Space is a desert unlike anything encountered on Earth. The human body is not configured to be able to survive in the cold, dark vacuum of this unearthly realm; creatures of this planet were never meant to go into space. We can only go there if we make machines to take and provide us with all the necessary things our bodies need to stay alive.
To survive and thrive in this machine-dominated environment, we need to know how those machines work and how to maintain them. This takes a strong background in technical subjects—mathematics, science, and engineering. These subjects are interesting, and for many people, mostly fun. But they can be difficult to master.
The theoretical basis for our machines must be understood, but we must also have the practical hands-on mechanical-electrical skills needed to keep them running and fix them when they break down. Crew members who work on their cars and do their own home repairs are well prepared for what is required when they venture into space. When something breaks on a spacecraft, you have to get your hands dirty.
If you want to fly into space and be a part of this new frontier, you must study and absorb the fundamentals of these subjects, and develop the hands-on repair skills needed to keep things running smoothly. As in any wilderness, be it on Earth or in space, if you should find yourself without the necessary technical knowledge and skills, you will be at the mercy of the elements. You will have compromised your ability to complete the mission, and perhaps even decreased your chances of survival.