In a modern world, importance of computer modeling for solving complex engineering problems cannot be overstated. However, in many cases environments are too complex, temporal and spatial scales are too diverse, and the nature of the physics processes are too complicated to provide a unique answer. Therefore, further physical and analytical insight is required to guide computer simulations. To address the complexity of the physical process at the interface of multiple engineering systems, a new discipline is emerging: physics based methods for the analysis of integrated vehicle environment. This discipline combines "old-fashioned" analytical physics based approach to modeling engineering problems with modern advanced technologies for analyzing continuous and discrete information flow involving multiple modes of operation in uncertain environments, unknown state variables, heterogeneous software and hardware components. Conceptually, critical physics analysis begins when observed effects cannot be understood within the scope of existing models, or when there is an unexplained discrepancy between the computer model predictions and experimental data, when root causes of system failure need to be understood, when a puzzle emerges from the nontrivial interplay between seemingly distant physics disciplines, when the vehicle performance is studied outside of nominal operational margins or the overly conservative margins and knockdown factors need to be improved. Critical physics analysis plays a major role in situations where substantially different environments, mission durations, operational modes, states and constraints exist that we do not yet understand with our existing experience. Best results can often be achieved by combining simplified physics-based models developed with theoretical methods and critical physics insight that helps to discern, qualify, and quantify key phenomena and causality relations within complex environments provided by computer simulations. This is, in turn, achieved through an interdisciplinary effort that combines computer simulations and physics analysis with laboratory and field experiments, mathematical modeling, optimization algorithms and data-driven techniques.
This approach is especially important in the era of limited funds, where we must optimize all science, technology, and risk reduction investments for development projects. Many problems that we face are integrated in nature, interrelated in solution, and interdependent in application. We should look for a way to prioritize, focus, and “solve the right problem.” There exists a deep interrelation between the physics-based approaches and Integrated System Health Management, diagnostics and prognostics. The objective of critical physics analysis here is to confine the space of designs, level of automation and fault management strategies to obey the set of constraints driven by the operational physics and to inform about possible increase in failure probability. It is also to develop physics of failure models predicting system degradation in exploitation cycles and due to environment. Development of leading-order physics models is also a necessity in Engineering Risk Assessment to capture the main cause-and-effect sequences and to perform sensitivity studies via quantitative models and explicit analysis of the physics-based interactions and mechanisms that drive operational risks. Overall, there is a significant and growing need in development of deep insights and simplified models to capture the nature of complex phenomena in operational-mission environments. At the same time, critical analysis based on fundamental physics investigations still remains a somewhat rare commodity in NASA experience---a “work of art”---that has been largely lost from NASA since the 1960s and 70s.
Fu-Kuo Chang, Stanford University
Shawn Beard, Acellent Technologies, Inc.
Cyrill Muratov, New Jersey Institute of Technology
Andre Petukhov, South Dakota School of Mines and Technology
Michael Watson, Marshall Space Flight Center
James Walker, Marshall Space Flight Center
Curtis Banks, Marshall Space Flight Center
Richard Tyson, University of Alabama Huntsville