Mike Cassidy works at Google X, the company's self-described "moonshot factory," as the leader of Project Loon. His team's goal is to deploy a global network of thousands of Wi-Fi–connected balloons that will provide affordable Internet access to everyone on the planet. Ambitious much? We asked how they plan to pull it off.

Popular Science: What was the inspiration for Project Loon?

Mike Cassidy: People have talked about high-altitude communications platforms for a long time, but they all had the same concept: a tethered balloon, or a vehicle that kept itself in one spot over the ground. We said, "We can let the balloons move with the wind." As one balloon moves away, another comes and takes its place.

PS: How did you develop the right balloon for the job?