Callisto is one of the moons of Jupiter with frozen oceans just like Ganymede and Europe. Many scientists said it is the safest Jovian moon to colonize. It’s because it has the least radiation. I had read enough utopian science fiction novels that romanticizes this ocean moon. It is a very romantic place to visit. Imagine looking at the sky and you will see Jupiter and nearby moons. It is visual that you can see at the end of the trailer.