YIJIAN

YIJIAN is an active satellite operated by Shanghai Engineering Center for Microsatellites (China), launched on 2016-12-21 from Jiuquan, China. After 10 years in orbit, it continues to be tracked by global surveillance networks. It orbits in Low Earth Orbit (LEO) at altitudes between 677 km and 705 km with an inclination of 98.5°. It travels at approximately 27,046 km/h (7.51 km/s), completing one full orbit every 99 minutes — that’s roughly 14.61 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. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~10–25 years. Orbital Radar tracks YIJIAN in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

YIJIAN orbits at an average altitude of 691 km in a sun-synchronous orbit (SSO), a specialised subset of LEO where the orbital plane precesses to maintain a constant angle relative to the Sun. This provides consistent lighting conditions on every pass — essential for Earth observation, weather monitoring and environmental science. Within ±50 km of YIJIAN’s average altitude, there are currently 291 active payloads and 1,350 tracked debris or rocket body fragments — notable neighbours include TERRA, AQUA, LANDSAT 9. With an inclination of 98.5°, YIJIAN passes over latitudes between 98.5°N and 98.5°S, providing near-global coverage including the polar regions. Polar and near-polar orbits are used for reconnaissance, weather monitoring and Earth-observation missions that need to image every part of the planet. China operates approximately 1,218 active satellites in total, of which 60 share a similar altitude band with YIJIAN.