U.S. Air Force Airman 1st Class Sondra Saul, 20th Equipment Maintenance Squadron aircraft metals technician apprentice, fills a bucket with liquid nitrogen in the metal shop at Shaw Air Force Base, S.C., Nov. 30, 2018. Liquid nitrogen is used to freeze aircraft pieces tightly together. (U.S. Air Force photo by Airman 1st Class Kaitlyn Brewer)