The global site of the UK's leading magazine for automation, motion engineering and power transmission
1 March, 2024

Twitter link

Linear motor launchpad could slash takeoff costs

01 November, 1999

Linear motor launchpad could slash takeoff costs

NASA engineers are testing a scale model of an electromagnetic launchpad that could slash the cost of putting spacecraft into orbit. The engineers have built a 15m-long test track which can accelerate a 13.6kg model spacecraft to 60mph (95.5km/h) is less than 0.5s.

The electromagnetic launcher is based on the ideas of the late Professor Eric Laithwaite and is being developed in collaboration with some of his former colleagues at the University of Sussex. The launcher is essentially a linear induction motor with a fixed section that creates a magnetic field to drive an aluminium carrier along the track.

The 60cm-wide track, at Nasa`s Marshall Space Flight Centre in Alabama, consists of ten 1.5m-long sections, each weighing about 225lb and shrouded in stainless steel. The 1.5m-long model spacecraft rides on a horseshoe-shaped aluminium carrier that rises about 1cm above the track when the 200kVA supply is applied.

A full-scale version of the maglev (magnetic levitation) launcher would accelerate a spacecraft to around 965km/h (600mph) before switching to rocket engines to take it into orbit. The NASA engineers reckon that the electromagnetic assistance could cut the take-off weight of space vehicles by around 20% - resulting in considerable cost savings.

"The weight of the propellant is a major culprit in the high cost of conventional rocket launches," explains Sherry Buschmann, manager of launch technologies at the Marshall centre. "Each launch using a full-scale maglev track would consume only about $75 (£45) worth of electricity".

A 120m-long test track is planned for next year. This could be followed by a 1.5km-long track capable of launching an 18,000kg payload.

"We`ve known that linear induction motors can produce thrust," says Bill Jacobs, the lead maglev engineer at Marshall. "Now, we want to demonstrate that control can be maintained at high speeds along the maglev track."

The engineers are also looking at methods of distributing power to small sections of track at a time, to limit energy consumption.

The maglev project is part of a Nasa programme aimed at cutting the cost of putting payloads into space from today`s $10,000/lb (£13,440/kg) to a few hundred dollars per pound. In addition to its activities at Marshall, Nasa is working with a Californian team to build another linear motor track based on permanent magnets and avoiding complex feedback circuits.

  • To view a digital copy of the latest issue of Drives & Controls, click here.

    To visit the digital library of past issues, click here

    To subscribe to the magazine, click here



"Do you think that robots create or destroy jobs?"



Most Read Articles