Competitive with classic inertial sensors, quantum gradiometers based on CAI are exceptional new devices, which hold the promise to measure inertial forces with an unprecedented level sensitivity (≈mE/√Hz). Mechanical effects of light pulses are exploited to spatially separate and recombine the wavepackets of cooled atoms, which, thus, interfere; by engineering 3D specific instrument configurations, from the interferometer phase shift all elements of the gravity gradient tensor could be traced back, as well as the full spacecraft angular velocity vector. This performance is enhanced by the high common-mode rejection of noise, due to the differential nature of gradiometers’ measurements. Furthermore, in space, the microgravity environment prolongs the atoms’ interrogation time, improving the interferometer sensitivity. On top of this, CAI’s spectral behaviour features a very low flat white noise over the entire frequency range. Another advantage of these sensors is the absence of moving parts, making them drift-free and yielding no need for instrument recalibration, fundamental for deep-space payloads. In the current hectic scenario of exploration campaigns to Mars, the latter is deemed an excellent case study for a CAI-based gradiometry mission as refined gravity field models are required to further our understanding of the Red Planet. To this end, missions must be designed to sustain continuous monitoring of the target body and uniform global sampling, ensured by selecting an appropriate orbit (low and polar).
Both analytic and numerical covariance analysis approaches are adopted to retrieve the Spherical Harmonics (SH) coefficients’ error spectra, for several CAI-based mission concepts with different orbit geometries. Compared to the latest gravity field model of Mars (MRO120F), with a maximum SH degree of 120, the treated missions can achieve degree strengths up to 390 for the static gravity field. At degree 120, the maximum SNR is about 10^3 with the most sensitive instruments. Exploiting these exceptional results, several scientific objectives can be addressed, regarding the crust and lithosphere structure, the planetary thermal evolution, the magmatism and diverse geological features, such as impact basins and quasi-circular depressions.