Orbits and intercalibration opportunities

TRUTHS will fly on a Pole-to-Pole non-sun-synchronous orbit, with a repeat cycle of 61 days, ensuring exact year-to-year repeatibility. The ground-track will hence precess over varying local solar times throughout the year and ensure frequent simultaneous nadir observations (SNO) with other polar orbiters as well as with geostationnary missions at their sub-satellite point.

Intercalibration of third missions will hence be possible at unprecedented accuracy by direct ray-tracing, using TRUTHS SI-traceable golden standard reference measurements. The slewing capability of the platform will also enable occasional simultaneous slanted observations to complete the intercalibration at higher viewing angles, e.g. away from the sub-sat point for Geostationnary missions and towards swath edge for Low-Earth Orbiting missions.