Ah this brings back memories of the good old days of analog computer lab for Controls I. There were integrators, differentiators, mixers and amplifier/attenuators.

From what I remember, it was good for seeing how a transfer function (differential equations converted and simplified to s-parameter polynomials) with or without feedback would perform based on the input function. The output was viewed on an oscilloscope.

I think the Mercury, Gemini and early Apollo spacecraft used analog computers, as well?