Screen Shot 2016-06-07 at 18.36.58 Published on June 7, 2016 in North American Aviation, Inc., X-15A Hypersonic Research RocketplaneFull resolution (1016 × 796) ← Previous Next → A rear view of an X-15 parked on the dry lake bed at Edwards Air Force base shows the two four-chamber XLR11-RM-5 rocket engines. (NASA image E-5256)