Scanning and Trajectory
With the adjustable angle radar sensor - along with other course refinements (precession by the earth flattening) - any place on earth can be observed preferentially within 1–3 days.
For a specific point on the Earth's equator, TerraSAR X has a revisit cycle of 11 days. The revisit time decreases towards the poles, e.g. northern Europe has a revisit time of typically 3–4 days.
Read more about this topic: Terra SAR-X