Yes it is not hard to minipulate gravity. if you do not belive me then think on this.
The earth we live on has a gravitational field with a field strength 1g. Now we wish to reproduce the effects of gravity artificilly in the lab. But to do this we first have to be able to find a theory free envrionment or at least free of any theorys developed since 1915 if you can do this then you have half a chance.
Now once we have a theory free enviroment we can go to work on the truth or facts, in this case these facts are;
1; we live on a planet that has a gravity value of 1g.
2; this planet has mass, but what properties does this mass have, is it not magnetic!
3; the planet is moving around on its axis, one revolution every 24 hours.
" it Spins"
Now, with out going further we can already come up with a simple mathamatical equasion to help us scale down the mass by increasing the velocity and of course the equasion is E=M V2 which is Einstein's original works not C2 as told to us today.
So if we now substitute the known figures into the equasion we get
the Energy required = the Magnetic Mass of the planet, multiplied by its spinning velocity squared.
so E = _____ kg * 1 revolution/24hrs squared
therefore if we wish to reduce the magnetic mass to 1kg then the rate or spin must increase proportunatly. all of this information we new before we left high school.
As to Tesla well remember all you need to get electricity is a coil moving past a magnet or a magnet moving past a coil and by simple induction you will get electricity. this is also governed by the size of the coil, and in Tesla's case these coils were as large as a house.
motors a scaled down version of the planet and his coil.