Author Topic: Challenger STS-51L  (Read 111204 times)

Offline joema

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Re: Challenger STS-51L
« Reply #180 on: 01/24/2016 09:46 PM »
National Geographic Channel will be showing a documentary this week about STS-51L. It is titled "Challenger Disaster: Lost Tapes". It apparently uses cinema verite techniques (no narrator, no interviews, no recreations) to factually explain the event using previously unseen archival footage.

http://www.natgeotv.com.au/tv/challenger-disaster-lost-tapes/

http://natgeotv.com/uk/challenger-disaster-lost-tapes/about

Link to trailer: http://tinyurl.com/zgkc7cx

Offline Tony Trout

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Re: Challenger STS-51L
« Reply #181 on: 01/26/2016 05:36 PM »
National Geographic Channel will be showing a documentary this week about STS-51L. It is titled "Challenger Disaster: Lost Tapes". It apparently uses cinema verite techniques (no narrator, no interviews, no recreations) to factually explain the event using previously unseen archival footage.

http://www.natgeotv.com.au/tv/challenger-disaster-lost-tapes/

http://natgeotv.com/uk/challenger-disaster-lost-tapes/about

Link to trailer: http://tinyurl.com/zgkc7cx


I saw that last night.  Wasn't really impressed with it.  It just basically showed the time leading up to the launch,the pick of Christa as the first teacher and tried to explain why Challenger exploded - which was because of two factors:  The temperature at launch and the failure of the O-Rings to do their job and seal the insides of the SRBs like they were supposed to. 


Where was everyone when it happened? I was just a little kid, but I remember the newsflash as it interupted a kids show I was watching.


I was home from school for a teacher workday and watched the entire thing.  When the voice came over the loudspeakers at KSC that said, "Obviously, a major malfunction", those words really made me angry because they apparently couldn't tell that the Challenger had blown up at that point.  From past Shuttle missions, they should have known that the huge plume of smoke wasn't just SRBs separating.  It's ironic but as soon as I saw that one ball of fire ignite from the right SRB, I knew there was gonna be a horrific accident.

The late Roger Boisjoly, formerly with Morton-Thiokol, knew that the Challenger shouldn't have launched in that cold air because the O-Rings wouldn't seal properly. 

Were NASA that launch-trigger happy that they didn't care about the safety of the six astronauts and one civilian (Christa McAuliffe) on board the shuttle that day?   >:(  NASA apparently thought, "We've done it before with no problems.  I don't see a problem with launching at these temperatures?"  Boy, were they wrong......:(

I'm just honestly wondering.....

« Last Edit: 01/26/2016 05:39 PM by Tony Trout »

Offline LaunchedIn68

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Re: Challenger STS-51L
« Reply #182 on: 01/26/2016 11:57 PM »


[/quote]
When the voice came over the loudspeakers at KSC that said, "Obviously, a major malfunction", those words really made me angry because they apparently couldn't tell that the Challenger had blown up at that point.  From past Shuttle missions, they should have known that the huge plume of smoke wasn't just SRBs separating. [/quote]

Well no, they couldn't tell that it broke up because they're not looking at the TV first off.  Their eyes are glued to their screens monitoring data, and only knew SOMETHING was wrong when they lost all downlink.  In the video of Rick Hauck at CAPCOM, you see him glance at the TV that was there with an incredulous look on his face.  He's stated that he was looking at his data on the screen, and only because a flash of light on the TV next to him, in his peripheral vision caused him to look over and see the plume.  No one that day in Mission Control expected an explosion.  An engine loss resulting in an RTLS/TAO sure, multitude of alarms or systems going offline yes, any number of scenarios they simulated to react to.  Remember, they weren't privy to the conversation the night before between management and Thiokol.

"Obviously, a major malfunction" yes not the best choice of words but what DO you say at a time like that?

I personally liked the show.  The disaster has been covered and recovered so many times in documentaries and books etc..., that  I know the entire analysis inside and out.  But watching the video clips from those days, brought me back 30 years to that day when I came home as a high school senior, from a half day of school for taking an English midterm exam.  I thought it was well done and was a welcome change.  The details are covered elsewhere.  I would have liked some more on the other crewmembers though.
« Last Edit: 01/26/2016 11:58 PM by LaunchedIn68 »
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Offline joema

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Re: Challenger STS-51L
« Reply #183 on: 01/27/2016 02:58 PM »
...I saw that last night.  Wasn't really impressed with it.  It just basically showed the time leading up to the launch,the pick of Christa as the first teacher and tried to explain why Challenger exploded - which was because of two factors:  The temperature at launch and the failure of the O-Rings to do their job and seal the insides of the SRBs like they were supposed to....

The documentary was an archival cinema verite piece (no narration, no voiceover) which is a highly constrained format. It is considered more "pure" from a documentary standpoint. I agree it felt limited but that is the nature of this presentation style. Cinema verite expects viewers to simply accept what can be presented in that narrow style, rather than narration, graphics and interviews leading you by the hand to an editorial position.

I am surprised they did not include the available footage and crew dialog from the P3 Orion "Cast Glance" photographic plane which tracked the SRBs.

For anyone interested in deep technical and procedural aspects, by far the most detailed account of the disaster and history of the SRB program is "Truth, Lies, and O-Rings: Inside the Space Shuttle Challenger Disaster", by Allan J. McDonald.

McDonald discusses what happened and implications for engineering ethics in this interview:

While a different incident, the transcript of the Columbia Accident Investigation Board (CAIB) from 4-23-03 is very educational, in particular statements by Robert F. Thompson, the shuttle program manager from inception to first flight. It covers key shuttle development decisions, development costs, planned flight rate, etc (do right-click and save as): https://www.nasa.gov/columbia/caib/PDFS/VOL6/H08.PDF If problems opening this, use top-level link and select "H.8 April 23,2003 Houston,Texas" : https://www.nasa.gov/columbia/caib/html/VOL6.html

Offline Tony Trout

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Re: Challenger STS-51L
« Reply #184 on: 01/27/2016 06:02 PM »
.....at any point during the launch and flight of Challenger that anything was wrong?  Has it ever been published as to what the crew experienced when the accident happened? 

I know that sounds morbid and probably is.....but it's something I've always been curious about.
 


Offline Rocket Science

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Re: Challenger STS-51L
« Reply #185 on: 01/27/2016 06:23 PM »
.....at any point during the launch and flight of Challenger that anything was wrong?  Has it ever been published as to what the crew experienced when the accident happened? 

I know that sounds morbid and probably is.....but it's something I've always been curious about.

Difficult reading...
http://www.spacesafetymagazine.com/space-disasters/challenger-disaster/
http://spaceflightnow.com/challenger/timeline/

http://er.jsc.nasa.gov/seh/explode.html
http://www.spaceacts.com/howdied.htm

In case you don't know/remember Dr. Joe Kerwin:

http://www.jsc.nasa.gov/Bios/htmlbios/kerwin-jp.html
« Last Edit: 01/27/2016 06:49 PM by Rocket Science »
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Online woods170

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Re: Challenger STS-51L
« Reply #186 on: 01/27/2016 06:27 PM »
.....at any point during the launch and flight of Challenger that anything was wrong?  Has it ever been published as to what the crew experienced when the accident happened? 

I know that sounds morbid and probably is.....but it's something I've always been curious about.
 



I suggest you read the report of the Rogers commission:

http://history.nasa.gov/rogersrep/genindex.htm
or on this forum as pdf (in the first post): https://forum.nasaspaceflight.com/index.php?topic=8535.0

Offline hygoex

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Re: Challenger STS-51L
« Reply #187 on: 01/28/2016 12:12 AM »
Had the windshear not been present, would the accident possibly have been avoided?

Offline catdlr

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Re: Challenger STS-51L
« Reply #188 on: 01/28/2016 06:52 AM »
30 years later, Challenger widow tells her story

Article and video

https://www.yahoo.com/katiecouric/30-years-later-challenger-widow-tells-her-story-140818583.html

Quote
“I often say that we were tremendously excited, the whole bunch of us were tremendously excited that we were kind of on this major interstate highway moving toward the heavens,” says June Scobee Rodgers, remembering Jan. 28, 1986, the day her husband, Cmdr. Dick Scobee, boarded the Challenger space shuttle.

“And then this terrible, numbing accident happened,” she says. “And he just kept on going toward heaven. And he left me dangling at the edge of that highway.”
Tony De La Rosa

Offline Ronpur50

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Re: Challenger STS-51L
« Reply #189 on: 01/28/2016 11:34 AM »
30 years later, Challenger widow tells her story

Article and video

https://www.yahoo.com/katiecouric/30-years-later-challenger-widow-tells-her-story-140818583.html

Quote
“I often say that we were tremendously excited, the whole bunch of us were tremendously excited that we were kind of on this major interstate highway moving toward the heavens,” says June Scobee Rodgers, remembering Jan. 28, 1986, the day her husband, Cmdr. Dick Scobee, boarded the Challenger space shuttle.

“And then this terrible, numbing accident happened,” she says. “And he just kept on going toward heaven. And he left me dangling at the edge of that highway.”

I watched that, and it was a great tribute.  But I was struck by the realization when I see June Scobee Rodgers, that 30 years have indeed passed.  I always remember her in the video with President Reagon at Houston. 

Dick Scobee would have been 76.  They have stayed young in our minds, while the rest of us have gotten old.  I wish they had gotten old with us.
« Last Edit: 01/28/2016 11:54 AM by Ronpur50 »

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Re: Challenger STS-51L
« Reply #190 on: 01/28/2016 12:48 PM »
Chris Gebhardt's article to mark the 30th anniversary:
http://www.nasaspaceflight.com/2016/01/the-challenger-seven-remembered-51l/

Offline MattMason

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Re: Challenger STS-51L
« Reply #191 on: 01/28/2016 01:03 PM »
Had the windshear not been present, would the accident possibly have been avoided?

No.

At ignition of the SRBs, the O-ring joint of the key Solid Rocket Booster immediately failed, blowing hot gases through to begin the degradation of the rest of the seals. It temporarily sealed itself for a few seconds before it reopened and became a blowtorch that tore out the bottom of the External Tank. This is shown in both video and stills of a black puff of smoke at the affected area.

In any case, once the SRBs are ignited, there were no abort options for the launch vehicle until SRB separation. From my understanding, an Orbiter attempting to break from the ET while under SRB power would shatter its airframe just as Challenger did on ET detonation.
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Re: Challenger STS-51L
« Reply #192 on: 01/28/2016 02:05 PM »
Chris Gebhardt's article to mark the 30th anniversary:
http://www.nasaspaceflight.com/2016/01/the-challenger-seven-remembered-51l/

And that's getting a lot of deserved attention. BBC Radio having Chris on very shortly to talk about Challenger.
http://www.bbc.co.uk/radio/watchlive/5live

Offline Hog

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Re: Challenger STS-51L
« Reply #193 on: 01/28/2016 02:27 PM »
Had the windshear not been present, would the accident possibly have been avoided?

No.

At ignition of the SRBs, the O-ring joint of the key Solid Rocket Booster immediately failed, blowing hot gases through to begin the degradation of the rest of the seals. It temporarily sealed itself for a few seconds before it reopened and became a blowtorch that tore out the bottom of the External Tank. This is shown in both video and stills of a black puff of smoke at the affected area.

In any case, once the SRBs are ignited, there were no abort options for the launch vehicle until SRB separation. From my understanding, an Orbiter attempting to break from the ET while under SRB power would shatter its airframe just as Challenger did on ET detonation.
It's my understanding that the re sealed failure was broken loose during the largest windshear experienced during STS.  The first puffs of smoke occurred at T+ 0.6 seconds and occurred at the same frequency as residual "twang" motions until T+ 2.7 seconds 
The windshear was encountered at T+ 38 seconds  for approx. 27 seconds.
The plume from the leak was not noticed until T+ 58 seconds,
At T+60 the plume was well defined and was impinging upon the tank.
At T+ 64 the plume changed indicating the Hydrogen leaking
At T+66 seconds, the ET's indicated pressure dropped

That seal held for almost a minute.  Including the time where both the SSME's and the SRB's all throttle down and then throttle back up.  The SRB pressure was increasing from the Max Q throttledown from T+50 seconds through to breakup.
If that reseal did hold, chance are that no one would have known anything was wrong until the ascent film was viewed or until the SRBs were recovered and inspected.

I don't think that the phrase "if the windshear didn't occur, the outcome may have been different" can simply be discounted outright.  Of course that's my personal opinion, and of course we'll never know.

Highest respects to family and friends of all involved.
Paul

Offline MattMason

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Re: Challenger STS-51L
« Reply #194 on: 01/28/2016 02:32 PM »
Thanks, Hog. There was an earlier flight with a O-ring blowback that did reseal itself and stay resealed, right? Turns out 51-L wasn't as lucky. Thanks for the clarification.
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Offline MattMason

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Re: Challenger STS-51L
« Reply #195 on: 01/28/2016 03:28 PM »
My thoughts on the incident:

I was attending Indiana University in Bloomington, Indiana, coming back from a class. I overheard a news broadcast as I made my way through a dorm hallway. I knew of the flight, tracking its launch time (and earlier delays) but knew I'd be in class at the time of launch. I had made a silent remembrance of Aoollo 1's 19th anniversary of its accident, 19 years and a day before.

I was quite familiar with the STS components and never liked what I thought was one flimsy component: the external tank. On seeing the explosion, I spat out an expletive, thinking that the ET had popped.

Turns out I was half-right. The ET popped because of the SRB blowtorch that cut a hole in its bottom dome.

That sensation of NASA being able to do little wrong since Apollo 1 disappeared.

The mood of the students and faculty was somber and confused. I found myself explaining some space terminology to those unfamiliar. I would not feel the same sense of mourning, anger, and confusion until September 11, 2001.

The year 1986 kept going with tragedy both worldwide and personal. The Chernobyl accident occurred a few months later in April. And as I was packing up the last of my things from my dorm room in May, I got a call about my father's death.

So if I had to do things over again, we can just skip 1986, personally.

But, but skipping things, we'd never learn and fix mistakes that would've doomed another Orbiter. It would've just happened to some other nice folks.
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Offline hygoex

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Re: Challenger STS-51L
« Reply #196 on: 01/28/2016 07:07 PM »
In the TV movie Challenger which I just looked at again, during the break in the pre-launch meeting with Thiokol, Cecil Houston got a call from the Coast Guard saying the booster recovery ships were in a "full gale" and headed back to port.  Any truth to this? 
« Last Edit: 01/28/2016 07:07 PM by hygoex »

Offline ChrisGebhardt

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Re: Challenger STS-51L
« Reply #197 on: 01/28/2016 07:33 PM »
Thanks, Hog. There was an earlier flight with a O-ring blowback that did reseal itself and stay resealed, right?

Not quite. There were a couple of O-ring issues in the early phase of the program, but the one you're thinking of is STS-51C on the Shuttle Discovery.

Taken from one of our article in October 2015:

"During the 24 January 1985 launch of Shuttle Discovery on the STS-51C mission, ambient air temperature at the time of launch was just 53°F.

Post-flight recovery and inspection of the SRBs from STS-51C showed charring to the primary O-rings on both the left and right hand SRBs.

However, it was the burn path penetration through the primary O-ring on the center field joint of the right SRB from STS-51C, coupled with heavy charring on the secondary O-ring (indicating a near burn through event of the field joint), that provided a direct link to a mission one year and four days later."

Offline JayJay

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Re: Challenger STS-51L
« Reply #198 on: 02/01/2016 04:41 PM »
Hypothetical question here and I apologize if this has been answered but I've searched and cannot find an answer to this.  I know that the SRBs continued to fire until they were destroyed by the SRO.  It only just occurred to me, what if the burn through had occurred in a "safer" location (ie. away from the ET and shuttle), could the shuttle have made it to SRB SEP?  I know that the shuttle engine gimbals and SRB gimbals had already started reacting to the SRB thrust asymmetry, but at what point would they have not been able to keep control of the stack?

Offline Jim

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Re: Challenger STS-51L
« Reply #199 on: 02/01/2016 04:49 PM »
ET detonation.

Disintegration.  It did not blow up.  Once the propellants were released, there was a deflagration and not a detonation.  The ET came part from the hot gas impinging on it and the loads.

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