Gemini B, OV4-3, & OV4-1R/T

Orbiting Vehicle or OV, originally designated SATAR, was a series of American satellites operated by the US Air Force.

The Gemini capsule was redesigned for Manned Orbiting Laboratory (MOL) and named Gemini B. Externally it was similar to Gemini, but featured a rear hatch for the crew to enter MOL and many specific systems.