H-2 R/B

H-2 R/B is a spent rocket body associated with Japan, launched on 1996-08-17 from TNSTA on the ADEOS launch. With over 30 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 858 km and 1,305 km with an inclination of 98.8°. It travels at approximately 26,328 km/h (7.31 km/s), completing one full orbit every 107 minutes — that’s roughly 13.47 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~500–1,000 years. Spent rocket bodies like H-2 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.

H-2 R/B orbits at an average altitude of 1,082 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 H-2 R/B’s average altitude, there are currently 184 active payloads and 400 tracked debris or rocket body fragments — notable neighbours include ONEWEB-0041. With an inclination of 98.8°, H-2 R/B passes over latitudes between 98.8°N and 98.8°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. Japan operates approximately 190 active satellites in total, of which 3 share a similar altitude band with H-2 R/B.