MMS 4

MMS 4 is an active satellite operated by National Aeronautics and Space Administration (NASA) (United States), launched on 2015-03-13 from Cape Canaveral, Florida. After 11 years in orbit, it continues to be tracked by global surveillance networks. It orbits in Highly Elliptical Orbit (HEO) at altitudes between 10,041 km and 172,971 km with an inclination of 72.2°. It travels at approximately 7,265 km/h (2.02 km/s), completing one full orbit every 84.7 hours — that’s roughly 0.28 orbits per day. Its orbital eccentricity of 0.8323 gives it a noticeably elliptical path, with significant altitude variation between perigee and apogee. At geostationary altitude, there is no meaningful atmospheric drag — this object will remain in orbit indefinitely unless actively deorbited. Orbital Radar tracks MMS 4 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

MMS 4 follows a Highly Elliptical Orbit, sweeping between 10,041 km (perigee) and 172,971 km (apogee). It spends most of its 84.7 hours orbital period near apogee, effectively loitering over a region of interest before rapidly sweeping through perigee — a profile used for high-latitude communications (Molniya orbits), early-warning systems and magnetospheric science. Within ±50 km of MMS 4’s average altitude, there are currently 4 active payloads and 0 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 72.2°, MMS 4 passes over latitudes between 72.2°N and 72.2°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 12,339 active satellites in total, of which 4 share a similar altitude band with MMS 4.