Gemini 12 was the tenth flight in the Gemini program. It was also the final flight in a program that bridged the Mercury and Apollo programs. It was also the 18th manned American flight and the 26th spaceflight of all time(acknowledging X-15 flights over 100 km). James Lovell was the Command Pilot, with Edwin “Buzz” Aldrin as Pilot. The mission was scheduled to rendezvous and dock with the Agena target vehicle, conduct three Extra Vehicular Activities (EVA), conduct a tethered station keeping exercise, perform docked maneuvers using the Agena propulsion system to change orbit, and demonstrate an automatic reentry. Additionally, there were fourteen scientific, medical, and technological experiments on board.
Gemini 12 was launched on November 11, 1966 and entered a 160.8 x 270.6 km Earth orbit. Later that same day, rendezvous with the Gemini Agena Target Vehicle (GATV) was achieved. The GATV had been launched an hour and a half before Gemini 12. It took 28 minutes after rendezvous to achieve docking. Docking took longer than expected because the astronauts had to rely on visual sighting due to problems with the onboard radar. During insertion of the GATV into orbit an anomaly was noted in the primary propulsion system, so the plan to use the GATV to lift the docked spacecraft into a higher orbit was abandoned. Instead, two phasing maneuvers using the GATV secondary propulsion system were conducted to allow the spacecraft to visualize with the November 12 total eclipse over South America.
The first EVA took place on November 12. Aldrin mounted a camera to the side of the spacecraft and collected a micrometeorite experiment. The next day, during the second EVA, Aldrin, attached to a 9 meter umbilical cord, worked in the hatch and nose area, and then moved to the adapter section where he worked in a panel mounted on the rear of the adapter. There he performed 17 manual tasks. He then moved to the target vehicle adapter area and carried out another series of tasks, including attaching a 30 meter tether to the Gemini adapter bar. After a rest period, Gemini 12 undocked from the GATV, moved to the end of the tether connecting the two vehicles, and began the tether experiment. The tether tended to remain slack, but the crew believed the two craft slowly attained gravity-gradient stabilization. The last EVA took place on November 14. Aldrin took photographs, conducted additional experiments, and jettisoned unused equipment.
The automatic reentry sequence began with retrofire on November 15, 1966. Splashdown occurred at 2:21:04 p.m. in the western Atlantic a mere 4.8 km from target. All primary mission goals were successfully accomplished except performance of maneuvers using the Agena propulsion system. The mission successfully completed several experiments including: frog egg growth under zero-g, synoptic terrain photography, synoptic weather photography, nuclear emulsions, airglow horizon photography, UV astronomical photography, and dim sky photography. Two micrometeorite collection experiments and three space phenomena photography experiments, were not fully completed.
The training and EVA conducted on Gemini 12 were designed to prepare astronauts and ground crew for future Apollo missions. In general the entire Gemini program was considered a success, leading to the future Apollo mission to the lunar surface.
We have written many articles about Gemini 12 for Universe Today.
Edwin Aldrin
Project Mercury and Project Gemini
If you’d like more info on Gemini 12, check out these articles:
Gemini 12 Spacecraft Details
Gemini 12 Project
We’ve also recorded an entire episode of Astronomy Cast all about Space Capsules. Listen here, Episode 124: Space Capsules, Part 1: Vostok, Mercury and Gemini.
Sources:
http://science.ksc.nasa.gov/history/gemini/gemini-xii/gemini-xii.html
http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1966-104A
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