The Martin Marietta X-24B was an experimental US aircraft developed from a joint USAF-NASA program named PILOT(1963–1975). It was designed and built to test lifting body concepts, experimenting with the concept of unpowered reentry and landing, later used by the Space Shuttle. The X-24 was drop launched from a modified B-52 Stratofortress at high altitudes before igniting its rocket engine; after expending its rocket fuel, the pilot would glide the X-24 to an unpowered landing.
The X-24 was one of a group of lifting bodies flown by the NASA Flight Research Center (now Dryden Flight Research Center) in a joint program with the U.S. Air Force at Edwards Air Force Base in California from 1963 to 1975. The lifting bodies were used to demonstrate the ability of pilots to maneuver and safely land wingless vehicles designed to fly back to Earth from space and be landed like an airplane at a predetermined site.
The X-24B's design evolved from a family of potential reentry shapes, each with higher lift-to-drag ratios, proposed by the Air Force Flight Dynamics Laboratory. To reduce the costs of constructing a research vehicle, the Air Force returned the X-24A to the Martin Marietta Corporation (as Martin Aircraft Company became after a merger) for modifications that converted its bulbous shape into one resembling a "flying flatiron" -- rounded top, flat bottom, and a double delta planform that ended in a pointed nose.
First to fly the X-24B was John Manke, in a glide flight on 1 August 1973. He was also the pilot on the first powered mission, on 15 November 1973
The X-24B made two precise landings on the main concrete runway at Edwards which showed that accurate unpowered reentry vehicle landings were operationally feasible. Pilots on these missions would fly steep descents and then perform a "flare out" maneuver at high speeds to make a 200 mph landing, simulating the landing speed and approach pattern of the Space Shuttle orbiter.These missions, flown by Manke and Air Force Maj. Mike Love, represented the final milestone in a program that helped write the flight plan for the NASA Space Shuttle program.
Top speed achieved by the X-24B was 1,164 mph (1873 km/h), and the highest altitude it reached was 74,130 feet (22.59 km). The pilot on the last powered flight of the X-24B was Bill Dana, who also flew the last X-15 flight about seven years earlier.
The X-24B was the last aircraft to fly in Dryden's Lifting Body program. The X-24B was flown 36 times.
The X-24B is on public display at the National Museum of the United States Air Force, Wright-Patterson AFB, Ohio.
