While Mars rover Curiosity might be getting all the attention these days, Mars rover Opportunity is still active during it’s ninth year on Mars. Starting this week, Opportunity will spend weeks or months investigating the unique geological feature of a site NASA has named “Matijevic Hill.”

The Opportunity rover will be investigating the hill’s small spherical objects that are similar to the iron-rich spheres researchers have nicknamed “blueberries.” The spheres on Matijevic Hill have a different composition than the blueberries, which were found at Opportunity’s landing site and are believed to have been formed by mineral-laden water inside rocks.

“Right now we have multiple working hypotheses, and each hypothesis makes certain predictions about things like what the spherules are made of and how they are distributed,” said Steve Squyres, Opportunity’s principal investigator. “Our job as we explore Matijevic Hill in the months ahead will be to make the observations that will let us test all the hypotheses carefully, and find the one that best fits the observations.”

The Matijevic Hill site is named after Jacob Matijevic, who led the engineering teams for he Mars Exploration rovers Spirit and Opportunity. When he passed away last month, Matijevic was chief engineer for surface operations systems for NASA’s latest Mars rover, Curiosity. The Curiosity team also honored Matijevic with a feature on Mars, naming a rock Curiosity stopped to examine after him.