SL-8 R/B

SL-8 R/B is a spent rocket body associated with Russia (CIS), launched on 1971-03-18 from Plesetsk Cosmodrome, Russia on the DS-P1-M No. 3 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 946 km and 1,009 km with an inclination of 65.8°. It travels at approximately 26,514 km/h (7.36 km/s), completing one full orbit every 105 minutes — that’s roughly 13.76 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~100–500 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 978 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 369 active payloads and 1,179 tracked debris or rocket body fragments. With an inclination of 65.8°, SL-8 R/B passes over latitudes between 65.8°N and 65.8°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 200 share a similar altitude band with SL-8 R/B.