S-NPP

Mission Specification

The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project, or NPP, was launched on October 28, 2011 to collect and distribute remotely-sensed land, ocean, and atmospheric observations for the meteorological, oceanographic, terrestrial and global climate change communities. It aims to provide data continuity of these measurements from existing Earth-observing missions such as Aqua, Terra and Aura.  The NPP satellite is the first in a series designed to provide critical data to improve short-term weather forecasts and increase understanding of long-term climate change.

On January 24, 2012 at the annual meeting of the American Meteorological Society in New Orleans, NASA has renamed its newest Earth-observing satellite in honor of the late Verner E. Suomi, a meteorologist at the University of Wisconsin who is recognized widely as "the father of satellite meteorology." The NPOESS Preparatory Project (NPP) then became the Suomi National Polar-orbiting Partnership satellite, or Suomi NPP (S-NPP).

S-NPP is a pilot mission for the Joint Polar Satellite System (JPSS), which is the next generation polar-orbiting operational environmental satellite system for the USA. Onboard the S-NPP satellite, there are five state-of-the-art instruments/sensors: The Advanced Technology Microwave Sounder (ATMS), Visible Infrared Imaging Radiometer Suite (VIIRS), Cross-track Infrared Sounder (CrIS), Ozone Mapping Profiler Suite (OMPS), and Clouds and the Earth's Radiant Energy System (CERES).  

Like the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Terra/Aqua, VIIRS is a multi-disciplinary sensor providing data for the ocean, land, aerosol, and cloud research and operational users. VIIRS spectral coverage allows for ocean data products similar to those from the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) and MODIS while providing slightly better spatial resolution (750 m) and improved global temporal coverage (one day).  From the perspective of sea surface temperature (SST), VIIRS extends and improves upon the decadal series of measurements initiated by the Advanced Very High Resolution Radiometer (AVHRR) and MODIS.

The JPSS-1 (NOAA-20) is the second mission in the JPSS series, which is scheduled to launch in the fourth quarter of 2017. For the rest of JPSS series, their schedules are also planned and can be found at the NOAA Launch-Schedule webpage: http://www.jpss.noaa.gov/launch_schedule.html. 

Platform/Instrument Specification

Orbit Characteristics

Sun synchronous, near-polar orbit

Equatorial Crossing
 
10:30 a.m., descending node
Inclination
 
98.74°
Altitude
 
824 km
Period
 
101 minutes
Semi-major axis
 
7204 km
Repeat cycle
 
16 days (quasi 8-day)

Launch Statistics

Vehicle
 
Alliance Delta-2-7920-10 vehicle
Site
 
Vandenberg Air Force Base in California
Launch Date
 
Oct. 28, 2011 @ 2:48:01.828 a.m. PDT

Vital Statistics

Spacecraft
 
~2200 kg
Power
 
2,285 watts average
Size
 
1.3 m x 1.3 m x 4.2 m
Storage
 
268 GB
Downlink Data Rate
 
300 Mbit/s in X-band, 128 Kbit/s in S-band
Mission Life
 
5 years (available consumables for 7 years)
VIIRS Instrument

VIIRS is the largest instrument onboard NPP, weighing in at 556 pounds (252 kilograms). Its data, collected from 22 channels across the electromagnetic spectrum, will be used to observe the Earth’s surface, including fires, ice, ocean color, vegetation, clouds, and land and sea surface temperatures.

The VIIRS instrument is a whiskbroom scanning radiometer with a field of regard of 112.56 degree in the cross-track direction. At a nominal altitude of 824 km, the swath width is 3060 km, providing full daily coverage both in the day and night side of the Earth. VIIRS's 22 spectral bands cover the spectrum between 0.412 µm and 12.01 µm, including 16 moderate resolution bands (M-bands) with a spatial resolution of 750 m at nadir, 5 imaging resolution bands (I-bands) – 375 m at nadir, and one panchromatic DNB with a 750 m spatial resolution throughout the scan. The M-bands include 11 Reflective Solar Bands (RSB) and 5 Thermal Emissive Bands (TEBs). The I-bands include 3 RSBs and 2 TEBs. 

VIIRS provides capabilities to produce higher resolution and more accurate measurements of sea surface temperature (SST) than currently available from the heritage AVHRR instrument on POES, as well as provide an operational capability for ocean-color observations and a variety of derived ocean-color products. The SST is one of the key VIIRS ocean products and is included in the GHRSST project. 

Instrument Specifications

Spectral Bands
     Visible/Near IR:                                    9 plus day/night pan band
     Mid-Wave IR:                                                                           8
     Long-Wave IR:                                                                         4
Imaging Optics:                        19.1 cm aperture, 114 cm focal length
Orbit Average Power:                                                         200 Watts
Weight:                                                                                 275 kg
Data Acquisition Parameters:
    Scanned Swath:                                                     ±56°, 3000 km
    Horizontal Sample Interval on Ground:        <1.6 km @ end of scan
    Data Quantization:       12 bit –14 bit A/D converters for lower noise
    Data Rate:                                                        10.5 Mbps (max.)