Spacecraft controllers have stopped trying to use two NASA probes orbiting Mars to contact the Mars Phoenix lander, abandoning a long-shot effort to reactivate Phoenix as sunlight dwindles with the advancing winter season at its high-latitude landing site.

Phoenix last communicated with the Mars Odyssey orbiter on Nov. 2, and after one final try Nov. 29 to use Odyssey as a relay, mission managers gave up the hunt. The date marked the beginning of solar conjunction, when communications between Earth and the Mars Odyssey and Reconnaissance orbiters are difficult, and had been picked earlier to give as much time as possible to contact the lander again.

"We were hoping that another variation in weather might give us an opportunity to contact the lander again," said Phoenix Mission Manager Chris Lewicki of NASA's Jet Propulsion Laboratory, noting that a dust storm at the high-latitude landing site contributed to the original loss of contact.

As the Martian winter advances, low sunlight levels deprive the lander of the energy it needs to charge its batteries and perform the heating and other housekeeping tasks believed necessary for its survival. The unexpected dust storm just made matters worse.

Still, on the remote chance that the Phoenix hardware can survive temperatures as low as -150F, managers were planning to resume sending "transmitter on" commands to the lander when springtime returns on Mars.

Phoenix landed in the Martian arctic on May 25 for a nominal three-month mission digging for evidence of past habitability, and continued operating for two months after that. Although debate continues about the meaning of its findings, NASA says it achieved all of its science goals during its nominal operating period.

File photo of Mars Phoenix lander arm: NASA/JPL/Caltech/University of Arizona