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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Harvesting Isotopically Pure Ac-225 from Ra-225 Produced in Thorium Target Spallation Reaction

A method for isolating Ra-225 from linear accelerator irradiated Th metal chemical processing waste streams has been established. Separating Ra-225 from the complex matrix following proton irradiation of Th metal provides a source of isotopically pure Ac-225 free of the Ac-227 impurity that is present in accelerator-produced Ac-225. Ra isotopes are first separated from the irradiated Th target via cation exchange methods. Importantly, the Ra-containing fraction is cleaned from residual citrate via dilute nitric acid washes (0.5 M) on AG50W-X8 resin. The mixed Ra isotopes are then further purified from Ba-140 impurity using a Sr resin column. Ra elutes through the resin with successive washes of 2.5 M HNO 3 while Ba-140 is retained. Ac-225 is then harvested by loading the Ra content onto an AG50W-X8 cation exchange column where the Ra-225 parent is eluted with 2.5 M HNO 3 before the Ac-225 daughter is eluted with 8 M HNO 3 .

07 ISOTOPE AND RADIATION SOURCES↗
NASA NTRS1973

Artic and subarctic environmental analyses utilizing ERTS-1 imagery. Discipline 8: Interpretation techniques development. Subdiscipline C: Classfication and pattern recognition

The author has identified the following significant results. Uncontrolled photo mosaics of ERTS-1 imagery using MSS band 5 and 7 at a scale of 1:1,000,000 were used to make a preliminary surficial geology map in northcentral Alaska. Seven distinct geologic units were recognized, defined, and mapped directly on a photo mosaic. Results are closely correlated with published surficial geology maps. Eight MSS images were examined to test utility of ERTS data in studies of coastal processes and stream hydrology, and in the identification and interpretation of geomorphic features throughout Alaska. The feasibility of using ERTS-1 data to map structural lineaments is well illustrated on a mosaic of 8, band 5 MSS images. Along the northern edge of the Brooks Range one lineament can be followed the entire width of the mosaic, a distance of 225 miles. Two nearly parallel lineaments can be seen running along the northern and southern edges of the Schwatka Mountains. About 135 miles south of these two lineaments another series located in the Chitanana River region can be followed for 45 miles. These lineaments appear to be faults, and it is interesting to note that the Yukon River parallels these and appears to be structurally controlled.

Anderson, D. M.↗
NASA NTRS1975

Stream pattern analysis using optical processing of ERTS imagery of Kansas

A spatial frequency analysis was carried out to obtain large-scale geologic and other ground pattern spatial frequency and orientational data from an optical data processing system using Earth Resources Technology Satellite-1 (ERTS-1) imagery of Kansas as input. The Diffraction Pattern Sampling Unit (DPSU) of the optical data processing system consists of a photodiode array containing 32 wedge-shaped photodiodes and 32 annular ring diodes. The curve obtained from the intensity distribution of the frequency spectrum yielded by the ring diodes gives the spatial frequency contributions due to ground features on the image. The curve obtained from the wedge-shaped diodes indicates the orientation of features in the sample area. Ten sample sites were used for each of eight geologic-physiographic regions. Comparison of ERTS-1 images with their respective spatial frequency and orientational curves reveals that preferred orientations of drainage produce recognizable peaks.

Mccauley, J.↗
NASA NTRS1976

Oxidation of contaminative methane traces with radio-frequency discharge

An 11.8 MHz glow discharge was used to oxidize trace levels of methane in oxygen. The concentration of methane can be reduced by three orders of magnitude. The effects of power (0-400 W), flow rate (10-1000 cc-STP/min) and concentration (70-8000 ppm) were investigated at pressures ranging from 50 torr to almost 1 atm. No organic reaction products were detected in the treated gas stream. The process may prove useful for the removal of atmospheric trace contaminants at ambient pressure.

Flamm, D. L.↗
NASA NTRS1987

Program for Automated Real-Time Monitoring

Process-control decisions made by applying rules to process data streams. Expert System Executive computer program demonstrates feasibility of automated real-time monitoring. Using Executives knowledge of system formally coded as set of rules specifying actions taken under various conditions. Program makes inferences about observed data based on rules. Written in C language.

Goodrum, Glenn R.↗
NASA NTRS1988

Intelligent interfaces for expert systems

Vital to the success of an expert system is an interface to the user which performs intelligently. A generic intelligent interface is being developed for expert systems. This intelligent interface was developed around the in-house developed Expert System for the Flight Analysis System (ESFAS). The Flight Analysis System (FAS) is comprised of 84 configuration controlled FORTRAN subroutines that are used in the preflight analysis of the space shuttle. In order to use FAS proficiently, a person must be knowledgeable in the areas of flight mechanics, the procedures involved in deploying a certain payload, and an overall understanding of the FAS. ESFAS, still in its developmental stage, is taking into account much of this knowledge. The generic intelligent interface involves the integration of a speech recognizer and synthesizer, a preparser, and a natural language parser to ESFAS. The speech recognizer being used is capable of recognizing 1000 words of connected speech. The natural language parser is a commercial software package which uses caseframe instantiation in processing the streams of words from the speech recognizer or the keyboard. The systems configuration is described along with capabilities and drawbacks.

Villarreal, James A.↗
NASA NTRS1994

Ulysses near-ecliptic observations of differential flow between protons and alphas in the solar wind

The evolution of differential streaming between protons and alpha particles in the solar wind was observed with the solar wind plasma experiment on the Ulysses spacecraft over the solar range of 1.15 to 5.40 AU between November 18, 1990, and May 5, 1992. The correlation of the difference in ion speeds, Delta V = the absolute value of V(sub alpha) - the absolute value of V(sub p), with the proton speed V(sub p) observed by other spacecraft at solar distances less than or equal to 1 AU disappeared at approximately 2 AU. At solar distances greater than or equal to 2.85 AU, the largest values of both V(sub alpha p) = the absolute value of V(sub alpha p) = the absolute value of V(sub alpha) - V(sub p) and the absolute value of Delta V were found in the interaction regions on the leading edges of high-speed streams. The differential streaming was typically enhanced just downstream of strong forward and reverse shocks, and large negative values of Delta V were frequently encountered in the interaction regions. A correlation between V(sub alpha p) and the ratio tau(sub zero)/tau(sub e) of Coulomb collision time to expansion time was observed at all distances, but it is suggested that at the larger values of tau(sub zero)/tau(sub e) observed correlation may arise from enhanced production of differential streaming by processes that also increase the entropy of the solar wind protons.

Neugebauer, M.↗
NASA NTRS1996

Configurable Hardware And Software For Multiple Related Uses

Control Monitor Unit (CMU) is system of configurable hardware and software undergoing development for use in controlling and monitoring complex systems of equipment. Provides comprehensive array of capabilities for such functions as processing equipment-test data for calibration and diagnosis, controlling operation of equipment in real time, simulating operation of equipment, and processing large streams of scientific-measurement data. Automates many of ground operations involved in preparing and testing spacecraft prior to launch. Also useful in variety of similar applications; for example, testing aircraft, ships, power plants, and automated production lines.

Uhrlaub, David R.↗
NASA NTRS2002

Repetition blindness has a perceptual locus: evidence from online processing of targets in RSVP streams

Four experiments tested whether repetition blindness (RB; reduced accuracy reporting repetitions of briefly displayed items) is a perceptual or a memory-recall phenomenon. RB was measured in rapid serial visual presentation (RSVP) streams, with the task altered to reduce memory demands. In Experiment 1 only the number of targets (1 vs. 2) was reported, eliminating the need to remember target identities. Experiment 2 segregated repeated and nonrepeated targets into separate blocks to reduce bias against repeated targets. Experiments 3 and 4 required immediate "online" buttonpress responses to targets as they occurred. All 4 experiments showed very strong RB. Furthermore, the online response data showed clearly that the 2nd of the repeated targets is the one missed. The present results show that in the RSVP paradigm, RB occurs online during initial stimulus encoding and decision making. The authors argue that RB is indeed a perceptual phenomenon.

Form Perception↗
NASA NTRS2007

Compression of a Data Stream by Selection among a Set of Compression Tools

A stream of raw data is compressed prior to transmissio in a communication channel by a system which includes modules for choosing a current segment of the raw data stream for processing and defining a set of operators for representing data segments by a mathematical operation and parameters thereof. The system performs a competitive evaluation of different tools comprising different combinations of one or more of the operators and the parameters threrof with respect to the current data segment in order to determine relative abilities among the different tools to reduce the number of bits required to represent the current data segment. The system then selects a tool and a set of parameters thereof found in the competitive evaluation to have a superior ability relative to others of the different tools to reduce a number of bits required to represent the current data segment.

Arlid, Bertelrud↗
NASA NTRS1990

Converting a carbon preform object to a silicon carbide object

A process for converting in depth a carbon or graphite preform object to a silicon carbide object, silicon carbide/silicon object, silicon carbide/carbon-core object, or a silicon carbide/silicon/carbon-core object, by contacting it with silicon liquid and vapor over various lengths of contact time in a reaction chamber. In the process, a stream comprised of a silicon-containing precursor material in gaseous phase below the decomposition temperature of said gas and a coreactant, carrier or diluent gas such as hydrogen is passed through a hole within a high emissivity, thin, insulating septum into the reaction chamber above the melting point of silicon. The thin septum has one face below the decomposition temperature of the gas and an opposite face exposed to the reaction chamber. Thus, the precursor gas is decomposed directly to silicon in the reaction chamber. Any stream of decomposition gas and any unreacted precursor gas from the reaction chamber is removed. A carbon or graphite preform object placed in the reaction chamber is contacted with the silicon. The carbon or graphite preform object is recovered from the reactor chamber after it has been converted to a desired silicon carbide, silicon and carbon composition.

Levin, Harry↗
NASA NTRS1989

Process for coating an object with silicon carbide

A process for coating a carbon or graphite object with silicon carbide by contacting it with silicon liquid and vapor over various lengths of contact time. In the process, a stream of silicon-containing precursor material in gaseous phase below the decomposition temperature of said gas and a co-reactant, carrier or diluent gas such as hydrogen is passed through a hole within a high emissivity, thin, insulating septum into a reaction chamber above the melting point of silicon. The thin septum has one face below the decomposition temperature of the gas and an opposite face exposed to the reaction chamber. The precursor gas is decomposed directly to silicon in the reaction chamber. A stream of any decomposition gas and any unreacted precursor gas from said reaction chamber is removed. The object within the reaction chamber is then contacted with silicon, and recovered after it has been coated with silicon carbide.

Levin, Harry↗
NASA NTRS2009

Auto-Generated Semantic Processing Services

Auto-Generated Semantic Processing (AGSP) Services is a suite of software tools for automated generation of other computer programs, denoted cross-platform semantic adapters, that support interoperability of computer-based communication systems that utilize a variety of both new and legacy communication software running in a variety of operating- system/computer-hardware combinations. AGSP has numerous potential uses in military, space-exploration, and other government applications as well as in commercial telecommunications. The cross-platform semantic adapters take advantage of common features of computer- based communication systems to enforce semantics, messaging protocols, and standards of processing of streams of binary data to ensure integrity of data and consistency of meaning among interoperating systems. The auto-generation aspect of AGSP Services reduces development time and effort by emphasizing specification and minimizing implementation: In effect, the design, building, and debugging of software for effecting conversions among complex communication protocols, custom device mappings, and unique data-manipulation algorithms is replaced with metadata specifications that map to an abstract platform-independent communications model. AGSP Services is modular and has been shown to be easily integrable into new and legacy NASA flight and ground communication systems.

Davis, Rodney↗
NASA NTRS2005

Launch Commit Criteria Monitoring Agent

The Spaceport Processing Systems Branch at NASA Kennedy Space Center has developed and deployed a software agent to monitor the Space Shuttle's ground processing telemetry stream. The application, the Launch Commit Criteria Monitoring Agent, increases situational awareness for system and hardware engineers during Shuttle launch countdown. The agent provides autonomous monitoring of the telemetry stream, automatically alerts system engineers when predefined criteria have been met, identifies limit warnings and violations of launch commit criteria, aids Shuttle engineers through troubleshooting procedures, and provides additional insight to verify appropriate troubleshooting of problems by contractors. The agent has successfully detected launch commit criteria warnings and violations on a simulated playback data stream. Efficiency and safety are improved through increased automation.

Semmel, Glenn S.↗
NASA NTRS2019

Rapid Development of the Seeker Free-Flying Inspector Guidance, Navigation, and Control System

Seeker is an automated extravehicular free-flying inspector CubeSat designed and built in-house at the Johnson Space Center (JSC). As a Class 1E project funded by the International Space Station (ISS) Program, Seeker had a stream-lined process to flight certification, but the vehicle had to be designed, developed, tested, and delivered within approximately one year after authority to proceed (ATP) and within a $1.8 million budget. These constraints necessitated an expedited Guidance, Navigation, and Control (GNC) development schedule. Development began with a navigation sensor trade study using Linear Covariance (LinCov) analysis and a rapid sensor down-selection process, resulting in the use of commercial off-the-shelf (COTS) sensors which could be procured quickly and subjected to in-house environmental testing to qualify them for flight. A neural network was used to enable a COTS camera to provide bearing measure-ments for visual navigation. The GNC flight software (FSW) algorithms utilized lean development practices and leveraged the Core Flight Software (CFS) architecture to rapidly develop the GNC system, tune the system parameters, and verify performance in simulation. This pace was anchored by several Hardware-Software Integration (HSI) milestones, which forced the Seeker GNC team to develop the interfaces both between hardware and software and between the GNC domains early in the project and to enable a timely delivery.

Sullivan, Jake↗
NASA NTRSDate not supplied

Suborbital Testing of the OSCAR Trash-to-Gas System

With the sustained human exploration of nearby celestial bodies on the horizon, a renewed outlook on crew waste management must be realized. Current waste management strategies aboard the International Space Station become impractical as we venture beyond low Earth orbit. Furthermore, for future exploration missions, extracting resources from various waste streams becomes increasingly advantageous. One method of combatting the long-duration waste management problem is by thermally degrading solid and liquid crew waste items into a chemically inert, ventable gas stream, a process known as Trash-to-Gas. The Orbital Syngas/Commodity Augmentation Reactor (OSCAR) is the state-of-the-art Trash-to-Gas system which has been designed to explore microgravity Trash-to-Gas concepts for improved mass/volume reduction and resource recovery from waste. OSCAR is a subscale testbed design that supports the NASA Logistics Reduction project under the Advanced Exploration Systems Program and Space Technology Mission Directorate Flight Opportunities Program to determine the feasibility of Trash-to-Gas technology for future use on long duration space missions. OSCAR has flown on two suborbital flight demonstrations aboard Blue Origin’s New Shepard launch vehicle. This paper presents a high-level comparative analysis of these microgravity test campaigns with Earth gravity laboratory experiments. Solid-to-gas conversion, gas production & composition, and reactor temperature & pressure are compared to highlight the operational factors and performance differences within the microgravity environment for future optimization.

Ray P Pitts↗
NASA NTRS2015

Prioritized Contact Transport Stream

A detection process, contact recognition process, classification process, and identification process are applied to raw sensor data to produce an identified contact record set containing one or more identified contact records. A prioritization process is applied to the identified contact record set to assign a contact priority to each contact record in the identified contact record set. Data are removed from the contact records in the identified contact record set based on the contact priorities assigned to those contact records. A first contact stream is produced from the resulting contact records. The first contact stream is streamed in a contact transport stream. The contact transport stream may include and stream additional contact streams. The contact transport stream may be varied dynamically over time based on parameters such as available bandwidth, contact priority, presence/absence of contacts, system state, and configuration parameters.

Hunt, Walter Lee, Jr.↗