KSC-05pd-1587

KENNEDY SPACE CENTER, FLA. - Patricia Slinger (left), a test engineer, and Monica Hagley, an avionics test engineer, look at a replacement orbiter point sensor chassis. Components are being tested to determine why one of the four liquid hydrogen tank low-level fuel cut-off sensors failed in a routine prelaunch check during the launch countdown July 13. The failure caused mission managers to scrub Discovery's first launch attempt. The sensor protects the Shuttle's main engines by triggering their shutdown in the event fuel runs unexpectedly low. The sensor is one of four inside the liquid hydrogen section of the External Tank (ET).