“Phoenix is on a three month mission.” Of course, the last two three month mission to Mars are still working and returning data so, we’ll see how long this one lasts. Of course, since Phoenix is near Mar’s North Pole and is solar powered, it will be out of commission when the sun goes down for a few months. But, when the sun comes up again, hopefully Phoenix will be able to re-power itself.
One of the scientists involved said that the lander will be covered with a meter of frozen CO2. Powering up after that might be iffy.