When Mark Lewis walked into the Pentagon in late 2019, he thought his most important job as a leading research official would be overseeing the development of new, high-speed missiles. The veteran aerospace scientist and former Air Force official was rejoining the Defense Department as it sought to regain the advantage from China in developing fast-flying "hypersonic" weapons. The year before, DOD's research chief had called it his top priority . But on his first day back, Lewis had a...
