Ion Propulsion is a technology that is most utilized by companies like NASA that deal with space travel.  This idea is incredible for this application as, in space, you don't weigh anything and ion propulsion, even though it isn't very powerful on Earth, is perfect to propel you in space.  This propulsion  is caused by the ionization of air.  On the tops of the posts found at the vertices of these shapes, their is a copper wire that lines the perimeter of the shape.   This is known as the Corona Wire.  The foil skirt below is known as the Collector.  High voltage electricity is passed through this open circuit where ionized air particles will travel from the Corona Wire to the Collector completing the circuit and causing a small amount of propulsion.