Hi, VerZakes
I collect several topics and I know it is very hard to organize them.
My "monkeys on stamps" collection is organized by taxonomic organization although very general: Prosimians (Lemurs and others), New world monkeys (America), Old world monkeys (Asia and Africa) and Primates: Gorilla, Chimp, Orangutan etc. Besides, I have separate stock books for monkeys in science, monkeys in art, monkeys in cinema, in literature, Chinese Year of the monkey, Chinese novel monkey king, Ramayana Hindu epic etc.
More hard to organize is my "Mythologies of the world" stamp collection. I created album pages for subjects that I have several stamps or sets. But I have many I can't create pages and they are still kept in stock books.
Here are several album pages:




I believe it is possible to organize Space stamps in that way too, at least these stamps with common subjects like Apollo-Soyuz mission or first man on the moon. Sure you will left with many stamps that have no common with other stamps.