NPOES 1, 2

NPOES C1 [NG]

NPOES C2 [NG]

The National Polar-orbiting Operational Environmental Satellite System (NPOESS) will converge existing polar-orbiting satellite systems under a single national program. Polar-orbiting satellites observe Earth from space. They collect and disseminate data on Earth's weather, atmosphere, oceans, land, and near-space environment. The polar orbiters are able to monitor the entire planet and provide data for long-range weather and climate forecasts. The program is managed by the tri-agency Integrated Program Office (IPO) utilizing personnel from the Department of Commerce, Department of Defense and NASA. The current NPOESS mandate extends to the year 2018. The satellites in the NPOESS are called NPOES (National Polar-orbiting Operational Environmental Satellite).

In addition to cost-effectiveness the National Polar-orbiting Operational Satellite System (NPOESS) increases the timeliness and accuracy of severe weather event forecasts. Advanced microwave imagery-sounding data products will lead to improved prediction of ocean surface wind speed and direction, a major factor in the phenomenon called weather. The knowledge obtained from NPOESS data reduces the potential loss of human life and property resulting from severe weather. An improved hurricane landfall forecast skill will save an estimated $1 million per mile of coastline that does not have to be evacuated. Support for general aviation, agriculture, and maritime activities aimed at improved early warnings will mitigate the devastating effects of floods through disaster planning and response. For the Military, NPOESS shifts the tactical and strategic focus from "coping with weather" to anticipating and exploiting atmospheric and space environmental conditions.

To achieve its mission NPOESS has undertaken a far-reaching program of sensor development and satellite transition and evolution to provide complete coverage of meteorological conditions for civil, military, and scientific purposes while cutting operational costs dramatically. Cost reductions are achieved by converging existing polar-orbiting programs from Department of Defense, Department of Commerce and NASA into a single system. NPOESS satellites in three orbital planes will replace the two-satellite DMSP constellation and the two-satellite POES (NOAA) constellation. The data will be processed into Raw Data Records (RDRs), Sensor Data Records (SDRs), and Environmental Data Records (EDRs) for use by a number of operational communities.

Instruments in the NPOESS are:

• VIIRS Visible/Infrared Imager/Radiometer Suite
  Collects visible and infrared radiometric data of the Earth's atmosphere, ocean, and land surfaces. Data types include atmospheric, clouds, Earth radiation budget, land/water and sea surface temperature, ocean color, and low light imagery.
• CMIS Conical Microwave Imager/Sounder.
  Collects global microwave radiometry and sounding data to produce microwave imagery and other meteorological and oceanographic data.
• CrIS Crosstrack Infrared Sounder.
  Measures Earth's radiation to determine the vertical distribution of temperature, moisture, and pressure in the atmosphere.
• GPSOS Global Positioning System Occultation Sensor
  Measures the refraction of radiowave signals from the GPS and Russia's Global Navigation Satellite System (GLONASS) to characterize the ionosphere.
• OMPS Ozone Mapping and Profiler Suite
  Collects data to permit the calculation of the vertical and horizontal distribution of ozone in the Earth's atmosphere.
• SESS Space Environment Sensor Suite.
  Collects data related to the neutral and charged particles, electron and magnetic fields, and optical signatures of aurora.
• APS Aerosol Polarimeter Sensor.
  The purpose of the APS is to retrieve specified aerosol and cloud parameters using multispectral photopolarimetry.
• ATMS Advanced Technology Microwave Sounder (currently under development by NASA)
  In conjunction with CrIS, global observations of temperature and moisture profiles at high temporal resolution (~ daily).
• DCS Data Collection System
  The NPOESS DCS will be similar to the Argos DCS which resides on NOAA's current POES and measures environmental factors such as atmospheric temperature and pressure, and the velocity and direction of the ocean and wind currents.
• ERBS Earth Radiation Budget Sensor
  NPOESS will measure Earth Radiation Budget parameters using instruments similar to the ERBE and CERES heritage instruments:
• RADAR Altimeter
  NPOESS will use a RADAR altimeter similar to that used on Jason-1 which is used to measure sea surface topography ocean surface topography to an accuracy of 4.2 cm.
• SARSAT Search and Rescue Satellite Aided Tracking
  The SARSAT system uses NOAA satellites in low-Earth and geostationary orbits to detect and locate aviators, mariners, and land-based users in distress.
• TSIS Total Solar Irradiance Sensor
  TSIS is a total solar irradiance monitor plus a 0.2- 2 micron solar spectral irradiance monitor.

A design review in 2006 removed several climate instruments from the program: Removed from NPOESS were the Total Solar Irradiance Sensor (TSIS), the Earth Radiation Budget Sensor (ERBS), the Ocean Altimeter (ALT), and the Ozone Mapping and Profiler Suite Limb Subsystem (OMPS-Limb). The decision has since been made to fly OMPS-Limb on the NPOESS Preparatory Project (NPP) spacecraft set to launch in 2011. During the review, the number of NPOES satellites was also reduced from six to four. Concerns remain about possible continued problems with NPOESS' many sensors, particularly the Visible Infrared Imaging Radiometer Suite (VIIRS) and Cross-track Infrared Sounder (CrIS). Problems with the Raytheon-built VIIRS were a major contributor to NPOESS' cost growth, and CrIS experienced a structural failure during vibration testing last fall.

In February 2010 it was decided to stop the development of the NPOESS due to the massive cost overruns and tri-agency management problems. The afternoon satellites will be replaced by the JPSS (Joint Polar Satellite System) managed by NASA and NOAA, while the morning satellites will be provided by the military DWSS (Defense Weather Satellite System) system. As with the NOAA and DMSP series, the agencies will use a joint ground system.