SPACE.com -- NASA Works on Radiation Protection Shield

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	NASA Works on Radiation Protection Shield By Associated Press posted: 11:26 am ET 01 December 2003

HUNTSVILLE, Ala. (AP) -- Researchers in Huntsville say they may have found a better shield to protect astronauts from cosmic radiation and use as the structural skin and walls of spaceships, planet outposts and space stations.

"What we are doing here with the radiation study program will affect all other long-term NASA space exploration missions," said Ed Semmes, NASA radiation study program manager at the National Space Science and Technology Center. The NSSTC and Marshall Space Flight Center are working together on the project.

"Going anywhere in the solar system or universe will depend on protecting crews from radiation," said Semmes. "Lunar exploration, which may be in the near future, and if we chose to go to Mars in the future, will be dependent on this research."

Semmes said Huntsville researchers are developing a better radiation model that would show NASA the risks of space radiation and how to combat them. He estimates researchers should have answers by 2008.

The shield, composed of several sheets of polyethylene heavily impregnated with hydrogen, is called a material composite, said Raj Kaul, an NSSTC materials scientist. The hydrogen breaks down, or diffuses, harmful radiation that could cause cancer by reducing heavy ions into lighter ones.

Exposure to lighter ions is less harmful to people than cosmic radiation, said Nasser Barghouty, also a materials scientist.

"We have the data today for space shuttle and space station," said Barghouty. "Much of what we do is an uncertain element. The question is, how do we minimize that?"

NASA and the Russian Space Agency have been sending probes to Mars for 40 years. Scientists know the radiation counts in space and on Mars' surface, but they don't know how long-term exposure would affect a space traveler, Barghouty said.

The Huntsville-developed material is strong and flexible enough to be used to build a spaceship or a space station module, Kaul said.

"We are trying to develop a material that is multifunctional," Kaul said. "If we make a spacecraft out of it, then it is not only a structural material, but it also protects the astronauts from radiation, too. This material accomplishes those goals."

Kaul said the material also acts as a shield for micrometeroids, high-speed small particles that sometimes strike a spacecraft and cause damage.

"It gives us many types of protection all in one package," Semmes said.

Initial tests prove the shield protects humans from radiation, but scientists will need more information, Semmes said. The materials will be tested extensively over the next few years in Huntsville and at Brookhaven Lab, on Long Island, N.Y.