Nasa calls game over on Mars Phoenix lander

Ice proves fatal to exploration system.

Nasa has said that the Phoenix Mars lander has stopped transmission after being damaged by ice during the long Martian winter.

The Phoenix probe, which landed on Mars two years ago almost to the day, has so far failed to respond to contact attempts by the Mars Odyssey orbiter despite more than 60 fly-bys.

It is thought that ice has infiltrated the probe and rendered its computer systems inoperable.

"The Phoenix spacecraft succeeded in its investigations and exceeded its planned lifetime," said Fuk Li, manager of the Mars Exploration Program at Nasa's Jet Propulsion Laboratory in Pasadena, California.

"Although its work is finished, analysis of information from Phoenix's science activities will continue for some time to come."

Nasa's Mars Reconnaissance Orbiter shows signs of severe ice damage to the lander's solar panels that would have made it impossible for the lander to recharge. The Phoenix probe landed in the polar regions of Mars to study the composition of the surface and its elements.

"Before and after images are dramatically different," said Michael Mellon, a science team member for Phoenix and the the University of Colorado's High Resolution Imaging Science Experiment.

"The lander looks smaller, and only a portion of the difference can be explained by accumulation of dust on the lander, which makes its surfaces less distinguishable from surrounding ground."

The lander uses an IBM RAD6000 radiation-hardened RISC chip running at 33MHz and a processing speed of about 35 MIPS.

It runs off two gallium arsenide solar array panels, which have now failed.