Episode 9 tells us that 800 cycles (years) ago, a Catian and the first Assistaroid journeyed to Earth, hoping to sing the Insert Song from the anime Captain Future on the Earth's surface. Interesting factoid: Insert Songs, anime, TV, movies, radio, and phonographs were all invented less than 150 years ago!
Damn good episode, though.
She said she promised the captain she'd sing a song. She never said that he had a particular one in mind. She didn't pick the song until she heard it on her way to earth at the beginning of the episode
Why in god's name didn't Kio transfer leadership over to Eris? He has the freakin bell and if it's easy enough to transfer as the captain did for him it should only take 2 seconds to think, 'hey I don't want this (WHICH HE THINKS)' and go, 'here you take it' and hand it off to the only person in the room with experience in using it! It should be doubley obvious since Eris had previously given him her combat suit when she couldn't use it.
Then he would've had even less to do than he already does in the series (seriously, he can't do much because all the girls around him are ActionGirls. In-universe, Eris probably wouldn't think she could make the correct decisions, and probably couldn't of created the spaceship they'd need to get into space.