INMARSAT 3-F4

INMARSAT 3-F4 is an active satellite operated by IM, launched on 1997-06-03 from Guiana Space Centre, Kourou. With over 29 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Geostationary Orbit (GEO) at altitudes between 35,960 km and 36,051 km with an inclination of 11.5°. It travels at approximately 11,041 km/h (3.07 km/s), completing one full orbit every ~24 hours (geosynchronous) — that’s roughly 0.99 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 3-F4 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

INMARSAT 3-F4 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 11.5°, 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 3-F4’s average altitude, there are currently 62 active payloads and 30 tracked debris or rocket body fragments. IM operates approximately 20 active satellites in total.