The contract is for the development of a network known as the Space Data Network Backbone.

WASHINGTON — The U.S. Space Force awarded SpaceX a $2.29 billion contract to build a network of low Earth orbit satellites intended to function as a military internet in space. According to a news release, the contract is for the development of a network known as the Space Data Network Backbone. Previously known as MILNET, these will be optically interconnected satellites that would transport military data through space rather than relying primarily on terrestrial relay networks or ground stations. The award was issued by the Space Force’s Portfolio Acquisition Executive for Space-Based Sensing and Targeting, a newly established organization overseeing the broader Space Data Network, or SDN, effort. The SDN backbone will serve as the “backhaul” layer of the architecture. In telecommunications terms, backhaul refers to the high-capacity movement of data between distributed networks. The satellites would relay large volumes of military data among spacecraft, sensors, command systems and weapons platforms. The system is intended to form the core transport layer for future military operations in space, enabling near-real-time transmission of targeting and sensor data across global networks. SpaceX will build the system using its Starshield satellites, but the constellation will be operated by the Space Force. Starshield is a government-focused variant of the company’s commercial Starlink broadband constellation. According to the company, Starshield leverages Starlink technology to provide secure satellite networks designed for national security missions. Elon Musk has described Starshield as a “separate network that is operated by the U.S. government.” The Space Force said the SDN backbone will be integrated with the Space Development Agency’s Transport Layer constellation, a separate low Earth orbit mesh network intended to provide military communications and data relay services. SDA has procured more than 300 Transport Layer satellites through its Tranche 1 and Tranche 2 contracts with multiple vendors. But the Pentagon restructured the effort before initiating Tranche 3 procurements, shifting emphasis toward the Space Data Network. The move generated concerns because it concentrates a major portion of future satellite procurement under SpaceX, whereas SDA’s earlier Transport Layer acquisitions were distributed across several companies. The Space Force said additional vendors are expected to participate in the broader SDN architecture over time. “Current acquisition efforts between SDN Backbone and SDA’s Transport layer come together to evolve capabilities and build out the LEO portions of the SDN hybrid mesh data network,” the Space Systems Command said in a statement. “Together, these systems will form a unified and open architecture to provide critical data transport.” The contract was awarded through an Other Transaction Authority agreement, or OTA, a contracting mechanism often used for prototype and rapid-development programs. The Space Force said the agreement requires delivery of a fully operational prototype capability by the end of 2027. Col. Ryan Frazier, acting portfolio acquisition executive for Space-Based Sensing and Targeting, said the SDN backbone is intended to support continuous global military connectivity. The broader SDN architecture “acts as a core communications layer for the U.S. Space Force, ensuring our sensors and shooters are connected continuously, globally and securely,” Frazier said. The Space Force also has established an “SDN consortium” intended to coordinate interoperability and standards among participating vendors. ‘Sensor to shooter’ connectivity The architecture has become increasingly linked to the Pentagon’s Golden Dome missile defense initiative, a proposed layered defense system intended to track and shoot down advanced missile threats using a combination of space-based sensors, communications networks and interceptor systems. Military officials view the SDN as a foundational component because it would allow missile-tracking satellites to rapidly transmit targeting data through orbital relay networks to command systems or interceptors with minimal delay. For example, a satellite detecting a missile launch could pass tracking information through the SDN mesh network directly to missile defense systems or combat units, creating what military planners describe as “sensor-to-shooter” connectivity. Gen. Michael Guetlein, who leads the Golden Dome program, said the budget was increased by $10 billion in part to fund development of a space-based data network. The Trump administration’s fiscal year 2027 budget request includes nearly $1.5 billion in research and development funding for the SDN backbone, along with another $2.38 billion in procurement funding to accelerate expansion of what budget documents describe as a proliferated low Earth orbit, or pLEO, mesh constellation and related ground infrastructure.

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