SEARCH · Engineering Papers

Results for “SPACECRAFT PERFORMANCE”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records

All sources NASA NTRS DOE OSTI

DOE OSTI2012

SPECTROSCOPIC SIGNATURE OF ALFVEN WAVES DAMPING IN A POLAR CORONAL HOLE UP TO 0.4 SOLAR RADII

Between 2009 February 24 and 25, the EUV Imaging Spectrometer (EIS) spectrometer on board the Hinode spacecraft performed special 'sit and stare' observations above the south polar coronal hole continuously over more than 22 hr. Spectra were acquired with the 1'' slit placed off-limb covering altitudes up to 0.48 R{sub Sun} (3.34 Multiplication-Sign 10{sup 2} Mm) above the Sun surface, in order to study with EIS the non-thermal spectral line broadenings. Spectral lines such as Fe XII {lambda}186.88, Fe XII {lambda}193.51, Fe XII {lambda}195.12, and Fe XIII {lambda}202.04 are observed with good statistics up to high altitudes and they have been analyzed in this study. Results show that the FWHM of the Fe XII {lambda}195.12 line increases up to {approx_equal} 0.14 R{sub Sun }, then decreases higher up. EIS stray light has been estimated and removed. Derived electron density and non-thermal velocity profiles have been used to estimate the total energy flux transported by Alfven waves off-limb in the polar coronal hole up to {approx_equal} 0.4 R{sub Sun }. The computed Alfven wave energy flux density f{sub w} progressively decays with altitude from f{sub w} {approx_equal} 1.2 Multiplication-Sign 10{sup 6} erg cm{sup -2} s{sup -1} at 0.03 R{sub Sun} down to f{sub w} {approx_equal} 8.5 Multiplication-Sign 10{sup 3} erg cm{sup -2} s{sup -1} at 0.4 R{sub Sun }, with an average energy decay rate of {Delta}f{sub w} /{Delta}h {approx_equal} -4.5 Multiplication-Sign 10{sup -5} erg cm{sup -1}. Hence, this result suggests energy deposition by Alfven waves in a polar coronal hole, thus providing a significant source for coronal heating.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2012

Plasma transport induced by kinetic Alfven wave turbulence

At the Earth's magnetopause that separates the hot-tenuous magnetospheric plasma from the cold dense solar wind plasma, often seen is a boundary layer where plasmas of both origins coexist. Plasma diffusions of various forms have been considered as the cause of this plasma mixing. Here, we investigate the plasma transport induced by wave-particle interaction in kinetic Alfven wave (KAW) turbulence, which is one of the candidate processes. We clarify that the physical origin of the KAW-induced cross-field diffusion is the drift motions of those particles that are in Cerenkov resonance with the wave: E Multiplication-Sign B-like drift that emerges in the presence of non-zero parallel electric field component and grad-B drift due to compressional magnetic fluctuations. We find that KAW turbulence, which has a spectral breakpoint at which an MHD inertial range transits to a dissipation range, causes selective transport for particles whose parallel velocities are specified by the local Alfven velocity and the parallel phase velocity at the spectral breakpoint. This finding leads us to propose a new data analysis method for identifying whether or not a mixed plasma in the boundary layer is a consequence of KAW-induced transport across the magnetopause. The method refers to the velocity space distribution function data obtained by a spacecraft that performs in situ observations and, in principle, is applicable to currently available dataset such as that provided by the NASA's THEMIS mission.

58 GEOSCIENCES↗

DOE OSTI2015

New scientific equipment for protein crystallization in microgravity, BELKA, and its approbation on the Bion-M No. 1 spacecraft

A space experiment on the crystallization of lisozyme and glucose isomerase proteins in UK-1 and UK-2 crystallizers on the scientific equipment BELKA on the Bion-M no. 1 spacecraft was performed in April–May 2013. A ground-based experiment was carried out simultaneously at the Institute of Crystallography of the Russian Academy of Sciences (IC RAS). Transparent crystals were obtained in both cases. The lisozyme crystals grown in microgravity are larger than their terrestrial analogs. An optical study of glucose isomerase crystals grown in space has shown that the coalescence of equally oriented crystallites leads to the formation of quasi-single-crystal blocks. An X-ray diffraction experiment on lisozyme crystals has revealed the resolutions for crystals obtained under terrestrial conditions and in space to be 1.74 and 1.58 Å, respectively.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2018

Simulation of Space Experiments for Nuclear Planetology: Measurement of Relative Intensities of Lines of Gamma Ray Emitted upon Thermal-Neutron Capture by Nuclei

The results obtained by experimentally studying gamma rays emitted by samples prepared as analogs of planetary matter and irradiated with thermal neutrons are presented. The intensities of spectral lines of gamma rays emitted by such samples differing in chemical composition are compared. These results will be used in processing data on gamma-ray spectra of the Moon and Mercury from measurements performed onboard spacecrafts with the aim of studying the composition of the surface of these celestial bodies.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2015

THE HELIOTAIL

The heliotail is formed when the solar wind (SW) interacts with the local interstellar medium (LISM) and is shaped by the interstellar magnetic field (ISMF). While there are no spacecraft available to perform in situ measurements of the SW plasma and heliospheric magnetic field (HMF) in the heliotail, it is of importance for the interpretation of measurements of energetic neutral atom fluxes performed by Interstellar Boundary Explorer. It has been shown recently that the orientation of the heliotail in space and distortions of the unperturbed LISM caused by its presence may explain the anisotropy in the TeV cosmic ray flux detected in air shower observations. The SW flow in the heliotail is a mystery itself because it is strongly affected by charge exchange between the SW ions and interstellar neutral atoms. If the angle between the Sun’s magnetic and rotation axes is constant, the SW in the tail tends to be concentrated inside the HMF spirals deflected tailward. However, the twisted field soon becomes unstable and the reason for the SW collimation within a two-lobe structure vanishes. We demonstrate that kinetic treatment of the H atom transport becomes essential in this case for explaining the lobe absence further along the tail. We show that the heliotail flow is strongly affected by the solar cycle that eliminates artifacts, which is typical of solutions based on simplifying assumptions. The heliopause in the tail is subject to Kelvin–Helmholtz instability, while its orientation and shape are determined by the ISMF direction and strength.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2024

Electron energization in reconnection: Eulerian vs Lagrangian perspectives

Particle energization due to magnetic reconnection is an important unsolved problem for myriad space and astrophysical plasmas. Electron energization in magnetic reconnection has traditionally been examined from a particle, or Lagrangian, perspective using particle-in-cell (PIC) simulations. Guiding-center analyses of ensembles of PIC particles have suggested that Fermi (curvature drift) acceleration and direct acceleration via the reconnection electric field are the primary electron energization mechanisms. However, both PIC guiding-center ensemble analyses and spacecraft observations are performed in an Eulerian perspective. For this work, we employ the continuum Vlasov–Maxwell solver within the Gkeyll simulation framework to reexamine electron energization from a kinetic continuum, Eulerian, perspective. We separately examine the contribution of each drift energization component to determine the dominant electron energization mechanisms in a moderate guide-field Gkeyll reconnection simulation. In the Eulerian perspective, we find that the diamagnetic and agyrotropic drifts are the primary electron energization mechanisms away from the reconnection x-point, where direct acceleration dominates. We compare the Eulerian (Vlasov Gkeyll) results with the wisdom gained from Lagrangian (PIC) analyses.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

DOE OSTI2024

Identification of Kelvin-Helmholtz generated vortices in magnetised fluids

The Kelvin-Helmholtz Instability (KHI), arising from velocity shear across the magnetopause, plays a significant role in the viscous-like transfer of mass, momentum, and energy from the shocked solar wind into the magnetosphere. While the KHI leads to growth of surface waves and vortices, suitable detection methods for these applicable to magnetohydrodynamics (MHD) are currently lacking. A novel method is derived based on the well-established λ-family of hydrodynamic vortex identification techniques, which define a vortex as a local minimum in an adapted pressure field. The J × B Lorentz force is incorporated into this method by using an effective total pressure in MHD, including both magnetic pressure and a pressure-like part of the magnetic tension derived from a Helmholtz decomposition. The λ MHD method is shown to comprise of four physical effects: vortical momentum, density gradients, fluid compressibility, and the rotational part of the magnetic tension. A local three-dimensional MHD simulation representative of near-flank magnetopause conditions (plasma β’s 0.5 – 5 and convective Mach numbers M f ∼ 0.4) under northward interplanetary magnetic field (IMF) is used to validate λ MHD . Analysis shows it correlates well with hydrodynamic vortex definitions, though the level of correlation decreases with vortex evolution. Overall, vortical momentum dominates λ MHD at all times. During the linear growth phase, density gradients act to oppose vortex formation. By the highly nonlinear stage, the formation of small-scale structures leads to a rising importance of the magnetic tension. Compressibility was found to be insignificant throughout. Finally, a demonstration of this method adapted to tetrahedral spacecraft observations is performed.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2016

AN ADJOINT-BASED METHOD FOR THE INVERSION OF THE JUNO AND CASSINI GRAVITY MEASUREMENTS INTO WIND FIELDS

During 2016–17, the Juno and Cassini spacecraft will both perform close eccentric orbits of Jupiter and Saturn, respectively, obtaining high-precision gravity measurements for these planets. These data will be used to estimate the depth of the observed surface flows on these planets. All models to date, relating the winds to the gravity field, have been in the forward direction, thus only allowing the calculation of the gravity field from given wind models. However, there is a need to do the inverse problem since the new observations will be of the gravity field. Here, an inverse dynamical model is developed to relate the expected measurable gravity field, to perturbations of the density and wind fields, and therefore to the observed cloud-level winds. In order to invert the gravity field into the 3D circulation, an adjoint model is constructed for the dynamical model, thus allowing backward integration. This tool is used for the examination of various scenarios, simulating cases in which the depth of the wind depends on latitude. We show that it is possible to use the gravity measurements to derive the depth of the winds, both on Jupiter and Saturn, also taking into account measurement errors. Calculating the solution uncertainties, we show that the wind depth can be determined more precisely in the low-to-mid-latitudes. In addition, the gravitational moments are found to be particularly sensitive to flows at the equatorial intermediate depths. Therefore, we expect that if deep winds exist on these planets they will have a measurable signature by Juno and Cassini.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2012

A GLOBAL TWO-TEMPERATURE CORONA AND INNER HELIOSPHERE MODEL: A COMPREHENSIVE VALIDATION STUDY

The recent solar minimum with very low activity provides us a unique opportunity for validating solar wind models. During CR2077 (2008 November 20 through December 17), the number of sunspots was near the absolute minimum of solar cycle 23. For this solar rotation, we perform a multi-spacecraft validation study for the recently developed three-dimensional, two-temperature, Alfven-wave-driven global solar wind model (a component within the Space Weather Modeling Framework). By using in situ observations from the Solar Terrestrial Relations Observatory (STEREO) A and B, Advanced Composition Explorer (ACE), and Venus Express, we compare the observed proton state (density, temperature, and velocity) and magnetic field of the heliosphere with that predicted by the model. Near the Sun, we validate the numerical model with the electron density obtained from the solar rotational tomography of Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph C2 data in the range of 2.4 to 6 solar radii. Electron temperature and density are determined from differential emission measure tomography (DEMT) of STEREO A and B Extreme Ultraviolet Imager data in the range of 1.035 to 1.225 solar radii. The electron density and temperature derived from the Hinode/Extreme Ultraviolet Imaging Spectrometer data are also used to compare with the DEMT as well as the model output. Moreover, for the first time, we compare ionic charge states of carbon, oxygen, silicon, and iron observed in situ with the ACE/Solar Wind Ion Composition Spectrometer with those predicted by our model. The validation results suggest that most of the model outputs for CR2077 can fit the observations very well. Based on this encouraging result, we therefore expect great improvement for the future modeling of coronal mass ejections (CMEs) and CME-driven shocks.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2021

MULTI-MISSION THERMOELECTRIC GENERATOR ASSEMBLY TESTING AND LAUNCH OPERATIONS FOR MARS 2020

The Space Nuclear Power and Isotope Technologies (SNPIT) division at Idaho National Laboratory (INL) fuels, performs acceptance testing, and provides spacecraft integration support of Radioisotope Power Systems (RPS) in support of National Aeronautics and Space Administration (NASA) missions. Recently the SNPIT team completed assembly, testing and launch support of the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) for the Mars 2020 Perseverance Rover mission.

07 ISOTOPE AND RADIATION SOURCES↗

DOE OSTI2021

MULTI-MISSION THERMOELECTRIC GENERATOR ASSEMBLY TESTING AND LAUNCH OPERATIONS FOR MARS 2020

07 ISOTOPE AND RADIATION SOURCES↗

DOE OSTI2015

Future beam experiments in the magnetosphere with plasma contactors: How do we get the charge off the spacecraft?

Abstract The idea of using a high‐voltage electron beam with substantial current to actively probe magnetic field line connectivity in space has been discussed since the 1970s. However, its experimental realization onboard a magnetospheric spacecraft has never been accomplished because the tenuous magnetospheric plasma cannot provide the return current necessary to keep spacecraft charging under control. In this work, we perform Particle‐In‐Cell simulations to investigate the conditions under which a high‐voltage electron beam can be emitted from a spacecraft and explore solutions that can mitigate spacecraft charging. The electron beam cannot simply be compensated for by an ion beam of equal current, because the Child‐Langmuir space charge limit is violated under conditions of interest. On the other hand, releasing a high‐density neutral contactor plasma prior and during beam emission is critical in aiding beam emission. We show that after an initial transient controlled by the size of the contactor cloud where the spacecraft potential rises, the spacecraft potential can settle into conditions that allow for electron beam emission. A physical explanation of this result in terms of ion emission into spherical geometry from the surface of the plasma cloud is presented, together with scaling laws of the peak spacecraft potential varying the ion mass and beam current. These results suggest that a strategy where the contactor plasma and the electron beam operate simultaneously might offer a pathway to perform beam experiments in the magnetosphere.

Delzanno, G. L.↗

DOE OSTI2018

Study of Gamma-ray Production from Neutron-induced Activity on Spacecraft for DIORAMA

The Distributed Infrastructure Offering Real{Time Access to Modeling and Analysis (DIORAMA) software provides performance modeling capabilities of the United States Nuclear Detonation Detection System (USNDS) with a focus on the characterization of Space{Based Nuclear Detonation Detection (SNDD) instrument performance [1]. A study was conducted investigating the neutron activation on spacecraft caused by cosmic{ray and trapped proton{induced spallation, and by direct irradiation from hypothetical nuclear detonations as a background component to be incorporated into DIORAMA. The neutron activation background study amasses a database of pre-calculated Monte Carlo data that reflects the delayed gamma-ray production from activated nuclei as a function of incident cosmic or neutron flux, incident energy, material volume, etc. CINDER2008 coupled with MCNPX and the Activation Analysis Tools in the Activation in Accelerator Radiation Environments (AARE) distribution along with a suite of Python scripts are used to calculate and assemble the Monte Carlo database [2{6]. The neutron activation background study improves the fidelity of DIORAMA by providing the neutron-induced activation component to the background of the instruments on-board the spacecraft, and has implications for future instrument design studies.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2015

A FULL STUDY ON THE SUN–EARTH CONNECTION OF AN EARTH-DIRECTED CME MAGNETIC FLUX ROPE

We present an investigation of an eruption event of a coronal mass ejection (CME) magnetic flux rope (MFR) from the source active region (AR) NOAA 11719 on 2013 April 11 utilizing observations from the Solar Dynamic Observatory, the Solar Terrestrial Relations Observatory, the Solar and Heliospheric Observatory, and the WIND spacecraft. The source AR consists of a pre-existing sigmoidal structure stacked over a filament channel which is regarded as an MFR system. EUV observations of low corona suggest further development of this MFR system by added axial flux through tether-cutting reconnection of loops at the middle of the sigmoid under the influence of continuous slow flux motions for two days. Our study implies that the MFR system in the AR is initiated to upward motion by kink instability and further driven by torus instability. The CME morphology, captured in simultaneous three-point coronagraph observations, is fitted with a Graduated Cylindrical Shell (GCS) model and discerns an MFR topology with its orientation aligning with a magnetic neutral line in the source AR. This MFR expands self-similarly and is found to have source AR twist signatures in the associated near-Earth magnetic cloud (MC). We further derived the kinematics of this CME propagation by employing a plethora of stereoscopic as well as single-spacecraft reconstruction techniques. While stereoscopic methods perform relatively poorly compared to other methods, fitting methods worked best in estimating the arrival time of the CME compared to in situ measurements. Supplied with the values of constrained solar wind velocity, drag parameter, and three-dimensional kinematics from the GCS fit, we construct CME kinematics from the drag-based model consistent with in situ MC arrival.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2013

Modal survey test and model correlation of the CASSIOPE spacecraft

A comprehensive modal survey test based on multi-input multi-output experimental modal analysis techniques was conducted on the flight model of the CASSIOPE spacecraft in the final stages of integration, which included all of the payload and bus instruments and electronics boxes. The multiple-input excitation for the spacecraft was generated using two portable electrodynamic modal shakers installed on the top and bottom of the spacecraft to distribute the excitation energy and the response was measured using 81 miniature accelerometers. Advanced modal analysis software was used to extract modal parameters from the measured data and critical modes were compared with predictions from the finite element model. Most modes identified through the experimental data compared favorably with the predictions. Nevertheless, some differences were large enough to require iterative update of the finite element model. The structural dynamics information from the updated finite element model was used to plan the mechanical vibration qualification test and predict the response of the spacecraft to the launch vehicle environmental loads through coupled loads analysis to provide confidence in the structural integrity of the spacecraft design. This paper describes the details of the methodology used to perform the successful experimental modal test to efficiently extract the critical modes of the spacecraft to correlate with the model.

42 ENGINEERING↗

DOE OSTI2017

In situ X-ray diffraction measurement of shock-wave-driven twinning and lattice dynamics

We report that pressure-driven shock waves in solid materials can cause extreme damage and deformation. Understanding this deformation and the associated defects that are created in the material is crucial in the study of a wide range of phenomena, including planetary formation and asteroid impact sites, the formation of interstellar dust clouds, ballistic penetrators, spacecraft shielding and ductility in high-performance ceramics. At the lattice level, the basic mechanisms of plastic deformation are twinning (whereby crystallites with a mirror-image lattice form) and slip (whereby lattice dislocations are generated and move), but determining which of these mechanisms is active during deformation is challenging. Experiments that characterized lattice defects have typically examined the microstructure of samples after deformation, and so are complicated by post-shock annealing and reverberations. In addition, measurements have been limited to relatively modest pressures (less than 100 gigapascals). In situ X-ray diffraction experiments can provide insights into the dynamic behaviour of materials, but have only recently been applied to plasticity during shock compression and have yet to provide detailed insight into competing deformation mechanisms. Here we present X-ray diffraction experiments with femtosecond resolution that capture in situ, lattice-level information on the microstructural processes that drive shock-wave-driven deformation. To demonstrate this method we shock-compress the body-centred-cubic material tantalum—an important material for high-energy-density physics owing to its high shock impedance and high X-ray opacity. Tantalum is also a material for which previous shock compression simulations and experiments have provided conflicting information about the dominant deformation mechanism. Our experiments reveal twinning and related lattice rotation occurring on the timescale of tens of picoseconds. In addition, despite the common association between twinning and strong shocks, we find a transition from twinning to dislocation-slip-dominated plasticity at high pressure (more than 150 gigapascals), a regime that recovery experiments cannot accurately access. Lastly, the techniques demonstrated here will be useful for studying shock waves and other high-strain-rate phenomena, as well as a broad range of processes induced by plasticity.

36 MATERIALS SCIENCE↗

DOE OSTI2024

The NASA ISRO SAR (NISAR) Mission - Validation of Science Measurement Requirements

The NASA ISRO Synthetic Aperture Radar (NISAR) is scheduled for launch early in 2024 from the Satish Dhawan Space Centre (SDSC), at Sriharikota, near Chennai, India. This mission is the result of a collaboration between NASA and Indian Space Research Organization (ISRO), where NASA has contributed elements of the mission such as an L-band SAR, and ISRO has contributed other elements, such as an S-band SAR. After successful launch, the NISAR mission will collect left-looking L-band SAR data over most of the Earth’s land areas twice during every 12-day exact repeat orbit. (once while in an ascending orbit direction and once while in a descending orbit direction). NASA and ISRO have individual and joint requirements on the mission that include the performance of the imaging radars onboard the spacecraft. For example, NASA must demonstrate that this L-band SAR will achieve a set of identified science measurement accuracy requirements that span Ecosystem science, Solid Earth science, and Cryosphere science disciplines. Likewise, ISRO has several applications objectives on both the L-band and S-band data from NISAR that the ISRO science team and project will be developing and testing. Pre-launch and post-launch activities have been planned to validate that these requirements are met. Here, we will discuss how the NASA plans are being executed and will present any initial results at the conference.

Chapman, Bruce↗

DOE OSTI2015

Future beam experiments in the magnetosphere with plasma contactors: The electron collection and ion emission routes

Experiments where a high-voltage electron beam emitted by a spacecraft in the low-density magnetosphere is used to probe the magnetospheric configuration could greatly enhance our understanding of the near-Earth environment. Their challenge, however, resides in the fact that the background magnetospheric plasma cannot provide a return current that balances the electron beam current without charging the spacecraft to such high potential that in practice prevents beam emission. In order to overcome this problem, a possible solution is based on the emission of a high-density contactor plasma by the spacecraft prior to and after the beam. In this paper, we perform particle-in-cell simulations to investigate the conditions under which a high-voltage electron beam can be emitted from a magnetospheric spacecraft, comparing two possible routes that rely on the high-density contactor plasma. The first is an “electron collection” route, where the contactor has lower current than the electron beam and is used with the goal of connecting to the background plasma and collecting magnetospheric electrons over a much larger area than that allowed by the spacecraft alone. The second is an “ion emission” route, where the contactor has higher current than the electron beam. Ion emission is then enabled over the large quasi-spherical area of the contactor cloud, thus overcoming the space charge limits typical of ion beam emission. Finally, our results indicate that the ion emission route offers a pathway for performing beam experiments in the low-density magnetosphere, while the electron collection route is not viable because the contactor fails to draw a large neutralizing current from the background.

79 ASTRONOMY AND ASTROPHYSICS↗