> For the elevated end portion, the design considers magnetic levitation to be relatively less expensive than alternatives for elevating a launch tube of a mass driver (tethered balloons,[19] compressive or inflated aerospace-material megastructures).[20] A 280-megaamp current in ground cables creates a magnetic field of 30 Gauss strength at 22 kilometres (14 mi) above sea level (somewhat less above local terrain depending on site choice), while cables on the elevated final portion of the tube carry 14 megaamps in the opposite direction, generating a repulsive force of 4 tons per meter; it is claimed that this would keep the 2-ton/meter structure strongly pressing up on its angled tethers, a tensile structure on grand scale.[3] In the example of niobium-titanium superconductor carrying 2 × 105 amps per cm2, the levitated platform would have 7 cables, each 23 cm2 (3.6 sq in) of conductor cross-section when including copper stabilizer.[4]
> A SPESIF 2010 presentation stated that Gen-1 could be completed by the year 2020+ if funding began in 2010, Gen-2 by 2030+.[1]
Even assuming these numbers are right, I disbelieve that we'll have the technology, let alone the resources, to magnetically levitate a megastructure 22 kilometers above the Earth, using 280 million amps of current, in the next 10 years. I don't think we even have a material strong enough to create 22km-long cables which can hold their own weight, let alone be useful as tethers.