...and there is another very good reason to launch satellites into retrograde orbits with about 98 degrees inclination: If you need your satellite to be permanently sunlit and/or if you want the satellite to fly along the terminator permanently, you need an orbit that precesses with about 1 degree per day to follow the sun, a so-called sun-synchronous orbit. But this was most likely not the case in your observation since such a satellite wouldn't fly westward. Rainer