USA 77

USA 77 is an active satellite operated by NRO / NRL (United States), launched on 1991-11-08 from Vandenberg Space Force Base, United States on the SLDCOM 2/INTRUDER 2 launch. With over 35 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 379 km and 1,714 km with an inclination of 63.3°. It travels at approximately 26,390 km/h (7.33 km/s), completing one full orbit every 106 minutes — that’s roughly 13.57 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~500–1,000 years. Orbital Radar tracks USA 77 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

USA 77 orbits at an average altitude of 1,047 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 USA 77’s average altitude, there are currently 303 active payloads and 663 tracked debris or rocket body fragments — notable neighbours include ONEWEB-0041. With an inclination of 63.3°, USA 77 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 43 share a similar altitude band with USA 77.