TIROS 4

TIROS 4 is an active satellite operated by GSFC (United States), launched on 1962-02-08 from Cape Canaveral Space Force Station, United States. After more than 64 years in orbit, it is one of the longest-surviving objects in the space catalogue. It orbits in Low Earth Orbit (LEO) at altitudes between 681 km and 789 km with an inclination of 48.3°. It travels at approximately 26,962 km/h (7.49 km/s), completing one full orbit every 100 minutes — that’s roughly 14.47 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~25–100 years. Orbital Radar tracks TIROS 4 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

TIROS 4 orbits at an average altitude of 735 km in the mid-LEO band, where atmospheric drag is minimal but radiation exposure remains manageable. Objects at this altitude persist for decades to centuries, making debris mitigation critical. This regime is popular for remote sensing constellations and scientific instruments that need stable, long-duration orbits. Within ±50 km of TIROS 4’s average altitude, there are currently 402 active payloads and 2,037 tracked debris or rocket body fragments — notable neighbours include TERRA, AQUA, ONEWEB-0179. With an inclination of 48.3°, TIROS 4 passes over latitudes between 48.3°N and 48.3°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 13,279 active satellites in total, of which 168 share a similar altitude band with TIROS 4.