抄録
As a mission after MAGELLAN, which is the NASA's next Venus explorer and will be launched in April 1989 for making a Radar map, a Venus exploration program is proposed here with the special interest in the origin and evolution of Venusian atmosphere. This program will make the exact measurements of the compositions of clouds and atmosphere under the cloud, the composition and temperature of the surface, and topography. By these measurements, we aim at: manifesting whether an ocean was present in the past, whether lots of water have escaped from Venus, whether the volcanic activity is/was present now/in the past, whether the plate tectonics is/was present, etc. We will also Study in detail the dynamics in the lower atmosphere, the origin of sulfur compounds, the history in the topographic structures, etc. In consequence, this program will use an orbiter and a balloon which will make a ground-base observation after the landing on the surface. More detailed description in English is available in the paper: A.Matsuzaki, ''Venus Exploration Relevant to Origin and Evolution of its Atmosphere Origin of Sulfur Dioxide as a Clue'', Proceedings of the 21 st ISAS Lunar and Planetary Symposium, July 7-9 1988, in press.
