Small Satellite LEO Maneuvers with Low-Power Electric Propulsion

Abstract

Chemical propulsion currently provides the means for near-Earth satellite orbit maneuvers. As electric propulsion (EP) devices become more accepted and flight qualified, EP may enable increases in satellite payload mass while decreasing satellite propellant mass. The Air Force Operationally-Responsive Space (ORS) program proposes the use of commercially available and readily configurable satellite buses with masses of approximately 500 kg for near-Earth missions. This paper discusses three orbital maneuvers considered important in the characterization of EP use for satellites in near-Earth orbits. The first maneuver changes an orbit from low-Earth orbit (LEO) at 800 km to mediumEarth orbit (MEO) at 20,000 km. The second maneuver changes the inclination of an orbit at LEO by 90°, while the third maneuver rephases a satellite in LEO orbit by 180°. Each maneuver considers thruster specific impulse, Isp, from 1,000 to 3,000 s and thruster power from 100 W to 1.5 kW for a 500 kg satellite to obtain propellant mass and transfer time. In general, as Isp increases the transfer time increases and the propellant mass decreases. These transfer times range from hours to years, but mission constraints will define appropriate levels of Isp and power. Analysis of these maneuvers finds that EP is beneficial to near-Earth satellites for altitude and phase changes. EP is not currently beneficial to missions requiring large inclination changes, but identifies a key interest in future low-power EP devices.