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Gemini 12 Target



The Gemini 12 Agena Target Vehicle (GATV 5001) was launched from Cape Canaveral at 2:07:58 p.m. EST (19:07:58.688 UT) on 11 November 1966 into a near-circular 300 km orbit using an Atlas-Agena D rocket. During the target vehicle ascent manuever, 140 seconds after primary propulsion system initiation, a 30-psi drop occuerred in thrust chamber pressure for 1 second, then returned to normal for the remaining 42 seconds of firing. The anomaly did not affect the GATV orbit insertion, but uncertainties about the significance of the pressure drop caused cancellation of the plan to use the primary propulsion system to lift the spacecraft into higher orbit after docking with Gemini 12. The Gemini 12 spacecraft, launched an hour and 40 minutes later, rendezvoused and docked with GATV at 8:00 p.m. Two phasing maneuvers using the GATV secondary propulsion system were accomplished to allow the spacecraft to rendezvous with the November 12 total eclipse over South America at about 9:20 a.m. EST. On 13 November Buzz Aldrin began a two-hour EVA at 10:34 a.m. After performing tasks on the Gemini 12 spacecraft, he moved to the target vehicle adapter area and carried out a series of tasks, including use of a torque wrench while tethered. He attached a 30 meter long tether stowed in the GATV adapter to the Gemini adapter bar. At 3:09 p.m. Gemini 12 undocked from the GATV, moved to the end of the tether connecting the two vehicles, and began the tether experiment by moving in a circular orbit about the GATV. The tether tended to remain slack, but the crew believed the two craft slowly attained gravity-gradient stabilization. The tether was released at 7:37 p.m., the GATV was left in a 260 x 295 km orbit.

Gemini Agena Target Vehicle

The Gemini Agena Target Vehicle was designed to be launched into Earth orbit prior to a Gemini mission and used for rendezvous and docking practice. The GATV had a docking cone at the forward end into which the nose of the Gemini spacecraft could be inserted and held with docking latches. The GATV was a 7.93 meter long cylinder with a diameter of 1.52 meters, a dry mass of 1830 kg, and a fueled mass at orbital injection of 3228 kg. The forward section of the Agena airframe held the guidance, flight control electronics, telemetry, command, tracking, electrical power, and propellant pressurization equipment. The primary and secondary propulsion systems were at the aft end of the target vehicle with the attitude control gas tanks, and the main propellant (fuel and oxidizer) tanks were located in the mid-section. Propulsion was via a bi-propellant system, using unsymmetrical dimethylhydrazine (UDMH) and inhibited red fuming nitric acid (IRFNA). The Agena propulsion systems could be run while the Gemini was docked, allowing the GATV to be used to change the orbit of the docked pair. A minimum of five engine starts was possible. The docking cone was connected to the front end by shock absorbing dampers. Acquisition running lights and target vehicle status display indicators were situated on the front end. A 2.1 meter long retractable L-band boom antenna extended from the side of the cylinder near the front. Tracking and command of the GATV were also aided by a rendezvous beacon, two spiral L-band antennas, two tracking antennas (C-band and S-band), two VHF telemetry antennas, and a UHF command antenna. Micrometeoroid packages and other experiments could also be mounted on the GATV.

Gemini Program

The Gemini program was designed as a bridge between the Mercury and Apollo programs, primarily to test equipment and mission procedures in Earth orbit and to train astronauts and ground crews for future Apollo missions. The general objectives of the program included: long duration flights in excess of of the requirements of a lunar landing mission; rendezvous and docking of two vehicles in Earth orbit; the development of operational proficiency of both flight and ground crews; the conduct of experiments in space; extravehicular operations; active control of reentry flight path to achieve a precise landing point; and onboard orbital navigation. Each Gemini mission carried two astronauts into Earth orbit for periods ranging from 5 hours to 14 days. The program consisted of 10 crewed launches, 2 uncrewed launches, and 7 target vehicles, at a total cost of approximately 1,280 million dollars.

Alternate Names

  • 02565
  • Agena Target Vehicle 12
  • GATV-5001
  • Gemini12Target

Facts in Brief

Launch Date: 1966-11-11
Launch Vehicle: Atlas-Agena D
Launch Site: Cape Canaveral, United States
Mass: 1830 kg

Funding Agency

  • NASA-Office of Manned Space Flight (United States)


  • Engineering

Additional Information

Questions and comments about this spacecraft can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Dr. Charles W. MathewsProject ManagerNASA Headquarters
Dr. William C. SchneiderProject ManagerNASA Headquarters
Dr. George E. MuellerProgram ManagerNASA

Selected References

  • Gemini summary conference, NASA, SP-138, Wash, DC, Feb. 1967.
  • Grimwood, J. M., et al., Project Gemini technology and operations - A chronology, NASA, NASA SP-4002, Wash., DC, 1969.
Drawing of Gemini and the Gemini Agena Target Vehicle

Gemini and Gemini Agena Target Vehicle.

Gemini 12

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