SL-3 R/B

SL-3 R/B is a spent rocket body associated with Russia (CIS), launched on 1981-07-10 from Baikonur Cosmodrome, Kazakhstan on the Meteor-Priroda No. 2-4 launch. With over 45 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 451 km and 464 km with an inclination of 97.6°. It travels at approximately 27,505 km/h (7.64 km/s), completing one full orbit every 94 minutes — that’s roughly 15.36 orbits per day. Its near-polar, sun-synchronous orbit means it passes over any given point on Earth at approximately the same local solar time, ideal for consistent Earth observation lighting conditions. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~1–3 years. Spent rocket bodies like SL-3 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-3 R/B orbits at an average altitude of 458 km in a sun-synchronous orbit (SSO), a specialised subset of LEO where the orbital plane precesses to maintain a constant angle relative to the Sun. This provides consistent lighting conditions on every pass — essential for Earth observation, weather monitoring and environmental science. Within ±50 km of SL-3 R/B’s average altitude, there are currently 10,560 active payloads and 167 tracked debris or rocket body fragments — notable neighbours include ISS (ZARYA), STARLINK-1017, STARLINK-1039. This makes it one of the more crowded altitude bands, containing roughly 56.5% of all active satellites. With an inclination of 97.6°, SL-3 R/B passes over latitudes between 97.6°N and 97.6°S, providing near-global coverage including the polar regions. Polar and near-polar orbits are used for reconnaissance, weather monitoring and Earth-observation missions that need to image every part of the planet. Russia (CIS) operates approximately 1,514 active satellites in total, of which 60 share a similar altitude band with SL-3 R/B.