Elon Musk and Jeff Bezos are about to lock horns once again. Last month, the US Federal Communications Commission approved the final aspects of Project Kuiper, Amazon’s effort to deliver high-speed internet access from space. In May, the company will launch test versions of the Kuiper communications satellites in an attempt to take on SpaceX’s own venture, Starlink, and tap into a market of perhaps hundreds of millions of prospective internet users.

Other companies are hoping to do the same, and a few are already doing so, but Starlink and Amazon are the major players. “It is really a head-to-head rivalry,” says Tim Farrar, a satellite expert from the firm TMF Associates in the US. 

The rocket that will launch Amazon’s first two Kuiper satellites—the United Launch Alliance’s new Vulcan Centaur rocket—has been assembled at Cape Canaveral in Florida. Its inaugural launch is set to fly two prototype Kuiper satellites, called KuiperSat-1 and KuiperSat-2, as early as May 4. Ultimately, Amazon plans to launch a total of 3,236 full Kuiper satellites by 2029. The first of that fleet could launch in early 2024.

“They have ambitions to be disruptive across the technology sector,” says Farrar. “It’s hardly surprising that they’ve jumped in here.”

In the past few years, companies have been trying to expand access to the internet via satellite, both as commercial ventures and to supply internet to those in remote locations without otherwise easy access. Starlink, the mega-constellation of more than 3,500 satellites built by Musk’s SpaceX, is the biggest of these ventures. 

Amazon announced Project Kuiper in 2019, the same year Starlink began launching, leading Musk to tweet that Bezos, then the company’s CEO, was a “copycat.” Others are in development too, such as the UK-based OneWeb, which currently has more than 500 satellites. But Farrar says the key competition is between SpaceX and Amazon.

To take on SpaceX, last year Amazon revealed it had essentially bought all the spare rocket launch capacity in the world (although with little effect on its rival, because SpaceX launches satellites on its...