The Planetary Fourier Spectrometer (PFS) onboard the European Mars Express mission

International audience; The Planetary Fourier Spectrometer (PFS) for the Mars Express mission is an infrared spectrometer optimised for atmospheric studies. This instrument has a short wave (SW) channel that covers the spectral range from 1700 to 8200.0cm-1 (1.2- 5.5mum) and a long-wave (LW) channel that covers 250- 1700cm-1 (5.5- 45mum). Both channels have a uniform spectral resolution of 1.3cm-1. The instrument field of view FOV is about 1.6o (FWHM) for the Short Wavelength channel (SW) and 2.8o (FWHM) for the Long Wavelength channel (LW) which corresponds to a spatial resolution of 7 and 12 km when Mars is observed from an height of 250 km. PFS can provide unique data necessary to improve our knowledge not only of the atmosphere properties but also about mineralogical composition of the surface and the surface-atmosphere interaction. The SW channel uses a PbSe detector cooled to 200-220 K while the LW channel is based on a pyroelectric ( LiTaO3) detector working at room temperature. The intensity of the interferogram is measured every 150 nm of physical mirrors displacement, corresponding to 600 nm optical path difference, by using a laser diode monochromatic light interferogram (a sine wave), whose zero crossings control the double pendulum motion. PFS works primarily around the pericentre of the orbit, only occasionally observing Mars from large distances. Each measurements take 4 s, with a repetition time of 8.5 s. By working roughly 0.6 h around pericentre, a total of 330 measurements per orbit will be acquired 270 looking at Mars and 60 for calibrations. PFS is able to take measurements at all local times, facilitating the retrieval of surface temperatures and atmospheric vertical temperature profiles on both the day and the night side

A dynamic upper atmosphere of Venus as revealed by VIRTIS on Venus Express

The upper atmosphere of a planet is a transition region in which energy is transferred between the deeper atmosphere and outer space. Molecular emissions from the upper atmosphere (90–120 km altitude) of Venus can be used to investigate the energetics and to trace the circulation of this hitherto little-studied region. Previous spacecraft1 and ground-based2, 3, 4 observations of infrared emission from CO2, O2 and NO have established that photochemical and dynamic activity controls the structure of the upper atmosphere of Venus. These data, however, have left unresolved the precise altitude of the emission1 owing to a lack of data and of an adequate observing geometry5, 6. Here we report measurements of day-side CO2 non-local thermodynamic equilibrium emission at 4.3 microm, extending from 90 to 120 km altitude, and of night-side O2 emission extending from 95 to 100 km. The CO2 emission peak occurs at approx115 km and varies with solar zenith angle over a range of approx10 km. This confirms previous modelling7, and permits the beginning of a systematic study of the variability of the emission. The O2 peak emission happens at 96 km plusminus 1 km, which is consistent with three-body recombination of oxygen atoms transported from the day side by a global thermospheric sub-solar to anti-solar circulation, as previously predicte

VIRTIS: The Visible and Infrared Thermal Imaging Spectrometer

The VIRTIS imaging spectrometer built for ESA's Rosetta cometary mission is a versatile instrument that is also well-suited to Venus observations. The discovery of the near-IR windows in the atmosphere of Venus from ground-based observations in the 1980s showed that the surface of the planet can be studied via IR observations over the nightside. Imaging spectroscopy in the visible and near-IR can study the atmosphere from the uppermost layers down to the deepest levels. With its unique combination of mapping capabilities at low spectral resolution (VIRTIS-M) and high spectral resolution slit spectroscopy (VIRTIS-H), the instrument is ideal for making extensive IR and visible spectral images of the planet

VIRTIS: The Visible and Infrared Thermal Imaging Spectrometer

The VIRTIS imaging spectrometer built for ESA's Rosetta cometary mission is a versatile instrument that is also well-suited to Venus observations. The discovery of the near-IR windows in the atmosphere of Venus from ground-based observations in the 1980s showed that the surface of the planet can be studied via IR observations over the nightside. Imaging spectroscopy in the visible and near-IR can study the atmosphere from the uppermost layers down to the deepest levels. With its unique combination of mapping capabilities at low spectral resolution (VIRTIS-M) and high spectral resolution slit spectroscopy (VIRTIS-H), the instrument is ideal for making extensive IR and visible spectral images of the planet

VIRTIS: The Visible and Infrared Thermal Imaging Spectrometer

The VIRTIS imaging spectrometer built for ESA's Rosetta cometary mission is a versatile instrument that is also well-suited to Venus observations. The discovery of the near-IR windows in the atmosphere of Venus from ground-based observations in the 1980s showed that the surface of the planet can be studied via IR observations over the nightside. Imaging spectroscopy in the visible and near-IR can study the atmosphere from the uppermost layers down to the deepest levels. With its unique combination of mapping capabilities at low spectral resolution (VIRTIS-M) and high spectral resolution slit spectroscopy (VIRTIS-H), the instrument is ideal for making extensive IR and visible spectral images of the planet

VIRTIS: The Visible and Infrared Thermal Imaging Spectrometer

The VIRTIS imaging spectrometer built for ESA's Rosetta cometary mission is a versatile instrument that is also well-suited to Venus observations. The discovery of the near-IR windows in the atmosphere of Venus from ground-based observations in the 1980s showed that the surface of the planet can be studied via IR observations over the nightside. Imaging spectroscopy in the visible and near-IR can study the atmosphere from the uppermost layers down to the deepest levels. With its unique combination of mapping capabilities at low spectral resolution (VIRTIS-M) and high spectral resolution slit spectroscopy (VIRTIS-H), the instrument is ideal for making extensive IR and visible spectral images of the planet

VIRTIS: The Visible and Infrared Thermal Imaging Spectrometer

The VIRTIS imaging spectrometer built for ESA's Rosetta cometary mission is a versatile instrument that is also well-suited to Venus observations. The discovery of the near-IR windows in the atmosphere of Venus from ground-based observations in the 1980s showed that the surface of the planet can be studied via IR observations over the nightside. Imaging spectroscopy in the visible and near-IR can study the atmosphere from the uppermost layers down to the deepest levels. With its unique combination of mapping capabilities at low spectral resolution (VIRTIS-M) and high spectral resolution slit spectroscopy (VIRTIS-H), the instrument is ideal for making extensive IR and visible spectral images of the planet