After the first 8 books in The Grand Tour (Mars in particular), Jupiter feels a bit odd at the start. We’re not building up to the eventual discovery of life–the fact that there’s life on Jupiter is presented fait accompli in the first chapters. And not only life… intelligent life (or so is claimed). Jupiter isn’t really about the discovery of life or even really about the idea of life on a research station around Jupiter.
What Jupiter is really about the conflict between religion and science as humanity continues to expand outwards into the solar system. The New Morality controls the politics of the Earth and is doing everything it can to control the solar system. In doing so, they send Grant Archer–a believer and an astrophysicist–to spy on what in the world is going on far out in the dark reaches of the solar system. There’s conflict between science and religion, both on the large scale with the New Morality and the small scale within Grant himself, especially as he begins to settle in and befriend those living on Jupiter station.