CALSPHERE 4(A)

CALSPHERE 4(A) is an active satellite operated by United States, launched on 1965-08-13 from Vandenberg Space Force Base, United States on the Dodecapole 2 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 1,072 km and 1,175 km with an inclination of 89.9°. It travels at approximately 26,254 km/h (7.29 km/s), completing one full orbit every 108 minutes — that’s roughly 13.36 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~500–1,000 years. Orbital Radar tracks CALSPHERE 4(A) in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

CALSPHERE 4(A) orbits at an average altitude of 1,124 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 CALSPHERE 4(A)’s average altitude, there are currently 283 active payloads and 451 tracked debris or rocket body fragments — notable neighbours include ONEWEB-0041, ONEWEB-0250, ONEWEB-0685. With an inclination of 89.9°, CALSPHERE 4(A) passes over latitudes between 89.9°N and 89.9°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 13,206 active satellites in total, of which 35 share a similar altitude band with CALSPHERE 4(A).