For the first time in over 50 years, humans are leaving Earth’s protective magnetic field. The Artemis II crew of four astronauts will travel around the Moon aboard Nasa’s Orion spacecraft on a 10-day mission, venturing into a part of space where the Sun’s fury is no longer kept at bay.
Out there, solar storms are not just a technical nuisance. They can be genuinely dangerous.
WHAT IS SPACE WEATHER, AND WHY DOES IT MATTER?
Space weather refers to the ever-changing conditions driven by solar wind and eruptions from the Sun. Solar flares are the most powerful eruptions in the solar system, and the strongest ones release more energy than a billion hydrogen bombs.
Coronal mass ejections, meanwhile, are enormous clouds of solar particles, hundreds of times the size of Earth, that blast away from the Sun at tremendous speed.
The real danger for astronauts lies in what these eruptions can trigger: solar particle events. During such events, particles are accelerated to nearly the speed of light.
Too much exposure over a lifetime raises the risk of cancer and conditions that affect cognition and physical performance.
HOW IS NASA TRACKING SOLAR ERUPTIONS IN REAL TIME?
Nasa and the National Oceanic and Atmospheric Administration (Noaa) will monitor the Sun around the clock throughout the Artemis II mission.
Teams at Nasa’s Goddard Space Flight Center in Maryland will use data from multiple Sun-watching spacecraft spread across the solar system, including Nasa’s Solar Dynamics Observatory and the recently launched Interstellar Mapping and Acceleration Probe.
Even Nasa’s Perseverance rover on Mars is pitching in. Because Mars is currently on the opposite side of the Sun from Earth, the rover’s cameras can spot sunspots up to two weeks before they become visible from Earth, giving teams advance warning of regions that could produce dangerous solar flares.
HOW WILL THE CREW BE PROTECTED IF A SOLAR STORM HITS?
Inside Orion, six radiation sensors continuously measure dose rates across the cabin. Each astronaut also wears a personal radiation tracker. If radiation levels rise to a concerning level, onboard systems trigger both a visual warning and an audible alarm.
The crew is trained to act quickly. They can rearrange equipment inside the cabin, stacking it in specific areas to create additional mass between themselves and incoming particles. Since charged particles slow down as they pass through matter, adding mass is one of the most effective forms of shielding available.
The expected total radiation exposure from the mission, excluding any solar storm events, is comparable to about one month aboard the International Space Station, which is roughly five per cent of an astronaut’s career limit.
