Heaven in the Stars

Although the novel takes place entirely on Earth and doesn't feature any of the typical tropes of science fiction, the idea of interstellar travel is one frequently brought up from the start of the novel, when it is mentioned that presidential candidate Christopher Donner plans to end the American space program. This goes directly in conflict with the wishes Lauren has for the human race, which is that they will find heaven by leaving the ravaged Earth and colonizing other planets. 

Lauren also brings up that a space probe funded by the British and Japanese has found yet another possibly habitable planet. This contrasts with the United States, which has been trying to get rid of its space program as it slowly descends into further anarchy and violence. The space program serves as a representation of progress and stability in a country, and is used to signify that the United States is falling behind. 

Once again, the theme of certainty and uncertainty ties into this. Lauren dreams of interstellar travel and sees it as a better alternative to the Christian idea of a heaven, which is not as tangible and is only something people can hope exists after they die. Nobody can be certain that the spiritual heaven actually exists. However, even though the extrasolar planets are a tangible concept of a "heaven," Lauren doesn't see that there is still some degree of uncertainty. What if disaster happens on the long spaceship ride to the new planet? What if the temperatures are habitable, but the soil and air cannot support life? How will an initially small group of people form a new society and survive billions of miles from home? 

Maybe Lauren is just willing to accept these uncertainties, as the central principle of her religion is the inevitability of change. At some point, colonizing the stars will have to take place.