X-15A-2
X-15A-2
Credit - NASA
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Class: Manned. Type: Spaceplane. Destination: Suborbital. Nation: USA. Agency: USAF. Manufacturer: North American.

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.

Crew Size: 1. Length: 16.00 m (52.00 ft). Span: 6.80 m (22.30 ft). Mass: 25,455 kg (56,118 lb). Main Engine: XLR-99. Main Engine Thrust: 262.445 kN (59,000 lbf). Main Engine Propellants: Lox/Ammonia. Main Engine Propellants: 17,138 kg (37,782 lb). Main Engine Isp: 276 sec. Spacecraft delta v: 2,020 m/s (6,620 ft/sec). Electrical System: Batteries.


X-15A-2 Chronology
  • 1964 August 14 - X-15A-2 Stability Test mission - Program: X-15. Crew: Rushworth. Launch Site: Edwards. Launch Vehicle: X-15A-2. FAILURE: Nose gear deployed at Mach 4.2. Apogee: 31 km (19 mi).

    Maximum Speed - 5776 kph. Maximum Altitude - 31486 m. Nose landing gear extended at Mach 4.5. Both tires blew on landing.

  • 1964 February 1 - The X-15A-2 delivered to NASA -

    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.

  • 1964 June 25 - X-15A-2 Stability Test mission - Program: X-15. Crew: Rushworth. Launch Site: Edwards. Launch Vehicle: X-15A-2. Apogee: 25 km (15 mi).

    Maximum Speed - 4994 kph. Maximum Altitude - 25390 m. First flight of X-15 No. 2 in X-15A-2 configuration, but without drop tanks.

  • 1964 November 30 - X-15A-2 Gear mod, Stab,ST Test mission - Program: X-15. Crew: McKay. Launch Site: Edwards. Launch Vehicle: X-15A-2. Apogee: 26 km (16 mi).

    Maximum Speed - 4970 kph. Maximum Altitude - 26579 m.

  • 1964 September 29 - X-15A-2 Stab.,Star tracker Test mission - Program: X-15. Crew: Rushworth. Launch Site: Edwards. Launch Vehicle: X-15A-2. FAILURE: Nose gear scoop door causes handling difficulties. Apogee: 29 km (18 mi).

    Maximum Speed - 5699 kph. Maximum Altitude - 29809 m.

  • 1965 April 28 - X-15A-2 Landing loads,Stab Test mission - Program: X-15. Crew: McKay. Launch Site: Edwards. Launch Vehicle: X-15A-2. Apogee: 28 km (17 mi).

    Maximum Speed - 5266 kph. Maximum Altitude - 28224 m. First star tracker checkout.

  • 1965 August 3 - X-15A-2 RAS,ST,Landing Test mission - Program: X-15. Crew: Rushworth. Launch Site: Edwards. Launch Vehicle: X-15A-2. Apogee: 63 km (39 mi).

    Maximum Speed - 5796 kph. Maximum Altitude - 63612 m.

  • 1965 February 17 - X-15A-2 Stability Test mission - Program: X-15. Crew: Rushworth. Launch Site: Edwards. Launch Vehicle: X-15A-2. FAILURE: Landing skid extends at Mach 4.3. Apogee: 29 km (18 mi).

    Maximum Speed - 5649 kph. Maximum Altitude - 28986 m. Right main landing gear extended at Mach 4.1; normal landing.

  • 1965 July 8 - X-15A-2 ST,Landing,Alt Test mission - Program: X-15. Crew: McKay. Launch Site: Edwards. Launch Vehicle: X-15A-2. Apogee: 64 km (39 mi).

    Maximum Speed - 5887 kph. Maximum Altitude - 64800 m. Star tracker mission to photograph Gamma Cassiopeia.

  • 1965 June 22 - X-15A-2 Stability,ST,gear Test mission - Program: X-15. Crew: McKay. Launch Site: Edwards. Launch Vehicle: X-15A-2. Apogee: 47 km (29 mi).

    Maximum Speed - 6336 kph. Maximum Altitude - 47518 m.

  • 1965 May 18 - X-15A-2 Stab, landing, ST Test mission - Program: X-15. Crew: McKay. Launch Site: Edwards. Launch Vehicle: X-15A-2. Apogee: 31 km (19 mi).

    Maximum Speed - 5697 kph. Maximum Altitude - 31120 m.

  • 1965 November 3 - X-15A-2 External Tank Test mission - Program: X-15. Crew: Rushworth. Launch Site: Edwards. Launch Vehicle: X-15A-2. Apogee: 21 km (13 mi).

    First flight with empty external tanks. Ammonia tank recovered; Lox tank destroyed. Maximum Speed - 2414 kph. Maximum Altitude - 21520 m.

  • 1965 September 22 - X-15A-2 Infrared Scanner test mission - Program: X-15. Crew: McKay. Launch Site: Edwards. Launch Vehicle: X-15A-2. Apogee: 30 km (18 mi).

    Maximum Speed - 5744 kph. Maximum Altitude - 73091 m.

  • 1966 August 12 - X-15A-2 ST,Pitot,Base drag Test mission - Program: X-15. Crew: Knight. Launch Site: Edwards. Launch Vehicle: X-15A-2. Apogee: 70 km (43 mi).

    Maximum Speed - 5586 kph. Maximum Altitude - 70440 m.

  • 1966 August 3 - X-15A-2 ST, Base drag Test mission - Program: X-15. Crew: Knight. Launch Site: Edwards. Launch Vehicle: X-15A-2. Apogee: 75 km (46 mi).

    Maximum Speed - 5535 kph. Maximum Altitude - 75890 m. UV photos of stars in Auriga.

  • 1966 August 30 - X-15A-2 V-On,Maurer,TPS Test/Technology/Ultraviolet Astronomy mission - Program: X-15. Crew: Knight. Launch Site: Edwards. Launch Vehicle: X-15A-2. FAILURE: SAS system drops out repeatedly, hydrogen peroxide fire in ventral fin. Apogee: 31 km (19 mi).

    Maximum Speed - 5701 kph. Maximum Altitude - 30540 m.

  • 1966 July 1 - X-15A-2 External Tank Test mission - Program: X-15. Crew: Rushworth. Launch Site: Edwards. Launch Vehicle: X-15A-2. FAILURE: Erroneous failure indication results in emergency landing at Mud Lake. Apogee: 13 km (8 mi).

    First flight with fueled external tanks. Engine shutdown at 34.6 seconds due to fuel flow anomalies. Maximum Speed - 1646 kph. Maximum Altitude - 13720 m.

  • 1966 July 21 - X-15A-2 Alt,ST,Abl TPS Test mission - Program: X-15. Crew: Knight. Launch Site: Edwards. Launch Vehicle: X-15A-2. Apogee: 58 km (36 mi).

    Maximum Speed - 5741 kph. Maximum Altitude - 58610 m.

  • 1966 May 18 - X-15A-2 V-On Stab Test mission - Program: X-15. Crew: Rushworth. Launch Site: Edwards. Launch Vehicle: X-15A-2. Apogee: 30 km (18 mi).

    Maximum Speed - 5936 kph. Maximum Altitude - 30170 m.

  • 1966 November 18 - X-15A-2 Test mission - Program: X-15. Crew: Knight. Launch Site: Edwards. Launch Vehicle: X-15A-2. FAILURE: Failure. Apogee: 14 km (8 mi).

    Unofficial world's speed record. Maximum Speed - 6838 kph. Maximum Altitude - 30140 m.

  • 1967 August 21 - X-15A-2 Ramjet/Hycon/TPS Test/Imaging mission? - Program: X-15. Crew: Knight. Launch Site: Edwards. Launch Vehicle: X-15A-2. Apogee: 27 km (16 mi).

    First test with full ablative coating, ramjet pod. Maximum Speed - 5419 kph. Maximum Altitude - 27740 m.

  • 1967 May 8 - X-15A-2 Ramjet flow Test mission - Program: X-15. Crew: Knight. Launch Site: Edwards. Launch Vehicle: X-15A-2. FAILURE: Eyelid installed on one window; other window fogs up. Apogee: 29 km (18 mi).

    Maximum Speed - 5138 kph. Maximum Altitude - 29750 m. Check out of stability and control with ramjet pod.

  • 1967 October 3 - X-15A-2 TPS/Ramjet/Mach 6.7 Test mission - Program: X-15. Crew: Knight. Launch Site: Edwards. Launch Vehicle: X-15A-2. FAILURE: Heat flow from dummy ramjet nearly burns tail off. Apogee: 31 km (19 mi).

    Unofficial world speed record (full ablative coating, dummy ramjet, mechanical eyelid). Maximum Speed - 7273 kph. Maximum Altitude - 31120 m.


Bibliography and Further Reading
  • Guenther, Ben, Miller, Jay, and Panopalis, Terry,, North American X-15/X-15A-2, Aerofax, Arlington, Texas, 1985. ISBN: 0942548345. Comprehensive and technically excellent account of the X-15 program. More at amazon.com...
  • Jenkins, Dennis R,, Space Shuttle: The History of the National Space Transportation System : The First 100 Missions, Third edition, Voyageur Press, 2001. ISBN: 0963397451. Excellent - the most comprehensive account of the design, development, and flights of the space shuttle.Takes the reader from the maze of designs during the first shuttle competition to future plans. More at amazon.com...
  • Zhelyez x-plane book, .
  • Thompson, M, The Edge of Space, (via Jonathon McDowell).
  • Miller, Ron, The Dream Machines, Krieger, Malabar, Florida, 1993. ISBN: 0894640399. Sensational chronological roundup of text, photos, and sketches of virtually every spacecraft and launch vehicle design every conceived but never built. A gold mine for space-struck baby boomers. More at amazon.com...
 
 
 
 
 
 
 
 
 

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