The PROCESS experiment: amino and carboxylic acids under Mars-like surface UV radiation conditions in low-earth orbit

The search for organic molecules at the surface of Mars is a top priority of the next Mars exploration space missions: Mars Science Laboratory (NASA) and ExoMars (ESA). The detection of organic matter could provide information about the presence of a prebiotic chemistry or even biological activity on this planet. Therefore, a key step in interpretation of future data collected by these missions is to understand the preservation of organic matter in the martian environment. Several laboratory experiments have been devoted to quantifying and qualifying the evolution of organic molecules under simulated environmental conditions of Mars. However, these laboratory simulations are limited, and one major constraint is the reproduction of the UV spectrum that reaches the surface of Mars. As part of the PROCESS experiment of the European EXPOSE-E mission on board the International Space Station, a study was performed on the photodegradation of organics under filtered extraterrestrial solar electromagnetic radiation that mimics Mars-like surface UV radiation conditions. Glycine, serine, phthalic acid, phthalic acid in the presence of a mineral phase, and mellitic acid were exposed to these conditions for 1.5 years, and their evolution was determined by Fourier transform infrared spectroscopy after their retrieval. The results were compared with data from laboratory experiments. A 1.5-year exposure to Mars-like surface UV radiation conditions in space resulted in complete degradation of the organic compounds. Half-lives between 50 and 150?h for martian surface conditions were calculated from both laboratory and low-Earth orbit experiments. The results highlight that none of those organics are stable under low-Earth orbit solar UV radiation conditions.     

Astrobiology and habitability of Titan

Largest satellite of Saturn and the only in the solar system having a dense atmosphere, Titan is one of the key planetary bodies for astrobiological studies, due to several aspects. (i) Its analogies with planet Earth, in spite of much lower temperatures, with, in particular, a methane cycle on Titan analogous to the water cycle on Earth. (ii) The presence of an active organic chemistry, involving several of the key compounds of prebiotic chemistry. The recent data obtained from the Huygens instruments show that the complex organic matter in Titan’s low atmosphere is mainly concentrated in the aerosol particles. The formation of biologically interesting compounds may also occur in the deep water ocean, from the hydrolysis of complex organic material included in the chrondritic matter accreted during the formation of Titan. (iii) The possible emergence and persistence of Life on Titan. All ingredients which seem necessary for Life to appear and even develop – liquid water, organic matter and energy – are present on Titan. Consequently, it cannot be excluded that life may have emerged on or in Titan. In spite of the extreme conditions in this environment life may have been able to adapt and to persist. Many data are still expected from the Cassini-Huygens mission and future astrobiological exploration mission of Titan are now under consideration. Nevertheless, Titan already looks like another world, with an active organic chemistry, in the absence of permanent liquid water, on the surface: a natural laboratory for prebiotic-like chemistry.     

TARANIS—A Satellite Project Dedicated to the Physics of TLEs and TGFs

TARANIS “Tool for the Analysis of RAdiations from lightNIngs and Sprites” is a CNES satellite project dedicated to the study of impulsive transfers of energy between the Earth atmosphere and the space environment. Such impulsive transfers of energy, identified by the observation at ground and in space (rocket, balloons, FORMOSAT 2 satellite) of Transient Luminous Events (TLEs) and the detection on satellites (CGRO, RHESSI) of Terrestrial Gamma ray Flashes (TGFs), are likely to occur in other astrophysical environments as well. The TARANIS mission and instrumentation is presented. The way the TARANIS programme (associated ground-based and balloon-based measurements included) may answer questions about the physics of TLEs and TGFs is examined. The questions addressed include: TLEs and TGFs source regions, associated phenomena, transfers of energy between the radiation belts and the atmosphere, TLEs and TGFs generation mechanisms, input parameters to the modelling of the variation of the atmosphere and the electric circuit.     

Molecular Hydrogen

Observations of H₂ line emission in galactic and extragalactic environments obtained with the Infrared Space Observatory (ISO) are reviewed. The diagnostic capability of H₂ observations is illustrated. We discuss what one has learned about such diverse astrophysical sources as photon-dominated regions, shocks, young stellar objects, planetary nebulae and starburst galaxies from ISO observations of H₂ emission. In this context, we emphasise use of measured H₂ line intensities to infer important physical quantities such as the gas temperature, gas density and radiation field and we discuss the different possible excitation mechanisms of H₂. We also briefly consider future prospects for observation of H₂ from space and from the ground. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, The Netherlands, and the United Kingdom), and with the participation of ISAS and NASA.     

CIVA

CIVA (Comet Infrared and Visible Analyser) is an integrated set of imaging instruments, designed to characterize the 360^∘ panorama (CIVA-P) as seen from the Rosetta Lander Philae, and to study surface and subsurface samples (CIVA-M). CIVA-P is a panoramic stereo camera, while CIVA-M is an optical microscope coupled to a near infrared microscopic hyperspectral imager. CIVA shares a common Imaging Main Electronics (IME) with ROLIS. CIVA-P will characterize the landing site, with an angular sampling (IFOV) of 1.1 mrad: each pixel will image a 1 mm size feature at the distance of the landing legs, and a few metres at the local horizon. The panorama will be mapped by 6 identical miniaturized micro-cameras covering contiguous FOV, with their optical axis 60^∘ apart. Stereoscopic capability will be provided by an additional micro-camera, identical to and co-aligned with one of the panoramic micro-camera, with its optical axis displaced by 10 cm. CIVA-M combines two ultra-compact and miniaturised microscopes, one operating in the visible and one constituting an IR hyperspectral imaging spectrometer: they will characterize, by non-destructive analyses, the texture, the albedo, the molecular and the mineralogical composition of each of the samples provided by the Sample Drill and Distribution (SD2) system. For the optical microscope, the spatial sampling is 7 μm; for the IR, the spectral range (1–4 μm) and the spectral sampling (5 nm) have been chosen to allow identification of most minerals, ices and organics, on each pixel, 40 μm in size. After being studied by CIVA, the sample could be analysed by a subsequent experiment (PTOLEMY and/or COSAC). The process would be repeated for each sample obtained at different depths and/or locations.     

VLF electromagnetic waves observed onboard GEOS-1

This paper is concerned mainly with the information which can be extracted from frequency-time spectra in the VLF range. The instrument used is the correlator which has a good frequency resolution (50 Hz) and time resolution (30 ms) in one magnetic and one electric component simultaneously. By suitable computer analysis, it is possible for instance to distinguish between the two dominant electromagnetic emissions, hiss and chorus, as well as to display the complete spectra. This treatment is applied to the Survey periods, which are a fixed sequence of modes, repeated every hour on the hour in order to have reference data from GEOS analogous to many ground-based observatories. One result of this treatment obtained already is that hiss and chorus normally appear together, although one or the other may be dominating in intensity. The occurrence rate of these emissions in local time is also given.For continuous surveillance the filterbank data are used. There are 16 frequency filters supplying magnetic and electric amplitude at few different frequencies. Using these data, a storm sudden commencement can be followed with good time resolution (1 s), and an interesting correlation has been found in a few cases between the VLF signal amplitude and the cold plasma density (as measured by the active part of the S-300 experiment).     

Cosac, The Cometary Sampling and Composition Experiment on Philae

Comets are thought to preserve the most pristine material currently present in the solar system, as they are formed by agglomeration of dust particles in the solar nebula, far from the Sun, and their interiors have remained cold. By approaching the Sun, volatile components and dust particles are released forming the cometary coma. During the phase of Heavy Bombardment, 3.8--4 billion years ago, cometary matter was delivered to the Early Earth. Precise knowledge on the physico-chemical composition of comets is crucial to understand the formation of the Solar System, the evolution of Earth and particularly the starting conditions for the origin of life on Earth. Here, we report on the COSAC instrument, part of the ESA cometary mission Rosetta, which is designed to characterize, identify, and quantify volatile cometary compounds, including larger organic molecules, by in situ measurements of surface and subsurface cometary samples. The technical concept of a multi-column enantio-selective gas chromatograph (GC) coupled to a linear reflectron time-of-flight mass-spectrometer instrument is presented together with its realisation under the scientific guidance of the Max-Planck-Institute for Solar System Research in Katlenburg-Lindau, Germany. The instrument's technical data are given; first measurements making use of standard samples are presented. The cometary science community is looking forward to receive fascinating data from COSAC cometary in situ measurements in 2014.