First Orbital Maneuver By Manned Spacecraft
On March 23, 1965 at 15:57:00 UTC, at the end of the first orbit, over Corpus Christi, Texas, a 1 minute 14 second burn of the orbit attitude and maneuvering system (OAMS) engines gave a delta-V of 15.5 meters per second; which was the first orbital maneuver by any manned spacecraft. The orbit was changed from 161.2 kilometres (100.2 mi) x 224.2 kilometres (139.3 mi), period 88.3 minutes to an orbit of 158 kilometres (98 mi) x 169 kilometres (105 mi), period 87.8 minutes.
Read more about this topic: Gemini 3