Cost of Safety for Space Transportation

Paper number

IAC-06-D1.1.08

Author

Mr. Zachary Krevor, Georgia Institute of Technology, United States

Coauthor

Dr. Alan Wilhite, United States

Year

2006

Abstract

This paper proposes a methodology that determines the most cost effective way to meet space transportation reliability requirements.  This technique would be employed by design engineers to make decisions about a reliability approach.   The result is a minimum life cycle cost solution that satisfies vehicle reliability constraints.  These decisions will include the choice between developing more reliable hardware and using component redundancy.	

     There exists a need to determine the best way to fulfill reliability requirements.  The tradeoff between component redundancy and making parts more reliable has not been investigated.  Knowledge about the effects of redundancy on total life cycle cost is needed.  Additionally, there is little understood about the resources required to improve component reliability to acceptable levels.  System level reliability decisions are being made without a thorough exploration of cost saving opportunities.    

     The methodology in this paper will propose ways for achieving these cost possibilities.  The impact of using redundancy on a system, including how it affects metrics like turnaround time, development and operations cost, is presented.  The process of making parts more reliable is studied and quantified.  Techniques for improving component reliability are drawn from the aerospace industry and other industries that have stringent reliability requirements.  These procedures, along with the effects of using redundancy, form the basis of this methodology.  The process then uses system characteristics to determine both the resources required to satisfy reliability requirements and the effect on life cycle metrics of utilizing redundancy.    To incorporate the uncertainty that exists from specific applications, a stochastic approach is used. Case studies of historical space systems are presented to further demonstrate how this methodology is applicable.  The findings show how a different reliability approach would have resulted in significant cost reductions.  This process is then applied to future space systems to examine where cost saving choices can be made.  Conclusions are drawn about how to best meet reliability requirements while remaining within strict budgetary guidelines.  

Abstract document

IAC-06-D1.1.08.pdf

Manuscript document

IAC-06-D1.1.08.pdf (🔒 authorized access only).

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