EXPLORER 29 (GEOS 1)

EXPLORER 29 (GEOS 1) is an active satellite operated by GSFC (United States), launched on 1965-11-06 from Cape Canaveral Space Force Station, United States on the GEOS A launch. After more than 61 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 1,120 km and 2,268 km with an inclination of 59.4°. It travels at approximately 25,309 km/h (7.03 km/s), completing one full orbit every 2 hours — that’s roughly 11.97 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is thousands of years. Orbital Radar tracks EXPLORER 29 (GEOS 1) in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

EXPLORER 29 (GEOS 1) orbits at an average altitude of 1,694 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 EXPLORER 29 (GEOS 1)’s average altitude, there are currently 21 active payloads and 83 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 59.4°, EXPLORER 29 (GEOS 1) passes over latitudes between 59.4°N and 59.4°S, covering most populated land masses in both hemispheres. This mid-inclination band balances global coverage with efficient launch energy requirements. United States operates approximately 13,279 active satellites in total, of which 2 share a similar altitude band with EXPLORER 29 (GEOS 1).