SJ-31

SJ-31 is an active satellite operated by China, launched on 2026-06-16 from Xichang, China. As a relatively recent addition to the catalogue, its orbital elements are well-characterised. It orbits in Medium Earth Orbit (MEO) at altitudes between 178 km and 35,820 km with an inclination of 63.5°. It travels at approximately 14,559 km/h (4.04 km/s), completing one full orbit every 10 hours 31 minutes — that’s roughly 2.28 orbits per day. Its orbital eccentricity of 0.7313 gives it a noticeably elliptical path, with significant altitude variation between perigee and apogee. Orbital Radar tracks SJ-31 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

SJ-31 orbits at an average altitude of 17,999 km in Medium Earth Orbit, the region between LEO and GEO (2,000–35,786 km). MEO’s higher altitude gives each satellite a much larger ground footprint than LEO, meaning fewer spacecraft are needed for global coverage — but signal latency is higher and radiation from the Van Allen belts is a significant design constraint. Within ±50 km of SJ-31’s average altitude, there are currently 2 active payloads and 9 tracked debris or rocket body fragments. This is a relatively sparse altitude band, containing less than 1% of all active satellites. With an inclination of 63.5°, SJ-31 passes over latitudes between 63.5°N and 63.5°S, covering most populated land masses in both hemispheres. This mid-inclination band balances global coverage with efficient launch energy requirements. China operates approximately 1,220 active satellites in total, of which 2 share a similar altitude band with SJ-31.