after success of the Mercury spacecraft launch, NASA contracted
McDonnell to design a larger two-man Mercury mark II for longer periods
in orbit. This bigger spacecraft which soon renamed Gemini that require
a larger launch vehicle, a Titan II missile. The Titan II was Air Force
missile and naturally required close coordination with the Air Force.
The Air Force was interested in the Gemini program because it would be
ready much earlier than the Dyna-Soar spaceplane while Russians already
had men in orbit possibly carrying nuclear bombs. In 1962, the Air Force
had designated the spacecraft as Blue Gemini. It would essentially be an
off-the-shelf NASA Gemini vehicle.
In January 1963, Air Force and NASA officials went to Pentagon to
propose DoD participation in Blue Gemini, but was rejected and cancelled
by Secretary of Defense. Air Force had soon proposed other manned flight
program, the Manned Orbital Laboratory (MOL). It included Gemini B
spacecraft which modified from the Blue Gemini with
a tunnel through its heat shield to enable
the astronauts to reach the MOL spacecraft.
There was only one test flight of the Gemini B / MOL mockup in 1966.