NASA's Phoenix Lander has ended it's mission on Mars and shut down. After 5 months of operation, the approach of Martian winter means that the robot's solar panels no longer generate enough light for the robot to operate. During its mission the robot lander dug, scooped, baked, sniffed and tasted the Red Planet's soil, verified the presence of water-ice in the Martian subsurface and snapped more than 25,000 pictures using its cameras and atomic force microscope. Although programmed to revive in spring, Phoenix is very unlikely to survive the winter since it's electronics will glassify, effectively becoming brittle and cracking, below -125 C.
For more information have a look at the post over at robots.net and for the robot space geeks among us much more details on space.com.