it's been awhile, but i'm almost positive that it is used in the Zeta series. in fact, i am sure of it, but I don't recall what episode it's in... And I do seem to remember it being blue... your best bet is to try the third Zeta Gundam compilation movie. They have changed things from the original, but it's sure to be in there, and it's alot better than going and trying random episodes of the original series to find it.