After nearly a year of trying to reestablish communications with the Spirit Mars rover, NASA has decided to suspend efforts. For all intent and purpose, Spirit is dead. The rover sent its last message in March of 2010, and it was hoped that as Martian summer dawned at Spirit's location, the solar cells might absorb enough energy to reawaken the plucky explorer. However, repeated attempts over several months have yielded no joy. And now, just months away from the launch of the much more ambitious "Curiosity" Mars Science Laboratory -- a golfcart-sized rover with better range and instrumentation than any previous mission -- communications satellites and Mars orbiters NASA uses to work with Spirit need to be transitioned to MSL. This makes me sad, of course: Spirit was an amazing machine. But I have to admit, that sadness is offset by the incredible accomplishments of the rover. Designed to last for three months, Spirit kept on roving for over six years. Imagine having a car, a computer, that lasted for 25 times the warranty! Or living to be 1500 years old. How much could you accomplish in that time? Spirit's made good use of its lifespan. So while I'm sad about this, I know (as I wrote when we lost communication with Spirit last year) that this robot is one of the most successful NASA missions of all time. It's hard not to anthropomorphize our work sometimes, and I think it's appropriate to be sad. But I'm also very happy that Spirit could do what it did. It was a triumph of human engineering, human cleverness, and the very human need to explore what's around the next corner... even when that corner is a hundred million kilometers away.