COSMOS 1851

COSMOS 1851 is an active satellite operated by Russia (CIS), launched on 1987-06-12 from PKMTR. With over 39 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Medium Earth Orbit (MEO) at altitudes between 7,831 km and 32,554 km with an inclination of 70.9°. It travels at approximately 13,945 km/h (3.87 km/s), completing one full orbit every 11 hours 58 minutes — that’s roughly 2.00 orbits per day. Its orbital eccentricity of 0.4654 gives it a noticeably elliptical path, with significant altitude variation between perigee and apogee. Orbital Radar tracks COSMOS 1851 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

COSMOS 1851 orbits at an average altitude of 20,193 km in Medium Earth Orbit, the region between LEO and GEO (2,000–35,786 km). MEO’s higher altitude gives each satellite a much larger ground footprint than LEO, meaning fewer spacecraft are needed for global coverage — but signal latency is higher and radiation from the Van Allen belts is a significant design constraint. Within ±50 km of COSMOS 1851’s average altitude, there are currently 104 active payloads and 14 tracked debris or rocket body fragments — notable neighbours include GPS BIIR-5 (PRN 22), GPS BIIR-8 (PRN 16), GPS BIIR-11 (PRN 19). With an inclination of 70.9°, COSMOS 1851 passes over latitudes between 70.9°N and 70.9°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 1,286 active satellites in total, of which 57 share a similar altitude band with COSMOS 1851.