Discovery's payload bay doors swing shut one at a time with the aid of strongbacks.

In Orbiter Processing Facility-1 at NASA's Kennedy Space Center in Florida, space shuttle Discovery’s payload bay doors swing shut one at a time with the aid of yellow-painted strongbacks, hardware used to support and operate the doors when the shuttle is not in space. Discovery's payload bay doors are being closed for the final time during Space Shuttle Program transition and retirement activities.

Following the door closure, the vehicle will be powered down for the last time. Discovery is being prepared for public display at the Smithsonian’s National Air and Space Museum Steven F. Udvar-Hazy Center in Chantilly, Va., in 2012. For more information, visit http://www.nasa.gov/shuttle. Photo credit: NASA/Kim Shiflett