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Heroic Reliability Improvement in Manned Space SystemsSystem reliability can be significantly improved by a strong continued effort to identify and remove all the causes of actual failures. Newly designed systems often have unexpected high failure rates which can be reduced by successive design improvements until the final operational system has an acceptable failure rate. There are many causes of failures and many ways to remove them. New systems may have poor specifications, design errors, or mistaken operations concepts. Correcting unexpected problems as they occur can produce large early gains in reliability. Improved technology in materials, components, and design approaches can increase reliability. The reliability growth is achieved by repeatedly operating the system until it fails, identifying the failure cause, and fixing the problem. The failure rate reduction that can be obtained depends on the number and the failure rates of the correctable failures. Under the strong assumption that the failure causes can be removed, the decline in overall failure rate can be predicted. If a failure occurs at the rate of lambda per unit time, the expected time before the failure occurs and can be corrected is 1/lambda, the Mean Time Before Failure (MTBF). Finding and fixing a less frequent failure with the rate of lambda/2 per unit time requires twice as long, time of 1/(2 lambda). Cutting the failure rate in half requires doubling the test and redesign time and finding and eliminating the failure causes.Reducing the failure rate significantly requires a heroic reliability improvement effort.
Document ID
20170010349
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Jones, Harry W. (NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
October 27, 2017
Publication Date
July 16, 2017
Subject Category
Quality Assurance And Reliability
Report/Patent Number
ICES-2017-86
ARC-E-DAA-TN43290
ARC-E-DAA-TN41126
Meeting Information
Meeting: International Conference on Environmental Systems
Location: Charleston, SC
Country: United States
Start Date: July 16, 2017
End Date: July 20, 2017
Sponsors: International Conference On Environmental Systems, Inc.
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Keywords
life support
reliability

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