SSD

SSD is an active satellite operated by NRL (United States), launched on 1983-02-09 from Vandenberg Space Force Base, United States on the PARCAE 5 launch. With over 43 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 666 km and 1,496 km with an inclination of 63.3°. It travels at approximately 26,329 km/h (7.31 km/s), completing one full orbit every 107 minutes — that’s roughly 13.48 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~500–1,000 years. Orbital Radar tracks SSD in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

SSD orbits at an average altitude of 1,081 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 SSD’s average altitude, there are currently 306 active payloads and 548 tracked debris or rocket body fragments — notable neighbours include ONEWEB-0041. With an inclination of 63.3°, SSD passes over latitudes between 63.3°N and 63.3°S, covering most populated land masses in both hemispheres. This mid-inclination band balances global coverage with efficient launch energy requirements. United States operates approximately 13,204 active satellites in total, of which 42 share a similar altitude band with SSD.