SPICAV IR acousto-optic spectrometer experiment on Venus Express
Résumé
SPICAV IR, a part of SPICAV/SOIR suite on Venus Express, is a compact single pixel spectrometer for the spectral range of 0.65-1.7 µm based on AOTF (acousto-optical tunable filter) technology. SPICAV IR is derived from SPICAM IR operating on Mars Express, the first AOTF spectrometer in the deep space, and adapted for Venus atmosphere measurements. The spectrometer sequentially measures spectra of reflected solar radiation from Venus on the dayside and the emitted Venus radiation in spectral "windows" on the nightside, and works also in solar occultation mode. The spectral range is 0.65-1.1 μm with spectral resolution of 7.8 cm−1, and 1-1.7 μm with spectral resolution of 5.2 cm−1. A description of this near-IR instrument, its calibration, in-flight performances, and the modes of operations on Venus' orbit are presented. A brief overview of the science measurements is given: water vapor measurements in the mesosphere on the day-side and near surface on the nightside, mapping of the O2(a1Δg) emission at 1.27 µm, aerosol studies via polarization and scattering solar radiation at the day-side, and measurements of aerosol properties at the tops of the clouds in solar occultations.