Kerbal Space Program

How to build a spaceship capable of delivering a human crew into space - and return this crew back? Even if we have all the necessary parts, engines, life support systems, rudders and accelerators, even if all this we have, the construction of the ship requires the correct arrangement of parts together with each other. Depending on how correct our decisions are, the ship will fly or not, it will fly right or fatally deviate from the course.