Space Weather Impact of the September 2017 Solar Storms on the Surface of Mars (Invited Presentation)

Although solar activity is declining as the Sun approaches solar minimum, a series of large solar storms occurred in September 2017 that impacted both Earth and Mars. This was the largest event seen on the surface of Mars since the landing of the Mars Science Laboratory (MSL) in 2012, and was also observed as GLE72 on Earth, making it the first event observed to produce a Ground Level Enhancement (GLE) on 2 planets at the same time! Due to the modulating effect of the Martian atmosphere and the magnetic cloud associated with the Coronal Mass Ejection (CME), the structure and intensity of the spectra observed at the surface are complex. We present the observations of this event obtained with the Radiation Assessment Detector (RAD) on MSL and discuss the implications for our understanding of such events and for mitigating the risk of space radiation and space weather for future human exploration.