The GPM mission is one of the next generation of satellite-based Earth science missions that study global precipitation (rain, snow, ice). GPM Constellation is a joint mission with the Japan Aerospace Exploration Agency (JAXA) and other international partners. Building upon the success of the Tropical Rainfall Measuring Mission (TRMM), it initiates the measurement of global precipitation, a key climate factor. Its science objectives are: to improve ongoing efforts to predict climate by providing near-global measurement of precipitation, its distribution, and physical processes; to improve the accuracy of weather and precipitation forecasts through more accurate measurement of rain rates and latent heating; and to provide more frequent and complete sampling of the Earth's precipitation. GPM was launched February 27, 2014.