In 1994, the United States merged its two polar-orbiting environmental satellite programs operated separately by the Department of Commerce and the Department of Defense into a single system which was called the National Polar-orbiting Operational Environmental Satellite System (NPOESS). NPOESS was sponsored by the Department of Defense, the Department of Commerce and the National Aeronautics and Space Administration and was managed by an Integrated Program Office (IPO) that was populated by personnel from the three sponsoring agencies. A risk reduction mission named the NPOESS Preparatory Project (NPP) preceded the first NPOESS satellite, planned for early 2013.

On February 1, 2010, the Office of Science, Technology and Policy announced a major restructuring of the NPOESS program to resolve conflicting perspectives and priorities among the three agencies and minimize potential lapses in capability resulting from NPOESS delays. The restructure terminated the NPOESS program on 30 September 2010 and assigned primary responsibility for the 1330 and 1730 Local Time Ascending Node (LTAN) orbits to the National Oceanic and Atmospheric Administration (NOAA) and the Department of Defense (DoD) respectively. The NOAA program is called the Joint Polar Satellite System (JPSS) and the DoD program is called the Defense Weather Satellite System (DWSS). The two programs are expected to use the Command, Control, Communications and ground processing systems that were developed for NPOESS. The follow-on programs are also expected to use the advanced sensors that were developed for NPOESS. The United States need for data from the 2130 LTAN orbit will be fulfilled through a partnership with the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT).

The NPOESS Preparatory Project (NPP) will be completed as originally planned. NPP will carry the following five sensors that were developed for the NPOESS program: - Visible/Infrared Imager Radiometer Suite (VIIRS) that will provide advanced imaging and radiometric capabilities. - Cross-track Infrared Sounder (CrIS) that will provide improved atmospheric moisture and temperature profiles in clear conditions. - Advanced Technology Microwave Sounder (ATMS) that will provide improved atmospheric moisture and temperature profiles in cloudy conditions. - Ozone Mapping and Profiler Suite (OMPS) that will provide improved vertical and horizontal measurements of the distribution of ozone in the Earth's atmosphere. - Clouds and the Earth's Radiant Energy System (CERES) sensor that will continue precise, calibrated global measurements of the earth's radiation budget

NPP will provide on-orbit testing and validation of sensors, algorithms, ground-based operations, and data processing systems that will be used in the operational JPSS mission. By the middle of the decade the first JPSS spacecraft will be launched into the afternoon orbit to provide significantly improved operational capabilities and benefits to satisfy critical civil and national security requirements for space-based, remotely sensed environmental data. The last satellite in the JPSS mission constellation is expected to continue operations until about 2037. A mid-morning orbit will be occupied by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Meteorological Operational (MetOp) spacecraft. The joint constellation of JPSS, DWSS and MetOp satellites will provide the international community global coverage from advanced atmospheric imaging and sounding instruments with a data refresh rate of approximately four to six hours. Several instruments on JPSS will improve capabilities for climate monitoring and provide measurements of a significant number of essential climate variables.