Dawn's Ion Light

I got a mission status report from JPL on the Dawn mission, which launched successfully back on September 27. The report said that JPL engineers had tested the spacecraft's ion engine for 27 hours this past weekend, a drop in the bucket compared to the 50,000 hours they are expected to thrust over the life of the mission. I wrote about Dawn back in July when it was originally expected to launch, and I simulated some parts of the mission in Orbiter using the excellent add-on package by Brian Jones. The Orbiter picture here shows the ion engine firing in close proximity to Ceres, which Dawn will not actually reach for a few years (2015, after Vesta in 2011).