NASA Logo, National Aeronautics and Space Administration
NASA Space Science Data Coordinated Archive Header

Gemini 9 Target A



The Gemini 9 Agena Target Vehicle (vehicle GATV 5004) was intended as a docking target for the Gemini 9 mission, scheduled to launch 99 minutes after the GATV. Launch of the GATV took place at 10:12 a.m. EST (15:12 UT) on 17 May 1966. At 120.6 seconds after liftoff, the Atlas no. 2 booster engine swiveled to an extreme hardover position about 10 seconds before booster engine cutoff. The other booster and sustainer engine, under autopilot, worked to counter the asymmetrical thrust, but the vehicle pitched downward and after booster separation the vehicle continued flying under sustained thrust, having pitched down 216 degrees from the 67 degree nominal position, so it was flying north back toward Cape Kennedy at a climbing angle of 13 degrees above horizontal. It had also rolled to a position where ground guidance could not lock on. The vernier engines cut off at 300 seconds. The Agena separated on schedule and both vehicles plunged into the sea about 172 km northeast of the launch site, 145 km off the coast of Florida seven and a half minutes after launch. Radar data from the Grand Bahama Island station at 436 seconds after launch placed the vehicle about 191.6 km from the launch site at 29,500 meters altitude, headed north and descending. The exact reason for the loss of engine pitch control was unknown, data indicated that a short-to-ground occurred in the circuit for the servoamplifier output command signal. The short may have been caused by cryogenic leakage in the thrust section. Scheduled launch of the Gemini 9 spacecraft was cancelled.

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 and a dry mass of 1820 kg. At launch it carried 6360 kg of fuel and gas, and had an orbital injection mass of roughly 3252 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

  • GATV-5004
  • Gemini9TargetA

Facts in Brief

Launch Date: 1966-05-17
Launch Vehicle: Atlas-Agena D
Launch Site: Cape Canaveral, United States
Mass: 1820 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.

Gemini 9

Gemini Home Page

[] NASA Logo -