Is there enough of the rare earth element Neodymium to supply the massive amount of permanent magnets SkyTran will need?
Neodymium-iron-boron magnets Nd2Fe14B, the most powerful permanent magnet material created to date, can support 50x their weight on a passive maglev track. So a 750-lb 2-person vehicle will need at least 15 pounds of these magnets. A technology-agnostic investor could do worse than to invest in neodymium futures/mines, at least in the medium term — hybrid cars and windmills need them too. How much is that much neodymium likely to cost? The neodymium-iron-boron material Nd2Fe14B is just about 1/4 neodymium by weight (atomic weights are 144 for Nd, 56 for Fe and 10 for B; so ignoring the featherweight boron, the 7:1 ratio gives 144 / ( 144 + ( 7 * 56 ) ) = .26. So 14 pounds of magnet require just 3.9 pounds (1.8 kg) of Nd. At the peak of the 2007 supply crunch, neodymium oxide Nd2O3 (85% Nd by weight according to a similar calculation: 144 * 2 / ( 144 * 2 + 16 * 3 ) = .85) cost $60/kilo according to this May 2009 article . So we’re unlikely to ever spend more than $60 * 1.8 / .85 = $127
