Where in our solar system should NASA focus future missions?

I think we should know about the Europa. Because scientists already researched about Enceladus and they know there is a moon’s clouds of vapor and particles. But I think scientists don’t know about the Jupiter’s moon, Europa. There is a vapor either but there is a thick ice too. I am wondering how the ice could turned into a water. Because the Jupiter is very far from the sun, so it is really cold.¬† Scientists were saying a spacecraft will go to the Europa to launch it in 2020s. And there are other planets that having¬† ice or water in it. I think Europa has more possibility because there are many ice (19~25 kilometers ) in it and the weather is becoming hotter and hotter, so it could melt that ice too. (I think..)

Europa has an atmosphere, so it has a dense of the oxygen in it. Because of that I think later, if it has more oxygen in it, human could live in there.

I am thinking we should focus the moon or planets to replace the earth. Because know, the earth is getting hotter and hotter. Scientists are saying that we have to find planets which can replace the earth. So I am worried and think people have to find the planets which have water and other resources in it.