U.S. Air Force Senior Airman Ryan Kane, 552nd Aircraft Maintenance Squadron crew chief, prepares to fill a Boeing E-3 Sentry aircraft with liquid nitrogen after supporting exercise Astral Knight 20 at Ramstein Air Base, Germany, Sept. 24, 2020. The E-3 Sentry’s life support system is reinforced by liquid nitrogen. AK20 is a biennial integrated air and missile defense (IAMD) exercise focused on incrementally developing a theater wide joint IAMD architecture. (U.S. Air Force photo by Senior Airman Milton Hamilton)