scope:

Abstract:

After Galileo completed its second Earth flyby, communication signal levels received on Earth decreased and fluctuated unexpectedly. The cause was determined to be interference that was not detected during test because the test article was not consistent with the orbiter telecommunications functional requirements document.

Recommendations involved use of concurrent engineering, verification of requirements compliance, updating of requirements documents based on hardware ECR's, post test evaluation of non-flight like characteristics, and assuring that hardware used for functional testing properly simulates the characteristics of the flight hardware.