APEX R/B

APEX R/B is a spent rocket body associated with United States, launched on 1994-08-03 from Vandenberg Space Force Base, United States on the APEX launch. With over 32 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 334 km and 1,217 km with an inclination of 69.9°. It travels at approximately 26,886 km/h (7.47 km/s), completing one full orbit every 100 minutes — that’s roughly 14.35 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~25–100 years. Spent rocket bodies like APEX 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.

APEX R/B orbits at an average altitude of 776 km in the mid-LEO band, where atmospheric drag is minimal but radiation exposure remains manageable. Objects at this altitude persist for decades to centuries, making debris mitigation critical. This regime is popular for remote sensing constellations and scientific instruments that need stable, long-duration orbits. Within ±50 km of APEX R/B’s average altitude, there are currently 440 active payloads and 2,374 tracked debris or rocket body fragments — notable neighbours include ONEWEB-0455. With an inclination of 69.9°, APEX R/B passes over latitudes between 69.9°N and 69.9°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 13,201 active satellites in total, of which 182 share a similar altitude band with APEX R/B.