[1] Danish Space Res Inst, DK-2100 Copenhagen O, Denmark
[2] Metorex Int Oy, Espoo 02631, Finland
[3] Univ Helsinki, Observ, FIN-00014 Helsinki, Finland
[4] Space Res Ctr, PL-00716 Warsaw, Poland
[5] CNR, Inst Astrofis, I-00133 Rome, Italy
[6] ENEA, Frascati UTS Fus, I-00045 Frascati, Italy
[7] IASF Bologna, I-40129 Bologna, Italy
[8] Univ Ferrara, Dipartmento Fis, I-44100 Ferrara, Italy
[9] Univ Valencia, GACE, Valencia 46071, Spain
[10] Stockholm Univ, S-10691 Stockholm, Sweden
[11] Copernicus Astron Ctr, PL-00716 Warsaw, Poland
[12] CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain
[13] Alenia Spazio, Space Div, I-10146 Turin, Italy
[14] ESOC, D-64293 Darmstadt, Germany
[15] European Space Agcy, Estec, NL-2200 AG Noordwijk, Netherlands
[16] MPI Extraterr Phys, D-85748 Garching, Germany
[17] ISDC, Versoix, Switzerland
[18] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA