Artemis II and the invisible hazard on the way to the Moon

Summary

The most important data from NASA’s first crewed Artemis II mission may not be its photographs, but the radiation measurements that will shape how humans work and survive beyond travel farther from Earth’s magnetic shelter safely. Artemis II science operations will lay the foundation for safe and efficient human exploration of the Moon and Mars. The investigations will encompass human health, lunar science, CubeSats, Science Operations and Space weather. One of ANSTO's radiation dosimetry experts, Dr Mitra Safavi Naeini (pictured left) explored the approach undertaken by NASA. When NASA launched Artemis II on 1 April 2026, sending Reid Wiseman, Victor Glover, Christina Koch and Jeremy Hansen on a 10-day lunar flyby, it sent humans beyond low Earth orbit and back into the deep-space radiation environment for the first time since the Apollo program. Radiation is one of the mission’s core scientific and operational questions. Along with four astronauts went cabin monitors, crew-worn dosimeters, an upgraded German heavy-ion detector, organ chits, saliva and blood sampling, and performance studies. The flight is testing the Orion and the Space Launch System with a crew aboard, but it is also characterising the radiation field inside the spacecraft, measuring how that environment field changes with trajectory and shielding, and linking those physical measurements to biomarkers, performance data and biological experiments. The radiation environment The first thing to get right is that 'radiation level' is not a single number. Beyond Earth orbit, astronauts face three overlapping hazards: trapped particles in the Van Allen belts, solar particle events from the Sun, and galactic cosmic rays from outside the solar system. The belts are intense but brief—the spacecraft crosses them quickly. Solar particle events are intermittent and operationally urgent; they can raise dose rates sharply over hours. Galactic cosmic rays are the chronic background: a low-dose-rate field of very...