Redundancy vs Mass Efficiency
Design functional-level redundancy strategies and document them in the safety case to satisfy IEC 61508 fault-tolerance requirements without defaulting to mass-intensive hardware duplication.
CyberTRIZ analysis · Space contradiction SDP011 · one of 8,235 worked contradictions published by CyberTRIZ.AI
Regulations
Business Context
Redundant components improve spacecraft fault tolerance by providing alternative equipment when primary hardware fails. However, duplicated computers, sensors, actuators, communications equipment, power electronics, and other subsystems increase mass, volume, power consumption, thermal loads, interfaces, and verification requirements. Excessive hardware redundancy can consume resources that would otherwise support payload capability or mission duration.
Space TRIZ Resolution
Rather than duplicating every critical component, spacecraft should provide redundancy at the functional level. Existing equipment can perform secondary functions during failures, software can reconfigure resources, and alternative operational modes can preserve essential capabilities with reduced performance. For distributed missions, redundancy can also exist across spacecraft or ground infrastructure instead of entirely within each vehicle.
Applicable TRIZ Principles
Principle 5 – Merging allows existing elements to share backup functions instead of adding dedicated duplicate hardware.
Principle 6 – Universality enables components to perform secondary functions during degraded conditions.
Principle 15 – Dynamics reconfigures available resources according to spacecraft condition.
Expected Outcome
Higher fault tolerance
Lower redundancy mass
Improved spacecraft resource efficiency
Greater resilience through functional alternatives
Decision Indicators
Early indicators include:
Backup equipment remains unused throughout most of the mission.
Redundancy represents a significant portion of spacecraft mass.
Multiple backup systems duplicate functions available elsewhere.
Reliability improvements consistently require additional hardware.
Functional reconfiguration receives limited consideration during reliability design.
Monitoring these indicators helps determine whether resilience can be achieved through functional rather than physical duplication.