Richard
Branson's Virgin Galactic has stunned the world recently with the unveiling of
SpaceShipTwo (SSII), the world's first commercially viable private
spacecraft. SSII is the successor to
Scaled Composite's SpaceShipOne, which won the $10 million Ansari X-Prize in
2004. SSII will provide six lucky (and
high paying) passengers with the opportunity to leave the Earth's atmosphere,
reaching an apogee of about 68 miles.
Total flight time will be about two and a half hours.
The SSII is
powered by a hybrid rocket engine, which burns both solid and liquid fuel, a
really safe design which allows the thrust to be throttled or even cut off. This engine will not be ignited until SSII is
first carried to an altitude of 50,000 feet by the launch vehicle, named WhiteKnightTwo
(WKII). WKII will have a wingspan of
about 140 feet, which compares to 124 feet for the Boeing 757. It is powered by four Pratt & Whitney
PW308A engines and has two fuselages, in between which SSII is mounted, and
which are exact replicas of the fuselage of SSII. This is an ideal way of training potential
SSII passengers before an actual flight into space. SSII has a wing structure which is able to be
feathered upon re-entry, allowing it to stably re-enter the atmosphere belly
first, improving the drag profile.
Training is an essential part of the program
as passengers will experience a range of g-forces, 0g during spaceflight, over
3g during ascent, and as much as 6g upon reentry. In addition to training for weightlessness by
flying parabolas in WKII, passengers will train for the high g-forces in
centrifuges.
As well as
physiologically healthy, potential passengers must also be financially healthy,
for tickets will initially cost an astronomical $200,000. Branson says this price will come
down in the future, but leaves no indication of when such a time may come.
As the
first privately owned and operated space vehicle, SpaceShipTwo has taken the
world of aerospace to the next level. It's
exciting to think that in just over 100 years, the field of aerospace has
started from scratch, and advanced to the point where a well-to-do, but
otherwise average civilian can fly in space.
I can only imagine where we'll be in another 100 years.
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