The Silver Six

"When a group of orphans discover they have a common connection, plucky heroine Phoebe leads them in a daring escape from their orphanage to an uninhabited moon. But their idyllic paradise is shattered when the powerful corporate boss who caused the deaths of their parents sends a relentless henchman to track them down. Now, with nowhere left to turn and tired of being on the run, these resourceful kids decide there's only one thing left to do: Fight back!"--Publisher's web site.