Parts of the uυ-coverage of 8.9-h duration for 30, 400, and 1000 km separations of the orbits at 230 GHz; first, 81st, and 161st snapshots are shown (from top to bottom). Blue points correspond to the most separate pair of satellites; red points correspond to the pair of the innermost and the middle satellites; green points correspond to the pair of the middle and the outermost satellites.