Sun-Synchronous Orbit (SSO)
Earth-observation and weather satellites that need consistent lighting, such as Landsat, the Sentinels, and Terra/Aqua.
Overview
A near-polar low orbit whose plane precesses to keep a constant angle to the Sun, so a satellite passes over each location at the same local solar time — ideal for consistent-illumination Earth imaging.
Typical uses
Earth-observation and weather satellites that need consistent lighting, such as Landsat, the Sentinels, and Terra/Aqua.
Satellites in this orbit
14 satellites and constellations modelled in this orbit.
- Planet Dove (Flock)Active
Planet Labs' fleet of shoebox-sized Dove CubeSats that image the entire land surface of the Earth daily at medium resolution.
OperatorPlanet LabsOrbitSSOSizeHundreds of small CubeSats - AquaActive
NASA's Earth Observing System afternoon satellite, focused on the water cycle — precipitation, evaporation, clouds, and ocean properties.
OperatorNASAOrbitSun-synchronousLaunched2002 - CALIPSORetired
A NASA–CNES mission using a space lidar to profile aerosols and thin clouds in Earth's atmosphere, flying in the A-Train formation.
OperatorNASA / CNESOrbitSun-synchronousLaunched2006 - CloudSatRetired
A NASA mission carrying a cloud-profiling radar that measured the vertical structure of clouds to study their role in climate.
OperatorNASAOrbitSun-synchronousLaunched2006 Japan's greenhouse-gases observing satellite — the first satellite dedicated to monitoring atmospheric carbon dioxide and methane from space — operated by JAXA with Japan's National Institute for Environmental Studies.
OperatorJAXA / NIESOrbitSun-synchronousLaunched2009- Landsat 1Retired
The first satellite of the Landsat program, which began the longest continuous record of Earth's land surface from space.
OperatorNASAOrbitSun-synchronousLaunched1972 - Landsat 8Active
A NASA/USGS Landsat satellite carrying the Operational Land Imager and Thermal Infrared Sensor, continuing the multi-decade land-imaging record.
OperatorUSGSOrbitSun-synchronousLaunched2013 - Landsat 9Active
The latest Landsat satellite, launched in 2021 to work in tandem with Landsat 8 for an eight-day global revisit of the land surface.
OperatorUSGSOrbitSun-synchronousLaunched2021 - NOAA-20Active
The first satellite of NOAA's Joint Polar Satellite System, providing global polar-orbiting weather and environmental observations.
OperatorNOAAOrbitSun-synchronousLaunched2017 - Sentinel-1Active
A Copernicus radar-imaging mission providing all-weather, day-and-night synthetic-aperture radar imagery of land and ocean.
OperatorESAOrbitSun-synchronousLaunched2014 - Sentinel-2Active
A Copernicus optical-imaging mission delivering high-resolution multispectral imagery for land monitoring, agriculture, and disaster response.
OperatorESAOrbitSun-synchronousLaunched2015 - Sentinel-3Active
A Copernicus mission monitoring ocean and land surface temperature, colour, and topography for climate and marine services.
OperatorESAOrbitSun-synchronousLaunched2016 - TerraActive
NASA's flagship Earth Observing System morning satellite, carrying instruments including MODIS and ASTER to study land, ocean, and atmosphere.
OperatorNASAOrbitSun-synchronousLaunched1999 - WorldView-3Active
A Maxar very-high-resolution commercial Earth-imaging satellite used for mapping, defence, and analytics.
OperatorMaxar TechnologiesOrbitSun-synchronousLaunched2014
Sources
The primary and reference sources this topic draws on.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.
- ESAEuropean Space Agency
European missions, observatories, and space science imagery.