Scaled Composites Stratolaunch

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2018-01-28 Stratolaunch Aircraft.png
The aircraft during a taxi test in 2018
Role Space launch carrier
National origin United States
Manufacturer Scaled Composites
First flight April 13, 2019[1]
Introduction planned 2020[2]
Status In development
Primary user Stratolaunch Systems
Other name(s) Roc
Registration N351SL
First flight April 13, 2019
Aircraft carried Pegasus (proposed)
Dream Chaser (proposed)

The Scaled Composites Model 351 Stratolaunch is an aircraft built for Stratolaunch Systems by Scaled Composites to carry air-launch-to-orbit rockets. It was announced in December 2011 and rolled out in May 2017.[1] The twin-fuselage design is the aircraft with the longest wingspan ever flown at 385 feet (117 m), surpassing the Hughes H-4 Hercules flying boat's of 320 feet 11 inches (97.82 m). The Stratolaunch is intended to carry a 550,000-pound (250,000 kg) payload and has a 1,300,000-pound (590,000 kg) maximum takeoff weight. The aircraft first flew on April 13, 2019.


In early 2011, Dynetics began studying the project and had approximately 40 employees working on it at the December 2011 public announcement. Stratolaunch originally planned to airlaunch the Falcon 9 Air by SpaceX, whose efforts began shortly before December.[3] Launching medium-sized payloads with the Falcon 9 dictated the aircraft size but SpaceX departed a year later.[4]

In May 2012, its specially constructed hangar was being built at the Mojave Air and Space Port in Mojave, California.[5] In October 2012, the first of two manufacturing buildings, a 88,000 sq ft (8,200 m2) facility for construction of the composite sections of the wing and fuselage, was opened for production.[6]

In August 2013, the Pegasus II was selected for the air launch vehicle.[7] In August 2014, all solid-fuel propulsion was selected, rather than liquid-fuel for the Orbital Sciences launcher.[8] In August 2015, 200,000 lb (91 t) of structure was assembled.[9]

By June 2016 Scaled Composites had 300 people working on the project.[10] Virgin Galactic also plans to air launch small satellites with the LauncherOne from a 747.[11] Orbital ATK dropped its Thunderbolt rocket project for medium-class payloads.[4] In October 2016, the Pegasus II was replaced by multiple Pegasus XL mounted underneath the carrier aircraft, developments of the original Pegasus rocket which had been launched 42 times since 1990.[12]


By May 1, 2017, Stratolaunch had already spent hundreds of millions of dollars on the project.[4] On May 31, 2017, the aircraft was rolled out for fueling tests, and to be prepared for ground testing, engine runs, taxi tests, and ultimately first flight, on track for a 2019 first launch demonstration.[13] By then, it may have competition from the DARPA XS-1 or from Vector Space Systems.[14] By September 2017, engine testing was underway as well as testing of "control surfaces and electric, pneumatic and fire detection systems."[15] In December 2017, its first low-speed taxi test took it to 25 knots (46 km/h) on the runway powered by its six turbofans to test its steering, braking, and telemetry.[16] Higher-speed taxi tests began in 2018, reaching 40 knots (74 km/h) in February,[17] and 78 kn (140 km/h) in October.[18] On January 9, 2019, Stratolaunch completed a 110 knot (219 km/h) taxi test, and released a photograph of the nose landing gear lifted off the ground during the test.[19]

In January 2019, three months after the death of Stratolaunch founder and Microsoft co-founder Paul Allen, Stratolaunch abandoned the development of its PGA rocket engines and dedicated launchers. This left the Northrop Grumman Pegasus XL as the sole launch option for an orbital capability of 800 lb (360 kg). Stratolaunch was then aiming for a first flight within a few weeks and a first launch from the carrier in 2020.[2]

The aircraft first flew on April 13, 2019, at the Mojave Air and Space Port, reaching 17,000 ft (5,200 m) and 165 kn (305 km/h) in a 2 h 29 min flight.[20] Its future has been in doubt since the death of company founder Paul Allen and Stratolaunch Systems could cease operations.[21]


In June 2019 the Stratolaunch was put up for sale by Vulcan for $400 million.[22]


Stratolaunch has a twin-fuselage configuration, each 238 ft (73 m) long and supported by 12 main landing gear wheels and two nose gear wheels, for a total of 28 wheels.[13] The twin-fuselage configuration is similar to the Scaled Composites White Knight Two.[10] Each fuselage has its own empennage.[23]

The pilot, co-pilot and flight engineer are accommodated in the right fuselage cockpit, while the left fuselage cockpit is empty and unpressurized.[24] The flight data systems are in the left fuselage.[25][26]

At 385 ft (117 m), it is the largest plane by wingspan, longer than a 360 ft (110 m) American football field.[13] The center section of the high-mounted, high aspect ratio wing is fitted with a Mating and Integration System (MIS), developed by Dynetics and capable of handling a 490,000 lb (220 t) load.[27]

Stratolaunch is powered by six Pratt & Whitney PW4056 engines positioned on pylons outboard of each fuselage,[28] providing 56,750 lbf (252.4 kN) of thrust per engine.[29] Many of the aircraft systems have been adopted from the Boeing 747-400, including the engines, avionics, flight deck, landing gear and other systems, reducing development costs.[3]

It will require 12,000 ft (3,700 m) of runway to lift-off.[3] It should release its rocket at 35,000 ft (11,000 m).[24] It will carry a 550,000 lb (250 t) payload.[4] With a Pegasus II, it could deliver up to 13,500 lb (6.1 t) satellites to LEO or 4,500 lb (2.0 t) to a 15° GTO.[6] It could launch a Dream Chaser small spaceplane capable of transporting astronauts or payloads within 24 hours.[30][31] The stated goal is to carry up to three Orbital ATK "Pegasus XL" rockets for high-altitude launches by 2022.[32][33]

Within Scaled Composites, its model number is M351.[34] It is nicknamed "Roc" after Sinbad's Roc, the mythical bird so big it could carry an elephant.[24]

Specifications (Model 351 Stratolaunch)[edit]

An illustration comparing the size of four large aircraft: Hughes H-4 Hercules (Spruce Goose), Antonov An-225 Mriya, Airbus A380, Boeing 747-8, and Scaled Composites Stratolaunch
Comparison between five of the largest aircraft:
  Scaled Composites Stratolaunch

Data from Stratolaunch[28]

General characteristics

  • Length: 238 ft (73 m) [13]
  • Wingspan: 385 ft (117 m) [13]
  • Height: 50 ft (15 m) [13]
  • Empty weight: 500,000 lb (226,796 kg) [13]
  • Gross weight: 750,000 lb (340,194 kg) with no external payload[13]
  • Max takeoff weight: 1,300,000 lb (589,670 kg) [13]
  • External payload: 550,000 lb (250,000 kg)[13]
  • Powerplant: 6 × Pratt & Whitney PW4056 turbofan, 56,750 lbf (252.4 kN) thrust each [29]
  • Maximum speed: 461 kn; 853 km/h (530 mph) [9]
  • Range: 1,000 nmi (1,151 mi; 1,852 km) radius[35]
  • Ferry range: 2,500 nmi (2,877 mi; 4,630 km) [6]

See also[edit]

Related development

Aircraft of comparable role, configuration and era

Related lists


  1. ^ a b "Stratolaunch airborne in first flight of world's largest aircraft". Flightglobal. April 13, 2019.
  2. ^ a b Guy Norris (January 19, 2019). "Stratolaunch Terminates Rocket Engine and Launcher Programs". Aviation Week Network.
  3. ^ a b c Michael Mecham and Frank Morring, Jr. (December 19, 2011). "Allen Places Big Bet On Air Launches". Aviation Week & Space Technology.
  4. ^ a b c d Foust, Jeff (May 31, 2017). "Stratolaunch rolls out giant aircraft". SpaceNews.
  5. ^ Doug Messier (May 5, 2012). "Space Goose's Nest Grows in the Mojave". Parabolic Arc.
  6. ^ a b c Chris Bergin (May 24, 2013). "Stratolaunch and Orbital – The Height of Air Launch".
  7. ^ ATK (August 12, 2013). "ATK Gets Contract for Stratolaunch Propulsion System" (Press release).
  8. ^ Amy Butler (November 6, 2014). "Stratolaunch Drops Liquid Stage From Rocket System". Aviation Week Network.
  9. ^ a b Jason Silverstein (February 26, 2015). "SEE IT: World's largest plane under construction in Calif". NY Daily News.
  10. ^ a b Gates, Dominic (June 19, 2016). "Paul Allen's giant plane takes shape in the desert, but its market is unclear". Seattle Times.
  11. ^ Christian Davenport (June 20, 2016). "Why Microsoft co-founder Paul Allen is building the world's largest airplane". Washington Post.
  12. ^ Stephen Clark (October 10, 2016). "Stratolaunch announces plan to fly with Pegasus rockets". Spaceflight Now.
  13. ^ a b c d e f g h i j "Stratolaunch Aircraft Makes First Rollout To Begin Fueling Tests" (Press release). Stratolaunch. May 31, 2017. Archived from the original on June 1, 2017. Retrieved April 14, 2019.
  14. ^ Sharwood, Simon (June 1, 2017). "Microsoft founder Paul Allen reveals world's biggest-ever plane". The Register.
  15. ^ Foust, Jeff (September 19, 2017). "Engine test latest step for Stratolaunch's giant aircraft". SpaceNews.
  16. ^ "Stratolaunch Completes First Low-Speed Taxi Test" (Press release). Stratolaunch. December 18, 2017.
  17. ^ Baylor, Michael (February 26, 2018). "Stratolaunch conducts high-speed taxi tests on giant carrier aircraft". Retrieved February 27, 2018.
  18. ^ Wall, Mike (October 29, 2018). "Stratolaunch's Rocket Carrier, the Biggest Airplane Ever Built, Aces Fastest Runway Test Yet". Retrieved November 2, 2018.
  19. ^ Alan Boyle (January 9, 2018). "Stratolaunch gets world's biggest airplane ready for takeoff with 136 mph taxi test". Geekwire. Retrieved January 10, 2018.
  20. ^ "Stratolaunch becomes world's largest aircraft to fly". Flightglobal. April 13, 2019.
  21. ^ "Exclusive: Space firm founded by billionaire Paul Allen closing…". Reuters. June 1, 2019.
  22. ^ "The world's largest airplane is up for sale for $400 million". June 14, 2019.
  23. ^ Jeff Foust (June 20, 2016). "Inside Stratolaunch". SpaceNews.
  24. ^ a b c Dominic Gates (May 31, 2017). "Paul Allen's colossal Stratolaunch plane emerges from its lair". Seattle Times.
  25. ^ Tulis, David (December 19, 2017). "Scaled Composites-designed Stratolaunch taxis". Aircraft Owners and Pilots Association. Retrieved April 15, 2019.
  26. ^ Masunaga, Samantha (June 20, 2016). "The Stratolaunch is huge, but it's not the strangest aircraft ever built in Southern California". Los Angeles Times. Retrieved April 15, 2019.
  27. ^ Stratolaunch Systems (December 13, 2011). "Paul G. Allen Announces Revolution in Space Transportation" (PDF). National Space Society. p. 10.
  28. ^ a b "Get the Latest From Stratolaunch". Stratolaunch. Retrieved April 17, 2019.
  29. ^ a b "Type Certificate Number E24NE data sheet" (PDF). FAA. November 23, 2015.
  30. ^ Dickerson, Kelly (October 6, 2014). "Private Dream Chaser Space Plane May Launch from Giant Aircraft". Retrieved April 15, 2019.
  31. ^ Whitfield, Bethany (October 2, 2014). "Dream Chaser Teams with Stratolaunch to Carry People into Space". Flying Magazine. Retrieved April 15, 2019.
  32. ^ "The World's Largest Plane's First Flight From Every Angle". Popular Mechanics. April 15, 2019. Retrieved April 15, 2019. The tests come after a long series of taxi tests that always stopped just short of acheiving actual flight, but now that threshold has been crossed, and the engineers seem pleased with the results.
  33. ^ "STRATOLAUNCH, THE WORLD'S BIGGEST AIRPLANE, TAKES FLIGHT". Condé Nast Wired. April 13, 2019. Retrieved April 15, 2019. eight years in the making. By 2022, the company hopes to use the twin-fuselage, six-engined, catamaran-style aircraft to launch satellite-bearing rockets into space.
  34. ^ "Projects". Scaled Composites.
  35. ^ Paul G. Allen (June 20, 2016). "Tackling the Space Challenge". LinkedIn.

External links[edit]