Seven Hroncich, left, an instrument technician, Robert Bradford, center right, an electrician, Kevin Thompson, right, test operations engineer, Tim Mullins, an outside machinist, and others prepare for a test run in the Arnold Engineering Development Complex (AEDC) Arcs Test Facility Control Room, May 5, 2020, at Arnold Air Force Base, Tenn. The Arcs Facility provides aerothermal ground test simulations of hypersonic flight over a wide range of velocities and pressure altitudes in support of materials and structures development. Team members are maintaining social distancing when possible and wearing masks when not so they can continue the critical national defense mission of AEDC. (U.S. Air Force photo by Jill Pickett) (This image was altered by obscuring items for security purposes.)