Ground Segment Cyber Defenses

Expanding SPARTA Across the Space System

SPARTA 4.0 extends its threat-informed cybersecurity guidance from the space and link segments to include the ground capabilities that develop, launch, command, monitor, and sustain space missions. This new ground segment resource complements SPARTA’s existing spacecraft-focused knowledge by providing a structured Defense-in-Depth framework, a functional decomposition of ground segment capabilities, and risk-based implementation guidance for protecting those functions. Together, these resources support a more integrated understanding of cybersecurity across the interconnected segments of a space system.

Ground Segment Cyber Defenses

Building off VTR-2026-00702 Rev A, Ground Segment Cyber Defenses and Risk-Based Tiering, we provide the following threat-informed guidance for applying Defense-in-Depth countermeasures across space system ground segment capabilities. The guidance organizes ground segment functions into six mission areas: Launch Integration and Operations, Mission Operations Center, Ground Station, Ground Networking Services, Ground Security Operations Center, and Ground Station as a Service. These mission areas and their associated function groups provide a common structure for understanding the cyber terrain that supports ground segment operations.

Not all organizations will perform every mission area, function group, or function depicted in the decomposition. Responsibilities may be distributed across internal systems, external partners, and commercial service providers based on the mission architecture and operating model.

The interactive ground segment functional decomposition below connects each function group to the Defense-in-Depth sub-layers and countermeasure targets relevant to protecting that capability. Select a function group within the figure to view its associated defensive guidance. These mappings were developed through threat-informed analysis that identified representative MITRE ATT&CK techniques for each function group and then selected Defense-in-Depth countermeasures that can mitigate those techniques. This approach helps system security engineers apply protections to specific mission functions rather than indiscriminately applying a single set of countermeasures across the entire ground segment.

Ground Segment Defense-in-Depth

The ground segment Defense-in-Depth framework organizes cybersecurity protections across eight layers: Prevention, Physical, Perimeter, Computer Network Defense and Incident Response, Network, Endpoint, Ground Software, and Data. These layers are further divided into specific sub-layers that define the defensive capabilities and implementation targets needed to provide complementary protection across the ground segment. Because no single countermeasure can prevent every adversary technique, protections should be coordinated across applicable layers so that the failure or bypass of one defensive capability does not readily expose critical mission functions.

For comprehensive ground segment protection, each Defense-in-Depth layer should be considered, but not every sub-layer or countermeasure will apply to every system or function. Ground segment architectures vary based on mission purpose, lifecycle phase, technology, organizational responsibilities, and the use of external partners or service providers. The mappings presented on this page therefore provide a recommended starting point for determining which defensive capabilities apply to each function group and should be further tailored to the system’s actual architecture and operational dependencies.

Baseline and Enhanced Countermeasures

The guidance provides two impact-based implementation tiers: Baseline and Enhanced. Baseline countermeasures are intended as the starting point for applicable functions supporting moderate mission impact and define the expected defensive capability when a Defense-in-Depth sub-layer applies. Enhanced countermeasures provide additional assurance for functions whose compromise could result in high mission impact or severe consequences. Enhanced countermeasures are applied in addition to, rather than in place of, the corresponding Baseline countermeasures.

Organizations should perform mission-specific criticality analysis to identify the functions most important to mission execution, safety, command authority, data integrity, and operational continuity, and then trace those functions to the applicable Defense-in-Depth sub-layers. This approach concentrates more advanced and resource-intensive protections on the capabilities where they provide the greatest mission risk reduction.

The full technical report, Ground Segment Cyber Defenses and Risk-Based Tiering – Revision A, provides the complete methodology, Defense-in-Depth definitions, risk-tier rationale, functional decomposition details, and an application of the framework to the Viasat KA-SAT attack. The accompanying Ground Segment Cyber Defenses Excel Workbook consolidates the report’s appendix tables into a single resource for filtering, reviewing, and applying the function mappings and Baseline and Enhanced countermeasure guidance.