The article is not very clear, and has no technical details, and has not a reference to a peer review journal article. So it is very difficult to know if this theoretical device really works.<p>I'm not sure, but it even looks like a perpetual motion example. (But it could be a problem with the press report.)<p>And the article says that is a variation of the "Differential sail", but the most clear reference in Wikipedia ( <a href="http://en.wikipedia.org/wiki/Breakthrough_Propulsion_Physics_Program" rel="nofollow">http://en.wikipedia.org/wiki/Breakthrough_Propulsion_Physics...</a> ) has many proposed devices that are very controversial and probably violates some physics laws.