Friday, May 31, 2013

Could Radiation Harm Astronauts Traveling to Mars?

Astronauts who travel to Mars one day could be exposed to dangerous levels of radiation during their trip, even if shielding techniques are used, a new study shows.

When the Mars Science Laboratory launched on Nov. 26, 2011, it began a 350-million-mile (560 million kilometers) trip to the surface of the Red Planet. During its voyage, a group of researchers, including Southwest Research Institute scientist Cary Zeitlin, monitored exactly how much radiation a piece of science hardware on the Mars rover Curiosity was exposed to over the 253-day journey from Earth to Mars.

"In space, it's between a 100 and 1,000 times higher dose rate [of radiation] than on Earth," Zeitlin noted. "It's highly uncertain what the health risk is from these exposures."

"In terms of accumulated dose, it's like getting a whole-body CT scan once every five or six days," said Dr. Cary Zeitlin, a principal scientist in SwRI's Space Science and Engineering Division and lead author of Measurements of Energetic Particle Radiation in Transit to Mars on the Mars Science Laboratory, scheduled for publication in the journal Science on May 31.

"Understanding the radiation environment inside a spacecraft carrying humans to Mars or other deep space destinations is critical for planning future crewed missions," Zeitlin said. "Based on RAD measurements, unless propulsion systems advance rapidly, a large share of mission radiation exposure will be during outbound and return travel, when the spacecraft and its inhabitants will be exposed to the radiation environment in interplanetary space, shielded only by the spacecraft itself."
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Zeitlin, whose study is detailed in the journal Science this week, collected the data with his team by turning on the Radiation Assessment Detector (RAD) instrument while Curiosity was in flight. The instrument was active from 10 days after launch until about three weeks before landing.