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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.

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At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Nucleon structure studies: DVCS on polarised protons with the CLAS12 experiment, and development of Micromegas detectors for EIC

The quark and gluon structure of nucleons is crucial for understanding the origin of their mass and spin. This information is encoded in structure function such as Generalised Parton Distributions (GPDs), which provide a three-dimensional picture of the nucleon in terms of its constituents. Deeply Virtual Compton Scattering (DVCS) offers the most direct access to GPDs, but their extraction requires high-precision measurements of multiple observables over a wide kinematic range. In 2022 and 2023 the CLAS12 experiment at Jefferson Lab (JLab) collected data from polarised electron scattering on a longitudinally polarised proton target, enabling the first measurement of polarised DVCS asymmetries at JLab 12GeV kinematics. This thesis will present preliminary measurement of the beam, target and double spin DVCS asymmetries from the CLAS12 polarised proton target data. Nucleon structure studies will also constitute a major part of the physics program at the future Electron Ion Collider (EIC). The development of the first detector at the EIC is ongoing and it requires light Micro-Pattern Gaseous Detectors (MPGDs) for its tracking system. This thesis further reports initial tests of Micromegas MPGDs with a two-dimensional readout developed for EIC.

Polcher, Samy [Univ. Paris-Saclay, Gif-sur-Yvette ↗
NASA NTRS1981

Faraday rotation measurement method and apparatus

A method and device for measuring Faraday rotation of a received RF signal is described. A simultaneous orthogonal polarization receiver compensates for a 3 db loss due to splitting of a received signal into left circular and right circular polarization channels. The compensation is achieved by RF and modulation arraying utilizing a specific receiver array which also detects and measures Faraday rotation in the presence or absence of spin stabilization effects on a linear polarization vector. Either up-link or down-link measurement of Faraday rotation is possible. Specifically, the Faraday measurement apparatus utilized in conjunction with the specific receiver array provides a means for comparing the phase of a reference signal in the receiver array to the phase of a tracking loop signal related to the incoming signal, and comparing the phase of the reference signal to the phase of the tracking signal shifted in phase by 90 degrees. The averaged and unaveraged signals, are compared, the phase changes between the two signals being related to Faraday rotation.

Brockman, M. H.↗
NASA NTRS2011

The Dawn Gravity Investigation at Vesta and Ceres

The objective of the Dawn gravity investigation is to use high precision X-band Doppler tracking and landmark tracking from optical images to measure the gravity fields of Vesta and Ceres to a half-wavelength surface resolution better than 90-km and 300-km, respectively. Depending on the Doppler tracking assumptions, the gravity field will be determined to somewhere between harmonic degrees 15 and 25 for Vesta and about degree 10 for Ceres. The gravity fields together with shape models determined from Dawn's framing camera constrain models of the interior from the core to the crust. The gravity field is determined jointly with the spin pole location. The second degree harmonics together with assumptions on obliquity or hydrostatic equilibrium may determine the moments of inertia.

Vesta↗
NASA NTRS1991

Pioneer 6 through 8

The DSN (Deep Space Network) mission support requirements for Pioneer 6, 7 and 8 are summarized. The primary objective of these Pioneer missions is to collect scientific data relative to interplanetary phenomena within a range of approximately 0.8 to 1.2 astronomical units from the sun. Following orbital injection, each spacecraft was oriented with its spin axis normal to the ecliptic plane so that the high gain antenna pattern would be aligned with Earth's orbit. The mission objectives are outlined and the DSN support requirements are defined through the presentation of tables and narratives describing the spacecraft flight profiles; DSN support coverage; frequency assignments; support parameters for telemetry, command and support systems; and tracking support responsibility.

Lozier, D.↗
DOE OSTI2023

Experimental study of the S 38 excited level scheme

Information on the 38 S level scheme was expanded through experimental work utilizing a fusion-evaporation reaction and in-beam γ-ray spectroscopy. Prompt γ-ray transitions were detected by the Gamma-Ray Energy Tracking Array (GRETINA) and recoiling 38 S residues were selected by the Fragment Mass Analyzer (FMA). Tools based on machine-learning techniques were developed and deployed for the first time in order to enhance the unique selection of 38S residues and identify any associated γ-ray transitions. The new level information, including the extension of the even-spin yrast sequence through J π =8( + ), was interpreted in terms of a basic single-particle picture as well shell-model calculations which incorporated the empirically derived FSU interaction. A comparison between the properties of the yrast states in the even-Z, N = 22 isotones from Z = 14 to 20, and for 36 Si– 38 S in particular, was also presented with an emphasis on the role and influence of the neutron 1 p 3/2 orbital on the structure in the region.

20 ≤ A ≤ 38↗
NASA NTRS1972

Current concepts for a tracking and data relay satellite system.

Description of two varieties of a tracking and data relay satellite system utilizing geosynchronous relay spacecraft to provide telecommunications service to user spacecraft in low earth orbit. These users are categorized by their earth return data rates. The described system varieties are the two versions of a low and medium data rate system whose definition study is now complete. One of these versions utilizes a spin-stabilized spacecraft, while the other employs a three-axis stabilized one. Some of the communication problems peculiar to these system varieties are discussed.

Clark, G. Q.↗
DOE OSTI2026

Polarized Deep-Inelastic Scattering with Spin Correlations in Herwig 7

This repository is the research software and reproducibility companion for the HerwigPol polarized deep-inelastic scattering implementation developed for Herwig 7. It brings together the modified Herwig and ThePEG source snapshots, the curated POLDIS fixed-order reference code, the custom Rivet analyses, the DIS validation workflow, and the paper source in a single formal repository layout. The repository is intended to preserve the source-level ingredients needed to rebuild and re-run the validated DIS studies. It therefore tracks code, input cards, workflow drivers, and technical notes, while intentionally excluding generated artifacts such as build products, campaign outputs, merged YODA files, plots, and rendered paper outputs.

Papaefstathioou, Andreas [Kennesaw State Universit↗
DOE OSTI2020

Evolution of Radicals from the Photolysis of High Ionic Strength Alkaline Nitrite Solutions

Reactive nitrogen species (RNS), along with reactive oxygen species (ROS), are significant products from radiolysis in solution. While much research has been focused on biological systems, these species are also important products in the autoradiolysis that occurs in nuclear waste. In this work, we determine the correlation between solution constituents, particularly nitrite, and radical products in highly alkaline solutions relevant to liquid waste. Because these radicals tend to be very short-lived, we employ spin trapping in conjunction with electron paramagnetic resonance (EPR) to detect them and quantify their production. Most spin traps do not function in these conditions (>1 M NaOH); however, nitroalkanes such as nitromethane will act as spin traps in their aci form, which is dominant at high pH. To restrict the products to those originating from nitrite, we use 280–480 nm UV light to generate radicals, avoiding products from the photolysis of water. Under these circumstances, nitric oxide, nitrite radicals, and hydroxyl radicals are detected, and the trends with the concentration of the constituents of the solutions are tracked. These include nitrite, nitrate, hydroxide, and carbonate. We find that, while the equilibrium shifts with increasing pH from hydroxyl radicals to the more slowly reacting oxide radicals, the production of nitrite radicals does not decrease.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2005

Spinoff 2005

Topics covered include: Lighting the Way for Quicker, Safer Healing; Discovering New Drugs on the Cellular Level; Hydrogen Sensors Boost Hybrids; Today s Models Losing Gas?; 3-D Highway in the Sky; Popping a Hole in High-Speed Pursuits; Monitoring Wake Vortices for More Efficient Airports; From Rockets to Racecars; All-Terrain Intelligent Robot Braves Battlefront to Save Lives; Keeping the Air Clean and Safe--An Anthrax Smoke Detector; Lightning Often Strikes Twice; Technology That's Ready and Able to Inspect Those Cables; Secure Networks for First Responders and Special Forces; Space Suit Spins; Cooking Dinner at Home--From the Office; Nanoscale Materials Make for Large-Scale Applications; NASA s Growing Commitment: The Space Garden; Bringing Thunder and Lightning Indoors; Forty-Year-Old Foam Springs Back With New Benefits; Experiments With Small Animals Rarely Go This Well; NASA, the Fisherman's Friend; Crystal-Clear Communication a Sweet-Sounding Success; Inertial Motion-Tracking Technology for Virtual 3-D; Then Why Do They Call Earth the Blue Planet?; Valiant 'Zero-Valent' Effort Restores Contaminated Grounds; Harnessing the Power of the Sun; Water and Air Measures That Make 'PureSense'; Remote Sensing for Farmers and Flood Watching; Pesticide-Free Device a Fatal Attraction for Mosquitoes Making the Most of Waste Energy Washing Away the Worries About Germs Celestial Software Scratches More Than the Surface A Search Engine That's Aware of Your Needs Fault-Detection Tool Has Companies 'Mining' Own Business; Software to Manage the Unmanageable; Tracking Electromagnetic Energy With SQUIDs; Taking the Risk Out of Risk Assessment; Satellite and Ground System Solutions at Your Fingertips; Structural Analysis Made 'NESSUSary'; Software of Seismic Proportions Promotes Enjoyable Learning; Making a Reliable Actuator Faster and More Affordable; Cost-Cutting Powdered Lubricant NASA s Radio Frequency Bolt Monitor: A Lifetime of Spinoffs Going End to End to Deliver High-Speed Data; Advanced Joining Technology: Simple, Strong, and Secure; Big Results From a Smaller Gearbox; Low-Pressure Generator Makes Cleanrooms Cleaner; and The Space Laser Business Model.

Source record↗
NASA NTRS1978

Applications Technology Satellite program

The Applications Technology Satellite (ATS) program has involved geosynchronous spacecraft technology made possible by the increased capability of the Atlas-Agena launch vehicle. The ATS-1-5 program developed spin stabilized and gravity gradient stabilized spacecraft for geosynchronous orbit, earth-oriented antennae for increased antenna gain, earth-scanning meteorological experiments for continuous weather monitoring, and made possible satellite communications to mobile terminals. The ATS-6 program developed a space-deployed, high-gain antenna for color television broadcast to low-cost ground terminals and precise spacecraft attitude control for pointing, slewing, and tracking applications. All of the ATS program objectives were successfully met, except for the gravity gradient experiments. ATS-1, -3, -5, and -6 are in orbit and operational.

Mcceney, P. J.↗
NASA NTRS1984

Quaternions for Galileo scan platform control

The application of quaternions for the articulation control of the Galileo scan platform is presented in this paper. The purpose of selecting quaternions is to minimize onboard computation time and program size. Attention has been focused on performing inertial pointing while the spacecraft is in a dual spin configuration. Target quaternion and relative target quaternion are introduced and used to specify the target position of the scan platform for point-to-point absolute slews and mosaic relative slews, respectively. The pointing error of the platform is represented by an error quaternion which is converted into gimbal angular errors defining the attitude change. For path control, a moving target quaternion is generated; the corresponding tracking error quaternion and the related spacecraft motion compensation capability are also addressed. A sample slew case is used to demonstrate the implementation of these concepts.

Breckenridge, W. G.↗
NASA NTRS2006

A Tether-Based Variable-Gravity Research Facility Concept

The recent announcement of a return to the Moon and a mission to Mars has made the question of human response to lower levels of gravity more important. Recent advances in tether technology spurred by NASA s research in MXER tethers has led to a re-examination of the concept of a variable-gravity research facility (xGRF) for human research in low Earth orbit. Breakthroughs in simplified inertial tracking have made it possible to consider eliminating the despun section of previous designs. This, in turn, improves the prospect of a facility based entirely around a tether, with the human module on one end and a countermass on the other. With such a configuration, propellantless spinup and spindown is also possible based on the conservation of angular momentum from a gravity-gradient configuration to a spinning configuration. This not only saves large amounts of propellant but vastly simplifies crew and consumable resupply operations, since these can now be done in a microgravity configuration. The importance of the science to be obtained and the performance improvements in this new design argue strongly for further investigation.

Sorensen, Kirk↗
NASA NTRS2012

Gravity Field and Internal Structure of Mercury from MESSENGER

Radio tracking of the MESSENGER spacecraft has provided a model of Mercury's gravity field. In the northern hemisphere, several large gravity anomalies, including candidate mass concentrations (mascons), exceed 100 milli-Galileos (mgal). Mercury's northern hemisphere crust is thicker at low latitudes and thinner in the polar region and shows evidence for thinning beneath some impact basins. The low-degree gravity field, combined with planetary spin parameters, yields the moment of inertia C/M(R(exp 2) = 0.353 +/- 0.017, where M and R are Mercury's mass and radius, and a ratio of the moment of inertia of Mercury's solid outer shell to that of the planet of C(sub m)/C = 0.452 +/- 0.035. A model for Mercury s radial density distribution consistent with these results includes a solid silicate crust and mantle overlying a solid iron-sulfide layer and an iron-rich liquid outer core and perhaps a solid inner core.

Smith, David E.↗
NASA NTRS2012

Gravity Field and Internal Structure of Mercury From MESSENGER

Radio tracking of the MESSENGER spacecraft has provided a model of Mercury’s gravity field. In the northern hemisphere, several large gravity anomalies, including candidate mass concentrations (mascons), exceed 100 milli-Galileos (mgal). Mercury’s northern hemisphere crust is thicker at low latitudes and thinner in the polar region and shows evidence for thinning beneath some impact basins. The low-degree gravity field, combined with planetary spin parameters, yields the moment of inertia C/MR(exp 2) = 0.353 ± 0.017, where M and R are Mercury’s mass and radius, and a ratio of the moment of inertia of Mercury’s solid outer shell to that of the planet of C(sub m)/C = 0.452 ± 0.035. A model for Mercury’s radial density distribution consistent with these results includes a solid silicate crust and mantle overlying a solid iron-sulfide layer and an iron-rich liquid outer core and perhaps a solid inner core.

David E Smith↗
NASA NTRS1976

Advanced atmospheric sounder and imaging radiometer /AASIR/ for STORMSAT

The principal mission of the three-axis stabilized STORMSAT spacecraft is to provide the necessary meteorological data for tracking, studying the detailed structure, and modeling mesoscale weather phenomena. In the area of mesoscale events, the following meteorological objectives are indicated: high-quality imagery, visible and infrared; wind velocity from cloud tracers (1 m/sec), atmospheric temperature profiles (1 K), and atmospheric humidity sounding. These objectives are reflected in the functional characteristics of the AASIR, which is a second generation meteorological sensor based on the Visible Infrared Spin-Scan Radiometer (VISSR) and the Atmospheric Sounder (VAS). The AASIR design and interface constraints with the STORMSAT spacecraft is discussed.

Chase, S. C.↗
NASA NTRS1983

Radio metric orbit determination for the Giotto mission to Comet Halley

An international fleet of five spacecraft will fly past Comet Halley as it travels through the inner solar system in early 1986. This paper discusses orbit determination problems associated with the Giotto spacecraft, sponsored by the European Space Agency. The large number of spin axis precession maneuvers required to maintain the desired spacecraft attitude creates a new kind of radio metric orbit determination problem for this mission. This paper investigates the accuracy with which the Giotto spacecraft orbit can be determined relative to the earth or the sun, and establishes the sensitivity of this accuracy to the selection of the parameters to be estimated, the form of estimator used, the number of tracking stations employed, the length of the data arc, the selection of data types processed, and the levels of various error sources.

Wood, L. J.↗
DOE OSTI2026

Rapid RASER MRI

Conventional Magnetic Resonance Imaging (MRI) relies on high-power Radio-Frequency (RF) pulses to excite nuclear spins and in turn generate NMR signals. These pulses require large high-power RF-amplifiers and cause heat deposition in the tissue, which must be minimized for safety, presenting a growing problem when moving toward ever-higher field MRI. An alternative to RF-pulse excitation is self-excitation of nuclear spins using Radiofrequency Amplification by Stimulated Emission of Radiation (RASER), where the nuclear spins undergo spontaneous transition, without RF excitation, from an over-populated state to a ground state. Here, the feasibility of recording rapid proton RASER MRI images of pyrazine at low concentration (120 mM) with large matrix (128x128 pixels) in as little as 78 ms is demonstrated at 500 MHz (11.7 T). We also recorded a time-series of images using a single bolus hyperpolarized pyrazine highlighting the feasibility of dynamic tracking. Here, the demonstrated approach allows recording MRI scans without transmit-receive electronics of the MRI scanner, which is highly desirable for portable MRI as well as the emerging field of hyperpolarized MRI using, e.g., HP protons, 129 Xe gas or HP 13 C labeled biomolecules as molecular tracers and imaging agents.

MRI↗
DOE OSTI2021

Towards cubic symmetry for Ir 4 + : Structure and magnetism of the antifluorite K 2 IrBr 6

Here, crystal structure, electronic state of Ir 4 + , and magnetic properties of the antifluorite compound K 2 IrBr 6 are studied using high-resolution synchrotron x-ray diffraction, resonant inelastic x-ray scattering (RIXS), thermodynamic and transport measurements, and ab initio calculations. The crystal symmetry is reduced from cubic at room temperature to tetragonal below 170 K and eventually to monoclinic below 122 K. These changes are tracked by the evolution of the noncubic crystal-field splitting Δ measured by RIXS. Nonmonotonic changes in Δ are ascribed to the competing effects of the tilt, rotation, and deformation of the IrBr 6 octahedra as well as tetragonal strain on the electronic levels of Ir 4 + . The Néel temperature of T N = 11.9 K exceeds that of the isostructural K 2 IrCl 6 , and the magnitude of frustration on the fcc spin lattice decreases. We argue that the replacement of Cl by Br weakens electronic correlations and enhances magnetic couplings.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗