Sis space stories for confident readers. Zack's family live in Moon Colony One. Zack's going to be and astronaut, just like his mum! READING HEROES is a series of graded storybooks with activities, created by reading experts.Sis space stories for confident readers. Zack's family live in Moon Colony One. Zack's going to be and astronaut, just like his mum! READING HEROES is a series of graded storybooks with activities, created by reading experts.