At X, we spend most of our time breaking things and working to discover that we’re wrong. We run hard and fast at the biggest problems so we can learn and adapt quickly. The world, whether through realities of physics or nature or public opinion, will consistently tell us what’s broken in our ideas. And this helps us to go faster and take on more moonshot ideas precisely because we’re willing to move on quickly from ideas that aren’t panning out.

Astro Teller talks about moonshots and sometimes killing them.