An explosion from the sun blasted radiation into space, reaching the Earth, Mars, and the moon in 2021.
These are called coronal mass ejections, and a particularly intense one produced particles that hit Mars, Earth, and the moon in October of 2021.
If there had been an astronaut up on the moon or Mars at the time these particles hit, they would've been exposed to radiation, though the levels were below a lethal dose.
As the sun begins entering a more active stage, CMEs will likely become more common and stronger, which means more radiation risk for astronauts.
That's why his team is in near constant communication with the Space Radiation Analysis group.
Persons:
CMEs, Robert Steenburgh, Steenburgh, NASA We're, That's, they've
Organizations:
Service, European Space Agencies, NASA, National Oceanic, Atmospheric Administration, International