Geosynchronous-Earth-Orbit Communication Satellite Deliveries with Integrated Electric Propulsion

The use of electric propulsion was evaluated for transfer of communication satellites from geosynchronous transfer orbits to geosynchronous earth orbits. Recent communication satellite designs, normal launch vehicle delivery orbits, and integrated electric propulsion subsystems (with input powers less than nominal satellite power levels) were assumed to minimize required changes to present and near-term launchers and spacecraft. The capture fraction of recent communication satellites that could have been delivered was evaluated versus launcher delivery capability, launch site, and in-space propulsion characteristics. Electric propulsion significantly increases the capture fraction of launchers with geosynchronous transfer mass delivery capabilities less than (dependent on launch site) about 4500 to 5500 kg. Insertion times at given launch sites were found to be accurately specified by the satellite power-to-mass ratios and the assumed electric propulsion specific-impulse/efficiency characteristics. Insertion times less than 100 days were found for satellites with high power-to-mass ratios that used high thrust-to-power electric propulsion options. The influence of power for electric propulsion beyond that used for satellite payloads and housekeeping was also assessed, and insertion times less than a month will require powers significantly higher than presently installed.