Yet another magnetic launcher

--- In spacesettlers@y..., "Dr. Omni" wrote:
>
> Imagine a ship with a huge superconducting ring around it resting
at one of
> Earths magnetic poles. When the ship is engaged, a zillion-ampere
current
> flows through the superconducting ring and generates a magnetic
field
> opposite to the one generated by Earth. The resulting repulsion
force
> propels the ship upwards. After accelerating vertically for, let
say, 3g
> during less than six minutes, the ship would be beyond escape
velocity at
> 1.6 Mm above Earth. The vehicle would then be free from Earth's
gravity
> without spending a single drop of propellant, using just energy.
>
> Of course, two magnets repelling each other form an unstable
system, and the
> ship would likely turn upside down without a system for stabilizing
> attitude. How could that system be done? If the ship was disk shaped
> (embarrassingly similar to an UFO...), with the main magnet at the
center,
> smaller attitude magnets in the borders could actively equilibrate
the
> structure, maintaining the ship correctly aligned.
>

Thia is just the Meisner Effect writ large. And it's not a free
lunch either; the energy required to boost your superconducting ring
comes from the Earth's magnetic field, and using this system would
simply lower the earth's field slightly, possibly by slightly cooling
the core.

One thought: stability could be improved if the superconducting ring
was spinning, as it would act as a gyro.

A similar idea is proposed in David Brin's "Tank Farm Dynamo", using
tethers: http://www.orbit6.com/et/tankfarm.htm

:) ed