COSMOS 861

COSMOS 861 is an active satellite operated by Soviet Navy (Russia (CIS)), launched on 1976-10-21 from Baikonur Cosmodrome, Kazakhstan on the US-A reactor launch. After more than 50 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 930 km and 985 km with an inclination of 64.9°. It travels at approximately 26,550 km/h (7.37 km/s), completing one full orbit every 104 minutes — that’s roughly 13.82 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~100–500 years. Orbital Radar tracks COSMOS 861 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

COSMOS 861 orbits at an average altitude of 958 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 861’s average altitude, there are currently 444 active payloads and 1,290 tracked debris or rocket body fragments. With an inclination of 64.9°, COSMOS 861 passes over latitudes between 64.9°N and 64.9°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 1,552 active satellites in total, of which 206 share a similar altitude band with COSMOS 861.