The Differential Analyzer is used to calculate the trajectory of the moon rocket.
Just a couple of seconds of stock footage here.
Year of feature (shown above)
This scene is actually from This Island Earth(1951) and not Destination Moon.. It's a differential analyser mechanical computer.
It should be noted that differential analyzers had an upper limit of accuracy of about 2 or 3 digits. Predictions of the position of planets and other work in celestial mechanics was worked out to on the order 5 or 6 digits of accuracy, as result differential analyzers were ill equipped to do work in this area. So it is not strictly realistic to use a differential analyzer for a rocket trajectory. In this case you could miss the Moon by thousands, or tens of thousands, of kilometers. Whereas Lunar theory circa 1950 done using digital calculations would yield an accurate lunar with errors of a few kilometers. This same criticism holds for the use of the Differential Analyzer in When Worlds Collide (1951).
why am i on this site