The Magenn Power Air Rotor System (MARS) is an innovative lighter-than-air tethered device that rotates about a horizontal axis in response to wind, efficiently generating clean renewable electrical energy at a lower cost than all competing systems. "Electrical power generated at the floating Air Rotor is transferred down the tether to ground level equipment. Depending on size of the Air Rotor, power is sent to users ranging from campers to large power grids. Helium (an inert non-flammable lighter-than-air gas) sustains the Air Rotor which ascends to an altitude for best winds. No towers or heavy foundations are necessary and sizes range from small "backpack" models to large megawatt generating devices."