PEGASUS R/B

PEGASUS R/B is a spent rocket body associated with United States, launched on 1993-04-25 from Vandenberg SFB, California on the Alexis launch. With over 33 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 736 km and 827 km with an inclination of 69.9°. It travels at approximately 26,875 km/h (7.47 km/s), completing one full orbit every 100 minutes — that’s roughly 14.33 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~25–100 years. Spent rocket bodies like PEGASUS 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.

PEGASUS R/B orbits at an average altitude of 782 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 PEGASUS R/B’s average altitude, there are currently 420 active payloads and 2,226 tracked debris or rocket body fragments — notable neighbours include NOAA 20, ONEWEB-0179, ONEWEB-0455. With an inclination of 69.9°, PEGASUS 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 12,413 active satellites in total, of which 153 share a similar altitude band with PEGASUS R/B.