CZ-4B R/B

CZ-4B R/B is a spent rocket body associated with China, launched on 2014-12-07 from Taiyuan, China on the ZY1-4 launch. After 12 years in orbit, it continues to be tracked by global surveillance networks. It orbits in Low Earth Orbit (LEO) at altitudes between 453 km and 647 km with an inclination of 98.5°. It travels at approximately 27,320 km/h (7.59 km/s), completing one full orbit every 96 minutes — that’s roughly 15.06 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. Spent rocket bodies like CZ-4B R/B are among the largest pieces of uncontrolled space debris and are priority targets for collision avoidance manoeuvres and future active debris removal efforts.

CZ-4B R/B orbits at an average altitude of 550 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 CZ-4B R/B’s average altitude, there are currently 3,342 active payloads and 363 tracked debris or rocket body fragments — notable neighbours include STARLINK-1184, STARLINK-1276, ONEWEB-0050. This makes it one of the more crowded altitude bands, containing roughly 19.1% of all active satellites. With an inclination of 98.5°, CZ-4B R/B 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 1,221 active satellites in total, of which 161 share a similar altitude band with CZ-4B R/B.