## 6 Conclusions  
Launch vehicles are very complex systems that often require equally complex systems engineering approaches to design, build, test, and launch them. Diverse systems engineering approaches can be implemented in different ways. Regardless of the systems engineering style or model, this study identified factors that affect systems engineering process performance in launch vehicle organizations. Deficient or low performing systems engineering has been identified in several studies as a leading contributor to launch vehicle failures. Given the significant influence of launch vehicle failures on human life, the economy, science, and national security, identifying factors that could enhance systems engineering process performance in launch vehicle organizations is imperative. A systems engineering process performance model was developed to examine the relationships among perceived top management support, organizational commitment, the value of systems engineering, systems engineering support, and systems engineering process performance in US launch vehicle organizations. SEM and hypothesis testing results showed that organizational commitment, the value of systems engineering, and systems engineering support directly or indirectly influence systems engineering process performance. While top management support indirectly influence systems engineering process performance. The data set for this study was provided voluntarily from participants in US launch vehicle organizations. Survey responses that assessed the latent variables of this study are based on participant's perceptions. Responses may have been based on what participants believe is ideal and not what was observed or experienced in respective organizations. The survey also did not take in to account risk tolerance of the individual organizations. A difference in risk tolerance could potentially lead to different perceptions of the systems engineering process. Despite these limitations, the results of this study identified factors that present implications for systems engineering and U.S. launch vehicle organizations. Past research has shown that systems engineering significantly impacts technical performance, cost, and schedule [7; 9; 10; 19; 20; 21; 22; 24; 41]. Prior research has also identified deficiencies in the systems engineering process as a major contributor to launch vehicle failures [6; 16; 17; 18]. Improving the factors that affect systems engineering process performance could improve technical performance of the system, reduce cost, improve schedule, and reduce the number of launch vehicle failures. This study's results underscore the important roles of organizational factors in systems engineering process performance. Organizational leaders should emphasize their support for systems engineering, highlight the value of systems engineering, enhance systems engineering support, and bolster employee commitment to organizations. Improving on these factors may increase the ability of organizations to meet cost, schedule, technical performance, and customer satisfaction goals, thus ultimately improving launch vehicle success. Conceptualization, D.G., W.K. and T.K. ; methodology, D.G. ; software, D.G. ; validation, D.G. ; formal analysis, D.G. ; investigation, D.G. ; resources, D.G. ; data curation, D.G. ; writing--original draft preparation, D.G. ; writing--review and editing, D.G. and W.K. ; visualization, D.G. ; supervision, W.K., T.K., L.R. and D.K. ; project administration, D.G. All authors have read and agreed to the published version of the manuscript. This research received no external funding. The study was determined to be exempt human research and approved by the Institutional Review Board of University of Central Florida (SBE-18-14051, 30 May 2018). Exempt status was granted since participation in the survey was completely voluntary, working adults in the launch vehicle industry was the target population, and survey statements were about the organization of employment. The authors declare no conflict of interest.