NASA and JPL said Monday they were formally closing down the Phoenix Mars Lander program after repeated attempts to contact the craft failed and new images from the Mars Reconnaissance Orbiter showed that it was apparently irretrievably damaged.
"We will make no further efforts to contact it," said project manager Barry Goldstein of the Jet Propulsion Laboratory in La Canada-Flintridge.
The decision was not particularly surprising because virtually no one had expected the craft to survive the long Martian winter near the planet's north pole."I was very, very skeptical," Goldstein said.
Phoenix landed on Mars on May 25, 2008, and immediately conducted a series of highly successful tasks, digging into ice and discovering that the soil in the northern plains was much more conducive to life than had been expected.
The lander had been designed for a three-month lifespan, but it lasted far longer, sending its last message on Nov. 2 of that year as the sun was sinking below the horizon. When the sun came back above the horizon in January of this year, the team began trying to contact the craft again, but without success.
The clincher came when the orbiter photographed the lander and researchers compared the image to those taken while the lander was active. The images show that the lander is smaller and darker than before, suggesting that the solar arrays that powered it have fallen off.
The arrays are warmer than the rest of the craft, Goldstein said, and they are the first place that carbon dioxide ice would accumulate. Researchers estimated that several hundred pounds of ice could have built up, cracking the arrays and causing them to break off.
"You could speculate that dust is covering the arrays and you don't see them any more, but the shadows are no longer there, which tells us that the solar arrays have fallen to the ground," he said.
Without the arrays, the craft has no power.
The JPL team is now working on the Mars Science Laboratory, which is due to launch in November 2011.