astronomy

SpaceShipTwo

SpaceShipTwo is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand SpaceShipTwo rather than just read about it. In short: The Scaled Composites Model 339 SpaceShipTwo (SS2) is a retired air-launched suborbital spaceplane type designed for space tourism. It was manufactured by The Spaceship Company, a California-based company owned by Virgin Galactic.

Key takeaways

SpaceShipTwo belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect SpaceShipTwo to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of SpaceShipTwo from memory before moving on to harder problems.

Reference excerpt

The Scaled Composites Model 339 SpaceShipTwo (SS2) is a retired air-launched suborbital spaceplane type designed for space tourism. It was manufactured by The Spaceship Company, a California-based company owned by Virgin Galactic. SpaceShipTwo was 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 glided back to Earth and performed 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 SS2 constructed successfully performed its first powered test flight. Virgin Galactic planned to operate a fleet of five SpaceShipTwo spaceplanes in a private passenger-carrying service and took bookings for some time, with a suborbital flight carrying a ticket price of US$250,000 in 2015. The spaceplane was also used to carry scientific payloads for NASA and other organizations. On 31 October 2014, during a test flight, the first SpaceShipTwo VSS Enterprise broke up in flight and crashed in the Mojave Desert. An investigation found that the craft's descent device deployed too early. Co-pilot Michael Alsbury was killed, pilot Peter Siebold was seriously injured after parachuting; he is the only person to survive a spacecraft disintegration. The second SpaceShipTwo spacecraft, VSS Unity, was unveiled on 19 February 2016. The vehicle underwent flight testing 2016–2023. Its first flight to space (above 50 miles altitude), VSS Unity VP03, took place on 13 December 2018. 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. The final flight of Unity was Galactic 07 on 8 June 2024.

Design overview 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 six people on board (four passengers, two pilots). The apogee of the new craft was designed to be approximately 110 km (68 mi) in the lower thermosphere, 10 km (6.2 mi) higher than the Kármán line but as of July 2021, the maximum height reached was 89.9 km. 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 112 km (70 mi). SpaceShipTwo was designed to reach 4,200 km/h (2,600 mph), using a single hybrid rocket engine — the RocketMotorTwo. It launched from its mothership, White Knight Two, at an altitude of 13,500 m (44,300 ft), 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 3.7 m (12 ft) long and 2.3 m (7 ft 7 in) in diameter. The wing span was 8.2 m (27 ft), the length was 18 m (59 ft) and the tail height was 4.6 m (15 ft). 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 25,000 km/h (16,000 mph), using heat shields. SpaceShipTwo was furthermore designed to re-enter the atmosphere at any angle. It decelerated through the atmosphere, switching to a gliding position at an altitude of 24 km (15 mi), 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 43 and 33 cm (17 and 13 in)-diameter windows for the passengers' viewing pleasure, and all seats reclined back during landing to decrease the discomfort of G-forces. 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.

Fleet and launch sites

Fleet history SpaceShipTwo (and the WhiteKnightTwo launcher aircraft) were built by The Spaceship Company, originally formed as a joint venture between Scaled Composites and Virgin Galactic. Virgin Galactic bought out Scaled Composites' interest in TSC in 2012, and TSC became a wholly owned subsidiary of Virgin Galactic. The launch customer of SpaceShipTwo was Virgin Galactic, who as of 2005 had publicly announced they had ordered five vehicles, but only three had been ordered by 2015. The first SS2 was named VSS Enterprise. The "VSS" prefix stands for "Virgin Space Ship". VSS Enterprise was the first to fly; it was destroyed in a crash on 31 October 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 and performed its first powered flight in April 2018. The third SpaceShipTwo was expected to commence construction by the end of 2015. 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.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with SpaceShipTwo

Start with the simplest possible case. Write down what SpaceShipTwo claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to SpaceShipTwo before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about SpaceShipTwo ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of SpaceShipTwo

In research: SpaceShipTwo appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses SpaceShipTwo in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: SpaceShipTwo is common in secondary-school and first-year university syllabi. It links to neighbouring topics American spaceplanes, Crewed spacecraft, Experimental vehicles, so understanding it makes those chapters shorter.
In everyday life: Look for SpaceShipTwo outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study SpaceShipTwo in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what SpaceShipTwo means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain SpaceShipTwo out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is SpaceShipTwo in simple terms?

Why does SpaceShipTwo matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study SpaceShipTwo?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on SpaceShipTwo.