A Methodology for Evaluating Technical Performance Parameter Design Margins to Control Earth and Space Science Instrument Cost.

摘要

Costs of aerospace missions have increased over the last twenty years, placing the future of the space program in jeopardy. A potential source for such growth can be attributed to the complex multidisciplinary and challenging nature of earth and space science instrument development. Design margins are additional resources carried in technical performance parameters to mitigate uncertainties throughout the product lifecycle. Margins are traditionally derived and allocated based upon historical experience intrinsic to organizations, as opposed to quantitative methods, jeopardizing the development of low-cost space-based instruments. This dissertation utilizes a methodology to evaluate the interrelationships between pre-launch and actual launch margins for the key technical performance parameters of mass, power, and data-rate to identify the extent to which excessive or insufficient margins are used in the design of space-based instruments in an effort to control instrument cost growth.;The research examined 62 space-based instruments from the National Aeronautics and Space Administration, Federally Funded Research and Development Centers, and universities. Statistical analysis consisting of paired t-tests and multiple linear regression were utilized to determine the degree to which space-based instruments are over or under designed by the use of excessive or insufficient design margins and to determine the effect of design margins for the technical performance parameters of mass, power, and data-rate on the percentage instrument cost growth from the preliminary design phase to launch.;Findings confirm, that in the implementation of space-based instruments, design margins are allocated to technical performance parameters above suggested government/industry standards, impacting the development of low-cost space-based instruments. The findings provide senior leadership, systems engineers, project managers, and resource managers with the ability to determine where opportunities exist to make trade-offs to reduce risk and to make informed decisions regarding achieving technical and programmatic requirements. The research forges a paradigm towards statistical analysis as a means to change existing design margin principles in an effort to reduce uncertainties in the design of the space-based instruments, improve the probability of the instruments performing to requirements, and to control cost growth.