SL-6 R/B(2)

SL-6 R/B(2) is a spent rocket body associated with Russia (CIS), launched on 1990-06-21 from PKMTR on the Oko launch. With over 36 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 525 km and 584 km with an inclination of 62.8°. It travels at approximately 27,312 km/h (7.59 km/s), completing one full orbit every 96 minutes — that’s roughly 15.04 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~3–10 years. 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 555 km in the core of Low Earth Orbit, the most heavily utilised altitude band. The balance of moderate drag (limiting debris accumulation) and short signal path (enabling low-latency links and high-resolution imaging) makes this regime the default for most commercial and government missions. Within ±50 km of SL-6 R/B(2)’s average altitude, there are currently 3,232 active payloads and 390 tracked debris or rocket body fragments — notable neighbours include STARLINK-1184, STARLINK-1276, ONEWEB-0050. This makes it one of the more crowded altitude bands, containing roughly 18.5% of all active satellites. With an inclination of 62.8°, SL-6 R/B(2) passes over latitudes between 62.8°N and 62.8°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, of which 40 share a similar altitude band with SL-6 R/B(2).