On This Day in History / August 22, 2024 1963: Above Edwards AFB, NASA test pilot Joseph A. Walker flew the X-15 to new records of 354,000 feet (67 miles) in altitude and 3,614 MPH. It was Walker’s last X-15 free flight and the highest altitude achieved during the X-15 program. (Image of Walker in X-15 under B-52 mothership)