208 Appendix B. Appendixes: FT-MOEA E2 OR IE3 Primary failure pf IV3 to close after cutoff E3* Primary failure pf IV3 to close after cutoff E4 Primary failure pf K3 to open after cutoff OR Primary failure pf IV2 to close after cutoff E1 AND Thruster supplied with propellant after thrust cutoff G1 OR IE4 OR IE5 IE1 AND IE2 E8 Primary failure of S3 to open when commanded E5 Primary failure of K6 to open after timing out E6 Primary failure of K6 timer to time out E7 Operational failure of S3 to open when commanded Emergency switch S3 fails to open after cutoff EMF continues to be supplied to K3 after cutoff Primary failure of K6 to open after cutoff Primary failure to open after cutoff Primary failure to open of IV3 or K3 Inferred Monopropellant Propulsion System (MPPS) fault tree Figure B.2: Inferred Mono-propellant Propulsion System (MPPS) fault tree after applying FT-MOEA, source: NASA, 2002. B.4 Details of convergence of metrics over generations Figure B.4 depicts the convergence of the metrics ωs, ωd, andωc over the generations for the same example discussed in Figure 2.6 in Section 2.7.3. In this instance, the distribution within the population of each generation is also visualised. The aim is to provide a better understanding of the convergence of the metrics between generations. The common elements in these figures are grey shades associated with the percentiles 25% (darkest shade), 50%, 75%, and 100% (lightest shade), a horizontal blue line indicating the size of the ground truth FT, red dots representing
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