NASA has declared the U.S. Mars lander Phoenix defunct, writing it off as a victim of the red planet's icy winter after numerous unsuccessful attempts to communicate with it.

NASA's Odyssey orbiter passed over the Phoenix landing site 61 times last week in a final effort to communicate but “no transmission from the lander was detected,” the space agency said. The craft landed in the planet's far northern region on May 25, 2008, and sent back signals until November of the same year when the sunlight waned.

An image taken by the orbiter last month suggested it had been damaged by a build-up of carbon dioxide ice during the long, dark winter.

“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,” he said.