NASA scientists studying high-altitude radiation recently published new results on the effects of cosmic radiation in our atmosphere. Their research will help improve real-time radiation monitoring for aviation industry crew and passengers working in potentially higher radiation environments.
Cosmic radiation is caused by high-energy particles that continually shower down from space. Most of these energetic particles come from outside the solar system, though the Sun is an important source during solar storms.
Earth’s magnetosphere, which acts as a giant magnetic shield, blocks most of the radiation from ever reaching the planet. Particles with sufficient energy, however, can penetrate both Earth’s magnetosphere and atmosphere, where they collide with molecules of nitrogen and oxygen. These collisions cause the high-energy particles to decay into different particles through processes known as nucleonic and electromagnetic cascades.
“The measurements, for the first time, were taken at seven different altitudes, where the physics of dosimetry is very different,” said Chris Mertens, principal investigator of the RaD-X mission at NASA’s Langley Research Center in Hampton, Virginia. “By having the measurements at these seven altitudes we’re really able to test how well our models capture the physics of cosmic radiation.”
If you could see the particles from the airplane window, you would notice them clustering in a region above the plane. The density of the atmosphere causes the decay to happen predominantly at a height of 60,000 feet, which creates a concentrated layer of radiation particles known as the Pfotzer maximum.
The RaD-X mission took high-altitude measurements, few of which previously existed, to better understand how cosmic radiation moves through Earth’s atmosphere. The results from RaD-X will be used to improve space weather models, like the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety, or NAIRAS, model, which predicts radiation events. These predictions are used by commercial pilots to know when and where radiation levels are unsafe, allowing rerouting of aircraft in the affected region when necessary.
Because of their time spent in Earth’s upper atmosphere, aircrew in the aviation industry are exposed to nearly double the radiation levels of ground-based individuals. Exposure to cosmic radiation is also a concern for crew aboard the International Space Station and future astronauts journeying to Mars, which has a radiation environment similar to Earth’s upper atmosphere. Learning how to protect humans from radiation exposure is a key step in future space exploration.
The flight mission tested two new instruments – the RaySure detector and the Teledyne TID detector – in hope that they can be installed on commercial aircraft in the future. These new instruments offer the advantage of being compact and easily produced. During RaD-X mission testing, both instruments were found to be promising candidates for future real-time, in situ monitoring.