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Comparison Tools for Assessing the Microgravity Environment of Missions, Carriers and Conditions

Author:
McPherson, Kevin
Published:
Apr. 1997.
Physical Description:
1 electronic document
Additional Creators:
Moskowitz, Milton, DeLombard, Richard, and Hrovat, Ken
Online Version

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Summary:
The Principal Component Spectral Analysis and the Quasi-steady Three-dimensional Histogram techniques provide the means to describe the microgravity acceleration environment of an entire mission on a single plot. This allows a straight forward comparison of the microgravity environment between missions, carriers, and conditions. As shown in this report, the PCSA and QTH techniques bring both the range and median of the microgravity environment onto a single page for an entire mission or another time period or condition of interest. These single pages may then be used to compare similar analyses of other missions, time periods or conditions. The PCSA plot is based on the frequency distribution of the vibrational energy and is normally used for an acceleration data set containing frequencies above the lowest natural frequencies of the vehicle. The QTH plot is based on the direction and magnitude of the acceleration and is normally used for acceleration data sets with frequency content less than 0.1 Hz. Various operating conditions are made evident by using PCSA and QTH plots. Equipment operating either full or part time with sufficient magnitude to be considered a disturbance is very evident as well as equipment contributing to the background acceleration environment. A source's magnitude and/or frequency variability is also evident by the source's appearance on a PCSA plot. The PCSA and QTH techniques are valuable tools for extracting useful information from acceleration data taken over large spans of time. This report shows that these techniques provide a tool for comparison between different sets of microgravity acceleration data, for example different missions, different activities within a mission, and/or different attitudes within a mission. These techniques, as well as others, may be employed in order to derive useful information from acceleration data.
Other Subject(s):
Collection:
NASA Technical Reports Server (NTRS) Collection.
Note:
Document ID: 19970016980.
Accession ID: 97N19348.
NASA-TM-107446.
E-10719.
NAS 1.15:107446.
Terms of Use and Reproduction:
No Copyright.
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