SpaceShipTwo

The SpaceShipTwo project was based in part on technology developed for the first-generation SpaceShipOne, which was part of the Scaled Composites Tier One program, funded by Paul Allen. The Spaceship Company licensed this technology from Mojave Aerospace Ventures, a joint venture of Paul Allen and Burt Rutan, the designer of the predecessor technology.

SpaceShipTwo was a low-aspect-ratio passenger spaceplane. Its capacity was planned to be eight people — six passengers and two pilots. The SpaceShipTwo spaceplanes never flew with more than 6 people onboard (4 passengers, 2 pilots). The apogee of the new craft was designed to be approximately {{cvt|110|km}} in the lower thermosphere, {{cvt|10|km}} higher than the Kármán line but as of July 2021, the maximum height reached was 89.9 km.{{cite web |url=https://www.bbc.co.uk/news/science-environment-47336617 |title=Virgin's Unity plane rockets skyward |date=22 February 2019 |publisher=BBC}} In the end, the SpaceShipTwos never broke the 100 km limit. The predecessor craft SpaceShipOne's target was also 100 km but the last flight reached an altitude of {{cvt|112|km}}.{{Cite web |url=http://www.scaled.com/projects/tierone/combined_white_knight_spaceshipone_flight_tests |title=SpaceShipOne Flight Tests |work=Scaled Composites |url-status=dead |archive-url=https://web.archive.org/web/20100822194232/http://www.scaled.com/projects/tierone/combined_white_knight_spaceshipone_flight_tests |archive-date=2010-08-22 }} SpaceShipTwo was designed to reach {{cvt|4200|km/h}}, using a single hybrid rocket engine — the RocketMotorTwo.{{cite web |url=http://www.scaled.com/projects/rocket_motor_2_hot-fire_test_summaries|title=Project Test Summaries|access-date=5 April 2012|publisher=Scaled Composite|archive-url=https://web.archive.org/web/20140222202346/http://www.scaled.com/projects/rocket_motor_2_hot-fire_test_summaries|archive-date=22 February 2014|url-status=dead}} It launched from its mothership, White Knight Two, at an altitude of {{cvt|13500|m}},{{Cite web|url=https://www.youtube.com/watch?v=yhY9bJfi4xY|title=Replay! Virgin Galactic's 2nd commercial crew spaceflight with VSS Unity - Full Broadcast|date=10 August 2023 |via=www.youtube.com}} and reached supersonic speed within 8 seconds. After 70 seconds, the rocket engine cut out and the spacecraft coasted to its peak altitude. SpaceShipTwo's crew cabin was {{cvt|3.7|m}} long and {{cvt|2.3|m}} in diameter.{{cite web |url=http://www.flightglobal.com/articles/2008/01/23/221031/pictures-virgin-galactic-unveils-dyna-soar-style-spaceshiptwo-design-and-twin-fuselage-white-knight.html|title=Pictures: Virgin Galactic unveils Dyna-Soar style SpaceShipTwo design and twin-fuselage White Knight II configuration|access-date=23 January 2008|author=Rob Coppinger|publisher=Flightglobal}} The wing span was {{cvt|8.2|m}}, the length was {{cvt|18|m}} and the tail height was {{cvt|4.6|m}}.{{cite web|url=http://www.virgingalactic.com/pressftp/index_full.php|title=Spaceship Unveil Presspack|access-date=10 February 2008|publisher=Virgin Galactic|url-status=dead|archive-url=https://web.archive.org/web/20080216043101/http://www.virgingalactic.com/pressftp/index_full.php|archive-date=16 February 2008}}

SpaceShipTwo used a feathered reentry system, feasible due to the low speed of reentry. In contrast, orbital spacecraft re-enter at orbital speeds, close to {{cvt|25000|km/h}}, using heat shields. SpaceShipTwo was furthermore designed to re-enter the atmosphere at any angle.{{cite web|url=http://blogs.zdnet.com/BTL/?p=7678|title=Virgin Galactic unveils SpaceShipTwo; Plans open architecture spaceship|date=23 January 2008|access-date=10 February 2008|author=Dignan, Larry|publisher=ZDnet.com|archive-date=6 December 2013|archive-url=https://web.archive.org/web/20131206023230/http://www.zdnet.com/blog/btl/virgin-galactic-unveils-spaceshiptwo-plans-open-architecture-spaceship/7678|url-status=dead}} It decelerated through the atmosphere, switching to a gliding position at an altitude of {{cvt|24|km}}, and took 25 minutes to glide back to the spaceport.

SpaceShipTwo and White Knight Two were, respectively, roughly twice the size of the first-generation SpaceShipOne and mothership White Knight, which won the Ansari X Prize in 2004. SpaceShipTwo had {{cvt|43|and|33|cm}}-diameter windows for the passengers' viewing pleasure, and all seats reclined back during landing to decrease the discomfort of G-forces.{{cite web|url=http://www.space.com/news/060828_spaceshiptwo_next.html|title=Virgin Galactic Unveils SpaceShipTwo Interior Concept|access-date=6 April 2007|date=28 September 2006|author=Tariq Malik|publisher=SpaceNews}} In 2008, Burt Rutan remarked on the safety of the vehicle:

{{blockquote|This vehicle is designed to go into the atmosphere in the worst case straight in or upside down and it'll correct. This is designed to be at least as safe as the early airliners in the 1920s ... Don't believe anyone that tells you that the safety will be the same as a modern airliner, which has been around for 70 years.}}

In September 2011, the safety of SpaceShipTwo's feathered reentry system was tested when the crew briefly lost control of the craft during a gliding test flight. Control was reestablished after the spaceplane entered its feathered configuration, and it landed safely after a 7-minute flight.[http://www.space.com/13297-virgin-galactic-spaceshiptwo-test-flight-glitch.html "Virgin Galactic's private spaceship makes safe landing after tense test flight"] SPACE.com 17 October 2011 Retrieved 18 October 2011

SpaceShipTwo (and the WhiteKnightTwo launcher aircraft) were built by The Spaceship Company, originally formed as a joint venture between Scaled Composites and Virgin Galactic.{{cite news|last=Norris|first=Guy|title=Scaled And Virgin Lift Veil on Spaceship Production Progress|url=http://aviationweek.com/awin/scaled-and-virgin-lift-veil-spaceship-production-progress|access-date=8 July 2011 |publisher=Aviation Week & Space Technology|date=11 July 2011}} Virgin Galactic bought out Scaled Composites' interest in TSC in 2012, and TSC became a wholly owned subsidiary of Virgin Galactic.{{cite web|title=Virgin Galactic Acquires Full Ownership of The Spaceship Company|url=http://www.businesswire.com/news/home/20121005005907/en/Virgin-Galactic-Acquires-Full-Ownership-Spaceship-Company#.VFvXsPnF98E|publisher=Business Wire|date=5 October 2012|access-date=6 October 2012}}

The launch customer of SpaceShipTwo was Virgin Galactic, who {{as of|2005|lc=y}} had publicly announced they had ordered five vehicles,{{cite news |url=http://www.space.com/news/050727_branson_rutan.html |title=Richard Branson and Burt Rutan Form Spacecraft Building Company |publisher=SPACE.com |date=27 July 2005 |access-date=17 October 2009 }}{{cite web|url=http://www.space.com/news/080123-virgingalactic-ss2-design.html|title=Virgin Galactic Unveils Suborbital Spaceliner Design|access-date=25 January 2008|date=23 January 2008|publisher=SPACE.com|first=Tariq|last=Malik}} but only three had been ordered by 2015. The first SS2 was named VSS Enterprise.{{cite web|url=http://www.space.com/missionlaunches/virgin_space_040927.html|title=Virgin Galactic to Offer Public Space Flights|access-date=20 December 2007|publisher=SPACE.com|date=27 September 2004}} The "VSS" prefix stands for "Virgin Space Ship". VSS Enterprise was the first to fly;{{cite web|url=http://cache.gizmodo.com/assets/resources/2006/09/Comparison_SS1-SS2.jpg |title=Scale comparison chart of Spaceshipone and Spaceshiptwo|access-date=6 April 2007|publisher=Gizmodo|url-status=dead|archive-url=https://web.archive.org/web/20070317222044/http://cache.gizmodo.com/assets/resources/2006/09/Comparison_SS1-SS2.jpg|archive-date=17 March 2007}} it was destroyed in a crash on 31 October 2014.{{cite web|last=Rogers|first=Adam|title=Space Tourism Isn't Worth Dying For|url=https://www.wired.com/2014/10/virgin-galactic-boondoggle/|date=31 October 2014|publisher=Wired (magazine)|access-date=1 November 2014}}{{cite news|title=Virgin Galactic spacecraft crash kills pilot|date=31 October 2014 |url=https://www.bbc.co.uk/news/world-us-canada-29857182|publisher=BBC News|access-date=8 November 2014}} The build of VSS Unity was about 65% complete in early November 2014, and Virgin Galactic expected it to be complete in 2015. It was unveiled in February 2016{{cite news|url=http://www.newsweek.com/virgin-galactic-ceo-sees-new-spacecraft-ready-next-year-281652 |title=Virgin Galactic CEO Sees New Spacecraft Ready Next Year|publisher=Newsweek|date=2 November 2014}} and performed its first powered flight in April 2018. The third SpaceShipTwo was expected to commence construction by the end of 2015.{{cite news|url=https://www.nbcnews.com/storyline/virgin-voyage/virgin-galactic-gears-building-third-spaceshiptwo-n302191|title=Virgin Galactic Gears Up for Building Third SpaceShipTwo|date=7 February 2015|publisher=NBC News}}{{cite web|url=http://www.virgingalactic.com/update-from-mojave-testing-testing-1-2-3/ |title=Update from Mojave: Testing Testing 1-2-3|publisher=Virgin Galactic|date=10 March 2016|access-date=15 March 2016|archive-url=https://web.archive.org/web/20160315120901/http://www.virgingalactic.com/update-from-mojave-testing-testing-1-2-3/|archive-date=15 March 2016|url-status=dead}}

Unity was retired on 8 June 2024 after its final flight took place on that date, as Virgin Galactic shifted its focus to the next generation Delta-class vehicles. At the time, the only SpaceShipTwos completed and flown were the Enterprise and the Unity.{{Cite web |last=Foust |first=Jeff |date=2024-05-08 |title=Virgin Galactic plans higher mothership flight rate with next-generation spaceplanes |url=https://spacenews.com/virgin-galactic-plans-higher-mothership-flight-rate-with-next-generation-spaceplanes/ |access-date=2024-05-09 |website=SpaceNews |language=en-US}}

SpaceShipTwo was launched from the WhiteKnightTwo launcher aircraft, which took off from the Mojave Air and Space Port in California during testing. Spaceport America (formerly Southwest Regional Spaceport), a US$212 million spaceport in New Mexico, partly funded by the state government,[http://www.elpasotimes.com/news/ci_16411102 New era draws closer: Spaceport dedicates runway on New Mexico ranch] {{webarchive|url=https://archive.today/20121210172846/http://www.elpasotimes.com/news/ci_16411102|date=10 December 2012 }} El Paso Times 23 October 2010 Retrieved 25 October 2010 "two-thirds of the US$212 million required to build the spaceport came from the state of New Mexico... The rest came from construction bonds backed by a tax approved by voters in Doña Ana and Sierra counties". became the permanent launch site for the latter part of test flight programme and for commercial launches.

Two further ships were under construction by 2016.{{cite web|title=Second Spaceship in Virgin Galactic's fleet completes major build milestone|publisher=Space Daily |date=10 January 2020 |url=http://www.spacedaily.com/reports/Second_Spaceship_in_Virgin_Galactics_fleet_completes_major_build_milestone_999.html |access-date=2020-01-11}}{{cite news|url=https://www.engadget.com/2016/02/19/virgin-galactic-unveils-the-new-spaceship-two/|title=Virgin Galactic unveils the new SpaceShip Two, named the VSS Unity |publisher=Engadget|date=19 February 2016|access-date=20 February 2016|quote=The plans for this ship are for it to be the first Virgin Galactic ship that takes paid passengers to space, and the third and fourth ships are already under construction.}} It is unclear whether these are now designated to be SpaceShip III class vehicles. As of 2024, the only SpaceShipTwo-class vehicles completed and flown are Enterprise and Unity.

File:Replica of Virgin Galactic’s SpaceShipTwo at the Intrepid Museum 2014.jpg

On 28 September 2006, Virgin Group founder Sir Richard Branson unveiled a mock-up of the SpaceShipTwo passenger cabin at the NextFest exposition at the Jacob K. Javits Convention Center in New York.{{cite news|url=http://news.bbc.co.uk/1/hi/sci/tech/5394130.stm|title=Buckled up for white knuckle ride|access-date=6 April 2007|date=30 September 2006|author=Sophie Morrison|publisher=BBC News}} The design of the vehicle was revealed to the press in January 2008, with the statement that the vehicle itself was around 60% complete. On 7 December 2009, the official unveiling and rollout of SpaceShipTwo took place. The event involved the first SpaceShipTwo being christened by then - Governor of California Arnold Schwarzenegger as the VSS Enterprise.[http://news.bbc.co.uk/1/hi/business/8400353.stm Richard Branson unveils Virgin Galactic spaceplane] BBC News 7 December 2009

On 26 July 2007, an explosion occurred during an oxidizer flow test at the Mojave Air and Space Port, where early-stage tests were being conducted on SpaceShipTwo's systems. The oxidizer test included filling the oxidizer tank with {{cvt|4500|kg}} of nitrous oxide, followed by a 15-second cold-flow injector test. Although the tests did not ignite the gas, three employees were killed and three injured by flying shrapnel.Abdollah, Tami and Silverstein, Stuart (27 June 2007) [https://www.latimes.com/archives/la-xpm-2007-jul-27-me-explode27-story.html "Test Site Explosion Kills Three"] Los Angeles Times Retrieved 27 July 2007

The hybrid rocket engine design for SpaceShipTwo was problematic and caused extensive delays to the flight test program. The original rocket engine design was based on hydroxyl-terminated polybutadiene (HTPB) fuel and nitrous oxide oxidizer, sometimes referred to as an N₂O/HTPB engine.{{cite web |title=Propulsion Systems: multiple-burn, green and low-cost |url=http://sncspace.com/pdfs/Propulsion%20Systems_FINAL_web.pdf |publisher=Sierra Nevada |access-date=8 March 2013 |archive-url=https://web.archive.org/web/20140323035056/http://www.sncspace.com/pdfs/Propulsion%20Systems_FINAL_web.pdf |archive-date=23 March 2014 |url-status=dead }}{{cite web|title=Safe Hybrid Rocket |url=http://www.virgingalactic.com/overview/safety/|year=2013|publisher=Virgin Galactic|access-date=8 March 2013|url-status=dead|archive-url=https://web.archive.org/web/20130304220709/http://www.virgingalactic.com/overview/safety|archive-date=4 March 2013}} It was developed by Scaled Composites subcontractor Sierra Nevada Corporation (SNC) from 2009 to early 2014. In May 2014, Virgin Galactic announced a change to the hybrid engine to be used in SpaceShipTwo, and took the development effort in-house to Virgin Galactic, terminating the contract with Sierra Nevada and halting all development work on the first-generation rocket engine.{{cite web |title=SNC Statement in Response to Inquiries Regarding 31 October 2014 Virgin Galactic SpaceShipTwo Incident |url=http://www.sncspace.com/press_more_info.php?id=417 |access-date=1 November 2014 |publisher=Sierra Nevada Corporation |date=31 October 2014 |archive-url=https://web.archive.org/web/20141101025107/http://www.sncspace.com/press_more_info.php?id=417 |archive-date=1 November 2014 |url-status=dead }} Virgin then modified the engine design to include a change of the hybrid rocket fuel from a HTPB to a polyamide fuel formulation. In October 2015, Virgin announced that it was considering changing back to the original HTPB fuel.{{cite web |url=http://spacenews.com/virgin-galactic-switching-back-to-rubber-fuel-for-spaceshiptwo/ |title=SpaceShipTwo Bounces Back to Rubber Fuel |first=Jeff |last=Foust |date=14 October 2015 |access-date=16 October 2015 |publisher=SpaceNews}}

Rather than the rubber-based HTPB-fuel engine—engines that had experienced serious engine stability issues on firings longer than approximately 20 seconds — the engine would instead be based on a solid fuel composed of a type of plastic called thermoplastic polyamide. The plastic fuel was projected to have better performance (by several unspecified measures) and was projected to allow SpaceShipTwo to make flights to a higher altitude.{{cite news |last=Foust |first=Jeff |title=Virgin Galactic changes fuels as it prepares for its next round of test flights |url=http://www.newspacejournal.com/2014/05/24/virgin-galactic-changes-fuels-as-it-prepares-for-its-next-round-of-test-flights/ |access-date=25 May 2014 |newspaper=NewSpace Journal |date=24 May 2014 }}{{cite news|last=Boyle|first=Alan|title=Virgin Galactic Makes a Switch in SpaceShipTwo's Rocket Motor|url=https://www.nbcnews.com/storyline/virgin-voyage/virgin-galactic-makes-switch-spaceshiptwos-rocket-motor-n113216|access-date=24 May 2014|publisher=NBC News|date=23 May 2014}}{{cite news|title=New Fuel to Boost SpaceShip Two |url=http://www.aviationweek.com/space/new-fuel-boost-spaceship-two|publisher=Aviation Week|date=24 May 2014|last=Morris|first=Guy|access-date=10 December 2015}}

{{As of|2014|05}} when the version 2 engine by Virgin Galactic was publicly announced, the engine had already completed full-duration burns of over 60 seconds in ground tests on an engine test stand. The second-generation engine design also required the modification to the SS2 airframe to fit additional tanks in the wings of SpaceShipTwo — one holding methane and the other containing helium — in order to ensure a proper burn and shut-down of the new engine.{{cite news|last1=Messier|first1=Doug|title=WhiteKnightTwo in the Air Over Mojave Today |url=http://www.parabolicarc.com/2014/06/30/whiteknighttwo-air-mojave-today/|access-date=1 November 2014|publisher=Parabolic Arc|date=30 June 2014}} Additional ground tests were performed on the new engine between May and October 2014.

Following a series of rocket engine tests, Virgin announced in October 2015 that they would be changing the rocket motor back to hydroxyl-terminated polybutadiene (HTPB), with a similar formulation as they used earlier in the development program before switching to a nylon-based fuel grain. They would use HTPB to power the SpaceShipTwo when it would resume flight following the loss of the initial SS2 test vehicle in October 2014. Full qualification tests remained to be completed at the time.[http://spacenews.com/virgin-galactic-switching-back-to-rubber-fuel-for-spaceshiptwo/ SpaceShipTwo Bounces Back to Rubber Fuel] SpaceNews, 14 October 2015, accessed 26 November 2015

{{Main|RocketMotorTwo}}

The second-generation RocketMotorTwo engine was a variant of the earlier SNC basic design, but was fueled by polyamide plastic fuel, while continuing to use the same nitrous oxide oxidizer. The second-generation engine was made in-house by Virgin Galactic rather than by SNC. By December 2012, 15 full-scale tests had been successfully conducted,[http://www.scaled.com/projects/rocketmotortwo_hot-fire_test_summaries RocketMotorTwo Hot-Fire Test Summaries] {{Webarchive|url=https://web.archive.org/web/20120426095422/http://www.scaled.com/projects/rocketmotortwo_hot-fire_test_summaries |date=26 April 2012 }} Scaled.com Updated 9 August 2012 Retrieved 16 December 2012 and additional ground tests continued into March 2013.{{cite web|url=https://www.virgin.com/richard-branson/blog/this-isnt-sci-fi|title=This isn't sci-fi|publisher=Virgin.com|date=5 March 2013|access-date=5 March 2013|url-status=dead|archive-url=https://web.archive.org/web/20130307153321/http://www.virgin.com/richard-branson/blog/this-isnt-sci-fi|archive-date=7 March 2013}} In June 2012, the Federal Aviation Administration (FAA) issued a rocket testing permit to Scaled Composites, allowing it to begin SS2 test flights powered by RocketMotorTwo;{{cite web |url=http://www.flyingmag.com/news/spaceshiptwo-gets-thumbs-rocket-powered-flights|title=SpaceShipTwo Gets Thumbs Up for Rocket-Powered Flights|publisher=Flying Magazine|date=1 June 2012}} the first such powered flight took place on 29 April 2013. The engine produced {{cvt|270|kN}} of thrust.

{{main|VSS Enterprise#Flight test program|VSS Unity#Test flight program}}

File:White Knight Two and SpaceShipTwo from directly below.jpg in October 2010. VMS Eve is shown carrying VSS Enterprise.]]

File:SS2 First Launch.jpg

In September 2012, Virgin Galactic announced that the unpowered subsonic glide flight test program was essentially complete.Rosenberg, Zach; [http://www.flightglobal.com/news/articles/virgin-galactic-finishes-unpowered-flight-test-376475/ "Virgin Galactic finishes unpowered flight test"] FlightGlobal 13 September 2012 Retrieved 26 September 2012 In October 2012, Scaled Composites installed key components of the rocket engine, and SpaceShipTwo performed its first glide flight with the engine installed in December 2012.{{cite web|url=http://www.aviationweek.com/Article.aspx?id=/article-xml/asd_10_22_2012_p04-01-509022.xml|title=SpaceShipTwo Fitted With Rocket Propulsion System|publisher=Aviation Week|date=22 October 2012|access-date=14 November 2012|archive-date=12 October 2013|archive-url=https://web.archive.org/web/20131012173343/http://www.aviationweek.com/Article.aspx?id=/article-xml/asd_10_22_2012_p04-01-509022.xml|url-status=dead}}

The spacecraft's first powered test flight took place on 29 April 2013. SpaceshipTwo reached supersonic speeds in this first powered flight.{{cite web|title=SpaceShipTwo Test Summaries |url=http://www.scaled.com/projects/test_logs/35/model_339_spaceshiptwo|publisher=Scaled Composites|access-date=14 August 2013|date=8 August 2013|archive-url=https://web.archive.org/web/20130816140953/http://www.scaled.com/projects/test_logs/35/model_339_spaceshiptwo|archive-date=16 August 2013|url-status=dead}}{{cite web|title=Virgin Galactic Breaks Speed of Sound in First Rocket-Powered Flight of SpaceShipTwo|url=http://www.virgingalactic.com/news/item/virgin-galactic-breaks-speed-of-sound-in-first-rocket-powered-flight-of-spaceshiptwo/ |publisher=Virgin Galactic|access-date=29 April 2013|date=29 April 2013|url-status=dead|archive-url=https://web.archive.org/web/20130430085117/http://www.virgingalactic.com/news/item/virgin-galactic-breaks-speed-of-sound-in-first-rocket-powered-flight-of-spaceshiptwo/|archive-date=30 April 2013}} On 5 September 2013, the second powered flight was made by SpaceShipTwo.{{cite web|title=Virgin Galactic's SpaceShipTwo Succeeds in Second Rocket-Powered Flight|url=https://www.forbes.com/sites/alexknapp/2013/09/05/virgin-galactics-spaceshiptwo-succeeds-in-second-rocket-powered-flight/|work=Forbes|access-date=6 September 2013}} The first powered test flight of 2014 — and third overall — occurred 10 January 2014. The spacecraft reached an altitude of {{cvt|22000|m}} and a speed of {{cvt|1.4|Mach}}. The WhiteKnightTwo carrier aircraft released SpaceShipTwo (VSS Enterprise) at an altitude of {{cvt|14000|m}}.{{cite web|url=http://www.universetoday.com/107979/spaceshiptwo-goes-supersonic-in-third-test-flight/|title=SpaceShipTwo Goes Supersonic in Third Rocket-Powered Test Flight|author=Nancy Atkinson|publisher=Universe Today|date=10 January 2014}}

{{main|VSS Enterprise crash}}

File:NTSB Go-Team inspects a tail section of VSS Enterprise.jpg Go-Team inspects a tail section of VSS Enterprise.]]

On 31 October 2014, SpaceShipTwo VSS Enterprise suffered an in-flight breakup during a powered flight test,{{cite web|url=http://www.bakersfieldcalifornian.com/local/x1143260271/SpaceShipTwo-experiences-in-flight-anomaly|title=SpaceShipTwo disaster: Industry mourns pilot but vows to keep ...|newspaper=The Bakersfield Californian|url-status=dead|archive-url=https://web.archive.org/web/20151023044651/http://www.bakersfieldcalifornian.com/local/x1143260271/SpaceShipTwo-experiences-in-flight-anomaly|archive-date=23 October 2015}}{{Cite web|url=https://www.nbcnews.com/storyline/virgin-voyage/spaceshiptwo-feather-tail-system-deployed-prematurely-ntsb-n239721|title=SpaceShipTwo 'Feather' Tail System Deployed Prematurely: NTSB|date=3 November 2014|website=NBC News}} resulting in a crash killing one pilot, Michael Alsbury, and injuring the other. It was coincidentally the first flight to use the new type of fuel, based on nylon plastic grains.{{cite web|last1=Marks|first1=Paul|title=Virgin Galactic's Spaceshiptwo in fatal crash|url=https://www.newscientist.com/article/dn26489-virgin-galactics-spaceshiptwo-in-fatal-crash.html#.VFRiwucbOsU|website=newscientist.com|publisher=New Scientist|access-date=1 November 2014}}{{cite news

|url=https://gizmodo.com/virgin-galactic-experiences-first-major-accident-possi-1653360863|title=Virgin Galactic's SpaceShipTwo Has Crashed, Possible Casualties|publisher=Gizmodo|date=31 October 2014|access-date=31 October 2014}} The crash was caused by a premature deployment of the feathering mechanism, which was normally used to aid in a safe descent. SpaceShipTwo was still in powered ascent when the feathering mechanism deployed. Disintegration was observed two seconds later.

{{As of|October 2014}}, SpaceShipTwo had conducted 54 test flights.{{cite news|url=http://www.space.com/27376-virgin-galactic-spaceshiptwo-test-flight.html|title=Virgin Galactic's SpaceShipTwo Aces Glide Test Flight|publisher=SPACE.com|date=8 October 2014|access-date=8 October 2014|last=Wall|first=Mike}} The spacecraft had used its "feathered" wing configuration during ten of these test flights.{{cite web|url=http://www.virgingalactic.com/news/item/feather-flight-and-nitrous-vent-test-success/|archive-url=https://web.archive.org/web/20191111051050/https://www.virgingalactic.com/news/item/feather-flight-and-nitrous-vent-test-success/|url-status=dead|archive-date=11 November 2019|title=Feather flight and nitrous vent test success|publisher=Virgin Galactic|access-date=12 April 2013}}{{cite web |url=http://www.virgingalactic.com/news/item/virgin-galactic-reaches-new-heights-in-third-supersonic-test-flight/ |date=10 January 2014 |access-date=13 January 2014 |title=Virgin Galactic Reaches New Heights in Third Supersonic Test Flight |website=virgingalactic.com |url-status=dead |archive-url=https://web.archive.org/web/20140407135714/http://www.virgingalactic.com/news/item/virgin-galactic-reaches-new-heights-in-third-supersonic-test-flight |archive-date=7 April 2014 }}

The National Transportation Safety Board conducted an independent investigation into the accident. In July 2015, the NTSB released a report which cited inadequate design safeguards, poor pilot training, lack of rigorous federal oversight and a potentially anxious co-pilot as important factors in the 2014 crash.{{cite web |url=http://libraryonline.erau.edu/online-full-text/ntsb/aircraft-accident-reports/AAR15-02.pdf |title=In-Flight Breakup During Test Flight, Scaled Composites SpaceShipTwo, N339SS, Near Koehn Dry Lake, California, October 31, 2014 |work=National Transportation Safety Board |date=28 July 2015 |access-date=29 August 2017 }}{{cite web |url=https://www.ntsb.gov/news/press-releases/Pages/PR20150728.aspx |title=Lack of Consideration for Human Factors Led to In-Flight Breakup of SpaceShipTwo |publisher=NTSB |date=28 July 2015 |access-date=29 July 2015 }} {{PD-notice}} While the co-pilot was faulted for prematurely deploying the ship's feathering mechanism, the Federal Aviation Administration, Federal Aviation Administration Office of Commercial Space Transportation, and the ship's designers were also faulted for not creating a fail-safe system that could have guarded against such premature deployment.

In October 2015, it was reported that the second SpaceShipTwo would make its first flight in 2016.{{cite web|url=http://www.americaspace.com/?p=87222|title=Virgin Galactic's New SpaceshipTwo Nearing Completion as Return to Flight Tests Push to 2016|date=9 October 2015|publisher=AmericaSpace|access-date=20 February 2016}} VSS Unity was unveiled in February 2016.

A phase of testing called "Integrated Vehicle Ground Testing" began on VSS Unity in February 2016. Between 8 September and 30 November 2016, Virgin Galactic conducted a series of captive-carry flights of Unity, including planned glide flights (1 and 3 November 2016) for which the glide portion of the flight was cancelled because of wind speed.{{cite news|url=http://www.space.com/34580-virgin-galactic-attempts-spaceshiptwo-glide-test.html|title=Virgin Galactic Postpones 1st Glide Test with New SpaceShipTwo|author=Tariq Malik|date=1 November 2016|access-date=4 November 2016}}{{cite web|url=https://www.inverse.com/article/23203-virgin-galactic-scrubs-spaceshiptwo-glide-test-again|title=Virgin Galactic looks to next SpaceShipTwo glide test|website=inverse.com|date=4 November 2016|access-date=5 November 2016}}{{cite web|url=http://www.parabolicarc.com/2016/11/03/minute-scrub-spaceshiptwo-glide-flight/|title=Last Minute Scrub of SpaceShipTwo Glide Flight|publisher=Parabolic Arc|date=4 November 2016|access-date=5 November 2016|archive-date=5 April 2023|archive-url=https://web.archive.org/web/20230405143141/https://parabolicarc.com/2016/11/03/minute-scrub-spaceshiptwo-glide-flight/|url-status=dead}}{{cite web|url=http://www.spaceflightinsider.com/missions/commercial/virgin-galactic-conducts-captive-carry-flight-spaceshiptwo/|title=Virgin Galactic conducts captive carry flight of SpaceShipTwo|publisher=Spaceflight Insider|date=1 December 2016|access-date=5 December 2016|archive-date=4 April 2023|archive-url=https://web.archive.org/web/20230404192039/https://www.spaceflightinsider.com/missions/commercial/virgin-galactic-conducts-captive-carry-flight-spaceshiptwo/|url-status=dead}} Glide flights of Unity began on 3 December 2016.{{cite web|url=http://phys.org/news/2016-12-virgin-galactic-spaceship-glide-flight.html |access-date=5 December 2016|date=3 December 2016|website=phys.org|title=Virgin Galactic spaceship makes first glide flight}}{{cite web|url=https://www.telegraph.co.uk/news/2016/12/04/virgin-galactics-space-programme-moves-forward-spaceshiptwo/|date=4 December 2016|access-date=5 December 2016|title=Virgin Galactic's space programme moves forward as SpaceShipTwo carries out first successful glide test|author=David Millward|website=telegraph.co.uk}}{{cite web|url=http://www.csmonitor.com/Technology/2016/1205/Space-tourism-Virgin-Galactic-makes-successful-glide-test|title=Space tourism: Virgin Galactic makes successful glide test|date=5 December 2016|access-date=5 December 2016|author=Weston Williams|newspaper=Christian Science Monitor}}{{cite web|url=http://www.virgingalactic.com/update-from-mojave-successful-first-glide-flight-test-for-vss-unity/|title=Update from Mojave: Successful First Glide Flight Test for VSS Unity|date=3 December 2016|access-date=6 December 2016 |website=virgingalactic.com|url-status=dead|archive-url=https://web.archive.org/web/20170513225909/http://www.virgingalactic.com/update-from-mojave-successful-first-glide-flight-test-for-vss-unity/|archive-date=13 May 2017}}

After several glide flights over the preceding months, in July 2017, Richard Branson suggested that the craft was to begin powered tests at three-week intervals.{{cite web |url=https://www.bloomberg.com/news/articles/2017-07-05/branson-targets-space-by-mid-2018-as-virgin-begins-powered-tests|title=Branson Aims Mid-2018 Space Trip as Virgin Resumes Powered Tests |publisher=Bloomberg|date=5 July 2017|access-date=8 July 2017}} In September 2017, CEO George Whitesides suggested that engine testing was complete, and that only a "small number of glide flights" remained before VSS Unity would begin powered tests flights.{{cite web |url=https://www.cnbc.com/2017/09/07/virgin-galactic-ceo-company-is-returning-to-powered-flights.html |title=Virgin Galactic is returning to powered flights, CEO says, in a crucial next step for the spaceship company |publisher=CNBC |date=7 September 2017 |access-date=8 September 2017 }} In October 2017, Branson suggested that SpaceShipTwo could reach space within three months, and that he could travel to space aboard a SpaceShipTwo within six months.{{cite web |url=http://www.kob.com/new-mexico-news/virgin-galactic-founder-richard-branson-spaceflights-spaceport-america-new-mexico/4629899/ |title=Virgin Galactic founder says spaceflights could be months away |publisher=KOB |date=9 October 2017 |access-date=13 October 2017 |archive-date=14 October 2017 |archive-url=https://web.archive.org/web/20171014035145/http://www.kob.com/new-mexico-news/virgin-galactic-founder-richard-branson-spaceflights-spaceport-america-new-mexico/4629899/ |url-status=dead }}{{cite web|url=http://aviationweek.com/space/virgin-galactic-hopes-test-spaceshiptwo-space-2017|title=Virgin Galactic Hopes To Test SpaceShipTwo In Space In 2017|first=Irene|last=Klotz |publisher=aviationweek.com|date=12 October 2017|access-date=13 October 2017}} A seventh high speed glide test was completed in January 2018.{{cite web|last=January 2018|first=Mike Wall 11 |title=Virgin Galactic's VSS Unity Soars on 7th Glide Flight (Photo)|date=11 January 2018 |url=https://www.space.com/39360-virgin-galactic-spaceshiptwo-seventh-glide-flight.html|access-date=2021-03-26|publisher=SPACE.com}} On 13 December 2018, SpaceShipTwo VSS Unity reached its highest altitude up to that point, {{cvt|82.72|km}}. This surpassed the U.S. Government definition of space at {{cvt|80|km}} but not the standard used elsewhere at {{cvt|100|km}}.{{cite web |url=http://www.iop.org/resources/topic/archive/space/ |title=A brief history of space |website=iop.org |access-date=13 December 2018 }} Despite the debate on where outer space begins, Mark Stucky would receive his astronaut wings, while Frederick W. Sturckow would not as he had already flown on the Space Shuttle four times.{{cite web|url=https://edition.cnn.com/2018/12/13/tech/virgin-galactic-reaches-50-mile-space/index.html|title=Virgin Galactic reaches 50-mile space|last=Wattles|first=Jackie|date=14 December 2018|website=edition.cnn}}

Following a February 2019 spaceflight, VSS Unity began to undergo modifications in preparation for commercial service; this includes an upgrading the flight deck and installing a passenger cabin.{{cite web|url=https://spacenews.com/virgin-galactic-expects-rapid-conclusion-of-spaceshiptwo-test-flights-after-downtime/|first=Jeff|last=Foust|date=19 April 2019|access-date=19 April 2019|title=Virgin Galactic expects rapid conclusion of SpaceShipTwo test flights after downtime|website=spacenews.com}} It was later revealed in 2021 that VSS Unity had actually suffered a large crack in its structure during its 2019 spaceflight, requiring repair work to the vehicle.{{cite web|url=https://arstechnica.com/science/2021/05/will-virgin-galactic-ever-be-successful-a-new-book-provides-insights/|first=Eric |last=Berger|date=2 May 2021|access-date=2 May 2021|title=Will Virgin Galactic ever be successful? A new book offers insights|website=arstechnica.com}} Following its return to service VSS Unity made a test flight that included Richard Branson as a passenger on July 11, 2021. During this flight, the vehicle deviated from its planned flight course triggering a Federal Aviation Administration investigation into the issue. While in ascent the vehicle triggered a red warning light which indicated it had deviated from its safe flight path.{{cite web|title=The Red Warning Light on Richard Branson's Space Flight |url=https://www.newyorker.com/news/news-desk/the-red-warning-light-on-richard-bransons-space-flight |date=2021-09-01 |work=New Yorker |author=Schmidle, Nicholas }} On 2 September 2021, it was publicly announced that further SpaceShipTwo flight tests would be grounded by FAA mandate until the investigation was completed.{{cite news |url=https://www.reuters.com/business/aerospace-defense/us-bars-virgin-galactic-rocket-plane-flights-pending-mishap-probe-2021-09-02/ |title=U.S. bars Virgin Galactic rocket plane flights pending mishap probe |author=Shepardson, David |newspaper=Reuters |date=2021-09-02 }} The FAA cleared SpaceShipTwo flights to resume later in September, after deciding to expand the restricted aerospace around the vehicle's flight range.{{cite news |title=FAA clears Virgin Galactic to resume SpaceShipTwo flights |url=https://spacenews.com/faa-clears-virgin-galactic-to-resume-spaceshiptwo-flights/ |date=2021-09-29 |author=Foust, Jeff |newspaper=Spacenews }}

The final test flight (defined as final flight with only Virgin Galactic personnel onboard) was Virgin Galactic Unity 25 mission on 25 May 2023. The first operational flight of Unity (defined as the first flight flying passengers that were not Virgin Galactic employees) was Galactic 01 on 29 June 2023.

SpaceShipTwo's total development costs were estimated at around US$400 million in May 2011, a significant increase over the 2007 estimate of US$108 million.{{cite web|title=A Look at Cost Overuns and Schedule Delays in Major Space Programs|url=http://www.parabolicarc.com/2011/05/04/cost-overruns/|publisher=Parabolic Arc|date=4 May 2011|access-date=1 April 2012}}

{{stack|{{suborbital_spaceflight_timeline.svg}}}}

The duration of the flights was expected to be approximately 2.5 hours, although only a few minutes of that was to be in space. The price was initially US$200,000.{{cite web |url=http://www.zeenews.com/znnew/articles.asp?aid=339112&sid=ENV&ssid=27|title=Rich Chinese buying tickets to space|access-date=6 April 2007|publisher=Zee News}} More than 65,000 would-be space tourists applied{{when|date=July 2021}} for the first batch of 100 tickets. By December 2007, Virgin Galactic had 200 paid-up customers on its books for the early flights, and 95% were passing the 6-8 g centrifuge tests."Virgin Galactic's timetable for progress" Spaceflight Volume 50 British Interplanetary Society February 2008 p. 48 That number had increased to 575 by early 2013.

In April 2013, Virgin Galactic announced that the price for a seat would increase 25% to US$250,000 before the middle of May 2013,{{cite news |last=Messier |first=Doug |title=Reserve Your SpaceShipTwo Seat Now – Big Price Increase Coming Soon |url=http://www.parabolicarc.com/2013/04/29/reserve-your-spaceshiptwo-seat-now-big-price-increase-coming-soon/ |access-date=30 April 2013 |publisher=Parabolic Arc |date=29 April 2013 |archive-date=15 December 2018 |archive-url=https://web.archive.org/web/20181215121032/http://www.parabolicarc.com/2013/04/29/reserve-your-spaceshiptwo-seat-now-big-price-increase-coming-soon/ |url-status=dead }} and would remain at US$250,000 "until the first 1,000 people have traveled, so that it matches up with inflation since [Virgin Galactic] started".{{cite web |url=http://www.space.com/20886-virgin-galactic-spaceshiptwo-ticket-prices.html|title=Ticket Price for Private Spaceflights on Virgin Galactic's SpaceShipTwo Going Up|last=Wall|first=Mike|publisher=SPACE.com |date=30 April 2013|access-date=10 December 2015}}

The first paying customers had been expected to fly aboard the craft in 2014, following 50–100 test flights. Refining the projected schedule in late 2009, Virgin Galactic declined to announce a firm timetable for commercial flights, but did reiterate that initial flights would take place from Spaceport America. Operational roll-out would be based on a "safety-driven schedule".{{Cite AV media|people=Will Whitehorn|title=International Astronautical Congress 2009: Civilian Access to Space|medium=Video – comments at c. 20:00|publisher=Flightglobal Hyperbola |location=Daejeon, South Korea|url=http://www.flightglobal.com/blogs/hyperbola/2009/10/video-iac2009-civilian-access.html|date=27 October 2009|access-date=19 June 2013}}

In addition to making suborbital passenger launches, Virgin Galactic marketed SpaceShipTwo for suborbital space science missions.

By March 2011, Virgin Galactic had submitted SpaceShipTwo as a reusable launch vehicle for carrying research payloads in response to NASA's suborbital reusable launch vehicle (sRLV) solicitation, which was a part of the agency's Flight Opportunities Program. Virgin projected research flights might reach a peak altitude of {{cvt|110|km}}. These flights would provide approximately four minutes of microgravity for research payloads. Payload mass and microgravity levels had not been specified at the time. Since May 2021, NASA-supported technology and systems have been tested on SpaceShipTwo.{{cite web |last=Newton|first=Laura|date=2021-02-11|title=NASA-supported Tech to Fly on Virgin Galactic's SpaceShipTwo|url=http://www.nasa.gov/centers/armstrong/features/nasa-supported-tech-to-fly-on-virgin-galactic-ss2.html|publisher=NASA|access-date=2021-03-26}} {{PD-notice}}

In August 2005, the president of Virgin Galactic stated that if the suborbital service with SpaceShipTwo would be successful, the follow-up SpaceShipThree would be an orbital craft. In 2008, Virgin Galactic suggested that it may develop a high-speed passenger vehicle to offer transport through point-to-point suborbital spaceflight.{{cite web |url=http://www.flightglobal.com/Articles/2005/08/23/Navigation/200/201097/SpaceShipThree+poised+to+follow+if+SS2+succeeds.html|title=SpaceShipThree poised to follow if SS2 succeeds|access-date=6 April 2007 |date=23 August 2005|publisher=Flight International}}

{{Aircraft specs

|ref=Virgin Galactic,[http://www.virgingalactic.com/overview/spaceships/ Overview – Spaceships] {{webarchive|url=https://web.archive.org/web/20110722080445/http://www.virgingalactic.com/overview/spaceships |date=22 July 2011}} Virgin Galactic Retrieved 19 June 2013 space.com{{cite web|url=http://www.space.com/17994-how-virgin-galactic-spaceshiptwo-works.html|title=How Virgin Galactic's SpaceShipTwo Passenger Space Plane Works (Infographic)|publisher=SPACE.com|date=10 October 2012|access-date=14 November 2012}} & Popular Mechanics{{cite web |url=https://www.popularmechanics.com/space/rockets/a19694433/virgin-galactic-first-rocket-powered-supersonic-flight/|title=Virgin Galactic Conducts First Rocket-Powered Flight of VSS Unity|first=Jay |last=Bennett|date=5 April 2018|publisher=Popular Mechanics|access-date=13 December 2018}}

|prime units?=met

| crew = 2

| capacity = 6 passengers

| length m = 18.3

| span m = 8.3

| height m = 5.5

| gross weight kg = 9,740

| eng1 number = 1

| eng1 name = RocketMotorTwo

| eng1 type = liquid/solid hybrid rocket engine

| max speed kmh = 4,000

| ceiling m = 110000

}}

{{Portal|Aviation|Spaceflight|Technology}}

{{Columns-list|colwidth=30em|

• New Shepard
• Dream Chaser
• List of crewed spacecraft
• North American X-15
• Private spaceflight
• SpaceShipOne
• Space Rider
• Space Shuttle program
• SpaceShip III

}}

{{Reflist|refs=

[http://www.spaceref.com/news/viewpr.html?pid=37626 "Virgin Galactic successfully completes SpaceShipTwo glide flight test and rocket motor firing on same day"] {{Webarchive|url=https://web.archive.org/web/20200728041832/http://www.spaceref.com/news/viewpr.html?pid=37626 |date=28 July 2020 }} SpaceRef 28 June 2012

{{cite web|url=http://cosmiclog.nbcnews.com/_news/2012/12/19/16025374-spaceshiptwo-straps-on-its-engine|title=SpaceShipTwo straps on its engine|publisher=NBC News|date=20 December 2012|access-date=20 December 2012}}

{{cite web|title=SpaceShipTwo Test Summaries|url=http://www.scaled.com/projects/test_logs/35/model_339_spaceshiptwo|publisher=Scaled Composites|access-date=29 April 2013|date=29 April 2013|archive-url=https://web.archive.org/web/20130816140953/http://www.scaled.com/projects/test_logs/35/model_339_spaceshiptwo|archive-date=16 August 2013|url-status=dead}}

}}

{{Commons category|SpaceShipTwo}}

• [http://www.virgingalactic.com/ Official Virgin Galactic website]
• [http://www.scaled.com/ Official Scaled Composites website]
• [https://www.youtube.com/watch?v=u4l_TBxlgkc#t=37 Virgin Galactic], National Geographic Channel documentary, 2012
• [http://www.space.com/news/050727_branson_rutan.html Formation of The Spaceship Company] — SPACE.com (2005)
• [http://www.spacedaily.com/news/tourism-04g.html The Birth of SpaceShipTwo] — SpaceDaily (2004)
• [https://web.archive.org/web/20060920140112/http://www.cosmosmagazine.com/node/97 Space or Bust: Feature article on space tourism] — Cosmos Magazine (2005)
• [http://spacelawprobe.blogspot.com/2006/03/space-law-in-paris.html Space Law in Paris] — Space Law Probe (2006)
• [https://www.zdnet.com/pictures/images-spaceshiptwo-your-ticket-to-space/ Images of SS2 mockups] — ZDNet (2007)
• [https://www.youtube.com/watch?v=M1GiAOzKz4k "VG Powered Flight Updated Drop BRoll"] Virgin Galactic via YouTube 29 April 2013 Shows all 16 seconds of the first-flight rocket firing from three views, and most of the sequence from a fourth view

{{Virgin Galactic}}

{{The Spaceship Company}}

{{Scaled Composites}}

{{Spaceplanes}}

{{Space tourism}}

{{Reusable launch systems}}

{{Crewed spacecraft}}

Category:Virgin Galactic

Category:Scaled Composites

Category:The Spaceship Company

Category:Scaled Composites White Knight Two

Category:Crewed spacecraft

Category:Reusable launch systems

Category:Rocket-powered aircraft

Category:Experimental vehicles

Category:Spaceplanes

Category:Space tourism

Category:Suborbital spaceflight

Category:Space program fatalities

Category:Vehicles introduced in 2013

Category:American spacecraft