The Long Mars by Terry Pratchett

In a universe where countless parallel Earths exist, humanity continues its exploration of these alternate worlds, driven by the discovery of the Long Earth. As the journey extends beyond Earth, a new frontier emerges with the Long Mars, a series of parallel Mars planets. The narrative follows the adventures of Joshua Valienté and Sally Linsay as they navigate the challenges of interplanetary exploration, confront enigmatic alien life forms, and grapple with the implications of humanity's expansion across the cosmos. Amidst the backdrop of scientific discovery and existential questions, the story delves into themes of identity, evolution, and the boundless potential of human ingenuity.