MOQAST-GEM (Mass Observation by QuAntum Sensors and Time measures from space – Gravity field of the Earth and Mars) is a study funded by the Italian Ministry of University and Research (MUR) in the frame of PRIN 2022. It started in February 2025 and will be completed in February 2027. Politecnico di Milano is Principal Investigator, with University of Firenze and University of Trieste participating in the project as partner teams.

The aim of the study is to carry out a research project furthering the knowledge of both the static and time-variable Earth gravity field and improving the knowledge of the gravity field of Mars, determining the benefits of a Quantum Space Gravimetry (QSG) mission.

The proposal is based on the concept of an innovative payload on board a constellation of satellites, exploited to obtain observations on the Earth gravity field and its potential. The payload is represented by Cold Atom Interferometers (CAI) and atomic clocks, the atomic species being Strontium. The Cold Atom Interferometers act as single-axis gradiometers, capable of observing second derivatives of the Earth gravitational potential, while pairs of atomic clocks on two different satellites along an orbit can provide measurements of differences of the gravitational potential.

Based on experimental tests and numerical simulations, it will be possible to assess the improvement provided by a QSG mission in the knowledge of:

• the time-variable Earth gravity field, enabling the monitoring of specific geophysical phenomena in a small area (e.g. detection and monitoring of daily, seasonal and yearly mass transport phenomena in the Alpine – Mediterranean range), assessing the possibility to exploit the data from such a mission to model the seasonal variations of hydrological basins and the ice-lake mass movements;
• the static Earth gravity field, hence improving the scientific readiness for natural resource exploration in terms of improving the lithosphere structure in countries lacking full geophysical data coverage as in parts of the African continent;
• in the area of planetary exploration, the gravity field of Mars, allowing to study the surface and subsurface of the planet with the goal to investigate the presence of sub-surface water, which is fundamental for the creation of extra-terrestrial habitats.

This project will benefit the Italian scientific community working on topics of Quantum Space Gravimetry, helping to consolidate the cooperation among researchers in the fields of Physics, Geodesy and Geophysics and to strengthen the Italian expertise on the matter, also improving the Scientific Readiness Level (SRL) of these studies.