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Author
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Topic: Gemini 8: Negating the spacecraft tumbling
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MCroft04
Member Posts: 1647
From: Smithfield, Me, USA
Registered: Mar 2005
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posted 11-22-2006 07:13 PM
   
I've read numerous explanations of how Neil and Dave resolved their tumbling problem, but the best explanation I can come up with is that they activated the reentry system. However I don't understand how this negated the violent spin that they were in. Does anyone know how the activation of the reentry system saved them? |
micropooz
Member Posts: 1532
From: Washington, DC, USA
Registered: Apr 2003
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posted 11-22-2006 08:19 PM
The re-entry system was a separate set of thrusters from the Orbit Attitude and Maneuvering System (OAMS) thrusters, one of which stuck on, causing the spin. They had to shut off the OAMS system to keep from accelerating their spin, then use the re-entry system to stop the spin. You can see the re-entry jets around the nose of the Gemini command module, just ahead of the conical crew compartment. |
MCroft04
Member Posts: 1647
From: Smithfield, Me, USA
Registered: Mar 2005
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posted 11-22-2006 08:46 PM
Thanks for the info. It seems like a complicated procedure to stop a spin in 3 axis, even after the OAMS was shut down. Any idea exactly how the reentry system was able to do this? Was it automatic or did Neil and Dave have to control it manually? |
Michael Davis
Member Posts: 530
From: Houston, Texas
Registered: Aug 2002
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posted 11-23-2006 05:29 PM
It was a manual process. |
MCroft04
Member Posts: 1647
From: Smithfield, Me, USA
Registered: Mar 2005
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posted 11-23-2006 09:00 PM
Thanks; I've already gotten the details offline. |
Fra Mauro
Member Posts: 1624
From: Bethpage, N.Y.
Registered: Jul 2002
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posted 11-29-2006 09:53 AM
I never understood the rumored rumblings among some in the Astronaut Office that the crew screwed up the mission. |
leslie
Member Posts: 231
From: Surrey, England
Registered: Aug 2005
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posted 11-29-2006 10:07 AM
I learned from Professor Armstrong earlier this year that "although we simulated many types of control failures, they never had that one" and he stated further "the problem was the unpredictability of the vehicle motions and control responses".Clearly he saw the situation as control failures rather than crew error! This is part of a response to a question of mine regarding career "worst moments." |
robertsconley
Member Posts: 59
From: Meadville, PA
Registered: Jun 2005
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posted 11-29-2006 12:53 PM
quote:
Originally posted by Fra Mauro:
I never understood the rumored rumblings among some in the Astronaut Office that the crew screwed up the mission.
Well the best case scenario would have been that Ground control working with the crew figured out which OAMS thruster was faulty and saved the mission. Once they brought up the RCS the mission had to be aborted.But given the timing of the problem starting it is very unlikely anything better could have been done. Like anything crew of Scott and Armstrong had choices on how to deal with the problem and some people will always use hindsight to say that there was a better way to deal with it. For example the OAMS could have been shut down and each thruster brought up until the faultly one was found. Then control could have been regained by using the remaining OAMS thrusters. But that ignores the fact that - The Agena was less trusted than the Gemini. So in the event of control problems the first rule was get away from the Agena.
- There are no indicators for which thrusters are firing on the Gemini
- Detaching from the Agena made the problem worse.
- Shutting down the OAMS still left them with the current rate of rotation.
- Trying to figure out which OAMS was faulty could only add to the problem until isolated.
- Gemini was not like Mercury and needed pilots to fly it.
So in the end the only realistic option was to keep the OAMS shut down and go with the RCS. It sucked they lost the EVA but the most import goal of docking was achieved. |
micropooz
Member Posts: 1532
From: Washington, DC, USA
Registered: Apr 2003
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posted 11-29-2006 01:20 PM
Well, if negative rumblings occurred in the crew office, they weren't strong enough to dissuade Slayton from sending both Armstrong and Scott on to bigger and better assignments. If Slayton had thought they screwed up, they would have been relegated to the bench or maybe Apollo Applications. |
FFrench
Member Posts: 3165
From: San Diego
Registered: Feb 2002
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posted 11-29-2006 01:59 PM
I've always found it interesting how differently they were assigned, however. Only five days after returning from Gemini 8, Scott was assigned to an Apollo crew. A sign of confidence in him, I'd say. Armstrong, however, had a dead-end job backing up Gemini 11, meaning he would not fly Gemini again, nor be immediately available for an early Apollo crew if Gemini and Apollo flew as scheduled. Without the delay caused by the Apollo 1 tragedy, would he have been available to back up (what became) the second Apollo mission, thus rotating to prime crew for 11? |
Michael Cassutt
Member Posts: 358
From: Studio City CA USA
Registered: Mar 2005
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posted 11-29-2006 11:18 PM
Not so fast, Francis. Scott was rotated to the A1 backup crew because Slayton wanted a rendezvous-experienced, flight-experienced CMP for McDivitt's crew, which was aimed at the first manned LM test. Had Bassett lived, and flown a successful GT-9 rendezvous, he would have gone to Borman's A2 backup team in the same role.But that was all Slayton needed at the time. (The Block II crews weren't named until after Gemini was complete.) None of the last three backup crews were truly "dead end" -- that label comes from Walt Cunningham -- and is precisely as accurate as some of Walt's other characterizations. (Which is to say, it's his opinion, not universal fact.) Had A1 and Grissom's crew flown as hoped in February 1967, you might have seen Armstrong rotating from backup cdr G11 to prime cdr A4. I don't think there's any evidence that Slayton, Gilruth, Mueller or others ever lost faith in Armstrong because of G8. |
FFrench
Member Posts: 3165
From: San Diego
Registered: Feb 2002
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posted 11-30-2006 12:50 AM
Thanks Mike - that makes sense - especially as Armstrong, as I understand it, had already been assigned to the Gemini 11 backup slot before the Gemini 8 mission - not as a consequence of it. |
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