The Cassini Code

Galahad is a starship carrying a crew of teenagers, sent away from Earth after a comet's tail leaves deadly particles behind and a plague wipes out the adult population. The mission is humanity's last hope, and the young crew has already survived a first encounter with an alien race. Now the ship must cross the Kuiper Belt, a dangerous field of asteroids on the edge of the solar system. Triana and her Council must keep the ship on course while a restless faction led by Merit pushes for a return to Earth. As the crew grows hostile and some councillors start to listen, Triana has to find a way to stop a mutiny and keep everyone alive.