DELTA 1 R/B(1)

DELTA 1 R/B(1) is a spent rocket body associated with United States, launched on 1977-12-15 from Cape Canaveral, Florida on the CS launch. With over 49 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 474 km and 1,687 km with an inclination of 28.7°. It travels at approximately 26,330 km/h (7.31 km/s), completing one full orbit every 107 minutes — that’s roughly 13.48 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~500–1,000 years. Spent rocket bodies like DELTA 1 R/B(1) are among the largest pieces of uncontrolled space debris and are priority targets for collision avoidance manoeuvres and future active debris removal efforts.

DELTA 1 R/B(1) orbits at an average altitude of 1,081 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 DELTA 1 R/B(1)’s average altitude, there are currently 184 active payloads and 403 tracked debris or rocket body fragments — notable neighbours include ONEWEB-0041. With an inclination of 28.7°, DELTA 1 R/B(1) passes over latitudes between 28.7°N and 28.7°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 13 share a similar altitude band with DELTA 1 R/B(1).