Abstract :
ISHTAR or VENUS ORBITER is a mission to Venus similar to the mission Mars Express to Mars, with the use, possibly, of the same spacecraft and subsystems. This mission has been proposed to ESA for a feasibility study as a small mission (F2, F3). We shall describe here briefly the scientific objectives of the mission, and how could be implemented. The scientific objectives of the mission are evenly distributed in three broad areas: atmospheric science, planetary interior and surface, and interaction with the solar wind. Ishtar will study the surface and the atmosphere of the planet by making use of remote sensing instruments, and, if possible, by a descending meteorological balloon/lander. The model payload of the orbiter should include an Imaging Spectrometer, a Fourier Spectrometer, a Radar imaging/altimeter, a UV spectrometer and a Plasma Package studying also the Energetic Neutral Atoms population resulting from the plasma interaction with the planetary atmosphere.
