The BBC report that NASA have declared the Phoenix lander to be silent, presumed dead, having lasted two months longer than its expected three month operating period.
Having not heard from it since the 2nd of November, NASA are scaling down operations, while listening in just in case it has more surprises in store. With no power to supply warmth, the cold of a Northern Martian winter will break the solar panels and electronics.
Phoenix was a resurrection of the Mars Polar Lander, the original of which was lost near the South Pole.
The other NASA stalwarts, Opportunity and Spirit, are still going in the relatively balmy equatorial region.