Before revision: It builds upon the "heliogyro" conceptHeliogyro by Richard H. MacNeal, published in 1971, MacNeal R. H., "Structural Dynamics of the Heliogyro", NASA-CR-1745A, 1971.Burton, R. L., Coverstone, V. L., Hargens-Rysanek, J., Ertmer, K. M., and Botter, T., "Ultrasail-Ultra-Lightweight Solar Sail Concept," 41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference Exhibit, AIAA Paper 2005-4117, 2005.
After revision: It builds upon the "heliogyro" concept by Richard H. MacNeal, published in 1971,