L2-SLF-FDI
CRITICAL
ROBOTICS
Level 2 · software
Fault Detection and Isolation
Fault Detection, Diagnosis, and Isolation Engine
Anomaly detection across all systems with root cause analysis and fault tree reasoning
Purpose
Detect anomalous system behavior and isolate the root cause to specific components
Context
Component of L1-SLF within the Lunar Ark system
Principles
- ▸Model-based diagnosis compares observed behavior against expected system models
- ▸Bayesian fault diagnosis quantifies probability of each fault hypothesis
- ▸Fault tree analysis traces symptoms to root causes through causal logic
- ▸Anomaly detection identifies deviations from normal behavior patterns
Typical implementations
- ▸NASA ISHM (Integrated System Health Management) framework
- ▸Livingstone2 model-based diagnosis system (JPL/Ames)
- ▸GE Digital Twin fault diagnosis for industrial equipment
- ▸FDIR (Fault Detection, Isolation, Recovery) in ESA spacecraft
Lunar considerations
- ▸Must diagnose novel failure modes not anticipated in design
- ▸Cascading failure analysis critical due to tightly coupled Ark systems
- ▸Diagnosis must be fast enough to prevent secondary damage
- ▸100-year operational data improves diagnosis accuracy over time
Specifications
Functional
| primary function | Detect anomalous system behavior and isolate the root cause to specific components |
Operational
| thermal range c | -173, 127 |
| lifetime years | 100 |
Interfaces
Provides
- Diagnosed fault identification for reconfiguration decisions
- Root cause identification for repair action planning
Requires
- All system telemetry for fault detection analysis
- Structural health data for diagnosis correlation
Decomposes into
L3-SLF-FDI-MODEL
Model-Based Fault Diagnosis
Model-based fault diagnosis engine comparing observed system behaviour against expected (per L3-MNT-LIFE-TWIN digital tw
L3-SLF-FDI-BAYES
Bayesian Fault Inference
Bayesian network inferring fault probabilities from observed symptoms — provides probabilistic fault diagnoses with unce
L3-SLF-FDI-TREE
Fault Tree Analysis
Real-time fault tree traversal engine identifying root causes and downstream consequences of detected faults.
L3-SLF-FDI-ANOM
Anomaly Detector
ML anomaly detector identifying anomalous system behaviour not matching any known fault — flagging unknown fault modes f
Cite this entry
Lunar Ark Codex. "Fault Detection and Isolation" (L2-SLF-FDI). Retrieved 10 September 2026, from https://lunarark.com/entry/L2-SLF-FDI
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.