WASHINGTON, — May 27, 2026 : The U.S. Space Force has awarded SpaceX a $2.29 billion firm-fixed-price contract to develop the Space Data Network (SDN) Backbone, a proliferated low Earth orbit (pLEO) satellite constellation designed to provide resilient, high-capacity and low-latency military data transport worldwide.
The award, announced by Space Systems Command (SSC) on May 26, was issued under an Other Transaction Authority (OTA) agreement as part of the Space Force’s effort to build a hybrid space-based communications architecture capable of rapidly transferring operational data between military systems. Previously known as MILNET, the SDN Backbone is a joint initiative between the Space Force and the National Reconnaissance Office (NRO), aimed at moving information from sensors to operational shooters worldwide by integrating military and commercial satellite capabilities.
According to Space Systems Command, the SDN Backbone will serve as an integrated network providing robust, resilient, high-capacity and low-latency data transport while supporting worldwide tactical communications and broadband services. The system is intended to function as a core communications layer connecting satellites, sensors, command systems and weapons platforms to enable near real-time data movement during military operations.
SpaceX to Deliver Operational Prototype by 2027
Under the agreement, SpaceX is required to provide a fully operational prototype capability by the end of 2027. The service, however, has not confirmed whether the effort will involve launching newly built satellites or leveraging spacecraft already operating in orbit.
The architecture is based on SpaceX’s Starshield satellites, a militarized version of the Starlink platform developed for national security applications. The constellation will operate in proliferated low Earth orbit and function as an optically interconnected mesh network, allowing data to move across multiple satellites efficiently and securely. The SDN Backbone is expected to become the foundational backhaul layer of the broader Space Data Network architecture.
Satellite Procurement and Budget Expansion
Space Force budget documents indicate the service plans to procure 13 satellites for the Space Data Network in fiscal year 2026, followed by 21 satellites in fiscal year 2027 as part of the initial deployment phases. Earlier planning documents for the MILNET program referenced a potential constellation of approximately 480 satellites, although current efforts remain focused on early procurement tranches and operational capability.
Funding allocated to the program reflects a significant expansion in investment. While the fiscal year 2026 budget allocated approximately $277 million for MILNET, the fiscal year 2027 request includes nearly $1.5 billion for SDN Backbone research and development and approximately $1.6 billion for procurement activities, indicating a larger push toward proliferated low Earth orbit communications infrastructure.
The broader Space Data Network will also include a Mission Operations Center responsible for managing the hybrid transport constellation and coordinating operational data movement across the system.
Competitive Contracting and Industrial Base Expansion
Space Systems Command stated the SpaceX award was made through a competitive process but did not immediately confirm whether additional bids were submitted. A Space Force spokesperson previously stated that the service intends to strengthen the U.S. industrial base to meet future proliferation requirements and continues efforts to identify additional contractors capable of building SDN satellites and supporting architecture components.
Lt. Col. Jeffrey Fry, SDN Backbone system program manager, said competition remains central to the acquisition strategy.
“Our acquisition strategy is designed to foster competition and broaden our industrial base,” Fry stated. “We aren’t trading speed for scale; we are demanding both. By using rapid prototyping and Other Transaction Authorities, we are ensuring our advanced solutions are integrated and delivered to the warfighter as fast as possible.”
Integration With Wider Defense Space Architecture
The SDN Backbone will operate alongside the Space Development Agency’s Transport Layer, with both systems intended to create a unified and open architecture supporting current and future Department of Defense missions. Together, the systems are expected to provide resilient global connectivity for military data transport requirements.
To support interoperability across the constellation, the Space Force is also advancing the Enterprise Space Terminal (EST) program. Contractors including CACI, General Atomics and Viasat are developing standardized long-range laser communication terminals designed to implement common waveforms and enable crosslink compatibility between satellites across the network.
Col. Ryan Frazier, acting Portfolio Acquisition Executive for Space-Based Sensing and Targeting, said the SDN Backbone will strengthen the Space Force’s ability to maintain continuous, global and secure communications between military systems.
“The SDN Backbone leverages the best of commercial innovation and delivers a strong foundation for the SDN mission set,” Frazier stated. “The SDN Backbone supports the broader SDN, which acts as a core communications layer for the U.S. Space Force warfighting systems, ensuring our sensors and shooters are connected continuously, globally and securely.”
Space Systems Command, which oversees a $15.6 billion annual space acquisition portfolio, is responsible for acquiring, developing and delivering the SDN Backbone through its Portfolio Acquisition Executive for Space-Based Sensing and Targeting as the broader architecture continues development.
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