113 research outputs found
The Signs of Life Detector (SOLID): An Instrument to Detect Molecular Biosignatures on Mars
The case for life on Mars grows stronger. Investigations at Gale Crater by Curiosity have revealed fine-grained sedimentary rocks inferred to represent an ancient lake environment suited to support life. In addition, Curiosity tentatively found a heterogeneous distribution of organic carbon within these sediments, consistent with the detection of native organic C in Mars meteorites. Furthermore, modern potentially habitable environments have been recognized on Mars including the N. Polar region visited by Phoenix, gully features suggesting modern water flows, and RSLs that occur seasonally suggest liquid processes. The time is ripe for missions to Mars incorporating a search for biochemical evidence of life
The Icebreaker Mission to Search for Life on Mars
The search for evidence of life on Mars is the ultimate motivation for its scientific exploration. The results from the Phoenix mission indicate that the high N. latitude ice-rich regolith at low elevations is likely to be a recently habitable place on Mars [Stoker et al., 2010]. The near-surface ice likely provided adequate water activity during periods of high obliquity, 3 to 10 Myr ago. Carbon dioxide and nitrogen are present in the atmosphere, and nitrates may be present in the soil. Together with iron in basaltic rocks and perchlorate in the soil they provide carbon and energy sources, and oxidative power to drive metabolism. Furthermore, the presence of organics is possible, as thermally reactive perchlorate would have prevented their detection by Viking and Phoenix. The Mars Icebreaker Life mission [McKay et al., 2013] focuses on the following science goals: (1) Search for biomolecular evidence of life; (2) Search for organic matter from either exogeneous or endogeneous sources using methods that are not effected by the presence of perchlorate; (3) Characterize oxidative species that produced reactivity of soils seen by Viking; and 4) Assess the habitability of the ice bearing soils. The Icebreaker Life payload (Figure 1) includes a 1-m rotary percussive drill that brings cuttings samples to the surface where they are delivered to three instruments (Fig. 1), the Signs of Life Detector (SOLID) [Parro et al., 2011] for biomolecular analysis, Laser Desorption Mass Spectrometer (LDMS) [??? 2015]) for broad spectrum organic analysis, and Wet Chemistry Laboratory (WCL) [Hecht et al., 2009] for detecting soluble species of nutrients and reactive oxidants. The Icebreaker payload fits on the Phoenix spacecraft and can land at the well-characterized Phoe-nix landing site in 2020 in a Discovery-class mission
Oxalate formation under the hyperarid conditions of the Atacama desert as a mineral marker to provide clues to the source of organic carbon on Mars
In this study, we report the detection and characterization of the organic minerals weddellite
(CaC2O4 · 2H2O) and whewellite (CaC2O4 · H2O) in the hyperarid, Mars-like conditions of the Salar Grande,
Atacama desert, Chile. Weddellite and whewellite are commonly of biological origin on Earth and have great
potential for preserving records of carbon geochemistry and possible biological activity on Mars if they
are present there. Weddellite and whewellite have been found as secondary minerals occurring inside the
lower detrital unit that fills the Salar Grande basin. The extremely low solubility of most oxalate minerals
inhibits detection of oxalate by ion chromatography (IC). Crystalline oxalates, including weddellite and
whewellite, were detected by X-ray diffraction (XRD). The association of weddellite with surface biota and its
presence among subsurface detrital materials suggest the potential of a biological origin for Salar Grande
weddellite and whewellite. In this regard, biological activity is uniquely capable of concentrating oxalates
at levels detectable by XRD. The complementary detection of oxalate-bearing phases through IC in the upper
halite-rich unit suggests the presence of a soluble oxalate phase in the basin that is not detected by XRD.
The formation, transport, and concentration of oxalate in the Salar Grande may provide a geochemical
analogue for oxalate-bearing minerals recently suggested to exist on Mars
Abordagem de uma Paciente com Fibrilaçao Atrial e Insuficiência CardÃaca Tratada com Ablaçao do Nó Atrioventricular e Marcapasso MultissÃtio
Paciente do sexo feminino, com58anos, portadora de cardiomiopatia dilatada, acompanhada desde 1984 por apresentar insuficiência cardÃaca e hipertensao arterial. Na evoluçao, apresentou bloqueio de ramo esquerdo e fibrilaçao atrial. No final de 1999, mesmo com a medicaçao adequada e otimizada para insuficiência cardÃaca, apresentava-se em grau funcional IV e as internaçoes hospitalares haviam se tornando cada vez mais freqüentes. Em janeiro de 2000, optou-se pela ablaçao do nó atrioventricular e pelo implante de um marcapasso endocárdico bifocal multissÃtio em ventrÃculo direito. Desde entao vem evoluindo bem, com menor número de medicamentos e raras internaçoes
Abordagem de uma Paciente com Fibrilaçao Atrial e Insuficiência CardÃaca Tratada com Ablaçao do Nó Atrioventricular e Marcapasso MultissÃtio
Paciente do sexo feminino, com58anos, portadora de cardiomiopatia dilatada, acompanhada desde 1984 por apresentar insuficiência cardÃaca e hipertensao arterial. Na evoluçao, apresentou bloqueio de ramo esquerdo e fibrilaçao atrial. No final de 1999, mesmo com a medicaçao adequada e otimizada para insuficiência cardÃaca, apresentava-se em grau funcional IV e as internaçoes hospitalares haviam se tornando cada vez mais freqüentes. Em janeiro de 2000, optou-se pela ablaçao do nó atrioventricular e pelo implante de um marcapasso endocárdico bifocal multissÃtio em ventrÃculo direito. Desde entao vem evoluindo bem, com menor número de medicamentos e raras internaçoes
Transitory Microbial Habitat in the Hyperarid Atacama Desert
Traces of life are nearly ubiquitous on Earth. However, a central unresolved question is whether these traces always indicate an active microbial community or whether, in extreme environments, such as hyperarid deserts, they instead reflect just dormant or dead cells. Although microbial biomass and diversity decrease with increasing aridity in the Atacama Desert, we provide multiple lines of evidence for the presence of an at times metabolically active, microbial community in one of the driest places on Earth. We base this observation on four major lines of evidence: a physico-chemical characterization of the soil habitability after an exceptional rain event, identified biomolecules indicative of potentially active cells [e.g., presence of ATP, phospholipid fatty acids (PLFAs), metabolites, and enzymatic activity], measurements of in situ replication rates of genomes of uncultivated bacteria reconstructed from selected samples, and microbial community patterns specific to soil parameters and depths. We infer that the microbial populations have undergone selection and adaptation in response to their specific soil microenvironment and in particular to the degree of aridity. Collectively, our results highlight that even the hyperarid Atacama Desert can provide a habitable environment for microorganisms that allows them to become metabolically active following an episodic increase in moisture and that once it decreases, so does the activity of the microbiota. These results have implications for the prospect of life on other planets such as Mars, which has transitioned from an earlier wetter environment to today's extreme hyperaridity. [Abstract copyright: Copyright © 2018 the Author(s). Published by PNAS.
Joint Europa Mission (JEM): a multi-scale study of Europa to characterize its habitability and search for extant life
Europa is the closest and probably the most promising target to search for extant life in the Solar System, based on complementary evidence that it may fulfil the key criteria for habitability: the Galileo discovery of a sub-surface ocean; the many indications that the ice shell is active and may be partly permeable to transfer of chemical species, biomolecules and elementary forms of life; the identification of candidate thermal and chemical energy sources necessary to drive a metabolic activity near the ocean floor. In this article we are proposing that ESA collaborates with NASA to design and fly jointly an ambitious and exciting planetary mission, which we call the Joint Europa Mission (JEM), to reach two objectives: perform a full characterization of Europa's habitability with the capabilities of a Europa orbiter, and search for bio-signatures in the environment of Europa (surface, subsurface and exosphere) by the combination of an orbiter and a lander. JEM can build on the advanced understanding of this system which the missions preceding JEM will provide: Juno, JUICE and Europa Clipper, and on the Europa lander concept currently designed by NASA (Maize, report to OPAG, 2019). We propose the following overarching goals for our Joint Europa Mission (JEM): Understand Europa as a complex system responding to Jupiter system forcing, characterize the habitability of its potential biosphere, and search for life at its surface and in its sub-surface and exosphere. We address these goals by a combination of five Priority Scientific Objectives, each with focused measurement objectives providing detailed constraints on the science payloads and on the platforms used by the mission. The JEM observation strategy will combine three types of scientific measurement sequences: measurements on a high-latitude, low-altitude Europan orbit; in-situ measurements to be performed at the surface, using a soft lander; and measurements during the final descent to Europa's surface. The implementation of these three observation sequences will rest on the combination of two science platforms: a soft lander to perform all scientific measurements at the surface and sub-surface at a selected landing site, and an orbiter to perform the orbital survey and descent sequences. We describe a science payload for the lander and orbiter that will meet our science objectives. We propose an innovative distribution of roles for NASA and ESA; while NASA would provide an SLS launcher, the lander stack and most of the mission operations, ESA would provide the carrier-orbiter-relay platform and a stand-alone astrobiology module for the characterization of life at Europa's surface: the Astrobiology Wet Laboratory (AWL). Following this approach, JEM will be a major exciting joint venture to the outer Solar System of NASA and ESA, working together toward one of the most exciting scientific endeavours of the 21st century: to search for life beyond our own planet
VADER: Probing the Dark Side of Dimorphos with LICIACube LUKE
The ASI cubesat LICIACube has been part of the first planetary defense mission DART, having among its scopes to complement the DRACO images to better constrain the Dimorphos shape. LICIACube had two different cameras, LEIA and LUKE, and to accomplish its goal, it exploited the unique possibility of acquiring images of the Dimorphos hemisphere not seen by DART from a vantage point of view, in both time and space. This work is indeed aimed at constraining the tridimensional shape of Dimorphos, starting from both LUKE images of the nonimpacted hemisphere of Dimorphos and the results obtained by DART looking at the impacted hemisphere. To this aim, we developed a semiautomatic Computer Vision algorithm, named VADER, able to identify objects of interest on the basis of physical characteristics, subsequently used as input to retrieve the shape of the ellipse projected in the LUKE images analyzed. Thanks to this shape, we then extracted information about the Dimorphos ellipsoid by applying a series of quantitative geometric considerations. Although the solution space coming from this analysis includes the triaxial ellipsoid found by using DART images, we cannot discard the possibility that Dimorphos has a more elongated shape, more similar to what is expected from previous theories and observations. The result of our work seems therefore to emphasize the unique value of the LICIACube mission and its images, making even clearer the need of having different points of view to accurately define the shape of an asteroid.This work was supported by the Italian Space Agency (ASI) within the LICIACube project (ASI-INAF agreement AC No. 2019-31-HH.0) and by the DART mission, NASA contract 80MSFC20D0004
ELT high resolution spectrograph: phase-A software architecture study
High resolution spectroscopy has been considered of a primary importance to exploit the main scientific cases foreseen for ESO ELT, the Extremely Large Telescope, the future largest optical-infrared telescope in the world. In this context ESO commissioned a Phase-A feasibility study for the construction of a high resolution spectrograph for the ELT, tentatively named HIRES. The study, which lasted 1.5 years, started on March 2016 and was completed with a review phase held at Garching ESO headquarters with the aim to assess the scientific and technical feasibility of the proposed instrument. One of the main tasks of the study is the architectural design of the software covering all the aspects relevant to control an astronomical instrument: from observation preparation through instrument hardware and detectors control till data reduction and analysis. In this paper we present the outcome of the Phase-A study for the proposed HIRES software design highlighting its peculiarities, critical areas and performance aspects for the whole data flow. The End-toEnd simulator, a tool already capable of simulating HIRES end products and currently being used to drive some design decision, is also shortly described
- …