Shuai Li¹, Paul G Lucey¹, Abigail Fraeman², Andrew R Poppe³, Vivian Zheng Sun², Dana Hurley⁴ and Peter H Schultz⁵, (1)Hawai'i Institute of Geophysics and Planetology, Honolulu, HI, United States, (2)Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States, (3)Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States, (4)Applied Physics Laboratory Johns Hopkins, Laurel, MD, United States, (5)Brown University, Providence, RI, United States