DELTA 1 R/B

DELTA 1 R/B is a spent rocket body associated with United States, launched on 1968-07-04 from Vandenberg Space Force Base, United States on the RAE A launch. After more than 58 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 685 km and 5,721 km with an inclination of 120.7°. It travels at approximately 23,229 km/h (6.45 km/s), completing one full orbit every 2 hours 36 minutes — that’s roughly 9.26 orbits per day. Its orbital eccentricity of 0.2630 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 3,203 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 2 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 120.7°, DELTA 1 R/B passes over latitudes between 120.7°N and 120.7°S, providing near-global coverage including the polar regions. Polar and near-polar orbits are used for reconnaissance, weather monitoring and Earth-observation missions that need to image every part of the planet. United States operates approximately 13,206 active satellites in total.