Advanced Propulsion for Geostationary Orbit Insertion and North-South Station Keeping

Abstract

Solar electric propulsion technology is currently being used for geostationmT satellite station keeping. Analyses show tint electric propulsion technologies can be used to obtain additional increases in payload mass by using them to perform part of the orbit transfer. Three electric propulsion technologies are examined at two power levels for geostationary insertion of an Atlas HAS class spacecraft. The onboard chemical propulsion apogee engine fuel is reduced in this analysis to allow the use of electric propulsion. A numerical optimizer is used to determine the chemical burns that will minimize the electric propulsion transfer times. For a l&_-kg Atlas HAS class payload, increases in net mass (geostationary satellite mass less wet propulsion system mass) of 150--8N kg are enabled by using electric propulsion for station keeping, advanced chemical engines for part of the transfer, and electric propulsinn for the remainder of the transfer. Trip times are between one and four months.

Low-Thrust Control of a Lunar Mapping Orbit

“…While the terminal boundary conditions for Controller A are found by evaluating equation (13), the terminal boundary condition for Controller B corresponds to x(t f ) given, where x(t f ) corresponds to a polar, Sun-synchronous orbit. The additional requirement that the terminal state correspond to a polar orbit was included in order to ensure that the inclination is never allowed to stray very far from 90°.…”

“…Much recent work related to low-thrust stationkeeping [13][14][15] considers the stationkeeping of satellites in geostationary orbit about Earth. In each of these works, it is desired to stationkeep the orbit by minimizing the variations in latitude and longitude, therefore maintaining the satellite over a certain position on Earth.…”

“…The additional requirement that the terminal state correspond to a polar orbit was included in order to ensure that the inclination is never allowed to stray very far from 90°. Essentially, the six conditions given by equation (13) are traded with another set of conditions, x(t f ) given, so that the problem still has twelve boundary conditions [20].…”

Launch vehicle and power level impacts on electric GEO insertion

“…2,3,4,5,6,7 Hughes is offering the use of electric propulsion for part of the orbit insertion to increase their 702 spacecraft payload. 8…”

Autonomous Low-Earth-Orbit Station-Keeping with Electric Propulsion

“…While the use of such technology on commercial geostationary satellites and deep space missions are widely discussed in the literature (e.g. [1][2][3][4][5]), relatively few studies have been proposed for low Earth orbit (LEO) missions. Nevertheless, the EP capability of providing continuous thrust over several thousands of hours, together with the reduced propellant mass consumption, allows for accurate LEO station-keeping operations over sufficiently long duration missions.…”