Blue Gemini would consist of two National Aeronautics and Space Administration (NASA) missions which would include a USAF co-pilot and would accomplish NASA objectives. These would be followed by two more NASA missions that would have USAF crews. Those missions would be devoted to NASA goals, but would include USAF experiments if possible. The final phase of Blue Gemini would consist of three dedicated USAF missions. One of these would be an Agena Target Vehicle rendezvous mission and it was possible that some of these later missions would carry only a single crew member, the other seat being occupied by experimental equipment. Possible payloads included a Manned Maneuvering Unit that would allow an astronaut to maneuver around the spacecraft, an advanced navigation system, an erectable structure, and a large ground mapping radar. The plan was to end Blue Gemini missions approximately four months before the debut of the MODS space station.
In December 1963 McNamara likewise approved the development of a Manned Orbital Laboratory (MOL) which was essentially a revived MODS. Blue Gemini should not be confused with the Gemini B spacecraft that was developed for MOL. Gemini B included a tunnel through its heat shield to enable the astronauts to reach the MOL spacecraft.