Manned Orbiting Laboratory

The Manned Orbiting Laboratory (MOL), originally referred to as the Manned Orbital Laboratory, was a never-flown part of the United States Air Force’s human spaceflight program, a successor to the cancelled Boeing X-20 Dyna-Soar military reconnaissance space plane project. MOL evolved into a single-use laboratory, with which crews would be launched on 40-day missions and return to Earth using a Gemini B spacecraft, derived from NASA’s Project Gemini. The Gemini no.2 capsule used in the only flight of the MOL program is on display at the Air Force Space & Missile Museum at Cape Canaveral Air Force Station.

Source: en.wikipedia.org