Tom Stafford - Space Rocket History Podcast

The Gemini Program was conceived after it became evident to NASA officials that an intermediate step was required between Project Mercury and the Apollo Program. The major objectives assigned to Gemini were:
1-To subject two men and supporting equipment to long duration flights — a requirement for projected later trips to the moon or deeper space.
2-To effect rendezvous and docking with other orbiting vehicles, and to maneuver the docked vehicles in space, using the propulsion system of the target vehicle for such maneuvers.
3-To perfect methods of reentry and landing the spacecraft at a pre-selected land-landing point.
4-To gain additional information concerning the effects of weightlessness on crew members and to record the physiological reactions of crew members during long duration flights.