Elon Musk has taken his first step toward building a global broadband network in space.

Flying high: SpaceX successfully launched two test satellites—called Tintin A and Tintin B—into orbit. Musk says that they’re “deployed and communicating to Earth stations” and will attempt to say “Hello, world” as they pass over SpaceX HQ today.

Internet from space: The satellites pave the way for an entire constellation, known as Starlink, that could provide worldwide internet connections. Musk claims that it could rival fiber broadband, with low latency and speeds of up to a gigabit per second.

But: There’s a long way to go. The initial constellation requires 4,425 satellites in orbit, to be gradually launched over five years and reach full capacity by 2024. Another 7,500 satellites will—at some point—add additional capacity. Meanwhile, other firms, like Facebook and Google, are developing their own competing aerial internet services, too.