Project C06 deals with the design of next-generation satellite gravimetry from VLEO constellations beyond the ESA-NASA double-pair concept of the MAGIC mission. The successful candidate will engage in extensive closed-loop simulation studies in order to explore the vast design parameter space of gravity signal, orbit choice, sensor technology and spatio-temporal sampling. In a forward step, potential VLEO constellations are simulated and time-variable Earth gravity field components will be transformed into gravity signals along the orbits. Then, assuming certain observation techniques with their hardware specifications and corresponding error characteristics, the reverse step in the simulation loop consists of parametrizing the time-variable gravity field and retrieving gravity field parameters through optimal estimation techniques. Assessing output against input closes the loop and provides information on the quality of each individual simulated mission scenario. The candidate will interact with the thematically neighbouring CRC-projects, mostly from research domain C.