Author Topic: Challenger STS-51L  (Read 166925 times)

Offline Hotol

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Re: Challenger STS-51L
« Reply #80 on: 01/30/2006 12:55 pm »
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SimonShuttle - 30/1/2006  4:18 AM

Why did only one booster fail if it was too cold for the o-rings? Did the rings survive on the other SRB?

Not a bad question, but I think it was pure luck both didn't blow on the pad.

Offline Dobbins

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Re: Challenger STS-51L
« Reply #81 on: 01/30/2006 01:27 pm »
A better question would be why didn't the other 5 joints fail. Each 4 segment SRB has 3 o-ring joints and only 1 of the 6 joints failed. In addition the one that failed did so at a point where the outgassing would strike the ET, a failure at a different point would have directed the flame away from the ET. There was an element of bad luck in addition to the bad design and practices.

John B. Dobbins

Offline Jackson

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Re: Challenger STS-51L
« Reply #82 on: 03/20/2006 09:21 am »
Hi. New to this excellent site. This really moved me, so very sad to hear some of the things we didn't get to hear publically before. RIP.

Offline Jamie Young

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Re: Challenger STS-51L
« Reply #83 on: 03/20/2006 05:15 pm »
Welcome to the site. Not a lot can be added to this thread. All very sad.

Offline Jackson

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Re: Challenger STS-51L
« Reply #84 on: 03/20/2006 08:49 pm »
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Jamie Young - 20/3/2006  12:15 PM

Welcome to the site. Not a lot can be added to this thread. All very sad.

I agree, but it's also something that needs to be known so as to add respect to the brave astronauts.

Offline TheMadCap

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Re: Challenger STS-51L
« Reply #85 on: 03/23/2006 12:02 am »
I was 14 years old and in Jr. High school at the time.

By that time, it was sort of rare to show shuttle flights on TV, but the Teacher in Space Program was all over the place. I remember being very much aware of the significance of sending a civilian into space.

I remember getting to Art class just after lunch that day, and everyone in class, a few teachers and students from other classes huddled around the television. I remember they just kept showing that replay over and over. Several people, including my Art teacher were openly weeping. I ended up leaving the room to try and make some sort of sense out of it. To go from total elation at seeing Columbia on STS-1 to this was a little more than I could bear. I cannot even begin to imagine the horror of the loved ones in attendance.

I also think it was a complete chance event that she didn't blow up on the pad. Roger Boisjoly has been quoted as saying he breathed a sigh of relief when Challenger got off the ground. I can't recall if they were able to recover any of the pieces from the other booster, I am sure someone here knows. For some reason, I want to say that the aft field joint was most affected by the o-ring problem; I remember hearing that the engineers at Thiokol seemed to focus on that particular section from earlier flights.

I recently saw a special on NGC that suggested a theory (?) about why the leak didn't cause an instant catastrophic event. Film evidence showed that a great deal of the o-ring on the aft field joint vaporized immediately upon ignition, hence the smoke seen right after liftoff. The program I watched implied that residue from the combustion of the solid fuel sealed the breach, allowing the flight to continue, seemingly as normal. But the stresses of Max Q degraded the "pseudo-seal" and allowed the gases to leak out, thus the flame seen in the launch video.

Did anyone see this program, it was called "Challenger: the Untold Story", I believe. Has anyone else heard this explanation for the SRB surviving to 73 seconds?
I do not know what I may appear to the world; but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.

Newton

Offline Jim

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Re: Challenger STS-51L
« Reply #86 on: 03/23/2006 01:42 am »
That is the standard explanation for the breech lasting 73 seconds, but it was actually a wind shear it passed thru

Offline Thomas ESA

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Re: Challenger STS-51L
« Reply #87 on: 03/23/2006 10:18 am »
It was the strongest wind shere ever experienced by a Shuttle too. A terrible coincidence that would be suffered during a launch that simply didn't want it.

Offline Hotol

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Re: Challenger STS-51L
« Reply #88 on: 03/23/2006 12:54 pm »
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TheMadCap - 22/3/2006  7:02 PM


Did anyone see this program, it was called "Challenger: the Untold Story", I believe. Has anyone else heard this explanation for the SRB surviving to 73 seconds?

I think it was called something different on UK TV, but we saw that documentary and it was very well produced.

Online Chris Bergin

Re: Challenger STS-51L
« Reply #89 on: 03/23/2006 04:13 pm »
Quote
Hotol - 23/3/2006  1:54 PM

Quote
TheMadCap - 22/3/2006  7:02 PM


Did anyone see this program, it was called "Challenger: the Untold Story", I believe. Has anyone else heard this explanation for the SRB surviving to 73 seconds?

I think it was called something different on UK TV, but we saw that documentary and it was very well produced.

It was this one:

http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=1335&start=1
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Offline NASA_Twix_JSC

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Re: Challenger STS-51L
« Reply #90 on: 03/25/2006 03:12 am »
Well the upturn in interest was understandable with the 20th anniversary. I hope it becomes a memorial to the crew, rather than a form of TV fascination with disaster. Thankfully these documentaries were respectfully produced.

Offline zappafrank

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Re: Challenger STS-51L
« Reply #91 on: 03/25/2006 03:23 am »
I'm reading Mike Mullane's book Riding Rockets, and he goes into some detail about Challenger that I've never really read before, its sad, and makes you pretty angry.

Mike flew with Judy Resnik on their first flight, and he later found out that one had some pretty serious SRB burn through as well, yet the astronauts were kept in the dark, and culture was autocratic with John Young heading up the Astronaut corp that no one would ever raise a concern or they thought they would be booted from the program.

Offline zappafrank

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Re: Challenger STS-51L
« Reply #92 on: 03/25/2006 03:33 am »
When Challenger was lost, I was at college, returned home, knowing there was a launch, and caught it as the camera was showing the explosion, but there was no explanation.

I remember thinking that the ship had to be intact and would do an abort landing, and I was looking for the craft.  Of course realizing, but not wanting to that the aerodynamics forced the breakup.


When Columbia was lost, I was in Mexico City, I had followed this mission closely, as I had worked with Rick Husband's brother, who is an airline pilot, and I had talked with him several times on the phone.  I missed when Rick visited our hangar, he met with lots of people and distributed lots of paraphenalia, and I thought his brother was a hell of a good guy.  So, I knew that it would be returning, and I got up early, but it was still an orbit or two to go, so I went to the Pyramids at Teotechuan and climbed them and all that.  I got back, and was walking in the Zocalo and they had newspapers out with the picture of the re-entry, I found that to be rather odd, and only glanced at it, not realizing what it meant.  I got back to the hotel and turned on CNN and watched in horror about what had happened.

I don't want this to happen again, I will sweat bullets for the remaining 18 or so missions.  I want a simple system to get men into space, lets spend the dough once we are up there and get the private market involved.

Offline zappafrank

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Re: Challenger STS-51L
« Reply #93 on: 03/25/2006 03:43 am »
As for the stories about the inflight recorder, I don't believe it, Mullane doesn't believe it.  He noted that they lost all electrical power on breakup, all the helmet mic's went dead, and all the astronauts kept their helmets on with the screen drawn (they do that to stay alive, using their emergency air packs (air, not oxygen).  Even with a recorder going somewhere (would have to be battery pack), you couldn't hear them through their helmets.

Yes, they were alive, they did survive, either Judy or El Onizuka turned on Scobee's air, and Mike Smith activated some of the switches (spring loaded, covered switches that could not have been activated due to the explosion).  Mike and Dick tried to gain control for an abort landing, but they had zero power and they most likely realized that pretty quickly.

Now, could a few of them survived had the ejection system that was on STS 1-4 been on Challenger?  Maybe, but its a good sight better than falling for two and half minutes and impacting the ocean.

Offline Jim

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Re: Challenger STS-51L
« Reply #94 on: 03/25/2006 05:13 am »
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zappafrank - 24/3/2006  10:43 PM Now, could a few of them survived had the ejection system that was on STS 1-4 been on Challenger?  Maybe, but its a good sight better than falling for two and half minutes and impacting the ocean.

Doubt they could have activated them

Offline UK Shuttle Clan

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Re: Challenger STS-51L
« Reply #95 on: 03/25/2006 10:32 am »
I really want to think along those lines, but the guy posting the info on the post-breakup data is, with respect, in a better position to know than Mike Mullane. But it doesn't bare too much thinking about.

Offline Ben E

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Re: Challenger STS-51L
« Reply #96 on: 03/25/2006 07:13 pm »
I think it just shows that, no matter how 'safe' the 'safety' upgrades may be, a fairly "inconsequential" quirk or effect or accident can have the most profound consequences. Who'd have thought Challenger would encounter that wind shear? Who'd have thought that piece of foam would hit Columbia's wing in the very place (RCC Panel 8/9 interface) where re-entry temperatures were the fiercest?

I've just been poring over an interview with Don Lind and he says that the STS-51B boosters suffered serious blow-by, too. Think STS-51C's ascent was even hairier, possibly seconds away from disaster, if you believe Roger Boisjoly.

Offline Jamie Young

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Re: Challenger STS-51L
« Reply #97 on: 03/25/2006 08:41 pm »
Would Challenger have survived to SRB sep without the wind shear?

Offline Ben E

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Re: Challenger STS-51L
« Reply #98 on: 03/25/2006 09:27 pm »
We'll never know.

Offline TheMadCap

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Re: Challenger STS-51L
« Reply #99 on: 03/26/2006 05:02 pm »
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Jamie Young - 25/3/2006  3:41 PM

Would Challenger have survived to SRB sep without the wind shear?


Truly, we will never know for sure. IMHO, I think she would have made it. But of course, that would have given both companies managements even more ammunition to dismiss the engineers’ fears. A disaster was inevitable; I think it was just a question of time...
I do not know what I may appear to the world; but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.

Newton

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