The RaD-X payload ascended into the stratosphere to measure cosmic radiation coming from the Sun and interstellar space. (NASA)

Imagine you’re sitting on an airplane cruising at 36,000 feet. Just above you, high-energy particles, called cosmic rays, are zooming in from outer space. While we are largely protected from this radiation on the ground, up in the thin atmosphere of the stratosphere, these particles can affect humans and electronics alike.

NASA’s RaD-X experiment, launched on a giant helium-filled balloon, has obtained some of the first measurements of their kind at altitudes from 26,000 to more than 120,000 feet above Earth. Measuring dose equivalent rate over a range of altitudes, the tests showed a steady increase in the rate higher in the atmosphere. The results will be used to improve space weather models that predict 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.