CZ-4 DEB

CZ-4 DEB is a tracked piece of space debris attributed to China, launched on 2003-10-21 from Taiyuan, China on the ZY-1-2 launch. With over 23 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 662 km and 732 km with an inclination of 98.7°. It travels at approximately 27,035 km/h (7.51 km/s), completing one full orbit every 99 minutes — that’s roughly 14.59 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. As orbital debris, CZ-4 DEB poses a potential collision risk to operational satellites in nearby orbits and is continuously monitored by the U.S. Space Surveillance Network and other tracking systems.

CZ-4 DEB orbits at an average altitude of 697 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-4 DEB’s average altitude, there are currently 274 active payloads and 1,416 tracked debris or rocket body fragments — notable neighbours include TERRA, AQUA, LANDSAT 9. With an inclination of 98.7°, CZ-4 DEB passes over latitudes between 98.7°N and 98.7°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 1,218 active satellites in total, of which 58 share a similar altitude band with CZ-4 DEB.