Thoughts Partially Related To A Movie

by Don Friedman on January 10, 2017

“An Engineer’s Office”…after they told him to clean it up for the camera:

Hidden Figures is a good and enjoyable movie. The overall story is true; I would assume that large amounts of the detail shown are fiction, created to make reality into a two-hour story.

Since the three women who are the central characters were “calculators” – i.e., practical mathematicians – employed at NASA, there is a fair amount of discussion of math and science. The creation and launching of rockets are, of course, acts of engineering, rather than science. (To be fair to the script, one of the three main characters ends up becoming an engineer.) Engineering is not without an admixture of math, although it’s easily possible in our field to go months without performing any calculations more complex than advanced algebra.

The vast majority of engineering analysis and design concerns problems of some known type. Since the idea is to create a useful outcome rather than, as in science, to explore new ideas, problems of a known type are welcomed, since they are easy to solve. The math behind, for example, solving for the stresses and deflections in a beam goes back hundreds of years. I have no desire to re-solve those problems and I don’t have to because we have references where they are solved. People sometimes complain about engineers using software that hides design inside a black box, but before those programs existed engineers used written black-box equations.

The movie rightly emphasizes that the problems to be solved for human-created orbital mechanics were new, although the word “math” is used rather than “problems.” These were not problems of a known type, which made solving them far more difficult in 1961 than it is today.

We use the word “modeling” a lot. It describes using elaborate computer programs to review entire building frames and it describes simplish equations that describe beams. When faced with a problem that is not of a known type, modeling is often the tool used to turn it into something known and therefore more easily solved. For example, the cantilever method of frame analysis, which was heavily used before electronic calculators and computers were available, modeled entire buildings as cantilever beams stuck in the ground. That’s a pretty crude model, but the relatively simple calculations that follow from it were used to design the structure of the great skyscrapers of the 1920s and 30s. I can’t speak for NASA and orbital calculations, but for structural design, having a model that makes sense is more important than having one that is beautifully precise.

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