6 November 2008

Force-field minimizes space radiation danger

by Kate Melville

A simple, portable magnetic field generator inside a spaceship should be sufficient to deflect the dangerous highly charged particles of the solar wind away from a spacecraft and the astronauts inside, according to research in Plasma Physics and Controlled Fusion.

Space weather - the term used to describe the slew of various particles and cosmic rays that saturate deep space - is the single greatest obstacle to deep space travel, exposing astronauts to deadly levels of radiation and disrupting sensitive electronics. And like the weather on Earth, space weather is hard to predict with any great accuracy. Large numbers of energetic particles can occur intermittently as "storms" with little or no warning.

The Apollo astronauts of the 1960s and 70s are the only humans to have traveled beyond the Earth's natural force field, the magnetosphere. With typical journeys on the Apollo missions lasting only about 8 days, it was sheer luck that the astronauts avoided an encounter with a storm. A journey to Mars, however, would take about eighteen months, during which time it is almost certain that the astronauts would be enveloped by a solar storm.

Now, however, scientists have shown that a smaller version of the Earth's magnetosphere can be used to protect a spaceship and its occupants. The idea has been around since the 1960s but it was thought impractical because it was believed that only a very large (more than 100km wide) magnetic bubble could possibly work.

The researchers involved, from the UK and Portugal, have used the findings from 50 years of nuclear fusion research, to show that it is possible for astronauts to shield their spacecrafts with a portable magnetosphere - scattering the highly charged, ionized particles of the solar wind and flares away from their space craft. Computer simulations done by a team last year showed that theoretically a very much smaller "magnetic bubble" of only several hundred meters across would be enough to protect a spacecraft.

Now this has been confirmed in the laboratory in the UK. By recreating in miniature a tiny piece of the solar wind, scientists working in the laboratory were able to confirm that a small "hole" in the solar wind is all that would be needed to keep the astronauts safe on their journey. "These initial experiments have shown promise and that it may be possible to shield astronauts from deadly space weather," said Dr. Ruth Bamford, one of the lead researchers from the Rutherford Appleton Laboratory.

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Source: Institute of Physics