OV1-21 R/B

OV1-21 R/B is a spent rocket body associated with United States, launched on 1971-08-07 from Vandenberg Space Force Base, United States on the OAR-901 launch. After more than 55 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 771 km and 891 km with an inclination of 87.6°. It travels at approximately 26,782 km/h (7.44 km/s), completing one full orbit every 102 minutes — that’s roughly 14.18 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~100–500 years. Spent rocket bodies like OV1-21 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.

OV1-21 R/B orbits at an average altitude of 831 km in the upper LEO band, where atmospheric drag is negligible and objects can persist for centuries to millennia. This altitude is used by broadband constellations like OneWeb and by scientific missions requiring stable orbits far from the densest debris bands. Within ±50 km of OV1-21 R/B’s average altitude, there are currently 293 active payloads and 2,453 tracked debris or rocket body fragments — notable neighbours include NOAA 20, ONEWEB-0455. With an inclination of 87.6°, OV1-21 R/B passes over latitudes between 87.6°N and 87.6°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. United States operates approximately 13,279 active satellites in total, of which 77 share a similar altitude band with OV1-21 R/B.