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Author
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Topic: Mercury to Gemini transfer
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moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 10-24-2010 07:07 AM
   
Given that the two craft just about overlapped in flight status, would it have been possible for a stranded Mercury astronaut to have been rescued by a Gemini?What problems might have made this impossible? |
SpaceAholic
Member Posts: 4494
From: Sierra Vista, Arizona
Registered: Nov 1999
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posted 10-24-2010 08:44 AM
Aside from Mercury having no EVA capability, no way to tether the two flight vehicles for the transfer (necessary since they couldnt dock), and the Goodrich suit being non-interoperable with the Gemini ECS, none that I know of...One possible solution would be to provision for extended umbilicals supplied from the Gemini capsule and modified to interface with the Mercury spacesuit, and assuming good station keeping between the two vehicles, using nitrogen zip guns for mobility/transfer. The problem with station keeping is that blowing the Mercury hatch will result in undesired impulse which would most likely impart a significant yaw to the vehicle - this would have to be brought under control before the approaching Gemini astronaut could rendevouz with the Mercury capsule and supply the needed umbilical(s). |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 10-24-2010 01:00 PM
I have to say that I agree with you. However, a problem I can see is how would one preserve the suit integrity of the Mercury astronaut when he uncoupled from the capsule ECS? How much time would there be before the loss of pressure/breathable oxygen reached dangerous levels? Would there be sufficient time to make the necessary connections to the Gemini life support systems? Would it be possible to seal the system to enable this to be done? |
Obviousman
Member Posts: 438
From: NSW, Australia
Registered: May 2005
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posted 10-24-2010 09:31 PM
Would the Mercury suit be suitable for an EVA, even a relatively brief one? |
SpaceAholic
Member Posts: 4494
From: Sierra Vista, Arizona
Registered: Nov 1999
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posted 10-24-2010 10:44 PM
It's a full pressure suit (designed for decompression) and could sustain life for a limited period in a vacuum. Managing thermal exposure and loss of mobility would be the biggest challenge. Any hypothetical rescue would have to address the suit inlet, vent (outlet) and a pneumatic connection to ensure continued inflation of the helmet seal. |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 10-25-2010 07:21 AM
quote:
Originally posted by SpaceAholic:
....a pneumatic connection to ensure continued inflation of the helmet seal.
This seal was to ensure the integrity of the suit visor surely. However, would this have, in itself, prevented a transfer? It would depend, would it not, on leakage rates and how much time elapsed before these reached dangerous levels. |
kr4mula
Member Posts: 642
From: Cinci, OH
Registered: Mar 2006
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posted 10-25-2010 11:08 AM
Given the ingenuity of the Crew Systems Division people and their contractors, not to mention the relatively primitive state-of-the-art technology, I would bet that NASA and BF Goodrich (or perhaps the ECS folks) could design and fabricate a simple pressurized oxygen bottle system that the astronaut could hook up to his suit connectors, not unlike the OPS in Apollo, perhaps. I don't even think a vent would be necessary for the short term. Devising a system would surely take less time that readying a Gemini flight and all the other activities necessary to effect a rescue. Of course, the Gemini rescuer would have to deliver the bottle to his stranded colleague. The Mercury suit wouldn't have to be compatible with the Gemini ECS because the capsule stayed pressurized on the way down, except if there was some sort of failure, in which case, the Mercury guy could turn on his air bottle again. The bigger question, of course, is where would the Mercury guy sit in the Gemini capsule? I imagine the Gemini could get along ok with one pilot on the ride up, though managing the intricacies of the rendezvous, EVA, tether, and everything else would be quite challenging for a single astronaut. |
onesmallstep
Member Posts: 1313
From: Staten Island, New York USA
Registered: Nov 2007
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posted 10-26-2010 04:03 PM
Given the (relatively) different types of equipment and problems with interfacing them, I think it would have been difficult, if not impossible, to achieve. I'm reminded of the scene in the movie 'Marooned' where a then-Soviet cosmonaut did a spacewalk over to the crippled American CM and its two remaining astronauts and attempted to hook up an oxygen hose (his or another's?) in a rescue attempt. In any event, another US astronaut who launched aboard an X-20 Dyna-Soar spacecraft rendezvoused with them and, using an early version of the Shuttle-era MMU, went over and completed the rescue and return of the astronauts. In the hypothetical Mercury-Gemini rescue, I think three things would need to be in place for it to succeed: -Early progress on a 'jet gun' like that used by Ed White on Gemini 4;
-Prototypes of the tether system used to link Geminis with unmanned Agenas;
-Extra consumables on the stranded Mercury capsule to keep its occupant alive unitl a rescue-perhaps he would have been Al Shepard aboard Freedom 7 II, who lobbied hard for an extra flight? Another problem to consider is the size and bulk of a fully pressurized Mercury suit-it was certainly designed for use by an astronaut, sitting down, and not for walking (space- or earth- wise). I think you would have to lower the pressure in it to be able to squeeze (literally) into the Gemini safely and avoid a problem like Leonov had after his walk on Voskhod 2.. |
Lou Chinal
Member Posts: 1332
From: Staten Island, NY
Registered: Jun 2007
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posted 10-26-2010 11:15 PM
Only Gordon Cooper's helmet did not need a visor gas seal. His was different from all the others, in that it closed mechanically.I would have to assume that a Gemini was already on the pad, ready to go. The Commander would also have to open the pilot's hatch (not an easy thing to do). The original design for the Mercury suit was to support an astronaut for one orbit (90) minutes. |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 10-27-2010 03:26 AM
quote:
Originally posted by onesmallstep:
-Early progress on a 'jet gun' like that used by Ed White on Gemini 4;
-Prototypes of the tether system used to link Geminis with unmanned Agenas';
Why these two? In the first case, providing the Gemini astronaut was firmly attached to his craft and the two capsules were close enough a simple shove would be sufficient to take him to the Mercury. By this time one has to assume that the hatch would have been blown so there would have been handholds round the edges of the opened hatch.In the second case, why would the two capsules need to be tethered to effect a rescue? Once the Gemini astronaut has a firm hold on his Mercury colleague what happens to the Mercury capsule becomes irrelevant. |
SpaceAholic
Member Posts: 4494
From: Sierra Vista, Arizona
Registered: Nov 1999
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posted 10-27-2010 05:33 AM
quote:
Originally posted by moorouge:
Why these two?
Newton's laws of motion apply even in Space..what do you think the behavior of spacecraft will be once either, or both astronauts "kick off" their respective capsules for propulsive energy (an asymmetric impulse) to make that transit? |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 10-27-2010 06:06 AM
quote:
Originally posted by SpaceAholic:
Newton's laws of motion apply even in Space..what do you think the behavior of spacecraft will be once either, or both astronauts "kick off" their respective capsules for propulsive energy (an asymmetric impulse) to make that transit?
Agreed. But, surely, the degree of 'propulsive energy' if the two spacecraft were sufficiently close (Gemini 6 station kept within 18 inches of Gemini 7) would be relatively small and would it not be negated once the Gemini astronaut had a firm hold on the Mercury capsule? |
SpaceAholic
Member Posts: 4494
From: Sierra Vista, Arizona
Registered: Nov 1999
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posted 10-27-2010 06:30 AM
Two low mass spacecraft (consider that the Mercury coarse attitude control and Gemini RCS thrusters only required a rated output of less then 25 pounds/~100 newtons thrust to effect or neutralize attitude changes). As soon as that Gemini astronaut "steps-off" his capsule, the range will open and the vehicle will start to tumble (depending on the rate of increasing separation, now you have to contend with a potential collision). Conversely as that transferring Gemini astronaut grabs the Mercury capsule, his momentum will be imparted to the even smaller spacecraft with the same dynamics at work. See the light? |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 10-27-2010 10:49 AM
Dimly. Can't remember Gemini 4 tumbling when White stepped out for his EVA. Would have thought that firing the thrusters to correct any motion would have placed White in jeopardy anyway. Since in our scenario we are assuming a relatively close proximity, surely the Gemini astronaut, on a tether as was White, once he had grabbed the Mercury pilot, any motion of the Mercury capsule does not become a factor. Both astronauts would now be attached to the Gemini capsule and, by definition, be linked to any imparted motion that had been induced. |
SpaceAholic
Member Posts: 4494
From: Sierra Vista, Arizona
Registered: Nov 1999
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posted 10-27-2010 11:04 AM
White drifted out using his gun for impulse... I'd bet McDivitt was also providing input to the ACME to stabilize attitude during the EVA... |
kr4mula
Member Posts: 642
From: Cinci, OH
Registered: Mar 2006
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posted 10-27-2010 11:39 AM
Assuming only one Gemini astronaut rescuer, there wouldn't be anyone in the Gemini capsule (once he went EVA) to maintain its attitude and orientation and proximity to the Mercury capsule.Keep in mind that Gemini plans didn't include EVA until a later flight. It required a couple of months of "crash" effort to get the suit and zip gun prepared for Gemini IV once the astronaut's lobbying to do it prevailed. That means that Gemini III (presuming that only the first manned Gemini flight would be close to overlapping the final Mercury mission) would not have been able to do an EVA at all, much less one as complicated as a rescue. And I doubt the stranded Mercury capsule would be able to hold out long enough to get all of the gear ready. Given the difficulties of the later EVAs, can you imagine doing all this rescue work without even one EVA under NASA's belt? Yikes! Not that they wouldn't have tried if it were at all feasible, given the can-do attitude of the times, but it wouldn't have been pretty. By the way, I'm always intrigued by these creative "what-if" scenarios that our members concoct, and am always impressed by the depth of thinking that goes into the replies. |
kr4mula
Member Posts: 642
From: Cinci, OH
Registered: Mar 2006
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posted 10-27-2010 11:42 AM
quote:
Originally posted by moorouge:
Would have thought that firing the thrusters to correct any motion would have placed White in jeopardy anyway.
NASA did extensive mission planning to ensure that this didn't happen. I seem to recall them deactivating thrusters in the areas where the EVA astronaut would be, at least for the later Gemini-Agena flights. |
SpaceAholic
Member Posts: 4494
From: Sierra Vista, Arizona
Registered: Nov 1999
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posted 10-27-2010 11:51 AM
Pretty easy to segregate - OAMS would have been used for attitude control (at the rear), with the EVA occurring forward of the spacecraft and the RCS system inactive. There were also individual toggles for solenoids associated with each of the thrusters. |
garymilgrom
Member Posts: 1966
From: Atlanta, GA
Registered: Feb 2007
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posted 10-27-2010 01:03 PM
Both astronauts would now be attached to the Gemini capsule and, by definition, be linked to any imparted motion that had been induced. I don't think so. The tether between them and the capsule allows freedom of movement from the capsule. |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 10-28-2010 03:13 AM
quote:
Originally posted by kr4mula:
Keep in mind that Gemini plans didn't include EVA until a later flight. It required a couple of months of "crash" effort to get the suit and zip gun prepared for Gemini IV once the astronaut's lobbying to do it prevailed.
Not strictly correct. In early 1963 McDonnell were asked to build into the Gemini capsule an EVA capability from #4 on.In January 1964 it was planned for GT-4 to include a depress and stand-up EVA with a full EVA scheduled for GT-5. Later, on 27th July the flight plan for GT-4 was announced as including that ".. an astronaut would first be exposed to the hazards of outer space." By October 1964 the first EVA suit was ready for testing and in March 1965 the crew were using them in tests in the high altitude test chambers. The possibility of a full EVA for GT-4 was discussed and agreed on 29th March 1965. All the equipment needed was flight qualified and at the Cape by the 19th May. The only piece of equipment that might be considered to be 'crash' ready was the zip gun. A prototype was demonstrated at the meeting on 29th March. It was the only piece that didn't come up to expectation on the flight. At the time of the mission it was widely reported that White's EVA was a last minute inclusion to match that of Leonov's. As can be seen, there were plans for an EVA before this event, though the Russian's exploit may have concentrated the thinking at NASA. |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 10-28-2010 05:16 AM
Can I try to pull some of the comments together about this scenario. First though a little background. In October 1963 Richard Carley was proposing a first orbit apogee rendezvous, this being followed in the following March when Aldrin advocated a concentric rather than a tangential approach to rendezvous as it offered more possibilities. As a direct bearing on the rescue of stranded astronauts, in July 1964, when discussions were taking place about possibly extending the Gemini programme, one of the proposals included was for life-boat missions.So, this is how I see a possible rescue mission: - Gemini makes first orbit rendezvous with the Mercury capsule and station keeps about 100ft away
- Mercury astronaut blows hatch and Gemini pilot opens both hatches (the difficulty that might be experienced to do this has been mentioned)
- Induced rates are stabilised by both capsules
- Gemini closes with the Mercury hatch to hatch getting as close as possible - 6 - 10ft would not be an unreasonable distance
- Gemini astronaut floats out of capsule and assists Mercury pilot to disconnect his ECS and plug into either a portable one as proposed or into an extended umbilical from the Gemini (difficulties mentioned are that the two craft would not be stable enough for this to be achieved; another one is how would the Mercury astronaut cope with the loss of suit integrity for the brief (?) period he is disconnected from his ECS; another problem mentioned is the pressure needed to seal the helmet visor though this was eliminated by the later Mercury suits which had a mechanical seal for the visor)
- Both astronauts transfer back to the Gemini using either a tether or the umbilical to pull themselves across the gap
- The Mercury astronaut is fed into his seat (a difficulty raised is the characteristic of the Mercury suit which adopted a sitting posture when pressurised though one might think that this would help)
- Gemini pilot resumes his place and the hatches are closed and the Gemini capsule repressurised
- Separation and de-orbit burns as normal.
Other considerations were that the early design requirement for the Gemini capsule was for a basic thirty minute capability for an EVA. Could the rescue as outlined above be accomplished in that sort of time scale? As a mission I would envisage it lasting no longer than two orbits or about three hours. Undoubtedly I've missed things, so your comments are most welcome. |
Byeman
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posted 10-28-2010 07:36 AM
quote:
Originally posted by moorouge:
Gemini astronaut floats out of capsule and assists Mercury pilot to disconnect his ECS
This is not viable.a. The Gemini astronaut can not open the opposite hatch b. The Gemini spacecraft has to have a pilot for station keeping. The very act of the pilot leaving would push the Gemini away from the Mercury |
capoetc
Member Posts: 2178
From: McKinney TX (USA)
Registered: Aug 2005
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posted 10-28-2010 08:32 AM
I guess I don't understand the basic premise of this thread. Are you trying to figure out if a Gemini could rescue a stranded Mercury crewman if Project Mercury had been extended so that it was still in progress after Gemini started?Gemini 6A (first rendezvous) was in Dec 1965, and Cooper's MA-9 was in May 1963. |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 10-28-2010 09:27 AM
quote:
Originally posted by capoetc:
I guess I don't understand the basic premise of this thread. Are you trying to figure out if a Gemini could rescue a stranded Mercury crewman if Project Mercury had been extended so that it was still in progress after Gemini started?
The very first post on this thread said, "Given that the two craft just about overlapped in flight status, would it have been possible for a stranded Mercury astronaut to have been rescued by a Gemini?" |
garymilgrom
Member Posts: 1966
From: Atlanta, GA
Registered: Feb 2007
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posted 10-28-2010 10:15 AM
I don't understand the basic premise of this thread either (and I'm quite capable of reading the original post). Why are you trying to plan, on a minute-by-minute timeline, something that never happened over 40 years ago? Because it might have happened? I don't understand that. Anything might have happened with the necessary forethought and plannning. I might recover a used S1C stage from the ocean floor, and I might have the engines repaired (any Chrysler mechanic should have a shop manual), and I might find a lake full of RP1 in my yard, and I might be gifted a few thousand gallons of LOX, and I might strap myself to the front of this contraption and trick Gilbert into lighting the thing. Is the possibility of this happening worth discussing? I don't think so. |
onesmallstep
Member Posts: 1313
From: Staten Island, New York USA
Registered: Nov 2007
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posted 10-28-2010 10:50 AM
I guess the main reason we indulge in these 'what if' scenarios is to test our knowledge of spacecraft and NASA history, if for no other excuse. Ever since Apollo 13 and the Skylab 1 repair missions, the ground controllers and support personnel have certainly gotten their due in solving difficult problems that come up in spacflight. One more problem in getting the Mercury astronaut out of his capsule is the matter of his suit pressurization: assuming the hatch is blown (and his gloves/knuckles aren't injured like John Glenn's), how will he squeeze out of the cabin, since even shoehorning him in while on the launch pad is a tight fit? Wouldn't an exit from the top of the capsule (if it was viable) be better? No blown hatch=no change in distance/station keeping from the rescue Gemini. |
jasonelam
Member Posts: 691
From: Monticello, KY USA
Registered: Mar 2007
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posted 10-28-2010 11:57 AM
I agree. I think the main purpose of these types of discussions is to see what our take would be on an approach. We've actually had discussions like this before (see "Deke for a Day" discussion board) and have found some interesting results. Some controversial, and all very interesting. Discussions like these are, for lack of a better phrase, alternative history, in which we look at ideas that might have occurred if things happened in a set way. It allows cS'ers to use their knowledge to create interesting answers. I personally think it is great to see this kind of response. As for getting out of the Mercury capsule, I think that it would not be an easy task, perhaps impossible. Whenever an astronaut climbed into or out of a Mercury, it was in an unpressurized suit, and that was a tight fit in of itself. Climbing out through the main hatch in a pressurized suit would have been hard, and through the top almost impossible. |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 10-28-2010 01:34 PM
quote:
Originally posted by garymilgrom:
Why are you trying to plan, on a minute-by-minute timeline, something that never happened over 40 years ago?
I'm not trying to plan anything. The list of events was put in to quantify in a logical, progressive manner what others had perceived as problems which could have made such a rescue impossible to achieve.However, I repeat that had Gemini been extended beyond GT-12 there were discussions, among other uses, about its function as a means of rescue. This said, two people have mentioned that it would have been impossible for the Gemini pilot to open the other hatch. Given that the hatches were hinged on the outer side of the capsule, does this not mean that the latches were towards the centre? If this is so, what would prevent the pilot reaching both sets? |
kr4mula
Member Posts: 642
From: Cinci, OH
Registered: Mar 2006
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posted 10-29-2010 11:01 AM
I wouldn't see the Gemini hatch issue as a significant problem. Again assuming that NASA had a couple days to sort things out, they probably could develop some sort of lever arm mechanism that would allow the commander to open the pilot's hatch. Closing it would be the more difficult task alone, but of course you'd have the Mercury guy sitting in that seat to do it. |
SpaceAholic
Member Posts: 4494
From: Sierra Vista, Arizona
Registered: Nov 1999
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posted 10-29-2010 02:37 PM
An external handhold, in the proper position/orientation integral to the spacecraft would be required to operate the tool. |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 10-29-2010 04:55 PM
quote:
Originally posted by SpaceAholic:
An external handhold, in the proper position/orientation integral to the spacecraft would be required to operate the tool.
Surely the hatches were opened from inside the Gemini. So why would they need an external hand-hold? And what tool was needed?If you are referring to the Mercury capsule, again no tools are needed. The astronaut just blows the hatch using the built in pyrotechnic bolts. |
SpaceAholic
Member Posts: 4494
From: Sierra Vista, Arizona
Registered: Nov 1999
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posted 10-29-2010 05:15 PM
Agreed... misread the post and thought it referred to the Mercury capsule. |
Robert Pearlman
Editor Posts: 43576
From: Houston, TX
Registered: Nov 1999
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posted 10-29-2010 05:42 PM
quote:
Originally posted by moorouge:
The astronaut just blows the hatch using the built in pyrotechnic bolts.
As we know from Grissom and Schirra, this would prove at best worrisome, as blowing the hatch could result in significant damage to the astronaut's pressure suit, rendering the need for a rescue by Gemini moot. |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 10-30-2010 03:01 AM
Damage to suits? Grissom got into trouble because he failed to secure the neck dam. What other damage occurred? |
Robert Pearlman
Editor Posts: 43576
From: Houston, TX
Registered: Nov 1999
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posted 10-30-2010 03:22 AM
Schirra manually blew the hatch on Sigma 7 after he was on the deck of the recovery ship. From his book, "Schirra's Space" (emphasis mine):When I was recovered, I remained in my spacecraft until being hoisted aboard the recovery ship. I then blew the hatch on purpose, and the recoil of the plunger injured my hand -- it actually cut through a glove that was reinforced by metal. Gus was one of those who flew out to the ship, and I showed him my hand. "How did you cut it," he asked. "I blew the hatch," I replied. Gus smiled, vindicated. It proved he hadn't blown the hatch with a hand, foot, knee or whatever, for he hadn't suffered even a minor bruise. |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 10-30-2010 05:45 AM
Glenn also blew the hatch. The only effect this had was slight bruising to two knuckles on his hand caused by the recoil of the plunger. There is no mention of any damage to his space suit. Perhaps Schirra was unlucky.In an emergency situation surely the astronaut would have been prepared to take the risk. |
Robert Pearlman
Editor Posts: 43576
From: Houston, TX
Registered: Nov 1999
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posted 10-30-2010 07:45 AM
quote:
Originally posted by moorouge:
In an emergency situation surely the astronaut would have been prepared to take the risk.
No doubt, but even in the less risk-adverse 60's, I cannot see NASA approving a rescue mission that called for a procedure they knew could rip the suit. |
Skylon
Member Posts: 277
From:
Registered: Sep 2010
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posted 10-30-2010 10:02 AM
Was there anything in a Mercury's cabin an astronaut could use to strike the plunger with, instead of directly with their hand (a checklist, a camera while holding it by the lens)? |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 10-30-2010 10:02 AM
NASA knew only that on one flight was a glove ripped by blowing the hatch. They would also know that on another flight the glove wasn't ripped. Hardly enough evidence to say it wouldn't be sanctioned in an emergency. With a Mercury astronaut stranded in space and no rescue effort his survival prospect was nil. At least blowing the hatch with a 50% chance of success and the possibility of transferring to a Gemini makes a better bet.One thing more - where does it say the Mercury gloves had a metal layer? The description of them does not mention it, only that they were of a ribbed construction. Gloves had fingers constructed of a special curved, ribbed material that enabled the astronaut to grip the controls, except for the left middle finger, which was made of pressurized material that let the astronaut more easily push buttons. The first finger of each hand had a small light built in, to help the astronaut see the control panel. On edit - Shepard also blew the hatch on recovery with no reported damage. The odds now 66% of success. Can't remember whether Cooper did. |
Robert Pearlman
Editor Posts: 43576
From: Houston, TX
Registered: Nov 1999
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posted 10-30-2010 10:47 AM
NASA, even in the 60's, didn't leave critical systems to chance in its (contingency) planning. The solution might have been as simple as what was suggested above: locating another object in the cabin that could be used to strike the plunger (though the forces imparted through that item might still result in injury to the astronaut). If that wasn't possible, my bet would be they would rule out blowing the hatch from inside and seek the means to open it from outside. The Smithsonian identifies the materials in the construction of the Mercury gloves: - Glove Exterior: Neoprene-Coated Nylon, heat resistant textiles, steel, polyester, Brass, Aluminized Nylon
- Glove Interior: rubber, steel, Neoprene-Coated Nylon, Latex
- Wrist Disconnect: Anodized aluminum, Rubber (Silicone)
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