Testing of the prototype PARIS receiver, put together by Spain’s Institute of Space Sciences (IEEC-CSIC). The prototype was flown on the Aalto University research aircraft from Helsinki Airport across the Gulf of Finland for two hours on 11 November 2011. PARIS antennas are fitted to the top and underside of the aircraft. From left to right: Erkka Rohue (pilot), ESA engineer Manuel Martín-Neira, inventor of the PARIS concept, Juan Carlos Arco and Fran Fabra (IEEC crew scientists), Pertti Lehtinen (co-pilot), Juha Kainulainen (Aalto University engineer) and Antonio Rius (chief scientist, IEEC).