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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 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

Using Fractional Clock-Period Delays in Telemetry Arraying

A set of special digital all-pass finite-impulse- response (FIR) filters produces phase shifts equivalent to delays that equal fractions of the sampling or clock period of a telemetry-data-processing system. These filters have been used to enhance the arraying of telemetry signals that have been received at multiple ground stations from spacecraft (see figure). Somewhat more specifically, these filters have been used to align, in the time domain, the telemetry-data sequences received by the various antennas, in order to maximize the signal-to-noise ratio of the composite telemetric signal obtained by summing the signals received by the antennas. The term arraying in this context denotes a method of enhanced reception of telemetry signals in which several antennas are used to track a single spacecraft. Each antenna receives a signal that comprises a sum of telemetry data plus noise, and these sum data are sent to an arraying combiner for processing. Correlation is the means used to align the set of data from one antenna with that from another antenna. After the data from all the antennas have been aligned in the time domain, they are all added together, sample by sample.

Fort, David↗
NASA NTRS1986

The thermoluminescence sensitivity-metamorphism relationship in ordinary chondrites - Experimental data on the mechanism and implications for terrestrial systems

Hydrothermal annealing experiments have been performed on samples of the Sharps meteorite in order to investigate the mechanism responsible for the metamorphism-related, 10-to-the-5th-fold range in the thermoluminescence (TL) sensitivity in ordinary chondrites. Duplicate 50 mg samples of meteorite were annealed under the following conditions: (1) 168 h at 785 C and 1 kbar; (2) the same time, temperature and pressure, but with 2 wt pct water; (3) 174 h at 855 C and 0.77 kbar with 2 wt pct water and 2 molal sodium disilicate (NadiSi); (4) the same time, temperature and pressure as the preceding samples, but with 10 wt pct H2O and 2 molal NadiSi. Samples annealed under the first three sets of conditions showed little or no change in their TL sensitivities, however the samples annealed with 10 wt pct water and 2 molal NadiSi showed a three-fold to 10-fold increase in TL sensitivity, and the temperature of the TL peak was suggestive of feldspar in the high-temperature form. It is suggested that these data are consistent with the TL sensitivity-metamorphism relationship in ordinary chondrites being due to the formation of the TL phosphor, feldspar, by the crystallization of chondrule glass.

Guimon, R. K.↗
NASA NTRS2004

Tools for describing the reference architecture for space data systems

This paper has briefly presented the Reference Architecture for Space Data Systems (RASDS) that is being developed by the CCSDS Systems Architecture Working Group (SAWG). The SAWG generated some sample architectures (spacecraft onboard architectures, space link architectures, cross-support architectures) using this RASDS approach, and RASDS was proven to be a powerful tool for describing and relating different space data system architectures.

communication↗
NASA NTRS1984

Case study of sample spacing in planar near-field measurement of high gain antennas

Far field antenna patterns can be reconstructed from planar near field measurements acquired at a sample spacing of lambda/2 or less. For electrically large antennas, sampling at the Nyquist rate may result in errors due to system electronic drift over long acquisition times. The computer capacity may limit the largest size of the near field data set. The requirement to sample at the Nyquist rate is relaxed for high gain antennas which concentrate most of the radiated energy into a small angular region of the far field. The criteria for sample spacing at greater than lambda/e through the use of a priori information of the antenna radiation characteristics are presented. Far field patterns of a 30 GHz dual offset reflector system with a 2.7 m parabolic main reflector are computed from near field data obtained at sample spacings ranging from 0.1 lambda to 10 lambda. The effects of sampling interval and spectrum cutoff on the far field patterns are discussed.

Acosta, R. J.↗
NASA NTRS2022

2022 Annual Report: Culture-Based Environmental Microbiology Monitoring of Crop-based Space Food Systems (Veggie Monitoring)

Crewmembers live and work in a closed environment that is monitored to ensure their health and safety. Quarterly monitoring of the microorganisms in the International Space Station (ISS) environment supports crew safety and contributes to a large set of environmental microbial data from the air, surface, and water samples that are collected. This study leverages quarterly operational Environmental Health System (EHS) sampling by collecting additional microbial samples from the surface of the station’s Veggie plant production system. Longer exploration missions may require spaceflight-based systems for growth of plants, and this investigation is expected to provide additional data to help establish requirements to protect these systems, plants, and crew, mitigating adverse microbial exposure.

Tanner Hamilton↗
NASA NTRS1972

Magnitude error bounds for sampled-data frequency response obtained from the truncation of an infinite series, and compensator improvement program

The frequency response method of analyzing control system performance is discussed, and the difficulty of obtaining the sampled frequency response of the continuous system is considered. An upper bound magnitude error equation is obtained which yields reasonable estimates of the actual error. Finalization of the compensator improvement program is also reported, and the program was used to design compensators for Saturn 5/S1-C dry workshop and Saturn 5/S1-C Skylab.

Mitchell, J. R.↗
NASA NTRSDate not supplied

Repurposing Drilling Control Diagnostics for Subsurface Edge Detection and Boundary Advisement During Planetary Drilling

Informed decision-making during lunar drilling and sampling missions will require data monitoring tools and specialized ground data systems. Accurate and updated situational awareness, with ongoing data monitoring, is critical for timely responses by to incoming science data. Traverse plans and scheduled activities may need to be flexibly changed in order to react to unexpected data or situations. Unlike (for example) Mars missions, the relative lightspeed closeness of the Moon allows for near-real-time ground processing of incoming mission and instrument data. An Apollo-class lunar regolith drill will in a sense “travel” a meter or two vertically at a given subsurface characterization site. As the drill penetrates into lunar regolith, it is likely to encounter a range of material densities, orientations, fracture toughness, and (perhaps) ice percentages. Lunar drill telemetry can provide science teams with a valuable first look into the subsurface structure, the regolith bulk properties, and constituents at each drilled site. Real-time AI-based recognition and reaction to downhole situations has been developed for automated deeper drilling on Mars and beyond. We can leverage the same knowledge bases and pattern-matching as areal-time interpreter of the subsurface, a situational awareness tool during drilling operations. We recently (Sept. 2019) demonstrated this AI drilling monitoring and analysis capability, in control of in-situ drilling and sampling operations, mounted on a KREX-2 rover in Chile’s Atacama Desert. Terrestrial automated drilling log analyses in oil exploration have used similar machine learning techniques in classifying and identifying features in drilling logs –but these typically are designed assuming a drilling fluid influencing downhole measurements and data (permeability, resistivity). Drilling models and existing AI software designed to detect and respond to drilling faults and hard materials can be repurposed, for near-real-time (ground-based) interpretation of drilling telemetry –a potentially valuable advisory tool for strata boundaries and changes in drilling parameters. On the Moon, this approach could be used to study the structure and to some extent the composition of lunar regolith vs. borehole depth, based on recognizable variations in fracture hardness, drilling energy and penetration rates while actively drilling. Since the early 2000s, a series of increasingly-capable real-time drilling telemetry interpretation and characterization software tools have been developed. These subsurface models and software tools have monitored the real-time drilling data received, and automatically identified changes in drill behavior (e.g., encountering a harder target layer, bit inclusions, drill choking due to infall downhole, and others) correlating these with subsurface structures and features. We discuss the mappings between drill borehole parameters, faults or events detected, and modeled changes in rock layer boundaries, in examples drawn from field testing at analog sites in an Arctic impact crater, Rio Tinto, and Chile’s Atacama Desert. These demonstrate how subsurface structural boundaries led to fault detections and responses by the software.

drilling advisor↗
NASA NTRS1996

Automation of Command and Data Entry in a Glovebox Work Volume: An Evaluation of Data Entry Devices

The present study was designed to examine the human-computer interface for data entry while performing experimental procedures within a glovebox work volume in order to make a recommendation to the Space Station Biological Research Project for a data entry system to be used within the Life Sciences Glovebox. Test subjects entered data using either a manual keypad, similar to a standard computer numerical keypad located within the glovebox work volume, or a voice input system using a speech recognition program with a microphone headset. Numerical input and commands were programmed in an identical manner between the two systems. With both electronic systems, a small trackball was available within the work volume for cursor control. Data, such as sample vial identification numbers, sample tissue weights, and health check parameters of the specimen, were entered directly into procedures that were electronically displayed on a video monitor within the glovebox. A pen and paper system with a 'flip-chart' format for procedure display, similar to that currently in use on the Space Shuttle, was used as a baseline data entry condition. Procedures were performed by a single operator; eight test subjects were used in the study. The electronic systems were tested under both a 'nominal' or 'anomalous' condition. The anomalous condition was introduced into the experimental procedure to increase the probability of finding limitations or problems with human interactions with the electronic systems. Each subject performed five test runs during a test day: two procedures each with voice and keypad, one with and one without anomalies, and one pen and paper procedure. The data collected were both quantitative (times, errors) and qualitative (subjective ratings of the subjects).

Steele, Marianne K.↗
NASA NTRS1977

NASA Global Atmospheric Sampling Program (GASP) data report for tape VL0006

The NASA Global Atmospheric Sampling Program (GASP) is obtaining measurements of atmospheric trace constituents in the upper troposphere and lower stratosphere using fully automated air sampling systems on board several commercial B-747 aircraft in routine airline service. Atmospheric ozone, and related flight and meteorological data were obtained during 245 flights of a Qantas Airways of Australia B-747 and two Pan American World Airways B-747s from July 1976 through September 1976. In addition, whole air samples, obtained during three flights, were analyzed for trichlorofluoromethane, and filter samples, obtained during four flights, were analyzed for sulfates, nitrates, fluorides, and chlorides. Flight routes and dates, instrumentation, data processing procedures, data tape specifications, and selected analyses are discussed.

Gauntner, D. J.↗
NASA NTRS1988

Formulation and verification of frequency response system identification techniques for large space structures

For the past several years much effort has been given to the development of techniques for designing control systems for large space structures (LSS's). The main objective of these efforts has been to develop a LSS control methodology that produces designs that meet strenuous performance requirements and are robust to model inaccuracies. Unfortunately, performance and robustness are conflicting requirements. Because LSS's can not be fully tested on ground, it has become an accepted fact that the design of LSS control systems to meet performance requirements can not be completed until the LSS is placed on-orbit and tested and an accurate model is extracted from on-orbit test results. Modern MIMO sampled-data frequency response design techniques are viable candidates for designing LSS control systems. First, this paper presents techniques for performing MIMO system identification (ID) from test data. Then, techniques for improving the performance of the system ID process in the presence of noise are presented. Finally, practical utility of the system ID approaches are validated by the presentation of results obtained from application on the LSS Ground Test Facility at Marshall Space Flight Center.

Mitchell, Jerrel R.↗
NASA NTRS1972

A method for the measurement and analysis of ride vibrations of transportation systems

The measurement and recording of ride vibrations which affect passenger comfort in transportation systems and the subsequent data-reduction methods necessary for interpreting the data present exceptional instrumentation requirements and necessitate the use of computers for specialized analysis techniques. A method is presented for both measuring and analyzing ride vibrations of the type encountered in ground and air transportation systems. A portable system for measuring and recording low-frequency, low-amplitude accelerations and specialized data-reduction procedures are described. Sample vibration measurements in the form of statistical parameters representative of typical transportation systems are also presented to demonstrate the utility of the techniques.

Catherines, J. J.↗
DOE OSTI2024

Human Host Cellular Response to HCoV-229E Infection Transcriptomics (ACS-DP1)

The purpose of this experiment was to evaluate the human host cellular response to wild-type Human coronavirus strain 229E (HCoV-229E) infection. Sample data was obtained for mock and infected immortalized human lung epithelial cells (A549) (MOI 5), immortalized human lung fibroblasts cells (MRC5) (MOI5), and primary human airway epithelial (HAE) (MOI 3) cells from lung tissue. Sample data was acquired using an Illumina HiSeq 2000 sequencer system and processed for RNA sequencing (RNA-Seq) expression analysis.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1976

Chemical vapor deposition growth

A chemical vapor deposition (CVD) reactor system with a vertical deposition chamber was used for the growth of Si films on glass, glass-ceramic, and polycrystalline ceramic substrates. Silicon vapor was produced by pyrolysis of SiH4 in a H2 or He carrier gas. Preliminary deposition experiments with two of the available glasses were not encouraging. Moderately encouraging results, however, were obtained with fired polycrystalline alumina substrates, which were used for Si deposition at temperatures above 1,000 C. The surfaces of both the substrates and the films were characterized by X-ray diffraction, reflection electron diffraction, scanning electron microscopy optical microscopy, and surface profilometric techniques. Several experiments were conducted to establish baseline performance data for the reactor system, including temperature distributions on the sample pedestal, effects of carrier gas flow rate on temperature and film thickness, and Si film growth rate as a function of temperature.

Ruth, R. P.↗
NASA NTRS1979

Airborne atmospheric sampling system

The atmospheric sampling system developed for use on board commercial airliners as part of the Global Atmospheric Sampling Program (GASP) is described. The automated air-constituent measuring system is installed in a Boeing 747 airliner below the passenger cabin floor near the nose wheel well. It consists of an air sample flow system, composed of air inlet and pressurization systems, computerized data acquisition and system control units which direct system operation in 15 modes, and commercial instruments significantly modified to measure low levels of atmospheric constituents (ozone, water vapor, nitrogen oxides, carbon monoxide, chlorofluoromethanes, particulates, condensation nuclei, sulfates and nitrates). Flight and meteorological data, including air temperature and altitude, are also recorded. The system is designed for servicing at 14-day intervals, and to require a minimum of aircrew involvement.

Gustafsson, U. R. C.↗
NASA NTRS1989

Sampling characteristics of satellite orbits

The irregular space-time sampling of any finite region by an orbiting satellite raises difficult questions as to which frequencies and wavenumbers can be determined and which will alias into others. Conventional sampling theorems must be extended to account for both irregular data distributions and observational noise - the sampling irregularity making the system much more susceptible to noise than in regularly sampled cases. The problem is formulated here in terms of least-squares and applied to spacecraft in 10-day and 17-day repeating orbits. The 'diamond-pattern' laid down spatially in such repeating orbits means that either repeat period adequately samples the spatial variables, but the slow overall temporal coverage in the 17-day pattern leads to much greater uncertainty than in the shorter repeat cycle. The result is not definitive and it is not concluded that a 10-day orbit repeat is the most appropriate one. A major conclusion, however, is that different orbital choices have potentially quite different sampling characteristics which need to be analyzed in terms of the spectral characteristics of the moving sea surface.

Wunsch, Carl↗