Gemini 12 (officially Gemini XII)[3] 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 100 kilometers (54 nmi). 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.
![]() Buzz Aldrin performs an EVA during the Gemini XII mission, with the Agena Target Vehicle visible in the background | |
Mission type |
|
---|---|
Operator | NASA |
COSPAR ID | 1966-104A ![]() |
SATCAT no. | 2566 |
Mission duration | 3 days, 22 hours, 34 minutes, 31 seconds |
Orbits completed | 59 |
Spacecraft properties | |
Spacecraft | Gemini SC12 |
Manufacturer | McDonnell |
Launch mass | 3,762 kilograms (8,294 lb) |
Landing mass | 1,947 kilograms (4,293 lb) |
Crew | |
Crew size | 2 |
Members | |
EVAs | 3 |
EVA duration | 5 hours, 30 minutes |
Start of mission | |
Launch date | November 11, 1966, 20:46:33 (1966-11-11UTC20:46:33Z) UTC[1] |
Rocket | Titan II GLV |
Launch site | Cape Kennedy LC-19 |
End of mission | |
Recovered by | USS Wasp |
Landing date | November 15, 1966, 19:21:04 (1966-11-15UTC19:21:05Z) UTC |
Landing site | 24°35′N 69°57′W[1] |
Orbital parameters | |
Reference system | Geocentric |
Regime | Low Earth orbit |
Perigee altitude | 251 kilometers (136 nmi) |
Apogee altitude | 289 kilometers (156 nmi) |
Inclination | 28.8 degrees |
Period | 89.94 minutes |
Epoch | November 14, 1966[2] |
Docking with GATV-5001A | |
Docking date | November 12, 1966, 01:06:00 UTC |
Undocking date | November 13, 1966, 20:18:00 UTC |
Time docked | 1 day, 19 hours, 12 minutes |
![]() ![]() (L-R) Aldrin, Lovell Project Gemini |
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.
Position | Astronaut | |
---|---|---|
Command Pilot | James A. Lovell Jr Second spaceflight | |
Pilot | Edwin E. "Buzz" Aldrin Jr First spaceflight |
Position | Astronaut | |
---|---|---|
Command Pilot | L. Gordon Cooper Jr. | |
Pilot | Eugene A. Cernan |
Liftoff of the Atlas/Agena Target Vehicle occurred at 2:07:59 PM EST, and of the Gemini/Titan spacecraft at 3:46:33 PM EST, on November 11.[1] All launch vehicle systems performed nominally during powered flight, but at staging there was a recurrence of the first stage oxidizer tank rupture first seen on Gemini 10's launch. On Gemini 12, the fuel tank appeared to have also ruptured as a white cloud was seen emitting from the spent stage along with the orange nitrogen tetroxide. Another episode of "Green Man" also occurred at SECO, referring to pitch gyrations caused by pressure buildup in the second stage protective skirt.
At the completion of the previous Gemini flight, the program still had not demonstrated that an astronaut could work easily and efficiently outside the spacecraft. Prior to the Gemini XII mission, other astronauts from previous missions of the Gemini Program had attempted EVAs. However, their successes were limited due to a lack of proper restraints and insufficient techniques.[4] 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.[4] Aldrin's two-hour, 20-minute tethered space-walk, during which he photographed star fields, retrieved a micrometeorite collector and did other chores, at last demonstrated the feasibility of extravehicular activity. Two more stand-up EVAs also went smoothly, as did the by-now routine rendezvous and docking with an Agena which was done "manually" using the onboard computer and charts when a rendezvous radar failed. The climb to a higher orbit, however, was canceled because of a problem with the Agena booster.
During orbital injection, the GATV engine experienced a drop in turbopump speed lasting about 2.5 seconds. After this, pump performance returned to normal. Telemetry data indicated erratic pump speeds, but engine performance did not reflect this. The anomaly was later found as a brief 30 psi drop in the thrust chamber of the rocket. The mission had planned for an orbital maneuver into a higher orbit but the drop in pressure raised some concerns.[5] 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.
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.[6]
Gemini 12 was designed to perform rendezvous and docking with the Agena target vehicle, to conduct three extra-vehicular activity (EVA) operations, to conduct a tethered stationkeeping exercise, to perform docked maneuvers using the Agena propulsion system to change orbit, and demonstrate an automatic reentry.
Gemini 12 | Agena info |
---|---|
Agena | GATV-5001A |
NSSDC ID: | 1966-103A |
Mass | 3,175 kilograms (7,000 lb) |
Launch site | LC-14 |
Launch date | November 11, 1966 |
Launch time | 19:07:59 UTC |
1st perigee | 294.7 kilometres (183.1 mi) |
1st apogee | 303.2 kilometres (188.4 mi) |
Period | 90.56 m |
Inclination | 28.86 |
Reentered | November 15, 1966 |
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.[7] 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.[8]
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.
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 USS Wasp.
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.
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.
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 November 9, 2006 during the opening for Adler's "Shoot for the Moon" exhibit, almost 40 years after the mission launched.[9]
This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.
Project Gemini | ||||||
---|---|---|---|---|---|---|
Missions |
| ![]() | ||||
Astronauts |
| |||||
Components |
| |||||
Launch sites |
| |||||
Developments |
| |||||
Related |
|
NASA | |||||||
---|---|---|---|---|---|---|---|
Policy and history |
| ||||||
Human spaceflight programs |
| ||||||
Robotic programs |
| ||||||
Individual featured missions (human and robotic) |
| ||||||
Communications and navigation |
| ||||||
NASA lists |
| ||||||
NASA images and artwork |
| ||||||
Related |
| ||||||
|
← 1965 · Orbital launches in 1966 · 1967 → | |
---|---|
Kosmos 104 | OPS 2394 | OPS 7253 · OPS 3179 | Kosmos 105 | Kosmos 106 | OPS 1593 | Luna 9 | OPS 7291 | ESSA-1 | OPS 1439 | Kosmos 107 | Kosmos 108 | OPS 1184 · OPS 3011 · OPS 3031 | Dipason | Kosmos 109 | DS-K-40 No.2 | Kosmos 110 | ESSA-2 | Kosmos 111 | OPS 3488 | GATV-5003 | Gemini VIII | Kosmos 112 | OPS 0879 · OPS 0974 | Kosmos 113 | N-4 No.3 | OPS 1117 | Molniya-1 No.5 | OV1-4 · OV1-5 | OPS 0340 | Luna 10 | Kosmos 114 | OPS 1612 | Surveyor SD-3 | OAO-1 | OPS 0910 | Kosmos 115 | OV3-1 | Molniya 1-03 | Kosmos 116 | OPS 1508 | Kosmos 117 | Kosmos 118 | OPS 1950 · OPS 6785 | Nimbus 2 | Zenit-4 | GATV-5004 | OPS 0082 | OPS 1788 | Kosmos 119 | Explorer 32 | Surveyor 1 | ATDA | Gemini IX-A | OPS 1577 · OPS 1856 | OGO-3 | Kosmos 120 | OV3-4 | FTV-1351 · Secor 6 · ERS-16 | OPS 9311 · OPS 9312 · OPS 9313 · OPS 9314 · OPS 9315 · OPS 9316 · OPS 9317 · GGTS | Kosmos 121 | OPS 1599 | PAGEOS | Kosmos 122 | Explorer 33 | AS-203 | Proton 3 | Kosmos 123 | OPS 1850 | OV1-7 · OV1-8 | Kosmos 124 | GATV-5005 | Gemini X | Kosmos 125 | Kosmos 126 | OPS 3014 | OV3-3 | Kosmos 127 | OPS 1545 | Lunar Orbiter 1 | OPS 1832 · OPS 6810 | Pioneer 7 | OPS 2366 | FTV-1352 · Secor 7 · ERS-15 | Luna 11 | IDSCP 1 · IDSCP 2 · IDSCP 3 · IDSCP 4 · IDSCP 5 · IDSCP 6 · IDSCP 7 · GGTS | Kosmos 128 | GATV-5006 | Gemini XI | OPS 6026 | OPS 1686 · OPS 6874 | Zenit-2 No.40 | OPS 6026 | OPS 1686 · OPS 6874 | OGCh No.05L | Surveyor 2 | OPS 1703 | Ōsumi 1 | OPS 4096 | ESSA-3 | FTV-1583 · Secor 8 | OPS 2055 · OPS 5345 | Kosmos 129 | Molniya 1-04 | Kosmos 130 | Luna 12 | Surveyor SM-3 | Intelsat II F-1 | OV3-2 | OGCh No.06L | OPS 2070 · OPS 5424 | OPS 0855 · OV4-1R · OV4-1T · OV1-6 | Lunar Orbiter 2 | OPS 1866 | GATV-5001A | Gemini XII | Kosmos 131 | Strela-2 No.1 | Kosmos 132 | Kosmos 133 | Kosmos 134 | OPS 1890 | ATS-1 | OV1-9 · OV1-10 | Kosmos 135 | Soyuz 7K-OK No.1 | OPS 8968 | Biosatellite 1 | Kosmos 136 | Ōsumi 2 | Kosmos 137 | Luna 13 | OPS 1584 | |
Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in underline. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in brackets. |