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Author
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Topic: Skylab workshop airlock module: Gemini hatch
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Headshot
Member Posts: 891
From: Vancouver, WA, USA
Registered: Feb 2012
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posted 06-01-2013 02:26 PM
   
Does anyone know if the exit hatch on Skylab's airlock module, that permitted the astronauts to go EVA, was actually a spare Gemini hatch? It certainly looks like one on page 203 of NASA SP-4208, Living and Working In Space - A History of Skylab. I know that McDonnell built Gemini and McDonnell-Douglas built the airlock module.Has anyone seen any better pictures of Skylab's EVA hatch? |
Tom
Member Posts: 1610
From: New York
Registered: Nov 2000
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posted 06-01-2013 02:41 PM
Here's a closeup view of one on the back-up Skylab airlock. |
Fra Mauro
Member Posts: 1624
From: Bethpage, N.Y.
Registered: Jul 2002
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posted 06-01-2013 02:44 PM
From what I have read, I'm almost certain that it isn't a spare Gemini hatch but instead a hatch based on that design. There is a great photo on the history section of the NASA website. |
mode1charlie
Member Posts: 1184
From: Honolulu, HI
Registered: Sep 2010
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posted 06-01-2013 02:46 PM
Interesting that this subject should come up now. I was just at Spacefest, and brought with me a Skylab poster (the one with the cutaway showing astronauts floating inside the modules) to be signed by Bean, Lousma, and Gibson. Lousma was particularly keen to pore over the image, and pointed out for me among other things, the Gemini hatch. I'd never heard this before, but yes, it was basically that. He referred to it as a "Gemini hatch". Whether it was a spare, a modified spare, or a hatch based on the Gemini design I don't know, but it was one of the three. On edit: someone posted the photo after I started writing my original post, and from the looks of it I'd guess it was one based on the original Gemini design rather than a spare, but not sure. |
Robert Pearlman
Editor Posts: 43576
From: Houston, TX
Registered: Nov 1999
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posted 06-01-2013 02:52 PM
Relevant: Photo of the week 374 (December 25, 2011) |
Jim Behling
Member Posts: 1488
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 06-01-2013 03:03 PM
Various Skylab documentation says it is a Gemini hatch. The airlock module was built in St Louis at the McDonnell plant. The window is a dead give away that it is an actual Gemini hatch. A hatch "based on" the Gemini would have this designed out. |
Jay Chladek
Member Posts: 2272
From: Bellevue, NE, USA
Registered: Aug 2007
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posted 06-01-2013 11:12 PM
It was a Gemini hatch. It underwent some minor modifications, but it was indeed a Gemini hatch.AAP was under a mandate to use off the shelf technology where they could and some of the engineers lamented that the mandate didn't necessarily speed up their development time or save money as sometimes it can take longer to design a system when you have to use hand me downs as opposed to designing an all new piece of equipment to do a certain job. And longer development tends to lead to cost overruns. |
tetrox
Member Posts: 142
From: London England
Registered: Jan 2008
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posted 06-02-2013 12:36 PM
In the MSFC "Airlock module final report" it states: The Gemini hatch used for EVA egress and ingress incorporated a window in the initial design.This window served no functional purpose in the airlock however it was retained to eliminate making a design change. It goes on to say that a teflon cover was put over the window prior to launch and during SL2 activation a metal cover was put over the inner pane. |
mikej
Member Posts: 481
From: Germantown, WI USA
Registered: Jan 2004
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posted 06-03-2013 06:15 PM
I you scroll down to page [9] of Skylab, Classroom in Space, it points out: This hatch was the same as that used on the Gemini spacecraft. In 1965, Astronaut Edward White had exited through one like it on Gemini 4 to become the first American to walk in space. The hatch had been well tested and proven in space. It was selected because of the predominant design philosophy of Skylab, which was to use, as much as possible, equipment that had proven itself in the environment of space. Similarly, Figure 81 of Skylab: A Guidebook calls out the "EVA Hatch (Gemini)". |
kr4mula
Member Posts: 642
From: Cinci, OH
Registered: Mar 2006
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posted 06-04-2013 12:54 PM
So was this truly a "recycled" hatch leftover from Gemini, or newly manufactured from the Gemini specs? |
Headshot
Member Posts: 891
From: Vancouver, WA, USA
Registered: Feb 2012
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posted 06-04-2013 03:27 PM
This will be very difficult to nail down, unless some of the original McDonnell engineers/technicians involved with the airlock module read cS and wish to add their two cents.McDonnell almost certainly had a spare set of Gemini hatches either: (1) in inventory (for emergency replacement during the Gemini Program) or (2) on a high-fidelity mock-up. Remember that NASA chose McDonnell to supply the airlock module in August 1966 (while Gemini was still flying) with the caveat that they would use as much off the shelf Gemini hardware as possible. An existing set of hatches would certainly help. But, McDonnell probably had not dismantled the Gemini spacecraft manufacturing line at that time of being chosen to manufacture the airlock adapter because they hoped to supply additional Gemini re-entry modules to the Air Force for their MOL program, which was not cancelled until 1969. So McDonnell still had the capability of easily manufacturing Gemini hatches. On a different tack, can any cS'er verify that each of the 11 flown Gemini re-entry modules have both hatches? |
onesmallstep
Member Posts: 1313
From: Staten Island, New York USA
Registered: Nov 2007
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posted 06-04-2013 03:50 PM
Do you mean the 12 flown Gemini capsules (two unmanned, 10 manned) plus the sole unmanned Blue Gemini/MOL capsule flown aboard a Titan III? I know a previous thread addressed the issue of hatches separated from their spacecraft. |
Headshot
Member Posts: 891
From: Vancouver, WA, USA
Registered: Feb 2012
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posted 06-04-2013 05:01 PM
Eleven Gemini returned to Earth. Ten manned (Gemini 3-12) and one unmanned (Gemini 2 which was also re-used as the MOL test article). The boilerplate spacecraft used for Gemini 1 did not survive re-entry. |
mikej
Member Posts: 481
From: Germantown, WI USA
Registered: Jan 2004
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posted 06-04-2013 06:14 PM
quote:
Originally posted by Headshot:
On a different tack, can any cS'er verify that each of the 11 flown Gemini re-entry modules have both hatches?
I can verify that very few have both hatches:
- Gemini 2: Displayed with no hatches
- Gemini 3: Displayed with one attached hatch and one hatch nearby
- Gemini 4: Displayed at the National Air and Space Museum with one attached hatch. The other hatch is displayed at the Cradle of Aviation on Long Island
- Gemini 5: Displayed with one attached hatch
- Gemini 6: Displayed with one attached hatch
- Gemini 7: Displayed with no hatches
- Gemini 8: Displayed with one attached hatch
- Gemini 9: Displayed with no hatches
- Gemini 10: Displayed with no attached hatches, but one nearby
- Gemini 12: Displayed with one attached hatch
I have not see Gemini 11, but the Field Guide shows it displayed with only one hatch. |
Headshot
Member Posts: 891
From: Vancouver, WA, USA
Registered: Feb 2012
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posted 06-04-2013 06:54 PM
Thanks Mike. That list is very interesting.Comparing it to the National Air and Space Museum's inventory list of human spaceflight artifacts, which lists several Gemini hatches, we cannot determine the location of the following Gemini hatches: - Gemini 2 - 2
- Gemini 5 - 1
- Gemini 6 - 1
- Gemini 8 - 1
- Gemini 9 - 1
- Gemini 12 - 1
So there are three potential sources for the EVA hatch on Skylab's airlock module: - A reused/refurbished flown Gemini hatch.
- A spare unflown Gemini hatch.
- A hatch manufactured by McDonnell specifically for the airlock.
This gets worse the deeper we dig into it.Given the number of unaccounted, flown Gemini hatches, I would have to guess that No. 1 is the most viable, practical and financially desirable source from NASA's point of view. Any other votes? |
Robert Pearlman
Editor Posts: 43576
From: Houston, TX
Registered: Nov 1999
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posted 06-04-2013 07:00 PM
I've seen it suggested, though not substantiated, that the hatch was already manufactured for MOL and was just re-purposed after that program was shut down.NASA transferred the Gemini spacecraft to the Smithsonian in 1967 and 1968. Barring information to the contrary, I would assume the flown hatches were no longer available by the time McDonnell would go looking for one for Skylab. |
Jim Behling
Member Posts: 1488
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 08-13-2013 08:31 AM
NASA Technical Memorandum TM X-64810 MSFC Skylab Airlock Module provides some more insight. The AM legacy started with a study for the Spent Stage Experiment Support Module by McDonnell Aircraft in 1965. At that time, it included part of the Gemini Adapter/radiator. 98% of SSESM components were Gemini qualified (must mean non structural components) |
Explorer1
Member Posts: 180
From: Los Angeles, CA, USA
Registered: Apr 2019
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posted 12-21-2019 09:08 AM
On Skylab, I believe there was a door that lead into an airlock that all three astronauts could occupy. And two of the astronauts would then exit a hatch inside the airlock into open space.The door that lead into the airlock was actually a door off a Gemini spacecraft. Does anyone know which Gemini spacecraft the door came from? Editor's note: Threads merged. |
Fra Mauro
Member Posts: 1624
From: Bethpage, N.Y.
Registered: Jul 2002
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posted 12-21-2019 09:39 AM
It was flight-qualified surplus. |
Lou Chinal
Member Posts: 1332
From: Staten Island, NY
Registered: Jun 2007
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posted 12-21-2019 03:44 PM
quote:
Originally posted by mikej:
Gemini 4: Displayed at the National Air and Space Museum with one attached hatch.
Just as a note, the hatch on display at the National Air and Space Museum is the commander's hatch. |
space1
Member Posts: 861
From: Danville, Ohio
Registered: Dec 2002
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posted 12-22-2019 08:08 AM
Note that the Skylab hatch is the design of the Gemini Command Pilot hatch (left side). Also two flight Skylab Workshops were made (the backup is in the National Air and Space Musuem collection), so two flight hatches were used.In a phone conversation many years ago, a McDonnell manager told me that the Skylab Gemini hatch had its own set of drawings (separate from the Gemini number series). This would support the idea of a separate fabrication, but does not prove it one way or the other. |
Jim Behling
Member Posts: 1488
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 12-24-2019 06:25 AM
quote:
Originally posted by Explorer1:
On Skylab, I believe there was a door that lead into an airlock that all three astronauts could occupy.
No, all three would not occupy the airlock, only the two going EVA. The door that led to the outside was a new Gemini door. |
Explorer1
Member Posts: 180
From: Los Angeles, CA, USA
Registered: Apr 2019
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posted 12-28-2019 05:02 PM
When the two astronauts were performing the spacewalk, was the Gemini hatch closed? I was under the impression that all three astronauts suited up and the third astronaut stayed behind to monitor the spacewalk which would suggest that the third astronaut was exposed to the vacuum as well. |
Jim Behling
Member Posts: 1488
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 12-30-2019 10:09 AM
No, the Gemini hatch was the access to the exterior of the station and the EVA umbilicals passed through the opening.It was an airlock. The purpose of the airlock is to isolate itself from the rest of the station and allow the crew to go EVA. There were three hatches on the airlock, which allowed the other station elements (MDA and workshop) to remain pressurized. The third crew person stayed in the MDA, which was still pressurized, to monitor the EVA. This did not trap him and allowed access to the CSM in case of a repress problem.
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Explorer1
Member Posts: 180
From: Los Angeles, CA, USA
Registered: Apr 2019
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posted 12-31-2019 03:34 AM
Okay but did the third astronaut monitoring the spacewalk suit up as well? |
Jim Behling
Member Posts: 1488
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 12-31-2019 09:04 AM
No need as explained above.
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billshap
Member Posts: 17
From: St. Louis, MO, USA
Registered: Nov 2009
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posted 12-31-2019 03:31 PM
Was the third crew member (non-EVA) confined to the Airlock Module, or could he get back into the OWS? |
Jim Behling
Member Posts: 1488
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 01-02-2020 11:46 AM
As stated before, the third crew member was monitoring the EVA in the MDA. No unsuited person could be in the airlock because it was open to the vacuum of space during the whole duration of the EVA. Hence, the OWS was inaccessible to the 3rd crew member. The third crew member did have his suit with him in case of airlock failure and the MDA and/or CSM would have to be depressurized to allow the two EVA members to return. |
billshap
Member Posts: 17
From: St. Louis, MO, USA
Registered: Nov 2009
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posted 01-04-2020 11:41 PM
Thanks for the response. Sorry for my mistake — meant to say the MDA where the third crewmember was during Skylab EVA, not the AM, thinking he might be able to go back into the OWS from the MDA. |
Jim Behling
Member Posts: 1488
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 01-05-2020 10:28 AM
Not possible. The AM is in between the MDA and OWS. That is why he is in the MDA, so that he can not be stranded in the OWS in case of an AM issue. |
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