Papers by Pascale Ehrenfreund
Experimental Astronomy, 2009
The Triple F (Fresh From the Fridge) mission, a Comet Nucleus Sample Return, has been proposed to... more The Triple F (Fresh From the Fridge) mission, a Comet Nucleus Sample Return, has been proposed to ESA's Cosmic Vision program. A sample return from a comet enables us to reach the ultimate goal of cometary research. Since comets are the least processed bodies in the solar system, the proposal goes far beyond cometary science topics (like the explanation of cometary activity) and delivers invaluable information about the formation of the solar system and the interstellar molecular cloud from which it formed. three locations on a cometary nucleus and return them cooled to Earth for analysis in the laboratory. The simple mission concept with a touch-andgo sampling by a single spacecraft was proposed as an M-class mission in collaboration with the Russian space agency ROSCOSMOS.
Small Grains and Large Aromatic Molecules
Chemistry in Space, 1990
Solid State Infrared Features: a Diagnostic Tool for Chemical Interactions Between Interstellar Gas and Grains
ESO Astrophysics Symposia, 1996
Infrared Properties of Isolated Water Ice
ESO Astrophysics Symposia, 1996
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Responsible Space Exploration and Use: Balancing Stakeholder Interests
New Space, 2013
An ISO View on Interstellar and Cometary Ice Chemistry
Composition and Origin of Cometary Materials, 1999
The ISO-SWS instrument offering a large wavelength coverage and a resolution well adapted to the ... more The ISO-SWS instrument offering a large wavelength coverage and a resolution well adapted to the solid phase has changed our knowledge of the physical-chemical properties of ices in space. The discovery of many new ice features was reported and the comparison with dedicated laboratory experiments allowed the determination of more accurate abundances of major ice components. The presence of CO2 ice has recently been confirmed with the SWS (Short Wavelength Spectrometer) as a dominant ice component of interstellar grain mantles. The bending mode of CO2 ice shows a particular triple-peak structure which provides first evidence for extensive ice segregation in the line-of-sight toward massive protostars. A comparison of interstellar and cometary ices using recent ISO data and ground-based measurements has revealed important similarities but also indicated that comets contain, beside pristine interstellar material, admixtures of processed material. The investigation of molecules in interstellar clouds is essential to reveal the link between dust in the interstellar medium and in the Solar System.
Astrobiology --- A Bridge Between Earth Science and Space Exploration
Astrobiology, the study of life in the universe, addresses, as an interdisciplinary science field... more Astrobiology, the study of life in the universe, addresses, as an interdisciplinary science field, many questions that are relevant for sustaining life on planet Earth---and in particular, the relationships between a planet and life, and how each affects the other.
Ice Chemistry in Space
Solid State Astrochemistry, 2003
Abstract In this chapter we review the current knowledge on ice chemistry in space. We describe t... more Abstract In this chapter we review the current knowledge on ice chemistry in space. We describe the basic processes of ice formation and destruction on interstellar grains and discuss the role of icy particles as catalysts in dense molecular clouds. In the following ...
International Journal of Astrobiology, 2014
Expose is a multi-user instrument for astrobiological and astrochemical experiments in space. Ins... more Expose is a multi-user instrument for astrobiological and astrochemical experiments in space. Installed at the outer surface of the International Space Station, it enables investigators to study the impact of the open space environment on biological and biochemical test samples. Two Expose missions have been completed so far, designated as Expose-E (Rabbow et al. 2012) and Expose-R (Rabbow et al. this issue). One of the space-unique environmental factors offered by Expose is full-spectrum, ultraviolet (UV)-rich electromagnetic radiation from the Sun. This paper describes and analyses how on Expose-R, access of the test samples to Solar radiation degraded during space exposure in an unpredicted way. Several windows in front of the Sun-exposed test samples acquired a brown shade, resulting in a reduced transparency in visible light, UV and vacuum UV (VUV). Post-flight investigations revealed the discolouration to be caused by a homogenous film of cross-linked organic polymers at the inside of the windows. The chemical signature varied per sample carrier. No such films were found on windows from sealed, pressurized compartments, or on windows that had been kept out of the Sun. This suggests that volatile compounds originating from the interior of the Expose facility were cross-linked and photo-fixed by Solar irradiation at the rear side of the windows. The origin of the volatiles was not fully identified; most probably there was a variety of sources involved including the biological test samples, adhesives, plastics and printed circuit boards. The outer surface of the windows (pointing into space) was chemically impacted as well, with a probable effect on the transparency in VUV. The reported analysis of the window contamination on Expose-R is expected to help the interpretation of the scientific results and offers possibilities to mitigate this problem on future missionsin particular Expose-R2, the direct successor of Expose-R.
Based on predictions of impact magnitude and cloud ejecta dynamics, we organized a SMART-1 ground... more Based on predictions of impact magnitude and cloud ejecta dynamics, we organized a SMART-1 ground-based observation campaign to perform coordinated measurements of the impact. Results from the coordinated multi-site campaign will be discussed.
From Molecular Clouds to the Origin of Life
Astrobiology, 2002
Contents: The search for large organic molecules in dense clouds. Molecules in protoplanetary dis... more Contents: The search for large organic molecules in dense clouds. Molecules in protoplanetary disks. Diffuse interstellar clouds. The evolution of organic molecules during solar system formation. Implications for the origin of life on Earth.
Life (Basel, Switzerland), 2014
The three main requirements for life as we know it are the presence of organic compounds, liquid ... more The three main requirements for life as we know it are the presence of organic compounds, liquid water, and free energy. Several groups of organic compounds (e.g., amino acids, nucleobases, lipids) occur in all life forms on Earth and are used as diagnostic molecules, i.e., biomarkers, for the characterization of extant or extinct life. Due to their indispensability for life on Earth, these biomarkers are also prime targets in the search for life on Mars. Biomarkers degrade over time; in situ environmental conditions influence the preservation of those molecules. Nonetheless, upon shielding (e.g., by mineral surfaces), particular biomarkers can persist for billions of years, making them of vital importance in answering questions about the origins and limits of life on early Earth and Mars. The search for organic material and biosignatures on Mars is particularly challenging due to the hostile environment and its effect on organic compounds near the surface. In support of life detect...
Cold Spring Harbor perspectives in biology, 2010
Astronomical observations have shown that carbonaceous compounds in the gas and solid state, refr... more Astronomical observations have shown that carbonaceous compounds in the gas and solid state, refractory and icy are ubiquitous in our and distant galaxies. Interstellar molecular clouds and circumstellar envelopes are factories of complex molecular synthesis. A surprisingly large number of molecules that are used in contemporary biochemistry on Earth are found in the interstellar medium, planetary atmospheres and surfaces, comets, asteroids and meteorites, and interplanetary dust particles. In this article we review the current knowledge of abundant organic material in different space environments and investigate the connection between presolar and solar system material, based on observations of interstellar dust and gas, cometary volatiles, simulation experiments, and the analysis of extraterrestrial matter. Current challenges in astrochemistry are discussed and future research directions are proposed.
Composition and Origin of Cometary Materials
We present results from the analysis of spectra of the fast rotating giant FK Comae Berenices, ob... more We present results from the analysis of spectra of the fast rotating giant FK Comae Berenices, obtained with the recently commissioned ESA-MUSICOS spectrograph at the INT and with the Aurelie spectrograph at the OHP. The Balmer lines broad emission is modelled as arising from structures extending up to 4 stellar radii. The absorption is modelled due to the presence of a shell of cold and dense gas (solar-like filaments), near the corotation radius, covering about 20% of the stellar disc. The extended emission is believed to arise in giant structures reminiscent of active loops or prominences. Time resolved Hα emission spectroscopy indicates that these structures undergo continuous microflaring. Based on data sets from May and November 1996 and May and June 1997, we describe different time scales for variability, from yearly rise of activity to hourly microflares. Based on observations with the ESA-MUSICOS spectrograph at the 2.5 m Isaac Newton Telescope, ING Observatory, Spain and w...
Sampling Extreme Life in the Desert: Geochemical Habitats and Biodiversity
Habitability in Mars Transient and Local environments: Field Analogue Sample Studies
Interstellar Organic Molecules: from Clouds to Solar Nebula
Although laboratory experiments involving energetic processing of simple molecules were able to r... more Although laboratory experiments involving energetic processing of simple molecules were able to reproduce many of the biomolecules that are the building blocks of living organisms impacts of comets and asteroids could have delivered large amounts of organic matter to the early Earth. Volatile cometary matter appears to retain a significant interstellar signature; observations of recent bright comets indicate that they
Reactivity Analyzer for Soil, Ices, and Regolith (RASIR)
ABSTRACT The Reactivity Analyzer for Soil, Ices, and Regolith (RASIR) is an integrated microanaly... more ABSTRACT The Reactivity Analyzer for Soil, Ices, and Regolith (RASIR) is an integrated microanalytical system designed to simultaneously measure the organic content and chemical reactivity/toxicity levels of martian surface samples.
PEX's Role in Opening Up the Solar System for Scientific Exploration
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Papers by Pascale Ehrenfreund