1. LESIA, Observatoire de Paris-Meudon, Meudon Cedex, France
2. Department Electrical & Computer Engineering, University of Idaho, Moscow, ID, USA
3. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
4. University of Michigan, Ann Arbor, MI, USA
5. ESA/ESTEC, Noordwijk, The Netherlands
6. Dipartment di Fisica, University degli Studi di Roma, Rome, Italy