PRELIMINARY DESIGN FOR SATELLITE THERMAL CONTROL SYSTEM

The purpose of this research is to determine the temperatures distribution of the satellite subsystems such as: MBEI, MIREI, GPS, Mt, MM, RW, SS, PCDHS, SF, SPU, Tel, and IB in order to determine the worst-case hot temperature (WCH) & worst-case cold temperature (WCC) expressions of the satellite and to study the continuously variable environmental and operating parameters of the LEO satellite to develop a preliminary design for a satellite thermal control subsystem. Also, the temperature of the PVC and external satellite surface are determined. This purpose will lead to maintain and continuously safely operate for all elements of the satellite subsystems within the allowed temperature limits, for all mission phases over the mission lifetime, subject to given ranges of environmental conditions and operating modes.
In this paper, the heat transfer models using finite difference codes for the base plate, basis plate, mounting plate, the external body surface, and the photovoltaic cell surface for the satellite are developed. An analytical thermal model is constructed. The heat sources and sinks, both external and internal, such as electronics packages, heaters, cooling devices, and radiators, node/network and thermal resistances between each pair of nodes are identified. The initial conditions and boundary conditions for start-up one orbital revolution, and after 6-revolution are selected. The thermal analysis for each satellite's component on the: base plate, basis plate, mounting plate, the satellite external body surface, and the photovoltaic surfaces are presented to determine the temperature distribution for steady state and transient conditions at various ranges of initial temperatures and boundary temperatures conditions.