Author Topic: Challenger STS-51L  (Read 88765 times)

Offline Orbiter Obvious

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Re: Challenger STS-51L
« Reply #20 on: 12/06/2005 10:22 PM »
I wasn't born, but does anyone know if NASA will do something special for the 20th Anniversary next year?

Offline Avron

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Re: Challenger STS-51L
« Reply #21 on: 12/07/2005 04:36 AM »
I remember it well, was in my car listening to the radio.
Was always concerned that there was no way out for the crew, even if the problem was detected prior to the explosion.
I can remember looking at footage of the launch control center, and at the far side of the room was a TV, and on that TV was realtime footage of teh launch and the SRB plume that is clearly visable to anyone who was watching that TV, the rest of the world where watching the TV picture from another (or more standard view), now if someone had noted the plume from the SRB on the TV, there was no abort button to push.. and still is not..

Stolen from the Rogers report:  (what is most amazing is how the vehicle is trying to keep alive, a no win situation)


38:51.870  SSME 104% Command                   51.860  E41M2076D
   38:58.798  First evidence of flame on RH SRM   58.788  E207 Camera
   38:59.010  Reconstructed Max Q (720 psf)       59.000  BET
   38:59.272  Continuous well defined plume
                    on RH SRM                     59.262  E207 Camera
   38:59.763  Flame from RH SRM in +Z direction
              (seen from south side of vehicle)   59.753  E204 Camera
   39:00.014  SRM pressure divergence (RH vs. LH) 60.004  B47P2302
   39:00.248  First evidence of plume deflection,
                intermittent                      60.238  E207 Camera
   39:00.258  First evidence of SRB  plume
              attaching to ET ring frame          60.248  E203 Camera
   39:00.998  First evidence of plume deflection,
               continuous                         60.988  E207 Camera
   39:01.734  Peak roll rate response to wind     61.724  V90R5301C
   39:02.094  Peak TVC response to wind           62.084  B58H1150C
   39:02.414  Peak yaw response to wind           62.404  V90R5341C
   39:02.494  RH outboard elevon actuator hinge
               moment spike                       62.484  V58P0966C
   39:03.934  RH outboard elevon actuator delta
                pressure change                   63.924  V58P0966C
   39:03.974  Start of planned pitch rate
                maneuver                          63.964  V90R5321C
   39:04.670  Change in anomalous plume shape
              (LH2 tank leak near 2058 ring
              frame)                              64.660  E204 Camera
   39:04.715  Bright sustained glow on sides
               of ET                              64.705  E204 Camera
   39:04.947  Start SSME gimbal angle large
                pitch variations                  64.937  V58H1100A
   39:05.174  Beginning of transient motion due
                to changes in aero forces due to
                plume                             65.164  V90R5321C
   39:06.774  Start ET LH2 ullage pressure
               deviations                         66.764  T41P1700C
   39:12.214  Start divergent yaw rates
               (RH vs. LH SRB)                    72.204  V90R2528C
   39:12.294  Start divergent pitch rates
               (RH vs. LH SRB)                    72.284  V90R2525C
   39:12.488  SRB major high-rate actuator
                command                           72.478  V79H2111A
   39:12.507  SSME roll gimball rates 5 deg/sec   72.497  V58H1100A
   39:12.535  Vehicle max +Y lateral
               acceleration (+.227 g)             72.525  V98A1581C
   39:12.574  SRB major high-rate actuator
              motion                              72.564  B58H1151C
   39:12.574  Start of H2 tank pressure decrease
              with 2 flow control valves open     72.564  T41P1700C
   39:12.634  Last state vector downlinked       72.624 Data reduction
   39:12.974  Start of sharp MPS LOX inlet
              pressure drop                       72.964  V41P1330C
   39:13.020  Last full computer frame of TDRS
                 data                            73.010 Data reduction
   39:13.054  Start of sharp MPS LH2 inlet
              pressure drop                       73.044  V41P1100C
   39:13.055  Vehicle max -Y lateral
                accelerarion (-.254 g)            73.045  V98A1581C
   39:13.134  Circumferential white pattern on
              ET aft dome (LH2 tank failure)      73.124  E204 Camera
   39:13.134  RH SRM pressure 19 psi lower
              than LH SRM                         73.124  B47P2302C
   39:13.147  First hint of vapor at intertank    E207 Camera
   39:13.153  All engine systems start responding
              to loss of fuel and LOX inlet
                pressure                          73.143  SSME team
   39:13.172  Sudden cloud along ET between
              intertank and aft dome              73.162  E207 Camera
   39:13.201  Flash between Orbiter & LH2 tank    73.191  E204 Camera
   39:13.221  SSME telemetry data interference
              from 73.211 to 73.303               73.211
   39:13.223  Flash near SRB fwd attach and
               brightening of flash between
               Orbiter and ET                     73.213  E204 Camera
   39:13.292  First indication intense white
              flash at SRB fwd attach point       73.282  E204 Camera
   39:13.337  Greatly increased intensity of
               white flash                        73.327  E204 Camera
   39:13.387  Start RCS jet chamber pressure
                fluctuations                      73.377  V42P1552A
   39:13.393  All engines approaching HPFT
              discharge temp redline limits       73.383  E41Tn010D
   39:13.492  ME-2 HPFT disch. temp Chan. A vote
             for shutdown; 2 strikes on Chan. B   73.482  MEC data
   39:13.492  ME-2 controller last time word
                update                            73.482  MEC data
   39:13.513  ME-3 in shutdown due to HPFT discharge
              temperature redline exceedance      73.503  MEC data
   39:13.513  ME-3 controller last time word
                 update                           73.503  MEC data
   39:13.533  ME-1 in shutdown due to HPFT discharge
              temperature redline exceedance      73.523  Calculation
   39:13.553  ME-1 last telemetered data point    73.543  Calculation
   39:13.628  Last validated Orbiter telemetry
              measurement                         73.618  V46P0120A
   39:13.641  End of last reconstructured data
              frame with valid synchronization
              and frame count                    73.631 Data reduction
   39:14.140  Last radio frequency signal from
                Orbiter                          74.130 Data reduction
   39:14.597  Bright flash in vicinity of Orbiter
                nose                             74.587  E204 Camera
   39:16.447  RH SRB nose cap sep/chute
                deployment                       76.437  E207 Camera
   39:50.260  RH SRB RSS destruct               110.250  E202 Camera
   39:50.262  LH SRB RSS destruct               110.252  E230 Camera


Online Chris Bergin

Re: Challenger STS-51L
« Reply #22 on: 12/07/2005 03:03 PM »
Yes, same with Columbia on the huge efforts, but Challenger was having a lot more work to do with the SSMES, and the SRBs - even the wings at some point. Impossible situation all the same.

Offline SimonShuttle

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Re: Challenger STS-51L
« Reply #23 on: 12/09/2005 12:32 PM »
Was there any way they could have just seperated the boosters as soon as it was seen one was becoming critical, then do a RTLS or even ditch?

Online Chris Bergin

Re: Challenger STS-51L
« Reply #24 on: 12/09/2005 12:49 PM »
Well while it really all happened too fast, there's not a lot that can be done.

SRB sep would not of solved the problem with the ET being compromised.

Orbiter sep from the ET and SRBs would have flown the orbiter right into the ET or path of the SRB exhaust.

No win situation I'm afraid :(

Offline JamesSpaceFlight

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Re: Challenger STS-51L
« Reply #25 on: 12/09/2005 01:19 PM »
I've looked at the speed of the events, BA was a consultant on senario event investigation for any program the UK would undertake. There was nothing that could have been done. She was literally doomed from the second she left the pad.

Offline Orbiter Obvious

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Re: Challenger STS-51L
« Reply #26 on: 12/09/2005 03:23 PM »
Very sad. I'm more shocked about the forcing of the launch for Reagan. Is that comfirmed or is it just rumor?

Offline Dobbins

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Re: Challenger STS-51L
« Reply #27 on: 12/09/2005 03:56 PM »
Quote
Orbiter Obvious - 9/12/2005  11:23 AM

Very sad. I'm more shocked about the forcing of the launch for Reagan. Is that comfirmed or is it just rumor?

It's a long standing suspicion that could never be confirmed. NASA doesn't like making Presidents unhappy and making Reagan unhappy is something that would have been in the back of many minds in upper management.

John B. Dobbins

Offline Super George

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Re: Challenger STS-51L
« Reply #28 on: 12/09/2005 04:41 PM »
Yes, I think it was based on a rumor that the President wanted to include that a Teacher was able to travel into space on the ship he christened (STS-4 Columbia, end of test flights).

Personally I do not think that would mean NASA was forced to launch and Reagan wouldn't of had anything to do with the risk factor given the blow to the program that it ended up being.

Maybe NASA upper management didn't want to delay for the President, to keep him happy as he was the paymaster at the time. Maybe NASA didn't want to ruin their attempt to have that "year of the Shuttle" after just the second flight.

Whatever it was, it highlighted the arrogance of a time where NASA didn't listen to its contractors or itself when told to launch would be a major risk.

Offline Avron

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Re: Challenger STS-51L
« Reply #29 on: 12/09/2005 10:29 PM »
Quote
Super George - 9/12/2005  12:41 PM

Yes, I think it was based on a rumor that the President wanted to include that a Teacher was able to travel into space on the ship he christened (STS-4 Columbia, end of test flights).

Personally I do not think that would mean NASA was forced to launch and Reagan wouldn't of had anything to do with the risk factor given the blow to the program that it ended up being.

Maybe NASA upper management didn't want to delay for the President, to keep him happy as he was the paymaster at the time. Maybe NASA didn't want to ruin their attempt to have that "year of the Shuttle" after just the second flight.

Whatever it was, it highlighted the arrogance of a time where NASA didn't listen to its contractors or itself when told to launch would be a major risk.

And clearly violated the launch constraints...   this is not the same as our current foam issue... IMHO, one was NASA ( upper management) and the the other (foam) was and still is on the head of Lockmart or MSFC... but they seem to be covering each other.. Humm

Offline psloss

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Re: Challenger STS-51L
« Reply #30 on: 12/09/2005 11:00 PM »
Quote
Super George - 9/12/2005  12:41 PM

Whatever it was, it highlighted the arrogance of a time where NASA didn't listen to its contractors or itself when told to launch would be a major risk.
There was plenty of schedule pressure, particularly the Centaur launches off both pads during essentially the same week.  But there was also hubris in both shuttle disasters.

Challenger and the 51-L crew were the unlucky ones to be flying when that SRM design failed; however, proverbial bullets had already been dodged -- secondary O-ring erosion in both the case-to-case and the case-to-nozzle joints -- and given the increasing flight rate, I think something was going to break in trying to ramp up to the 24 flights per year they were shooting for back then.  (Possibly something besides the booster field joints.)

Offline Ben E

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Re: Challenger STS-51L
« Reply #31 on: 12/09/2005 11:43 PM »
Out of curiosity, what were the realistic chances of achieving the mammoth flight rates envisaged in the early 1980s. Admittedly, the 24-flights-per-year idea was ludicrous, but would NASA have been able to manage, say, the 14 flights planned for 1986. Was the Shuttle programme technically capable of doing it or would it have ended up similar to 1985 with 9-10 flights?


Online Chris Bergin

Re: Challenger STS-51L
« Reply #32 on: 12/10/2005 08:52 AM »
14 flights in 1986? Damn - I thought it was 12 and that was pushing it. I know they wanted to call it the year of the Shuttle, but I had no idea it was 14!

Offline psloss

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Re: Challenger STS-51L
« Reply #33 on: 12/10/2005 12:38 PM »
At the beginning of the year, I believe they had these "highlights":

* the Comet Halley ASTRO flight (61-E)
(Challenger was "holding up" Pad B, and Halley wasn't going to wait)

* The two interplanetary, shuttle/Centaur flights -- Ulysses and then Galileo (61-F/61-G)
(Atlantis was getting ready to go out to Pad A for Centaur tanking tests)

* The first Vandenberg launch (62-A)
(and possibly 62-B by the end of the year; that schedule was already slipping.  Perhaps someone here who was at KSC back then would know whether Discovery was going to be ready to support the rest of the pad validations, such as the planned FRF.  She was still at KSC on 28 January.)

* The HST deploy mission (61-J)

That's all I can recall mostly off the top of my head.

-- OK, now I'm cheating with Google: there was also the LDEF retrieval mission, too!  Here's the reference:
http://www.astronautix.com/articles/youelled.htm

Philip Sloss

Offline anik

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Re: Challenger STS-51L
« Reply #34 on: 12/10/2005 12:47 PM »
Quote
Chris Bergin - 10/12/2005  12:52 PM

14 flights in 1986?
Maybe 15 flights…

1 – January 12* – Columbia (61-C) – Satcom Ku-1, MSL-2;
2 – January 28* – Challenger (51-L) – TDRS-B, Spartan 203;
3 – March 6 – Columbia (61-E) – Astro-1;
4 – May 15 – Challenger (61-F) – Ulysses;
5 – May 21 – Atlantis (61-G) – Galileo;
6 – June 24 – Columbia (61-H) – Skynet 4A, Palapa B3, Westar 6S;
7 – July – Discovery (62-A) – DoD (Teal-Ruby);
8 – July 15 – Challenger (61-M) – EOS 1, TDRS-C;
9 – September 3 – Atlantis (61-K) – EOM-1/2;
10 – September – Columbia (61-N) – DoD (SDS B-1);
11 – September – Challenger (61-I) – Insat 1C;
12 – September – Discovery (62-B) – DoD (Lacrosse 1);
13 – October – Atlantis (61-J) – HST;
14 – November – Columbia (61-L) – MSL 3, Leasat 5, GStar 3;
15 – December – Challenger (71-B) – DoD (DSP F14).
* – actual launch date

I may have mistakes...

Offline Ben E

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Re: Challenger STS-51L
« Reply #35 on: 12/10/2005 01:32 PM »
It's also interesting to see how short the turnaround times were for individual orbiters in the pre-51L timeframe. Are there any reasons (technical or otherwise) how NASA achieved these six-week-to-two-month turnaround times in the 'olden days' and never again routinely achieved this post-51L? It surely can't all have been due to cost-cutting and safety compromises.

I think the post-51L record was just under three months for STS-83/94, but that was just because it was the same payload on both missions. Generally, post-51L turnarounds have averaged four to six months.

Any explanations why?

Offline anik

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Re: Challenger STS-51L
« Reply #36 on: 12/10/2005 02:48 PM »
According to http://www.astronautix.com/project/sts.htm

1. Atlantis (61-G) should be launched on May 20 (not on May 21);
2. Challenger (61-M) should be launched on July 22 (not on July 15);
3. Atlantis (61-J) should be launched in August (not in October);
4. 61-N should be launched on Discovery (not on Columbia) on September 4;
5. Challenger (61-I) should be launched on September 27;
6. Discovery (62-B) should be launched on September 29;
7. 61-K should be launched on Columbia (not on Atlantis) in October (not on September 3);
8. 61-L should be launched on Atlantis (not on Columbia).

P.S.: Between Challenger (61-F) and Atlantis (61-G) launches were 5 days!
PP.S.: Between Discovery launches from KSC (61-N) and from VAFB (62-B) were 25 days!

Offline David AF

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Re: Challenger STS-51L
« Reply #37 on: 12/10/2005 04:09 PM »
That is amazing. If they had only pulled it off the USAF would not have pulled out and we might have a different story now on the cash.
F-22 Raptor instructor

Offline Ben E

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Re: Challenger STS-51L
« Reply #38 on: 12/10/2005 05:58 PM »
I was always under the impression that 61N was actually a Columbia mission and have drawn attention to it in my book SPACE SHUTTLE COLUMBIA. A couple of years ago, I spoke to 61N Commander Brewster Shaw, who told me that at the time of the 51L disaster he was expecting to fly a classified DoD mission aboard Columbia in the autumn. The original 61N crew, minus Pilot Mike McCulley and Payload Specialist Frank Casserino, eventually flew Columbia on STS-28.

I very much doubt that, even in the optimistic pre-51L days, a 25-day turnaround would have been possible, let alone a turnaround which also involved flying from coast to coast to launch from different sites.

I think the all-time turnaround record, actually achieved, was about 51 days for Atlantis on the 51J/61B turnaround, in which she landed from her first mission on October 7th 1985 and next launched on November 27th. Correct me if I'm wrong, but I don't think the Shuttle ever beat that.


Offline ADC9

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Re: Challenger STS-51L
« Reply #39 on: 12/10/2005 07:20 PM »
And they shouldn't be looking to beat it. I'd sooner of seen a less overdone schedule because I honestly think it's a reciepe for disaster.

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