Thermal Control Technique Of Carbon Satellite Payload

Since industrial revolution, extensive deforestation and combustion of a large number of fossil raw materials have become serious. The content of carbon dioxide in the air is increased rapidly. So the greenhouse effect becomes more and more grievous. Previously, the monitoring of carbon dioxide is limited to the ground.Because of the limitation, the carbon dioxide global evolution are poorly understood,the space monitoring for carbon dioxide is paid attention all over the world. It is carried out with space optical instrument. The temperature of the instruments is directly related to its imaging quality. Thus, it is necessary to study the design of the detector’s thermal control system. Carbon satellite payload is first Chinese greenhouse gas detector. Its pose is complex and internal heat loads are pretty much and its working time is long.All of the factors put forward new challenges to the thermal design. The observed pattern of the detector is multiple and the change of monorail attitude is complicated, so it is difficult to determine the thermal design conditions. There are refrigerating machines for the infrared detector and its radiating is difficult because of the limited surface. The entire work of the detector will be affected if the thermal design is improper. The content of the thesis is how to use sophisticated thermal design technology to solve thermal design problems of the greenhouse gas detector in order to satisfy its working thermal control requirement.The present research status of optical remote sensor to detect greenhouse gasis summarized.The working characteristics and thermal design features of the greenhouse gas optical remote sensor are summarized. Besides, the thermal design scheme of foreign greenhouse gas optical remote sensor was introduced.The structure and working modes of China’s greenhouse gas optical remote sensor were analyzed. The difficulties and keys of the thermal control system are also stated.The thermal design targets for the Carbon Dioxide Detection Instrument(CDDI)and the Cloud And Aerosol Polarization Imager(CAPI) were studied with their thermal-optical analysis. The targets were decomposed to the parts of the sensors according to the structure.A concrete thermal design for the installed surface, main body, light entering,optical elements, detectors and electric cabinet of the carbon dioxide detection instrument was carried on in the thermal design part. Another thermal design for the main frame, lens components, baffles’ components, circuit boards components and focal planes components of the CAPI is also carried on. The hot case and cold case conditions are defined according to the instrument’s attitude and working modes. In order to define the radiating area and heating power, the work conditions were analyzed and calculated. The thermal analysis results indicated that in the cold case the temperature of the optical elements on the CDDI is 18.4 ℃ ~21.8 ℃ and the temperature of detector components is 18.5 ℃ ~25.5 ℃ and in the hot case the temperature of the optical elements on the CDDI is 18.6 ℃ ~22.0 ℃ and the temperature of detector’s components is 20.6 ℃ ~25.7 ℃.It meets the target. The results also indicated that in the cold case the temperature of CAPI’s objective lens assembly is 19℃~23℃ and in the hot case its temperature is 19℃~23℃. That also meets the target. In addition, the baffle structure scheme of the CAPI is optimized.According to the research on a certain baffle, it is concluded that the length of the baffle is best at 1.7 times of its equivalent diameter. Then the experiment of the CAPI’s baffle is carried out and its optimization result is acquired.Finally, the thermal test for the carbon satellite payloads is discussed. The results of the thermal balance test indicate that the temperature of the main body inthe CDDI in the cold case is 16.4℃~19.6℃ and its detector’s temperature is 15.1℃~16.4℃ and the temperature of the main body in the CDDI in the hot case is 17.8℃~19.6℃ and the detector’s temperature is 18.5℃~23.3℃. Meanwhile, in the cold case the temperature of the CAPI’s objective lens assembly is 16.4℃~18.9℃ and in the hot case its temperature is 18.9℃~19.9℃. So the thermal design targets are met.A conclusion could be forward that thermal analysis data is effective and reliable and the thermal design is reasonable and feasible.