Right
now, without any special technology it is already good enough and no
it does not contravene the laws of physics unless you think physics
is perfectly described by Newton. Super conducting technology gives
us a true space drive that will also be able to lift of from the
Earth, throw in a fusion drive like the one they are working on at
Focus Fusion and space is ours.
It is
not anti - gravity or magnetic exclusion which are both effective
options to consider although our knowledge of gravity is still pretty
weak. Yet the potential outright thrust is huge and uses only direct
energy.
This
technology demands full financial support as soon as possible as does
Focus Fusion. The potential payoff is huge and timely. Both could
be matured to operational prototypes inside five years.
EmDrive: China's
radical new space drive
By David Hambling
06 February 13
Scientists in China
have built and tested a radical new space drive. Although the thrust
it produces may not be enough to lift your mobile phone, it looks
like it could radically change the satellite industry. Satellites are
just the start: with superconducting components, this technology
could generate the thrust to drive everything from deep space probes
to flying cars. And it all started with a British engineer whose
invention was ignored and ridiculed in his home country.
The latest research
comes from a team headed by Yang Juan, Professor of Propulsion Theory
and Engineering of Aeronautics and Astronautics at the Northwestern
Polytechnic University in Xi'an. Titled "Net thrust measurement
of propellantless microwave thruster," it was published last
year in the academic journal Acta Physica Sinica, now translated into
English.
The technology is
controversial because of that key word "propellantless".
Space drives rely on Newton's laws of motion: all are based on the
principle of firing propellant out the back at high speed, pushing
the spacecraft forward. Even with endless power from solar cells,
thrust is still limited by the supply of propellant, even with
high-velocity ion drives. Numerous attempts have been made to
overcome this, from the infamous Dean Drive of the 1950's to Nasa's
experiments with antigravity from spinning superconductors in the
1990's. All have failed, and the efforts of pseudoscientific cranks
and scammers have left the field thoroughly discredited.
British engineer Roger
Shaywer stepped into this dangerous field in 2001, after twenty years
with European satellite firm EADS Astrium. He set up his own company,
Satellite Propulsion Research (SPR) Ltd, with the aid of a modest
grant from the UK's Department of Trade and Industry.
Shawyer aimed to
develop an EmDrive: a closed, conical container which, when filled
with resonating microwaves, experiences a net thrust towards the wide
end. It seems to violate of the law of conservation of momentum,
implied by Newton, which says that no closed system can have a net
thrust. However, Shawyer says net thrust occurs because the
microwaves have a group velocity which is greater in one direction
than the other and Einstein's relativity comes into play. Group
velocity, the speed of a collection of electromagnetic waves, is a
tricky business -- a pulse of light can even have a group velocity
which is greater than the speed of light -- but can it really cause
net thrust?
Shawyer built a
demonstration thruster to test the theory in 2003. The thrust was
tiny -- 16 mN, equal to the weight of a couple of peanuts [
that is still huge and completely measurable empirical proof –
arclein ] -- but enough to validate the concept. However,
sceptics [ any semi trained fool
can attack anything and sound creditable to the ignorati in the press
who are always scouting and promoting such naysayers - arclein ] were
quick to attack. None of them actually inspected the apparatus, but
Shawyer was assailed from all sides online and in the science press.
Criticism was unsophisticated: Newton said it was impossible,
therefore he must be a fraud. Even the most advanced theoretical
critique, produced by John Costella, a PhD in relativistic
electrodynamics, amounted to arguing about the direction of an arrow
on one of Shawyer's diagrams.
Shawyer continued to
produce and test more advanced demonstrators, working out elaborate
ways of ensuring that the test results are valid and not the result
of air currents, friction, ionization, interference or
electromagnetic effects.
Such effects can
easily ruin experiments where small forces are involved. The
Nasa investigation into supposed antigravity eventually found that
the apparatus was actually causing electronic interference within the
measuring system and producing false readings rather than negating
the Earth's pull.
Boeing's Phantom
Works, which works on various classified projects and has been
involved in space research, went as far as acquiring and testing the
EmDrive, but say they are no longer working with Shawyer.
In 2007 the Russian
Research Institute of Space Systems launched an experimental
micro-satellite called Yubileiny (Jubilee) with a "non-traditional"
engine which, according to Director Valery Mesnshikov, functions
without ejecting reaction mass. However, it was later stated that
"further developments" were needed and nothing further
appears to be been published on Russian reactionless drives.
Meanwhile, the EmDrive
was picked up by Yang at Xi'an, who has a background in space
propulsion systems.
The Chinese team took
a cautious approach. They started with a new analysis in terms of
quantum theory in 2008 which indicated that the theoretical basis was
sound and net thrust is possible. The next paper in 2010 quantified
the amount of thrust that could be produced, and stated that the team
was getting positive experimental results. The latest paper describes
their latest thruster and gives the test results in details, showing
that with a couple of kilowatts of power they can produce 720 mN
(about 72 grams) of thrust.
It may not sound very
much, less than three ounces, but in space a little thrust goes a
long way. Boeing's advanced XIPS thruster, which fires out Xenon ions
at high speed, generates less than a quarter as much thrust from
twice as much power. It's used to maintain satellites in position, or
move them to a slightly different orbit. Crucially, Xips weights
about twenty kilos, more than an equivalent EmDrive, and the
propellant for prolonged operation can weigh much more.
Propellant can account
for as much as half the launch weight of a geostationary satellite.
This means that, in principle, fitting one with an EmDrive rather
than a conventional drive, could halve launch costs. Shawyer notes
that EmDrives no more powerful than the Chinese one could keep the
International Space Station in position without the need for costly
refueling.
Meanwhile, Shawyer is
moving on to bigger plans. The amount of thrust produced by an
EmDrive is determined by the Q value of the cavity, which measures
how well it resonates. A tuning fork has a high Q value in air; put
it in treacle and it is damped and does not resonate so well. By
using superconducting apparatus, Shawyer says that the Q value, and
hence thrust, can be boosted by a factor of several thousand --
producing perhaps a tonne of thrust per kilowatt of power. Suddenly
it's not about giving a satellite a slight nudge, it's about
launching spacecraft.
Shawyer estimates that
the prototype superconducting thruster could be ready in 2016. Even
the most hardened sceptic would find it hard to ignore a thruster
capable of levitating itself in the air. However, the EmDrive cannot
violate the law of conservation of energy. It can exert force, but
accelerating a vehicle over a distance still requires a huge amount
of power, and ultimately it still needs a big power supply. Personal
EmDrive jetpacks are unlikely, but Shawyer has plans for a deep space
propulsion unit, an EmDrive-assisted spaceplane capable of taking off
from an a runway and travelling to Australia in three hours -- and a
personal air vehicle the size of a car.
However, aerospace
companies are not in a hurry to do business with Shawyer, and he will
not be able to build the superconducting thruster without funding.
Yang's experimental
work is continuing; she says she is not able to discuss her work
until more results are published this year. There is also the
tantalising prospect of a demonstration at an aerospace conference.
This might make the EmDrive hard to ignore and force a showdown with
skeptics. So far the reaction in the west to Yang's work has been
muted -- perhaps polite disbelief would be the best description. 2013
may change all that.
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