As of February 28, 2013 Dr. Marc D. Rayman updated the Dawn Mission | Dawn Journal and answers this question. The update is quite informative with the latest in Dawn’s travels, how well its doing with the ion propulsion system to help speed it along; and also comes with analogies to help you understand the infinitesimal distances Dawn is traveling since its launch into space September of 2007.
On an 8 year space exploration journey, Dawn’s main mission is to visit Vesta and Ceres. Objective: A mission for exploration of main belt asteroids Vesta and Ceres, to acquire data to help answer questions regarding the formation and evolution of the solar system.
Back in 2006, the Dawn Project fabricated a chip to be carried on the spacecraft. The chip was imprinted with the name of each person who wanted to have a part in Dawn’s adventure. I was fortunate enough to meet the deadline and enlisted my father’s name (in his memory) and received an “Asteroid Belt Certificate” with his name on it. “Congratulations “GDR” (abbreviated here for privacy)! Your name is traveling aboard the Dawn spacecraft on its mission to the Asteroid Belt.” Today, almost 6 years later, the Dawn member chip is approximately 212 million miles from earth.
“Radio signals, traveling at the universal limit of the speed of light, take 38 minutes to make the round trip.”
Please take a moment to enlighten yourself on this wild and educational journey.