NAVSTAR 50 (USA 156)

NAVSTAR 50 (USA 156) is an active satellite operated by DoD/US Air Force (United States), launched on 2001-01-30 from Cape Canaveral, Florida. With over 25 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Medium Earth Orbit (MEO) at altitudes between 20,996 km and 21,014 km with an inclination of 55.2°. It travels at approximately 13,737 km/h (3.82 km/s), completing one full orbit every 12 hours 32 minutes — that’s roughly 1.92 orbits per day. It is part of the Gps Ops constellation group. Orbital Radar tracks NAVSTAR 50 (USA 156) in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

NAVSTAR 50 (USA 156) orbits at an average altitude of 21,005 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 NAVSTAR 50 (USA 156)’s average altitude, there are currently 4 active payloads and 13 tracked debris or rocket body fragments. This is a relatively sparse altitude band, containing less than 1% of all active satellites. With an inclination of 55.2°, NAVSTAR 50 (USA 156) passes over latitudes between 55.2°N and 55.2°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 12,360 active satellites in total, of which 4 share a similar altitude band with NAVSTAR 50 (USA 156).