In past times life might have occurred in Martian conditions milder than the present ones and lef... more In past times life might have occurred in Martian conditions milder than the present ones and left some remnants at the surface Even if this did not happen prebiotic molecules may have been be preserved that might be similar to the ones that prevailed on Earth surface some 3 5 to 4 billion years ago NASA s MSL09 rover will
Since the beginning of the space exploration, most of the many probes which have been sent to exp... more Since the beginning of the space exploration, most of the many probes which have been sent to explore other planetary atmospheres and surfaces carried instruments to determine their elemental, isotopic and molecular -inorganic as well as organic- compositions. As Mass Spectrometry (MS) and Gas Chromatography (GC) are powerful analytical techniques which fulfil the severe constraints of space instrumentation (mass, size, mechanical strength, automation and energy consumption), they have been the techniques the most frequently used for in situ chemical analysis of extraterrestrial environments, essentially Mars and Venus in the 70s and 80s. After 20 years and the investigation of Venus atmosphere by the Vega probe, they will be used again next year to investigate the atmosphere of a fascinating world : Titan Because of its composition (rich in organics) and density (similar to the Earth's one), the study of the atmosphere of Titan is of primary interest for understanding a reducin...
Origins of life and evolution of the biosphere : the journal of the International Society for the Study of the Origin of Life, 1998
Titan, the largest satellite of Saturn, has an atmosphere chiefly made up of N2 and CH4, and incl... more Titan, the largest satellite of Saturn, has an atmosphere chiefly made up of N2 and CH4, and including many organics. This atmosphere also partly consists of hazes and aerosol particles which shroud the surface of this satellite, giving it a reddish appearance. The aerosols observed in Titan's atmosphere are thought to be synthesized at high altitudes (>300 km) and fall to the surface. Varying with temperature profiles, condensation phenomena take place in the lower atmosphere, about 100 km below. These solid particles, often called 'tholins', have been currently investigated for many years by laboratory scientists and physics modellers. This paper assesses past research and results in different fields (elemental composition, optical constants, pyrolysis, particle size), hightlighting interests and questions aroused by these studies. It also presents the latest results and advances, and concludes with existing problems and future pathways.
Photochemistry is leading the chemical evolution in the Solar System. The VUV photolysis of organ... more Photochemistry is leading the chemical evolution in the Solar System. The VUV photolysis of organic compounds is easy to study in the laboratory, with monochromatic sources, but it is difficult to simulate the whole range of wavelengths corresponding to the most energetic part of the Solar radiation (<190nm). This is why the results obtained in laboratory are difficult to extrapolate
Solar UV radiation is a major source of energy to initiate chemical evolution towards complex org... more Solar UV radiation is a major source of energy to initiate chemical evolution towards complex organic structures, but it can also photodissociate the most elaborate molecules. Thus, Solar UV can erase the organic traces of past life on the surface of planets like Mars, or it can influence the production of extended sources(*) in comets. The VUV photolysis of organic
Several chlorohydrocarbons were detected by the SAM instrument after pyrolysis of the Rocknest sa... more Several chlorohydrocarbons were detected by the SAM instrument after pyrolysis of the Rocknest sample. The origin of these organics will be discussed.
Overview of results from Curiosity's Sample Analysis at Mars (SAM) investigation during the ... more Overview of results from Curiosity's Sample Analysis at Mars (SAM) investigation during the first 120 martian sols are summarized.
Titan s organic aerosols play a significant role in the physical properties of the atmosphere and... more Titan s organic aerosols play a significant role in the physical properties of the atmosphere and the subsequent meteorology the properties of the surface where they can have accumulated in significant amounts and in the cycle of the organic matter of the Saturn s satellite which is of primary importance from an astrobiological point of view However the amount of direct data dealing with the Titan s aerosols properties is quite low and the data recovered from the Cassini and the Huygens probes should significantly enhance our knowledge about these particles Except some spectral data that should provide morphological and some indirect compositional information on the aerosols the first in situ compositional data were recovered by the Aerosol Collector and Pyrolyser ACP experiment of the Huygens probe This experiment collected two distinct atmospheric samples over separate altitude ranges 130-35 km and 25-20 km respectively during the Huygens probe descent The samples were pyrolysed h...
In past times life might have occurred in Martian conditions milder than the present ones and lef... more In past times life might have occurred in Martian conditions milder than the present ones and left some remnants at the surface Even if this did not happen prebiotic molecules may have been be preserved that might be similar to the ones that prevailed on Earth surface some 3 5 to 4 billion years ago NASA s MSL09 rover will
Since the beginning of the space exploration, most of the many probes which have been sent to exp... more Since the beginning of the space exploration, most of the many probes which have been sent to explore other planetary atmospheres and surfaces carried instruments to determine their elemental, isotopic and molecular -inorganic as well as organic- compositions. As Mass Spectrometry (MS) and Gas Chromatography (GC) are powerful analytical techniques which fulfil the severe constraints of space instrumentation (mass, size, mechanical strength, automation and energy consumption), they have been the techniques the most frequently used for in situ chemical analysis of extraterrestrial environments, essentially Mars and Venus in the 70s and 80s. After 20 years and the investigation of Venus atmosphere by the Vega probe, they will be used again next year to investigate the atmosphere of a fascinating world : Titan Because of its composition (rich in organics) and density (similar to the Earth's one), the study of the atmosphere of Titan is of primary interest for understanding a reducin...
Origins of life and evolution of the biosphere : the journal of the International Society for the Study of the Origin of Life, 1998
Titan, the largest satellite of Saturn, has an atmosphere chiefly made up of N2 and CH4, and incl... more Titan, the largest satellite of Saturn, has an atmosphere chiefly made up of N2 and CH4, and including many organics. This atmosphere also partly consists of hazes and aerosol particles which shroud the surface of this satellite, giving it a reddish appearance. The aerosols observed in Titan's atmosphere are thought to be synthesized at high altitudes (>300 km) and fall to the surface. Varying with temperature profiles, condensation phenomena take place in the lower atmosphere, about 100 km below. These solid particles, often called 'tholins', have been currently investigated for many years by laboratory scientists and physics modellers. This paper assesses past research and results in different fields (elemental composition, optical constants, pyrolysis, particle size), hightlighting interests and questions aroused by these studies. It also presents the latest results and advances, and concludes with existing problems and future pathways.
Photochemistry is leading the chemical evolution in the Solar System. The VUV photolysis of organ... more Photochemistry is leading the chemical evolution in the Solar System. The VUV photolysis of organic compounds is easy to study in the laboratory, with monochromatic sources, but it is difficult to simulate the whole range of wavelengths corresponding to the most energetic part of the Solar radiation (<190nm). This is why the results obtained in laboratory are difficult to extrapolate
Solar UV radiation is a major source of energy to initiate chemical evolution towards complex org... more Solar UV radiation is a major source of energy to initiate chemical evolution towards complex organic structures, but it can also photodissociate the most elaborate molecules. Thus, Solar UV can erase the organic traces of past life on the surface of planets like Mars, or it can influence the production of extended sources(*) in comets. The VUV photolysis of organic
Several chlorohydrocarbons were detected by the SAM instrument after pyrolysis of the Rocknest sa... more Several chlorohydrocarbons were detected by the SAM instrument after pyrolysis of the Rocknest sample. The origin of these organics will be discussed.
Overview of results from Curiosity's Sample Analysis at Mars (SAM) investigation during the ... more Overview of results from Curiosity's Sample Analysis at Mars (SAM) investigation during the first 120 martian sols are summarized.
Titan s organic aerosols play a significant role in the physical properties of the atmosphere and... more Titan s organic aerosols play a significant role in the physical properties of the atmosphere and the subsequent meteorology the properties of the surface where they can have accumulated in significant amounts and in the cycle of the organic matter of the Saturn s satellite which is of primary importance from an astrobiological point of view However the amount of direct data dealing with the Titan s aerosols properties is quite low and the data recovered from the Cassini and the Huygens probes should significantly enhance our knowledge about these particles Except some spectral data that should provide morphological and some indirect compositional information on the aerosols the first in situ compositional data were recovered by the Aerosol Collector and Pyrolyser ACP experiment of the Huygens probe This experiment collected two distinct atmospheric samples over separate altitude ranges 130-35 km and 25-20 km respectively during the Huygens probe descent The samples were pyrolysed h...
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