DELTA 2 R/B

DELTA 2 R/B is a spent rocket body associated with United States, launched on 2009-12-14 from Vandenberg SFB, California on the Wide Field IR Explorer launch. After 17 years in orbit, it continues to be tracked by global surveillance networks. It orbits in Medium Earth Orbit (MEO) at altitudes between 2,135 km and 11,065 km with an inclination of 97.5°. It travels at approximately 19,957 km/h (5.54 km/s), completing one full orbit every 4 hours 5 minutes — that’s roughly 5.87 orbits per day. Its orbital eccentricity of 0.3442 gives it a noticeably elliptical path, with significant altitude variation between perigee and apogee. Spent rocket bodies like DELTA 2 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 2 R/B orbits at an average altitude of 6,600 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 2 R/B’s average altitude, there are currently 0 active payloads and 4 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 97.5°, DELTA 2 R/B passes over latitudes between 97.5°N and 97.5°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 12,413 active satellites in total.