Assessing Changeability in Aerospace Systems Architecting and Design Using Dynamic Multi-Attribute Tradespace Exploration

A framework for assessing changeability in the context of dynamic Multi-Attribute Tradespace Exploration (MATE) is proposed and applied to three aerospace systems. The framework consists of two parts. First, changeability concepts such as flexibility, scalability, and robustness are defined in a value-centric context. These system properties are shown to relate “real-space to value-space” dynamic mappings to stakeholder-defined subjective “acceptable cost” thresholds. Second, network analysis is applied to a series of temporally linked tradespaces, allowing for the quantification of changeability as a decision metric for comparison across system architecture and design options. The quantifiable is defined as the filtered outdegree of each design node in a tradespace network formed by linking design options through explicitly defined prospective transition paths. Each of the system application studies are assessed in the two part framework and within each study, observations are made regarding the changeability of various design options. The three system applications include a hypothetical low Earth orbit satellite mission, a currently deployed weapon system, and a proposed large astronomical on-orbit observatory. Preliminary cross-application observations are made regarding the embedding of changeability into the system architecture or design. Results suggest that the low Earth orbit satellite mission can increase its changeability by having the ability to readily change its orbit. The weapon system can increase its changeability by continuing to embrace modularity, use of commercial off-the-shelf parts (COTS), and simple, excess capacity interfaces. The large astronomical observatory can increase its potential changeability by having the ability to reconfigure its physical payloads and reschedule its observing tasks. The analysis approach introduced in this paper is shown to be a powerful concept for focusing discussion, design, and assessment of the changeability of aerospace systems.