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.
== Development == 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.
=== Testing === 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.
== Design == 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.
The pilot, co-pilot and flight engineer will be in the right fuselage cockpit, while the
left fuselage one is empty and unpressurized.
The flight data systems are in the left fuselage.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.Within Scaled Composites, its model number is M351.
It is nicknamed "Roc" after Sinbad's Roc, the mythical bird so big it could carry an
elephant.
== Specifications (Stratolaunch Systems Carrier) ==
Data from StratolaunchGeneral characteristics 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)
== See also == Airborne aircraft carrier
Air-launched ballistic missileRelated development
Pegasus rocket Scaled Composites White KnightAircraft of
comparable role, configuration and era
Conroy Virtus Related lists
List of large aircraft