The machine is described in the script:
INT. CAPE CANAVERAL - CONTROL ROOM - DAY
MAIN MONITOR
The alien, spherical pod rests on a complex drop mechanism that in turn hangs from an overhead track. The track extends out along the long gangry arm that hangs over the top of the machine's three immense concentric rings.
Click the small images to see larger versions of the sketches and computer renderings of the massive machine in various stages of completion.

When the rings spin, they sound like this...aif or wav
©1997 Warner Bros.