YAOGAN-4

YAOGAN-4 is an active satellite operated by China, launched on 2008-12-01 from Jiuquan, China. After 18 years in orbit, it continues to be tracked by global surveillance networks. It orbits in Low Earth Orbit (LEO) at altitudes between 610 km and 630 km with an inclination of 97.9°. It travels at approximately 27,183 km/h (7.55 km/s), completing one full orbit every 97 minutes — that’s roughly 14.83 orbits per day. Its near-polar, sun-synchronous orbit means it passes over any given point on Earth at approximately the same local solar time, ideal for consistent Earth observation lighting conditions. It is part of the Resource constellation group. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~10–25 years. Orbital Radar tracks YAOGAN-4 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

YAOGAN-4 operates in a sun-synchronous orbit (SSO), a special subset of LEO where the orbital plane precesses to keep a constant angle relative to the Sun. This means the satellite crosses any given latitude at approximately the same local solar time on every pass, providing consistent lighting conditions — essential for Earth observation, weather monitoring and environmental science. SSO orbits typically sit between 600 and 800 km altitude with inclinations near 97–99°.