Preventing Unwanted Vibrations in the Environmental Test of Random Vibrations of a Spacecraft by Power Spectrum Density Notching

The purpose of this study is to provide a method to prevent unwanted vibrations in environmental tests of random vibrations of spacecraft. Unwanted vibrations in many environmental random vibration tests will lead to the hidden fault (hiding failure) that would be happened in operational conditions in a space mission. Hence, in this research, first, a method called the power spectrum density notching method was presented to prevent unwanted vibrations, and then, by using the obtained analytical relationships, environmental random vibration tests of a sub-orbital spacecraft were performed. After the test, the recorded results by the fixture and payload's accelerometer sensors have been analyzed. In this analysis, the performance of the power spectrum density notching method was examined. The obtained results indicate, although the power spectrum density notching method is a simple, practical, and operational method but can be an efficient method to prevent unwanted vibrations to spacecraft and also prevent damage to spacecraft during testing.