Wednesday, December 16, 2009

Solar Storms and Radiation Exposure on Commercial Flights

Solar storms unleash bursts of radiation that can reach crew and passengers on commercial flights at certain altitudes and latitudes.
Scientists at NASA’s Langley Research Center have completed a first attempt to accurately calculate the level of damaging radiation flight crews and passengers are exposed to on commercial airline flights. The work is an early step toward developing a model to observe radiation exposure for all commercial flights, particularly for pilots and crews who spend their careers airborne and who are at greater risk of developing certain cancers.

The study considered not only everyday radiation emanating from space, but also the additional energy unleashed during a solar storm, which can be profound. NASA scientists say not including geomagnetic effects on solar radiation in modeling radiation exposure could underestimate the dosage by 30 to 300 percent.

Researchers looked at passengers and crew on typical flights from Chicago to Beijing, Chicago to Stockholm and London to New York, during what is known as the Halloween 2003 Storm. These flights were chosen because of their long flight paths near the North Pole, where the Earth’s natural protection from radiation is weakest. Earth’s magnetic field approaches zero above the poles. The Halloween 2003 event was chosen because it was both a large and a complex storm, making it a good test for the model.

The study found that aircrew and passengers during the Chicago to Beijing flight, for example, would have been exposed to about 12 percent of the annual radiation limit recommended by the International Committee on Radiological Protection. But these exposures were greater than on typical flights at lower latitudes, and confirmed the concerns about commercial flights at high latitudes.

“The upshot is that these international flights were right there at that boundary where many of these events can take place, where radiation exposure can be much higher,” said Chris Mertens, senior research scientist at NASA’s Langley Research Center, who is leading the research effort. Mertens will present his latest results at the American Geophysical Union fall meeting in San Francisco on Dec. 16.

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