Basically Uchuu Kyoudai is an anime that depics the true life in the outside world, in the anime itself, there are many characters that are not able to fulfill their dreams, and even if they did, they were not able to go to the moon as fast as they wanted to. This thus depics the cruel life in the outside world, where life does not go as smoothly as you hope it will, however, this anime tells you that as long you put your heart and soul into it, you will definitely get what you want sooner or later, its just a matter of time