Gemini-Agena
Target Vehicle
The Agena's engine firing on the Gemini X mission. (NASA)
Project Gemini needed an
adequate vehicle for the later missions to use as a target for
rendezvous and docking. Responding to this
need,
McDonnell Douglas modified its pre-existing Agena upper rocket stage to
become
the Gemini-Agena Target Vehicle. This modified spacecraft
now had a docking collar, a radar beacon, and a restartable rocket
engine.
The Agena was launched on an Atlas rocket. Of six launches,
two were destroyed before they reached orbit. The first successful
docking with an Agena came on the Gemini VIII mission, with other
dockings occuring on the Gemini X, XI, and XII missions. The experienced gained from
using the Agena Target Vehicle in practicing docking with the Gemini spacecraft was indispensable in
sending men to the
moon.