Second, we cannot foresee the distant future, so we ought to develop the capability to escape from the earth. Gradually, we are learning how humans can survive for long periods in space and even travel to other planets in the future. If space exploration is halted, this valuable knowledge will never be acquired. It is true that environmental destruction is also a serious issue, but it is also true that we remain dependent on our environment if we never accept the challenge of exploring other worlds.