Complex sentence: The Polar-orbiting Operational Environmental Satellite (POES) is a constellation of polar orbiting weather satellites funded by the National Oceanic and Atmospheric Administration (NOAA) and the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT).
Split into simpler sentences: The Polar-orbiting Operational Environmental Satellite (POES) operates a constellation of weather satellites in polar orbits around the Earth. It is a joint effort between the National Oceanic and Atmospheric Administration (NOAA) and the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT).