1. Laboratory for Extraterrestrial Physics; NASA Goddard Space Flight Center; Greenbelt Maryland USA
2. Space and Atmospheric Physics; Imperial College; London UK
3. Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
4. Mullard Space Science Laboratory; Holmbury St. Mary; Dorking England UK
5. Centre d'Etude Spatiale des Rayonnements; Toulouse France