1. Department of Geological Sciences, Stockholm University, Stockholm, Sweden.
2. Department of Geological Sciences, University of Canterbury, Christchurch, New Zealand.
3. Aix Marseille Université, CNRS, LAM (Laboratoire d'Astrophysique de Marseille) UMR 7326, Marseille, France.
4. Space Science and Engineering Division, Southwest Research Institute, San Antonio, Texas, USA.
5. European Space Agency, Noordwijk, the Netherlands.