United Space Alliance technician Larry Tanner punches three holes in the gap filler to be installed on Discovery.

United Space Alliance technician Larry Tanner punches three holes in the gap filler to be installed on Discovery. The holes are used for the string pull test done after installation to ensure the gap filler is bonded properly. Discovery is being processed in Orbiter Processing Facility Bay 3 at NASA’s Kennedy Space Center. This work is being performed due to two gap fillers that were protruding from the underside of Discovery on the first Return to Flight mission, STS-114. New installation procedures have been developed to ensure the gap fillers stay in place and do not pose any hazard during the shuttle's re-entry to the atmosphere. Discovery is the scheduled orbiter for the second space shuttle mission in the return-to-flight sequence.