Ground Guided CX-OLEV Rendez-vous with Uncooperative Geostationary Satellite
- Paper number
IAC-06-C1.6.01
- Author
Mr. Lorenzo Tarabini, GMV S.A., Spain
- Coauthor
Mr. Jesus Gil-Fernandez, GMV S.A., Spain
- Coauthor
Mr. Fernando Gandia, GMV S.A., Spain
- Coauthor
Mr. Miguel Angelo Molina, GMV S.A., Spain
- Coauthor
Mr. Juan Manuel del Cura, SENER Ingeneria y Sistemas, S.A., Spain
- Coauthor
Dr. Guillermo Ortega, European Space Agency (ESA)/ESTEC, The Netherlands
- Year
2006
- Abstract
Orbital Servicing Limited’s CX-OLEV (ConeXpress-Orbital Life Extension Vehicle) is a "tugboat" aimed to extend the operational life of geostationary (GEO) telecommunications satellites. CX-OLEV is designed to rendez-vous and mate with GEO satellites to supply them propulsion, navigation and guidance services. Under SENER’s contract and ESA’s supervision, GMV designed the CX-OLEV ground guided rendez-vous (RV) approach that will be described in details in the paper. The aiming point of the CX-OLEV transfer phase is approximately at GEO’s altitude and at a relative distance between ConeXpress and the client spacecraft in the order of one km. The uncertainty of the ground-based CX-OLEV-client radar relative navigation is in the order of 250 m (3σ). This scenario is the starting point of the rendez-vous phase between ConeXpress and the client. Due to the stringent mass, volume and computational power constraints two redundant optical cameras are selected as rendez-vous sensors. The CX-OLEV cameras images are sent to ground and processed to determine the relative position of the spacecraft and to calculate, validate and transmit in near real time the rendez-vous manoeuvres commands. Space-ground-space delay in the order of 5 to 10 seconds is considered in the spacecraft control loop. The objective of the designed CX-OLEV rendezvous strategy is to safely approach the client satellite along the client’s zenith direction up to a relative distance of 5 meters. The approach allows the client satellite to keep its operational attitude and to broadcast during the CX-OLEV rendez-vous operations.
The RV is performed keeping the RV cameras pointed towards the client. The relative spiral motion of CX-OLEV around the telecommunication satellite is synchronized with the Sun-GEO-CXOLEV angle to guarantee a good illumination of the client minimizing the shadow on the client satellite solar panels that could damage them.
The rendez-vous phase is composed of three modes: a Camera Acquisition mode commanded to acquire the GEO within the camera’s field of view, an Orbit Manoeuvre mode to apply the manoeuvre calculated on ground and an Hold Point manoeuvre to correct deviations and wait for authorization from ground to continue the RV. The RV is also supported by a set of contingency plans in case of violation of the approach corridors to maximize the client’s safety. Once reached the final RV position at 5 m from the client, CX-OLEV stabilizes its position and attitude to start the docking procedure. The complete RV is simulated in a dedicated environment. The simulations demonstrate the concept feasibility and assess the robustness and the safety of the designed CX-OLEV rendez-vous operations.
- Abstract document
- Manuscript document
IAC-06-C1.6.01.pdf (🔒 authorized access only).
To get the manuscript, please contact IAF Secretariat.