Starclimber is the third book in the Matt Cruse fantasy series, written by Canadian author Kenneth Oppel.
Matt Cruse is piloting an aerocrane for France's Celestial Tower where he narrowly survives a terrorist attack by the Babelites, a group of people who are opposed to humans reaching the heavens.
Canada's Minister of Air wants Canadians to be the first in space, and invites Kate to join the expedition as an expert in aerial zoology, while Matt is offered a chance to become one of the world's first astronauts on board the Starclimber.
The next morning, Captain Walken tells him that one of the men they chose broke his leg, and offers Matt a spot on the space trip as a replacement.
When he does, Kate attempts to change the subject, only to provoke Matt into claiming that she is lying to him about breaking off her engagement with James Sanderson.
The remaining members of Starclimber are left in orbit around the earth when Matt develops a crude but brilliant brainstorm using an emergency oxygen tank as a propellant and using the toilets' flush mechanisms as maneuvering jets, giving the crew only one chance to reenter the atmosphere.
The beginning launch is successful, but Captain Walken is knocked unconscious, and Matt and Tobias are left as the only members of Starclimber's crew who are able to pilot her.