The company I worked for did work for NASA and we got lot of applicants. However, HR gave the hiring managers a list of the top 20 engineering schools and told us to favor those grads, especially the top 5 schools. HR never said which schools got a premium, but I suspect it was those top 5. I would guess it was on the order of 5%.
Raises were pretty good in those days, so a good performing new grad from the “lesser” schools could easily be making more money than a poorly performing MIT grad in a year or two.