KEPLER-21

KEPLER-21 is an active satellite operated by Kepler Communications (Canada), launched on 2023-04-15 from Vandenberg SFB, California. It orbits in Low Earth Orbit (LEO) at altitudes between 268 km and 274 km with an inclination of 97.3°. It travels at approximately 27,888 km/h (7.75 km/s), completing one full orbit every 90 minutes — that’s roughly 16.02 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 weeks to months. Orbital Radar tracks KEPLER-21 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

KEPLER-21 orbits at an average altitude of 271 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 KEPLER-21’s average altitude, there are currently 162 active payloads and 6 tracked debris or rocket body fragments — notable neighbours include STARLINK-1151, STARLINK-1143, STARLINK-1280. With an inclination of 97.3°, KEPLER-21 passes over latitudes between 97.3°N and 97.3°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. Canada operates approximately 67 active satellites in total, of which 2 share a similar altitude band with KEPLER-21.