The Phoenix Mars Lander went silent last November, after successfully completing its mission and returning unprecedented primary science phase and returning science data to Earth, NASA stated.

NASA said the lander operated two months longer than its planned three-month mission during summer on northern Mars before the seasonal ebb of sunshine ended its work. Since then, Phoenix’s landing site has gone through autumn, winter and part of spring. The lander’s hardware was not designed to survive the temperature extremes and ice-coating load of an arctic Martian winter, NASA said.

Phoenix landed on Mars on May 25, 2008, and operated successfully about two months longer than its planned three-month mission near the Martian north polar region.

Martian winter is also playing a part in a possible death scenario of another NASA Mars spacecraft, the Mars rover Spirit. NASA recently celebrated Spirit’s sixth anniversary exploring the red planet. But the space agency is also looking for a way to keep the machine, which is mired in a sand trap, alive to see a seventh year.