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Gemini Lunar Lander
Part of Gemini

Lunar Gemini

Lunar Gemini

American manned lunar lander. Study 1961. A direct lunar lander design of 1961, capable of being launched to the moon in a single Saturn V launch through use of a 2-man Gemini re-entry vehicle instead of the 3-man Apollo capsule.

Status: Study 1961. Gross mass: 18,500 kg (40,700 lb). Height: 12.47 m (40.91 ft). Span: 6.61 m (21.68 ft).

Following the preliminary decision to proceed with the lunar orbit rendezvous technique for the Apollo lunar landing mission, there was one final effort to return to the simpler direct landing approach. Lunar orbit rendezvous would require a three-man Apollo capsule, in order for a crew of two to reach the lunar surface while the third crewmember tended the waiting Apollo in lunar orbit. But if the objective was to land two men on the moon, why use the three-man Apollo capsule? Why not use either the two-man Gemini capsule, or a reduced size two-man Apollo-shaped capsule to land directly on the moon? Such a spacecraft could be propelled toward the moon on a single launch of the Saturn C-5 rocket, just like the LOR version.

McDonnell, builders of the Mercury and Gemini spacecraft, were given the contract to make a study of the alternate approach. The result showed it was indeed feasible, at less cost, risk, complexity, and time, then the LOR 3-man Apollo. The only problem was that the existing work done on the North American three-crew Apollo would have to be scrapped, and either a modified Gemini or a new two-crew Apollo developed in its place. Wiesner, Kennedy's science adviser, was an enthusiastic about the approach. NASA, North American, and the competitors for the lunar module contract were distinctly less interested. Webb, the NASA Administrator, finally got the idea spiked once and for all. Although Gemini lunar landers would be advocated again, as rescue vehicles, or whenever Apollo ran into development trouble, they would never get past the very preliminary paper stage.

Major ground rules for the study were:

Three modifications of the Gemini design were considered for the direct lunar landing:

Weight summary was as follows:

The major Gemini Guidance and Navigation components utilized were the inertial system and computer. Additions for Lunar Gemini I included an auto sextant and the Apollo tracking and landing radars (total system weight - 155 kg). Additions for Lunar Gemini II and III included the Apollo sextant/telescope, the Apollo tracking and landing radars, and a roll momentum wheel for use during manual navigation (total system weight - 166 kg).

The power system provided was essentially the same as that used in the 14-day Gemini with some off-loading of fuel cell reactants and the addition of increased sequential control provisions. A detailed electrical load analysis indicated that the mission requirements were 660 watts average for Gemini I and 880 watts average for Lunar Gemini II and III. Sufficient fuel was provided for the full 8 day mission, two days of which were contingency.

Conventional spacecraft structures were employed in all modules, following the proven materials and concepts demonstrated in the Mercury and Gemini designs. Primary structure of each module consisted of a semimonocoque shell with reinforcements around cut-outs and fittings to distribute localized loads. Titanium was used as the basic shell material in all modules except the service module where beryllium sheet was used for the structural radiator shell.

Re-entry heat protection was conservatively designed for a shallow long range re-entry or a 20 g structural limit re-entry, whichever resulted in the greater protection requirements. The ablative material was MAC Thermorad Shield S-3 elastomeric composite. Nominal thermophysical properties were used in the calculations and a 1.15 factor was applied to predicted heating rates. The total ablative material design weight was 232 kg for Lunar Gemini I and II, and 221 kg for Lunar Gemini III.

Crew Size: 2. Habitable Volume: 2.55 m3.

Family: Lunar Landers, Moon. People: McDonnell. Country: USA. Spacecraft: Apollo Direct RM, Apollo Direct SM, Apollo Direct TLM, Gemini Lunar RM. Launch Vehicles: Saturn V. Agency: NASA. Bibliography: 2180.

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