Small GEO Satellite: Chemical ProPulsion Sub-System (CPPS) Thermal Design and Lessons Learned

Small-GEO is a general-purpose small geostationary satellite platform that is giving European industry the opportunity to play a significant role in the commercial telecom market. Small-GEO has been developed by an industrial team managed by OHB System SE. The Thermal Control System CDR close-out was successfully closed and the integration tasks have just been accomplished. The satellite is now on his way to TVAC test facility. Small-GEO foresees three different types of propulsion systems,namely chemical, electrical and cold gas. This paper describes the Satellite Platform Chemical Propulsion SubSystem (CPPS) TCS which uses mainly passive concepts complemented with heaters either thermostatically or software regulated. The sizing cases used to design and verify the thermal control system will be presented as well as the flight predictions both for transfer and geostationary phases. Since the CPPS is primarily involved in the manoeuvers at the very beginning of life of the spacecraft, the CPPS design is strictly connected to the LEOP (Launch Early Operational Phases), being the primary task to put the spacecraft itself in the correct final geostationary orbit. An overview of the early phases selected sizing sequence will be presented within the worst-case envelope scenarios; they involve not only the thrusters and LAE but the control units and the related piping. Then the relevant results will be shown and discussed.The last part of the paper deals with the problems encountered, the solutions adopted and the lessons learnt during the design and optimization steps.