1. Department of Earth, Atmospheric and Planetary Sciences Massachusetts Institute of Technology Cambridge MA USA
2. Tartu Observatory University of Tartu Tõravere Estonia
3. Department of Geology Bryn Mawr College Bryn Mawr PA USA
4. American Museum of Natural History New York NY USA
5. Department of Physics Ludwig Maximilian University München Germany
6. Jet Propulsion Laboratory California Institute ofTechnology Pasadena CA USA