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Author
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Topic: 'Gemini: Large Earth Orbit' (lunar Gemini)
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carmelo Member Posts: 1109 From: Messina, Sicilia, Italia Registered: Jun 2004
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posted 10-30-2005 10:07 AM
In June 1965 astronaut Pete Conrad conspired with the Martin and McDonnell corporations to advocate an early circumlunar flight using Gemini. Discretely called "Gemini - Large Earth Orbit," the plan would use a Titan 3C-launched Transtage to boost the Gemini to translunar speed. The flights themselves, assuming go-ahead was given in September 1965, would follow immediately after the last Gemini flight. In December 1966 a Titan 3C would drive a 2450 kg circumlunar Gemini capsule to 11 m/s re-entry velocity to verify the heat shield design. This would be followed by a February 1967 manned qualification flight in earth orbit. A manned Gemini would dock with a Double Transtage and be propelled into a high orbit and re-entry speed. In April the sequence would be repeated, this time the Gemini being sent by Transtage into a loop around the moon. The reaction of top NASA management was more categorical. Pete Conrad managed to stir Congressional interest, but NASA administrator James Webb informed them that any extra funds Congress cared to appropriate for such a project would be better spent accelerating the Apollo program. After further internal struggles, Conrad finally got NASA approval for the Agena on his Gemini 11 flight to boost him into a record 1,570 km orbit. This high flight was the only remnant of lunar Gemini. |
John Charles Member Posts: 342 From: Houston, Texas, USA Registered: Jun 2004
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posted 10-30-2005 11:37 AM
This is a very interesting story. I have heard this story before (but not with the dates), but it always seemed to be more of a legend than actual history. It prompts a few quetions - In June 1965, Cooper and Conrad were training for Gemini 5. Slayton said that he had to get the launch slipped a week or two to allow them to finish their training. How did Conrad have time to conspire with Martin and McDonnell if the crew was behind in their training? Or was it just Cooper that was behind?
- Being contractors, Martin and McDonnell generally did not do feasibility studies for free (or did they?), so how did Conrad have enough clout to get them funding (for somethin that HQ did not want, apparently) even before his first flight?
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robertsconley Member Posts: 61 From: Meadville, PA Registered: Jun 2005
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posted 10-30-2005 03:05 PM
He didn't. There was all kinds of contingency planning paid for by NASA, one of which was the use of Gemini to go to the moon. |
divemaster Member Posts: 1376 From: ridgefield, ct Registered: May 2002
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posted 10-30-2005 05:00 PM
Wally Schirra told me that there was no way that a Gemini heat sheild could withstand the reentry heat from a circumlunar flight. It was mere wishful thinking.
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carmelo Member Posts: 1109 From: Messina, Sicilia, Italia Registered: Jun 2004
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posted 10-30-2005 07:28 PM
It's right. The "lunar" Gemini spacecraft would have weighed 3,170 kg, an extra 270 kg over the basic rendezvous Gemini. The difference consisted of a backup inertial navigator and additional heat shielding for re-entry at 11 km/sec instead of 8 km/sec. A Titan 3C would drive a 2450 kg circumlunar Gemini capsule to 11 m/s re-entry velocity to verify the heat shield design. This would be followed by a manned qualification flight in Earth orbit. A manned Gemini would dock with a Double Transtage and be propelled into a high orbit and re-entry speed. After, the sequence would be repeated, this time the Gemini being sent by Transtage into a loop around the moon. Gemini Circumlunar Flyby Mission: - Titan III-C rocket liftoff: The 140.6-foot-tall rocket places a modified Titan III-C transtage into 100-mile-high LEO. Titan III-C consists of two strap-on solid rocket motors (Stage 0), a liquid-fueled core (Stage I), a liquid-fueled stage II, and a liquid-fueled standard transtage (transtage 1).
The modified transtage (transtage 2) reaches orbit riding on top of the standard transtage. Transtage 2 modifications include removal of systems to reduce weight and addition of a Gemini docking cone. - Gemini liftoff: The two-man Gemini, which consists of capsule, retro, and adapter sections, lifts off four minutes after the Titan III-C. A back-up Gemini launch opportunity occurs 90 minutes later when transtage 2 flies over Cape Canaveral at the end of its first orbit. The study notes that transtage 2 has a 7.5-hour usable lifetime in LEO, so the mission cannot occur if the second Gemini launch opportunity is missed.
The report states that Martin Marietta is examining transtage 2 modifications permitting a 30-day wait in LEO. - Gemini docks with transtage 2: Rendezvous occurs 90 minutes after Gemini launch, at the end of Gemini's first orbit, and docking occurs within three hours of Gemini launch. The astronauts insert their spacecraft's nose into transtage 2's docking cone.
According to the study, the "interface between the Gemini capsule and transtage 2 is designed for utmost simplicity." The standard Gemini docking umbilical and other spacecraft systems are only lightly modified for this mission; for example, rather than create a new transtage 2 status display panel in the Gemini cockpit, a panel which can be viewed through Gemini's twin windows is added to the transtage 2 docking cone. The Gemini/transtage 2 combination is 36 feet, 8 inches long. - Translunar injection (TLI) occurs about six hours after Gemini launch. The astronauts feel 0.6 Earth gravities of acceleration at transtage 2 ignition. They must be certain to secure their seat straps - because they face the front of transtage 2, acceleration pushes them out of their seats.
During acceleration they feel as though they are falling toward Gemini's nose. Transtage 2 burns for 6 minutes, 40 seconds. As transtage 2 depletes its propellants it becomes lighter. Acceleration thus increases, topping out at five times Earth's gravity at transtage 2 shutdown. - Gemini separation and circumlunar flight: The astronauts back away from transtage 2 and turn their spacecraft in the direction of flight. Midcourse corrections using the standard Gemini propulsion system occur between three and 10 hours after TLI and when circumlunar Gemini is 40,000 miles out from the moon. The Gemini spacecraft passes behind the moon 82 hours after TLI.
The mission is timed so the moon is in last-quarter phase as viewed from Earth - this means that half of the lunar far side is lit by the Sun, making it visible as the astronauts fly over. Additional midcourse maneuvers occur 40,000 miles after leaving the moon and between 5 and 10 hours before Earth atmosphere reentry. - Gemini reentry: The Gemini capsule casts off its adapter and retro sections, revealing a heatshield modified to withstand circumlunar speed (36,000 feet per second). The spacecraft passes through the atmosphere and splashes down in the Atlantic off Cape Canaveral. Total flight time is 143 hours.
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katabatic Member Posts: 72 From: Oak Hill, VA, USA Registered: Jun 2005
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posted 10-31-2005 07:41 AM
Five-G's eyeballs-out at shutdown? Wow.... |
Ted Peterson New Member Posts: 5 From: Registered: Jun 2024
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posted 08-30-2024 11:56 AM
Was there ever any serious consideration given to at least the practicality or possibility of a lunar flyby with Gemini? It would have been grueling I suppose, but Borman and Lovell were able to get a couple weeks out without strangling each other, so it might have been possible? I know they had similar work into a Gemini style service module. Editor's note: Threads merged. |
Headshot Member Posts: 1334 From: Vancouver, WA, USA Registered: Feb 2012
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posted 08-30-2024 01:43 PM
The possibility was explored to the point where necessary equipment was identified and basic trajectory analyses were made. NASA, however wanted to put Gemini behind them and no funds were ever allotted.An excellent 40+ page study of this "lost mission" was published in the Apogee book dealing with Gemini 12. |
davidcwagner Member Posts: 1053 From: Albuquerque, New Mexico Registered: Jan 2003
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posted 08-30-2024 07:33 PM
Did the Russians consider similar moon flight with rockets smaller than the gigantic N-1? No landing. |
Robert Pearlman Editor Posts: 53011 From: Houston, TX Registered: Nov 1999
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posted 08-30-2024 07:36 PM
Yes, the Zond program: The missions Zond 4 through Zond 8 were test flights for the Soviet Moonshot during the Moon race. The Soyuz 7K-L1 (also mentioned just as L1) spacecraft was used for the Moon-aimed missions, stripped down to make it possible to launch around the Moon from the Earth. They were launched on the Proton rocket which was just powerful enough to send the Zond on a free return trajectory around the Moon without going into lunar orbit (the same kind of path flown by Apollo 13 in its emergency abort). With minor modification, Zond was capable of carrying two cosmonauts.In the beginning, there were serious reliability problems with both the new Proton rocket and the similarly new Soyuz spacecraft, but the test flights pressed ahead with some glitches. The majority of test flights from 1967 to 1970 (Zond 4 to Zond 8) showed problems during re-entry. The Zond spacecraft made only uncrewed automatic flights. Four of these suffered malfunctions that would have injured or killed any crew. | |
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