Interesting Fact: Did you know that the ISS is one of the worst-designed dynamic structures? it is an undamped system (apart from earth's gravity) The whole thing acts like a giant spring..it can actually be seen to flap and wobble about. Also, this 'giant spring' is constantly falling back to earth and needs to be boosted back into orbit every now and then.

there is no such thing as a stable gravitational orbit, everything falls toward everything without being boosted back out every now and then

Wasn't there something back in the 1980's about using the Lagrange points (the points at which the Moon's and Earth's gravitational pulls were equalized) as a place where you could hang an object in orbit without needing periodic boosts? Was that too far from Earth's orbit for the ISS, or was there another reason why it wasn't placed at one of those points?

There are 5 Lagrange points, three of which are unstable (L1 thru L3). L4 and L5 are infinitesimaly stable, though a nonlinear analysis proves a certain stability to them. They form an equilateral triangle with the Earth and the moon, implying they are equidistant from each other. L4 and L5 are 1 earth-moon distance away form us.
Would be an advantageous place to put something....