SL-12 R/B(AUX MOTOR)

SL-12 R/B(AUX MOTOR) is a spent rocket body associated with Russia (CIS), launched on 1974-07-29 from Baikonur Cosmodrome, Kazakhstan on the Molniya-1 11F658 No. 38 launch. After more than 52 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 1,768 km and 30,773 km with an inclination of 44.8°. It travels at approximately 15,105 km/h (4.20 km/s), completing one full orbit every 9 hours 25 minutes — that’s roughly 2.55 orbits per day. Its orbital eccentricity of 0.6405 gives it a noticeably elliptical path, with significant altitude variation between perigee and apogee. Spent rocket bodies like SL-12 R/B(AUX MOTOR) are among the largest pieces of uncontrolled space debris and are priority targets for collision avoidance manoeuvres and future active debris removal efforts.

SL-12 R/B(AUX MOTOR) orbits at an average altitude of 16,271 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 SL-12 R/B(AUX MOTOR)’s average altitude, there are currently 0 active payloads and 7 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 44.8°, SL-12 R/B(AUX MOTOR) passes over latitudes between 44.8°N and 44.8°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. Russia (CIS) operates approximately 1,537 active satellites in total.