Up until now, I think have I never seen a space in the Japanese textbook I'm using (Genki). However, when I started trying to read this まんが, I realised that, sometimes, there are spaces. Since this one is the very first I'm reading, I don't know if it's specific to this series, or happens normally. Anyway, I've attached a picture where this appears (last panel, on the left, between また and すげー).
Due to the lack of punctuation, I'm guessing this is a way of separating sentences, but I'm not sure. Another option that comes to mind is that it is used to facilitate the reading, like how they do it in children's books. Still, that shouldn't be applicable here (at the very least, this isn't supposed to be a book meant for children, I'd say). Could someone clarify this for me?