According to a paper written by Northeastern University, NASA has a 10:1 return rate on their spending, however some sites range it from 4:1 to 14:1. NASA currently employs 18,000 people, many of whom are scientists, engineers, and government contractors.
NASA also will make inventions that have real marketplace value that results in many more jobs and economic benefits. One key example is Tempur-pedic mattresses. The material of the mattresses were originally put into aircraft seats to try and increase the survivability rates in case of major crashes.