High Quality Content by WIKIPEDIA articles! Advanced Gemini is a collective name given to a number of proposals which would have extended the Gemini program by the addition of various missions, including manned low Earth orbit, circumlunar and lunar landing missions. Gemini was the second manned spaceflight program operated by NASA, and consisted of a two-seat spacecraft capable of maneuvering in orbit, docking with unmanned spacecraft such as Agena Target Vehicles, and allowing the crew to perform tethered extra-vehicular activities.