Europa Clipper Solar Array Mass Simulator (SAMS) Development for Spacecraft Dynamics Testing

The Europa Clipper Spacecraft has two large solar arrays that will not be integrated with the Spacecraft until after all environmental testing is complete and the Spacecraft has shipped to the launch site. This deviation in flight test configuration was driven by the development timeframe of the solar arrays as well as the Europa Clipper ATLO schedule, but posed many challenges to the mechanical team responsible for the modal, vibration, acoustics, and separation system testing of the Spacecraft. To accommodate the late delivery of the flight solar arrays, Solar Array Mass Simulators (SAMS) were developed to be used during the Spacecraft dynamic test campaigns. The SAMS are single panel aluminum honeycomb structures with aluminum face sheets that are mounted to the flight solar array struts. The SAMS were designed to have a first bending mode that matches the flight solar arrays and have an equivalent mass. The SAMS were a necessary component for the system modal and dynamics tests as the solar arrays represent significant mass and stiffness of the Spacecraft and are major contributors to primary modes of the system. The SAMS underwent their own dynamics qualification tests in which a major failure occurred during a sine test, resulting in a rework of both panels. Testing was successful following the rework of the panel and the SAMS were delivered to JPL for Spacecraft testing. The inclusion of SAMS instead of the flight solar arrays posed several challenges to the Spacecraft test as SAMS has significantly different modal content besides the first bending mode, and much less damping than the flight solar arrays. These differences required JPL to implement analysis and test strategies to ensure Spacecraft dynamics test objectives were met while considering the safety of hardware and personnel. The overall approach have been documented and accounted for in the test plans and limiting strategies for the system test, performed in November 2023.