Shock Testing Failure Investigation of the Europa Clipper Magboom

Recent shock qualification testing of the Europa Clipper Spacecraft’s Magboom showed significant hardware response amplification at 120Hz, 360Hz, and 1500Hz in the shock response spectrum, resulting in hardware failure. To investigate the behavior of these excited modes, acceleration data was bandpass filtered around each of the modal frequencies, which showed significant load levels of 150-200g at 120 and 360Hz and 1000g at 1500Hz. Sustained excitation of all three modes with increasing number of cycles at higher frequencies suggest that the excitation of the primary structural mode at 120Hz is contributing to secondary excitation of the higher frequency modes. Peak relative velocity of over 400 inches per second was calculated at 120 Hz, further indicating significant hardware stress that likely led to higher frequency excitation by introducing impact-type loading, which may have contributed to the hardware failure. The amplification observed during the shock test was unexpected due the interfaces between the shock source and failure location, which according to NASA standards, should have resulted in significant reduction in shock energy. The unexpected hardware responses highlight the potential deficiencies of using knockdown standards for shock level derivation, necessitating development of robust analysis tools to predict shock environments at critical flight hardware interfaces.