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Author
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Topic: Gemini spacecraft adapter section differences
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LM-12
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 03-15-2012 05:03 PM
  
Compare Gemini 7 photo S65-63220 with Gemini 9A photo S66-38050. Does anyone know why the adapter sections look so different? |
space1
Member Posts: 861
From: Danville, Ohio
Registered: Dec 2002
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posted 03-15-2012 05:28 PM
The Gemini 8-12 adapters were designed for EVA access. The central area of the adapter cover was recessed to enclose the Astronaut Maneuvering Unit (AMU) or other experiments. Handholds and foot holds were also added. |
LM-12
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 03-15-2012 05:55 PM
The Gemini 7 adapter has a rib-like surface and the Gemini 9A adapter looks smooth in comparison. |
space1
Member Posts: 861
From: Danville, Ohio
Registered: Dec 2002
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posted 03-15-2012 07:06 PM
Okay, I answered without looking at the photos. The Gemini 7 adapter has black stripes to reduce the effective radiator area, since it was found in testing that the environmental control system cooled the spacecraft too much. Gemini 8-12 replaced these stripes with black patches of Velcro. These reduced the effective radiator area while also giving the EVA astronaut an opportunity to grip the spacecraft surface (while using handholds with mating Velcro patches). The actual adapter surfaces are identical. |
LM-12
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 03-15-2012 07:19 PM
Interesting. Thanks for that explanation. |
Jay Chladek
Member Posts: 2272
From: Bellevue, NE, USA
Registered: Aug 2007
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posted 03-15-2012 07:52 PM
As John has already answered, technically, the surface of all the adapters were smooth. What many interpret to be "ribbing" is actually black stripe tape.Dragon for instance interpreted the stripes as ribbed recesses on their pre-built models and their kits when they aren't. Although technically the velcro squares would have a little surface relief to them. I would be curious to know if Gemini 10, 11 and 12 for certain had the velcro squares though since Cernan said they weren't entirely effective when used by themselves since his inertia tended to pop him off anyway if he made abrupt moves. For Gemini 10 and 11, I believe the spacewalkers had access to the Gemini 4 gas gun for mobility, but I don't recall for certain if they had a requirement to spacewalk to the back of the Gemini's adapter section. Gemini 9, of course, had the AMU which is why Cernan had to get back there (hence the velcro). Gemini 12 had the rear worksite station with the foot restraint, so Aldrin had to travel to the back as well. Gemini 12 was also originally intended to carry the AMU for a re-flight attempt, but the decision was made to ultimately not fly it. |
LM-12
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 03-15-2012 08:05 PM
It looks like the Gemini 11 adapter had the velcro squares, as can be seen in NASA photo S66-47635. |
Rusty B
Member Posts: 239
From: Sacramento, CA
Registered: Oct 2004
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posted 03-16-2012 11:25 AM
The Gemini adapters had radiator cooling tubes run along the ribs of the adapter internally, from fore to aft, according to diagrams I've seen in a document on the Scribd document server. The black stripes seem to be over that area. Maybe the black stripes were added as a means (or test) of thermal control?The small, square, rounded edge, black patches on the adapter section, are velcro patches used during EVA missions. The Gemini adapter cooling diagrams are in these manuals: |
LM-12
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 03-29-2012 12:52 AM
Here is a diagram of the Gemini spacecraft that shows the location of the coolant radiators in the adapter sections. |
Jay Chladek
Member Posts: 2272
From: Bellevue, NE, USA
Registered: Aug 2007
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posted 03-29-2012 03:22 AM
quote:
Originally posted by Rusty B:
Maybe the black stripes were added as a means (or test) of thermal control?
Yes, the black stripe tape was indeed a means of thermal control. Given that coolant tubes run underneath them, the location of the tape makes sense. Apparently there was some concern that having an all white service module would cause internal systems inside to cool down too much either in shade or on a night pass. Since black retains heat better, that is why the tape was added. As I recall, it was similar reasoning to why black stripes were added to the orbital Mercury capsule retropacks as well.Now I don't know why they went away from the stripe tape on the later flights, but considering the velcro patches are also black in color, it is likely they would serve a similar function for thermal control, so NASA ended up trying to kill two birds with one stone. Or it could also be that Gemini 7's 14 day flight gave them enough data to show the service module held up just fine and the tape was considered redundant by that point. |
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