Key to the story's premise is the fact a jettisoned heat shield melts it's way through the ice, thus creating a channel to the liquid surface beneath the crust. Through various exploritory manuvers, the crater becomes a cauldron in which dormant life forms emerge.
"Fornax" is the name of the ship the team has built to explore an ice moon in a system in the constellation Fornax. It consists of four separate units: the orbiter, the base of the ship; the lander, which detaches and penetrates the moon's atmosphere, which carries the drone and the rover, for exploring the surface. We also see Marco's interface readouts.