SL-12 R/B(2)

SL-12 R/B(2) is a spent rocket body associated with Russia (CIS), launched on 1983-12-29 from Baikonur, Kazakhstan on the Uragan No. 14L launch. With over 43 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Medium Earth Orbit (MEO) at altitudes between 18,888 km and 19,239 km with an inclination of 66.3°. It travels at approximately 14,251 km/h (3.96 km/s), completing one full orbit every 11 hours 13 minutes — that’s roughly 2.14 orbits per day. Spent rocket bodies like SL-12 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-12 R/B(2) orbits at an average altitude of 19,064 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-12 R/B(2)’s average altitude, there are currently 3 active payloads and 37 tracked debris or rocket body fragments — notable neighbours include COSMOS 1413 (GLONASS), COSMOS 1415 (GLONASS), COSMOS 1521 (GLONASS). This is a relatively sparse altitude band, containing less than 1% of all active satellites. With an inclination of 66.3°, SL-12 R/B(2) passes over latitudes between 66.3°N and 66.3°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 1,287 active satellites in total, of which 3 share a similar altitude band with SL-12 R/B(2).