TRANSIT 4A

TRANSIT 4A is an active satellite operated by USN BuWeps (United States), launched on 1961-06-29 from Cape Canaveral Space Force Station, United States. After more than 65 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 865 km and 976 km with an inclination of 66.8°. It travels at approximately 26,617 km/h (7.39 km/s), completing one full orbit every 103 minutes — that’s roughly 13.92 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~100–500 years. Orbital Radar tracks TRANSIT 4A in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

TRANSIT 4A orbits at an average altitude of 921 km in the upper LEO band, where atmospheric drag is negligible and objects can persist for centuries to millennia. This altitude is used by broadband constellations like OneWeb and by scientific missions requiring stable orbits far from the densest debris bands. Within ±50 km of TRANSIT 4A’s average altitude, there are currently 339 active payloads and 1,406 tracked debris or rocket body fragments. With an inclination of 66.8°, TRANSIT 4A passes over latitudes between 66.8°N and 66.8°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 13,276 active satellites in total, of which 165 share a similar altitude band with TRANSIT 4A.