https://www.cnet.com/news/nasa-storm-that-silenced-mars-opportunity-rover-has-finally-settled/ > The space agency measures the atmospheric opacity, known as "tau," to determine how much dust is swirling around in the Martian sky. It's at a level of 0.8, down from 10.8 on June 10, when NASA last heard from the rover. NASA uses its Mars Reconnaissance Orbiter to monitor the atmosphere from above. > Communication attempts continue. NASA has sent over 250 recovery commands to the rover, with no response. We are in a windy season for Mars, which gives some hope that winds could clean off Opportunity's solar panels and allow it to recharge and get back in touch with Earth.