nasa’s global precipitation measurement mission (gpm) uses satellites to measure earth's rain and snowfall for the benefit of mankind. launched by nasa and jaxa on feb. 27th, 2014, gpm is an international mission that sets the standard for spaceborne precipitation measurements. using a network of satellites united by the gpm core observatory, gpm expands on the legacy of the tropical rainfall measuring mission (trmm) by providing high quality estimates of earth’s rain and snowfall every 30 minutes.