Abstract
The multi-channel scanning imager is one of the main payloads of a Geostationary earth orbit satellite of China,
which observe multi spectrum from earth. Passive thermal control was applied to decrease temperature rise when solar
intrusion at midnight, and heat compensation was made to decrease thermal fluctuation in one orbit. Effort was focused
on the scanning mechanism for its relatively strict temperature gradient requirement. In order to validate thermal control
scheme, thermal balance experiment scheme was planned. Considering the complexity of solar heat flux into sunshade,
solar simulator was used to precisely simulate the heat flux variation. Limited to the dimension of vacuum chamber and
solar simulator lamp, only the flux into sunshade was simulated by solar simulator, and other parts was simulated by
electrical heaters. The solar illuminated region was analysed in order to keep the total heat flux correct. Detailed test
process was figured out to carry out two kinds of heat flux simulation. Date were acquired and compared to thermal
analysis. Based on experiment condition, thermal model was constructed and modified. From analysis of all the effecting
factors, it is find that thermal contact resistance between heatpipes and heat dissipating plate can largely effect the
temperature of scanning mechanism. Thermal model of scanning mechanism was detailly constructed including features
effecting heat flux absorption and temperature distribution. After modification, the prediction ability of thermal model
was enhanced. And optimization of thermal design was made to decrease temperature level and gradient of scanning
mechanism. Thermal analyse was done to estimate the optimization, and its effectiveness was validated.
