NASA folks are very meticulous about making sure that what they spend dollars on will do the intended job. Could be that their criteria aren't the same as the typical consumer or even the Earth-bound professional photographer. When you're spending thousands of dollars per pound to get people and equipment into orbit, the purchase cost of the gear is only one factor in selection.
For example, here are two factors that go into selecting equipment for space - 1) resistance to radiation (gamma rays, alpha particles, heavy ions in solar wind, tolerance to accumlate dose, etc.) and 2) how the equipment behaves in the ultra-harsh environments (shock, vibration, temperature extremes, lack of humidity, lack of atmospheric pressure, etc.).
Most of us don't have these at the top of our list as to what we look for in a camera and accessories.