Pure BS. The main problem with making optics for telescopes, and especially for large and/or space telescopes is precision. It is hard enough to grind somethi

Pure BS. The main problem with making optics for telescopes, and especially for large and/or space telescopes is precision. It is hard enough to grind something to a precise shape when that shape is a smooth surface. Forget about making precise fresnel lens that has extremely complex shape that relies on very precise smooth surfaces right next to very sharp discontinuities, that is not going to happen. Another problem is that you don't really ever want lenses for a high power telescope. Lenses cause optical aberration -- and once light rays of different colors go each their own way it is pretty much impossible to put them back precisely enough for the kind of telescope you would want to shoot into space. The article sounds like a third grader got interested in astronomy and suddenly discovered fresnel. Do you think NASA somehow overlooked an obvious solution to all their problems that has been known for hundreds of years to everybody else?