Martin-Marietta X-23

X-23 PRIME
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Preserved X-23 PRIME at USAF Museum, Dayton, Ohio
Type	Lifting body
Manufacturer	Martin Marietta
Maiden flight	21 December 1966
Retired	19 April 1967
Status	Out of service
Primary user	United States Air Force
Number built	3
Variants	Martin X-24

The Martin Marietta X-23A PRIME (Precision Reentry Including Maneuvering reEntry) was a small lifting body re-entry vehicle tested by the United States Air Force in the mid-1960s. Unlike ASSET, primarily used for structural and heating research, the X-23 PRIME was developed to study the effects of maneuvering during re-entry, including cross-range maneuvers up to 710 statute miles (1143 km) off the ballistic track.

Design

Each X-23 was constructed from titanium, beryllium, stainless steel, and aluminium "where appropriate". The craft consisted of two sections — the aft main structure and a removable forward "glove section". The structure was completely covered with a Martin-developed ablative heat shield 20 to 70 mm (¾ to 2¾ inches) thick, though the nose cap was constructed of carbon-phenolic.

Aerodynamic control was provided by a pair of 12-inch (30 cm) square lower flaps, and fixed upper flaps and rudders. A nitrogen gas reaction control system was used outside the atmosphere. At Mach 2 a drogue ballute deployed and slowed the vehicle's descent. As it deployed, its cable sliced the upper structure of the main equipment bay, allowing a 47-foot (16.4 m) recovery chute to deploy. It would then be recovered by a specially-equipped JC-130B Hercules.

Flight testing

The first PRIME vehicle was launched from Vandenberg AFB on 21 December 1966 atop an Atlas launch vehicle. This mission simulated a low-earth orbit reentry with a zero cross-range. The ballute deployed at 99,850 feet (30.43 km), though the recovery parachute failed to completely deploy. The vehicle crashed into the Pacific.

The second was launched on 5 March 1967. This flight simulated a 654-mile (1053 km) cross range re-entry, and banking at hypersonic speeds. Several stringers on the main parachute failed to cut, preventing a successful recovery. It too was lost in the Pacific.

The final PRIME mission was flown on 19 April 1967, and simulated reentry from low-earth orbit with a 710 mile (1143 km) cross-range. This time, all systems performed perfectly, and the X-23 was successfully recovered. An inspection by a USAF-Martin team reported the craft "ready to fly again", although no later missions were carried out. The third X-23 is now on display at the National Museum of the United States Air Force at Wright-Patterson Ohio.

Specifications (X-23)

General characteristics

• Crew: None
• Length: 6 ft 9 in (2.07 m)
• Wingspan: 3 ft 10 in (1.16 m)
• Height: 2 ft 1 in (0.64 m)
• Loaded weight: 890 lb (405 kg)
• Powerplant: × Nitrogen-gas reaction control thrusters

Performance

• Maximum speed: Mach 25
• Range: 710 miles (1,143 km)
• Hypersonic L/D Ratio: 1:1

See also

Comparable aircraft
Molniya BOR-4
ASSET Designation sequence
X-20 - X-21 - X-22 - X-23 - X-24 - X-25 - X-26

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Martin-Marietta X-23".