Agena target vehicle

The Agena target vehicle (ATV) was a spacecraft used by NASA to develop and practice orbital space rendezvous and docking techniques in preparation for the Apollo program lunar missions.

Each ATV consisted of an Agena spacecraft built by Lockheed and a docking adapter built by McDonnell. The Agena was launched from Cape Canaveral Air Force Station Launch Complex 14 on top of an Atlas booster built by the Convair division of General Dynamics. The Agena first burn would occur shortly after shroud jettison and separation from the Atlas over the Atlantic Ocean. Over Ascension Island, a second burn would boost the Agena into a low circular orbit.

The McDonnell Gemini spacecraft would then launch (as close as 90 minutes) from Launch Complex 19 (both countdowns would proceed in parallel and required close synchronization) and, toward the end of the program, would dock with the Agena within the first orbit after launch.

The Gemini astronauts would then fly in a stabilized mode and perform a number of experiments:
*letting the Agena stabilize the formation to save the capsule's propellants (on the first docking, during the Gemini 8 mission, a stuck nozzle on the capsule resulted in an emergency undock and the mission termination)
*EVA and work on a tool panel (this required installing handrails on the next flight after one astronaut's heart rate exceeded safe limits due to the effort expended just holding on)
*lighting the Agena engine and reaching a record orbital apogee of 738 miles.
*undocking, unreeling a 50 foot (15.24 meter) nylon strap between the capsule and the Agena and flying in a "dumbbell" configuration with the Agena below the astronauts (to check the gravitational effect on the formation stability in uncontrolled mode. This is now known as Gravity-gradient stabilization.)
*using a similar tether and a few thruster bursts to rotate the two craft around each other as an early test of artificial gravity.

After the Gemini capsule separated for the last time, the Agena remained in orbit for a short time and was used to verify the command system.

Agena target vehicle flight statistics

External links

* [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19750069069_1975069069.pdf Gemini 6/Agena target vehicle 5002 systems test evaluation (PDF) December 1965]
* [http://www.maniacworld.com/Gemini-VIII-Docks.htm Gemini 8 Docks with Agena] Video