SCOUT X-4 R/B

SCOUT X-4 R/B is a spent rocket body associated with United States, launched on 1964-08-25 from Vandenberg Space Force Base, United States on the NASA S-48 launch. After more than 62 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 829 km and 953 km with an inclination of 79.9°. It travels at approximately 26,671 km/h (7.41 km/s), completing one full orbit every 103 minutes — that’s roughly 14.01 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~100–500 years. Spent rocket bodies like SCOUT X-4 R/B are among the largest pieces of uncontrolled space debris and are priority targets for collision avoidance manoeuvres and future active debris removal efforts.

SCOUT X-4 R/B orbits at an average altitude of 891 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 SCOUT X-4 R/B’s average altitude, there are currently 225 active payloads and 1,747 tracked debris or rocket body fragments. With an inclination of 79.9°, SCOUT X-4 R/B passes over latitudes between 79.9°N and 79.9°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 13,206 active satellites in total, of which 66 share a similar altitude band with SCOUT X-4 R/B.