He who lives by gravity shall die by gravity. That’s what they say in the gravity biz, anyway. GROCE is the European “Gravity field and steady-state Ocean Circulation Explorer” Satellite which is a flying spacxe robot that has done some amazing research:
GOCE has a gradiometer with three accelerometers to measure gravity very accurately, to the level of 1 in 10^12th of Earth’s gravity. In other words, if an X went to within Y meters of the detector, the detector could tell based on X’s gravity. I’m not sure what X and Y are (I’m hoping someone who knows will fill in the blanks for us) but something like a mouse and one meter, I suspect. It also has a very accurate GPS system so I assume it could tell which side of the mouse it is located on were it located on a mouse. It also has an amazing system of moving around in space using ion-propulsion, so that it can track an orbit very accurately (otherwise it could not really do gravity research because it all depends on where you are … in relation to the mouse). It has other stuff too.
And the whole thing is going to come crashing down to earth ANY SECOND NOW.
As usual nobody knows where. Perhaps you can track it here.
The fancy machinery that GROCE uses to stay in exactly the right orbit is out of fuel, and so, the satellite will be crashed into the earth. Too bad they can’t refuel it!