OV1-20/OV1-21 AKM

OV1-20/OV1-21 AKM 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 710 km and 791 km with an inclination of 87.6°. It travels at approximately 26,933 km/h (7.48 km/s), completing one full orbit every 100 minutes — that’s roughly 14.43 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~25–100 years. Spent rocket bodies like OV1-20/OV1-21 AKM are among the largest pieces of uncontrolled space debris and are priority targets for collision avoidance manoeuvres and future active debris removal efforts.

OV1-20/OV1-21 AKM orbits at an average altitude of 751 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 OV1-20/OV1-21 AKM’s average altitude, there are currently 412 active payloads and 2,112 tracked debris or rocket body fragments — notable neighbours include LANDSAT 9. With an inclination of 87.6°, OV1-20/OV1-21 AKM 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 13,206 active satellites in total, of which 183 share a similar altitude band with OV1-20/OV1-21 AKM.