SSU 1

SSU 1 is an active satellite operated by NRO / NRL (United States), launched on 1976-04-30 from Vandenberg Space Force Base, United States on the PARCAE 1 launch. After more than 50 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 682 km and 1,224 km with an inclination of 63.4°. It travels at approximately 26,558 km/h (7.38 km/s), completing one full orbit every 104 minutes — that’s roughly 13.83 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~100–500 years. Orbital Radar tracks SSU 1 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

SSU 1 orbits at an average altitude of 953 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 SSU 1’s average altitude, there are currently 456 active payloads and 1,312 tracked debris or rocket body fragments. With an inclination of 63.4°, SSU 1 passes over latitudes between 63.4°N and 63.4°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 13,279 active satellites in total, of which 167 share a similar altitude band with SSU 1.