Spectral Representation of High‐Frequency Space Shuttle Data

High frequency Space Shuttle liftoff data are treated by autoregressive (AR) and autoregressive‐moving‐average (ARMA) digital algorithms. These algorithms provide useful information on the spectral densities of the data. Further, they yield spectral models, which lend themselves to incorporation into the concept of the random response spectrum. This concept yields a reasonably smooth power spectrum for the design of structural and mechanical systems when the available data bank is limited. Due to the nonstationarity of the liftoff event, the pertinent data are split into three slices. Each of the slices is associated with a rather distinguishable phase of the liftoff event, in which stationarity can be expected. The presented results are preliminary in nature; they aim to call attention to the availability of the discussed concepts and to the need to augment the Space Shuttle data bank as more flights are completed.