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Author
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Topic: Mercury spacesuit neck dam configuration
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Explorer1
Member Posts: 88
From: Los Angeles, CA, USA
Registered: Apr 2019
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posted 11-10-2019 11:20 PM
   
The Mercury spacesuit neck ring was fitted with a water blocking neck dam that the astronaut could pull closed over his neck in the event that the astronaut had to jump in the ocean during spacecraft recovery. Does anyone know how the neck dam was worn or accessed? The first picture shows the neck ring and fabric interior of Scott Carpenter's suit with no visible trace of a neck dam stored or retracted within the dimensions of the neck ring. And the second picture shows Carpenter during water recovery training adjusting a neck dam. This makes me wonder if the neck dam was pulled over the head or whether it was in a retracted position and then pulled into place to surround the neck. When Gus Grissom had to jump in the ocean as his Mercury capsule was sinking, he was able to pull into place a neck dam. So it remains unclear to me how the neck dam was accessed. Was the neck dam stored in a pocket on the Mercury suit and taken out when needed?  
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DG27
Member Posts: 173
From: USA
Registered: Nov 2010
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posted 11-11-2019 04:01 PM
The first picture does in fact show the neck dam in its stowed position on the outside of the neckring with its protective cover in place. |
Explorer1
Member Posts: 88
From: Los Angeles, CA, USA
Registered: Apr 2019
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posted 11-12-2019 02:29 PM
I am not seeing what you are seeing. Can you point out on the first photograph where the neck dam is stored or what color the protective cover is?I see below the neck ring two yellow packets behind the mirror mounted on Carpenter's chest. The first yellow packet I believe is a life raft and the second packet that has a 'U' shape I believe is a life preserver that goes around the chest and under the astronaut's arms. And in the second photograph, Carpenter has released both packets and has the life preserver inflated and underneath his arms. Or am I mistaken about that and the yellow packets only contain the life preserver and a life raft is carried separately. The life preserver was added to the Mercury suits after Grissom's water recovery experience. But as I recall, Grissom did have a neck dam on his suit. |
PeterO
Member Posts: 399
From: North Carolina
Registered: Mar 2002
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posted 11-12-2019 03:35 PM
In the color photo, I think the silver tab and tube just to the right of the NASA patch is the beginning of the stowed neck dam, which wraps around the outside of the helmet ring below its lip. In the b/w photo the helmet ring is dark after the dam has been deployed.This photo also shows the stowed neck dam. I could be wrong though.  |
Robert Pearlman
Editor Posts: 42981
From: Houston, TX
Registered: Nov 1999
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posted 11-12-2019 04:17 PM
From heroicrelics.org: A conical rubber neck dam was attached to the torso neck ring. The purpose of this neck dam was to prevent water from entering the suit in event of water egress with the helmet off. When preparing to egress the spacecraft, the astronaut would unfasten the helmet from the suit and roll up the neck dam.The rubber diaphragm was fastened on the exterior of the suit, below the helmet attaching ring. After the helmet was disconnected, the neck dam would be rolled around the ring and up around the neck, similar to a turtle-neck sweater, until it provided a seal around the neck.  |
oly
Member Posts: 905
From: Perth, Western Australia
Registered: Apr 2015
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posted 11-12-2019 07:47 PM
It may be possible that the neck dam was fitted during suit up. The MR-4 post-flight report identifies that Gus Grissom was wearing the neck dam during the mission, inferring that the dam was donned during suit up, prior to the donning of the helmet.This report also details the Grissom "rolled the neck dam into position over the suit neck ring" prior to disconnecting his spacesuit connectors. This article from Ars Technica details "nor had he unfurled a dam that rolled around the neck like a turtleneck sweater in order to form a seal," so there may be some ambiguity in the details. Perhaps this could be confirmed by scouring records and images of pre-launch suit donning or capsule ingress. Images of Shepard during helicopter winch recovery do not show the neck dam deployed, while Grissom can be seen in post-landing photos with the dam deployed. I would think that the dam would be uncomfortable, and something that was last to be installed and first to be removed, and not worn during photo shoots. There is also the possibility of a procedural change after Grissom's experience. Gemini astronauts stowed the dam in a suit pocket "In addition to the life vests, a neck dam is stowed in a suit pocket. Before entering the water from the spacecraft, the astronaut removes his helmet and dons the neck dam to make a seal around the suit neck ring and his neck. This prevents the suit from filling with water and traps gas within the suit torso to provide additional buoyancy." Apollo suits also had a neck dam that was donned as per the Gemini design. Shuttle crew wearing the ACES suit had the neck dam installed during suit up, perhaps as a part of the neck ring assembly. The incorporated design was introduced to negate the astronaut needing to deal with the dam during water rescue operations, as past experience had revealed the possibility of the crew being unconscious and unable to deploy the dam. Many images exist of Shuttle crew in suits with the special neck dam clips installed to relieve the neck dam pressure on the neck. |
DG27
Member Posts: 173
From: USA
Registered: Nov 2010
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posted 11-13-2019 01:42 AM
As Robert identified in his post, the Mercury suit neck dam was attached to the outside of the neck ring in the flat area just below the rotating latch ring. It was rolled-up/folded-up and covered with a narrow strip of aluminized suit fabric with the ends secured together by a snap. You can see the end of the fabric strip and the securing snap in the first photo (center of the front of the neck ring just above the yellow life preserver pouch).The neck dam was part of the flight-ready pressure suit, so it was not "donned" separately. It was deployed when needed and would be virtually impossible to roll back up once deployed, especially with the suit on. MR-4 mission photos clearly show Grissom deployed the neck dam. His suit was most likely swamped by water entering thru the abdomen oxygen hose attachment port. The early suits had a outer hinged flap/door that was secured once the hose was disconnected. Later suits had an internal self closing valve that automatically sealed when the hose was disconnected. in reference the Shuttle ACES suits, the neck dam you see in photos was not for water intrusion prevention but was the neck-seal separation between the head cavity of pure oxygen and the suit torso of vent air. The ACES neck dam has two one way valves to pass exhaled gas into the suit torso from the head cavity. Water would also pass thru those valves into the suit torso. Shuttle emergency procedures required the torso harness with LPU to stay connected at all times for flotation and the helmet was to stay on for head protection during rescue operations, so there was no opportunity or need to install a water seal over the ACES neck ring.
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Explorer1
Member Posts: 88
From: Los Angeles, CA, USA
Registered: Apr 2019
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posted 11-13-2019 11:39 AM
I have a related question which is after Grissom's flight, astronauts on all the remaining Mercury missions wore a yellow packet on their chest that was positioned behind the mirror (see first picture in this post). When deployed did this yellow packet release a life raft or a 'U' shaped life preserver that fitted under the astronaut's arms? In the first picture in this posting, one can see the 'U' shaped life preserver stored on Carpenter's chest. What struck me about this is this is the first picture I have seen of the 'U' shaped life preserver exposed on an astronaut's chest while it is still in a stowed position. With all other Mercury astronauts I have just seen the yellow packet neatly stowed and mounted on their chests without any indication that there is a 'U' shaped life preserver as well. Also, does anyone know how the mirror and yellow packet were mounted/secured on the chest? Thank you. |
DG27
Member Posts: 173
From: USA
Registered: Nov 2010
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posted 11-13-2019 01:33 PM
The answers to your questions are in the second photo you posted. It clearly shows the life preserver deployed, the opened containment pouch, and the back side of the mirror with retaining clips. It is a good photo. |
Explorer1
Member Posts: 88
From: Los Angeles, CA, USA
Registered: Apr 2019
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posted 11-13-2019 05:24 PM
Okay so the last question for clarification I have is, was the yellow packet that was worn on the chest of the Mercury astronauts, was it the 'U' shaped life preserver or was it a small life raft? I am curious to know if two forms of flotation were mounted to the astronaut's chest or just one. If it was just one, I would presume that it was the 'U' shaped preserver and that the inflatable life raft was stored and accessed separately from the 'U' shaped preserver. But if two forms of flotation were mounted on the chest, then were both forms contained in the yellow packet or were they separately mounted pieces. |
Explorer1
Member Posts: 88
From: Los Angeles, CA, USA
Registered: Apr 2019
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posted 11-13-2019 05:32 PM
Also, I have a picture that shows Grissom in water survival training and he is wearing a traditional life vest and is floating in a life raft. I imagine these two pieces of survival gear were originally stored in the astronaut's survival pack but after Grissom's mission, they eliminated the traditional life vest and replaced it with chest-mounted 'U' shaped life preserver. So the only question is about the life raft and how it was stored on missions after Grissom's. I was under the impression that the chest-mounted yellow packet was the life raft itself in compact form. What threw me was the presence of the 'U' shaped life preserver seen in the Carpenter pictures. That raises the question of which flotation device is the yellow packet — a preserver or a life raft? Or are both stored together as part of the same packet or separately? |
Robert Pearlman
Editor Posts: 42981
From: Houston, TX
Registered: Nov 1999
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posted 11-13-2019 06:05 PM
The life vest (or preserver) was mounted on the chest. The life raft was part of a separate survival kit stowed in the spacecraft, which also included a pocket knife, signaling mirror, shark repellent, seawater desalting tablets, sunscreen, soap, and first aid kit. |
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