Where I work, we are strongly discouraged from ever using the cliché “rocket scientist.” There are no such people. Engineers, not scientists, design rockets. Rockets work by the application of physics, chemistry, and mathematics. The only true rocket scientist may have been Isaac Newton, who lived and died long before the first practical rockets were built. The distinction is an important one.
I am not going to waste time trying to convince people to be more accurate and stop using this term. It has passed into common English usage, to signify anything that is hard to do or understand. The phrase is usually expressed in the negative, as in “it doesn’t take a rocket scientist to do ‘x’,” where ‘x’ refers to something like, say, changing the oil in your car, or fixing the global economy.
Speaking of which… It turns out that the origin of this term may have a lot to do with the recent news from Wall Street. We turn back the clock to the 1980s, when young traders on Wall Street overturned the classical models of trading, with their quantitative, or “quant” modeling of options. It was a time well-chronicled in Tom Wolfe’s Bonfire of the Vanities, and Oliver Stone’s movie Wall Street. Armed with esoteric mathematical models, including one called the “Black-Scholes” equation, they were called by their elderly colleagues “rocket scientists.” At first the term was one of derision, later of envy. Their tool of choice was – surprise — the SUN workstation. SUN was a Silicon Valley start-up whose products were known for their innovations in architecture derived from a project at Stanford University (hence the name), and software from a computer scientist, not a rocket scientist, named Bill Joy. SUN developed the workstation for scientists and engineers, but the company thrived when it sold truckloads of them to Wall Street.
In 1984 Fischer Black, co-developer of the above-mentioned equation, moved from an academic post at the University of Chicago to Goldman Sachs in New York, and the era of rocket science began.It did not last that long, at least in its initial form. The crash of the stock market in the fall of 1987 was supposed to end all that. Apparently it didn’t. At least one news account is blaming the current crisis on Black and Scholes. No one is blaming SUN, which saw its innovations preempted by cheap Intel Pentium chips running Microsoft software. SUN went on to develop Java and a host of other innovations, but workstations don’t seem to generate much excitement any more. 
Perhaps in time we will get a fuller account of the causes of the current crisis. So far journalists are coming up with a new “real” cause per day. Looking for a silver lining in this cloud, perhaps the current crisis will cause people to think twice when they use the term “rocket scientist.” In any event, the next time you hear the term, don’t think of Wernher von Braun, think of Gordon Gekko, the character in the Oliver Stone movie.