SL-3 DEB

SL-3 DEB is a tracked piece of space debris attributed to Russia (CIS), launched on 1972-06-30 from PKMTR. After more than 54 years in orbit, it is one of the longest-surviving objects in the space catalogue. It orbits in Low Earth Orbit (LEO) at altitudes between 850 km and 922 km with an inclination of 81.2°. It travels at approximately 26,680 km/h (7.41 km/s), completing one full orbit every 103 minutes — that’s roughly 14.02 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~100–500 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 886 km in the upper LEO band, where atmospheric drag is negligible and objects can persist for centuries to millennia. This altitude is used by broadband constellations like OneWeb and by scientific missions requiring stable orbits far from the densest debris bands. Within ±50 km of SL-3 DEB’s average altitude, there are currently 179 active payloads and 1,577 tracked debris or rocket body fragments. With an inclination of 81.2°, SL-3 DEB passes over latitudes between 81.2°N and 81.2°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 1,286 active satellites in total, of which 48 share a similar altitude band with SL-3 DEB.