Gemini 12 (officially Gemini XII) was a 1966 crewed spaceflight in NASA's Project Gemini. It was the 10th and final crewed Gemini flight (Gemini 1 and Gemini 2 were uncrewed missions), the 18th crewed American spaceflight, and the 26th spaceflight of all time, including X-15 flights over . Commanded by Gemini VII veteran James A. Lovell, the flight featured three periods of extravehicular activity (EVA) by rookie Edwin "Buzz" Aldrin, lasting a total of 5 hours and 30 minutes. It also achieved the fifth rendezvous and fourth docking with an Agena target vehicle.

Gemini XII marked a successful conclusion of the Gemini program, achieving the last of its goals by successfully demonstrating that astronauts can effectively work outside of spacecraft. This was instrumental in paving the way for the Apollo program to achieve its goal of landing a man on the Moon by the end of the 1960s.

Crew

Backup crew

Support crew

  • Stuart A. Roosa (Cape CAPCOM)
  • Charles "Pete" Conrad Jr. (Houston CAPCOM)
  • William A. Anders (Houston CAPCOM)

Mission parameters

  • Mass:
  • Perigee:
  • Apogee:
  • Inclination: 28.87°
  • Period: 88.87 min (1 hour, 28 minutes)

Docking

  • Docked: November 12, 1966 – 01:06:00 UTC
  • Undocked: November 13, 1966 – 20:18:00 UTC

Space walk

  • Aldrin – EVA 1 – (stand up)
  • Start: November 12, 1966, 16:15:00 UTC
  • End: November 12, 1966, 18:44:00 UTC
  • Duration: 2 hours, 29 minutes
  • Aldrin – EVA 2
  • Start: November 13, 1966, 15:34:00 UTC
  • End: November 13, 1966, 17:40:00 UTC
  • Duration: 2 hours, 06 minutes
  • Aldrin – EVA 3 (stand up)
  • Start: November 14, 1966, 14:52:00 UTC
  • End: November 14, 1966, 15:47:00 UTC
  • Duration: 0 hours, 55 minutes

Launch

Liftoff of the Atlas/Agena Target Vehicle occurred at 2:07:59 p.m. EST, and of the Gemini/Titan spacecraft at 3:46:33 p.m. EST, on November 11. In preparation for Gemini XII new, improved restraints were added to the outside of the capsule, and a new technique—underwater training—was introduced, which would become a staple of future space-walk simulation. The main purpose of the Gemini XII mission was to find and test new ways to work outside of a spacecraft safely and effectively. Ground controllers decided not to risk the planned orbital boost maneuver since the exact reason for the pump slowdown was unclear. Following Gemini 12's reentry and during the GATV's 63rd orbit, they attempted to fire the propulsion system, but a stuck fuel valve prevented engine start from occurring.

It was suspected that a turbopump bearing failure caused the anomalous conditions during orbital injection, followed by heating and melting of pump components. The inability of ground controllers to start the engine during the 63rd orbit was possibly due to melted or loose debris blocking the fuel valve and preventing its operation. The telemetry data falsely reporting erratic pump speed was concluded to be debris being knocked around and affecting the data probes.

right|thumb|Gemini 12 tethered stationkeeping

The 1994 book and documentary Moon Shot, as well as the 2008 documentary When We Left Earth: The NASA Missions, credits the spacewalk innovations, including the underwater training, to Aldrin himself. However, the 2016 article "Inventing Underwater Training for Walking in Space," by Michael Neufeld, reveals that neutral buoyancy experimentation began at aerospace companies and at NASA Langley Research Center in Hampton, Virginia a few years before the first Gemini mission had even flown.

Gemini 12 was designed to perform rendezvous and docking with the Agena target vehicle, to conduct three extravehicular activity operations, to conduct a tethered stationkeeping exercise, to perform docked maneuvers using the Agena propulsion system to change orbit, and demonstrate an automatic reentry.

{| class="wikitable plainrowheaders"

|-

! scope="col" | Gemini 12

! scope="col" | Agena info

|-

! scope="row" | Agena

| GATV-5001A

|-

! scope="row" | NSSDC ID:

| 1966-103A

|-

! scope="row" | Mass

|

|-

! scope="row" | Launch site

| LC-14

|-

! scope="row" | Launch date

| November 11, 1966

|-

! scope="row" | Launch time

| 19:07:59 UTC

|-

! scope="row" | 1st perigee

|

|-

! scope="row" | 1st apogee

|

|-

! scope="row" | Period

| 90.56 m

|-

! scope="row" | Inclination

| 28.86

|-

! scope="row" | Reentered

| November 15, 1966

|}

thumb|175px|Aldrin during an EVA

When Gemini 12 was being planned, one of the possibilities raised was the potential for the flight to be run in conjunction with the first Apollo mission, which had been tentatively scheduled for the last quarter of 1966. By May 1966, delays in making Apollo ready for flight just by itself, and the extra time needed to incorporate compatibility with the Gemini, made that impractical. This became moot when slippage in readiness of the Apollo spacecraft caused the last-quarter 1966 target date to be missed, and the Apollo mission was rescheduled for February 21, 1967.

Experiments

thumb|Gemini 12 crew after splashdown

The 14 scientific experiments were (1) frog egg growth under zero-g, (2) synoptic terrain photography, (3) synoptic weather photography, (4) nuclear emulsions, (5) airglow horizon photography, (6) UV astronomical photography, and (7) dim sky photography. Two micrometeorite collection experiments, as well as three space phenomena photography experiments, were not fully completed.

Reentry

The capsule was controlled on reentry by computer and splashed down 4.8 kilometers from its target. The crew were taken aboard the aircraft carrier .

The Gemini 12 mission was supported by the following U.S. Department of Defense resources; 9,775 personnel, 65 aircraft and 12 ships.

Postflight medical examination disclosed no unusual conditions in either astronaut. Both were slightly exhausted and dehydrated due to problems with the spacecraft's water supply system forcing them to reduce their fluid intake on the last day of the mission and Lovell had a mild case of pinkeye.

Insignia

thumb|left|Gemini 12 space-flown [[NASA space-flown Robbins medallions of the Apollo missions#Gemini mission space-flown Fliteline medallions|Fliteline Medallion]]

The patch's unique orange and black colors are a link to the flight's original scheduled date close to Halloween. The Roman numeral XII is located at the 12 o'clock position on the face of a clock, with the Gemini spacecraft pointing to it like the hour hand of a clock. This represents the position of Gemini 12 as the last flight of the Gemini program. With the Apollo project following this last flight of the Gemini program, the ultimate objective—the Moon—is symbolized by the crescent on the left.

<gallery mode="packed" heights="145">

File:S66-63387 PR.jpg|The Gemini 12 spacecraft and the Agena, photographed at apart during docking.

File:Gemini 12 prime crew (Aldrin and Lovell).jpg|Gemini 12 prime crew: Astronauts James A. Lovell Jr. (right), command pilot, and Edwin E. Aldrin Jr., pilot.

File:Gemini 12 Splashdown - GPN-2000-000994.jpg|Parachuted descend of Gemini 12.

File:Gemini and Agena D.jpg|Agena Vehicle as seen from Gemini 12 during docking mission.

File:Gemini XII Mission Image - Solar Eclipse.jpg|Solar eclipse photograph taken by the Gemini 12 crew (November 12).

</gallery>

Spacecraft location

thumb|The Gemini 12 space capsule at Chicago's [[Adler Planetarium]]

After several years at the Museum of Transport and Technology, in Auckland, New Zealand, the spacecraft was returned to the United States. It is now on display at the Adler Planetarium, Chicago, Illinois. Lovell and Aldrin were reunited with the spacecraft on November 9, 2006 during the opening for Adler's "Shoot for the Moon" exhibit, almost 40 years after the mission launched.

See also

  • Agena target vehicle
  • Extravehicular activity
  • Lists of spacewalks and moonwalks
  • Splashdown
  • Solar eclipse of November 12, 1966
  • Space suit

References

  • NASA Gemini 12 press kit – November 3, 1966
  • Gemini 12 Mission Report (PDF) January 1967
  • NASA Space Science Data Coordinated Archive
  • U.S. Space Objects Registry