Mark Pestana Art 1 X-15 Into SpaceThe North American X-15 was a hypersonic rocket-powered aircraft operated by the USAF and NASA in the 1960s. Three X-15s set speed and altitude records, returning valuable data used in aircraft and spacecraft design, and set records for the highest speed by a manned, powered aircraft – 4,520 miles per hour. Thirteen flights by eight pilots met the Air Force “astronaut” criterion by exceeding an altitude of 50 miles. They are Robert White, Joe Walker, Robert Rushworth, John McKay, Bill Dana, Pete Knight, Michael Adams, and Joe Engle, who is the only X-15 pilot to also fly the Space Shuttle. The other test pilots who flew the X-15 are Neil Armstrong, Scott Crossfield, Forrest Petersen, and Milt Thompson.