Delta-V

In 2032, billionaire Nathan Joyce is convinced that humanity's future depends on mining asteroids — and he has quietly built the ship to do it. Itinerant cave diver James Tighe wins a place among the crew after a brutal selection contest, then learns the true stakes: a multi-year expedition to the near-Earth asteroid Ryugu, no guaranteed fuel for the trip home, and a backer whose deceptions may strand them all in deep space. A hard-SF thriller about the first, desperate scramble to build an economy beyond Earth.