// ORBITAL LOGISTICS AND PROPULSION TERM
Sun-Synchronous
Describes an orbit where a satellite crosses the equator at the same local solar time on every pass, providing consistent lighting conditions for observations.
TECHNICAL DEFINITION
Sun-synchronous describes an orbital characteristic where the orbital plane precesses at the same rate as the Earth orbits the Sun, ensuring that the satellite passes over any given latitude at the same local solar time, which is highly advantageous for Earth observation missions requiring consistent illumination.
BACKGROUND
A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, peaking in number at an altitude around 800 km (500 mi), while the farthest in LEO, before medium Earth orbit (MEO), have an altitude of 2,000 kilometers, about one-third of the radius of Earth and near the beginning of the inner Van Allen radiation belt.
READ MORE ON WIKIPEDIASYNONYMS & ALIASES
- Solar-synchronous
- SSO-type
- constant lighting orbit
USAGE NOTE
Many remote sensing and weather satellites are placed in sun-synchronous orbits to standardize image acquisition conditions.
DEVELOPERS
Organizations developing technology related to Sun-Synchronous.
As a leading launch service provider, SpaceX frequently launches satellites into sun-synchronous orbits for various commercial and government customers, enabling consistent Earth observation and scientific missions.
Rocket Lab specializes in small satellite launches, with its Electron rocket often deploying payloads into sun-synchronous orbits for Earth observation, remote sensing, and technology demonstration missions.
Planet Labs operates the world's largest constellation of Earth observation satellites, many of which are in sun-synchronous orbits to provide consistent, daily imagery of the Earth's landmass.
Maxar Technologies designs, builds, and operates advanced Earth observation satellites, such as the WorldView series, which often utilize sun-synchronous orbits for high-resolution imaging with consistent lighting conditions.
Airbus Defence and Space is a major developer and manufacturer of Earth observation satellites, including those for the Copernicus program, with many missions utilizing sun-synchronous orbits for global monitoring and remote sensing.
Capella Space operates a constellation of synthetic aperture radar (SAR) satellites primarily in sun-synchronous orbits, providing all-weather, day-and-night Earth observation capabilities.
ESA develops and operates numerous Earth observation missions, including the Sentinel satellites for the Copernicus program, which frequently employ sun-synchronous orbits to ensure regular and consistent global data collection for environmental monitoring.