Using a technology pioneered by a British scientist but abandoned by the British government, NASA scientists are preparing for an electric railway to space.
They hope to accelerate a levitating spacecraft along a magnetic track from zero to 600 mph before its rockets need to fire. Since the biggest cost of launch is the fuel - each second during lift-off, space shuttle boosters burn enough fuel to power two million family cars - the technique could offer huge cuts in the price of getting into space.
The technique, known as magnetic levitation, or maglev, was first proposed by the US rocket pioneer, Robert Goddard, early in the century. But it was demonstrated by Britain's Professor Eric Laithwaite 40 years ago: a linear induction motor is used to create a magnetic field along which a vehicle could ride, swiftly, smoothly and - because it rode on the cushion of a magnetic field - without friction.
Full-scale maglev trains are now being tested in the US, Japan and Europe.
But future space travellers could soon ride a kind of bullet train to space: they could board a singlestage spacecraft at a station at the base of a mountain, ready for take off along a guideway that climbs through a tunnel carved through the mountainside. Along the track, superconducting magnets would fire in sequence, each one accelerating the spaceship faster and faster until it went soaring through the tunnel exit already at the speed of sound before it has to fire its rockets to reach its final maximum speed of five miles a second.
It now costs at least $10,000 (€9,306) to put just 1lb of payload into orbit. The race is on to find cheaper ways of getting into space and back.
In 1996, shortly before he died at 76, Prof Laithwaite was asked by NASA to demonstrate how his maglev technique could put machines into space.
The idea was tested on a 20-foot track at the University of Sussex, Brighton. NASA scientists at the Marshall space flight centre in Huntsville, Alabama, have just scaled the design up to a 50ft track 2ft wide along which they plan to accelerate a five-foot model weighing 30lb.
Magnetic levitation of the carrier and its vehicle on the track will take about 200 kilovolt amps of electricity - the equivalent of turning on 2,000 100-watt light bulbs at one time. Next year they plan to test the idea with a 400ft track. If it works, then engineers could start designing a prototype maglev rocket plane that could also "gulp" air on its way to orbit to save on liquid oxygen fuel and help cut costs even more.
The idea is to get payload launch costs down to $100 per lb, or the cost of a round trip for a human passenger down to $50,000.
Sherry Buschmann, manager of the Marshall centre's launch technologies, said: "Each launch using a full-scale maglev track would consume only about $75 worth of electricity in today's market.
"The weight of propellant is a major culprit in the high cost of conventional rocket launches. But because maglev uses an off-board energy source for launch assist the weight of the vehicle at lift-off is about 20 per cent less than a typical rocket, resulting in tremendous savings."
