WASHINGTON ― The Space Force today announced it has awarded SpaceX $2.29 billion to “accelerate” fielding of a “backbone” data transport constellation in low Earth orbit (LEO) for the Space Data Network (SDN), which the service is developing as its central communications network to link sensors to shooters.
Under the Other Transaction Authority agreement, the company is to deliver “a fully operational prototype capability by the end of 2027,” Space Systems Command (SSC) said in a press release.
The SDN Backbone, formerly known as MILNET and based on SpaceX’s Starshield militarized variant of its commercial Starlink constellation, will serve as the backhaul data transport layer for the broader SDN. While the award to SpaceX is thus not a surprise, the size of the contract is.
The service’s fiscal 2026 budget included $277 million for MILNET. The FY27 request asks for $1.5 billion in SDN Backbone research and development, and another $1.6 billion in procurement with both pots to be provided via the reconciliation package.
“The SDN Backbone is a pLEO [proliferated LEO] satellite constellation which functions as an integrated network, providing robust, resilient, high-capacity, and low-latency data transport for the Joint Force. This award will enhance the network with an expanded optically interconnected mesh of satellites delivering world-wide tactical communications and broadband communication services,” the release added.
Col. Ryan Frazier, acting Space Force portfolio acquisition executive for Space Based Sensing & Targeting, said in the release that the “SDN Backbone supports the broader SDN, which acts as a core communications layer for the USSF warfighting systems, ensuring our sensors and shooters are connected continuously, globally and securely.”
The SSC release explains that the Space Development Agency’s Transport Layer satellites in LEO are part of the broader SDN, which the service envisages as a future mesh network of various types of satellites in multiple orbits that among other missions will support the Pentagon’s Golden Dome missile defense shield.
