WASHINGTON, Aug. 2 (UPI) -- One of NASA's two Mars rovers has not responded to controllers and may not have survived the planet's winter, U.S. scientists say.
The Spirit rover, stuck in the Martian sand since last year and unable to orient itself to collect sufficient sunlight with its solar panels to run its heaters and radio system, has not responded to signals from Earth, ABC News reported Friday.
Without the heaters, the temperature of the electronics inside the rover likely dropped to 65 degrees below zero Fahrenheit, NASA said.
Spirit and its companion rover Opportunity, still alive and working on the other side of the planet, have been exploring the Martian surface since January of 2004.
With the Martian winter over at Spirit's location, engineers sent a signal to the rover, hoping for at least a beep in response.
The answer has been nothing but silence.
"It will be the miracle from Mars if our beloved rover phones home," Doug McCuistion, director of NASA's Mars Exploration Program, said. "It's never faced this type of severe condition before -- this is unknown territory."