Multi-Attribute Tradespace Exploration for Survivability: Application to Satellite Radar

Abstract

Multi-Attribute Tradespace Exploration (MATE) for Survivability is introduced as a general methodology for survivability analysis and demonstrated through an application to a satellite radar system. MATE for Survivability applies decision theory to the parametric modeling of thousands of design alternatives across representative distributions of disturbance environments. Survivability considerations are incorporated into the existing MATE process (i.e., a solution-generating and decision-making framework that applies decision theory to model-based design) by applying empirically-validated survivability design principles and value-based survivability metrics to concept generation and concept evaluation activities, respectively. MATE for Survivability consists of eight iterative phases: (1) define system value proposition, (2) generate concepts, (3) specify disturbances, (4) apply survivability principles, (5) model baseline system performance, (6) model impact of disturbances on dynamic system performance, (7) apply survivability metrics, and (8) select designs for further analysis. The application of MATE for Survivability to satellite radar demonstrates the importance of incorporating survivability considerations into conceptual design for identifying inherently survivable architectures that efficiently balance competing performance metrics of lifecycle cost, mission utility, and operational survivability. Nomenclature A T= threshold availability ∆V = change in velocity, m/s k i = multi-attribute utility scaling factor for attribute i TAT = time above critical value threshold, years T dl = time of design life, years U e = emergency utility threshold (zero by definition), utilities are dimensionless U i (x i ) = single-attribute utility function over attribute x i U ‾ L = time-weighted average utility loss from design utility, U 0 ‾ U t = time-weighted average utility U(t) = utility delivery over time; multi-attribute utility trajectory U(x) = multi-attribute utility function over attributes x at a point in time U x = required utility threshold

Multi-Attribute Tradespace Exploration for Survivability

“…Although the 760 designs that arise along the four-dimensional Pareto surface in the satellite radar tear tradespace are less than the 2268 in the unfiltered tradespace, they are significantly more than the 198 designs along the traditional Pareto front of cost and utility. 2 Therefore, having identified the region of optimal trade-offs among cost, utility, and survivability, it is particularly important to engage with the decision-maker in the process of selecting a small number of alternatives for more detailed design.…”

“…In particular, each design of interest is enumerated, and then run through the modules sequentially by a main loop, which stores the computed values for each design for subsequent exploration and analysis. 2 As evidenced by the lack of above-diagonal dependencies, the modules are carefully structured such that they can be executed sequentially without iteration or optimization loops. Eliminating feedback among modules is critical for achieving reasonable runtimes (of a few minutes for one potential system lifecycle of one architectural alternative) on current desktop computers.…”

“…2 To reflect the risk aversion associated with failing to meet emergency utility thresholds due to disturbances from the natural space environment, the reporting percentile for threshold availability is set at the 1 st percentile (i.e., 99% of the runs perform above the reported availability level). Given that utility losses within permissible thresholds are less severe, the reporting percentile for time-weighted average utility loss is set at the 95 th percentile (i.e., 95% of the runs experiences utility losses below the reported level and survivability, the clusters of points that form horizontal lines may be inferred to constitute the same baseline satellite radar architecture.…”

“…Survivability engineering is critical to minimizing the impact of disturbances (e.g., orbital debris, signal attenuation) to the operation of space systems, 2 and its importance is underscored by growing survivability concerns. 3,4 In this paper, Multi-Attribute Tradespace Exploration (MATE) for Survivability is introduced as a general methodology for the generation and assessment of alternative system architectures that must operate across disturbance environments.…”

Ensuring resilience and agility of complex organizational-technical systems

“…Principles of the architecture of resilient systems [12,[17][18][19][20][21][22][23][24][25][26][27] have been developed in order to endow new systems with the above attributes. Table 1 classifies and details some of these principles.…”