GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) was a European Space Agency (ESA) satellite mission dedicated to mapping the Earth's gravity field and modeling the geoid with unprecedented accuracy and spatial resolution. GOCE carried the first-ever space-borne gradiometer, an instrument designed to measure the gradient of the gravity field with extremely high accuracy. It consisted of three pairs of accelerometers arranged in three dimensions. The satellite utilized ion thrusters to counteract atmospheric drag, maintaining an exceptionally stable orbit to ensure the accuracy of gravity measurements.