SL-12 R/B(2)

SL-12 R/B(2) is a spent rocket body associated with Russia (CIS), launched on 1983-03-23 from Baikonur, Kazakhstan on the 1A No. 602 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 24,618 km and 177,077 km with an inclination of 76.8°. It travels at approximately 6,941 km/h (1.93 km/s), completing one full orbit every 97.1 hours — that’s roughly 0.25 orbits per day. Its orbital eccentricity of 0.7110 gives it a noticeably elliptical path, with significant altitude variation between perigee and apogee. At geostationary altitude, there is no meaningful atmospheric drag — this object will remain in orbit indefinitely unless actively deorbited. 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 100,848 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. With an inclination of 76.8°, SL-12 R/B(2) passes over latitudes between 76.8°N and 76.8°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 1,287 active satellites in total.