SL-3 R/B

SL-3 R/B is a spent rocket body associated with Russia (CIS), launched on 1964-08-28 from Baikonur Cosmodrome, Kazakhstan on the Meteor 11F614 No. 1 launch. After more than 62 years in orbit, it is one of the longest-surviving objects in the space catalogue. It orbits in Low Earth Orbit (LEO) at altitudes between 634 km and 743 km with an inclination of 65.1°. It travels at approximately 27,051 km/h (7.51 km/s), completing one full orbit every 99 minutes — that’s roughly 14.61 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~10–25 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 689 km in the mid-LEO band, where atmospheric drag is minimal but radiation exposure remains manageable. Objects at this altitude persist for decades to centuries, making debris mitigation critical. This regime is popular for remote sensing constellations and scientific instruments that need stable, long-duration orbits. Within ±50 km of SL-3 R/B’s average altitude, there are currently 339 active payloads and 1,435 tracked debris or rocket body fragments — notable neighbours include TERRA, AQUA, ONEWEB-0179. With an inclination of 65.1°, SL-3 R/B passes over latitudes between 65.1°N and 65.1°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 1,537 active satellites in total, of which 20 share a similar altitude band with SL-3 R/B.