Point-mass sensitivity of gravimetric satellites

Frequency-domain expressions are found for gradiometer and satellite-to-satellite tracking measurements of a point source on the surface Earth. The maximum signal-to-noise ratio as function noise in measurement apparatus is computed, from that minimum detectable mass inferred. A magnitude M3=100Gt gives 3 when GOCE-like passes directly over mass. On mission GRACE-FO M3=1.3Gt microwave instrument M3=0.5Gt laser ranging interferometer. sensitivity future GRACE-like missions with different orbital parameters improved accelerometer explored, optimum spacecraft separation detecting point-like sources found. future-mission benefit improving non-gravitational disturbances shown by resulting reduction M3, to small 7 Mt 500 km altitude optimized satellite 900 km.