What is the main conflict in Pale Blue Dot: A Vision of the Human Future in Space by Carl Sagan?

There is no conflict in a narrative sense. Many chapters of Pale Blue Dot focus on the geology of the planets in the Solar System, how to travel to Mars, the history of the Voyager probes, and so on. However, Sagan has a broader aim, for Pale Blue Dot is arguably a work of post-Christian Western theology. In fact, the book's subtitle is "A Vision of the Human Future in Space" and in fact, it is just that.