An F-35A Lightning II takes off to complete the final test exercise of the nuclear design certification process at Nellis Air Force Base, Nevada, Sept. 21, 2021 . Test pilots flew to the Tonopah Test Range at Nellis AFB and released two B61-12 Joint Test Assemblies from operationally realistic flight envelopes. (U.S. Air Force photo by Airman 1st Class Zachary Rufus)