You may not be able to do the kinds of science that will test the hypotheses you want to evaluate. We could build a lot of Zero Gradient Synchrotrons for what the Large Hadron Collider cost, but the ZGS isn't anywhere close to being powerful enough to measure the properties of the Higgs boson. Another example: For less than USD 500 an individual may outfit themselves with an optical telescope more accurate, more precise, and more powerful than anything available to Galileo or Kepler or Newton, but such a "cheap and repeatable" device will never be capable of sensing the gravitational waves detected by the LIGO and Virgo laser interferometers. Also, that $500 Celestron is only possible because of all of the one-off telescopes that came before it. You have to start somewhere, and NASA is that somewhere for space science.
