Author Topic: Challenger STS-51L  (Read 166936 times)

Offline Jim

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Re: Challenger STS-51L
« Reply #160 on: 01/26/2014 10:43 am »

Also, is the recording of the mission control ground loops available anywhere?

no

Offline Jim

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Re: Challenger STS-51L
« Reply #161 on: 01/26/2014 10:45 am »
  To me it seems the sound starts as soon as the bottom of the LH2 tank fails and then gets louder when the flash is seen between the ET and the orbiter.

Because interference from all the gases

Offline brad2007a

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Re: Challenger STS-51L
« Reply #162 on: 01/26/2014 06:21 pm »

Also, is the recording of the mission control ground loops available anywhere?

no

Actually, if by "mission control ground loops" he means either the Flight Director's loop, or the PAO loop, they are available on YouTube (just search under "Challenger"). If he actually meant to say the "orbiter voice recordings", then the answer is no, of course.
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Offline spacecane

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Re: Challenger STS-51L
« Reply #163 on: 01/26/2014 08:09 pm »

Also, is the recording of the mission control ground loops available anywhere?

no

Actually, if by "mission control ground loops" he means either the Flight Director's loop, or the PAO loop, they are available on YouTube (just search under "Challenger"). If he actually meant to say the "orbiter voice recordings", then the answer is no, of course.

I meant the Flight Director's loop or similar from mission control.  I was just curious to hear how the controllers handled the recognition of the event.  I'd never want to hear the orbiter voice recordings.  The only thing I've ever been curious about is to know what video frame matches the "uh-oh" in the transcript.

Offline brad2007a

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Re: Challenger STS-51L
« Reply #164 on: 01/27/2014 08:48 pm »

Also, is the recording of the mission control ground loops available anywhere?

no

Actually, if by "mission control ground loops" he means either the Flight Director's loop, or the PAO loop, they are available on YouTube (just search under "Challenger"). If he actually meant to say the "orbiter voice recordings", then the answer is no, of course.

I meant the Flight Director's loop or similar from mission control.  I was just curious to hear how the controllers handled the recognition of the event.  I'd never want to hear the orbiter voice recordings.  The only thing I've ever been curious about is to know what video frame matches the "uh-oh" in the transcript.

Oh. Then yes, they are available to be heard - check on YouTube or, if you can get a hold of a copy, the Spacecraft Films "Challenger" DVD set.
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Offline spacecane

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Re: Challenger STS-51L
« Reply #165 on: 01/29/2014 01:18 pm »
To start this question, I don't believe that the RCS was used during ascent.  My question is theoretical.

IF a scenario such as what happened was envisioned as a possibility, could the RCS have been used to keep the orbiter pointing into the slipstream during the stack breakup (assuming an out of control SRB didn't crash into it)?  Could doing this have allowed the orbiter to stay intact and allowed the crew to perform a controlled ditching and had a chance to survive?

Offline Jim

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Re: Challenger STS-51L
« Reply #166 on: 01/29/2014 01:27 pm »

IF a scenario such as what happened was envisioned as a possibility, could the RCS have been used to keep the orbiter pointing into the slipstream during the stack breakup (assuming an out of control SRB didn't crash into it)?  Could doing this have allowed the orbiter to stay intact and allowed the crew to perform a controlled ditching and had a chance to survive?

No, forces were too great.

Offline edkyle99

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Re: Challenger STS-51L
« Reply #167 on: 01/29/2014 03:13 pm »
Re: the crew recordings.  For our younger readers, who might run across some fantastic, false claims on the World Wide Web, a bit of authoritative background is available here:
http://www.nytimes.com/1986/07/29/science/challenger-crew-knew-of-problem-data-now-suggest.html
and here:
http://history.nasa.gov/transcript.html

 - Ed Kyle
« Last Edit: 01/29/2014 03:17 pm by edkyle99 »

Offline Ronpur50

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Re: Challenger STS-51L
« Reply #168 on: 01/30/2014 04:09 pm »
While watching some of the memorial service on my DVDs yesterday, I saw Dick Scobee's son and wondered what ever happened to him.   Although time has seemed to stand still when I watch those images, it has moved on.  He is now Brigadier General Richard Scobee.  Commander Scobee would be 75 this year.  Wow.

Offline Hoppytje

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Re: Challenger STS-51L
« Reply #169 on: 01/31/2014 09:19 am »
Something new I read on the Wikipedia page of Mike Smith:
http://en.wikipedia.org/wiki/Michael_J._Smith_(astronaut)

" It has been claimed that his last words were, "Uh,oh". This is a false claim, based on a confused hearing of an in-studio analyst uttering these words at the time of explosion."

That's new to me. I always thought that "uh, oh", were his last words on the voice recorder.
« Last Edit: 01/31/2014 09:20 am by Hoppytje »

Offline spacecane

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Re: Challenger STS-51L
« Reply #170 on: 01/31/2014 02:28 pm »
Something new I read on the Wikipedia page of Mike Smith:
http://en.wikipedia.org/wiki/Michael_J._Smith_(astronaut)

" It has been claimed that his last words were, "Uh,oh". This is a false claim, based on a confused hearing of an in-studio analyst uttering these words at the time of explosion."

That's new to me. I always thought that "uh, oh", were his last words on the voice recorder.

That Wikipedia entry makes absolutely no sense.  The "uh oh" was part of the official transcript.  First of all, when doing audio analysis, they aren't watching the video.  Second, it's not like they listen once and write a transcript.  They listen over and over and do enhancements to determine what was said.

Also, somebody on the forum once posted that they were involved and actually heard the recording.  If I remember they described it as being not so calm as the transcript makes it sound.  Somebody should correct Wikipedia.

Offline Thorny

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Re: Challenger STS-51L
« Reply #171 on: 01/31/2014 02:35 pm »
The "Uh oh" comment as the last words on the Challenger recording is also supported in the new book "Wheels Stop" in a passage where Rick Hauck (I think) admonished one of his crew for saying 'uh oh' during training, telling him to never utter the phrase again.

Offline eeergo

Re: Challenger STS-51L
« Reply #172 on: 02/26/2014 07:23 am »
Reading through the "what-if" scenarios in this thread and other references, I came up with a slightly different thought experiment that I haven't seen analyzed before.

Suppose the propellant "pseudo-seal" in the SRB joint rupture hadn't formed at all at ignition, or just was too weak to be sustained for the 73 seconds it lasted in reality. From the accident report, it took around 15 seconds from the first flame coming out of the damaged SRB to total ET failure. If the flame had started at ignition, and assuming the plume behavior wasn't too affected by the lower speeds, that would put the ET failure right around the middle of the roll maneuver. Of course, one can imagine a seal that lasted a few seconds but failed soon after. The point is, what would have happened if the stack hadn't blown up in the pad, but the ET failed before it reached high speeds?

It has been argued before that an RTLS abort wouldn't have been possible in any case before SRB jettison, since otherwise they would have impinged on the orbiter/ET causing extensive damage, due to the jettisoning event making them diverge from the stack, which under full power would direct the exhaust directly on it. Or the orbiter would have crashed onto the ET, or both.

However, if they were not jettisoned but *released* in a similar event to the ET failure that happened in 51L, it appears they would swivel forward, converging towards one another and sending the exhaust outwards. Of course, the ET would already not be there for the orbiter to crash into. This would leave the orbiter to "just" deal with the effects of the hydrogen-oxygen detonation, assuming the SRBs managed to rocket out of there without hitting anything else, and assuming the MPS turbopumps would have enough time to stop without causing too much damage to the orbiter's aft (plausible?). In this early failure scenario, lacking the dispersive forces that it encountered at T+75s, and having more propellant left to burn, the detonation would probably have affected the orbiter more severely, but I don't know if this has been studied.

Then, if the detonation was survivable for the orbiter to keep certain maneuverability, it would emerge at around 2500 feet and a speed of 220mph. Would the aerodynamic environment in those conditions prevent breakup? If so, would this situation make it concievable, with luck on their side, to give some margin for a controlled glide to land somewhere in the Cape or ditch non-destructively into the ocean?

Of course, what happened happened, and may those brave souls rest in peace. For better or worse though, accidents like these make you want to know all their technical intricacies.
-DaviD-

Offline spacecane

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Re: Challenger STS-51L
« Reply #173 on: 02/27/2014 11:48 am »
Although I'm not an expert, I don't think there is any chance that the Orbiter would have had the aerodynamic authority to maneuver from vertical to horizontal at low speed.  I'm not sure a fighter jet could take off, climb vertically, shut off the engine at 2500 feet and make a horizontal landing.

The only way I can see that there may have been a different outcome for the crew is for something to have happened very close to the ground so that the only issues to deal with were the fire and SRB exhaust and self destruct and not the impact force of the crash.

Offline eeergo

Re: Challenger STS-51L
« Reply #174 on: 02/28/2014 01:14 am »
Although I'm not an expert, I don't think there is any chance that the Orbiter would have had the aerodynamic authority to maneuver from vertical to horizontal at low speed.  I'm not sure a fighter jet could take off, climb vertically, shut off the engine at 2500 feet and make a horizontal landing.

The only way I can see that there may have been a different outcome for the crew is for something to have happened very close to the ground so that the only issues to deal with were the fire and SRB exhaust and self destruct and not the impact force of the crash.

Residual thrust from the SSMEs should push the tail of the orbiter forward, pitching the nose down. Whether that force could be overcome by the ET deflagration (although most of its contents were pouring down, rather than radially), or if there were any conditions under which it wouldn't lead to an uncontrollable pitch or other non-recoverable situations, is something I don't have a clue about, but probably someone in these forums has a good idea of what could be expectable.

The fighter jet analogy is valuable (for someone who knows what fighter jets can or cannot do, which I don't), but one going straight up and shutting of the engine at 2500ft won't have the same speed as a shuttle lifting off (or the same inertia) - 220mph is about their nominal touchdown speed.

On the other hand, your scenario close to the ground may be survivable if the fire didn't affect the crew cabin too much: the crew cabin free-falling from a height close to the liftoff one would reach ~100km/h, higher speeds could be survivable being well strapped on. But an instantaneous failure is further from what really happened than an relatively small-scale O-ring failure since ignition, IMO.
« Last Edit: 02/28/2014 01:15 am by eeergo »
-DaviD-

Offline spacecane

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Re: Challenger STS-51L
« Reply #175 on: 02/28/2014 01:07 pm »


Residual thrust from the SSMEs should push the tail of the orbiter forward, pitching the nose down. Whether that force could be overcome by the ET deflagration (although most of its contents were pouring down, rather than radially), or if there were any conditions under which it wouldn't lead to an uncontrollable pitch or other non-recoverable situations, is something I don't have a clue about, but probably someone in these forums has a good idea of what could be expectable.

Since I believe the SSME thrust vector would be pointed towards the CG of the stack I think the residual thrust would flip the orbiter "backwards" into a spin of some sort.  My fighter analogy was more an aerodynamic control speculation.  I don't think there would be enough speed/altitude to be able to aerodynamically control the orbiter starting in a vertical orientation if an event happened at 2500 ft.

Offline MikeEndeavor23

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Re: Challenger STS-51L
« Reply #176 on: 01/04/2015 02:12 am »

    Interesting thread,

     I found a couple of interesting videos on youtube that might be of interest.  One is Dan Germany's testimony in front of the Space Science Tech Committee.



MikeEndeavor23

Offline MattMason

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Re: Challenger STS-51L
« Reply #177 on: 01/14/2015 02:10 pm »
This thread must remain ageless.

I was in my third year of college, coming home from class when I overhead a TV in the dorm. I ran into a stranger's room to see. A long-time space enthusiast and familiar with STS design, my first reaction cursed the External Tank, which I thought had ruptured.

Like many others both amateur and professional, the truths behind the STS design and its inherent flaws became reality as the Commission concluded and released their reports. While many changes were made, none of them helped Columbia's later demise, affirming the STS design to many (particularly it's Commission) as inherently experimental.

Getting back to capsule designs such as Orion, Dragon and CST-100 seemed instinctively backward to some, until you also take in the lessons of the past. Space is still a pioneering effort and escape to safety is just as important as getting there.

The thing that always gets me about the Challenger incident stems from my enjoyment of science fiction. As NASA finally readied OV-102 for the STS maiden flight, a decision was made not to refurbish OV-101, Enterprise, the first Orbiter used for the Approach and Landing Tests, deeming it too expensive to refit her.

As we know, OV-101 was originally to be named Constitution but, ostensibly through pressure from fans of the TV show, "Star Trek," President Ford authorized the renaming to the popular fictional starship, although others say it was named after the distinguished 19th Century schooner and World War II carrier.

With Enterprise left for ground tests, cannibalizing of her usable parts and later to be hauled off to a museum, a high-fidelity Orbiter aeroframe and structural test article, STA-099, was refitted to replace Enterprise, as OV-099, Challenger.

The pain and anguish on that day in 1986 might have become greatly magnified were it Enterprise that shattered in the skies that day.
"Why is the logo on the side of a rocket so important?"
"So you can find the pieces." -Jim, the Steely Eyed

Offline jacqmans

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Re: Challenger STS-51L
« Reply #178 on: 01/21/2016 07:58 am »
January 20, 2016

RELEASE J16-002

Maine Native and NASA Astronaut Honors Space Shuttle Challenger Astronauts

Maine’s newest NASA astronaut, Jessica Meir, will commemorate the 30th anniversary of the final space shuttle Challenger mission at events scheduled for Jan. 27-28, hosted at the Challenger Learning Center of Maine.

Selected in 2013 as part of the 21st astronaut class, Meir recently completed her astronaut candidate training and is now qualified for mission assignment. Meir is serving currently as a spacecraft communicator (CAPCOM) supporting the Mission Control Center in Houston, Texas, and crews onboard the International Space Station. Born and raised in Caribou, Maine, she earned a bachelor’s degree in biology from Brown University, a master’s in space studies from International Space University, and a doctorate in marine biology from Scripps Institution of Oceanography.

“I remember exactly where I was on that day 30 years ago, excitedly watching the launch countdown along with my third-grade classmates in Caribou, Maine,” Meir said.  “The tragic loss of the crew is something we will always remember and carry in our hearts. I know these astronauts would have been proud of the global network of centers created in their memory, dedicated to inspiring students through unique educational experiences.”

The Challenger Learning Center, located in Bangor, Maine, will host middle school students from across the state for a special presentation by Meir at the Collins Center for the Arts, Jan. 27. The student-only event will be followed by an after-school open house at the Challenger center, in collaboration with the Maine Science Festival. Members of the public are welcome to meet Meir and tour the center. Meir also will be the keynote speaker at a special reception for invited guests at the Challenger Center later that evening.

The morning of Jan. 28, local members of the media are invited to register for live interviews with Meir at the Challenger Center. Interested media may schedule an interview by contacting Susan Jonason, the center’s executive director, by email at [email protected].

“The families of the Challenger crew created the Challenger Centers to continue their education mission through space-themed learning and role-playing strategies to help bring students’ classroom studies to life and cultivate skills needed for future success”, Jonason said. “We feel very fortunate to have one of these wonderful centers right here in Bangor.”

For event details and more on the Challenger Learning Center of Maine, visit:

https://www.astronaut.org/

For more information on Meir, visit:

http://www.jsc.nasa.gov/Bios/htmlbios/meir-ju.pdf

Follow her on Twitter: @Astro_Jessica

To learn more about NASA’s education resources, visit:

http://www.nasa.gov/offices/education/programs/national/ercn/home/
Jacques :-)

Offline kking

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Re: Challenger STS-51L
« Reply #179 on: 01/22/2016 03:11 pm »
I just found a live coverage of 51L launch.




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