COSMOS 729

COSMOS 729 is an active satellite operated by Soviet Navy (Russia (CIS)), launched on 1975-04-22 from Plesetsk Cosmodrome, Russia on the Zaliv launch. After more than 51 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 969 km and 1,004 km with an inclination of 83.0°. It travels at approximately 26,498 km/h (7.36 km/s), completing one full orbit every 105 minutes — that’s roughly 13.74 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~100–500 years. Orbital Radar tracks COSMOS 729 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

COSMOS 729 orbits at an average altitude of 987 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 729’s average altitude, there are currently 403 active payloads and 1,116 tracked debris or rocket body fragments. With an inclination of 83.0°, COSMOS 729 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 1,552 active satellites in total, of which 195 share a similar altitude band with COSMOS 729.