Is the Earth too perfect? The Moon too grey? Mars too dusty? Then how about setting up a human colony in the depths of space?
Richard Hollingham travels to the Tennessee Valley Interstellar Workshop in Chattanooga, Tennessee to meet scientists, engineers, doctors and anthropologists planning human colonies in space and spaceships that will take humanity to the stars.
These are not dreamers - although they all have an ambitious dream - but well qualified experts. Several work at Nasa, others have day jobs at universities and research institutes.
Richard hears of proposals to build giant space stations and worldships - vessels packed with the best of humanity. These caravans in space might be lifeboats to escape an approaching asteroid or perhaps the first step to colonising the galaxy.