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| A GT-12 launch cover from "Orbit Covers" postmarked at Cape Canaveral on November 11, 1966, signed by Edwin "Buzz" Aldrin and James A. Lovell. |
Gemini 12 (GT-12), launched on November 11, 1966, marked the last manned mission of Project Gemini. The crew consisted of James A. Lovell and Edwin E. Aldrin. This mission aimed to perform rendezvous and docking with the Agena target vehicle, conduct three Extravehicular Activity (EVA) operations, execute a tethered stationkeeping exercise, carry out docked maneuvers using the Agena's propulsion system for orbital changes, and demonstrate automatic reentry capabilities.
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| Photo: Buzz Aldrin and James Lovell get ready to begin a practice run in the spacecraft simulator. |
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| Photo: James Lovell is learning how to operate a movie camera, getting ready for the significant task of capturing footage during the Gemini 12 flight. |
At the end of the previous Gemini flight, the program had yet to demonstrate that an astronaut could work effectively outside the spacecraft. Although astronauts from earlier Gemini missions had attempted EVAs, their achievements were hindered by inadequate restraints and techniques. To prepare for Gemini 12, enhanced restraints were added to the exterior of the capsule, and a new technique—underwater training—was introduced, which would become a fundamental method for simulating spacewalks in the future.
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| Photo: James Lovell and Buzz Aldrin reviewing their Gemini 12 flight plans for their upcoming spaceflight, which has faced another delay, marking the second consecutive postponement. |
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| A GT-12 launch cover featuring a Kennedy Space Center NASA official cachet designed specifically for the mission, postmarked with a Kennedy Space Center machine cancel on November 11, 1966, signed by James A. Lovell and Buzz Aldrin. |
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| A GT-12 launch cover featuring a Kennedy Space Center NASA official cachet, postmarked with a Kennedy Space Center hand cancel on November 11, 1966. |
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| A GT-12 launch cover from "Centennial" postmarked at Cape Canaveral on November 15, 1966, signed by James Lovell and Buzz Aldrin. |
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| Photo: The launch of Gemini 12 on November 11, 1966. |

The primary objective of the Gemini 12 mission was to discover and test new methods for safely and effectively working outside a spacecraft. Aldrin's two-hour, 20-minute tethered spacewalk, during which he photographed star fields, retrieved a micrometeorite collector, and completed other tasks, successfully demonstrated the feasibility of EVA operations. Additionally, two more stand-up EVAs went smoothly, as did the routine rendezvous and docking with an Agena, which was accomplished manually using onboard computer systems and charts after the rendezvous radar failed. However, the planned ascent to a higher orbit was canceled due to a problem with the Agena booster. Gemini 12 marked a successful conclusion to the Gemini program, achieving its final goals by demonstrating that astronauts could effectively work outside spacecraft. This success was crucial in paving the way for the Apollo program to achieve its objective of landing a man on the Moon by the end of the 1960s.
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| Photo: the Agena target vehicle glided through space at the end of a 100 foot tether attached to the Gemini 12 capsule during the four day orbital journey. |
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| Photo: Buzz Aldrin conducting stand-up Extravehicular Activity (EVA) operations. |
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| A cover with a cachet depicting Buzz Aldrin with a micrometeorite collector during an extravehicular activity (EVA) postmarked at Houston, Texas, on November 15, 1966. |
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| Photo: The Gemini 12 capsule splashed down in the Atlantic Ocean, landing just four miles from the aircraft carrier Wasp. Nearly immediately after the capsule hit the water, navy frogmen from the recovery team jumped from a helicopter to attach flotation gear to the spacecraft and assist the astronauts. |
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| A GT-12 Captain's Cover featuring a hand cancel from the USS Wasp dated November 15, 1966. |
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| A GT-12 Crew Cover (Type 2) on ship's stationery from the USS Wasp, featuring a black “Morris Beck” rubber-stamped cachet, mailed from the ship on November 15, 1966. The cover includes a letter written by John Cashman. |
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| A GT-12 recovery cover from the USS Wasp, featuring a black “Morris Beck” rubber-stamped cachet and and a machine cancel dated November 15, 1966. It is signed by James Lovell, Buzz Aldrin, Rear Admiral P.W. Jackson, Captain Melvin R. Etheridge, helicopter pilot LCdr. Sam Aydelotte. |
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| Two GT-12 recovery covers featuring a printed “Morris Beck” cachet. The upper cover, designated B706, bears a USS Wasp hand cancel, which is less common than the machine cancellations typically seen on similar covers. The lower cover, designated B711, is the correct cover for the USS Wasp. |
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| A GT-11 recovery cover from the USS Wasp, featuring a printed “Morris Beck” cachet and a machine cancel dated November 15, 1966. |
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| A GT-11 recovery cover from the USS Wasp, featuring a magenta “Morris Beck” rubber-stamped cachet and a hand cancellation dated November 15, 1966. |
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| Photo: The Gemini 12 crew during a news conference on November 23, 1966. |
(Reference from
Gemini 12)