1. Mullard Space Science Laboratory; UCL; London UK
2. Department of Climate and Space Sciences and Engineering; University of Michigan; Ann Arbor Michigan USA
3. Centre for Planetary Sciences; UCL/Birkbeck; London UK
4. Department of Physics; Lancaster University; Lancaster UK
5. Office for Space Research and Technology; Academy of Athens; Athens Greece
6. Planetary Science Institute; Tucson Arizona USA
7. Department of Physics and Astronomy; University of Montana; Missoula Montana USA
8. Max-Planck-Institut für Sonnensystemforschung; Göttingen Germany
9. Southwest Research Institute; San Antonio Texas USA