SL-6 R/B

SL-6 R/B is a spent rocket body associated with Russia (CIS), launched on 1995-12-28 from Baikonur, Kazakhstan on the IRS-1C launch. With over 31 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 798 km and 805 km with an inclination of 98.7°. It travels at approximately 26,837 km/h (7.45 km/s), completing one full orbit every 101 minutes — that’s roughly 14.27 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. Its near-circular orbit (eccentricity close to zero) means it maintains a very consistent altitude throughout each revolution. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~100–500 years. Spent rocket bodies like SL-6 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-6 R/B orbits at an average altitude of 802 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-6 R/B’s average altitude, there are currently 443 active payloads and 2,306 tracked debris or rocket body fragments — notable neighbours include NOAA 20, ONEWEB-0179, ONEWEB-0455. With an inclination of 98.7°, SL-6 R/B passes over latitudes between 98.7°N and 98.7°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 1,286 active satellites in total, of which 82 share a similar altitude band with SL-6 R/B.