COSMOS 1521 (GLONASS)

COSMOS 1521 (GLONASS) is an active satellite operated by Russian Space Forces (Russia (CIS)), launched on 1983-12-29 from Baikonur, Kazakhstan. With over 43 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Medium Earth Orbit (MEO) at altitudes between 18,910 km and 19,232 km with an inclination of 66.3°. It travels at approximately 14,249 km/h (3.96 km/s), completing one full orbit every 11 hours 13 minutes — that’s roughly 2.14 orbits per day. It is part of the Glo Ops constellation group. Orbital Radar tracks COSMOS 1521 (GLONASS) in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

COSMOS 1521 (GLONASS) orbits at an average altitude of 19,071 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 1521 (GLONASS)’s average altitude, there are currently 4 active payloads and 41 tracked debris or rocket body fragments — notable neighbours include COSMOS 1413 (GLONASS), COSMOS 1415 (GLONASS), COSMOS 2431 (GLONASS). This is a relatively sparse altitude band, containing less than 1% of all active satellites. With an inclination of 66.3°, COSMOS 1521 (GLONASS) passes over latitudes between 66.3°N and 66.3°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 1,285 active satellites in total, of which 4 share a similar altitude band with COSMOS 1521 (GLONASS).