Ok I'm really annoyed. I got the yellow and green huge materia but was unable to get the huge materia sent into space. But then (being on the 3rd disc now) I found underwater, the red huge materia. But when I went to Cosmo Canyon, it was too late because Bugenhagen had already left and given Red XIII his ultimate weapon, etc etc. I went up to look at all my huge materia (there were 3, red, yellow and green) by myself but when I looked at them closely, it just described how it's a summon materia or whatever.
Does this mean being able to get the huge materia underwater is completely useless anyway?