An analysis of spacecraft dynamic testing at the vehicle level

Abstract

The US space industry has accumulated a vast amount of expertise in the testing of spacecraft to ensure these vehicles can endure the harsh environments associated with launch and on-orbit operations. Even with this corporate experience, there remains a wide variation in the techniques utilized to test spacecraft during the development and manufacturing process, particularly with regard to spacecraft level dynamics testing. This study investigates the effectiveness of sinusoidal vibration, random vibration, acoustic noise and transient methods of spacecraft dynamic testing. An analysis of test failure and on-orbit performance data for acceptance testing indicates that the acoustic test is the most perceptive workmanship screen at the vehicle level and that additional dynamics tests do not result in an increase in acceptance test effectiveness. For spacecraft qualification, acoustic testing is almost universally employed for qualification in the high frequency environment. For the low frequency environment, data collected from a variety of spacecraft test programs employing sinusoidal sweep, random vibration and transient testing methods shows that a transient base excitation provides the most accurate simulation for the purpose of design verification. Furthermore, data shows that sinusoidal vibration testing provides an unrealistic simulation of the flight environment and results in an increased potential for overtesting.