Space Digital Integrated Network (SDIN)

The Space Digital Integrated Network (SDIN) is a critical communications infrastructure managed by the United States Space Force. Originally developed in the 1980s under the Air Force Space Command as the Space Defense Interface Network, its primary goal is to facilitate secure and reliable communications between missile warning and missile tracking sensors and command and control (C2) nodes. This supports both nuclear deterrence and missile defense operations. Over time, the network has expanded its role to encompass all Space Force mission areas, providing connectivity to nearly every Space Force operating location.

SDIN's objectives include supporting a wide range of operational requirements such as Space Domain Awareness (SDA) sensor integration and communications for advanced beyond line-of-sight terminals. It also supports ground segment communications for infrared systems, as well as intra-base and inter-base communications between Space Operations Centers (SOCs) and other force elements. Additionally, SDIN supports long local communications and Land Mobile Radio systems, making it a foundational element for Space Force command, control, and communications.

The FY 2026 budget request for SDIN represents a new start for the program, with a specific focus on modernization. The justification for this investment is rooted in the need to address the obsolescence of legacy hardware, much of which was last upgraded in 2012. Many components are now approaching end-of-life, posing risks to operational continuity and mission assurance. The modernization effort aims to ensure the network remains resilient, secure, and capable of supporting evolving mission requirements.

Key objectives for the FY 2026 SDIN modernization include conducting a comprehensive architectural analysis of the existing network, procuring updated hardware, and performing integration and installation activities at Space Force operating locations. These activities are designed to enhance the reliability, security, and scalability of the network, ensuring it can support current and future mission demands. The modernization will also address cybersecurity requirements and interoperability with other Department of Defense (DoD) and allied networks.

The Space Force is the lead agency for the SDIN program, with oversight and execution responsibilities for procurement, integration, and installation. The program does not have related Major Defense Acquisition Program (MDAP) or Major Automated Information System (MAIS) codes, and there are no other related program elements identified in the budget justification. This underscores the unique and specialized nature of the SDIN within the broader Space Force portfolio.