PYRA AND THE TEKTITES: AQUARIUM IN SPACE by Tyree Campbell

Pyra, age thirteen, is running away from home in the Asteroid Belt because she’s not doing well in school. Her parents want to send her to Mars for school, and she doesn’t want to go. She sneaks aboard a cargo shuttle, and falls asleep in the hold. When she awakens, she finds herself in free-fall; the shuttle has been seized by the Tektites, a group of rebel pirates . . .
 
. . . and the adventures begin!