Shields are up, Captain Kirk, and we're on our way to Mars.

British and Portuguese researchers may have solved one of the biggest problems facing interplanetary travel — how to get astronauts there and back without deadly solar radiation frying their DNA and setting off a cascade of cancers and related diseases.

The answer? A force field to ward off solar particles, generated by a powerful electromagnet onboard a spaceship.

"The idea is really like in 'Star Trek', when Scotty turns on a shield to protect the starship Enterprise from proton beams," researcher Bob Bingham of the Rutherford Appleton Laboratory near Oxford, England, told Agence France-Presse. "It's almost identical, really."

A recent NASA study had concluded that manned missions to Mars would be impossible, because the lead shielding to protect astronauts during the 18-month return trip would be too heavy to get into orbit.

And in December 2006, a solar flare and the stream of charged particles that followed it caused the crews of the International Space Station and space shuttle Discovery to take cover behind heavy equipment — even though, being in low Earth orbit, the ISS is reasonably well protected by the Earth's magnetic field.

The idea of generating a force field is several decades old, but all previous versions of it had presumed a huge field hundreds of miles across — and the size of the electromagnet needed would make that impossible.

Bingham and his colleagues, who bombarded a small generated field with radiation guns, showed the "bubble" could be a lot smaller, just a few hundred yards in diameter.

The device still wouldn't shield the crew from rare, but extremely powerful, interstellar cosmic rays, but Bingham said a dense protective coating applied to a spaceship's hull would take care of that.

• Click here to read more on this from Agence France-Presse.

• Click here for the press release on the Web site of Britain's Science and Technology Facilities Council.

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