Space shuttle operation requires the monitoring of a large number of stationary signals in the search for "anomalies." This problem amounts to determining whether a change has occurred in a signal having a partially known structure. We employ empirical methods based on type theory to tackle this problem. We show that through pre-processing of the signal and through modifications in the type method itself, certain types of changes can be detected. The probability of detection, and probability of false alarm are determined by the amount of training data and a threshold, both of which are under user control.