Station keeping strategy for geo satellites with low thrust electrical propulsion and limitations in the thrust direction. application to the conexpress project.
- Paper number
IAC-06-C1.5.04
- Author
Mr. Alberto Sebastian, SENER Ingeneria y Sistemas, S.A., Spain
- Coauthor
Mr. Juan Manuel del Cura, SENER Ingeneria y Sistemas, S.A., Spain
- Coauthor
Mrs. Laura Torres, SENER Ingeneria y Sistemas, S.A., Spain
- Year
2006
- Abstract
ConeXpress is a future S/C based on the use of an Ariane 5 cone adaptor that can be adapted to several payloads and missions. The ConeXpress Orbital Life Extension Vehicle mission is intended to service GEO telecommunication satellites that are almost finishing their mission lifetime while the payload is still in a good shape. CX-OLEV, once docked to the Client S/C, will extend its lifetime for some years performing all the actions related to the AOCS. One of the most critical tasks to be done, while servicing a GEO satellite, is the Station Keeping process in order to maintain the S/C inside the specified limits in both, longitude and inclination, counteracting the main disturbances acting in GEO. Most of the potential clients for ConeXpress are based in typical platforms with high thrust chemical propulsion, performing Station Keeping manoeuvres based in two impulses to correct, both, longitude drift and eccentricity and more frequent manoeuvres to perform inclination correction. ConeXpress will have to perform this task by mean of EP thrusters mounting on moving arms with high limitations in terms of orientation. The use of this configuration presents the following drawbacks: - Low thrust capability (a typical Delta V strategy is not feasible). - Limitations in thrust direction: location of the thrusters is such that thrust vector has always three components (Nadir, East/West and North/South), making impossible to obtain pure E/W thrust. The purpose of this paper is to describe the way that Station Keeping manoeuvres are to be performed when the previous constraints have to be considered. The combination of the components of the thrust vector allows to combine N/S STK with eccentricity control on a daily basis scheme and with E/W STK in a less frequent operation. Optimization of the E/W thrust required to take advantage of the natural drift is also presented.
- Abstract document