SL-3 R/B

SL-3 R/B is a spent rocket body associated with Russia (CIS), launched on 1983-02-16 from Plesetsk Cosmodrome, Russia on the Tselina-D launch. With over 43 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 401 km and 420 km with an inclination of 81.1°. It travels at approximately 27,600 km/h (7.67 km/s), completing one full orbit every 93 minutes — that’s roughly 15.52 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~1–3 years. Spent rocket bodies like SL-3 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.

SL-3 R/B orbits at an average altitude of 411 km in the core of Low Earth Orbit, the most heavily utilised altitude band. The balance of moderate drag (limiting debris accumulation) and short signal path (enabling low-latency links and high-resolution imaging) makes this regime the default for most commercial and government missions. Within ±50 km of SL-3 R/B’s average altitude, there are currently 847 active payloads and 99 tracked debris or rocket body fragments — notable neighbours include ISS (ZARYA), STARLINK-1008, STARLINK-1012. With an inclination of 81.1°, SL-3 R/B passes over latitudes between 81.1°N and 81.1°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 1,514 active satellites in total, of which 32 share a similar altitude band with SL-3 R/B.