I know a bona-fide ex-NASA rocket scientist who uses Matlab. He finds that it's much more productive than C, which he used to use heavily. His NASA job basically involved numerical methods for integration to track the trajectory of the Space Shuttle.
I like MatLab, but for me (biologist) it's a very intricate language to learn, and AFAIK not easy to use in multiple platforms where you don't have the framework installed. And "expensive" too (as Mathematica).
But as a rocket scientist, he says there is a lot of software ready-made for him to use, which even included graphics/animation, analysis of realtime data feeds, and limited finite-element analysis of the rocket's structure. Also, his boss had a good software budget at the time.