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Independent Orbiter Assessment (IOA): Analysis of the instrumentation subsystemThe results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The independent analysis results for the Instrumentation Subsystem are documented. The Instrumentation Subsystem (SS) consists of transducers, signal conditioning equipment, pulse code modulation (PCM) encoding equipment, tape recorders, frequency division multiplexers, and timing equipment. For this analysis, the SS is broken into two major groupings: Operational Instrumentation (OI) equipment and Modular Auxiliary Data System (MADS) equipment. The OI equipment is required to acquire, condition, scale, digitize, interleave/multiplex, format, and distribute operational Orbiter and payload data and voice for display, recording, telemetry, and checkout. It also must provide accurate timing for time critical functions for crew and payload specialist use. The MADS provides additional instrumentation to measure and record selected pressure, temperature, strain, vibration, and event data for post-flight playback and analysis. MADS data is used to assess vehicle responses to the flight environment and to permit correlation of such data from flight to flight. The IOA analysis utilized available SS hardware drawings and schematics for identifying hardware assemblies and components and their interfaces. Criticality for each item was assigned on the basis of the worst-case effect of the failure modes identified.
Document ID
19900001612
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Howard, B. S.
(McDonnell-Douglas Corp. Houston, TX, United States)
Date Acquired
September 6, 2013
Publication Date
December 12, 1986
Subject Category
Space Transportation
Report/Patent Number
NAS 1.26:185571
REPT-1.0-WP-VA86001-17
NASA-CR-185571
Accession Number
90N10928
Funding Number(s)
CONTRACT_GRANT: NAS9-17650
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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