Illustration of a coronal mass ejection emanating from the Sun. These events, CMEs for short, are powerful releases of solar charged particles (plasma) and magnetic field, travelling on the solar wind. When a CME hits Earth, it can cause a geomagnetic storm which disrupts the planet’s magnetosphere, our radio transmissions and electrical power lines. They can damage artificial satellites and cause long-lasting power outages. Humans in orbit are also very vulnerable to these events, whose high-energy particles are not shield by typical spacecraft.