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Section of Dawn’s approach trajectory

Section of Dawn’s approach trajectory
Section of Dawn’s approach trajectory We are looking down on the north pole of Ceres. (Readers who reside in the constellation Draco will readily recognize this perspective). The sun is off the figure far to the left. The spacecraft flies in from the left and then is captured (enters orbit) on the way to the apex of its orbit. It gets closer to Ceres during the first part of its approach but then recedes for a while before coming in still closer at the end. When Dawn is on the right side of the figure, it sees only a crescent of Ceres, because the illumination is from the left. The trajectory is solid where Dawn is thrusting with its ion engine, which is most of the time. The labels show where it pauses to turn, point at Ceres, conduct the indicated observation, turn to point its main antenna to Earth, transmit its precious findings, turn back to the orientation needed for thrusting, and then restart the ion engine. Because RC1 and RC2 observations extend for a full Cerean day of more than nine hours, those periods are longer, both to collect data and to radio the results to Earth. Note that there are four periods on the right side of the figure between capture and OpNav 6 when Dawn pauses thrusting for telecommunications and radio navigation but does not take pictures, as explained here. NASA / JPL-Caltech