It's not a difficult calculation but it's a ton of tedious arithmetic that references a metric buttload of physical property correlations and constants, most of which have no citation or pedigree. None of them are "interesting" enough to discuss in technical reports or academic papers but they are absolutely vital for defending and reproducing the work.

A big part of my code QA effort goes into finding these undocumented and hidden nuggets of joy and trying to reconstruct their pedigree so we have a good reason to believe our code output. It's hella tedious but it's fundamental science & engineering practice and absolutely necessary when dealing with safety significant code.

This is a reason I study software-related incidents and disasters - I'm paranoid of being the main character in a USCSB video, the voiceover part when Sheldon Smith says "... but analysts never verified their safety software was using the correct data." I never want Sheldon Smith to narrate any part of my life https://www.imdb.com/name/nm14185312/