Welcome.
My questions:
1. Are you sure you need all those files? To reduce loading time, keep only the files you are customizing. (not sure, I'm just asking)
2. Your resource pack works only if I extract it. This is not the standard way. Instead of: Galacticraft (16x16).zip\Galacticraft (16x16)\{assets + pack.mcmeta + pack.png}\ and so on, do this instead: Galacticraft (16x16).zip\{assets + pack.mcmeta + pack.png}\ and so on. Minecraft tries to find the pack.mcmeta only in the 1st directory level, never in the directories downwards.
3. What GC version is this for? Put it in the OP. GC4 (1.8.9+) uses a totally file naming system; this pack may not load.