1. Space Science and Technology Centre; School of Earth and Planetary Sciences; Curtin University; Perth WA 6102 Australia
2. Natural History Museum; Burgring 7 A-1010 Vienna Austria
3. Jacobs-JETS; Astromaterials Research and Exploration Science Division; NASA Johnson Space Center; Houston Texas 77058 USA
4. NASA Astrobiology Institute; Department of Geoscience; University of Wisconsin-Madison; Madison Wisconsin 53706 USA