When space shuttle Atlantis rolled to a stop in 2011, it did not mark, as some worried, the end of human spaceflight. Rather, as the extinction of the dinosaurs allowed early mammals to flourish, retiring the shuttle signaled the opening of far grander opportunities for space exploration. Led by dozens of ambitious private companies, we are entering the early stages of the dispersal of Earth life into the solar system at large. The European Space Agency has revealed plans for a lunar habitat, and a Mars settlement is the stated goal of Elon Musk’s SpaceX company. The international research team Icarus Interstellar is taking this century to design propulsion technologies and great starships, ultimately to send an entire culture to a distant exoplanet. The human settlement of space is beginning now.