The Scaled Composites Model 339 SpaceShipTwo (SS2) is an air-launched suborbital spaceplane type designed for space tourism. It is manufactured by The Spaceship Company, a California-based company owned by Virgin Galactic.
SpaceShipTwo is carried to its launch altitude by a Scaled Composites White Knight Two, before being released to fly on into the upper atmosphere powered by its rocket engine. It then glides back to Earth and performs a conventional runway landing.The spaceship was officially unveiled to the public on 7 December 2009 at the Mojave Air and Space Port in California. On 29 April 2013, after nearly three years of unpowered testing, the first one constructed successfully performed its first powered test flight.
Virgin Galactic plans to operate a fleet of five SpaceShipTwo spaceplanes in a private passenger-carrying service and has been taking bookings for some time, with a suborbital flight carrying an updated ticket price of US$250,000. The spaceplane could also be used to carry scientific payloads for NASA and other organizations.
On 31 October 2014 during a test flight, VSS Enterprise, the first SpaceShipTwo craft, broke up in-flight and crashed in the Mojave desert. A preliminary investigation suggested the feathering system, the ship's descent device, deployed too early. One pilot was killed; the other was treated for a serious shoulder injury after parachuting from the stricken spacecraft.
The second SpaceShipTwo spacecraft, VSS Unity, was unveiled on 19 February 2016.
The SpaceShipTwo project is 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 licenses this technology from Mojave Aerospace Ventures, a joint venture of Paul Allen and Burt Rutan, the designer of the predecessor technology.
SpaceShipTwo is a low-aspect-ratio passenger spaceplane. Its capacity will be eight people — six passengers and two pilots. The apogee of the new craft will be approximately 110 km (68 mi) in the lower thermosphere, 10 km (6.2 mi) higher than the Kármán line which was SpaceShipOne's target, although the last flight of SpaceShipOne reached a one-time altitude of 112 km (70 mi). SpaceShipTwo will reach 4,200 km/h (2,600 mph), using a single hybrid rocket engine — the RocketMotorTwo. It launches from its mother ship, White Knight Two, at an altitude of 15,000 metres (50,000 ft), and reaches supersonic speed within 8 seconds. After 70 seconds, the rocket engine cuts out and the spacecraft will coast to its peak altitude. SpaceShipTwo's crew cabin is 3.7 m (12 ft) long and 2.3 m (7.5 ft) in diameter. The wing span is 8.2 m (27 ft), the length is 18 m (60 ft) and the tail height is 4.6 m (15 ft).
SpaceShipTwo uses a feathered reentry system, feasible due to the low speed of reentry. In contrast, the Space Shuttle and other orbital spacecraft re-enter at orbital speeds, closer to 25,000 km/h (16,000 mph), using heat shields. SpaceShipTwo is furthermore designed to re-enter the atmosphere at any angle. It will decelerate through the atmosphere, switching to a gliding position at an altitude of 24 km (15 mi), and will take 25 minutes to glide back to the spaceport.
SpaceShipTwo and White Knight Two are, respectively, roughly twice the size of the first-generation SpaceShipOne and mother ship White Knight, which won the Ansari X Prize in 2004. SpaceShipTwo has 43 and 33 cm (17 and 13 in) -diameter windows for the passengers' viewing pleasure, and all seats will recline back during landing to decrease the discomfort of G-forces. Reportedly, the craft can land safely even if a catastrophic failure occurs during flight. In 2008, Burt Rutan remarked on the safety of the vehicle:
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.
October 2014 crash
On October 31, 2014, SpaceShipTwo VSS Enterprise suffered an in-flight breakup during a powered flight test, resulting in a crash killing one pilot and injuring the other. It was coincidentally the first flight to use the new type of fuel, based on nylon plastic grains. The crash is believed to have involved a premature deployment of the feathering mechanism, which is 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.
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 without recent flight experience as important factors in the 2014 crash. While the co-pilot was faulted for prematurely deploying the ship's feathering mechanism, the ship's designers were also faulted for not creating a fail-safe system that could have guarded against such premature deployment.
After the loss of VSS Enterprise
In October 2015 it was reported that the second SpaceShipTwo will make its first flight in 2016.
SpaceShipTwo's total development costs were estimated at around $400 million in May 2011, a significant increase over the 2007 estimate of $108 million.
The duration of the flights will be approximately 2.5 hours, though only a few minutes of that will be in space. The price will initially be $200,000. More than 65,000 would-be space tourists applied 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. By the start of 2011, that number had increased to over 400 paid customers, and to 575 by early 2013. In April 2013, Virgin Galactic announced that the price for a seat would increase 25 percent to $250,000 before the middle of May 2013, and would remain at $250,000 "until the first 1,000 people have traveled, so that it matches up with inflation since [Virgin Galactic] started."
Following 50–100 test flights, the first paying customers were expected to fly aboard the craft in 2014. 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 will be based on a "safety-driven schedule". In addition to making suborbital passenger launches, Virgin Galactic will market SpaceShipTwo for suborbital space science missions.
NASA sRLV program
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 is a part of the agency's Flight Opportunities Program. Virgin projects research flights with a peak altitude of 110 km (68 mi). These flights will provide approximately four minutes of microgravity for research payloads. Payload mass and microgravity levels have not yet been specified. The NASA research flights could begin during the test flight certification program for SpaceShipTwo.
In August 2005, the president of Virgin Galactic stated that if the suborbital service with SpaceShipTwo is successful, the follow-up SpaceShipThree will be an orbital craft. In 2008, Virgin Galactic changed their plans and decided to make it a high-speed passenger vehicle, offering transport through point-to-point suborbital spaceflight.
Capacity: 6 passengers
Length: 18.3 m (60 ft)
Wingspan: 8.3 m (27 ft)
Height: 5.5 m (18 ft – rudders down)
Loaded weight: 9,740 kg (21,428 lb)
Powerplant: 1 × RocketMotorTwo liquid/solid hybrid rocket engine
Maximum speed: 4,000 km/h (2,500 mph)
Service ceiling: 110,000 m (361,000 ft)