U.S. Air Force Senior Airman Matthew Dillard, 100th Logistics Readiness Squadron cryogenic specialist from Las Vegas, drains pressure from a liquid oxygen storage tank Feb. 11, 2015, on RAF Mildenhall, England. It’s vital that the pressure is drained as the temperature in the tank reaches -297 degrees Fahrenheit because too much pressure could result in safety concerns. (U.S. Air Force photo by Gina Randall/Released)