Wow. This is a long video but I guarantee this will be the only time you'll find talk of a drill being anything but boring. This video explains in quite some detail how the drill arm and drilling mechanism of the Mars Curiosity rover works. How it starts digging, how it digs, and how it saves samples for analyzation after retrieval. It all seems rather elementary, but then you remember that this is a robot very far away from earth with the constant possibility of error in which no human can intervene. So if something does go wrong, NASA has to figure out how to basically tell the robot to fix itself with whatever tools it has all by itself on the Martian surface.