An Information-Exchange Tool for Capturing and Communicating Decisions During Early-Phase Design and Concept Evaluation

Capturing and communicating risk and uncertainty for NASA’s low-volume high-cost exploration missions have become the subject of intensive research in the past few years. As a result, a variety of quantitative and qualitative methodologies were developed, some of which have been adopted and implemented by various NASA centers in the form of risk management tools, procedures, or guidelines. Most of these methodologies, however, aim at the later stages of the design process or during the operational phase of the mission and therefore, are not applicable to the earlier stages of design. In practice, however, uncertainties in the decisions made during the early stages of design introduce a significant amount of risk to the concepts that are being evaluated. In this paper, we aim to capture and quantify uncertainty and risk due to the lack of knowledge as well as those associated with potential system failures. We present an information exchange tool (X-Change) that enables various subsystem designers to capture, quantify, and communicate the uncertainties due to their lack of knowledge as well as those due to failures that might not be readily available or easily-quantifiable. A key piece in this work is to incorporate risk and uncertainty due to the lack of knowledge during the early design phase, and combining it with the potential failure modes. The challenges we face in accomplishing this goal are: 1) lack of a unified ontology defining risk, uncertainty and failure in order to enable their use on common grounds; 2) difficulty in expressing and capturing risk and uncertainty due to the designers’ lack of knowledge at the early stages of design; 3) difficulty in accounting for potential failure modes and their associated risks at the functional design level, before a form or solution has been determined. In order to address these challenges, this paper first attempts to provide a definition for risk and uncertainty. Then, we present the results of an ongoing effort to develop a risk-based design tool for the concurrent mission design environment at NASA. We propose a framework that enables multiple subsystems to capture and communicate the relevant risk and uncertainty in their decisions. The application of the proposed framework is further elaborated using a satellite design example.