Launch and Early Orbit phase
In spacecraft operations, the Launch and Early Orbit phase (LEOP) is one of the most critical phases of a mission. Spacecraft operations engineers take control of the satellite after it separates from the launch vehicle up to the time when the satellite is safely positioned in its final orbit.
During this period, operations staff works 24 hours a day to activate, monitor and control the various subsystems of the satellite, including the deployment of any satellite appendages (antennas, solar array, reflector, etc.), and undertake critical orbit and attitude control manoeuvres.
For geostationary satellites, the launch vehicle typically carries the spacecraft to Geostationary Transfer Orbit, or GTO. From this elliptical orbit, the LEOP generally includes a sequence of apogee engine firings to reach the circular geostationary orbit.