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Author
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Topic: STS-51L: Myths about the Challenger disaster
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FFrench
Member Posts: 3209
From: San Diego
Registered: Feb 2002
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posted 01-26-2006 07:42 PM
  
An interesting article by Jim Oberg on Challenger. Twenty years ago, millions of television viewers were horrified to witness the live broadcast of the space shuttle Challenger exploding 73 seconds into flight, ending the lives of the seven astronauts on board. And they were equally horrified to learn in the aftermath of the disaster that the faulty design had been chosen by NASA to satisfy powerful politicians who had demanded the mission be launched, even under unsafe conditions. Meanwhile, a major factor in the disaster was that NASA had been ordered to use a weaker sealant for environmental reasons. Finally, NASA consoled itself and the nation with the realization that all frontiers are dangerous and to a certain extent, such a disaster should be accepted as inevitable.At least, that seems to be how many people remember it, in whole or in part. That’s how the story of the Challenger is often retold, in oral tradition and broadcast news, in public speeches and in private conversations and all around the Internet. But spaceflight historians believe that each element of the opening paragraph is factually untrue or at best extremely dubious. They are myths, undeserving of popular belief and unworthy of being repeated at every anniversary of the disaster. I'm pleased he repeats the point that Challenger did not "explode" - an error that is printed in many otherwise flawless accounts - but broke apart due to wind shear. It's important to remember that the shuttle itself has never failed - it's the results of the booster tank and SRBs on the shuttle during launch that have led to its loss on two occasions. |
Hawkman
Member Posts: 400
From: Union, New Jersey
Registered: Jan 2001
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posted 01-27-2006 02:55 PM
I read that article today. Mr. Oberg as usual does a fine job.I, too, was glad that he points out that the Challenger did not "explode." I'm amazed that there are press people who continue to put forth that view. |
Robert Pearlman
Editor Posts: 46476
From: Houston, TX
Registered: Nov 1999
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posted 01-27-2006 03:03 PM
Mike Mullane devotes a chapter of his new book "Riding Rockets" to sharing the astronaut's view (at the time) of what happened to the Challenger crew. It's difficult to read, especially if you haven't heard the fine details before. The media most often cites the PEAPs (emergency oxygen packs) as evidence of at least some of the crew's awareness during their 2.5 minute fall to the ocean. Mullane writes about other conditions within the recovered cockpit, some I have not heard or read about anywhere else. |
moorouge
Member Posts: 2484
From: U.K.
Registered: Jul 2009
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posted 09-16-2009 11:45 AM
Apologies for coming late to this thread as I've only just found it.I had a long talk with Bob Overmyer about Challenger. He said that the PEAPs were able to be shaken free from their mountings on the back of the seats by a sudden jolt and that once released the air mix flowed automatically. This would seem to contradict what Mullane says in his book "Riding Rockets." So, who does one believe? The fact that the PEAPs were depleted does not necessarily prove the crew survived the break-up if there was an automatic release of their air supply. Which leads me to a hypothetical question. As I understand it, an abnormal wind shear factor played a part in the accident. If this hadn't been present, would the crew have had time to recognise the anomaly in the thrust from the SRB and jettison them to make a return to launch site abort? Finally, I seem to remember reading in the early days of the shuttle that a NASA risk assessment was expecting a "critical one" failure involving possible crew loss every 25 launches. Yes, they may have become complacent, but the fact that they have done far, far better than this surely is to their credit as well. |
OV-105
Member Posts: 858
From: Ridgecrest, CA
Registered: Sep 2000
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posted 09-16-2009 12:29 PM
The PEAPs could have been active but even if they were pressure or demand system when a person takes a breath more air would go into the helmet. One other thing two that were found and used were the commander Dick Scobee's and pilot Mike Smith's since the were still mounted to the back of each seat.The shuttle crew has no way to really watch the pressure of the SRBs during launch. The pressure difference was not too great between the two SRBs that it would have alarmed anyone. It would be a crap shoot to do a fast separation from the SRBs. That is the big draw back of the SRBs, once they are lit you have them until the are spent. The RTLS Abort is going to be hard to do even if it is just with a SSME if it goes down. I think the risk number you heard is what came out after the loss of Challenger. |
ilbasso
Member Posts: 1527
From: Greensboro, NC USA
Registered: Feb 2006
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posted 09-16-2009 12:32 PM
You can't jettison the SRBs, even if you know there's a potential disaster building. None of the abort scenarios occur until after the SRBs are separated. Once they're ignited, you have to let them burn out. If you cut them loose, they'd fly right past the Shuttle and cook everyone in the crew compartment - not to mention super-heating the ET fuel tanks and probably causing an explosion. |
Jay Chladek
Member Posts: 2272
From: Bellevue, NE, USA
Registered: Aug 2007
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posted 09-16-2009 02:02 PM
The main thing about the PEAPs as I've understood it wasn't so much that the air bottles were depleted, but rather that on at least a pair of them the switch was physically moved from off to on (which MS Judy Resnik probably did on instinct to stabilize the commander's and pilot's O2 flow). I imagine once they hit the ocean, the contents more then likely would have bled out, so I find it unlikely there was any pressure left to read once they had been recovered.I've felt after gathering more information about Challenger in recent years that if the crew was alive during the plunge that they probably weren't conscious, given the breakup occurred at about 40,000 feet with the cabin going uphill for a bit before it began its descent. Given the extreme nature of the breakup, an intact crew cabin doesn't mean it can hold pressure, given that air lines would have ruptured. Even with Columbia, according to the crew survivability report, micro fractures in the floor below the mid-deck would have depressurized the cabin quick. Loss of consciousness would have been within 10 seconds as Payne Stewart's Lear Jet crash showed (depressurization was at over 40,000 feet in that case). The PEAPs don't deliver pressurized O2 as they aren't intended to be used in loss of pressure situations. As for the wind shear, that was the straw that broke the camel's back with the SRBs. The o-rings sealed okay after the initial failure at liftoff until the wind shear hit them and that is what opened up the leak again, and it thus blowtorched the aft SRB strut and the rest is history. Of course, post mission analysis would have revealed the serious primary and secondary O-ring leak, meaning the problem would have been a ticking time bomb for another mission. I am glad Jim mentioned the vehicle didn't explode as the LOX and LHX mixing didn't produce a concussive force as it were (it would be a combustion rather then an explosion) and it was the slipstream that ripped the orbiter apart. I have heard speculation that the orbiter might have been hit on the right wing by the pivoting SRB, but I am not sure about that. So much crap was coming out of that fireball, who knows for certain what caused that wing to part company and if it was before or during the rest of the vehicle breakup? |
Tykeanaut
Member Posts: 2221
From: Worcestershire, England, UK.
Registered: Apr 2008
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posted 03-03-2015 06:31 AM
If the flame retardent foam had still been in use on the External Tank would that have helped avert the huge explosion? |
Jim Behling
Member Posts: 1641
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 03-03-2015 07:05 AM
The foam doesn't burn as it is. The flame from the SRB would have eroded any kind of foam and melt the metal tank's skin. |
dabolton
Member Posts: 419
From: Seneca, IL, US
Registered: Jan 2009
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posted 03-03-2015 10:30 PM
How confident are they that if the SRBs had been cut loose they would have scorched the cockpit? They are both below and to right/left of the cockpit centerline. Why couldn't an abort scenario have steered the boosters out and away as they accelerated forward. It would also depend on how quickly the SRBs accelerate away as to how much exposure the orbiter would have had. |
Cozmosis22
Member Posts: 1085
From: Texas * Earth
Registered: Apr 2011
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posted 12-07-2015 03:39 PM
By 1986, space shuttle liftoffs were apparently becoming "routine" and thus not worthy of live coverage.For the record, CNN was the only network that broadcast the 51-L launch live. NBC was first to break into its regularly scheduled programming at 11:42 a.m.; followed by ABC at 11:43 and then CBS at 11:45.  |
Jim Behling
Member Posts: 1641
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 12-07-2015 08:00 PM
quote:
Originally posted by dabolton:
Why couldn't an abort scenario have steered the boosters out and away as they accelerated forward.
Once cut loose, the SRBs are no longer under control. And it would be impossible to cut them loose, while under thrust. The forward attachment requires the SRB have less thrust than the SSMEs for jettison. |
Kestrel72
Member Posts: 11
From: Charlotte, NC
Registered: Apr 2015
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posted 12-10-2015 11:51 AM
What about cutting loose from the ET, with the SRBs still attached? Could Challenger have separated from the ET and SRBs and maneuver away to a safe distance or would the aerodynamic stresses still have ripped the shuttle apart? I've always wondered if someone had seen the TV feed showing the burn-through on the right SRB and warned the crew — is there anything the crew could have done? |
Jim Behling
Member Posts: 1641
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 12-10-2015 02:06 PM
quote:
Originally posted by Kestrel72:
What about cutting loose from the ET, with the SRBs still attached?
Fast Sep as it was called was not really viable either. The aft attach points were ball joints and would have hung up. |
DeepSea
Member Posts: 69
From:
Registered: Jun 2014
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posted 12-11-2015 10:52 AM
quote:
Originally posted by Robert Pearlman:
Mullane writes about other conditions within the recovered cockpit, some I have not heard or read about anywhere else.
If you are referring to switches for the orbiter's electrical systems being moved out of their nominal launch positions, I have heard this corroborated by two other individuals who were part of the crew compartment investigation. Grim. quote:
Originally posted by Jim Behling:
Fast Sep as it was called was not really viable either. The aft attach points were ball joints and would have hung up.
Interesting to read, Jim. Thanks. Do you have any idea why the Fast Sep procedure was even "a thing" in the first place if it was no use in the real world? |
Glint
Member Posts: 1056
From: New Windsor, Maryland USA
Registered: Jan 2004
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posted 12-11-2015 12:02 PM
quote:
Originally posted by Cozmosis22:
...For the record, CNN was the only network that broadcast the 51-L launch live.
In other words, none of the "big 3" non-cable networks broadcast it. But the launch was broadcast live on non-cable channels. Not everyone had cable or lived in locales where cable was even available. So the CNN effort was only of benefit for those that had cable TV in 1986. An independent station in the Washington D.C. area carried the NASA channel feed during the launch and thus broadcast it live and free, with no need for cable. I had to work that day but had asked a friend to monitor the station and make a VHS recording of the launch. I suspect there were other independent stations throughout the country that did the same thing. |
onesmallstep
Member Posts: 1327
From: Staten Island, New York USA
Registered: Nov 2007
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posted 12-11-2015 02:15 PM
I remember vividly the Challenger accident, but not visually. I was working in downtown NYC, and the radio was on to a 24-hour news program. The program cut to a bulletin from the cape, and said that a "rescue and recovery" operation was in progress. But I, as a long-time follower of the space program, knew the crew was lost. It was made more dramatic by using my mind's eye as to what had happened high in the skies over Florida without seeing a visual image or video. |
Cozmosis22
Member Posts: 1085
From: Texas * Earth
Registered: Apr 2011
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posted 12-11-2015 07:54 PM
quote:
Originally posted by Glint:
An independent station in the Washington D.C. area carried the NASA channel feed during the launch and thus broadcast it live and free, with no need for cable.
From the USA TODAY article shown above, "Only CNN, which has 24 hours to fill with news, still covers shuttle launches live."Apparently some "independent" stations carried the liftoff in places like DC and some schools had access to the KSC television feed. Don't think there was a NASA Channel at that time. At the Cape the local TV channels, including the Big 3 network affiliates out of Orlando may have broadcasted to their Florida audiences, but it was not generally seen live nationwide that tragic Tuesday morning. |
Ronpur
Member Posts: 1246
From: Brandon, Fl
Registered: May 2012
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posted 12-11-2015 09:41 PM
I think they called it "NASA Direct" or at least they did in 1988 for the RTF when it was carried on our cable. |
Jim Behling
Member Posts: 1641
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 12-13-2015 12:09 PM
quote:
Originally posted by Ronpur:
I think they called it "NASA Direct"
It was NASA Select.
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Ronpur
Member Posts: 1246
From: Brandon, Fl
Registered: May 2012
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posted 12-13-2015 06:10 PM
Of course it was! Well, at least I remembered it rhymed with Select.
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Glint
Member Posts: 1056
From: New Windsor, Maryland USA
Registered: Jan 2004
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posted 12-14-2015 11:45 AM
Speaking of seeing the launch live, I had an office mate three years ago that saw it in person. He grew up in Orlando and after his kindergarten class saw Challenger clearing the tower on television they were quickly marched outside to see it ascending. It was the fascinating recollection of a 5 year-old kid who basically didn't know at the time what was going on or why it was such a big deal. He remembered seeing the cloud and having a sense that something bad happened because of the reactions of adults. He didn't have time to see much because they were quickly hustled back inside the school. |
psloss
Member Posts: 32
From:
Registered: Jun 2011
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posted 12-14-2015 05:02 PM
Re: NASA Select, anyone with big C-band dishes could get it, but their big customer would have been the TV networks. CNN was essentially rebroadcasting that transmission with Tom Mintier's commentary over the top of the standard audio that was provided for all Shuttle missions. (Well, for all the non-military missions, anyway.)Thanks for the banter because it was a good excuse to go to YouTube, search on "NASA Select" to see what might be there today. Today I found someone who had posted about an hour of the 51-G broadcast (edited) of the terminal count, launch/insertion, and post-launch on 17 June 1985. That YouTube user also posted a clip of one of the public film/video analysis presentations. This was apparently to the House oversight committee or subcommittee, but it looks similar to one made at a Rogers Commission public hearing in the same time period; it notes something that seems to get less "play" than the lower strut failure and its consequences up in the intertank area -- namely, the failure of the ET LH2 tank.
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mach3valkyrie
Member Posts: 729
From: Albany, Oregon
Registered: Jul 2006
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posted 12-14-2015 06:28 PM
I purchased a 12 foot aluminum mesh dish in October 1985 and watched NASA Select a lot after that. I had it on during Challenger and was recording on my Betamax VCR. I still have a lot of beta stuff and a machine to play them on. Friends had some smaller fiberglass dishes that had a lot of snowy pictures onscreen, but I was able to watch NASA Select during most of 1985. |
Headshot
Member Posts: 1004
From: Vancouver, WA, USA
Registered: Feb 2012
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posted 12-15-2015 05:53 PM
The House Committee on Science and Technology conducted their own Investigation of the Challenger Accident in 1986. Two Volumes of Hearings (one for those conducted in June and another for those conducted in July) were published and a formal Report was issued in October 1986. |
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