I fully expect Ranka's single "Interstellar Flight" to be sung during Ranka's Live performance that will be shown in a future episode. It was talked about in Ep 11 so I would expect it to happen pretty soon.
BTW do you think her live concert performance in the series when she sings Interstellar Flight will show her doing the same moves from the promotional dance routine special? (
YouTube Link)
Thank you very much for the link to that .ogg of Cat Diary. +1