PTD-4

PTD-4 is an active satellite operated by ARC / Terran Orbital (United States), launched on 2024-08-16 from Vandenberg Space Force Base, United States on the Transporter-11 launch. It orbits in Low Earth Orbit (LEO) at altitudes between 487 km and 492 km with an inclination of 97.7°. It travels at approximately 27,441 km/h (7.62 km/s), completing one full orbit every 94 minutes — that’s roughly 15.26 orbits per day. Its near-polar, sun-synchronous orbit means it passes over any given point on Earth at approximately the same local solar time, ideal for consistent Earth observation lighting conditions. Its near-circular orbit (eccentricity close to zero) means it maintains a very consistent altitude throughout each revolution. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~1–3 years. Orbital Radar tracks PTD-4 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

PTD-4 orbits at an average altitude of 490 km in a sun-synchronous orbit (SSO), a specialised subset of LEO where the orbital plane precesses to maintain a constant angle relative to the Sun. This provides consistent lighting conditions on every pass — essential for Earth observation, weather monitoring and environmental science. Within ±50 km of PTD-4’s average altitude, there are currently 10,274 active payloads and 211 tracked debris or rocket body fragments — notable neighbours include STARLINK-1017, STARLINK-1039, STARLINK-1047. This makes it one of the more crowded altitude bands, containing roughly 55% of all active satellites. With an inclination of 97.7°, PTD-4 passes over latitudes between 97.7°N and 97.7°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 13,204 active satellites in total, of which 9,656 share a similar altitude band with PTD-4.