ESA´s Frequency and Timing systems for deep space operations and Radio Science investigations

Following the successful operation of the first Deep Space Antenna (DSA1) in New Norcia, Australia [1] and the recent inauguration of the 2^nd Station (DSA2) in Cebreros, Spain [2], the European Space Agency (ESA) is currently expanding its Deep Space tracking capabilities, the next facility to be constructed in Kourou, French Guyana. Deep space operations and research impose demanding phase stability on ground station equipment, high frequency stability of the reference system and excellent phase noise of the distributed reference signal. The combination of these aspects is certainly unique for Frequency and Timing systems. An outline of ESA´s past and future design and development activities in support of advanced F&T systems is given, which demonstrates ESA´s commitment to continuously improve its support of Deep Space Missions. The paper describes the 2nd generation Hydrogen-Maser based Frequency and Timing System in Cebreros, which has been optimized for a high stability and low phase noise 100 MHz distribution system. The architectural design and its operational aspects are presented. The actual performance is given in terms of · Allan Deviation (<; 1E-15 between 1000 and 10000 seconds), · Phase Noise (-102 dBc at 1 Hz offset for 100 MHz) · Long-Term Stability (1.2e-15/day). The paper puts the present performance of ESA´s stations in perspective with future mission requirements, which traditionally arise from state-of-the-art Radio Science research. The evolution path to meet future mission demands, which might arise from ambitious projects like BepiColombo [3], is presented.