AT&T and AST SpaceMobile Complete First Satellite-to-Cellular Handoff

AT&T and AST SpaceMobile completed what the two companies describe as the first successful handoff between a direct-to-device satellite network and a terrestrial cellular network. The trial ran on October 21 outside Granite Falls, Washington, and used ordinary smartphones, not modified hardware.

For operators, the result matters because handoff quality determines whether satellite coverage feels like an extension of the network or a separate service. A call that drops or stalls for seconds during the switch is a complaint ticket. A switch measured in milliseconds is invisible to the subscriber.

What did the test actually prove?

The Granite Falls trial moved a live connection between AT&T's ground-based wireless network and AST SpaceMobile's low-Earth orbit satellite constellation without dropping it. AT&T said the test built on earlier milestones: voice calls, text messages, and video calls carried through AST SpaceMobile's BlueBird satellites.

Two vendors made the radio-side plumbing work:

• Ericsson supplies AT&T's combined radio and core technology, with intelligent network automation that AT&T says optimizes handoffs between ground and satellite networks. The operator claims this cuts transition times from seconds to milliseconds.
• Nokia provided the radio access technology and mobility software powering AST SpaceMobile's space-based network, supporting the handover and service continuity.

Note the framing. The seconds-to-milliseconds claim comes from AT&T describing its vendor's automation, not from an independent measurement. It is a vendor-supported operator assertion, and it deserves that label until commercial deployments publish field data.

Why is a handoff harder than a satellite call?

A standalone satellite call is one link. A handoff is two networks agreeing, in real time, that a subscriber's connection should move between them while staying alive. The October 21 test demonstrated that an AST SpaceMobile connection and an AT&T terrestrial connection can negotiate that transfer using standard devices.

AT&T positions D2D as complementary to its terrestrial footprint rather than a replacement for it. The operator sees satellite connectivity as a tool for plugging coverage gaps in hard-to-reach parts of the United States, where tower economics do not work.

According to AT&T, the test "brings AT&T and AST SpaceMobile one step closer to commercial service."

Robert Walters, AT&T Network SVP, offered the more measured read. "The successful handoff is a significant milestone, but it's not the finish line," Walters said. "As we progress toward real-world beta services and ultimately commercial service, we're bringing together AT&T's broad and dense fiber footprint, the nation's largest terrestrial wireless network, and complementary connectivity enabled by partners such as AST SpaceMobile to create a more seamless, resilient experience."

That is a practitioner's sentence. It puts beta service ahead of commercial service on the timeline, and it names fiber, terrestrial wireless, and partner satellites as three inputs to one architecture.

What is the regulatory and investment context?

The Federal Communications Commission gave AST SpaceMobile permission earlier this year to operate its non-geostationary orbit satellite system. That approval is the regulatory gate that turns engineering trials into a licensable service path.

AT&T is one of several carriers that are active investors in AST SpaceMobile. The operator is not simply a customer; it holds a financial stake in the constellation's success, which strengthens the commercial logic behind the joint testing program.

What happens to the constellation plan?

The satellite side has its own schedule pressure. AST SpaceMobile previously outlined plans to launch between 45 and 60 of its latest-generation BlueBird satellites this year. The company has since revised that target down to 45 satellites by early 2027.

For operators counting on D2D to close coverage gaps, that revision stretches the timeline for continuous satellite coverage, since fewer satellites in orbit means longer gaps between passes over any given coverage hole. Handoff trials can succeed on a partial constellation; mass-market service needs the full one.

The path ahead, per both companies, runs through real-world beta service and then commercial launch, with the revised 45-satellite constellation target now set for early 2027.