Gemini-B/MOL and TKS/FGB transfer tunnels: internal hatches or not?

[John Charles]

I hope the experts of NSF have some insights that have eluded me.

The transfer tunnel from the Gemini-B into the living compartment of the MOL was closed at the Gemini-B heat shield end by the heat shield hatches, but does anyone know how it was closed at the MOL end? No hatch is visible in the Spacecraft Films footage of zero-g testing of the MOL mockup in 1966, although considerable attention is devoted to the heat shield hatches. If transfer from Gemini-B to and from MOL was the topic of those tests, then there should have been a simulated hatch at the MOL end--unless no such thing was actually planned.

Why is this important? It speaks to the post-Gemini-B longevity of the MOL. When the Gemini-B separated from MOL for retro-fire, an open tunnel into the MOL would quickly vent all the remaining atmosphere inside the MOL. If the MOL was to remain even minimally functional thereafter--for example, even just to de-orbit itself later--it would first have to stabilize itself from the propulsive effects of atmosphere dumping. But how long could its systems continue to function in vacuum. Obviously, both Gemini and Apollo spacecraft functioned well in vacuum--does anyone know if MOL was designed to do likewise?

Same question for TKS-FGB tunnel. (Not the FGB-Almaz docking mechanism.) Does anyone know whether it was closed at the FGB end?  And, did it use physical compression plus a gasket to seal against the TKS heat shield, as did the MOL tunnel?  And were there two separate hatches at the TKS heat shield (as for the Gemini-B): one for the pressure bulkhead and another to plug the hole in the heat shield?

Thanks to all for your patience with yet another MOL inquiry!

John Charles
Houston, Texas

[John Charles]

Another Gemini-B question (related, so not starting a new thread):

At the end of its 30-day mission, when the Gemini-B was to separate from the MOL, de-orbit and land, was the plan for the whole Gemini-B assemblage (re-entry vehicle, retro module adapter, and equipment adapter) to separate from the MOL, prior to jettisoning the equipment module adapter to permit retro-fire? Or was the equipment module left bolted to the MOL, exposing the retros immediately on separation from the MOL?

Official artwork from 1964-1965 showing the Gemini-B re-entry vehicle separating from the MOL (this picture--if you have only ever seen one MOL picture, it was probably this one) shows no role for the retro module, not to mention a meaningless retro module interior configuration. Was this image just public dis-information?

Thanks for any insights!

John Charles
Houston, Texas

[rdale]

You might also post this on the public side - my guess is most of the info on MOL is not restricted anymore so you could have a better response?

[Jim]

Another Gemini-B question (related, so not starting a new thread):

At the end of its 30-day mission, when the Gemini-B was to separate from the MOL, de-orbit and land, was the plan for the whole Gemini-B assemblage (re-entry vehicle, retro module adapter, and equipment adapter) to separate from the MOL, prior to jettisoning the equipment module adapter to permit retro-fire? Or was the equipment module left bolted to the MOL, exposing the retros immediately on separation from the MOL?

Official artwork from 1964-1965 showing the Gemini-B re-entry vehicle separating from the MOL (this picture--if you have only ever seen one MOL picture, it was probably this one) shows no role for the retro module, not to mention a meaningless retro module interior configuration. Was this image just public dis-information?

Thanks for any insights!

John Charles
Houston, Texas

There was no equipment adapter on MOL Gemini

[Jim]

http://forum.nasaspaceflight.com/index.php?topic=23864.0

Discussion her.

[John Charles]

http://forum.nasaspaceflight.com/index.php?topic=23864.0

Discussion her.

Jim, thanks! I missed that brief mention the first few times I scanned the thread. Glad that someone else noticed the complete absence of a hatch to seal the other end of the Gemini-B/MOL transfer tunnel.

But the question remains: what was to happen at the end of the 30-day mission of the non-reusable MOL?  I wonder if it was vented to vacuum before Gemini-B separation, and if so, what did that mean for subsequent MOL de-orbit operations.

And same questions for TKS/FGB.  I have looked at the Excalibur-Almaz website but not yet found an answer.

John Charles
Houston, Texas

[Jim]

But the question remains: what was to happen at the end of the 30-day mission of the non-reusable MOL?  I wonder if it was vented to vacuum before Gemini-B separation, and if so, what did that mean for subsequent MOL de-orbit operations.

There were two hatches. One on the spacecraft and one in the tunnel

[John Charles]

There were two hatches. One on the spacecraft and one in the tunnel

Where in the tunnel?  It wasn't visible in the Spacecraft Films video.

[Jim]

There were two hatches. One on the spacecraft and one in the tunnel

Where in the tunnel?  It wasn't visible in the Spacecraft Films video.

It is the one the crew folds down into the tunnel and covers with two flaps. 

[simonbp]

WRT the equipment adapter, Gemini B had extra solid retro rockets to account for the extra Delta V from not having a rear RCS. IIRC, the USSRC in Huntsville actually has one of the Gemini retro adapters on storage (or at least did five-or-so years ago, when I saw it)...

[John Charles]

There were two hatches. One on the spacecraft and one in the tunnel

Where in the tunnel?  It wasn't visible in the Spacecraft Films video.

It is the one the crew folds down into the tunnel and covers with two flaps. 

I believe you are referring to the heat shield plug hatch. It plugged the hole in the heat shield.  But that would have left the tunnel open to vacuum after the Gemini-B departed. And if the tunnel did not have another hatch, then the MOL would also have been open to vacuum.

[John Charles]

WRT the equipment adapter, Gemini B had extra solid retro rockets to account for the extra Delta V from not having a rear RCS. IIRC, the USSRC in Huntsville actually has one of the Gemini retro adapters on storage (or at least did five-or-so years ago, when I saw it)...

Right, the retros were in the retro module, but there was also an additional adapter between the retro module and the MOL.

Thanks for the info from Huntsville.  Is that the same one I saw pictures of outside, half-buried in grass?

[simonbp]

Yep. As of a few years ago, they were trying to get a flown Gemini capsule to mate with it and the spare Agena Docking Target vehicle they have sitting in a warehouse on the Arsenal. They never got the Gemini, and so are now focusing restoration efforts on the Syklab 1-g trainer...

[John Charles]

...when the Gemini-B was to separate from the MOL, de-orbit and land, was the plan for the whole Gemini-B assemblage (re-entry vehicle, retro module adapter, and equipment adapter) to separate from the MOL, prior to jettisoning the equipment module adapter to permit retro-fire? Or was the equipment module left bolted to the MOL, exposing the retros immediately on separation from the MOL?

Just for the historical record, the answer is that the Gemini-B would have separated from the MOL at the equipment adapter/MOL interface, and then the adapter would have been jettisoned to expose the retros, just like on NASA Gemini vehicles.  The answer was in a diagram (again courtesy of Dr. Dwayne Day) which showed shaped charges at both the retro/equipment adapter interface and the equipment adapter/MOL interface. In the drawing, the arrow pointing to the latter shaped charge was hard to see the first few dozen times I looked at it.

[Jim]

There is no equipment adapter for a Gemini MOL.

It separated with the retros exposed

[John Charles]

There is no equipment adapter for a Gemini MOL.
It separated with the retros exposed

Jim,
Not that I don't believe you, but these photos indicate otherwise.
The photo of the mockup clearly shows the two components of the Gemini-B adapter(s) aft of the capsule, with the retros yet to be fitted into their locations in the middle component, the retro adapter.
In particular, the line drawing indicates the shaped charges at both interfaces, as mentioned in my earlier message.  I don't know why it would need a shaped charge at the aft end of the outboard adapter (which I've been calling the equipment adapter) if it was not intended to break the 26 bolts holding it to the MOL.

[Capt. David]

Quite a bit late on this reply, but yes - both the Almaz FGB and Orbital Piloted Station (had the station been launched with a manned RRV) each had a separate hatch door which opened inward.

Here is an image from Nicolas Pillet which shows the open hatch located on the front of Almaz № 0205:



Notice the two ring gaskets circling the hatch opening but none on the Hatch Cover. Early test models of the Almaz RRV had similar configuration, but added two gaskets on the Hatch Cover. It is not clear if the Hatch Cover on the Almaz OPS and TKS would have added this modification had either of these been launched manned.

Regards,

David L. Rickman
549 Caribou Road
Asheville, NC  28803
USA

[Prober]

Good video find of the MOL Gemini test model

http://www.youtube.com/watch?NR=1&v=3t3cIGqEM2I&feature=endscreen

[Space Possum]

Here is an ok picture I took a couple of weeks ago on this same tour. Detail of heatshield & hatch section. Sorry for the quality.

[Blackstar]

Here's a less blurry shot.