The Global Precipitation Measurement (GPM) mission is an international collaboration designed to unify and advance precipitation measurements from space for scientific research and societal applications. Precipitation plays a crucial role in water resources management, climate change, and Earth's energy and biogeochemical cycles. Traditional surface-based measurements have limitations, especially over large regions and oceans, where in situ data are scarce. GPM aims to address these challenges by deploying a constellation of research and operational microwave sensors, including the GPM Core Observatory, which carries a dual-frequency radar (DPR) and a conical-scanning microwave imager (GMI). These instruments will provide more accurate and frequent measurements of precipitation, particularly light rainfall and snow, extending the measurement range beyond that of previous missions like TRMM. The mission will improve understanding of global water and energy cycles, enhance storm tracking and prediction, and support applications such as flood and landslide forecasting, freshwater monitoring, and crop prediction. GPM's data will be used in various scientific programs and international initiatives, contributing to climate change research and policy-making. The mission's success will depend on accurate intersatellite calibration and the development of advanced precipitation retrieval algorithms, which will be validated through ground-based and satellite-based observations.The Global Precipitation Measurement (GPM) mission is an international collaboration designed to unify and advance precipitation measurements from space for scientific research and societal applications. Precipitation plays a crucial role in water resources management, climate change, and Earth's energy and biogeochemical cycles. Traditional surface-based measurements have limitations, especially over large regions and oceans, where in situ data are scarce. GPM aims to address these challenges by deploying a constellation of research and operational microwave sensors, including the GPM Core Observatory, which carries a dual-frequency radar (DPR) and a conical-scanning microwave imager (GMI). These instruments will provide more accurate and frequent measurements of precipitation, particularly light rainfall and snow, extending the measurement range beyond that of previous missions like TRMM. The mission will improve understanding of global water and energy cycles, enhance storm tracking and prediction, and support applications such as flood and landslide forecasting, freshwater monitoring, and crop prediction. GPM's data will be used in various scientific programs and international initiatives, contributing to climate change research and policy-making. The mission's success will depend on accurate intersatellite calibration and the development of advanced precipitation retrieval algorithms, which will be validated through ground-based and satellite-based observations.