AST SpaceMobile has announced plans to build between 40 and 50 satellites for a joint venture with Japanese technology company Rakuten, aimed at establishing a domestic direct-to-device satellite communications network. The partnership, announced in Tampa, Florida, is underpinned by Japanese government subsidies of up to 148 billion yen, roughly $1 billion, with a development deadline set for March 2029.
Direct-to-device, or D2D, is a satellite communications architecture in which satellites transmit radio signals directly to standard consumer devices such as smartphones and tablets, without the need for specialized satellite terminals or ground-based cellular infrastructure. The technology is designed to extend voice, text, and data connectivity to regions where traditional cell tower coverage is absent or unreliable, including rural mountain areas, maritime zones, and disaster-affected regions. Unlike conventional satellite phone services that require dedicated hardware, D2D leverages the cellular radio hardware already present in consumer devices, making the service accessible to the general public without additional equipment purchases.
Under the joint venture structure, AST SpaceMobile will be responsible for the design, manufacture, and deployment of the satellite constellation, while Rakuten brings its domestic telecommunications expertise and distribution channels in the Japanese market. The 40-to-50 satellite figure represents a constellation sized to provide the coverage density and revisit rates necessary for continuous service across Japan's archipelago, which spans approximately 3,700 kilometers from north to south. The satellites would operate in low Earth orbit, a regime that offers lower signal latency compared to geostationary satellites, at the cost of requiring a larger number of spacecraft to maintain continuous coverage.
The Japanese government's financial commitment is notable in scale. At up to 148 billion yen, the subsidy represents one of the larger national investments in satellite communications infrastructure in recent years. The March 2029 deadline provides the joint venture with approximately three years from the announcement to complete development, testing, and initial deployment. For context, AST SpaceMobile's own global BlueBird constellation, which the company has been developing since 2022, currently operates with a small number of demonstration satellites and a planned constellation of several dozen spacecraft. The Japanese venture would represent a significant scaling of the company's manufacturing and launch cadence.
Rakuten, founded in 1997 and best known internationally for its e-commerce platform, has been developing a terrestrial 5G mobile network in Japan under the brand Rakuten Mobile since 2020. The company's entry into satellite-based D2D communications extends its portfolio beyond ground-based infrastructure and positions it as a full-spectrum connectivity provider in the Japanese market, a country where approximately 30 percent of the land area consists of mountainous or otherwise difficult-to-cover terrain.
The broader D2D satellite market is in a period of rapid expansion. Several companies, including AST SpaceMobile, Starlink's parent SpaceX, and Huawei, are pursuing variants of the technology. Japan's decision to fund a domestic D2D network through a public-private partnership reflects a wider trend among governments seeking to reduce dependence on foreign satellite operators for critical communications resilience. The March 2029 timeline, if met, would place the Japanese network among the first domestically operated D2D constellations to reach commercial service.
For the aerospace industry, the contract underscores the growing commercial viability of satellite manufacturing at the 40-to-50 unit scale, a volume that sits between the small demonstration constellations of the early 2020s and the thousands of satellites in mega-constellations. It also signals that national governments are increasingly willing to subsidize satellite infrastructure as a matter of strategic communications policy, a development that may accelerate D2D adoption across other markets.