Mystery radiation ‘clouds’ may pose risk to air travellers

We have long known that high-altitude flight exposes us to cosmic rays. The radiation dose on a flight from London to Tokyo is roughly equivalent to a chest X-ray.

Now research flights have revealed the existence of “clouds” where radiation levels can be at least double the usual level. They were discovered as a result of the NASA-funded Automated Radiation Measurements for Aerospace Safety (ARMAS) programme, which aims to develop new methods of measuring and monitoring high-altitude radiation.

In 265 flights, radiation levels detected generally followed the expected pattern, but in at least six instances they surged, as though the aircraft was flying through a radiation cloud.