Reliability vs System Complexity
Prioritise fault prevention and functional simplification over additive redundancy to achieve required Safety Integrity Levels without compounding failure-mode complexity.
CyberTRIZ analysis · Space contradiction RMA001 · one of 8,235 worked contradictions published by CyberTRIZ.AI
Regulations
Business Context
Spacecraft require high reliability because failures after launch can be difficult or impossible to repair. Reliability is often increased through redundant hardware, additional monitoring, backup operating modes, fault-management software, protective mechanisms, and verification controls. However, each additional reliability feature introduces components, interfaces, software states, and interactions that can themselves become sources of failure. A spacecraft can therefore become more complex while attempting to become more reliable.
Space TRIZ Resolution
Reliability should be increased by eliminating failure mechanisms and simplifying critical functional paths before adding protective layers. Functions can be consolidated where appropriate, unnecessary interfaces removed, and existing spacecraft resources used for backup functions. Reliability architecture should prioritize fault prevention, functional reconfiguration, and graceful degradation rather than relying primarily on additional hardware.
Applicable TRIZ Principles
Principle 2 – Taking Out removes unnecessary components, interfaces, and failure mechanisms from critical functional paths.
Principle 6 – Universality allows existing spacecraft elements to provide backup or protective functions.
Principle 15 – Dynamics reconfigures available resources when failures or degraded conditions occur.
Expected Outcome
Higher mission reliability
Lower architectural complexity
Fewer failure-producing interfaces
Improved fault recovery capability
Decision Indicators
Early indicators include:
Reliability improvements consistently add new hardware or software layers.
Interface counts increase as fault protection expands.
Backup systems introduce additional failure modes.
Verification complexity grows faster than demonstrated reliability.
Operators struggle to understand interactions among protection mechanisms.
Monitoring these indicators helps determine whether reliability architecture is becoming a source of complexity rather than reducing mission risk.