Influence of Mars Topography on Radiation Dose Detected by the Mars Science Laboratory and Assessment of Mars Surface Albedo Radiation

Abstract

The Radiation Assessment Detector (RAD) on the Curiosity rover has been characterizing the Martian surface radiation field since 2012. The dose observed by RAD is influenced by a variety of factors, including an essential one, the terrain. After parking near Murray Buttes in September 2016 where it first detected a ∼5% decrease in dose rate, the rover has passed a series of other interesting terrains where we find decreases in the dose rate reaching 19%. This radiation reduction is due to extra shielding provided by the nearby surface structure, confirming the potential use of surface structures for radiation protection of humans on Mars. Combining a zenith‐angle‐dependent radiation model and the rover panoramic visibility map we calculate the downward radiation dose that RAD should observe under different topographic shielding conditions. This allows us to further evaluate the terrain‐generated albedo dose at different locations. We finally estimate that on a flat surface the albedo radiation is between ∼18% and 24% of the total surface dose. This study contributes to developing a realistic terrain‐based radiation map which is important for future Mars explorers.