Large gray sphere sphere slowly landing.While driving on highway 521, while approaching Andrews, SC, I saw a strange looking object hovering a few hundred yards above the tree line. I could only see it through breaks in the trees as I drove by, but it did not seem to move very much in about 5 minutes time, except slowly down.It was out the driver's side window, and it was initially tilted at a 45 degree angle, pointing up in the direction I was traveling. The object was pointing parallel with me, more or less.It was grey in color, and it appeared to be a matte sphere with some rigid supports attached in a pyramid shape. They seemed to be metal tubes. The object appeared to be about 30 feet long total, with the sphere at what looked to be the size of a water tower tank. It was hovering in the air and did not appear to be tethered in any way. Eventually it descended down below the tree line and appeared to be landing very slowly. The craft rotated counter-clockwise and the supports then seemed to resemble landing struts.