1. Istituto di Astrofisica e Planetologia Spaziali (IAPS/INAF), 00133 Rome, Italy
2. Royal Observatory of Belgium (ROB-ORB), B-1180 Brussels, Belgium
3. Earth and Life Institute, Secteur des Sciences et Technologies, Université Catholique de Louvain-la-Neuve (UCLouvain), 3, place Louis Pasteur/L4.03.08, B-1348 Louvain-la-Neuve, Belgium
4. Royal Belgian Institute for Space Aeronomy (IASB-BIRA), B-1180 Brussels, Belgium
5. School of Physical Sciences, The Open University (OU), Milton Keynes MK7 6AA, UK
6. Instituto de Astrofìsica de Andalucia (IAA), Consejo Superior de Investigaciones Científicas (CSIC), 18008 Granada, Spain
7. Agenzia Spaziale Italiana (ASI), 00133 Rome, Italy