Lockheed NF-104A

The Lockheed NF-104A was an American mixed power, high-performance, supersonic aerospace trainer that served as a low-cost astronaut training vehicle for the X-15 and projected X-20 Dyna-Soar programs.

Three aircraft were modified from existing Lockheed F-104A airframes and served with the Aerospace Research Pilots School between 1963 and 1971, the modifications included a small supplementary rocket engine and a reaction control system for flight in the upper atmosphere. During the test program the maximum altitude reached was over 120,000 ft (36,600 m). One of the aircraft was destroyed in an accident while being flown by Chuck Yeager. The accident was depicted in the book The Right Stuff and the film of the same name.