I'd just like to point out that the satellite mission in question gets this measurement by comparatively weighing parts of the Earth through gravity gradients.

I'd just like to point out that the satellite mission in question gets this measurement by comparatively weighing parts of the Earth through gravity gradients. It's hard to do well, and GRACE and GOCE have done a great job. http://en.wikipedia.org/wiki/Gravity_Recovery_and_Climate_Experiment http://en.wikipedia.org/wiki/Gravity_Recovery_and_Climate_Ex... http://en.wikipedia.org/wiki/Gravity_Field_and_Steady-State_Ocean_Circulation_Explorer http://en.wikipedia.org/wiki/Gravity_Field_and_Steady-State_...