Search Publications
Calibration of NOMAD on ESA's ExoMars Trace Gas Orbiter: Part 1 - The Solar Occultation channel
Vandaele, Ann Carine; Neefs, Eddy; Aoki, Shohei +17 more
Nadir and Occultation for MArs Discovery (NOMAD) is a 3-channel spectrometer suite that is currently orbiting Mars onboard ESA's ExoMars Trace Gas Orbiter, measuring the composition of the Martian atmosphere in unprecedented detail. Of the three channels, two operate in the infrared: the Solar Occultation (SO) channel observes gas species in the 2…
Calibration of the NOMAD-UVIS data
Vandaele, Ann Carine; Neefs, Eddy; Aoki, Shohei +23 more
The Ultraviolet and VIsible Spectrometer (UVIS), covering the 200-650 nm range, is one of three spectrometers that comprise the NOMAD instrument on the ExoMars 2016 Trace Gas Orbiter (TGO). UVIS can operate in solar occultation, nadir and limb viewing mode and was designed to monitor ozone and aerosols in the Martian atmosphere. Here, we describe …
Multiband photometry of Martian Recurring Slope Lineae (RSL) and dust-removed features at Horowitz crater, Mars from TGO/CaSSIS color observations
Pajola, M.; Cremonese, G.; Thomas, N. +12 more
Recurring Slope Lineae (RSL) are narrow, dark streaks typically lengthening down Martian steep slopes during warm seasons, fading during the cold ones and regularly recurring every Martian year. Their origin is still debated. Although initially interpreted as possible flows of seeping water, either coming from a subsurface aquifer or through atmos…
Water vapor saturation and ice cloud occurrence in the atmosphere of Mars
Vandaele, Ann Carine; Aoki, Shohei; Kleinböhl, Armin +3 more
We investigate water vapor saturation in the martian atmosphere in the presence or proximity of water ice clouds. We evaluate mixing ratio profiles of ambient water vapor derived from measurements by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and the Nadir and Occultation for MArs Discovery (NOMAD) instrument in comparison wi…
Absolute calibration of the Colour and Stereo Surface Imaging System (CaSSIS)
Almeida, Miguel; Cremonese, Gabriele; Thomas, Nicolas +5 more
The Colour and Stereo Surface Imaging System (CaSSIS) onboard the ExoMars Trace Gas Orbiter (TGO) has observed several standard stars and Jupiter with the aim of deriving the absolute calibration factors that convert observed signal into reflectance ("I over F"). The targets were observed through all four colour filters and hence a relative calibr…
Geology, in-situ resource-identification and engineering analysis of the Vernal crater area (Arabia Terra): A suitable Mars human landing site candidate
Pajola, M.; Cremonese, G.; Thomas, N. +15 more
A multidisciplinary study of an ancient area of Mars (Early to Late Noachian) located in Arabia Terra is presented, centred at 6°1′N, 354°54′ E and including the 55 km size Vernal crater. By means of different spatial scale imagery datasets and digital terrain models (MOLA, THEMIS, HRSC, CTX, CaSSIS and HiRISE), we prepare a high-resolution geolog…
CaSSIS-based stereo products for Mars after three years in orbit
Mège, Daniel; Pajola, Maurizio; Cremonese, Gabriele +10 more
The Colour and Stereo Surface Imaging System (CaSSIS) on board the ExoMars Trace Gas Orbiter (TGO), operating in push-frame mode, provides multiband images at four different wavelengths thanks to a Filter Strip Assembly with a panchromatic filter and three broadband filters within the visible and near infrared range. The camera acquires stereo pai…
Removal of straylight from ExoMars NOMAD-UVIS observations
Vandaele, Ann Carine; Daerden, Frank; Ristic, Bojan +13 more
We present an in-flight straylight removal method for the Ultraviolet and Visible Spectrometer (UVIS) channel of the Nadir and Occultation for Mars Discovery (NOMAD) instrument aboard the ExoMars Trace Gas Orbiter (TGO). The presence of a 'red-leak' straylight signal in the UVIS instrument was discovered post-launch in ground calibration measureme…
Calibration of NOMAD on ESA's ExoMars Trace Gas Orbiter: Part 2 - The Limb, Nadir and Occultation (LNO) channel
Vandaele, Ann Carine; Neefs, Eddy; Aoki, Shohei +19 more
The Nadir and Occultation for MArs Discovery (NOMAD) instrument is a 3-channel spectrometer suite on the ESA ExoMars Trace Gas Orbiter. Since April 2018, when the nominal science mission began, it has been measuring the constituents of the Martian atmosphere. NOMAD contains three separate spectrometers, two of which operate in the infrared: the So…
Seasonal southern circum-polar spots and araneiforms observed with the colour and stereo surface imaging system (CaSSIS)
Tornabene, Livio L.; Cremonese, Gabriele; Thomas, Nicolas +5 more
The southern polar area of Mars is home to various seasonal activity commonly explained by the Kieffer model. During southern spring, the ice covering the polar area sublimates and leaves distinct features (spiders, spots, fans) observable from orbit. The Colour and Stereo Surface Imaging System (CaSSIS) onboard the ExoMars Trace Gas Orbiter (TGO)…