NASA Mars Exploration Rover Status Report, January 17, 2019: Dust storm activity appears to have picked up again, with a regional storm tracking south about 124 miles (200 kilometers) to the west of Opportunity.
The storm is expected to increase in opacity (tau) at the rover site to greater than 1.5 over the next few days. No signal from Opportunity has been heard since Sol 5111 (June 10, 2018) during the historic global dust storm. Opportunity likely experienced a low-power fault, a mission clock fault and an up-loss timer fault. Since the loss of signal, the team has been listening for the rover over a broad range of times, frequencies and polarizations using the Deep Space Network (DSN) Radio Science Receiver.
They have been commanding “sweep and beeps” throughout each daily DSN pass with both right-hand and left-hand circular polarization to address a possible complexity with certain conditions within mission clock fault on the rover. They have expanded the breath of “sweep and beeps” commanding covering more times of day on Mars.
Mars is now in the seasonal period of past dust clearing events for the rover. Since loss of signal, 560 recovery commands have been radiated to the rover. [More at link]