I had to look deeper to see that you are correct. There _have_ been several NASA published designs using microwaves or other EM for ordinary thrust, I'm afraid I thought the original article concerned one of those.
On review, as I mentioned elsewhere, I'll bet that this is really a "Dean Drive". The Dean Drive never worked well outside the designer's workshop, was never tested properly with a basic "pendulum" test, and seems to have been a basic "oscillation thruster": it interacted with the floor under it to provide net thrust. That would mean the system is not really "sealed", it's interacting with its environment in some subtle way.
From the description at http://motherboard.vice.com/re..., I'd guess EM interaction with the walls of the stainless steel vacuum chamber. And one of hte people I'd want to review the experiment would be James Randi, who's been helping debunk "mysterious mental force" claims for decades, and has a professional magician's eye for misdirection and sleight of hand.