Scaled Composites Stratolaunch
|Stratolaunch carrier aircraft|
|Role||Space launch carrier|
|National origin||United States|
|Primary user||Stratolaunch Systems|
The Scaled Composites Stratolaunch is an aircraft being 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; its first launch demonstration is scheduled for 2019. The twin-fuselage design is the largest by wingspan, could carry a 550,000 lb (250 t) payload for a 1,300,000 lb (590 t) maximum take-off weight.
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. Launching medium-sized payloads with the Falcon 9 dictated the aircraft size but SpaceX departed a year later.
In May 2012, its specially-constructed hangar was being built in Mojave Air and Space Port. 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.
In August 2013, the Pegasus II was selected for the air launch vehicle. In August 2014, all solid-fuel propulsion was preferred to liquid-fuel for the Orbital Sciences launcher. In August 2015, 200,000 lb (91 t) of structure was assembled.
By June 2016 Scaled Composites had 300 people working on the project. Virgin Galactic also plans to air launch small satellites with the LauncherOne from a 747. Orbital ATK dropped its Thunderbolt rocket project for medium-class payloads. 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.
On May 1, 2017, Stratolaunch already had spent hundreds of millions of dollars on the project. On May 31, 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. By then, it may have competition from the DARPA XS-1 or from Vector Space Systems. By September, engine testing was underway as well as testing of "control surfaces and electric, pneumatic and fire detection systems." In December, 2017, its first low-speed taxi test took it to 25 knots (46 km/h) powered on the runway by its six turbofans, to test its steering, braking, and telemetry. It began higher-speed taxi tests in 2018, reaching 40 knots (74 km/h) in February. It reached 78 kn (140 km/h) in October of that year. On January 9, 2019, Stratolaunch completed a 110 knot (219 km/h) taxi test, and released an accompanying photo of the nose landing gear lifted off the ground during the test. 
Three months after the death of Stratolaunch founder Paul Allen, Stratolaunch abandoned the development of its PGA rocket engines and dedicated launchers in January 2019. 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.
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. The twin-fuselage configuration is similar to the Scaled Composites White Knight Two. Each fuselage has its own empennage with horizontal and vertical stabilizers, leaving a clear area behind the payload to reduce the risk of interference during flight.
At 385 ft (117 m), it is the largest plane by wingspan, to be compared to a 360 ft (110 m) American football field. The centre section of the high-mounted, high aspect ratio wing is fitted with a Mating and Integration System (MIS) capable of handling a 500,000 lb (230 t) load, being developed by Dynetics.
Stratolaunch is powered by six Pratt & Whitney PW4056 engines positioned on pylons outboard of each fuselage, 56,750 lbf (252.4 kN) each. To cut development costs, many of the aircraft systems have been adopted from the Boeing 747-400, including the engines, avionics, flight deck, landing gear and other systems.
It will require 12,000 ft (3,700 m) of runway to lift-off. It should release its rocket at 35,000 ft (11,000 m). It will carry a 550,000 lb (250 t) payload. 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. It could launch a Dream Chaser small space shuttle capable of return astronauts or payloads within 24 hours.
Specifications (Stratolaunch Systems Carrier)
Data from Stratolaunch
- Length: 238 ft (73 m)
- Wingspan: 385 ft (117 m)
- Height: 50 ft (15 m)
- Empty weight: 500,000 lb (226,796 kg) 
- Gross weight: 750,000 lb (340,194 kg) with no external payload
- Max takeoff weight: 1,300,000 lb (589,670 kg)
- external payload: 550,000 lb (250,000 kg)
- Powerplant: 6 × Pratt & Whitney PW4056 turbofan, 56,750 lbf (252.4 kN) thrust each 
- Maximum speed: 461 kn; 853 km/h (530 mph) 
- Range: 1,000 nmi (1,151 mi; 1,852 km) radius
- Ferry range: 2,500 nmi (2,877 mi; 4,630 km) 
Aircraft of comparable role, configuration and era
- "Stratolaunch Aircraft Makes First Rollout To Begin Fueling Tests" (Press release). Stratolaunch. May 31, 2017.
- Michael Mecham and Frank Morring, Jr. (Dec 19, 2011). "Allen Places Big Bet On Air Launches". Aviation Week & Space Technology.
- Jeff Foust (May 31, 2017). "Stratolaunch rolls out giant aircraft". SpaceNews.
- Doug Messier (May 5, 2012). "Space Goose's Nest Grows in the Mojave". Parabolic Arc.
- Chris Bergin (May 24, 2013). "Stratolaunch and Orbital – The Height of Air Launch". NASASpaceFlight.com.
- ATK (Aug 12, 2013). "ATK Gets Contract for Stratolaunch Propulsion System" (Press release).
- Amy Butler (Nov 6, 2014). "Stratolaunch Drops Liquid Stage From Rocket System". Aviation Week Network.
- Jason Silverstein (26 February 2015). "SEE IT: World's largest plane under construction in Calif". NY Daily News.
- Gates, Dominic (June 19, 2016). "Paul Allen's giant plane takes shape in the desert, but its market is unclear". Seattle Times.
- Christian Davenport (June 20, 2016). "Why Microsoft co-founder Paul Allen is building the world's largest airplane". Washington Post.
- Stephen Clark (October 10, 2016). "Stratolaunch announces plan to fly with Pegasus rockets". Spaceflight Now.
- Simon Sharwood (1 Jun 2017). "Microsoft founder Paul Allen reveals world's biggest-ever plane". The Register.
- Jeff Foust (19 September 2017). "Engine test latest step for Stratolaunch's giant aircraft". SpaceNews.
- "Stratolaunch Completes First Low-Speed Taxi Test" (Press release). Stratolaunch. Dec 18, 2017.
- Baylor, Michael (2018-02-26). "Stratolaunch conducts high-speed taxi tests on giant carrier aircraft". NASASpaceflight.com. Retrieved 2018-02-27.
- Wall, Mike (2018-10-29). "Stratolaunch's Rocket Carrier, the Biggest Airplane Ever Built, Aces Fastest Runway Test Yet". space.com. Retrieved 2018-11-02.
- Alan Boyle (January 9, 2018). "Stratolaunch gets world's biggest airplane ready for takeoff with 136 mph taxi test". Geekwire. Retrieved January 10, 2018.
- Guy Norris (Jan 19, 2019). "Stratolaunch Terminates Rocket Engine and Launcher Programs". Aviation Week Network.
- Dominic Gates (May 31, 2017). "Paul Allen's colossal Stratolaunch plane emerges from its lair". Seattle Times.
- "Type Certificate Number E24NE data sheet" (PDF). FAA. November 23, 2015.
- "World's biggest plane to launch in 2016: Designers reveal megaplane could send astronauts into orbit using a mini shuttle". Daily Mail. 3 August 2015.
- "Projects". Scaled Composites.
- Paul G. Allen (June 20, 2016). "Tackling the Space Challenge". LinkedIn.
|Wikimedia Commons has media related to Scaled Composites model 351 Roc.|
- Orbital ATK
- Stratolaunch Systems, A Paul G. Allen Project. YouTube. Vulcan Inc. Dec 13, 2011.
- Stratolaunch Systems Press Conference. YouTube. Ian Benecken. Dec 13, 2011.
- W.J. Hennigan (14 December 2011). "Paul Allen to build behemoth plane for space launches". The Los Angeles Times.
- Guy Norris (Feb 25, 2015). "Inside The Roc's Lair". Aviation Week.