The Suomi National Polar-orbiting Partnership (Suomi NPP), previously known as the National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) and NPP-Bridge, is a weather satellite operated by the United States

National Oceanic and Atmospheric Administration The National Oceanic and Atmospheric Administration (NOAA ) is an American scientific and regulatory agency charged with Weather forecasting, forecasting weather, monitoring oceanic and atmospheric conditions, Hydrography, charting the seas, ...

(NOAA). It was launched in 2011 and is currently in operation. Suomi NPP was originally intended as a pathfinder for the National Polar-orbiting Operational Environmental Satellite System (NPOESS) program, which was to have replaced NOAA's Polar Operational Environmental Satellites (POES) and the U.S. Air Force's Defense Meteorological Satellite Program (DMSP). Suomi NPP was launched in 2011 after the cancellation of NPOESS to serve as a stop-gap between the POES satellites and the

Joint Polar Satellite System The Joint Polar Satellite System (JPSS) is the latest generation of U.S. polar-orbiting, non-geosynchronous, environmental satellites. JPSS will provide the global environmental data used in numerical weather prediction models for forecasts, and ...

(JPSS) which will replace them. Its instruments provide climate measurements that continue prior observations by

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

Earth Observing System The Earth Observing System (EOS) is a program of NASA comprising a series of artificial satellite missions and scientific instruments in Earth orbit designed for long-term global observations of the land surface, biosphere, earth's atmosphere, at ...

(EOS).

Name

The satellite is named after Verner E. Suomi, a Finnish-American meteorologist at the

University of Wisconsin–Madison The University of Wisconsin–Madison (University of Wisconsin, Wisconsin, UW, UW–Madison, or simply Madison) is a public land-grant research university in Madison, Wisconsin, United States. It was founded in 1848 when Wisconsin achieved st ...

. The name was announced on 24 January 2012, three months after the satellite's launch.

History

Suomi NPP was intended to bridge the gap between the old

(EOS) and the new JPSS system by flying new instruments, on a new satellite bus, using a new ground data network. Originally planned for launch five years earlier as a joint

NOAA The National Oceanic and Atmospheric Administration (NOAA ) is an American scientific and regulatory agency charged with forecasting weather, monitoring oceanic and atmospheric conditions, charting the seas, conducting deep-sea exploratio ...

/ DoD project, NPP was to be a pathfinder mission for the larger National Polar-orbiting Operational Environmental Satellite System (NPOESS) until DoD participation in the larger project was dissolved. The project continued as a civilian weather forecasting replacement for the NOAA Polar Operational Environmental Satellites (POES) series, and ensured continuity of climate measurements begun by the

(EOS) of NASA.

Launch

The spacecraft was launched on 28 October 2011 from Space Launch Complex-2W (SLC-2W) at

Vandenberg Space Force Base Vandenberg Space Force Base , previously Vandenberg Air Force Base, is a United States Space Force Base in Santa Barbara County, California. Established in 1941, Vandenberg Space Force Base is a space launch base, launching spacecraft from the ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

by a United Launch Alliance

Delta II Delta II was an expendable launch system, originally designed and built by McDonnell Douglas, and sometimes known as the Thorad Delta 1. Delta II was part of the Delta rocket family, derived directly from the Delta 3000, and entered service in ...

in the 7920-10 configuration (Extra Extended Long Tank with RS-27A engine first stage, 9 GEM-40 solid rocket motors, type 2 second stage with Aerojet AJ10-118K engine, no third stage and a 10-foot fairing). Additionally, the rocket deployed five

CubeSat A CubeSat is a class of small satellite with a form factor of cubes. CubeSats have a mass of no more than per unit,, url=https://static1.squarespace.com/static/5418c831e4b0fa4ecac1bacd/t/5f24997b6deea10cc52bb016/1596234122437/CDS+REV14+2020-07-3 ...

s as a part of NASA ELaNa III manifest. The satellite was placed into a

Sun-synchronous orbit A Sun-synchronous orbit (SSO), also called a heliosynchronous orbit, is a nearly polar orbit around a planet, in which the satellite passes over any given point of the planet's surface at the same local mean solar time. More technically, it is ...

(SSO) above the

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

. File:Orbit path - Suomi NPP descending - night.png, Suomi NPP's descending orbital path

Spacecraft

The Suomi NPP spacecraft has been built and integrated by BATC (Ball Aerospace and Technologies Corporation) of Boulder, Colorado (NASA/GSFC contract award in May 2002). The platform design is a variation of BCP 2000 (Ball Commercial Platform) bus of BATC of ICESat and CloudSat heritage. The spacecraft consists of an

aluminum Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...

honeycomb structure. The ADCS (Attitude Determination and Control Subsystem) provides three-axis stabilization using four

reaction wheel A reaction wheel (RW) is an electric motor attached to a flywheel, which, when its rotation speed is changed, causes a counter-rotation proportionately through conservation of angular momentum. A reaction wheel can rotate only around its center ...

s for fine attitude control, three torquer bars for momentum unloading, thrusters for coarse attitude control (such as during large-angle slews for orbital maintenance), two

star tracker A star tracker is an optical device that measures the positions of stars using photocells or a camera. As the positions of many stars have been measured by astronomers to a high degree of accuracy, a star tracker on a satellite or spacecraft may ...

s for fine attitude determination, three

gyroscope A gyroscope (from Ancient Greek γῦρος ''gŷros'', "round" and σκοπέω ''skopéō'', "to look") is a device used for measuring or maintaining Orientation (geometry), orientation and angular velocity. It is a spinning wheel or disc in ...

s for attitude and attitude rate determination between star tracker updates, two Earth sensors for safe-mode attitude control, and coarse Sun sensors for initial attitude acquisition, all monitored and controlled by the spacecraft controls a computer. ADCS provides real-time attitude knowledge of 10 arcsec (1 sigma) at the spacecraft navigation reference base, real-time spacecraft position knowledge of 25 m (1 sigma), and attitude control of 36 arcsec (1 sigma). The EPS (Electrical Power Subsystem) uses

gallium arsenide Gallium arsenide (GaAs) is a III-V direct band gap semiconductor with a Zincblende (crystal structure), zinc blende crystal structure. Gallium arsenide is used in the manufacture of devices such as microwave frequency integrated circuits, monoli ...

(GaAs)

solar cell A solar cell, also known as a photovoltaic cell (PV cell), is an electronic device that converts the energy of light directly into electricity by means of the photovoltaic effect.

s to generate an average power of about 2 kW (EOL). The solar array rotates once per orbit to maintain a nominally normal orientation to the Sun. In addition, a single-wing solar array is mounted on the anti-solar side of the spacecraft; its function is to preclude thermal input into the sensitive cryo radiators of the Visible Infrared Imaging Radiometer Suite (VIIRS) and Cross-track Infrared Sounder (CrIS) instruments. A regulated 28 ±6 VDC power bus distributes energy to all spacecraft subsystems and instruments. A nickel–hydrogen battery (NiH) system provides power for

eclipse An eclipse is an astronomical event which occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another body or by having another body pass between it and the viewer. This alignment of three ...

phase operations. The spacecraft has an on-orbit design lifetime of five years (available consumables for seven years). The spacecraft dry mass is about 1400 kg. NPP is designed to support controlled reentry at the end of its mission life (via propulsive maneuvers to lower the orbit perigee to approximately 50 km and target any surviving debris for open ocean entry). NPP is expected to have sufficient debris that survives reentry so as to require controlled reentry to place the debris in a pre-determined location in the ocean.

Instruments

The Suomi NPP is the first in a new generation of satellites intended to replace the

(EOS) satellites, which were launched from 1997 to 2009. The satellite orbits the Earth about 14 times each day. Its five imaging systems include:

Visible Infrared Imaging Radiometer Suite (VIIRS)

The Visible Infrared Imaging Radiometer Suite (VIIRS) is the largest instrument aboard of Suomi-NPP (National Polar-Orbiting Operational Environmental Satellite System ( NPOESS) Preparatory Project). It collects radiometric imagery in visible and

infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...

wavelengths of the land, atmosphere, ice, and ocean. It will survey broad swaths of the land, oceans, and air, enabling scientists to monitor everything from

phytoplankton Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater Aquatic ecosystem, ecosystems. The name comes from the Greek language, Greek words (), meaning 'plant', and (), mea ...

and other organisms in the sea, vegetation and forest cover, and the amount of sea ice at the poles. Data from VIIRS, collected from 22 channels across the

electromagnetic spectrum The electromagnetic spectrum is the full range of electromagnetic radiation, organized by frequency or wavelength. The spectrum is divided into separate bands, with different names for the electromagnetic waves within each band. From low to high ...

, will also be used to observe active fires, ocean color, sea surface temperature, and other surface features.

Ozone Mapping and Profiler Suite (OMPS)

The

Ozone Mapping and Profiler Suite Ozone Mapping and Profiler Suite (OMPS), is a suite of instruments built by Ball Aerospace that measure the global distribution of ozone and, less frequently, how it is distributed vertically within the stratosphere. The suite flies on the Suomi ...

(OMPS) measures the

ozone layer The ozone layer or ozone shield is a region of Earth's stratosphere that absorption (electromagnetic radiation), absorbs most of the Sun's ultraviolet radiation. It contains a high concentration of ozone (O3) in relation to other parts of the a ...

in our

upper atmosphere Upper atmosphere is a collective term that refers to various layers of the atmosphere of the Earth above the troposphere and corresponding regions of the atmospheres of other planets, and includes: * The mesosphere, which on Earth lies between th ...

tracking the status of global ozone distributions, including the

ozone hole Ozone depletion consists of two related events observed since the late 1970s: a lowered total amount of ozone in Earth, Earth's upper atmosphere, and a much larger springtime decrease in stratospheric ozone (the ozone layer) around Earth's polar ...

. It also monitors ozone levels in the

troposphere The troposphere is the lowest layer of the atmosphere of Earth. It contains 80% of the total mass of the Atmosphere, planetary atmosphere and 99% of the total mass of water vapor and aerosols, and is where most weather phenomena occur. From the ...

. OMPS extends out 40-year long record ozone layer measurements while also providing improved vertical resolution compared to previous operational instruments. Closer to the ground, OMPS's measurements of harmful ozone improve air quality monitoring and when combined with cloud predictions; help to create the Ultraviolet index. OMPS has two sensors, both new designs, composed of three advanced hyperspectral-imaging spectrometers.

Clouds and the Earth's Radiant Energy System (CERES)

The Clouds and the Earth's Radiant Energy System (CERES) will be used to study the Earth's radiation budget. Monitoring the amount of energy emitted and reflected by the planet, it measures both

solar energy Solar energy is the radiant energy from the Sun's sunlight, light and heat, which can be harnessed using a range of technologies such as solar electricity, solar thermal energy (including solar water heating) and solar architecture. It is a ...

reflected by the

and heat emitted by our planet. This solar and thermal energy are key parts of the Earth's radiation budget. CERES instrument continues a multi-year record of the amount of energy entering and exiting from the top of the

atmosphere of Earth The atmosphere of Earth is composed of a layer of gas mixture that surrounds the Earth's planetary surface (both lands and oceans), known collectively as air, with variable quantities of suspended aerosols and particulates (which create weather ...

. It will provide scientists with needed long-term, stable data sets to make accurate projections of global climate change.

Cross-track Infrared Sounder (CrIS)

The Cross-track Infrared Sounder (CrIS) has 1305 spectral channels and will produce high-resolution, three-dimensional temperature, pressure, and moisture profiles. It measures continuous channels in the infrared region and has the ability to measure temperature profiles with improved accuracy over its predecessors. These profiles will be used to enhance weather forecasting models and will facilitate both short- and long-term weather forecasting. Over longer timescales, they will help improve understanding of climate phenomena.

Advanced Technology Microwave Sounder (ATMS)

The Advanced Technology Microwave Sounder (ATMS), works in conjunction with the Cross-track Infrared Sounder (CrIS) to make detailed vertical profiles of atmospheric pressure, heat, and moisture. ATMS, a cross-track scanner with 22 channels, provides sounding observations needed to retrieve profiles of atmospheric temperature and moisture for civilian operational weather forecasting as well as continuity of these measurements for climate monitoring purposes. CrIS will operate at infrared wavelengths, while ATMS will operate at much shorter, microwave, wavelengths.

Mission

The VIIRS sensor on board the spacecraft acquired its first measurements of Earth on 21 November 2011.VIIRS First Light
NASA also released a high resolution blue marble image of the Earth showing most of

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

, which was created by NASA oceanographer Norman Kuring using data obtained on 4 January 2012 by the Visible Infrared Imager Radiometer Suite (VIIRS), one of five imaging systems aboard the satellite. That date was chosen because it was a fairly sunny day in most of North America. , beyond the initial 5-year mission, the spacecraft continues to operate.

Gallery

File:Delta II and NPP after service structure rollback.jpg, Delta II rocket carrying NPP. File:NPP Launch.ogv, NPP launch video File:US East Coast VIR 2011326 large.jpg, First image acquired by the VIIRS sensor. File:A Sky View of Earth From Suomi NPP.jpg, This composite image of southern Africa and the surrounding oceans was captured by six orbits of the satellite. File:2020augderecho-suomi-outages-animated.gif, Iowa power outage File:Lac-Megantic derailment from space.jpg, Lac-Megantic derailment