Red Planet rover could emerge from slumber soon Spaceflight Now

NASA officials say the best chance to hear from the napping Spirit rover again will be in September or October, but the timing of the robot’s revival from winter hibernation is an engineering guessing game. Spirit was forced to sleep by the cold winter in the Martian southern hemisphere, where low sun angles were not sufficient to power the rover through solar panels.
The stranded rover last communicated with Earth on March 22. Spirit has been stuck in a sand pit known as Troy since April 2009, leaving the rover tilted away from the sun and limiting its ability to produce electricity.
The winter solstice at Spirit’s location was May 13, and conditions should now be improving. But the rover’s batteries likely won’t be collecting enough sunlight to begin communicating again until September or October.