High performance on-orbit boundary simulation for large spacecraft microvibration environment test

Micro-vibration environment test is aimed at evaluating the weak mechanical signal that may remarkably affect the imaging quality of the astronomical telescope. Through the micro-vibration environment test, not only the vibration response can be obtained, but also the satellite modal as well as the load transfer path(LTP). They are useful references for improving the telescope's imaging quality. In order to achieve the on-orbit free boundary in the laboratory, it is necessary to develop large bearing test fixture with low rigidity. This paper provides a model describing the satellite-boundary binary structure in a concise manner: (1) give a completed design recipe for developing free boundary fixture, (2) introduce the large deformation modal analysis theory into the frequency characteristic analysis; (3) compare the indicators between typical fixture design with the practical test. Result shows that the current CAE method that used to design the micro-vibration test fixture is valid in satellite environmental engineering. The method suggested in this paper has been applied to verify several optical satellites in China, to help them guarantee the stability of optical axis with high resolution. Such large-bearing low-rigidity boundary design ideology can also be useful reference for other facilities in many fields, to help get them a much more precise simulation outcome.