INMARSAT 4-F3

INMARSAT 4-F3 is an active satellite operated by INMARSAT, Ltd. (IM), launched on 2008-08-18 from Baikonur, Kazakhstan. After 18 years in orbit, it continues to be tracked by global surveillance networks. It orbits in Geostationary Orbit (GEO) at altitudes between 35,775 km and 35,799 km with an inclination of 4.3°. It travels at approximately 11,070 km/h (3.07 km/s), completing one full orbit every ~24 hours (geosynchronous) — that’s roughly 1.00 orbits per day. At geostationary altitude, there is no meaningful atmospheric drag — this object will remain in orbit indefinitely unless actively deorbited. Orbital Radar tracks INMARSAT 4-F3 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

INMARSAT 4-F3 occupies geostationary orbit at approximately 35,786 km above the equator, where its orbital period matches the Earth’s 24-hour rotation. From the ground, it appears to hover over a fixed point — ideal for broadcast television, weather monitoring and wideband communications. With an inclination of 4.3°, it traces a small figure-of-eight pattern relative to the equator rather than remaining perfectly stationary, which can indicate aging stationkeeping fuel or a deliberate inclined-orbit strategy. Within ±50 km of INMARSAT 4-F3’s average altitude, there are currently 713 active payloads and 58 tracked debris or rocket body fragments — notable neighbours include ASTRA 1N, GOES 16, TDRS 13. IM operates approximately 20 active satellites in total, of which 11 share a similar altitude band with INMARSAT 4-F3.