When I think of pretty gravity experiments, there are many, as the form must follow the function and gravity is geometry.
I'm particularly partial to the laser-ranging satellites:
https://en.wikipedia.org/wiki/LAGEOS
https://en.wikipedia.org/wiki/LARES_(satellite)
LARES is particularly cool, as it is (and may forever be) the densest object of its mass in the solar system. As so many gravity experiments go, systematic uncertainties are more-important than raw signal, though, so LARES 2 is composed of nickel instead of tungsten. It'll still be quite a day when LARES 1 re-enters; it'd be quite a sight to see.
Dropping a half-ton, two-foot-diameter, sphere of brass out of orbit is something of a health hazard to whatever life forms might have to catch it. If Miley Cyrus needs a follow-up hit, "Wrecking Ball" and "LAGEOS" have the same number of syllables.
Can't be much at 250km though.
Aircraft use the surrounding air as support to counter the gravity. While lift has been measured for GOCE at different angles of attack, it never used it to stay at its altitude; the "wings" were just solar panels to feed the power-hungry engine. At GOCE operating altitudes, the air is sparse, Knudsen number is high, and the aerodynamics differ quite a bit. It wasn't an aircraft, it was a "satelloid", an old idea that got implemented.
They use the fact that higher densities of gravity on the earth below accelerate one sattelite before the other. So the way they measure gravity is by very accuratly measuring the fluctuations in the distances of the sattelites.
This is a feat in itself, the sattelites are 200 km apart and the fluctuations are on the scale of the strength of a hair.
Maybe there are better more precise ways of measuring local gravity from space, but this is just so clever.
doesn't the layman definition of "aircraft" require air?
great compliment for Ferrari!
GOCE: https://en.wikipedia.org/wiki/Gravity_Field_and_Steady-State...
It's a gravity survey satellite. They get better measurements if they fly closer to the earth, so there's a motivation to lower the orbit. GOCE flies so low that it needs to take aerodynamics into account, so it is sleek, like an aircraft.*
* It is, of course, actually an aircraft, like all satellites, to some degree, at least in the layman's definition of the word.