He is wearing a small digital lens kit on the left eye that allows him to view and interact with holographic images and digitally generated moving parts. He looks like he is randomly miming nothing in thin air but he is actually remotely adjusting plasma vents and radiation emitters behind the bulkhead and operating moving parts on the outside of the ship from the safety of the inside.

Judging from the reactions of the rest of the crew walking past … Ensign Jimmy Turny Knob is just going through a normal day at work.