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Imagine
the ideal manned spaceship. It would take off and land
horizontally, like an aircraft. It would reach orbit at about a
fiftieth of the cost per pound weight of the space shuttle. And
having returned to Earth, it could be readied for another mission
in hours rather than months.
Indeed,
if NASA had been using such a launch vehicle to service the
International Space Station instead of the space shuttle, it might
have saved American taxpayers up to 20 billion dollars.
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Far from being a science fiction dream, it may very soon become
reality; furthermore, a British reality. The Skylon spaceplane is
now being designed and tested by Reaction Engines, a wholly
private company based at Culham, Oxfordshire ( www.reactionengines.co.uk
).
Apart
from price and efficiency, it will have other advantages over the
shuttle and even the successor to the shuttle that is now being
built. Unlike the shuttle, which drops its fuel tanks into the
ocean, the Skylon will go into space and return without losing any
of its parts.
And
unlike any other manned rocket, it will have an ``abort
capability'' like an aircraft. If something goes wrong during
launch, the Skylon can still land safely. If the space shuttle
malfunctions during launch, it is doubtful whether it can abort at
all.
Skylon
will use its hydrogen fuelled, air breathing engine to take it to
a height of about 100,000 feet and a speed of 6,400 kph, or Mach
5. The oxygen in its fuel tanks will then accelerate it to 37,000
kph, or Mach 30, more than enough speed to reach orbit.
Environmentalists, some whom like to find fault with
everything, will be hard-pressed to raise any objection to it.
Being powered by hydrogen and oxygen, it cannot cause pollution.
Nor, being a single stage vehicle, will it add to the problem of
orbital debris that is caused largely by discarded rocket parts.
The
essential part of Skylon's engine, which makes it superior to
other rockets, is its ``heat exchanger'', otherwise known as its
cooling system. This is combined with its air breathing jet engine
to make one single piece of machinery. The resulting economy in
weight makes it possible for Skylon to have a retractable
undercarriage, a heat shield, and to be a single stage vehicle.
One
day, no doubt, people and cargo will be routinely lifted into
space by elevator. But there are no hard plans to build such a
system, and its construction may be a century into the future.
Until that time there will be a need for a workhorse of space, a
vehicle that introduces the public to cheap spaceflight, just as
the DC3 once made the world familiar with cheap and easy air
travel.
There
may be many people and organisations that do not want to use an
elevator into space. Since there is likely to be only one
elevator, the company that owns it will be a monopoly, and
monopolies can decide what prices to charge and who uses its
services and who doesn't. But there can be hundreds of Skylon type
launchers, with no restriction on who uses them. They and their
descendants will open up space to ordinary people.
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