Design of Mechanical and Thermal Intergrated Bracket for Star Sensor of High Orbit Satellite

Traditional light alloy metal material star sensor’s bracket have a thermal expansion coefficient of 10-5/℃, in a space thermal environment, pointing thermal deformation of star sensor mounting surface is relatively large, it can’t meet the requirement of a high precision satellite.The article gives a design method of a high rigidity and high precision micro deformation hot integrated bracket of star sensor, the test results show that the first order natural frequency of star sensor and bracket assembly is 178.4 Hz, has sufficient stiffness characteristics, the level of mechanical environment of the star senor mounting surface is much better than the allowable value, thus protects the star senor;and maximum thermal deformation of the star senor mounting surface is 6.41″, peak to peak value is 1.58″under extreme conditions, attitude determination accuracy of the satellite in orbit is better than 2.8″, the bracket meets requirements of high precision attitude determination and image navigation registration for a high orbit satellite.

This article focuses on the development requirements of a diagonal second level star sensor bracket for a high orbit satellite, and develops a high stiffness and high-precision micro deformation machine thermal integrated star sensor installation bracket. The bracket achieves heat dissipation of the star sensor through a heat pipe, and the heat pipe is connected to other structural components through a flexible device to achieve thermal deformation isolation; The heat collection plate in the bracket is made of a new type of aluminum based silicon carbide composite material, which not only improves heat transfer performance but also reduces the impact of thermal deformation on the surrounding structure; The main structure of the bracket is made of carbon fiber composite material, which ensures that the star sensor bracket has a high specific stiffness. The experiment shows that the first-order natural frequency of the star sensor bracket and the combination of star sensors is 178.4Hz, and the dynamic environment of the star sensor installation surface is good. At the same time, under extreme conditions of the spring equinox and summer solstice in orbit, the maximum change of the star sensor installation surface is 6.41 “, with a peak value of 1.58”, achieving an accuracy of satellite in orbit attitude determination better than 2.8 “, meeting the high-precision image positioning requirements of satellites.