Τhe goal of CARIOQA-PHB is to define an initial concept for the Quantum Space Gravimetry Pathfinder mission, called CARIOQA, an experimental space mission aimed at testing and evaluating quantum gravimeter technology in space. The development of quantum sensors opens up new applications in climate science by improving the accuracy of gravity measurements from space. The use of this technology in space represents one of the most significant environmental, technological, and strategic challenges of the decade.