I should have posted about this earlier, but real life intervened. You may have heard that there is currently a dust storm at Mars. As long as you're orbiting safely above the storm, this is merely of academic interest. But if you're roving below it, the storm is causing some rather serious problems. I spent the last week conversing with people working on all five spacecraft at Mars -- three orbiters and two rovers -- to find out what's going on with the dust storm.
Probably the most striking item I received this week was this image, which Jim Bell was kind enough to share with me. It's been even darker for Opportunity since the last of these images was taken.