The National Polar-Orbiting Operational Environmental Satellite System (NPOESS) is a new satellite system intended to provide global coverage from low-earth-orbit (LEO), combining and improving the capabilities of the U.S. Polar Operational Environmental Satellite system (POES) and the Defense Meteorological Satellite Program (DMSP). The new integrated system will provide a wealth of environmental information to government agencies, environmental and atmospheric scientists, and private industry. This presentation reviews the current NPOESS program, with particular emphasis on its capabilities and potential benefits this system can offer in support of aviation and its role in the Next Generation Air Transportation System (NextGen). The NPOESS instrumentation most critical in supporting aviation weather include the Visible/Infrared Imager and Radiometer Suite (VIIRS), Cross track Infrared Sounder (CrIS), space weather sensors, and the Conical Scanning Microwave Imager/Sounder (CMIS). An overview of NPOESS satellite synergy, Nunn-McCurdy review impact, and expected improvements in aviation weather hazard detection with NPOESS deployment will be shown.