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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 685 records · Page 38

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NASA NTRS1946

Analysis of cooling limitations and effect of engine-cooling improvements on level-flight cruising performance of four-engine heavy bomber

The NACA has developed means, including an injection impeller and ducted head baffles, to improve the cooling characteristics of the 3350-cubic-inch-displacement radial engines installed in a four-engine heavy bomber. The improvements afforded proper cooling of the rear-row exhaust-valve seats for a wide range of cowl-flap angles, mixture strengths, and airplane speeds. The results of flight tests with this airplane are used as a basis for a study to determine the manner and the extent to which the airplane performance was limited by engine cooling. By means of this analysis for both the standard airplane and the airplane with engine-cooling modifications, comparison of the specific range at particular conditions and comparison of the cruising-performance limitations was made.

Marble, Frank E↗

NASA NTRS1993

Computer program for thermal and transport properties of parahydrogen from 20 to 10,000 K

A computer program was recently developed to provide thermal and transport properties for parahydrogen across a wide temperature and pressure range. The program, NBS+/-pH2, matches the most recent parahydrogen property data from the National Bureau of Standards up to 3000 K and property data from the NASA Lewis Research Center's Chemical Equilibrium Computer Program up to 10,000 K. The pressure range of NBS+/-pH2 is from 1 x 10(exp 4) to 1.6 x 10(exp 7) Pa. The program was developed to meet the need for accurate parahydrogen properties from liquid to dissociated conditions as required by propulsion simulation programs being developed under the Space Exploration Initiative. NBS+/-pH2 is a machine-independent, standard Fortran 77 program which provides density, thermal conductivity, viscosity, Prandtl number, entropy, specific heats, and speed of sound given pressure and either temperature or enthalpy. This program is described and a comparison to programs previously available is provided.

Walton, James T.↗

NASA NTRS1994

Magnetocentrifugally driven flows from young stars and disks. 2: Formulation of the dynamical problem

We formulate the dynamical problem of a cool wind centrifugally driven from the magnetic interface of a young star and an adjoining Keplerian disk. We examine the situation for mildly accreting T Tauri stars that rotate slowly as well as rapidly accreting protostars that rotate near break-up. In both cases a wind can be driven from a small X-region just outside the stellar magnetopause, where the field lines assume an open geometry and are rooted to material that rotates at an angular speed equal both to the local Keplerian value and to the stellar angular speed. Assuming axial symmetry for the ideal magnetohydrodynamic flow, which requires us to postpone asking how the (lightly ionized) gas is loaded onto field lines, we can formally integrate all the governing equations analytically except for a partial equation that describes how streamlines spread in the meridional plane. Apart from the difficulty of dealing with PDEs of mixed type, finding the functional forms of the conserved quantities along streamlines - the ratio beta of magnetic field to mass flux, the specific energy H of the fluid in the rotating frame, and the total specific angular momentum J carried in the matter and the field - constitutes a standard difficulty in this kind of (Grad-Shafranov) formalism. Fortunately, because the ratio of the thermal speed of the mass-loss regions to the Keplerian speed of rotation of the interface constitutes a small parameter epsilon, we can attack the overall problem by the method of matched asymptotic expansions. This procedure leads to a natural and systematic technique for obtaining the relevant functional dependences of beta, H, and J. Moreover, we are able to solve analytically for the properties of the flow emergent from the small transsonic region driven by gas pressure without having to specify the detailed form of any of the conserved functions, beta, H, and J. This analytical solution provides inner boundary conditions for the numerical computation in a companion paper by Najita & Shu of the larger region where the main acceleration to terminal speeds occurs.

Shu, Frank H.↗

NASA NTRS2000

Evaluation of DVD-R for Archival Applications

For more than a decade, CD-ROM and CD-R have provided an unprecedented level of reliability, low cost and cross-platform compatibility to support federal data archiving and distribution efforts. However, it should be remembered that years of effort were required to achieve the standardization that has supported the growth of the CD industry. Incompatibilities in the interpretation of the ISO-9660 standard on different operating systems had to be dealt with, and the imprecise specifications in the Orange Book Part n and Part Hi led to incompatibilities between CD-R media and CD-R recorders. Some of these issues were presented by the authors at Optical Data Storage '95. The major current problem with the use of CD technology is the growing volume of digital data that needs to be stored. CD-ROM collections of hundreds of volumes and CD-R collections of several thousand volumes are becoming almost too cumbersome to be useful. The emergence of Digital Video Disks Recorder (DVD-R) technology promises to reduce the number of discs required for archive applications by a factor of seven while providing improved reliability. It is important to identify problem areas for DVD-R media and provide guidelines to manufacturers, file system developers and users in order to provide reliable data storage and interchange. The Data Distribution Laboratory (DDL) at NASA's Jet Propulsion Laboratory began its evaluation of DVD-R technology in early 1998. The initial plan was to obtain a DVD-Recorder for preliminary testing, deploy reader hardware to user sites for compatibility testing, evaluate the quality and longevity of DVD-R media and develop proof-of-concept archive collections to test the reliability and usability of DVD-R media and jukebox hardware.

Martin, Michael D.↗

NASA NTRS2002

Reference and Standard Atmosphere Models

This paper describes the development of standard and reference atmosphere models along with the history of their origin and use since the mid 19th century. The first "Standard Atmospheres" were established by international agreement in the 1920's. Later some countries, notably the United States, also developed and published "Standard Atmospheres". The term "Reference Atmospheres" is used to identify atmosphere models for specific geographical locations. Range Reference Atmosphere Models developed first during the 1960's are examples of these descriptions of the atmosphere. This paper discusses the various models, scopes, applications and limitations relative to use in aerospace industry activities.

Johnson, Dale L.↗

NASA NTRS2003

Improving the Agency's Software Acquisition Capability

External development of software has oftc n led to unsatisfactory results and great frustration for the assurE 7ce community. Contracts frequently omit critical assuranc 4 processes or the right to oversee software development activitie: At a time when NASA depends more and more on software to in plement critical system functions, combination of three factors ex; cerbate this problem: I ) the ever-increasing trend to acquire rather than develop software in-house, 2) the trend toward performance based contracts, and 3) acquisition vehicles that only state softwar 2 requirements while leaving development standards and assur! ince methodologies up to the contractor. We propose to identify specific methods at d tools that NASA projects can use to mitigate the adverse el ects of the three problems. TWO broad classes of methoddt ~ols will be explored. The first will be those that provide NASA p ojects with insight and oversight into contractors' activities. The st cond will be those that help projects objectively assess, and thus i nprwe, their software acquisition capability. Of particular interest is the Software Engineering Institute's (SEI) Software Acqt isition Capability Maturity Model (SA-CMMO).

Hankinson, Allen↗

NASA NTRS2004

Wireless Communications in Space

In 1992, NASA and the U.S. Department of Defense jointly commissioned the research and development of a technology solution to address the challenges and requirements of communicating with their spacecraft. The project yielded an international consortium composed of representatives from the space science community, industry, and academia. This group of experts developed a broad suite of protocols specifically designed for space-based communications, known today as Space Communications Protocol Standards (SCPS). Having been internationally standardized by the Consultative Committee on Space Data Systems and the International Standards Organization, SCPS is distributed as open source technology by NASA s Jet Propulsion Laboratory (JPL). The protocols are used for every national space mission that takes place today.

Source record↗

NASA NTRS2005

"XMM/RXTE Observations of GX 339-4"

In March 2003, we performed two simultaneous XMM/RXTE observations of the black hole candidate GX 339-4. Our goal is to compare these data to our prior simultaneous RXTE/ASCA observations (Nowak, Wilms & Dove, 2002). These observations were carried out in timing mode, as opposed to burst mode, and are more complex to analyze than we expected. Specifically, the data suffered from a number of telemetry dropouts (in fact, the standard archive processing failed on these data, and more than a year passed from the time of the observations before the data was delivered to us). Furthermore, the core of the EPIC PSF suffers slightly from pileup and gain shifts. We continue to work on this data, however, and anticipate publishing it within the next academic year. Here we highlight our ongoing work and outline our plans for publication.

Nowak, M. A.↗

NASA NTRS1997

Using Non-Linear Statistical Methods with Laboratory Kinetic Data

This paper will demonstrate the usefulness of standard non-linear statistical analysis on ICR and SIFT kinetic data. The specific systems used in the demonstration are the isotopic and change transfer reactions in the system of H2O+/D2O, H30+/D2O, and other permutations.

non-linear analysis kinetic isotopic permutations ↗

NASA NTRS2007

Determination of Scopolamine in Human Saliva Using Solid Phase Extraction and LC/MS/MS

Purpose: Scopolamine is the preferred treatment for motion sickness during space flight because of its quick onset of action, short half-life and favorable side-effect profile. The dose administered depends on the mode of administration and usually ranges between 0.1 and 0.8 mg. Such small doses make it difficult to detect concentrations of scopolamine in biological fluids by using conventional HPLC methods. To measure scopolamine in saliva and thereby to evaluate the pharmacokinetics of scopolamine, we developed an LC/MS/MS method using off-line solid phase extraction. Method: Samples (0.5mL) were loaded onto Waters Oasis HLB co-polymer cartridges (10 mg, 1 mL) and eluted with 0.5 mL methanol without evaporation and reconstitution. HPLC separation of the eluted sample was performed using an Agilent Zorbax SB-CN column (50 x 2.1 mm) at a flow rate of 0.2 mL/min for 4 minutes. The mobile phase for separation was 90:10 (v/v) methanol: ammonium acetate (2 mM) in water, pH 5.0 +/- 0.1. Concentrations of scopolamine were determined using a Micromass Quattro Micro(TM) mass spectrometer with electrospray ionization (ESI). ESI mass spectra were acquired in positive ion mode with multiple reaction monitoring for the determination of scopolamine m/z = 304.2 yields 138.1 and internal standard (IS) hyoscyamine m/z = 290.2 yields 124.1. Results: The method is rapid, reproducible, specific and has the following parameters: scopolamine and the IS are eluted at 1.7 and 3.2 min respectively. The linear range is 50-5000 pg/mL for scopolamine in saliva with correlation coefficients > 0.99 with a CV < 0.5 %. The intra-day and inter-day CVs are < 15 % for quality control samples with concentrations of 75, 300, 750 and 3000 pg/mL of scopolamine in human saliva. Conclusion: Solid phase extraction allows more rapid sample preparation and greater precision than liquid extraction. Furthermore, we increased the sensitivity and specificity by adjusting the LC mobile phase and using an MS/MS detector.

Wang, Zuwei↗

NASA NTRS2009

Adjoint-Based Diagnostics in Atmospheric Data Assimilation

With the adjoint of a data assimilation system, the impact of any or all assimilated observations on measures of forecast or analysis skill can be estimated accurately and efficiently. The approach is especially well-suited for assessing the impact of hyper-spectral satellite instruments on numerical weather forecasts because it easily allows aggregation of results in terms of individual data types, channels or locations, all computed simultaneously based on a single pass of the Adjoint- system. This talk 'provides a general overview of the use of Adjoint-based diagnostic tools in data assimilation. We will focus on the theoretical basis and practical implementation of these tools, as well as their application to specific problems. Adjoint-based Impact calculations will be compared with results from standard observing system experiments (OSEs) and their application to related problems, such as the calibration of Observing System Simulation Experiments (OSSEs) will be discussed.

Gelaro, Ronald↗

NASA NTRS2011

NASA Presentation to TechAmerica G12 Committee

This slide presentation reviews some of the actions that NASA is taking to address the issue of counterfeit electronic parts. While the emphasis is on electronic parts, the vision is broad enough to include materials and software. The effort includes coordination with other agencies, to identify and with the Government-Industry Data Exchange Program (GIDEP). An interim GIDEP Policy for suspected counterfeits was instituted. NASA's recommendation to the policy was for identification of the supplier and suggests allowing access to that information by government only. The issues with the General MIL specification, the testing requirements for radiation issues, the continuing development of Class Y standards for electronic equipment, status of package case isolation tests needed for 750 and 883,enhancement of 750 Internal Visual Inspection are reviewed. Further issues with consistent ESD control conditions across commodities, test methods, humidity limits, etc are briefly reviewed. The cost benefit analysis of film versus Real time radiography are also reviewed.

LaBel, Kenneth A.↗

NASA NTRS2011

Aeronautical Mobile Airport Communications System (AeroMACS)

To help increase the capacity and efficiency of the nation s airports, a secure wideband wireless communications system is proposed for use on the airport surface. This paper provides an overview of the research and development process for the Aeronautical Mobile Airport Communications System (AeroMACS). AeroMACS is based on a specific commercial profile of the Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard known as Wireless Worldwide Interoperability for Microwave Access or WiMAX (WiMax Forum). The paper includes background on the need for global interoperability in air/ground data communications, describes potential AeroMACS applications, addresses allocated frequency spectrum constraints, summarizes the international standardization process, and provides findings and recommendations from the world s first AeroMACS prototype implemented in Cleveland, Ohio, USA.

Budinger, James M.↗

NASA NTRS2015

Design, Fabrication, and Testing of a Composite Rack Prototype in Support of the Deep Space Habitat Program

In support of the Deep Space Habitat project a number of composite rack prototypes were developed, designed, fabricated and tested to various extents ( with the International Standard Payload Rack configuration, or crew quarters, as a baseline). This paper focuses specifically on a composite rack prototype with a direct tie in to Space Station hardware. The outlined prototype is an all composite construction, excluding metallic fasteners, washers, and their associated inserts. The rack utilizes braided carbon composite tubing for the frame with the sidewalls, backwall and flooring sections utilizing aircraft grade composite honeycomb sandwich panels. Novel additively manufactured thermoplastic joints and tube inserts were also developed in support of this effort. Joint and tube insert screening tests were conducted at a preliminary level. The screening tests allowed for modification, and enhancement, of the fabrication and design approaches, which will be outlined. The initial joint tests did not include mechanical fasteners. Adhesives were utilized at the joint to composite tube interfaces, along with mechanical fasteners during final fabrication (thus creating a stronger joint than the adhesive only variant). In general the prototype was focused on a potential in-space assembly approach, or kit-of-parts construction concept, which would not necessarily require the inclusion of an adhesive in the joint regions. However, given the tie in to legacy Station hardware (and potential flight loads with imbedded hardware mass loadings), the rack was built as stiff and strong as possible. Preliminary torque down tests were also conducted to determine the feasibility of mounting the composite honeycomb panels to the composite tubing sections via the additively manufactured tube inserts. Additional fastener torque down tests were also conducted with inserts (helicoils) imbedded within the joints. Lessons learned are also included and discussed.

Smith, Russ↗

NASA NTRS2017

Verification and Validation Process for Progressive Damage and Failure Analysis Methods in the NASA Advanced Composites Consortium

The Advanced Composites Consortium is a US Government/Industry partnership supporting technologies to enable timeline and cost reduction in the development of certified composite aerospace structures. A key component of the consortium's approach is the development and validation of improved progressive damage and failure analysis methods for composite structures. These methods will enable increased use of simulations in design trade studies and detailed design development, and thereby enable more targeted physical test programs to validate designs. To accomplish this goal with confidence, a rigorous verification and validation process was developed. The process was used to evaluate analysis methods and associated implementation requirements to ensure calculation accuracy and to gage predictability for composite failure modes of interest. This paper introduces the verification and validation process developed by the consortium during the Phase I effort of the Advanced Composites Project. Specific structural failure modes of interest are first identified, and a subset of standard composite test articles are proposed to interrogate a progressive damage analysis method's ability to predict each failure mode of interest. Test articles are designed to capture the underlying composite material constitutive response as well as the interaction of failure modes representing typical failure patterns observed in aerospace structures.

Wanthal, Steven↗

NASA NTRS2020

Ensemble Methodologies for Astronaut Cancer Risk Assessment in the face of Large Uncertainties

A new approach to NASA space radiation risk modeling has successfully extended the current NASA probabilistic cancer risk model to an ensemble framework able to consider sub-model parameter uncertainty (e.g. uncertainty in a radiation quality parameter) as well as model-form uncertainty associated with differing theoretical or empirical formalisms (e.g. combined dose-rate and radiation quality effects). Ensemble methodologies are already widely used in weather prediction, modeling of infectious disease outbreaks, and certain terrestrial radiation protection applications to better understand how uncertainty may influence risk decision-making. Applying ensemble methodologies to space radiation risk projections offers the potential to efficiently incorporate emerging research results, allow for the incorporation of future (including international) models, improve uncertainty quantification for underlying sub-models developed against sparse experimental data, and reduce the impact of subjective bias on risk projections. Moreover, risk forecasting across an ensemble of multiple predictive models can provide stakeholders additional information on risk acceptance if current health/medical standards cannot be met or the level of knowledge doesn’t permit a specific risk or exposure limit to be developed for future space exploration missions. In this work, ensemble risk projections implementing multiple sub-models of radiation quality, dose and dose-rate effectiveness factors, excess risk, and latency as ensemble members are presented. Initial consensus methods for ensemble model weights and correlations to account for individual model bias are discussed. In these analyses, the ensemble forecast compares well to results from NASA's current operational cancer risk projection model used to assess permissible exposure limits and permissible mission durations for astronauts. However, a large range of projected risk values are obtained at the upper 95th confidence level where models must extrapolate beyond available biological data sets; closer agreement is seen at the median + one sigma due to the inherent similarities in available models. Future work, including the addition of new models and methods for statistical correlation between predictive members are discussed to define alternate ways of thinking about risk and ‘acceptable’ uncertainty with respect to NASA’s current permissible exposure limits.

space radiation↗

NASA NTRSDate not supplied

Ensemble Cancer Risk Model for Astronaut Risk Assessment

Lisa C Simonsen↗

NASA NTRS2020

Demonstrating Assurance of Model-Based Fault Diagnosis Systems on an Operational Mission

Developers of robotic scientific and commercial spacecraft are trending towards use of onboard autonomous capabilities for responding quickly to dynamic environments and rapidly changing situations. These capabilities need to know the state of the spacecraft’s health. Model-based fault diagnosis (MBFD) is an approach to estimating health by continuously verifying accurate behavior and diagnosing off-nominal behavior. Proper functioning of MBFD depends on 1) the quality of the diagnostic system model that is analyzed and compared to commands and onboard measurements to estimate a system’s health state, and 2) the correct functionality of the diagnosis engine interrogating the model and comparing its analyses to observed system behavior. Our goal is to develop Verification and Validation (V&V) techniques for MBFD to provide future missions sufficient confidence in its functionality and performance to deploy it on the systems they develop. Our work has been focused on infusing the techniques we developed earlier to an operational mission. First, we are constructing diagnostic models of a spacecraft attitude control system and updating our diagnostic engine so they can be demonstrated aboard the Arcsecond Space Telescope Enabling Research in Astrophysics (ASTERIA) mission, an operational spacecraft for which experiments in autonomy are being planned and executed, using the V&V techniques we have previously developed to assure they are both correct and complete. Since it is nearing the end of its life, ASTERIA provides a unique opportunity to demonstrate MBFD since the monitored components are expected to fail. Our demonstration will give system developers additional confidence to make timely, informed MBFD deployment decisions. Second, we will be completing performance assessments of the diagnostic engine/diagnostic model ensemble both on the flight system and ground-based testbeds to gain confidence in MBFD’s ability to run successfully in a spacecraft’s resource-constrained environment without adversely affecting other on-board activities. Finally, we are capturing our experience in preparing this demonstration in a set of checklists and guidance documents. Current practice includes high-level institutional guidance documents and standards, but at a high level of abstraction that does not necessarily address specific MBFD concerns. The purpose of the new checklists is to provide future mission developers clear, unambiguous, procedure-oriented guidance on assuring MBFD. This paper describes our work in these areas. For the first area, we describe the diagnostic models and updated diagnostic engine that will be used for the on-board demonstration. We describe how the V&V techniques we developed earlier are used to assure model and engine correctness and completeness. For the second area, we identify the performance measurement and assessment techniques used to characterize the diagnostic engine and diagnostic models, and discuss the effect of measured performance on overall mission operation. Finally, we present the checklist and guidance documents and describe how they meet the goals of providing system developers with clear, unambiguous, procedure-oriented guidance on MBFD assurance. We show how the techniques we have developed map into those artifacts.

Nikora, Allen↗