Mertens notes that the number of flights over the poles
has skyrocketed in recent years. Airlines prefer polar
routes for international travel because they are shorter
and have reduced head winds, creating fuel savings of
tens of thousands of dollars per flight. However,
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. 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. “We
are still in an experimental phase,” he says. “The
ultimate goal of the NAIRAS effort is to adopt a
paradigm similar to terrestrial weather forecasting.”
The value to the airlines is clear. The ability to fly
over the poles can save $35,000 to $40,000 per flight in
fuel costs alone. On the other hand, altering course to
avoid a polar radiation storm can cost as much as
$100,000. A forecasting tool like NAIRAS can help the
airlines make the right decision. Of even
greater importance to Mertens is the human factor. “Back
in 2004, I went to a workshop on space weather and
aviation.
A pilot from American Airlines stood up to address the
audience: ‘Look,’ he said, ‘we are classified as
radiation workers, we are the most exposed than any
other group, yet we know the least of all the groups.’
That was a turning point for me. I wanted to do
something to help pilots better understand what they are
flying into.” And so NAIRAS was born. Mertens
and colleagues are about to publish a paper in the
journal Space Weather comparing NAIRAS predictions to
actual radiation measurements onboard airplanes.
“The results are encouraging,” he says, “but we
still have work to do.”
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