Pronounced pee-ya-sa. Pyassa is an Urdu word literally translating to "thirst". It is also often used idiomatically meaning "longing". I think it would be a good fit for the Mars rover because the word relates to the mission in two ways. Firstly, the rover is going to search for water on Mars, which relates literally to the word thirst. Secondly, the rover is also going to collect data from the red planet to learn more about it (and see if it is habitable for humans). This means that the rover is also going to help us quench our thirst for knowledge about the unknown on our neighbor planet.