Patent ID: 7113851

Claim:
A system for raising a spacecraft launched into a transfer orbit about the Earth from the transfer orbit to a geosynchronous orbit, comprising: a spacecraft comprising chemical and electric propulsion thrusters and a solar array; a processor onboard the spacecraft for: firing the chemical propulsion thrusters at apogees of intermediate orbits, starting from the transfer orbit initiated by the launch vehicle, to successively raise perigees of the orbit until the spacecraft perigee substantially clears the Van Allen radiation belts, and where the semi-major axis of the intermediate orbits is substantially less than the semi-major axis of a final orbit, and where the inclination of the intermediate orbits is substantially greater than the inclination of the final orbit; firing the electric propulsion thrusters to raise the orbit of the spacecraft from the orbit achieved by the chemical propulsion thrusters firing step to near geosynchronous orbit by steering the thrust vector both in-plane and out-of-plane while rotating the spacecraft body and steering the solar array to maintain the sun's illumination on the solar array, further comprising ground apparatus including a processor that determines a thruster firing profile for firing the thrusters and generates thruster firing commands that implement the thruster firing profile, and communication apparatus that uplinks commands to the spacecraft.