Version 1.0.5 (vanilla), Win10Pro, 64 bit. (Apparently, from reading on reddit, this is something that happened in beta as well, but I would still consider it a bug ...) I built a colony on a moon, and after getting tired of meteors busting it up, went to the final story mission, and mined a bunch of the brain-blocks (takes forever, but do-able as long as it's not the blocks directly surrounding the final boss). I layered these outside my colony, and they definitely protected against meteors ... as long as I was on-screen. If I go down in the basement of my building, so that the ceiling is about one screen-height off the top of the screen, and a meteor swarm hits ... I usually come back upstairs to find that I've lost chunks out of my (lunar base block) ceiling and the upper parts of the walls. At first I thought that my brain-layer wasn't thick enough ... but after expanding it to have three buffered layers (i.e. 1 brain, 5 empty space, 1 brain, 5 empty space, 4 brain, inner wall) ... there's no way a meteor explosion carries for 16 blocks. :/ Meteors must be spawning *inside* my structure, to be causing this damage. Perhaps a check could be made to ensure that they don't spawn in anywhere that a placed background block exists?