I just find it very odd that the science grantmaking authorities are more willing to spend $$$ figuring out how to terraform Mars than how to stop desertification in the Sahara. Most of the technology that NASA comes up with does end up with some sort of massive Earthling benefit (satellites that currently run your cell phone and TV, for example), but if you asked the National Science Foundation for two million dollars to figure out how to solve, say, the issue of how to retrofit insulation into small areas where six inches of fluff is not feasible, you'd get nothing but an eyeroll. Yet when NASA needs to do the same to insulate a spaceship, they've got no problem unloading a dumptruck full of money for inventing Mylar.
There are lots of technologies invented for space that are quite useful on earth: refinements in freeze-drying, insulation, polymer technology, electronics, satellites that monitor our weather & geology and run our communications systems, water purification, spectroscopy, optical systems, waste disposal, closed ecological systems, reactor technology. All this stuff is great, we use it on earth all the time, but if you asked for a grant to work on it, forget it--the granting agencies only want to fund "basic research" because they feel that applications engineering somehow isn't "real science." Tell 'em you want to spend the $$ on ET, and somehow that's cool though. I don't get it.