DELTA 1 R/B

DELTA 1 R/B is a spent rocket body associated with United States, launched on 1964-01-21 from Cape Canaveral Space Force Station, United States on the Relay B launch. After more than 62 years in orbit, it is one of the longest-surviving objects in the space catalogue. It orbits in Medium Earth Orbit (MEO) at altitudes between 1,856 km and 7,649 km with an inclination of 46.5°. It travels at approximately 21,550 km/h (5.99 km/s), completing one full orbit every 3 hours 15 minutes — that’s roughly 7.39 orbits per day. Its orbital eccentricity of 0.2604 gives it a noticeably elliptical path, with significant altitude variation between perigee and apogee. Spent rocket bodies like DELTA 1 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.

DELTA 1 R/B orbits at an average altitude of 4,753 km in Medium Earth Orbit, the region between LEO and GEO (2,000–35,786 km). MEO’s higher altitude gives each satellite a much larger ground footprint than LEO, meaning fewer spacecraft are needed for global coverage — but signal latency is higher and radiation from the Van Allen belts is a significant design constraint. Within ±50 km of DELTA 1 R/B’s average altitude, there are currently 1 active payload and 6 tracked debris or rocket body fragments. This is a relatively sparse altitude band, containing less than 1% of all active satellites. With an inclination of 46.5°, DELTA 1 R/B passes over latitudes between 46.5°N and 46.5°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 13,206 active satellites in total.