A radical electrically-powered space rocket which has the potential to cut months or years off travel times to other planets has achieved a further successful test today. The new milestone for the Variable Specific Impulse Magnetoplasma Rocket (VASIMR) was achieved with the aid of a crucial new component - a superconducting magnet made in Britain.
VASIMR is under development by the Ad Astra Rocket Company, founded by plasma physicist and former Space Shuttle astronaut Franklin Chang Díaz. According to Ad Astra:
Today’s tests build on the achievements of the VX-200i, the engine’s non-superconducting predecessor, which last fall underwent similar tests but under a greatly reduced set of requirements. A major difference between the two is the superconducting magnet, featured in the present system, which provides a ten-fold increase in the magnetic field and enables operation of the engine under conditions consistent with actual space flight.
The VX-200 superconducting magnet, the first of its kind, was delivered to Ad Astra’s Houston facility on February 10, 2009 by its manufacturer, Scientific Magnetics of Oxford, UK.
The idea of the VASIMR is to use electric power to blast plasma reaction mass out of the engine at much higher velocities than can be achieved using normal chemically-powered rockets. This means that a VASIMR spacecraft would get hugely more poke out of a given amount of fuel, enabling it to travel through space at much higher speeds. The tech can't develop enough thrust to lift itself out of Earth's gravity, but once beyond the atmosphere it would leave today's interplanetary probes - which mainly coast through space - far behind.
Chang Díaz believes that VASIMR could usefully glean its electric power from solar panels if it was operating close to the sun (Mars would be the extreme outer limit) or from onboard nuclear reactors further away. He calculates that a nuclear VASIMR craft could get to Mars in just 39 days, as opposed to the many months a chemical-rocket ship would take.
For now, Ad Astra is focused on deploying a test VASIMR unit to the International Space Station, where it would use solar power to maintain the ISS' orbit without the need for frequent, expensive resupplies of chemical rocket fuel. There's no room for the plasma drive on any of the remaining Shuttle flights, but NASA has committed to the scheme and plans on sending the kit up using a private rocket supply mission.
For its part, Scientific Magnetics in Oxford is also very chuffed with the special superconductor magnet it supplied for the VASIMR testbed. The firm describes the unit as "one of the largest and most challenging cryogen-free superconducting magnets ever built".
Scientific Magnetics also made the mighty two-tonne, three-metre helium cooled magnet for the Alpha Magnetic Spectrometer (AMS), a cosmic-ray sniffer experiment scheduled for installation aboard the ISS next year. The firm says the AMS unit "will be the first large superconducting magnet to be launched into space". ®