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Author
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Topic: Apollo abort calls, decisions and crew options
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Jouett
Member Posts: 53
From: Fishers, IN, USA
Registered: Aug 2016
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posted 09-02-2016 08:51 PM
  
I've just gotten into the Apollo-era space program in the last few months. I've been thinking and had some beginner questions... - I know of the close call aborts from the Steve Bales Apollo 11 1201 error, the Apollo 11 landing where it was a close call with fuel, and Aaron's SCE to Aux with Apollo 12. Was there ever an actual split second abort call made in any of the Mercury, Gemini or Apollo missions by the crew or Mission Control?
- If Mission Control were to make an abort call, would the ultimate decision be made by the crew? In other words, could it be overridden by the crew?
- Using Apollo 11 as an example, if something were to have happened to Armstrong and Aldrin on the moon, could Collins have made it home by himself? Or did the tasks necessary to get back home require a two or three man crew in the Command Module?
Thanks everyone. Love the site. — Brian |
David C
Member Posts: 1039
From: Lausanne
Registered: Apr 2012
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posted 09-02-2016 10:52 PM
The only split second decision I can think of was on Gemin 6A. That was the December 12, 1965 launch attempt when the Titan II shut down 1.5 seconds after ignition and Schirra and Stafford decided not to eject.Unless an abort is automatically initiated, any abort call made by mission control can be overridden by the crew. As they say in the flying business — no stick, no vote. But, this is extremely unlikely. Firstly, especially in Mercury, Gemini and Apollo, the crew had sat through numerous mission rules meetings with the flight controllers effectively pre-deciding all this stuff. The crew understood the rationale and wanted to live! Secondly, the boosters had range safety destruct explosive packages that would be command destructed by the RSO. A decision to ignore mission rules and "ride it out" better be accompanied by darned good communications. On Mercury and Apollo, some launch failures would trigger an automatic abort under certain conditions. The system was automatically armed on Mercury and manually armed on Apollo. Either way, once armed, if it made an abort decision it could not be crew overridden. Yep, Collins and all solo flight command module pilots from Apollo 10 onwards were trained to come back on their own. Not sure about Apollo 9 since McDivitt, not Scott, "flew" the entry. For a Mercury, Gemini, Apollo beginner, I can't think of a better starting point than Mike Collin's book "Carrying the Fire," and he covers some of this stuff there. |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 09-03-2016 02:02 AM
If I may add to the above. During a Saturn V launch there were four modes of escape (abort) and calls were made to the crew as to which of the four routes to safety were appropriate. Briefly, they were - - MODE ONE - the launch escape tower propels the CM away from the launch vehicle landing it anywhere from the immediate vicinity of the launch pad to 964 kms downrange. This mode operated from about twenty minutes before launch when the escape rocket was armed until tower jettison some 195 seconds after lift-off. The CapCom for the flight would inform the crew as to where they were expecting to land by calling 'Mode One Bravo' at some 40 seconds into the flight and 'Mode One Charlie' at about 110 seconds. These calls would determine landing points, chute deployment and other specifics that depend on the exact time of the abort.
- MODE TWO - this followed after tower jettison and continued until the SPS engine could be used to place the CSM into a safe orbit or until the African coast was threatened by a landing. This mode required a manual separation and re-entry orientation with a landing coming anywhere from 741 to 931 kms downrange. The mode two call typically came about 200 seconds into the flight.
- MODE THREE - began when the CM using its full lift capacity could reach a downrange distance of 5931 kms and extended through to orbital insertion. The CSM would be separated from the launch vehicle and a retrograde burn made if needed. The CM would then be flown to a landing point some 6197 kms downrange.
- MODE FOUR - used once the SPS engine could be used to insert the CSM into orbit and was usually the method adopted during the last seconds of the S-IVB burn. This was the mode that was generally preferred over mode three.
Hope this helps. |
oly
Member Posts: 971
From: Perth, Western Australia
Registered: Apr 2015
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posted 09-03-2016 05:25 AM
If in fact there was a problem and the two crew could not return to the CSM and a single crew member was forced to return solo to Earth, how much effect would this reduced weight and change to the centre of gravity of the command module have on the velocity and flight dynamics of the re-entry? |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 09-03-2016 06:51 AM
Wasn't this a problem on Apollo 13 where the lack of lunar samples caused a late change to the re-entry parameters? |
Robert Pearlman
Editor Posts: 43576
From: Houston, TX
Registered: Nov 1999
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posted 09-03-2016 08:13 AM
Odyssey's guidance computer had been pre-programmed to expect an additional hundred pounds or so of moon rock on board, so a revised entry stowage list was called up to the crew that included additional equipment from Aquarius. |
Paul78zephyr
Member Posts: 678
From: Hudson, MA
Registered: Jul 2005
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posted 09-03-2016 06:46 PM
quote:
Originally posted by David C:
Yep, Collins and all solo flight command module pilots from Apollo 10 onwards were trained to come back on their own. Not sure about Apollo 9...
That is an interesting statement with respect to Apollo 7-9. Were all Apollo crew members trained to perform a "solo" re-entry - whether actually alone (Apollo 9) or with other crew incapacitated (Apollo 7, Apollo 8)? Same for Gemini? |
Jouett
Member Posts: 53
From: Fishers, IN, USA
Registered: Aug 2016
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posted 09-03-2016 09:36 PM
Thanks everyone for your comments. Very interesting stuff.Nice to hear about Mike Collin's book "Carrying the Fire" as I already own a copy. Just haven't started reading it yet. Just finished Kranz's "Failure is not an Option". Really enjoyed it. Did a search on the top Apollo era books and saw that "Carrying the Fire" was a must have. Thanks again! |
David C
Member Posts: 1039
From: Lausanne
Registered: Apr 2012
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posted 09-04-2016 09:56 AM
quote:
Originally posted by Paul78zephyr:
Were all Apollo crew members trained to perform a "solo" re-entry...
No. I guess CDRs would cope a lot better than LMPs, depending on what other malfunctions they had.I suspect the same is true of Gemini. I guess with a more traditional cockpit layout and central hand controller, either guy would have coped. |
Paul78zephyr
Member Posts: 678
From: Hudson, MA
Registered: Jul 2005
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posted 09-04-2016 07:33 PM
quote:
Originally posted by Jouett:
Just haven't started reading it yet.
And when you finish Collins' book you MUST read "How Apollo Flew To The Moon" by W. David Woods. Not a bio or a retrospective - just all the nuts and bolts of how they did it. |
oly
Member Posts: 971
From: Perth, Western Australia
Registered: Apr 2015
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posted 09-05-2016 10:36 AM
Is anyone aware of what the contingency plan for any loss of crew during lunar activity either on the lunar surface or while the command module and lunar module were separated? Is there an emergency contingency flight plan that addresses the CSM earth return solo flight and what the effects on the flight dynamics would be? If the guidance computer was pre-programmed for the weight of three crew plus lunar sample weight would any re-entry have to be flown manually? An underweight CSM would have different velocity and centre of gravity that would change many aspects of the flight. Could the CSM be operated during re-entry, parachute deployment and splashdown by a solo crew member? |
indy91
Member Posts: 15
From: Germany
Registered: Feb 2016
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posted 09-05-2016 11:01 AM
I can at least answer the question regarding the guidance computer. The trim angle of attack and the lift-to-drag ratio of the command module are numbers loaded into the erasable memory of the computer before launch. But these numbers can be changed during the flight and account for a different center-of-gravity than predicted. I'm sure there is a limit for the computer to be able to handle such a change, but only one instead of three crewmember shouldn't have been a problem for an automatic reentry. |
Jim Behling
Member Posts: 1488
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 09-05-2016 12:55 PM
quote:
Originally posted by oly:
Could the CSM be operated during re-entry, parachute deployment and splashdown by a solo crew member?
Yes, it was specifically designed to be controlled by one crewmember for longer periods and for more operations from and including TEI to splashdown. |
schnappsicle
Member Posts: 396
From: Houston, TX, USA
Registered: Jan 2012
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posted 09-06-2016 09:59 AM
Another question begging to be answered is why not just re-program the reentry program on Apollo 13? Wouldn't that be much easier than trying to balance everything with junk from the LM? Did crew fatigue have anything to do with the decision? |
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