The Phoenix robot, left by NASA on the Martian Pole last Martian Fall, has been hidden by seasonal darkness and is presumably covered with ice. The explorer had performed very well during its mission, and it is not expected to have survived the winter.
However, if, when sunshine warms its frosty panels, the science robot develops a positive energy balance, its circuits still work, Phoenix will alternately use its two radios and its two antennas to send out a signal. In the mean time, the Odyssey, which is a NASA flying robot circling the planet, will try to pick up this signal and re-establish communications.
Essentially, Odyssey will ask Phoenix how it’s doing, and Phoenix will provide information on its condition. Depending on the results of any such contact (which is not likely to happen at all) NASA may press Phoenix into extended service.
Here’s a picture of the Phoenix lander taken on Jan. 6, 2010 by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter: