The practical value of health management in space exploration systems

There is a body of evidence, and a group of advocates, supporting the need for integrated system health management for space exploration systems. The advocates include operators responsible for complex and inherently risky decisions, and the technologists working in the domain of health management and looking for application for their products. Others in the decision loops take the view that health management is too expensive, or represents a technology paradigm shift that is not warranted. Within NASA, there have been two groups of technical experts studying this situation. Collectively, they have generated data supporting the view that health management systems have a positive impact on system safety, mission assurance and life cycle cost control. One of these groups is led by Bill Kahle and other NASA project managers, who have managed and/or proposed "technology risk reduction" demonstrations to increase the traditional technology readiness level (TRL) of health management processes and technologies. The experiments and demonstrations produce data needed for more ambitious health management technology applications. Well funded and successful within the constraints of the approved programs and projects, these demonstrations nevertheless have had limited success persuading decision makers, managers and designers of new and proposed programs to incorporate system-level health management technologies. The other group is led by Jim Miller and supported the NASA space architect's CRAI (capabilities, requirements, analyses, and integration) efforts by developing a capabilities breakdown structure (CBS) for the domain of IAHM&C (integrated avionics, health management, and controls). The CBS identifies the critical capabilities, provides definitions and metrics by which the effectiveness of these capabilities may be measured, and assessed the state of the art of these capabilities against a set of hypothetical scenarios (architectures) put forth for implementing the new exploration initiative. In the aggregate, the two groups define a comprehensive view that is required to accommodate and support the annual funding profile that program managers deal with continually, and which typically tends to obscure health management progress. Notwithstanding fiscal variability, funding health management piecemeal can still result in specific, quantifiable, and practical value to the overall health management goals. This paper provides insight into the thought processes and conclusions of these teams and reflects the thoroughness and specificity of the recommended investment areas and investment strategies. The authors propose that NASA need not make the total investment in these technologies since there is a considerable need and commensurate investment in the defense and private industry. The paper does not recommend a specific set of technologies for specific exploration application scenarios since these scenarios have not yet been fully developed. The paper does, however, reflect the view that integrated system health management is not a nebulous set of discretionary technologies that could probably be applied; but that these technologies do, in fact, represent valuable elements in the domain of system engineering that will lead to improved safety and the increased likelihood of mission success