1. Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, Washington DC 20015, USA
2. NASA Johnson Space Center, Mailcode XI2, 2101 NASA Parkway, Houston, Texas 77058, USA
3. Washington University in St. Louis, Department of Earth and Planetary Sciences and Institute for Materials Science and Engineering, 1 Brookings Drive, CB 1169, St. Louis, MO 63130-4899, USA