That's a nice overview paper. There is much value in the gravimetric mapping realm and we're not even close to the limits of what people are imagining. For in

That's a nice overview paper. There is much value in the gravimetric mapping realm and we're not even close to the limits of what people are imagining. For instance, by combining multiple ultra-precise orbiting clocks with quantum teleportation networks linking them for time transfer one could gravimetrically map the planet in 3D at millimeter resolutions. E.g.: these clocks would be able to carefully map the shape of Earth’s terrain down to the millimeter. “You’d be able to see someone digging a tunnel under the U.S.-Mexico border from space” [1] One other capability of such a system: whoever possessed it would be able to locate every single significant concentration of dense matter, e.g., plutonium on the planet no matter where it was stored. They would know exactly how many nuclear weapons, etc. everyone had and exactly where they were keeping them. [1] https://www.sciencenews.org/article/quantum-timekeeping https://www.sciencenews.org/article/quantum-timekeeping (paywall)