> Why do you think NASA made the decision to use it?

Probably because they couldn't find low level programmers, it isn't easy to find people with good professional experience in C today, especially if you pay NASA wages.

This is certainly not the case. For more details do a little exploring in the link I provided above. For one, the bulk of their code is low-level, just not this particular system where it wouldn't have made sense; for two, they did this in 2002 when it was almost certainly easier to find C programmers than javascript programmers; for three, the people writing this javascript were domain experts, not professional programmers.

Some people would kill for the ability to put a 1/2-year NASA stint on the resume, if for no other reason than the idea that they contributed to the scientific research and exploration of space.

Javascript in those days was far slower and needed much more memory and power than native languages. Nothing in your link suggested otherwise.