Virgin Galactic, world’s first commercial spaceline, owns and operates a human spaceflight system
consisting of two vehicles – the SpaceShipTwo spaceplane and its WhiteKnightTwo carrier aircraft:
• Uses much of the same technology, construction and design of its predecessor, SpaceShipOne (SS1),
while being twice the size in terms of wingspan and overall length and nearly six times the size in cabin
volume. SS2 has also been designed for commercial service, whereas SS1 was a proof-of-concept
• Designed to carry two pilots and up to six passengers.
• Technical specifications:
o Dimensions (rounded):
▪ Wing / tail boom span: 42 feet.
▪ Length: 60 feet.
▪ Tail height: 15 feet (with feather down).
o Cabin details: 6 passenger seats; 90-inch diameter x 12 feet long
▪ Cabin diameter approximately the same size as a business jet.
▪ Maximum possible fuselage volume is used for the passenger cabin.
▪ Large windows are positioned throughout the cabin to afford maximum viewing
potential for passengers.
▪ Reclining seat position to maximize cabin space in microgravity and for comfort during
▪ Feathering tail booms for re-entry: same concept as SS1.
o Construction: All structural components are 100 percent carbon composite.
o Propulsion: Hybrid rocket motor uses relatively benign fuel and oxidizer (the same means of
propulsion as SS1) and is controllable – can be shut down at any time during boost phase of
▪ After release from the carrier aircraft, SS2’s rocket motor is engaged for ascent to space;
glide re-entry and landing are without propulsion.
o Gear: Tricycle gear configuration; 2x wheeled main gear; 1x nose skid, with abrading shoe.
• Flight Profile:
o Total independent flight time: Approximately 30 minutes.
o Flight time including ascent to SS2 release altitude via captive carry by WhiteKnightTwo:
Between 1.5 and 2 hours.
o G-Forces: Max Gx (front-to-back; reclined position on reentry): up to +4 Gx; Max Gz (head-to-toe;
upright position on boost): +3.5 Gz.
o Zero gravity phase – Several minutes of out-of-seat time.
o Velocity: Supersonic within eight seconds of rocket ignition, with a maximum velocity of more
than Mach 3.5.
• Total Number of Flights: 70 (as of 29th May 2018 – including 5 rocket-powered, supersonic flights, as
well as numerous captive carry, glide, and cold flow test flights).
o SS2-01, called VSS Enterprise (lost during flight test in October 2014), was designed and built by
o SS2-02, called VSS Unity, was manufactured (as are subsequent vehicles) by Virgin Galactic’s
sister organization, The Spaceship Company (TSC).
WhiteKnightTwo (WK2, VMS Eve)
• Carrier aircraft for SpaceShipTwo.
• Largest carbon composite carrier craft in service (all structural components are 100 percent carbon
• Training vehicle for SS2 spaceflight:
o Can perform winding turn manoeuvres in order to simulate SS2 Gz (head to toe) profile and is
also capable of zero-G parabolas (neither yet implemented).
o Both fuselages replicate that of SS2 potentially allowing for future passenger training;
o Unique high-altitude lift aircraft potentially suitable for various payloads;
• Technical specifications:
▪ Wing span: 140 feet (approx. the same as a Boeing 737);
▪ Length: 78 feet;
▪ Tail height: 26 feet;
o Construction: Twin boom/fuselage construction;
o Powerplant: Uses four highly efficient high-bypass turbofan jet engines.
o Gear: Quadricycle gear configuration, retractable.
o Range: Approximately 2,600 nautical miles carrying SS2 (US coast-to-coast).
• Flight profile for nominal SS2 release:
o Total flight time: Approximately two hours.
o From takeoff to SS2 release: Approximately 60 minutes.
o SS2 release: Between 45,000 – 50,000 feet.
• Total Number of Flights: 249 flights (as of 29th May 2018).
o First flight: December 21st
o Test flight program complete, including high-altitude and long-duration tests.
Spaceflight System Environmental Impact
• Air launch – avoids the need for large, ground-based rocket booster systems.
• Carbon composite construction – quarter of the weight of steel for the equivalent strength – transforms
the energy requirements for both WK2 and SS2.
• Hybrid rocket motor – relatively benign, non-toxic fuels with a short burn time due to air release.
• Unpowered SS2 descent and landing.
• Vehicles are fully reusable, except for SS2’s rocket motor solid fuel housing.
• U.S. regulatory framework was originally established by the 2004 Commercial Space Launch
Amendments Act, which empowered the Office of Commercial Space Transportation within the Federal
Aviation Administration (FAA-AST) to regulate and license commercial space launch vehicles and
• That Act established the principle of Informed Consent for space flight participants, permitting a
licensed operator to carry passengers on space flights, once the passengers are informed of and accept
a comprehensive explanation of the potential risks involved.
• In November 2015, the U.S. Commercial Space Launch Competitiveness Act was signed into law. That
new law extended until 2025 the space launch risk-sharing provision mentioned above. Overall, this
new legislation modernized commercial space regulations and provided an essential legal framework
that will enable the commercial spaceflight industry to grow in the years ahead.
• In August 2016, the FAA-AST awarded Virgin Galactic a license for SpaceShipTwo operators. The license
award, which will ultimately permit commercial operations of the vehicle, was the culmination of
several years of in-depth interaction with the FAA. The license review process consists of an in-depth
review of the vehicles system design, safety analysis and flight trajectory analysis, culminating in FAAAST