1. Université Côte d’Azur, ICN, 06108 Nice, France
2. European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), Keplerlaan 1, P. O. Box 299, NL-2200 AG Noordwijk, The Netherlands
3. Thales Alenia Space, 5 Allée des Gabians, 06156 Cannes la Bocca, France