398 research outputs found
CubeSat Initiatives at KSC
Even though the Small PayLoad Integrated Testing Services or SPLITS line of business is newly established, KSC has been involved in a variety of CubeSat projects and programs. CubeSat development projects have been initiated through educational outreach partnerships with schools and universities, commercial partnerships and internal training initiatives. KSC has also been involved in CubeSat deployment through programs to find launch opportunities to fly CubeSats as auxiliary payloads on previously planned missions and involvement in the development of new launch capabilities for small satellites. This overview will highlight the CubeSat accomplishments at KSC and discuss planning for future projects and opportunities
Launch Environment Water Flow Simulations Using Smoothed Particle Hydrodynamics
This paper describes the use of Smoothed Particle Hydrodynamics (SPH) to simulate the water flow from the rainbird nozzle system used in the sound suppression system during pad abort and nominal launch. The simulations help determine if water from rainbird nozzles will impinge on the rocket nozzles and other sensitive ground support elements
Comparing Maps of Mean Monthly Surface Temperature and Precipitation for Alaska and Adjacent Areas of Canada Produced by Two Different Methods
Maps of mean monthly surface temperature and precipitation for Alaska and adjacent areas of Canada, produced by Oregon State Universityâs Spatial Climate Analysis Service (SCAS) and the Alaska Geospatial Data Clearinghouse (AGDC), were analyzed. Because both sets of maps are generally available and in use by the community, there is a need to document differences between the processes and input data sets used by the two groups to produce their respective set of maps and to identify similarities and differences between the two sets of maps and possible reasons for the differences. These differences do not affect the observed large-scale patterns of seasonal and annual variability. Alaska is divided into interior and coastal zones, with consistent but different variability, separated by a transition region. The transition region has high interannual variability but low long-term mean variability. Both data sets support the four major ecosystems and ecosystem transition zone identified in our earlier work. Differences between the two sets of maps do occur, however, on the regional scale; they reflect differences in physiographic domains and in the treatment of these domains by the two groups (AGDC, SCAS). These differences also provide guidance for an improved observational network for Alaska. On the basis of validation with independent in situ data, we conclude that the data set produced by SCAS provides the best spatial coverage of Alaskan long-term mean monthly surface temperature and precipitation currently available.On a analysĂ© des cartes reprĂ©sentant les moyennes mensuelles des prĂ©cipitations et des tempĂ©ratures de lâair en surface pour lâAlaska et les zones contiguĂ«s du Canada. Ces cartes avaient Ă©tĂ© Ă©tablies par le service dâanalyse du climat spatial (SCAS) de lâuniversitĂ© de lâOregon et le centre dâĂ©change de donnĂ©es gĂ©ospatiales de lâAlaska (AGDC). Vu quâen gĂ©nĂ©ral le public peut se procurer les deux ensembles de cartes et quâil les utilise, il est nĂ©cessaire de documenter les diffĂ©rences entre les processus et les jeux de donnĂ©es dâentrĂ©e utilisĂ©s par les deux groupes pour crĂ©er leur propre ensemble de cartes, ainsi que de dĂ©gager les similaritĂ©s et les diffĂ©rences entre les deux ensembles de cartes et les raisons possibles de ces diffĂ©rences. Ces derniĂšres nâaffectent pas les schĂ©mas de variabilitĂ© saisonniĂšre et annuelle observĂ©s Ă grande Ă©chelle. LâAlaska est divisĂ© en zones intĂ©rieures et zones cĂŽtiĂšres, possĂ©dant une variabilitĂ© constante mais diffĂ©rente, sĂ©parĂ©es par une rĂ©gion de transition. Celle-ci possĂšde une grande variabilitĂ© interannuelle mais une faible variabilitĂ© Ă long terme de la moyenne. Les deux jeux de donnĂ©es sont compatibles avec les quatre grands Ă©cosystĂšmes et leurs zones de transition que nous avions identifiĂ©s dans nos travaux antĂ©rieurs. Il y a cependant des diffĂ©rences Ă lâĂ©chelle rĂ©gionale entre les deux ensembles de cartes; elles tĂ©moignent de diffĂ©rences dans les domaines physiographiques et dans le traitement que font les deux groupes (AGDC et SCAS) de ces domaines. Ces diffĂ©rences offrent Ă©galement une piste pour lâĂ©tablissement dâun rĂ©seau dâobservation amĂ©liorĂ© pour lâAlaska. En nous basant sur une validation fondĂ©e sur des donnĂ©es indĂ©pendantes recueillies in situ, nous concluons que le jeu de donnĂ©es produit par SCAS reprĂ©sente actuellement la meilleure couverture spatiale disponible pour les moyennes mensuelles Ă long terme des prĂ©cipitations et des tempĂ©ratures de lâair en surface en Alaska
Novel ultrastructures of Treponema primitia and their implications for motility
Members of the bacterial phylum Spirochaetes are generally helical cells propelled by periplasmic flagella. The spirochete Treponema primitia is interesting because of its mutualistic role in the termite gut, where it is believed to cooperate with protozoa that break down cellulose and produce H2 as a by-product. Here we report the ultrastructure of T. primitia as obtained by electron cryotomography of intact, frozen-hydrated cells. Several previously unrecognized external structures were revealed, including bowl-like objects decorating the outer membrane, arcades of hook-shaped proteins winding along the exterior and tufts of fibrils extending from the cell tips. Inside the periplasm, cone-like structures were found at each pole. Instead of the single peptidoglycan layer typical of other Gram-negative bacteria, two distinct periplasmic layers were observed. These layers formed a central open space that contained two flagella situated adjacent to each other. In some areas, the inner membrane formed flattened invaginations that protruded into the cytoplasm. High-speed light microscopic images of swimming T. primitia cells showed that cell bodies remained rigid and moved in a helical rather than planar motion. Together, these findings support the 'rolling cylinder' model for T. primitia motility that posits rotation of the protoplasmic cylinder within the outer sheath
Bose-Einstein condensates in standing waves: The cubic nonlinear Schroedinger equation with a periodic potential
We present a new family of stationary solutions to the cubic nonlinear
Schroedinger equation with a Jacobian elliptic function potential. In the limit
of a sinusoidal potential our solutions model a dilute gas Bose-Einstein
condensate trapped in a standing light wave. Provided the ratio of the height
of the variations of the condensate to its DC offset is small enough, both
trivial phase and nontrivial phase solutions are shown to be stable. Numerical
simulations suggest such stationary states are experimentally observable.Comment: 4 pages, 4 figure
Testing and Modeling of the Mars Atmospheric Processing Module
Here we report further progress in the development of the MARCO POLO-Mars Pathfinder Atmospheric Processing Module (APM). The APM is designed to demonstrate in situ resource utilization (ISRU) of the Martian atmosphere, which primarily consists of carbon dioxide (CO2). The APM is part of a larger project with the overall goal of collecting and utilizing CO2 found in the atmosphere and water in the regolith of Mars to produce methane and oxygen to be used as rocket propellant, eliminating the need to import those to Mars for human missions, thus significantly reducing costs. The initial focus of NASA's new ISRU Project is modeling of key ISRU components, such as the CO2 Freezers and the Sabatier reactor of the APM. We have designed models of those components and verified the models with the APM by gathering additional data for the Sabatier reactor. Future efforts will be focused on simultaneous operations of the APM and other MARCO POLO-Mars Pathfinder modules
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The shared socio-economic pathway (SSP) greenhouse gas concentrations and their extensions to 2500
Anthropogenic increases in atmospheric greenhouse gas concentrations are the main driver of current and future climate change. The integrated assessment community has quantified anthropogenic emissions for the shared socio-economic pathway (SSP) scenarios, each of which represents a different future socio-economic projection and political environment. Here, we provide the greenhouse gas concentrations for these SSP scenarios â using the reduced-complexity climateâcarbon-cycle model MAGICC7.0. We extend historical, observationally based concentration data with SSP concentration projections from 2015 to 2500 for 43 greenhouse gases with monthly and latitudinal resolution. CO2 concentrations by 2100 range from 393 to 1135âppm for the lowest (SSP1-1.9) and highest (SSP5-8.5) emission scenarios, respectively. We also provide the concentration extensions beyond 2100 based on assumptions regarding the trajectories of fossil fuels and land use change emissions, net negative emissions, and the fraction of non-CO2 emissions. By 2150, CO2 concentrations in the lowest emission scenario are approximately 350âppm and approximately plateau at that level until 2500, whereas the highest fossil-fuel-driven scenario projects CO2 concentrations of 1737âppm and reaches concentrations beyond 2000âppm by 2250. We estimate that the share of CO2 in the total radiative forcing contribution of all considered 43 long-lived greenhouse gases increases from 66â% for the present day to roughly 68â% to 85â% by the time of maximum forcing in the 21st century. For this estimation, we updated simple radiative forcing parameterizations that reflect the Oslo Line-By-Line model results. In comparison to the representative concentration pathways (RCPs), the five main SSPs (SSP1-1.9, SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) are more evenly spaced and extend to lower 2100 radiative forcing and temperatures. Performing two pairs of six-member historical ensembles with CESM1.2.2, we estimate the effect on surface air temperatures of applying latitudinally and seasonally resolved GHG concentrations. We find that the ensemble differences in the MarchâAprilâMay (MAM) season provide a regional warming in higher northern latitudes of up to 0.4âK over the historical period, latitudinally averaged of about 0.1âK, which we estimate to be comparable to the upper bound (âŒ5â% level) of natural variability. In comparison to the comparatively straight line of the last 2000 years, the greenhouse gas concentrations since the onset of the industrial period and this studies' projections over the next 100 to 500 years unequivocally depict a âhockey-stickâ upwards shape. The SSP concentration time series derived in this study provide a harmonized set of input assumptions for long-term climate science analysis; they also provide an indication of the wide set of futures that societal developments and policy implementations can lead to â ranging from multiple degrees of future warming on the one side to approximately 1.5ââC warming on the other
Standalone vertex ïŹnding in the ATLAS muon spectrometer
A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at âs = 7 TeV collected with the ATLAS detector at the LHC during 2011
Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC
Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H âÎł Îł, H â Z Zâ â4l and H âW Wâ âlÎœlÎœ. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of âs = 7 TeV and âs = 8 TeV, corresponding to an integrated luminosity of about 25 fbâ1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined ïŹts probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson
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