Initially I thought this book was going to be rather upbeat, but the mood goes on a downward spiral towards the end. Humanity loses interest in space exploration completely. In fact the only thing to still progress is the search for shallow consumer happiness. NASA decides to go for one last hurrah and sends a one way expedition to Titan. As the years pass during the voyage, the small crew gets increasingly on each others nerves while listening from afar as humanity fades away to oblivion back on earth. The novel is powerful and moving, with there is a glimmer of hope in the end when those among us most suited for it, the voyagers and explorers, get to carry on the seed of humanity. Life goes on despite short-sighted humanity.