PEGASUS R/B(2)

PEGASUS R/B(2) is a spent rocket body associated with United States, launched on 1998-09-23 from Esrange, Sweden on the Orbcomm FM21 launch. With over 28 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 702 km and 791 km with an inclination of 44.5°. It travels at approximately 26,941 km/h (7.48 km/s), completing one full orbit every 100 minutes — that’s roughly 14.44 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(2) 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(2) orbits at an average altitude of 747 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(2)’s average altitude, there are currently 364 active payloads and 1,935 tracked debris or rocket body fragments — notable neighbours include LANDSAT 9. With an inclination of 44.5°, PEGASUS R/B(2) passes over latitudes between 44.5°N and 44.5°S, covering the tropical and temperate zones where most of the world’s population resides. Low-to-mid inclination orbits are efficient to reach from equatorial and mid-latitude launch sites. United States operates approximately 12,413 active satellites in total, of which 147 share a similar altitude band with PEGASUS R/B(2).