After the launch and commissioning of the first Turkish remote sensing satellite BILSAT-1, TUBITAK BILTEN has initiated the RASAT microsatellite project. RASAT will be a remote sensing microsatellite at low Earth orbit (LEO), with a mass of around 100 kg and an orbital average power of 38W. RASAT is planned to be launched in 2007 and will be the first satellite to be designed and manufactured entirely in Turkey. The main objective of RASAT is to perform Earth-observation using a 5- to 8-meter-resolution imager. In addition to its imaging capability, RASAT will be a platform to demonstrate current technologies using experimental payloads. Small satellites used for Earth-observation require high data transfer rates and one of the experimental payloads in RASAT is an X-Band communication subsystem intended to meet this requirement for future projects. X-band subsystem power amplifier has the overall efficiency of about 26%. Therefore, it will dissipate about 20W during data transfer and thermal issues will become important both at system and at subsystem level. As the mission analyses of RASAT have not yet been concluded, in this paper, the thermal environment and survivability of the X-Band subsystem in orbit is investigated under many uncertainties: the minimum and maximum temperatures for RASAT have been defined for LEO, the X-Band subsystem is assumed to be placed in three nano-trays and for critical nano-trays a robust thermal-mathematical model has been created for hot-case analyses. Transient and steady state temperatures of the critical components have been calculated, and the steady state temperature distribution of the PCB has been estimated. Calculations have Indicated that the components on X-Band modules do not exceed upper temperature limits in RASAT and a passive thermal control method is still feasible for a system dissipating such high power.
Feasibility study on thermal survivability of X-band subsystem on RASAT microsatellite
2005-01-01
856337 byte
Conference paper
Electronic Resource
English
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