Elon Musk, 13 years ago: A fully and rapidly reusable rocket is barely possible. SpaceX is going to try to do it. We could fail, but we're going to try to do it. “The pivotal breakthrough that's necessary, that some company has to come up with to make life multiplanetary, is a fully and rapidly reusable orbit-class rocket. This is a very difficult thing to do because we live on a planet where that is just barely possible. If gravity were a little lower, it would be easy. If it was a little higher, it would be impossible. It's just a very tough engineering problem. I wasn't sure it could be solved for a while. But then, relatively recently, probably in the last twelve months or so, I've come to the conclusion that it can be solved. And I think, SpaceX is going to try to do it. Now, we could fail. I'm not saying we're certain of success here, but we're going to try to do it. And we have a design that, on paper, doing the calculations, doing the simulations, it does work. And now, we need to make sure that those simulations and reality agree, because generally when they don't, reality wins.” National Press Club, 2011