371 research outputs found

    First Astronaut- Rover Interaction Field Test

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    The first Astronaut - Rover (ASRO) Interaction field test was conducted successfully on February 22-27, 1999, in Silver Lake, Mojave Desert, California in a representative planetary surface terrain. This test was a joint effort between the NASA Ames Research Center , Moffett Field, California and the NASA Johnson Space Center, Houston, Texas. As prototype advanced planetary surface space suit and rover technologies are being developed for human planetary surface exploration , it has been determined that it is important to better understand the potential interaction and benefits of an EVA astronaut interacting with a robotic rover . This interaction between an EVA astronaut and a robotic rover is seen as complementary and can greatly enhance the productivity and safety of surface excursions . This test also identified design requirements and options in an advanced space suit and robotic rover. The test objectives were: 1. To identify the operational domains where the EVA astronauts and rover are complementary and can interact and thus collaborate in a safe , productive and cost- effective way, 2. To identify preliminary requirements and recommendations for advanced space suits and rovers that facilitate their cooperative and complementary interaction, 3. To develop operational procedures for the astronaut-rover teams in the identified domains, 4. To test these procedures during representative mission scenarios during field tests by simulating the exploration of a planetary surface by an EVA crew interacting with a robotic rover, 5. To train a space suited test subject, simulated Earth-based and l or lander-based science teams, and robotic vehicle operators in mission configurations, and 6. To evaluate and understand socio-technical aspects of the astronaut - rover interaction experiment in order to guide future technologies and designs. Test results and areas for future research in the design of planetary space suits will be discussed

    Planetary Trojans - the main source of short period comets?

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    We present a short review of the impact regime experienced by the terrestrial planets within our own Solar system, describing the three populations of potentially hazardous objects which move on orbits that take them through the inner Solar system. Of these populations, the origins of two (the Near-Earth Asteroids and the Long-Period Comets) are well understood, with members originating in the Asteroid belt and Oort cloud, respectively. By contrast, the source of the third population, the Short-Period Comets, is still under debate. The proximate source of these objects is the Centaurs, a population of dynamically unstable objects that pass perihelion between the orbits of Jupiter and Neptune. However, a variety of different origins have been suggested for the Centaur population. Here, we present evidence that at least a significant fraction of the Centaur population can be sourced from the planetary Trojan clouds, stable reservoirs of objects moving in 1:1 mean-motion resonance with the giant planets (primarily Jupiter and Neptune). Focusing on simulations of the Neptunian Trojan population, we show that an ongoing flux of objects should be leaving that region to move on orbits within the Centaur population. With conservative estimates of the flux from the Neptunian Trojan clouds, we show that their contribution to that population could be of order ~3%, while more realistic estimates suggest that the Neptune Trojans could even be the main source of fresh Centaurs. We suggest that further observational work is needed to constrain the contribution made by the Neptune Trojans to the ongoing flux of material to the inner Solar system, and believe that future studies of the habitability of exoplanetary systems should take care not to neglect the contribution of resonant objects (such as planetary Trojans) to the impact flux that could be experienced by potentially habitable worlds.Comment: 16 pages, 4 figures, published in the International Journal of Astrobiology (the arXiv.org's abstract was shortened, but the original one can be found in the manuscript file

    Violence in southern Sudan.

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    Thresholds of Detection and Identification of Halite Nodule Habitats in the Atacama Desert Using Remote Imaging

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    The guiding theme of Mars exploration is shifting from global and regional habitability assessment to biosignature detection. To locate features likely to contain biosignatures, it is useful to focus on the reliable identification of specific habitats with high biosignature preservation potential. Proposed chloride deposits on Mars may represent evaporitic environments conducive to the preservation of biosignatures. Analogous chloride- bearing, salt-encrusted playas (salars) are a habitat for life in the driest parts of the Atacama Desert, and are also environments with a taphonomic window. The specific geologic features that harbor and preserve microorganisms in Atacama salars are sub- meter to meter scale salt protuberances, or halite nodules. This study focuses on the ability to recognize and map halite nodules using images acquired from an unmanned aerial vehicle (UAV) at spatial resolutions ranging from mm/pixel to that of the highest resolution orbital images available for Mars

    Relation of gallbladder function and Helicobacter pylori infection to gastric mucosa inflammation in patients with symptomatic cholecystolithiasis

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    Background. Inflammatory alterations of the gastric mucosa are commonly caused by Helicobacter pylori (Hp) infection in patients with symptomatic gallstone disease. However, the additional pathogenetic role of an impaired gallbladder function leading to an increased alkaline duodenogastric reflux is controversially discussed. Aim:To investigate the relation of gallbladder function and Hp infection to gastric mucosa inflammation in patients with symptomatic gallstones prior to cholecystectomy. Patients: Seventy-three patients with symptomatic gallstones were studied by endoscopy and Hp testing. Methods: Gastritis classification was performed according to the updated Sydney System and gallbladder function was determined by total lipid concentration of gallbladder bile collected during mainly laparoscopic cholecystectomy. Results: Fifteen patients revealed no, 39 patients mild, and 19 moderate to marked gastritis. No significant differences for bile salts, phospholipids, cholesterol, or total lipids in gallbladder bile were found between these three groups of patients. However, while only 1 out of 54 (< 2%) patients with mild or no gastritis was found histologically positive for Hp, this infection could be detected in 14 (74%) out of 19 patients with moderate to marked gastritis. Conclusion: Moderate to marked gastric mucosa inflammation in gallstone patients is mainly caused by Hp infection, whereas gallbladder function is not related to the degree of gastritis. Thus, an increased alkaline duodenogastric reflux in gallstone patients seems to be of limited pathophysiological relevance. Copyright (c) 2006 S. Karger AG, Basel

    Robotic Technologies for Surveying Habitats and Seeking Evidence of Life: Results from the 2004 Field Experiments of the "Life in the Atacama" Project

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    The Chilean Atacama Desert is the most arid region on Earth and in several ways analogous to Mars. Evidence suggests that the interior of the Atacama is lifeless, yet where the desert meets the Pacific coastal range dessication-tolerant microorganisms are known to exist. The gradient of biodiversity and habitats in the Atacama's subregions remain unexplored and are the focus of the Life in the Atacama project. Our field investigation attempts to bring further scientific understanding of the Atacama as a habitat for life through the creation of robotic astrobiology. This involves capabilities for autonomously traversing hundreds of kilometers while deploying sensors to survey the varying geologic and biologic properties of the environment, Fig. 1. Our goal is to make genuine discoveries about the limits of life on Earth and to generate knowledge about life in extreme environments that can be applied to future planetary missions. Through these experiments we also hope to develop and practice the methods by which a rover might best be employed to survey desert terrain in search of the habitats in which life can survive, or may have in the past

    Abatement of styrene waste gas emission by biofilter and biotrickling filter: comparison of packing materials and inoculation procedures

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    The removal of styrene was studied using 2 biofilters packed with peat and coconut fibre (BF1-P and BF2-C, respectively) and 1 biotrickling filter (BTF) packed with plastic rings. Two inoculation procedures were applied: an enriched culture with strain Pseudomonas putida CECT 324 for biofilters and activated sludge from a municipal wastewater treatment plant for the BTF. Inlet loads (ILs) between 10 and 45 g m-3 h-1 and empty bed residence times (EBRTs) from 30 to 120 s were applied. At inlet concentrations ranging between 200 and 400 mg Nm-3, removal efficiencies between 70 and 95% were obtained in the 3 bioreactors. Maximum elimination capacities (ECs) of 81 and 39 g m-3 h-1 were obtained for the first quarter of the BF1-P and BF2-C, respectively (IL of 173 g m-3 h-1 and EBRT of 60 s in BF1-P; IL of 89 g m-3 h-1 and EBRT of 90 s in BF2-C). A maximum EC of 52 g m-3 h-1 was obtained for the first third of the BTF (IL of 116 g m-3 h-1, EBRT of 45 s). Problems regarding high pressure drop appeared in the peat biofilter, whereas drying episodes occurred in the coconut fibre biofilter. DGGE revealed that the pure culture used for biofilter inoculation was not detected by day 105. Although 2 different inoculation procedures were applied, similar styrene removal at the end of the experiments was observed. The use as inoculum of activated sludge from municipal wastewater treatment plant appears a more feasible option
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