SL-8 R/B

SL-8 R/B is a spent rocket body associated with Russia (CIS), launched on 1978-06-21 from PKMTR on the Strela-2M launch. With over 48 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 731 km and 766 km with an inclination of 74.1°. It travels at approximately 26,937 km/h (7.48 km/s), completing one full orbit every 100 minutes — that’s roughly 14.43 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~25–100 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 749 km in the mid-LEO band, where atmospheric drag is minimal but radiation exposure remains manageable. Objects at this altitude persist for decades to centuries, making debris mitigation critical. This regime is popular for remote sensing constellations and scientific instruments that need stable, long-duration orbits. Within ±50 km of SL-8 R/B’s average altitude, there are currently 356 active payloads and 1,955 tracked debris or rocket body fragments — notable neighbours include LANDSAT 9. With an inclination of 74.1°, SL-8 R/B passes over latitudes between 74.1°N and 74.1°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 1,287 active satellites in total, of which 47 share a similar altitude band with SL-8 R/B.