NASA Mars Exploration Rover Status Report, September 4, 2018: No signal from Opportunity has been heard since Sol 5111 (June 10, 2018), though NASA has approved a strategy for listening for the rover through January of 2019.
It is expected that Opportunity has experienced a low-power fault and perhaps, a mission clock fault and then an up-loss timer fault. The science team continues to listen for the rover either during the expected fault communication windows or listening over a broader range of times using the Deep Space Network Radio Science Receiver.
The science team is also sending a command three times a week to elicit a beep if the rover happens to be awake, and will soon be expanding the commanding to include “sweep and beeps” to address a possible complexity with certain conditions within the mission clock fault. These will continue through January of 2019.
The dust storm on Mars continues its decay with atmospheric opacity (tau) over the rover site continuing to decrease. Once the tau has fallen below an estimated measurement of 1.5 twice – with one week apart between measurements – a period of 45 days will begin representing the best time for us to hear from the rover.
This also represents the best time to attempt active commanding during a specific mission clock fault condition. Back during the attempted recovery of the Spirit rover, a technical issue required the team to actively command the rover to communicate. Opportunity has no such issue; if we hear from it, it will likely be from listening passively as we have been, and as we will continue to do through January.
We will also actively attempt to command the rover to communicate during the 45-day listening period to cover the clock fault condition. After that, we will report to NASA on our efforts… [More at link]