Books in the 8-10 series series

Azalin's class go on a school trip to another planet.The planet Earth.Once on Earth, Azalin runs away.Her dream is to be a 'tronic when she grows up: one of the special people who maintain the systems keeping the man-made planet of Newarth alive.But just before leaving for Earth, she was told that Newarth already has all the 'tronics it needs. She will have to be a store-keeper instead. And she is to be 'sporting' about it.Azalin doesn't want to be a store-keeper. And she doesn't want to be sporting.So she runs away. She phones home to say that when she's allowed to be a 'tronic, she'll come back. But, alone on Earth, Azalin has no idea how much danger she's in. Life on Earth isn't as safe and ordered as life on Newarth.Especially when she wanders into the 'no-go' zone called 'The Rookery.'Even the Earth Police won't go there... Azalin comes down to Earth. But will she survive to home to Newarth?