The arm of the drive is a tuned mass damper attached to a voice coil that utilizes ground effect to maintain the a precise distance between the head and the pla

The arm of the drive is a tuned mass damper attached to a voice coil that utilizes ground effect to maintain the a precise distance between the head and the platter. Spinning disks wouldn't work in a vacuum using current technology, because there'd be no ground effect to lift the arm off the platter.