Scientists have observed the impact of a vast solar storm that boosted radiation levels on Mars—and what they learned could help us understand the risks of colonizing the red planet.
The solar event, which took place on September 11, lit up the planet with a global aurora 25 times brighter than any previous one observed by NASA’s Mars Atmosphere and Volatile Evolution, or MAVEN, mission, the program's scientists said.
The Curiosity rover, NASA's on-surface, unmanned Mars mission, picked up levels of radiation on the surface more than double any measured since it landed in 2012. This spike lasted for more than two days.
"NASA's distributed set of science missions is in the right place to detect activity on the sun and examine the effects of such solar events at Mars as never possible before," said MAVEN program scientist Elsayed Talaat.
Scientists believe that measuring the effects of solar weather like this on Mars is an important precursor to sending any humans to the red planet—a prospect raised by researchers including the billionaire tech CEO Elon Musk. Significant levels of radiation can reach Mars' surface from bursts like this, and interacts with the atmosphere to produce secondary particles that would a risk to anyone on the surface.
"If you were outdoors on a Mars walk and learned that an event like this was imminent, you would definitely want to take shelter, just as you would if you were on a space walk outside the International Space Station," said RAD Principal Investigator Don Hassler of the Southwest Research Institute's Boulder, Colorado.
“To protect our astronauts on Mars in the future, we need to continue to provide this type of space weather monitoring there."
The event coincided with an active period for the sun during what is normally a quiet portion of its cycle. A series of powerful solar storms in recent weeks were also detected from earth, with some having a mild effect on radio and other communications.
"The current solar cycle has been an odd one, with less activity than usual during the peak, and now we have this large event as we're approaching solar minimum," said Sonal Jain of the University of Colorado Boulder's Laboratory for Atmospheric and Space Physics, who is a member of MAVEN's Imaging Ultraviolet Spectrograph instrument team.