The success of that mission will profoundly
affect American access to space. For one thing, it will mean that the
U.S. can once again use one of its own spacecraft to transport goods to
and from the space station. After the Space Shuttle was retired,
Russia's Progress spacecraft, along with Europe's Automated Transfer
Vehicle (ATV) and Japan's H-II Transfer Vehicle (HTV), have been
carrying fuel, food and other supplies needed on the space station.
But
once their task was completed, those craft were simply filled with
rubbish from the space station and allowed to burn up in the atmosphere
during re-entry. Dragon, on the other hand, will be able to bring cargo
safely back to the earth as well. In the forthcoming mission, for
instance, it will return over 600 kg of goods, including some used
hardware and samples from a materials processing experiment.
For
the U.S. space agency, the National Aeronautics and Space
Administration (NASA), a successful Dragon mission will vindicate its
efforts to let private companies take on the task of transporting humans
and cargo to orbits around Earth.
Dragon and the
Falcon 9 rocket that will launch it have both been designed to meet NASA
safety requirements for taking astronauts as well. A common design for
the capsule's cargo and manned configurations meant that critical safety
features could be tested in the course of unmanned missions, the
company pointed out. Currently, crews are wholly dependent on Russia's
Soyuz capsule and rocket to reach the orbiting outpost.
But SpaceX's vision goes beyond providing transportation services for the International Space Station.
“The
cost and reliability of access to space have barely changed since the
Apollo era over three decades ago,” observed Mr. Musk, who is the
company's CEO and also its chief designer, when he addressed a
Presidential commission in 2004. SpaceX believes that its rockets will
provide “breakthrough advances in reliability, cost, and time to
launch.”
To meet those goals, the company has configured its
rockets around a single engine that can then be turned out in large
numbers. Such high-volume engine production allowed better process
control, resulting in much higher quality, it said.
To
this end, it developed the Merlin engine that runs on liquid oxygen and
kerosene. It also took a design concept from the Soviet space programme
– the use of large numbers of a less powerful engine that can be
developed more easily. Falcon 9's first stage uses a cluster of nine
Merlin engines. Even if one of those engines failed during flight, the
company claims that the rocket will be able to successfully complete its
mission.
When Falcon 9 lifts off, those engines
together produce more thrust than four Boeing 747s. But even so they do
not match the power of just one of Saturn V's F-1 engines, five of which
fired in unison to take men to the Moon. In addition, Falcon 9's second
stage uses a single Merlin engine. In April last year, SpaceX unveiled
its Falcon Heavy configuration. This rocket will have “more payload
capability that any [launch] vehicle in history apart from the Saturn
V,” said Mr. Musk at a press conference. The rocket could see its first
flight next year.
Falcon Heavy will cluster three of
its predecessor's first stages. A total of 27 upgraded Merlin engines
will therefore fire at lift-off. As the rocket climbs, propellants from
boosters on either side will be fed to the core, keeping the latter's
tanks filled. Once empty, the boosters separate and fall back to earth
while the engines of the core stage continue to operate.
Mr.
Musk believes that the company could launch about 10 each of Falcon 9
and Falcon Heavy annually in the coming years. With Falcon Heavy, a
return to the Moon, a Mars sample return mission or a visit to an
asteroid would become possible, Mr. Musk remarked.
No comments:
Post a Comment