USA 31

USA 31 is an active satellite operated by NRO / SAFSP (United States), launched on 1988-09-02 from Cape Canaveral Space Force Station, United States on the VORTEX 5 launch. With over 38 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Medium Earth Orbit (MEO) at altitudes between 750 km and 39,592 km with an inclination of 27.6°. It travels at approximately 13,951 km/h (3.88 km/s), completing one full orbit every 11 hours 58 minutes — that’s roughly 2.01 orbits per day. Its orbital eccentricity of 0.7317 gives it a noticeably elliptical path, with significant altitude variation between perigee and apogee. Orbital Radar tracks USA 31 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

USA 31 orbits at an average altitude of 20,171 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 USA 31’s average altitude, there are currently 105 active payloads and 12 tracked debris or rocket body fragments. With an inclination of 27.6°, USA 31 passes over latitudes between 27.6°N and 27.6°S, covering the tropical and temperate zones where most of the world’s population resides. Low-to-mid inclination orbits are efficient to reach from equatorial and mid-latitude launch sites. United States operates approximately 13,340 active satellites in total, of which 44 share a similar altitude band with USA 31.