Most of the "hard-core" stuff at various NASA labs is done in Fortran -- it's very popular for numerical processing among physicists and astronomers, and there are huge libraries available for it. However, Larry Wall has worked at JPL in the past, so I presume some of his code (and his legacy!) is still floating around. As a matter of fact, this page from JPL about Numerical processing resources has links to some Fortran pre-processors in Perl¹, which presumably someone over there is using.

As for other uses, how about saving the Human Genome project?

¹Sounds really weird to me... ;-)