Calisto is one of the largest moons of Jupiter and is known for its heavily cratered surface, which suggests it has been around for a long time. It is made mostly of ice and rock, making it a fascinating object of study for scientists interested in the history of our solar system. Calisto's lack of geological activity means that its surface has remained relatively unchanged for billions of years. This moon is also notable for its potential to harbor a subsurface ocean, similar to other moons like Europa. The presence of water beneath its icy crust raises intriguing possibilities for the existence of life beyond Earth. Exploring Calisto could provide valuable insights into the conditions that support life in the universe.