The Galileo Spacecraft Modal Survey had some unique and demanding data-acquisition and data-analysis requirements. A variety of excitation and analysis techniques were used. Most of the command-generation, data-acquisition, and data-analysis tasks were performed with the Wyle Modal Analysis and Test System (MATS). This paper describes the data acquisition and analysis aspects of this multiapproach test program. The purpose and objectives of the Modal Survey, as well as the technical approach, are discussed. Hardware and software features are described including developments which were accomplished in preparation for the Modal Survey. The primary test method was the classical tuned-multiexciter sinusoidal dwell. Special software was developed to expedite use of that technique. In addition, software was provided for the measurement and analysis of responses to random and chirp (fast sine sweep) excitations. Frequency response functions were computed in real time using the SWIFT technique during single-exciter and multiexciter sinusoidal sweeps. Modal analysis was accomplished by curve-fitting in the frequency domain, by frequency-domain eigensolution, and by time-domain eigensolution. MATS was used for on-line analysis of modal-test results. These analyses included orthogonality of analytical and measured mode shapes. Effective-mass and residual-mass calculations were also performed on-line.
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