NASA's Mars rover Opportunity, well into its 9th year on Mars, will work for the next several weeks or months at a site with some of the mission's most intriguing geological features.
The site, called "Matijevic Hill," overlooks 14-mile-wide (22-kilometer-wide) Endeavour Crater. Opportunity has begun investigating the site's concentration of small spherical objects reminiscent of, but different from, the iron-rich spheres nicknamed "blueberries" at the rover's landing site nearly 22 driving miles ago (35 kilometers).
The small spheres at Matijevic Hill have different composition and internal structure. Opportunity's science team is evaluating a range of possibilities for how they formed. The spheres are up to about an eighth of an inch (3 millimeters) in diameter.