A Dewar tank sits in a C-5M Super Galaxy that is being worked on at the isochronal maintenance dock March 26, 2013, on Dover Air Force Base, Del. Using Air Force Smart Operations of the 21st Century, Airmen from Dover AFB upgraded the tank to improve the reliability and life expectancy of the C-5M. The tank contains liquid nitrogen for when a fire is detected in an non-manned area of the aircraft, the valves open releasing the nitrogen to the area pushing the oxygen out allowing the nitrogen to put out the fire. (U.S. Air Force photo/Airman 1st Class Ashlin Federick)