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For Choose Your Own Adventure books, try the article List of Choose Your Own Adventure Books at The Other Wiki. A couple were set in space, but I don't remember the specific elements you mention.
Your Greek myths comic wouldn't happen to be this 'Greek Myths for Young Children' book, would it? http://www.amazon.com/exec/obidos/ASIN/1564024407/historyforkids
I had it as a kid (in fact, it's probably still at my parents' place) and it seems to match your description.

Let's see, I remember erading this book in my Middle School years, from the very late 90's to the early 00's. It was a Choose Your Own Adventure book the library had, and I read it to death. It had the main character in space for some reason, and I remember parts of it talking about other forms of lifeforms not carbon based, and your blood boiling off if you chose to go to Venus and landing near its equator.
The other was a Greek based myth comic on Heracles my school's history book had. It was crudely drawn, with some fairly realistic peach colors for the humans, and I remember blue for Heracles' family after Hera ordered to slay them (you know why.) It was fairly detailed to the point of being kind of gory, while keeping all the drawings very simplistic and rough. It implied it was from a larger collection of comics, and I've been meaning to look it up for some time.
And it covered the entire tasks of Heracles, usually devoting 3-10 panels a task.
Edited by Asuyuka