INTRODUCTION We propose a solar-powered aircraft system for With the success of missions such as the Mars the exploration of Venus. The atmosphere of Pathfinder, exploration of the planet Mars has Venus provides several advantages for flying a received a large amount of public attention, and has solar-powered aircraft. At the top of the cloud recently been suggested as an environment for level, the solar intensity is comparable to or greater flying a powered aircraft. Venus, Earth's evil twin, than terrestrial solar intensities. The atmospheric is also an extremely interesting planet, but far less pressure makes flight much easier than on planets studied. Because of a white cloud cover that such as Mars. Also, the slow rotation of Venus reflects most of the incident solar radiation back allows an airplane to be designed for flight within into space, the planet Venus actually absorbs less continuous sunlight, eliminating the need for energy from the sun than the Earth, despite its energy storage for nighttime flight. These factors orbital position 27% closer to the sun. make Venus a prime choice for a long-duration Venus ig nearly same gize ag Earth; faut solar-powered aircraft. Fleets of solar-powered utterl ^^ Earth [1>2] Due tQ a mn aircraft could provide an architecture for efficient greenhouse effect> the temperature of the surface is and low-cost comprehensive coverage for a variety neariv 500° C of scientific missions. 1 *Engineer, Photovoltaics and Space Environmental Effects Branch, NASA John Glenn Research Center. Associate fellow, AIAA Copyright ©2002 by the American Institute of Aeronautics and Astronautics, Inc. No copyright is asserted in the United States under Title 17, U. A. Code. The U. S. Government has a royalty-free license to exercise all rights under the copyright claimed herein for Government purposes. All other rights are reserved by the copyright holder.