SECOR 4 (EGRS 4)

SECOR 4 (EGRS 4) is an active satellite operated by USA ACE / GIMRADA (United States), launched on 1965-04-03 from Vandenberg Space Force Base, United States on the SNAP-10A FS-4 launch. After more than 61 years in orbit, it is one of the longest-surviving objects in the space catalogue. It orbits in Low Earth Orbit (LEO) at altitudes between 1,268 km and 1,314 km with an inclination of 90.3°. It travels at approximately 25,966 km/h (7.21 km/s), completing one full orbit every 111 minutes — that’s roughly 12.93 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is thousands of years. Orbital Radar tracks SECOR 4 (EGRS 4) in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

SECOR 4 (EGRS 4) orbits at an average altitude of 1,291 km in the uppermost reaches of Low Earth Orbit. At this altitude, orbital decay is effectively zero without active deorbiting, and coverage footprints are significantly larger than lower LEO, though at the cost of higher latency. Within ±50 km of SECOR 4 (EGRS 4)’s average altitude, there are currently 24 active payloads and 394 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 90.3°, SECOR 4 (EGRS 4) passes over latitudes between 90.3°N and 90.3°S, providing near-global coverage including the polar regions. Polar and near-polar orbits are used for reconnaissance, weather monitoring and Earth-observation missions that need to image every part of the planet. United States operates approximately 13,279 active satellites in total, of which 9 share a similar altitude band with SECOR 4 (EGRS 4).