ACS experiment for atmospheric studies on “ExoMars-2016” Orbiter

Korablev, Oleg; Montmessin, Franck; Fedorova, Anna; Ignatiev, N.; Shakun, Alexei; Trokhimovskiy, Alexander; Grigoriev, A.; Anufreichik, K.; Kozlova, T. O.

doi:10.1134/s003809461507014x

Cited by 19 publications

(9 citation statements)

References 29 publications

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“…The NOMAD and ACS instruments on TGO are designed to provide the first vertical profile measurements of methane on Mars by applying the highly sensitive solar occultation technique [ Vandaele et al ., ; Korablev et al ., ]. NOMAD is planned to measure two vertical profiles per orbit at latitudes that vary smoothly throughout the Martian year [ Vandaele et al ., ].…”

Section: Discussionmentioning

confidence: 99%

“…The upcoming European Space Agency (ESA)/Roskosmos ExoMars Trace Gas Orbiter (TGO) mission (launch foreseen in March 2016) carries two instruments that are designed to measure the first vertical profiles of methane with high sensitivity and to do so in a mode of systematic diurnal monitoring throughout a full Mars year. These are the Nadir and Occultation for Mars Discovery (NOMAD) spectrometer suite [ Vandaele et al ., ], with expected detection limit for methane of 25 parts per trillion by volume and a vertical resolution of ~1 km, and the Atmospheric Chemistry Suite (ACS) [ Korablev et al ., ]. In anticipation of their measurements it is important to better understand the behavior of methane also in the vertical after an emission from the surface.…”

Section: Introductionmentioning

confidence: 99%

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Formation of layers of methane in the atmosphere of Mars after surface release

Viscardy

Daerden

Neary

2016

Geophysical Research Letters

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Simulations with a general circulation model for the atmosphere of Mars show that surface emissions of methane can result in a highly nonuniform vertical distribution throughout the atmosphere, including the formation of layers, during the first weeks after the release. The fate of the released methane is determined by the global circulation pattern at the time of the release, and the methane can be transported to locations over the planet that are remote from the emission site. It typically takes several weeks for the methane to become more uniformly mixed, implying that the detection of vertical layers of methane can be indicative of recent surface emission. This puts the existing observations in a new perspective and will allow instruments on the upcoming ExoMars Trace Gas Orbiter mission to detect signatures of surface emission activity as they are designed to measure the first vertical profiles of methane on Mars.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Formation of layers of methane in the atmosphere of Mars after surface release

Viscardy

Daerden

Neary

2016

Geophysical Research Letters

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“…It may be that life is remotely detectable only through spectral evidence for pigments (Rule B), strengthened by isotopic and compositional measurements and, perhaps, observations of organic compounds such as PAHs. For methane on Mars, the next insights may come from the ExoMars Trace Gas Orbiter (Korablev et al, 2015 ; Vandaele et al, 2015 ).…”

Section: Application To Past Attempts At Life Detectionmentioning

confidence: 99%

The Ladder of Life Detection

Neveu

Hays

Voytek³

et al. 2018

Astrobiology

197

171

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We describe the history and features of the Ladder of Life Detection, a tool intended to guide the design of investigations to detect microbial life within the practical constraints of robotic space missions. To build the Ladder, we have drawn from lessons learned from previous attempts at detecting life and derived criteria for a measurement (or suite of measurements) to constitute convincing evidence for indigenous life. We summarize features of life as we know it, how specific they are to life, and how they can be measured, and sort these features in a general sense based on their likelihood of indicating life. Because indigenous life is the hypothesis of last resort in interpreting life-detection measurements, we propose a small but expandable set of decision rules determining whether the abiotic hypothesis is disproved. In light of these rules, we evaluate past and upcoming attempts at life detection. The Ladder of Life Detection is not intended to endorse specific biosignatures or instruments for life-detection measurements, and is by no means a definitive, final product. It is intended as a starting point to stimulate discussion, debate, and further research on the characteristics of life, what constitutes a biosignature, and the means to measure them.

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“…In particular, the presence of two spectroscopic suites, Nadir and Occultation for Mars Discovery (NOMAD; Vandaele et al , 2015 ) and Atmospheric Chemistry Suite (ACS; Korablev et al , 2015 ), will help TGO cover several distinct areas: Analyzing the present-day chemical composition of the martian atmosphere through the detection of a broad suite of trace gases and key isotopes. Covering 14 UV, visible, and IR spectral ranges, NOMAD and ACS will ensure that a large number of species are detectable, such as CO 2 (including 13 CO 2 , 17 OCO, 18 OCO, and C 18 O 2 ), CO (including 13 CO and C 18 O), H 2 O (including HDO), NO 2 , N 2 O, O 3 , CH 4 (including 13 CH 4 and CH 3 D), C 2 H 2 , C 2 H 4 , C 2 H 6 , H 2 CO, HCN, OCS, SO 2 , HCl, HO 2 , and H 2 S. The high resolution of the NOMAD IR channels will provide highly resolved spectra, allowing unambiguous separation of absorption lines and thus ensuring a high sensitivity for the search of trace gases (see Robert et al , 2016 , for a detailed analysis of the sensitivity of the NOMAD instrument).…”

Section: Exomars Tgomentioning

confidence: 99%

Methane on Mars and Habitability: Challenges and Responses

et al. 2018

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Recent measurements of methane (CH4) by the Mars Science Laboratory (MSL) now confront us with robust data that demand interpretation. Thus far, the MSL data have revealed a baseline level of CH4 (∼0.4 parts per billion by volume [ppbv]), with seasonal variations, as well as greatly enhanced spikes of CH4 with peak abundances of ∼7 ppbv. What do these CH4 revelations with drastically different abundances and temporal signatures represent in terms of interior geochemical processes, or is martian CH4 a biosignature? Discerning how CH4 generation occurs on Mars may shed light on the potential habitability of Mars. There is no evidence of life on the surface of Mars today, but microbes might reside beneath the surface. In this case, the carbon flux represented by CH4 would serve as a link between a putative subterranean biosphere on Mars and what we can measure above the surface. Alternatively, CH4 records modern geochemical activity. Here we ask the fundamental question: how active is Mars, geochemically and/or biologically? In this article, we examine geological, geochemical, and biogeochemical processes related to our overarching question. The martian atmosphere and surface are an overwhelmingly oxidizing environment, and life requires pairing of electron donors and electron acceptors, that is, redox gradients, as an essential source of energy. Therefore, a fundamental and critical question regarding the possibility of life on Mars is, “Where can we find redox gradients as energy sources for life on Mars?” Hence, regardless of the pathway that generates CH4 on Mars, the presence of CH4, a reduced species in an oxidant-rich environment, suggests the possibility of redox gradients supporting life and habitability on Mars. Recent missions such as ExoMars Trace Gas Orbiter may provide mapping of the global distribution of CH4. To discriminate between abiotic and biotic sources of CH4 on Mars, future studies should use a series of diagnostic geochemical analyses, preferably performed below the ground or at the ground/atmosphere interface, including measurements of CH4 isotopes, methane/ethane ratios, H2 gas concentration, and species such as acetic acid. Advances in the fields of Mars exploration and instrumentation will be driven, augmented, and supported by an improved understanding of atmospheric chemistry and dynamics, deep subsurface biogeochemistry, astrobiology, planetary geology, and geophysics. Future Mars exploration programs will have to expand the integration of complementary areas of expertise to generate synergistic and innovative ideas to realize breakthroughs in advancing our understanding of the potential of life and habitable conditions having existed on Mars. In this spirit, we conducted a set of interdisciplinary workshops. From this series has emerged a vision of technological, theoretical, and methodological innovations to explore the martian subsurface and to enhance spatial tracking of key volatiles, such as CH4.

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ACS experiment for atmospheric studies on “ExoMars-2016” Orbiter

Cited by 19 publications

References 29 publications

Formation of layers of methane in the atmosphere of Mars after surface release

Formation of layers of methane in the atmosphere of Mars after surface release

The Ladder of Life Detection

Methane on Mars and Habitability: Challenges and Responses

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