CM0020 Threat modeling Threat modeling is a structured analytical process that identifies, enumerates, and prioritizes potential threats to a system by systematically examining assets, trust boundaries, data flows, and adversary capabilities relative to the system's architecture. Applied in combination with attack surface analysis and vulnerability analysis, threat modeling produces an integrated picture of where the system is most exposed and what the consequences of successful exploitation would be. Analysis should draw on findings from similar systems, components, or services where applicable, leveraging documented threat experience from comparable missions or architectures to avoid re-learning known lessons. The outputs of threat modeling must directly inform design decisions throughout the development process, with attack surface reduction treated as a design objective rather than a post-development hardening activity: interfaces, services, protocols, and code paths that are not necessary to mission function should be eliminated or constrained before they become embedded in the architecture. Threat model artifacts should be treated as living documents, updated as the system design evolves and as new threat intelligence becomes available.
CM0070 Alternate Communications Paths Establishing alternate communications paths for spacecraft and ground system operations reduces the likelihood that a single adversarial event, physical disruption, or technical failure will deny all mission communications. Reliance on a single communications pathway creates a single point of failure that adversaries can exploit through jamming, denial of service against ground infrastructure, physical disruption of a ground station, or compromise of network connectivity, any of which could result in complete loss of commanding and telemetry capability. Alternate paths must be assessed end to end for shared failure modes and operational dependencies. Differences in frequency, ground station, relay service, or network provider provide meaningful resilience only when the paths do not remain dependent on the same critical spacecraft, ground, management, or service infrastructure. The selection and configuration of alternate paths must be governed by the mission's concept of operations (CONOPS), which defines the conditions under which each path is used, the priority and switchover procedures between paths, and the minimum communications capability that must be maintained to satisfy mission safety and operational continuity requirements.
CM0071 Communication Physical Medium The physical medium selected for ground segment networking directly affects the mission's vulnerability to passive interception, traffic flow analysis, and electromagnetic eavesdropping, making medium selection a security design decision that must be informed by the mission's threat model. Fiber optic cabling transmits data optically and does not produce the same conducted or radiated electrical emanations as copper cabling, reducing exposure to proximity-based electromagnetic collection. Fiber may still be intercepted through physical access, optical coupling, compromised patch points, or endpoint equipment, and medium selection alone does not conceal traffic timing or volume from an observer with access to the link or its endpoints. Fiber should therefore be considered where the threat model identifies electromagnetic emanation or physical-medium interception risk, while cryptographic and physical protections remain applicable, particularly for links carrying mission-sensitive data such as command uplink traffic, cryptographic key material, or mission planning data. The selection of physical medium should be treated as a threat-informed engineering decision evaluated for each network segment based on the sensitivity of the data carried, the physical accessibility of the cabling, and the threat environment of the facility in which the cabling is installed.
CM0029 TRANSEC Transmission security (TRANSEC) is the component of communications security (COMSEC) concerned with protecting the characteristics of the transmission itself, as distinct from protecting the content of the information being communicated. TRANSEC controls reduce the likelihood, effectiveness, or operational impact of transmission interception, signal disruption, communications deception, and exploitation of transmission characteristics within the defined threat model. Applicable TRANSEC techniques include jam-resistant waveforms that increase resistance to jamming and communications deception, spread spectrum and frequency hopping techniques that reduce signal predictability and improve resistance to interception and disruption, low probability of intercept and low probability of detection (LPI/LPD) signal designs that reduce transmission observability, and transmission scheduling or pattern discipline that limits the intelligence value of traffic analysis. TRANSEC requirements should be applied to mission communication links according to link criticality (e.g., TT&C, crosslinks), threat exposure, and operational consequence. TRANSEC must be treated as a distinct layer of protection complementary to, but not a substitute for, cryptographic protection of information content.