Corrections: (1) The astrolabe was around since Hellenistic times, although the spherical astrolabe actually does date from the Middle Ages. (2) It seems likely that the spherical astrolabe was invented with input from "scientists" (natural philosophers).
Science is not particularly reliable.
And yet, we have remarkable technology, and can do medical marvels.
My tentative theory is that there's a lot of knowledge that's less formal than science in engineering, manufacturing, and the practice of medicine which makes it possible to get work done, and some fairly effective methods of filtering information that comes from science.