[code_biologist]

I suspect that phrase may be a oblique reference to the absolutely lovely UI testing book "Rocket Surgery Made Easy: The Do-It-Yourself Guide to Finding and Fixing Usability Problems" by Steve Krug.

[stavros]

We've been using "rocket surgery" as a portmanteau of "rocket science" and "brain surgery" for decades, though.

[almostnormal]

The use of that mixture of rocket science and brain surgery predates that book from 2009 by at least 15 years.

[EasyMark]

The first time I heard it was on "trailer park boys" as a "Rickyism" so I suspect it would sneak into more people's vocabulary that way. No idea which came first.