COSMOS 2251 DEB

COSMOS 2251 DEB is a tracked piece of space debris attributed to Russia (CIS), launched on 1993-06-16 from PKMTR on the Strela-2M launch. With over 33 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 311 km and 343 km with an inclination of 73.8°. It travels at approximately 27,771 km/h (7.71 km/s), completing one full orbit every 91 minutes — that’s roughly 15.81 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is months to ~1 year. As orbital debris, COSMOS 2251 DEB poses a potential collision risk to operational satellites in nearby orbits and is continuously monitored by the U.S. Space Surveillance Network and other tracking systems.

COSMOS 2251 DEB orbits at an average altitude of 327 km in the lower reaches of Low Earth Orbit, where atmospheric drag is significant and orbital lifetimes are measured in months to a few years. This is the busiest corridor in space — home to crewed spacecraft, rapid-revisit imaging satellites and the densest part of the Starlink constellation. Within ±50 km of COSMOS 2251 DEB’s average altitude, there are currently 1,074 active payloads and 35 tracked debris or rocket body fragments — notable neighbours include STARLINK-1020, STARLINK-1036, STARLINK-1043. This makes it one of the more crowded altitude bands, containing roughly 6% of all active satellites. With an inclination of 73.8°, COSMOS 2251 DEB passes over latitudes between 73.8°N and 73.8°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 1,288 active satellites in total, of which 36 share a similar altitude band with COSMOS 2251 DEB.