NAVSTAR 15 (USA 42)

NAVSTAR 15 (USA 42) is an active satellite operated by U.S. Space Force (United States), launched on 1989-08-18 from Cape Canaveral, Florida. With over 37 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Medium Earth Orbit (MEO) at altitudes between 21,508 km and 21,576 km with an inclination of 55.0°. It travels at approximately 13,604 km/h (3.78 km/s), completing one full orbit every 12 hours 54 minutes — that’s roughly 1.86 orbits per day. It is part of the Gps Ops constellation group. Orbital Radar tracks NAVSTAR 15 (USA 42) in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

NAVSTAR 15 (USA 42) orbits at an average altitude of 21,542 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 15 (USA 42)’s average altitude, there are currently 37 active payloads and 7 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 55.0°, NAVSTAR 15 (USA 42) passes over latitudes between 55.0°N and 55.0°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 12,339 active satellites in total, of which 2 share a similar altitude band with NAVSTAR 15 (USA 42).