It’s hard sci-fi. Very similar to The Martian and Project Hail Mary, as in most of the things that happen are grounded in realism. For example, there is no “magic gravity”. People inside ships only experience “gravity” when the ship is under thrust. Or, if two ships are talking to each other long distance, they can’t talk in real time because of the time it takes for light to cross that distance.

The plot of the series is basically humankind has colonised Mars and the small asteroids and dwarf planets of the asteroid belt. Earth is massively populated, Mars is militaristic and united in its purpose to terraform Mars into a breathable planet, and the citizens of the asteroid belt are lower-class workers. It’s got the political plot lines of game of thrones.