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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 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
NASA NTRS2007

Model Specification for Rework of Aircraft Engine, Power Transmission, and Accessory/Auxiliary Ball and Roller Bearings

This document provides a model specification for the rework and/or repair of bearings used in aircraft engines, helicopter main power train transmissions, and auxiliary bearings determined to be critical by virtue of performance, function, or availability. The rolling-element bearings to be processed under the provisions of this model specification may be used bearings removed after service, unused bearings returned from the field, or certain rejected bearings returned for reinspection and salvage. In commercial and military aircraft application, it has been a practice that rolling-element bearings removed at maintenance or overhaul be reworked and returned to service. Depending on the extent of rework and based upon theoretical analysis, representative life factors (LF) for bearings subject to rework ranged from 0.87 to 0.99 the lives of new bearings. Based on bearing endurance data, 92 percent of the bearing sets that would be subject to rework would result in L(sub 10) lives equaling and/or exceeding that predicted for new bearings. The remaining 8 percent of the bearings have the potential to achieve the analytically predicted life of new bearings when one of the rings is replaced at rework. The potential savings from bearing rework varies from 53 to 82 percent of that of new bearings depending on the cost, size, and complexity of the bearing

Zaretsky, Erwin V.↗
NASA NTRS2007

Using Space Weather Variability in Evaluating the Radiation Environment Design Specifications for NASA's Constellation Program

NASA's Constellation program, initiated to fulfill the Vision for Space Exploration, will create a new generation of vehicles for servicing low Earth orbit, the Moon, and beyond. Space radiation specifications for space system hardware are necessarily conservative to assure system robustness for a wide range of space environments. Spectral models of solar particle events and trapped radiation belt environments are used to develop the design requirements for estimating total ionizing radiation dose, displacement damage, and single event effects for Constellation hardware. We first describe the rationale using the spectra chosen to establish the total dose and single event design environmental specifications for Constellation systems. We then compare variability of the space environment to the spectral design models to evaluate their applicability as conservative design environments and potential vulnerabilities to extreme space weather events

Coffey, Victoria N.↗
NASA NTRS2007

Detergent-Specific Membrane Protein Crystallization Screens

A suite of reagents has been developed for three-dimensional crystallization of integral membranes present in solution as protein-detergent complexes (PDCs). The compositions of these reagents have been determined in part by proximity to the phase boundaries (lower consolute boundaries) of the detergents present in the PDCs. The acquisition of some of the requisite phase-boundary data and the preliminary design of several of the detergent- specific screens was supported by a NASA contract. At the time of expiration of the contract, a partial set of preliminary screens had been developed. This work has since been extended under non-NASA sponsorship, leading to near completion of a set of 20 to 30 different and unique detergent- specific 96-condition screens.

Wiener, Michael↗
NASA NTRS2010

Automata learning algorithms and processes for providing more complete systems requirements specification by scenario generation, CSP-based syntax-oriented model construction, and R2D2C system requirements transformation

Systems, methods and apparatus are provided through which in some embodiments, automata learning algorithms and techniques are implemented to generate a more complete set of scenarios for requirements based programming. More specifically, a CSP-based, syntax-oriented model construction, which requires the support of a theorem prover, is complemented by model extrapolation, via automata learning. This may support the systematic completion of the requirements, the nature of the requirement being partial, which provides focus on the most prominent scenarios. This may generalize requirement skeletons by extrapolation and may indicate by way of automatically generated traces where the requirement specification is too loose and additional information is required.

Hinchey, Michael G.↗
NASA NTRS2010

An Integrated, Evidence-Based Approach to Transitioning to Operations: Specifications for Future Replacement Lights on ISS

The International Space Station (ISS) currently uses General Luminaire Assemblies (GLAs) as its primary light source. These GLAs are composed of fluorescent lighting and are integrated into the electrical system on Station. Seventy seven of these units are distributed throughout the vehicle, and many of the lights, having reached their lifespan, are no longer functional; while backup panels are available on orbit, it is anticipated that the supplies of fluorescents on the station will be exhausted by 2015. The ISS vehicle office is therefore preparing to replace all of the GLAs, with Solid State Light Assemblies (SSLAs) composed of white Light Emitting Diodes (LEDs). In the Spring of 2010, an announcement for the replacement lights was released. The announcement specified that proposed lighting systems should use LED technology, given certain power draw restrictions and no changes to how the lights are currently controlled (a central on/off switch per node, and a dial to turn on/off and increase brightness on each lighting unit). The replacement lights are to follow current specifications for brightness levels (lux) and color temperature (degrees Kelvin, or K). Reportedly, the lighting on orbit is dim and suboptimal. The average brightness of the lights (given all lights within a node are operational) is 291 lux; by comparison, recommended office lighting ranges from 200 to 500 lux, and daylight ranges on a typical overcast day, consists of 10,000 to 25,000 lux. Representatives from NASA Behavioral Health and Performance Element (BHP) and Human Factors and Habitability identified that maintaining current brightness levels limits visual acuity, work space, and the use of light as a countermeasure for improving circadian entrainment, hastening phase shifting, evoking acute alertness and enhancing performance. Revised lighting specifications are therefore needed to optimize the replacement lights for the ISS.

Leveton, Lauren↗
NASA NTRS2010

Environmental Impact Specification for Direct Space Weathering of Kuiper Belt and Oort Cloud Objects

The Direct Space Weathering Project of NASA's Outer Planets Research Program addresses specification of the plasma and energetic particle environments for irradiation and surface chemical processing of icy bodies in the outer solar system and the local interstellar medium. Knowledge of the radiation environments is being expanded by ongoing penetration of the twin Voyager spacecraft into the heliosheath boundary region of the outer heliosphere and expected emergence within the next decade into the very local interstellar medium. The Voyager measurements are being supplemented by remote sensing from Earth orbit of energetic neutral atom emission from this boundary region by NASA's Interstellar Boundary Explorer (IBEX). Although the Voyagers long ago passed the region of the Classical Kuiper Belt, the New Horizons spacecraft will encounter Pluto in 2015 and thereafter explore one or more KBOs, meanwhile providing updated measurements of the heliospheric radiation environment in this region. Modeling of ion transport within the heliosphere allows specification of time-integrated irradiation effects while the combination of Voyager and IBEX data supports projection of the in-situ measurements into interstellar space beyond the heliosheath. Transformation of model ion flux distributions into surface sputtering and volume ionization profiles provides a multi-layer perspective for space weathering impact on the affected icy bodies and may account for some aspects of color and compositional diversity. Other important related factors may include surface erosion and gardening by meteoritic impacts and surface renewal by cryovolcanism. Chemical products of space weathering may contribute to energy resources for the latter.

Cooper, John F.↗
NASA NTRS2011

Radiation Specifications for Fission Power Conversion Component Materials

NASA has been supporting design studies and technology development that could provide power to an outpost on the moon, Mars, or an asteroid. One power-generation system that is independent of sunlight or power-storage limitations is a fission-based power plant. There is a wealth of terrestrial system heritage that can be transferred to the design and fabrication of a fission power system for space missions, but there are certain design aspects that require qualification. The radiation tolerance of the power conversion system requires scrutiny because the compact nature of a space power plant restricts the dose reduction methodologies compared to those used in terrestrial systems. An integrated research program has been conducted to establish the radiation tolerance of power conversion system-component materials. The radiation limit specifications proposed for a Fission Power System power convertor is 10 Mrad ionizing dose and 5 x 10(exp 14) neutron per square centimeter fluence for a convertor operating at 150 C. Specific component materials and their radiation tolerances are discussed. This assessment is for the power convertor hardware; electronic components are not covered here.

Bowman, Cheryl L.↗
NASA NTRS2011

Automated Verification of Specifications with Typestates and Access Permissions

We propose an approach to formally verify Plural specifications based on access permissions and typestates, by model-checking automatically generated abstract state-machines. Our exhaustive approach captures all the possible behaviors of abstract concurrent programs implementing the specification. We describe the formal methodology employed by our technique and provide an example as proof of concept for the state-machine construction rules. The implementation of a fully automated algorithm to generate and verify models, currently underway, provides model checking support for the Plural tool, which currently supports only program verification via data flow analysis (DFA).

Siminiceanu, Radu I.↗
NASA NTRS2011

International Low Impact Docking System (iLIDS) Project Technical Requirements Specification, Revision F

The NASA Docking System (NDS) is NASA's implementation for the emerging International Docking System Standard (IDSS) using low impact docking technology. The NASA Docking System Project (NDSP) is the International Space Station (ISS) Program's project to produce the NDS, Common Docking Adapter (CDA) and Docking Hub. The NDS design evolved from the Low Impact Docking System (LIDS). The acronym international Low Impact Docking System (iLIDS) is also used to describe this system as well as the Government Furnished Equipment (GFE) project designing the NDS for the NDSP. NDS and iLIDS may be used interchangeability. This document will use the acronym iLIDS. Some of the heritage documentation and implementations (e.g., software command names, requirement identification (ID), figures, etc.) used on NDS will continue to use the LIDS acronym. This specification defines the technical requirements for the iLIDS GFE delivered to the NDSP by the iLIDS project. This document contains requirements for two iLIDS configurations, SEZ29101800-301 and SEZ29101800-302. Requirements with the statement, iLIDS shall, are for all configurations. Examples of requirements that are unique to a single configuration may be identified as iLIDS (-301) shall or iLIDS (-302) shall. Furthermore, to allow a requirement to encompass all configurations with an exception, the requirement may be designated as iLIDS (excluding -302) shall. Verification requirements for the iLIDS project are identified in the Verification Matrix (VM) provided in the iLIDS Verification and Validation Document, JSC-63966. The following definitions differentiate between requirements and other statements: Shall: This is the only verb used for the binding requirements. Should/May: These verbs are used for stating non-mandatory goals. Will: This verb is used for stating facts or declaration of purpose. A Definition of Terms table is provided in Appendix B to define those terms with specific tailored uses in this document.

Lewis, James L.↗
NASA NTRS1993

General Design Specification Total Ozone Mapping Spectrometer

This specification establishes the general requirements for the Total Ozone Mapping Spectrometer (TOMS) and its major components, and is the main systems-engineering tool for the TOMS program. This document shall be the primary technical specification for the TOMS FM-3 and later instruments, not including ground support equipment.

Source record↗
NASA NTRS2012

Compound-Specific Isotopic Analysis of Meteoritic Amino Acids as a Tool for Evaluating Potential Formation Pathways

Measurements of stable hydrogen, carbon, and nitrogen isotopic ratios (delta D, delta C-13, delta N-15) of organic compounds can reveal information about their origin and formation pathways. Several formation mechanisms and environments have been postulated for the amino acids detected in carbonaceous chondrites. As each proposed mechanism utilizes different precursor molecules, the isotopic signatures of the resulting amino acids may point towards the most likely of these proposed pathways. The technique of gas chromatography coupled with mass spectrometry and isotope ratio mass spectrometry provides compound-specific structural and isotopic information from a single splitless injection, enhancing the amount of information gained from small amounts of precious samples such as carbonaceous chondrites. We have applied this technique to measure the compound-specific C, N, and H isotopic ratios of amino acids from seven CM and CR carbonaceous chondrites. We are using these measurements to evaluate predictions of expected isotopic enrichments from potential formation pathways and environments, leading to a better understanding of the origin of these compounds.

Elsila, Jamie E.↗
NASA NTRS2012

Method for Predicting the Energy Characteristics of Li-Ion Cells Designed for High Specific Energy

Novel electrode materials with increased specific capacity and voltage performance are critical to the NASA goals for developing Li-ion batteries with increased specific energy and energy density. Although performance metrics of the individual electrodes are critically important, a fundamental understanding of the interactions of electrodes in a full cell is essential to achieving the desired performance, and for establishing meaningful goals for electrode performance in the first place. This paper presents design considerations for matching positive and negative electrodes in a viable design. Methods for predicting cell-level performance, based on laboratory data for individual electrodes, are presented and discussed.

Bennett, William, R.↗
NASA NTRS2012

Architectural Implementation of NASA Space Telecommunications Radio System Specification

This software demonstrates a working implementation of the NASA STRS (Space Telecommunications Radio System) architecture specification. This is a developing specification of software architecture and required interfaces to provide commonality among future NASA and commercial software-defined radios for space, and allow for easier mixing of software and hardware from different vendors. It provides required functions, and supports interaction with STRS-compliant simple test plug-ins ("waveforms"). All of it is programmed in "plain C," except where necessary to interact with C++ plug-ins. It offers a small footprint, suitable for use in JPL radio hardware. Future NASA work is expected to develop into fully capable software-defined radios for use on the space station, other space vehicles, and interplanetary probes.

Peters, Kenneth J.↗
NASA NTRS2013

Direct Energy Conversion for Low Specific Mass In-Space Power and Propulsion

"Changing the game" in space exploration involves changing the paradigm for the human exploration of the Solar System, e.g, changing the human exploration of Mars from a three-year epic event to an annual expedition. For the purposes of this assessment an "annual expedition" capability is defined as an in-space power & propulsion system which, with launch mass limits as defined in NASA s Mars Architecture 5.0, enables sending a crew to Mars and returning them after a 30-day surface stay within one year, irrespective of planetary alignment. In this work the authors intend to show that obtaining this capability requires the development of an in-space power & propulsion system with an end-to-end specific mass considerably less than 3 kg/kWe. A first order energy balance analysis reveals that the technologies required to create a system with this specific mass include direct energy conversion and nuclear sources that release energy in the form of charged particle beams. This paper lays out this first order approximation and details these conclusions.

Scott, John H.↗
NASA NTRS2005

Thermal Conductivity and Specific Heat Measurements of Candidate Structural Materials for the JWST Optical Bench

The James Webb Space Telescope will include an optical bench known as the integrated science instrument module (ISIM). Candidate structural materials for the ISIM must have low density, high stiffness, high thermal conductivity, and low thermal expansion coefficient at the operating temperature of 30 Kelvin. The specific heat is also important in modeling the on-orbit cooldown. We built two different systems for measuring the thermal conductivity and specific heat of samples between 4 Kelvin and 290 Kelvin. Both experiments were carefully designed to minimize potential errors due to radiative heat transfer. We chose the cooling system and instrumentation to allow long-term unattended operation. Software was developed to automate each experiment. It used an algorithm designed to ensure that each system was in thermal equilibrium before a measurement was taken. We describe the two experiments and present the data.

Canavan, E. R.↗
NASA NTRS2013

The GLAS Standard Data Products Specification--Level 2, Version 9

The Geoscience Laser Altimeter System (GLAS) is the primary instrument for the ICESat (Ice, Cloud and Land Elevation Satellite) laser altimetry mission. ICESat was the benchmark Earth Observing System (EOS) mission for measuring ice sheet mass balance, cloud and aerosol heights, as well as land topography and vegetation characteristics. From 2003 to 2009, the ICESat mission provided multi-year elevation data needed to determine ice sheet mass balance as well as cloud property information, especially for stratospheric clouds common over polar areas. It also provided topography and vegetation data around the globe, in addition to the polar-specific coverage over the Greenland and Antarctic ice sheets.This document defines the Level-2 GLAS standard data products. This document addresses the data flow, interfaces, record and data formats associated with the GLAS Level 2 standard data products. The term standard data products refers to those EOS instrument data that are routinely generated for public distribution. The National Snow and Ice Data Center (NSDIC) distribute these products. Each data product has a unique Product Identification code assigned by the Senior Project Scientist. The Level 2 Standard Data Products specifically include those derived geophysical data values (i.e., ice sheet elevation, cloud height, vegetation height, etc.). Additionally, the appropriate correction elements used to transform the Level 1A and Level 1B Data Products into Level 2 Data Products are included. The data are packaged with time tags, precision orbit location coordinates, and data quality and usage flags.

Lee, Jeffrey E.↗
NASA NTRS2013

Simple Benchmark Specifications for Space Radiation Protection

This report defines space radiation benchmark specifications. This specification starts with simple, monoenergetic, mono-directional particles on slabs and progresses to human models in spacecraft. This report specifies the models and sources needed to what the team performing the benchmark needs to produce in a report. Also included are brief descriptions of how OLTARIS, the NASA Langley website for space radiation analysis, performs its analysis.

Singleterry, Robert C. Jr.↗
NASA NTRS2013

Engineering Specification for Large-aperture UVO Space Telescopes Derived from Science Requirements

An advanced large aperture UV/optical UVO space telescope is required for the next generation of astrophysics and exoplanet science. The science requirements of proposed exoplanet and astrophysics missions were used to determine the encircled energy, point spread function stability and thermal environment requirements. These requirements then determine the optical wavefront specification for potential telescope assemblies which can fit inside current and planned launch vehicles. The optical wavefront specification becomes the top level of the error budget that is split into various sources that control the structural, thermal and optical design.

Stahl, H. Philip↗