COSMOS 991

COSMOS 991 is an active satellite operated by Russia (CIS), launched on 1978-02-28 from PKMTR. With over 48 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 950 km and 1,002 km with an inclination of 83.0°. It travels at approximately 26,517 km/h (7.37 km/s), completing one full orbit every 105 minutes — that’s roughly 13.77 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~100–500 years. Orbital Radar tracks COSMOS 991 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

COSMOS 991 orbits at an average altitude of 976 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 COSMOS 991’s average altitude, there are currently 287 active payloads and 965 tracked debris or rocket body fragments. With an inclination of 83.0°, COSMOS 991 passes over latitudes between 83.0°N and 83.0°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 1,285 active satellites in total, of which 163 share a similar altitude band with COSMOS 991.