Measuring space radiation high over Ceres, Dawn revolves once every 30 days in its gravitational master's firm grip. It is only coincidental that the lowest altitude of this intermediate orbit, XMO6, is so close to height of the lowest orbit so far. (As in that figure, the spacecraft orbits counterclockwise here, and sunlight comes from the right.) At the high point of XMO7, Dawn will move at only about 120 mph (190 kph). Image credit: NASA/JPL-CaltechOf course, as Dawn orbits Ceres, Ceres turns on its axis, pirouetting beneath her admiring companion.