 that won't be cleared up until a little bit later when people actually see that rockets do work and can fly. One of the issues was that there's no air in space. So what's going to actually oxidize your fuel, right? And it turns out you can carry oxidizer with you and burn it in space. And then the other thing is there's no air for lift. So that's how an airplane flies. So how is a rocket going to fly? Well, it turns out that...