Rockets used to be hard. Really hard: they mostly blew up, especially when the various agencies were trying all sorts of weird and wonderful fuel / oxidiser com

Rockets used to be hard. Really hard: they mostly blew up, especially when the various agencies were trying all sorts of weird and wonderful fuel / oxidiser combinations in the search for the best possible specific impulse. See the book "Ignition!" by John D.Clark for some of the details. Interestingly, poking Google's ngram search suggests that whilst the phrase "rocket science" saw a little use around 1900 (I've no idea why: HG Wells?) and some use around the 1940s and 1960s, the phrase "not rocket science" is a far more recent coinage & only appears in the text corpus from the 90s onwards: http://books.google.com/ngrams/graph?content=not+rocket+science%2C+rocket+science&year_start=1800&year_end=2008&corpus=0&smoothing=2 http://books.google.com/ngrams/graph?content=not+rocket+scie...