SL-6 R/B(2)

SL-6 R/B(2) is a spent rocket body associated with Russia (CIS), launched on 1999-12-27 from PKMTR on the Oko launch. With over 27 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Medium Earth Orbit (MEO) at altitudes between 152 km and 38,077 km with an inclination of 62.3°. It travels at approximately 14,237 km/h (3.95 km/s), completing one full orbit every 11 hours 15 minutes — that’s roughly 2.13 orbits per day. Its orbital eccentricity of 0.7441 gives it a noticeably elliptical path, with significant altitude variation between perigee and apogee. Spent rocket bodies like SL-6 R/B(2) are among the largest pieces of uncontrolled space debris and are priority targets for collision avoidance manoeuvres and future active debris removal efforts.

SL-6 R/B(2) orbits at an average altitude of 19,115 km in Medium Earth Orbit, the region between LEO and GEO (2,000–35,786 km). MEO’s higher altitude gives each satellite a much larger ground footprint than LEO, meaning fewer spacecraft are needed for global coverage — but signal latency is higher and radiation from the Van Allen belts is a significant design constraint. Within ±50 km of SL-6 R/B(2)’s average altitude, there are currently 143 active payloads and 48 tracked debris or rocket body fragments — notable neighbours include COSMOS 1413 (GLONASS), COSMOS 1414 (GLONASS), COSMOS 1415 (GLONASS). With an inclination of 62.3°, SL-6 R/B(2) passes over latitudes between 62.3°N and 62.3°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 1,288 active satellites in total, of which 143 share a similar altitude band with SL-6 R/B(2).