Barbary — Vonda N. McIntyre

A story of feline first contact by the Hugo and Nebula Award�"winning author that “recalls Robert Heinlein's excellent stories for this age group” (Publishers Weekly).
 
Twelve-year-old Barbary has been dreaming of going to space for as long as she can remember. Now, the orphan is on her way, joining the family of her mother's best friend on the research station Einstein -- but she won't be going alone. Barbary can't bear to leave behind her only friend, a Manx tabby cat named Mickey.
 
Getting used to zero gravity is just one challenge the pair will face on their journey; when they finally land on Einstein, Barbary will have to trust her new sister with her secret stowaway. But Mickey's mischievous nature may get Barbary kicked off of her new home for good -- and put all of humanity at risk as an alien ship flies their way . . .
 
“Excitement about space, living on a frontier, and . . . down-to-earth mechanical details . . . McIntyre displays the talent that won her acclaim.” -- Publishers Weekly
 
“Engrossing. A lot of physics and engineering are woven unobtrusively into the book. Good for buffs and newcomers.” -- Kirkus Reviews