DELTA 1 R/B(1)

DELTA 1 R/B(1) is a spent rocket body associated with United States, launched on 1977-07-14 from Cape Canaveral, Florida on the GMS 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 528 km and 1,795 km with an inclination of 29.1°. It travels at approximately 26,188 km/h (7.27 km/s), completing one full orbit every 109 minutes — that’s roughly 13.26 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 1,162 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 670 active payloads and 275 tracked debris or rocket body fragments — notable neighbours include ONEWEB-0012, ONEWEB-0010, ONEWEB-0008. With an inclination of 29.1°, DELTA 1 R/B(1) passes over latitudes between 29.1°N and 29.1°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 7 share a similar altitude band with DELTA 1 R/B(1).