Commercial Aircraft
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Thanks to space weather, airline pilots absorb approximately as much radiation over the course of a year as a nuclear power plant employee, NASA officials revealed on Friday.

In fact, according to the US space agency, pilots are classified as "occupational radiation workers" by the Federal Aviation Administration (FAA) because they fly at heights where there is little atmosphere to protect them from cosmic rays and solar radiation.

For example, NASA officials said that during a typical polar flight from Chicago to Beijing, pilots are exposed to roughly as much radiation as if they had received a pair of chest x-rays. Over the course of their career, this can increase their risk of developing cataracts or even cancer - and passengers could also be similarly affected.

"A 100,000 mile frequent flyer gets about 20 chest x-rays," no matter what the latitude of those flights are, explained Chris Mertens, a senior research scientist at NASA's Langley Research Center. Of course, even non-flyers absorb some radiation from space weather, as cosmic rays and their by-products can reach Earth's surface and expose people at sea level to levels equal to receiving one chest x-ray approximately every 10 days.

Flying on an airplane can increase the amount of radiation exposure 10-fold or more, NASA said. The exact amount of exposure depends on multiple factors, including the altitude of the plane, the latitude of the flight plan (polar routes expose passengers to more radiation), to solar activity and sunspot count, they added.

"To help airline companies safeguard passengers and personnel, NASA is developing an experimental tool to predict exposures in real time," the space agency said. The project, which is being headed up by Mertens, has been dubbed NAIRAS or "Nowcast of Atmosphere Ionizing Radiation for Aviation Safety."

According to Mertens, the number of flights that travel over the poles has increased drastically in recent years. Using polar routes during international flights are shorter and there are fewer head winds to deal with, he explained. As a result, these flights can save airlines up to $40,000 per flight in fuel costs.

However, as NASA officials point out, "Earth's poles are where the radiation problem can be most severe. Our planet's magnetic field funnels cosmic rays and solar energetic particles over the very same latitudes where airlines want to fly. On a typical day when the sun is quiet, dose rates for international flights over the poles are 3 to 5 times higher than domestic flights closer to the equator."

"If a flight controller wants to know the situation around the poles right now, NAIRAS can help," they added. "It is, essentially, an online global map of radiation dose rates for different flight paths and altitudes. Maps are produced in near real-time by a computer at Langley, which combines cutting-edge physics codes with realtime measurements of solar activity and cosmic rays."

Currently, the project is in an experimental phase, Mertens said, but the goal is for NAIRAS to provide information comparable to land-based weather forecasts. In addition to the cost savings to airlines, the research team is hoping to help pilots better understand the radiation-related on-the-job hazards that they face.

A paper in which Mertens and this colleagues compare NAIRAS predictions with actual radiation measurements collected onboard airplanes will be published in the near future in the journal Space Weather. Mertens said that his team's results "are encouraging, but we still have work to do."