FEATS-G will quantify the potential of a future quantum space gravimetry (QSG) mission by detailed simulation experiments for various real-world applications related to the monitoring of underground changes over time, e.g., geophysics, climate research, and Earth sciences in general. By bringing together researchers from 13 European and 7 Japanese institutions as well as experts in space mission design, geodetic gravity field processing, and numerous application areas, we will quantify and illustrate the added value of novel QSG mission concepts based on either gravimetry and gradiometry configurations over already existing (GRACE/-FO) or firmly planned gravity satellite constellations (GRACE-C and NGGM/MAGIC). By building on the latest sensor specifications from CARIOQA and other industry-lead research activities, we will perform detailed end-to-end satellite simulation studies to develop new (or refined) retrieval algorithms for various applications that are specifically tailored towards capitalizing on the enhanced sensitivity of the quantum sensors. The project will prepare the scientific community for the new QSG data and aims to significantly enhance European competitiveness in quantum technology and satellite-based gravity monitoring. In the long-run, FEATS-G shall pave the way towards realizing the space component of a full-scale network of ground, airborne and space-based gravimeters for Earth observation purposes tailored towards research, commerce, and security applications by consolidating user requirements across different disciplines for a highly precise and global gravity field monitoring from space.