SL-8 R/B

SL-8 R/B is a spent rocket body associated with Russia (CIS), launched on 1971-11-20 from Plesetsk Cosmodrome, Russia on the Sfera launch. After more than 55 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 1,177 km and 1,211 km with an inclination of 74.0°. It travels at approximately 26,132 km/h (7.26 km/s), completing one full orbit every 109 minutes — that’s roughly 13.18 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~500–1,000 years. Spent rocket bodies like SL-8 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-8 R/B orbits at an average altitude of 1,194 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-8 R/B’s average altitude, there are currently 872 active payloads and 279 tracked debris or rocket body fragments — notable neighbours include ONEWEB-0012, ONEWEB-0010, ONEWEB-0008. With an inclination of 74.0°, SL-8 R/B passes over latitudes between 74.0°N and 74.0°S, covering most populated land masses in both hemispheres. This mid-inclination band balances global coverage with efficient launch energy requirements. Russia (CIS) operates approximately 1,537 active satellites in total, of which 16 share a similar altitude band with SL-8 R/B.