silkski/ENERAD huggingface dataset:
Following the success of the VLBI Space Observatory Program ( VSOP ) , a next generation space VLBI mission , VSOP-2 , is currently being planned . Higher observing frequencies , cooled receivers , increased bandwidths and larger telescope diameters will result in gains in resolution and interferometer sensitivity by factors of 10 over the VSOP mission . The use of phase - referencing by fast switching between a calibrator source and the target source is now being studied as this technique allows sources 50 - 150 times weaker to be observed depending on the frequency band . Such a capability would greatly enhance the VSOP-2 mission . Several other enhancements to the VSOP-2 mission are also presently under investigation including the VSOP-2 spacecraft operating at the same time as a US spacecraft to form what has come to be known as the iARISE ( international ARISE ) mission .
A mission - systems architecture based on a highly modular " systems of systems " infrastructure utilizing open - standards hardware and software interfaces as the enabling technology is absolutely essential for an affordable and sustainable space exploration program . This architecture requires ( a ) robust communication between heterogeneous systems , ( b ) high reliability , ( c ) minimal mission - to - mission reconfiguration , ( d ) affordable development , system integration , and verification of systems , and ( e ) minimum sustaining engineering . This paper proposes such an architecture . Lessons learned from the space shuttle program are applied to help define and refine the model .
My task this morning is to review the history and current direction of fuel cell technology development for NASA 's human spaceflight program and to compare it to the directions being taken in that field for The Hydrogen Economy . The concept of " The Hydrogen Economy " involves many applications for fuel cells , but for today 's discussion , I 'll focus on automobiles .
Within this paper , control - relevant vehicle design concepts are examined using a widely used 3 DOF ( plus flexibility ) nonlinear model for the longitudinal dynamics of a generic carrot - shaped scramjet powered hypersonic vehicle . The impact of elevator size and placement on control - relevant static properties ( e.g. level - flight trimmable region , trim controls , Angle of Attack ( AOA ) , thrust margin ) and dynamic properties ( e.g. instability and right half plane zero associated with flight path angle ) are examined . Elevator usage has been examine for a class of typical hypersonic trajectories .
This paper discusses a study of two alternate oxidizers , liquid oxygen and hydrogen peroxide , for use in a rocket based combined cycle ( RBCC ) demonstrator vehicle . The flight vehicle is baselined as an airlaunched self - powered Mach 0.7 to 7 demonstration of an RBCC engine through all or its air breathing propulsion modes . Selection of an alternate oxidizer has the potential to lower overall vehicle size , system complexity/ cost and ultimately the total program risk . This trade study examined the oxidizer selection effects upon the overall vehicle performance , safety and operations . After consideration of all the technical and programmatic details available at this time , 90 % hydrogen peroxide was selected over liquid oxygen for use in this program .
In this presentation we will explore several distributed consensus algorithms developed to maintain coordination among a fleet of heterogeneous UAS subject to external disturbances . An overview of the network assumptions and autopilot performance bounds required to meet the coordination objective will be provided . In particular , we will leverage passivity - based stability conditions for bidirectional networks that require the communication graph to be connected in an integral sense , but may fail to connect pointwise in time during the entire mission . Non - ideal autopilots that can only track a desired speed profile with a prescribed precision induce an error in vehicle coordination . The autopilot performance bounds will be propagated through the coordination dynamics to understand the limits introduced by autopilots .
The object of this study was to investigate the micro - structural response of DP 600 subjected to high strain rate , ballistic impact tests . The ballistic tests were conducted using normal impact of a hardened steel penetrator into a 2 mm thick sheet of DP 600 . The average strain rates produced from this test method are on the order of 10(exp 5)/s . Electron microscopy was used to investigate the microstructure before and after high strain rate deformation . A variation in material response was observed between tests conducted at 0.8 x 105 and 25 x 10(exp 5)/s .
The effects of mechanical stirring on nucleation and chiral symmetry breaking have been investigated for a simple inorganic molecule , sodium chlorate ( NaClO3 ) . In contrast to earlier findings , our experiment suggests that the symmetry breaking may have little to do with hydrodynamic convection . Rather the effect can be reasonably accounted for by mechanical damage to incipient crystals . The catastrophic events , creating numerous small ' secondary ' crystals , produce statistical domination of one chiral species over the other . Our conclusion is supported by a number of observations using different mixing mechanisms .
The use of CFD to directly predict helicopter main rotor noise is shown to be quite promising as an alternative mean for low frequency source noise evaluation . Results using existing state - of - the - art grid structures and finite - difference schemes demonstrated that small perturbation pressures , associated with acoustics radiation , can be extracted with some degree of fidelity . Accuracy of the predictions are demonstrated via comparing to predictions from conventional acoustic analogy - based models , and with measurements obtained from wind tunnel and flight tests for the MD-902 helicopter at several operating conditions . Findings show that the direct CFD approach is quite successfully in yielding low frequency results due to thickness and steady loading noise mechanisms . Mid - to - high frequency contents , due to blade - vortex interactions , are not predicted due to CFD modeling and grid constraints .
Interplanetary trajectory optimization problems are highly complex and are characterized by a large number of decision variables and equality and inequality constraints as well as many locally optimal solutions . Stochastic global search techniques , coupled with a large - scale NLP solver , have been shown to solve such problems but are inadequately robust when the problem constraints become very complex . In this work , we present a novel search algorithm that takes advantage of the fact that equality constraints effectively collapse the solution space to lower dimensionality . This new approach walks the filament '' of feasibility to efficiently find the global optimal solution .
This paper describes the application of the MUSE multiobjecctive scheduling framework to the Cluster II WBD scheduling domain . Cluster II is an ESA four - spacecraft constellation designed to study the plasma environment of the Earth and it 's magnetosphere . One of the instruments on each of the four spacecraft is the Wide Band Data ( WBD ) plasma wave experiment . We have applied the MUSE evolutionary algorithm to the scheduling problem represented by this instrument , and the result has been adopted and utilized by the WBD schedulers for nearly a year . This paper describes the WBD scheduling problem , its representation in MUSE , and some of the visualization elements that provide insight into objective value tradeoffs .
A linear - elasticity approach is presented for the generation of meshes appropriate for a higher - order space - time discontinuous finite - element method . The equations of linear - elasticity are discretized using a higher - order , spatially - continuous , finite - element method . Given an initial finite - element mesh , and a specified boundary displacement , we solve for the mesh displacements to obtain a higher - order curvilinear mesh . Alternatively , for moving - domain problems we use the linear - elasticity approach to solve for a temporally discontinuous mesh velocity on each time - slab and recover a continuous mesh deformation by integrating the velocity . The applicability of this methodology is presented for several benchmark test cases .
In an effort to minimize the need for costly , complex , tracking radars , the German Space Operations Center has set up a research project for GPS based tracking of sounding rockets . As part of this project , a GPS receiver based on commercial technology for terrestrial applications has been modified to allow its use under the highly dynamical conditions of a sounding rocket flight . In addition , new antenna concepts are studied as an alternative to proven but costly wrap - around antennas .
This paper reports on two advanced measurement devices for the microgravity electromagnetic levitation facility ( EML ) , which is currently under construction for the use onboard the " International Space Station ( ISS ) " : the " Sample Coupling Electronics ( SCE ) " and the " Oxygen Sensing and Control Unit ( OSC ) " . The SCE measures by a contactless , inductive method the electrical resistivity and the diameter of a spherical levitated metallic droplet by evaluating the voltage and electrical current applied to the levitation coil . The necessity of the OSC comes from the insight that properties like surface tension or , eventually , viscosity can not seriously be determined by the oscillating drop method in the EML facility without knowing the conditions of the surrounding atmosphere . In the following both measurement devices are explained and laboratory test results are presented .
The effect of finite span on the jet - surface interaction noise source and the jet mixing noise shielding and reflection effects is considered using recently acquired experimental data . First , the experimental setup and resulting data are presented with particular attention to the role of surface span on far - field noise . These effects are then included in existing empirical models that have previously assumed that all surfaces are semi - infinite . This extended abstract briefly describes the experimental setup and data leaving the empirical modeling aspects for the final paper .
A prototype digital signal processing ( DSP ) algorithm has been developed to approximate Florida scrub jay calls . The Florida scrub jay ( Aphelocoma coerulescens ) , believed to have been in existence for 2 million years , living only in Florida , has a complicated social system that is evident by examining the spectrograms of its calls . Audio data was acquired at the Helen and Allan Cruickshank Sanctuary , Rockledge , Florida during the 2016 mating season using three digital recorders sampling at 44.1 kHz . The synthesis algorithm is a first step at developing a robust identification and call analysis algorithm . Since the Florida scrub jay is severely threatened by loss of habitat , it is important to develop effective methods to monitor their threatened population using autonomous means .
Future human exploration of the moon will require the development of capabilities for in - situ resource utilization ( ISRU ) . Transport of lunar - derived commodities such as fuel and oxygen to orbiting resource depots has been proposed to enable refueling landers or other vehicles . A lunar electromagnetic launch ( LEML ) system could be an effective means of transporting materials , as an alternative to non - renewable chemical - based propulsion systems . An example LEML concept is presented based on previous studies , existing EML technologies , and NASA 's human exploration architecture . A preliminary assessment of the cost - versus - benefit of such a system is also offered ; the conclusion , however , is not as favorable for LEML as originally suggested .
We propose to apply the technique of synthetic aperture radar interferometry to the measurement of ocean surface topography at spatial resolution approaching 1 km . The measurement will have wide ranging applications in oceanography , hydrology . and marine geophysics . The oceanographic and related societal applications are briefly discussed in the paper . To meet the requirements for oceanographic applications , the instrument must be flown in an orbit with proper sampling of ocean tides .
The design and performance of a highly reliable , 20 volt nickel hydrogen battery compatible with existing NiCad Mars observer based spacecraft components and an 800 psi , zirconium wall wick Common Pressure Vessel ( CPV ) are discussed . The objectives of the design process are : to meet or exceed all PD requirements by using existing technologies ; to have high reliability hardware and parallel fabrication of components ; and low schedule risk configurations . This paper discusses the tests performed on the batteries ( capacity , charge retention , random vib . , pyro shock , energy density , and packing factor ) and the results of the tests . In addition to the design discussion , a brief introduction on Mars Global Surveyor ( MGS ) Satellite objectives ( NASA 's next interplanetary mission ) is also presented .
Intrauterine complications have been implicated in the etiology of neuripsychiatric disorders including schizophrenia , autism and ADHD . This presentation will describe new translational studies derived from in vivo magnetic resonance imaging of developing and adult brain following perinatal asphyxia ( PA ) . Our findings reveal significant effects of PA on neurometabolic profiles at one week of age , and significant relationships between early metabolites and later life phenotypes including behavior and brain morphometry
A thermal model for predicting and designing the furnace temperature profile was developed and used for the crystal growth of lead bromide . The model gives the ampoule temperature as a function of the furnace temperature , thermal conductivity , heat transfer coefficients , and ampoule dimensions as variable parameters . Crystal interface curvature was derived from the model and it was compared with the predicted curvature for a particular furnace temperature and growth parameters . Large crystals of lead bromide were grown and it was observed that interface shape was in agreement with the shape predicted by this model .
A derivation of turbulent flow parameters , combined with data from erosive burning test motors and blowing wall tests results in erosive burning model candidates useful in one - dimensional internal ballistics analysis capable of scaling across wide ranges of motor size . The real - time burn rate data comes from three test campaigns of subscale segmented solid rocket motors tested at two facilities . The flow theory admits the important effect of the blowing wall on the turbulent friction coefficient by using blowing wall data to determine the blowing wall friction coefficient . The erosive burning behavior of full - scale motors is now predicted more closely than with other recent models .
The Orion spacecraft will be required to perform a three - burn trans - Earth injection ( TEI ) maneuver sequence to return to Earth from low lunar orbit . The origin of this approach lies in the Constellation Program requirements for access to any lunar landing site location combined with anytime lunar departure . This paper documents the development of optimized databases used to rapidly model the performance requirements of the TEI three - burn sequence for an extremely large number of mission cases . It also discusses performance results for lunar departures covering a complete 18.6 year lunar nodal cycle as well as general characteristics of the optimized three - burn TEI sequence .
This viewgraph presentation reviews the vision of the   sensor web enablement via a Service Oriented Architecture ( SOA ) . An generic example is given of a user finding a service through the Web , and initiating a request for the desired observation .   The parts that comprise this system and how they interact are reviewed .   The advantages of the use of SOA are reviewed .
Graphitization of carbon is an irreversible process which alters the structure of graphitic materials in response to the increase in metamorphic grade ( temperature and/or pressure ) . Carbonaceous materials offer a reliable geothermometer as their Raman spectra change systematically with increasing metamorphic grade . In this study , we identified carbonaceous materials in the xenolithic clasts in Sharps and interpreted their metamorphic history by revealing the structural organization ( order ) of the polyaromatic organic phases using micro - Raman spectroscopy .
Three - dimensional Direct Simulation Monte Carlo simulations of Columbia Shuttle Orbiter flight STS-107 are presented . The aim of this work is to determine the aerodynamic and heating behavior of the Orbiter during aerobraking maneuvers and to provide piecewise integration of key scenario events to assess the plausibility of the candidate failure scenarios . The flight of the Orbiter is examined at two altitudes : 350 - kft and 300 - kft . The flowfield around the Orbiter and the heat transfer to it are calculated for the undamaged configuration . The flow inside the wing for an assumed damage to the leading edge in the form of a 10- inch hole is studied .
The problem of propagation of sound across the shear layer in a turbofan jet exhaust with an external center - body is discussed . The wave equation of interest is the compressible Rayleigh equation . Two forms of the equation are considered , and the Green 's function solutions , subject to appropriate surface conditions on the center - body and flight condition in the ambient , are presented . Directivity studies in a heated exhaust at temperature ratio of 2.0 and Mach number 0.90 indicate that a rigid center - body tends to increase the sound propagation at forward angles relative to an exhaust without a center - body , while application of suitable surface liner may significantly reduce this enhancement .
The Aquarius / SAC - D mission will employ three L - band ( 1.41 GHz ) radiometers dedicated to remote sensing of Sea Surface Salinity . The mission will be in a dawn / dusk sun - synchronous orbit with the beam oriented toward the night time side of the orbit in order to limit interference from the Sun . The effect of surface roughness on solar radiation reflected from the surface will be examined . It will be shown that including the small scale roughness ( waves ) can have a major impact . Also , it will be shown that when the small scale waves are included it is possible to have significant radiation reflected into the main beam during seasonal extremes when a portion of the main beam is on the illuminated side of day - night terminator .
In 1996 , a team of government , university and industry researchers proposed a program to seek the ultimate breakthroughs in space transportation : propulsion that requires no propellant mass , propulsion that can approach and , if possible , circumvent light speed , and breakthrough methods of energy production to power such devices . This Breakthrough Propulsion Physics program , managed by Lewis Research Center , is one part of a comprehensive , long range Advanced Space Transportation Plan managed by Marshall Space Flight Center . Because the breakthrough goals are beyond existing science , a main emphasis of this program is to establish metrics and ground rules to produce near - term credible progress toward these incredible possibilities . An introduction to the emerging scientific possibilities from which such solutions can be sought is also presented .
We report , for the first time , an epitaxially grown InP p(+)/n(++ ) tunnel junction . A diode with peak current densities up to 1600 A / cm and maximum specific resistivities ( Vp / Ip - peak voltage to peak current ratio ) in the range of 10(exp -4)Omega cm(exp 2 ) is obtained . This peak current density is comparable to the highest results previously reported for lattice matched In(0.53)Ga(0.47)As tunnel junctions . Both results were obtained using chemical beam epitaxy ( CBE ) . In this paper we discuss the electrical characteristics of these tunnel diodes and how the growth conditions influence them .
Abstract In the control - based approach to robotics , complex behavior is created by sequencing and combining control primitives . While it is desirable for the robot to autonomously learn the correct control sequence , searching through the large number of potential solutions can be time consuming . This paper constrains this search to variations of a generalized solution encoded in a framework known as an action schema . A new algorithm , SCHEMA STRUCTURED LEARNING , is proposed that repeatedly executes variations of the generalized solution in search of instantiations that satisfy action schema objectives . This approach is tested in a grasping task where Dexter , the UMass humanoid robot , learns which reaching and grasping controllers maximize the probability of grasp success .
The Mid - Lift - to - Drag Ratio Rigid Vehicle ( MRV ) is a proposed candidate in the NASA Evolvable Mars Campaign 's ( EMC ) Pathfinder Entry , Descent , and Landing ( EDL ) architecture study . The purpose of the study is to design a mission and vehicle capable of transporting a 20mt payload to the surface of Mars . The MRV is unique in its rigid , asymmetrical lifting - body shape which enables a higher lift - to - drag ratio ( L / D ) than the typical robotic Mars entry capsule vehicles that carry much less mass . This paper presents the formulation and six - degree - of - freedom ( 6DOF ) performance of the MRV 's control system , which uses both aerosurfaces and a propulsive reaction control system ( RCS ) to affect longitudinal and lateral directional behavior .
Millimeter wave imaging techniques can provide high spatial - resolution images of various composites . Lens antennas may be incorporated into the imaging system to provide a small incident beam footprint . Another approach may involve the use of horn antennas , which if operating in their near - fields , images with reasonably high spatial - resolutions may also be obtained . This paper gives a comparison between such near - field and focused far - field imaging of the Space Shuttle Spray on Foam Insulation ( SOFI ) used in its external fuel tank at millimeter wave frequencies . Small horn antennas and lens antennas with relatively long depth of focus were used in this investigation .
A General Overview of NASA Advanced Transportation Technologies Program is presented . The contents include : 1 ) Center - TRACON Automation System ( CTAS ) which provides automation tools to assist air traffic controllers in planning and controlling air traffic arriving into major airports ; 2 ) Surface Movement Advisor ( SMA ) for expediting and optimizing aircraft operations on the airport surface ; and 3 ) Terminal Area Productivity Program ( TAP ) , which is aimed at improving airport throughput in instrument meteorological conditions to match that attainable in clear weather .
This slide presentation reviews the modeling activities for modeling of the long - term debris environment , the updated assessments of the environment , and the necessity to model the effectiveness of the technologies aimed at the removal of orbital debris . The model being used is named a LEO to GEO environment debris ( LEGEND ) . It is a high fidelity three dimensional numerical simulation model with the capability to treat objects individually . It uses a Monte Carlo approach and a collision probability evaluation algorithm to simulate future satellite breakups and the growth of the debris populations .