From left, Tim Shields, a senior engineer with Mechanical Solutions, Inc., and Richard Roth, a research engineer with Etegent Technologies, Ltd., set up equipment to conduct sensor validation testing using a General Electric F404 engine test in the Arnold Engineering Development Complex Sea Level Test Cell 1 at Arnold Air Force Base, Tenn., June 15, 2021. (U.S. Air Force photo by Jill Pickett) (This image has been altered by obscuring badges and a screen for security purposes.)