Anomaly Criteria
Anomalies are unexpected events that deviates from the normal operation of spacecraft systems or mission parameters.
Time-Critical Anomalies
During our time at NASA, we were particularly interested in time-critical anomalies that required urgent diagnosis.
| Criteria | Definition |
|---|---|
| Urgent | The problem is connected to a critical system, for example the oxygen system on a spacecraft |
| Unanticipated | There is no procedure or checklist to resolve the issue |
| Unknown | The problem has an unknown origin, doesn't know where the problem came from |
Credits: McTigue, K., Panontin, T., Duncan, K.
This type of anomaly is especially dangerous as in the past 15 years with ISS missions, the EIO Lab at Ames has identified that they occur about 1.7 times per year. When extrapolated to the Mars mission, it means that astronauts are more likely to encounter multiple time-critical anomalies throughout the Mars mission. At the same time, Mission Control will no longer be able to provide immediate assistance, and the crew will have to be able to address the issues on their own.
Four Key Characteristics
① Causal relationships are not immediately understood
- Competing alarms across systems - challenge of isolating the initiation
- Specific expertise required; challenge of "from 80+ people to 4" working the problem
- Complexity of system and of anomaly
- Challenge of safely perturbing the system to gain understanding of cause and effect
② Limited intervention options
- Creativity required to generate workaround options
- Systems thinking to perform risk assessments
- Rapid synthesis and decision-making
- Resource limited environment, limited redundancy, sparing, etc.
- Procedures may have unexpected outcomes
③ No perfect information during initial stages
- Sensors data may be incorrect or incomplete
- Sensors are limited resource, do not cover all parts of the system
- Historical data may be limited or unavailable
- Challenge to parse out relevant data
④ Time pressure
- Short time-to-effect (to prevent adverse outcomes)
- Time pressure on execution/completion of procedure
- Competing priorities (e.g., inattention to other critical operations)
- Simultaneous efforts required (safing, investigating, downstream impact)
Credits: CMU Kickoff 2024, McTigue, K., Duncan, K.