SPICAV on Venus Express: Three spectrometers to study the global structure and composition of the Venus atmosphere

摘要: Abstract Spectroscopy for the investigation of characteristics atmosphere Venus (SPICAV) is a suite three spectrometers in UV and IR range with total mass 13.9 kg flying on Express (VEX) orbiter, dedicated to study from ground level outermost hydrogen corona at more than 40,000 km. It derived SPICAM instrument already board Mars (MEX) great success, addition new high-resolution spectrometer, solar occultation (SOIR), working mode. The consists simple data processing unit providing interface these channels spacecraft. A spectrometer (118–320 nm, resolution 1.5 nm) identical MEX version. nadir viewing, limb viewing vertical profiling by stellar occultation. In orientation, SPICAV will analyse albedo spectrum (solar light scattered back clouds) retrieve SO2, distribution UV-blue absorber (of still unknown origin) dayside implications cloud structure atmospheric dynamics. On nightside, γ δ bands NO be studied, as well emissions produced electron precipitations. mode sensor measure profiles CO2, temperature, SO, clouds aerosols. density/temperature obtained constrain aid development dynamical models, top (∼60 km) 160 km atmosphere. This essential future missions that would rely aerocapture aerobraking. observations upper allow studies ionosphere through CO, CO+, CO2+, its direct interaction wind. H corona, two different scale heights, it better understanding escape mechanisms estimates their magnitude, crucial insight into long-term evolution VIS-IR (0.7–1.7 μm, 0.5–1.2 nm) employs pioneering technology: an acousto-optical tunable filter (AOTF). thermal emission peeping clouds, complementing both VIRTIS Planetary Fourier Spectrometer (PFS) VEX. this channel H2O, SOIR λ=2.2–4.3 μm, spectral λ/Δλ>15,000, highest concept includes combination echelle grating AOTF crystal sort out one order time. main objective HDO H2O occultation, characterize D atoms give about water Venus. also isotopes CO2 minor species, provides sensitive search species attempt nightside emission, which measurement lower atmosphere, compared ratio possibly discover constituents.