National Aeronautics and Space Administration scientists said they were examining data received from Spirit to diagnose why the rover apparently rebooted its computer.
"While we don't have an explanation yet, we do know that Spirit's batteries are charged, the solar arrays are producing energy and temperatures are well within allowable ranges. We have time to respond carefully and investigate this thoroughly," said John Callas, project manager for both Spirit and its twin rover Opportunity at NASA's Jet Propulsion Laboratory. "The rover is in a stable operations state called automode and taking care of itself. It could stay in this stable mode for some time, if necessary, while we diagnose the problem."
Spirit finished its three-month prime mission on Mars five years ago and has continued to operate through multiple mission extensions.
Notable deaths of 2014 [PHOTOS]