Mark Powers 
Space Detectives [PDF ebook] 

»Immensely, cheerily silly» Guardian
Dog lost in space? Grown an extra head and don»t know why? Pocket money stolen by a green blob? You need the Space Detectives!
Connor and Ethan are spending their summer holidays aboard the world»s first orbiting city, Starville (basically Beverley Hills in space!). The amazing space station is bursting with celebrities and the mega-rich. But Connor and Ethan are too busy selling ice cream to see the sights.
However, neither of our heroes can resist a mystery and when they discover the space station is hurtling on a collision course with the moon (eep!) they know they need to step in. This is a case for the SPACE DETECTIVES!
Can Connor and Ethan find the culprit and save Starville from its impending doom?
LOOK OUT FOR SPACE DETECTIVES: EXTRA WEIRD CREATURES