One of the U.S. inventors of the superconducting maglev train says a bigger, better version of the technology could fire payloads from Earth into orbit.

All it would take is 1,000 miles of track running to a height of 12 miles, $20 billion and a decade to build, says James Powell, who started Startram Inc. with aerospace engineer George Maise. Triple the cost and double the construction time if you want to use it to put people in space, they say.

Powell says their system could cut the cost of getting a 2.2-pound payload to orbit to less than $40, while a passenger trip could come in at about $5,000, TG Daily reported Tuesday.

Their proposed Startram project is based on existing magnetic levitation technology and basic physics, they said.

"The infrastructure for a cargo-only version would cost on the order of $20 billion to build and could be completed within 10 years," Powell and Maise said. "A people-capable version could be built for $60 billion and be completed within 20 years."

While the principle is fairly simple, it would be an impressively ambitious project, experts said.

A 1,000-mile maglev track would have to run up at an angle to a height of about 12 miles. Superconducting magnets on the moving spacecraft would induce currents in metal loops on the acceleration tunnel walls to levitate and guide the craft.

A separate set of metal loops on the tunnel wall would carry an AC current to magnetically push on the vehicle's superconducting magnets, accelerating it to the speed of the AC current wave.

The maglev spacecraft would accelerate to a speed of about 5.6 miles per second, leaving the track like a bullet fired from a gun.