SHIYAN 21 (SY-21)

SHIYAN 21 (SY-21) is an active satellite operated by China, launched on 2022-12-16 from Xichang, China on the SJ2013 launch. It orbits in Low Earth Orbit (LEO) at altitudes between 464 km and 505 km with an inclination of 36.0°. It travels at approximately 27,451 km/h (7.63 km/s), completing one full orbit every 94 minutes — that’s roughly 15.27 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~1–3 years. Orbital Radar tracks SHIYAN 21 (SY-21) in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

SHIYAN 21 (SY-21) orbits at an average altitude of 485 km in the core of Low Earth Orbit, the most heavily utilised altitude band. The balance of moderate drag (limiting debris accumulation) and short signal path (enabling low-latency links and high-resolution imaging) makes this regime the default for most commercial and government missions. Within ±50 km of SHIYAN 21 (SY-21)’s average altitude, there are currently 8,107 active payloads and 219 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 46.5% of all active satellites. With an inclination of 36.0°, SHIYAN 21 (SY-21) passes over latitudes between 36.0°N and 36.0°S, covering the tropical and temperate zones where most of the world’s population resides. Low-to-mid inclination orbits are efficient to reach from equatorial and mid-latitude launch sites. China operates approximately 1,217 active satellites in total, of which 189 share a similar altitude band with SHIYAN 21 (SY-21).