Smart Contracts

Smart contracts provide an automated, consensus-based enforcement mechanism for security protocols governing data exchange across a spacecraft bus, particularly in hosted payload architectures where multiple independently operated payloads or subsystems share common infrastructure. By encoding security rules as deterministic contract logic, participating validator nodes can evaluate authenticated observations of bus activity and reach consensus on whether a defined violation occurred. A trusted bus controller, gateway, or access-control mechanism must then enforce any approved restriction because the smart contract itself cannot directly observe or block physical bus traffic. This approach is directly applicable to scenarios where a hosted payload is compromised or behaves maliciously, as the smart contract framework can detect the violation, achieve consensus among the remaining bus participants, and enforce exclusion of the offending payload before the attack propagates to other bus components or the host spacecraft. The consensus mechanism should prevent a single participating node from causing payload exclusion when the approved quorum and membership rules require agreement from multiple independent validators. Its effectiveness depends on the validator architecture, quorum threshold, communication assumptions, and number of compromised or unavailable validators. Smart contract-based enforcement is particularly valuable in multi-tenant spacecraft architectures where payload operators are organizationally distinct from the spacecraft bus operator and cannot be governed through a single chain of administrative control.

Sources

https://corpgov.law.harvard.edu/2018/05/26/an-introduction-to-smart-contracts-and-their-potential-and-inherent-limitations/

ID: CM0067

Tier: III

Onboard SV CM

Created: 2022/10/19

Last Modified: 2026/08/06

Pre-Operations Government

Acquisition requirements should address smart contract-based security enforcement as a design option for missions involving hosted payloads or multi-tenant bus architectures where independent payload operators share spacecraft infrastructure, with specifications defining the security protocols to be enforced by the contracts, the consensus mechanism to be used, the conditions that trigger violation detection, and the enforcement actions available to the contract upon consensus. Requirements should specify that the contract logic, validator functions, violation observations, and bus-enforcement mechanism be protected from modification by the payloads they govern. The consensus mechanism must tolerate the node failures and adversarial behavior identified in the mission threat model and must define safe behavior when the required quorum cannot be achieved. Contract language should require that the smart contract architecture be documented as a security engineering deliverable, including the security protocol rules encoded in the contracts, the consensus algorithm, the network participation requirements, and the enforcement actions and their reversibility, with the architecture subject to government technical review before implementation. Evaluation criteria should assess offerors' experience implementing smart contract frameworks in embedded or resource-constrained environments, their proposed consensus algorithm's resilience to adversarial node behavior, and their approach to maintaining contract integrity in the spacecraft's radiation and resource-constrained environment. Verification should include adversarial testing that simulates a compromised payload violating encoded security protocols, confirming that the violation is detected, consensus is achieved among remaining nodes, and the violating node is correctly barred from bus exchanges.

Pre-Operations Developer/Supplier

Smart contract architecture design must account for the resource constraints of the spacecraft bus environment, selecting consensus algorithms and contract execution engines that operate within the available processing, memory, and communication bandwidth budgets of the participating nodes without degrading the bus's primary operational functions. The security protocols to be enforced by smart contracts must be formally defined before contract development begins, with each protocol rule expressed with sufficient precision to be unambiguously evaluated by the contract logic; ambiguous or incomplete rule definitions will produce inconsistent enforcement behavior that adversaries can exploit to circumvent the intended protection. The consensus mechanism must be selected for its fault tolerance properties, choosing an algorithm that can achieve correct consensus even when a defined fraction of participating nodes behave arbitrarily or maliciously, with the maximum tolerable fraction of adversarial nodes determined by the mission's threat model. Contract logic and the enforcement node software must be stored in integrity-protected memory and verified through cryptographic integrity checks before execution, ensuring that a compromised payload cannot modify the contract code that governs its own behavior. The reversibility of enforcement actions, such as whether a barred payload can be reinstated after investigation and remediation, must be defined in the contract design and require authorization from a defined set of trusted principals rather than being executable by any single node.

Sustainment & Maintenance Government

Operational smart contract maintenance requires that the contract logic, consensus parameters, and participating node configuration be treated as controlled configuration artifacts, with any proposed modification reviewed and approved by all parties whose bus access rights are governed by the contracts before the update is deployed. Monitoring of contract execution should include automated alerting on violation detection events, consensus failures, and unexpected changes in participating node status, with each alert category associated with defined investigation and response procedures. Software updates to any bus node that participates in the consensus mechanism must be evaluated for their impact on consensus behavior and contract execution before deployment, as changes to node software can alter voting behavior in ways that affect the integrity of the collective enforcement mechanism. Post-enforcement reviews following any payload exclusion event should produce a documented assessment of the violation, the consensus process, the enforcement action, and whether the excluded payload's behavior indicated a cyber attack, providing both an audit record and lessons learned that inform future contract rule refinement.

Sustainment & Maintenance Developer/Supplier

Techniques Addressed by Countermeasure

ID	Name	Description
IA-0006	Compromise Hosted Payload	Adversaries target hosted payloads as an alternate doorway into the host spacecraft. Hosted payloads often expose their own command sets, file services, and telemetry paths, sometimes via the host’s TT&C chain, sometimes through a parallel ground infrastructure under different operational control. Initial access arises when an attacker obtains the ability to issue payload commands, upload files, or alter memory/register state on the hosted unit. Because data and control must traverse an interface to the host bus (power, time, housekeeping, data routing, gateway processors), the payload–host boundary can also carry management functions: mode transitions, table loads, firmware updates, and cross-strapped links that appear only in maintenance or contingency modes. With knowledge of the interface specification and command dictionaries, a threat actor can activate rarely used modes, inject crafted data products, or trigger gateway behaviors that extend influence beyond the payload itself. In multi-tenant or commercial hosting arrangements, differences in keying, procedures, or scheduling between the payload operator and the bus operator provide additional opportunity for a first foothold that looks like routine payload commanding.
IA-0013	Compromise Host Spacecraft	The inverse of "IA-0006: Compromise Hosted Payload", this technique describes adversaries that are targeting a hosted payload, the host space vehicle (SV) can serve as an initial access vector to compromise the payload through vulnerabilities in the SV's onboard systems, communication interfaces, or software. If the SV's command and control systems are exploited, an attacker could gain unauthorized access to the vehicle's internal network. Once inside, the attacker may laterally move to the hosted payload, particularly if it shares data buses, processors, or communication links with the vehicle.
LM-0001	Hosted Payload	The adversary pivots through the host–payload boundary to reach additional subsystems. Hosted payloads exchange power, time, housekeeping, and data with the bus via defined gateways (e.g., SpaceWire, 1553, Ethernet) and often support file services, table loads, and command dictionaries distinct from the host’s. A foothold on the payload can be used to inject traffic through the gateway processor, request privileged services (time/ephemeris distribution, firmware loads), or ride shared backplanes where payload traffic is bridged into C&DH networks. In some designs, payload processes execute on host compute or expose maintenance modes that temporarily widen access, creating paths from the payload into attitude, power, storage, or recorder resources. The movement is transitive: compromise a co-resident unit, then traverse the trusted interface that already exists for mission operations.
LM-0002	Exploit Lack of Bus Segregation	On flat architectures, where remote terminals, subsystems, and payloads share a common bus with minimal partitioning, any node that can transmit may influence many others. An attacker leverages this by forging message IDs or terminal addresses, replaying actuator/sensor frames, seizing or imitating bus-controller roles, or abusing gateway bridges that forward traffic between links (e.g., 1553↔SpaceWire/CAN). Because consumers often act on the latest valid-looking message, crafted traffic from one compromised device can reconfigure peers, toggle power domains, or write persistent parameters. Weak role enforcement and broadcast semantics allow privilege escalation from a peripheral to effective system-wide influence, turning the shared medium into a highway for further compromise.
LM-0003	Constellation Hopping via Crosslink	In networks where vehicles exchange data over inter-satellite links, a compromise on one spacecraft becomes a springboard to others. The attacker crafts crosslink traffic, routing updates, service advertisements, time/ephemeris distribution, file or tasking messages, that appears to originate from a trusted neighbor and targets gateway functions that bridge crosslink traffic into command/data paths. Once accepted, those messages can queue procedures, deliver configuration/table edits, or open file transfer sessions on adjacent vehicles. In mesh or hub-and-spoke constellations, this enables “hop-by-hop” spread: a single foothold uses shared trust and protocol uniformity to reach additional satellites without contacting the ground segment.
LM-0004	Visiting Vehicle Interface(s)	Docking, berthing, or short-duration attach events create high-trust, high-bandwidth connections between vehicles. During these operations, automatic sequences verify latches, exchange status, synchronize time, and enable umbilicals that carry data and power; maintenance tools may also push firmware or tables across the interface. An attacker positioned on the visiting vehicle can exploit these handshakes and service channels to inject commands, transfer files, or access bus gateways on the host. Because many actions are expected “just after dock,” malicious traffic can ride the same procedures that commission the interface, allowing lateral movement from the visiting craft into the target spacecraft’s C&DH, payload, or support subsystems.

Space Threats Addressed by Countermeasure

ID	Description
SV-AC-6	Three main parts of S/C. CPU, memory, I/O interfaces with parallel and/or serial ports. These are connected via busses (i.e., 1553) and need segregated. Supply chain attack on CPU (FPGA/ASICs), supply chain attack to get malware burned into memory through the development process, and rogue RTs on 1553 bus via hosted payloads are all threats. Security or fault management being disabled by non-mission critical or payload; fault injection or MiTM into the 1553 Bus - China has developed fault injector for 1553 - this could be a hosted payload attack if payload has access to main 1553 bus; One piece of FSW affecting another. Things are not containerized from the OS or FSW perspective;
SV-MA-8	Payload (or other component) is told to constantly sense or emit or run whatever mission it had to the point that it drained the battery constantly / operated in a loop at maximum power until the battery is depleted.
SV-AC-1	Attempting access to an access-controlled system resulting in unauthorized access

Sample Requirements

SPARTA ID	Requirement	Rationale/Additional Guidance/Notes
SPR-3	The [spacecraft] shall enforce approved authorizations for controlling the flow of information within the platform and between interconnected systems so that information does not leave the platform boundary unless it is encrypted. Flow control shall be implemented in conjunction with protected processing domains, security‑policy filters with fully enumerated formats, and a default‑deny communications baseline.{SV-AC-6}{AC-3(3),AC-3(4),AC-4,AC-4(2),AC-4(6),AC-4(21),CA-3,CA-3(6),CA-3(7),CA-9,IA-9,SA-8(19),SC-8(1),SC-16(3)}	Spacecraft operate in constrained and deterministic environments where uncontrolled data flows can enable data exfiltration, cross-domain leakage, or lateral movement between subsystems. Enforcing approved authorizations with enumerated formats and a default-deny posture ensures only explicitly permitted communications occur. Encryption enforcement at platform boundaries prevents unauthorized disclosure of telemetry or state information.
SPR-4	The [spacecraft] security implementation shall ensure that information should not be allowed to flow between partitioned applications unless explicitly permitted by the system.{SV-AC-6,SV-MA-3,SV-SP-7}{AC-3(3),AC-3(4),AC-4,AC-4(6),AC-4(21),CA-9,IA-9,SA-8(3),SA-8(18),SA-8(19),SC-2(2),SC-7(29),SC-16,SC-32}	Strict partitioning prevents compromise of one application from cascading into mission-critical subsystems. Many spacecraft attacks exploit flat architectures where subsystems implicitly trust one another. Explicit inter-partition authorization limits lateral movement and privilege escalation. This supports containment and fault isolation under both cyber and fault conditions.
SPR-14	The [spacecraft] shall authenticate the ground station (and all commands) and other spacecraft before establishing remote connections using bidirectional authentication that is cryptographically based.{SV-AC-1,SV-AC-2}{AC-3,AC-17,AC-17(2),AC-17(10),AC-18(1),AC-20,IA-3(1),IA-4,IA-4(9),IA-7,IA-9,SA-8(18),SA-8(19),SA-9(2),SC-7(11),SC-16(1),SC-16(2),SC-16(3),SC-23(3),SI-3(9)}	Authorization can include embedding opcodes in command strings, using trusted authentication protocols, identifying proper link characteristics such as emitter location, expected range of receive power, expected modulation, data rates, communication protocols, beamwidth, etc.; and tracking command counter increments against expected values.
SPR-21	The [spacecraft], when transferring information between different security domains, shall implement security‑policy filters that require fully enumerated formats that restrict data structure and content.{SV-AC-6}{AC-3(3),AC-3(4),AC-4(14),IA-9,SA-8(19),SC-16,SI-10}	Fully enumerated formats prevent injection of malformed or malicious data across security domains. This reduces parser exploitation, data smuggling, and covert channel abuse. Strict domain filtering supports deterministic and auditable inter-domain communication. Only explicitly defined data structures should be permitted.
SPR-26	The [spacecraft] shall use protected processing domains to enforce the policy that information does not leave the platform boundary unless it is encrypted as a basis for flow‑control decisions and shall enumerate permitted inter‑domain flows and enforce domain‑gate checks on any domain switch. {SV-AC-6}{AC-4(2),IA-9,SA-8(19),SC-8(1),SC-16(3)}	Domain gates provide controlled transition points between security domains. Enumerated flows prevent unintentional data leakage and enforce encryption policies at boundaries. This mitigates cross-domain injection and exfiltration. Strong gate enforcement prevents privilege escalation during context switching.
SPR-46	The [spacecraft] shall monitor [Program‑defined telemetry points] for malicious commanding attempts and alert ground operators upon detection.{SV-AC-2,SV-IT-1,SV-DCO-1}{AC-17,AC-17(1),AC-17(10),AU-3(1),RA-10,SC-7,SC-16,SC-16(2),SC-16(3),SI-3(8),SI-4,SI-4(1),SI-4(13),SI-4(24),SI-4(25),SI-10(6)}	Telemetry-based detection enables identification of anomalous command patterns, replay attempts, and injection attacks. Early detection allows rapid containment before mission impact escalates. Onboard monitoring is critical when ground latency limits intervention. This supports proactive defense.
SPR-55	The [spacecraft] shall provide cyber threat status to the ground segment for the Defensive Cyber Operations team, per the governing specification.{SV-DCO-1}{IR-5,PM-16,PM-16(1),RA-3(3),RA-10,SI-4,SI-4(1),SI-4(24),SI-7(7)}	The future space enterprises will include full-time Cyber Defense teams supporting space mission systems. Their work is currently focused on the ground segment but may eventually require specific data from the space segment for their successful operation. This requirement is a placeholder to ensure that any DCO-related requirements are taken into consideration for this document.
SPR-57	The [spacecraft] shall monitor and collect all onboard cyber- data (from multiple system components), including identification of potential attacks and information about the attack for subsequent analysis.{SV-DCO-1}{AC-6(9),AC-20,AC-20(1),AU-2,AU-12,IR-4,IR-4(1),RA-10,SI-3,SI-3(10),SI-4,SI-4(1),SI-4(2),SI-4(7),SI-4(24)}	The spacecraft will monitor and collect data that provides accountability of activity occurring onboard the spacecraft. Due to resource limitations on the spacecraft, analysis must be performed to determine which data is critical for retention and which can be filtered. Full system coverage of data and actions is desired as an objective; it will likely be impractical due to the resource limitations. “Cyber-relevant data” refers to all data and actions deemed necessary to support accountability and awareness of onboard cyber activities for the mission. This would include data that may indicate abnormal activities, critical configuration parameters, transmissions on onboard networks, command logging, or other such data items. This set of data items should be identified early in the system requirements and design phase. Cyber-relevant data should support the ability to assess whether abnormal events are unintended anomalies or actual cyber threats. Actual cyber threats may rarely or never occur, but non-threat anomalies occur regularly. The ability to filter out cyber threats for non-cyber threats in relevant time would provide a needed capability. Examples could include successful and unsuccessful attempts to access, modify, or delete privileges, security objects, security levels, or categories of information (e.g., classification levels).
SPR-59	The [spacecraft] shall attribute cyber attacks and identify unauthorized use of the platform by downlinking onboard cyber information to the mission ground station within [Program‑defined time ≤ 3 minutes].{SV-DCO-1,SV-IT-1,SV-IT-2}{AU-4(1),IR-4,IR-4(1),IR-4(12),IR-4(13),RA-10,SA-8(22),SI-3,SI-3(10),SI-4,SI-4(5),SI-4(7),SI-4(12),SI-4(24)}	Rapid transmission of cyber-relevant telemetry supports near-real-time ground-based fusion and correlation with enterprise security events. Delayed reporting increases risk of adversary persistence or mission degradation. Early attribution enables containment actions before cascading effects occur. Defined timeliness ensures detection capability aligns with operational tempo.
SPR-63	The [spacecraft] shall be able to locate the onboard origin of a cyber attack and alert ground operators within [Program‑defined time ≤ 3 minutes].{SV-DCO-1}{IR-4,IR-4(1),IR-4(12),IR-4(13),RA-10,SA-8(22),SI-3,SI-3(10),SI-4,SI-4(1),SI-4(7),SI-4(12),SI-4(16),SI-4(24)}	The origin of any attack onboard the vehicle should be identifiable to support mitigation. At the very least, attacks from critical element (safety-critical or higher-attack surface) components should be locatable quickly so that timely action can occur.
SPR-64	The [spacecraft] shall detect and deny unauthorized outgoing communications posing a threat to the spacecraft.{SV-DCO-1}{IR-4,IR-4(1),RA-5(4),RA-10,SC-7(9),SC-7(10),SI-4,SI-4(1),SI-4(4),SI-4(7),SI-4(11),SI-4(13),SI-4(24),SI-4(25)}	Outbound communications may indicate data exfiltration, covert channels, or compromised subsystem behavior. Monitoring and blocking unauthorized egress prevents leakage of mission data or cryptographic material. Many attacks rely on command-and-control or data extraction channels; egress control disrupts this persistence mechanism. Outbound traffic should be as tightly controlled as inbound command paths.
SPR-66	The [spacecraft] shall be designed and configured so that encrypted communications traffic and data is visible to on-board security monitoring tools.{SV-DCO-1}{RA-10,SA-8(21),SI-3,SI-3(10),SI-4,SI-4(1),SI-4(10),SI-4(13),SI-4(24),SI-4(25)}	Encryption must not blind onboard intrusion detection capabilities. Security tools require access to sufficient context (pre-encryption or post-decryption inspection points) to detect malicious patterns. Without visibility, encrypted channels become covert channels. Proper architectural placement ensures both confidentiality and detectability are preserved.
SPR-67	The [spacecraft] shall be designed and configured so that spacecraft memory can be monitored by the on-board intrusion detection/prevention capability.{SV-DCO-1}{RA-10,SA-8(21),SI-3,SI-3(10),SI-4,SI-4(1),SI-4(24),SI-16}	Many spacecraft attacks target memory corruption, firmware modification, or unauthorized process injection. Monitoring memory state enables detection of tampering, abnormal writes, or execution anomalies. Memory visibility supports early detection of wiper malware or boot-level compromise. This is essential for protecting deterministic flight software environments.
SPR-68	The [spacecraft] shall have on-board intrusion detection/prevention system that monitors the mission critical components or systems.{SV-AC-1,SV-AC-2,SV-MA-4}{RA-10,SC-7,SI-3,SI-3(8),SI-4,SI-4(1),SI-4(7),SI-4(13),SI-4(24),SI-4(25),SI-10(6)}	The mission critical components or systems could be GNC/Attitude Control, C&DH, TT&C, Fault Management.
SPR-69	The [spacecraft] shall alert in the event of the audit/logging processing failures.{SV-DCO-1}{AU-5,AU-5(1),AU-5(2),SI-3,SI-4,SI-4(1),SI-4(7),SI-4(12),SI-4(24)}	Failure of logging mechanisms may signal active tampering or resource exhaustion attacks. Immediate alerting ensures loss of visibility does not go unnoticed. Silent failure of audit systems creates blind spots exploitable by adversaries. Monitoring the monitors is critical to resilient detection.
SPR-70	The [spacecraft] shall provide an alert immediately to [at a minimum the mission director, administrators, and security officers] when the following failure events occur: [minimally but not limited to: auditing software/hardware errors; failures in the audit capturing mechanisms; and audit storage capacity reaching 95%, 99%, and 100%] of allocated capacity, including security component failover events; alerts shall include component identity, time, and fault reason.{SV-DCO-1}{AU-5,AU-5(1),AU-5(2),SI-4,SI-4(1),SI-4(7),SI-4(12),SI-4(24),SI-7(7)}	Intent is to have human on the ground be alerted to failures. This can be decomposed to SV to generate telemetry and to Ground to alert.
SPR-71	The [spacecraft] shall provide the capability of a cyber “black-box” to capture necessary data for cyber forensics of threat signatures and anomaly resolution when cyber attacks are detected. The [spacecraft] shall automatically route audit events to the alternate audit logging capability upon primary audit failure and shall resynchronize the alternate store to the primary upon recovery.{SV-DCO-1}{AU-5(5),AU-9(2),AU-9(3),AU-12,IR-4(12),IR-4(13),IR-5(1),SI-3,SI-3(10),SI-4,SI-4(1),SI-4(7),SI-4(24),SI-7(7)}	Similar concept of a "black box" on an aircraft where all critical information is stored for post forensic analysis. Black box can be used to record CPU utilization, GNC physical parameters, audit records, memory contents, TT&C data points, etc. The timeframe is dependent upon implementation but needs to meet the intent of the requirement. For example, 30 days may suffice.
SPR-468	The [spacecraft] shall detect and report the connection of any unauthorized or unknown component to onboard interfaces.{SV-SP-5,SV-SP-4}{PE-20,CM-8(3),SI-4}	Hardware implants pose existential mission risk. Detection of unknown components prevents covert insertion. Automated alerting reduces dwell time. Inventory integrity supports physical security.
SPR-495	The [spacecraft] shall detect impending failure of security components and initiate controlled failover to preserve confidentiality, integrity, and availability.{SV-MA-5,SV-DCO-1}{SI-4,SI-13,CP-10}	Early detection prevents cascading compromise. Controlled switchover maintains CIA properties. Structured alerting enhances situational awareness. Fault handling preserves assurance.
SPR-517	The [organization] shall correlate station/operator session activity with pass schedules and spacecraft mode, alert on off‑schedule access and command families invalid for the current mode, and retain results as audit evidence.{SV-AC-4,SV-AC-1,SV-AV-4}{AC-17,AC-17(1),SI-4,AU-6}	Off-schedule or mode-inconsistent commands signal compromise. Correlation across dimensions strengthens anomaly detection. Audit retention supports post-event review. Context validation strengthens mission assurance.
SPR-532	The [spacecraft] shall authenticate inter‑service exchanges (e.g., planning > command stacks, payload summaries > bus) using message‑level MACs/signatures or mutually authenticated channels appropriate to resource limits, and shall verify provenance for code‑driven actions.{SV-IT-1,SV-AC-2}{IA-9,AC-4}	Internal services must not assume implicit trust. Message-level authentication prevents spoofing. Resource-appropriate methods balance cost and assurance. Provenance verification strengthens command chain integrity.
SPR-534	The [organization] shall deploy deception/canary artifacts in ground TT&C environments (e.g., decoy credentials, fake repositories, canary procedures that never propagate to flight) and integrate alerts into incident handling; mechanisms shall not induce hazardous commanding.{SV-AC-4,SV-MA-7}{IR-4,IR-4(12),SI-4}	Canary artifacts reveal credential misuse or lateral movement. Integration with incident handling accelerates response. Mechanisms must not impact flight safety. Controlled deception strengthens detection.

Smart Contracts

Sources

Pre-Operations Government

Pre-Operations Developer/Supplier

Sustainment & Maintenance Government

Sustainment & Maintenance Developer/Supplier

NIST Rev5 Controls

D3FEND Techniques

D3FEND Artifacts

ISO 27001

NASA Best Practice Guide

ESA Space Shield Mitigation

Related MITRE EMB3D Mitigations

Related CSF 2.0

Related BSI Security Measures

Techniques Addressed by Countermeasure

Space Threats Addressed by Countermeasure

Sample Requirements