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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 919 records · Page 51

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NASA NTRS1992

Final results of an experiment in operational forecasting of sea breeze thunderstorms using a mesoscale numerical model

Sea breeze thunderstorms during quiescent synoptic conductions account for 40 percent of Florida rainfall, and are the dominant feature of April-October weather at the Kennedy Space Center (KSC). An effort is presently made to assess the feasibility of a mesoscale numerical model in improving the point-specific thunderstorm forecasting accuracy at the KSC, in the 2-12 hour time frame. Attention is given to the Applied Regional Atmospheric Modeling System.

Lyons, Walter A.↗

NASA NTRS2000

Error Control Coding Techniques for Space and Satellite Communications

This paper presents a concatenated turbo coding system in which a Reed-Solomom outer code is concatenated with a binary turbo inner code. In the proposed system, the outer code decoder and the inner turbo code decoder interact to achieve both good bit error and frame error performances. The outer code decoder helps the inner turbo code decoder to terminate its decoding iteration while the inner turbo code decoder provides soft-output information to the outer code decoder to carry out a reliability-based soft-decision decoding. In the case that the outer code decoding fails, the outer code decoder instructs the inner code decoder to continue its decoding iterations until the outer code decoding is successful or a preset maximum number of decoding iterations is reached. This interaction between outer and inner code decoders reduces decoding delay. Also presented in the paper are an effective criterion for stopping the iteration process of the inner code decoder and a new reliability-based decoding algorithm for nonbinary codes.

Lin, Shu↗

NASA NTRS2009

Video-Game-Like Engine for Depicting Spacecraft Trajectories

GoView is a video-game-like software engine, written in the C and C++ computing languages, that enables real-time, three-dimensional (3D)-appearing visual representation of spacecraft and trajectories (1) from any perspective; (2) at any spatial scale from spacecraft to Solar-system dimensions; (3) in user-selectable time scales; (4) in the past, present, and/or future; (5) with varying speeds; and (6) forward or backward in time. GoView constructs an interactive 3D world by use of spacecraft-mission data from pre-existing engineering software tools. GoView can also be used to produce distributable application programs for depicting NASA orbital missions on personal computers running the Windows XP, Mac OsX, and Linux operating systems. GoView enables seamless rendering of Cartesian coordinate spaces with programmable graphics hardware, whereas prior programs for depicting spacecraft trajectories variously require non-Cartesian coordinates and/or are not compatible with programmable hardware. GoView incorporates an algorithm for nonlinear interpolation between arbitrary reference frames, whereas the prior programs are restricted to special classes of inertial and non-inertial reference frames. Finally, whereas the prior programs present complex user interfaces requiring hours of training, the GoView interface provides guidance, enabling use without any training.

Upchurch, Paul R.↗

NASA NTRS2013

HESTIA Commodities Exchange Pallet and Sounding Rocket Test Stand

During my Spring 2016 internship, my two major contributions were the design of the Commodities Exchange Pallet and the design of a test stand for a 100 pounds-thrust sounding rocket. The Commodities Exchange Pallet is a prototype developed for the Human Exploration Spacecraft Testbed for Integration and Advancement (HESTIA) program. Under the HESTIA initiative the Commodities Exchange Pallet was developed as a method for demonstrating multi-system integration thru the transportation of In-Situ Resource Utilization produced oxygen and water to a human habitat. Ultimately, this prototype's performance will allow for future evaluation of integration, which may lead to the development of a flight capable pallet for future deep-space exploration missions. For HESTIA, my main task was to design the Commodities Exchange Pallet system to be used for completing an integration demonstration. Under the guidance of my mentor, I designed, both, the structural frame and fluid delivery system for the commodities pallet. The fluid delivery system includes a liquid-oxygen to gaseous-oxygen system, a water delivery system, and a carbon-dioxide compressors system. The structural frame is designed to meet safety and transportation requirements, as well as the ability to interface with the ER division's Portable Utility Pallet. The commodities pallet structure also includes independent instrumentation oxygen/water panels for operation and system monitoring. My major accomplishments for the commodities exchange pallet were the completion of the fluid delivery systems and the structural frame designs. In addition, parts selection was completed in order to expedite construction of the prototype, scheduled to begin in May of 2016. Once the commodities pallet is assembled and tested it is expected to complete a fully integrated transfer demonstration with the ISRU unit and the Environmental Control and Life Support System test chamber in September of 2016. In addition to the development of the Commodities Exchange Pallet, I also assisted in preparation for testing the upper stage of a sounding rocket developed as a Center Innovation Fund project. The main objective of this project is to demonstrate the integration between a propulsion system and a solid oxide fuel cell (SOFC). The upper stage and SOFC are scheduled to complete an integrated test in August of 2016. As part of preparation for scheduled testing, I was responsible for designing the upper stage's test stand/support structure and main engine plume deflector to be used during hot-fire testing (fig. 3). The structural components of the test stand need to meet safety requirements for operation of the propulsion system, which consist of a 100 pounds-thrust main engine and two 15 pounds-thrust reaction control thrusters. My main accomplishment for this project was the completion of the design and the parts selection for construction of the structure, scheduled to begin late April of 2016.

Chaparro, Javier↗

NASA NTRS2010

Pixel-Level Calibration in the Kepler Science Operations Center Pipeline

We present an overview of the pixel-level calibration of flight data from the Kepler Mission performed within the Kepler Science Operations Center Science Processing Pipeline. This article describes the calibration (CAL) module, which operates on original spacecraft data to remove instrument effects and other artifacts that pollute the data. Traditional CCD data reduction is performed (removal of instrument/detector effects such as bias and dark current), in addition to pixel-level calibration (correcting for cosmic rays and variations in pixel sensitivity), Kepler-specific corrections (removing smear signals which result from the lack of a shutter on the photometer and correcting for distortions induced by the readout electronics), and additional operations that are needed due to the complexity and large volume of flight data. CAL operates on long (~30 min) and short (~1 min) sampled data, as well as full-frame images, and produces calibrated pixel flux time series, uncertainties, and other metrics that are used in subsequent Pipeline modules. The raw and calibrated data are also archived in the Multi-mission Archive at Space Telescope at the Space Telescope Science Institute for use by the astronomical community.

Calibration↗

NASA NTRS2002

The Solar-Sail Launched Interstellar Probe: Pre-Perihelion Trajectories and Application of Holography

Design of missions beyond our solar system presents many challenges. Here, we consider certain aspects of the solar-sail launched interstellar probe (ISP), a spacecraft slated for launch in the 2010 time period that is planned to reach the heliopause, at 200 Astronomical Units (AU) from the Sun after a flight of about 20-years duration. The baseline mission under consideration by NASA / JPL has a sail radius of 200 m, a science payload of 25 kg, a spacecraft areal mass thickness of about two grams per square meter and is accelerated out of the solar system at about 14 AU per year after performing a perihelion pass of about 0.25 AU. In current plans, the sail is to be dropped near Jupiter's orbit (5.2 AU from the Sun) on the outbound trajectory leg. One aspect of this study is application of a realistic model of sail thermo-optics to sail kinematics that includes diffuse / specular reflectance and sail roughness. The effects of solar-wind degradation of sail material, based on recent measurements at the NASA MSFC (Marshall Space Flight Center) Space Environment Facility were incorporated in the kinematical model. After setting initial and final conditions for the spacecraft, trajectory was optimized using the provision of variable sail aspect angle. The second phase of the study included consideration of rainbow holography as a medium for a message plaque that would be carried aboard the ISP in the spirit of the message plaques aboard Pioneer 10 /11 and Voyager 1 /2. A prototype holographic message plaque was designed and created by artist C. Bangs with the assistance of Ana Maria Nicholson and Dan Schweitzer of the Center for Holographic Arts in Long Island City, NY. The piece was framed by Simon Liu Inc. of Brooklyn, NY. Concurrent to the creation of the prototype message plaque, we explored the potential of this medium to transmit large amounts of visual information to any extraterrestrial civilization that might detect and intercept ISP. It was also necessary to investigate possible degradation of holograms by the space environment. We developed a new way of characterizing the optical quality of holograms.

Gregory L. Matloff↗

DOE OSTI2025

Analysis of Two Models for the Angular Structure of the Outflows Producing the Swift/XRT “Larger-angle Emission” of Gamma-Ray Bursts

The quasi-instantaneous emission from a relativistic surface endowed with a Lorentz factor that decreases away from the outflow symmetry axis can naturally explain the three phases observed by Swift X-Ray Telescope (XRT) in gamma-ray bursts (GRBs) and their afterglows (GRB tail, afterglow plateau, and postplateau) based only on the angular change of the relativistic Doppler boost across the outflow surface. We develop further the analytical formalism of the “larger-angle emission” model for the case of “n-exponential” outflows (where the Lorentz factor Γ dependence of the angular location θ is Γ ~ exp{-(θ/θ c ) n }), and compare its ability to account for the X-ray emission of XRT afterglows relative to that of “power-law” outflows (Γ ∼ θ −g ). Power-law outflows yield longer afterglow plateaus, followed by slower postplateau flux decays than n-exponential outflows, features which may be used in identifying which type of angular structure is at work in a given afterglow. Identifying the Γ(θ) angular structure that accommodates XRT light curves is slightly complicated by the fact that the afterglow X-ray light curve is also determined by how two characteristics of the comoving-frame emission spectrum (peak energy $E'_p$ and peak intensity $i'_p$) change with the angular location or, equivalently, with the Lorentz factor. Here, we assume power-law Γ dependences of those spectral characteristics and find that, unlike power-law outflows, n-exponential outflows cannot account for plateaus with a temporal dynamical range larger than 100 (2 dex in logarithmic space). To capture all the information contained in XRT afterglow measurements (0.3–10 keV unabsorbed flux and effective spectral slope), we calculate 0.3 and 10 keV light curves using a broken-power-law emission spectrum of peak energy and low- and high-energy slopes that are derived from the effective slope measured by XRT. This economical peak energy determination is found to be consistent with the results of more expensive spectral fits. The angular distributions of the Lorentz factor, comoving frame peak energy, and peak intensity (Γ(θ), $E'_p$(θ), $i'_p$(θ)) constrain the (yet-to-be determined) convolution of various features of the production of relativistic jets by solar-mass black holes and of their propagation through the progenitor/circumburst medium, while the $E'_p$(Γ) and $i'_p$(Γ) dependences may constrain the GRB dissipation mechanism and the GRB emission process.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS2012

Observing System Simulations for the NASA ASCENDS Lidar CO2 Mission Concept: Substantiating Science Measurement Requirements

The NASA ASCENDS mission (Active Sensing of Carbon Emissions, Nights, Days, and Seasons) is envisioned as the next generation of dedicated, space-based CO2 observing systems, currently planned for launch in about the year 2022. Recommended by the US National Academy of Sciences Decadal Survey, active (lidar) sensing of CO2 from space has several potentially significant advantages, in comparison to current and planned passive CO2 instruments, that promise to advance CO2 measurement capability and carbon cycle understanding into the next decade. Assessment and testing of possible lidar instrument technologies indicates that such sensors are more than feasible, however, the measurement precision and accuracy requirements remain at unprecedented levels of stringency. It is, therefore, important to quantitatively and consistently evaluate the measurement capabilities and requirements for the prospective active system in the context of advancing our knowledge of carbon flux distributions and their dependence on underlying physical processes. This amounts to establishing minimum requirements for precision, relative accuracy, spatial/temporal coverage and resolution, vertical information content, interferences, and possibly the tradeoffs among these parameters, while at the same time framing a mission that can be implemented within a constrained budget. Here, we present results of observing system simulation studies, commissioned by the ASCENDS Science Requirements Definition Team, for a range of possible mission implementation options that are intended to substantiate science measurement requirements for a laser-based CO2 space instrument.

Kawa, Stephan R.↗

DOE OSTI2026

Optimal CO 2 storage management considering safety constraints in multi-stakeholder multi-site GCS projects: A Markov game perspective

Geological carbon storage (GCS) projects could involve a diverse array of stakeholders or players from public, private, and regulatory sectors, each with different objectives and responsibilities. Given the complexity, scale, and long-term nature of GCS operations, determining whether individual stakeholders can independently optimize their interests — or whether collaborative coalition agreements are needed — remains a central question for effective GCS project planning and management. To access large, high-quality storage resources, future GCS deployment may increasingly occur in geologically connected sites, where shared geological features such as pressure space and reservoir pore capacity can lead to competitive behavior among stakeholders. In this work, we propose a paradigm based on Markov games to quantitatively investigate how different coalition structures affect the goals of stakeholders. We frame this multi-stakeholder multi-site problem as a multi-agent reinforcement learning problem with safety constraints. Our approach enables agents to learn optimal strategies while complying with safety regulations. We present an example where multiple operators are injecting CO 2 into their respective project areas in a geologically connected basin. To address the high computational cost of repeated simulations of high fidelity models, a previously developed surrogate model based on the Embed-to-Control (E2C) framework is employed. Our results demonstrate the effectiveness of the proposed framework in addressing optimal management of CO 2 storage when multiple stakeholders with different objectives and goals are involved.

58 GEOSCIENCES↗

DOE OSTI2018

Search for dark matter in events with a hadronically decaying vector boson and missing transverse momentum in p p collisions at s = 13 TeV with the ATLAS detector

CERN-LHC. This entry relates to the search for Dark Matter (DM) in association with a hadronically decaying vector boson with 36.1 fb-1 of pp collision data at a center-of-mass energy of sqrt(s) = 13 TeV recorded by the ATLAS detector at the LHC. In adition to hadronic decays of W and Z bosons, decays of the non-Standard-Model vector boson Z' of unknown masses are also considered for the first time (mono-Z'). The results are interpreted in terms of limits on the invisible Higgs boson decays into Dark Matter particles, constraints on the patamter space of the simplified vector-mediator model and generic upper limits on the visible detector-level cross sections for the W/Z+DM production. The results of the mono-Z' are shown in the frame of two simplified-model scenarios involving the DM production in assocaiation with the Z' boson. These are the dark Higgs model and the dark fermion model, each with a light and heavy dark sector scenario.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

NASA NTRS1981

Torque-wrench extension

Torque-wrench extension makes it easy to install and remove fasteners that are beyond reach of typical wrenches or are located in narrow spaces that prevent full travel of wrench handle. At same time, tool reads applied torque accurately. Wrench drive system, for torques up to 125 inch-pounds, uses 2 standard drive-socket extensions in aluminum frame. Extensions are connected to bevel gear that turns another bevel gear. Gears produce 1:1 turn ratio through 90 degree translation of axis of rotation. Output bevel has short extension that is used to attach 1/4-inch drive socket.

Peterson, D. H.↗

NASA NTRS1980

Solar heating system at Quitman County Bank, Marks, Mississippi

Information on the Solar Energy Heating System installed in a single story wood frame, cedar exterior, sloped roof building is presented. The system has on-site temperature and power measurements readouts. The 468 square feet of Solaron air flat plate collectors provide for 2,000 square feet of space heating, an estimated 60 percent of the heating load. Solar heated air is distributed to the 235 cubic foot rock storage box or to the load (space heating) by a 960 cubic feet per minute air handler unit. A 7.5 ton Carrier air-to-air heat pump with 15 kilowatts of electric booster strips serve as a back-up (auxiliary) to the solar system. Motorized dampers control the direction of airflow and back draft dampers prevent thermal siphoning of conditioned air.

Source record↗

NASA NTRS1990

Automation of Space Station module power management and distribution system

Viewgraphs on automation of space station module (SSM) power management and distribution (PMAD) system are presented. Topics covered include: reasons for power system automation; SSM/PMAD approach to automation; SSM/PMAD test bed; SSM/PMAD topology; functional partitioning; SSM/PMAD control; rack level autonomy; FRAMES AI system; and future technology needs for power system automation.

Bechtel, Robert↗

NASA NTRS2010

Far-Ultraviolet Number Counts of Field Galaxies

The Number counts of far-ultraviolet (FUV) galaxies as a function of magnitude provide a direct statistical measure of the density and evolution of star-forming galaxies. We report on the results of measurements of the rest-frame FUV number counts computed from data of several fields including the Hubble Ultra Deep Field, the Hubble Deep Field North, and the GOODS-North and -South fields. These data were obtained from the Hubble Space Telescope Solar Blind Channel of the Advance Camera for Surveys. The number counts cover an AB magnitude range from 20-29 magnitudes, covering a total area of 15.9 arcmin'. We show that the number counts are lower than those in previous studies using smaller areas. The differences in the counts are likely the result of cosmic variance; our new data cover more area and more lines of sight than the previous studies. The slope of our number counts connects well with local FUV counts and they show good agreement with recent semi-analytical models based on dark matter "merger trees".

Voyer, Elysse N.↗

NASA NTRS2015

Earth Science With the Stratospheric Aerosol and Gas Experiment III (SAGE III) on the International Space Station

The Stratospheric Aerosol and Gas Experiment (SAGE) III is the fourth generation of solar occultation instruments operated by NASA, the first coming under a different acronym, to investigate the Earth's upper atmosphere. Three flight-ready SAGE III instruments were built by Ball Aerospace in the late 1990s, with one launched aboard the former Russian Aviation and Space Agency (now known as Roskosmos) Meteor-3M platform on 10 December 2001 (continuing until the platform lost power in 2006). Another of the original instruments was manifested for the ISS in the 2004 time frame, but was delayed because of budgetary considerations. Fortunately, that SAGE III/ISS mission was restarted in 2009 with a major focus upon filling an anticipated gap in ozone and aerosol observation in the second half of this decade. Here we discuss the mission architecture, its implementation, and data that will be produced by SAGE III/ISS, including their expected accuracy and coverage. The 52-degree inclined orbit of the ISS is well-suited for solar occultation and provides near-global observations on a monthly basis with excellent coverage of low and mid-latitudes. This is similar to that of the SAGE II mission (1985-2005), whose data set has served the international atmospheric science community as a standard for stratospheric ozone and aerosol measurements. The nominal science products include vertical profiles of trace gases, such as ozone, nitrogen dioxide and water vapor, along with multi-wavelength aerosol extinction. Though in the visible portion of the spectrum the brightness of the Sun is one million times that of the full Moon, the SAGE III instrument is designed to cover this large dynamic range and also perform lunar occultations on a routine basis to augment the solar products. The standard lunar products were demonstrated during the SAGE III/M3M mission and include ozone, nitrogen dioxide & nitrogen trioxide. The operational flexibility of the SAGE III spectrometer accomplishes the main goal of producing ozone and aerosol extinction profiles, while allowing exploration of new possibilities for the occultation technique, such as night-time aerosol extinction profiles or other trace gases not measured by SAGE in the past.

Zawodny, Joe↗

NASA NTRSDate not supplied

A Discussion of Time Management Concepts and Time Constraint Equations for Multi-Rate Federation Executions

The High Level Architecture (HLA) is a simulation interoperability standard developed by the Simulation Interoperability Standards Organization (SISO) and published as the international standard IEEE 1516-2010 by the Institute for Electrical and Electronics Engineers (IEEE). HLA is a widely used standard for the development and execution of collaborative distributed simulations. HLA provides a number of Management Services to simulation developers: Federation, Declaration, Object, Ownership, Data Distribution, and Time. Of those services, Time Management Services is probably one of the least understood and least used. However, Time Management Services are critical to technical simulations like those created for space systems using the Space Reference Federation Object Model (SpaceFOM). Time Management can be used to insure data coherence and execution repeatability in distributed simulations. When combined with real time execution policies, Time Management is being used to support real time execution of mixed software and hardware in the loop integration, verification, and validation simulations for active space systems development. This paper starts by providing an overview of the HLA Time Management Services. This provides the background to discuss the challenges associated with Time Management and its use, starting with simple common rate frame scheduled simulations, then simple multi-rate simulations, and ending with complex mixed rate simulations. The authors then formulate the significant time constraint relationships between identified frame scheduling parameters. The intent of the paper is to provide a concise discussion of how to use Time Management in both simple cases and in more complex mixed frame rate federation executions.

Simulation Interoperability↗

NASA NTRSDate not supplied

A Discussion of Time Management Concepts and Time Constraint Equations for Multi-Rate Federation Executions

Simulation Interoperability↗

NASA NTRS2006

Variable-Tension-Cord Suspension/Vibration-Isolation System

A system for mechanical suspension and vibration isolation of a machine or instrument is based on the use of Kevlar (or equivalent aromatic polyamide) cord held in variable tension between the machine or instrument and a surrounding frame. The basic concept of such a tensioned-cord suspension system (including one in which the cords are made of aromatic polyamide fibers) is not new by itself; what is new here is the additional provision for adjusting the tension during operation to optimize vibration- isolation properties. In the original application for which this system was conceived, the objective is to suspend a reciprocating cryocooler aboard a space shuttle and to prevent both (1) transmission of launch vibrations to the cryocooler and (2) transmission of vibrations from the cryocooler to samples in a chamber cooled by the cryocooler. The basic mechanical principle of this system can also be expected to be applicable to a variety of other systems in which there are requirements for cord suspension and vibration isolation. The reciprocating cryocooler of the original application is a generally axisymmetric object, and the surrounding frame is a generally axisymmetric object with windows (see figure). Two cords are threaded into a spoke-like pattern between attachment rings on the cryocooler, holes in the cage, and cord-tension- adjusting assemblies. Initially, the cord tensions are adjusted to at least the level necessary to suspend the cryocooler against gravitation. Accelerometers for measuring vibrations are mounted (1) on the cold tip of the cryocooler and (2) adjacent to the cage, on a structure that supports the cage. During operation, a technician observes the accelerometer outputs on an oscilloscope while manually adjusting the cord tensions in an effort to minimize the amount of vibration transmitted to and/or from the cryocooler. A contemplated future version of the system would include a microprocessor-based control subsystem that would include cord-tension actuators. This control subsystem would continually adjust the cord tension in response to accelerometer feedback to optimize vibration-isolation properties as required for various operating conditions. The control system could also adjust cord tensions (including setting the two cords to different tensions) to suppress resonances. Other future enhancements could include optimizing the cord material, thickness, and braid; optimizing the spoke patterns; and adding longitudinal cords for applications in which longitudinal stiffness and vibration suppression are required.

Villemarette, Mark L.↗