I have just been watching an interesting video of a gathering of astronauts. On May 8, 1997, Wally Schirra, Jim Lovell, Alan Shepard, Gene Cernan, and Neil Armstrong gathered to make an historic public appearance at the National Museum of Naval Aviation, emceed by Roy Neal.
In reflecting back on his near-disasterous EVA on Gemini IX, Cernan had this interesting comment on what might have been:
Cernan: "Tom Stafford told me that had the Gemini IX accident not occurred, and had the Russian program accelerated to the point that they might orbit the Moon, it was possible that Gemini XII could have jumped on top of an Agena with a little extra boost, and they would have shot us around the Moon back in 1966. Now, I’m sort of glad things happened the way they did in retrospect, but that really would have been an eye-opener at the time. I’m not sure we could have pulled that one off."
Roy Neal: "Alan [Shepard], you were very instrumental in running the Astronaut office at that time. Can you confirm or deny the report that Cernan has just given us about Gemini XII?"
Shepard: (laughs) "Actually, I would have no comment on that." (laughs) "If you think it’s hard to say ‘no comment,’ it is difficult!"
I find this hard to believe! Would the Gemini heatshield have stood up to a 25,000 mph re-entry?
Full Version: Gemini Xii To The Moon?
Well, I've done some research...probably should have done it before posting above - but I had no idea that Gemini had been explored as a lunar flyby, lunar lander, even a lunar rescue vehicle.
For those interested, see By Gemini to the Moon!
For those interested, see By Gemini to the Moon!
QUOTE (ilbasso @ Feb 12 2006, 08:46 PM) 
Well, I've done some research...probably should have done it before posting above - but I had no idea that Gemini had been explored as a lunar flyby, lunar lander, even a lunar rescue vehicle.
For those interested, see By Gemini to the Moon!
For those interested, see By Gemini to the Moon!
Yes, Gemini was the darling of the engineers - Big Gemini, SASSTO, Lunar Gemini, Blue Gemini...
...and the astronauts liked Gemini, too - Pete Conrad was one of the guys pushing hard for a Lunar Gemini flight (with a double Titan Transtage rather than an agena).
Bob Shaw
There were several lunar Gemini proposals, but likely none of them would have been Gemini XII. The one that was talked about most, I believe, was using a Centaur as a TLI booster (fit a docking collar on it from the Agena TDA assembly and put in a manual control system) for a lunar flyby. The Titan double transstage concept was for a lunar-orbit flight, IIRC.
If we had decided to put a Gemini out around the Moon, it likely would have been Geminis XIII and XIV. And it's likely it would have been circumlunar only, not lunar orbital.
What eventually happened was MSC got really jittery about sending a Gemini so far away from home. While the Gemini had matured by the end of the program, every spacecraft had its share of little glitches, and overall it was a somewhat more fragile spacecraft than Apollo. And, of course, it wasn't designed for a lunar re-entry (though a beefed-up heatshield probably would have handled it fine). They just decided that they already had a spacecraft in the works that was *designed* to go to the Moon, and that it made more sense to get Apollo ready to fly than to divert resources away from Apollo to toss a Gemini (that was *not* designed for such a trip) out there...
-the other Doug
If we had decided to put a Gemini out around the Moon, it likely would have been Geminis XIII and XIV. And it's likely it would have been circumlunar only, not lunar orbital.
What eventually happened was MSC got really jittery about sending a Gemini so far away from home. While the Gemini had matured by the end of the program, every spacecraft had its share of little glitches, and overall it was a somewhat more fragile spacecraft than Apollo. And, of course, it wasn't designed for a lunar re-entry (though a beefed-up heatshield probably would have handled it fine). They just decided that they already had a spacecraft in the works that was *designed* to go to the Moon, and that it made more sense to get Apollo ready to fly than to divert resources away from Apollo to toss a Gemini (that was *not* designed for such a trip) out there...
-the other Doug
It would also have been a nearly pure stunt effort, wasting time and money on a dead-end spacecraft, much as the Soviets wasted time and effort on Voskhod to fly 3 men in space and do an EVA to keep scooping space records, while Soyuz was having a troubled development en route to a catastropic first manned mission.
Direct Flight Apollo Study - Volume 2: Gemini Spacecraft Applications
http://ntrs.nasa.gov/archive/nasa/casi.ntr..._1978072529.pdf
Direct Flight Apollo Study, Report No. 9182, Vol. 1, Two Man Apollo Spacecraft; Vol. 2,
Gemini Spacecraft Applications; Vol. 3, Rescue Versions; McDonnell Aircraft Corporation,
October 31, 1962.
http://www.marsinstitute.info/rd/faculty/d...rtr/ap10-1.html
And don't forget the 1968 film Countdown, which had a modified Gemini land on the Moon
with a single astronaut to beat the Soviets. Based on Hank Searles' novel, The Pilgrim Project:
http://www.imdb.com/title/tt0062827/
http://www.2001exhibit.org/science/timeline_alt8.html
It would have been cool to see a Gemini do that, overlap with Apollo or not.
http://ntrs.nasa.gov/archive/nasa/casi.ntr..._1978072529.pdf
Direct Flight Apollo Study, Report No. 9182, Vol. 1, Two Man Apollo Spacecraft; Vol. 2,
Gemini Spacecraft Applications; Vol. 3, Rescue Versions; McDonnell Aircraft Corporation,
October 31, 1962.
http://www.marsinstitute.info/rd/faculty/d...rtr/ap10-1.html
And don't forget the 1968 film Countdown, which had a modified Gemini land on the Moon
with a single astronaut to beat the Soviets. Based on Hank Searles' novel, The Pilgrim Project:
http://www.imdb.com/title/tt0062827/
http://www.2001exhibit.org/science/timeline_alt8.html
It would have been cool to see a Gemini do that, overlap with Apollo or not.
That movie, believe it or not, was directed by Robert Altman, back before he did "MASH" and became a Big Figure in Hollywood.
"Marooned was a well made "B" movie, hindered by being made about 8 years too late and straight-jacketing the story line of the original Mercury-accident novel into a Apollo-CSM-Accident scenario that was decidedly forced to fit the pre-existing narrative as well as it could.
A RL skylab mission running into trouble and unable to deorbit with a SPS burn would have 1) deorbited with the RCS thrusters (I'm pretty sure that was a mission safety requirement capability) or 2) redocked with the skylab and waited for possible rescue. D'oh.... Didn't fit the jiggered plot.
It still was a decent movie, lightyears beyond lamentably silly "skiffy" movies like "Silent Running", despite the wonderful droids in that one.
A RL skylab mission running into trouble and unable to deorbit with a SPS burn would have 1) deorbited with the RCS thrusters (I'm pretty sure that was a mission safety requirement capability) or 2) redocked with the skylab and waited for possible rescue. D'oh.... Didn't fit the jiggered plot.
It still was a decent movie, lightyears beyond lamentably silly "skiffy" movies like "Silent Running", despite the wonderful droids in that one.
This thread should really be moved either to the "Moon" or "Manned Spaceflight" sections -- but in any case my first 2006 issue of "Quest" (the Univ. of North Dakota's magazine on space history) features a very nicely detailed interview with Gemini program manager Charles W. Mathews, which provides more on the Gemini lunar proposal:
"INTERVIEWER: What kind of work was done looking at the Gemini spacecraft for an early lunar orbital mission or a rescue contingency? How much support did it receive within the GPO and NASA management"
"MATHEWS: I know that it was at least looked at twice, although I was not privy to the first look since it was before my time. That was a very brief look, apparently by NASA HQ. Headquarters tended to look at a lot of things that were kind of far out in terms of possibilities. These notions were frequently chopped off rather early. That's my understanding of what happened. The first look was from the point of view of, if Apollo didn't really come along properly, then how about using Gemini to go to the Moon?
"There was a little more dedicated look at it late in the Gemini Program. It was in the summer of 1966.
"INTERVIEWER: It was referred to as the Large Earth Orbit (LEO) program. It centered on using a Gemini-type spacecraft and an Agena to accomplish a lunar orbital mission. Pete Conrad was a big supporter of it before his Gemini 11 mission.
"MATHEWS: Right. Most of the work that was done focused on the spacecraft, as to whether we could reenter it from lunar return velocities. We found that we could do it, although it would require modifications to the spacecraft. In particular, the aftbody would have to be modified. But it looked good enough that we could do it. I can't remember the exact details, but it was probably using a Saturn 1 or a Saturn 1B with an Agena on top. It would have been a 3-stage system. I don't think the Titan 2 and Agena stages could have hacked it by itself.
"We decided to bring this up at a dinner that Robert Gilruth gave down at his home when Jim Webb was visiting. We had Conrad give the presentation. Webb imediately put his foot down, and he said, 'Absolutely not!' He was probably right, because you don't want a situation where people are confused about what they're doing. He didn't want a situation where one flight program was extending into the other. Your flight control people are probably not up to doing both types of mission. So that was the end of the LEO program."
I'll add only that a Titan 2-Agena could most emphatically not have launched a Gemini to escape velocity -- that combination was actually the "Titan 3B" used in the 1960s and 1970s to launch a whole bunch of mid-sized recon satellites.
"INTERVIEWER: What kind of work was done looking at the Gemini spacecraft for an early lunar orbital mission or a rescue contingency? How much support did it receive within the GPO and NASA management"
"MATHEWS: I know that it was at least looked at twice, although I was not privy to the first look since it was before my time. That was a very brief look, apparently by NASA HQ. Headquarters tended to look at a lot of things that were kind of far out in terms of possibilities. These notions were frequently chopped off rather early. That's my understanding of what happened. The first look was from the point of view of, if Apollo didn't really come along properly, then how about using Gemini to go to the Moon?
"There was a little more dedicated look at it late in the Gemini Program. It was in the summer of 1966.
"INTERVIEWER: It was referred to as the Large Earth Orbit (LEO) program. It centered on using a Gemini-type spacecraft and an Agena to accomplish a lunar orbital mission. Pete Conrad was a big supporter of it before his Gemini 11 mission.
"MATHEWS: Right. Most of the work that was done focused on the spacecraft, as to whether we could reenter it from lunar return velocities. We found that we could do it, although it would require modifications to the spacecraft. In particular, the aftbody would have to be modified. But it looked good enough that we could do it. I can't remember the exact details, but it was probably using a Saturn 1 or a Saturn 1B with an Agena on top. It would have been a 3-stage system. I don't think the Titan 2 and Agena stages could have hacked it by itself.
"We decided to bring this up at a dinner that Robert Gilruth gave down at his home when Jim Webb was visiting. We had Conrad give the presentation. Webb imediately put his foot down, and he said, 'Absolutely not!' He was probably right, because you don't want a situation where people are confused about what they're doing. He didn't want a situation where one flight program was extending into the other. Your flight control people are probably not up to doing both types of mission. So that was the end of the LEO program."
I'll add only that a Titan 2-Agena could most emphatically not have launched a Gemini to escape velocity -- that combination was actually the "Titan 3B" used in the 1960s and 1970s to launch a whole bunch of mid-sized recon satellites.
The Blue Gemini blues
---
In the early 1960s the US Air Force made several attempts to develop
its own manned spaceflight program. Dwayne Day reviews the history
of one of those ultimately unsuccessful efforts, Blue Gemini.
http://www.thespacereview.com/article/582/1
---
In the early 1960s the US Air Force made several attempts to develop
its own manned spaceflight program. Dwayne Day reviews the history
of one of those ultimately unsuccessful efforts, Blue Gemini.
http://www.thespacereview.com/article/582/1
You know, everyone involved in the Gemini program seemed to love that spacecraft -- including but not limited to the guys who flew it.
But Gemini showed a pretty large maturation curve during its manned flights. There were lessons learned during Mercury that took a while to incorporate into Gemini, not the least of which were manufacturing lessons. And if it seemed to take a while for McDonnell-Douglas to learn from its own mistakes, think of how much harder it was for North American Aviation to learn anything from Gemini as it designed and built Apollo.
However, there is an element of heightened danger in flying a Gemini spacecraft that far from home that I think most people underestimate. While Gemini was a much safer spacecraft to fly by the end of the program than it was at the beginning, it suffered from a far higher malfunction rate than the Apollo flights eventually logged.
For example, one reason NASA didn't attempt flights longer than three or four days after the Gemini V and Gemini VII marathons was that a majority of the attitude control system thrusters had failed by the time each of those long-duration flights concluded. On Gemini V, in fact, the thrusters were in such bad shape that the crew was told the activate the re-entry control system two orbits prior to retrofire, to ensure positive control when setting up retrofire attitude.
The Gemini fuel cell system was notoriously finnicky, and always seemed to totter on the brink of reliability without actually achieving it. They didn't produce potable water, either -- the water those cells produced was full of an organic sludge euphemistically called the "brown fuzzies" by the engineers. If the cells put out too much water (as happened on one flight), you had a serious problem, since the nasty fuel cell water was used to pressurize the potable water tank. On a lunar flyby, such a problem could lead to a waterlogged outbound crew and a really thirsty inbound crew... not to mention the need to perturb the outbound trajectory frequently with "Constellation Urion".
Finally, the Gemini wasn't designed to handle the thermal loads of constant sunlight for several days at a time. Granted, Apollo needed to do passive thermal control rolls, and Gemini could have done the same thing -- but these kinds of thermal effects hadn't been considered when Gemini was designed. This issue alone might have ended up killing the idea, had it gotten that far.
And remember, you'd have to dock with a much bigger propulsion module than a Centaur or a Titan transstage to do more than follow a figure-eight loop-around of the Moon with a Gemini. Yes, it would have been an historic moment, and the Russians fought hard (though ultimately unsuccessfully) to pull off this very type of mission. But compared to what Apollo was capable of, and *designed* to do, trying this stunt with a Gemini was simply an unjustifiable risk.
-the other Doug -- Senior Member
But Gemini showed a pretty large maturation curve during its manned flights. There were lessons learned during Mercury that took a while to incorporate into Gemini, not the least of which were manufacturing lessons. And if it seemed to take a while for McDonnell-Douglas to learn from its own mistakes, think of how much harder it was for North American Aviation to learn anything from Gemini as it designed and built Apollo.
However, there is an element of heightened danger in flying a Gemini spacecraft that far from home that I think most people underestimate. While Gemini was a much safer spacecraft to fly by the end of the program than it was at the beginning, it suffered from a far higher malfunction rate than the Apollo flights eventually logged.
For example, one reason NASA didn't attempt flights longer than three or four days after the Gemini V and Gemini VII marathons was that a majority of the attitude control system thrusters had failed by the time each of those long-duration flights concluded. On Gemini V, in fact, the thrusters were in such bad shape that the crew was told the activate the re-entry control system two orbits prior to retrofire, to ensure positive control when setting up retrofire attitude.
The Gemini fuel cell system was notoriously finnicky, and always seemed to totter on the brink of reliability without actually achieving it. They didn't produce potable water, either -- the water those cells produced was full of an organic sludge euphemistically called the "brown fuzzies" by the engineers. If the cells put out too much water (as happened on one flight), you had a serious problem, since the nasty fuel cell water was used to pressurize the potable water tank. On a lunar flyby, such a problem could lead to a waterlogged outbound crew and a really thirsty inbound crew... not to mention the need to perturb the outbound trajectory frequently with "Constellation Urion".
Finally, the Gemini wasn't designed to handle the thermal loads of constant sunlight for several days at a time. Granted, Apollo needed to do passive thermal control rolls, and Gemini could have done the same thing -- but these kinds of thermal effects hadn't been considered when Gemini was designed. This issue alone might have ended up killing the idea, had it gotten that far.
And remember, you'd have to dock with a much bigger propulsion module than a Centaur or a Titan transstage to do more than follow a figure-eight loop-around of the Moon with a Gemini. Yes, it would have been an historic moment, and the Russians fought hard (though ultimately unsuccessfully) to pull off this very type of mission. But compared to what Apollo was capable of, and *designed* to do, trying this stunt with a Gemini was simply an unjustifiable risk.
-the other Doug -- Senior Member
Mark Wade has added PDF files of many original documents on
space, including a bunch on the circumlunar Gemini flight plans:
http://www.astronautix.com/data/index.htm
space, including a bunch on the circumlunar Gemini flight plans:
http://www.astronautix.com/data/index.htm
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