Analysis of information sources in references of the Wikipedia article "Opportunity (rover)" in English language version.
Now NASA scientists are trying a last-ditch attempt to contact the rover based on three unlikely but possible scenarios: that the rover's primary X-band radio has failed, that both the primary and secondary X-band radios have failed, or that the rover's internal clock has become offset. The team is commanding the rover to switch to its backup X-band radio and to reset its clock to counteract these possibilities.