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Orbiter Autoland reliability analysisThe Space Shuttle Orbiter is the only space reentry vehicle in which the crew is seated upright. This position presents some physiological effects requiring countermeasures to prevent a crewmember from becoming incapacitated. This also introduces a potential need for automated vehicle landing capability. Autoland is a primary procedure that was identified as a requirement for landing following and extended duration orbiter mission. This report documents the results of the reliability analysis performed on the hardware required for an automated landing. A reliability block diagram was used to evaluate system reliability. The analysis considers the manual and automated landing modes currently available on the Orbiter. (Autoland is presently a backup system only.) Results of this study indicate a +/- 36 percent probability of successfully extending a nominal mission to 30 days. Enough variations were evaluated to verify that the reliability could be altered with missions planning and procedures. If the crew is modeled as being fully capable after 30 days, the probability of a successful manual landing is comparable to that of Autoland because much of the hardware is used for both manual and automated landing modes. The analysis indicates that the reliability for the manual mode is limited by the hardware and depends greatly on crew capability. Crew capability for a successful landing after 30 days has not been determined yet.
Document ID
19930013950
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Welch, D. Phillip (NASA Lyndon B. Johnson Space Center Houston, TX, United States)
Date Acquired
September 6, 2013
Publication Date
April 1, 1993
Subject Category
Spacecraft Design, Testing And Performance
Report/Patent Number
S-712
NASA-TM-4464
NAS 1.15:4464
Accession Number
93N23139
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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