11 November 1966, 20:46:33.419 UTC, T minus Zero

Gemini XII lifts off from LC-19 at 2:21:04 p.m., EST, 11 November 1966. (NASA)
Gemini XII lifts off from LC-19 at 3:46:33 p.m., EST, 11 November 1966. (NASA)

11 November 1966: Gemini 12 lifted off from Launch Complex 19 at the Cape Canaveral Air Force Station, Florida, at 3:36.33.419 p.m., Eastern Standard Time. NASA Astronauts James A Lovell, Jr., and Edwin E. (“Buzz”) Aldrin, Jr. were the crew. This was the second space flight for Lovell, who had previously flown on Gemini VII, and would later serve as Command Module Pilot on Apollo 8 and Mission Commander on Apollo 13. It was Aldrin’s first space flight. He would later be the Lunar Module Pilot of Apollo 11, and was the second human to set foot of the surface of the Moon.

The Gemini 12 mission was to rendezvous and docking with an Agena Target Vehicle, which had been launched from Launch Complex 14, 1 hour, 38 minutes, 34.731 seconds earlier by an Atlas Standard Launch Vehicle (SLV-3), and placed in a nearly circular orbit with a perigee of 163 nautical miles (187.6 statute miles/301.9 kilometers) and apogee of 156 nautical miles (179.5 statute miles/288.9 kilometers).

The two-man Gemini spacecraft was built by the McDonnell Aircraft Corporation of St. Louis, the same company that built the earlier Mercury space capsule. The spacecraft consisted of a reentry module and an adapter section. It had an overall length of 19 feet (5.791 meters) and a diameter of 10 feet (3.048 meters) at the base of the adapter section. The reentry module was 11 feet (3.353 meters) long with a diameter of 7.5 feet (2.347 meters). The weight of the Gemini varied from ship to ship, but Spacecraft 12 weighed 8,296.47 pounds (3,763.22 kilograms) at liftoff.

The Titan II GLV was a “man-rated” variant of the Martin SM-68B intercontinental ballistic missile. It was assembled at Martin’s Middle River, Maryland plant so as not to interfere with the production of the ICBM at Denver, Colorado. Twelve GLVs were ordered by the Air Force for the Gemini Program.

The Titan II GLV was a two-stage, liquid-fueled rocket. The first stage was 63 feet (19.202 meters) long with a diameter of 10 feet (3.048 meters). The second stage was 27 feet (8.230 meters) long, with the same diameter. The 1st stage was powered by an Aerojet Engineering Corporation LR-87-7 engine which combined two combustion chambers and exhaust nozzles with a single turbopump unit. The engine was fueled by a hypergolic combination of hydrazine and nitrogen tetroxide. Ignition occurred spontaneously as the two components were combined in the combustion chambers. The LR-87-7 produced 430,000 pounds of thrust (1,912.74 kilonewtons).¹ It was not throttled and could not be shut down and restarted. The 2nd stage used an Aerojet LR-91 engine which produced 100,000 pounds of thrust (444.82 kilonewtons).²

The Gemini/Titan II GLV combination had a total height of 109 feet (33.223 meters) and weighed approximately 340,000 pounds (154,220 kilograms) when fueled.³

Astronaut Buzz Aldrin standing in the open hatch of Gemini XII in Earth orbit. (NASA)

Gemini XII was the tenth and last flight of the Gemini program. The purpose of this mission was to test rendezvous and docking with an orbiting Agena Target Docking Vehicle and to test extravehicular activity (“EVA,” or “space walk”) procedures. Both of these were crucial parts of the upcoming Apollo program and previous problems would have to be resolved before the manned space flight projects could move to the next phase. Buzz Aldrin had made a special study of EVA factors, and his three “space walks,” totaling 5 hours, 30 minutes, were highly successful. The rendezvous and docking was flown manually because of a computer problem, but was successful. In addition to these primary objectives, a number of scientific experiments were performed by the two astronauts.

Gemini XII is tethered to the Agena TDV, in Earth orbit over the southwest United States and northern Mexico. (NASA)
Gemini XII is tethered to the Agena TDV, in Earth orbit over the southwest United States and northern Mexico. (NASA)

Gemini XII reentered Earth’s atmosphere and splashed down in the Atlantic Ocean, just 3.8 nautical miles ( statute miles/ kilometers) from the planned target point. Lovell and Aldrin were hoisted aboard a Sikorsky SH-3A helicopter and transported to the primary recovery ship, USS Wasp (CVS-18). Total duration of the flight was 3 days, 22 hours, 34 minutes, 31 seconds.

Gemini XII astronauts Major Edwin E. Aldrin, Jr., USAF, and Captain James A. Lovell, Jr., USN, arrive aboard USS Wasp (CVS-18), 15 November 1966. (Bettman/Corbis)
Gemini XII astronauts Major Edwin E. Aldrin, Jr., USAF, and Captain James A. Lovell, Jr., USN, arrive aboard USS Wasp (CVS-18), 15 November 1966. (Bettman/Corbis)

¹ Post-flight analysis gave the total average thrust of GLV-12’s first stage as 458,905 pounds of thrust (2,041.31 kilonewtons)

² Post-flight analysis gave the total average thrust of GLV-12’s second stage as 99,296 pounds of thrust (441.69 kilonewtons)

³ Gemini XII/Titan II GLV (GLV-12) weighed 345,710 pounds (156,811 kilograms) at Stage I ignition.

© 2017, Bryan R. Swopes

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Source: This Day in Aviation