam isn't good, larger reinforced foam is far worse.

Adding a skin over the foam can be done but it needs to be well integrated into the entire tank design. Remember these tanks are pretty dynamic between the loads, tank pressure (just the head pressure of fluids is pretty large), and thermal effects, things can move around a bit, any insulation needs to be able to respond to that.
 

luke strawwalker

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There are issues in adding reinforcement to the foam, one big one being the chance of a progressive failure where the foam peels off in a large piece. Small unreinforced foam isn't good, larger reinforced foam is far worse.

Adding a skin over the foam can be done but it needs to be well integrated into the entire tank design. Remember these tanks are pretty dynamic between the loads, tank pressure (just the head pressure of fluids is pretty large), and thermal effects, things can move around a bit, any insulation needs to be able to respond to that.
Oh, yeah...

If it was easy it wouldn't be rocket science... just figuring out the weight of a foam reinforcement system would probably rule it out... you could either have a payload or foam reinforcement, not both...

Then you've fundamentally changed the design and would have to completely recertify the tank; all told would probably be a billion-dollar project. SO I see why NASA chose not to go down that road for a vehicle that was being phased out. The time to make hard decisions is when something's in the design phase, not after it's built and certified.

Anyway, I guess I should have clarified... I'm sure the thermal expansion and contraction of the tank plays a part as well, since a structure that huge is going to shrink by a few inches when the supercold liquid hydrogen fills the tank, etc. I read that another factor is liquid air if there are any 'large' bubbles in the foam-- the hydrogen is SO cold that the air in the bubble imbedded in the foam actually turns to liquid, which has MUCH less volume than the equivalent gas at sea level pressure, so the atmosphere tends to 'crush' the foam down around the liquid air in the bubble to remove the extra space. This weakens the foam. Then later in flight, as the speed increases and the air heating of the tank and foam increases, the liquid filled air bubble revaporizes, inflating the bubble back up again, tending to crack the foam from the expanding pressure, and possibly causing the bubble to burst from the internal pressure which is now much higher than the low ambient pressures at altitude, and the foam is significantly more likely to fail due to being 'flexed' twice- in and back out again...

It's a sticky situation.. and why it took them a couple years and hundreds of millions to get the 'fix' that they have... (which still ain't exactly "FIXED fixed")

Later! OL JR :)
 

bobkrech

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...I took note of the aerodynamic break-up on about the 10th network TV replay I saw that day (I did not have a VCR then). I knew that the reports that “the crew was vaporized instantly because the explosion had the power of a nuclear bomb” was bull-stuff. Even if almost nobody could notice that Challenger started to pitch down instead of being “vaporized” in that instant, the still-intact SRB’s flying along should have been sufficient evidence that there was no extreme explosion, certainly not of the nuclear blast and vaporized crew type.

What the news media was going on was previous NASA produced shuttle new reference info that referred to the ENERGY expended as being equal to that in a nuclear explosion. That is a totally different thing. Also, even if a perfectly mixed blend of Liquid Oxygen and Liquid Hydrogen could create quite a blast, much like a fuel-air explosive does, the Challenger accident did not mix the Lox and Hydrogen in such a perfect manner (If a fuel-air bomb does not disperse the fuel into a fine mist just right, there will be more fireball than big boom). So it was a lot more “fireball” and “explosion” (I do not think even the BATF would not have called it an explosion!). But when the news media started to report it that way, it was in NASA’s self-interest to NOT correct the media since “crew vaporized” was a better public relations thing “than crew not vaporized, crew might have been aware of what was going on, and crew remains out there in the Atlantic somewhere” would have been for NASA?

So, I was not surprised at all when 6-8 weeks later NASA announced they’d found the crew cabin on the ocean floor, mostly intact but of course crushed by impacting the water. And of course NASA had to have known within 1-2 days, if not even hours of the accident that the cabin had ripped off from Challenger mostly intact, and tumbled all, the way down to the ocean. But for all intents and papooses NASA was in a “news blackout” for many days, and kept that fact hidden (cabin thrown free, tumbling, to the ocean, crew not vaporized as NASA allowed the news media to report) until the day they announced the recovery of crew remains.

- George Gassaway
As I watched the video replays on the day of the accident it appeard the crew cabin was basically intact after the Challenger disintegrated. You could see the crew cabin in free fall after the disintegration and since it was one of the strongest part of the vehicle, I thought it would be highly unlikely that the crew was killed when the Challenger disintegrated, but rather died on impact with the water.

NASA management saw the same videos and probably came to the same conclusion. They were probably shocked when they realized what happened and immediately went into a CYA mode as their decision to launch was swayed by knowledge that the evening's State of the Union Address highlighted the teacher in space project, rather than a sound engineering judgement...

Bob
 

SCE to AUX

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For those who have never read it, here's an interesting (and disturbing) article from the Miami Herald, anout the recovery of the Challenger crew, and how NASA tried to hide the truth:

http://www.lutins.org/nasa.html
 

luke strawwalker

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For those who have never read it, here's an interesting (and disturbing) article from the Miami Herald, anout the recovery of the Challenger crew, and how NASA tried to hide the truth:

http://www.lutins.org/nasa.html
VERY interesting read... thanks for the link SCE...

Disturbing but yet COMPLETELY typical for a government agency... There's one set of rules for them and another set for everyone else...

Later! OL JR :)
 

Viperfixr

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Disturbing but yet COMPLETELY typical for a government agency... There's one set of rules for them and another set for everyone else...
I've followed this thread closely, and have found many of the posts very interesting regarding NASA culture and methods. However, the broad brush statement above "typical for a government agency" is unnecessary. Not everything is a conspiracy, and not everything in the government responds the same way. Disclosure up front: I am employed by a "government agency."

The US government is a huge animal with many arms, fingers, etc. I've been involved investigating a few USAF crashes involving fatalities or serious injury, and those are tough things to be around. When things go wrong in this regard, it's usually a single person (was it Abbey in this case?) making an emotional, selfish decision that is thought to be in the government's best interest, but often not. In these situations, there's an immediate need to clamp down on any conjecture or supposition not based on facts or released in the correct way. Anything else gets in the way of the investigation and potentially harms the next of kin (family) with falsehoods.

There also is a huge concern for not making the tragedy any worse on the families than it already is, and I am betting that was a large part of what NASA tried to do. Plus, a local ME probably lacked the same specialization as the military pathologists called in. Perhaps well intentioned, but it became a problem because there was no transparancy. That's not government policy, but rather a decided course of action from a single employee in a leadership role. Mike Mullane's book "Riding Rockets" covers this NASA time frame from an insider's perspective--the astronaut corps was as in the dark as everyone else.

There is a significant "fog of war" when in the midst of a high tension issue--it's just not that simple or broad brushed. People seem to love conspiracies, but the reality is often not that interesting or mysterious. Those astronauts were tragically gone no matter what the course of action after the tragedy.
 
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SCE to AUX

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I would also add that we can expect much the same (or even worse) when one of the private sector space operations suffers their first fatality (and they certainly will). Seeking to control the flow of potentially embarrassing information and spin media coverage in a favorable direction is a characteristic of ANY bureaucratic organization, not just government agencies.

At least with government cover-ups, the truth EVENTUALLY comes out. Once private, corporate interests are involved, things like FOIA, sunshine laws, etc. no longer apply. We will be told only what they want us to know, when they want us to know it.
 

Mikus

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Mike Spillane's book "Riding Rockets" covers this NASA time frame from an insider's perspective--the astronaut corps was as in the dark as everyone else.
Mike Mullane. An excellent read I highly recommend, but it's not very complimentary of NASA management. Go figure. :eek:
 

wilsotr

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Now we see NASA designing 'the safest launcher ever' that cannot even get it's own capsule to orbit without a 6 minute burn of the service module to achieve orbital velocity, one who's performance is already maxed out and cannot be realistically increased to any great degree, and who's anemic performance has already caused the Orion capsule to have every bit of 'nonessential' weight (capability and safety reserves) stripped out of it so that it can fit on Ares I, and NASA claiming on the basis of ONE TEST FLIGHT of a vehicle that was NOT EVEN THE FLIGHT HARDWARE (4 segment SRB with a simulator 5th segment, and simulated upperstage and capsule/tower) that the engine vibrations and thrust oscillation was more benign that expected when their numbers are showing a spread, that some flights COULD be very gentle on vibration, and others could be EXTREMELY SEVERE, yet they're taking this ONE TEST ARTICLE FLIGHT as 'evidence the problem is overblown' and it's not hard to see that the same old mistakes are being made all over again.
What you are seeing is a spacecraft and launch vehicle being designed in broad daylight. Along with it come all the technical issues that accompany any major development program. Nothing more. Ask the Boeing guys about the 757 sometime ... nothing significant is easy.
 

wilsotr

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Mike Mullane. An excellent read I highly recommend, but it's not very complimentary of NASA management. Go figure. :eek:
Good book! He wasn't very complimentary of Air Force management, either. :)
 

wilsotr

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I've followed this thread closely, and have found many of the posts very interesting regarding NASA culture and methods. However, the broad brush statement above "typical for a government agency" is unncessary. Not everything is a conspiracy, and not everything in the government reponds the same way. Disclosure up front: I am employed by a "government gency."
It always interests me, when I read things like this Miami Herald article closely, how many of the really sensational quotes are attributed to "unnamed sources" and "another person" and "someone else close to the project."

Read this one again, carefully, and look for that ....
 

Viperfixr

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Good book! He wasn't very complimentary of Air Force management, either. :)
He wasn't very complimentary of how the USAF took care of their astronauts, or of space. A lot has changed since then! USAF is all about space. Heck, my next door neighbor is a space control Airman (big A). Take a look at what the US Air Force plans to fly soon
:
 

dave carver

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It's almost out of service now, but I would think wrapping the ET in a 1" or so mesh of some sort before spraying on the foam would keep large chunks of foam from coming off.


I made this suggestion years ago to NASA to use monofilament birdcatching netting to hold the foam on the tank but did they listen? NOOOOOOOO:rolleyes:
 

Fred22

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I've followed this thread closely, and have found many of the posts very interesting regarding NASA culture and methods. However, the broad brush statement above "typical for a government agency" is unncessary. Not everything is a conspiracy, and not everything in the government reponds the same way. Disclosure up front: I am employed by a "government gency."

The US government is a huge animal with many arms, fingers, etc. I've been involved investigating a few USAF crashes involving fatalities or serious injury, and those are tough things to be around. When things go wrong in this regard, it's usually a single person (was it Abbey in this case?) making an emotional, selfish decision that is thought to be in the government's best interest, but often not. In these situations, there's an immediate need to clamp down on any conjecture or supposition not based on facts or released in the correct way. Anything else gets in the way of the investigation and potentially harms the next of kin (family) with falsehoods.

There also is a huge concern for not making the tragedy any worse on the families than it already is, and I am betting that was a large part of what NASA tried to do. Plus, a local ME probably lacked the same specialization as the military pathologists called in. Perhaps well intentioned, but it became a problem because there was no transparancy. That's not government policy, but rather a decided course of action from a single employee in a leadership role. Mike Mullane's book "Riding Rockets" covers this NASA time frame from an insider's perspective--the astronaut corps was as in the dark as everyone else.

There is a significant "fog of war" when in the midst of a high tension issue--it's just not that simple or broad brushed. People seem to love conspiracies, but the reality is often not that interesting or mysterious. Those astronauts were tragically gone no matter what the course of action after the tragedy.
This post makes a heck of a lot of sence to me.
Cheers
fred
 

JonathanDunbar

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Found this information from one of the studies done on Challenger, interesting reading:

PART 1:

Case Study 1
The Challenger Space Shuttle disaster
and the Solid-Fuel Rocket Booster
(SRB) project
Overview
On 28 January,1986 the Challenger space shuttle blew up 73 seconds after
launch. Seven lives and three billion dollars worth of equipment was lost.
The Challenger accident was the result of a faulty sealing system which
allowed exhaust flames from the Solid-Fuel Rocket Boosters (SRB) to vent
directly on the external tank, rupturing the tank and causing the explosion.
NASA identified the failure due to the improper sealing of the O-rings, the
giant black rubber loops that help seal the segments of the SRBs. The O-ring
is made of a fluoroelastomer, which seals the joint between two solid rocket
booster sections. An elastomer is a material that can be deformed
dramatically and recover its shape completely. A rubber band is an example
of an elastomer.
In almost half of the shuttle flights there was O-ring erosion in the booster
field joints. The launch took place in untested temperature conditions and in
spite of serious warnings on the part of the engineers of Thiokol, the
company that manufactured the SRBs. The sequence of events that led to
the unfortunate events is examined in order to draw the necessary
conclusions.
NASA was very anxious to proceed with the launch for a variety of reasons
including, economic considerations and political pressure. To justify its
budget NASA had scheduled a large number of missions in 1986. It was
vital for the Challenger to be launched so that there would be enough time to
refurbish the launch pad to prepare it for the next launch. The European
Space Agency was providing added competition and there was political
pressure for the Challenger to be in space when the president of the US gave
the State of the Union address.
There were plenty of advanced warnings regarding the SRBs, from previous
missions. Concerns had been voiced by Thiokol, the SRB manufacturing
company, as to whether the fatal launch should have taken place. The cold
weather, some of the coldest in Florida history, provided uncharted waters
for the operation of the SRBs.
What went wrong? Why did NASA launch in spite of the evidence and
warnings from Thiokol engineers? Should the launch have been cancelled?
Challenger space shuttle: A project success or a program
failure?
At first sight, the Challenger incident can only be regarded as a failure. Loss
of life and loss of equipment worth billions of dollars can only be associated
with bad news. The television pictures of the Challenger’s explosion made
their way round the world and were broadcast over and over as the leading
news story and will indelibly remain in people’s minds for many years to
come.
Before arriving at a verdict about the Challenger explosion, it is necessary to
examine the various events that led to NASA’s twenty-fifth shuttle mission,
which proved to be fatal for the Challenger. Is it possible that the SRB
project was a success, while the overall program was a failure?
Background information
To better understand the conditions that existed at the time of the launch
some background information is presented below that includes:
 Technical information relating to the SRB project.
 Description of the program environment.
 Management restrictions associated to funding issues.
 Invisible political pressure.
The reusable space shuttle
In the post-Apollo era of the lunar landing the idea of a reusable space
shuttle was born. The goal was to make access to space a routine matter,
similar to flying an airplane. The space shuttle had to be reusable and
economical to develop and operate. The design of the space shuttle was
shaped by engineering considerations but also by pressure from the White
House and Congress to reduce the cost.
There are three main components of a space shuttle:
1. The orbiter.
2. The external fuel tank.
3. The solid-fuel rocket boosters.
The orbiter is the vehicle which transports the astronauts into space. The
orbiter is propelled by thrusters at the back of the orbiter and the purpose of
the external fuel tank is to pump a combination of hydrogen and oxygen fuel
to the orbiter’s thrusters. The SRBs provide the majority of the thrust in
order to place the orbiter in orbit. When the orbiter is close to orbit, the
SRBs detach and the orbiter is propelled only by the thruster. The SRBs fall
to earth, where they are collected to be reused in future missions. When the
orbiter is in orbit the external fuel tank is also detached. The external fuel
tank is not reused.
SRB history
The SRB is at the center of the Challenger disaster and its history needs to
be examined. The SRB is a scaled up version of a Titan missile which had
been used successfully for years. In general, solid-fuel rockets produce
much more thrust than liquid-fuel rockets. One of their drawbacks is that
once the solid-fuel rocket has been ignited they cannot be turned off or even
controlled. It is therefore extremely important that the SRBs are properly
designed, because if something goes wrong there is no second chance.
Each of the two SRBs was 149ft (45.42m) long and 12ft (3.7m) in diameter.
Before ignition each booster rocket weighs 2 million pounds (0.9 million
kilograms.) The shuttle’s two solid-fuel booster rockets provide the main
power to lift the orbiter and its external liquid-fuel tank to a height of around
28 miles (45 km.)
The life of each booster is around two minutes. When the SRBs are nearly
empty of fuel they disengage from the space shuttle and will eventually fall
into the Atlantic Ocean where they will be collected for use in a future
mission.
A chronological history of the SRB used in the Challenger space shuttle is
indicated below:
 1974: The contract for building the SRBs was awarded to Thiokol.
 1976: NASA accepted the SRB design.
 1977: Joint rotation problems were discovered.
 1981: O-ring erosion detected after the second shuttle flight.
 1985: The worst problem relating to the O-rings was exhibited after
the January 24, 1985 shuttle flight.
 1985: On August 19, 1985, four months prior to the Challenger
disaster, the NASA management was briefed on the booster
problems.
 1986: On January 27, 1986, a few hours prior to the launch, a
teleconference took place between NASA and Thiokol to discuss the
effects of cold temperature on the SRB performance.
Events leading to the launch
The decision by NASA to launch the Challenger space shuttle on 28
January, 1986 was controversial at best. There were plenty of warning signs
during the launches that preceded the launch. In November 1981, after the
shuttle’s second mission, the O-rings seemed to have been eroded by hot
gasses. The January 24, 1985 launch took place in similar cold-weather
conditions as the fatal launch of January 28, 1986. After the mission the
booster joints were examined by engineers at Thiokol who found traces of
soot and grease caused by passage of hot combustion gases past the O-ring
before it has completely sealed the joint. As a result Thiokol started
studying the resiliency of O-rings at low temperatures. In July 1985 Thiokol
ordered steel billets which would be used for a redesigned case field joint.
The steel billets were not ready at the time of the Challenger launch.
The events a few days prior to the fatal launch are worth looking into. The
Challenger was first scheduled to be launched on 22 January at 15:43. This
was rescheduled for 23 January and then again rescheduled for 24 January.
The launch was reset for 25 January because of bad weather at abort landing
site in Dakar, Senegal. Launch was rescheduled for 27 January at 09:37 due
to the prediction of unacceptable weather at Kennedy Space Center. Launch
was delayed for 24 hours when ground servicing equipment hatch closing
fixture could not be removed from orbiter hatch.
In a conference call the night of the 27 January, 1986, engineers at Thiokol
recommended against launching below 53oF, which was the coldest
temperature at which a previous flight had launched. On the night before the
launch, the temperature was expected to be as low as 18oF, more than 30
degrees colder than any other launch. Thiokol engineering was overruled by
its management and the go-ahead was given to proceed with the launch.
 

JonathanDunbar

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PART 2:


Second by second account of the Challenger launch
At 11:38 EST on January 28, 1986, the Challenger took off from the launch
pad at Kennedy Space Center in Florida. The key events until its explosion
are indicated below:
 0.68 sec after ignition: Black smoke coming from bottom field joint
of the right SRB, indicating that the rubber O-rings were being
burned.
 2.70 sec: Last puff of smoke seen.
 45.00 sec: Three bright flashes shot across the Challenger’s wings.
Each of the flashes lasted 1/13 of a second and were unrelated to the
events leading to the explosion.
 58.80 sec: With enhanced film a flame was seen coming from the
right SRB.
 59.30 sec: Without enhanced film the flame could be seen increasing
in size and beginning to push against the external tank.
 64.70 sec: The first sight that the flame was hitting the external tank.
There is also a change in the color of the flame indicating that the
flame was being produced by the mixing with another substance. In
this case the other substance was liquid Hydrogen stored in the
external tank.
 72.00 sec: Within the next 2 seconds there is sudden chain of events
that destroyed the Challenger and killed its crew onboard. The
Challenger was traveling at a speed of Mach 1.92 and a height of
46,000 feet.
 73.62 sec: The last transmission from the Challenger.
Causes of the Challenger accident
A commission was appointed by the president of the US to investigate the
accident. The Rogers Commission as it was called addressed the problems
in the following two areas:
1. Mechanical problems.
2. Administrative problems.

The mechanical fault that led to the explosion of the Challenger was
identified in the right solid rocket booster. A field joint between the sections
of the SRB allowed exhaust flames to leak through the field joint. A field
joint is a joint between the sections of the SRB that was assembled in the
field at the Kennedy Space Center during the final construction of the
booster. The leaked flames impinged upon the external fuel tank. The
flames managed to penetrate and ignite the fuel in the external fuel tank,
causing the explosion.


The failure of the sealing system on the field joint that led to the explosion
of the Challenger was a result of the combination of four problems:
1. The tendency for holes to form in the putty which protected the seals
from the high temperature exhaust gases.
2. The decomposition of the seals due to contact with the hot exhaust
gases.
3. An instantaneous increase in the size of the gap between mating
sections of the booster caused by the high internal pressures of the
SRB.
4. The inability of the seal to quickly respond to the changing gap size
during low temperature operating conditions.
The Administrative problems were more profound due to the simple fact
that all mechanical problems associated with the field joint had been
identified by the Thiokol engineers. All problems were identified as a
potential risk, but there was difficulty in communicating these problems to
the managers who were responsible for the launch. The decision to launch
the Challenger despite the identified risks was a combination of poor
communication and a difference in the evaluation of the risk.
Risk issues
Risk is largely subjective. If it wasn’t subjective, it would be possible to
accurately identify the risk and account for its effect, or even take the
appropriate measures for eliminating the risk.
In the case of the SRB project, risk was assessed mainly by two categories
of people, the engineers and the managers. Engineers based their risk
assessment largely on their technical experience and facts. Managers were
more inclined to take a risk due mainly to the fact that they were a bit
removed from the technical issues and due to the fact that their job was to
ensure that business proceeded without delays.
It was clear that engineers and managers were not of the same view
regarding the risk associated with the use of the O-rings at untested low
temperatures. Managers were happy to accept low temperature tests that
were performed in laboratory conditions, while on the other hand engineers
dismissed these tests as unrealistic.
There was no way to get rid of the subjective nature in evaluating risk since
at both NASA and Thiokol there was no method for quantifying risk. On the
one hand you had the engineers saying “I believe there is a big danger” and
on the other hand the managers were saying “I believe that there is a smaller
danger.”
It may be amazing to note that NASA did not employ a quantitative method
of risk assessment for such a high-profile project. The main reason is the
expense associated with the data collection and statistical model generation.
NASA employed no engineers trained in statistical sciences.
Thiokol managers held misconceptions regarding the safety issues related to
the O-rings. They believed that the SRBs could be operated at temperatures
ranging between 31oF and 99oF, although Thiokol engineering noted that
there was no real-condition testing at these temperatures. The debate
centered mainly on the lowest temperatures at which the SRBs could
operate, since neither Thiokol nor NASA had official launch data that
matched the conditions of the fatal launch.
There were other reasons who contributed to the optimistic approach by
management compared to that by engineering. There was clear evidence that
there was O-ring erosion on previous shuttle flights. Since this did not give
rise to any catastrophic results, a false sense of security was developed.
O-ring erosion was therefore something to be expected. The fact that there
were relatively few accidents at NASA re-enforced the subjective approach
to risk assessment. Since the risk assessors were right on so many occasions,
what were the chances of being wrong on this occasion?
The difference in the manner that risk is assessed by managers and
engineers lies primarily in their objectives. Managers are in the business of
management or administration, while engineers have more interaction with
the day-to-day activities. Managers needed to keep the shuttle program
going in order to be able to justify their budget and were willing to take
bigger risks.
Communication issues
The Roger Commission identified a breakdown in the communication as a
contributing factor in the Challenger accident. Important information was
not from Thiokol engineering regarding the SRBs did not find its way to the
appropriate people at NASA in charge of the launch.
The management structure that was followed at both NASA and Thiokol
was that followed by the traditional organization, with a single chain of
command. Every employee could report to his manager and his manager to
his manager and so on. This reporting structure is inefficient and is not
suited for communicating important issues quickly to the appropriate
management level for consideration.
As indicated in figure Case Study 1-1, the only way that a Thiokol engineer
could voice his concerns to the NASA officials who were directly
responsible for the launch, was first through the Thiokol hierarchy and then
through the NASA hierarchy. The management procedures that were in
place did not allow a Thiokol engineer who knew the ins and outs of the
SRB to communicate with the launch manager at NASA.
Figure Case Study 1-1
In the months preceding the launch, the Thiokol engineers warned about the
impending danger. An excerpt from one of the communications summarizes
their position.
“The secondary O-ring cannot respond to the clevis opening rate and may
not be capable of pressurization. The result would be a catastrophe of the
highest order – loss of human life. …It is my honest and very real fear that
if we do not take immediate action to dedicate a team to solve the problem
with the field joint having the number one priority, then we stand in
jeopardy of losing a flight along with all the launch pad facilities.”
Even on the eve of the launch, the Thiokol engineers warned against
launching the Challenger below 53oF, which was the lowest temperature
that a launch had taken place. Their recommendation was not followed.
It is apparent that Thiokol engineering was aware of the problem associated
with sealing the field joint. To make matters worse Thiokol engineering felt
that Thiokol management had an inaccurate understanding of the
importance of the O-ring problem.
Thiokol
Management
Thiokol
Engineering
NASA
Management
NASA
Engineering
Thiokol NASA
White
House
 

JonathanDunbar

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PART 3 (FINAL):


In a conference call the night of the 27 January, 1986, engineers at Thiokol
recommended against launching below 53oF, which was the temperature at
which a previous flight had launched. On the night before the launch
temperatures were expected to be as low as 18oF, more than 30 degrees
colder than any other launch. Thiokol engineering was overruled by its
management and the go-ahead was given to proceed with the launch. Yet no
Thiokol engineer risked his job by picking up the telephone to inform the
NASA manager responsible for the launch that the launch should be
cancelled.
The communication inside NASA and Thiokol regarding the SRB project
resembled in many cases the “telephone game” played by children. In the
telephone game a child whispers to his neighbor child a message, who in
turn whispers the message to the next child and so on until the message
reaches the last child. By this time the original message has undergone a
significant change, due mainly to inefficiency.
Information that was passed up the hierarchy at Thiokol to NASA officials
regarding the SRB was distorted to fit the interests of management. In many
cases the information was silenced and lost in the chain of command. Basic
information regarding the SRBs and the fact that Thiokol engineers opposed
the launch of the Challenger never reached the NASA officials responsible
for the launch.
Discussion points
1. Identify the project.
2. Identify the players.
3. Chronological account of events.
4. Description of environment on the day of the launch.
5. Pressure to launch: There was a push to have 15 shuttle launches in
1986 and 24 launches by 1990.
6. Communication issues: Communication within Thiokol and between
Thiokol and NASA. Management issues where reporting could only
be done one level up.
7. Pressure to launch so that the launch schedule would proceed
uninterrupted.
8. Political pressure to launch so that Challenger was to be in orbit
while President Reagan gave the State of the Union address.
9. Risk: There was no process in place to quantify risk. Managers and
Engineers had differing views based largely on their objectives.
10. Identify the interdependencies between the project and the project
environment.
11. Was NASA taking an acceptable risk?
12. Why did NASA managers together with Thiokol managers overrule
Thiokol engineers?
13. Was there miscommunication between NASA and Thiokol?
14. What were the causes of the accident?
15. Should NASA have proceeded with the launch?
16. Was there ample information to warrant the cancellation of the
launch?
17. Was the SRB project a success or a failure?
 

georgegassaway

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In a message awhile back, the question arose what if the leak had not been aimed at the ET or the attachment fittings, but in a different radial direction.

Well, that has been covered by others, and myself. But I failed to mention why it was so likely that the leak WOULD face towards the ET, and even why it was so likely it would be the right SRB and not the left to fail.

Because while the foam on the ET does provide insulation, it is not 100% perfect. There is a blanket of “cold air” around the ET, due to the thermal loss from the cryogenic temperatures of the Liquid Oxygen and Liquid Hydrogen.

The air temperature at KSC was 36 degrees. Well, it was many degrees colder than that near the ET and the SRB's. That morning, the wind at the pad was coming mostly from the left side of Challenger, to the right side. So, the left SRB was not quite as cold as the right SRB because the blanket of “cold air” from the ET was blown by the wind more towards the right SRB. And regarding the right SRB, the absolute coldest regions on it (looking at a top view) was the region closest to the ET. And indeed within that arc of maximum coldness (due to the blanket of cold coming off the ET itself) is where the leak occurred. The coldest reading was 12 degrees. TWELVE! As in 24 degrees colder than 32. As in 20 degrees below freezing.

In one of the reports, perhaps the Challenger commission report itself, the above was described (which is how I found out about it). IIRC including some computer graphics showing the relative temperatures due to the blanket of cold and how the wind had an effect.

BTW - real-time, NASA *DID* know of the temperatures being extra-cold near the ET. For one, that is the nature of all shuttle launches. Shortly before launch, a special crew is sent to the pad to inspect the fueled shuttle, looking for leaks, ice, and anything unusual. They have very accurate temperature sensors mounted to poles, and they move the sensors close to various spots to take readings. Real-time, they got those readings on Challenger. This indeed is where some of the data came from in the report, actual temperature readings at various locations that were far below the air temperature. And this is where the coldest reading of 12 degrees came from.

But, none of the pad crew knew anything of the Thiokol engineer warnings, and IIRC only one person at KSC knew about the Thiokol engineer warnings of the effects of cold on O-rings.

Also, I do not recall ever hearing that the Thiokol engineers knew of this blanket of cold air phenomenon (they may have just thought that air temp and the temps at the joints were the same thing). Otherwise, if the engineers had realized that the O-rings would actually be TWENTY DEGRESS BELOW FREEZING (12 degrees) at liftoff, maybe the fickle one that “took off his engineering hat and put on his manager’s hat” might have refused to take off his engineering hat and not roll over to go along with signing off on the launch. Certainly none of the engineers knew of the 12 degree cold readings at the pad before launch since this heated discussion had happened the night before, they lost, and that was the end of THAT. There was no requirement for Thiokol engineers to be available for consult real-time in the hours before launch (managers maybe, but how useful is a manager who does not know the engineering and worst of all over-rides what his engineers tell him???)

But I think in some ways such an accident was probably inevitable. Had they not flown Challenger in the cold that morning, they would have lost some other mission later on due to O-ring problems. The original joint design was poor and NASA would never get the funds from congress to pay for an SRB redesign without some shattering reason. And even if NASA did, they would not have stopped flying for the years it would have taken to have new SRB’s designed and built (only took about 1.5 years after the Challenger accident, but then there were huge incentives to get it done, with lots of money thrown at it quickly, in order to resume flying).

- George Gassaway
 
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