Commercial aircraft crews and passengers are not exposed to increased radiation while traveling at cruising altitude over the South Atlantic, where a magnetic anomaly is recorded.
Three researchers from the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) precisely measured the radiation levels experienced on board a non-stop flight from Hamburg to the Falkland Islands. Their first results are now available: at a cruising altitude of 43,000 feet, the Earth’s atmosphere continues to act as an effective shield against cosmic radiation below this magnetic anomaly.
The South Atlantic Anomaly (SAA) is located off the coast of Brazil. It is caused by the shift of Earth’s magnetic field axis, which does not pass directly through the Earth’s centre. As a result, the inner Van Allen radiation belt in the South Atlantic region extends down particularly close to Earth. This leads to increased radiation levels in near-Earth space – home to the International Space Station (ISS) – in the region.
“No additional radiation exposure could be detected for commercial flights travelling through the geographical region of the South Atlantic Anomaly. This has been confirmed by our preliminary analyses,” says Matthias M. Meier from the DLR Institute of Aerospace Medicine in Cologne. “At cruising altitudes up to 13 kilometres, the SAA has no impact on radiation exposure under stable space weather conditions”, said Matthias M. Meier of the DLR Institute for Aerospace Medicine in Cologne in a statement.
The DLR team was able to verify its own model calculations on board a Lufthansa Airbus A350-900 and add to findings from previous measurement flights. The passenger aircraft traversed the entire geographical region of the SAA at a constant altitude of approximately 13 kilometres. The measuring instruments had their own seats in row 15 of the aircraft. They were installed close to the centre of gravity of the Airbus to reduce the effects of turbulence as much as possible.
The results of the measurements are particularly significant due to the currently low influence of space weather generated by the Sun. At the moment, solar activity levels are very low – there are very few sunspots, for example. “Solar activity is the motor driving the solar wind, which has a significant impact on how many energetic particles from the galaxy reach Earth,” explains Meier, who leads the institute’s Radiation Protection in Aviation Group.
The Radiation Measurement In Space (RAMIS) detector on the Eu:CROPIS satellite has been collecting corresponding data from space since December 2018. Using these data, it has been possible to clearly measure the increase in galactic cosmic rays during the period of reduced solar activity. The satellite’s orbit takes it over almost the entirety of Earth’s surface. This makes it possible to determine how the galactic cosmic radiation varies according to the satellite’s position in orbit and the shielding of Earth’s magnetic field.