AST SpaceMobile, a company specializing in space-based cellular capabilities, announced a groundbreaking achievement this week. It successfully transmitted a 4G LTE signal from its BlueWalker 3 satellite to off-the-shelf smartphones in Hawaii using AT&T’s cellular network. With repeated download speeds exceeding 10 Mbps during testing, the signal was fast enough for normal browsing, messaging, and video streaming. This feat is remarkable because cell phones typically connect to ground-based cell towers rather than satellites, making it challenging to maintain cell service in remote areas or on boats at sea. However, AST SpaceMobile’s satellite technology opens up the possibility of expanding coverage to almost any location on the planet, eliminating concerns about signal dead zones.

Abel Avellan, Chairman and CEO of AST SpaceMobile, explained the significance of their space-based cellular capabilities, stating, “In addition to supporting basic voice and text that we expect from phones, it would also enable users to browse the internet, download files, use messaging apps, or stream video.”

A major challenge with cell coverage is the limited range of cell towers. The 5G networking standard, for example, employs different spectrum bands to provide various cellular services. Low-band 5G has the greatest range but the lowest speeds, while mid-band strikes a balance between speed and range. High-band or millimeter wave offers incredibly fast speeds but only over short distances. Therefore, as range increases, speed decreases.

In urban and suburban areas, the distance to the cell tower is typically within a mile or two, while in rural areas, towers can theoretically cover up to 45 miles. However, various factors affect the connection, and the range is often shorter. These limitations pose a significant challenge when trying to provide high-speed cellular broadband across a vast area like the United States using ground-based towers. This is where the concept of space-based broadband becomes crucial.

While satellite phones and satellite broadband services requiring a small dish exist, there has yet to be a satellite broadband service that can reach regular smartphones, which would enable cell companies to provide nationwide coverage. AST SpaceMobile aims to fill this gap by building such a service.

According to Chris Sambar, head of AT&T, achieving double-digit download speeds during satellite-to-smartphone testing brings them closer to ensuring connectivity for people across the United States, regardless of their location. The proposed technology would allow smartphones to connect to ground-based cell towers in most areas but switch to a satellite in low-Earth orbit when traversing remote regions like the Sierra Nevadas or Rocky Mountains. AST SpaceMobile has already established agreements with over 35 global cellular providers.

The successful transmission of a 4G LTE signal from the BlueWalker 3 satellite in low-Earth orbit to cellphones in Hawaii over AT&T’s network marks a significant milestone for AST SpaceMobile. The BlueWalker 3 satellite, described as the largest-ever commercial communications array deployed in low-Earth orbit, spans 693 square feet. AST SpaceMobile’s next goal is to achieve 5G speeds.

Satellite broadband does come with its own challenges. Concerns about the increasing number of satellites in space have been raised. Additionally, while space-based communication is effective for downloads and calls, upload speeds and latency can be lower compared to ground-based towers. The round trip time to space introduces a delay. Nonetheless, this recent achievement suggests that the vision of driving across America without losing phone signal may be within reach in the future.

By Impact Lab