The UA's Phoenix Mars Lander went in to safe mode yesterday due to a low-power fault brought on by dropping temperatures (a high of -50F to a low of -141F) and a dust storm that reduced sunlight to the solar panels.
Engineers got the system recharging one of the batteries later, but they shut down two heaters and turned off other power users to keep some of the craft's instruments and systems alive.
[right, artist Colby Waste's rendition of the Lander as winter arrives. Credit JPL-UA]