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Sample records for asteroids digging soil

  1. Dig It! The Secrets of Soil

    Science.gov (United States)

    It! The Secrets of Soil Come and Explore! Discover the amazing world of soils with images and information from the Dig It! The Secrets of Soil exhibit from the Smithsonian's National Museum of Natural and new web content will be added over the coming months including a new soil blog. New Interactives

  2. Digging up the Dirt on Soil Safety

    Science.gov (United States)

    Roy, Ken

    2010-01-01

    Should middle school science teachers be concerned about students bringing in unknown sources of soil to work on in class as the activity suggests? The science is well intended, but is it safe? What are some possible safety issues that might be of concern in dealing with soil samples? This month's column provides several examples of unsuspecting…

  3. Structural Bionic Design for Digging Shovel of Cassava Harvester Considering Soil Mechanics

    Directory of Open Access Journals (Sweden)

    Shihao Liu

    2014-01-01

    Full Text Available In order to improve the working performance of cassava harvester, structural bionic design for its digging shovel was conducted. Taking the oriental mole cricket's paws as bionic prototype, a new structural bionic design method for digging shovel was established, which considers the morphology-configuration-function coupling bionic. A comprehensive performance comparison method was proposed, which is used to select the bionic design schemes. The proposed bionic design method was used to improve digging shovel structure of a digging-pulling style cassava harvester, and nine bionic-type digging shovels were obtained with considering the impact of soil mechanics. After conducting mechanical properties comparative analysis for bionic-type digging shovels, the bionic design rules were summed up, and the optimal design scheme of digging shovel was obtained through combining the proposed comprehensive performance comparison method with Analytic Hierarchy Process (AHP. Studies have shown that bionic design method not only can improve the overall mechanical properties of digging shovel, but also can help to improve the harvesting effect of cassava harvester, which provides a new idea for crops harvesting machinery's structural optimization design.

  4. Morphological adaptations for digging and climate-impacted soil properties define pocket gopher (Thomomys spp. distributions.

    Directory of Open Access Journals (Sweden)

    Ariel E Marcy

    Full Text Available Species ranges are mediated by physiology, environmental factors, and competition with other organisms. The allopatric distribution of five species of northern Californian pocket gophers (Thomomys spp. is hypothesized to result from competitive exclusion. The five species in this environmentally heterogeneous region separate into two subgenera, Thomomys or Megascapheus, which have divergent digging styles. While all pocket gophers dig with their claws, the tooth-digging adaptations of subgenus Megascapheus allow access to harder soils and climate-protected depths. In a Northern Californian locality, replacement of subgenus Thomomys with subgenus Megascapheus occurred gradually during the Pleistocene-Holocene transition. Concurrent climate change over this transition suggests that environmental factors--in addition to soil--define pocket gopher distributional limits. Here we show 1 that all pocket gophers occupy the subset of less energetically costly soils and 2 that subgenera sort by percent soil clay, bulk density, and shrink-swell capacity (a mineralogical attribute. While clay and bulk density (without major perturbations stay constant over decades to millennia, low precipitation and high temperatures can cause shrink-swell clays to crack and harden within days. The strong yet underappreciated interaction between soil and moisture on the distribution of vertebrates is rarely considered when projecting species responses to climatic change. Furthermore, increased precipitation alters the weathering processes that create shrink-swell minerals. Two projected outcomes of ongoing climate change--higher temperatures and precipitation--will dramatically impact hardness of soil with shrink-swell minerals. Current climate models do not include factors controlling soil hardness, despite its impact on all organisms that depend on a stable soil structure.

  5. Spatial variability of soil electrical conductivity under the mole rats (Spalax microphthalmus digging activity at the different scales

    Directory of Open Access Journals (Sweden)

    A. V. Zhukov

    2012-07-01

    Full Text Available The soil mounds emerged owing to the mole rats’ digging activity have been shown to be characterised by less electrical conductivity than surrounded soil. This effect is due to the changes of the mounds bulk’s density and moisture. The effect of the mole rats’ digging activity on the soil electrical conductivity has been found not to be restricted by the geometrical border of the mounds. The mounds are surrounded by 1–1.5 m halo of increased soil electrical conductivity. The halo size is increased with the aging of the mound and with the compacting of their aggregation.

  6. Students Dig Deep in the Mystery Soil Lab: A Playful, Inquiry-Based Soil Laboratory Project

    Science.gov (United States)

    Thiet, Rachel K.

    2014-01-01

    The Mystery Soil Lab, a playful, inquiry-based laboratory project, is designed to develop students' skills of inquiry, soil analysis, and synthesis of foundational concepts in soil science and soil ecology. Student groups are given the charge to explore and identify a "Mystery Soil" collected from a unique landscape within a 10-mile…

  7. Asteroids

    International Nuclear Information System (INIS)

    Bell, J.F.; Gaffey, M.J.

    1989-01-01

    During the past 15 yr much progress has been made in the study of the asteroids with optical, infrared, and radar telescopes. Simultaneously a vast body of petrologic, chemical and isotopic data has been acquired for meteorites, which are actual samples of asteroids. This work has demonstrated that asteroids vary widely in composition and thermal history in a systematic but complex way with orbital position and size. The authors report that it appears that these variations can be explained to first order by a simple model invoking three principal mechanisms: condensation of various known and unknown classes of chondritic material at radial locations in the nebula controlled by the temperature and composition; intense metamorphic heating after accretion which declined rapidly with both increasing solar distance and smaller planetesimal size, producing complete differentiation in some inner belt objects, incomplete differentiation in many more, and extensive metamorphism and aqueous alteration in middle-belt objects; and complex collisional fragmentation often controlled by internal strength gradients due to irregular distribution of metal

  8. Soil moisture and excavation behaviour in the Chaco leaf-cutting ant (Atta vollenweideri: digging performance and prevention of water inflow into the nest.

    Directory of Open Access Journals (Sweden)

    Steffen Pielström

    Full Text Available The Chaco leaf-cutting ant Atta vollenweideri is native to the clay-heavy soils of the Gran Chaco region in South America. Because of seasonal floods, colonies are regularly exposed to varying moisture across the soil profile, a factor that not only strongly influences workers' digging performance during nest building, but also determines the suitability of the soil for the rearing of the colony's symbiotic fungus. In this study, we investigated the effects of varying soil moisture on behaviours associated with underground nest building in A. vollenweideri. This was done in a series of laboratory experiments using standardised, plastic clay-water mixtures with gravimetric water contents ranging from relatively brittle material to mixtures close to the liquid limit. Our experiments showed that preference and group-level digging rate increased with increasing water content, but then dropped considerably for extremely moist materials. The production of vibrational recruitment signals during digging showed, on the contrary, a slightly negative linear correlation with soil moisture. Workers formed and carried clay pellets at higher rates in moist clay, even at the highest water content tested. Hence, their weak preference and low group-level excavation rate observed for that mixture cannot be explained by any inability to work with the material. More likely, extremely high moistures may indicate locations unsuitable for nest building. To test this hypothesis, we simulated a situation in which workers excavated an upward tunnel below accumulated surface water. The ants stopped digging about 12 mm below the interface soil/water, a behaviour representing a possible adaptation to the threat of water inflow field colonies are exposed to while digging under seasonally flooded soils. Possible roles of soil water in the temporal and spatial pattern of nest growth are discussed.

  9. Soil Moisture and Excavation Behaviour in the Chaco Leaf-Cutting Ant (Atta vollenweideri): Digging Performance and Prevention of Water Inflow into the Nest

    Science.gov (United States)

    Pielström, Steffen; Roces, Flavio

    2014-01-01

    The Chaco leaf-cutting ant Atta vollenweideri is native to the clay-heavy soils of the Gran Chaco region in South America. Because of seasonal floods, colonies are regularly exposed to varying moisture across the soil profile, a factor that not only strongly influences workers' digging performance during nest building, but also determines the suitability of the soil for the rearing of the colony's symbiotic fungus. In this study, we investigated the effects of varying soil moisture on behaviours associated with underground nest building in A. vollenweideri. This was done in a series of laboratory experiments using standardised, plastic clay-water mixtures with gravimetric water contents ranging from relatively brittle material to mixtures close to the liquid limit. Our experiments showed that preference and group-level digging rate increased with increasing water content, but then dropped considerably for extremely moist materials. The production of vibrational recruitment signals during digging showed, on the contrary, a slightly negative linear correlation with soil moisture. Workers formed and carried clay pellets at higher rates in moist clay, even at the highest water content tested. Hence, their weak preference and low group-level excavation rate observed for that mixture cannot be explained by any inability to work with the material. More likely, extremely high moistures may indicate locations unsuitable for nest building. To test this hypothesis, we simulated a situation in which workers excavated an upward tunnel below accumulated surface water. The ants stopped digging about 12 mm below the interface soil/water, a behaviour representing a possible adaptation to the threat of water inflow field colonies are exposed to while digging under seasonally flooded soils. Possible roles of soil water in the temporal and spatial pattern of nest growth are discussed. PMID:24748382

  10. Digging deeper - How soil biota drive and respond to plant invasions

    NARCIS (Netherlands)

    Shelby, Natasha; Duncan, Richard P.; Putten, Van Der Wim H.; Mcginn, Kevin J.; Weser, Carolin; Hulme, Philip E.

    2016-01-01

    1. The performance of introduced plants can be limited by the availability of soil mutualists outside their native range, but how interactions with mutualists differ between ranges is largely unknown. If mutualists are absent, incompatible or parasitic, plants may compensate by investing more in

  11. Digging the New York City Skyline: soil fungal communities in green roofs and city parks.

    Directory of Open Access Journals (Sweden)

    Krista L McGuire

    Full Text Available In urban environments, green roofs provide a number of benefits, including decreased urban heat island effects and reduced energy costs for buildings. However, little research has been done on the non-plant biota associated with green roofs, which likely affect their functionality. For the current study, we evaluated whether or not green roofs planted with two native plant communities in New York City functioned as habitats for soil fungal communities, and compared fungal communities in green roof growing media to soil microbial composition in five city parks, including Central Park and the High Line. Ten replicate roofs were sampled one year after planting; three of these roofs were more intensively sampled and compared to nearby city parks. Using Illumina sequencing of the fungal ITS region we found that green roofs supported a diverse fungal community, with numerous taxa belonging to fungal groups capable of surviving in disturbed and polluted habitats. Across roofs, there was significant biogeographical clustering of fungal communities, indicating that community assembly of roof microbes across the greater New York City area is locally variable. Green roof fungal communities were compositionally distinct from city parks and only 54% of the green roof taxa were also found in the park soils. Phospholipid fatty acid analysis revealed that park soils had greater microbial biomass and higher bacterial to fungal ratios than green roof substrates. City park soils were also more enriched with heavy metals, had lower pH, and lower quantities of total bases (Ca, K, and Mg compared to green roof substrates. While fungal communities were compositionally distinct across green roofs, they did not differentiate by plant community. Together, these results suggest that fungi living in the growing medium of green roofs may be an underestimated component of these biotic systems functioning to support some of the valued ecological services of green roofs.

  12. Digging the New York City Skyline: soil fungal communities in green roofs and city parks.

    Science.gov (United States)

    McGuire, Krista L; Payne, Sara G; Palmer, Matthew I; Gillikin, Caitlyn M; Keefe, Dominique; Kim, Su Jin; Gedallovich, Seren M; Discenza, Julia; Rangamannar, Ramya; Koshner, Jennifer A; Massmann, Audrey L; Orazi, Giulia; Essene, Adam; Leff, Jonathan W; Fierer, Noah

    2013-01-01

    In urban environments, green roofs provide a number of benefits, including decreased urban heat island effects and reduced energy costs for buildings. However, little research has been done on the non-plant biota associated with green roofs, which likely affect their functionality. For the current study, we evaluated whether or not green roofs planted with two native plant communities in New York City functioned as habitats for soil fungal communities, and compared fungal communities in green roof growing media to soil microbial composition in five city parks, including Central Park and the High Line. Ten replicate roofs were sampled one year after planting; three of these roofs were more intensively sampled and compared to nearby city parks. Using Illumina sequencing of the fungal ITS region we found that green roofs supported a diverse fungal community, with numerous taxa belonging to fungal groups capable of surviving in disturbed and polluted habitats. Across roofs, there was significant biogeographical clustering of fungal communities, indicating that community assembly of roof microbes across the greater New York City area is locally variable. Green roof fungal communities were compositionally distinct from city parks and only 54% of the green roof taxa were also found in the park soils. Phospholipid fatty acid analysis revealed that park soils had greater microbial biomass and higher bacterial to fungal ratios than green roof substrates. City park soils were also more enriched with heavy metals, had lower pH, and lower quantities of total bases (Ca, K, and Mg) compared to green roof substrates. While fungal communities were compositionally distinct across green roofs, they did not differentiate by plant community. Together, these results suggest that fungi living in the growing medium of green roofs may be an underestimated component of these biotic systems functioning to support some of the valued ecological services of green roofs.

  13. Digging a Little Deeper: Microbial Communities, Molecular Composition and Soil Organic Matter Turnover along Tropical Forest Soil Depth Profiles

    Science.gov (United States)

    Pett-Ridge, J.; McFarlane, K. J.; Heckman, K. A.; Reed, S.; Green, E. A.; Nico, P. S.; Tfaily, M. M.; Wood, T. E.; Plante, A. F.

    2016-12-01

    Tropical forest soils store more carbon (C) than any other terrestrial ecosystem and exchange vast amounts of CO2, water, and energy with the atmosphere. Much of this C is leached and stored in deep soil layers where we know little about its fate or the microbial communities that drive deep soil biogeochemistry. Organic matter (OM) in tropical soils appears to be associated with mineral particles, suggesting deep soils may provide greater C stabilization. However, few studies have evaluated sub-surface soils in tropical ecosystems, including estimates of the turnover times of deep soil C, the sensitivity of this C to global environmental change, and the microorganisms involved. We quantified bulk C pools, microbial communities, molecular composition of soil organic matter, and soil radiocarbon turnover times from surface soils to 1.5m depths in multiple soil pits across the Luquillo Experimental Forest, Puerto Rico. Soil C, nitrogen, and root and microbial biomass all declined exponentially with depth; total C concentrations dropped from 5.5% at the surface to communities in surface soils (Acidobacteria and Proteobacteria) versus those below the active rooting zone (Verrucomicrobia and Thaumarchaea). High resolution mass spectrometry (FTICR-MS) analyses suggest a shift in the composition of OM with depth (especially in the water soluble fraction), an increase in oxidation, and decreasing H/C with depth (indicating higher aromaticity). Additionally, surface samples were rich in lignin-like compounds of plant origin that were absent with depth. Soil OM 14C and mean turnover times were variable across replicate horizons, ranging from 3-1500 years at the surface, to 5000-40,000 years at depth. In comparison to temperate deciduous forests, these 14C values reflect far older soil C. Particulate organic matter (free light fraction), with a relatively modern 14C was found in low but measureable concentration in even the deepest soil horizons. Our results indicate these

  14. Test dig selv!

    DEFF Research Database (Denmark)

    Hølge-Hazelton, Bibi; Nielsen, Gregers; Langstrup, Henriette

    2011-01-01

    Teknologirådet omkring rapporten ”Test dig selv! – Vurderinger og anbefalinger vedrørende anvendelse medicinsk udstyr til selvtestning. Offentliggjort d. 25.10.11.......Teknologirådet omkring rapporten ”Test dig selv! – Vurderinger og anbefalinger vedrørende anvendelse medicinsk udstyr til selvtestning. Offentliggjort d. 25.10.11....

  15. Digging of 'Snow White' Begins

    Science.gov (United States)

    2008-01-01

    NASA's Phoenix Mars Lander began excavating a new trench, dubbed 'Snow White,' in a patch of Martian soil located near the center of a polygonal surface feature, nicknamed 'Cheshire Cat.' The trench is about 2 centimeters (.8 inches) deep and 30 centimeters (about 12 inches) long. The 'dump pile' is located at the top of the trench, the side farthest away from the lander, and has been dubbed 'Croquet Ground.' The digging site has been named 'Wonderland.' At this early stage of digging, the Phoenix team did not expect to find any of the white material seen in the first trench, now called 'Dodo-Goldilocks.' That trench showed white material at a depth of about 5 centimeters (2 inches). More digging of Snow White is planned for coming sols, or Martian days. The dark portion of this image is the shadow of the lander's solar panel; the bright areas within this region are not in shadow. Snow White was dug on Sol 22 (June 17, 2008) with Phoenix's Robotic Arm. This picture was acquired on the same day by the lander's Surface Stereo Imager. This image has been enhanced to brighten shaded areas. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  16. Digging Movie from Phoenix's Sol 18

    Science.gov (United States)

    2008-01-01

    The Surface Stereo Imager on NASA's Phoenix Mars Lander recorded the images combined into this movie of the lander's Robotic Arm enlarging and combining the two trenches informally named 'Dodo' (left) and 'Goldilocks.' The 21 images in this sequence were taken over a period of about 2 hours during Phoenix's Sol 18 (June 13, 2008), or the 18th Martian day since landing. The main purpose of the Sol 18 dig was to dig deeper for learning the depth of a hard underlying layer. A bright layer, possibly ice, was increasingly exposed as the digging progressed. Further digging and scraping in the combined Dodo-Goldilocks trench was planned for subsequent sols. The combined trench is about 20 centimeters (about 8 inches) wide. The depth at the end of the Sol 18 digging is 5 to 6 centimeters (about 2 inches). The Goldilocks trench was the source of soil samples 'Baby Bear' and 'Mama Bear,' which were collected on earlier sols and delivered to instruments on the lander deck. The Dodo trench was originally dug for practice in collecting and depositing soil samples. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  17. Kidnapping small icy asteroids in Earth near encounter to harbour life and to deflect trajectory

    Science.gov (United States)

    Fargion, Daniele

    2016-07-01

    The inter-planetary flight for human being is under danger because of unscreened and lethal solar flare radioactive showers. The screening of the astronauts by huge superconducting magnetic fields is unrealistic by many reasons. On the contrary the ability to reach nearby icy asteroids, to harbour there a complete undergound room where ecological life systems are first set, this goal may offer a later natural and safe currier for future human stations and enterprise. The need to deflect such a small size (a few thousands tons objects) maybe achieved by micro nuclear engines able to dig the asteroid icy skin, to heat and propel the soil by a synchronous jet engine array, bending and driving it to any desired trajectories. The need for such a wide collection of icy asteroid stations, often in a robotic ibernated state, it will offer the safe help station, raft in the wide space sea, where to collect material or energy in long human planetary travels.

  18. Optimized Bucket Wheel Design for Asteroid Excavation

    OpenAIRE

    Nallapu, Ravi Teja; Thoesen, Andrew; Garvie, Laurence; Asphaug, Erik; Thangavelautham, Jekanthan

    2017-01-01

    Current spacecraft need to launch with all of their required fuel for travel. This limits the system performance, payload capacity, and mission flexibility. One compelling alternative is to perform In-Situ Resource Utilization (ISRU) by extracting fuel from small bodies in local space such as asteroids or small satellites. Compared to the Moon or Mars, the microgravity on an asteroid demands a fraction of the energy for digging and accessing hydrated regolith just below the surface. Previous ...

  19. DigDag

    DEFF Research Database (Denmark)

    Knudsen, Bo Nissen

    , e.g. boundary changes, name changes as well as changes in administrative structures. Seen over centuries, public and ecclesiastical administration becomes increasingly complex, resulting in ever increasing needs for updates in administrative divisions. A substantial number of digitised archival...... registers in Denmark use, among others, geographical/administrative entrances. The entrance is usually a topographical code (e.g. settlement, parish) or local authority jurisdiction (e.g. customs service, police districts). Due to changes in the administrative divisions, most of the geocodes are unique...... to each archive, or archival system. The DigDag project establishes a uniform research infrastructure through a webGIS within history, archaeology, place-names, statistics and geography: a digital cartographical skeleton for thematic mapping and analysis which will generate new interdisciplinary research...

  20. Asteroid team

    International Nuclear Information System (INIS)

    Matson, D.L.

    1988-01-01

    The purpose of this task is to support asteroid research and the operation of an Asteroid Team within the Earth and Space Sciences Division at the Jet Propulsion Laboratory (JPL). The Asteroid Team carries out original research on asteroids in order to discover, better characterize and define asteroid properties. This information is needed for the planning and design of NASA asteroid flyby and rendezvous missions. The asteroid Team also provides scientific and technical advice to NASA and JPL on asteroid related programs. Work on asteroid classification continued and the discovery of two Earth-approaching M asteroids was published. In the asteroid photometry program researchers obtained N or Q photometry for more than 50 asteroids, including the two M-earth-crossers. Compositional analysis of infrared spectra (0.8 to 2.6 micrometer) of asteroids is continuing. Over the next year the work on asteroid classification and composition will continue with the analysis of the 60 reduced infrared spectra which we now have at hand. The radiometry program will continue with the reduction of the N and Q bandpass data for the 57 asteroids in order to obtain albedos and diameters. This year the emphasis will shift to IRAS follow-up observations; which includes objects not observed by IRAS and objects with poor or peculiar IRAS data. As in previous year, we plan to give top priority to any opportunities for observing near-Earth asteroids and the support (through radiometric lightcurve observations from the IRTF) of any stellar occultations by asteroids for which occultation observation expeditions are fielded. Support of preparing of IRAS data for publication and of D. Matson for his participation in the NASA Planetary Astronomy Management and Operations Working Group will continue

  1. Asteroid team

    Science.gov (United States)

    Matson, D. L.

    1988-01-01

    The purpose of this task is to support asteroid research and the operation of an Asteroid Team within the Earth and Space Sciences Division at the Jet Propulsion Laboratory (JPL). The Asteroid Team carries out original research on asteroids in order to discover, better characterize and define asteroid properties. This information is needed for the planning and design of NASA asteroid flyby and rendezvous missions. The asteroid Team also provides scientific and technical advice to NASA and JPL on asteroid related programs. Work on asteroid classification continued and the discovery of two Earth-approaching M asteroids was published. In the asteroid photometry program researchers obtained N or Q photometry for more than 50 asteroids, including the two M-earth-crossers. Compositional analysis of infrared spectra (0.8 to 2.6 micrometer) of asteroids is continuing. Over the next year the work on asteroid classification and composition will continue with the analysis of the 60 reduced infrared spectra which we now have at hand. The radiometry program will continue with the reduction of the N and Q bandpass data for the 57 asteroids in order to obtain albedos and diameters. This year the emphasis will shift to IRAS follow-up observations; which includes objects not observed by IRAS and objects with poor or peculiar IRAS data. As in previous year, we plan to give top priority to any opportunities for observing near-Earth asteroids and the support (through radiometric lightcurve observations from the IRTF) of any stellar occultations by asteroids for which occultation observation expeditions are fielded. Support of preparing of IRAS data for publication and of D. Matson for his participation in the NASA Planetary Astronomy Management and Operations Working Group will continue.

  2. Careful where you dig

    International Nuclear Information System (INIS)

    Kelly, D.S.

    1996-01-01

    Improved excavation techniques help contractors at former nuclear weapons site avoid digging up the past. The Department of Energy's Hanford Site is an excavator's nightmare. It's one of the country's oldest nuclear sites, with facilities that were built in the rush to win a world war and then a decades-long arms race. During World War II the reactors and process facilities at Hanford were constructed with utmost secrecy. For instance, the site was divided up into various, distinct processing areas -- each with its own separate survey coordinate system to confuse an invading enemy. In 1989 when the Cold War ended, Hanford began its metamorphosis from top secret defense site to the nation's largest and most complex nuclear waste cleanup project. National defense urgency and past environmental and as-built standards of the time left a legacy of chemical discharges and semi-hidden utilities. Also, the new cleanup mission included a new interest in privatization and outsourcing for engineering and services. This brought an influx of new contractors and personnel with no work experience of the Hanford Site. In the 50-year history of Hanford, various government agencies, contractors and their policies have come and gone. As federal budgets rose and fell, so did the accuracy of as-built documentation. At one point, jobs below$150,000 in value were not even documented as they were built because it wasn't considered cost-effective. Many utilities were field-routed, leaving no dependable as-built drawings. To be cost-effective, adjacent construction projects often shared a common excavation, both adding underground lines to the same trench. This 1ed to mixed confidence levels in the accuracy of the as-builts

  3. Dig-face monitoring during excavation of a radioactive plume at Mound Laboratory, Ohio

    International Nuclear Information System (INIS)

    Josten, N.E.; Gehrke, R.J.; Carpenter, M.V.

    1995-12-01

    A dig-face monitoring system consists of onsite hardware for collecting information on changing chemical, radiological, and physical conditions in the subsurface soil during the hazardous site excavation. A prototype dig-face system was take to Mount Laboratory for a first trial. Mound Area 7 was the site of historical disposals of 232 Th, 227 Ac, and assorted debris. The system was used to monitor a deep excavation aimed at removing 227 Ac-contaminated soils. Radiological, geophysical, and topographic sensors were used to scan across the excavation dig-face at four successive depths as soil was removed. A 3-D image of the contamination plumes was developed; the radiation sensor data indicated that only a small portion of the excavated soil volume was contaminated. The spatial information produced by the dig-face system was used to direct the excavation activities into the area containing the 227 Ac and to evaluate options for handling the separate 232 Th plume

  4. Extraction of Volatiles from Regolith or Soil on Mars, the Moon, and Asteroids

    Science.gov (United States)

    Linne, Diane; Kleinhenz, Julie; Trunek, Andrew; Hoffman, Stephen; Collins, Jacob

    2017-01-01

    NASA's Advanced Exploration Systems ISRU Technology Project is evaluating concepts to extract water from all resource types Near-term objectives: Produce high-fidelity mass, power, and volume estimates for mining and processing systems Identify critical challenges for development focus Begin demonstration of component and subsystem technologies in relevant environment Several processor types: Closed processors either partially or completely sealed during processing Open air processors operates at Mars ambient conditions In-situ processors Extract product directly without excavation of raw resource Design features Elimination of sweep gas reduces dust particles in water condensate Pressure maintained by height of soil in hopper Model developed to evaluate key design parameters Geometry: conveyor diameter, screw diameter, shaft diameter, flight spacing and pitch Operational: screw speed vs. screw length (residence time) Thermal: Heat flux, heat transfer to soil Testing to demonstrate feasibility and performance Agglomeration, clogging Pressure rise forced flow to condenser.

  5. Asteroid taxonomy

    International Nuclear Information System (INIS)

    Tholen, D.J.

    1989-01-01

    The spectral reflectivity of asteroid surfaces over the wavelength range of 0.3 to 1.1 μm can be used to classify these objects onto several broad groups with similar spectral characteristics. The three most recently developed taxonomies group the asteroids into 9, 11 or 14 different classes, depending on the technique used to perform the analysis. The distribution of the taxonomic classes shows that darker and redder objects become more dominant at larger heliocentric distances, while the rare asteroid types are found more frequently among the small objects of the planet-crossing population

  6. Digging Deep: how the convergence of national-scale and field-based soil core data shines a light on sustainability of wetland carbon sequestration

    Science.gov (United States)

    Windham-Myers, L.; Holmquist, J. R.; Sundquist, E. T.; Drexler, J. Z.; Bliss, N.

    2016-12-01

    Wetland soils have long been recognized as conditional archives of past environments, including vegetation structure, nutrient status, sediment supply and the variability in those factors. Both sedimentary processes and organic accretion processes form the soil matrix that identifies wetland soils as "hydric" while also providing archival insights. As repositories of information on net biogeochemical processes, their down-core and across-site structure can show both consistency and distinction. Through several related studies, we have been exploring the use of component-level U.S. Natural Resources Conservation Service (NRCS) Soil Survey data (SSURGO) to map carbon density to 1m depth across wetlands of the US, with an emphasis on coastal wetlands. To assess the accuracy of mapped carbon data from SSURGO, several field-generated datasets (public or compiled for the NASA-funded Blue Carbon Monitoring Project) have been extracted for key metrics such as dry bulk density (g/cc), organic carbon content (%C by combustion) and the combination, soil carbon density (g C /cc) with depth. These profiles indicate ecogeomorphic feedbacks of elevation, vegetation structure and biogeochemical processes through millennia, illustrating both resilience and shifts in behavior that constrain wetland extent as well as wetland function. National datasets such as SSURGO and validation datasets such as the EPA's National Wetland Condition Assessment (NWCA) and Louisiana's Coastwide Reference Monitoring System (CRMS) are publically available and have been underutilized for predicting and/or validating changes in wetland carbon dynamics. We have explored their use for interpretating and understanding changing carbon accretion rates, changing wetland extents through elevation gain or loss, and changing methane emissions. This talk will focus on insights for wetland carbon sequestration functions as determined by soil core structure, both for coastal settings and potentially for inland

  7. Asteroids IV

    Science.gov (United States)

    Michel, Patrick; DeMeo, Francesca E.; Bottke, William F.

    Asteroids are fascinating worlds. Considered the building blocks of our planets, many of the authors of this book have devoted their scientific careers to exploring them with the tools of our trade: ground- and spacebased observations, in situ space missions, and studies that run the gamut from theoretical modeling efforts to laboratory work. Like fossils for paleontologists, or DNA for geneticists, they allow us to construct a veritable time machine and provide us with tantalizing glimpses of the earliest nature of our solar system. By investigating them, we can probe what our home system was like before life or even the planets existed. The origin and evolution of life on our planet is also intertwined with asteroids in a different way. It is believed that impacts on the primordial Earth may have delivered the basic components for life, with biology favoring attributes that could more easily survive the aftermath of such energetic events. In this fashion, asteroids may have banished many probable avenues for life to relative obscurity. Similarly, they may have also prevented our biosphere from becoming more complex until more recent eras. The full tale of asteroid impacts on the history of our world, and how human life managed to emerge from myriad possibilities, has yet to be fully told. The hazard posed by asteroid impacts to our civilization is low but singular. The design of efficient mitigation strategies strongly relies on asteroid detection by our ground- and spacebased surveys as well as knowledge of their physical properties. A more positive motivation for asteroid discovery is that the proximity of some asteroids to Earth may allow future astronauts to harvest their water and rare mineral resources for use in exploration. A key goal of asteroid science is therefore to learn how humans and robotic probes can interact with asteroids (and extract their materials) in an efficient way. We expect that these adventures may be commonplace in the future

  8. Digging up your dirt. High school students combine small-scale respiration and soil carbon measurements with satellite imagery in hands-on inquiry activities.

    Science.gov (United States)

    Kemper, K.; Throop, H.

    2015-12-01

    One of the greatest impacts on the global carbon cycle is changes in land use. Making this concept relevant and inquiry-based for high school students is challenging. Many are familiar with reconstructing paleo-climate from ice core data, but few have a connection to current climate research. Many students ask questions like 'What will our area be like in 20 years?' or 'How much does planting trees help?' while few have the scientific language to engage in a discussion to answer these questions. Our work connects students to climate change research in several ways: first, teacher Keska Kemper engaged in field research with Dr. Heather Throop creating a 'teacher in the field' perspective for students in the classroom. Dr. Throop met with Keska Kemper's students several times to develop an inquiry-based field study. Students predicted and then measured rates of respiration between different soil types in an urban park close to their school. Students then could compare their results from Portland, Oregon to Throop's work across a rain gradient in Australia. Discussions about percent tree cover and soil carbon helped students see connections between land use changes and changes in carbon cycling. Last, students examined satellite imagery to determine percent tree cover and numberss of trees to compare to soil carbon in the same region. Students were able to examine imagery over the last 30 years to visualize land use changes in the greater Portland area.

  9. Digging Deeper: Development and evaluation of an untargeted metabolomics approach to identify biogeochemical hotspots with depth and by vegetation type in Arctic tundra soils

    Science.gov (United States)

    Ladd, M.; Wullschleger, S.; Hettich, R.

    2017-12-01

    Elucidating the chemical composition of low molecular weight (LMW) dissolved organic matter (DOM), and monitoring how this bioavailable pool varies over space and time, is critical to understanding the controlling mechanisms that underlie carbon release and storage in Arctic systems. Due to analytical challenges however, relatively little is known about how this complex mixture of small molecules varies with soil depth or how it may be influenced by vegetation. In this study, we evaluated an untargeted metabolomics approach for the characterization of LMW DOM in water extracts, and applied this approach in soil cores (10-cm diam., 30-cm depth), obtained near Barrow, Alaska (71° 16' N) from the organic-rich active layer where the aboveground vegetation was primarily either Carex aquatilis or Eriophorum angustifolium, two species commonly found in tundra systems. We hypothesized that by using a discovery-based approach, spatial patterns of chemical diversity could be identified, enabling the detection of biogeochemical hotspots across scales. LMW DOM profiles from triplicate water extracts were characterized using dual-separation, nano-liquid chromatography (LC) coupled to an electrospray Orbitrap mass spectrometer in positive and negative ion modes. Both LC separations—reversed-phase and hydrophilic interaction chromatography—were achieved with gradient elutions in 15 minutes. Using a precursor and fragment mass measurement accuracy of nutrients) impact carbon fluxes in the Arctic at the landscape-scale.

  10. Asteroid Satellites

    Science.gov (United States)

    Merline, W. J.

    2001-11-01

    Discovery and study of small satellites of asteroids or double asteroids can yield valuable information about the intrinsic properties of asteroids themselves and about their history and evolution. Determination of the orbits of these moons can provide precise masses of the primaries, and hence reliable estimates of the fundamental property of bulk density. This reveals much about the composition and structure of the primary and will allow us to make comparisons between, for example, asteroid taxonomic type and our inventory of meteorites. The nature and prevalence of these systems will also give clues as to the collisional environment in which they formed, and have further implications for the role of collisions in shaping our solar system. A decade ago, binary asteroids were more of a theoretical curiosity. In 1993, the Galileo spacecraft allowed the first undeniable detection of an asteroid moon, with the discovery of Dactyl, a small moon of Ida. Since that time, and particularly in the last year, the number of known binaries has risen dramatically. Previously odd-shaped and lobate near-Earth asteroids, observed by radar, have given way to signatures indicating, almost certainly, that at least four NEAs are binary systems. The tell-tale lightcurves of several other NEAs reveal a high likelihood of being double. Indications are that among the NEAs, there may be a binary frequency of several tens of percent. Among the main-belt asteroids, we now know of 6 confirmed binary systems, although their overall frequency is likely to be low, perhaps a few percent. The detections have largely come about because of significant advances in adaptive optics systems on large telescopes, which can now reduce the blurring of the Earth's atmosphere to compete with the spatial resolution of space-based imaging (which itself, via HST, is now contributing valuable observations). Most of these binary systems have similarities, but there are important exceptions. Searches among other

  11. Digging up food: excavation stone tool use by wild capuchin monkeys.

    Science.gov (United States)

    Falótico, Tiago; Siqueira, José O; Ottoni, Eduardo B

    2017-07-24

    Capuchin monkeys at Serra da Capivara National Park (SCNP) usually forage on the ground for roots and fossorial arthropods, digging primarily with their hands but also using stone tools to loosen the soil and aid the digging process. Here we describe the stone tools used for digging by two groups of capuchins on SCNP. Both groups used tools while digging three main food resources: Thiloa glaucocarpa tubers, Ocotea sp roots, and trapdoor spiders. One explanation for the occurrence of tool use in primates is the "necessity hypothesis", which states that the main function of tool use is to obtain fallback food. We tested for this, but only found a positive correlation between plant food availability and the frequency of stone tools' use. Thus, our data do not support the fallback food hypothesis for the use of tools to access burrowed resources.

  12. Tumbling asteroids

    Czech Academy of Sciences Publication Activity Database

    Pravec, Petr; Harris, A. W.; Scheirich, Peter; Kušnirák, Peter; Kotková, Lenka; Hergenrother, C.; Mottola, S.; Hicks, M. D.; Masi, G.; Krugly, Yu. N.; Shevchenko, V. G.; Nolan, M. C.; Howell, E. S.; Kaasalainen, M.; Galád, Adrián; Brown, P.; DeGraff, D. R.; Lambert, J.V.; Cooney, W.R.; Foglia, S.

    2005-01-01

    Roč. 1, č. 173 (2005), s. 108-131 ISSN 0019-1035 R&D Projects: GA AV ČR IAA3003204 Keywords : near-Earth objects * fast-rotating asteroids Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.244, year: 2005

  13. Asteroids II

    International Nuclear Information System (INIS)

    Binzel, R.P.; Gehrels, T.; Matthews, M.S.

    1989-01-01

    This book presents an introduction to asteroids. A description of exploration techniques, details on their physical properties, discussions of their origin and evolution, an examination of their interrelations with meteorites and comets followed by an attempt at a big picture framework are given

  14. Radionuclide daughter inventory generator code: DIG

    International Nuclear Information System (INIS)

    Fields, D.E.; Sharp, R.D.

    1985-09-01

    The Daughter Inventory Generator (DIG) code accepts a tabulation of radionuclide initially present in a waste stream, specified as amounts present either by mass or by activity, and produces a tabulation of radionuclides present after a user-specified elapsed time. This resultant radionuclide inventory characterizes wastes that have undergone daughter ingrowth during subsequent processes, such as leaching and transport, and includes daughter radionuclides that should be considered in these subsequent processes or for inclusion in a pollutant source term. Output of the DIG code also summarizes radionuclide decay constants. The DIG code was developed specifically to assist the user of the PRESTO-II methodology and code in preparing data sets and accounting for possible daughter ingrowth in wastes buried in shallow-land disposal areas. The DIG code is also useful in preparing data sets for the PRESTO-EPA code. Daughter ingrowth in buried radionuclides and in radionuclides that have been leached from the wastes and are undergoing hydrologic transport are considered, and the quantities of daughter radionuclide are calculated. Radionuclide decay constants generated by DIG and included in the DIG output are required in the PRESTO-II code input data set. The DIG accesses some subroutines written for use with the CRRIS system and accesses files containing radionuclide data compiled by D.C. Kocher. 11 refs

  15. Geotechnical Tests on Asteroid Simulant Orgueil

    Science.gov (United States)

    Garcia, Alexander D'marco

    2017-01-01

    In the last 100 years, the global population has more than quadrupled to over seven billion people. At the same time, the demand for food and standard of living has been increasing which has amplified the global water use by nearly eight times from approximately 500 to 4000 cu km per yr from 1900 to 2010. With the increasing concern to sustain the growing population on Earth it is necessary to seek other approaches to ensure that our planet will have resources for generations to come. In recent years, the advancement of space travel and technology has allowed the idea of mining asteroids with resources closer to becoming a reality. During the duration of the internship at NASA Kennedy Space Center, several geotechnical tests were conducted on BP-1 lunar simulant and asteroid simulant Orgueil. The tests that were conducted on BP-1 was to practice utilizing the equipment that will be used on the asteroid simulant and the data from those tests will be omitted from report. Understanding the soil mechanics of asteroid simulant Orgueil will help provide basis for future technological advances and prepare scientists for the conditions they may encounter when mining asteroids becomes reality in the distant future. Distinct tests were conducted to determine grain size distribution, unconsolidated density, and maximum density. Once the basic properties are known, the asteroid simulant will be altered to different levels of compaction using a vibrator table to see how compaction affects the density. After different intervals of vibration compaction, a miniature vane shear test will be conducted. Laboratory vane shear testing is a reliable tool to investigate strength anisotropy in the vertical and horizontal directions of a very soft to stiff saturated fine-grained clayey soil. This test will provide us with a rapid determination of the shear strength on the undisturbed compacted regolith. The results of these tests will shed light on how much torque is necessary to drill

  16. First Dodo Trench with White Layer Visible in Dig Area

    Science.gov (United States)

    2008-01-01

    These color images were taken by NASA's Phoenix Mars Lander's Stereo Surface Imager on the ninth Martian day of the mission, or Sol 9 (June 3, 2008). The images of the trench shows a white layer that has been uncovered by the Robotic Arm (RA) scoop and is now visible in the wall of the trench. This trench was the first one dug by the RA to understand the Martian soil and plan the digging strategy. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  17. Classification of IRAS asteroids

    International Nuclear Information System (INIS)

    Tedesco, E.F.; Matson, D.L.; Veeder, G.J.

    1989-01-01

    Albedos and spectral reflectances are essential for classifying asteroids. For example, classes E, M and P are indistinguishable without albedo data. Colorometric data are available for about 1000 asteroids but, prior to IRAS, albedo data was available for only about 200. IRAS broke this bottleneck by providing albedo data on nearly 2000 asteroids. Hence, excepting absolute magnitudes, the albedo and size are now the most common asteroid physical parameters known. In this chapter the authors present the results of analyses of IRAS-derived asteroid albedos, discuss their application to asteroid classification, and mention several studies which might be done to exploit further this data set

  18. Asteroid/meteorite streams

    Science.gov (United States)

    Drummond, J.

    The independent discovery of the same three streams (named alpha, beta, and gamma) among 139 Earth approaching asteroids and among 89 meteorite producing fireballs presents the possibility of matching specific meteorites to specific asteroids, or at least to asteroids in the same stream and, therefore, presumably of the same composition. Although perhaps of limited practical value, the three meteorites with known orbits are all ordinary chondrites. To identify, in general, the taxonomic type of the parent asteroid, however, would be of great scientific interest since these most abundant meteorite types cannot be unambiguously spectrally matched to an asteroid type. The H5 Pribram meteorite and asteroid 4486 (unclassified) are not part of a stream, but travel in fairly similar orbits. The LL5 Innisfree meteorite is orbitally similar to asteroid 1989DA (unclassified), and both are members of a fourth stream (delta) defined by five meteorite-dropping fireballs and this one asteroid. The H5 Lost City meteorite is orbitally similar to 1980AA (S type), which is a member of stream gamma defined by four asteroids and four fireballs. Another asteroid in this stream is classified as an S type, another is QU, and the fourth is unclassified. This stream suggests that ordinary chondrites should be associated with S (and/or Q) asteroids. Two of the known four V type asteroids belong to another stream, beta, defined by five asteroids and four meteorite-dropping (but unrecovered) fireballs, making it the most probable source of the eucrites. The final stream, alpha, defined by five asteroids and three fireballs is of unknown composition since no meteorites have been recovered and only one asteroid has an ambiguous classification of QRS. If this stream, or any other as yet undiscovered ones, were found to be composed of a more practical material (e.g., water or metalrich), then recovery of the associated meteorites would provide an opportunity for in-hand analysis of a potential

  19. Do asteroids have satellites

    International Nuclear Information System (INIS)

    Weidenschilling, S.J.; Paolicchi, P.; Zappala, V.

    1989-01-01

    A substantial body of indirect evidence suggests that some asteroids have satelities, although none has been detected unambiguously. Collisions between asteroids provide physically plausible mechanisms for the production of binaries, but these operate with low probability; only a small minority of asteroids are likely to have satellites. The abundance of binary asteroids can constrain the collisional history of the entire belt population. The allowed angular momentum of binaries and their rate of tidal evolution limit separations to no more than a few tens of the primary's radii. Their expected properties are consistent with failure to detect them by current imaging techniques

  20. VL1 Digs A Deep Hole On Mars

    Science.gov (United States)

    1977-01-01

    VIKING LANDER DIGS A DEEP HOLE ON MARS -- This six-inch-deep, 12- inch-wide, 29-inch-long hole was dug Feb. 12 and 14 by Viking Lander 1 as the first sequence in an attempt to reach a foot beneath the surface of the red planet. The activity is in the same area where Lander 1 acquired its first soil samples last July. The trench was dug by repeatedly backhoeing in a left-right-center pattern. The backhoe teeth produced the small parallel ridges at the far end of the trench (upper left). The larger ridges running the length of the trench are material left behind during the backhoe operation. What appears to be small rocks along the ridges and in the soil at the near end of the trench are really small dirt clods. The clods and the steepness of the trench walls indicate the material is cohesive and behaves something like ordinary flour. After a later sequence, to be performed March 1 and 2, a soil sample will be taken from the bottom of the trench for inorganic soil analysis and later for biology analysis. Information about the soil taken from the bottom of the trench may help explain the weathering process on Mars and may help resolve the dilemma created by Viking findings that first suggest but then cast doubt on the possibility of life in the Martian soil. The trench shown here is a result of one of the most complex command sequences yet performed by the lander. Viking l has been operating at Chryse Planitia on Mars since it landed July 20, 1976.

  1. Asteroids mass determination

    International Nuclear Information System (INIS)

    Hoffmann, M.

    1989-01-01

    Basic methods for asteroid mass determinations and their errors are discussed. New results and some current developments in the astrometric method are reviewed. New methods and techniques, such as electronic imaging, radar ranging and space probes are becoming important for asteroid mass determinations. Mass and density estimations on rotational properties and possible satelites are also discussed

  2. Smarter shovels dig and load more efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Fiscor, S.

    2009-04-15

    Digital drive upgrades allow older shovels to power through the bank smoothly while improving safety and reliability. The Mine Technology Group of Flanders Electric has pioneered an effort to offer open architecture for shovel electrics by installing Power Performance Digital Drive controls to motors to ensure peak power is provided during the digging process. The new system also has a Smart Fault Recognition system to power down in a controlled fashion. The upgrades have been fitted to Asarco's shovel for use in coal mining operations. 1 fig., 1 photos. 4 figs.

  3. Rising Above the Storm: DIG TEXAS

    Science.gov (United States)

    Ellins, K. K.; Miller, K. C.; Bednarz, S. W.; Mosher, S.

    2011-12-01

    For a decade Texas educators, scientists and citizens have shown a commitment to earth science education through planning at the national and state levels, involvement in earth science curriculum and teacher professional development projects, and the creation of a model senior level capstone Earth and Space Science course first offered in 2010 - 2011. The Texas state standards for Earth and Space Science demonstrate a shift to rigorous content, career relevant skills and use of 21st century technology. Earth and Space Science standards also align with the Earth Science, Climate and Ocean Literacy framework documents. In spite of a decade of progress K-12 earth science education in Texas is in crisis. Many school districts do not offer Earth and Space Science, or are using the course as a contingency for students who fail core science subjects. The State Board for Educator Certification eliminated Texas' secondary earth science teacher certification in 2009, following the adoption of the new Earth and Space Science standards. This makes teachers with a composite teacher certification (biology, physics and chemistry) eligible to teach Earth and Space Science, as well other earth science courses (e.g., Aquatic Science, Environmental Systems/Science) even if they lack earth science content knowledge. Teaching materials recently adopted by the State Board of Education do not include Earth and Space Science resources. In July 2011 following significant budget cuts at the 20 Education Service Centers across Texas, the Texas Education Agency eliminated key staff positions in its curriculum division, including science. This "perfect storm" has created a unique opportunity for a university-based approach to confront the crisis in earth science education in Texas which the Diversity and Innovation in the Geosciences (DIG) TEXAS alliance aims to fulfill. Led by the Texas A&M University College of Geosciences and The University of Texas Jackson School of Geosciences, with

  4. Spacecraft exploration of asteroids

    International Nuclear Information System (INIS)

    Veverka, J.; Langevin, Y.; Farquhar, R.; Fulchignoni, M.

    1989-01-01

    After two decades of spacecraft exploration, we still await the first direct investigation of an asteroid. This paper describes how a growing international interest in the solar system's more primitive bodies should remedy this. Plans are under way in Europe for a dedicated asteroid mission (Vesta) which will include multiple flybys with in situ penetrator studies. Possible targets include 4 Vesta, 8 Flora and 46 Hestia; launch its scheduled for 1994 or 1996. In the United States, NASA plans include flybys of asteroids en route to outer solar system targets

  5. Asteroid clusters similar to asteroid pairs

    Science.gov (United States)

    Pravec, P.; Fatka, P.; Vokrouhlický, D.; Scheeres, D. J.; Kušnirák, P.; Hornoch, K.; Galád, A.; Vraštil, J.; Pray, D. P.; Krugly, Yu. N.; Gaftonyuk, N. M.; Inasaridze, R. Ya.; Ayvazian, V. R.; Kvaratskhelia, O. I.; Zhuzhunadze, V. T.; Husárik, M.; Cooney, W. R.; Gross, J.; Terrell, D.; Világi, J.; Kornoš, L.; Gajdoš, Š.; Burkhonov, O.; Ehgamberdiev, Sh. A.; Donchev, Z.; Borisov, G.; Bonev, T.; Rumyantsev, V. V.; Molotov, I. E.

    2018-04-01

    We studied the membership, size ratio and rotational properties of 13 asteroid clusters consisting of between 3 and 19 known members that are on similar heliocentric orbits. By backward integrations of their orbits, we confirmed their cluster membership and estimated times elapsed since separation of the secondaries (the smaller cluster members) from the primary (i.e., cluster age) that are between 105 and a few 106 years. We ran photometric observations for all the cluster primaries and a sample of secondaries and we derived their accurate absolute magnitudes and rotation periods. We found that 11 of the 13 clusters follow the same trend of primary rotation period vs mass ratio as asteroid pairs that was revealed by Pravec et al. (2010). We generalized the model of the post-fission system for asteroid pairs by Pravec et al. (2010) to a system of N components formed by rotational fission and we found excellent agreement between the data for the 11 asteroid clusters and the prediction from the theory of their formation by rotational fission. The two exceptions are the high-mass ratio (q > 0.7) clusters of (18777) Hobson and (22280) Mandragora for which a different formation mechanism is needed. Two candidate mechanisms for formation of more than one secondary by rotational fission were published: the secondary fission process proposed by Jacobson and Scheeres (2011) and a cratering collision event onto a nearly critically rotating primary proposed by Vokrouhlický et al. (2017). It will have to be revealed from future studies which of the clusters were formed by one or the other process. To that point, we found certain further interesting properties and features of the asteroid clusters that place constraints on the theories of their formation, among them the most intriguing being the possibility of a cascade disruption for some of the clusters.

  6. Asteroid taxonomic classifications

    International Nuclear Information System (INIS)

    Tholen, D.J.

    1989-01-01

    This paper reports on three taxonomic classification schemes developed and applied to the body of available color and albedo data. Asteroid taxonomic classifications according to two of these schemes are reproduced

  7. Distant asteroids and Chiron

    International Nuclear Information System (INIS)

    French, L.M.; Vilas, F.; Hartmann, W.K.; Tholen, D.J.

    1989-01-01

    Knowledge of the physical properties of distant asteroids (a>3.3 AU) has grown dramatically over the past five years, due to systematic compositional and lightcurve studies. Most of these objects have red, dark surfaces, and their spectra show a reddening in spectral slope with heliocentric distance implying a change in surface composition. Trojans for which near-opposition phase curve information is available appear to show little or no opposition effect, unlike any dark solar system objects. The lightcurve amplitudes of Trojan and Hilda asteroids imply significantly more elongated shapes for these groups than for main-belt asteroids of comparable size. These recent observations are reviewed in the context of their implications for the formation and subsequent evolution of the distant asteroids, and their interrelations with the main belt, Chiron and comets

  8. Asteroid rotation. IV

    International Nuclear Information System (INIS)

    Harris, A.W.; Young, J.W.

    1983-01-01

    The results from the year 1979 of an ongoing program of asteroid photometry at Table Mountain Observatory are presented. The results for 53 asteroids are summarized in a table, showing the number, name, opposition date, taxonomic class, diameter, absolute magnitude, mean absolute magnitude at zero phase angle and values of the absolute magnitude and linear phase coefficient derived from it, the rotation period in hours, peak-to-peak amplitude of variation, difference between mean and maximum brightness, and reliability index. Another table presents data on aspect and comparison stars, including brightness and distance data. Reliable rotation periods are reported for 22 asteroids for which no previous values are known. For seven asteroids, periods are reported which are revisions of previously reported values

  9. 24-COLOR ASTEROID SURVEY

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset is comprised of asteroid flux data measured in 26 filters using the McCord dual beam photometer, and covering the range 0.32 - 1.08 microns for 285...

  10. Near Earth Asteroid Scout

    Data.gov (United States)

    National Aeronautics and Space Administration — Near-Earth Asteroid Scout, or NEA Scout, is a 6U CubeSat developed jointly between NASA’s Marshall Space Flight Center and the Jet Propulsion Laboratory. NASA...

  11. 52-COLOR ASTEROID SURVEY

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains 52-color IR data of asteroids, taken using a double circularly variable filter. The short wavelength portion of the CVF covered the octave...

  12. Asteroids@Home

    Science.gov (United States)

    Durech, Josef; Hanus, J.; Vanco, R.

    2012-10-01

    We present a new project called Asteroids@home (http://asteroidsathome.net/boinc). It is a volunteer-computing project that uses an open-source BOINC (Berkeley Open Infrastructure for Network Computing) software to distribute tasks to volunteers, who provide their computing resources. The project was created at the Astronomical Institute, Charles University in Prague, in cooperation with the Czech National Team. The scientific aim of the project is to solve a time-consuming inverse problem of shape reconstruction of asteroids from sparse-in-time photometry. The time-demanding nature of the problem comes from the fact that with sparse-in-time photometry the rotation period of an asteroid is not apriori known and a huge parameter space must be densely scanned for the best solution. The nature of the problem makes it an ideal task to be solved by distributed computing - the period parameter space can be divided into small bins that can be scanned separately and then joined together to give the globally best solution. In the framework of the the project, we process asteroid photometric data from surveys together with asteroid lightcurves and we derive asteroid shapes and spin states. The algorithm is based on the lightcurve inversion method developed by Kaasalainen et al. (Icarus 153, 37, 2001). The enormous potential of distributed computing will enable us to effectively process also the data from future surveys (Large Synoptic Survey Telescope, Gaia mission, etc.). We also plan to process data of a synthetic asteroid population to reveal biases of the method. In our presentation, we will describe the project, show the first results (new models of asteroids), and discuss the possibilities of its further development. This work has been supported by the grant GACR P209/10/0537 of the Czech Science Foundation and by the Research Program MSM0021620860 of the Ministry of Education of the Czech Republic.

  13. Asteroid rotation rates

    International Nuclear Information System (INIS)

    Binzel, R.P.; Farinella, P.

    1989-01-01

    Within the last decade the data base of asteroid rotation parameters (rotation rates and lightcurve amplitudes) has become sufficiently large to identify some definite rends and properties which can help us to interpret asteroid collisional evolution. Many significant correlations are found between rotation parameters and diameter, with distinct changes occurring near 125 km. The size range, which is also the diameter above which self-gravity may become important, perhaps represents a division between surviving primordial asteroids and collisional fragments. A Maxwellian is able to fit the observed rotation rate distributions of asteroids with D>125 km, implying that their rotation rates may be determined by collisional evolution. Asteroids with D<125 km show an excess of slow rotators and their non-Maxwellian distributions suggests that their rotation rates are more strongly influenced by other processes, such as the distribution resulting from their formation in catastrophic disruption events. Other correlations observed in the data set include different mean rotation rates for C, S and M type asteroids implying that their surface spectra are indicative of bulk properties

  14. A shovel with a perforated blade reduces energy expenditure required for digging wet clay.

    Science.gov (United States)

    Harivanam, Sridhar; Marklin, Richard W; Papanek, Paula E; Cariapa, Vikram

    2010-08-01

    A shovel with a blade perforated with small holes was tested to see whether a worker would use less whole-body energy to dig wet clay than with a shovel with an opaque blade. A perforated shovel is hypothesized to require less whole-body energy on the basis of adhesion theory; a smaller surface area would require less physical effort to dig and release soil from the blade. The study involved 13 workers from an electric utility who dug wet clay with two 1.5-m long-handled point shovels, which differed only in blade design (perforated and opaque). Oxygen consumption was measured with a portable system while each worker dug wet clay at a self-regulated pace for 10 min. There was no significant difference in number of scoops dug during the 10-min sessions, but workers dug 9.5% more weight of clay with the perforated shovel than with the conventional shovel (404 kg vs. 369 kg, respectively). Furthermore, stable oxygen uptake normalized to weight of participant and to the weight of clay dug revealed that participants expended 11.7% less relative energy per kilogram of clay dug with the perforated shovel. A point shovel with a perforated blade is recommended for digging and shoveling wet clay. However, the extra weight that workers chose to dig with the perforated shovel may increase the loading on the spine and may offset the metabolic advantages. Manual shoveling is a common task, and workers may experience less whole-body and muscle fatigue when using a perforated shovel.

  15. Introduction to the Asteroids II data base

    International Nuclear Information System (INIS)

    Tedesco, E.F.

    1989-01-01

    The Asteroids II data base presented is a compilation of asteroid data. Included are asteroid names and discovery circumstances, proper elements and family identifications, asteroid lightcurve parameters, asteroid pole determinations, taxonomic classes, absolute magnitudes and slope parameters, UBV color indices, and albedos and diameters from the IRAS Asteroid and Comet Survey

  16. Impact-Actuated Digging Tool for Lunar Excavation, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Honeybee Robotics proposes to develop a vacuum compatible, impact-actuated digging tool for the excavation of frozen and compacted regolith on the lunar surface and...

  17. 2015 Barcelona Asteroid Day

    CERN Document Server

    Gritsevich, Maria; Palme, Herbert

    2017-01-01

    This volume is a compilation of the research presented at the International Asteroid Day workshop which was celebrated at Barcelona on June 30th, 2015. The proceedings discuss the beginning of a new era in the study and exploration of the solar system’s minor bodies. International Asteroid Day commemorates the Tunguska event of June 30th, 1908. The workshop’s goal was to promote the importance of dealing proactively with impact hazards from space. Multidisciplinary experts contributed to this discussion by describing the nature of comets and asteroids along with their offspring, meteoroids. New missions to return material samples of asteroids back to Earth such as Osiris-REx and Hayabusa 2, as well as projects like AIM and DART which will test impact deflection techniques for Potentially Hazardous Asteroids encounters were also covered. The proceedings include both an outreach level to popularize impact hazards and a scientific character which covers the latest knowledge on these topics, as well as offeri...

  18. Asteroid Composite Tape

    Science.gov (United States)

    1998-07-01

    This is a composite tape showing 10 short segments primarily about asteroids. The segments have short introductory slides, which include brief descriptions about the shots. The segments are: (1) Radar movie of asteroid 1620 Geographos; (2) Animation of the trajectories of Toutatis and Earth (3) Animation of a landing on Toutatis; (4) Simulated encounter of an asteroid with Earth, includes a simulated impact trajectory; (5) An animated overview of the Manrover vehicle; (6) The Near Earth Asteroid Tracking project, includes a photograph of USAF Station in Hawaii, and animation of Earth approaching 4179 Toutatis and the asteroid Gaspara; (7) live video of the anchor tests of the Champoleon anchoring apparatus; (8) a second live video of the Champoleon anchor tests showing anchoring spikes, and collision rings; (9) An animated segment with narration about the Stardust mission with sound, which describes the mission to fly close to a comet, and capture cometary material for return to Earth; (10) live video of the drop test of a Stardust replica from a hot air balloon; this includes sound but is not narrated.

  19. Asteroids - NeoWs API

    Data.gov (United States)

    National Aeronautics and Space Administration — NeoWs (Near Earth Object Web Service) is a RESTful web service for near earth Asteroid information. With NeoWs a user can: search for Asteroids based on their...

  20. Asteroids astronomical and geological bodies

    CERN Document Server

    Burbine, Thomas H

    2016-01-01

    Asteroid science is a fundamental topic in planetary science and is key to furthering our understanding of planetary formation and the evolution of the Solar System. Ground-based observations and missions have provided a wealth of new data in recent years, and forthcoming missions promise further exciting results. This accessible book presents a comprehensive introduction to asteroid science, summarising the astronomical and geological characteristics of asteroids. The interdisciplinary nature of asteroid science is reflected in the broad range of topics covered, including asteroid and meteorite classification, chemical and physical properties of asteroids, observational techniques, cratering, and the discovery of asteroids and how they are named. Other chapters discuss past, present and future space missions and the threat that these bodies pose for Earth. Based on an upper-level course on asteroids and meteorites taught by the author, this book is ideal for students, researchers and professional scientists ...

  1. Performance monitoring of electric shovels digging oil sands

    Energy Technology Data Exchange (ETDEWEB)

    Patnayak, S. [Alberta Univ., Edmonton, AB (Canada). Natural Resources Engineering Facility; Tannant, D.D. [Alberta Univ., Edmonton, AB (Canada). School of Mining and Petroleum Engineering; Parsons, I. [Syncrude Canada Ltd., Edmonton, AB (Canada). Edmonton Research Centre; Del Valle, V. [Syncrude Canada Ltd., Fort McMurray, AB (Canada)

    2005-07-01

    Some of the largest available mining equipment is used for oil sand mining operations. However, the performance of electric cable shovels varies with the diggability characteristics of the ground. In particular, oil sands diggability with cable shovels depends on structural geology, the depositional environment and geotechnical parameters. This paper described some of the key shovel performance indicators such as dig cycle time, digging energy and digging power. In winter, frost penetration can also affect oil sands diggability. The challenge of hard digging in oil sands is often addressed by blasting or ripping, which increases the cost of production and impedes productivity. The shovel performance is also influenced by other parameters such as operator skills, bucket and tooth design and shovel dipper trajectory. This paper demonstrated that hoist and crowd motor voltages and currents are useful in identifying the beginning and end of dig cycles. Performance indicators such as dig cycle time, hoist motor energy and power, and crowd motor energy and power were considered to assess material diggability. It was suggested that hoist power represents the ground diggability better than other performance indicators. 5 refs., 1 tab., 10 figs.

  2. The stability of some asteroids

    International Nuclear Information System (INIS)

    Vicente, R.O.

    1983-01-01

    The utilization of two different stability criteria, namely, Hill's modified stability criterium and the method of surface of section, has been employed for asteroid orbits. The idea is to compute different criteria of stability for the same asteroids in order to compare the results and see the practical interest of the computations for researches about evolutionary trends of individual asteroids, groups and families of asteroids. (Auth.)

  3. Geography of the asteroid belt

    Science.gov (United States)

    Zellner, B. H.

    1978-01-01

    The CSM classification serves as the starting point on the geography of the asteroid belt. Raw data on asteroid types are corrected for observational biases (against dark objects, for instance) to derive the distribution of types throughout the belt. Recent work on family members indicates that dynamical families have a true physical relationship, presumably indicating common origin in the breakup of a parent asteroid.

  4. Physical characterization of asteroid surfaces from photometric analysis

    International Nuclear Information System (INIS)

    Helfenstein, P.; Veverka, J.

    1989-01-01

    Rigorous photometric models, like Hapke's equation, can be applied to the analysis of disk-integrated phase curves in order to estimate a variety of regolith physical properties (average particle single-scattering albedo, particle transparency, soil compaction and large-scale roughness). Unfortunately, unambiguous interpretation is difficult due to uncertainties introduced by the irregular shapes of many asteroids and because Earth-based observations are often restricted to small phase angles (<30 degrees). In this chapter, the authors explore in detail how incomplete phase-angle coverage and nonsphericity of asteroids limits the reliable determination of Hapke's photometric parameters from asteroid phase curves. From obtainable Earth-based observations, it is possible to derive useful relative comparisons of single-scattering albedos, opposition-surge amplitudes, and regolith compaction states for different asteroids

  5. Test plan for dig-face characterization performance testing

    International Nuclear Information System (INIS)

    Josten, N.E.

    1993-09-01

    The dig-face characterization concept has been under development at the Idaho National Engineering Laboratory (INEL) since FY 1992 through the support of the Buried Waste Integrated Demonstration Program. A Dig-face Characterization System conducts continuous subsurface characterization simultaneously with retrieval of hazardous and radioactive waste from buried waste sites. The system deploys multiple sensors at the retrieval operation dig-face and collects data that provide a basis for detecting, locating, and identifying hazardous conditions before they are disturbed by the retrieval equipment. This test plan describes initial efforts to test the dig-face characterization concept at the INEL Cold Test Pit using a simplified prototype apparatus and off-the-shelf sensors. The Cold Test Pit is a simulated waste site containing hazardous and radioactive waste surrogates at known locations. Testing will be directed toward three generic characterization problems: metal detection, plume detection, and radioactive source detection. The prototype apparatus will gather data using magnetometers, a ground conductivity meter, a trace gas analyzer, and a gamma ray sensor during simulated retrieval of the surrogate waste materials. The data acquired by a dig-face characterization system are unique because of the high precision, high data density, and multiple viewpoints attainable through the dig-face deployment approach. The test plan establishes procedures for collecting and validating a representative dig-face characterization data set. Analysis of these data will focus on developing criteria for predicting the depth, location, composition, and other characteristics of the surrogate waste materials. If successful, this proof-of-concept exercise will provide a foundation for future development of a fully-operational system that is capable of operating on an actual waste site

  6. LISA and asteroids

    International Nuclear Information System (INIS)

    Vinet, Jean-Yves

    2006-01-01

    LISA is a joint ESA-NASA mission aiming for cosmic gravitational wave detection and analysis. We address here the question of a special kind of signal caused by asteroid encounters. We present a short theory of the detection of such signals

  7. Asteroids, meteorites, and comets

    CERN Document Server

    Elkins-Tanton, Linda T

    2010-01-01

    Asteroids, Comets, and Meteorites provides students, researchers, and general readers with the most up-to-date information on this fascinating field. From the days of the dinosaurs to our modern environment, this book explores all aspects of these cosmic invaders.

  8. Asteroid Kinetic Impactor Missions

    Science.gov (United States)

    Chesley, Steven

    2015-08-01

    Asteroid impact missions can be carried out as a relatively low-cost add-ons to most asteroid rendezvous missions and such impact experiments have tremendous potential, both scientifically and in the arena of planetary defense.The science returns from an impactor demonstration begin with the documentation of the global effects of the impact, such as changes in orbit and rotation state, the creation and dissipation of an ejecta plume and debris disk, and morphological changes across the body due to the transmission of seismic waves, which might induce landslides and toppling of boulders, etc. At a local level, an inspection of the impact crater and ejecta blanket reveals critical material strength information, as well as spectral differences between the surface and subsurface material.From the planetary defense perspective, an impact demonstration will prove humankind’s capacity to alter the orbit of a potentially threatening asteroid. This technological leap comes in two parts. First, terminal guidance systems that can deliver an impactor with small errors relative to the ~100-200 meter size of a likely impactor have yet to be demonstrated in a deep space environment. Second, the response of an asteroid to such an impact is only understood theoretically due to the potentially significant dependence on the momentum carried by escaping ejecta, which would tend to enhance the deflection by tens of percent and perhaps as much as a factor of a few. A lack of validated understanding of momentum enhancement is a significant obstacle in properly sizing a real-world impactor deflection mission.This presentation will describe the drivers for asteroid impact demonstrations and cover the range of such concepts, starting with ESA’s pioneering Don Quijote mission concept and leading to a brief description of concepts under study at the present time, including the OSIRIS-REx/ISIS, BASiX/KIX and AIM/DART (AIDA) concepts.

  9. ASTROMETRIC MASSES OF 26 ASTEROIDS AND OBSERVATIONS ON ASTEROID POROSITY

    International Nuclear Information System (INIS)

    Baer, James; Chesley, Steven R.; Matson, Robert D.

    2011-01-01

    As an application of our recent observational error model, we present the astrometric masses of 26 main-belt asteroids. We also present an integrated ephemeris of 300 large asteroids, which was used in the mass determination algorithm to model significant perturbations from the rest of the main belt. After combining our mass estimates with those of other authors, we study the bulk porosities of over 50 main-belt asteroids and observe that asteroids as large as 300 km in diameter may be loose aggregates. This finding may place specific constraints on models of main-belt collisional evolution. Additionally, we observe that C-group asteroids tend to have significantly higher macroporosity than S-group asteroids.

  10. Radar observations of asteroids

    International Nuclear Information System (INIS)

    Ostro, S.J.

    1989-01-01

    This paper describes echoes from 33 main-belt asteroids (MBAs) and 19 near-Earth asteroids (NEAs) have provided a wealth of new information about these objects such as sizes, shapes, spin vectors, and such surface characteristics as decimeter-scale morphology, topographic relief, regolith porosity and metal concentrations. On average, small NEAs are much rougher at decimeter scales than MBAs, comets or terrestrial planets. Some of the largest MBAs (e.g., 1 Ceres and 2 Pallas ) are smoother than the moon at decimeter scales but much rougher than the Moon at some much larger scale. There is at least a five-fold variation in the radar albedos of MBAs, implying substantial variations in the surface porosities or metal concentrations of these objects. The highest MBA albedo estimate, for 16 Psyche, is consistent with a metal concentration near unity and lunar porosities

  11. Earth's Trojan asteroid.

    Science.gov (United States)

    Connors, Martin; Wiegert, Paul; Veillet, Christian

    2011-07-27

    It was realized in 1772 that small bodies can stably share the same orbit as a planet if they remain near 'triangular points' 60° ahead of or behind it in the orbit. Such 'Trojan asteroids' have been found co-orbiting with Jupiter, Mars and Neptune. They have not hitherto been found associated with Earth, where the viewing geometry poses difficulties for their detection, although other kinds of co-orbital asteroid (horseshoe orbiters and quasi-satellites) have been observed. Here we report an archival search of infrared data for possible Earth Trojans, producing the candidate 2010 TK(7). We subsequently made optical observations which established that 2010 TK(7) is a Trojan companion of Earth, librating around the leading Lagrange triangular point, L(4). Its orbit is stable over at least ten thousand years.

  12. File list: Unc.Dig.05.AllAg.Intestinal_crypt [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Dig.05.AllAg.Intestinal_crypt mm9 Unclassified Digestive tract Intestinal crypt... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.Dig.05.AllAg.Intestinal_crypt.bed ...

  13. File list: His.Dig.50.AllAg.Intestine,_Small [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Dig.50.AllAg.Intestine,_Small hg19 Histone Digestive tract Intestine, Small htt...p://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Dig.50.AllAg.Intestine,_Small.bed ...

  14. Silicates in Alien Asteroids

    Science.gov (United States)

    2009-01-01

    This plot of data from NASA's Spitzer Space Telescopes shows that asteroid dust around a dead 'white dwarf' star contains silicates a common mineral on Earth. The data were taken primarily by Spitzer's infrared spectrograph, an instrument that breaks light apart into its basic constituents. The yellow dots show averaged data from the spectrograph, while the orange triangles show older data from Spitzer's infrared array camera. The white dwarf is called GD 40.

  15. Speckle interferometry of asteroids

    International Nuclear Information System (INIS)

    Drummond, J.

    1988-01-01

    By studying the image two-dimensional power spectra or autocorrelations projected by an asteroid as it rotates, it is possible to locate its rotational pole and derive its three axes dimensions through speckle interferometry under certain assumptions of uniform, geometric scattering, and triaxial ellipsoid shape. However, in cases where images can be reconstructed, the need for making the assumptions is obviated. Furthermore, the ultimate goal for speckle interferometry of image reconstruction will lead to mapping albedo features (if they exist) as impact areas or geological units. The first glimpses of the surface of an asteroid were obtained from images of 4 Vesta reconstructed from speckle interferometric observations. These images reveal that Vesta is quite Moon-like in having large hemispheric-scale albedo features. All of its lightcurves can be produced from a simple model developed from the images. Although undoubtedly more intricate than the model, Vesta's lightcurves can be matched by a model with three dark and four bright spots. The dark areas so dominate one hemisphere that a lightcurve minimum occurs when the maximum cross-section area is visible. The triaxial ellipsoid shape derived for Vesta is not consistent with the notion that the asteroid has an equilibrium shape in spite of its having apparently been differentiated

  16. Asteroids, Comets, Meteors 2014

    Science.gov (United States)

    Muinonen, K.; Penttilä, A.; Granvik, M.; Virkki, A.; Fedorets, G.; Wilkman, O.; Kohout, T.

    2014-08-01

    Asteroids, Comets, Meteors focuses on the research of small Solar System bodies. Small bodies are the key to understanding the formation and evolution of the Solar System, carrying signals from pre-solar times. Understanding the evolution of the Solar System helps unveil the evolution of extrasolar planetary systems. Societally, small bodies will be important future resources of minerals. The near-Earth population of small bodies continues to pose an impact hazard, whether it be small pieces of falling meteorites or larger asteroids or cometary nuclei capable of causing global environmental effects. The conference series entitled ''Asteroids, Comets, Meteors'' constitutes the leading international series in the field of small Solar System bodies. The first three conferences took place in Uppsala, Sweden in 1983, 1985, and 1989. The conference is now returning to Nordic countries after a quarter of a century. After the Uppsala conferences, the conference has taken place in Flagstaff, Arizona, U.S.A. in 1991, Belgirate, Italy in 1993, Paris, France in 1996, Ithaca, New York, U.S.A. in 1999, in Berlin, Germany in 2002, in Rio de Janeiro, Brazil in 2005, in Baltimore, Maryland, U.S.A. in 2008, and in Niigata, Japan in 2012. ACM in Helsinki, Finland in 2014 will be the 12th conference in the series.

  17. Comet or Asteroid?

    Science.gov (United States)

    1997-11-01

    When is a minor object in the solar system a comet? And when is it an asteroid? Until recently, there was little doubt. Any object that was found to display a tail or appeared diffuse was a comet of ice and dust grains, and any that didn't, was an asteroid of solid rock. Moreover, comets normally move in rather elongated orbits, while most asteroids follow near-circular orbits close to the main plane of the solar system in which the major planets move. However, astronomers have recently discovered some `intermediate' objects which seem to possess properties that are typical for both categories. For instance, a strange object (P/1996 N2 - Elst-Pizarro) was found last year at ESO ( ESO Press Photo 36/96 ) which showed a cometary tail, while moving in a typical asteroidal orbit. At about the same time, American scientists found another (1996 PW) that moved in a very elongated comet-type orbit but was completely devoid of a tail. Now, a group of European scientists, by means of observations carried out at the ESO La Silla observatory, have found yet another object that at first appeared to be one more comet/asteroid example. However, continued and more detailed observations aimed at revealing its true nature have shown that it is most probably a comet . Consequently, it has received the provisional cometary designation P/1997 T3 . The Uppsala-DLR Trojan Survey Some time ago, Claes-Ingvar Lagerkvist (Astronomical Observatory, Uppsala, Sweden), in collaboration with Gerhard Hahn, Stefano Mottola, Magnus Lundström and Uri Carsenty (DLR, Institute of Planetary Exploration, Berlin, Germany), started to study the distribution of asteroids near Jupiter. They were particularly interested in those that move in orbits similar to that of Jupiter and which are located `ahead' of Jupiter in the so-called `Jovian L4 Lagrangian point'. Together with those `behind' Jupiter, these asteroids have been given the names of Greek and Trojan Heroes who participated in the famous Trojan war

  18. An overview of the asteroids

    International Nuclear Information System (INIS)

    Binzel, R.P.

    1989-01-01

    An introduction and overview of the field of asteroid science is presented, highlighting the accomplishments of the 1980s. The development and application of many observational techniques and data from the Infrared Astronomical Satellite have greatly increased our knowledge of asteroid physical properties. New scenarios for understanding the chemical diversity and dynamical structure of asteroids have emerged. New insights have been gained toward understanding their origin and interrelations with meteorites and comets. Suggestions and speculations are offered on future research directions

  19. The first retrograde Trojan asteroid

    Science.gov (United States)

    Wiegert, Paul; Connors, Martin; Veillet, Christian

    2018-04-01

    There are about six thousand asteroids which share Jupiter's orbit around the Sun. Called the 'Trojan asteroids', they co-exist easily with this giant planet because they travel in the same direction as it ('direct' or 'prograde' motion), and remain roughly 60 degrees ahead of or behind it in its orbit. Newly discovered asteroid 2015 BZ509 is on a retrograde orbit, but is nonetheless in a state dynamically analogous to that of the prograde Trojans. The discovery circumstances and the nature of the motion of this curious asteroid -the first of its kind- will be outlined.

  20. Asteroid results from the IRAS survey

    International Nuclear Information System (INIS)

    Veeder, G.J.; Tedesco, E.F.; Matson, D.L.

    1989-01-01

    This paper reports that the IRAS Asteroid and Comet Survey yield a data base of infrared flux densities for 1811 individual asteroids. Albedos and diameters for these have been derived via a standard thermal model. IRAS sampled a large number of small asteroids and detected many dark asteroids in the outer belt. High-albedo asteroids remain rare. Observations of the brighter asteroids at multiple wavelengths shows the expected range of color temperatures through the main belt

  1. AIDA: Asteroid Impact & Deflection Assessment

    Science.gov (United States)

    Cheng, A. F.; Galvez, A.; Carnelli, I.; Michel, P.; Rivkin, A.; Reed, C.

    2012-12-01

    To protect the Earth from a hazardous asteroid impact, various mitigation methods have been proposed, including deflection of the asteroid by a spacecraft impact. AIDA, consisting of two mission elements, the Double Asteroid Redirection Test (DART) and the Asteroid Impact Monitoring (AIM) mission, is a demonstration of asteroid deflection. To date, there has been no such demonstration, and there is major uncertainty in the result of a spacecraft impact onto an asteroid, that is, the amount of deflection produced by a given momentum input from the impact. This uncertainty is in part due to unknown physical properties of the asteroid surface, such as porosity and strength, and in part due to poorly understood impact physics such that the momentum carried off by ejecta is highly uncertain. A first mission to demonstrate asteroid deflection would not only be a major step towards gaining the capability to mitigate an asteroid hazard, but in addition it would return unique information on an asteroid's strength, other surface properties, and internal structure. This information return would be highly relevant to future human exploration of asteroids. We report initial results of the AIDA joint mission concept study undertaken by the Johns Hopkins Applied Physics Laboratory and ESA with support from NASA centers including Goddard, Johnson and Jet Propulsion Laboratory. For AIDA, the DART spacecraft impactor study is coordinated with an ESA study of the AIM mission, which would rendezvous with the same asteroid to measure effects of the impact. Unlike the previous Don Quijote mission study performed by ESA in 2005-2007, DART envisions an impactor spacecraft to intercept the secondary member of a binary near-Earth asteroid. DART includes ground-based observations to measure the deflection independently of the rendezvous spacecraft observations from AIM, which also measures deflection and provides detailed characterization of the target asteroid. The joint mission AIDA

  2. In-Situ Electrokinetic Remediation for Metal Contaminated Soils

    Science.gov (United States)

    2001-03-01

    phytoremediation , and electrokinetic extraction. The US Army Environmental Center (USAEC) and Engineer Research and Development Center (ERDC...California (CA) List Metals: Antimony, arsenic, barium, beryllium, cadmium, chromium, cobalt, copper, lead, mercury , molybdenum, nickel, selenium...Comparison Technologies with which electrokinetic remediation must compete are "Dig and Haul", Soil Washing, and Phytoremediation . "Dig and haul

  3. Origin of the asteroid belt

    International Nuclear Information System (INIS)

    Wetherill, G.W.

    1989-01-01

    Earlier work and concepts relevant to the origin of the asteroid belt are reviewed and considered in the context of the more general question of solar system origin. Several aspects of asteroidal origin by accumulation of smaller bodies have been addressed by new dynamic studies. Numerical and analytical solutions of the dynamical theory of planetesimal accumulation are characterized by a bifurcation into runaway and nonrunaway solutions. The differences in time scales resulting from runaway and nonrunaway growth can be more important than conventional time scale differences determined by heliocentric distances. This introduces new possibilities, e.g., planetary accumulation may be more rapid at the distance of Jupiter than in the asteroid belt, thus permitting Jupiter to control asteroidal growth. Although alternatives must be seriously considered, the most promising approach to asteroidal origin is one in which the initial surface density of the solar nebula varied smoothly between the terrestrial and giant-planet region. In the absence of external perturbations, it is found that runaway growth of excessively large asteroids would then occur on <1 Myr, but fairly modest external perturbations by Jupiter, Saturn or other perturbers, resulting in eccentricities ∼0.01 may quench runaways, truncate asteroidal growth at their present size, and then initiate the necessary loss of asteroidal material by mutual fragmentation

  4. Asteroid electrostatic instrumentation and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Aplin, K L; Bowles, N E; Urbak, E [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Keane, D; Sawyer, E C, E-mail: k.aplin1@physics.ox.ac.uk [RAL Space, R25, Harwell Oxford, Didcot OX11 0QX (United Kingdom)

    2011-06-23

    Asteroid surface material is expected to become photoelectrically charged, and is likely to be transported through electrostatic levitation. Understanding any movement of the surface material is relevant to proposed space missions to return samples to Earth for detailed isotopic analysis. Motivated by preparations for the Marco Polo sample return mission, we present electrostatic modelling for a real asteroid, Itokawa, for which detailed shape information is available, and verify that charging effects are likely to be significant at the terminator and at the edges of shadow regions for the Marco Polo baseline asteroid, 1999JU3. We also describe the Asteroid Charge Experiment electric field instrumentation intended for Marco Polo. Finally, we find that the differing asteroid and spacecraft potentials on landing could perturb sample collection for the short landing time of 20min that is currently planned.

  5. Evolution of comets into asteroids

    International Nuclear Information System (INIS)

    Weissman, P.R.; A'hearn, M.F.; Rickman, H.; Mcfadden, L.A.

    1989-01-01

    This paper presents observational evidence, together with recent theoretical developments, supporting the hypothesis that at least some asteroids might be extinct or dormant cometary nuclei. The observations include the discovery of a number of apparent asteroids in chaotic Jupiter-crossing orbits; the IRAS discovery of 1983 TB, an asteroid in the same orbit as the Geminid meteor shower; the apparent low activity levels determined for several short-period comet nuclei including Comet Halley; and observations of possible cometary activity in some earth-crossing asteroids. Theoretical developments include explorations of dynamical mechanisms capable of delivering main-belt asteroids into earth-crossing orbits, and an understanding of possible processes which may affect comets during their long residence in the Oort cloud and lead to the formation of nonvolatile crusts before and after they enter the planetary system. 143 refs

  6. Earthtech, Dig-Texas and Upward Bound: Outreach to At-Risk Students with Interdisciplinary STEM Activities

    Science.gov (United States)

    Olgin, J. G.; Güereque, M.; Pennington, D. D.; Everett, A.; Dixon, J. G.; Reyes, A.; Houser, P. I. Q.; Baker, J. A.; Stocks, E.; Ellins, K.

    2015-12-01

    The Geological Sciences department at the University of Texas at El Paso (UTEP) hosted the EarthTech outreach program - a one-week intensive summer camp for low-income, at-risk high school students. The EarthTech program engaged students in STEM activities from geological and environmental sciences. Developed and led by university student-mentors with guidance from a supervising faculty member, the course engaged Upward Bound students with lectures, interactive projects, and excursions to local ecological preserves and geological sites around El Paso, Texas. Topics covered plant and animal distribution and diversity, water and soil dynamics, evolution and paleontology, geohazards, and planetary science. Field trips were combined with hands-on activities, including activities from DIG Texas teaching modules. The NSF-funded DIG Texas Instructional Blueprints project is organizing vetted, high quality online educational resources and learning activities into teaching modules. The modules follow a storyline and demonstrate congruency with the Next Generation Science Standards. Selected DIG Texas resources were included in the daily curriculum to complement the field trip and other hands-on activities. EarthTech students created ESRI Online GIS story maps in which they showed the locations of the field trips, incorporated photographs they had taken, and provided written reflections about their camp experiences. The DIG Texas project evaluation collected survey and interview data from the university student mentors throughout the week to ascertain the efficacy of the program. This poster presentation will include an overview of the program, including examples of work and evaluation results.

  7. Compositional studies of primitive asteroids

    International Nuclear Information System (INIS)

    Vilas, F.

    1988-01-01

    The composition of primitive asteroids and their relationship to satellites in the solar system will be studied by analyzing existing narrowband charge coupled device (CCD) reflectance spectra, acquiring additional spectra of asteroids and small satellites in the 0.5 to 1.0 micrometer spectral range, and exploring possibilities for obtaining compositional information in the blue-UV spectral region. Comparison with laboratory spectra of terrestrial chlorites and serpentines (phyllosilicates) and the clay minerals found in carbonaceous chondrite meteorites will continue. During 1987, narrowband CCD reflectance spectra of 17 additional asteroids were acquired. These spectra and spectra of 34 other asteroids have been used primarily for two studies: weak absorption features similar to those due to Fe2(+) and Fe2(+) - Fe3(+) transitions in iron oxides f ound in terrestrial chlorites and serpentines and carbonaceous chondrites have been identified in some primitive asteroid spectra. There is a first indication that asteroids grouped by heliocentric distance show similar weak absorption features. Nonparametric statistics are being applied to test the hypothesis of discrete remnants of a gradation in composition of outer-belt asteroids

  8. Mine Planning for Asteroid Orebodies

    Science.gov (United States)

    Gertsch, L. S.; Gertsch, R. E.

    2000-01-01

    Given that an asteroid (or comet) has been determined to contain sufficient material of value to be potentially economic to exploit, a mining method must be selected and implemented. This paper discusses the engineering necessary to bring a mine online, and the opportunities and challenges inherent in asteroid mineral prospects. The very important step of orebody characterization is discussed elsewhere. The mining methods discussed here are based on enclosing the asteroid within a bag in some fashion, whether completely or partially. In general, asteroid mining methods based on bags will consist of the following steps. Not all will be required in every case, nor necessarily in this particular sequence. Some steps will be performed simultaneously. Their purpose is to extract the valuable material from the body of the asteroid in the most efficient, cost-effective manner possible. In approximate order of initiation, if not of conclusion, the steps are: 1. Tether anchoring to the asteroid. 2. Asteroid motion control. 3. Body/fragment restraint system placement. 4. Operations platform construction. 5. Bag construction. 6. Auxiliary and support equipment placement. 7. Mining operations. 8. Processing operations. 9. Product transport to markets.

  9. Near Earth Asteroid redirect missions based on gravity assist maneuver

    Science.gov (United States)

    Ledkov, Anton; Shustov, Boris M.; Eismont, Natan; Boyarsky, Michael; Nazirov, Ravil; Fedyaev, Konstantin

    maneuvers needed for hitting the target object. As additional option of planetary defense system construction the idea to redirect small near Earth asteroids onto the orbits resonance with the Earth orbit is explored. It is shown that it is possible to reach it by the use gravity assist maneuvers as it was described above by applying small velocity impulses to the asteroids. At least 11 asteroids were found demanded small enough delta-V for transferring them on such trajectories. After executing these maneuvers one can receive the system of asteroids approaching to the Earth practically each month with a possibility to use them as projectiles or for the purposes of delivering to the Earth their soil samples.

  10. Asteroid named after CAS scientist

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ An asteroid has been named after CAS astronomy historian XI Zezong with the approval of the International Minor Planet Nomenclature Committee (IMPNC), announced China's National Astronomical Observatories at CAS (NAOC) on 17 August.

  11. Spectral properties of binary asteroids

    Science.gov (United States)

    Pajuelo, Myriam; Birlan, Mirel; Carry, Benoît; DeMeo, Francesca E.; Binzel, Richard P.; Berthier, Jérôme

    2018-04-01

    We present the first attempt to characterize the distribution of taxonomic class among the population of binary asteroids (15% of all small asteroids). For that, an analysis of 0.8-2.5{μ m} near-infrared spectra obtained with the SpeX instrument on the NASA/IRTF is presented. Taxonomic class and meteorite analog is determined for each target, increasing the sample of binary asteroids with known taxonomy by 21%. Most binary systems are bound in the S-, X-, and C- classes, followed by Q and V-types. The rate of binary systems in each taxonomic class agrees within uncertainty with the background population of small near-Earth objects and inner main belt asteroids, but for the C-types which are under-represented among binaries.

  12. Special issue on asteroids - Introduction

    Science.gov (United States)

    Novaković, Bojan; Hsieh, Henry H.; Gronchi, Giovanni F.

    2018-04-01

    The articles in this special issue are devoted to asteroids, small solar system bodies that primarily populate a region between the orbits of Mars and Jupiter, known as the asteroid belt, but can also be found throughout the Solar System. Asteroids are considered to be a key to understanding the formation and evolution of our planetary system. Their properties allow us to test current theoretical models and develop new theoretical concepts pertaining to evolutionary processes in the Solar System. There have been major advances in asteroid science in the last decade, and that trend continues. Eighteen papers accepted for this special issue cover a wide range of asteroid-related subjects, pushing the boundaries of our understanding of these intriguing objects even further. Here we provide the reader with a brief overview of these thrilling papers, with an invitation for interested scientists to read each work in detail for a better understanding of these recent cutting edge results. As many topics in asteroid science remain open challenges, we hope that this special issue will be an important reference point for future research on this compelling topic.

  13. Asteroids: up close and personal

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, Clark R. [Southwest Research Institute (United States)

    2001-06-01

    Think of our solar system. The Sun, the Moon and the nine planets come to mind first, followed by the moons of other planets and other small bodies like asteroids. In 1991, almost 30 years after planetary exploration began, an asteroid was visited by a passing spacecraft for the first time. Nearly another decade elapsed before the first dedicated asteroid mission went into orbit around Eros, a city-sized object some 34 km long. And earlier this year, the NEAR, Shoemaker spacecraft daringly descended to the surface of Eros and landed safely. Asteroids have been pushed to the tail-end of the itinerary of solar-system exploration because of their diminutive sizes. Indeed, the wealth of low-gravity phenomena associated with asteroids has captured the imagination of both researchers and the public alike. In the June issue of Physics World Clark R Chapman of the Southwest Research Institute, US, explains how the landing of a spacecraft on the asteroid Eros earlier this year has given space scientists the best view yet of small planetary bodies and has opened a new window on the solar system. (U.K.)

  14. Developing an Asteroid Rotational Theory

    Science.gov (United States)

    Geis, Gena; Williams, Miguel; Linder, Tyler; Pakey, Donald

    2018-01-01

    The goal of this project is to develop a theoretical asteroid rotational theory from first principles. Starting at first principles provides a firm foundation for computer simulations which can be used to analyze multiple variables at once such as size, rotation period, tensile strength, and density. The initial theory will be presented along with early models of applying the theory to the asteroid population. Early results confirm previous work by Pravec et al. (2002) that show the majority of the asteroids larger than 200m have negligible tensile strength and have spin rates close to their critical breakup point. Additionally, results show that an object with zero tensile strength has a maximum rotational rate determined by the object’s density, not size. Therefore, an iron asteroid with a density of 8000 kg/m^3 would have a minimum spin period of 1.16h if the only forces were gravitational and centrifugal. The short-term goal is to include material forces in the simulations to determine what tensile strength will allow the high spin rates of asteroids smaller than 150m.

  15. ASTEROID POLARIMETRIC DATABASE V6.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The Asteroid Polarimetric Database (APD) is a collection of asteroid polarimetry results compiled by D.F. Lupishko and S.V. Vasiliev of Karazin Kharkiv National...

  16. ASTEROID PHOTOMETRIC CATALOG V1.1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Asteroid Photometric Catalog (3rd update), Lagerkvist, et.al., 1993 [LAGERKVISTETAL1993], is a compilation of all asteroid lightcurve photometry published up to...

  17. Reflectance spectroscopy and asteroid surface mineralogy

    International Nuclear Information System (INIS)

    Gaffey, M.J.; Bell, J.F.; Cruikshank, D.P.

    1989-01-01

    Information available from reflectance spectroscopy on the surface mineralogy of asteroids is discussed. Current spectral interpretive procedures used in the investigations of asteroid mineralogy are described. Present understanding of the nature and history of asteroids is discussed together with some still unresolved issues such as the source of ordinary chondrites. 100 refs

  18. File list: ALL.Dig.10.AllAg.GIST-48 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Dig.10.AllAg.GIST-48 hg19 All antigens Digestive tract GIST-48 SRX825987,SRX023...216,SRX023215,SRX825986 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Dig.10.AllAg.GIST-48.bed ...

  19. File list: ALL.Dig.50.AllAg.GIST-48 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Dig.50.AllAg.GIST-48 hg19 All antigens Digestive tract GIST-48 SRX825987,SRX023...216,SRX023215,SRX825986 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Dig.50.AllAg.GIST-48.bed ...

  20. File list: ALL.Dig.20.AllAg.GIST-48 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Dig.20.AllAg.GIST-48 hg19 All antigens Digestive tract GIST-48 SRX825987,SRX023...216,SRX825986,SRX023215 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Dig.20.AllAg.GIST-48.bed ...

  1. File list: Oth.Dig.10.Epitope_tags.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.10.Epitope_tags.AllCell mm9 TFs and others Epitope tags Digestive tract SRX...365692 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Dig.10.Epitope_tags.AllCell.bed ...

  2. File list: Oth.Dig.20.Epitope_tags.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.20.Epitope_tags.AllCell mm9 TFs and others Epitope tags Digestive tract SRX...365692 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Dig.20.Epitope_tags.AllCell.bed ...

  3. File list: Pol.Dig.05.RNA_Polymerase_III.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Dig.05.RNA_Polymerase_III.AllCell mm9 RNA polymerase RNA Polymerase III Digesti...ve tract http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Dig.05.RNA_Polymerase_III.AllCell.bed ...

  4. File list: Pol.Dig.50.RNA_Polymerase_III.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Dig.50.RNA_Polymerase_III.AllCell mm9 RNA polymerase RNA Polymerase III Digesti...ve tract http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Dig.50.RNA_Polymerase_III.AllCell.bed ...

  5. File list: Pol.Dig.20.RNA_Polymerase_II.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Dig.20.RNA_Polymerase_II.AllCell mm9 RNA polymerase RNA Polymerase II Digestive... tract SRX112957,SRX143802 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Dig.20.RNA_Polymerase_II.AllCell.bed ...

  6. File list: Pol.Dig.20.RNA_polymerase_III.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Dig.20.RNA_polymerase_III.AllCell hg19 RNA polymerase RNA polymerase III Digest...ive tract http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Dig.20.RNA_polymerase_III.AllCell.bed ...

  7. File list: Oth.Dig.50.AllAg.Intestine,_Small [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.50.AllAg.Intestine,_Small hg19 TFs and others Digestive tract Intestine, Sm...all http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Dig.50.AllAg.Intestine,_Small.bed ...

  8. File list: InP.Dig.05.AllAg.Intestine,_Small [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Dig.05.AllAg.Intestine,_Small hg19 Input control Digestive tract Intestine, Sma...ll http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.Dig.05.AllAg.Intestine,_Small.bed ...

  9. File list: Unc.Dig.20.AllAg.Intestinal_villus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Dig.20.AllAg.Intestinal_villus mm9 Unclassified Digestive tract Intestinal vill...us SRX365695 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.Dig.20.AllAg.Intestinal_villus.bed ...

  10. File list: Pol.Dig.50.AllAg.Intestinal_villus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Dig.50.AllAg.Intestinal_villus mm9 RNA polymerase Digestive tract Intestinal vi...llus http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Dig.50.AllAg.Intestinal_villus.bed ...

  11. File list: InP.Dig.50.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Dig.50.AllAg.Intestines mm9 Input control Digestive tract Intestines ERX040294,...06,ERX040282,ERX040311,ERX040301,ERX040310,ERX040313,ERX040297,ERX040304,ERX040284 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Dig.50.AllAg.Intestines.bed ...

  12. File list: Oth.Dig.20.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.20.AllAg.Intestines mm9 TFs and others Digestive tract Intestines SRX143801...,SRX1431656 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Dig.20.AllAg.Intestines.bed ...

  13. File list: Pol.Dig.10.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Dig.10.AllAg.Intestines mm9 RNA polymerase Digestive tract Intestines SRX112957...,SRX143802 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Dig.10.AllAg.Intestines.bed ...

  14. File list: NoD.Dig.05.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Dig.05.AllAg.Intestines mm9 No description Digestive tract Intestines ERX421330...,ERX421334,ERX421319,ERX421323,ERX421333,ERX421324,ERX421320,ERX421321,ERX421336 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/NoD.Dig.05.AllAg.Intestines.bed ...

  15. File list: InP.Dig.50.AllAg.Intestinal_villus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Dig.50.AllAg.Intestinal_villus mm9 Input control Digestive tract Intestinal vil...lus SRX112512,SRX028556,SRX1141901,SRX193725 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Dig.50.AllAg.Intestinal_villus.bed ...

  16. File list: ALL.Dig.20.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Dig.20.AllAg.Intestines mm9 All antigens Digestive tract Intestines SRX191044,S...185803,ERX040309,ERX040302,ERX040313,ERX040297,ERX040283,ERX040300,ERX040284 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Dig.20.AllAg.Intestines.bed ...

  17. File list: DNS.Dig.20.AllAg.Intestine,_Small [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Dig.20.AllAg.Intestine,_Small mm9 DNase-seq Digestive tract Intestine, Small ht...tp://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.Dig.20.AllAg.Intestine,_Small.bed ...

  18. File list: ALL.Dig.10.AllAg.Intestine,_Small [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Dig.10.AllAg.Intestine,_Small mm9 All antigens Digestive tract Intestine, Small...4,SRX885798,SRX885799 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Dig.10.AllAg.Intestine,_Small.bed ...

  19. File list: ALL.Dig.10.AllAg.Intestinal_adenoma [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Dig.10.AllAg.Intestinal_adenoma mm9 All antigens Digestive tract Intestinal ade...noma SRX648718,SRX648717 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Dig.10.AllAg.Intestinal_adenoma.bed ...

  20. File list: InP.Dig.20.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Dig.20.AllAg.Intestines mm9 Input control Digestive tract Intestines ERX040294,...57,ERX040282,ERX040311,ERX040306,ERX040301,ERX040310,ERX040313,ERX040297,ERX040284 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Dig.20.AllAg.Intestines.bed ...

  1. File list: Pol.Dig.50.AllAg.Intestine,_Small [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Dig.50.AllAg.Intestine,_Small hg19 RNA polymerase Digestive tract Intestine, Sm...all http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Dig.50.AllAg.Intestine,_Small.bed ...

  2. File list: InP.Dig.50.AllAg.Intestinal_adenoma [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Dig.50.AllAg.Intestinal_adenoma mm9 Input control Digestive tract Intestinal ad...enoma http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Dig.50.AllAg.Intestinal_adenoma.bed ...

  3. File list: Oth.Dig.20.AllAg.Intestinal_stem_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.20.AllAg.Intestinal_stem_cells mm9 TFs and others Digestive tract Intestina...l stem cells SRX856961,SRX1141904,SRX1141903 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Dig.20.AllAg.Intestinal_stem_cells.bed ...

  4. File list: ALL.Dig.05.AllAg.Intestinal_villus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Dig.05.AllAg.Intestinal_villus mm9 All antigens Digestive tract Intestinal vill...SRX028556,SRX365695,SRX193725,SRX193724 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Dig.05.AllAg.Intestinal_villus.bed ...

  5. File list: NoD.Dig.50.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Dig.50.AllAg.Intestines mm9 No description Digestive tract Intestines ERX421319...,ERX421334,ERX421333,ERX421323,ERX421324,ERX421320,ERX421321,ERX421336,ERX421330 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/NoD.Dig.50.AllAg.Intestines.bed ...

  6. File list: ALL.Dig.10.AllAg.Intestinal_crypt [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Dig.10.AllAg.Intestinal_crypt mm9 All antigens Digestive tract Intestinal crypt... SRX871676,SRX871671,SRX871675,SRX871672 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Dig.10.AllAg.Intestinal_crypt.bed ...

  7. File list: Unc.Dig.50.AllAg.Intestinal_stem_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Dig.50.AllAg.Intestinal_stem_cells mm9 Unclassified Digestive tract Intestinal ...stem cells http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.Dig.50.AllAg.Intestinal_stem_cells.bed ...

  8. File list: Oth.Dig.50.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.50.AllAg.Intestines mm9 TFs and others Digestive tract Intestines SRX143801...,SRX1431656 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Dig.50.AllAg.Intestines.bed ...

  9. File list: Unc.Dig.20.AllAg.Intestinal_adenoma [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Dig.20.AllAg.Intestinal_adenoma mm9 Unclassified Digestive tract Intestinal ade...noma SRX648717 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.Dig.20.AllAg.Intestinal_adenoma.bed ...

  10. File list: Oth.Dig.05.AllAg.Intestinal_crypt [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.05.AllAg.Intestinal_crypt mm9 TFs and others Digestive tract Intestinal cry...pt SRX871676,SRX871675,SRX871671,SRX871672 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Dig.05.AllAg.Intestinal_crypt.bed ...

  11. File list: InP.Dig.10.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Dig.10.AllAg.Intestines mm9 Input control Digestive tract Intestines ERX040308,...9,ERX040286,ERX040293,ERX040301,SRX1431657,ERX040282,ERX040313,ERX040304,ERX040284 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Dig.10.AllAg.Intestines.bed ...

  12. File list: Oth.Dig.10.AllAg.Intestinal_stem_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.10.AllAg.Intestinal_stem_cells mm9 TFs and others Digestive tract Intestina...l stem cells SRX1141904,SRX856961,SRX1141903 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Dig.10.AllAg.Intestinal_stem_cells.bed ...

  13. File list: Pol.Dig.10.AllAg.Intestine,_Small [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Dig.10.AllAg.Intestine,_Small hg19 RNA polymerase Digestive tract Intestine, Sm...all http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Dig.10.AllAg.Intestine,_Small.bed ...

  14. File list: Pol.Dig.10.AllAg.Intestinal_crypt [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Dig.10.AllAg.Intestinal_crypt mm9 RNA polymerase Digestive tract Intestinal cry...pt http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Dig.10.AllAg.Intestinal_crypt.bed ...

  15. File list: ALL.Dig.20.AllAg.Intestine,_Small [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Dig.20.AllAg.Intestine,_Small mm9 All antigens Digestive tract Intestine, Small...1,SRX885794,SRX885795 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Dig.20.AllAg.Intestine,_Small.bed ...

  16. File list: DNS.Dig.20.AllAg.Intestinal_adenoma [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Dig.20.AllAg.Intestinal_adenoma mm9 DNase-seq Digestive tract Intestinal adenom...a http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.Dig.20.AllAg.Intestinal_adenoma.bed ...

  17. File list: Pol.Dig.20.AllAg.Intestine,_Small [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Dig.20.AllAg.Intestine,_Small hg19 RNA polymerase Digestive tract Intestine, Sm...all http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Dig.20.AllAg.Intestine,_Small.bed ...

  18. File list: NoD.Dig.20.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Dig.20.AllAg.Intestines mm9 No description Digestive tract Intestines ERX421334...,ERX421319,ERX421323,ERX421333,ERX421324,ERX421320,ERX421321,ERX421336,ERX421330 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/NoD.Dig.20.AllAg.Intestines.bed ...

  19. File list: Unc.Dig.20.AllAg.Intestine,_Small [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Dig.20.AllAg.Intestine,_Small hg19 Unclassified Digestive tract Intestine, Smal...l http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Dig.20.AllAg.Intestine,_Small.bed ...

  20. File list: ALL.Dig.50.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Dig.50.AllAg.Intestines mm9 All antigens Digestive tract Intestines SRX191044,S...040298,SRX341757,ERX040304,SRX185790,ERX040284,ERX040281,SRX112955,SRX185803 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Dig.50.AllAg.Intestines.bed ...

  1. File list: NoD.Dig.10.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Dig.10.AllAg.Intestines mm9 No description Digestive tract Intestines ERX421334...,ERX421319,ERX421333,ERX421323,ERX421324,ERX421320,ERX421321,ERX421336,ERX421330 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/NoD.Dig.10.AllAg.Intestines.bed ...

  2. File list: Unc.Dig.10.AllAg.Intestinal_villus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Dig.10.AllAg.Intestinal_villus mm9 Unclassified Digestive tract Intestinal vill...us SRX365695 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.Dig.10.AllAg.Intestinal_villus.bed ...

  3. File list: DNS.Dig.50.AllAg.Intestine,_Small [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Dig.50.AllAg.Intestine,_Small mm9 DNase-seq Digestive tract Intestine, Small ht...tp://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.Dig.50.AllAg.Intestine,_Small.bed ...

  4. File list: Oth.Dig.10.AllAg.Intestine,_Small [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.10.AllAg.Intestine,_Small hg19 TFs and others Digestive tract Intestine, Sm...all http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Dig.10.AllAg.Intestine,_Small.bed ...

  5. File list: Pol.Dig.20.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Dig.20.AllAg.Intestines mm9 RNA polymerase Digestive tract Intestines SRX112957...,SRX143802 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Dig.20.AllAg.Intestines.bed ...

  6. File list: InP.Dig.05.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Dig.05.AllAg.Intestines mm9 Input control Digestive tract Intestines ERX040294,...0,ERX040282,ERX040304,ERX040288,ERX040301,ERX040313,SRX1431657,ERX040293,ERX040284 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Dig.05.AllAg.Intestines.bed ...

  7. File list: Unc.Dig.05.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Dig.05.AllAg.Intestines mm9 Unclassified Digestive tract Intestines SRX112954,S...RX341757,SRX341758 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.Dig.05.AllAg.Intestines.bed ...

  8. File list: Oth.Dig.10.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Dig.10.AllAg.Intestines mm9 TFs and others Digestive tract Intestines SRX143801...,SRX1431656 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Dig.10.AllAg.Intestines.bed ...

  9. File list: Unc.Dig.10.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Dig.10.AllAg.Intestines mm9 Unclassified Digestive tract Intestines SRX112954,S...RX341757,SRX341758 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.Dig.10.AllAg.Intestines.bed ...

  10. File list: Unc.Dig.50.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Dig.50.AllAg.Intestines mm9 Unclassified Digestive tract Intestines SRX112954,S...RX341758,SRX341757 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.Dig.50.AllAg.Intestines.bed ...

  11. File list: ALL.Dig.05.AllAg.Intestinal_adenoma [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Dig.05.AllAg.Intestinal_adenoma mm9 All antigens Digestive tract Intestinal ade...noma SRX648718,SRX648717 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Dig.05.AllAg.Intestinal_adenoma.bed ...

  12. File list: NoD.Dig.20.AllAg.Intestinal_crypt [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Dig.20.AllAg.Intestinal_crypt mm9 No description Digestive tract Intestinal cry...pt http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/NoD.Dig.20.AllAg.Intestinal_crypt.bed ...

  13. File list: InP.Dig.10.AllAg.Intestine,_Small [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Dig.10.AllAg.Intestine,_Small hg19 Input control Digestive tract Intestine, Sma...ll http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.Dig.10.AllAg.Intestine,_Small.bed ...

  14. File list: ALL.Dig.20.AllAg.Intestinal_crypt [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Dig.20.AllAg.Intestinal_crypt mm9 All antigens Digestive tract Intestinal crypt... SRX871676,SRX871672,SRX871675,SRX871671 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Dig.20.AllAg.Intestinal_crypt.bed ...

  15. File list: Pol.Dig.05.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Dig.05.AllAg.Intestines mm9 RNA polymerase Digestive tract Intestines SRX112957...,SRX143802 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Dig.05.AllAg.Intestines.bed ...

  16. File list: ALL.Dig.10.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  17. File list: Oth.Dig.05.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  18. File list: Pol.Dig.50.AllAg.Intestinal_adenoma [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  19. File list: InP.Dig.05.AllAg.Colon_cancer [Chip-atlas[Archive

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  20. File list: Oth.Dig.05.TEAD4.AllCell [Chip-atlas[Archive

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  1. File list: InP.Dig.50.AllAg.Colon_cancer [Chip-atlas[Archive

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  2. File list: Unc.Dig.20.AllAg.Colon_cancer [Chip-atlas[Archive

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    Lifescience Database Archive (English)

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  4. File list: Oth.Dig.20.AllAg.Colon_cancer [Chip-atlas[Archive

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  5. File list: Oth.Dig.10.AllAg.Colon_cancer [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  6. File list: Oth.Dig.05.AllAg.Colon_cancer [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  7. File list: InP.Dig.10.AllAg.Colon_cancer [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  8. File list: Unc.Dig.50.AllAg.Colon_cancer [Chip-atlas[Archive

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  9. File list: Oth.Dig.50.AllAg.Colon_cancer [Chip-atlas[Archive

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  10. File list: Unc.Dig.10.AllAg.Colon_cancer [Chip-atlas[Archive

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  11. File list: Unc.Dig.05.AllAg.Colon_cancer [Chip-atlas[Archive

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  12. File list: DNS.Dig.10.AllAg.Intestine,_Small [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  13. File list: NoD.Dig.05.AllAg.Intestinal_crypt [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  14. File list: Pol.Dig.05.RNA_polymerase_II.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  15. File list: Pol.Dig.50.RNA_polymerase_III.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  16. File list: Pol.Dig.50.RNA_polymerase_II.AllCell [Chip-atlas[Archive

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  17. File list: Pol.Dig.10.RNA_polymerase_II.AllCell [Chip-atlas[Archive

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  18. File list: ALL.Dig.05.AllAg.Intestines [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  19. File list: Pol.Dig.50.AllAg.Intestines [Chip-atlas[Archive

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  20. File list: InP.Dig.10.Input_control.AllCell [Chip-atlas[Archive

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  1. File list: InP.Dig.50.Input_control.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  2. File list: InP.Dig.05.Input_control.AllCell [Chip-atlas[Archive

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  3. File list: InP.Dig.20.Input_control.AllCell [Chip-atlas[Archive

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  4. File list: InP.Dig.05.Input_control.AllCell [Chip-atlas[Archive

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  5. File list: InP.Dig.50.Input_control.AllCell [Chip-atlas[Archive

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  6. Project RAMA: Reconstructing Asteroids Into Mechanical Automata

    Science.gov (United States)

    Dunn, Jason; Fagin, Max; Snyder, Michael; Joyce, Eric

    2017-01-01

    Many interesting ideas have been conceived for building space-based infrastructure in cislunar space. From O'Neill's space colonies, to solar power satellite farms, and even prospecting retrieved near earth asteroids. In all the scenarios, one thing remained fixed - the need for space resources at the outpost. To satisfy this need, O'Neill suggested an electromagnetic railgun to deliver resources from the lunar surface, while NASA's Asteroid Redirect Mission called for a solar electric tug to deliver asteroid materials from interplanetary space. At Made In Space, we propose an entirely new concept. One which is scalable, cost effective, and ensures that the abundant material wealth of the inner solar system becomes readily available to humankind in a nearly automated fashion. We propose the RAMA architecture, which turns asteroids into self-contained spacecraft capable of moving themselves back to cislunar space. The RAMA architecture is just as capable of transporting conventional-sized asteroids on the 10-meter length scale as transporting asteroids 100 meters or larger, making it the most versatile asteroid retrieval architecture in terms of retrieved-mass capability. This report describes the results of the Phase I study funded by the NASA NIAC program for Made In Space to establish the concept feasibility of using space manufacturing to convert asteroids into autonomous, mechanical spacecraft. Project RAMA, Reconstituting Asteroids into Mechanical Automata, is designed to leverage the future advances of additive manufacturing (AM), in-situ resource utilization (ISRU) and in-situ manufacturing (ISM) to realize enormous efficiencies in repeated asteroid redirect missions. A team of engineers at Made In Space performed the study work with consultation from the asteroid mining industry, academia, and NASA. Previous studies for asteroid retrieval have been constrained to studying only asteroids that are both large enough to be discovered, and small enough to be

  7. Study of the Asteroid Florence

    Science.gov (United States)

    Vodniza, Alberto; Pereira, Mario

    2018-06-01

    Asteroid Florence was discovered at Siding Spring Observatory in Australia (March 1981). Paul Chodas, manager of CNEOS-JPL said: “Florence is the largest asteroid to pass by our planet this close since the NASA program to detect and track near-Earth asteroids began” [1]. The asteroid passed 7.1 million kilometers away from the earth [2]. The GDSCC-NASA discovered that the asteroid has two small moons. The diameter of Florence is 4.5 kilometers, and the sizes of the two moons are probably between 100 – 300 meters across. The inner moon has a rotation period around Florence of about 8 hours, and the outer moon has a period of about 25 hours [3]. From our Observatory, located in Pasto-Colombia, we captured several pictures, videos and astrometry data during several hours during three days. Our data was published by the Minor Planet Center (MPC) and also appears at the web page of NEODyS [4]. The pictures were captured with the following equipment: CGE PRO 1400 CELESTRON and STL-1001 SBIG camera. Astrometry and photometry was carried out, and we calculated the orbital elements and the rotation period. Summary and conclusions: We obtained the following orbital parameters: eccentricity = 0.422548 +/- 0.000994, semi-major axis = 1.76675 +/- 0.00313 A.U, orbital inclination = 22.128 +/- 0.029 deg, longitude of the ascending node = 336.0960 +/- 0.0013 deg, argument of perihelion = 27.861 +/- 0.016, mean motion = 0.41970 +/- 0.00112 deg/d, perihelion distance = 1.0202151 +/- 5.27e-5 A.U, aphelion distance = 2.51329 +/- 0.00625 A.U, absolute magnitude = 14.4. The parameters were calculated based on 281 observations. Dates: 2017 September 01 to 05 with mean residual = 0.19 arcseconds. The asteroid has an orbital period of 2.35 years (857.74 days). The rotation period of the asteroid is 2.3 hours. Note: Spaceweather published our video on September 1-2017 [5].[1] https://www.nasa.gov/feature/jpl/large-asteroid-to-safely-pass-earth-on-sept-1[2] http

  8. Volcanism on differentiated asteroids (Invited)

    Science.gov (United States)

    Wilson, L.

    2013-12-01

    The Dawn spacecraft's investigation of 4 Vesta, best-preserved of the early-forming differentiated asteroids, prompts a reappraisal of factors controlling igneous activity on such bodies. Analogy with melt transfer in zones of partial melting on Earth implies that silicate melts moved efficiently within asteroid mantles in complex networks of veins and dikes, so that only a few percent of the mantle consisted of melt at any one time. Thus even in cases where large amounts of mantle melting occurred, the melts did not remain in the mantle to form "magma oceans", but instead migrated to shallow depths. The link between magma flow rate and the stresses needed to keep fractures open and allow flow fast enough to avoid excessive cooling implies that only within asteroids with radii more than ~190-250 km would continuous magma flow from mantle to surface be possible. In all smaller asteroids (including Vesta) magma must have accumulated in sills at the base of the lithosphere (the conductively controlled ~10 km thick thermal boundary layer) or in crustal magma reservoirs near its base. Magma would then have erupted intermittently to the surface from these steadily replenished reservoirs. The average rates of eruption to the surface (or shallow intrusion) should balance the magma production rate, but since magma could accumulate and erupt intermittently from these reservoirs, the instantaneous eruption rates could be hundreds to thousands of cubic m/s, comparable to historic basaltic eruption rates on Earth and very much greater than the average mantle melting rate. The absence of asteroid atmospheres makes explosive eruptions likely even if magmas are volatile-poor. On asteroids with radii less than ~100 km, gases and sub-mm pyroclastic melt droplets would have had speeds exceeding the escape speed assuming a few hundred ppm volatiles, and only cm sized or larger clasts would have been retained. On larger bodies almost all pyroclasts will have returned to the surface

  9. Spectral Classification of Asteroids by Random Forest

    Science.gov (United States)

    Huang, Chao; Ma, Yue-hua; Zhao, Hai-bin; Lu, Xiao-ping

    2017-10-01

    With the increasing spectral and photometric data of asteroids, a variety of classification methods for asteroids have been proposed. This paper classifies asteroids based on the observations in the Sloan Digital Sky Survey (SDSS) Moving Object Catalogue (MOC) by using the random forest algorithm. In combination with the present taxonomies of Tholen, Bus, Lazzaro, and DeMeo, and the principal component analysis, we have classified 48642 asteroids according to their SDSS magnitudes at the g, r, i, and z wavebands. In this way, these asteroids are divided into 8 (C, X, S, B, D, K, L, and V) classes.

  10. Spectral Classification of Asteroids by Random Forest

    Science.gov (United States)

    Huang, C.; Ma, Y. H.; Zhao, H. B.; Lu, X. P.

    2016-09-01

    With the increasing asteroid spectral and photometric data, a variety of classification methods for asteroids have been proposed. This paper classifies asteroids based on the observations of Sloan Digital Sky Survey (SDSS) Moving Object Catalogue (MOC) by using the random forest algorithm. With the training data derived from the taxonomies of Tholen, Bus, Lazzaro, DeMeo, and Principal Component Analysis, we classify 48642 asteroids according to g, r, i, and z SDSS magnitudes. In this way, asteroids are divided into 8 spectral classes (C, X, S, B, D, K, L, and V).

  11. Simultaneous Mass Determination for Gravitationally Coupled Asteroids

    Energy Technology Data Exchange (ETDEWEB)

    Baer, James [Private address, 3210 Apache Road, Pittsburgh, PA 15241 (United States); Chesley, Steven R., E-mail: jimbaer1@earthlink.net [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

    2017-08-01

    The conventional least-squares asteroid mass determination algorithm allows us to solve for the mass of a large subject asteroid that is perturbing the trajectory of a smaller test asteroid. However, this algorithm is necessarily a first approximation, ignoring the possibility that the subject asteroid may itself be perturbed by the test asteroid, or that the encounter’s precise geometry may be entangled with encounters involving other asteroids. After reviewing the conventional algorithm, we use it to calculate the masses of 30 main-belt asteroids. Compared to our previous results, we find new mass estimates for eight asteroids (11 Parthenope, 27 Euterpe, 51 Neimausa, 76 Freia, 121 Hermione, 324 Bamberga, 476 Hedwig, and 532 Herculina) and significantly more precise estimates for six others (2 Pallas, 3 Juno, 4 Vesta, 9 Metis, 16 Psyche, and 88 Thisbe). However, we also find that the conventional algorithm yields questionable results in several gravitationally coupled cases. To address such cases, we describe a new algorithm that allows the epoch state vectors of the subject asteroids to be included as solve-for parameters, allowing for the simultaneous solution of the masses and epoch state vectors of multiple subject and test asteroids. We then apply this algorithm to the same 30 main-belt asteroids and conclude that mass determinations resulting from current and future high-precision astrometric sources (such as Gaia ) should conduct a thorough search for possible gravitational couplings and account for their effects.

  12. Simultaneous Mass Determination for Gravitationally Coupled Asteroids

    Science.gov (United States)

    Baer, James; Chesley, Steven R.

    2017-08-01

    The conventional least-squares asteroid mass determination algorithm allows us to solve for the mass of a large subject asteroid that is perturbing the trajectory of a smaller test asteroid. However, this algorithm is necessarily a first approximation, ignoring the possibility that the subject asteroid may itself be perturbed by the test asteroid, or that the encounter’s precise geometry may be entangled with encounters involving other asteroids. After reviewing the conventional algorithm, we use it to calculate the masses of 30 main-belt asteroids. Compared to our previous results, we find new mass estimates for eight asteroids (11 Parthenope, 27 Euterpe, 51 Neimausa, 76 Freia, 121 Hermione, 324 Bamberga, 476 Hedwig, and 532 Herculina) and significantly more precise estimates for six others (2 Pallas, 3 Juno, 4 Vesta, 9 Metis, 16 Psyche, and 88 Thisbe). However, we also find that the conventional algorithm yields questionable results in several gravitationally coupled cases. To address such cases, we describe a new algorithm that allows the epoch state vectors of the subject asteroids to be included as solve-for parameters, allowing for the simultaneous solution of the masses and epoch state vectors of multiple subject and test asteroids. We then apply this algorithm to the same 30 main-belt asteroids and conclude that mass determinations resulting from current and future high-precision astrometric sources (such as Gaia) should conduct a thorough search for possible gravitational couplings and account for their effects.

  13. Simultaneous Mass Determination for Gravitationally Coupled Asteroids

    International Nuclear Information System (INIS)

    Baer, James; Chesley, Steven R.

    2017-01-01

    The conventional least-squares asteroid mass determination algorithm allows us to solve for the mass of a large subject asteroid that is perturbing the trajectory of a smaller test asteroid. However, this algorithm is necessarily a first approximation, ignoring the possibility that the subject asteroid may itself be perturbed by the test asteroid, or that the encounter’s precise geometry may be entangled with encounters involving other asteroids. After reviewing the conventional algorithm, we use it to calculate the masses of 30 main-belt asteroids. Compared to our previous results, we find new mass estimates for eight asteroids (11 Parthenope, 27 Euterpe, 51 Neimausa, 76 Freia, 121 Hermione, 324 Bamberga, 476 Hedwig, and 532 Herculina) and significantly more precise estimates for six others (2 Pallas, 3 Juno, 4 Vesta, 9 Metis, 16 Psyche, and 88 Thisbe). However, we also find that the conventional algorithm yields questionable results in several gravitationally coupled cases. To address such cases, we describe a new algorithm that allows the epoch state vectors of the subject asteroids to be included as solve-for parameters, allowing for the simultaneous solution of the masses and epoch state vectors of multiple subject and test asteroids. We then apply this algorithm to the same 30 main-belt asteroids and conclude that mass determinations resulting from current and future high-precision astrometric sources (such as Gaia ) should conduct a thorough search for possible gravitational couplings and account for their effects.

  14. The Steward Observatory asteroid relational database

    Science.gov (United States)

    Sykes, Mark V.; Alvarezdelcastillo, Elizabeth M.

    1991-01-01

    The Steward Observatory Asteroid Relational Database (SOARD) was created as a flexible tool for undertaking studies of asteroid populations and sub-populations, to probe the biases intrinsic to asteroid databases, to ascertain the completeness of data pertaining to specific problems, to aid in the development of observational programs, and to develop pedagogical materials. To date, SOARD has compiled an extensive list of data available on asteroids and made it accessible through a single menu-driven database program. Users may obtain tailored lists of asteroid properties for any subset of asteroids or output files which are suitable for plotting spectral data on individual asteroids. The program has online help as well as user and programmer documentation manuals. The SOARD already has provided data to fulfill requests by members of the astronomical community. The SOARD continues to grow as data is added to the database and new features are added to the program.

  15. Shape and spin of asteroid 967 Helionape

    Science.gov (United States)

    Apostolovska, G.; Kostov, A.; Donchev, Z.; Bebekovska, E. Vchkova; Kuzmanovska, O.

    2018-04-01

    Knowledge of the spin and shape parameters of the asteroids is very important for understanding of the conditions during the creation of our planetary system and formation of asteroid populations. The main belt asteroid and Flora family member 967 Helionape was observed during five apparitions. The observations were made at the Bulgarian National Astronomical Observatory (BNAO) Rozhen, since March 2006 to March 2016. Lihtcurve inversion method (Kaasalainen et al. (2001)), applied on 12 relative lightcurves obtained at various geometric conditions of the asteroid, reveals the spin vector, the sense of rotation and the preliminary shape model of the asteroid. Our aim is to contribute in increasing the set of asteroids with known spin and shape parameters. This could be done with dense lightcurves, obtained during small number of apparitions, in combination with sparse data produced by photometric asteroid surveys such as the Gaia satellite (Hanush (2011)).

  16. The Asteroid Redirect Mission (ARM)

    Science.gov (United States)

    Abell, Paul; Gates, Michele; Johnson, Lindley; Chodas, Paul; Mazanek, Dan; Reeves, David; Ticker, Ronald

    2016-07-01

    To achieve its long-term goal of sending humans to Mars, the National Aeronautics and Space Administration (NASA) plans to proceed in a series of incrementally more complex human spaceflight missions. Today, human flight experience extends only to Low-Earth Orbit (LEO), and should problems arise during a mission, the crew can return to Earth in a matter of minutes to hours. The next logical step for human spaceflight is to gain flight experience in the vicinity of the Moon. These cis-lunar missions provide a "proving ground" for the testing of systems and operations while still accommodating an emergency return path to the Earth that would last only several days. Cis-lunar mission experience will be essential for more ambitious human missions beyond the Earth-Moon system, which will require weeks, months, or even years of transit time. In addition, NASA has been given a Grand Challenge to find all asteroid threats to human populations and know what to do about them. Obtaining knowledge of asteroid physical properties combined with performing technology demonstrations for planetary defense provide much needed information to address the issue of future asteroid impacts on Earth. Hence the combined objectives of human exploration and planetary defense give a rationale for the Asteroid Re-direct Mission (ARM). Mission Description: NASA's ARM consists of two mission segments: 1) the Asteroid Redirect Robotic Mission (ARRM), the first robotic mission to visit a large (greater than ~100 m diameter) near-Earth asteroid (NEA), collect a multi-ton boulder from its surface along with regolith samples, demonstrate a planetary defense technique, and return the asteroidal material to a stable orbit around the Moon; and 2) the Asteroid Redirect Crewed Mission (ARCM), in which astronauts will take the Orion capsule to rendezvous and dock with the robotic vehicle, conduct multiple extravehicular activities to explore the boulder, and return to Earth with samples. NASA's proposed

  17. Soils

    Science.gov (United States)

    Emily Moghaddas; Ken Hubbert

    2014-01-01

    When managing for resilient forests, each soil’s inherent capacity to resist and recover from changes in soil function should be evaluated relative to the anticipated extent and duration of soil disturbance. Application of several key principles will help ensure healthy, resilient soils: (1) minimize physical disturbance using guidelines tailored to specific soil types...

  18. A Study of Digging Productivity of an Electric Rope Shovel for Different Operators

    Directory of Open Access Journals (Sweden)

    Mohammad Babaei Khorzoughi

    2016-05-01

    Full Text Available A performance monitoring study of an electric rope shovel operating in an open pit coal mine was conducted. As the mining industry moves toward higher productivity, profitability and predictability, the need for more reliable, productive and efficient mining shovels increases. Consequently, it is critical to study the productivity of these machines and to understand the effect of different operational parameters on that. In this paper a clustering analysis is performed to classify shovel digging effort and behaviour based on digging energy, dig time and payload per pass. Then the influence of the operator on the digging efficiency and productivity of the machine is analyzed with a focus on operator technique during digging. A statistical analysis is conducted on different cycle time components (dig time, swing time, return time for different operators. In addition to time components, swing and return angles as well as loading rate and mucking rate are observed and analyzed. The results of this study help to understand the effect of different operators on the digging productivity of the shovel and then to set the best operator practice.

  19. Photometry of faint asteroids and satellites

    International Nuclear Information System (INIS)

    Degewij, J.

    1978-01-01

    The smaller asteroids, having diameters of about 1 km, appear to rotate faster than do the larger asteroids (approximately 200 km diameter). Most of the bodies may be nearly spherical, probably due to a collisional erosion process in the Main Belt of asteroids. The distributions of diameter versus number were studied for low albedo (C, for carbonaceous) and high albedo (S, for silicaceous) type asteroids in the main belt, down to diameters of 25 km. Among the smaller bodies the S type asteroids are relatively more abundant, probably due to greater crushing strength for S type asteroids. This indicates that both optical types have also different properties in the interior of the body. Areas with slightly different reflectivity over the surface of an asteroid were detected; the rotational light variation of asteroid 4 (Vesta) was found to be caused by spots on its surface. Colorimetry and infrared radiometry of some Hilda asteroids, Trojans and the fainter satellites of Jupiter and Saturn, all having diameters between 100 and 200 km, show that a mixture of types exist. If some asteroids are nearly expended nuclei of comets that lost most of their volatile gaseous material, then their cometary activity is expected to be extinct or at least weak. (Auth.)

  20. Asteroids. Prospective energy and material resources

    Energy Technology Data Exchange (ETDEWEB)

    Badescu, Viorel (ed.) [Bucharest Polytechnic Univ. (Romania). Candida Oancea Institute

    2013-11-01

    Recent research on Prospective Energy and Material Resources on Asteroids. Carefully edited book dedicated to Asteroids prospective energy and material resources. Written by leading experts in the field. The Earth has limited material and energy resources while these resources in space are virtually unlimited. Further development of humanity will require going beyond our planet and exploring of extraterrestrial resources and sources of unlimited power. Thus far, all missions to asteroids have been motivated by scientific exploration. However, given recent advancements in various space technologies, mining asteroids for resources is becoming ever more feasible. A significant portion of asteroids value is derived from their location; the required resources do not need to be lifted at a great expense from the surface of the Earth. Resources derived from Asteroid not only can be brought back to Earth but could also be used to sustain human exploration of space and permanent settlements in space. This book investigates asteroids' prospective energy and material resources. It is a collection of topics related to asteroid exploration, and utilization. It presents past and future technologies and solutions to old problems that could become reality in our life time. The book therefore is a great source of condensed information for specialists involved in current and impending asteroid-related activities and a good starting point for space researchers, inventors, technologists and potential investors. Written for researchers, engineers, and businessmen interested in asteroids' exploration and exploitation.

  1. Asteroid exploration and utilization: The Hawking explorer

    Science.gov (United States)

    Carlson, Alan; Date, Medha; Duarte, Manny; Erian, Neil; Gafka, George; Kappler, Peter; Patano, Scott; Perez, Martin; Ponce, Edgar; Radovich, Brian

    1991-01-01

    The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources which may exist on asteroids could have enormous potential for aiding and enhancing human space exploration as well as life on Earth. With the possibly limitless opportunities that exist, it is clear that asteroids are the next step for human existence in space. This report comprises the efforts of NEW WORLDS, Inc. to develop a comprehensive design for an asteroid exploration/sample return mission. This mission is a precursor to proof-of-concept missions that will investigate the validity of mining and materials processing on an asteroid. Project STONER (Systematic Transfer of Near Earth Resources) is based on two utilization scenarios: (1) moving an asteroid to an advantageous location for use by Earth; and (2) mining an asteroids and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the context of both scenarios and is the first phase of a long range plane for humans to utilize asteroid resources. The report concentrates specifically on the selection of the most promising asteroids for exploration and the development of an exploration scenario. Future utilization as well as subsystem requirements of an asteroid sample return probe are also addressed.

  2. Colorimetry and magnitudes of asteroids

    Science.gov (United States)

    Bowell, E.; Lumme, K.

    1979-01-01

    In the present paper, 1500 UBV observations are analyzed by a new rather general multiple scattering theory which provided clear insight into previously poorly-recognized optical nature of asteroid surfaces. Thus, phase curves are shown to consist of a surface-texture controlled component, due to singly scattered light, and a component due to multiple scattering. Phase curve shapes can be characterized by a single parameter, the multiple scattering factor, Q. As Q increases, the relative importance of the opposition effect diminishes. Asteroid surfaces are particulate and strikingly similar to texture, being moderately porous and moderately rough on a scale greater than the wavelength of light. In concequence, Q (and also the phase coefficient) correlate well with geometric albedo, and there exists a purely photometric means of determining albedos and diameters.

  3. The asteroid 2014 JO25

    Science.gov (United States)

    Vodniza, Alberto; Pereira, Mario

    2017-10-01

    The asteroid 2014 JO25 was discovered by A. D. Grauer at the Mt. Lemmon Survey on May 2014, and Joe Masiero used observations from the NEOWISE in 2014 to estimate a diameter of 650 meters [1]. However, using the radio telescope at Arecibo-Puerto Rico, astronomers obtained radar images on April 17-2017 and Edgar Rivera Valentín (scientist at Arecibo) said: “We found 2014 JO25 is a contact binary asteroid, two space rocks that were originally separate bodies, and each segment is about 640 meters and 670 meters, for a total of about 1.3 km long. Its rotation is of 3.5 hours” [2]. This asteroid flew past Earth on April 19 at a distance of about 4.6 lunar distances from the Earth. This was the closest approach by an asteroid since 4179 Toutatis. Toutatis flew past Earth on September 2004 at a distance of about 4 lunar distances from the Earth [3]. In April 12-2020 the asteroid will be at a minimum possible distance of 0.1617280 A.U from Earth [4]. From our observatory, located in Pasto-Colombia, we obtained a lot of pictures. Our data was published by the Minor Planet Center [5] and also appears at the web page of NEODyS [6]. Astrometry and photometry were carried out, and we calculated the orbital elements. We obtained the following orbital parameters: eccentricity=0.88454+/-0.00152, semi-major axis= 2.0573+/- 0.0216 A.U, orbital inclination=25.22+/-0.10 deg, longitude of the ascending node =30.6530+/-0.0032 deg, argument of perihelion=49.586+/-0.012 deg, mean motion = 0.33402+/-0.00527 deg/d, perihelion distance=0.237524+/-0.000644 A.U, aphelion distance=3.8770+/-0.0449 A.U, absolute magnitude =18.1. The parameters were calculated based on 164 observations. Dates: 2017 April: 22 to 24 with mean residual=0.22 arcseconds.The asteroid has an orbital period of 2.95 years.[1] https://echo.jpl.nasa.gov/asteroids/2014JO25/2014JO25_planning.html[2] http://earthsky.org/astronomy-essentials/large-asteroid-2014-jo25-close-april-19-2017-how-to-see[3] https

  4. Looking into the evolution of granular asteroids in the Solar System

    Science.gov (United States)

    Sánchez, Paul; Scheeres, Daniel; Hirabayashi, Masatoshi; Tardivel, Simon

    2017-06-01

    By now it has been accepted that most of the small asteroids in the Solar System are granular aggregates kept together by gravitational and possibly, cohesive forces. These aggregates can form, deform and disrupt over millennia subjected to different internal and external factors that would ultimately determine how they evolve over time. Parameters such as porosity, cohesive and tensile strength, angles of friction, particle size distributions, stress states, heterogeneity and yield criteria among others, determine how these granular systems will react when subjected to different, changing, external factors. These external factors include solar photon momentum, gravitational tides, micro- and macro-impacts and are believed to have produced and shaped the current asteroid population. In our research we use a combination of Soil Mechanics theory, Soft-Sphere Discrete Element Method (SSDEM) Simulations and Orbital Mechanics in order to understand how simulated, homogeneous and heterogeneous, ellipsoidal and spherical gravitational aggregates, a crude but useful representation of an asteroid, evolve when rotated to the point of disruption. Then, we compare our results to the shapes of observed asteroids as well as to the disruption patterns of a few active asteroids. Our results lead us to believe that the different shapes of observed asteroids as well as their unique disruption patterns could give us clues about their internal structure, strength and geophysical properties in general.

  5. Asteroids prospective energy and material resources

    CERN Document Server

    2013-01-01

    The Earth has limited material and energy resources while these resources in space are virtually unlimited. Further development of humanity will require going beyond our planet and exploring of extraterrestrial resources and sources of unlimited power.   Thus far, all missions to asteroids have been motivated by scientific exploration. However, given recent advancements in various space technologies, mining asteroids for resources is becoming ever more feasible. A significant portion of asteroids value is derived from their location; the required resources do not need to be lifted at a great expense from the surface of the Earth.   Resources derived from Asteroid not only can be brought back to Earth but could also be used to sustain human exploration of space and permanent settlements in space.   This book investigates asteroids' prospective energy and material resources. It is a collection of topics related to asteroid exploration, and utilization. It presents past and future technologies and solutions t...

  6. Physical studies of asteroids. XXXII. Rotation periods and UBVRI-colours for selected asteroids

    Science.gov (United States)

    Piironen, J.; Lagerkvist, C.-I.; Erikson, A.; Oja, T.; Magnusson, P.; Festin, L.; Nathues, A.; Gaul, M.; Velichko, F.

    1998-03-01

    We present lightcurves of selected asteroids. Most of the asteroids were included to obtain refined spin periods. Enhanced periods were determined for 11 Parthenope, 306 Unitas and 372 Palma. We confirmed the spin periods of 8 Flora, 13 Egeria, 71 Niobe, 233 Asterope, 291 Alice, 409 Aspasia, 435 Ella and 512 Taurinensis. We determined also BV-colours for most of the included asteroids and UBVRI-colours for a total of 22 asteroids.

  7. Asteroid families, dynamics and astrometry

    International Nuclear Information System (INIS)

    Williams, J.G.; Gibson, J.

    1987-01-01

    The proper elements and family assignments for the 1227 Palomar-Leiden Survey asteroids of high quality were tabulated. In addition to the large table, there are also auxiliary tables of Mars crossers and commensurate objects, histograms of the proper element distributions, and a discussion. Probably the most important part of the discussion describes the Mars crossing boundary, how the closest distances of approach to Mars and Jupiter are calculated, and why the observed population of Mars crossers should bombard that planet episodically rather than uniformly. Analytical work was done to derive velocity distributions of family forming events from proper element distributions subject to assumptions which may be appropriate for cratering events. Software was developed for a microcomputer to permit plotting of the proper elements. Three orthogonal views are generated and stereo pairs can be printed when desired. This program was created for the study of asteroid families. The astrometry task is directed toward measuring and reducing positions on faint comets and the minor planets with less common orbits. The observational material is CCD frames taken with the Palomar 1.5 m telescope. Positions of 10 comets and 16 different asteroids were published on the Minor Planet Circulars

  8. Storyboard GALILEO CRUISE SCIENCE OPPORTUNITIES describes asteroid encounters

    Science.gov (United States)

    1989-01-01

    Storyboard with mosaicked image of an asteroid and entitled GALILEO CRUISE SCIENCE OPPORTUNITIES describes asteroid objectives. These objectives include: first asteroid encounter; surface geology, composition size, shape, mass; and relation of primitive bodies to meteorites.

  9. Update on an Interstellar Asteroid

    Science.gov (United States)

    Kohler, Susanna

    2018-01-01

    Whats the news coming from the research world on the interstellar asteroid visitor, asteroid 1I/Oumuamua? Read on for an update from a few of the latest studies.What is Oumuamua?In lateOctober2017, the discovery of minor planet 1I/Oumuamua was announced. This body which researchers first labeled asa comet and later revised to an asteroid had just zipped around the Sun and was already in the process of speeding away whenwe trained our telescopes on it. Its trajectory, however, marked it as being a visitor from outside our solar system: the first knownvisitorof its kind.Since Oumuamuasdiscovery, scientists have been gathering as many observations of this bodyas possible before it vanishes into the distance. Simultaneously, theorists have leapt at the opportunity to explain its presence and the implications its passage has on our understanding of our surroundings. Here we present just a few of the latest studies that have been published on this first detected interstellar asteroid including several timelystudies published in our new journal, Research Notes of the AAS.The galactic velocity of Oumuamua does not coincide with any of the nearest stars to us. [Mamajek 2018]Where Did Oumuamua Come From?Are we sure Oumuamua didnt originate in our solar system andget scattered into a weird orbit? Jason Wright (The Pennsylvania State University) demonstrates via a series of calculations that no known solar system body could have scattered Oumuamua onto its current orbit nor could any stillunknown object bound to our solar system.Eric Mamajek (Caltech and University of Rochester) showsthat thekinematics of Oumuamua areconsistent with what we might expect of interstellar field objects, though he argues that its kinematics suggest its unlikely to have originated from many of the neareststellar systems.What AreOumuamuas Properties?Oumuamuas light curve. [Bannister et al. 2017]A team of University of Maryland scientists led by Matthew Knight captured a light curve of Oumuamua using

  10. Effect of the presence of brood and fungus on the nest architecture and digging activity of Acromyrmex subterraneus Forel (Hymenoptera, Formicidae

    Directory of Open Access Journals (Sweden)

    Carlos Magno dos Santos

    Full Text Available ABSTRACT This study investigated the stimuli that trigger digging behavior in Acromyrmex subterraneus during nest building. The hypothesis was that the presence of the fungus garden and/or brood triggers the excavation of tunnels and chambers. For the experiment, the excavation rate of individually marked workers kept in plastic cylinders filled with soil was recorded. Four treatments were applied: (1 30 medium-sized workers, 5 g fungus garden and 30 brood items (larvae and pupae; (2 30 medium-sized workers and 5 g fungus garden; (3 30 medium-sized workers and 30 brood items; (4 30 medium-sized workers without fungus and brood. After 24 h, morphological parameters of nest structure (length and width of the chambers and tunnels in cm and the volume of excavated soil were recorded. In contrast to the expected findings, no change in morphological structure, rate of excavation by workers, or volume of excavated soil was observed between treatments, except for tunnel width, which was greater, when no brood or fungus garden was present. Thus, the results do not support the hypothesis that the fungus garden and/or brood are local stimuli for nest excavation or that they mold the internal architecture of the nest. Although this hypothesis was confirmed for Acromyrmex lundii and Atta sexdens rubropilosa, the same does not apply to A. subterraneus. The digging behavior of workers is probably the result of adaptation during nest building in different habitats.

  11. Asteroid size distributions for the main belt and for asteroid families

    Science.gov (United States)

    Kazantzev, A.; Kazantzeva, L.

    2017-12-01

    The asteroid-size distribution for he Eos family was constructed. The WISE database containing the albedo p and the size D of over 80,000 asteroids was used. The b parameter of the power-law dependence has a minimum at some average values of the asteroid size of the family. A similar dependence b(D) exists for the whole asteroid belt. An assumption on the possible similarity of the formation mechanisms of the asteroid belt as a whole and separate families is made.

  12. Digging in one last time for the LHC

    CERN Multimedia

    2003-01-01

    A landmark event occurred during the second week of March, when the final cubic metres of earth were cleared away, completing the excavation phase for the entire LHC project . The event took place at Point 5, where the CMS detector will be installed, as civil engineering teams finished digging the cavern that connects the LHC tunnel with the bypass tunnel around the experimental cavern. Two new access shafts, two large caverns, two ancillary caverns, as well as the connecting tunnels have been excavated by the civil engineering teams. "The engineers heaved a huge sigh of relief when the work was done, because the excavations were quite risky. Anything can happen, and the risk of delays was far from zero," explains Jean Luc Baldy Head of ST Division's civil engineering group. This was especially true around Point 5, where unusual geology created some problems. The moraine-molasse interface lies 50 metres beneath the surface, or just about 18 metres above the roof of the caverns. Because the moraine consists of...

  13. Asteroid Impact & Deflection Assessment mission: Kinetic impactor

    Czech Academy of Sciences Publication Activity Database

    Cheng, A.F.; Michel, R.; Jutzi, M.; Rivkin, A. S.; Stickle, A.; Barnouin, O.; Ernst, C.; Atchison, J.; Pravec, Petr; Richardson, D.C.

    2016-01-01

    Roč. 121, February (2016), s. 25-37 ISSN 0032-0633 Institutional support: RVO:67985815 Keywords : planetary defense * near- Earth asteroids * asteroid impact hazards Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 1.892, year: 2016

  14. Binary asteroid population. 1. Angular momentum content

    Czech Academy of Sciences Publication Activity Database

    Pravec, Petr; Harris, A. W.

    2007-01-01

    Roč. 190, č. 1 (2007), s. 250-259 ISSN 0019-1035 R&D Projects: GA ČR(CZ) GA205/05/0604 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroids * satellites of asteroids Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.869, year: 2007

  15. Spectroscopy of near-Earth asteroids

    DEFF Research Database (Denmark)

    Michelsen, René; Nathues, Andreas; Lagerkvist, Claes-Ingvar

    2006-01-01

    We present spectra and taxonomic classifications of 12 Near-Earth Asteroids (NEAs) and 2 inner Main Belt asteroids. The observations were carried out with the ESO 3.5 m NTT and the Danish 1.54 m telescope at La Silla, Chile. Eleven of the investigated NEAs belong to the S class while only one C-t...

  16. Cohesion of Mm- to Cm-Sized Asteroid Simulant Grains: An Experimental Study

    Science.gov (United States)

    Brisset, Julie; Colwell, Joshua E.; Dove, Adrienne; Jarmak, Stephanie; Anderson, Seamus

    2017-10-01

    The regolith covering the surfaces of asteroids and planetary satellites is very different from terrestrial soil particles and subject to environmental conditions very different from what is found on Earth. The loose, unconsolidated granular material has angular-shaped grains and a broad size distribution. On small and airless bodies (Earth surface gravity, the cohesion behavior of the regolith grains will dictate the asteroid’s surface morphology and its response to impact or spacecraft contact.Previous laboratory experiments on low-velocity impacts into regolith simulant with grain sizes landing missions to small bodies such as asteroids or Martian moons.

  17. Lightcurve Photometry of Six Asteroids

    Science.gov (United States)

    Ferrero, Andrea

    2012-07-01

    Observations from 2012 January to March lead to the determination of the rotation periods for six main-belt asteroids: 33 Polyhymnia, P = 18.604 ± 0.004 h; 467 Laura, P = 37.4 ± 0.1 h; 825 Tanina, P = 6.940 ± 0.001 h; 1421 Esperanto, P = 21.982 ± 0.005 h; 3481 Xianglupeak, P = 5.137 ± 0.003 h; and 4350 Shibecha, which had two possible solutions, P = 2.890 ± 0.001 h and P = 5.778 ± 0.002 h.

  18. Absence of satellites of asteroids

    International Nuclear Information System (INIS)

    Gehrels, T.; Drummond, J.D.; Levenson, N.A.

    1987-01-01

    The absence of satellites within 0.1-7.0 arcmin of minor planets noted in the present CCD imaging survey is judged consistent with previous theoretical studies of collisions in which it is held that satellites would have to be larger than about 30 km in order to be collisionally stable. In view of tidal stability, the only main belt asteroid satellites which could conceivably possess stability over eons are near-contact binaries. Any recent collisional debris would be chaotic and collisionally unstable. 15 references

  19. UV Spectroscopy of Metallic Asteroid (16) Psyche

    Science.gov (United States)

    Cunningham, N. J.; Becker, T. M.; Retherford, K. D.; Roth, L.; Feaga, L. M.; Wahlund, J.-E.; Elkins-Tanton, L. T.

    2017-09-01

    Asteroid (16) Psyche is the largest M-type asteroid, and the planned destination of the NASA Discovery mission Psyche and the proposed ESA M5 mission Heavy Metal. Psyche is considered to be the exposed core of a differentiated asteroid, whose mantle has been stripped by collisions; but other histories have been proposed. We observed Psyche with the Space Telescope Imaging Spectrograph (STIS) and Cosmic Origins Spectrograph (COS) aboard the Hubble Space Telescope, to obtain a full ultraviolet (UV) spectrum of both of Psyche's hemispheres. We seek to test three possible scenarios for Psyche's origin: Is Psyche the exposed core of a differentiated asteroid? Is it an asteroid with high olivine content that has been space-weathered? Or did Psyche accrete as-is in a highly-reducing environment early in the history of the solar system? We will present the UV spectra and their implications for Psyche's history.

  20. Treatment of peat bogs harvested by deep digging technique

    International Nuclear Information System (INIS)

    Hoernsten, L.

    1992-06-01

    The aim of this study is to describe how peat bogs harvested by deep digging technique can be treated after harvesting has come to an end. The study points out treatment methods, how the treatments are carried out and to indicate the most appropriate method of harvest for optimum results. Costs and benefits are calculated for the methods involving cultivation. The knowledge gained from traditional peat harvesting technique indicate forestry, energy wood production and establishment of ponds as possible alternatives. Energy grass cultivation and establishments of game parks have not been tested. but are assumed to be viable on suitable sites. Establishment of duck ponds are also possible, even though conditions for these are better on firm ground. In this study spruce is estimated to produce 200 cubic meters during 105 year whilst pine produces 300 cubic meters. Calculations for pine and spruce estimate costs of respectively 17000 and 18000 SEK per hectare after 105 years. Energy wood production is estimated to be 11.6 tons dry matter per hectare and year which gives a net cost of 19000 SEK per hectare. Similarly energy grass cultivation results in an average annual harvest of 6.5 ton dry matter and a cost of 59000 SEK per hectare. If the results are applied to three specific cases, then forest cultivation and establishment of ponds are possible in all cases. Neither energy wood nor energy grass are appropriate in any of the three regions. At the particular site for this study all methods mentioned are possible. Depending on whether draining leads to a high or low water table, the most appropriate course would be the establishment of a pond respectively a game park of forest cultivation. (59 refs., 12 tabs., 4 figs.)

  1. Soil

    International Nuclear Information System (INIS)

    Freudenschuss, A.; Huber, S.; Riss, A.; Schwarz, S.; Tulipan, M.

    2002-01-01

    Environmental soil surveys in each province of Austria have been performed, soils of about 5,000 sites were described and analyzed for nutrients and pollutants, the majority of these data are recorded in the soil information system of Austria (BORIS) soil database, http://www.ubavie.gv.at/umweltsituation/boden/boris), which also contains a soil map of Austria, data from 30 specific investigations mainly in areas with industry and results from the Austria - wide cesium investigation. With respect to the environmental state of soils a short discussion is given, including two geographical charts, one showing which sites have soil data (2001) and the other the cadmium distribution in top soils according land use (forest, grassland, arable land, others). Information related to the soil erosion, Corine land cover (Europe-wide land cover database), evaluation of pollutants in soils (reference values of As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Se, Pb, Tl, Va, Zn, AOX, PAH, PCB, PCDD/pcdf, dioxin), and relevant Austrian and European standards and regulations is provided. Figs. 2, Tables 4. (nevyjel)

  2. Working Group Reports and Presentations: Asteroids

    Science.gov (United States)

    Lewis, John

    2006-01-01

    The study and utilization of asteroids will be an economical way to enable exploration of the solar system and extend human presence in space. There are thousands of near-earth objects (NEOs) that we will be able to reach. They offer resources, transportation, and exploration platforms, but also present a potential threat to civilization. Asteroids play a catastrophic role in the history of the Earth. Geological records indicate a regular history of massive impacts, which astronomical observations confirm is likely to continue with potentially devastating consequences. However, study and exploration of near earth asteroids can significantly increase advanced warning of an Earth impact, and potentially lead to the technology necessary to avert such a collision. Efforts to detect and prevent cataclysmic events would tend to foster and likely require international cooperation toward a unified goal of self-preservation. Exploration of asteroids will help us to understand our history and perhaps save our future. Besides the obvious and compelling scientific and security drivers for asteroid research and exploration, there are numerous engineering and industrial applications for near-term asteroid exploration. We have strong evidence that some asteroids are metal rich. Some are water and organic rich. They can be reached with a very low fuel cost compared to other solar system destinations. Once we reach them, there are efficient, simple extraction technologies available that would facilitate utilization. In addition, the costs of returning extracted resources from asteroids will be a fraction of the cost to return similar resources from the moon to Low Earth Orbit (LEO). These raw materials, extracted and shipped at relatively low cost, can be used to manufacture structures, fuel, and products which could be used to foster mankind s further exploration of the solar system. Asteroids also have the potential to offer transport to several destinations in the solar system

  3. Soils

    International Nuclear Information System (INIS)

    Freudenschuss, A.; Huber, S.; Riss, A.; Schwarz, S.; Tulipan, M.

    2001-01-01

    For Austria there exists a comprehensive soil data collection, integrated in a GIS (geographical information system). The content values of pollutants (cadmium, mercury, lead, copper, mercury, radio-cesium) are given in geographical charts and in tables by regions and by type of soil (forests, agriculture, greenland, others) for the whole area of Austria. Erosion effects are studied for the Austrian region. Legal regulations and measures for an effective soil protection, reduction of soil degradation and sustainable development in Austria and the European Union are discussed. (a.n.)

  4. Asteroid Redirection Mission Evaluation Using Multiple Landers

    Science.gov (United States)

    Bazzocchi, Michael C. F.; Emami, M. Reza

    2018-01-01

    In this paper, a low-thrust tugboat redirection method is assessed using multiple spacecraft for a target range of small near-Earth asteroids. The benefits of a landed configuration of tugboat spacecraft in formation are examined for the redirection of a near-Earth asteroid. The tugboat method uses a gimballed thruster with a highly collimated ion beam to generate a thrust on the asteroid. The target asteroid range focuses on near-Earth asteroids smaller than 150 m in diameter, and carbonaceous (C-type) asteroids, due to the volatiles available for in-situ utilization. The assessment focuses primarily on the three key parameters, i.e., the asteroid mass redirected, the timeframe for redirection, and the overall system cost. An evaluation methodology for each parameter is discussed in detail, and the parameters are employed to determine the expected return and feasibility of the redirection mission. The number of spacecraft employed is optimized along with the electrical power needed for each spacecraft to ensure the highest possible return on investment. A discussion of the optimization results and the benefits of spacecraft formation for the tugboat method are presented.

  5. Prospects for asteroid mass determination from close encounters between asteroids: ESA's Gaia space mission and beyond

    Science.gov (United States)

    Ivantsov, Anatoliy; Hestroffer, Daniel; Eggl, Siegfried

    2018-04-01

    We present a catalog of potential candidates for asteroid mass determination based on mutual close encounters of numbered asteroids with massive perturbers (D>20 km). Using a novel geometric approach tuned to optimize observability, we predict optimal epochs for mass determination observations. In contrast to previous studies that often used simplified dynamical models, we have numerically propagated the trajectories of all numbered asteroids over the time interval from 2013 to 2023 using relativistic equations of motion including planetary perturbations, J2 of the Sun, the 16 major asteroid perturbers and the perturbations due to non-sphericities of the planets. We compiled a catalog of close encounters between asteroids where the observable perturbation of the sky plane trajectory is greater than 0.5 mas so that astrometric measurements of the perturbed asteroids in the Gaia data can be leveraged. The catalog v1.0 is available at ftp://dosya.akdeniz.edu.tr/ivantsov.

  6. Infrared spectral reflectances of asteroid surfaces

    Science.gov (United States)

    Larson, H. P.; Veeder, G. J.

    1979-01-01

    This review compares the types of compositional information produced by three complementary techniques used in infrared observations of asteroid surfaces: broadband JHKL photometry, narrow band photometry, and multiplex spectroscopy. The high information content of these infrared observations permits definitive interpretations of asteroid surface compositions in terms of the major meteoritic minerals (olivine, pyroxene, plagioclase feldspar, hydrous silicates, and metallic Ni-Fe). These studies emphasize the individuality of asteroid surface compositions, the inadequacy of simple comparisons with spectra of meteorites, and the need to coordinate spectral measurements of all types to optimize diagnostic capabilities.

  7. Asteroid Spectroscopy: A Declaration of Independence

    Science.gov (United States)

    Bell, J. F.

    1995-09-01

    One of the shibboleths of asteroid spectroscopy for the past 25 years has been that a detailed knowledge of meteoritics is essential for proper interpretation of asteroid spectra. In fact, several recent spectroscopic discoveries have overturned long-standing models based on popular interpretations of meteorite data. A case can be made that spectroscopists could have made much faster progress if they had worked in total isolation from meteoritics. Consider the first three spectral classes identified in the 1970s: Vesta: The very first asteroid spectrum was unambigously basaltic, yet some meteoriticists have persistently resisted the obvious conclusion that the HED clan comes from Vesta, because A) Vesta is "impossibly" far from the known dynamical escape hatches; and B) the HED O-isotope data "establishes" a lirlk with pallasites and IIIAB irons, suggesting that their parent was some other completely disrupted asteroid. The discovery of a "dynamically impossible" extended family of basaltic fragments extending from Vesta to the 3:1 resonance [1] makes it clear that HEDs must originate on Vesta, and that dynamical, physical and isotopic arguments all led in the wrong direction. Stony: In the early 1970s meteorite fall statistics led to an expectation that many of the larger asteroids would be ordinary chondrites. When the most common class of asteroids proved to have silicate absorption bands, many concluded that these objects were the expected ordinary chondrite parent asteroids. The later discovery that S-type spectra do not actually resemble OCs was rationalized with imaginary "space weathering" processes (which have never been observed or simulated despite 20 years of wasted effort). Now that the real weathering trends in S asteroids have been resolved [2] and asteroids which actually do look like OCs discovered [3], it is clear that the eDhre controversy over S asteroid composition was a blind alley that could have been avoided by taking the spectra at face

  8. GeneDig: a web application for accessing genomic and bioinformatics knowledge.

    Science.gov (United States)

    Suciu, Radu M; Aydin, Emir; Chen, Brian E

    2015-02-28

    With the exponential increase and widespread availability of genomic, transcriptomic, and proteomic data, accessing these '-omics' data is becoming increasingly difficult. The current resources for accessing and analyzing these data have been created to perform highly specific functions intended for specialists, and thus typically emphasize functionality over user experience. We have developed a web-based application, GeneDig.org, that allows any general user access to genomic information with ease and efficiency. GeneDig allows for searching and browsing genes and genomes, while a dynamic navigator displays genomic, RNA, and protein information simultaneously for co-navigation. We demonstrate that our application allows more than five times faster and efficient access to genomic information than any currently available methods. We have developed GeneDig as a platform for bioinformatics integration focused on usability as its central design. This platform will introduce genomic navigation to broader audiences while aiding the bioinformatics analyses performed in everyday biology research.

  9. Digging Our Own Holes: Institutional Perspectives on Seismic Hazards

    Science.gov (United States)

    Stein, S.; Tomasello, J.

    2005-12-01

    It has been observed that there are no true students of the earth; instead, we each dig our own holes and sit in them. A similar situation arises in attempts to assess the hazards of earthquakes and other natural disasters and to develop strategies to mitigate them. Ideally, we would like to look at the interests of society as a whole and develop strategies that best balance hazard mitigation with alternative uses of resources. Doing so, however, is difficult for several reasons. First, estimating seismic hazards requires assumptions about the size, recurrence, and shaking from future earthquakes, none of which are well known. Second, we have to chose a definition of seismic hazard, which is even more arbitrary and at least as significant about future earthquakes. Third, mitigating the risks involves economic and policy issues as well as the scientific one of estimating the hazard itself and the engineering one of designing safe structures. As a result, different public and private organizations with different institutional perspectives naturally adopt different approaches. Most organizations have a single focus. For example, those focusing on economic development tend to discount hazards, whereas emergency management groups tend to accentuate them. Organizations with quasi-regulatory duties (BSSC, FEMA, USGS) focus on reducing losses in future earthquakes without considering the cost of mitigation measures or how this use of resources should be balanced with alternative uses of resources that could mitigate other losses. Some organizations, however, must confront these tradeoffs directly because they allocate resources internally. Hence hospitals implicitly trade off more earthquake resistant construction with treating uninsured patients, highway departments balance stronger bridges with other safety improvements, and schools balance safer buildings with after school programs. These choices are complicated by the fact that such infrastructure typically has longer

  10. Walking softly : using bioremediation to reclaim sites leaves a smaller footprint than traditional dig-and-dump technologies

    Energy Technology Data Exchange (ETDEWEB)

    Collison, M.

    2006-10-15

    Recent developments in the bioremediation industry in Alberta were outlined. The market for bioremediation services in the United States alone is estimated to hit $1 billion by 2010 and has become a staple of the U.S. Environmental Protection Agency's emergency management practices in the event of an oil spill. Alberta Environment has recently updated its policies and guidance documents on contaminated sites management, and is planning a manual that will include best bioremediation practices. Advances in the science and technology of bioremediation and a rise in environmental awareness have contributed to the sector's growth in recent years. In the past, oil companies in Alberta typically reclaimed sites by digging up contaminated soil and trucking it to landfills. Recent techniques developed by industry and bioremediation experts now mean that soil profiles can remain undisturbed, and biological treatment amendments are often introduced into the fractures to destroy contaminants where they lie. The National Research Council's Biotechnology Research Institute (NRC-BRI) is now conducting research to identify and profile unknown micro-organisms to improve conditions for the breakdown of toxins. Bioremediation techniques are also being used in urban redevelopment. It was concluded that while the environmental industry is regulatory-driven, many oil and mining companies are deciding to invest in remediation instead of waiting until a later date. A list of new bioremediation partnerships with industry, government and municipalities was also provided. 2 figs.

  11. Walking softly : using bioremediation to reclaim sites leaves a smaller footprint than traditional dig-and-dump technologies

    International Nuclear Information System (INIS)

    Collison, M.

    2006-01-01

    Recent developments in the bioremediation industry in Alberta were outlined. The market for bioremediation services in the United States alone is estimated to hit $1 billion by 2010 and has become a staple of the U.S. Environmental Protection Agency's emergency management practices in the event of an oil spill. Alberta Environment has recently updated its policies and guidance documents on contaminated sites management, and is planning a manual that will include best bioremediation practices. Advances in the science and technology of bioremediation and a rise in environmental awareness have contributed to the sector's growth in recent years. In the past, oil companies in Alberta typically reclaimed sites by digging up contaminated soil and trucking it to landfills. Recent techniques developed by industry and bioremediation experts now mean that soil profiles can remain undisturbed, and biological treatment amendments are often introduced into the fractures to destroy contaminants where they lie. The National Research Council's Biotechnology Research Institute (NRC-BRI) is now conducting research to identify and profile unknown micro-organisms to improve conditions for the breakdown of toxins. Bioremediation techniques are also being used in urban redevelopment. It was concluded that while the environmental industry is regulatory-driven, many oil and mining companies are deciding to invest in remediation instead of waiting until a later date. A list of new bioremediation partnerships with industry, government and municipalities was also provided. 2 figs

  12. PROPERTIES OF NEAR-SUN ASTEROIDS

    Energy Technology Data Exchange (ETDEWEB)

    Jewitt, David, E-mail: jewitt@ucla.edu [Department of Earth and Space Sciences and Department of Physics and Astronomy, University of California at Los Angeles, 595 Charles Young Drive East, Los Angeles, CA 90095-1567 (United States)

    2013-05-15

    Asteroids near the Sun can attain equilibrium temperatures sufficient to induce surface modification from thermal fracture, desiccation, and decomposition of hydrated silicates. We present optical observations of nine asteroids with perihelia <0.25 AU (sub-solar temperatures {>=}800 K) taken to search for evidence of thermal modification. We find that the broadband colors of these objects are diverse but statistically indistinguishable from those of planet-crossing asteroids having perihelia near 1 AU. Furthermore, images of these bodies taken away from perihelion show no evidence for on-going mass-loss (model-dependent limits {approx}<1 kg s{sup -1}) that might result from thermal disintegration of the surface. We conclude that, while thermal modification may be an important process in the decay of near-Sun asteroids and in the production of debris, our new data provide no evidence for it.

  13. Chelyabinsk: Portrait of an asteroid airburst

    Energy Technology Data Exchange (ETDEWEB)

    Kring, David A.; Boslough, Mark

    2014-09-01

    Video and audio from hundreds of smartphones and dashboard cameras combined with seismic, acoustic, and satellite measurements provide the first precise documentation of a 10 000-ton asteroid explosion.

  14. Shaping asteroid models using genetic evolution (SAGE)

    Science.gov (United States)

    Bartczak, P.; Dudziński, G.

    2018-02-01

    In this work, we present SAGE (shaping asteroid models using genetic evolution), an asteroid modelling algorithm based solely on photometric lightcurve data. It produces non-convex shapes, orientations of the rotation axes and rotational periods of asteroids. The main concept behind a genetic evolution algorithm is to produce random populations of shapes and spin-axis orientations by mutating a seed shape and iterating the process until it converges to a stable global minimum. We tested SAGE on five artificial shapes. We also modelled asteroids 433 Eros and 9 Metis, since ground truth observations for them exist, allowing us to validate the models. We compared the derived shape of Eros with the NEAR Shoemaker model and that of Metis with adaptive optics and stellar occultation observations since other models from various inversion methods were available for Metis.

  15. Chelyabinsk: Portrait of an asteroid airburst

    International Nuclear Information System (INIS)

    Kring, David A.; Boslough, Mark

    2014-01-01

    Video and audio from hundreds of smartphones and dashboard cameras combined with seismic, acoustic, and satellite measurements provide the first precise documentation of a 10 000-ton asteroid explosion

  16. SAWYER ASTEROID SPECTRA V1.1

    Data.gov (United States)

    National Aeronautics and Space Administration — Partial spectral data for the plots presented in S. Sawyer's PhD Thesis, 'A High Resolution Spectroscopic Survey of Low Albedo Main Belt Asteroids', 1991.

  17. Asteroid rotation excitation by subcatastrophic impacts

    Czech Academy of Sciences Publication Activity Database

    Henych, T.; Pravec, Petr

    2013-01-01

    Roč. 432, č. 2 (2013), s. 1623-1631 ISSN 0035-8711 Institutional support: RVO:67985815 Keywords : numerical methods * minor planets * general asteroids Subject RIV: BN - Astronomy , Celestial Mechanics, Astrophysics Impact factor: 5.226, year: 2013

  18. Families Among High-Inclination Asteroids

    Science.gov (United States)

    Novakovic, B.; Cellino, A.; Knezevic, Z.

    2012-05-01

    We review briefly the most important results of the classification of high-inclination asteroids into families performed by Novakovic et al.(Icarus, 2011,216) and present some new results about a very interesting (5438) Lorre cluster.

  19. ASTEROID SPIN VECTORS V4.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This is a tabulation of determinations of asteroid pole orientations gathered from the literature from 1932 through 1995. It is an updated (Dec. 1995) version of the...

  20. File list: NoD.Dig.10.AllAg.Intestinal_stem_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Dig.10.AllAg.Intestinal_stem_cells mm9 No description Digestive tract Intestina...l stem cells http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/NoD.Dig.10.AllAg.Intestinal_stem_cells.bed ...

  1. File list: NoD.Dig.20.AllAg.Intestinal_stem_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Dig.20.AllAg.Intestinal_stem_cells mm9 No description Digestive tract Intestina...l stem cells http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/NoD.Dig.20.AllAg.Intestinal_stem_cells.bed ...

  2. File list: InP.Dig.20.AllAg.Intestinal_stem_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Dig.20.AllAg.Intestinal_stem_cells mm9 Input control Digestive tract Intestinal... stem cells SRX856960,SRX1091861,SRX1091862,SRX193723 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Dig.20.AllAg.Intestinal_stem_cells.bed ...

  3. Asteroids Lightcurves Analysis: 2016 November - 2017 June

    Science.gov (United States)

    Carbognani, Albino; Bacci, Paolo; Buzzi, Luca

    2018-01-01

    Twelve near-Earth asteroids were observed from 2016 November through 2017 June to find the synodic rotation period and lightcurve amplitudes for each asteroid. Results are reported for 2329 Orthos, (138846) 2000 VJ61, (326683) 2002 WP, (489337) 2006 UM, (494706) 2005 GL9, 2005 TF, 2017 BJ30, 2017 BQ6, 2017 CS, 2017 DC36, 2017 GK4, and 2017 JA2.

  4. Dynamical properties of the Watsonia asteroid family

    Science.gov (United States)

    Tsirvoulis, G.; Novakovic, B.; Knezevic, Z.; Cellino, A.

    2014-07-01

    Introduction: In recent years, a rare class of asteroids has been discovered [1], with its distinguishing characteristic being the anomalous polarimetric properties of its members. Named Barbarians, after (234) Barbara, the prototype of the class, these asteroids show negative polarization at unusually high phase-angles compared to normal asteroids. Motivated by the fact that some of the few discovered Barbarians seemed to be related to the Watsonia asteroid family, Cellino et al. [2] performed a search for more Barbarians among its members. A positive result of this search led to the conclusion that Watsonia is indeed an important repository of Barbarian asteroids. Based on these findings, we decided to analyze this family in detail. Basic information: According to available data, Watsonia is an L-type asteroid family, located in the middle of the main asteroid belt (2.68 < a_{p} < 2.82 au), with low to moderate orbital eccentricities (0.1 < e_{p} < 0.15) and relatively high inclinations (16.5^{o} < i_{p} < 18^{o}). Methodology: The first step in our study is to derive a reliable list of Watsonia family members. To that purpose, we first calculate the synthetic proper elements [3] of an extended catalogue including numbered, as well as multi and single opposition asteroids, in a wide region around the family. To this catalogue we apply the Hierarchical Clustering Method (HCM)[4] to determine the membership of the family, coinciding with the requirement that all confirmed neighboring Barbarians are included (see figure). To detect potential interlopers and refine the membership list, additional data such as the SDSS colors and WISE albedos are used. Moreover, we identify all relevant resonances and analyze the dynamical characteristics of the region occupied by the family. Then we estimate the age of the family, and finally, we perform numerical integrations of test particles to investigate possible dynamical links to other known Barbarians and to the near

  5. Spectral investigation of two asteroidal fireballs

    Czech Academy of Sciences Publication Activity Database

    Borovička, Jiří

    2006-01-01

    Roč. 97, 3-4 (2006), s. 279-293 ISSN 0167-9295. [Asteroids, Comets, Meteors 2005. Búzios, 07.08.2005-12.08.2005] R&D Projects: GA ČR GA205/05/0543; GA ČR GA205/03/1404 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroids * meteors * spectroscopy Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.252, year: 2006

  6. The Asteroid Impact and Deflection Assessment Mission and its Potential Contributions to Human Exploration of Asteroids

    Science.gov (United States)

    Abell, Paul A.; Rivkin, Andy S.

    2014-01-01

    The joint ESA and NASA Asteroid Impact and Deflection Assessment (AIDA) mission will directly address aspects of NASA's Asteroid Initiative and will contribute to future human exploration. The NASA Asteroid Initiative is comprised of two major components: the Grand Challenge and the Asteroid Mission. The first component, the Grand Challenge, focuses on protecting Earth's population from asteroid impacts by detecting potentially hazardous objects with enough warning time to either prevent them from impacting the planet, or to implement civil defense procedures. The Asteroid Mission, involves sending astronauts to study and sample a near-Earth asteroid (NEA) prior to conducting exploration missions of the Martian system, which includes Phobos and Deimos. AIDA's primary objective is to demonstrate a kinetic impact deflection and characterize the binary NEA Didymos. The science and technical data obtained from AIDA will aid in the planning of future human exploration missions to NEAs and other small bodies. The dual robotic missions of AIDA, ESA's Asteroid Impact Monitor (AIM) and NASA's Double Asteroid Redirection Test (DART), will provide a great deal of technical and engineering data on spacecraft operations for future human space exploration while conducting in-depth scientific examinations of the binary target Didymos both prior to and after the kinetic impact demonstration. The knowledge gained from this mission will help identify asteroidal physical properties in order to maximize operational efficiency and reduce mission risk for future small body missions. The AIDA data will help fill crucial strategic knowledge gaps concerning asteroid physical characteristics that are relevant for human exploration considerations at similar small body destinations.

  7. Asteroid 'Bites the Dust' Around Dead Star

    Science.gov (United States)

    2009-01-01

    NASA's Spitzer Space Telescope set its infrared eyes upon the dusty remains of shredded asteroids around several dead stars. This artist's concept illustrates one such dead star, or 'white dwarf,' surrounded by the bits and pieces of a disintegrating asteroid. These observations help astronomers better understand what rocky planets are made of around other stars. Asteroids are leftover scraps of planetary material. They form early on in a star's history when planets are forming out of collisions between rocky bodies. When a star like our sun dies, shrinking down to a skeleton of its former self called a white dwarf, its asteroids get jostled about. If one of these asteroids gets too close to the white dwarf, the white dwarf's gravity will chew the asteroid up, leaving a cloud of dust. Spitzer's infrared detectors can see these dusty clouds and their various constituents. So far, the telescope has identified silicate minerals in the clouds polluting eight white dwarfs. Because silicates are common in our Earth's crust, the results suggest that planets similar to ours might be common around other stars.

  8. Abodes for life in carbonaceous asteroids?

    Science.gov (United States)

    Abramov, Oleg; Mojzsis, Stephen J.

    2011-05-01

    Thermal evolution models for carbonaceous asteroids that use new data for permeability, pore volume, and water circulation as input parameters provide a window into what are arguably the earliest habitable environments in the Solar System. Plausible models of the Murchison meteorite (CM) parent body show that to first-order, conditions suitable for the stability of liquid water, and thus pre- or post-biotic chemistry, could have persisted within these asteroids for tens of Myr. In particular, our modeling results indicate that a 200-km carbonaceous asteroid with a 40% initial ice content takes almost 60 Myr to cool completely, with habitable temperatures being maintained for ˜24 Myr in the center. Yet, there are a number of indications that even with the requisite liquid water, thermal energy sources to drive chemical gradients, and abundant organic "building blocks" deemed necessary criteria for life, carbonaceous asteroids were intrinsically unfavorable sites for biopoesis. These controls include different degrees of exothermal mineral hydration reactions that boost internal warming but effectively remove liquid water from the system, rapid (1-10 mm yr -1) inward migration of internal habitable volumes in most models, and limitations imposed by low permeabilities and small pore sizes in primitive undifferentiated carbonaceous asteroids. Our results do not preclude the existence of habitable conditions on larger, possibly differentiated objects such as Ceres and the Themis family asteroids due to presumed longer, more intense heating and possible long-lived water reservoirs.

  9. An ISU study of asteroid mining

    Science.gov (United States)

    Burke, J. D.

    During the 1990 summer session of the International Space University, 59 graduate students from 16 countries carried out a design project on using the resources of near-earth asteroids. The results of the project, whose full report is now available from ISU, are summarized. The student team included people in these fields: architecture, business and management, engineering, life sciences, physical sciences, policy and law, resources and manufacturing, and satellite applications. They designed a project for transporting equipment and personnel to a near-earth asteroid, setting up a mining base there, and hauling products back for use in cislunar space. In addition, they outlined the needed precursor steps, beginning with expansion of present ground-based programs for finding and characterizing near-earth asteroids and continuing with automated flight missions to candidate bodies. (To limit the summer project's scope the actual design of these flight-mission precursors was excluded.) The main conclusions were that asteroid mining may provide an important complement to the future use of lunar resources, with the potential to provide large amounts of water and carbonaceous materials for use off earth. However, the recovery of such materials from presently known asteroids did not show an economic gain under the study assumptions; therefore, asteroid mining cannot yet be considered a prospective business.

  10. International CJMT-1 Workshop on Asteroidal Science

    Science.gov (United States)

    Ip, Wing-Huen

    2014-03-01

    An international workshop on asteroidal science was held between October 16 and 17, 2012, at the Macau University of Science and Technology gathering together experts on asteroidal study in China, Japan, Macao and Taiwan. For this reason, we have called it CJMT-1 Workshop. Though small in sizes, the asteroids orbiting mainly between the orbit of Mars and of Jupiter have important influence on the evolution of the planetary bodies. Topics ranging from killer asteroids to space resources are frequently mentioned in news reports with prominence similar to the search for water on Mars. This also means that the study of asteroids is very useful in exciting the imagination and interest in science of the general public. Several Asian countries have therefore developed long-term programs integrating ground-based observations and space exploration with Japan being the most advanced and ambitious as demonstrated by the very successful Hayabusa mission to asteroid 25143 Itokawa. In this volume we will find descriptions of the mission planning of Hayabusa II to the C-type near-Earth asteroid, 1999 JU3. Not to be outdone, China's Chang-E 2 spacecraft was re-routed to a flyby encounter with asteroid 4179 Toutatis in December 2012. It is planned that in the next CJMT workshop, we will have the opportunity to learn more about the in-depth data analysis of the Toutatis observations and the progress reports on the Hayabusa II mission which launch date is set to be July 2014. Last but not least, the presentations on the ground-based facilities as described in this volume will pave the way for coordinated observations of asteroidal families and Trojan asteroids - across Asia from Taiwan to Uzbekistan. Such international projects will serve as an important symbol of good will and peaceful cooperation among the key members of this group. Finally, I want to thank the Space Science Institute, Macao University of Science and Technology, for generous support, and its staff members

  11. The Double Asteroid Redirection Test (DART)

    Science.gov (United States)

    Rivkin, A.; Cheng, A. F.; Stickle, A. M.; Richardson, D. C.; Barnouin, O. S.; Thomas, C.; Fahnestock, E.

    2017-12-01

    The Double Asteroid Redirection Test (DART) will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. DART is currently in Preliminary Design Phase ("Phase B"), and is part of the Asteroid Impact and Deflection Assessment (AIDA), a joint ESA-NASA cooperative project. The AIDA target is the near-Earth binary asteroid 65803 Didymos, an S-class system that will make a close approach to Earth in fall 2022. The DART spacecraft is designed to impact the Didymos secondary at 6 km/s and demonstrate the ability to modify its trajectory through momentum transfer. The primary goals of AIDA are (1) perform a full-scale demonstration of the spacecraft kinetic impact technique for deflection of an asteroid; (2) measure the resulting asteroid deflection, by targeting the secondary member of a binary NEO and measuring the resulting changes of the binary orbit; and (3) study hyper-velocity collision effects on an asteroid, validating models for momentum transfer in asteroid impacts. The DART impact on the Didymos secondary will change the orbital period of the binary by several minutes, which can be measured by Earth-based optical and radar observations. The baseline DART mission launches in late 2020 to impact the Didymos secondary in 2022 near the time of its close pass of Earth, which enables an array of ground- and space-based observatories to participate in gathering data. The AIDA project will provide the first measurements of momentum transfer efficiency from hyper-velocity kinetic impact at full scale on an asteroid, where the impact conditions of the projectile are known, and physical properties and internal structures of the target asteroid are characterized or constrained. The DART kinetic impact is predicted to make a crater of 6 to 17 meters diameter, depending on target physical properties, but will also release a large volume of particulate ejecta that may be directly observable from Earth or even resolvable as a

  12. Move/Bevæg Dig: An Interactive Sound Art Installation

    DEFF Research Database (Denmark)

    Hasse Jørgensen, Stina; Snyder, Jeff

    The Move/Bevæg Dig installation explores listeners' experiences of words as musical expressions and sonic experiences. Depending on how the listener moves around in an environment while wearing the custom - designed headphones, a voice will try to speak the words “Move” or “Bevæg Dig”, the Danish...

  13. Final disposal in deep boreholes using multiple geological barriers. Digging deeper for safety. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Bracke, Guido; Hurst, Stephanie; Merkel, Broder; Mueller, Birgit; Schilling, Frank

    2016-03-15

    The proceedings of the workshop on final disposal in deep boreholes using multiple geological barriers - digging deeper for safety include contributions on the following topics: international status and safety requirements; geological and physical barriers; deep drilling - shaft building; technical barriers and emplacement technology for high P/T conditions; recovery (waste retrieval); geochemistry and monitoring.

  14. Nest Digging by Leaf-Cutting Ants: Effect of Group Size and Functional Structures

    Directory of Open Access Journals (Sweden)

    Roberto da Silva Camargo

    2012-01-01

    Full Text Available Leaf-cutting ant workers dig underground chambers, for housing their symbiotic fungus, interconnected by a vast quantity of tunnels whose function is to permit the entrance of food (leaves, gaseous exchanges, and movement of workers, offspring, and the queen. Digging is a task executed by a group of workers, but little is known about the group effect and group-constructed functional structures. Thus, we analyzed the structures formed by worker groups (5, 10, 20, and 40 individuals of the leaf-cutting ant, Atta sexdens rubropilosa, for 2 days of excavation. The digging arena was the same for the 4 groups, with each group corresponding to a different density. Our results verified a pattern of tunneling by the workers, but no chamber was constructed. The group effect is well known, since the 40-worker group dug significantly more than the groups of 5, 10, and 20. These groups did not differ statistically from each other. Analysis of load/worker verified that workers of the smallest group carried the greatest load. Our paper demonstrates the group effect on the digging of nests, namely, that excavation is proportional to group size, but without emergence of a functional structure such as a chamber.

  15. Scratch and Dig analýza povrchových vad pro zrcadla Metis

    Czech Academy of Sciences Publication Activity Database

    Špína, Michal; Procháska, František; Melich, Radek

    2017-01-01

    Roč. 62, č. 1 (2017), s. 11-13 ISSN 0447-6441 R&D Projects: GA MŠk(CZ) LO1206 Institutional support: RVO:61389021 Keywords : Surface imperfection * Scratch and dig analysis * optical surface evaluation Subject RIV: JS - Reliability ; Quality Management, Testing OBOR OECD: Audio engineering, reliability analysis

  16. Sensitivity of Asteroid Impact Risk to Uncertainty in Asteroid Properties and Entry Parameters

    Science.gov (United States)

    Wheeler, Lorien; Mathias, Donovan; Dotson, Jessie L.; NASA Asteroid Threat Assessment Project

    2017-10-01

    A central challenge in assessing the threat posed by asteroids striking Earth is the large amount of uncertainty inherent throughout all aspects of the problem. Many asteroid properties are not well characterized and can range widely from strong, dense, monolithic irons to loosely bound, highly porous rubble piles. Even for an object of known properties, the specific entry velocity, angle, and impact location can swing the potential consequence from no damage to causing millions of casualties. Due to the extreme rarity of large asteroid strikes, there are also large uncertainties in how different types of asteroids will interact with the atmosphere during entry, how readily they may break up or ablate, and how much surface damage will be caused by the resulting airbursts or impacts.In this work, we use our Probabilistic Asteroid Impact Risk (PAIR) model to investigate the sensitivity of asteroid impact damage to uncertainties in key asteroid properties, entry parameters, or modeling assumptions. The PAIR model combines physics-based analytic models of asteroid entry and damage in a probabilistic Monte Carlo framework to assess the risk posed by a wide range of potential impacts. The model samples from uncertainty distributions of asteroid properties and entry parameters to generate millions of specific impact cases, and models the atmospheric entry and damage for each case, including blast overpressure, thermal radiation, tsunami inundation, and global effects. To assess the risk sensitivity, we alternately fix and vary the different input parameters and compare the effect on the resulting range of damage produced. The goal of these studies is to help guide future efforts in asteroid characterization and model refinement by determining which properties most significantly affect the potential risk.

  17. Asteroid mass estimation using Markov-chain Monte Carlo

    Science.gov (United States)

    Siltala, Lauri; Granvik, Mikael

    2017-11-01

    Estimates for asteroid masses are based on their gravitational perturbations on the orbits of other objects such as Mars, spacecraft, or other asteroids and/or their satellites. In the case of asteroid-asteroid perturbations, this leads to an inverse problem in at least 13 dimensions where the aim is to derive the mass of the perturbing asteroid(s) and six orbital elements for both the perturbing asteroid(s) and the test asteroid(s) based on astrometric observations. We have developed and implemented three different mass estimation algorithms utilizing asteroid-asteroid perturbations: the very rough 'marching' approximation, in which the asteroids' orbital elements are not fitted, thereby reducing the problem to a one-dimensional estimation of the mass, an implementation of the Nelder-Mead simplex method, and most significantly, a Markov-chain Monte Carlo (MCMC) approach. We describe each of these algorithms with particular focus on the MCMC algorithm, and present example results using both synthetic and real data. Our results agree with the published mass estimates, but suggest that the published uncertainties may be misleading as a consequence of using linearized mass-estimation methods. Finally, we discuss remaining challenges with the algorithms as well as future plans.

  18. SynDIG4/Prrt1 Is Required for Excitatory Synapse Development and Plasticity Underlying Cognitive Function

    Directory of Open Access Journals (Sweden)

    Lucas Matt

    2018-02-01

    Full Text Available Altering AMPA receptor (AMPAR content at synapses is a key mechanism underlying the regulation of synaptic strength during learning and memory. Previous work demonstrated that SynDIG1 (synapse differentiation-induced gene 1 encodes a transmembrane AMPAR-associated protein that regulates excitatory synapse strength and number. Here we show that the related protein SynDIG4 (also known as Prrt1 modifies AMPAR gating properties in a subunit-dependent manner. Young SynDIG4 knockout (KO mice have weaker excitatory synapses, as evaluated by immunocytochemistry and electrophysiology. Adult SynDIG4 KO mice show complete loss of tetanus-induced long-term potentiation (LTP, while mEPSC amplitude is reduced by only 25%. Furthermore, SynDIG4 KO mice exhibit deficits in two independent cognitive assays. Given that SynDIG4 colocalizes with the AMPAR subunit GluA1 at non-synaptic sites, we propose that SynDIG4 maintains a pool of extrasynaptic AMPARs necessary for synapse development and function underlying higher-order cognitive plasticity.

  19. Binaries and triples among asteroid pairs

    Science.gov (United States)

    Pravec, Petr; Scheirich, Peter; Kušnirák, Peter; Hornoch, Kamil; Galád, Adrián

    2015-08-01

    Despite major achievements obtained during the past two decades, our knowledge of the population and properties of small binary and multiple asteroid systems is still far from advanced. There is a numerous indirect evidence for that most small asteroid systems were formed by rotational fission of cohesionless parent asteroids that were spun up to the critical frequency presumably by YORP, but details of the process are lacking. Furthermore, as we proceed with observations of more and more binary and paired asteroids, we reveal new facts that substantially refine and sometimes change our understanding of the asteroid systems. One significant new finding we have recently obtained is that primaries of many asteroid pairs are actually binary or triple systems. The first such case found is (3749) Balam (Vokrouhlický, ApJL 706, L37, 2009). We have found 9 more binary systems among asteroid pairs within our ongoing NEOSource photometric project since October 2012. They are (6369) 1983 UC, (8306) Shoko, (9783) Tensho-kan, (10123) Fideoja, (21436) Chaoyichi, (43008) 1999 UD31, (44620) 1999 RS43, (46829) 1998 OS14 and (80218) 1999 VO123. We will review their characteristics. These paired binaries as we call them are mostly similar to binaries in the general ("background") population (of unpaired asteroids), but there are a few trends. The paired binaries tend to have larger secondaries with D_2/D_1 = 0.3 to 0.5 and they also tend to be wider systems with 8 of the 10 having orbital periods between 30 and 81 hours, than average among binaries in the general population. There may be also a larger fraction of triples; (3749) Balam is a confirmed triple, having a larger close and a smaller distant satellite, and (8306) Shoko and (10123) Fideoja are suspect triples as they show additional rotational lightcurve components with periods of 61 and 38.8 h that differ from the orbital period of 36.2 and 56.5 h, respectively. The unbound secondaries tend to be of the same size or

  20. THERMAL TOMOGRAPHY OF ASTEROID SURFACE STRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Alan W.; Drube, Line, E-mail: alan.harris@dlr.de [German Aerospace Center (DLR) Institute of Planetary Research, Rutherfordstrasse 2, D-12489 Berlin (Germany)

    2016-12-01

    Knowledge of the surface thermal inertia of an asteroid can provide insight into its surface structure: porous material has a lower thermal inertia than rock. We develop a means to estimate thermal inertia values of asteroids and use it to show that thermal inertia appears to increase with spin period in the case of main-belt asteroids (MBAs). Similar behavior is found on the basis of thermophysical modeling for near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. Our results are consistent with a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids and have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Evidence of a rapid increase of thermal inertia with depth is also an important result for studies of the ejecta-enhanced momentum transfer of impacting vehicles (“kinetic impactors”) in planetary defense.

  1. Matched Filter Processing for Asteroid Detection

    Science.gov (United States)

    Gural, Peter S.; Larsen, Jeffrey A.; Gleason, Arianna E.

    2005-10-01

    Matched filter (MF) processing has been shown to provide significant performance gains when processing stellar imagery used for asteroid detection, recovery, and tracking. This includes extending detection ranges to fainter magnitudes at the noise limit of the imagery and operating in dense cluttered star fields as encountered at low Galactic latitudes. The MF software has been shown to detect 40% more asteroids in high-quality Spacewatch imagery relative to the currently implemented approaches, which are based on moving target indicator (MTI) algorithms. In addition, MF detections were made in dense star fields and in situations in which the asteroid was collocated with a star in an image frame, cases in which the MTI algorithms failed. Thus, using legacy sensors and optics, improved detection sensitivity is achievable by simply upgrading the image-processing stream. This in turn permits surveys of the near-Earth asteroid (NEA) population farther from opposition, for smaller sizes, and in directions previously inaccessible to current NEA search programs. A software package has been developed and made available on the NASA data services Web site that can be used for asteroid detection and recovery operations utilizing the enhanced performance capabilities of MF processing.

  2. Spectroscopy and Photometry of CAI-rich asteroids

    Science.gov (United States)

    Tanga, P.; Devogele, M.; Bendjoya, Ph.; Cellino, A.; Surdej, J.

    2017-09-01

    Asteroids with an anomalous amount of primitive elements, formed in ancient times in the solar nebula, exist. Our study confirms their nature and provides hints to the interpretation of the ancient evolution of asteroids.

  3. SMALL MAIN-BELT ASTEROID SPECTROSCOPIC SURVEY, PHASE II

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains visible-wavelength (0.435-0.925 micron) spectra for 1341 main-belt asteroids observed during the second phase of the Small Main-belt Asteroid...

  4. Stability Analysis of Spacecraft Motion in the Vicinity of Asteroids

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of my proposal is to determine the stability of a spacecraft when in the vicinity of an asteroid. Orbiting an asteroid is a difficult task. The unique...

  5. Rock legends the asteroids and their discoverers

    CERN Document Server

    Murdin, Paul

    2016-01-01

    This book relates the history of asteroid discoveries and christenings, from those of the early pioneering giants of Hersehel and Piazzi to modern-day amateurs. Moving from history and anecdotal information to science, the book's structure is provided by the names of the asteroids, including one named after the author. Free from a need to conform to scientific naming conventions, the names evidence hero-worship, sycophancy, avarice, vanity, whimsy, erudition and wit, revealing the human side of astronomers, especially where controversy has followed the christening. Murdin draws from extensive historical records to explore the debate over these names. Each age reveals its own biases and preferences in the naming process. < Originally regarded as “vermin of the skies,” asteroids are minor planets, rocky scraps left over from the formation of the larger planets, or broken fragments of worlds that have collided. Their scientific classification as “minor” planets makes them seem unimportant, but over th...

  6. SAFARI: Searching Asteroids For Activity Revealing Indicators

    Science.gov (United States)

    Curtis, Anthony; Chandler, Colin Orion; Mommert, Michael; Sheppard, Scott; Trujillo, Chadwick A.

    2018-06-01

    We present results on one of the deepest and widest systematic searches for active asteroids, objects in the main-belt which behave dynamically like asteroids but display comet-like comae. This activity comes from a variety of sources, such as the sublimation of ices or rotational breakup, the former of which offers an opportunity to study a family of protoplanetary ices different than those seen in comets and Kuiper Belt objects. Indications of activity may be detected through visual or spectroscopic evidence of gas or dust emissions. However, these objects are still poorly understood, with only about 25 identified to date. We looked for activity indicators with a pipeline that examined ~35,000 deep images taken with the Dark Energy Camera (DECam) mounted on the 4-meter Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile. Our pipeline was configured to perform astrometry on DECam images and produce thumbnail images of known asteroids in the field to be examined by eye for signs of activity. We detected three previously identified active asteroids, one of which has shown repeated signs of activity in these data. Our proof of concept demonstrates 1) our novel informatics approach can locate active asteroids 2) DECam data are well suited to search for active asteroids. We will discuss the design structure of our pipeline, adjustments that had to be made for the specific dataset to improve performance, and the the significance of detecting activity in the main-belt. The authors acknowledge funding for this project through NSF grant number AST-1461200.

  7. Cosmic "Dig" Reveals Vestiges of the Milky Way's Building Blocks

    Science.gov (United States)

    2009-11-01

    Peering through the thick dust clouds of our galaxy's "bulge" (the myriads of stars surrounding its centre), and revealing an amazing amount of detail, a team of astronomers has unveiled an unusual mix of stars in the stellar grouping known as Terzan 5. Never observed anywhere in the bulge before, this peculiar "cocktail" of stars suggests that Terzan 5 is in fact one of the bulge's primordial building blocks, most likely the relic of a proto-galaxy that merged with the Milky Way during its very early days. "The history of the Milky Way is encoded in its oldest fragments, globular clusters and other systems of stars that have witnessed the entire evolution of our galaxy," says Francesco Ferraro from the University of Bologna, lead author of a paper appearing in this week's issue of the journal Nature. "Our study opens a new window on yet another piece of our galactic past." Like archaeologists, who dig through the dust piling up on top of the remains of past civilisations and unearth crucial pieces of the history of mankind, astronomers have been gazing through the thick layers of interstellar dust obscuring the bulge of the Milky Way and have unveiled an extraordinary cosmic relic. The target of the study is the star cluster Terzan 5. The new observations show that this object, unlike all but a few exceptional globular clusters, does not harbour stars which are all born at the same time - what astronomers call a "single population" of stars. Instead, the multitude of glowing stars in Terzan 5 formed in at least two different epochs, the earliest probably some 12 billion years ago and then again 6 billion years ago. "Only one globular cluster with such a complex history of star formation has been observed in the halo of the Milky Way: Omega Centauri," says team member Emanuele Dalessandro. "This is the first time we see this in the bulge." The galactic bulge is the most inaccessible region of our galaxy for astronomical observations: only infrared light can

  8. The DLR AsteroidFinder for NEOs

    Science.gov (United States)

    Mottola, Stefano; Kuehrt, Ekkehard; Michaelis, Harald; Hoffmann, Harald; Spietz, Peter; Jansen, Frank; Thimo Grundmann, Jan; Hahn, Gerhard; Montenegro, Sergio; Findlay, Ross; Boerner, Anko; Messina, Gabriele; Behnke, Thomas; Tschentscher, Matthias; Scheibe, Karsten; Mertens, Volker; Heidecke, Ansgar

    Potential Earth-impacting asteroids that spend most of their time interior to Earth's orbit are extremely difficult to be observed from the ground and remain largely undetected. Firstly, they are mostly located at small solar elongations, where the sky brightness and their faintness due to the large phase angle prevents their discovery. Secondly, these objects tend to have very long synodic orbital periods, which makes observation opportunities rare and impact warning times short. Because of these limitations, even the advent of next generation ground-based asteroid surveys is not likely to radically improve the situation (Veres et al. Icarus 203, p472, 2009). On the other hand, a small satellite with a suitable design can observe close to the Sun and detect these objects efficiently against a dark sky background. For this reason, DLR, the German Aerospace Center, has selected AsteroidFinder as the first experiment to be launched under its new compact satellite national program. The primary goal of the mission is to detect and characterize Near Earth Objects (NEOs), with a particular focus on the population of objects completely contained within Earth's orbit (IEOs or Inner Earth Objects). Current dynamical models predict the existence of more than 1000 such objects down to a size of 100m, of which, due to the abovementioned observation difficulties, only 10 have been discovered to date. Benefitting from the vantage point of a Low Earth Orbit (LEO), AsteroidFinder makes use of a small optical telescope to scan those regions of the sky that are close to the Sun, and therefore beyond the reach of ground based observatories. By estimating the population, the size and the orbital distribution of IEOs, AsteroidFinder will contribute to our knowledge of the inner Solar System, and to the assessment of the impact hazard for the Earth. A secondary goal of the mission is to demonstrate techniques that enable the space-based detection of space debris in the cm size range

  9. Dust bands in the asteroid belt

    International Nuclear Information System (INIS)

    Sykes, M.V.; Greenberg, R.; Dermott, S.F.; Nicholson, P.D.; Burns, J.A.

    1989-01-01

    This paper describes the original IRAS observations leading to the discovery of the three dust bands in the asteroid belt and the analysis of data. Special attention is given to an analytical model of the dust band torus and to theories concerning the origin of the dust bands, with special attention given to the collisional equilibrium (asteroid family), the nonequilibrium (random collision), and the comet hypotheses of dust-band origin. It is noted that neither the equilibrium nor nonequilibrium models, as currently formulated, present a complete picture of the IRAS dust-band observations. 32 refs

  10. Asteroid families - Physical properties and evolution

    International Nuclear Information System (INIS)

    Chapman, C.R.; Paolicchi, P.; Zappala, V.; Binzel, R.P.; Bell, J.F.

    1989-01-01

    Asteroid families are considered to be fragments from collisional destruction of precursor bodies. However, results available on the inferred mineralogy, size distributions, and spins of family members do not confirm the expectations of the traditional model. Only a handful of nearly 100 proposed families, most of them populous, have distributions of inferred mineralogies consistent with simple cosmochemical models for parent bodies. It is suggested that most catastrophic collisions may not result in observable families, but rather in a spray of smaller particles, thus accounting for the small number of confirmed and consistent families, despite evidence for extensive collisional evolution of asteroids. 52 refs

  11. Veritas Asteroid Family Still Holds Secrets?

    Science.gov (United States)

    Novakovic, B.

    2012-12-01

    Veritas asteroid family has been studied for about two decades. These studies have revealed many secrets, and a respectable knowledge about this family had been collected. Here I will present many of these results and review the current knowledge about the family. However, despite being extensively studied, Veritas family is still a mystery. This will be illustrated through the presentation of the most interesting open problems. Was there a secondary collision within this family? Does asteroid (490) Veritas belong to the family named after it? How large was the parent body of the family? Finally, some possible directions for future studies that aims to address these questions are discussed as well.

  12. Capturing near-Earth asteroids around Earth

    Science.gov (United States)

    Hasnain, Zaki; Lamb, Christopher A.; Ross, Shane D.

    2012-12-01

    The list of detected near-Earth asteroids (NEAs) is constantly growing. NEAs are likely targets for resources to support space industrialization, as they may be the least expensive source of certain needed raw materials. The limited supply of precious metals and semiconducting elements on Earth may be supplemented or even replaced by the reserves floating in the form of asteroids around the solar system. Precious metals make up a significant fraction NEAs by mass, and even one metallic asteroid of ˜1km size and fair enrichment in platinum-group metals would contain twice the tonnage of such metals already harvested on Earth. There are ˜1000 NEAs with a diameter of greater than 1 km. Capturing these asteroids around the Earth would expand the mining industry into an entirely new dimension. Having such resources within easy reach in Earth's orbit could provide an off-world environmentally friendly remedy for impending terrestrial shortages, especially given the need for raw materials in developing nations. In this paper, we develop and implement a conceptually simple algorithm to determine trajectory characteristics necessary to move NEAs into capture orbits around the Earth. Altered trajectories of asteroids are calculated using an ephemeris model. Only asteroids of eccentricity less than 0.1 have been studied and the model is restricted to the ecliptic plane for simplicity. We constrain the time of retrieval to be 10 years or less, based on considerations of the time to return on investment. For the heliocentric phase, constant acceleration is assumed. The acceleration required for transporting these asteroids from their undisturbed orbits to the sphere of influence of the Earth is the primary output, along with the impulse or acceleration necessary to effect capture to a bound orbit once the Earth's sphere of influence is reached. The initial guess for the constant acceleration is provided by a new estimation method, similar in spirit to Edelbaum's. Based on the

  13. Hungaria asteroid region telescopic spectral survey (HARTSS) I: Stony asteroids abundant in the Hungaria background population

    Science.gov (United States)

    Lucas, Michael P.; Emery, Joshua P.; Pinilla-Alonso, Noemi; Lindsay, Sean S.; Lorenzi, Vania

    2017-07-01

    The Hungaria asteroids remain as survivors of late giant planet migration that destabilized a now extinct inner portion of the primordial asteroid belt and left in its wake the current resonance structure of the Main Belt. In this scenario, the Hungaria region represents a ;purgatory; for the closest, preserved samples of the asteroidal material from which the terrestrial planets accreted. Deciphering the surface composition of these unique samples may provide constraints on the nature of the primordial building blocks of the terrestrial planets. We have undertaken an observational campaign entitled the Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS) to record near-infrared (NIR) reflectance spectra in order to characterize their taxonomy, surface mineralogy, and potential meteorite analogs. The overall objective of HARTSS is to evaluate the compositional diversity of asteroids located throughout the Hungaria region. This region harbors a collisional family of Xe-type asteroids, which are situated among a background (i.e., non-family) of predominantly S-complex asteroids. In order to assess the compositional diversity of the Hungaria region, we have targeted background objects during Phase I of HARTSS. Collisional family members likely reflect the composition of one original homogeneous parent body, so we have largely avoided them in this phase. We have employed NIR instruments at two ground-based telescope facilities: the NASA Infrared Telescope Facility (IRTF), and the Telescopio Nazionale Galileo (TNG). Our data set includes the NIR spectra of 42 Hungaria asteroids (36 background; 6 family). We find that stony S-complex asteroids dominate the Hungaria background population (29/36 objects; ∼80%). C-complex asteroids are uncommon (2/42; ∼5%) within the Hungaria region. Background S-complex objects exhibit considerable spectral diversity as band parameter measurements of diagnostic absorption features near 1- and 2-μm indicate that several

  14. Guided asteroid deflection by kinetic impact: Mapping keyholes to an asteroid's surface

    Science.gov (United States)

    Chesley, S.; Farnocchia, D.

    2014-07-01

    The kinetic impactor deflection approach is likely to be the optimal deflection strategy in most real-world cases, given the likelihood of decades of warning time provided by asteroid search programs and the probable small size of the next confirmed asteroid impact that would require deflection. However, despite its straightforward implementation, the kinetic impactor approach can have its effectiveness limited by the astrodynamics that govern the impactor spacecraft trajectory. First, the deflection from an impact is maximized when the asteroid is at perihelion, while an impact near perihelion can in some cases be energetically difficult to implement. Additionally, the asteroid change in velocity Δ V should aligned with the target's heliocentric velocity vector in order to maximize the deflection at a potential impact some years in the future. Thus the relative velocity should be aligned with or against the heliocentric velocity, which implies that the impactor and asteroid orbits should be tangent at the point of impact. However, for natural bodies such as meteorites colliding with the Earth, the relative velocity vectors tend to cluster near the sunward or anti- sunward directions, far from the desired direction. This is because there is generally a significant crossing angle between the orbits of the impactor and target and an impact at tangency is unusual. The point is that hitting the asteroid is not enough, but rather we desire to hit the asteroid at a point when the asteroid and spacecraft orbits are nearly tangent and when the asteroid is near perihelion. However, complicating the analysis is the fact that the impact of a spacecraft on an asteroid would create an ejecta plume that is roughly normal to the surface at the point of impact. This escaping ejecta provides additional momentum transfer that generally adds to the effectiveness of a kinetic deflection. The ratio β between the ejecta momentum and the total momentum (ejecta plus spacecraft) can

  15. Dynamic wind turbine models in power system simulation tool DIgSILENT

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Iov, F.; Sørensen, Poul Ejnar

    , connection of the wind turbine at different types of grid and storage systems. Different control strategies have been developed and implemented for these wind turbine concepts, their performance in normal or fault operation being assessed and discussed by means of simulations. The described control......This report presents a collection of models and control strategies developed and implemented in the power system simulation tool PowerFactory DIgSILENT for different wind turbine concepts. It is the second edition of Risø-R-1400(EN) and it gathers and describes a whole wind turbine model database...... of the interaction between the mechanical structure of the wind turbine and the electrical grid during different operational modes. The report provides thus a description of the wind turbines modelling, both at a component level and at a system level. The report contains both the description of DIgSILENT built...

  16. A non-digging zoobenthivorous fish attracts two opportunistic predatory fish associates

    Directory of Open Access Journals (Sweden)

    Cristina Sazima

    Full Text Available Following behaviour among reef fishes involves mostly a digging nuclear species while foraging, which attracts opportunistic followers preying on the exposed organisms. The flying gurnard Dactylopterus volitans preys on benthic animals, mostly crustaceans and small fishes, scratching and probing the bottom with the inner rays of its pectoral fins. We recorded the flying gurnard being followed by two opportunistic predators, the yellow jack Caranx bartholomaei and the coney Cephalopholis fulva at Fernando de Noronha, off northeast Brazil. Albeit not actually digging the substrate, the flying gurnard acts as a nuclear species by exploring algae tufts and by its wandering near the boulders and ledges, disturbing and flushing out hidden animals which thus become available to predation.

  17. Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS): Stony Asteroids Abundant in the Background and Family Populations

    Science.gov (United States)

    Lucas, Michael P.; Emery, Joshua P.; Pinilla-Alonso, Noemi; Lindsay, Sean S.; Lorenzi, Vania

    2016-10-01

    The Hungaria region represents a "purgatory" for the closest, preserved samples of the material from which the terrestrial planets accreted. The Hungaria region harbors a collisional family of Xe-type asteroids, which are situated among a background of predominantly S-complex asteroids. Deciphering their surface composition may provide constraints on the nature of the primordial building blocks of the terrestrial planets. We hypothesize that planetesimals in the inner part of the primordial asteroid belt experienced partial- to full-melting and differentiation, the Hungaria region should retain any petrologically-evolved material that formed there.We have undertaken an observational campaign entitled the Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS) to record near-infrared (NIR) spectra to characterize taxonomy, surface mineralogy, and potential meteorite analogs. We used NIR instruments at two ground-based facilities (NASA IRTF; TNG). Our data set includes spectra of 82 Hungaria asteroids (61 background; 21 family), 65 were observed during HARTSS. We compare S-complex background asteroids to calibrations developed via laboratory analyses of ordinary chondrites, and to our analyses (EPMA, XRD, VIS+NIR spectra) of 11 primitive achondrite (acapulcoite-lodranite clan) meteorites.We find that stony S-complex asteroids dominate the Hungaria background population (~80%). Background objects exhibit considerable spectral diversity, when quantified by spectral band parameter measurements, translates to a variety of surface compositions. Two main meteorite groups are represented within the Hungaria background: unmelted, nebular L chondrites (and/or L chondrites), and partially-melted primitive achondrites. H-chondrite mineralogies appear to be absent from the Hungaria background. Xe-type Hungaria family members exhibit spectral homogeneity, consistent with the hypothesis that the family was derived from the disruption of a parent body analogous to an enstatite

  18. Twenty-one Asteroid Lightcurves at Asteroids Observers (OBAS) - MPPD: Nov 2016 - May 2017

    Science.gov (United States)

    Mas, Vicente; Fornas, G.; Lozano, Juan; Rodrigo, Onofre; Fornas, A.; Carreño, A.; Arce, Enrique; Brines, Pedro; Herrero, David

    2018-01-01

    We report on the analysis of photometric observations of 21 main-belt asteroids (MBA) done by Asteroids Observers (OBAS). This work is part of the Minor Planet Photometric Database task that was initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate and complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  19. Harmonic Domain Modelling of Transformer Core Nonlinearities Using the DIgSILENT PowerFactory Software

    OpenAIRE

    Bak, Claus Leth; Bak-Jensen, Birgitte; Wiechowski, Wojciech

    2008-01-01

    This paper demonstrates the results of implementation and verification of an already existing algorithm that allows for calculating saturation characteristics of singlephase power transformers. The algorithm was described for the first time in 1993. Now this algorithm has been implemented using the DIgSILENT Programming Language (DPL) as an external script in the harmonic domain calculations of a power system analysis tool PowerFactory [10]. The algorithm is verified by harmonic measurements ...

  20. Dynamic wind turbine models in power system simulation tool DIgSILENT

    OpenAIRE

    Hansen, A.D.; Jauch, C.; Sørensen, Poul Ejnar; Iov, F.; Blaabjerg, F.

    2004-01-01

    The present report describes the dynamic wind turbine models implemented in the power system simulation tool DIgSILENT (Version 12.0). The developed models are a part of the results of a national research project, whose overall objective is to create amodel database in different simulation tools. This model database should be able to support the analysis of the interaction between the mechanical structure of the wind turbine and the electrical grid during different operational modes. The repo...

  1. Asteroid-Generated Tsunami and Impact Risk

    Science.gov (United States)

    Boslough, M.; Aftosmis, M.; Berger, M. J.; Ezzedine, S. M.; Gisler, G.; Jennings, B.; LeVeque, R. J.; Mathias, D.; McCoy, C.; Robertson, D.; Titov, V. V.; Wheeler, L.

    2016-12-01

    The justification for planetary defense comes from a cost/benefit analysis, which includes risk assessment. The contribution from ocean impacts and airbursts is difficult to quantify and represents a significant uncertainty in our assessment of the overall risk. Our group is currently working toward improved understanding of impact scenarios that can generate dangerous tsunami. The importance of asteroid-generated tsunami research has increased because a new Science Definition Team, at the behest of NASA's Planetary Defense Coordinating Office, is now updating the results of a 2003 study on which our current planetary defense policy is based Our group was formed to address this question on many fronts, including asteroid entry modeling, tsunami generation and propagation simulations, modeling of coastal run-ups, inundation, and consequences, infrastructure damage estimates, and physics-based probabilistic impact risk assessment. We also organized the Second International Workshop on Asteroid Threat Assessment, focused on asteroid-generated tsunami and associated risk (Aug. 23-24, 2016). We will summarize our progress and present the highlights of our workshop, emphasizing its relevance to earth and planetary science. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000.

  2. The infrared spectrum of asteroid 433 Eros

    Science.gov (United States)

    Larson, H. P.; Fink, U.; Treffers, R. R.; Gautier, T. N., III

    1976-01-01

    The mineralogical composition of asteroid Eros has been determined from its infrared spectrum (0.9-2.7 micrometers; 28/cm resolution). Major minerals include metallic Ni-Fe and pyroxene; no spectroscopic evidence for olivine or plagioclase feldspar was found. The IR spectrum of Eros is most consistent with a stony-iron composition.

  3. Direct Detection of the Asteroidal YORP Effect

    Czech Academy of Sciences Publication Activity Database

    Lowry, S.C.; Fitzsimmons, A.; Pravec, Petr; Vokrouhlický, D.; Boehnhardt, H.; Taylor, P.A.; Margot, J. L.; Galád, Adrián; Irwin, M.; Irwin, J.; Kušnirák, Peter

    2007-01-01

    Roč. 316, č. 5822 (2007), s. 272-274 ISSN 0036-8075 R&D Projects: GA AV ČR IAA3003204 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroids rotation * near- Earth objects Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 26.372, year: 2007

  4. Photometric survey of asynchronous binary asteroids

    Czech Academy of Sciences Publication Activity Database

    Pravec, Petr; Scheirich, Peter; Kušnirák, Peter; Kotková, Lenka; Mottola, S.; Hahn, G.; Brown, P.; Esquerdo, G.; Kaiser, K.; Krzeminski, Z.; Pray, D. P.; Warner, B. D.; Harris, A. W.; Nolan, M. C.; Howell, E. S.; Benner, L. A. M.; Margot, J. L.; Galád, Adrián; Holliday, W.; Hicks, M. D.; Krugly, Yu. N.; Tholen, D.; Whiteley, R.; Marchis, F.; DeGraff, D. R.; Grauer, A.; Larson, S. M.; Velichko, F. P.; Cooney, W.R.; Stephens, R.; Zhu, J.; Kirsch, K.; Dyvig, R.; Snyder, L.; Reddy, V.; Moore, S.; Gajdoš, Š.; Világi, J.; Masi, G.; Higgins, D.; Funkhouser, G. M.; Knight, B.; Slivan, S. M.; Behrend, R.; Grenon, M.; Burki, G.; Roy, R.; Demeautis, C.; Matter, D.; Waelchli, N.; Revaz, Y.; Klotz, A.; Rieugné, M.; Thieri, P.; Cotrez, V.; Brunetto, L.; Kober, G.

    2006-01-01

    Roč. 181, č. 1 (2006), s. 63-93 ISSN 0019-1035 R&D Projects: GA ČR GA205/05/0604; GA AV ČR IAA3003204 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroids * binary * photometry Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.151, year: 2006

  5. Slowly rotating asteroid 1999 GU3

    Czech Academy of Sciences Publication Activity Database

    Pravec, Petr; Kotková, Lenka; Benner, L. A. M.; Ostro, S. J.; Hicks, M. D.; Jurgens, R. F.; Giorgini, I. D.; Slade, M. A.; Yeomans, D. K.; Rabinowitz, D. L.; Krugly, Yu. N.; Wolf, M.

    2000-01-01

    Roč. 148, č. 1 (2000), s. 589-593 ISSN 0019-1035 R&D Projects: GA AV ČR IAA3003708; GA ČR GA205/99/0255 Institutional research plan: CEZ:AV0Z1003909 Keywords : asteroids * rotation * photometry Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.651, year: 2000

  6. Asteroids Dynamic Site-AstDyS

    Science.gov (United States)

    Knezevic, Zoran; Milani, Andrea

    2012-08-01

    The AstDyS online information service (http://hamilton.dm.unipi.it/astdys/) contains data on numbered and multi - opposition asteroids, including orbital elements, their uncertainty, proper elements, ephemerides with uncertainty, and more. AstDyS also provides additional scientific output computed from the raw observational data. This value added currently includes: more accurate orbits computed with advanced dynamical and observational error model s; their uncertainty, as expressed by the covariance matrix formalism; ephemerides computed on request for each observer, with uncertainty; mean and proper orbital elements (for this output, AstDyS is the primary source worldwide); statistical quality control, providing a rigorous observational error model. All this is available with a sophisticated web interface, providing multiple search functions and online computations as well as complete orbital and residual files. There are several ways in which the A stDyS service could be expanded and improved in the next future, like the explicit classification of asteroids into asteroid families, the classification of resonant asteroids, and an updated self - consistent population model (to be used, e.g., for survey simulations). The IAU Division I endorsed the proposal for AstDyS to become an IAU (permanent) service, which would include the IAU supervision of the AstDyS system, keeping under control the quality of the work and the continuous update under conditions of scientific competition.

  7. Exogenous origin of hydration on asteroid (16) Psyche: the role of hydrated asteroid families

    Science.gov (United States)

    Avdellidou, C.; Delbo', M.; Fienga, A.

    2018-04-01

    Asteroid (16) Psyche, which for a long time was the largest M-type with no detection of hydration features in its spectrum, was recently discovered to have a weak 3-μm band and thus it was eventually added to the group of hydrated asteroids. Its relatively high density, in combination with the high radar albedo, led researchers to classify the asteroid as a metallic object. It is believed that it is possibly a core of a differentiated body, a remnant of `hit-and-run' collisions. The detection of hydration is, in principle, inconsistent with a pure metallic origin for this body. Here, we consider the scenario in which the hydration on its surface is exogenous and was delivered by hydrated impactors. We show that impacting asteroids that belong to families whose members have the 3-μm band can deliver hydrated material to Psyche. We developed a collisional model with which we test all dark carbonaceous asteroid families, which contain hydrated members. We find that the major source of hydrated impactors is the family of Themis, with a total implanted mass on Psyche of the order of ˜1014 kg. However, the hydrated fraction could be only a few per cent of the implanted mass, as the water content in carbonaceous chondrite meteorites, the best analogue for the Themis asteroid family, is typically a few per cent of their mass.

  8. Study of the Asteroid 2009 DL46

    Science.gov (United States)

    Vodniza, Alberto Quijano

    2017-06-01

    2009 DL46 was discovered by the Catalina Sky Survey on 2009-February 28. This asteroid has a diameter of about 194 meters (119 to 268 meters) [1], and Brian Warner has obtained a rotation period of at least 10 hours [2]. The asteroid 2009 DL46 flew past Earth on May 24/2016 at a distance of about 6.2 lunar distances (0.0158293668567628 A.U) [3]. The NEOWISE mission had a great likelihood to observing this asteroid in early May. Radiotelescopes of Goldstone and Arecibo had planned to make observations of 2009 DL46. “Using the Goldstone facility, we had planned to make radar observations of 2009 DL46” said Landis, Rob R. (HQ-DG000). This asteroid is on list for possible human mission targets. From our Observatory, located in Pasto-Colombia, we captured several pictures, videos and astrometry data during several hours during three days. Our data was published by the Minor Planet Center (MPC) and also appears at the web page of NEODyS [4]. The pictures and data of the asteroid were captured with the following equipment: CGE PRO 1400 CELESTRON (f/11 Schmidt-Cassegrain Telescope) and STL-1001 SBIG camera.. Astrometry was carried out, and we calculated the orbital elements. Summary and conclusions: We obtained the following orbital parameters: eccentricity = 0.30731 +/- 0.00025, semi-major axis = 1.460279 +/- 0.000532 A.U, orbital inclination = 7.9503 +/- 0.0048 deg, longitude of the ascending node = 63.45053 +/- 0.00034 deg, argument of perihelion = 159.8804 +/- 0.0024 deg, mean motion = 0.558535 +/- 0.000305 deg/d, perihelion distance = 1.01151363 +/- 3.39e-6 A.U, aphelion distance = 1.90904 +/- 0.00106 A.U, absolute magnitude = 22.5. The parameters were calculated based on 83 observations. Dates: 2016 May: 18 to 21 with mean residual = 0.29 arcseconds. The asteroid has an orbital period of 1.76 years (644.53 days).[1] http://newton.dm.unipi.it/neodys/index.php?pc=1.1.9&n=2009DL46.[2] http://echo.jpl.nasa.gov/asteroids/2009DL46/2009DL46_planning.html[3] http

  9. 3-µm Spectroscopy of Asteroid 16 Psyche

    Science.gov (United States)

    Takir, Driss; Reddy, Vishnu; Sanchez, Juan; Shepard, Michael K.

    2016-10-01

    Asteroid 16 Psyche, an M-type asteroid, is thought to be one of the most massive exposed iron metal object in the asteroid belt. The high radar albedos of Psyche suggest that this differentiated asteroid is dominantly composed of metal. Psyche was previously found to be featureless in the 3-µm spectral region. However, in our study we found that this asteroid exhibits a 3-µm absorption feature, possibly indicating the presence of hydrated silicates.We have observed Psyche in the 3-µm spectral region, using the long-wavelength cross-dispersed (LXD:1.9-4.2 µm) mode of the SpeX spectrograph/imager at the NASA Infrared Telescope Facility (IRTF). For data reduction, we used the IDL (Interactive Data Language)-based spectral reduction tool Spextool (v4.1). Psyche was observed over the course of three nights with an apparent visual magnitude of ~9.50: 8 December 2015 (3 sets), 9 December 2015 (1 set), and 10 March 2016 (1 set). These observations have revealed that Psyche may exhibit a 3-µm absorption feature, similar to the sharp group in the 2.9-3.3-µm spectral range. Psyche also exhibits an absorption feature similar to the one in Ceres and Ceres-like group in the spectral 3.3-4.0-µm range. These 3-µm observational results revealed that Psyche may not be as featureless as once thought in the 3-µm spectral region.Evidence for the 3-µm band was found on the surfaces of many M-type asteroids and a number of plausible alternative interpretations for the presence of this 3-µm band were previously suggested. These interpretations include the presence of anhydrous silicates containing structural OH, the presence of fluid inclusions, the presence of xenolithic hydrous meteorite components on asteroid surfaces from impacts, solar wind-implanted H, or the presence of troilite. The detection of the Ceres-like feature in the 3.3-4.0-µm spectral range, however, would rule out some of these alternative interpretations, especially the solar wind-implanted H.

  10. Asteroids from a Martian Mega Impact

    Science.gov (United States)

    Kohler, Susanna

    2018-04-01

    Like evidence left at a crime scene, the mineral olivine may be the clue that helps scientists piece together Marss possibly violent history. Could a long-ago giant impact have flung pieces of Mars throughout our inner solar system? Two researchers from the Tokyo Institute of Technology in Japan are on the case.A Telltale MineralOlivine, a mineral that is common in Earths subsurface but weathers quickly on the surface. Olivine is a major component of Marss upper mantle. [Wilson44691]Olivine is a major component of the Martian upper mantle, making up 60% of this region by weight. Intriguingly, olivine turns up in other places in our solar system too for instance, in seven out of the nine known Mars Trojans (a group of asteroids of unknown origin that share Marss orbit), and in the rare A-type asteroids orbiting in the main asteroid belt.How did these asteroids form, and why are they so olivine-rich? An interesting explanation has been postulated: perhaps this olivine all came from the same place Mars as the result of a mega impact billions of years ago.Evidence for ImpactMars bears plenty of signs pointing to a giant impact in its past. The northern and sourthern hemispheres of Mars look very different, a phenomenon referred to as the Mars hemisphere dichotomy. The impact of a Pluto-sized body could explain the smooth Borealis Basin that covers the northern 40% of Marss surface.This high-resolution topographic map of Mars reveals the dichotomy between its northern and sourthern hemispheres. The smooth region in the northern hemisphere, the Borealis basin, may have been formed when a giant object impacted Mars billions of years ago. [NASA/JPL/USGS]Other evidence piles up: Marss orbit location, its rotation speed, the presence of its two moons all could be neatly explained by a large impact around 4 billion years ago. Could such an impact have also strewn debris from Marss mantle across the solar system?To test this theory, we need to determine if a mega impact is

  11. Digging up the Earliest Astronomical Observatory in China

    Science.gov (United States)

    Li, Wei-Boa; Chen, Jiu-Jin

    2007-09-01

    At the town of Taosi, county of Xiangfen, Shanxi province the earliest (up to date about 4000 years ago) astronomical observatory and sacrificial altar relic was dug up, which consists of an observing site, some tamped soil columniations and slits between those columniations. This construction was used to observe the variations of the sunrise azimuth and determine the tropical year length in order to constitute the calendar. It is indicated from the simulated observations that the two slits located in the southeast and the northwest could be precisely used to determine the dates of the Winter Solstice and the Summer Solstice. Between those two slits there are 10 columniations which could indicate that the visual Sun moving from one columniation to another is a solar term. It implies that in the Emperor Yao time the calendar was the solar calendar in which one year was divided into 20 solar terms. The Yin-Yang five-element calendar, a 10-month calendar, in the very ancient time was based on this calendar.

  12. Geologic History of Asteroid 4 Vesta

    Science.gov (United States)

    Mittlefehldt, David W.

    2014-01-01

    Some types of meteorites - most irons, stony irons, some achondrites - hail from asteroids that were heated to the point where magmatism occurred within a very few million years of the formation of the earliest solids in the solar system. The largest clan of achondrites, the howardite, eucrite and diogenite (HED) meteorites, represent the crust of their parent asteroid]. Diogenites are cumulate harzburgites and orthopyroxenites from the lower crust whilst eucrites are basalts, diabases and cumulate gabbros from the upper crust. Howardites are impact-engendered breccias mostly of diogenites and eucrites. There remains only one large asteroid with a basaltic crust, 4 Vesta, which is thought to be the source of the HED clan. Differentiation models for Vesta are based on HED compositions. Proto-Vesta consisted of chondritic materials containing Al-26, a potent, short-lived heat source. Inferences from compositional data are that Vesta was melted to high degree (=50%) allowing homogenization of the silicate phase and separation of a metallic core. Convection of the silicate magma ocean allowed equilibrium crystallization, forming a harzburgitic mantle. After convective lockup occurred, melt collected between the mantle and the cool thermal boundary layer and underwent fractional crystallization forming an orthopyroxene-rich (diogenite) lower crust. The initial thermal boundary layer of chondritic material was replaced by a mafic upper crust through impact disruption and foundering. The mafic crust thickened over time as additional residual magma intrudes and penetrates the mafic crust forming plutons, dikes, sills and flows of cumulate and basaltic eucrite composition. This magmatic history may have taken only 2-3 Myr. This magma ocean scenario is at odds with a model of heat and magma transport that indicates that small degrees of melt would be rapidly expelled from source regions, precluding development of a magma ocean. Constraints from radiogenic Mg-26 distibutions

  13. Asteroid families from cratering: Detection and models

    Science.gov (United States)

    Milani, A.; Cellino, A.; Knežević, Z.; Novaković, B.; Spoto, F.; Paolicchi, P.

    2014-07-01

    A new asteroid families classification, more efficient in the inclusion of smaller family members, shows how relevant the cratering impacts are on large asteroids. These do not disrupt the target, but just form families with the ejecta from large craters. Of the 12 largest asteroids, 8 have cratering families: number (2), (4), (5), (10), (87), (15), (3), and (31). At least another 7 cratering families can be identified. Of the cratering families identified so far, 7 have >1000 members. This imposes a remarkable change from the focus on fragmentation families of previous classifications. Such a large dataset of asteroids believed to be crater ejecta opens a new challenge: to model the crater and family forming event(s) generating them. The first problem is to identify which cratering families, found by the similarity of proper elements, can be formed at once, with a single collision. We have identified as a likely outcome of multiple collisions the families of (4), (10), (15), and (20). Of the ejecta generated by cratering, only a fraction reaches the escape velocity from the surviving parent body. The distribution of velocities at infinity, giving to the resulting family an initial position and shape in the proper elements space, is highly asymmetric with respect to the parent body. This shape is deformed by the Yarkovsky effect and by the interaction with resonances. All the largest asteroids have been subjected to large cratering events, thus the lack of a family needs to be interpreted. The most interesting case is (1) Ceres, which is not the parent body of the nearby family of (93). Two possible interpretations of the low family forming efficiency are based on either the composition of Ceres with a significant fraction of ice, protected by a thin crust, or with the larger escape velocity of ~500 m/s.

  14. Near-Earth Asteroid Rendezvous: mission overview

    Science.gov (United States)

    Cheng, A. F.; Santo, A. G.; Heeres, K. J.; Landshof, J. A.; Farquhar, R. W.; Gold, R. E.; Lee, S. C.

    1997-10-01

    The Near-Earth Asteroid Rendezvous (NEAR) mission, the first launch of NASA's Discovery Program, will be the first mission to orbit an asteroid. NEAR will make the first comprehensive scientific measurements of an asteroid's surface composition, geology, physical properties, and internal structure. NEAR launched successfully on February 17, 1996, aboard a Delta II-7925. It will orbit the 20-km-diameter near-Earth asteroid 433 Eros for about 1 year, at a minimum orbit radius of about 35 km from the center of the asteroid. The NEAR is a solar-powered, three-axis stabilized spacecraft with a launch mass including propellant of 805 kg. NEAR uses X band telemetry to the NASA Deep Space Network, with the data rates at Eros up to 8.8 kbits/s using a 34-m High Efficiency (HEF) dish, and up to 26.5 kbits/s using a 70-m dish. A solid-state recorder is accommodated with a memory capacity of 1.8 Gbytes. Attitude control is to 1.7 mrad, line-of-sight pointing stability is within 50 μrad over 1 s, and post processing attitude knowledge is within 50 μrad. NEAR accommodates 56 kg of instruments and provides them with 84 W. The instruments are a multispectral imager (MSI), a near-infrared spectrograph (NIS), an X ray/gamma ray spectrometer (XRS/GRS), a magnetometer (MAG), and a laser rangefinder (NLR), while a radio science (RS) investigation uses the coherent X band transponder. NEAR will make a flyby of the C-type asteroid 253 Mathilde in June 1997 and will rendezvous with 433 Eros in February 1999. It will execute an initial slow flyby of Eros, with a flyby speed of 5 m/s and a closest approach distance of 500 km. Subsequently, its orbit will be lowered to 35 km. The NEAR Mission Operations Center and the Science Data Center are at the Johns Hopkins Applied Physics Laboratory. The Science Data Center will maintain the entire NEAR data set on-line, and data from all instruments can be accessed by every member of the NEAR Science Team. Data, including images, are released over

  15. Tracing meteorite source regions through asteroid spectroscopy

    Science.gov (United States)

    Thomas, Cristina Ana

    By virtue of their landing on Earth, meteorites reside in near-Earth object (NEO) orbits prior to their arrival. Thus the population of observable NEOs, in principle, gives the best representation of meteorite source bodies. By linking meteorites to NEOs, and linking NEOs to their most likely main-belt source locations, we seek to gain insight into the original solar system formation locations for different meteorite classes. To forge the first link between meteorites and NEOs, we have developed a three dimensional method for quantitative comparisons between laboratory measurements of meteorites and telescopic measurements of near-Earth objects. We utilize meteorite spectra from the Reflectance Experiment Laboratory (RELAB) database and NEO data from the SpeX instrument on the NASA Infrared Telescope Facility (IRTF). Using the Modified Gaussian Model (MGM) as a mathematical tool, we treat asteroid and meteorite spectra identically in the calculation of 1-micron and 2-micron geometric band centers and their band area ratios (BARs). Using these identical numerical parameters we quantitatively compare the spectral properties of S-, Sq-, Q- and V-type NEOs with the spectral properties of the meteorites in the H, L, LL and HED meteorite classes. For each NEO spectrum, we assign a set of probabilities for it being related to each of these meteorite classes. Our NEO- meteorite correlation probabilities are then convolved with NEO-source region probabilities to yield a final set of meteorite-source region correlations. An apparent (significant at the 2.1-sigma level) source region signature is found for the H chondrites to be preferentially delivered to the inner solar system through the 3:1 mean motion resonance. A 3:1 resonance H chondrite source region is consistent with the short cosmic ray exposure ages known for H chondrites. The spectroscopy of asteroids is subject to several sources of inherent error. The source region model used a variety of S-type spectra without

  16. Reverse Asteroids: Searching for an Effective Tool to Combat Asteroid Belt Misconceptions

    Science.gov (United States)

    Summers, F.; Eisenhamer, B.

    2014-12-01

    The public 'knows' that asteroid belts are densely packed and dangerous for spaceships to cross. Visuals from "Star Wars" to, unfortunately, the recent "Cosmos" TV series have firmly established this astronomical misconception. However, even scientifically correct graphics, such as the Minor Planet Center's plot of the inner solar system, reinforces that view. Each pixel in the image is more than a million kilometers in width, making an accurate representation of the object density impossible.To address this widespread misconception, we are investigating an educational exercise built around a computer interactive that we call "Reverse Asteroids". In the arcade classic video game, the asteroids came to the player's spaceship. For our reverse implementation, we consider an inquiry-based activity in which the spaceship must go hunting for the asteroids, using a database of real objects in our solar system. Both 3D data visualization and basic statistical analysis play crucial roles in bringing out the true space density within the asteroid belt, and perhaps a reconciliation between imagination and reality. We also emphasize that a partnership of scientists and educators is fundamental to the success of such projects.

  17. Cratering statistics on asteroids: Methods and perspectives

    Science.gov (United States)

    Chapman, C.

    2014-07-01

    Crater size-frequency distributions (SFDs) on the surfaces of solid-surfaced bodies in the solar system have provided valuable insights about planetary surface processes and about impactor populations since the first spacecraft images were obtained in the 1960s. They can be used to determine relative age differences between surficial units, to obtain absolute model ages if the impactor flux and scaling laws are understood, to assess various endogenic planetary or asteroidal processes that degrade craters or resurface units, as well as assess changes in impactor populations across the solar system and/or with time. The first asteroid SFDs were measured from Galileo images of Gaspra and Ida (cf., Chapman 2002). Despite the superficial simplicity of these studies, they are fraught with many difficulties, including confusion by secondary and/or endogenic cratering and poorly understood aspects of varying target properties (including regoliths, ejecta blankets, and nearly-zero-g rubble piles), widely varying attributes of impactors, and a host of methodological problems including recognizability of degraded craters, which is affected by illumination angle and by the ''personal equations'' of analysts. Indeed, controlled studies (Robbins et al. 2014) demonstrate crater-density differences of a factor of two or more between experienced crater counters. These inherent difficulties have been especially apparent in divergent results for Vesta from different members of the Dawn Science Team (cf. Russell et al. 2013). Indeed, they have been exacerbated by misuse of a widely available tool (Craterstats: hrscview.fu- berlin.de/craterstats.html), which incorrectly computes error bars for proper interpretation of cumulative SFDs, resulting in derived model ages specified to three significant figures and interpretations of statistically insignificant kinks. They are further exacerbated, and for other small-body crater SFDs analyzed by the Berlin group, by stubbornly adopting

  18. Application of photometric models to asteroids

    International Nuclear Information System (INIS)

    Bowell, E.; Dominque, D.; Hapke, B.

    1989-01-01

    The way an asteroid or other atmosphereless solar system body varies in brightness in response to changing illumination and viewing geometry depends in a very complicated way on the physical and optical properties of its surface and on its overall shape. The authors summarize the formulation and application of recent photometric models by Hapke and by Lumme and Bowell. In both models, the brightness of a rough and porous surface is parametrized in terms of the optical properties of individual particles, by shadowing between particles, and by the way in which light scattered among collections of particles. Both models succeed in their goal of fitting the observed photometric behavior of a wide variety of bodies, but neither has led to a very complete understanding of the properties of asteroid regoliths, primarily because in most cases the parameters in the present models cannot be adequately constrained by observations of integral brightness alone over a restricted range of phase angles

  19. The Bering small vehicle asteroid mission concept

    DEFF Research Database (Denmark)

    Michelsen, Rene; Andersen, Anja; Haack, Henning

    2004-01-01

    targets. The dilemma obviously being the resolution versus distance and the statistics versus DeltaV requirements. Using advanced instrumentation and onboard autonomy, we have developed a space mission concept whose goal is to map the flux, size, and taxonomy distributions of asteroids. The main focus....... Although the telescope based research offers precise orbital information, it is limited to the brighter, larger objects, and taxonomy as well as morphology resolution is limited. Conversely, dedicated missions offer detailed surface mapping in radar, visual, and prompt gamma, but only for a few selected......The study of asteroids is traditionally performed by means of large Earth based telescopes, by means of which orbital elements and spectral properties are acquired. Space borne research, has so far been limited to a few occasional flybys and a couple of dedicated flights to a single selected target...

  20. Computation of Asteroid Proper Elements: Recent Advances

    Science.gov (United States)

    Knežević, Z.

    2017-12-01

    The recent advances in computation of asteroid proper elements are briefly reviewed. Although not representing real breakthroughs in computation and stability assessment of proper elements, these advances can still be considered as important improvements offering solutions to some practical problems encountered in the past. The problem of getting unrealistic values of perihelion frequency for very low eccentricity orbits is solved by computing frequencies using the frequency-modified Fourier transform. The synthetic resonant proper elements adjusted to a given secular resonance helped to prove the existence of Astraea asteroid family. The preliminary assessment of stability with time of proper elements computed by means of the analytical theory provides a good indication of their poorer performance with respect to their synthetic counterparts, and advocates in favor of ceasing their regular maintenance; the final decision should, however, be taken on the basis of more comprehensive and reliable direct estimate of their individual and sample average deviations from constancy.

  1. Heavy Metal - Exploring a magnetised metallic asteroid

    Science.gov (United States)

    Wahlund, J.-E.; Andrews, D. J.

    2017-09-01

    We propose an ESA/M5 spacecraft mission to orbit and explore (16) Psyche - the largest M-class metallic asteroid in the main belt. Recent estimates of the shape, 279×232×189 km and mass, 2.7×1019 kg of (16) Psyche make it one of the largest and densest of asteroids, 4.5 g cm-3, and together with the high surface radar reflectivity and the spectral data measured from Earth it is consistent with a bulk composition rich in iron-nickel. (16) Psyche orbits the Sun with semi-major axis 2.9 AU, 3º inclination, and is as yet unexplored in-situ.

  2. Asteroids - the modern challenge of celestial dynamics

    Science.gov (United States)

    Dikova, Smiliana

    2002-11-01

    Among the most powerful statements in Science are those that mark absolute limits to knowledge. For example, Relativity and Quantum Theory touched the limits of speed and accuracy. Deterministic Chaos - the new scientific paradigma of our days, also falls in this class theories. Chaos means complexity in space and unpredictability in time. It shows the limit of our basic counting system and leads to a limited predictability of the long time dynamical evolution. Perhaps for that reason, in 1986 Sir James Lighthill remarked for all physicists: "We collectively wish to apologize for having misled the general educated public by spreading ideas about the determinism of systems satisfying Newton's laws of motion that, after 1960, were proved incorrect." Our main thesis is that Asteroid Dynamics is the arena where the drama Chaos versus predictability is initiated and developed. The aim of the present research is to show the way in which Deterministic Chaos restricts the long term dynamical predictability of asteroid motions.

  3. WEED CONTROL EFFECTS ON SOIL CHEMICAL CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    Paulo Sérgio Lima e Silva

    2008-01-01

    Full Text Available The weed control procedures are known to affect the soil physical attributes and the nutrient amount taken up by weed roots. This work hypothesis is that weed control methods might also affect soil chemical attributes. Four experiments were carried out, three with maize (E-1, E-2 and E-3 and one with cotton (E-4, in randomized complete blocks design arranged in split-plots, with five replications. In E-1 experiment, the plots consisted of two weed control treatments: no-weed control and weed shovel-digging at 20 and 40 days after sowing; and the subplots consisted of six maize cultivars. In the three other experiments, the plots consisted of plant cultivars: four maize cultivars (E-2 and E-3 and four cotton cultivars (E-4. And, the subplots consisted of three weed control treatments: (1 no-weed control; (2 weed shovel-digging at 20 and 40 days after sowing; and (3 intercropping with cowpea (E-2 or Gliricidia sepium (Jacq. Walp. (E-3 and E-4. In all experiments, after harvest, eight soil samples were collected from each subplot (0-20 cm depth and composed in one sample. Soil chemical analysis results indicated that the weed control by shovel-digging or intercropping may increase or decrease some soil element concentrations and the alterations depend on the element and experiment considered. In E-2, the weed shovel-dug plots showed intermediate soil pH, lower S (sum of bases values and higher soil P concentrations than the other plots. In E-4, soil K and Na concentrations in plots without weed control did not differ from plots with intercropping, and in both, K and Na values were higher than in weed shovel-dug plots. Maize and cotton cultivars did not affect soil chemical characteristics.

  4. SEM and TEM Observation of the Surfaces of the Fine-Grained Particles Retrieved from the Muses-C Regio on the Asteroid 25413 Itokawa

    Science.gov (United States)

    Noguchi, T.; Nakamura, T.; Zolensky, Michael E.; Tanaka, M.; Hashimoto, T.; Konno, M.; Nakato, A.; Ogami, T.; Fujimura, A.; Abe, M.; hide

    2011-01-01

    Surface materials on airless solar system bodies exposed to interplanetary space are gradually changed their visible to near-infrared reflectance spectra by the process called "space weathering", which makes the spectra darker and redder. Hapke et al. proposed a model of space weathering: vapor deposition of nanophase reduced iron (npFe(sup 0)) on the surfaces of the grains within the very surface of lunar regolith. This model has been proved by detailed observation of the surfaces of the lunar soil grains by transmission electron microscope (TEM). They demonstrated that npFe(sup 0) was formed by a combination of vapor deposition and irradiation effects. In other words, both micrometeorite impacts and irradiation by solar wind and galactic cosmic ray play roles on the space weathering on the Moon. Because there is a continuum of reflectance spectra from those of Q-type asteroids (almost the same as those of ordinary chondrites) to those of S-type asteroids, it is strongly suggested that reflectance spectra of asteroids composed of ordinary chondrite-like materials were modified over time to those of S-type asteroids due to space weathering. It is predicted that a small amount of npFe(sup 0) on the surface of grains in the asteroidal regolith composed of ordinary chondrite-like materials is the main agent of asteroidal space weathering.

  5. Formation and Evolution of Binary Asteroids

    Science.gov (United States)

    Walsh, K. J.; Jacobson, S. A.

    Satellites of asteroids have been discovered in nearly every known small-body population, and a remarkable aspect of the known satellites is the diversity of their properties. They tell a story of vast differences in formation and evolution mechanisms that act as a function of size, distance from the Sun, and the properties of their nebular environment at the beginning of solar system history and their dynamical environment over the next 4.5 G.y. The mere existence of these systems provides a laboratory to study numerous types of physical processes acting on asteroids, and their dynamics provide a valuable probe of their physical properties otherwise possible only with spacecraft. Advances in understanding the formation and evolution of binary systems have been assisted by (1) the growing catalog of known systems, increasing from 33 to ~250 between the Merline et al. (2002) chapter in Asteroids III and now; (2) the detailed study and long-term monitoring of individual systems such as 1999 KW4 and 1996 FG3, (3) the discovery of new binary system morphologies and triple systems, (4) and the discovery of unbound systems that appear to be end-states of binary dynamical evolutionary paths. Specifically for small bodies (diameter smaller than 10 km), these observations and discoveries have motivated theoretical work finding that thermal forces can efficiently drive the rotational disruption of small asteroids. Long-term monitoring has allowed studies to constrain the system's dynamical evolution by the combination of tides, thermal forces, and rigid-body physics. The outliers and split pairs have pushed the theoretical work to explore a wide range of evolutionary end-states.

  6. Consequences of Predicted or Actual Asteroid Impacts

    Science.gov (United States)

    Chapman, C. R.

    2003-12-01

    Earth impact by an asteroid could have enormous physical and environmental consequences. Impactors larger than 2 km diameter could be so destructive as to threaten civilization. Since such events greatly exceed any other natural or man-made catastrophe, much extrapolation is necessary just to understand environmental implications (e.g. sudden global cooling, tsunami magnitude, toxic effects). Responses of vital elements of the ecosystem (e.g. agriculture) and of human society to such an impact are conjectural. For instance, response to the Blackout of 2003 was restrained, but response to 9/11 terrorism was arguably exaggerated and dysfunctional; would society be fragile or robust in the face of global catastrophe? Even small impacts, or predictions of impacts (accurate or faulty), could generate disproportionate responses, especially if news media reports are hyped or inaccurate or if responsible entities (e.g. military organizations in regions of conflict) are inadequately aware of the phenomenology of small impacts. Asteroid impact is the one geophysical hazard of high potential consequence with which we, fortunately, have essentially no historical experience. It is thus important that decision makers familiarize themselves with the hazard and that society (perhaps using a formal procedure, like a National Academy of Sciences study) evaluate the priority of addressing the hazard by (a) further telescopic searches for dangerous but still-undiscovered asteroids and (b) development of mitigation strategies (including deflection of an oncoming asteroid and on- Earth civil defense). I exemplify these issues by discussing several representative cases that span the range of parameters. Many of the specific physical consequences of impact involve effects like those of other geophysical disasters (flood, fire, earthquake, etc.), but the psychological and sociological aspects of predicted and actual impacts are distinctive. Standard economic cost/benefit analyses may not

  7. Formation of asteroid pairs by rotational fission

    Czech Academy of Sciences Publication Activity Database

    Pravec, Petr; Vokrouhlický, D.; Polishook, D.; Scheeres, D.J.; Harris, A. W.; Galád, Adrián; Vaduvescu, O.; Pozo, F.; Barr, A.; Longa, P.; Vachier, F.; Colas, F.; Pray, D. P.; Pollock, J.; Reichart, D. E.; Ivarsen, K.M.; Haislip, J.B.; LaCluyze, A.; Kušnirák, Peter; Henych, Tomáš; Marchis, F.; Macomber, B.; Jacobson, S.A.; Krugly, Yu. N.; Sergeev, A.V.; Leroy, A.

    2010-01-01

    Roč. 466, č. 7310 (2010), s. 1085-1088 ISSN 0028-0836 R&D Projects: GA ČR GA205/09/1107; GA ČR GD205/08/H005 Institutional research plan: CEZ:AV0Z10030501 Keywords : full 2-body problem * binary asteroids * stability Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 36.101, year: 2010

  8. Dynamical portrait of the Hoffmeister asteroid family

    Science.gov (United States)

    Novakovic, Bojan; Maurel, Clara; Tsirvoulis, Georgios; Knezevic, Zoran; Radovic, Viktor

    2015-08-01

    The (1726) Hoffmeister asteroid family is located in the middle of the Main Belt, between 2.75 and 2.82 AU. It draws our attention due to its unusual shape when projected to the semi-major axis vs. inclination plane. Actually, the distribution of family members as seen in this plane clearly suggests different dynamical evolution for the two parts of the family delimited in terms of semi-major axis.Therefore, we investigate here the dynamics of the family members aiming primarily to explain the observed unusual shape, but we also reconstruct the evolution of the whole family in time, and estimated its age.The Hoffmeister family is close to the fourth degree secular resonance z1=g-g6+s-s6, and in the neighborhood of the most massive asteroid (1) Ceres, each of these possibly being responsible for the strange shape of the family. To identify which ones, if any, among the different possible dynamical mechanisms are actually at work here, we performed a set of numerical integrations. We integrate the orbits of test particles over 300 Myr, as the age of the Hoffmeister family was previously roughly estimated to be 300 ± 200 Myr. Moreover, in order to identify and isolate the main perturber(s), we repeat four times the integrations using each time a different dynamical model, taking or not into account the Yarkovsky effect and dwarf planet Ceres as a perturbing body.Our results reveal the significant role of a so far overlooked dynamical aspect, namely a secular resonance between the dwarf planet Ceres and other asteroids. In particular, we show that the post-impact evolution of the Hoffmeister asteroid family is a direct consequence of the nodal secular resonance with Ceres.

  9. Alien Asteroid Belt Compared to our Own

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1: Band of Light Comparison This artist's concept illustrates what the night sky might look like from a hypothetical alien planet in a star system with an asteroid belt 25 times as massive as the one in our own solar system (alien system above, ours below; see Figure 1). NASA's Spitzer Space Telescope found evidence for such a belt around the nearby star called HD 69830, when its infrared eyes spotted dust, presumably from asteroids banging together. The telescope did not find any evidence for a planet in the system, but astronomers speculate one or more may be present. The movie begins at dusk on the imaginary world, when HD 69830, like our Sun, has begun to set over the horizon. Time is sped up to show the onset of night and the appearance of a brilliant band of light. This light comes from dust in a massive asteroid belt, which scatters sunlight. In our solar system, anybody observing the skies on a moonless night far from city lights can see the sunlight that is scattered by dust in our asteroid belt. Called zodiacal light and sometimes the 'false dawn,' this light appears as a dim band stretching up from the horizon when the Sun is about to rise or set. The light is faint enough that the disk of our Milky Way galaxy remains the most prominent feature in the sky. (The Milky Way disk is shown perpendicular to the zodiacal light in both pictures.) In contrast, the zodiacal light in the HD 69830 system would be 1,000 times brighter than our own, outshining even the Milky Way.

  10. ASTEROID SIZING BY RADIOGALAXY OCCULTATION AT 5 GHZ

    Energy Technology Data Exchange (ETDEWEB)

    Lehtinen, K.; Muinonen, K.; Poutanen, M. [Finnish Geospatial Research Institute FGI, Geodeetinrinne 2, FI-02430 Masala (Finland); Bach, U. [Max-Planck-Institut für Radioastronomie, Radioobservatorium Effelsberg, Max-Planck-Str. 28, D-53902 Bad Münstereifel-Effelsberg (Germany); Petrov, L., E-mail: kimmo.lehtinen@nls.fi [Astrogeo Center, Falls Church, VA 22043 (United States)

    2016-05-10

    Stellar occultations by asteroids observed at visual wavelengths have been an important tool for studying the size and shape of asteroids and for revising the orbital parameters of asteroids. At radio frequencies, a shadow of an asteroid on the Earth is dominated by diffraction effects. Here, we show, for the first time, that a single observation of an occultation of a compact radio source at a frequency of 5 GHz can be used to derive the effective size of the occulting object and to derive the distance between the observer and the center of the occultation path on the Earth. The derived diameter of the occulting object, asteroid (115) Thyra, is 75 ± 6 km. The observed occultation profile shows features that cannot be explained by diffraction of a single asteroid.

  11. The comet rendezvous asteroid flyby mission

    International Nuclear Information System (INIS)

    Morrison, D.; Neugebauer, M.; Weissman, P.R.

    1989-01-01

    The Comet Rendezvous Asteroid Flyby (CRAF) mission is designed to answer the many questions raised by the Halley missions by exploring a cometary nucleus in detail, following it around its orbit and studying its changing activity as it moves closer to and then away from the Sun. In addition, on its way to rendezvous with the comet, CRAF will fly by a large, primitive class main belt asteroid and will return valuable data for comparison with the comet results. The selected asteroid is 449 Hamburga with a diameter of 88 km and a surface composition of carbonaceous chondrite meteorites. The expected flyby date is January, 1998. The CRAF spacecraft will continue to make measurements in orbit around the cometary nucleus as they both move closer to the Sun, until the dust and gas hazard becomes unsafe. At that point the spacecraft will move in and out between 50 and 2,500 kilometers to study the inner coma and the cometary ionosphere, and to collect dust and gas samples for onboard analysis. Following perihelion, the spacecraft will make a 50,000 km excursion down the comet's tail, further investigating the solar wind interaction with the cometary atmosphere. The spacecraft will return to the vicinity of the nucleus about four months after perihelion to observe the changes that have taken place. If the spacecraft remains healthy and adequate fuel is still onboard, an extended mission to follow the comet nucleus out to aphelion is anticipated

  12. Progress in clinical research of asteroid hyalosis

    Directory of Open Access Journals (Sweden)

    Xiao-Xue Liu

    2017-08-01

    Full Text Available Asteroid Hyalosis(AHis a common clinical disease, which has been considered a benign disorder as it rarely impairs visual acuity. It was often discovered when the patient was treated for other eye diseases. The mechanism was unclear. Its characteristic B-ultrasound property makes the B-ultrasound a very helpful diagnostic technique. In the case of the patients with other fundus diseases associated with AH, optical coherence tomography(OCTand fluorescein angiography(FAmay be used to reduce the interference from asteroid bodies, therefore improve the fundus visibility. Recent studies have shown that AH can incorporate with many other eye diseases. For example, in patients with cataracts, asteroid hyalosis can cause surface calcification of silicone plate intraocular lenses, which in most cases may lead to the need for explantation of the calcified intraocular lenses. The efficacy of pars plana vitrectomy(PPV, the removal of some, or all, of the eye's vitreous humor for AH remains controversial. In this paper, we provide a review of the recent literature on AH disease: the etiology, diagnosis and treatment. We hope to thus improve the awareness and outcomes of AH disease.

  13. A Probabilistic Asteroid Impact Risk Model

    Science.gov (United States)

    Mathias, Donovan L.; Wheeler, Lorien F.; Dotson, Jessie L.

    2016-01-01

    Asteroid threat assessment requires the quantification of both the impact likelihood and resulting consequence across the range of possible events. This paper presents a probabilistic asteroid impact risk (PAIR) assessment model developed for this purpose. The model incorporates published impact frequency rates with state-of-the-art consequence assessment tools, applied within a Monte Carlo framework that generates sets of impact scenarios from uncertain parameter distributions. Explicit treatment of atmospheric entry is included to produce energy deposition rates that account for the effects of thermal ablation and object fragmentation. These energy deposition rates are used to model the resulting ground damage, and affected populations are computed for the sampled impact locations. The results for each scenario are aggregated into a distribution of potential outcomes that reflect the range of uncertain impact parameters, population densities, and strike probabilities. As an illustration of the utility of the PAIR model, the results are used to address the question of what minimum size asteroid constitutes a threat to the population. To answer this question, complete distributions of results are combined with a hypothetical risk tolerance posture to provide the minimum size, given sets of initial assumptions. Model outputs demonstrate how such questions can be answered and provide a means for interpreting the effect that input assumptions and uncertainty can have on final risk-based decisions. Model results can be used to prioritize investments to gain knowledge in critical areas or, conversely, to identify areas where additional data has little effect on the metrics of interest.

  14. Asteroids in the High Cadence Transient Survey

    Science.gov (United States)

    Peña, J.; Fuentes, C.; Förster, F.; Maureira, J. C.; San Martín, J.; Littín, J.; Huijse, P.; Cabrera-Vives, G.; Estévez, P. A.; Galbany, L.; González-Gaitán, S.; Martínez, J.; de Jaeger, Th.; Hamuy, M.

    2018-03-01

    We report on the serendipitous observations of solar system objects imaged during the High cadence Transient Survey 2014 observation campaign. Data from this high-cadence wide-field survey was originally analyzed for finding variable static sources using machine learning to select the most-likely candidates. In this work, we search for moving transients consistent with solar system objects and derive their orbital parameters. We use a simple, custom motion detection algorithm to link trajectories and assume Keplerian motion to derive the asteroid’s orbital parameters. We use known asteroids from the Minor Planet Center database to assess the detection efficiency of the survey and our search algorithm. Trajectories have an average of nine detections spread over two days, and our fit yields typical errors of {σ }a∼ 0.07 {au}, σ e ∼ 0.07 and σ i ∼ 0.°5 in semimajor axis, eccentricity, and inclination, respectively, for known asteroids in our sample. We extract 7700 orbits from our trajectories, identifying 19 near-Earth objects, 6687 asteroids, 14 Centaurs, and 15 trans-Neptunian objects. This highlights the complementarity of supernova wide-field surveys for solar system research and the significance of machine learning to clean data of false detections. It is a good example of the data-driven science that Large Synoptic Survey Telescope will deliver.

  15. DISINTEGRATING ASTEROID P/2013 R3

    Energy Technology Data Exchange (ETDEWEB)

    Jewitt, David; Li, Jing [Department of Earth, Planetary and Space Sciences, UCLA, 595 Charles Young Drive East, Los Angeles, CA 90095-1567 (United States); Agarwal, Jessica [Max Planck Institute for Solar System Research, Max-Planck-Str. 2, D-37191 Katlenburg-Lindau (Germany); Weaver, Harold [The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Mutchler, Max [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Larson, Stephen, E-mail: jewitt@ucla.edu [Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Boulevard, Tucson, AZ 85721-0092 (United States)

    2014-03-20

    Splitting of the nuclei of comets into multiple components has been frequently observed but, to date, no main-belt asteroid has been observed to break up. Using the Hubble Space Telescope, we find that main-belt asteroid P/2013 R3 consists of 10 or more distinct components, the largest up to 200 m in radius (assumed geometric albedo of 0.05) each of which produces a coma and comet-like dust tail. A diffuse debris cloud with total mass ∼2 × 10{sup 8} kg further envelopes the entire system. The velocity dispersion among the components, ΔV ∼ 0.2-0.5 m s{sup –1}, is comparable to the gravitational escape speeds of the largest members, while their extrapolated plane-of-sky motions suggest a break up between 2013 February and September. The broadband optical colors are those of a C-type asteroid. We find no spectral evidence for gaseous emission, placing model-dependent upper limits to the water production rate ≤1 kg s{sup –1}. Breakup may be due to a rotationally induced structural failure of the precursor body.

  16. Naming asteroids for the popularisation of astronomy

    Science.gov (United States)

    Naranjo, O. A.

    2008-06-01

    We give a detailed description of how the naming of asteroids was used as a prize in competitions run by educational institutions and museums. There were two events, one in Venezuela and one in Brazil, which used this as an attractive alternative method for the popularisation of astronomy. The first competition, named Bautizo Espacial (Space Baptism), consisted of scientific stories written by high school students. The second, called Grande Desafio (Big Challenge), was a competition where teams of students were challenged to design and build prototype equipment to fight forest fires. Nationally, both events received wide publicity through newspapers, radio, TV and web pages, reaching many people in both countries. As part of both the events, several activities promoting the public knowledge of astronomy were held. The asteroids that were named in these competitions are just some of the many discovered in a search programme developed by the Group of Theoretical Astrophysics of University of Los Andes in Mérida, Venezuela (Grupo de Astrofisica Teórica de la Universidad de Los Andes) as a mainstream research programme. Finally, Asteroids for the Popularisation of Astronomy has been formally proposed to the IAU as a worldwide programme during the celebration of the International Year of Astronomy in 2009 (IYA2009).

  17. Asteroid Lightcurves from Xingming Observatory: 2017 - 2017 June

    Science.gov (United States)

    Tan, Hanjie; Yeh, Tingshuo; Li, Bin; Gao, Xing

    2018-01-01

    The lightcurves of main-belt asteroids 963, 1025, 2019, and 17814 and near-Earth asteroids (NEAs) 459872, 2014 JO25, and 2017 BS32 were obtained using Xingming Observatory (Code C42) from 2016 March to 2017 March. The absolute magnitudes of these asteroids range from H = 11.6 to 27.3, corresponding to a diameter range of 14 m to 14 km. The derived synodic rotation periods range between 0.1 to 10 h.

  18. Methods of determination of periods in the motion of asteroids

    Science.gov (United States)

    Bien, R.; Schubart, J.

    Numerical techniques for the analysis of fundamental periods in asteroidal motion are evaluated. The specific techniques evaluated were: the periodogram analysis procedure of Wundt (1980); Stumpff's (1937) system of algebraic transformations; and Labrouste's procedure. It is shown that the Labrouste procedure permitted sufficient isolation of single oscillations from the quasi-periodic process of asteroidal motion. The procedure was applied to the analysis of resonance in the motion of Trojan-type and Hilda-type asteroids, and some preliminary results are discussed.

  19. Example Solar Electric Propulsion System asteroid tours using variational calculus

    Science.gov (United States)

    Burrows, R. R.

    1985-01-01

    Exploration of the asteroid belt with a vehicle utilizing a Solar Electric Propulsion System has been proposed in past studies. Some of those studies illustrated multiple asteroid rendezvous with trajectories obtained using approximate methods. Most of the inadequacies of those approximations are overcome in this paper, which uses the calculus of variations to calculate the trajectories and associated payloads of four asteroid tours. The modeling, equations, and solution techniques are discussed, followed by a presentation of the results.

  20. Antimatter applied for Earth protection from asteroid collision

    Science.gov (United States)

    Satori, Shin; Kuninaka, Hitoshi; Kuriki, Kyoichi

    1990-01-01

    An Earth protection system against asteroids and meteorites in colliding orbit is proposed. The system consists of detection and deorbiting systems. Analyses are given for the resolution of microwave optics, the detectability of radar, the orbital plan of intercepting operation, and the antimatter mass require for totally or partially blasting the asteroid. Antimatter of 1 kg is required for deorbiting an asteroid 200 m in diameter. An experimental simulation of antimatter cooling and storage is planned. The facility under construction is discussed.

  1. Anchoring a lander on an asteroid using foam stabilization, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA has proposed several missions to land a craft on an asteroid and potentially to return samples from it. While large asteroids in the asteroid belt can exhibit a...

  2. The new NISSAN V8 gasoline engine with VVEL and DIG

    Energy Technology Data Exchange (ETDEWEB)

    Ando, Shosaku; Chujo, Keisuke [Nissan Motor Co., Ltd., Kanagawa (Japan)

    2010-07-01

    This paper describes the new 5.6-Liter V8 engine, which has been developed for use in Nissan and Infiniti full-size SUV's with the purpose of achieving excellent performance while responding to the growing environmental requirements of lower fuel consumption and lower emissions. To achieve higher full load performance, lower fuel consumption under partial load operation and lower exhaust gas emissions at cold start operation; Continuous Variable Valve Event and Lift (VVEL) and Direct Injection Gasoline (DIG) are employed as key technologies. Concerning DIG combustion concept, a wall-guided concept with side spray was finally selected for this engine rather than a spray-guided concept with centre spray in order to obtain high volumetric efficiency in natural aspiration. CFD was fully used for not only air flow, but also for fuel dynamic behaviour to analyze mixture formation in detail. The optimized intake port, piston crown shape and combustion chamber with masking shape especially realized homogeneous combustion. The concrete key factors are higher flow rate coefficient and tumble ratio for both partial load with lower valve lift and full load conditions. Thus homogeneity of mixture for anti-knocking capability at low valve lift and higher flow coefficient at WOT were developed and confirmed. Also, stratified charge combustion enables ignition timing retard and lean Air / Fuel ratio, which improves the catalyst warm up and HC gas emission after engine start. On top of the higher DIG thermal efficiency, the VVEL system which is carried over from the VK50VE and VQ37VHR engines, improves fuel consumption at partial loads by reducing pumping loss. This paper describes details of this new engine as well as highlights of the applied technologies and development procedures which have contributed to the highly balanced performances of the engine. (orig.)

  3. Dynamic wind turbine models in power system simulation tool DIgSILENT

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, A.C.; Jauch, C.; Soerensen, P.; Iov, F.; Blaabjerg, F.

    2003-12-01

    The present report describes the dynamic wind turbine models implemented in the power system simulation tool DIgSILENT (Version 12.0). The developed models are a part of the results of a national research project, whose overall objective is to create a model database in different simulation tools. This model database should be able to support the analysis of the interaction between the mechanical structure of the wind turbine and the electrical grid during different operational modes. The report provides a description of the wind turbines modelling, both at a component level and at a system level. The report contains both the description of DIgSILENT built-in models for the electrical components of a grid connected wind turbine (e.g. induction generators, power converters, transformers) and the models developed by the user, in the dynamic simulation language DSL of DIgSILENT, for the non-electrical components of the wind turbine (wind model, aerodynamic model, mechanical model). The initialisation issues on the wind turbine models into the power system simulation are also presented. However, the main attention in this report is drawn to the modelling at the system level of two wind turbine concepts: 1. Active stall wind turbine with induction generator 2. Variable speed, variable pitch wind turbine with doubly fed induction generator. These wind turbine concept models can be used and even extended for the study of different aspects, e.g. the assessment of power quality, control strategies, connection of the wind turbine at different types of grid and storage systems. For both these two concepts, control strategies are developed and implemented, their performance assessed and discussed by means of simulations. (au)

  4. THE ORIGIN OF ASTEROID 162173 (1999 JU3)

    International Nuclear Information System (INIS)

    Campins, Humberto; De León, Julia; Morbidelli, Alessandro; Gayon-Markt, Julie; Delbo, Marco; Michel, Patrick; Licandro, Javier

    2013-01-01

    Near-Earth asteroid (162173) 1999 JU 3 (henceforth JU 3 ) is a potentially hazardous asteroid and the target of the Japanese Aerospace Exploration Agency's Hayabusa-2 sample return mission. JU 3 is also a backup target for two other sample return missions: NASA's OSIRIS-REx and the European Space Agency's Marco Polo-R. We use dynamical information to identify an inner-belt, low-inclination origin through the ν 6 resonance, more specifically, the region with 2.15 AU 3 is 0.07 ± 0.01, and this inner-belt region contains four well-defined low-albedo asteroid families (Clarissa, Erigone, Polana, and Sulamitis), plus a recently identified background population of low-albedo asteroids outside these families. Only two of these five groups, the background and the Polana family, deliver JU 3 -sized asteroids to the ν 6 resonance, and the background delivers significantly more JU 3 -sized asteroids. The available spectral evidence is also diagnostic; the visible and near-infrared spectra of JU 3 indicate it is a C-type asteroid, which is compatible with members of the background, but not with the Polana family because it contains primarily B-type asteroids. Hence, this background population of low-albedo asteroids is the most likely source of JU 3

  5. SUBMILLIMETER LIGHTCURVES OF ASTEROIDS V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — Submillimeter lightcurves of large asteroids Ceres, Davida, Io, Juno, Pallas, Vesta, and Victoria, observed at the Heinrich-Hertz Submillimeter Telescope from...

  6. Photometric geodesy of main-belt asteroids. III. Additional lightcurves

    International Nuclear Information System (INIS)

    Weidenschilling, S.J.; Chapman, C.R.; Davis, D.R.; Greenberg, R.; Levy, D.H.

    1990-01-01

    A total of 107 complete or partial lightcurves are presented for 59 different asteroids over the 1982-1989 period. Unusual lightcurves with unequal minima and maxima at large amplitudes are preferentially seen for M-type asteroids. Some asteroids, such as 16 Psyche and 201 Penelope, exhibit lightcurves combining large amplitude with very unequal brightness for both maxima and both minima, even at small phase angles. An M-type asteroid is believed to consist of a metal core of a differentiated parent body that has had its rocky mantle completely removed by one or more large impacts. 39 refs

  7. The Nature of C Asteroid Regolith from Meteorite Observations

    Science.gov (United States)

    Zolensky, M.; Mikouchi, T.; Hagiya, K.; Ohsumi, K.; Komatsu, M.; Jenniskens, P.; Le, L.; Yin, Q.-Z; Kebukawa, Y.; Fries, M.

    2013-01-01

    Regolith from C (and related) asteroid bodies are a focus of the current missions Dawn at Ceres, Hayabusa 2 and OSIRIS REx. An asteroid as large as Ceres is expected to be covered by a mature regolith, and as Hayabusa demonstrated, flat and therefore engineeringly-safe ponded deposits will probably be the sampling sites for both Hayabusa 2 and OSIRIS REx. Here we examine what we have learned about the mineralogy of fine-grained asteroid regolith from recent meteorite studies and the examination of the samples harvested from asteroid Itokawa by Hayabusa.

  8. Capturing asteroids into bound orbits around the earth: Massive early return on an asteroid terminal defense system

    International Nuclear Information System (INIS)

    Hills, J.G.

    1992-01-01

    Nuclear explosives may be used to capture small asteroids (e.g., 20--50 meters in diameter) into bound orbits around the earth. The captured objects could be used for construction material for manned and unmanned activity in Earth orbit. Asteroids with small approach velocities, which are the ones most likely to have close approaches to the Earth, require the least energy for capture. They are particularly easy to capture if they pass within one Earth radius of the surface of the Earth. They could be intercepted with intercontinental missiles if the latter were retrofit with a more flexible guiding and homing capability. This asteroid capture-defense system could be implemented in a few years at low cost by using decommissioned ICMs. The economic value of even one captured asteroid is many times the initial investment. The asteroid capture system would be an essential part of the learning curve for dealing with larger asteroids that can hit the earth

  9. Application of DIgSILENT POWERFACTORY software for modeling of industrial network relay protection system

    Directory of Open Access Journals (Sweden)

    Sučević Nikola

    2016-01-01

    Full Text Available This paper presents modeling of industrial network relay protection system using DIgSILENT PowerFactory software. The basis for the model of protection system is a model of a single substation in an industrial network. The paper presents the procedure for modeling of protective devices of 6 kV asynchronous motors, 6/0,4 kV/kV transformers as well as protection in the bus coupler and busbar protection. Protective relay system response for the simulated disturbances is shown in the paper.

  10. DigDag, Digitalt atlas over Danmarks historisk-administrative geografi

    DEFF Research Database (Denmark)

    Knudsen, Bo Nissen; Gammeltoft, Peder

    2012-01-01

    Administrative geografiske enheder ses ofte som stabile over tid. Det er imidlertid ikke tilfældet. Der kan forekomme en række af rumlige, sociale – og sproglige – ændringer; eksempelvis navneskift, ændrede grænsedragninger og ændringer i den administrative struktur. Dette betyder at forskning som...... tager udgangspunkt i geografisk relaterede eller ordnede data, kan komme i problemer så snart geografien på dataindsamlingstidspunktet ikke svarer til den nuværende geografi, og den 'gamle' geografi ikke er umiddelbart til at få rede på. DigDag-projektet adresserer denne udfordring for forskere inden...

  11. Application of DIgSILENT POWERFACTORY software for modeling of industrial network relay protection system

    OpenAIRE

    Sučević Nikola; Milošević Dejan

    2016-01-01

    This paper presents modeling of industrial network relay protection system using DIgSILENT PowerFactory software. The basis for the model of protection system is a model of a single substation in an industrial network. The paper presents the procedure for modeling of protective devices of 6 kV asynchronous motors, 6/0,4 kV/kV transformers as well as protection in the bus coupler and busbar protection. Protective relay system response for the simulated disturbances is shown in the paper.

  12. Diversity and Innovation for Geosciences (dig) Texas Earth and Space Science Instructional Blueprints

    Science.gov (United States)

    Ellins, K. K.; Bohls-Graham, E.; Riggs, E. M.; Serpa, L. F.; Jacobs, B. E.; Martinez, A. O.; Fox, S.; Kent, M.; Stocks, E.; Pennington, D. D.

    2014-12-01

    The NSF-sponsored DIG Texas Instructional Blueprint project supports the development of online instructional blueprints for a yearlong high school-level Earth science course. Each blueprint stitches together three-week units that contain curated educational resources aligned with the Texas state standards for Earth and Space Science and the Earth Science Literacy Principles. Units focus on specific geoscience content, place-based concerns, features or ideas, or other specific conceptual threads. Five regional teams composed of geoscientists, pedagogy specialists, and practicing science teachers chose unit themes and resources for twenty-two units during three workshops. In summer 2014 three Education Interns (Earth science teachers) spent six weeks refining the content of the units and aligning them with the Next Generation Science Standards. They also assembled units into example blueprints. The cross-disciplinary collaboration among blueprint team members allowed them to develop knowledge in new areas and to share their own discipline-based knowledge and perspectives. Team members and Education Interns learned where to find and how to evaluate high quality geoscience educational resources, using a web-based resource review tool developed by the Science Education Resource Center (SERC). SERC is the repository for the DIG Texas blueprint web pages. Work is underway to develop automated tools to allow educators to compile resources into customized instructional blueprints by reshuffling units within an existing blueprint, by mixing units from other blueprints, or creating new units and blueprints. These innovations will enhance the use of the units by secondary Earth science educators beyond Texas. This presentation provides an overview of the project, shows examples of blueprints and units, reports on the preliminary results of classroom implementation by Earth science teachers, and considers challenges encountered in developing and testing the blueprints. The

  13. Results of performance tests on chemical and radiation measurement systems for use at a dig-face

    International Nuclear Information System (INIS)

    Gehrke, R.J.; Lawrence, R.S.; Pawelko, R.J.

    1995-04-01

    Chemical and radiation measurement systems are being developed for use at a dig-face to provide sensing capability during the excavation of previously buried waste. it is believed that on-line dig-face characterization will reduce environmental, health, and safety risks during the cleanup of buried waste sites as well as improve the efficiency of the cleanup process. This report describes progress in the development of three measurement systems: (a) a γ/neutron monitor that scans the dig-face for high levels of radiation prior to excavation, (b) a Ge spectrometer that identifies specific radionuclides located with the γ/neutron monitor, and (c) a prompt γ neutron activation analysis (PGNAA) system that measures the presence of chlorine and chlorinated compounds often associated with hazardous waste. The Ge spectrometer and PGNAA system also will provide off-line but on-site capability of radionuclide and elemental identification of excavated waste prior to handling, treatment, transportation, or disposal

  14. Asteroid mass estimation with Markov-chain Monte Carlo

    Science.gov (United States)

    Siltala, Lauri; Granvik, Mikael

    2017-10-01

    Estimates for asteroid masses are based on their gravitational perturbations on the orbits of other objects such as Mars, spacecraft, or other asteroids and/or their satellites. In the case of asteroid-asteroid perturbations, this leads to a 13-dimensional inverse problem at minimum where the aim is to derive the mass of the perturbing asteroid and six orbital elements for both the perturbing asteroid and the test asteroid by fitting their trajectories to their observed positions. The fitting has typically been carried out with linearized methods such as the least-squares method. These methods need to make certain assumptions regarding the shape of the probability distributions of the model parameters. This is problematic as these assumptions have not been validated. We have developed a new Markov-chain Monte Carlo method for mass estimation which does not require an assumption regarding the shape of the parameter distribution. Recently, we have implemented several upgrades to our MCMC method including improved schemes for handling observational errors and outlier data alongside the option to consider multiple perturbers and/or test asteroids simultaneously. These upgrades promise significantly improved results: based on two separate results for (19) Fortuna with different test asteroids we previously hypothesized that simultaneous use of both test asteroids would lead to an improved result similar to the average literature value for (19) Fortuna with substantially reduced uncertainties. Our upgraded algorithm indeed finds a result essentially equal to the literature value for this asteroid, confirming our previous hypothesis. Here we show these new results for (19) Fortuna and other example cases, and compare our results to previous estimates. Finally, we discuss our plans to improve our algorithm further, particularly in connection with Gaia.

  15. Resurfacing asteroids from YORP spin-up and failure

    Science.gov (United States)

    Graves, Kevin J.; Minton, David A.; Hirabayashi, Masatoshi; DeMeo, Francesca E.; Carry, Benoit

    2018-04-01

    The spectral properties of S and Q-type asteroids can change over time due to interaction with the solar wind and micrometeorite impacts in a process known as 'space weathering.' Space weathering raises the spectral slope and decreases the 1 μm absorption band depth in the spectra of S and Q-type asteroids. Over time, Q-type asteroids, which have very similar spectra to ordinary chondrite meteorites, will change into S-type asteroids. Because there are a significant number of Q-type asteroids, there must be some process which is resurfacing S-type asteroids into Q-types. In this study, we use asteroid data from the Sloan Digital Sky Survey to show a trend between the slope through the g‧, r‧, and i‧ filters, called the gri-slope, and size that holds for all populations of S and Q-type asteroids in the inner solar system, regardless of orbit. We model the evolution of a suite of asteroids in a Monte Carlo YORP rotational evolution and space weathering model. We show that spin-up and failure from YORP is one of the key resurfacing mechanisms that creates the observed weathering trends with size. By varying the non-dimensional YORP coefficient and running time of the present model over the range 475-1425 Myr, we find a range of values for the space weathering timescale, τSW ≈ 19-80 Myr at 2.2 AU. We also estimate the time to weather a newly resurfaced Q-type asteroid into an S-complex asteroid at 1 AU, τQ → S(1AU) ≈ 2-7 Myr.

  16. BAOBAB (Big And Outrageously Bold Asteroid Belt) Project

    Science.gov (United States)

    Mcfadden, L. A.; Thomas, C. A; Englander, J. A.; Ruesch, O.; Hosseini, S.; Goossens, S. J.; Mazarico, E. M.; Schmerr, N.

    2017-01-01

    One of the intriguing results of NASA's Dawn mission is the composition and structure of the Main Asteroid Belt's only known dwarf planet, Ceres [1]. It has a top layer of dehydrated clays and salts [2] and an icy-rocky mantle [3,4]. It is widely known that the asteroid belt failed to accrete as a planet by resonances between the Sun and Jupiter. About 20-30 asteroids >100 km diameter are probably differentiated protoplanets [5]. 1) how many more and which ones are fragments of protoplanets? 2) How many and which ones are primordial rubble piles left over from condensation of the solar nebula? 3) How would we go about gaining better and more complete characterization of the mass, interior structure and composition of the Main Belt asteroid population? 4) What is the relationship between asteroids and ocean worlds? Bulk parameters such as the mass, density, and porosity, are important to characterize the structure of any celestial body, and for asteroids in particular, they can shed light on the conditions in the early solar system. Asteroid density estimates exist but currently they are often based on assumed properties of taxonomic classes, or through astronomical survey data where interactions with asteroids are weak at best resulting in large measurement uncertainty. We only have direct density estimates from spacecraft encounters for a few asteroids at this time. Knowledge of the asteroids is significant not only to understand their role in solar system workings, but also to assess their potential as space resources, as impact hazards on Earth, or even as harboring life forms. And for the distant future, we want to know if the idea put forth in a contest sponsored by Physics Today, to surface the asteroids into highly reflecting, polished surfaces and use them as a massively segmented mirror for astrophysical exploration [6], is feasible.

  17. Bayesian modeling of the mass and density of asteroids

    Science.gov (United States)

    Dotson, Jessie L.; Mathias, Donovan

    2017-10-01

    Mass and density are two of the fundamental properties of any object. In the case of near earth asteroids, knowledge about the mass of an asteroid is essential for estimating the risk due to (potential) impact and planning possible mitigation options. The density of an asteroid can illuminate the structure of the asteroid. A low density can be indicative of a rubble pile structure whereas a higher density can imply a monolith and/or higher metal content. The damage resulting from an impact of an asteroid with Earth depends on its interior structure in addition to its total mass, and as a result, density is a key parameter to understanding the risk of asteroid impact. Unfortunately, measuring the mass and density of asteroids is challenging and often results in measurements with large uncertainties. In the absence of mass / density measurements for a specific object, understanding the range and distribution of likely values can facilitate probabilistic assessments of structure and impact risk. Hierarchical Bayesian models have recently been developed to investigate the mass - radius relationship of exoplanets (Wolfgang, Rogers & Ford 2016) and to probabilistically forecast the mass of bodies large enough to establish hydrostatic equilibrium over a range of 9 orders of magnitude in mass (from planemos to main sequence stars; Chen & Kipping 2017). Here, we extend this approach to investigate the mass and densities of asteroids. Several candidate Bayesian models are presented, and their performance is assessed relative to a synthetic asteroid population. In addition, a preliminary Bayesian model for probablistically forecasting masses and densities of asteroids is presented. The forecasting model is conditioned on existing asteroid data and includes observational errors, hyper-parameter uncertainties and intrinsic scatter.

  18. Digging deeper

    DEFF Research Database (Denmark)

    Andersen, Laura Mørch; Lund, Thomas Bøker

    attitudes towards food in general and organic production and products in particular. The data is from the Danish market for organic foods, which is one of the most mature markets in the world. The segmentation splits consumers into a positive and a non-positive half, each half consisting of three different...... segments. The estimations show that the development in general organic consumption varies between segments, and that their behaviour varies between sub markets. The positive half of the population has driven the overall growth in organic budget share at the Danish market over the period 2005 to 2007, while......The purpose of this paper is to investigate how sub markets with different degrees of maturity develop during a period of general organic growth, and how different consumer segments behave on these sub markets. The paper uses actual purchasing behaviour of six consumer segments with different...

  19. Digging Carlsberg

    DEFF Research Database (Denmark)

    Riesto, Svava

    An investigation into how industrial sites become associated with value in processses of urban redevelopment. Based on a case study of the former Carlsberg breweries in Copenhagen the thesis shows how it is possible to enhance perceptions of value of an industrial site. The thesis is a contributi...... to the heuristic framework Landscpae biography and suggests how this can be operative in urban redevelopment projects. It also offers new insights into the Carlsberg brewery site- stressing open spaces as important and possible figures for the future development fo this site....

  20. The DigCurV Curriculum Framework for Digital Curation in the Cultural Heritage Sector

    Directory of Open Access Journals (Sweden)

    Laura Molloy

    2014-07-01

    Full Text Available In 2013, the DigCurV collaborative network completed development of a Curriculum Framework for digital curation skills in the European cultural heritage sector. DigCurV synthesised a variety of established skills and competence models in the digital curation and LIS sectors with expertise from digital curation professionals, in order to develop a new Curriculum Framework. The resulting Framework provides a common language and helps define the skills, knowledge and abilities that are necessary for the development of digital curation training; for benchmarking existing programmes; and for promoting the continuing production, improvement and refinement of digital curation training programmes. This paper describes the salient points of this work, including how the project team conducted the research necessary to develop the Framework, the structure of the Framework, the processes used to validate the Framework, and three ‘lenses’ onto the Framework. The paper also provides suggestions as to how the Framework might be used, including a description of potential audiences and purposes.

  1. Attenuation Modified by DIG and Dust as Seen in M31

    Energy Technology Data Exchange (ETDEWEB)

    Tomičić, Neven; Kreckel, Kathryn; Schinnerer, Eva [Max Planck Institute for Astronomy (MPIA), Königstuhl 17, 69117 Heidelberg (Germany); Groves, Brent [School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Sandstrom, Karin [Center for Astrophysics and Space Sciences, Department of Physics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 (United States); Kapala, Maria [Department of Astronomy, University of Cape Town, Republic of South Africa (South Africa); Blanc, Guillermo A. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Leroy, Adam, E-mail: tomicic@mpia-hd.mpg.de [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)

    2017-08-01

    The spatial distribution of dust in galaxies affects the global attenuation, and hence inferred properties, of galaxies. We trace the spatial distribution of dust in five approximately kiloparsec fields of M31 by comparing optical attenuation with the total dust mass distribution. We measure the attenuation from the Balmer decrement using Integral Field Spectroscopy and the dust mass from Herschel far-IR observations. Our results show that M31's dust attenuation closely follows a foreground screen model, contrary to what was previously found in other nearby galaxies. By smoothing the M31 data, we find that spatial resolution is not the cause for this difference. Based on the emission-line ratios and two simple models, we conclude that previous models of dust/gas geometry need to include a weakly or non-attenuated diffuse ionized gas (DIG) component. Due to the variation of dust and DIG scale heights with galactic radius, we conclude that different locations in galaxies will have different vertical distributions of gas and dust and therefore different measured attenuation. The difference between our result in M31 with that found in other nearby galaxies can be explained by our fields in M31 lying at larger galactic radii than the previous studies that focused on the centers of galaxies.

  2. Reducing Digging Losses by Using Automated Steering to Plant and Invert Peanuts

    Directory of Open Access Journals (Sweden)

    George Vellidis

    2014-07-01

    Full Text Available GPS guidance of farm machinery has been increasingly adopted by farmers because of the perceived gains in efficiency that it provides. In the southeastern USA one of the reasons farmers adopt GPS guidance, and specifically automated steering (auto-steer, is that it can theoretically result in large yield gains when used to plant and invert peanuts—one of the region’s most important crops. The goal of our study was to quantify the yield benefit of using real time kinematic (RTK-based auto-steer to plant and invert peanuts under a variety of terrain conditions. Yield benefits result from reduced digging losses. The study was conducted for two consecutive years (2010 and 2011 on a private farm in Georgia, USA. When all data are grouped together, auto-steer outperformed conventional by 579 kg/ha in 2010 and 451 kg/ha in 2011. We also evaluated the performance of auto-steer under different curvature conditions using low, medium, and high curvature rows. The results showed that auto-steer outperformed conventional under all curvature by a minimum of 338 kg/ha. Finally, we evaluated passive implement guidance in combination with auto-steer and found that it holds tremendous potential for further reducing digging losses. In many cases, auto-steer will pay for itself within a year.

  3. Seven Asteroids Studied from Modra Observatory in the Course of Binary Asteroid Photometric Campaign

    Czech Academy of Sciences Publication Activity Database

    Galád, Adrián; Pravec, Petr; Kornoš, L.; Gajdoš, Š.; Világi, J.

    2007-01-01

    Roč. 101, 1-2 (2007), s. 17-25 ISSN 0167-9295 R&D Projects: GA ČR(CZ) GA205/05/0604 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroids * photometry Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.558, year: 2007

  4. Investigating the origin of the asteroids and early findings on Vesta historical studies in asteroid research

    CERN Document Server

    Cunningham, Clifford J

    2017-01-01

    This book assesses the origin of asteroids by analyzing the discovery of Vesta in 1807. Wilhelm Olbers, who discovered Vesta, suggested that the asteroids were the result of a primordial planet’s explosion. Cunningham studies that idea in detail through the writings of Sir David Brewster in Scotland, the era's most prolific writer about the asteroids. He also examines the link between meteorites and asteroids, revealing a synergy between Ernst Chladni, Romantic symbolism, and the music of the spheres. Vesta was a lightning rod for controversy throughout the nineteenth century with observers arguing over its size and color, and the astounding notion that it was self-luminous. It was also a major force for change, as new methods in the field of celestial mechanics were developed to study the orbital perturbations it is subject to. A large selection of private correspondence and scientific papers complete the first comprehensive historical study of Vesta ever published. With a synoptic look at the four astero...

  5. A SEARCH FOR ASTEROIDS, MOONS, AND RINGS ORBITING WHITE DWARFS

    International Nuclear Information System (INIS)

    Di Stefano, Rosanne; Howell, Steve B.; Kawaler, Steven D.

    2010-01-01

    Do white dwarfs host asteroid systems? Although several lines of argument suggest that white dwarfs may be orbited by large populations of asteroids, transits would provide the most direct evidence. We demonstrate that the Kepler mission has the capability to detect transits of white dwarfs by asteroids. Because white-dwarf asteroid systems, if they exist, are likely to contain many asteroids orbiting in a spatially extended distribution, discoveries of asteroid transits can be made by monitoring only a small number of white dwarfs, compatible with Kepler's primary mission, which is to monitor stars with potentially habitable planets. Possible future missions that survey 10 times as many stars with similar sensitivity and minute-cadence monitoring can establish the characteristics of asteroid systems around white dwarfs, such as the distribution of asteroid sizes and semimajor axes. Transits by planets would be more dramatic, but the probability that they will occur is lower. Ensembles of planetary moons and/or the presence of rings around planets can also produce transits detectable by Kepler. The presence of moons and rings can significantly increase the probability that Kepler will discover planets orbiting white dwarfs, even while monitoring only a small number of them.

  6. Determination of pole orientations and shapes of asteroids

    International Nuclear Information System (INIS)

    Magnusson, P.; Barucci, M.A.; Drummond, J.D.; Lumme, K.; Surdej, J.

    1989-01-01

    The principles of asteroid lightcurve inversion and the information available from photometry are reviewed. General tools as well as specific techniques for shape and pole determinations are summarized and their advantages and shortcomings are discussed. The authors present the results obtained so far in this very active field and discuss their significance in the general context of asteroid research and planetary formation

  7. Capture orbits around asteroids by hitting zero-velocity curves

    Science.gov (United States)

    Wang, Wei; Yang, Hongwei; Zhang, Wei; Ma, Guangfu

    2017-12-01

    The problem of capturing a spacecraft from a heliocentric orbit into a high parking orbit around binary asteroids is investigated in the current study. To reduce the braking Δ V, a new capture strategy takes advantage of the three-body gravity of the binary asteroid to lower the inertial energy before applying the Δ V. The framework of the circular restricted three-body problem (CR3BP) is employed for the binary asteroid system. The proposed capture strategy is based on the mechanism by which inertial energy can be decreased sharply near zero-velocity curves (ZVCs). The strategy has two steps, namely, hitting the target ZVC and raising the periapsis by a small Δ V at the apoapsis. By hitting the target ZVC, the positive inertial energy decreases and becomes negative. Using a small Δ V, the spacecraft inserts into a bounded orbit around the asteroid. In addition, a rotating mass dipole model is employed for elongated asteroids, which leads to dynamics similar to that of the CR3BP. With this approach, the proposed capture strategy can be applied to elongated asteroids. Numerical simulations validate that the proposed capture strategy is applicable for the binary asteroid 90 Antiope and the elongated asteroid 216 Kleopatra.

  8. Earth-approaching asteroids: Populations, origin, and compositional types

    Science.gov (United States)

    Shoemaker, E. M.; Helin, E. F.

    1978-01-01

    Origin, physical properties, and discovery history of smaller asteroids are reviewed. They appear to link the main belt objects, namely the comets and meteorites. Physical observations suggest that a wide variety of compositional types are represented among the near-earth asteroids; the apparent rarity of carbonaceous objects is stated.

  9. Forging Asteroid-Meteorite Relationships Through Reflectance Spectroscopy

    Science.gov (United States)

    Burbine, T. H.; Binzel, R. P.; Bus, S. J.; Buchanan, P. C.; Hinrichs, J. L.; Meibom, A.; Hiroi, T.; Sunshine, J. M.

    2000-01-01

    Near-infrared spectra were obtained for 196 asteroids as part of SMASSIR. SMASSIR focused on observing asteroids assumed to be one of the following: (1) olivine-rich, (2) objects with "Vesta-like spectra" (the "Vestoids"), and (3) postulated meteorite parent bodies.

  10. Modeling Asteroid Dynamics using AMUSE: First Test Cases

    NARCIS (Netherlands)

    Frantseva, Kateryna; Mueller, Michael; van der Tak, Floris; Helmich, Frank P.

    2015-01-01

    We are creating a dynamic model of the current asteroid population. The goal is to reproduce measured impact rates in the current Solar System, from which we'll derive delivery rates of water and organic material by tracing low-albedo C-class asteroids (using the measured albedo distribution from

  11. Delivery of organics to Mars through asteroid and comet impacts

    NARCIS (Netherlands)

    Frantseva, K.; Mueller, M.; van der Tak, F. F. S.; ten Kate, I. L.; Greenstreet, S.

    2017-01-01

    Preliminary results show that the asteroid-borne organic flux on Mars is comparable to the IPD rate; asteroids certainly cannot be neglected. Comets, on the other hand, contribute only 0.01% of the IDP-borne rate and can be neglected in the process of organic delivery to Mars.

  12. Mothe-Diniz Asteroid Dynamical Families V1.0

    Science.gov (United States)

    Mothe-Diniz, T.; Roig, F.; Carvano, J. M.

    2006-03-01

    This dataset contains an updated compilation of asteroid families and clusters, resulting from the application of the Hierarchical Clustering Method (HCM) on a set of around 120,000 asteroids with available proper elements. Whenever available, the classification in the Bus taxonomy is provided for family members, based on spectra from the SMASS, SMASS2 and S3OS2 spectroscopic surveys.

  13. Spin rate distribution of small asteroids

    Czech Academy of Sciences Publication Activity Database

    Pravec, Petr; Harris, A. W.; Vokrouhlický, D.; Warner, B. D.; Kušnirák, Peter; Hornoch, Kamil; Pray, D. P.; Higgins, D.; Oey, J.; Galád, Adrián; Gajdoš, Š.; Kornoš, L.; Világi, J.; Husárik, M.; Krugly, Yu. N.; Shevchenko, V. G.; Chiorny, V. G.; Gaftonyuk, N. M.; Cooney jr., W. R.; Gross, J.; Terrell, D.; Stephens, R.; Dyvig, R.; Reddy, V.; Ries, J.G.; Colas, F.; Lecacheux, J.; Durkee, R.; Masi, G.; Koff, R.; Goncalves, R.

    2008-01-01

    Roč. 197, č. 2 (2008), s. 497-504 ISSN 0019-1035 R&D Projects: GA ČR(CZ) GA205/05/0604 Grant - others: NASA (US) NAG5-13244; NASA (US) NNG06GI32G; VEGA(SK) 1/3074/06; VEGA(SK) 1/3067/06; VEGA(SK) 2/7009/27 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroids rotation * photometry * near-Earth objects Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.268, year: 2008

  14. Near-Earth asteroids: Metals occurrence, extraction, and fabrication

    Science.gov (United States)

    Westfall, Richard

    Near-earth asteroids occur in three principle types of orbits: Amor, Apollo, and Aten. Amor asteroids make relatively close (within 0.3 AU) approaches to the earth's orbit, but do not actually overlap it. Apollo asteroids spend most of their time outside the earth's orbital path, but at some point of close approach to the sun, they cross the orbit of the earth. Aten asteroids are those whose orbits remain inside the earth's path for the majority of their time, with semi-major axes less than 0.1 AU. Near-earth orbit asteroids include: stones, stony-irons, irons, carbonaceous, and super-carbonaceous. Metals within these asteroids include: iron, nickel, cobalt, the platinum group, aluminum, titanium, and others. Focus is on the extraction of ferrous and platinum group metals from the stony-iron asteroids, and the iron asteroids. Extraction of the metal fraction can be accomplished through the use of tunnel-boring-machines (TBM) in the case of the stony-irons. The metals within the story-iron asteroids occur as dispersed granules, which can be separated from the stony fraction through magnetic and gaseous digestion separation techniques. The metal asteroids are processes by drilling and gaseous digestion or by gaseous digestion alone. Manufacturing of structures, housings, framing networks, pressure vessels, mirrors, and other products is accomplished through the chemical vapor deposition (CVD) of metal coating on advanced composites and on the inside of contour-defining inflatables (CDI). Metal coatings on advanced composites provide: resistance to degradation in the hostile environments of space; superior optical properties; superior heat dissipation; service as wear coatings; and service as evidential coatings. Metal coatings on the inside of CDI produce metal load-bearing products. Fibers such as graphite, kevlar, glass, ceramic, metal, etc., can be incorporated in the metal coatings on the inside of CDI producing metal matrix products which exhibit high strength

  15. Science case for the Asteroid Impact Mission (AIM): A component of the Asteroid Impact & Deflection Assessment (AIDA) mission

    Czech Academy of Sciences Publication Activity Database

    Michel, P.; Cheng, A.; Kueppers, M.; Pravec, Petr; Blum, J.; Delbó, M.; Green, S.; Rosenblatt, P.; Tsiganis, K.; Vincent, J.B.; Biele, J.; Ciarletti, V.; Herique, A.; Ulamec, S.; Carnelli, I.; Galvez, A.; Benner, L. A. M.; Naidu, S.P.; Barnouin, O.; Richardson, D.C.; Rivkin, A. S.; Scheirich, Peter; Moskovitz, N.; Thirouin, A.; Schwartz, S.R.; Campo Bagatin, A.; Yu, Y.

    2016-01-01

    Roč. 57, č. 12 (2016), s. 2529-2547 ISSN 0273-1177 R&D Projects: GA ČR GA15-07193S Institutional support: RVO:67985815 Keywords : planetary defense * near- Earth asteroids * asteroid impact hazards Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 1.401, year: 2016

  16. Can Asteroid Airbursts Cause Dangerous Tsunami?.

    Energy Technology Data Exchange (ETDEWEB)

    Boslough, Mark B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-10-01

    I have performed a series of high-resolution hydrocode simulations to generate “source functions” for tsunami simulations as part of a proof-of-principle effort to determine whether or not the downward momentum from an asteroid airburst can couple energy into a dangerous tsunami in deep water. My new CTH simulations show enhanced momentum multiplication relative to a nuclear explosion of the same yield. Extensive sensitivity and convergence analyses demonstrate that results are robust and repeatable for simulations with sufficiently high resolution using adaptive mesh refinement. I have provided surface overpressure and wind velocity fields to tsunami modelers to use as time-dependent boundary conditions and to test the hypothesis that this mechanism can enhance the strength of the resulting shallow-water wave. The enhanced momentum result suggests that coupling from an over-water plume-forming airburst could be a more efficient tsunami source mechanism than a collapsing impact cavity or direct air blast alone, but not necessarily due to the originally-proposed mechanism. This result has significant implications for asteroid impact risk assessment and airburst-generated tsunami will be the focus of a NASA-sponsored workshop at the Ames Research Center next summer, with follow-on funding expected.

  17. Distant retrograde orbits and the asteroid hazard

    Science.gov (United States)

    Perozzi, Ettore; Ceccaroni, Marta; Valsecchi, Giovanni B.; Rossi, Alessandro

    2017-08-01

    Distant Retrograde Orbits (DROs) gained a novel wave of fame in space mission design because of their numerous advantages within the framework of the US plans for bringing a large asteroid sample in the vicinity of the Earth as the next target for human exploration. DROs are stable solutions of the three-body problem that can be used whenever an object, whether of natural or artificial nature, is required to remain in the neighborhood of a celestial body without being gravitationally captured by it. As such, they represent an alternative option to Halo orbits around the collinear Lagrangian points L1 and L2. Also known under other names ( e.g., quasi-satellite orbits, cis-lunar orbits, family- f orbits) these orbital configurations found interesting applications in several mission profiles, like that of a spacecraft orbiting around the small irregularly shaped satellite of Mars Phobos or the large Jovian moon Europa. In this paper a basic explanation of the DRO dynamics is presented in order to clarify some geometrical properties that characterize them. Their accessibility is then discussed from the point of view of mission analysis under different assumptions. Finally, their relevance within the framework of the present asteroid hazard protection programs is shown, stressing the significant increase in warning time they would provide in the prediction of impactors coming from the direction of the Sun.

  18. Galileo photometry of asteroid 243 Ida

    Science.gov (United States)

    Helfenstein, P.; Veverka, J.; Thomas, P.C.; Simonelli, D.P.; Klaasen, K.; Johnson, T.V.; Fanale, F.; Granahan, J.; McEwen, A.S.; Belton, M.; Chapman, C.

    1996-01-01

    Galileo imaging observations over phase angles 19.5?? to 109.8?? are combined with near-opposition Earth-based data to derive the photometric properties of Ida. To first order these properties are uniform over the surface and well modeled at ?? = 0.55 ??m by Hapke parameters ????0 = 0.22, h = 0.020, B0 = 1.5, g = -0.33, and ?? = 18?? with corresponding geometric albedo p = 0.21??0.030.01 and Bond albedo AB = 0.081??0.0170.008. Ida's photometric properties are more similar to those of "average S-asteroids" (P. Helfenstein and J. Veverka 1989, Asteroids II, Univ. of Arizona Press, Tucson) than are those of 951 Gaspra. Two primary color units are identified on Ida: Terrain A exhibits a spectrum with relatively shallower 1-??m absorption and a relatively steeper red spectral slope than average Ida, while Terrain B has a deeper 1-??m absorption and a less steep red slope. The average photometric properties of Ida and Terrain A are similar while those of Terrain B differ mostly in having a slightly higher value of ????0 (0.22 versus 0.21), suggesting that Terrain B consists of slightly brighter, more transparent regolith particles. Galileo observations of Ida's satellite Dactyl over phase angles 19.5?? to 47.6?? suggest photometric characteristics similar to those of Ida, the major difference being Dactyl's slightly lower albedo (0.20 compared to 0.21). ?? 1990 Academic Press, Inc.

  19. RGB Colors of the Jovian Trojan Asteroids

    Science.gov (United States)

    Chen, Haoyuan; Zhang, Xiaofei; University of Western Australia, Youth Astronomy Teachers' Link

    2017-10-01

    We use SPIRIT I&II telescopes which has 43cm diameter, to observe around 50 Jovian Trojan asteroids. Due to the limiting magnitude of our equipment, We only choose some bright asteriods as our targets.To testify the feasibility of using RGB Bayer filter system for research project, we use the RGB Bayer filter system instead of the Johnson-Cousins BVR filters system. Once proved, the photometry data will be significantly enlarged. More collected data can be used on scientific researches and more scholars can do relevant researches by using the RGB Bayer filter system. What we did is using a software called Astrometrica to measure the magnitude of the asteroids under RGB filter. Then we transform the RGB data to BVR data. Later on we calculate the color index by using those BVR data from our calculations. The final step to do the statistic work and make graphs, and compare it with the former research data. We are aim to find same result as the research before, or why there are differnt result.We are still in the process of handling the data, so the final result will be released at the conference. This project is based on data acquired using the SPIRIT robotic telescopes at The University of Western Australia. We gratefully acknowledge the assistance of Paul Luckas, SPIRIT Program Manager.The project is supported by The University of Western Australia, Youth Astronomy Teachers' Link.

  20. The Probable Ages of Asteroid Families

    Science.gov (United States)

    Harris, A. W.

    1993-01-01

    There has been considerable debate recently over the ages of the Hirayama families, and in particular if some of the families are very oung(u) It is a straightforward task to estimate the characteristic time of a collision between a body of a given diameter, d_o, by another body of diameter greater of equal to d_1. What is less straightforward is to estimate the critical diameter ratio, d_1/d_o, above which catastrophic disruption occurs, from which one could infer probable ages of the Hirayama families, by knowing the diameter of the parent body, d_o. One can gain some insight into the probable value of d_1/d_o, and of the likely ages of existing families, from the plot below. I have computed the characteristic time between collisions in the asteroid belt of a size ratio greater of equal to d_1/d_o, for 4 sizes of target asteroids, d_o. The solid curves to the lower right are the characteristic times for a single object...

  1. Dynamic wind turbine models in power system simulation tool DIgSILENT

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, A.D.; Iov, F.; Soerensen, Poul.; Cutululis, N.; Jauch, C.; Blaabjerg, F.

    2007-08-15

    This report presents a collection of models and control strategies developed and implemented in the power system simulation tool PowerFactory DIgSILENT for different wind turbine concepts. It is the second edition of Risoe-R-1400(EN) and it gathers and describes a whole wind turbine model database built-op and developed during several national research projects, carried out at Risoe DTU National Laboratory for Sustainable Energy and Aalborg University, in the period 2001-2007. The overall objective of these projects was to create a wind turbine model database able to support the analysis of the interaction between the mechanical structure of the wind turbine and the electrical grid during different operational modes. The report provides thus a description of the wind turbines modelling, both at a component level and at a system level. The report contains both the description of DIgSILENT built-in models for the electrical components of a grid connected wind turbine (e.g. induction generators, power converters, transformers) and the models developed by the user, in the dynamic simulation language DSL of DIgSILENT, for the non-electrical components of the wind turbine (wind model, aerodynamic model, mechanical model). The initialisation issues on the wind turbine models into the power system simulation are also presented. The main attention in the report is drawn to the modelling at the system level of the following wind turbine concepts: (1) Fixed speed active stall wind turbine concept (2) Variable speed doubly-fed induction generator wind turbine concept (3) Variable speed multi-pole permanent magnet synchronous generator wind turbine concept These wind turbine concept models can be used and even extended for the study of different aspects, e.g. the assessment of power quality, control strategies, connection of the wind turbine at different types of grid and storage systems. Different control strategies have been developed and implemented for these wind turbine

  2. Implementation of IEC Generic Model of Type 1 Wind Turbine Generator in DIgSILENT PowerFactory

    DEFF Research Database (Denmark)

    Zhao, Haoran; Wu, Qiuwei; Margaris, Ioannis

    2013-01-01

    The implementation method for the International Electrotechnical Commission (IEC) generic models of Type 1 wind turbine generator (WTG) in DIgSILENT PowerFactory is presented. The following items are described, i.e. model structure, model blocks and how to implement these blocks in the PowerFactory...

  3. An initial perspective of S-asteroid subtypes within asteroid families

    Science.gov (United States)

    Kelley, M. S.; Gaffey, M. J.

    1993-01-01

    Many main belt asteroids cluster around certain values of semi-major axis (a), inclination (i), and eccentricity (e). Hirayama was the first to notice these concentrations which he interpreted as evidence of disruptions of larger parent bodies. He called these clusters 'asteroid families'. The term 'families' is increasingly reserved for genetic associations to distinguish them from clusters of unknown or purely dynamical origin (e.g. the Phocaea cluster). Members of a genetic asteroid family represent fragments derived from various depths within the original parent planetesimal. Thus, family members offer the potential for direct examination of the interiors of parent bodies which have undergone metamorphism and differentiation similar to that occurring in the inaccessible interiors of terrestrial planets. The differentiation similar to that occurring in the inaccessible interiors of terrestrial planets. The condition that genetic family members represent the fragments of a parent object provides a critical test of whether an association (cluster in proper element space) is a genetic family. Compositions (types and relative abundances of materials) of family members must permit the reconstruction of a compositionally plausible parent body. The compositions of proposed family members can be utilized to test the genetic reality of the family and to determine the type and degree of internal differentiation within the parent planetesimal. The interpretation of the S-class mineralogy provides a preliminary evaluation of family memberships. Detailed mineralogical and petrological analysis was done based on the reflectance spectra of 39 S-type asteroids. The result is a division of the S-asteroid class into seven subtypes based on compositional differences. These subtypes, designated S(I) to S(VII), correspond to surface silicate assemblages ranging from monomineralic olivine (dunites) through olivine-pyroxene mixtures to pure pyroxene or pyroxene-feldspar mixtures

  4. Comets, Asteroids, Meteorites, and the Origin of the Biosphere

    Science.gov (United States)

    Hoover, Richard B.

    2006-01-01

    photoautotrophs and chemolithotrophs such as the motile filamentous cyanobacteria (e.g., Calothrix, Oscillatoria, Phormidium, and Spirulina) that grow in geothermal springs and geysers of Earth at temperatures ranging fiom 320K to 345K and are also found growing in cold polar desert soils. The mineralized remains of morphotypes of all of these cyanobacteria have also been found in the Orgueil CI1 and the Murchison CN2 carbonaceous meteorites that may derive from cometary parent bodies. Observational results that support the hypothesis that liquid water can in active regions just beneath the surface of comets and that comets, carbonaceous meteorites, and asteroids may have played a significant role in the origin and evolution of the Biosphere and in the distribution of microbial life throughout the Solar System.

  5. BILLIARDS: Baseline Instrumented Lithology Lander, Inspector and Asteroid Redirection Demonstration System

    Science.gov (United States)

    Marcus, Matthew; Sloane, Joshua; Ortiz, Oliver; Barbee, Brent

    2015-01-01

    BILLIARDS Baseline Instrumented Lithology Lander, Inspector, and Asteroid Redirection Demonstration System Proposed demonstration mission for Billiard-Ball concept Select asteroid pair with natural close approach to minimize cost and complexity Primary Objectives Rendezvous with a small (10m), near Earth (alpha) asteroid Maneuver the alpha asteroid to a collision with a 100m (beta) asteroid Produce a detectable deflection or disruption of the beta asteroid Secondary objectives Contribute knowledge of asteroid composition and characteristics Contribute knowledge of small-body formation Opportunity for international collaboration

  6. Harmonic Domain Modelling of Transformer Core Nonlinearities Using the DIgSILENT PowerFactory Software

    DEFF Research Database (Denmark)

    Bak, Claus Leth; Bak-Jensen, Birgitte; Wiechowski, Wojciech

    2008-01-01

    This paper demonstrates the results of implementation and verification of an already existing algorithm that allows for calculating saturation characteristics of singlephase power transformers. The algorithm was described for the first time in 1993. Now this algorithm has been implemented using...... the DIgSILENT Programming Language (DPL) as an external script in the harmonic domain calculations of a power system analysis tool PowerFactory [10]. The algorithm is verified by harmonic measurements on a single-phase power transformer. A theoretical analysis of the core nonlinearities phenomena...... in single and three-phase transformers is also presented. This analysis leads to the conclusion that the method can be applied for modelling nonlinearities of three-phase autotransformers....

  7. Modeling of the wind power plant using software DIgSILENT Power factory

    International Nuclear Information System (INIS)

    Mladenovski, Ljubisha; Iliev, Atanas; Fushtikj, Vangel

    2004-01-01

    This paper presents a method for creating a model of the wind power plant NORDEX N-60 in the DIgSILENT Power factory software. At the beginning, the characteristics of the wind power plant and the used software are shortly described. The next step is modeling the part of the power system where the wind power plant will be connected to the grid The modeling of the turbine part and the generator part of the wind power plant is made with blocks, which are part of the machine block of the composite model. Finally, the results obtained from performed practically oriented simulations are presented in graphical form. Design of the model of the wind power plant NORDEX N-60 was performed at the Faculty of Electrical Engineering, at the University of Rostock, Germany, as a part of the DYSIMAC project. (Author)

  8. Validación de la entrevista diagnóstica para estudios genéticos (DIGS en Colombia.

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Palacio

    2004-03-01

    Full Text Available Objetivo: validar la entrevista diagnóstica para estudios genéticos (DIGS 3.0 en Colombia. Métodos: se hicieron dos traducciones del inglés al español del DIGS y se hizo traducción en sentido inverso (al inglés de cada una. Un comité de revisión verificó la equivalencia translingüística y transcultural. Se evaluó la confiabilidad examen-reexamen e interevaluador del DIGS 3.0 en 65 y 91 pacientes, respectivamente, mediante el cálculo de kappa de Cohen. Resultados: el DIGS 3.0 mostró ser comprensible, con validez de apariencia y de contenido. La confiabilidad interevaluador fue excelente para esquizofrenia (k=0,81, IC95%: 0,68-0,93, trastorno bipolar (k=0,87, IC95%: 0,75-0,99, trastorno depresivo mayor (k=0,86, IC95%: 0,7- 1 y ausencia de trastorno psiquiátrico (k=0,88, IC95%: 0,71-1; fue buena para otro diagnóstico psiquiátrico (k=0,65, IC95%: 0,41-0,89 y pobre para trastorno esquizoafectivo (k=0,37, IC95%: -0,02-0,76. La confiabilidad examen-reexamen fue excelente para todos los diagnósticos (k>0,8, excepto para otro diagnóstico psiquiátrico (k=0,64, IC95%: 0,31-0,96, donde fue buena. Conclusiones: la versión en español del DIGS para Colombia mostró comprensibilidad, validez de apariencia y de contenido, y confiabilidad examen-reexamen e interevaluador. Es una herramienta útil para estudios genéticos en esquizofrenia y en trastornos afectivos.

  9. Trojan Asteroid Lightcurves: Probing Internal Structure and the Origins

    Science.gov (United States)

    Ryan, E. L.

    2017-12-01

    Studies of the small bodies of the solar system reveal important clues about the condensation and formation of planetesimal bodies, and ultimately planets in planetary systems. Dynamics of small bodies have been utilized to model giant planet migration within our solar system, colors have been used to explore compositional gradients within the protoplanetary disk, & studies of the size-frequency distribution of main belt asteroids may reveal compositional dependences on planetesimal strength limiting models of planetary growth from collisional aggregration. Studies of the optical lightcurves of asteroids also yield important information on shape and potential binarity of asteroidal bodies. The K2 mission has allowed for the unprecedented collection of Trojan asteroid lightcurves on a 30 minute cadence for baselines of 10 days, in both the L4 and L5 Trojan clouds. Preliminary results from the K2 mission suggest that Trojan asteroids have bulk densities of 1 g/cc and a binary fraction ≤ 33 percent (Ryan et al., 2017, Astronomical Journal, 153, 116), however Trojan lightcurve data is actively being collected via the continued K2 mission. We will present updated results of bulk density and binary fraction of the Trojan asteroids and compare these results to other small body populations, including Hilda asteroids, transNeptunian objects and comet nuclei to test dynamical models of the origins of these populations.

  10. Generalized Calibration of the Polarimetric Albedo Scale of Asteroids

    Science.gov (United States)

    Lupishko, D. F.

    2018-03-01

    Six different calibrations of the polarimetric albedo scale of asteroids have been published so far. Each of them contains its particular random and systematic errors and yields its values of geometric albedo. On the one hand, this complicates their analysis and comparison; on the other hand, it becomes more and more difficult to decide which of the proposed calibrations should be used. Moreover, in recent years, new databases on the albedo of asteroids obtained from the radiometric surveys of the sky with the orbital space facilities (the InfraRed Astronomical Satellite (IRAS), the Japanese astronomical satellite AKARI (which means "light"), the Wide-field Infrared Survey Explorer (WISE), and the Near-Earth Object Wide-field Survey Explorer (NEOWISE)) have appeared; and the database on the diameters and albedos of asteroids obtained from their occultations of stars has substantially increased. Here, we critically review the currently available calibrations and propose a new generalized calibration derived from the interrelations between the slope h and the albedo and between P min and the albedo. This calibration is based on all of the available series of the asteroid albedos and the most complete data on the polarization parameters of asteroids. The generalized calibration yields the values of the polarimetric albedo of asteroids in the system unified with the radiometric albedos and the albedos obtained from occultations of stars by asteroids. This, in turn, removes the difficulties in their comparison, joint analysis, etc.

  11. Size distributions of member asteroids in seven Hirayama families

    International Nuclear Information System (INIS)

    Mikami, Takao; Ishida, Keiichi.

    1990-01-01

    The size distributions of asteroids in the seven Hirayama families are studied for newly assigned member asteroids in the diameter range of about 10 to 100 km. The size distributions for the different families are expressed by the power-law functions with distinctly different power-law indices. The power-law indices for families with small mean orbital inclinations are about 2.5 to 3.0. On the other hand, the power-law indices for families with large mean orbital inclinations are significantly smaller than 2.5. This indicates that the smaller asteroids were removed preferentially from these families after their formation. It is thought that the smaller asteroids left behind the families were dispersed into the main belt. It is consistent with the fact that the power-law index for the size distribution of asteroids with diameters smaller than 25 km in the main belt is larger than the power-law indices for the size distributions of asteroids in the families. This segregation due to the asteroid size can be caused by a drag force caused by the ambient matter deposited on the invariable place of the solar system during the early evolutionary stage. (author)

  12. Redox effects in ordinary chondrites and implications for asteroid spectrophotometry

    Science.gov (United States)

    Mcsween, Harry Y., Jr.

    1992-01-01

    The sensitivity of reflectance spectra to mean ferrous iron content and olivine and pyroxene proportion enhancements in the course of metamorphic oxidation is presently used to examine whether metamorphically-induced ranges in mineralogy, and corresponding spectral parameters, may explain the observed variations in S-asteroid rotational spectra. The predicted spectral variations within any one chondrite class are, however, insufficient to account for S-asteroid rotational spectra, and predicted spectral-range slopes have a sign opposite to the rotational measurements. Metamorphic oxidation is found unable to account for S-asteroid rotational spectra.

  13. Reanalysis of Asteroid Families Structure Through Visible Spectroscopy

    Science.gov (United States)

    Mothé-Diniz, T.; Carvano, J.; Roig, F.; Lazzaro, D.

    In this work we re-analyse the presence of interlopers in asteroid families based on a larger spectral database and on a family determination which makes use of a larger set of proper elements. The asteroid families were defined using the HCM method (Zappalà et al. 1995) on the set of proper elements for 110,000 asteroids available at the Asteroid Dynamic Site (AstDyS http://hamilton.dm.unipi.it/astdys )). The spectroscopic analysis is performed using spectra on the 0.44-0.92 μ m range observed by the SMASS Xu et al. 1995, SMASSII (Bus and Binzel, 2002) and 3OS2 (Lazzaro et al. 2002) surveys, which together total around 2140 asteroids with observed spectra. The asteroid taxonomy used is the Bus taxonomy (Bus et al. 2000). A total of 22 two families were analysed . The families of Vesta, Eunomia, Hoffmeister, Dora, Merxia, Agnia, and Koronis were found to be spectrally homogeneous, which confirms previous studies. The Veritas family, on the other hand, which is quoted in the literature as an heterogeneous family was found to be quite homogeneous in the present work. The Eos family is noteworthy for being at one time spectrally heterogeneous and quite different from the background population. References Bus, S. J., and R. P. Binzel 2002. Phase II of the Small Main-Belt Asteroid Spectroscopic Survey - The Observations. Icarus 158, 106-145. Bus, S. J., R. P. Binzel, and T. H. Burbine 2000. A New Generation of Asteroid Taxonomy. Meteoritics and Planetary Science, vol. 35, Supplement, p.A36 35, 36 +. Lazzaro, D., C. A. Angeli, T. Mothe-Diniz, J. M. Carvano, R. Duffard, and M. Florczak 2002. The superficial characterization of a large sample of asteroids: the S3OS2. Bulletin of the American Astronomical Society 34, 859 +. Xu, S., R. P. Binzel, T. H. Burbine, and S. J. Bus 1995. Small main-belt asteroid spectroscopic survey: Initial results. Icarus 115, 1-35. Zappala, V., P. Bendjoya, A. Cellino, P. Farinella, and C. Froeschle 1995. Asteroid families: Search of a 12

  14. NEOWISE REACTIVATION MISSION YEAR ONE: PRELIMINARY ASTEROID DIAMETERS AND ALBEDOS

    Energy Technology Data Exchange (ETDEWEB)

    Nugent, C. R.; Cutri, R. M. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Mainzer, A.; Masiero, J.; Bauer, J.; Kramer, E.; Sonnett, S.; Stevenson, R. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Grav, T. [Planetary Science Institute, Tucson, AZ (United States); Wright, E. L., E-mail: cnugent@ipac.caltech.edu [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)

    2015-12-01

    We present preliminary diameters and albedos for 7956 asteroids detected in the first year of the NEOWISE Reactivation mission. Of those, 201 are near-Earth asteroids and 7755 are Main Belt or Mars-crossing asteroids. 17% of these objects have not been previously characterized using the Near-Earth Object Wide-field Infrared Survey Explorer, or “NEOWISE” thermal measurements. Diameters are determined to an accuracy of ∼20% or better. If good-quality H magnitudes are available, albedos can be determined to within ∼40% or better.

  15. Photometry and shape modeling of Mars crosser asteroid (1011 Laodamia

    Directory of Open Access Journals (Sweden)

    Apostolovska G.

    2014-01-01

    Full Text Available An analysis of photometric observations of Mars crosser asteroid 1011 Laodamia conducted at Bulgarian National Astronomical Observatory Rozhen over a twelve year interval (2002, 2003, 2004, 2006, 2007, 2008, 2011, 2012 and 2013 is made. Based on the obtained lightcurves the spin vector, sense of rotation, and preliminary shape model of (1011 Laodamia have been determined using the lightcurve inversion method. The aim of this investigation is to increase the set of asteroids with known spin and shape parameters and to contribute in improving the model in combination with other techniques and sparse data produced by photometric asteroid surveys such as Pan-STARRS or GAIA.

  16. Identification of families among highly inclined asteroids

    Science.gov (United States)

    Gil-Hutton, R.

    2006-07-01

    A dataset of 3652 high-inclination numbered asteroids was analyzed to search for dynamical families. A fully automated multivariate data analysis technique was applied to identify the groupings. Thirteen dynamical families and twenty-two clumps were found. When taxonomic information is available, the families show cosmochemical consistency and support an interpretation based on a common origin from a single parent body. Four families and three clumps found in this work show a size distribution which is compatible with a formation due to a cratering event on the largest member of the family, and also three families have B- or related taxonomic types members, which represents a 14% of the B-types classified by Bus and Binzel [2002. Icarus 158, 146-177].

  17. Asteroid orbital error analysis: Theory and application

    Science.gov (United States)

    Muinonen, K.; Bowell, Edward

    1992-01-01

    We present a rigorous Bayesian theory for asteroid orbital error estimation in which the probability density of the orbital elements is derived from the noise statistics of the observations. For Gaussian noise in a linearized approximation the probability density is also Gaussian, and the errors of the orbital elements at a given epoch are fully described by the covariance matrix. The law of error propagation can then be applied to calculate past and future positional uncertainty ellipsoids (Cappellari et al. 1976, Yeomans et al. 1987, Whipple et al. 1991). To our knowledge, this is the first time a Bayesian approach has been formulated for orbital element estimation. In contrast to the classical Fisherian school of statistics, the Bayesian school allows a priori information to be formally present in the final estimation. However, Bayesian estimation does give the same results as Fisherian estimation when no priori information is assumed (Lehtinen 1988, and reference therein).

  18. Geographos asteroid flyby and autonomous navigation study

    Energy Technology Data Exchange (ETDEWEB)

    Ng, L.C.; Pines, D.J. [Lawrence Livermore National Lab., CA (United States); Patz, B.J.; Perron, D.C. [Coleman Research Corp., Orlando, FL (United States)

    1993-02-22

    Deep Space Program Science Experiment (DSPSE), also known as Clementine, is a collection of science experiments conducted in near-earth with the goal of demonstrating Strategic Defense Initiative Office (SDIO) developed technologies. The 785 lb (fully fueled) spacecraft will be launched into low Earth orbit in February 1994 together with a Star 37 solid kick motor and interstage. After orbit circulation using Clementine`s 110 lb Delta-V thruster, the Star 37 will execute a trans-lunar injection burn that will send the spacecraft toward lunar obit. The 110-lb will then be used in a sequence of burns to insert Clementine into a trimmed, polar orbit around the moon. After a two month moon mapping mission, Clementine will execute burns to leave lunar orbit, sling-shot around Earth, and flyby the moon on a 9.4 million km journey toward the asteroid Geographos. After about three months in transit, Clementine will attempt a flyby with a closest point of approach of 100 km from the asteroid on August 31, 1994. During its approach to Geographos, Clementine will be tracked by the Deep Space Network (DSN) and receive guidance updates. The last update and correction burn will occur about one day out of the flyby. Multiple experiments will be performed at key events during the mission that utilize Clementine`s SDIO-derived resources, including its Star Trackers, UV/Vis camera, infrared sensors (NWIR and LWIR), and high resolution laser radar (HIRes/LIDAR). In addition to the evaluation of SDIO algorithms and sensors, high resolution imagery will be obtained while the spacecraft is in Earth orbit, lunar obit and during the Geographos flyby. This paper describes the results of a study on the precision guidance, navigation, and intercept strategy for the flyby mission.

  19. Compositional characterization of asteroid (16) Psyche

    Science.gov (United States)

    Sanchez, Juan; Reddy, Vishnu; Shepard, Michael K.; Thomas, Cristina; Cloutis, Edward

    2016-10-01

    We present near-infrared spectra (0.7-2.5 microns) of asteroid (16) Psyche obtained with the NASA Infrared Telescope Facility. Rotationally-resolved spectra were obtained during three nights between December 2015 and February 2016. These data have been combined with three-dimensional shape models of Psyche generated with the SHAPE software package (Magri et al. 2007). From each spectrum, the band center, band depth and spectral slope were measured. We found that the band center varies from 0.92 to 0.94 microns with rotation phase, with an average value of 0.932±0.006 microns. The band depth was found to vary from 1.0 to 1.5±0.1%. Spectral slope values range from 0.25 to 0.35±0.01 microns-1, with rotation phase. We observed a possible anti-correlation between band depth and radar albedo. Using the band depth along with a new laboratory spectral calibration we estimated that Psyche has an average orthopyroxene abundance of 6±1%. The mass-deficit region of Psyche (longitudes ~ 0°-40°), characterized by having the highest radar albedo of the asteroid, also shows the highest value for the spectral slope and the minimum band depth, while the antipode of this region (longitudes ~ 180°-230°), where the radar albedo reaches its lowest value, shows a maximum in band depth and less steep spectral slopes. These results could suggest that the metal-poor antipode region has thicker regolith rich in pyroxene compared to the mass-deficit region.

  20. GRASPING THE NATURE OF POTENTIALLY HAZARDOUS ASTEROIDS

    Energy Technology Data Exchange (ETDEWEB)

    Perna, D.; Barucci, M. A.; Fornasier, S.; Deshapriya, J. D. P. [LESIA—Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, F-92195 Meudon (France); Dotto, E.; Ieva, S.; Epifani, E. Mazzotta [INAF—Osservatorio Astronomico di Roma, Via Frascati 33, I-00040 Monte Porzio Catone (Roma) (Italy); Bernardi, F. [SpaceDyS, via Mario Giuntini 63, I-56023 Cascina (Pisa) (Italy); Luise, F. De [INAF—Osservatorio Astronomico di Teramo, via Mentore Maggini snd, I-64100 Teramo (Italy); Perozzi, E. [Deimos Space, Strada Buchesti 75-77, Bucharest (Romania); Rossi, A. [IFAC—CNR, via Madonna del Piano 10, I-50019 Sesto Fiorentino (Firenze) (Italy); Micheli, M., E-mail: davide.perna@obspm.fr [ESA—NEOCC, ESRIN, via Galileo Galilei 64, I-00044 Frascati (Rome) (Italy)

    2016-01-15

    Through their delivery of water and organics, near-Earth objects (NEOs) played an important role in the emergence of life on our planet.  However, they also pose a hazard to the Earth, as asteroid impacts could significantly affect our civilization. Potentially hazardous asteroids (PHAs) are those that, in principle, could possibly impact the Earth within the next century, producing major damage. About 1600 PHAs are currently known, from an estimated population of 4700 ± 1450. However, a comprehensive characterization of the PHA physical properties is still missing. Here we present spectroscopic observations of 14 PHAs, which we have used to derive their taxonomy, meteorite analogs, and mineralogy. Combining our results with the literature, we investigated how PHAs are distributed as a function of their dynamical and physical properties. In general, the “carbonaceous” PHAs seem to be particularly threatening, because of their high porosity (limiting the effectiveness of the main deflection techniques that could be used in space) and low inclination and minimum orbit intersection distance (MOID) with the Earth (favoring more frequent close approaches). V-type PHAs also present low MOID values, which can produce frequent close approaches (as confirmed by the recent discovery of a limited space weathering on their surfaces). We also identified those specific objects that deserve particular attention because of their extreme rotational properties, internal strength, or possible cometary nature. For PHAs and NEOs in general, we identified a possible anti-correlation between the elongation and the rotational period, in the range of P{sub rot} ≈ 5–80 hr. This would be compatible with the behavior of gravity-dominated aggregates in rotational equilibrium. For periods ≳80–90 hr, such a trend stops, possibly under the influence of the YORP effect and collisions. However, the statistics is very low, and further observational and theoretical work is required

  1. Business analysis: The commercial mission of the International Asteroid Mission

    Science.gov (United States)

    The mission of the International Asteroid Mission (IAM) is providing asteroidal resources to support activities in space. The short term goal is to initiate IAM by mining a near-Earth, hydrous carbonaceous chondrite asteroid to service the nearer-term market of providing cryogenic rocket fuel in low lunar orbit (LLO). The IAM will develop and contract for the building of the transportation vehicles and equipment necessary for this undertaking. The long-term goal is to expand operations by exploiting asteroids in other manners, as these options become commercially viable. The primary business issues are what revenue can be generated from the baseline mission, how much will the mission cost, and how funding for this mission can be raised. These issues are addressed.

  2. Calculating the momentum enhancement factor for asteroid deflection studies

    International Nuclear Information System (INIS)

    Heberling, Tamra; Gisler, Galen; Plesko, Catherine; Weaver, Robert

    2017-01-01

    The possibility of kinetic-impact deflection of threatening near-Earth asteroids will be tested for the first time in the proposed AIDA (Asteroid Impact Deflection Assessment) mission, involving NASAs DART (Double Asteroid Redirection Test). The impact of the DART spacecraft onto the secondary of the binary asteroid 65803 Didymos at a speed of 5 to 7 km/s is expected to alter the mutual orbit by an observable amount. Furthermore, the velocity transferred to the secondary depends largely on the momentum enhancement factor, typically referred to as beta. Here, we use two hydrocodes developed at Los Alamos, RAGE and PAGOSA, to calculate an approximate value for beta in laboratory-scale benchmark experiments. Convergence studies comparing the two codes show the importance of mesh size in estimating this crucial parameter.

  3. An interstellar origin for Jupiter's retrograde co-orbital asteroid

    Science.gov (United States)

    Namouni, F.; Morais, M. H. M.

    2018-06-01

    Asteroid (514107) 2015 BZ509 was discovered recently in Jupiter's co-orbital region with a retrograde motion around the Sun. The known chaotic dynamics of the outer Solar system have so far precluded the identification of its origin. Here, we perform a high-resolution statistical search for stable orbits and show that asteroid (514107) 2015 BZ509 has been in its current orbital state since the formation of the Solar system. This result indicates that (514107) 2015 BZ509 was captured from the interstellar medium 4.5 billion years in the past as planet formation models cannot produce such a primordial large-inclination orbit with the planets on nearly coplanar orbits interacting with a coplanar debris disc that must produce the low-inclination small-body reservoirs of the Solar system such as the asteroid and Kuiper belts. This result also implies that more extrasolar asteroids are currently present in the Solar system on nearly polar orbits.

  4. Asteroid collisional history - Effects on sizes and spins

    International Nuclear Information System (INIS)

    Davis, D.R.; Weidenschilling, S.J.; Farinella, P.; Paolicchi, P.; Binzel, R.P.

    1989-01-01

    The effects of asteroid collisional history on sizes and spins of present-day objects are discussed. Collisional evolution studies indicate that collisions have altered the spin-rates of small bodies, but that the largest asteroids may have retained their primordial rotation rates. Most asteroids larger than 100 km diam have probably been shattered, but have gravitationally recaptured their fragments to form a rubble-pile structure. Large angular momentum asteroids appear to have Maclaurian spheroidal or Jacobi-ellipsoid-like shapes; some of them may have fissioned into binaries. An integrated size and spin collisional evolution model is presented, with two critical parameters: one which determines the spin rates for small fragments resulting from a shattering collision, and the other determines the fraction of impact angular momentum that is retained by the target. 36 refs

  5. NEAR EARTH ASTEROID TRACKING V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The Near-Earth Asteroid Tracking (NEAT) project began as a collaborative effort with the United States Air Force (USAF) in December 1995. It concentrated on the...

  6. The principle of equivalence and the Trojan asteroids

    International Nuclear Information System (INIS)

    Orellana, R.; Vucetich, H.

    1986-05-01

    An analysis of the Trojan asteroids motion has been carried out in order to set limits to possible violations to the principle of equivalence. Preliminary results, in agreement with general relativity, are reported. (author)

  7. Task-Specific Asteroid Simulants for Ground Testing, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The project will produce at least four asteroid simulants at high fidelity for mineral content and particle size, created through standardized inputs and documented...

  8. Carbonaceous Asteroid Volatile Recovery (CAVoR) system, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The Carbonaceous Asteroid Volatile Recovery (CAVoR) system produces water and hydrogen-rich syngas for propellant production, life support consumables, and...

  9. HARDERSEN IRTF ASTEROID NIR REFLECTANCE SPECTRA V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset includes average near-infrared (NIR) reflectance spectra for 68 main-belt asteroids that were observed at the NASA Infrared Telescope Facility (IRTF),...

  10. EARTH ASTEROID DBP 24COLOR SURVEY V2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — Photometric spectra covering the range 0.32 - 1.08 micrometers for 285 numbered asteroids, as published in Chapman & Gaffey (1979b) and McFadden, et al. (1984).

  11. The CASLEO Polarimetric Survey of Main Belt Asteroids: Updated results

    Science.gov (United States)

    Gil-Hutton, R.; Cellino, A.; Cañada-Assandri, M.

    2011-10-01

    We present updated results of the polarimetric survey of main-belt asteroids at Complejo Astronómico El Leoncito (Casleo), San Juan, Argentina, using the 2.15 m telescope and the Torino and CASPROF polarimeters. The goals of this survey are to increase the database of asteroid polarimetry, to estimate diversity in polarimetric properties of asteroids belonging to different taxonomic classes, and to search for objects that exhibit anomalous polarimetric properties. The survey began in 2003, and data for a sample of more than 170 asteroids have been obtained, most of them having been polarimetrically observed for the first time. Using these data we find phase-polarization curves and polarimetric parameters for several taxonomic classes.

  12. Physical Mechanism of Comet (and Asteroid) Outbursts: The Movie

    Science.gov (United States)

    Hartmann, W. K.

    2015-07-01

    A film made during impact experiments at NASA Ames illustrates a mechanism in which regolith can become gas charged and then erupt to create outbursts as observed on comets (and "asteroids" such as 2060 Chiron).

  13. REDDY MAIN BELT ASTEROID SPECTRA V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains low-resolution (R~150) near-infrared (0.7-2.5 microns) spectra of 90 main belt asteroids observed with the SpeX instrument on the NASA...

  14. The size distribution of the earth-approaching asteroids

    Science.gov (United States)

    Rabinowitz, D. L.

    1993-01-01

    The discovery circumstances of the first asteroids ever observed outside the earth's atmosphere but within the neighborhood of the earth-moon system are described. Four natural objects with diameters in the range 5-50 m were detected during a search for earth-approaching asteroids conducted each month at the 0.91-m Spacewatch Telescope at Kitt Peak. An additional 19 earth approachers with sizes in the range 50 m to 5 km were discovered. These obervations determine the cumulative flux of asteroids near earth as a function of absolute magnitude. For asteroids larger than about 100 m, a power-law dependence with exponent of about 0.9 is observed, consistent with their evolution from the main-belt population. At about 10 m, the flux is more than two orders of magnitude greater than this power-law extrapolation.

  15. Spectral properties of near-Earth asteroids on cometary orbits

    Science.gov (United States)

    Popescu, M.; Vaduvescu, O.; de Leon, J.; Boaca, I. L.; Gherase, R. M.; Nedelcu, D. A.; INT students, I. N. G.

    2017-09-01

    We studied the spectral distributions of near-Earth asteroids on cometary orbits (NEACOs) in order to identify potential dormant or extinct comets among these objects. We present the spectral observations for 19 NEACOs obtained with Isaac Newton Telescope and Infrared Telescope Facility (IRTF). Although initially classified as asteroid, one of our targets - 2007 VA85 was confirmed to be active comet 333P/LINEAR on its 2016 appearance. We found that the NEACOs population is a mixing of different compositional classes.

  16. A radar survey of M- and X-class asteroids

    Czech Academy of Sciences Publication Activity Database

    Shepard, M.K.; Clark, B. E.; Nolan, M. C.; Howell, E. S.; Magri, C.; Giorgini, J. D.; Benner, L. A. M.; Ostro, S. J.; Harris, A. W.; Warner, B. D.; Pray, D. P.; Pravec, Petr; Fauerbach, M.; Bennett, T.; Klotz, A.; Behrend, R.; Correia, H.; Coloma, J.M.; Casulli, S.; Rivkin, A. S.

    2008-01-01

    Roč. 195, č. 1 (2008), s. 184-205 ISSN 0019-1035 R&D Projects: GA ČR(CZ) GA205/05/0604 Grant - others:NSF(US) AST-0605903; NSF(US) AST-0606704; NSF(US) AST-0607505; NASA (US) NNG06GI32G Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroids * asteroids composition * surfaces Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.268, year: 2008

  17. On the maximum amplitude of harmonics of an asteroid lightcurve

    Czech Academy of Sciences Publication Activity Database

    Harris, A. W.; Pravec, Petr; Galád, Adrián; Skiff, B.A.; Warner, B. D.; Világi, J.; Gajdoš, Š.; Carbognani, A.; Hornoch, Kamil; Kušnirák, Peter; Cooney jr., W. R.; Gross, J.; Terrell, D.; Higgins, D.; Bowell, E.; Koehn, B.W.

    2014-01-01

    Roč. 235, June (2014), s. 55-59 ISSN 0019-1035 R&D Projects: GA ČR GAP209/12/0229 Grant - others:SAV(SK) Vega 1/0670/13; NASA (US) NNX13AP56G Institutional support: RVO:67985815 Keywords : asteroids * asteroids rotation * photometry Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.038, year: 2014

  18. Monoclonal antibodies to Nocardia asteroides and Nocardia brasiliensis antigens.

    OpenAIRE

    Jiménez, T; Díaz, A M; Zlotnik, H

    1990-01-01

    Nocardia asteroides and Nocardia brasiliensis whole-cell extracts were used as antigens to generate monoclonal antibodies (MAbs). Six stable hybrid cell lines secreting anti-Nocardia spp. MAbs were obtained. These were characterized by enzyme-linked immunosorbent assay, Western blot (immunoblot), and immunofluorescence assay. Although all the MAbs exhibited different degrees of cross-reactivity with N. asteroides and N. brasiliensis antigens as well as with culture-filtrate antigens from Myco...

  19. LONG-TERM STABLE EQUILIBRIA FOR SYNCHRONOUS BINARY ASTEROIDS

    International Nuclear Information System (INIS)

    Jacobson, Seth A.; Scheeres, Daniel J.

    2011-01-01

    Synchronous binary asteroids may exist in a long-term stable equilibrium, where the opposing torques from mutual body tides and the binary YORP (BYORP) effect cancel. Interior of this equilibrium, mutual body tides are stronger than the BYORP effect and the mutual orbit semimajor axis expands to the equilibrium; outside of the equilibrium, the BYORP effect dominates the evolution and the system semimajor axis will contract to the equilibrium. If the observed population of small (0.1-10 km diameter) synchronous binaries are in static configurations that are no longer evolving, then this would be confirmed by a null result in the observational tests for the BYORP effect. The confirmed existence of this equilibrium combined with a shape model of the secondary of the system enables the direct study of asteroid geophysics through the tidal theory. The observed synchronous asteroid population cannot exist in this equilibrium if described by the canonical 'monolithic' geophysical model. The 'rubble pile' geophysical model proposed by Goldreich and Sari is sufficient, however it predicts a tidal Love number directly proportional to the radius of the asteroid, while the best fit to the data predicts a tidal Love number inversely proportional to the radius. This deviation from the canonical and Goldreich and Sari models motivates future study of asteroid geophysics. Ongoing BYORP detection campaigns will determine whether these systems are in an equilibrium, and future determination of secondary shapes will allow direct determination of asteroid geophysical parameters.

  20. Software Development for Asteroid and Variable Star Research

    Science.gov (United States)

    Sweckard, Teaghen; Clason, Timothy; Kenney, Jessica; Wuerker, Wolfgang; Palser, Sage; Giles, Tucker; Linder, Tyler; Sanchez, Richard

    2018-01-01

    The process of collecting and analyzing light curves from variable stars and asteroids is almost identical. In 2016 a collaboration was created to develop a simple fundamental way to study both asteroids and variable stars using methods that would allow the process to be repeated by middle school and high school students.Using robotic telescopes at Cerro Tololo (Chile), Yerkes Observatory (US), and Stone Edge Observatory (US) data were collected on RV Del and three asteroids. It was discovered that the only available software program which could be easily installed on lab computers was MPO Canopus. However, after six months it was determined that MPO Canopus was not an acceptable option because of the steep learning curve, lack of documentation and technical support.Therefore, the project decided that the best option was to design our own python based software. Using python and python libraries we developed code that can be used for photometry and can be easily changed to the user's needs. We accomplished this by meeting with our mentor astronomer, Tyler Linder, and in the beginning wrote two different programs, one for asteroids and one for variable stars. In the end, though, we chose to combine codes so that the program would be capable of performing photometry for both moving and static objects.The software performs differential photometry by comparing the magnitude of known reference stars to the object being studied. For asteroids, the image timestamps are used to obtain ephemeris of the asteroid from JPL Horizons automatically.

  1. Molecular identification of Coccidioides spp. in soil samples from Brazil

    OpenAIRE

    de Macêdo, Regina CL; Rosado, Alexandre S; da Mota, Fabio F; Cavalcante, Maria AS; Eulálio, Kelsen D; Filho, Antônio D; Martins, Liline MS; Lazéra, Márcia S; Wanke, Bodo

    2011-01-01

    Abstract Background Since 1991 several outbreaks of acute coccidioidomycosis (CM) were diagnosed in the semi-arid Northeast of Brazil, mainly related to disturbance of armadillo burrows caused by hunters while digging them for the capture of these animals. This activity causes dust contaminated with arthroconidia of Coccidioides posadasii, which, once inhaled, cause the mycosis. We report on the identification of C. posadasii in soil samples related to outbreaks of CM. Results Twenty four soi...

  2. In Situ Chemical Reduction (ISCR) for Removal of Persistent Pesticides; focus on kepone in tropical soils

    OpenAIRE

    Mouvet , Christophe; Bristeau , Sébastien; Amalric , Laurence; Dictor , Marie Christine; Mercier , Anne; Thannberger , Laurent; Mueller , Jim; Valkenburg , John; Seech , Alan; Przepiora , Andrezej; Molin , Josephine; Bucci , Edson Marcus

    2011-01-01

    Background/Objectives. The global use of organochlorine pesticides (OCPs) such as Lindane, DDT, Dieldrin, Kepone, Chlordane and Toxaphene has resulted in long-term soil impacts at many sites. Given the potential risks to human health and the environment, some OCP-impacted sites require treatment. In certain cases, the "dig-and-dump" approach is not practical due to magnitude of the problem, access issues, and/or resource constraints. Here "bioremediation" can be used to treat the soil on site...

  3. FY 1975 Report on results of Sunshine Project. Development of techniques of digging high-temperature beds (Conceptual designs of automatic digging systems); 1975 nendo koon chiso kussaku gijutsu no kaihatsu seika hokokusho. Jido kussaku system no gainen sekkei

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1976-03-31

    This project is aimed at development of automatic rotary table type digging apparatus capable of digging high-temperature beds of 3,000 to 5,000 m in depth, 400 degrees C and 500 kg/cm{sup 2}. The automatic excavation apparatus is designed based on the concept that the driller is separated from the running drawworks side for other works. However, it is operated manually in a traditional manner, when the bed for which it is to be used is under complex conditions, or when the bed properties require frequent changes in digging conditions with respect to bit load and speed of rotation. The apparatus works, when the bed is considered to be under essentially constant conditions at a fairly high depth, in such a way that a combination of bit load and speed of rotation is set by the driller, and the work line wound on the drawworks drum is let out to keep the bit load constant. It is equipped with, e.g., a controller, converter and brake operating device, detecting suspension load by the controller, when it increases, increasing speed of air motor after comparing the load with the reference level, and relaxing the brake, to keep the suspension load at the set level. When the suspension load decreases, on the other hand, the air motor is decelerated to tighten the brake. (NEDO)

  4. Authentic Learning Experiences for Educators through Summer Internships: Revising the DIG Texas Instructional Blueprints

    Science.gov (United States)

    Martinez, A. O.; Bohls-Graham, E.; Jacobs, B. E.; Ellins, K. K.

    2014-12-01

    Texas teachers have expressed a need for engaging activities for use in high school Earth science courses. With funding from the NSF, geoscience and education faculty from different institutions around the state collaborated with ten Earth science teachers to create five online Earth science instructional blueprints. The work is part of the DIG (Diversity and Innovation for Geosciences) Texas Instructional Blueprint project. A blueprint stitches together nine units for a yearlong Earth science course (scope and sequence). Each unit covers three weeks of teaching and contains lectures, readings, visualizations, lab investigations, learning activities, and other educational materials from credible sources, which are aligned with Texas state science standards for Earth and Space Science and the Earth Science Literacy Principles. Taken together, the collection of activities address the Next Generation Science Standards (NGSS). During summer 2014, three minority-serving secondary teachers completed a six-week internship at The University of Texas Institute for Geophysics (UTIG). As DIG Texas Education Interns, we organized and revised the content of the units, created scaffolding notes, and built blueprints by selecting groups of nine units from the project's current collection of twenty-one units. Because fieldwork is an important element of geoscience learning, we integrated virtual field trips into each unit. We (1) gained expertise in selecting high quality activities that directly correlate with state standards and address the Earth Science Literacy Principles; (2) developed a keen awareness of the value of the NGSS; (3) learned how to navigate through the NGSS website to track the relationships between the Science and Engineering Practices, Disciplinary Core Ideas, and Crosscutting Concepts for Earth science, as well as connections to other disciplines in the same grade level. Collaborating with other secondary Earth science teachers introduced each of us to new

  5. Alkaline electrolyzer and V2G system DIgSILENT models for demand response analysis in future distribution networks

    DEFF Research Database (Denmark)

    Diaz de Cerio Mendaza, Iker; Bak-Jensen, Birgitte; Chen, Zhe

    2013-01-01

    Grid instabilities originated by unsteady generation, characteristic consequence of some renewable energy resources such as wind and solar power, claims for new power balance solutions in largely penetrated systems. Denmark's solid investment in these energy sources has awaked a need of rethinking...... about the future control and operation of the power system. A widespread idea to face these challenges is to have a flexible demand easily adjustable to the system variations. Electrothermal loads, electric vehicles and hydrogen generation are among the most mentioned technologies capable to respond......, under certain strategies, to these variations. This paper presents two DIgSILENT PowerFactory models: an alkaline electrolyzer and a vehicle to the grid system. The models were performed using DIgSILENT Simulation Language, aiming to be used for long-term distribution systems simulations. Two voltage...

  6. Fem spørgsmål du bør stille dig selv som ejerleder

    DEFF Research Database (Denmark)

    Bennedsen, Morten; Westergård-Nielsen, Niels

    2016-01-01

    Det tager 10 år at implementere et ejerskifte, men ny forskning viser, at alt for mange virksomhedsejere udskyder at gå i gang. Se dig selv i øjnene og gå i kast med de store spørgsmål for din egen, din virksomheds og din families skyld.......Det tager 10 år at implementere et ejerskifte, men ny forskning viser, at alt for mange virksomhedsejere udskyder at gå i gang. Se dig selv i øjnene og gå i kast med de store spørgsmål for din egen, din virksomheds og din families skyld....

  7. AsteroidFinder - the space-borne telescope to search for NEO Asteroids

    Science.gov (United States)

    Hartl, M.; Mosebach, H.; Schubert, J.; Michaelis, H.; Mottola, S.; Kührt, E.; Schindler, K.

    2017-11-01

    This paper presents the mission profile as well as the optical configuration of the space-borne AsteroidFinder telescope. Its main objective is to retrieve asteroids with orbits interior to the earth's orbit. The instrument requires high sensitivity to detect asteroids with a limiting magnitude of equal or larger than 18.5mag (V-Band) and astrometric accuracy of 1arcsec (1σ). This requires a telescope aperture greater than 400cm2, high image stability, detector with high quantum efficiency (peak > 90%) and very low noise, which is only limited by zodiacal background. The telescope will observe the sky between 30° and 60° in solar elongation. The telescope optics is based on a Cook type TMA. An effective 2°×2° field of view (FOV) is achieved by a fast F/3.4 telescope with near diffraction-limited performance. The absence of centre obscuration or spiders in combination with an accessible intermediate field plane and exit pupil allow for efficient stray light mitigation. Design drivers for the telescope are the required point spread function (PSF) values, an extremely efficient stray light suppression (due to the magnitude requirement mentioned above), the detector performance, and the overall optical and mechanical stability for all orientations of the satellite. To accommodate the passive thermal stabilization scheme and the necessary structural stability, the materials selection for the telescope main structure and the mirrors are of vital importance. A focal plane with four EMCCD detectors is envisaged. The EMCCD technology features shorter integration times, which is in favor regarding the pointing performance of the satellite. The launch of the mission is foreseen for the year 2013 with a subsequent mission lifetime of at least 1 year.

  8. A compatible interaction of Alternaria brassicicola with Arabidopsis thaliana ecotype DiG: evidence for a specific transcriptional signature

    Directory of Open Access Journals (Sweden)

    Gepstein Shimon

    2009-03-01

    Full Text Available Abstract Background The interaction of Arabidopsis with Alternaria brassicicola provides a model for disease caused by necrotrophs, but a drawback has been the lack of a compatible pathosystem. Infection of most ecotypes, including the widely-studied line Col-0, with this pathogen generally leads to a lesion that does not expand beyond the inoculated area. This study examines an ecotype, Dijon G (DiG, which is considered sensitive to A. brassicicola. Results We show that the interaction has the characteristics of a compatible one, with expanding rather than limited lesions. To ask whether DiG is merely more sensitive to the pathogen or, rather, interacts in distinct manner, we identified genes whose regulation differs between Col-0 and DiG challenged with A. brassicicola. Suppression subtractive hybridization was used to identify differentially expressed genes, and their expression was verified using semi-quantitative PCR. We also tested a set of known defense-related genes for differential regulation in the two plant-pathogen interactions. Several known pathogenesis-related (PR genes are up-regulated in both interactions. PR1, and a monooxygenase gene identified in this study, MO1, are preferentially up-regulated in the compatible interaction. In contrast, GLIP1, which encodes a secreted lipase, and DIOX1, a pathogen-response related dioxygenase, are preferentially up-regulated in the incompatible interaction. Conclusion The results show that DiG is not only more susceptible, but demonstrate that its interaction with A. brassicicola has a specific transcriptional signature.

  9. Supporting Ngss-Congruent Instruction in Earth & Space Science Through Educator Implementation and Feedback: Refining the Dig Texas Blueprints

    Science.gov (United States)

    Jacobs, B. E.; Bohls-Graham, C. E.; Ellins, K. K.; Riggs, E. M.; Serpa, L. F.; Stocks, E.; McIver, H.; Sergent, C.

    2015-12-01

    The development of the Next Generation Science Standards (NGSS) as a framework around which to guide K-12 science instruction has generated a call for rigorous curricula that meets the demand for developing a workforce with expertise in tackling modern Earth science challenges. The Diversity and Innovation in Geosciences (DIG) Texas Blueprints project addresses this need for quality, aligned curricula with educator-vetted, freely available resources carefully selected and compiled into three week thematic units that have been aligned with the Earth Science Literacy Principles and the NGSS. These units can then be packaged into customized blueprints for a year-long Earth & Space Science course that engages students in the relevant disciplinary core ideas, crosscutting concepts and science and engineering practices. As part of supporting NGSS-congruent instruction, each unit has extensive scaffolding notes for the learning activities selected for that unit. Designed with both the new and veteran teacher in mind, these scaffolding notes yield information regarding advanced teacher preparation, student prerequisite skills, and potential challenges that might arise during classroom implementation. Feedback from Texas high school teachers implementing the DIG Texas Blueprints in the classroom, in addition to that of university secondary education majors in a preparation course utilizing the blueprints, instigated the most recent revisions to these scaffolding notes. The DIG Texas Blueprints Educator Intern Team charged with these revisions then determined which learning activities became candidates for either inclusion in the refined units, retention as an additional resource, or elimination from the blueprints. This presentation will focus on the development of these scaffolding notes and their role in supporting congruence with the NGSS. A review of the second year of implementation of the blueprints and the feedback that generated the final revisions will be shared

  10. OSIRIS-REx Asteroid Sample Return Mission Image Analysis

    Science.gov (United States)

    Chevres Fernandez, Lee Roger; Bos, Brent

    2018-01-01

    NASA’s Origins Spectral Interpretation Resource Identification Security-Regolith Explorer (OSIRIS-REx) mission constitutes the “first-of-its-kind” project to thoroughly characterize a near-Earth asteroid. The selected asteroid is (101955) 1999 RQ36 (a.k.a. Bennu). The mission launched in September 2016, and the spacecraft will reach its asteroid target in 2018 and return a sample to Earth in 2023. The spacecraft that will travel to, and collect a sample from, Bennu has five integrated instruments from national and international partners. NASA's OSIRIS-REx asteroid sample return mission spacecraft includes the Touch-And-Go Camera System (TAGCAMS) three camera-head instrument. The purpose of TAGCAMS is to provide imagery during the mission to facilitate navigation to the target asteroid, confirm acquisition of the asteroid sample and document asteroid sample stowage. Two of the TAGCAMS cameras, NavCam 1 and NavCam 2, serve as fully redundant navigation cameras to support optical navigation and natural feature tracking. The third TAGCAMS camera, StowCam, provides imagery to assist with and confirm proper stowage of the asteroid sample. Analysis of spacecraft imagery acquired by the TAGCAMS during cruise to the target asteroid Bennu was performed using custom codes developed in MATLAB. Assessment of the TAGCAMS in-flight performance using flight imagery was done to characterize camera performance. One specific area of investigation that was targeted was bad pixel mapping. A recent phase of the mission, known as the Earth Gravity Assist (EGA) maneuver, provided images that were used for the detection and confirmation of “questionable” pixels, possibly under responsive, using image segmentation analysis. Ongoing work on point spread function morphology and camera linearity and responsivity will also be used for calibration purposes and further analysis in preparation for proximity operations around Bennu. Said analyses will provide a broader understanding

  11. The Main Asteroid Belt: The Crossroads of the Solar System

    Science.gov (United States)

    Michel, Patrick

    2015-08-01

    Orbiting the Sun between Mars and Jupiter, main belt asteroids are leftover planetary building blocks that never accreted enough material to become planets. They are therefore keys to understanding how the Solar System formed and evolved. They may also provide clues to the origin of life, as similar bodies may have delivered organics and water to the early Earth.Strong associations between asteroids and meteorites emerged thanks to multi-technique observations, modeling, in situ and sample return analyses. Spacecraft images revolutionized our knowledge of these small worlds. Asteroids are stunning in their diversity in terms of physical properties. Their gravity varies by more orders of magnitude than its variation among the terrestrial planets, including the Moon. Each rendezvous with an asteroid thus turned our geological understanding on its head as each asteroid is affected in different ways by a variety of processes such as landslides, faulting, and impact cratering. Composition also varies, from ice-rich to lunar-like to chondritic.Nearly every asteroid we see today, whether of primitive or evolved compositions, is the product of a complex history involving accretion and one or more episodes of catastrophic disruption that sometimes resulted in families of smaller asteroids that have distinct and indicative petrogenic relationships. These families provide the best data to study the impact disruption process at scales far larger than those accessible in laboratory. Tens, perhaps hundreds, of early asteroids grew large enough to thermally differentiate. Their traces are scattered pieces of their metal-rich cores and, more rarely, their mantles and crusts.Asteroids represent stages on the rocky road to planet formation. They have great stories to tell about the formation and evolution of our Solar System as well as other planetary systems: asteroid belts seem common around Sun-like stars. We will review our current knowledge on their properties, their link to

  12. FY 1974 Report on results of Sunshine Project. Feasibility study on digging high-temperature beds; 1974 nendo koon chiso kussaku ni kansuru feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1975-03-31

    The desired target geothermal conditions for which the digging equipment is to be developed are 3,000 to 5,000 m as depth, 400 degrees C as temperature and 500 kg/cm{sup 2} as pressure. As the first phase, the study is conducted on feasibility of development of techniques for digging high-temperature beds under a temperature condition of 250 degrees C, where the rotary table type digger is mainly studied. It is most widely used for digging oil wells as well as geothermal wells. The current rotary table B type digger is studied as the equipment serviceable at 250 degrees C as the target temperature level for the moment for digging high-temperature beds. The studied items include the problems involved in the digger body, pipes, bits and other members, and also measures to expand its possibility. Also studied/surveyed are applicability of the new digging techniques now under development to geothermal wells, and techniques for fracturing high-temperature rocks. This report summarizes to help select the methods desired to be developed in the future, and plan development of the digging systems. (NEDO)

  13. 3D Virtual Dig: a 3D Application for Teaching Fieldwork in Archaeology

    Directory of Open Access Journals (Sweden)

    Paola Di Giuseppantonio Di Franco

    2012-12-01

    Full Text Available Archaeology is a material, embodied discipline; communicating this experience is critical to student success. In the context of lower-division archaeology courses, the present study examines the efficacy of 3D virtual and 2D archaeological representations of digs. This presentation aims to show a 3D application created to teach the archaeological excavation process to freshmen students. An archaeological environment was virtually re-created in 3D, and inserted in a virtual reality software application that allows users to work with the reconstructed excavation area. The software was tested in class for teaching the basics of archaeological fieldwork. The application interface is user-friendly and especially easy for 21st century students. The study employed a pre-survey, post-test, and post-survey design, used to understand the students' previous familiarity with archaeology, and test their awareness after the use of the application. Their level of knowledge was then compared with that of those students who had accessed written material only. This case-study demonstrates how a digital approach to laboratory work can positively affect student learning. Increased abilities to complete ill-defined problems (characteristic of the high-order thinking in the field, can, in fact, be demonstrated. 3D Virtual reconstruction serves, then, as an important bridge from traditional coursework to fieldwork.

  14. Archaeological and Numismatic Findings from Dig CLXXXV at Bolgar Fortifi ed Settlement

    Directory of Open Access Journals (Sweden)

    Bugarchev Alexey I.

    2016-12-01

    Full Text Available The authors analyze new numismatic finds from Bolgar fortified settlement, dig CLXXXV, which was excavated in 2013. All numismatic findings (240 coins can be divided into three groups: stray silver coins – 23 pieces dating to the 13th – 14th centuries, a hoard of silver coins – 37 dangs of the 14th century, and copper dinars and pools of the 13th – 14th centuries – 180 pieces. Most of these were coined by the mint in Bolgar (Bolgar al-Makhrusa – 82 pieces. Other coins represents mints in Saray (Saray al-Makhrusa, Saray al-Dzhadid, Gulistan, the Crimea and Mokhsha. Chronologically, most coins are dated by the middle of the 13th century – 44 copies, and by 1330s –1340s – 91 pieces. Although the structure of the hoard is typical for Bulgar hoards of the 14th century, this one is particularly valuable for the fact that its exact location is known precisely. Numerous copper coins allow undertaking a metrological analysis for each group – the copper dinars of the 13th century and the pools of the 1320s – early 1360s. The youngest dang in the hoard dates to 1362–1363, as the pools of Hyzr Khan do. This made the authors to infer that the monetary circulation in this part of the city stopped in the first half of the 1360s.

  15. Association between meteor showers and asteroids using multivariate criteria

    Science.gov (United States)

    Dumitru, B. A.; Birlan, M.; Popescu, M.; Nedelcu, D. A.

    2017-10-01

    Context. Meteoroid streams are fragments of matter produced by comets or asteroids which intersects the orbit of Earth. Meteor showers are produced when Earth intersects these streams of matter. The discoveries of active asteroids and extinct comets open a new view of the relation between these objects as possible parent bodies at the origin of meteor showers. Aims: The aim of this work is to identify the asteroids that can produce or re-populate meteoroid streams by determining the similarity of their orbits and orbital evolution over 10 000 yr. Methods: The identification was carried out by evaluating several well known D-criteria metrics, the orbits being taken from the IAU Meteor Data Center database and from IAU Minor Planet Center. Finally, we analyzed the physical properties and the orbital stability (in the Lyapunov time sense) of the candidates as well as their possible relationship with meteorites. Results: 206 near-Earth asteroids (NEAs) were associated as possible parent bodies with 28 meteor showers, according to at least two of the criterion used. 50 of them satisfied all the criteria. Notable finds are: binary asteroid 2000UG11 associated with Andromedids (AND), while the tumbling asteroid (4179)Toutatis could be associated with October Capricornids (OCC). Other possible good candidates are 2004TG10, 2008EY5, 2010CF55, 2010TU149 and 2014OY1. These objects have low albedo, therefore can be primitive objects. Asteroid 2007LW19 which is a fast rotator and most probably has monolithic structure and so its physical characteristic does not support the association found based on the dynamical criteria.

  16. HIGH ECLIPTIC LATITUDE SURVEY FOR SMALL MAIN-BELT ASTEROIDS

    International Nuclear Information System (INIS)

    Terai, Tsuyoshi; Takahashi, Jun; Itoh, Yoichi

    2013-01-01

    Main-belt asteroids have been continuously colliding with one another since they were formed. Their size distribution is primarily determined by the size dependence of asteroid strength against catastrophic impacts. The strength scaling law as a function of body size could depend on collision velocity, but the relationship remains unknown, especially under hypervelocity collisions comparable to 10 km s –1 . We present a wide-field imaging survey at an ecliptic latitude of about 25° for investigating the size distribution of small main-belt asteroids that have highly inclined orbits. The analysis technique allowing for efficient asteroid detections and high-accuracy photometric measurements provides sufficient sample data to estimate the size distribution of sub-kilometer asteroids with inclinations larger than 14°. The best-fit power-law slopes of the cumulative size distribution are 1.25 ± 0.03 in the diameter range of 0.6-1.0 km and 1.84 ± 0.27 in 1.0-3.0 km. We provide a simple size distribution model that takes into consideration the oscillations of the power-law slope due to the transition from the gravity-scaled regime to the strength-scaled regime. We find that the high-inclination population has a shallow slope of the primary components of the size distribution compared to the low-inclination populations. The asteroid population exposed to hypervelocity impacts undergoes collisional processes where large bodies have a higher disruptive strength and longer lifespan relative to tiny bodies than the ecliptic asteroids

  17. The Chelyabinsk superbolide: a fragment of asteroid 2011 EO40?

    Science.gov (United States)

    de la Fuente Marcos, C.; de la Fuente Marcos, R.

    2013-11-01

    Bright fireballs or bolides are caused by meteoroids entering the Earth's atmosphere at high speed. Some have a cometary origin, a few may have originated within the Venus-Earth-Mars region as a result of massive impacts in the remote past but a relevant fraction is likely the result of the break-up of asteroids. Disrupted asteroids produce clusters of fragments or asteroid families and meteoroid streams. Linking a bolide to a certain asteroid family may help to understand its origin and pre-impact dynamical evolution. On 2013 February 15, a superbolide was observed in the skies near Chelyabinsk, Russia. Such a meteor could be the result of the decay of an asteroid and here we explore this possibility applying a multistep approach. First, we use available data and Monte Carlo optimization (validated using 2008 TC3 as template) to obtain a robust solution for the pre-impact orbit of the Chelyabinsk impactor (a = 1.62 au, e = 0.53, i = 3.82°, Ω = 326.41° and ω = 109.44°). Then, we use this most probable orbit and numerical analysis to single out candidates for membership in, what we call, the Chelyabinsk asteroid family. Finally, we perform N-body simulations to either confirm or reject any dynamical connection between candidates and impactor. We find reliable statistical evidence on the existence of the Chelyabinsk cluster. It appears to include multiple small asteroids and two relatively large members: 2007 BD7 and 2011 EO40. The most probable parent body for the Chelyabinsk superbolide is 2011 EO40. The orbits of these objects are quite perturbed as they experience close encounters not only with the Earth-Moon system but also with Venus, Mars and Ceres. Under such conditions, the cluster cannot be older than about 20-40 kyr.

  18. UV Reflectance of Jupiter's Moon Europa and Asteroid (16) Psyche

    Science.gov (United States)

    Becker, T. M.; Retherford, K. D.; Roth, L.; Hendrix, A.; McGrath, M. A.; Cunningham, N.; Feaga, L. M.; Saur, J.; Elkins-Tanton, L. T.; Walhund, J. E.; Molyneux, P.

    2017-12-01

    Surface reflectance observations of solar system objects in the UV are not only complimentary to longer wavelength observations for identifying surface composition, but can also reveal new and meaningful information about the surfaces of those bodies. On Europa, far-UV (FUV) spectral observations made by the Hubble Space Telescope (HST) show that the surface lacks a strong water ice absorption edge near 165 nm, which is intriguing because such a band has been detected on most icy satellites. This may suggest that radiolytic processing by Jupiter's magnetosphere has altered the surface, causing absorption at wavelengths longward of the H2O edge, masking this feature. Additionally, the FUV spectra are blue (increasing albedo with shorter wavelengths), and regions that are observed to be dark in the visible appear bright in the FUV. This spectral inversion, also observed on the Moon and some asteroids, may provide insight into the properties of the surface material and how they are processed.We also explore the UV reflectance spectra of the main belt asteroid (16) Psyche. This asteroid is believed to be the metallic remnant core of a differentiated asteroid, stripped of its mantle through collisions. However, there is speculation that the asteroid could have formed as-is from highly reduced metal-rich material near the Sun early in the formation of the solar system. Further, spectral observations in the infrared have revealed pyroxene and hydroxyl on the asteroid's surface, complicating the interpretation that (16) Psyche is a pure metallic object. Laboratory studies indicate that there are diagnostic spectral features in the UV that could be useful for determining the surface composition. We obtained HST observations of Psyche from 160 - 300 nm. Preliminary results show a featureless, red-sloped spectrum, inconsistent with significant amounts of pyroxene on the surface. We will present the spectra of Europa and the asteroid (16) Psyche and discuss the unique details

  19. Stability Limits for Rubble Pile Asteroid Shapes

    Science.gov (United States)

    Scheeres, Daniel

    2018-04-01

    The stability of rubble pile asteroids are explored analytically, using simple models for their constituent components. Specifically, we look at the stability of spherical components resting and potentially rolling on each other as a function of their relative sizes, configuration and number. This talk will present some recent results in this problem. Of specific interest is a 5:1 limit on the elongation of a rubble pile body for stability, which is interestingly the same extreme elongation found for the first interstellar object. This limit is for a rubble pile consisting of stacked spheres, resting on each other in a straight line. If there are 5 or less bodies resting on each other in this configuration, there is an interval of spin rates for which the configuration is stable. If there are 6 or more bodies stacked as such, the spin rate for it to stabilize is beyond the spin rate at which it fissions. The talk will also explore additional results for different configurations of bodies resting on each other.

  20. Un asteroide proveniente de la Luna

    Science.gov (United States)

    Tancredi, G.

    El descubrimiento de un débil objeto en movimiento por el telescopio Spacewatch (un instrumento dedicado a la búsqueda de Asteroides Cercanos a la Tierra) en 1991, ha generado una gran controversia en la comunidad planetaria. El objeto, denominado 1991 VG, tiene elementos orbitales llamativamente similares a los de la Tierra, lo que ha llevado a B. G. Marsden a aventurar:``El objeto podría ser una nave espacial en retorno (IAUC 5387)". Luego de analizar las características dinámicas de 1991 VG y las diferentes hipótesis sobre su origen, favorecemos la alternativa de que el objeto es un gran fragmento de material eyectado de la Luna durante un reciente impacto (en las últimas decenas de miles de años). El hallazgo en 1983 en la Antártida de meteoritos con composición tipo lunar, confirma la posibilidad de que material de la superficie del satélite puede ser eyectado a velocidades superiores a la de escape del sistema Tierra-Luna y alcance órbitas heliocéntricas. Los elementos orbitales de 1991 VG corresponden a los valores alcanzados por partículas que apenas escapan de la gravedad lunar y entran en órbitas heliocéntricas a través del punto Lagrangiano exterior del sistema Tierra-Sol.

  1. Discovery of a Satellite around a Near-Earth Asteroid

    Science.gov (United States)

    1997-07-01

    In the course of the major observational programme of asteroids by the Institute of Planetary Exploration of the German Aerospace Research Establishment (DLR) [1] in Berlin, two of the staff astronomers, Stefano Mottola and Gerhard Hahn , have discovered a small satellite (moon) orbiting the asteroid (3671) Dionysus. The new measurements were obtained with the DLR CCD Camera attached at the 60-cm Bochum telescope at the ESO La Silla Observatory in Chile. This is only the second known case of an asteroid with a moon. Moons and planets Until recently, natural satellites were only known around the major planets . The Moon orbits the Earth, there are two tiny moons around Mars, each of the giant planets Jupiter, Saturn, Uranus and Neptune has many more, and even the smallest and outermost, Pluto, is accompanied by one [2]. However, the new discovery now strengthens the belief of many astronomers that some, perhaps even a substantial number of the many thousands of minor planets (asteroids) in the solar system may also possess their own moons. The first discovery of a satellite orbiting an asteroid was made by the NASA Galileo spacecraft, whose imagery, obtained during a fly-by of asteroid (253) Ida in August 1993, unveiled a small moon that has since been given the name Dactyl. (3671) Dionysus: an Earth-crossing asteroid In the framework of the DLR asteroid monitoring programme, image sequences are acquired to measure an asteroid's brightness variations caused by the changing amount of sunlight reflected from the asteroid's illuminated surface as it spins, due to its irregular shape. The brightness variations may be used to derive the asteroid's rotational properties, such as speed of rotation and spin axis orientation. Asteroid Dionysus [3] was put on the observing list because it belongs to a special class of asteroids, the members of which occasionally come very close to the Earth and have a small, but non-negligible chance of colliding with our planet. Most of

  2. Comets, Asteroids, and the Origin of the Biosphere

    Science.gov (United States)

    Hoover, Richard B.

    2006-01-01

    range of temperatures in cavities and voids at different depths just beneath the crust of a comet. The possibility that liquid water may exist over a wide range of temperatures on comets significantly enhances the possibility that these bodies may harbor niches suitable for microbial communities and ecosystems. Such niches would by ideal for the growth of psychrophilic, mesophilic, and possibly even thermophilic chemolithotrophs and photoautotrophs such as the motile filamentous cyanobacteria (e.g., Calothrix, Oscillatoria, Phormidium, and Spirulina) that can grow in geothermal springs and geysers at temperatures ranging from 320K to 345K and in cold polar desert soils. This paper reviews the observational data in support of the hypothesis that liquid water can exist in permafrost-like active regions just beneath the surface of comets when near perihelion and provides additional arguments in support of the hypothesis that comets, carbonaceous meteorites, and asteroids may have played a significant role in the origin and evolution of the Biosphere and in the distribution of microbial life throughout the Solar System.

  3. Dynamical passage to approximate equilibrium shapes for spinning, gravitating rubble asteroids

    Science.gov (United States)

    Sharma, Ishan; Jenkins, James T.; Burns, Joseph A.

    2009-03-01

    Many asteroids are thought to be particle aggregates held together principally by self-gravity. Here we study — for static and dynamical situations — the equilibrium shapes of spinning asteroids that are permitted for rubble piles. As in the case of spinning fluid masses, not all shapes are compatible with a granular rheology. We take the asteroid to always be an ellipsoid with an interior modeled as a rigid-plastic, cohesion-less material with a Drucker-Prager yield criterion. Using an approximate volume-averaged procedure, based on the classical method of moments, we investigate the dynamical process by which such objects may achieve equilibrium. We first collapse our dynamical approach to its statical limit to derive regions in spin-shape parameter space that allow equilibrium solutions to exist. At present, only a graphical illustration of these solutions for a prolate ellipsoid following the Drucker-Prager failure law is available [Sharma, I., Jenkins, J.T., Burns, J.A., 2005a. Bull. Am. Astron. Soc. 37, 643; Sharma, I., Jenkins, J.T., Burns, J.A., 2005b. Equilibrium shapes of ellipsoidal soil asteroids. In: García-Rojo, R., Hermann, H.J., McNamara, S. (Eds.), Proceedings of the 5th International Conference on Micromechanics of Granular Media, vol. 1. A.A. Balkema, UK; Holsapple, K.A., 2007. Icarus 187, 500-509]. Here, we obtain the equilibrium landscapes for general triaxial ellipsoids, as well as provide the requisite governing formulae. In addition, we demonstrate that it may be possible to better interpret the results of Richardson et al. [Richardson, D.C., Elankumaran, P., Sanderson, R.E., 2005. Icarus 173, 349-361] within the context of a Drucker-Prager material. The graphical result for prolate ellipsoids in the static limit is the same as those of Holsapple [Holsapple, K.A., 2007. Icarus 187, 500-509] because, when worked out, his final equations will match ours. This is because, though the formalisms to reach these expressions differ, in statics

  4. Polarimetric survey of main-belt asteroids. V. The unusual polarimetric behavior of V-type asteroids

    Science.gov (United States)

    Gil-Hutton, R.; López-Sisterna, C.; Calandra, M. F.

    2017-03-01

    Aims: We present the results of a polarimetric survey of main-belt asteroids at Complejo Astronómico El Leoncito (CASLEO), San Juan, Argentina. The aims of this survey are to increase the database of asteroid polarimetry, to estimate diversity in polarimetric properties of asteroids that belong to different taxonomic classes, and to search for objects that exhibit anomalous polarimetric properties. Methods: The data were obtained using the CASPROF and CASPOL polarimeters at the 2.15 m telescope. The CASPROF polarimeter is a two-hole aperture polarimeter with rapid modulation and CASPOL is a polarimeter based on a CCD detector, which allows us to observe fainter objects with better signal-to-noise ratio. Results: The survey began in 1995 and data on a large sample of asteroids were obtained until 2012. A second period began in 2013 using a polarimeter with a more sensitive detector in order to study small asteroids, families, and special taxonomic groups. We obtained 55 polarimetric measurements for 28 V-type main belt asteroids, all of them polarimetrically observed for the first time. The data obtained in this survey let us find polarimetric parameters for (1459) Magnya and for a group of 11 small V-type objects with similar polarimetric behavior. These polarization curves are unusual since they show a shallow minimum and a small inversion angle in comparison with (4) Vesta, although they have a steeper slope at α0. This polarimetric behavior could be explained by differences in the regoliths of these asteroids. The observations of (2579) Spartacus, and perhaps also (3944) Halliday, indicate a inversion angle larger than 24-25°. Based on observations carried out at the Complejo Astronómico El Leoncito, operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the National Universities of La Plata, Córdoba, and San Juan.

  5. Automated Classification of Asteroids into Families at Work

    Science.gov (United States)

    Knežević, Zoran; Milani, Andrea; Cellino, Alberto; Novaković, Bojan; Spoto, Federica; Paolicchi, Paolo

    2014-07-01

    We have recently proposed a new approach to the asteroid family classification by combining the classical HCM method with an automated procedure to add newly discovered members to existing families. This approach is specifically intended to cope with ever increasing asteroid data sets, and consists of several steps to segment the problem and handle the very large amount of data in an efficient and accurate manner. We briefly present all these steps and show the results from three subsequent updates making use of only the automated step of attributing the newly numbered asteroids to the known families. We describe the changes of the individual families membership, as well as the evolution of the classification due to the newly added intersections between the families, resolved candidate family mergers, and emergence of the new candidates for the mergers. We thus demonstrate how by the new approach the asteroid family classification becomes stable in general terms (converging towards a permanent list of confirmed families), and in the same time evolving in details (to account for the newly discovered asteroids) at each update.

  6. A retrograde co-orbital asteroid of Jupiter.

    Science.gov (United States)

    Wiegert, Paul; Connors, Martin; Veillet, Christian

    2017-03-29

    Recent theoretical work in celestial mechanics has revealed that an asteroid may orbit stably in the same region as a planet, despite revolving around the Sun in the sense opposite to that of the planet itself. Asteroid 2015 BZ 509 was discovered in 2015, but with too much uncertainty in its measured orbit to establish whether it was such a retrograde co-orbital body. Here we report observations and analysis that demonstrates that asteroid 2015 BZ 509 is indeed a retrograde co-orbital asteroid of the planet Jupiter. We find that 2015 BZ 509 has long-term stability, having been in its current, resonant state for around a million years. This is long enough to preclude precise calculation of the time or mechanism of its injection to its present state, but it may be a Halley-family comet that entered the resonance through an interaction with Saturn. Retrograde co-orbital asteroids of Jupiter and other planets may be more common than previously expected.

  7. PRODUCTION OF NEAR-EARTH ASTEROIDS ON RETROGRADE ORBITS

    International Nuclear Information System (INIS)

    Greenstreet, S.; Gladman, B.; Ngo, H.; Granvik, M.; Larson, S.

    2012-01-01

    While computing an improved near-Earth object (NEO) steady-state orbital distribution model, we discovered in the numerical integrations the unexpected production of retrograde orbits for asteroids that had originally exited from the accepted main-belt source regions. Our model indicates that ∼0.1% (a factor of two uncertainty) of the steady-state NEO population (perihelion q < 1.3 AU) is on retrograde orbits. These rare outcomes typically happen when asteroid orbits flip to a retrograde configuration while in the 3:1 mean-motion resonance with Jupiter and then live for ∼0.001 to 100 Myr. The model predicts, given the estimated near-Earth asteroid (NEA) population, that a few retrograde 0.1-1 km NEAs should exist. Currently, there are two known MPC NEOs with asteroidal designations on retrograde orbits which we therefore claim could be escaped asteroids instead of devolatilized comets. This retrograde NEA population may also answer a long-standing question in the meteoritical literature regarding the origin of high-strength, high-velocity meteoroids on retrograde orbits.

  8. Three dimensional modelling for the target asteroid of HAYABUSA

    Science.gov (United States)

    Demura, H.; Kobayashi, S.; Asada, N.; Hashimoto, T.; Saito, J.

    Hayabusa program is the first sample return mission of Japan. This was launched at May 9 2003, and will arrive at the target asteroid 25143 Itokawa on June 2005. The spacecraft has three optical navigation cameras, which are two wide angle ones and a telescopic one. The telescope with a filter wheel was named AMICA (Asteroid Multiband Imaging CAmera). We are going to model a shape of the target asteroid by this telescope; expected resolution: 1m/pixel at 10 km in distanc, field of view: 5.7 squared degrees, MPP-type CCD with 1024 x 1000 pixels. Because size of the Hayabusa is about 1x1x1 m, our goal is shape modeling with about 1m in precision on the basis of a camera system with scanning by rotation of the asteroid. This image-based modeling requires sequential images via AMICA and a history of distance between the asteroid and Hayabusa provided by a Laser Range Finder. We established a system of hierarchically recursive search with sub-pixel matching of Ground Control Points, which are picked up with Susan Operator. The matched dataset is restored with a restriction of epipolar geometry, and the obtained a group of three dimensional points are converted to a polygon model with Delaunay Triangulation. The current status of our development for the shape modeling is displayed.

  9. Dust arcs in the region of Jupiter's Trojan asteroids

    Science.gov (United States)

    Liu, Xiaodong; Schmidt, Jürgen

    2018-01-01

    Aims: The surfaces of the Trojan asteroids are steadily bombarded by interplanetary micrometeoroids, which releases ejecta of small dust particles. These particles form the faint dust arcs that are associated with asteroid clouds. Here we analyze the particle dynamics and structure of the arc in the region of the L4 Trojan asteroids. Methods: We calculate the total cross section of the L4 Trojan asteroids and the production rate of dust particles. The motion of the particles is perturbed by a variety of forces. We simulate the dynamical evolution of the dust particles, and explore the overall features of the Trojan dust arc. Results: The simulations show that the arc is mainly composed of grains in the size range 4-10 microns. Compared to the L4 Trojan asteroids, the dust arc is distributed more widely in the azimuthal direction, extending to a range of [30, 120] degrees relative to Jupiter. The peak number density does not develop at L4. There exist two peaks that are azimuthally displaced from L4.

  10. Candidate Binary Trojan and Hilda Asteroids from Rotational Light Curves

    Science.gov (United States)

    Sonnett, Sarah M.; Mainzer, Amy K.; Grav, Tommy; Masiero, Joseph R.; Bauer, James M.; Kramer, Emily A.

    2017-10-01

    Jovian Trojans (hereafter, Trojans) are asteroids in stable orbits at Jupiter's L4 and L5 Lagrange points, and Hilda asteroids are inwards of the Trojans in 3:2 mean-motion resonance with Jupiter. Due to their special dynamical properties, observationally constraining the formation location and dynamical histories of Trojans and HIldas offers key input for giant planet migration models. A fundamental parameter in assessing formation location is the bulk density - with low-density objects associated with an ice-rich formation environment in the outer solar system and high-density objects typically linked to the warmer inner solar system. Bulk density can only be directly measured during a close fly-by or by determining the mutual orbits of binary asteroid systems. With the aim of determining densities for a statistically significant sample of Trojans and Hildas, we are undertaking an observational campaign to confirm and characterize candidate binary asteroids published in Sonnett et al. (2015). These objects were flagged as binary candidates because their large NEOWISE brightness variations imply shapes so elongated that they are not likely explained by a singular equilibrium rubble pile and instead may be two elongated, gravitationally bound asteroids. We are obtaining densely sampled rotational light curves of these possible binaries to search for light curve features diagnostic of binarity and to determine the orbital properties of any confirmed binary systems by modeling the light curve. We compare the We present an update on this follow-up campaign and comment on future steps.

  11. Hayabusa2 Sampler: Collection of Asteroidal Surface Material

    Science.gov (United States)

    Sawada, Hirotaka; Okazaki, Ryuji; Tachibana, Shogo; Sakamoto, Kanako; Takano, Yoshinori; Okamoto, Chisato; Yano, Hajime; Miura, Yayoi; Abe, Masanao; Hasegawa, Sunao; Noguchi, Takaaki

    2017-07-01

    Japan Aerospace Exploration Agency (JAXA) launched the asteroid exploration probe "Hayabusa2" in December 3rd, 2014, following the 1st Hayabusa mission. With technological and scientific improvements from the Hayabusa probe, we plan to visit the C-type asteroid 162137 Ryugu (1999 JU3), and to sample surface materials of the C-type asteroid that is likely to be different from the S-type asteroid Itokawa and contain more pristine materials, including organic matter and/or hydrated minerals, than S-type asteroids. We developed the Hayabusa2 sampler to collect a minimum of 100 mg of surface samples including several mm-sized particles at three surface locations without any severe terrestrial contamination. The basic configuration of the sampler design is mainly as same as the 1st Hayabusa (Yano et al. in Science, 312(5778):1350-1353, 2006), with several minor but important modifications based on lessons learned from the Hayabusa to fulfill the scientific requirements and to raise the scientific value of the returned samples.

  12. Human spaceflight and an asteroid redirect mission: Why?

    Science.gov (United States)

    Burchell, M. J.

    2014-08-01

    The planning of human spaceflight programmes is an exercise in careful rationing of a scarce and expensive resource. Current NASA plans are to develop the new capability for human-rated launch into space to replace the Space Transportation System (STS), more commonly known as the Space Shuttle, combined with a heavy lift capability, and followed by an eventual Mars mission. As an intermediate step towards Mars, NASA proposes to venture beyond Low Earth Orbit to cis-lunar space to visit a small asteroid which will be captured and moved to lunar orbit by a separate robotic mission. The rationale for this and how to garner support from the scientific community for such an asteroid mission are discussed. Key points that emerge are that a programme usually has greater legitimacy when it emerges from public debate, mostly via a Presidential Commission, a report by the National Research Council or a Decadal Review of science goals etc. Also, human spaceflight missions need to have support from a wide range of interested communities. Accordingly, an outline scientific case for a human visit to an asteroid is made. Further, it is argued here that the scientific interest in an asteroid mission needs to be included early in the planning stages, so that the appropriate capabilities (here the need for drilling cores and carrying equipment to, and returning samples from, the asteroid) can be included.

  13. Observing the variation of asteroid thermal inertia with heliocentric distance

    Science.gov (United States)

    Rozitis, B.; Green, S. F.; MacLennan, E.; Emery, J. P.

    2018-06-01

    Thermal inertia is a useful property to characterize a planetary surface, since it can be used as a qualitative measure of the regolith grain size. It is expected to vary with heliocentric distance because of its dependence on temperature. However, no previous investigation has conclusively observed a change in thermal inertia for any given planetary body. We have addressed this by using NEOWISE data and the Advanced Thermophysical Model to study the thermophysical properties of the near-Earth asteroids (1036) Ganymed, (1580) Betulia, and (276 049) 2002 CE26 as they moved around their highly eccentric orbits. We confirm that the thermal inertia values of Ganymed and 2002 CE26 do vary with heliocentric distance, although the degree of variation observed depends on the spectral emissivity assumed in the thermophysical modelling. We also confirm that the thermal inertia of Betulia did not change for three different observations obtained at the same heliocentric distance. Depending on the spectral emissivity, the variations for Ganymed and 2002 CE26 are potentially more extreme than that implied by theoretical models of heat transfer within asteroidal regoliths, which might be explained by asteroids having thermal properties that also vary with depth. Accounting for this variation reduces a previously observed trend of decreasing asteroid thermal inertia with increasing size, and suggests that the surfaces of small and large asteroids could be much more similar than previously thought. Furthermore, this variation can affect Yarkovsky orbital drift predictions by a few tens of per cent.

  14. Asteroid Origins Satellite (AOSAT): Science in a CubeSat Centrifuge

    Science.gov (United States)

    Perera, V.; Cotto-Figueroa, D.; Noviello, J.; Asphaug, E.; Morris, M.

    2015-01-01

    Both the study of primary accretion and the surface properties of asteroids are important for the field of planetary science. The Asteroid Origins Satellite (AOSAT) will help study these subjects by creating a long duration microgravity laboratory.

  15. Orbits of the Asteroids Discovered at the Molėtai Observatory in 2000–2004

    Directory of Open Access Journals (Sweden)

    Černis K.

    2014-12-01

    Full Text Available The paper presents statistics of the asteroids observed and discovered at the Molėtai Observatory, Lithuania in 2000–2004 within the project for astrometric observations of the near-Earth objects (NEOs, the main belt asteroids and comets. CCD observations of asteroids were obtained with the 35/51 cm Maksutov-type meniscus telescope and the 1.65 m Ritchey-Chretien reflector. In the Minor Planet Circulars and the Minor Planet Electronic Circulars (2000–2004 we published 6629 astrometric positions of 1114 asteroids. Among them 78 were newly discovered asteroids at Molėtai, a few NEOs were found by our team independently. For the 67 asteroids discovered at Molėtai the precise orbits were calculated. Because of small number of observations, a few asteroids have low-precision orbits and some asteroids have been lost. For seven objects we present their ephemerides for 2015.

  16. Rotational rates of very small asteroids - 123 Brunhild, 376 Geometria, 437 Rhodia and 1224 Fantasia

    Science.gov (United States)

    Barucci, M. A.; di Martino, M.

    1984-07-01

    This paper presents observations of four small main belt asteroids (D Geometria, an accurate rotational period was determined. For the other two asteroids, 437 Rhodia and 1224 Fantasia, only tentative periods are suggested.

  17. Dig protection and deep installation as risk reducing measures when laying 10 bar PE piping; Graevskydd ock djupfoerlaeggning som riskreducerande aatgaerder vid foerlaeggning av 10 bars PE-roersystem

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Linda [SP Sveriges Tekniska Forskningsinstitut, Boraas (Sweden)

    2011-07-15

    The development of polyethylene pipes enables gas distribution with a pressure up to 10 bars. According to current Swedish legislation, the safety distance is the same for gas conduit with 10 bars as for pipe conduits made of steel with a pressure of 80 bars. To be able to reduce the safety distance, actions must be taken to ensure the safety in general, and for the excavator operators in particular, who are usually closest to the conduits when an accident may happen. Excavator operators react on visual impression or a feeling that something deviates from the normal or the expected conditions. The visual impression could be mixed soils or filling materials used around the pipes indicating that excavation activities have occurred before. Marker tape laid in the right manner seems to warn some excavator operators, but far from all. The incident frequency varies considerably between different excavator operators. The excavator operators often blame the network map or incorrect marking. Network owners deny this reason. Excavating incidents mostly occurs across the conduits and most often with smaller excavators than 17 tonnes. During 2010, three excavation related incidents involving natural gas pipelines and 26 involving town gas, were reported to Energigas Sverige. During 2009, the corresponding figures were instead seven incidents with natural gas and 17 with town gas and during 2008 there were six incidences related to natural gas pipelines and only two involved town gas. None of the reported incidents during the three years have led to either injury or death. Heavy concrete plates were used earlier which demanded machines and took much longer to install, but the new polyethylene plates can be installed by hand. Tests performed together with Gas de France and others showed that, if an excavator hits a concrete plate, it is not certain that the digging is stopped. The investigations showed that the digging was stopped immediately when protective polyethylene plates

  18. Galileo Photometry of Asteroid 951 Gaspra

    Science.gov (United States)

    Helfenstein, P.; Veverka, J.; Thomas, P.C.; Simonelli, D.P.; Lee, P.; Klaasen, K.; Johnson, T.V.; Breneman, H.; Head, J.W.; Murchie, S.; Fanale, F.; Robinson, M.; Clark, B.; Granahan, J.; Garbeil, H.; McEwen, A.S.; Kirk, R.L.; Davies, M.; Neukum, G.; Mottola, S.; Wagner, R.; Belton, M.; Chapman, C.; Pilcher, C.

    1994-01-01

    Galileo images of Gaspra make it possible for the first time to determine a main-belt asteroid's photometric properties accurately by providing surface-resolved coverage over a wide range of incidence and emission angles and by extending the phase angle coverage to phases not observable from Earth. We combine Earth-based telescopic photometry over phase angles 2?? ??? ?? ??? 25?? with Galileo whole-disk and disk-resolved data at 33?? ??? ?? ??? 51?? to derive average global photometric properties in terms of Hapke's photometric model. The microscopic texture and particle phase-function behavior of Gaspra's surface are remarkably like those of other airless rocky bodies such as the Moon. The macroscopic surface roughness parameter, ??̄ = 29??, is slightly larger than that reported for typical lunar materials. The particle single scattering albedo, ??́0 = 0.36 ?? 0.07, is significantly larger than for lunar materials, and the opposition surge amplitude, B0 = 1.63 ?? 0.07, is correspondingly smaller. We determine a visual geometric albedo pv = 0.22 ?? 0.06 for Gaspra, in close agreement with pv = 0.22 ?? 0.03 estimated from Earth-based observations. Gaspra's phase integral is 0.47, and the bolometric Bond albedo is estimated to be 0.12 ?? 0.03. An albedo map derived by correcting Galileo images with our average global photometric function reveals subdued albedo contrasts of ??10% or less over Gaspra's northern hemisphere. Several independent classification algorithms confirm the subtle spectral heterogeneity reported earlier (S. Mottola, M. DiMartino, M. Gonano-Beurer, H. Hoffman, and G. Neukum, 1993, Asteroids, Comets, Meteors, pp. 421-424; M. J. S. Belton et al., 1992, Science 257, 1647-1652). Whole-disk colors (0.41 ??? ?? ??? 0.99 ??m) vary systematically with longitude by about ??5%, but color differences as large as 30% occur locally. Colors vary continuously between end-member materials whose areal distribution correlates with regional topography. Infrared

  19. Ultraviolet Spectroscopy of Asteroid(4) Vesta

    Science.gov (United States)

    Li, Jian-Yang; Bodewits, Dennis; Feaga, Lori M.; Landsman, Wayne; A'Hearn, Michael F.; Mutchler, Max J.; Russell, Christopher T.; McFadden, Lucy A.; Raymond, Carol A.

    2011-01-01

    We report a comprehensive review of the UV-visible spectrum and rotational lightcurve of Vesta combining new observations by Hubble Space Telescope and Swift with archival International Ultraviolet Explorer observations. The geometric albedos of Vesta from 220 nm to 953 nm arc derived by carefully comparing these observations from various instruments at different times and observing geometries. Vesta has a rotationally averaged geometric albedo of 0.09 at 250 nm, 0.14 at 300 nm, 0.26 at 373 nm, 0.38 at 673 nm, and 0.30 at 950 nm. The linear spectral slope in the ultraviolet displays a sharp minimum ncar sub-Earth longitude of 20deg, and maximum in the eastern hemisphere. This is completely consistent with the distribution of the spectral slope in the visible wavelength. The uncertainty of the measurement in the ultraviolet is approx.20%, and in the visible wavelengths better than 10%. The amplitude of Vesta's rotational lightcurves is approx.10% throughout the range of wavelengths we observed, but is smaller at 950 nm (approx.6%) ncar the 1-micron mafic band center. Contrary to earlier reports, we found no evidence for any difference between the phasing of the ultraviolet and visible/ncar-infrared lightcurves with respect to sub-Earth longitude. Vesta's average spectrum between 220 and 950 nm can well be described by measured reflectance spectra of fine particle howardite-like materials of basaltic achondrite meteorites. Combining this with the in-phase behavior of the ultraviolet, visible. and ncar-infrared lightcurves, and the spectral slopes with respect to the rotational phase, we conclude that there is no global ultraviolet/visible reversal on Vesta. Consequently, this implies lack of global space weathering on Vesta. Keyword,: Asteroid Vesta; Spectrophotometry; Spectroscopy; Ultraviolet observations; Hubble Space Telescope observations

  20. Trojan and Hilda asteroid lightcurves. I - Anomalously elongated shapes among Trojans (and Hildas?)

    Science.gov (United States)

    Hartmann, William K.; Binzel, Richard P.; Tholen, David J.; Cruikshank, Dale P.; Goguen, Jay

    1988-01-01

    A comparison of the available sample of lightcurves for 26 Trojan and Hilda asteroids with belt asteroid lightcurves shows the former to be distinguished by a higher incidence of high amplitudes rgan belt asteroids of comparable size, suggesting more elongated shapes; they currently have, moreover, only a few percent of the main-belt asteroids' collision frequency. A more modest collisional evolution that may have affected the relative degree of fragmentation of these bodies, and thus their shapes, is inferred.

  1. An Investigation of the Ranges of Validity of Asteroid Thermal Models for Near-Earth Asteroid Observations

    Science.gov (United States)

    Mommert, M.; Jedicke, R.; Trilling, D. E.

    2018-02-01

    The majority of known asteroid diameters are derived from thermal-infrared observations. Diameters are derived using asteroid thermal models that approximate their surface temperature distributions and compare the measured thermal-infrared flux with model-dependent predictions. The most commonly used thermal model is the Near-Earth Asteroid Thermal Model (NEATM), which is usually perceived as superior to other models like the Fast-Rotating Model (FRM). We investigate the applicability of the NEATM and the FRM to thermal-infrared observations of Near-Earth Objects using synthetic asteroids with properties based on the real Near-Earth Asteroid (NEA) population. We find the NEATM to provide more accurate diameters and albedos than the FRM in most cases, with a few exceptions. The modeling results are barely affected by the physical properties of the objects, but we find a large impact of the solar phase angle on the modeling results. We conclude that the NEATM provides statistically more robust diameter estimates for NEAs observed at solar phase angles less than ∼65°, while the FRM provides more robust diameter estimates for solar phase angles greater than ∼65°. We estimate that <5% of all NEA diameters and albedos derived up to date are affected by systematic effects that are of the same order of magnitude as the typical thermal model uncertainties. We provide statistical correction functions for diameters and albedos derived using the NEATM and FRM as a function of solar phase angle.

  2. Results of the 2017 Mexican Asteroid Photometry Campaign - Part 1

    Science.gov (United States)

    Sada, Pedro; Loera-Gonzalez, Pablo; Olguin, Lorenzo; Saucedo-Morales, Julio C.; Ayala-Gómez, Sandra A.; Garza, Jaime R.

    2018-04-01

    We report the results for the first semester of the 2017 Mexican Asteroid Photometry Campaign. Asteroid 1218 Aster (synodic period of 3.1581 ± 0.0002 h and amplitude of 0.35 mag) was well observed and showed slight variations of its lightcurve at the end of the seven week observing window. An uncertain, but long, period of 93.23 ± 0.02 h and amplitude of 0.36 mag were estimated for 2733 Hamina from sparse data. Asteroid 8443 Svecica was also well observed and yielded a period of 20.9905 ± 0.0015 h and amplitude of 0.65 mag. Observations of NEA (143404) 2003 BD44 also resulted in an uncertain and long period of 78.617 ± 0.009 h and amplitude of 0.66 mag with a sparsely covered lightcurve.

  3. Asteroid Observations with NCSFCT’s AZT-8 Telescope

    Directory of Open Access Journals (Sweden)

    Kozhukhov, O.M.

    2017-01-01

    Full Text Available The asteroid observations of the small Solar System bodies were carried out with the AZT-8 telescope (D=0.7 m, f/4 of the National Center of Space Facilities Control and Testing (NCSFCT during 2010-2013. The telescope is located near Yevpatoria, the observatory code according IAU is B17. The observational program included perturbed main belt asteroids and NEO’s for the GAIA FUN-SSO Company. The MPC database contains more than 4500 asteroids positions and magnitudes obtained during this period at AZT-8 telescope. The article presents analysis of the positional accuracy of B17 observations obtained from the comparison with the JPL HORIZONS ephemeris, and data from AstDyS-2 and NEODyS-2 web services.

  4. A New Equilibrium State for Singly Synchronous Binary Asteroids

    Science.gov (United States)

    Golubov, Oleksiy; Unukovych, Vladyslav; Scheeres, Daniel J.

    2018-04-01

    The evolution of rotation states of small asteroids is governed by the Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) effect, nonetheless some asteroids can stop their YORP evolution by attaining a stable equilibrium. The same is true for binary asteroids subjected to the binary YORP (BYORP) effect. Here we discuss a new type of equilibrium that combines these two, which is possible in a singly synchronous binary system. This equilibrium occurs when the normal YORP, the tangential YORP, and the BYORP compensate each other, and tidal torques distribute the angular momentum between the components of the system and dissipate energy. If unperturbed, such a system would remain singly synchronous in perpetuity with constant spin and orbit rates, as the tidal torques dissipate the incoming energy from impinging sunlight at the same rate. The probability of the existence of this kind of equilibrium in a binary system is found to be on the order of a few percent.

  5. Near-field effects of asteroid impacts in deep water

    Energy Technology Data Exchange (ETDEWEB)

    Gisler, Galen R [Los Alamos National Laboratory; Weaver, Robert P [Los Alamos National Laboratory; Gittings, Michael L [Los Alamos National Laboratory

    2009-06-11

    Our previous work has shown that ocean impacts of asteroids below 500 m in diameter do not produce devastating long-distance tsunamis. Nevertheless, a significant portion of the ocean lies close enough to land that near-field effects may prove to be the greatest danger from asteroid impacts in the ocean. Crown splashes and central jets that rise up many kilometres into the atmosphere can produce, upon their collapse, highly non-linear breaking waves that could devastate shorelines within a hundred kilometres of the impact site. We present illustrative calculations, in two and three dimensions, of such impacts for a range of asteroid sizes and impact angles. We find that, as for land impacts, the greatest dangers from oceanic impacts are the short-term near-field, and long-term atmospheric effects.

  6. Asteroid body-fixed hovering using nonideal solar sails

    International Nuclear Information System (INIS)

    Zeng, Xiang-Yuan; Jiang, Fang-Hua; Li, Jun-Feng

    2015-01-01

    The problem of body-fixed hovering over an asteroid using a compact form of nonideal solar sails with a controllable area is investigated. Nonlinear dynamic equations describing the hovering problem are constructed for a spherically symmetric asteroid. Numerical solutions of the feasible region for body-fixed hovering are obtained. Different sail models, including the cases of ideal, optical, parametric and solar photon thrust, on the feasible region is studied through numerical simulations. The influence of the asteroid spinning rate and the sail area-to-mass ratio on the feasible region is discussed. The required orientations for the sail and their corresponding variable lightness numbers are given for different hovering radii to identify the feasible region of the body-fixed hovering. An attractive scenario for a mission is introduced to take advantage of solar sail hovering. (paper)

  7. OBSERVED ASTEROID SURFACE AREA IN THE THERMAL INFRARED

    Energy Technology Data Exchange (ETDEWEB)

    Nugent, C. R. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Mainzer, A.; Masiero, J.; Bauer, J.; Kramer, E.; Sonnett, S. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Wright, E. L. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Grav, T. [Planetary Science Institute, Tucson, AZ (United States)

    2017-02-01

    The rapid accumulation of thermal infrared observations and shape models of asteroids has led to increased interest in thermophysical modeling. Most of these infrared observations are unresolved. We consider what fraction of an asteroid’s surface area contributes the bulk of the emitted thermal flux for two model asteroids of different shapes over a range of thermal parameters. The resulting observed surface in the infrared is generally more fragmented than the area observed in visible wavelengths, indicating high sensitivity to shape. For objects with low values of the thermal parameter, small fractions of the surface contribute the majority of thermally emitted flux. Calculating observed areas could enable the production of spatially resolved thermal inertia maps from non-resolved observations of asteroids.

  8. Samples of Asteroid Surface Ponded Deposits in Chondritic Meteorites

    Science.gov (United States)

    Zolensky, M. E.; Lee, R.; Le, L.

    2004-01-01

    One of the many unexpected observations of asteroid 433 Eros by the Near Earth Asteroid Rendezvous (NEAR) mission was the many ponds of fine-grained materials [1-3]. The ponds have smooth surfaces, and define equipotential surfaces up to 10's of meters in diameter [4]. The ponds have a uniformly sub-cm grain size and appear to be cohesive or indurated to some degree, as revealed by slumping. The ponds appear to be concentrated within 30 degrees of the equator of Eros, where gravity is lowest. There is some insight into the mineralogy and composition of the ponds surfaces from NEAR spectroscopy [2,4,5,6]. Compared to the bulk asteroid, ponds: (1) are distinctly bluer (high 550/760 nm ratio), (2) have a deeper 1um mafic band, (3) have reflectance elevated by 5%.

  9. A Cubesat Asteroid Mission: Propulsion Trade-offs

    Science.gov (United States)

    Landis, Geoffrey A.; Oleson, Steven R.; McGuire, Melissa L.; Bur, Michael J.; Burke, Laura M.; Fittje, James E.; Kohout, Lisa L.; Fincannon, James; Packard, Thomas W.; Martini, Michael C.

    2014-01-01

    A conceptual design was performed for a 6-U cubesat for a technology demonstration to be launched on the NASA Space Launch System (SLS) test launch EM-1, to be launched into a free-return translunar trajectory. The mission purpose was to demonstrate use of electric propulsion systems on a small satellite platform. The candidate objective chosen was a mission to visit a Near-Earth asteroid. Both asteroid fly-by and asteroid rendezvous missions were analyzed. Propulsion systems analyzed included cold-gas thruster systems, Hall and ion thrusters, incorporating either Xenon or Iodine propellant, and an electrospray thruster. The mission takes advantage of the ability of the SLS launch to place it into an initial trajectory of C3=0.

  10. Monocultivo de eucalipto e consórcio com sesbânia: crescimento inicial em cavas de extração de argila Eucalyptus monocropping and intercropped with sesbania: initial growth in clay mining diggings

    Directory of Open Access Journals (Sweden)

    Anderson Ribeiro Santiago

    2009-02-01

    Full Text Available O consórcio de eucalipto com sesbânia na reabilitação de cavas de extração de argila pode representar uma forma de uso com benefícios ecológicos e econômicos, tendo em vista a sub-utilização a que essas cavas estão sendo submetidas. Este trabalho teve por objetivo avaliar a sobrevivência, o crescimento inicial e características fisiológicas de Eucalyptus camaldulensis, E. tereticornis, E. robusta e E. pellita, em monocultivos e plantios consorciados com Sesbania virgata. Foram instalados dois experimentos (monocultivo e plantio consorciado, numa cava de extração de argila, segundo o delineamento em blocos casualizados com quatro repetições. Os plantios consorciados favoreceram a sobrevivência das espécies. Os eucaliptos no monocultivo apresentaram maior crescimento inicial em diâmetro do colo e em área de copa. As espécies de eucalipto responderam aos efeitos do consórcio e das podas ao longo do tempo, exceto E. tereticornis.Intercropping of Eucalyptus and sesbania for the recovery of clay mining diggings can represent ecological and economic benefits. This work aimed to evaluate survival, initial growth and physiological characteristics of Eucalyptus camaldulensis, E. tereticornis, E. robusta and E. pellita, monocropped and intercropped with Sesbania virgata. Two experiments (monocropping and intercropped were set up in a clay mining digging, arranged in a randomized block design with 4 replicates. Intercropping favored the survival of the species. Eucalyptus monocropping presented a greater initial growth in soil level diameter and canopy area. The eucalyptus species responded to the effects of intercropping and pruning, along time, except for E. tereticornis.

  11. Digging up the Past: Space, Time, and Memory in Josef Haslinger’s "Fiona und Ferdinand"

    Directory of Open Access Journals (Sweden)

    Anna Souchuk

    2015-08-01

    Full Text Available Josef Haslinger’s story "Fiona und Ferdinand" (2006 revolves around a disclosed secret in its narrator’s childhood hometown, which implicates two (deceased village elders in a decades-old rape and murder mystery long blamed on two anonymous “Russian soldiers.” The discovery of two partial skeletons locked in a bedroom trunk awakens the narrator’s memory: years before as a child, he unearthed the same skeletons after first spying a finger bone buried in a stream. The identification of the bones is central in determining the perpetrators of the rape/murder, but no one -- and in particular the narrator’s mother -- seems interested in hearing the testimony of the crime’s lone eyewitness, now an aged woman. Instead, the revelation evokes a collective effort to willfully impede any investigation into the truth, presumably as a means to maintain the town’s dual pretenses of order and respectability. "Fiona und Ferdinand" emphasizes Haslinger’s preoccupation with the Austrian failure to confront its own past, specifically via families as fundamental units of transmission and memory. In this analysis of the text, I explore Haslinger’s treatment of space, time, and memory in several ways. First, I examine how his notion of “officially sanctioned memory” intersects with a landscape that contains past and present alike. Second, I discuss how bodies, either the violated female body or the rotted skeletons Fiona and Ferdinand, are emblems that raise discussions of space, gender, and memory. Last, I consider collective memory and how it enables processes of forgetting. The reluctance to “dig up the past” is thematized in "Fiona und Ferdinand" using devices common throughout Haslinger’s oeuvre, and this paper will analyze the story through the lens of Haslinger-as-archaeologist, exploring how families, and the memories they possess, are both the key to truth and the foil to its revelation. 

  12. Can Diopatra neapolitana (Annelida: Onuphidae) regenerate body damage caused by bait digging or predation?

    Science.gov (United States)

    Pires, A.; Freitas, R.; Quintino, V.; Rodrigues, A. M.

    2012-09-01

    The regenerative ability of Diopatra neapolitana was evaluated under laboratory conditions following nine experimental amputation levels: before the beginning of the branchiae (chaetiger 3 or 4), in the branchial region, at chaetigers 10, 15, 20, 25, 30, 35 and 40 and after the branchiae, at chaetigers 45-55. Specimens amputated at the 20th chaetiger were not able to regenerate and did not survive. The posterior portion of the specimens amputated up to chaetiger 15, regenerated the anterior part but the anterior ends were unable to survive. The anterior end of the specimens amputated at and beyond the 25th chaetiger regenerated the posterior part but the posterior ends were not able to regenerate an anterior part. Percent survival was directly related to the number of branchial segments left in the regenerating specimen and reached 100% only when the specimens were amputated beyond the branchial region. These results indicate that the species has regenerative ability and should survive the loss of a few anterior chaetigers, namely caused by predation. However, the results also indicate that bait digging could impair the survival of the posterior part remaining in the tube, as usually more than 20 chaetigers are harvested by bait collectors. Regarding field-collected specimens, D. neapolitana was found regenerating a mean of 9.0 ± 2.51 chaetigers, and Diopatra marocensis 7.5 ± 1.93 chaetigers, at the anterior end. The higher percentage of field-collected specimens showing regeneration of the anterior end belonged to D. marocensis. Only very few specimens, for both species, were found regenerating the posterior part of the body.

  13. Moving on or digging deeper: Regulatory mode and interpersonal conflict resolution.

    Science.gov (United States)

    Webb, Christine E; Coleman, Peter T; Rossignac-Milon, Maya; Tomasulo, Stephen J; Higgins, E Tory

    2017-04-01

    Conflict resolution, in its most basic sense, requires movement and change between opposing motivational states. Although scholars and practitioners have long acknowledged this point, research has yet to investigate whether individual differences in the motivation for movement from state-to-state influence conflict resolution processes. Regulatory Mode Theory (RMT) describes this fundamental motivation as locomotion. RMT simultaneously describes an orthogonal motivational emphasis on assessment, a tendency for critical evaluation and comparison. We argue that this tendency, in the absence of a stronger motivation for locomotion, can obstruct peoples' propensity to reconcile. Five studies, using diverse measures and methods, found that the predominance of an individual's locomotion over assessment facilitates interpersonal conflict resolution. The first two studies present participants with hypothetical conflict scenarios to examine how chronic (Study 1) and experimentally induced (Study 2) individual differences in locomotion predominance influence the motivation to reconcile. The next two studies investigate this relation by way of participants' own conflict experiences, both through essay recall of previous conflict events (Study 3) and verbal narratives of ongoing conflict issues (Study 4). We then explore this association in the context of real-world conflict discussions between roommates (Study 5). Lastly, we examine results across these studies meta-analytically (Study 6). Overall, locomotion and assessment can inform lay theories of individual variation in the motivation to "move on" or "dig deeper" in conflict situations. We conclude by emphasizing the importance of using RMT to go beyond instrumental approaches to conflict resolution to understand fundamental individual motivations underlying its occurrence. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  14. Specialized learning in antlions (Neuroptera: Myrmeleontidae, pit-digging predators, shortens vulnerable larval stage.

    Directory of Open Access Journals (Sweden)

    Karen L Hollis

    Full Text Available Unique in the insect world for their extremely sedentary predatory behavior, pit-dwelling larval antlions dig pits, and then sit at the bottom and wait, sometimes for months, for prey to fall inside. This sedentary predation strategy, combined with their seemingly innate ability to detect approaching prey, make antlions unlikely candidates for learning. That is, although scientists have demonstrated that many species of insects possess the capacity to learn, each of these species, which together represent multiple families from every major insect order, utilizes this ability as a means of navigating the environment, using learned cues to guide an active search for food and hosts, or to avoid noxious events. Nonetheless, we demonstrate not only that sedentary antlions can learn, but also, more importantly, that learning provides an important fitness benefit, namely decreasing the time to pupate, a benefit not yet demonstrated in any other species. Compared to a control group in which an environmental cue was presented randomly vis-à-vis daily prey arrival, antlions given the opportunity to associate the cue with prey were able to make more efficient use of prey and pupate significantly sooner, thus shortening their long, highly vulnerable larval stage. Whereas "median survival time," the point at which half of the animals in each group had pupated, was 46 days for antlions receiving the Learning treatment, that point never was reached in antlions receiving the Random treatment, even by the end of the experiment on Day 70. In addition, we demonstrate a novel manifestation of antlions' learned response to cues predicting prey arrival, behavior that does not match the typical "learning curve" but which is well-adapted to their sedentary predation strategy. Finally, we suggest that what has long appeared to be instinctive predatory behavior is likely to be highly modified and shaped by learning.

  15. Evaluating Educational Resources for Inclusion in the Dig Texas Instructional Blueprints for Earth & Space Science

    Science.gov (United States)

    Jacobs, B. E.; Bohls-Graham, E.; Martinez, A. O.; Ellins, K. K.; Riggs, E. M.; Serpa, L. F.; Stocks, E.; Fox, S.; Kent, M.

    2014-12-01

    Today's instruction in Earth's systems requires thoughtful selection of curricula, and in turn, high quality learning activities that address modern Earth science. The Next Generation Science Standards (NGSS), which are intended to guide K-12 science instruction, further demand a discriminating selection process. The DIG (Diversity & Innovation in Geoscience) Texas Instructional Blueprints attempt to fulfill this practice by compiling vetted educational resources freely available online into units that are the building blocks of the blueprints. Each blueprint is composed of 9 three-week teaching units and serves as a scope and sequence for teaching a one-year Earth science course. In the earliest stages of the project, teams explored the Internet for classroom-worthy resources, including laboratory investigations, videos, visualizations, and readings, and submitted the educational resources deemed suitable for the project into the project's online review tool. Each team member evaluated the educational resources chosen by fellow team members according to a set of predetermined criteria that had been incorporated into the review tool. Resources rated as very good or excellent by all team members were submitted to the project PIs for approval. At this stage, approved resources became candidates for inclusion in the blueprint units. Team members tagged approved resources with descriptors for the type of resource and instructional strategy, and aligned these to the Texas Essential Knowledge and Skills for Earth and Space Science and the Earth Science Literacy Principles. Each team then assembled and sequenced resources according to content strand, balancing the types of learning experiences within each unit. Once units were packaged, teams then considered how they addressed the NGSS and identified the relevant disciplinary core ideas, crosscutting concepts, and science and engineering practices. In addition to providing a brief overview of the project, this

  16. Lightcurve Analysis for Near-Earth Asteroid (143404) 2003 BD44

    Science.gov (United States)

    Polakis, Tom; Warner, Brian D.; Skiff, Brian A.

    2018-01-01

    The synodic rotation period has been determined for the near-Earth asteroid (NEA) (143404) 2003 BD44. The asteroid was observed during three intervals with a rotation period on the order of 79 h determined in each case. The lightcurve exhibited rapidly changing morphology as the asteroid approached. Data have submitted to the ALCDEF database.

  17. Thermal Inertia of near-Earth Asteroids and Strength of the Yarkovsky Effect

    NARCIS (Netherlands)

    Delbo, Marco; Dell'Oro, A.; Harris, A. W.; Mottola, S.; Mueller, M.

    2006-01-01

    Thermal inertia is the physical parameter that controls the temperature distribution over the surface of an asteroid. It affects the strength of the Yarkovsky effect, which causes orbital drift of km-sized asteroids and is invoked to explain the delivery of near-Earth asteroids (NEAs) from the main

  18. Surface Properties of Asteroids from Mid-Infrared Observations and Thermophysical Modeling

    NARCIS (Netherlands)

    Mueller, Michael

    The subject of this work is the physical characterization of asteroids, focusing on the thermal inertia of near-Earth asteroids (NEAs). Thermal inertia governs the Yarkovsky effect, a non-gravitational force which significantly alters the orbits of asteroids up to \\sim 20 km in diameter. Yet, very

  19. Exploring the collisional evolution of the asteroid belt

    Science.gov (United States)

    Bottke, W.; Broz, M.; O'Brien, D.; Campo Bagatin, A.; Morbidelli, A.

    2014-07-01

    The asteroid belt is a remnant of planet-formation processes. By modeling its collisional and dynamical history, and linking the results to constraints, we can probe how the planets and small bodies formed and evolved. Some key model constraints are: (i) The wavy shape of the main-belt size distribution (SFD), with inflection points near 100-km, 10--20-km, 1 to a few km, and ˜0.1-km diameter; (ii) The number of asteroid families created by the catastrophic breakup of large asteroid bodies over the last ˜ 4 Gy, with the number of disrupted D > 100 km bodies as small as ˜20 or as large as 60; (iii) the flux of small asteroids derived from the main belt that have struck the Moon over the last 3.5 Ga --- crater SFDs on lunar terrains with known ages suggest the D 100 km bodies have been significantly battered, but only a fraction have been catastrophically disrupted. Conversely, most small asteroids today are byproducts of fragmentation events. These results are consistent with growing evidence that most of the prominent meteorite classes were produced by young asteroid families. The big question is how to use what we know to determine the main belt's original size and state. This work is ongoing, but dynamical models hint at many possibilities, including both the late arrival and late removal of material from the main belt. In addition, no model has yet properly accounted for the bombardment of the primordial main belt by leftover planetesimals in the terrestrial planet region. It is also possible to use additional constraints, such as the apparent paucity of Vesta-like or V-type objects in the outer main belt, to argue that the primordial main belt at best only 3--4 its current mass at its start. In our talk, we will review what is known, what has been predicted, and some intriguing directions for the future.

  20. Asteroid retrieval missions enabled by invariant manifold dynamics

    Science.gov (United States)

    Sánchez, Joan Pau; García Yárnoz, Daniel

    2016-10-01

    Near Earth Asteroids are attractive targets for new space missions; firstly, because of their scientific importance, but also because of their impact threat and prospective resources. The asteroid retrieval mission concept has thus arisen as a synergistic approach to tackle these three facets of interest in one single mission. This paper reviews the methodology used by the authors (2013) in a previous search for objects that could be transported from accessible heliocentric orbits into the Earth's neighbourhood at affordable costs (or Easily Retrievable Objects, a.k.a. EROs). This methodology consisted of a heuristic pruning and an impulsive manoeuvre trajectory optimisation. Low thrust propulsion on the other hand clearly enables the transportation of much larger objects due to its higher specific impulse. Hence, in this paper, low thrust retrieval transfers are sought using impulsive trajectories as first guesses to solve the optimal control problem. GPOPS-II is used to transcribe the continuous-time optimal control problem to a nonlinear programming problem (NLP). The latter is solved by IPOPT, an open source software package for large-scale NLPs. Finally, a natural continuation procedure that increases the asteroid mass allows to find out the largest objects that could be retrieved from a given asteroid orbit. If this retrievable mass is larger than the actual mass of the asteroid, the asteroid retrieval mission for this particular object is said to be feasible. The paper concludes with an updated list of 17 EROs, as of April 2016, with their maximum retrievable masses by means of low thrust propulsion. This ranges from 2000 tons for the easiest object to be retrieved to 300 tons for the least accessible of them.

  1. Spin states of asteroids in the Eos collisional family

    Science.gov (United States)

    Hanuš, J.; Delbo', M.; Alí-Lagoa, V.; Bolin, B.; Jedicke, R.; Ďurech, J.; Cibulková, H.; Pravec, P.; Kušnirák, P.; Behrend, R.; Marchis, F.; Antonini, P.; Arnold, L.; Audejean, M.; Bachschmidt, M.; Bernasconi, L.; Brunetto, L.; Casulli, S.; Dymock, R.; Esseiva, N.; Esteban, M.; Gerteis, O.; de Groot, H.; Gully, H.; Hamanowa, Hiroko; Hamanowa, Hiromi; Krafft, P.; Lehký, M.; Manzini, F.; Michelet, J.; Morelle, E.; Oey, J.; Pilcher, F.; Reignier, F.; Roy, R.; Salom, P. A.; Warner, B. D.

    2018-01-01

    Eos family was created during a catastrophic impact about 1.3 Gyr ago. Rotation states of individual family members contain information about the history of the whole population. We aim to increase the number of asteroid shape models and rotation states within the Eos collision family, as well as to revise previously published shape models from the literature. Such results can be used to constrain theoretical collisional and evolution models of the family, or to estimate other physical parameters by a thermophysical modeling of the thermal infrared data. We use all available disk-integrated optical data (i.e., classical dense-in-time photometry obtained from public databases and through a large collaboration network as well as sparse-in-time individual measurements from a few sky surveys) as input for the convex inversion method, and derive 3D shape models of asteroids together with their rotation periods and orientations of rotation axes. We present updated shape models for 15 asteroids and new shape model determinations for 16 asteroids. Together with the already published models from the publicly available DAMIT database, we compiled a sample of 56 Eos family members with known shape models that we used in our analysis of physical properties within the family. Rotation states of asteroids smaller than ∼ 20 km are heavily influenced by the YORP effect, whilst the large objects more or less retained their rotation state properties since the family creation. Moreover, we also present a shape model and bulk density of asteroid (423) Diotima, an interloper in the Eos family, based on the disk-resolved data obtained by the Near InfraRed Camera (Nirc2) mounted on the W.M. Keck II telescope.

  2. EVIDENCE FOR GAS FROM A DISINTEGRATING EXTRASOLAR ASTEROID

    International Nuclear Information System (INIS)

    Xu, S.; Jura, M.; Zuckerman, B.; Dufour, P.

    2016-01-01

    We report high-resolution spectroscopic observations of WD 1145+017—a white dwarf that was recently found to be transitted by multiple asteroid-sized objects within its tidal radius. We discovered numerous circumstellar absorption lines with linewidths of ∼300 km s −1 from Mg, Ca, Ti, Cr, Mn, Fe, and Ni, possibly from several gas streams produced by collisions among the actively disintegrating objects. The atmosphere of WD 1145+017 is polluted with 11 heavy elements, including O, Mg, Al, Si, Ca, Ti, V:, Cr, Mn, Fe, and Ni. Evidently, we are witnessing the active disintegration and subsequent accretion of an extrasolar asteroid

  3. Volume and mass distribution in selected families of asteroids

    Science.gov (United States)

    Wlodarczyk, I.; Leliwa-Kopystynski, J.

    2014-07-01

    Members of five asteroid families (Vesta, Eos, Eunomia, Koronis, and Themis) were identified using the Hierarchical Clustering Method (HCM) for a data set containing 292,003 numbered asteroids. The influence of the choice of the best value of the parameter v_{cut} that controls the distances of asteroids in the proper elements space a, e, i was investigated with a step as small as 1 m/s. Results are given in a set of figures showing the families on the planes (a, e), (a, i), (e, i). Another form for the presentation of results is related to the secular resonances in the asteroids' motion with the giant planets, mostly with Saturn. Relations among asteroid radius, albedo, and absolute magnitude allow us to calculate the volumes of individual members of an asteroid family. After summation, the volumes of the parent bodies of the families were found. This paper presents the possibility and the first results of using a combined method for asteroid family identifications based on the following items: (i) Parameter v_{cut} is established with precision as high as 1 m/s; (ii) the albedo (if available) of the potential members is considered for approving or rejecting the family membership; (iii) a color classification is used for the same purpose as well. Searching for the most reliable parameter values for the family populations was performed by means of a consecutive application of the HCM with increasing parameter v_{cut}. The results are illustrated in the figure. Increasing v_{cut} in steps as small as 1 m/s allowed to observe the computational strength of the HCM: the critical value of the parameter v_{cut} (see the breaking-points of the plots in the figure) separates the assemblage of potential family members from 'an ocean' of background asteroids that are not related to the family. The critical values of v_{cut} vary from 57 m/s for the Vesta family to 92 m/s for the Eos family. If the parameter v_{cut} surpasses its critical value, the number of HCM

  4. EVIDENCE FOR GAS FROM A DISINTEGRATING EXTRASOLAR ASTEROID

    Energy Technology Data Exchange (ETDEWEB)

    Xu, S. [European Southern Observatory, Karl-Schwarzschild-Straße 2, D-85748 Garching (Germany); Jura, M.; Zuckerman, B. [Department of Physics and Astronomy, University of California, Los Angeles CA 90095-1562 (United States); Dufour, P., E-mail: sxu@eso.org, E-mail: jura@astro.ucla.edu, E-mail: ben@astro.ucla.edu, E-mail: dufourpa@astro.umontreal.ca [Institut de Recherche sur les Exoplanètes (iREx), Université de Montréal, Montréal, QC H3C 3J7 (Canada)

    2016-01-10

    We report high-resolution spectroscopic observations of WD 1145+017—a white dwarf that was recently found to be transitted by multiple asteroid-sized objects within its tidal radius. We discovered numerous circumstellar absorption lines with linewidths of ∼300 km s{sup −1} from Mg, Ca, Ti, Cr, Mn, Fe, and Ni, possibly from several gas streams produced by collisions among the actively disintegrating objects. The atmosphere of WD 1145+017 is polluted with 11 heavy elements, including O, Mg, Al, Si, Ca, Ti, V:, Cr, Mn, Fe, and Ni. Evidently, we are witnessing the active disintegration and subsequent accretion of an extrasolar asteroid.

  5. Trojan, Hilda, and Cybele asteroids - New lightcurve observations and analysis

    Science.gov (United States)

    Binzel, Richard P.; Sauter, Linda M.

    1992-01-01

    Lightcurve observations of 23 Trojan, Hilda, and Cybele asteroids are presently subjected to a correction procedure for multiple-aspect lightcurves, followed by a quantitative, bias-corrected analysis of lightcurve amplitude distributions for all published data on these asteroids. While the largest Trojans are found to have a higher mean-lightcurve amplitude than their low-albedo, main-belt counterparts, the smaller Trojans and all Hildas and Cybeles display lightcurve properties resembling main-belt objects. Only the largest Trojans have retained their initial forms after subsequent collisional evolution; 90 km may accordingly represent a transitional magnitude between primordial objects and collision fragments.

  6. Guide to the universe asteroids, comets, and dwarf planets

    CERN Document Server

    Rivkin, Andrew

    2009-01-01

    This volume in the Greenwood Guides to the Universe series covers asteroids, comets, and dwarf planets-those small bodies that revolve the Sun-and provides readers with the most up-to-date understanding of the current state of scientific knowledge about them. Scientifically sound, but written with the student in mind, Asteroids, Comets, and Dwarf Planets is an excellent first step for researching the exciting scientific discoveries of the smallest celestial bodies in the solar system.||The book will introduce students to all of the areas of research surrounding the subject, answering many intr

  7. The AKARI IRC asteroid flux catalogue: updated diameters and albedos

    Science.gov (United States)

    Alí-Lagoa, V.; Müller, T. G.; Usui, F.; Hasegawa, S.

    2018-05-01

    The AKARI IRC all-sky survey provided more than twenty thousand thermal infrared observations of over five thousand asteroids. Diameters and albedos were obtained by fitting an empirically calibrated version of the standard thermal model to these data. After the publication of the flux catalogue in October 2016, our aim here is to present the AKARI IRC all-sky survey data and discuss valuable scientific applications in the field of small body physical properties studies. As an example, we update the catalogue of asteroid diameters and albedos based on AKARI using the near-Earth asteroid thermal model (NEATM). We fit the NEATM to derive asteroid diameters and, whenever possible, infrared beaming parameters. We fit groups of observations taken for the same object at different epochs of the survey separately, so we compute more than one diameter for approximately half of the catalogue. We obtained a total of 8097 diameters and albedos for 5170 asteroids, and we fitted the beaming parameter for almost two thousand of them. When it was not possible to fit the beaming parameter, we used a straight line fit to our sample's beaming parameter-versus-phase angle plot to set the default value for each fit individually instead of using a single average value. Our diameters agree with stellar-occultation-based diameters well within the accuracy expected for the model. They also match the previous AKARI-based catalogue at phase angles lower than 50°, but we find a systematic deviation at higher phase angles, at which near-Earth and Mars-crossing asteroids were observed. The AKARI IRC All-sky survey is an essential source of information about asteroids, especially the large ones, since, it provides observations at different observation geometries, rotational coverages and aspect angles. For example, by comparing in more detail a few asteroids for which dimensions were derived from occultations, we discuss how the multiple observations per object may already provide three

  8. In vitro and in vivo antimutagenic effects of DIG, a herbal preparation of Berberis vulgaris, Taraxacum officinale and Arctium lappa, against mitomycin C.

    Science.gov (United States)

    Di Giorgio, C; Boyer, L; De Meo, M; Laurant, C; Elias, R; Ollivier, E

    2015-07-01

    DIG, a liquid herbal preparation made from a mixture of diluted mother tinctures of Berberis vulgaris, Taraxacum officinale and Arctium lappa, was assessed for its antimutagenic properties against mitomycin C. The micronucleus assay on Chinese hamster ovary (CHO)-K1 cells was used to evaluate the in vitro anticlastogenic activity of DIG compared to those of separately diluted mother tinctures. The micronucleus assay was performed on mouse erythrocytes and the comet assay was performed on mouse liver, kidney, lung, brain and testicles to assess the protective effects of DIG (0.2 and 2 % at libitum) against an intraperitoneal injection of mitomycin C (1 mg Kg(-1)) in mice. DIG exerted a powerful anticlastogenic activity, under both pretreatment and simultaneous treatment conditions as assessed by the micronucleus assay in CHO-K1 cells. Its protective activity was greater than that observed for each mother tincture. DIG reduced micronuclei levels in mouse erythrocytes and suppressed >80 % of DNA strand breaks in the liver, kidney, lung, brain and testicles of mice exposed to mitomycin C.

  9. Preliminary design of an asteroid hopping mission

    Science.gov (United States)

    Scheppa, Michael D.

    In 2010, NASA announced that its new vision is to support private space launch operations. It is anticipated that this new direction will create the need for new and innovative ideas that push the current boundaries of space exploration and contain the promise of substantial gain, both in research and capital. The purpose of the study is to plan and estimate the feasibility of a mission to visit a number of near Earth asteroids (NEAs). The mission would take place before the end of the 21st century, and would only use commercially available technology. Throughout the mission design process, while holding astronaut safety paramount, it was the goal to maximize the return while keeping the cost to a minimum. A mission of the nature would appeal to the private space industry because it could be easily adapted and set into motion. The mission design was divided into three main parts; mission timeline, vehicle design and power sources, with emphasis on nuclear and solar electric power, were investigated. The timeline and associated trajectories were initially selected using a numerical estimation and then optimized using Satellite Tool Kit (STK) 9.s's Design Explorer Optimizer [1]. Next, the spacecraft was design using commercially available parts that would support the mission requirements. The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) was and instrumental piece in maximizing the number of NEAs visited. Once the spacecraft was designed, acceptable power supply options were investigated. The VASIMR VX-200 requires 200 kilowatts of power to maintain thrust. This creates the need for a substantial power supply that consists of either a nuclear reactor of massive solar arrays. STK 9.1's Design Explorer Optimizer was able to create a mission time line that allowed for the exploration of seven NEAs in under two years, while keeping the total mission DeltaV under 71 kilometers per second. Based on these initial findings, it is determined that a mission of this

  10. Dig1 protects against cell death provoked by glyphosate-based herbicides in human liver cell lines

    Directory of Open Access Journals (Sweden)

    Travert Carine

    2010-10-01

    Full Text Available Abstract Background Worldwide used pesticides containing different adjuvants like Roundup formulations, which are glyphosate-based herbicides, can provoke some in vivo toxicity and in human cells. These pesticides are commonly found in the environment, surface waters and as food residues of Roundup tolerant genetically modified plants. In order to know their effects on cells from liver, a major detoxification organ, we have studied their mechanism of action and possible protection by precise medicinal plant extracts called Dig1. Methods The cytotoxicity pathways of four formulations of glyphosate-based herbicides were studied using human hepatic cell lines HepG2 and Hep3B, known models to study xenobiotic effects. We monitored mitochondrial succinate dehydrogenase activity and caspases 3/7 for cell mortality and protection by Dig1, as well as cytochromes P450 1A1, 1A2, 3A4 and 2C9 and glutathione-S-transferase to approach the mechanism of actions. Results All the four Roundup formulations provoke liver cell death, with adjuvants having stronger effects than glyphosate alone. Hep3B are 3-5 times more sensitive over 48 h. Caspases 3/7 are greatly activated in HepG2 by Roundup at non-cytotoxic levels, and some apoptosis induction by Roundup is possible together with necrosis. CYP3A4 is specifically enhanced by Roundup at doses 400 times less than used in agriculture (2%. CYP1A2 is increased to a lesser extent together with glutathione-S-transferase (GST down-regulation. Dig 1, non cytotoxic and not inducing caspases by itself, is able to prevent Roundup-induced cell death in a time-dependant manner with an important efficiency of up to 89%, within 48 h. In addition, we evidenced that it prevents Caspases 3/7 activation and CYP3A4 enhancement, and not GST reduction, but in turn it slightly inhibited CYP2C9 when added before Roundup. Conclusion Roundup is able to provoke intracellular disruption in hepatic cell lines at different levels, but a

  11. Implementation of IEC Generic Models of Type 1 Wind Turbine Generator in DIgSILENT PowerFactory

    Institute of Scientific and Technical Information of China (English)

    Haoran ZHAO; Qiuwei WU; Ioannis MARGARIS; Poul S(O)RENSEN

    2013-01-01

    The implementation method for the International Electrotechnical Commission (IEC) generic models of Type 1 wind turbine generator (WTG) in DIgSILENT PowerFactory is presented.The following items are described,i.e.model structure,model blocks and how to implement these blocks in the PowerFactory environment.Case studies under both normal and fault conditions are done with the implemented IEC generic models of Type 1 WTG,and dynamic responses are captured and analyzed.The case study results show that the IEC generic models of Type 1 WTG can correctly represent the performances of Type 1 WTG under both normal and fault conditions.

  12. Feature Extraction for Digging Operation of Excavator Based on Data-Driven Skill-Based PID Controller

    Directory of Open Access Journals (Sweden)

    Kazushige Koiwai

    2017-11-01

    Full Text Available Improvement of the work efficiency is demanded by aging and reducing of the working population in the construction field, so that some automation technologies are applied to construction equipment, such as bulldozers and excavators. However, not only the automation technologies but also expert skills are necessary to improve the work efficiency. In this paper, the human skill evaluation is proposed by the data-driven skill-based PID controller. The proposed method is applied to the excavator digging operation. As the result, the difference between the novice operation and the skilled operation is extracted. Moreover, the numerical difference is clarified based on the result.

  13. NASA's Human Mission to a Near-Earth Asteroid: Landing on a Moving Target

    Science.gov (United States)

    Smith, Jeffrey H.; Lincoln, William P.; Weisbin, Charles R.

    2011-01-01

    This paper describes a Bayesian approach for comparing the productivity and cost-risk tradeoffs of sending versus not sending one or more robotic surveyor missions prior to a human mission to land on an asteroid. The expected value of sample information based on productivity combined with parametric variations in the prior probability an asteroid might be found suitable for landing were used to assess the optimal number of spacecraft and asteroids to survey. The analysis supports the value of surveyor missions to asteroids and indicates one launch with two spacecraft going simultaneously to two independent asteroids appears optimal.

  14. Asteroid Redirect Robotic Mission: Robotic Boulder Capture Option Overview

    Science.gov (United States)

    Mazanek, Daniel D.; Merrill, Raymond G.; Belbin, Scott P.; Reeves, David M.; Earle, Kevin D.; Naasz, Bo J.; Abell, Paul A.

    2014-01-01

    The National Aeronautics and Space Administration (NASA) is currently studying an option for the Asteroid Redirect Robotic Mission (ARRM) that would capture a multi-ton boulder (typically 2-4 meters in size) from the surface of a large (is approximately 100+ meter) Near-Earth Asteroid (NEA) and return it to cislunar space for subsequent human and robotic exploration. This alternative mission approach, designated the Robotic Boulder Capture Option (Option B), has been investigated to determine the mission feasibility and identify potential differences from the initial ARRM concept of capturing an entire small NEA (4-10 meters in size), which has been designated the Small Asteroid Capture Option (Option A). Compared to the initial ARRM concept, Option B allows for centimeter-level characterization over an entire large NEA, the certainty of target NEA composition type, the ability to select the boulder that is captured, numerous opportunities for mission enhancements to support science objectives, additional experience operating at a low-gravity planetary body including extended surface contact, and the ability to demonstrate future planetary defense strategies on a hazardous-size NEA. Option B can leverage precursor missions and existing Agency capabilities to help ensure mission success by targeting wellcharacterized asteroids and can accommodate uncertain programmatic schedules by tailoring the return mass.

  15. Gravity Defied From Potato Asteroids to Magnetised Neutron Stars

    Indian Academy of Sciences (India)

    Gravity Defied. From Potato Asteroids to Magnetised Neutron Stars. 2. ... objects that just missed being stars in this particular install- ment. 1. .... However, the total energy that can be made .... trial metals in which the electrons form a degenerate Fermi gas. ... In deuterium fusion, a deuterium nucleus and a proton combine to.

  16. Asteroid proper elements from an analytical second order theory

    International Nuclear Information System (INIS)

    Knezevic, Z.; Milani, A.

    1989-01-01

    The authors have computed by a fully analytical method a new set of proper elements for 3322 numbered main-belt asteroids. They are presented in the following format: asteroid number, proper semimajor axis (AU), proper eccentricity, sine of proper inclination and quality code (see below). This new set is significantly more accurate than all the previous ones at low to moderate eccentricities and inclinations, and especially near the main mean-motion resonances (e.g., the Themis region). This is because the short periodic perturbations are rigorously removed, and the main effects of the second-order (containing the square of the ratio [the mass of Jupiter/mass of the Sun]) are accounted for. Effects arising from the terms in the Hamiltonian of degree up to four in the eccentricity and inclination of both the asteroid and Jupiter are taken into account, and the fundamental frequencies g (for the perihelion) and s(for the node) of the asteroid are computed with a interative algorithm consistent with the basic results of modern dynamics (e.g., Kolmogorov-Arnold-Moser theory)

  17. The Cool Surfaces of Binaries Near-Earth Asteroids

    NARCIS (Netherlands)

    Delbo, Marco; Walsh, K.; Mueller, M.

    2008-01-01

    We present results from thermal-infrared observations of binary near-Earth asteroids (NEAs). These objects, in general, have surface temperatures cooler than the average values for non-binary NEAs. We discuss how this may be evidence of higher-than-average surface thermal inertia. The comparison of

  18. FIRST VLTI-MIDI DIRECT DETERMINATIONS OF ASTEROID SIZES

    International Nuclear Information System (INIS)

    Delbo, M.; Ligori, S.; Cellino, A.; Matter, A.; Berthier, J.

    2009-01-01

    We have obtained the first successful interferometric measurements of asteroid sizes and shapes by means of the Very Large Telescope Interferometer-Mid-Infrared Interferometric Instrument (VLTI-MIDI). The VLTI can spatially resolve asteroids in a range of sizes and heliocentric distances that are not accessible to other techniques such as adaptive optics and radar. We have observed, as a typical bench mark, the asteroid (951) Gaspra, visited in the past by the Galileo space probe, and we derive a size in good agreement with the ground truth coming from the in situ measurements by the Galileo mission. Moreover, we have also observed the asteroid (234) Barbara, known to exhibit unusual polarimetric properties, and we found evidence of a potential binary nature. In particular, our data are best fit by a system of two bodies of 37 and 21 km in diameter, separated by a center-to-center distance of ∼24 km (projected along the direction of the baseline at the epoch of our observations).

  19. Photometry and models of eight near-Earth asteroids

    Czech Academy of Sciences Publication Activity Database

    Kaasalainen, M.; Pravec, Petr; Krugly, Yu. N.; Kotková, Lenka; Torppa, J.; Virtanen, J.; Kaasalainen, S.; Erikson, A.; Nathues, A.; Ďurech, J.; Wolf, M.; Lagerros, J. S. V.; Lindgren, M.; Lagerkvist, C.-I.; Koff, R.; Davies, J.; Mann, R.; Kušnirák, Peter; Gaftonyuk, N. M.; Shevchenko, V. G.; Chiorny, V. G.; Belskaya, I. N.

    2004-01-01

    Roč. 167, č. 1 (2004), s. 178-196 ISSN 0019-1035 R&D Projects: GA AV ČR IAA3003204; GA ČR GA205/99/0255 Institutional research plan: CEZ:AV0Z1003909 Keywords : asteroids * rotation * photometry Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.074, year: 2004

  20. Disaggregation of small, cohesive rubble pile asteroids due to YORP

    Science.gov (United States)

    Scheeres, D. J.

    2018-04-01

    The implication of small amounts of cohesion within relatively small rubble pile asteroids is investigated with regard to their evolution under the persistent presence of the YORP effect. We find that below a characteristic size, which is a function of cohesive strength, density and other properties, rubble pile asteroids can enter a "disaggregation phase" in which they are subject to repeated fissions after which the formation of a stabilizing binary system is not possible. Once this threshold is passed rubble pile asteroids may be disaggregated into their constituent components within a finite time span. These constituent components will have their own spin limits - albeit potentially at a much higher spin rate due to the greater strength of a monolithic body. The implications of this prediction are discussed and include modification of size distributions, prevalence of monolithic bodies among meteoroids and the lifetime of small rubble pile bodies in the solar system. The theory is then used to place constraints on the strength of binary asteroids characterized as a function of their type.

  1. Post mitigation impact risk analysis for asteroid deflection demonstration missions

    Science.gov (United States)

    Eggl, Siegfried; Hestroffer, Daniel; Thuillot, William; Bancelin, David; Cano, Juan L.; Cichocki, Filippo

    2015-08-01

    Even though mankind believes to have the capabilities to avert potentially disastrous asteroid impacts, only the realization of mitigation demonstration missions can validate this claim. Such a deflection demonstration attempt has to be cost effective, easy to validate, and safe in the sense that harmless asteroids must not be turned into potentially hazardous objects. Uncertainties in an asteroid's orbital and physical parameters as well as those additionally introduced during a mitigation attempt necessitate an in depth analysis of deflection mission designs in order to dispel planetary safety concerns. We present a post mitigation impact risk analysis of a list of potential kinetic impactor based deflection demonstration missions proposed in the framework of the NEOShield project. Our results confirm that mitigation induced uncertainties have a significant influence on the deflection outcome. Those cannot be neglected in post deflection impact risk studies. We show, furthermore, that deflection missions have to be assessed on an individual basis in order to ensure that asteroids are not inadvertently transported closer to the Earth at a later date. Finally, we present viable targets and mission designs for a kinetic impactor test to be launched between the years 2025 and 2032.

  2. A Martian origin for the Mars Trojan asteroids

    Science.gov (United States)

    Polishook, D.; Jacobson, S. A.; Morbidelli, A.; Aharonson, O.

    2017-08-01

    Seven of the nine known Mars Trojan asteroids belong to an orbital cluster1,2 named after its largest member, (5261) Eureka. Eureka is probably the progenitor of the whole cluster, which formed at least 1 Gyr ago3. It has been suggested3 that the thermal YORP (Yarkovsky-O'Keefe-Radzievskii-Paddack) effect spun up Eureka, resulting in fragments being ejected by the rotational-fission mechanism. Eureka's spectrum exhibits a broad and deep absorption band around 1 μm, indicating an olivine-rich composition4. Here we show evidence that the Trojan Eureka cluster progenitor could have originated as impact debris excavated from the Martian mantle. We present new near-infrared observations of two Trojans ((311999) 2007 NS2 and (385250) 2001 DH47) and find that both exhibit an olivine-rich reflectance spectrum similar to Eureka's. These measurements confirm that the progenitor of the cluster has an achondritic composition4. Olivine-rich reflectance spectra are rare amongst asteroids5 but are seen around the largest basins on Mars6. They are also consistent with some Martian meteorites (for example, Chassigny7) and with the material comprising much of the Martian mantle8,9. Using numerical simulations, we show that the Mars Trojans are more likely to be impact ejecta from Mars than captured olivine-rich asteroids transported from the main belt. This result directly links specific asteroids to debris from the forming planets.

  3. 78 FR 64253 - NASA Asteroid Initiative Idea Synthesis Workshop

    Science.gov (United States)

    2013-10-28

    ... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION [Notice: 13-124] NASA Asteroid Initiative Idea.... SUMMARY: The National Aeronautics and Space Administration announces that the agency will resume the NASA... INFORMATION CONTACT: Michele Gates, Senior Technical Advisor, NASA Human Exploration and Operations Mission...

  4. Multi-wavelength observations of Asteroid 2100 Ra-Shalom

    Czech Academy of Sciences Publication Activity Database

    Shepard, M.K.; Clark, B. E.; Nolan, M. C.; Benner, L. A. M.; Ostro, S. J.; Giorgini, J. D.; Vilas, F.; Jarvis, K.; Lederer, S.; Lim, L.F.; McConnochie, T.; Bell, J.; Margot, J. L.; Rivkin, A. S.; Magrik, C.; Scheeres, D.J.; Pravec, Petr

    2008-01-01

    Roč. 193, č. 1 (2008), s. 20-38 ISSN 0019-1035 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroids composition * radar observations Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.268, year: 2008

  5. Physical modeling of near-Earth Asteroid (29075) 1950 DA

    Czech Academy of Sciences Publication Activity Database

    Busch, M.W.; Giorgini, J. D.; Ostro, S. J.; Benner, L. A. M.; Jurgens, R. F.; Rose, R.; Hicks, M. D.; Pravec, Petr; Kušnirák, Peter; Ireland, M.J.; Scheeres, D.J.; Broschart, S.B.; Magri, C.; Nolan, M. C.; Hine, A. A.; Margot, J. L.

    2007-01-01

    Roč. 190, č. 2 (2007), s. 608-621 ISSN 0019-1035 Grant - others:GA ČR(CZ) GA208/99/0255 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroids * composition * dynamics * rotation Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.869, year: 2007

  6. Thermal infrared observations of asteroid (99942) Apophis with Herschel

    Czech Academy of Sciences Publication Activity Database

    Müller, T. G.; Kiss, C.; Scheirich, Peter; Pravec, Petr; O'Rourke, L.; Vilenius, E.; Altieri, B.

    2014-01-01

    Roč. 566, June (2014), A22/1-A22/10 ISSN 0004-6361 R&D Projects: GA ČR GAP209/12/0229; GA MŠk LG12001 Institutional support: RVO:67985815 Keywords : minor planets * asteroids: individual * radiation mechanisms Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.378, year: 2014

  7. Photometric observations of Earth-impacting asteroid 2008 TC(3)

    Czech Academy of Sciences Publication Activity Database

    Kozubal, M.; Gasdia, F.W.; Dantowitz, R.; Scheirich, Peter; Harris, A. W.

    2011-01-01

    Roč. 46, č. 4 (2011), s. 534-542 ISSN 1086-9379 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroid * photometric observations Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.719, year: 2011

  8. New findings on asteroid spin-vector distributions

    Czech Academy of Sciences Publication Activity Database

    Kryszczynska, A.; La Spina, A.; Paolicchi, P.; Harris, A. W.; Breiter, S.; Pravec, Petr

    2007-01-01

    Roč. 192, č. 1 (2007), s. 223-237 ISSN 0019-1035 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroids * rotation Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.869, year: 2007

  9. The trajectory, structure and origin of the Chelyabinsk asteroidal impactor

    Science.gov (United States)

    Borovička, Jiří; Spurný, Pavel; Brown, Peter; Wiegert, Paul; Kalenda, Pavel; Clark, David; Shrbený, Lukáš

    2013-11-01

    Earth is continuously colliding with fragments of asteroids and comets of various sizes. The largest encounter in historical times occurred over the Tunguska river in Siberia in 1908, producing an airburst of energy equivalent to 5-15 megatons of trinitrotoluene (1 kiloton of trinitrotoluene represents an energy of 4.185 × 1012 joules). Until recently, the next most energetic airburst events occurred over Indonesia in 2009 and near the Marshall Islands in 1994, both with energies of several tens of kilotons. Here we report an analysis of selected video records of the Chelyabinsk superbolide of 15 February 2013, with energy equivalent to 500 kilotons of trinitrotoluene, and details of its atmospheric passage. We found that its orbit was similar to the orbit of the two-kilometre-diameter asteroid 86039 (1999 NC43), to a degree of statistical significance sufficient to suggest that the two were once part of the same object. The bulk strength--the ability to resist breakage--of the Chelyabinsk asteroid, of about one megapascal, was similar to that of smaller meteoroids and corresponds to a heavily fractured single stone. The asteroid broke into small pieces between the altitudes of 45 and 30 kilometres, preventing more-serious damage on the ground. The total mass of surviving fragments larger than 100 grams was lower than expected.

  10. Binary asteroid population. 3. Secondary rotations and elongations

    Czech Academy of Sciences Publication Activity Database

    Pravec, Petr; Scheirich, Peter; Kušnirák, Peter; Hornoch, Kamil; Galád, Adrián; Naidu, S.P.; Pray, D. P.; Világi, J.; Gajdoš, Š.; Kornoš, L.

    2016-01-01

    Roč. 267, March (2016), s. 267-295 ISSN 0019-1035 R&D Projects: GA ČR GAP209/12/0229; GA ČR GA15-07193S Institutional support: RVO:67985815 Keywords : asteroids * rotation * dynamics Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.131, year: 2016

  11. Linking main-belt comets to asteroid families

    Science.gov (United States)

    Novakovic, B.; Hsieh, H. H.; Cellino, A.

    2012-09-01

    Here we present our results obtained by applying different methods in order to establish a firm link between the main-belt comets (MBCs) and colisionally-formed asteroid families (AFs), i.e, to possibly find additional line of evidence supporting the hypothesis that MBCs may be preferentially found among the members of young AFs.

  12. Very low strengths of interplanetary meteoroids and small asteroids

    Czech Academy of Sciences Publication Activity Database

    Popova, O. P.; Borovička, Jiří; Hartman, W.K.; Spurný, Pavel; Gnos, E.; Nemtchinov, I. V.; Trigo-Rodríguez, J.M.

    2011-01-01

    Roč. 46, č. 10 (2011), s. 1525-1550 ISSN 1086-9379 Institutional research plan: CEZ:AV0Z10030501 Keywords : meteoroids * small asteroids * photographic observations Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.719, year: 2011

  13. B612 plans asteroid hunt with fleet of small satellites

    Science.gov (United States)

    Mann, Adam

    2018-05-01

    Last week, an asteroid the size of Egypt's Great Pyramid of Giza whizzed by Earth, missing it by half the distance to the moon. The concern that we may one day not be so lucky has long preoccupied the B612 Foundation, a private organization in Mill Valley, California, dedicated to finding asteroids that cross Earth's orbit and could devastate humanity. B612 itself had a near-death experience 3 years ago, when its bold plans for an asteroid-hunting space telescope fell apart. But now, its ambitions are rising again with a new technique for finding menacing objects. On 10 May, B612 announced a partnership with York Space Systems to investigate building a fleet of small asteroid hunters. For many years, B612 aimed to build and launch a much larger craft, Sentinel, a $450 million space telescope with a 50-centimeter mirror. But fundraising stalled and, in 2015, NASA ended an agreement to help B612 because it wasn't meeting mileposts, essentially killing the telescope. Now, B612 has developed a new technique, called synthetic tracking, that can produce similar results at a far lower cost with small space telescopes. Ed Lu, B612 co-founder and CEO, expects the first telescope to cost about $10 million and believes a full constellation "would be a factor of many, many cheaper" than Sentinel.

  14. Radar Observations of Main-Belt M-class Asteroids

    NARCIS (Netherlands)

    Shepard, Michael K.; Clark, B. E.; Ockert-Bell, M.; Nolan, M. C.; Howell, E. S.; Magri, C.; Giorgini, J. D.; Benner, L. A. M.; Ostro, S. J.; Harris, A. W.; Warner, B. D.; Stephens, R. D.; Mueller, M.

    2009-01-01

    Using the S-band radar at Arecibo Observatory, we have observed 19 Tholen M-class asteroids. The mean radar albedo for all our targets is 0.28 ± 0.13, considerably higher than the mean radar albedo of every other class (Magri et al. 2007, Icarus 186, 126-151). We find approximately one-third (six)

  15. Lightcurve Analysis for Four Near-Earth Asteroids

    Science.gov (United States)

    Birtwhistle, Peter

    2018-04-01

    Lightcurves are reported for four near-Earth asteroids observed from Great Shefford Observatory during close approaches between 2010 January and 2017 November: 2000 RE52, 2008 YZ32, 2017 UK8, and 2017 VD. 2008 YZ32 is a large superfast rotator.

  16. Assessment of the Gaussian Covariance Approximation over an Earth-Asteroid Encounter Period

    Science.gov (United States)

    Mattern, Daniel W.

    2017-01-01

    In assessing the risk an asteroid may pose to the Earth, the asteroids state is often predicted for many years, often decades. Only by accounting for the asteroids initial state uncertainty can a measure of the risk be calculated. With the asteroids state uncertainty growing as a function of the initial velocity uncertainty, orbit velocity at the last state update, and the time from the last update to the epoch of interest, the asteroids position uncertainties can grow to many times the size of the Earth when propagated to the encounter risk corridor. This paper examines the merits of propagating the asteroids state covariance as an analytical matrix. The results of this study help to bound the efficacy of applying different metrics for assessing the risk an asteroid poses to the Earth. Additionally, this work identifies a criterion for when different covariance propagation methods are needed to continue predictions after an Earth-encounter period.

  17. Regrowth of Cirsium arvense from intact roots and root fragments at different soil depths

    Directory of Open Access Journals (Sweden)

    Thomsen, Mette Goul

    2014-02-01

    Full Text Available In the present work we measured the shoot rate from intact roots and from root fragments of Cirsium arvense at different digging depths and the number of leaves were used as estimate of minimum regenerative capacity. The experiments were performed on four sites with three or four repetitions of each treatment. On each site plot, the soil was removed down to a given depth within a 1 x 1 m square. All plant parts was excavated from the soil and the soil was either replaced without any root material, or roots of C. arvense was cut into 10 cm long fragments and replaced into the source hole. Shoot number, aboveground biomass and number of leaves were measured. Digging depth and time explained 50% - 60% of the variation in biomass (P<0.001. Replacement of root fragments increased the shoot number in one out of four treatments but did not affect biomass produced compared to production from undisturbed root systems. Number of leaves showed that shoots from all digging depths passed the level of minimum regenerative capacity. We conclude that the intact root system from all depths was able to regenerate within one season and it has a high contribution to the produced biomass compared with root fragments in the upper soil layers.

  18. NASA's Asteroid Redirect Mission: The Boulder Capture Option

    Science.gov (United States)

    Abell, Paul A.; Nuth, J.; Mazanek, D.; Merrill, R.; Reeves, D.; Naasz, B.

    2014-01-01

    NASA is examining two options for the Asteroid Redirect Mission (ARM), which will return asteroid material to a Lunar Distant Retrograde Orbit (LDRO) using a robotic solar-electric-propulsion spacecraft, called the Asteroid Redirect Vehicle (ARV). Once the ARV places the asteroid material into the LDRO, a piloted mission will rendezvous and dock with the ARV. After docking, astronauts will conduct two extravehicular activities (EVAs) to inspect and sample the asteroid material before returning to Earth. One option involves capturing an entire small (approximately 4-10 m diameter) near-Earth asteroid (NEA) inside a large inflatable bag. However, NASA is examining another option that entails retrieving a boulder (approximately 1-5 m) via robotic manipulators from the surface of a larger (approximately 100+ m) pre-characterized NEA. This option can leverage robotic mission data to help ensure success by targeting previously (or soon to be) well-characterized NEAs. For example, the data from the Hayabusa mission has been utilized to develop detailed mission designs that assess options and risks associated with proximity and surface operations. Hayabusa's target NEA, Itokawa, has been identified as a valid target and is known to possess hundreds of appropriately sized boulders on its surface. Further robotic characterization of additional NEAs (e.g., Bennu and 1999 JU3) by NASA's OSIRIS REx and JAXA's Hayabusa 2 missions is planned to begin in 2018. The boulder option is an extremely large sample-return mission with the prospect of bringing back many tons of well-characterized asteroid material to the Earth-Moon system. The candidate boulder from the target NEA can be selected based on inputs from the world-wide science community, ensuring that the most scientifically interesting boulder be returned for subsequent sampling. This boulder option for NASA's ARM can leverage knowledge of previously characterized NEAs from prior robotic missions, which provides more

  19. Moving an asteroid with electric solar wind sail

    Science.gov (United States)

    Merikallio, S.; Janhunen, P.

    2010-12-01

    The electric solar wind sail (E-Sail) is a new propulsion method for interplanetary travel which was invented in 2006 and is currently under development. The E-Sail uses charged tethers to extract momentum from the solar wind particles to obtain propulsive thrust. According to current estimates, the E-Sail is 2-3 orders of magnitude better than traditional propulsion methods (chemical rockets and ion engines) in terms of produced lifetime-integrated impulse per propulsion system mass. Here we analyze the problem of using the E-Sail for directly deflecting an Earth-threatening asteroid. The problem then culminates into how to attach the E-Sail device to the asteroid. We assess alternative attachment strategies, namely straightforward direct towing with a cable and the gravity tractor method which works for a wider variety of situations. We also consider possible techniques to scale up the E-Sail force beyond the baseline one Newton level to deal with more imminent or larger asteroid or cometary threats. As a baseline case we consider an asteroid of effective diameter of 140 m and mass of 3 million tons, which can be deflected with a baseline 1 N E-Sail within 10 years. With a 5 N E-Sail the deflection could be achieved in 5 years. Once developed, the E-Sail would appear to provide a safe and reasonably low-cost way of deflecting dangerous asteroids and other heavenly bodies in cases where the collision threat becomes known several years in advance.

  20. Observations of Near-Earth Asteroids in Polarized Light

    Science.gov (United States)

    Afanasiev, V. L.; Ipatov, A. V.

    2018-04-01

    We report the results of position, photometric, and polarimetric observations of two near-Earth asteroids made with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. 1.2-hour measurements of the photometric variations of the asteroid 2009 DL46 made onMarch 8, 2016 (approximately 20m at a distance of about 0.23 AU from the Earth) showed a 0.m2-amplitude flash with a duration of about 20 minutes. During this time the polarization degree increased from the average level of 2-3% to 14%. The angle of the polarization plane and the phase angle were equal to 113° ± 1° and 43°, respectively. Our result indicates that the surface of the rotating asteroid (the rotation period of about 2.5 hours) must be non-uniformly rough. Observations of another asteroid—1994 UG—whose brightness was of about 17m and which was located at a geocentric distance of 0.077 AU, were carried out during the night of March 6/7, 2016 in two modes: photometric and spectropolarimetric. According to the results of photometric observations in Johnson's B-, V-, and R-band filters, over one hour the brightness of the asteroid remained unchanged within the measurement errors (about 0.m02). Spectropolarimetric observations in the 420-800 nm wavelength interval showed the polarization degree to decrease from 8% in the blue part of the spectrum to 2% in the red part with the phase angle equal to 44°, which is typical for S-type near-Earth asteroids.