The analysis of affections to the cold space calibration source of ChangE-1 payload Microwave Detector

ChangE-1 (CE-1) will be the first satellite of China in lunar orbit. Its Microwave Detector makes real-time and periodical calibration at high and low temperature points. The low brightness temperature calibration source will be provided by calibration antenna which is pointing towards the cold space.This paper focuses on analyzing solar radiation affections to the cold space calibration source while the satellite is in lunar orbit. We get the following results:1.Solar radiation affections are maximal when the satellite is right facing the sun and the maximal brightness temperatures which close to the original antenna temperature T are 86.3200, 85.6700, 31.0020, 29.8905 K, respectively.2.The incidence of solar radiation affections in forward-flight is smaller than in sideward-flight, and the affections fluctuate rapidly in forward-flight when reaching to and leaving from the peak value. But when in sideward-flight, they are smoothly descending all the time.3.The solar radiation affections to channel 1 (3 GHz) and channel 2 (7.8 GHz) are almost as three times high as to the other two channels.4.The affections to E plane, H plane and 45° plane of the same channel are quite similar.These results not only provide important theoretical reference to Microwave Detector’s calibration, but also would be useful when observing the earth in future.