In May, a massive solar storm hit Mars, generating auroras and sending a surge of charged particles and radiation towards the planet, according to NASA. This event highlights the risks that future astronauts will face on the red planet.
The sun has been particularly active over the past year, approaching its solar maximum, an 11-year cycle that will reach its peak later this year. In recent months, intense solar flares of class X and coronal mass ejections have been recorded, releasing clouds of plasma and magnetic fields from the sun’s atmosphere.
These solar storms also reached Earth, creating colorful auroras in unusual places like northern California and Alabama. The storms originated from a group of sunspots that then rotated towards Mars.
Using orbiters and rovers, astronomers were able to closely study the impact of the solar storm on Mars. This observation is crucial for understanding the levels of radiation that astronauts might face on future missions.
Extreme Radiation on Mars
On May 20, an X12 solar flare triggered the most intense storm, sending X-rays, gamma rays, and a coronal mass ejection towards Mars. The X-rays and gamma rays reached Mars at the speed of light, followed by charged particles in a matter of minutes, according to NASA scientists.
The Curiosity rover, exploring Gale Crater, captured images during the storm, showing white streaks caused by the charged particles. The camera on the Mars Odyssey orbiter was also affected, temporarily shutting down due to the intense solar energy.
Curiosity measured the radiation with its Radiation Assessment Detector (RAD), revealing that an astronaut would have experienced a dose equivalent to 30 chest X-rays. Although not lethal, it is the highest radiation recorded since Curiosity landed almost 12 years ago.
This information is vital for planning how to protect future astronauts on Mars, considering possible shelters like cliffs or lava tubes that could provide additional shielding.
Auroras on Mars
The MAVEN orbiter observed auroras in ultraviolet light over Mars during the solar storm. Unlike Earth’s auroras, these are not concentrated at the poles due to the lack of a global magnetic field on Mars, appearing instead as a ‘global diffuse aurora.’
These events allow scientists to better understand how solar storms affect Mars. «This has been the largest solar energetic particle event MAVEN has ever seen,» said Christina Lee from the Space Sciences Laboratory at the University of California, Berkeley. With several solar events in recent weeks, scientists observed wave after wave of particles hitting Mars repeatedly.