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Clarifying Objectives and Results of Equivalent System Mass Analyses for Advanced Life SupportThis paper discusses some of the analytical decisions that an investigator must make during the course of a life support system trade study. Equivalent System Mass (ESM) is often applied to evaluate trade study options in the Advanced Life Support (ALS) Program. ESM can be used to identify which of several options that meet all requirements are most likely to have lowest cost. It can also be used to identify which of the many interacting parts of a life support system have the greatest impact and sensitivity to assumptions. This paper summarizes recommendations made in the newly developed ALS ESM Guidelines Document and expands on some of the issues relating to trade studies that involve ESM. In particular, the following three points are expounded: 1) The importance of objectives: Analysis objectives drive the approach to any trade study, including identification of assumptions, selection of characteristics to compare in the analysis, and the most appropriate techniques for reflecting those characteristics. 2) The importance of results inferprefafion: The accuracy desired in the results depends upon the analysis objectives, whereas the realized accuracy is determined by the data quality and degree of detail in analysis methods. 3) The importance of analysis documentation: Documentation of assumptions and data modifications is critical for effective peer evaluation of any trade study. ESM results are analysis-specific and should always be reported in context, rather than as solitary values. For this reason, results reporting should be done with adequate rigor to allow for verification by other researchers.
Document ID
20040015101
Acquisition Source
Ames Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Levri, Julie A. (NASA Ames Research Center Moffett Field, CA, United States)
Drysdale, Alan E. (Boeing Co.)
Date Acquired
September 7, 2013
Publication Date
January 1, 2003
Subject Category
Man/System Technology And Life Support
Report/Patent Number
SAE-2003-01-2631
Meeting Information
Meeting: 33nd International Conference on Environmental Systems
Location: Vancouver, British Columbia
Country: Canada
Start Date: July 7, 2003
End Date: July 10, 2003
Sponsors: Society of Automotive Engineers, Inc.
Distribution Limits
Public
Copyright
Public Use Permitted.

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