In NASA Kennedy Space Center’s Orbiter Processing Facility Bay 3, workers inspect and measure thermal protection system gap fillers in Discovery’s forward and midbody areas. This work is being performed after two gap fillers were found protruding from the underside of Discovery on the July 26 Return to Flight mission, STS-114. New installation procedures are being developed to ensure the gap fillers stay in place and do not pose any hazard on re-entry to the atmosphere. The white strings stretching across the belly of the orbiter separate prioritized work zones. The work seen here is in zone 1.