Following the achievements of the European GOCE mission, which produced a high-resolution static global model of Earth’s gravity field, the European Space Agency has initiated several studies on a Next Generation Gravity Mission (NGGM). The primary objective of NGGM is to observe temporal variations of Earth’s gravitational field over long time scales with an unprecedented level of accuracy. The mission consists of two satellites flying in a long-distance formation along a low-altitude inclined orbit, with each satellite is controlled to achieve drag- free condition. Gravity field anomalies will be estimated from variations in the inter-satellite distance, measured by means of laser interferometry and corrected through precise measurements of non-gravitational accelerations.