NASA's latest findings on cosmic radiation exposure during commercial airline flights

Airline routes are planned with weather in mind, but not just the kind you see out the window. The flights you take also pass through changing conditions in space that can affect the radiation dose people receive at cruising altitude.

NASA just flew instruments over Greenland to tighten those estimates. The team measured the radiation dose on board, then compared the results to global maps used by airlines and researchers to plan safer flight paths.

Radiation changes with latitude

“The radiation exposure is maximum at the poles and minimum at the equator because of the effect of Earth’s magnetic field,” explained Chris Mertens, principal investigator of Space Weather Aviation Radiation (SWXRAD) at NASA Langley.

“In the polar regions, the magnetic field lines are directed into or out of the Earth, so there’s no deflection or shielding by the fields of the radiation environment that you see everywhere else.”

Greenland is a region where the shielding of cosmic radiation by Earth’s magnetic field is zero. Flights that pass near the poles, like some U.S. to Asia routes, face higher radiation levels compared with trips that stick closer to the equator.

The term cosmic radiation refers to high energy particles from the Sun and from outside our solar system that stream into Earth’s atmosphere.

These particles collide with air molecules and produce showers of secondary particles that can reach jet altitudes.

The broader topic is space weather, the day to day and storm level variability in the charged particles and magnetic fields moving through near Earth space.

Airlines care because a large solar storm can briefly raise dose rates at high latitudes and altitudes, and the effect is not the same everywhere.

Measuring radiation on flights

NASA’s team based a small research aircraft in Nuuk and flew two five hour sorties between August 25 and 28, carrying instruments that record dosimetry, the radiation dose accumulated during a flight.

The measurements are used to check model predictions in a part of the world where the geomagnetic field provides little shielding.

Researchers selected Greenland because it strips away a major variable.

When the magnetic shielding is near zero, any mismatch between measurements and predictions is more likely due to how the particles are modeled in the atmosphere, not to uncertain magnetic effects.

The crew flew with compact sensors called dosimeters and logged the exact route, altitude, and time. Those details make it possible to do one to one comparisons with the predicted dose along the same path.

NAIRAS model and flight radiation

The map that airlines and spaceflight planners consult is the NAIRAS model, short for the Nowcast of Aerospace Ionizing Radiation System.

This model produces hourly global maps of the radiation environment at flight altitudes. NAIRAS runs continuously and also offers a run on request mode for custom trajectories.

NAIRAS is physics based. It propagates galactic cosmic rays (GCR) and solar energetic particles (SEP) through the heliosphere, the magnetosphere, and the atmosphere, and then applies material shielding to estimate dose inside an aircraft.

The Greenland flights let the team check the model where magnetic cutoff is minimal. If there is a gap, modelers can focus on particle transport and interactions in the atmosphere rather than the field geometry.

Recent NAIRAS version 3 updates refined the treatment of particle transport at the high altitudes that influence airline cruising levels and compared outputs to NASA’s RaD X campaign data. 

Tighter validation helps move the maps from informative to actionable. Flight planners, meteorologists, and safety officers can better weigh routing options during periods of active space weather.

Risks for crews and passengers

For most travelers, the added dose from a typical flight is small. The CDC estimates that an average person receives about 0.33 millisievert of cosmic radiation each year from natural background, and a U.S. coast to coast flight adds about 0.035 millisievert.

Frequent flyers and aircrew face higher cumulative exposure because of more time at altitude. That is why regulations and company policies track dose for crew members, and why models like NAIRAS matter.

Latitude and altitude make a difference that shows up in the numbers. FAA guidance notes that galactic cosmic radiation over the polar regions is about twice that over the geomagnetic equator at the same altitude.

Routing can reduce exposure during an event. A temporary change in altitude or latitude, even by a few hundred miles, can lower dose rates when conditions warrant adjustment.

Helping Mars and Moon missions

NASA’s flights were aimed at aviation safety on Earth, but the same instruments and methods translate to exploration.

A validated approach to measuring and modeling radiation in one thin atmosphere is a good starting point for other worlds.

Air puts up a fight against particle showers, even when thin. Mars has a different atmosphere and no global magnetic field, so models must adapt their inputs and transport physics, then be tested against new measurements.

The team’s focus on clean comparisons is practical.

If a model can match measurements in extreme terrestrial conditions, like Greenland’s low shielding, then the next step is to fly the same payloads on high altitude balloons or planetary probes that sample new regimes.

Validation work is not flashy, but it is the bedrock of reliable predictions.

Crews on long haul flights and astronauts riding through solar energetic particles need the numbers to be trustworthy when conditions change quickly.

Radiation, flights, and human health

Students learn that invisible forces shape natural systems. Here, a magnetic field you cannot see bends charged particles and changes the dose you receive in the cabin by latitude, altitude, and solar activity.

Travelers get context for headlines about solar storms. Most of the time, dose rates are low, and flights continue normally, but airlines and agencies quietly adjust routes and altitudes when the Sun acts up.

Pilots and flight planners want the best tools they can get. Real world measurements tied to the same model they use day to day are the simplest way to build confidence without adding new risk.

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