I am Lisa Grossman, space writer for Science News. NASA's Opportunity rover's Mars mission (which I briefly worked on) is officially done. AMA!
Opportunity was supposed to last only 90 Martian days. It roved for more than 5,000 Martian days, completed the first Mars marathon, found evidence of liquid water over and over again, and changed how robots explore Mars. My first research project was a soil composition study using Opportunity data, 13ish years ago. I'll be here from about 3:30 to 5 Eastern time today to answer your questions.
Edit: I'm signing off for now, but thanks for all the questions!