Going straight up is hard. It takes a lot of energy. For those of us who enjoy hiking, cycling or running, hills are the bane of our existence. The hills sap us of our strength and speed, and they require more effort than we often want to expend.
Rockets are the ultimate definition of vertical ascent: They go up, fast. They need lots of raw power, and they need it immediately. Interestingly, though, the modern incarnation of reusable rocketry has come back to the same basic fuel as the human body uses: hydrocarbons. Granted, SpaceX and Blue Origin’s massive rockets are not using sugar, carbs or fats, but they are using the simplest hydrocarbon, methane: a single carbon atom with four hydrogen atoms around it, CH₄.
