AST SpaceMobile, which is currently building a groundbreaking space-based cellular broadband network accessible directly by standard mobile phones, has announced the successful completion of two-way voice calls made directly to everyday unmodified smartphones using the company’s BlueWalker 3 (BW3) satellite. This is the first time anyone has ever achieved a direct voice connection from space to everyday cellular devices, the company said.

The voice calls were made from Texas to technology company Rakuten in Japan over AT&T spectrum using a Samsung Galaxy S22 smartphone, and were supported by engineers from Vodafone, Rakuten and AT&T. The calls validate the AST SpaceMobile patented system and architecture and demonstrate the power of the BW3 satellite — understood to be the largest ever commercial communications array deployed in low Earth orbit — acting as an important step to providing space-based 2G, 3G, 4G LTE and 5G cellular broadband globally.

“Achieving what many once considered impossible, we have reached the most significant milestone to date in our quest to deliver global cellular broadband from space,” said Abel Avellan, Chairman and CEO of AST SpaceMobile. “While we take a moment to celebrate this tremendous accomplishment, we remain focused on the path ahead and pivotal next steps that get us closer to our goal of transforming the way the world connects.”

In addition to test calls, AST SpaceMobile engineers conducted initial compatibility tests on a variety of smartphones and devices. The phones successfully exchanged SIM and network information directly to BW3 — crucial for delivering broadband connectivity from space to any phone or device. Additional testing and measurements on the smartphone uplink and downlink signal strength confirm the ability to support cellular broadband speeds and 4G LTE/5G waveforms.

“It was a unique thrill and honour to have the Rakuten team talk with Abel in a world-first direct-to-satellite experience,” said Mickey Mikitani, Chairman and CEO of Rakuten. “Congratulations to AST SpaceMobile and all of its strategic collaborators on this groundbreaking event. As technological advancements like space connectivity become possible with pioneers like AST SpaceMobile, Rakuten will also progress even further along the road to democratising connectivity for all.”

Image caption: 3D-rendered illustration of AST SpaceMobile’s BlueWalker 3 test satellite, currently in low Earth orbit.