1. Maintaining Unmaintainable Systems
Jim Van Laak
SAE Aerospace Standards Summit
10/3/2018

2. The Challenge Robotic systems are becoming ubiquitous
Well suited to hostile and distant locations
Once deployed, maintenance is difficult or impossible
Three potential paths:
Make systems inexpensive and expendable
Achieve extreme levels of reliability
System self-recovery (including maintenance)

3. Option 1: Inexpensive and Expendable
Space systems tend to be expensive
High performance, low mass, low margin
Significant launch and support costs (operations and engineering)
Systems can be made less expensive
More COTS elements, commercial manufacturing and processing
BUT potential for reduced reliability is real
Goal is to find sweet spot for reliability, performance, and cost
Faster-Better-Cheaper was an honest attempt to do this
Poor results due mainly to poor individual decisions

4. Option 2: Achieve Extreme Reliability
Reliability is difficult to guarantee in space systems
Quantities are very low so statistics are not helpful
Many environments have large unknowns, opening door to design failures
Cost/benefit ratio for quality is asymptotic
The easy part has already been done
Most modern products have excellent reliability within design envelope
Consequences of failure for space systems can be severe

5. Unintended Consequences
Extreme reliability comes at extreme cost
Betting on perfection
Creates vicious cycle: cost – criticality – perfection – more cost
Example: Space Shuttle lack of crew escape system
Operations must make perfect decisions
Such perfection is difficult to maintain over time
Conservative decisions reduce system performance
Over-confidence becomes a major force in decision process

6. Option 3: Self-recovery
Diagnostics
First step is knowing what is going on
System architecture
Robust design for inherent reliability and graceful degradation
Autonomy
Reduce support costs and time criticality
Introduces significant risk – only as smart as human designers
Robotics
Limited scope
High system impact for access and compatibility
Significant probability of error (K-factors)

7. Summary
Achieving high reliability in unmanned systems is very challenging
Maintenance can contribute but is not a panacea
System architecture is key
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