Deflector shields made of ionized gas are under development by British scientists. These Star Trek-style shields could be turned off or on depending on solar activity or other requirements.
Astronauts who spend time in low earth orbit are mostly protected from radiation by the magnetosphere, Earth's powerful magnetic field. However, travelers to other planets will run the risk of exposure to cancer-causing radiation from the sun and other sources outside the solar system.
According to Dr. Ruth Bamford, of the Rutherford Appleton Laboratory in Didcot, UK: "You don't need much of a magnetic field to hold off the solar wind. You could produce the shield 20-30 kilometers away from the spacecraft."
She presented the idea today at the Royal Astronomical Society National Astronomy Meeting in Preston, England. Researchers intend to create the "deflector shield" by generating a magnetic field and then filling the space around the craft with ionized gas. The magnetic field would hold the plasma in place. The same technique could be used to protect an installation on the Moon (which has no magnetosphere like the Earth's).
Once deployed, energetic particles encountering the plasma would be slowed down, sparing the occupants of the space craft or Moon installation. The Rutherford Appleton research team plans to build an artificial magnetosphere in the lab, and then eventually create a test satellite to see how the idea works in space.
As far as I know, some of the earliest thinking about how to protect the occupants of spacecraft from harmful radiation was done by early science fiction writers. John W. Campbell, wrote about a novel approach to the problem more than seventy years ago - see NASA's New Radiation Shielding First Proposed By John W. Campbell In 1936.
And speaking of Star Trek, one of the original episodes broadcast in 1967 highlighted one of the additional hazards of exposure to radiation in space – premature aging. See Radiation Aging - The Deadly Years In Space for details.
Just last year, an engineering undergrad named Daniella Della-Giustina was awarded a NASA Advanced Concepts Student Fellows Prize for suggesting that asteroids could be used as shields. This idea also has science fiction antecedents; Arthur C. Clarke proposed the same basic idea in 1960. See Undergrad Proposes Asteroids As Radiation Shields for the details on her proposal.
Read more about the space shield at the Shield to block radiation.
(This Science Fiction in the News story used with permission from Technovelgy.com - where science meets fiction.)