A lot of books can be classified as "science fiction," so here is a list of Teen Fiction titles for those who like their sci-fi set in outer space.

Academy 7 by Anne Osterlund, 2009
Aerin, a fugitive former slave, has earned a place at Academy 7, the most exclusive military school in the universe, where she finds herself in fierce competition with Dane, the son of a powerful general. Little do they know that they each hold a key to information that could cause political repercussions throughout the Alliance.

Across the Universe by Beth Revis, 2011
Amy has joined her parents as frozen cargo aboard the spaceship Godspeed, where they will re-awaken three hundred years in the future on their new home planet. But Amy is unfrozen 50 years too soon in what looks to be the first in a string of attempted murders of the frozen colonists.

Black Hole Sun by David Macinnis Gill, 2010
Durango is a Regulator living on a colonized and terraformed Mars and takes jobs that most others would refuse. His newest job? Protecting a group of miners from the cannibalistic monstrosities called DrEu.

A Confusion of Princes by Garth Nix, 2012
Taken as a child and equipped with biological and technological improvements, Khemri has been trained and prepared for the glory of becoming Prince of the Empire. But after graduating into full Princehood, he learns the terrible truth: there are ten million princes, and all of them want each other dead.

Ender's Game by Orson Scott Card, 1991
An alien race known as “buggers” have invaded Earth twice. A third invasion is feared and a new commander is sought. Ender Wiggin is only six years old when he is sent to the space station Battle School. By the age of 12, he has learned the art of command and earned the respect and fear of his fellow soldiers. But is Ender the commander Earth needs?

The Knife of Never Letting Go by Patrick Ness, 2008
Todd grew up believing that the Spackle released a germ that killed all the women and unleashed Noise on the remaining men. After discovering a patch of silence, his adopted parents tell him that he has to run, leaving him with only a map, a message and many unanswered questions. As he travels, he soon discovers the source of the silence: a girl named Viola.

Losers in Space by John Barnes, 2012
In a future where everyone is rich and no one is hungry, there’s only one downside: there's nothing to do. So why not stow away on a spaceship to Mars with other so-called losers to increase your profile? Maybe because the ringleader might be an actual sociopath? And there are a lot of ways to earn notoriety…

The Obsidian Blade by Pete Hautman, 2012
Tucker's father had already disappeared once before, when he climbed on the roof to fix a shingle and vanished – only to walk up the driveway an hour later, looking older and with a strange girl in tow. But now both of his parents have disappeared and Tucker is beginning to suspect that the shimmering disks he keeps seeing may hold the answer. So he steps into one… and is wormholed through time and space.

Skyship Academy: The Pearl Wars by Nick James, 2011
The year is 2095 and Jesse is a Skyship Academy student, secretly trained to help residents of Skyship, a nation of vessels hovering over a ruined America, gather the Pearls (a coveted source of energy) that fall from the sky.

Starglass by Phoebe North, 2013
Terra has never known anything but life aboard the Asherah, a city-within-a-spaceship that left Earth five hundred years ago in search of refuge. As they approach the chosen planet, she inadvertently witnesses the captain's guard murdering an innocent man and is thrust into the dark world beneath her ship's idyllic surface.