35
This
classification is presented in Fig. 12.
Operational/
Environmental
Discipline-
Level
Uncertainty
System-Level
Fig. 12.
Uncertainty Classification for Aircraft Systems Design.
35
11
3
rd
Annual Predictive Methods Conference, Newport Beach, California, June 2003
Operational/ environmental uncertainty is concerned with modeling how a vehicle or fleet of vehicles will be
utilized over its useful life.
System-level uncertainty is concerned with the requirements, synthesis, and predicted
performance of a vehicle.
Finally, discipline-level uncertainty is concerned with the various contributing analyses
that are required to synthesize vehicle alternatives.
Uncertainty research in space system design is very recent.
Ref. 34 defines uncertainty as “inability to quantify
precisely; a distribution that reflects potential outcome”.
Uncertainty is classified into development, operational,
and model.
34
Fig. 13 illustrates this classification and Table 7 defines these uncertainties.
Political
Development
Model
Requirements
Development cost
Development
schedule
Development
technology
Uncertainty
Political
Lifetime
Obsolescence
Integration
Operations cost
Market
Operational
Development
Operational
Fig. 13.
Uncertainty Classification for Space Architectures.
34
Table 7
Uncertainty Definitions for Space Architectures
34
Uncertainty
Subclassification
Uncertainty of …
Development
Political
development funding instability
Requirements
requirements stability
Cost
developing within a given budget
Schedule
developing within a given schedule profile
Technology
technology to provide performance benefits
Operational
Political
operational funding instability
Lifetime
performing to requirements in a given lifetime
Obsolescence
performing to evolving expectation in a given lifetime
Integration
operating within other necessary systems
Cost
meeting operations cost targets
Market
meeting demands of an unknown market
Model
n/a
no formal definition
This classification and associated definitions appears to build on the management classification provided by Ref. 15.
Ref. 34 does not provide significant details on uncertainty types beyond these definitions and primarily concerns
itself with mitigating uncertainty by portfolio management (drawing on an analogy to economics).
