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At least 307 records · Page 17

Organism/Organic Exposure to Orbital Stresses (OOREOS) Satellite: Radiation Exposure in LEO and Supporting Laboratory Studies

We will present the results from the exposure of the metalloporphyrin iron tetraphenylporphyrin chloride (FeTPPCI), anthraufin (C(sub 14)H(sub 8)(O sub 4) (Anth) and Isoviolanthrene (C(sub 34H sub 18) (IVA) to the outher space environment, measured in situ aboard the Organism/Organic Exposure to Orbital Stresses nanosatellite. The compounds were exposed for a period of 17 months (3700 hours of direct solar exposure) including broad-spectrum solar radiation (approx. 122 nm to the near infrared). The organic films are enclosed in hermetically sealed sample cells that contain one of four astrobiologically relevant microenvironments. Transmission spectra (200-1000 nm) were recorded for each film, at first daily and subsequently every 15 days, along with a solar spectrum and the dark response of the detector array. In addition to analysis via UV-Vis spectroscopy, the laboratory controls were also monitored via infrared and far-UV spectroscopy. The results presented will include the finding that the FeTPPCI and IVA organic films in contact with a humid headspace gas (0.8-2.3%) exhibit faster degradation times, upon irradiation, in comparison with identical films under dry headspaces gases, whereas the Anth thin film exhibited a higher degree of photostability. In the companion laboratory experiments, simulated solar exposure of FeTPI films in contact with either Ar or CO(sub -2):O(sub -2):Ar (10:0.01:1000) headspace gas results in growth of a band in the films infrared spectra at 1961 cm(sup 1). Our assignment of this new spectral feature and the corresponding rational will be presented. The relevance of O/OREOS findings to planetary science, biomarker research, and the photostability of organic materials in astrobiologically relevant environments will also be discussed.

Radiation Exposure↗

How Dusty Is Alpha Centauri? Excess or Non-excess over the Infrared Photospheres of Main-sequence Stars

Context. Debris discs around main-sequence stars indicate the presence of larger rocky bodies. The components of the nearby, solar-type binary Centauri have metallicities that are higher than solar, which is thought to promote giant planet formation. Aims. We aim to determine the level of emission from debris around the stars in the Cen system. This requires knowledge of their photospheres.Having already detected the temperature minimum, Tmin, of CenA at far-infrared wavelengths, we here attempt to do the same for the moreactive companion Cen B. Using the Cen stars as templates, we study the possible eects that Tmin may have on the detectability of unresolveddust discs around other stars. Methods.We used Herschel-PACS, Herschel-SPIRE, and APEX-LABOCA photometry to determine the stellar spectral energy distributions in thefar infrared and submillimetre. In addition, we used APEX-SHeFI observations for spectral line mapping to study the complex background around Cen seen in the photometric images. Models of stellar atmospheres and of particulate discs, based on particle simulations and in conjunctionwith radiative transfer calculations, were used to estimate the amount of debris around these stars. Results. For solar-type stars more distant than Cen, a fractional dust luminosity fd LdustLstar 2 107 could account for SEDs that do not exhibit the Tmin eect. This is comparable to estimates of fd for the Edgeworth-Kuiper belt of the solar system. In contrast to the far infrared,slight excesses at the 2:5 level are observed at 24 m for both CenA and B, which, if interpreted as due to zodiacal-type dust emission, wouldcorrespond to fd (13) 105, i.e. some 102 times that of the local zodiacal cloud. Assuming simple power-law size distributions of the dustgrains, dynamical disc modelling leads to rough mass estimates of the putative Zodi belts around the Cen stars, viz.4106 M$ of 4 to 1000 msize grains, distributed according to n(a) a3:5. Similarly, for filled-in Tmin emission, corresponding Edgeworth-Kuiper belts could account for103 M$ of dust. Conclusions. Our far-infrared observations lead to estimates of upper limits to the amount of circumstellar dust around the stars CenA and B.Light scattered andor thermally emitted by exo-Zodi discs will have profound implications for future spectroscopic missions designed to searchfor biomarkers in the atmospheres of Earth-like planets. The far-infrared spectral energy distribution of Cen B is marginally consistent with thepresence of a minimum temperature region in the upper atmosphere of the star. We also show that an Cen A-like temperature minimum mayresult in an erroneous apprehension about the presence of dust around other, more distant stars.

metallicities↗

Development of an Autonomous, Dual Chamber Bioreactor for the Growth of 3-Dimensional Epithelial-Stromal Tissues in Microgravity

We are developing a novel, autonomous bioreactor that can provide for the growth and maintenance in microgravity of 3‐D organotypic epithelial‐stromal cultures that require an air‐liquid interface. These complex 3‐D tissue models accurately represent the morphological features, differentiation markers, and growth characteristics observed in normal human epithelial tissues, including the skin, esophagus, lung, breast, pancreas, and colon. However, because of their precise and complex culture requirements, including that of an air‐liquid interface, these 3‐D models have yet to be utilized for life sciences research aboard the International Space Station. The development of a bioreactor for these cultures will provide the capability to perform biological research on the ISS using these realistic, tissue‐like human epithelial‐stromal cell models and will contribute significantly to advances in fundamental space biology research on questions regarding microgravity effects on normal tissue development, aging, cancer, and other disease processes. It will also allow for the study of how combined stressors, such as microgravity with radiation and nutritional deficiencies, affect multiple biological processes and will provide a platform for conducting countermeasure investigations on the ISS without the use of animal models. The technology will be autonomous and consist of a cell culture chamber that provides for air‐liquid, liquid‐liquid, and liquid‐air exchanges within the chambers while maintaining the growth and development of the biological samples. The bioreactor will support multiple tissue types and its modular design will provide for incorporation of add‐on capabilities such as microfluidics drug delivery, media sampling, and in situ biomarker analysis. Preliminary flight testing of the hardware will be conducted on a parabolic platform through NASA's Flight Opportunities Program.

Patel, Zarana S.↗

Ames Coronagraph Experiment: Enabling Missions to Directly Image Exoplanets

Technology to find biomarkers and life on other worlds is rapidly maturing. If there is a habitable planet around the nearest star, we may be able to detect it this decade with a small satellite mission. In the 2030 decade, we will likely know if there is life in our Galactic neighborhood (1000 nearest stars). The Ames Coronagraph Experiment is developing coronagraphic technologies to enable such missions.

coronagraph↗

Risk of Oxidative Damage to Bone from Increased Iron Stores During Space Flight

Iron stores are increased secondary to neocytolysis of red blood cells and a high dietary intake of iron during space flight. This raises concerns about the risk of excess iron causing oxidative damage in many tissues, including bone. Biomarkers of iron status, oxidative damage, and bone resorption during space flight were analyzed for 23 (16 M/7 F) International Space Station crewmembers as part of the Nutrition SMO project. Up to 5 in-flight blood samples and 24-h urine pools were collected over the course of the 4-6 month missions. Serum iron increased slightly during space flight and was decreased at landing (P < 0.0004). An increase in serum ferritin early in flight (217% in women and 68% in men, P < 0.0004), returning to preflight concentrations at landing, and a decrease in transferrin and transferrin receptors during flight indicated that a transient increase in iron stores occurred. No inflammatory response was observed during flight. The oxidative damage markers 8-hydroxy-2'-deoxyguanosine and prostaglandin F(sub 2(alpha)) were positively correlated (both P < 0.001) with serum ferritin. A greater area under the curve for ferritin during flight was correlated with greater changes in bone mineral density of several bone regions after flight (1). In a separate study (2), a ground-based investigation was conducted that examined the combined effects of radiation exposure and iron overload on sensitivity to radiation injury in several physiological systems in 12-wk male Sprague-Dawley rats. The rats were acclimated to an adequate iron diet (45 mg iron (ferric citrate)/kg diet) for 3 wk and then assigned to one of four groups: adequate iron (Fe) diet/no radiation, adequate Fe diet/ radiation, moderately high Fe diet (650 mg Fe (ferric citrate)/kg diet)/no radiation, and moderately high Fe diet/radiation. Animals remained on the assigned diet for 4 wk. Starting on day 14 of experimental diet treatment, animals were exposed to a fractionated dose (0.375 Gy) of Cs-137 every other day (3 Gy total dose). On day 29 (24 h after last radiation exposure), animals were euthanized. Oxidative stress markers in the liver, bone, eyes, and serum were assessed. There was evidence that the iron diet contributed to DNA damage as well as radiation exposure in the liver, eyes, and bone. Together, the results suggest that increased iron stores do constitute a risk factor for oxidative damage and bone resorption, during space flight and on Earth. Funded by the Human Health and Countermeasures Element of the NASA Human Research Program.

Zwart, S. R.↗

Update of Bisphosphonate Flight Experiment

Elevated bone resorption is a hallmark of human spaceflight and bed rest indicating that elevated remodeling is a major factor in the etiology of space flight bone loss. In a collaborative effort between the NASA and JAXA space agencies, we are testing whether an antiresorptive drug would provide additional benefit to in-flight exercise to ameliorate bone loss and hypercalciuria during long-duration spaceflight. Measurements of bone loss include DXA, QCT, pQCT, urinary and blood biomarkers. We have completed analysis of R+1year data from 7 crewmembers treated with alendronate during flight, as well as immediate post flight (R+<2wks) data from 6 of 10 concurrent controls without treatment. The treated astronauts used the Advanced Resistive Exercise Device (ARED) during their missions. The purpose of this report is twofold: 1) to report the results of inflight, post flight and one year post flight bone measures compared with available controls with and without the use of ARED; and 2) to discuss preliminary data on concurrent controls. The figure below compares the BMD changes in ISS crewmembers exercising with and without the current ARED protocol and the alendronate treated crewmembers also using the ARED. This shows that the use of ARED prevents about half the bone loss seen in early ISS crewmembers and that the addition of an antiresorptive provides additional benefit. Resorption markers and urinary Ca excretion are not impacted by exercise alone but are significantly reduced with antiresorptive treatment. Bone measures for treated subjects, 1 year after return from space remain at or near baseline. DXA data for the 6 concurrent controls using the ARED device are similar to DXA data shown in the figure below. QCT data for these six indicate that the integral data are consistent with the DXA data, i.e., comparing the two control groups suggests significant but incomplete improvement in maintaining BMD using the ARED protocol. Biochemical data of the concurrent control group await sample return and analysis. The preliminary conclusion is that an antiresorptive may be an effective adjunct to exercise during long-duration spaceflight.

LeBlanc, A.↗

Toxicity of Mineral Dusts and a Proposed Mechanism for the Pathogenesis of Particle-Induced Lung Diseases

Humans will set foot on the moon again. The lunar surface has been bombarded for 4 billion years by micrometeoroids and cosmic radiation, creating a layer of fine dust having a potentially reactive particle surface. To investigate the impact of surface reactivity (SR) on the toxicity of particles, and in particular, lunar dust (LD), we ground 2 Apollo 14 LD samples to increase their SR and compare their toxicity with those of unground LD, TiO2 and quartz. Intratracheally instilled at 0, 1, 2.5, or 7.5 mg/rat, all dusts caused dose-dependent increases in pulmonary lesions, and enhancement of biomarkers of toxicity assessed in bronchoalveolar lavage fluids (BALF). The toxicity of LD was greater than that of TiO2 but less than that of quartz. Three LDs differed 14-fold in SR but were equally toxic; quartz had the lowest SR but was most toxic. These results show no correlation between particle SR and toxicity. Often pulmonary toxicity of a dust can be attributed to oxidative stress (OS). We further observed dose-dependent and dustcytotoxicity- dependent increases in neutrophils. The oxidative content per BALF cell was also directly proportional to both the dose and cytotoxicity of the dusts. Because neutrophils are short-lived and release of oxidative contents after they die could initiate and promote a spectrum of lesions, we postulate a general mechanism for the pathogenesis of particle-induced diseases in the lung that involves chiefly neutrophils, the source of persistent endogenous OS. This mechanism explains why one dust (e.g., quartz or nanoparticles) is more toxic than another (e.g., micrometer-sized TiO2), why dust-induced lesions progress with time, and why lung cancer occurs in rats but not in mice and hamsters exposed to the same duration and concentration of dust.

Lam, C.‐W.↗

The O/OREOS Mission - Astrobiology in Low Earth Orbit

The O/OREOS (Organism/Organic Exposure to Orbital Stresses) nanosatellite is the first science demonstration spacecraft and flight mission of the NASA Astrobiology Small- Payloads Program (ASP). O/OREOS was launched successfully on November 19, 2010, to a high-inclination (72 deg), 650-km Earth orbit aboard a US Air Force Minotaur IV rocket from Kodiak, Alaska. O/OREOS consists of 3 conjoined cubesat (each 1000 cu cm) modules: (i) a control bus; (ii) the Space Environment Survivability of Living Organisms (SESLO) experiment; and (iii) the Space Environment Viability of Organics (SEVO) experiment. Among the innovative aspects of the O/OREOS mission are a real-time analysis of the photostability of organics and biomarkers and the collection of data on the survival and metabolic activity for microorganisms at 3 times during the 6-month mission. We report on the spacecraft characteristics, payload capabilities, and present operational phase and flight data from the O/OREOS mission. The science and technology rationale of O/OREOS supports NASA0s scientific exploration program by investigating the local space environment as well as space biology relevant to Moon and Mars missions. It also serves as a precursor for experiments on small satellites, the International Space Station (ISS), future free-flyers and lunar surface exposure facilities.

Spectroscopy↗

A Search for Amino Acids and Nucleobases in the Martian Meteorite Roberts Massif 04262 Using Liquid Chromatography-Mass Spectrometry

The investigation into whether Mars contains signatures of past or present life is of great interest to science and society. Amino acids and nucleobases are compounds that are essential for all known life on Earth and are excellent target molecules in the search for potential Martian biomarkers or prebiotic chemistry. Martian meteorites represent the only samples from Mars that can be studied directly in the laboratory on Earth. Here, we analyzed the amino acid and nucleobase content of the shergottite Roberts Massif (RBT) 04262 using liquid chromatography-mass spectrometry. We did not detect any nucleobases above our detection limit in formic acid extracts; however, we did measure a suite of protein and nonprotein amino acids in hot-water extracts with high relative abundances of beta-alanine and gamma-amino-eta-butyric acid. The presence of only low (to absent) levels of several proteinogenic amino acids and a lack of nucleobases suggest that this meteorite fragment is fairly uncontaminated with respect to these common biological compounds. The distribution of straight-chained amine-terminal eta-omega-amino acids in RBT 04262 resembled those previously measured in thermally altered carbonaceous meteorites. A carbon isotope ratio of -24(0/00) +/- 6(0/00) for beta-alanine in RBT 04262 is in the range of reduced organic carbon previously measured in Martian meteorites (Steele et al. 2012). The presence of eta-omega-amino acids may be due to a high temperature Fischer-Tropschtype synthesis during igneous processing on Mars or impact ejection of the meteorites from Mars, but more experimental data are needed to support these hypotheses.

Laboratory analysis↗

Physiological Health Challenges for Human Missions to Mars

During the next decades, manned space missions are expected to be aiming at the Lagrange points, near Earth asteroids, and Mars flyby and/or landing. The question is therefore: Are we ready to go? To answer this with a yes, we are currently using the International Space Station to develop an integrated human physiological countermeasure suite. The integrated countermeasure suite will most likely encounter: 1) Exercise devices for aerobic, dynamic and resistive exercise training; 2) sensory‐motor computer training programs and anti‐motion sickness medication for preparing EVAs and G‐transitions; 3) lower limb bracelets for preventing and/or treating the VIIP (vision impairment and intracranial pressure) syndrome; 4) nutritional components for maintenance of bone, muscle, the cardiovascular system and preventing oxidative stress and damage and immune deficiencies (e. g. omega‐3 fatty acids, PRO/K, anti‐oxidants and less salt and iron); 5) bisphosphonates for preventing bone degradation.; 6) lower body compression garment and oral salt and fluid loading for landing on a planetary surface to combat orthostatic intolerance; 7) laboratory analysis equipment for individualized monitoring of biomarkers in blood, urine and saliva for estimation of health status in; 8) advanced ultrasound techniques for monitoring bone and cardiovascular health; and 9) computer modeling programs for individual health status assessments of efficiency and subsequent adjustments of countermeasures. In particular for future missions into deep space, we are concerned with the synergistic effects of weightlessness, radiation, operational constraints and other spaceflight environmental factors. Therefore, increased collaboration between physiological, behavioral, radiation and space vehicle design disciplines are strongly warranted. Another venue we are exploring in NASA's Human Research Program is the usefulness of artificial gravity for mitigating the health risks of long duration weightlessness.

Norsk, Peter↗

Combinatorial Multidomain Mesoporous Chips and a Method for Fractionation, Stabilization, and Storage of Biomolecules

A new fractionation device shows desirable features for exploratory screening and biomarker discovery. The constituent MSCs may be tailored for desired pore sizes and surface properties and for the sequestration and enrichment of extremely low abundant protein and peptides in desired ranges of the mass/charge spectrum. The MSCs are effective in yielding reproducible extracts from complex biological samples as small as 10 microliter in a time as short as 30 minutes. They are inexpensive to manufacture, and allow for scaled up production to attain the simultaneous processing of a large number of samples. The MSCs are multiplexed, label-free diagnostic tools with the potential of biological recognition moiety modification for enhanced specificity. The MSCs may store, protect and stabilize biological fluids, enabling the simplified and cost-effective collection and transportation of clinical samples. The MSC-based device may serve as a diagnostic tool to complement histopathology, imaging, and other conventional clinical techniques. The MSCs mediated identification of disease-specific protein signatures may help in the selection of personalized therapeutic combinations, in the real-time assessment of therapeutic efficacy and toxicity, and in the rational modulation of therapy based on the changes in the protein networks associated with the prognosis and the drug resistance of the disease.

Ferrari, Mauro↗

Omics Research on the International Space Station

The International Space Station (ISS) is an orbiting laboratory whose goals include advancing science and technology research. Completion of ISS assembly ushered a new era focused on utilization, encompassing multiple disciplines such as Biology and Biotechnology, Physical Sciences, Technology Development and Demonstration, Human Research, Earth and Space Sciences, and Educational Activities. The research complement planned for upcoming ISS Expeditions 45&46 includes several investigations in the new field of omics, which aims to collectively characterize sets of biomolecules (e.g., genomic, epigenomic, transcriptomic, proteomic, and metabolomic products) that translate into organismic structure and function. For example, Multi‐Omics is a JAXA investigation that analyzes human microbial metabolic cross‐talk in the space ecosystem by evaluating data from immune dysregulation biomarkers, metabolic profiles, and microbiota composition. The NASA OsteoOmics investigation studies gravitational regulation of osteoblast genomics and metabolism. Tissue Regeneration uses pan‐omics approaches with cells cultured in bioreactors to characterize factors involved in mammalian bone tissue regeneration in microgravity. Rodent Research‐3 includes an experiment that implements pan‐omics to evaluate therapeutically significant molecular circuits, markers, and biomaterials associated with microgravity wound healing and tissue regeneration in bone defective rodents. The JAXA Mouse Epigenetics investigation examines molecular alterations in organ specific gene expression patterns and epigenetic modifications, and analyzes murine germ cell development during long term spaceflight. Lastly, Twins Study ("Differential effects of homozygous twin astronauts associated with differences in exposure to spaceflight factors"), NASA's first foray into human omics research, applies integrated analyses to assess biomolecular responses to physical, physiological, and environmental stressors associated with spaceflight.

Love, John↗

A Simple and Sensitive LC-MS/MS Method for the Determination of Free 8-Hydroxy-2'-Deoxyguanosine in Human Urine

Urinary free 8-hydroxy-2'-deoxyguanosine (8OHdG), an oxidized product of DNA, and is frequently chosen as a biomarker of oxidative stress in humans, including studies of oxidative DNA damage during space flight. It is challenging to accurately and efficiently quantify urinary free 8OHdG in large scale human studies. LC-MS/MS is emerging as a preferable analytical technique owing its high sensitivity, selectivity and efficiency, compared to some traditional methods such as ELISA and HPLC. A simple and sensitive LC-MS/MS method has been developed for the determination of free 8OHdG in human urine. Sample preparation was done by solid phase extraction with a Waters Oasis HLB 96 well plate. A Waters Alliance 2795 HT Separation Module combined with a Quattro Micro tandem mass spectrometer was used as the LC-MS/MS system. The runtime of one injection can be less than 5 minutes using a reversed phase C18 column and an isocratic flow of methanol/water. ESI positive ions were quantified in the multiple reaction modes (MRM) using m/z 284 yields 168 for 8OHdG and m/z 289 yields173 for stable isotope labeled internal standard [(15)N5] 8OHdG. With this method for 8OHdG, a lower limit of quantitation of 1.0 nM (0.28 ng/mL) has been achieved using 100 microliter urine sample. The analytical range is between 1.0 and 100 nM with a correlation coefficient greater than or equal to 0.99. Good reproducibility can be obtained with intra-assay and inter-assay CVs less than or equal to 10% for 8OHdG spiked urine QC samples. This method can be used in high-throughput routine analysis of free 8OHdG in human urine.

Wang, Zuwei↗

New Insights into Amino Acid Preservation in the Early Oceans Using Modern Analytical Techniques

Protein- and non-protein-amino acids likely occupied the oceans at the time of the origin and evolution of life. Primordial soup-, hydrothermal vent-, and meteoritic-processes likely contributed to this early chemical inventory. Prebiotic synthesis and carbonaceous meteorite studies suggest that non-protein amino acids were likely more abundant than their protein-counterparts. Amino acid preservation before abiotic and biotic destruction is key to biomarker availability in paleoenvironments and remains an important uncertainty. To constrain primitive amino acid lifetimes, a 1992 archived seawater/beach sand mixture was spiked with D,L-alanine, D,L-valine (Val), alpha-aminoisobutyric acid (alpha-AIB), D,L-isovaline (Iva), and glycine (Gly). Analysis by high performance liquid chromatography with fluorescence detection (HPLC-FD) showed that only D-Val and non-protein amino acids were abundant after 2250 days. The mixture was re-analyzed in 2012 using HPLC-FD and a triple quadrupole mass spectrometer (QqQ-MS). The analytical results 20 years after the inception of the experiment were strikingly similar to those after 2250 days. To confirm that viable microorganisms were still present, the mixture was re-spiked with Gly in 2012. Aliquots were collected immediately after spiking, and at 5- and 9-month intervals thereafter. Final HPLC-FD/QqQ-MS analyses were performed in 2014. The 2014 analyses revealed that only alpha-AIB, D,L-Iva, and D-Val remained abundant. The disappearance of Gly indicated that microorganisms still lived in the mixture and were capable of consuming protein amino acids. These findings demonstrate that non-protein amino acids are minimally impacted by biological degradation and thus have very long lifetimes under these conditions. Primitive non-protein amino acids from terrestrial synthesis, or meteorite in-fall, likely experienced great-er preservation than protein amino acids in paleo-oceanic environments. Such robust molecules may have reached a steady state concentration dependent on ocean circulation through hydrothermal systems and synthetic input processes. We are presently trying to estimate this concentration.

Parker, Eric T.↗

Clays and Carbonates in a Groundwater-Fed 3.8 Ga Martian Lake: Insights to Subsurface Habitability on Mars

On Earth, the deep biosphere remains a largely unexplored, but clearly important carbon reservoir. Results from some uplifted central peaks in craters on Mars indicate that substantial carbon was also present at depth and might have helped sustain a deep biosphere. In fact, many factors relevant to deep biosphere habitability are more favorable on Mars than on Earth (e.g. porosity of the crust, geothermal gradient). Future exploration of Mars should include landing sites where materials have been exhumed from depth by meteor impact or basins where subsurface fluids have emerged, carrying clues to subsurface habitability. One of the most astrobiologically interesting sites on Mars McLaughlin Crater, a 93 km-diameter impact crater that formed approximately 4 b.y. ago. On the floor of the crater is a stratigraphic section of subhorizontal, layered sedimentary rocks with strong spectroscopic evidence for Fe-rich clay minerals and Mg-rich carbonates, which we interpret as ancient lacustrine deposits. The fluids that formed these materials likely originated in the subsurface, based on the paucity of channels leading into the crater basin and the fact that this is one of the deepest basins on Mars - a good candidate to have experienced upwelling of subsurface fluids. Therefore, the deposits within McLaughlin crater provide insight into subsurface processes on Mars. In this presentation, we will discuss the habitability of the martian subsurface as well as the geology of McLaughlin Crater and the possibility to detect biomarkers at that site with a future landed mission.

Michalski, Joseph↗

The Orbital Design of Alpha Centauri Exoplanet Satellite (ACESat)

Exoplanet candidates discovered by Kepler are too distant for biomarkers to be detected with foreseeable technology. Alpha Centauri has high separation from other stars and is of close proximity to Earth, which makes the binary star system 'low hanging fruit' for scientists. Alpha Centauri Exoplanet Satellite (ACESat) is a mission proposed to Small Explorer Program (SMEX) that will use a coronagraph to search for an orbiting planet around one of the stars of Alpha Centauri. The trajectory design for this mission is presented here where three different trajectories are considered: Low Earth Orbit (LEO), Geosynchronous Orbit (GEO) and a Heliocentric Orbit. Uninterrupted stare time to Alpha Centauri is desirable for meeting science requirements, or an orbit that provides 90% stare time to the science target. The instrument thermal stability also has stringent requirements for proper function, influencing trajectory design.

Alpha Centauri↗

In Situ Radiometric and Exposure Age Dating of the Martian Surface

We determined radiogenic and cosmogenic noble gases in a mudstone on the floor of Gale Crater. A K-Ar age of 4.21 +/- 0.35 billion years represents a mixture of detrital and authigenic components and confirms the expected antiquity of rocks comprising the crater rim. Cosmic-ray-produced 3He, 21Ne, and 36Ar yield concordant surface exposure ages of 78 T 30 million years. Surface exposure occurred mainly in the present geomorphic setting rather than during primary erosion and transport. Our observations are consistent with mudstone deposition shortly after the Gale impact or possibly in a later event of rapid erosion and deposition. The mudstone remained buried until recent exposure by wind-driven scarp retreat. Sedimentary rocks exposed by this mechanism may thus offer the best potential for organic biomarker preservation against destruction by cosmic radiation.

age dating↗

Mineralogy and Astrobiology Detection Using Laser Remote Sensing Instrument

A multispectral instrument based on Raman, laser-induced fluorescence (LIF), laser-induced breakdown spectroscopy (LIBS), and a lidar system provides high-fidelity scientific investigations, scientific input, and science operation constraints in the context of planetary field campaigns with the Jupiter Europa Robotic Lander and Mars Sample Return mission opportunities. This instrument conducts scientific investigations analogous to investigations anticipated for missions to Mars and Jupiter's icy moons. This combined multispectral instrument is capable of performing Raman and fluorescence spectroscopy out to a >100 m target distance from the rover system and provides single-wavelength atmospheric profiling over long ranges (>20 km). In this article, we will reveal integrated remote Raman, LIF, and lidar technologies for use in robotic and lander-based planetary remote sensing applications. Discussions are focused on recently developed Raman, LIF, and lidar systems in addition to emphasizing surface water ice, surface and subsurface minerals, organics, biogenic, biomarker identification, atmospheric aerosols and clouds distributions, i.e., near-field atmospheric thin layers detection for next robotic-lander based instruments to measure all the above-mentioned parameters. OCIS codes: (120.0280) Remote sensing and sensors; (130.0250) Optoelectronics; (280.3640) Lidar; (300.2530) Fluorescence, laser-induced; (300.6450) Spectroscopy, Raman; (300.6365) Spectroscopy, laser induced breakdown

Abedin, M. Nurul↗