SL-3 DEB

SL-3 DEB is a tracked piece of space debris attributed to Russia (CIS), launched on 1988-04-20 from Baikonur, Kazakhstan on the Resurs-O1 No. 2L launch. With over 38 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 478 km and 519 km with an inclination of 97.5°. It travels at approximately 27,423 km/h (7.62 km/s), completing one full orbit every 95 minutes — that’s roughly 15.22 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 ~1–3 years. As orbital debris, SL-3 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.

SL-3 DEB orbits at an average altitude of 499 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 SL-3 DEB’s average altitude, there are currently 9,165 active payloads and 238 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 52.6% of all active satellites. With an inclination of 97.5°, SL-3 DEB passes over latitudes between 97.5°N and 97.5°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. Russia (CIS) operates approximately 1,285 active satellites in total, of which 58 share a similar altitude band with SL-3 DEB.