ZHANGHENG 1

ZHANGHENG 1 is an active satellite operated by China Earthquake Administration/Italian Institute for Nuclear Physics (China), launched on 2018-02-02 from Jiuquan, China on the CSES launch. It orbits in Low Earth Orbit (LEO) at altitudes between 491 km and 515 km with an inclination of 97.7°. It travels at approximately 27,414 km/h (7.61 km/s), completing one full orbit every 95 minutes — that’s roughly 15.21 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 ~3–10 years. Orbital Radar tracks ZHANGHENG 1 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

ZHANGHENG 1 orbits at an average altitude of 503 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 ZHANGHENG 1’s average altitude, there are currently 9,647 active payloads and 244 tracked debris or rocket body fragments — notable neighbours include STARLINK-1017, STARLINK-1039, STARLINK-1047. This makes it one of the more crowded altitude bands, containing roughly 55.2% of all active satellites. With an inclination of 97.7°, ZHANGHENG 1 passes over latitudes between 97.7°N and 97.7°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 1,221 active satellites in total, of which 193 share a similar altitude band with ZHANGHENG 1.