Workers in bay 3 of the Orbiter Processing Facility check the progress of the orbiter boom sensor system as it is lowered into place in Discovery's payload bay. It was removed last week in order to inspect the power system, which is routine after every flight. Discovery returned from mission STS-121 in late July, and is now being processed for mission STS-116, scheduled to launch in mid-December. Photo credit: NASA/Jim Grossmann