Larklight: a rousing tale of dauntless pluck in the farthest reaches of space, by Philip Reeve.  Illustrations by David Wyatt.

#1 Art and Myrtle series

#2 Starcross

This award winning book for girls, grades 6-10, is a wildly imaginative sci-fi pirate adventure with tongue-in-cheek humour, social commentary on accepting those who are different, giant spiders, and floating houses in space.  Myrtle Mumsby and her brother live with their father in a huge house called Larklight, which just happens to be traveling through outer space. Soon the kids are off on an adventure, where they will do battle with evil forces in order to save each other and the universe.  Can they survive the changeling Trees of Venus and their poisonous pollen?  What's that idiom again that describes being rescued from giant spiders by a notorious pirate? 

Citation: Reeve, Philip. Larklight: a rousing tale of dauntless pluck in the farthest reaches of space. New York: Bloomsbury, 2006.