Ultrasonic Evaluation of Bolted Connections in Satellites

Prolonged periods from conception to deployment of a satellite can undermine a time dependent mission. Currently, the timeline for a new satellite to reach deployment is on the order of years. The need for a more efficient process is evident and has lead to innovations at every aspect of satellite design and pre-launch testing. One such example is the development of panels and components that are prefabricated for space flight and capable of assembly in a variety of configurations. However, all final systems regardless of component qualification must be validated for space flight. Current qualification testing can take weeks to years. An ultrasonic technique based on the energy of a transmitted wave across the connection is intended either as an alternative to traditional vibration/qualification testing or as a precursor to in-situ monitoring of panel-to-panel connections. Transmitted elastic wave energy is used to assess the integrity of the connection in reference to an initially established baseline. An experiment was conducted on a functional satellite to test the feasibility of deploying this test method under realistic circumstances. A second experiment was conducted to test the repeatability of the test method and to find an appropriate range of test parameters.