Propulsion technologies in the frame of ESA’s next generation gravity mission
In the first decade of XXI century, European Space Agency (ESA) has extensively promoted studies in order to establish scientific requirements, identify the most appropriate measurement techniques, start the associated technology developments, and define the system scenarios for a Next Generation Gravity Mission (in brief, NGGM). Such a mission will make use of the Low-Low Satellite-to-Satellite Tracking (LL-SST) technique to monitor the temporal variations of the Earth gravity field over a long time span, like the GRACE (Gravity Recovery and Climate Experiment) mission, but with much higher spatial resolution comparable to that provided by the GOCE mission (where GOCE stands for Gravity field and steady-state Ocean Circulation Explorer), and with improved temporal resolution.