Monday, December 17, 2018

VSS Unity - A Welcome Christmas Gift to Space Fans Everywhere

          By Brian Orlotti

On December 13th,  Las Cruces NM based Virgin Galactic’s suborbital Spaceship Two spacecraft, dubbed VSS Unity, reached the edge of space during a powered test flight, marking the first human spaceflight from US soil since the end of the US Space Shuttle program in 2011.

After years of delays and setbacks, the company has cause for celebration; for its own success as well as the likely future success of others and the end of US dependence on Russian craft for human spaceflight.


As outlined in the December 13, 2018 The Virge post, "Virgin Galactic’s spaceplane finally makes it to space for the first time," the VSS Unity climbed to an altitude of 82.7 km after launch from California’s Mojave Desert.

There is some debate as to whether Unity reached space, since the internationally recognized boundary is 100 km, aka the Kármán line. However, the US Air Force awards astronaut wings to personnel who reach an altitude of 80 km.

Aboard the craft were pilot Mark "Forger" Stucky and co-pilot Frederick "C.J." Sturckow. VSS Unity is designed to carry six passengers, two pilots and scientific experiments on brief trips to suborbital space. Virgin Galactic is selling seats on the craft for $250,000 US ($335,000 CDN) each.

In a typical flight profile, a SpaceShipTwo-type craft such as VSS Unity is launched from its mother ship, White Knight Two, at an altitude of 15,000 metres, then fires its single hybrid rocket engine to achieve supersonic speed within 8 seconds. After 70 seconds, the engine cuts out and the spacecraft coasts to its maximum altitude.

The crew cabin is 3.7 m long and 2.3 m in diameter. Its wing span is 8.2 m with a length of 18 m while its tail height is 4.6 m. 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.


VSS Unity uses a feathered wing for re-entry, made possible by its lower re-entry speed as a suborbital craft. This in contrast to orbital spacecraft, which require heat shields due to their much higher re-entry speeds.

The ship is also designed to re-enter the atmosphere at any angle. It decelerates through the atmosphere, switching to a gliding position at an altitude of 24 km, then takes 25 minutes to glide back to its spaceport.

The success of VSS Unity comes at a key time for the commercial space industry. Blue Origin is developing its own reusable suborbital spacecraft, New Sheppard, with ticket sales expected to begin next year. In the orbital spaceflight realm, two other US firms are developing and near operational deployment of spacecraft to fulfill multi-billion-dollar NASA contracts to ferry astronauts to and from the International Space Station (ISS).

SpaceX’s Crew Dragon is scheduled to launch on its first uncrewed test flight to the International Space Station (ISS) on January 17th, 2019 while Boeing’s CST-100 Starliner will do so in March. If all goes well on these flights, SpaceX will send a crewed test flight to the station in June, with Boeing following in August 2019.

The successful flight of VSS Unity is a welcome Christmas gift to space aficionados everywhere as well as a sign of greater things to come.
Brian Orlotti.
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Brian Orlotti is a network operator at the Ontario Research and Innovation Optical Network (ORION), a not-for-profit network service provider to the education and research sectors.

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