 What would have happened if the Centaurus Expedition hadn’t failed?
"Our hopes were dashed—and I think all of us, even remembering the Centaurus Expedition's failure, hoped more than we cared to admit. If Procyon had possessed a habitable planet, we could have returned after an absence of not much over twenty years Earth time. If success comes there, a century will have passed before we can return to Earth; friends, relatives, all the generation that launched the Quest ships will be long since dead. It would be a one-way journey—even if enough fuel remained, there would be little point in returning to Earth after more than forty thousand years. Why not forget about Earth and go on to Omega Centauri?
 People from Earth would have colonized the Procyon system.
 People from Earth would have colonized the Procyon system.  Captain Llud would have become a hero.  The other two Quest ships would have been launched.  Humanity would have died out.