Mechanical Analysis and Optimization of A Star Tracker Baffle

The baffle is an important part of the star sensors to resist stray light, which is generally a lightweight thin-walled structure. In addition to ensuring the realization of optical indicators, it also needs to pay attention to its mechanical properties. The baffle shell of a star sensor was fractured during the qualification level random vibration test. The problem was analyzed and investigated. Through finite element simulation analysis, the maximum stress of the baffle exceeds the allowable stress of the material under the excitation of the test load, and the position is consistent with the actual fracture position. The problem phenomenon can be repeated by retesting, which fully explains that the insufficient safety margin of design is the direct cause of the problem. On this basis, the safety margin is effectively improved by optimizing and simulating the structure, and finally passes the vibration test.

An investigation was conducted on the shell fracture phenomenon of a certain star sensor’s light shield during the random vibration test at the identification level. After finite element simulation analysis, the maximum stress position located was consistent with the fracture position, exceeding the allowable stress of the material, indicating that the original design safety margin was insufficient. After comparing the stress changes in the weak positions under four optimization schemes, the final choice was to optimize the structural form of the hood shell, change the right angle transition to an oblique angle transition, and increase the wall thickness. Without changing the envelope size and installation interface, the stress level was effectively reduced, and the safety margin of the hood was improved. Finally, it passed the experimental assessment.