“So it’s really quite a difficult technical challenge.”

BOCA CHICA, Texas—SpaceX and T-Mobile announced an ambitious plan on Thursday evening to provide ubiquitous connectivity from space to anyone with a cell phone.

The project would pair SpaceX’s Starlink satellite technology with the second-largest wireless carrier in the United States, T-Mobile US, and its mid-band spectrum, mobile network, and large customer base.

Delivering space-to-ground Internet to mobile phones will require SpaceX to finalize development of its second generation of Starlink satellites. These will be significantly larger than the current ones, which have a mass of about 295 kg. SpaceX founder and chief engineer Elon Musk said the project could enter “beta service” before the end of 2023.

During a live event at SpaceX’s Starbase facility in South Texas, where the company is building and testing its next-generation Starship rocket, Musk appeared alongside T-Mobile US chief executive Mike Sievert. The event had something of a rocket concert flair, with a smoke machine, fireworks, and plenty of people mingling around the stage in black T-shirts. Only, these shirts bore magenta T-Mobile and white SpaceX logos, and three Starship prototypes loomed in the background.

The companies are proposing to deliver a service dreamed about since the advent of mobile telephones—no dead zones. “Our vision is, if you have a clear view of the sky, you’re connected,” Sievert said.

How this would work

Presently, a user of SpaceX’s Starlink service needs to have a dish-shaped terminal that can pull down broadband Internet from one of the 2,800 Starlink satellites in low Earth orbit. The existing satellites are just not powerful enough to connect to much smaller mobile phones, as the signal is too weak.

The solution to this problem is using a much more powerful phased array antenna on the second version, or V2, of the Starlink satellites. Musk said the body of these satellites would be about 7 meters long, and the antenna would fold out to be about 5 meters on a side, or “roughly 25 square meters.” As the satellite passes overhead, this antenna will send and receive data along a focused beam passing across the planet’s surface.