GRACE – Gravity Recovery And Climate Experiment

GRACE (Gravity Recovery And Climate Experiment) was a joint US-German satellite mission (2002-2017) designed to map Earth’s gravity field with high precision and monitor how it changes over time. It consisted of two satellites flying ~220 km apart in a polar orbit, measuring distance changes between them caused by variations in Earth’s mass distribution beneath them. These measurements allow detection of mass changes due to melting ice sheets, groundwater depletion, ocean circulation, and solid Earth processes. The mission produces monthly gravity field models to track temporal changes.

More Info: https://geodesy.science/item/satellite-gravimetry/