TACSAT 4

TACSAT 4 is an active satellite operated by Naval Research Laboratory (United States), launched on 2011-09-27 from Pacific Spaceport Complex Alaska, United States on the TacSat-4 launch. After 15 years in orbit, it continues to be tracked by global surveillance networks. It orbits in Medium Earth Orbit (MEO) at altitudes between 376 km and 12,015 km with an inclination of 62.9°. It travels at approximately 20,275 km/h (5.63 km/s), completing one full orbit every 3 hours 54 minutes — that’s roughly 6.16 orbits per day. Its orbital eccentricity of 0.4631 gives it a noticeably elliptical path, with significant altitude variation between perigee and apogee. Orbital Radar tracks TACSAT 4 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

TACSAT 4 orbits at an average altitude of 6,196 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 TACSAT 4’s average altitude, there are currently 2 active payloads and 1 tracked debris or rocket body fragment. This is a relatively sparse altitude band, containing less than 1% of all active satellites. With an inclination of 62.9°, TACSAT 4 passes over latitudes between 62.9°N and 62.9°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.