Here's our monthly checkup with the Dawn mission, contributed by Marc Rayman, the mission's Project System Engineer. Thanks Marc! --ESL by Dr. Marc D. Rayman Dear Dawnlettantes, Now using an ion thruster that had been powered off since October, Dawn continues to make steady progress on its journey deeper into space. In this phase of the mission, each day of thrusting changes the probe's speed by 6.7 meters/second (15 miles/hour). Dawn will ....