[FPSPACE] Enhancing magnetic sail launches using Light weight high volume magnet productio

[LARRY KLAES]

Enhancing magnetic sail launches using Light weight high volume magnet 
production

In theory, it is possible for a magnetic sail to launch directly from the 
surface of a planet near one of its magnetic poles, repelling itself from 
the planet's magnetic field. However, this requires the magnetic sail to be 
maintained in its "unstable" orientation. A launch from Earth requires 
superconductors with 80 times the current density of the best known 
high-temperature superconductors.

Other magnetic launching systems tend to use stronger magnets and shorter 
launch systems.

Earth's magnetic field is about 60 microtesla at the poles.

Compared to the skyhook, which is just barely possible with even the 
theoretical best material properties, a tower 100 km high is easy. Flawless 
diamond, with a compressive strength of 50 GPa, does not even need a taper 
at all for a 100 km tower; a 100-km column of diamond weighs 3.5 billion 
newtons per square meter, but can support 50 billion. Even commercially 
available polycrystalline synthetic diamond with advertised strengths of 5 
GPa would work. Of course in practice columns would be tapered so as not to 
waste material; and the base of the tower would be broadened to account for 
transverse forces, such as the jet stream. Only the bottom 15 km (i.e. 15%) 
of the tower lies in the troposphere and would have to be built taking 
weather into account.

Full article here:

http://advancednano.blogspot.com/2007/12/enhancing-magnetic-sail-launches-using.html