The MOCAST+ proposal for a quantum space gravimetry mission.

MOCAST+ (MOnitoring mass variations by Cold Atom Sensors and Time measures) is a study funded by the Italian Space Agency (ASI) and carried out by several Italian research groups, proposing a novel concept for a gravimetry mission based on quantum technology. Quantum technologies and quantum sensing promise to offer higher sensitivity, drift-free measurements, and higher absolute accuracy than "classical" sensors, both for terrestrial and space missions, giving access to more precise long-term measurements of the gravity field. In MOCAST+ the proposed payload is a Cold Atom Interferometer based on strontium atoms and acting as a gravity gradiometer, plus an optical frequency measurement using an ultra-stable laser, providing time measurements. We studied the level of accuracy which can be expected from the mission and the level of accuracy needed to detect and monitor phenomena identified in the Scientific Challenges of the ESA Living Planet Program, in particular Cryosphere, Ocean and Solid Earth. We will present the proposed payload, mission profile and preliminary platform design, and the results of end-to-end simulations and assessment of the impact on geophysical applications.