Encyclopedia Astronautica
X-15A-2



x15a2.jpg
X-15A-2
Credit: NASA
x15ablat.jpg
X-15 ablative coat
X-15A-2 ablative coating
Credit: NASA
x15delta.jpg
X15 Delta
American manned spaceplane. Study 1965. The crash-damaged X-15 number 2 was rebuilt to attain even higher speeds. The body frame was stretched, and two drop tanks were added, increasing propellant load by 75%.

An ablative heat shield was applied to protect the spaceplane during re-entry. The X-15A-2 reached the highest speeds and altitudes of any manned spaceplane until the space shuttle entered service.

The X-15A-2, modified from the number two aircraft and delivered to NASA in February 1964, included among other new features, a 28-in. fuselage extension to carry liquid hydrogen for a supersonic combustion ramjet that was flown (as a dummy) but never tested. It also had external tanks for liquid ammonia and liquid oxygen. These tanks provided roughly 60 seconds of additional engine burn and were used on the aircraft's Mach 6.7 flight. While adding to the speed the X-15 did achieve, the tanks also increased the aircraft's weight to almost 57,000 lb and added significantly to the drag experienced by the aircraft in flight.

700 hours was needed to refurbish the heat shield. The ablative covering had to be completely stripped off, then reapplied. After the record Mach 6.93 flight, the aircraft received thermal structural damage and the covering was severely pitted and charred. Repair was uneconomical and the aircraft was grounded.

Characteristics

Crew Size: 1. Spacecraft delta v: 2,020 m/s (6,620 ft/sec).

Gross mass: 25,455 kg (56,118 lb).
Unfuelled mass: 8,317 kg (18,335 lb).
Height: 16.00 m (52.00 ft).
Span: 6.80 m (22.30 ft).
Thrust: 262.45 kN (59,000 lbf).
Specific impulse: 276 s.

More... - Chronology...


Associated Countries
Associated Engines
  • XLR99 Thiokol Lox/Ammonia rocket engine. 262.4 kN. Out of production. Isp=276s. The first large, man-rated, throttleable, restartable liquid propellant rocket engine, boosted the X-15A. First flight 1959. More...

See also
Associated Manufacturers and Agencies
  • USAF American agency overseeing development of rockets and spacecraft. United States Air Force, USA. More...
  • North American American manufacturer of rockets, spacecraft, and rocket engines. North American, Palmdale, El Segundo. Downey, CA, USA More...

Associated Propellants
  • Lox/Ammonia Liquid oxygen was the earliest, cheapest, safest, and eventually the preferred oxidiser for large space launchers. Its main drawback is that it is moderately cryogenic, and therefore not suitable for military uses where storage of the fuelled missile and quick launch are required. Ammonia (NH3) is a colourless gas and liquid with a strong irritating characteristic odour. More...

Bibliography
  • Guenther, Ben, Miller, Jay, and Panopalis, Terry,, North American X-15/X-15A-2, Aerofax, Arlington, Texas, 1985.
  • Jenkins, Dennis R,, Space Shuttle: The History of the National Space Transportation System : The First 100 Missions, Third edition, Voyageur Press, 2001.
  • Miller, Ron, The Dream Machines, Krieger, Malabar, Florida, 1993.
  • Zhelyez x-plane book,
  • NASA Dryden Flight Research Center Web Site, Web Address when accessed: here.
  • NASA Report, Thermal protection system X-15A-2 Design report, Web Address when accessed: here.

X-15A-2 Chronology


1964 February - .
  • The X-15A-2 delivered to NASA - . Nation: USA. Spacecraft: X-15A-2. The X-15A-2, modified from the number two aircraft, included among other new features, a 28-in. fuselage extension to carry liquid hydrogen for a supersonic combustion ramjet that was flown (as a dummy) but never tested. It also had external tanks for liquid ammonia and liquid oxygen. These tanks provided roughly 60 seconds of additional engine burn and were used on the aircraft's Mach 6.7 flight.

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