1. Department of Earth & Planetary Sciences and Planetary Geosciences Institute; University of Tennessee; Knoxville; Tennessee; 37996; USA
2. Johns Hopkins University Applied Physics Laboratory; Laurel; Maryland; 20273; USA
3. U.S. Geological Survey; Denver; Colorado; 80225; USA
4. Department of Earth and Planetary Sciences and McDonnell Center for Space Sciences; Washington University; St. Louis; Missouri; 63130; USA