NASA ends Deep Impact comet-hunting mission after eight years

After more than eight years, NASA's comet-hunting Deep Impact mission has come to an abrupt close. The agency has stopped trying to communicate with the mission probe after losing contact on August 8th. It's not clear what went wrong, but NASA suspects that it may have lost orientation control, guaranteeing that the Deep Impact vehicle would lose power and freeze. It's going out on a good note, however. Like NASA's Mars rovers, Deep Impact easily outlasted its intended lifespan -- after successf...