Impedance-based health monitoring of space shuttle ground structures

Abstract

Many of the structures responsible for the launch, ground turnaround and support operations of the space shuttle are still being used well past their design life. This has led to an increased interest in monitoring these structures in order to decrease the risk of breakdowns or structural failure. One monitoring method which has shown promising results for such applications is the impedance-based structural health monitoring technique. This paper presents results from proof-of-concept tests on the launch pad's orbiter access arm bolted connection, solid rocket booster support post, mobile launch platform heat shield and crawler transporter bearing. These tests showed that the impedance method can provide a permanent structural health monitoring solution to NASA's ground structures. In addition several positive and negative aspects of the impedance method were discovered or highlighted. Modifications for future tests are suggested.