Institution: | * Space Science Department of ESA, Keplerlaan 1, NL-2200 AG, Noordwijk, The Netherlands ** Institute of Space Research, Austrian Academy of Sciences, Inffeldgasse 12, A-8010, Graz, Austria *** Austrian Research Centre Seibersdorf, A-2444, Seibersdorf, Austria ? Norwegian Defense Research Establishment, P.O. Box 25, N-2007, Kjeller, Norway |