Starman's Quest by Robert Silverberg

StarMan's Quest is a science fiction novel written by Robert Silverberg. The novel is set in the 37th Century and the Earth is an overcrowded place with high unemployment and enforced consumerism.

In order to preserve the jobs of others, everyone is encouraged to spend everything they have or earn, saving money is severly frowned upon. Intersteller travel is a reality but an expensive one, only the lucky few can ever hope to escape the overcrowded confines of Earth.

Alan Donnell is the son of a spaceship captain and Alan is determined to unravel the mystery of the space-time problem. Time aboard the Starships is different to that of earth, a 6 week trip to Alpha Centuri means that when they get back to earth 9 years have passed.

For this reason it has become a custom for Space families to remain on the ships, living their entire lives in the confines of the ship. Alans twin brother jumps ship to take the chance on earth, by the time the two meet up once more, Steve is 26 and Alan still only seventeen.