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Author
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Topic: Mercury pressure suit use during missions
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Jim_Voce
Member Posts: 273
From:
Registered: Jul 2016
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posted 06-27-2018 01:16 AM
   
The Mercury pressure suit had two hose attachments — one that led directly from the astronaut's helmet and the second which was on the lower left abdomen of the suit. Which of these hoses provided the oxygen intake into the astronaut's suit? Was it the helmet hose? And if so, then was the hose that led into the abdomen socket of the suit simply for air cooling?During the launch phase, the astronauts had their helmet visors down. In this mode I assume this means that the astronauts were breathing oxygen completely within the internal environment of their suits and that they were receiving oxygen from the helmet hose that led from the instrument panel of thr spacecraft. Is this correct? And then once in orbit, the astronauts could lift their visors and breathe oxygen that was freely distributed in the cabin of the spacecraft. Is this correct? Was the Mercury cabin fully pressurized at the time of launch such that the astronaut could have gone through launch and ascent with his visor down if he chose to? Since the Mercury (Mark IV) pressure suit was designed for an internal environment can anyone speculate how that suit would have performed if exposed to the full vacuum of space? Would the astronaut have been able to survive for awhile in open space in the Mark IV pressure suit? |
Jim Behling
Member Posts: 1488
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 06-27-2018 06:09 AM
quote:
Originally posted by Jim_Voce:
...simply for air cooling?...from the instrument panel of thr spacecraft. Is this correct? ...distributed in the cabin of the spacecraft. Is this correct? ...with his visor down if he chose to?
Yes. quote:
...open space in the Mark IV pressure suit?
A short while. They would overheat in sun. |
Jim_Voce
Member Posts: 273
From:
Registered: Jul 2016
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posted 06-27-2018 08:49 PM
What modifications would have been needed to "beef" up the Mercury pressure suit so that it could sustain an astronaut in open space? Secondly, if the Mercury pressure suit did not have adequate protection against the extremes of temperature then what would have happened if the spacecraft suffered even a small hull puncture? Such a puncture I presume would have been enough to drop or raise temperatures in the spacecraft considerably. No doubt this would have resulted in an immediate deorbiting of the spacecraft and hoping for the best as far as the astronaut surviving temperature fluctuations. I wonder if it would have been possible to survive reentry (as far as internal temperatures go) with a small hole puncture in the side of the spacecraft? And I presume that even a small puncture in the spacecraft would have let in enough frictional heat into the interior cabin as to burn through a bigger hole and destroy the spacecraft anyway. Also, historically as I recall, the Mercury suits had a tendency to overheat on the orbital missions. But I am not sure if that was a problem with the suit itself or the environmental control system on the spacecraft. And finally, in any readings on the subject of the Mercury suit it is frequently said that the Mercury pressure "suit was only pressurized in the event that the cabin pressure failed." But to clarify this remark, wouldn't it be better to say: "Once in orbit, the Mercury pressure suit was only pressurized in the event that the cabin pressure failed." In other words, the suit as I understand it was always pressured during ascent to orbit and for reentry. Overall then, it sounds like the only benefit that the Mercury pressure suit offered the astronauts was in the event that the environmental control system had an electrical or mechanical failure and stopped producing adequate oxygen and air pressure within the cabin, then the astronauts could close their visors and hope that the same environmental control system would supply them with oxygen directly into their suits. Is this basically correct? |
Jim Behling
Member Posts: 1488
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 06-28-2018 11:18 AM
quote:
Originally posted by Jim_Voce:
What modifications would have been needed...
What would be a Gemini or even better an Apollo EVA suit. Those differences would be needed. quote:
...what would have happened if the spacecraft suffered even a small hull puncture?
It isn't the vacuum that is the issue. There is no sun or deep space on the inside of the spacecraft, so no temperature extremes. quote:
...it was always pressured during ascent to orbit and for reentry.
No, the suit is not pressurized at any time nominally. The only difference is oxygen flow to the helmet. quote:
Is this basically correct?
The suit is for primary protection from hull breaches. If the ECS for the cabin and suit (there are separate circuits) isn't working, then there is an emergency system that just supplies O2 to the suit with no other ECS functions (H2O, CO2, odor, heat, etc. removal). |
oly
Member Posts: 971
From: Perth, Western Australia
Registered: Apr 2015
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posted 06-28-2018 10:38 PM
quote:
Originally posted by Jim_Voce:
Is this basically correct?
No, the suit was incorporated to protect the astronaut from a spacecraft pressure failure. If such a failure occurred, an immediate mission abort would be called. If for any reason an electrical or mechanical failure happened, the risk of fumes in the cabin, fire, system failure or additional faults would be too great.Most of the answers to your questions are found on these sites: ...and also from the reference you cited. |
Philip
Member Posts: 6002
From: Brussels, Belgium
Registered: Jan 2001
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posted 06-29-2018 05:02 AM
Always wondered how they "connected" the shoes to the Mercury space suit... |
Robert Pearlman
Editor Posts: 43576
From: Houston, TX
Registered: Nov 1999
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posted 06-29-2018 05:15 AM
The Mercury boots are discussed in this topic (citing a post by oly): ...the Mercury suit was manufactured with the foot as part of the suit, acting as a bladder with the astronaut contained within the bladder. The boots were relatively standard boots, fitted to contain the bladder inside. |
DaveS
Member Posts: 18
From: New Bedford, MA
Registered: Aug 2017
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posted 06-29-2018 08:38 AM
“We Seven” by the Astronauts has a great chapter on this subject. The chapter titled “Our Cozy Cacoon” by Wally Schirra will answer your questions including how a hull breach would effect the astronaut. |
oly
Member Posts: 971
From: Perth, Western Australia
Registered: Apr 2015
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posted 07-07-2018 04:59 AM
quote:
Originally posted by Jim_Voce:
Also, historically as I recall, the Mercury suits had a tendency to overheat on the orbital missions. But I am not sure if that was a problem with the suit itself or the environmental control system on the spacecraft.
Gordon Cooper reported in his oral history project interview that the temperature control of the Mercury suit was always problematic "We always had trouble keeping the temperature of the suit adjusted, because the valve was so sensitive that, when you went a little too far on it for coolness, you'd tend to freeze it up. You'd have to back off and get it unfrozen." The Mark IV suit received many modifications to become the Mercury suit, including the use of the neck dam, requiring the addition of the helmet Oxygen outlet port. The neck dam allowed the suit to be immersed in water while the helmet visor was open (some Navy mark IV helmets used a faceplate dam design), as seen here. The neck dam had a one way valve that allowed the air to pass from the torso to the helmet, to be removed via the outlet port, via the pressure regulator. |
Space Cadet Carl
Member Posts: 225
From: Lake Orion, Michigan
Registered: Feb 2006
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posted 07-08-2018 11:43 AM
Was that neck dam successful in keeping water out of Grissom's suit, or was he dangerously taking on water before being fished out? |
oly
Member Posts: 971
From: Perth, Western Australia
Registered: Apr 2015
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posted 07-08-2018 09:55 PM
As part of the post landing procedures, Grissom removed his helmet and disconnected the suit hoses. Waiting for the helicopter to arrive and hook onto the capsule, the hatch fired, causing water to begin flooding into the capsule, Grissom dove free from the capsule but did not close the suit valves, allowing water to flood the suit. There was also a rubber diaphragm that could be stretched over the neck ring, similar to a kayak skirt. Grissom did not have time to install this. An image of this can be found in this Ars Technica article. |
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