A satellite passing 550 kilometers above the Amazon rainforest and a phone sitting in a concrete stairwell in Chicago would, until recently, have had little to say to each other. That gap is what SpaceX is now trying to close permanently. The company has bought a batch of low-band spectrum licenses, the kind of airwaves that have long let terrestrial carriers push signal through brick, steel, and forest canopy alike. SpaceX says the purchase will let its Starlink Mobile service become a "major" carrier in the United States, standing alongside T-Mobile, AT&T, and Verizon rather than simply supplementing them.

The specifics matter here. The licenses include as much as 14 megahertz of paired spectrum in the 800 MHz band, a frequency range prized precisely because it travels further and penetrates walls more reliably than the higher frequencies typically used for fast urban data. This follows an earlier acquisition of 2GHz spectrum from EchoStar, made as SpaceX built out its direct-to-device ambitions. Pending approval from the Federal Communications Commission, SpaceX intends to merge this terrestrial spectrum with its satellite constellation into what it calls a single network, one that would not force a phone to switch awkwardly between "signal" and "no signal" depending on whether a person steps indoors.

That ambition rests on hardware still being deployed. The FCC has cleared SpaceX to launch 15,000 second-generation Starlink Mobile satellites, which the company claims will carry over 100 times the bandwidth of its current fleet. Combined with ground-based spectrum, this would let a single provider offer coverage in places where cell towers have never reached: mountain roads in Peru, fishing boats off Indonesia, the dead zones familiar to rural drivers everywhere. "With this new low-band spectrum and our Gen2 constellation, Starlink Mobile can now become the first network operator to deploy both satellite and terrestrial spectrum," the company said.