In my head, rovers land on other worlds, spending a day or two stretching their travel-weary systems, and are then ready to rove. For the Perseverance rover, this has definitely not been the case, and for the past ninety days, Percy has stayed in a fairly small area doing a remarkable amount of babysitting a little helicopter named Ingenuity. That helicopter lacked the power or equipment to communicate back to Earth on its own, and as it is a new technology, it wasn’t entirely trusted to fly unsupervised. This meant, Percy focused on getting Ingenuity to a safe place to fly, dropped it off, and backed away to watch it flit about and record what they could on camera for all the nervous engineers and scientists back home.
Now that Ingenuity has proven itself, and the mission is finally moving on to its primary science objectives, Percy is literally getting to flex its arm as it for the first time. This arm, like arms on the rovers that came before, is outfitted with a variety of tools and instruments, including a grinding wheel and cameras. This means Percy can rove up to a rock, grind away its surface, and look at the unweathered surface underneath. And that surface beneath is the key.
Jezero crater, where Percy landed, experiences wind and erosion from blowing sand. Sunlight and the radiation of space change the surface, and dust coats everything. To look for the specific minerals and fossils that may reveal the conditions needed for life, or that life itself. As Percy starts its exploration, it will collect rocks for later retrieval by a future mission that will bring the rocks back to earth.
NASA JPL press release