"Star Trek" Shield May Protect Astronauts

Richard A. Lovett
for National Geographic News
November 4, 2008

A powerful magnetic shield may be able to deflect dangerous solar radiation from spacecraft traveling to the moon and other planets, a new study says.

Magnets tested in a recent laboratory experiment could divert radiation safely, a discovery that's "like Star Trek coming to life," said lead author Ruth Bamford, a plasma physicist at the Rutherford Appleton Laboratory in the U.K.

On Earth, humans are protected from radiation partly by the atmosphere. But our planet's magnetic field, called the magnetosphere, repels many of the harmful particles before they reach us.

"Life might not have been possible on Earth without a magnetic field as this first line of defense," Bamford said.

(Related: "Earth's Core, Magnetic Field Changing Fast, Study Says" [June 30, 2008].)

"With a journey to Mars, [radiation] is the most difficult problem," she said. "So the idea is, Why don't we just bring a magnetosphere with us?"

The idea of using magnetic fields as radiation shields was first proposed in the 1960s, but the concept languished until a resurgence of interest in manned expeditions to the moon and Mars.

Little Earthlings

One of the greatest dangers facing future astronauts is radiation, much of which comes from the sun via solar wind, a stream of particles from the sun's atmosphere.

Solar flares can be as deadly to life on Earth, and prolonged exposure to lower doses can cause cancer.

(Related: "Perfect Sun Storm Threatens Power, Phones" [October 29, 2003].)

Until recently, however, scientists thought shielding spacecraft would require an impractically large magnet—one capable of generating a field 60 miles (100 kilometers) or more across.

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