SL-8 R/B

SL-8 R/B is a spent rocket body associated with Russia (CIS), launched on 1972-07-20 from Plesetsk Cosmodrome, Russia on the Strela-1M launch. 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 1,491 km and 1,599 km with an inclination of 74.0°. It travels at approximately 25,546 km/h (7.10 km/s), completing one full orbit every 117 minutes — that’s roughly 12.31 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is thousands of 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 1,545 km in the uppermost reaches of Low Earth Orbit. At this altitude, orbital decay is effectively zero without active deorbiting, and coverage footprints are significantly larger than lower LEO, though at the cost of higher latency. Within ±50 km of SL-8 R/B’s average altitude, there are currently 88 active payloads and 387 tracked debris or rocket body fragments. 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 71 share a similar altitude band with SL-8 R/B.