Gerard Holzmann (http://spinroot.com/gerard/) came to JPL from Bell Labs in 2003, and the period since he arrived has coincided with a time of greater prominence for methodologies of producing reliable software. Although many people contributed to the document in this post (see page 5), Gerard was the driving force behind drafting it and getting buy-in from the people who write flight software. The latter part -- cultural -- is as big a challenge as the technical stuff.

Another thing that happened around this time is getting licensing for Coverity and other tools, and introduction and promotion of static code verification, even for non-flight software.

Here's an interview with Gerard:

http://spinroot.com/gerard/Caltech_Engenious.pdf