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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Release of volatiles from possible Martian analogs

Viking data suggest the presence of volatile-rich materials in the Martian regolith. The thermal stabilities of mineral phases and their volatile release profiles were studied in detail in our laboratory. Thermal analysis, combined with mass spectrometry, was applied to the study of the behavior of carbonates, sulfates, hydrates, and clays. The results indicate that these techniques are useful in the preliminary mineralogical characterizations of volatile-rich minerals. However, our results also indicate that great care must be taken in the incorporation into planetary probes of such methods as hearing rates, pressure, composition of atmospheres, grain size, etc., because these factors effect volatile release.

Kotra, R. K.↗
NASA NTRS2012

System and method for cognitive processing for data fusion

A system and method for cognitive processing of sensor data. A processor array receiving analog sensor data and having programmable interconnects, multiplication weights, and filters provides for adaptive learning in real-time. A static random access memory contains the programmable data for the processor array and the stored data is modified to provide for adaptive learning.

Duong, Tuan A.↗
NASA NTRS1977

Charge-coupled device data processor for an airborne imaging radar system

Processing of raw analog echo data from synthetic aperture radar receiver into images on board an airborne radar platform is discussed. Processing is made feasible by utilizing charge-coupled devices (CCD). CCD circuits are utilized to perform input sampling, presumming, range correlation and azimuth correlation in the analog domain. These radar data processing functions are implemented for single-look or multiple-look imaging radar systems.

Arens, W. E.↗
NASA NTRSDate not supplied

Nearest-Neighbor Machine Learning Feature Selection for Interpretation of Microbial Molecular Signatures from Isotope Ratio Mass Spectrometry Data

Mass spectrometry (MS) promises to be a powerful tool for potential biosignature detection during astrobiological missions on ocean worlds in our solar system. Accurate and generalizable machine learning methods could enhance science return on investment by predicting seawater chemistry and classifying isotopic biosignatures, either as a signature consistent with microbial life (biotic) or as a novelty (unclassified/unique). However, machine learning models are likely to be complex and involve interactions between MS features, making biosignatures difficult to interpret. Feature selection methods provide biological and chemical context that help interpret the mechanisms of machine learning models, but these methods also need the ability to detect complex interactions. Previously, we developed a machine learning feature selection algorithm called nearest-neighbor projected distance regression (NPDR) that has the ability to identify important model features that involve complex interactions and automatically reduce correlation and the dimensionality in a high-dimensional variable space. The standard distance metrics used in NPDR – Manhattan and Euclidean – assume the multivariate data are isotropic, which is often violated in real data due to differences in the covariance between variables. Thus, we extend NPDR to include a random forest distance, and other anisotropic distance metrics, for computing nearest neighbors. We also augment the isotope-ratio MS data with time-series features from the raw MS signal to improve biotic classification. We test NPDR on our novel experimental ocean world seawater analog MS data. We measure isotope fractionations of volatile CO 2 that could be measured in exospheres or plumes. Samples include baseline abiotic conditions using a range of possible seawater chemistry consistent with Europa and Enceladus, and biotic samples that include microbes in these seawaters. We use penalized NPDR with random forest proximity to identify interpretable microbial molecular signatures. We compare features with random forest importance, and we train a classifier that discriminates between biotic and abiotic samples with high accuracy. These ML-trained ocean-world analog MS data could be used to assist in identifying biosignatures during future missions.

geochemistry↗
NASA NTRS1989

High-speed digital fiber optic links for satellite traffic

Large aperture phased array antennas operating at millimeter wave frequencies are designed for space-based communications and imaging platforms. Array elements are comprised of active T/R modules which are linked to the central processing unit through high-speed fiber-optic networks. The system architecture satisfying system requirements at millimeter wave frequency is T/R level data mixing where data and frequency reference signals are distributed independently before mixing at the T/R modules. This paper demonstrates design procedures of a low loss high-speed fiber-optic link used for transmission of data signals over 600-900 MHz bandwidth inside satellite. The fiber-optic link is characterized for transmission of analog and digital data. A dynamic range of 79 dB/MHz was measured for analog data over the bandwidth. On the other hand, for bursted SMSK satellite traffic at 220 Mbps rates, BER of 2 x 10 to the -7th was measured for E(b)/N(o) of 14.3 dB.

Daryoush, A. S.↗
NASA NTRS1993

Techniques for transmitting digital data on the Spacelab's analog video channel

A study was made of various techniques for transmitting digital data over a composite video channel. Transmitting data from experiments on the Space Shuttle Orbiter over a video channel is attractive since extra channel capacity is needed. Broadcast television telecommunications schemes and other techniques described in the literature were reviewed and compared. PSK (Phase Shift Keying), MPSK (m-ary PSK), or PAM (Pulse Amplitude Modulation) can be transmitted on visible lines of a frame, unassigned lines of the VBI (Vertical Blanking Interval), or during the HBI (Horizontal Blanking Interval). All three modulation techniques can be attractive under the proper conditions. However, PAM on visible lines or during the VBI should be relatively easy to implement, provide adequate average data rates, and give acceptable BERs (Bit Error Rates).

Smith, Dean L.↗
NASA NTRS1988

Computer Interface For A Spectroreflectometer

FORTRAN program controls stepping motors and signal-processing electronics via S-100 computer bus. Group of spectroreflectometers modified to provide computer-controlled operation and data collection. Analog and digital signal-processing circuits enable use of computerized automatic data collection and analysis. Previously, spectroreflectometer data recorded on strip charts.

Hurd, William A.↗
NASA NTRS1969

Biomedical bulk data processing program

Analog-to-digital computer accepts physiological flight data as three basic analog input signals - the ECG signal, the flowmeter signal which is a respiration monitor, and the accelerometer signal which measures the normal-g-load on the subject.

Source record↗
NASA NTRS2012

Investigations Using Laboratory Testbeds to Interpret Flight Instrument Datasets from Mars Robotic Missions

The Astromaterials Research and Exploration Science Directorate at the NASA Johnson Space Center (JSC) has laboratory instrumentation that mimic the capabilities of corresponding flight instruments to enable interpretation of datasets returned from Mars robotic missions. The lab instruments have been and continue to be applied to datasets for the Moessbauer Spectrometer (MB) on the Mars Exploration Rovers (MER), the Thermal & Evolved Gas Analyzer (TEGA) on the Mars Phoenix Scout, the CRISM instrument on the Mars Reconnaissance Orbiter Missions and will be applied to datasets for the Sample Analysis at Mars (SAM), Chemistry and Mineralogy (CheMin) and Chemistry & Camera (ChemCam) instruments onboard the Mars Science Laboratory (MSL). The laboratory instruments can analyze analog samples at costs that are substantially lower than engineering models of flight instruments, but their success to enable interpretation of flight data depends on how closely their capabilities mimic those of the flight instrument. The JSC lab MB instruments are equivalent to the MER instruments except without flight qualified components and no reference channel Co-57 source. Data from analog samples were critical for identification of Mg-Fe carbonate at Gusev crater. Fiber-optic VNIR spectrometers are used to obtain CRISM-like spectral data over the range 350-2500 nm, and data for Fephyllosilicates show irreversible behavior in the electronic transition region upon dessication. The MB and VNIR instruments can be operated within chambers where, for example, the absolute H2O concentration can be measured and controlled. Phoenix's TEGA consisted of a calorimeter coupled to a mass spectrometer (MS). The JSC laboratory testbed instrument consisted of a differential scanning calorimeter (DSC) coupled to a MS configured to operate under total pressure (12 mbar), heating rate (20 C/min), and purge gas composition (N2) analogous to the flight TEGA. TEGA detected CO2 release at both low (400-680 C) and high (725-820 C) temperature and an endothermic reaction in concert with the high temperature release. The high-temperature thermal decomposition is consistent with calcite, dolomite, or ankerite, (3-6 wt.%) or any combination of these phase based upon laboratory testbed experiments. Recent laboratory experiments suggest that the low temperature CO2 release was caused by a reaction between calcium carbonate and hydrated magnesium perchlorate; although, CO2 release by the oxidation of organic materials and Fe-/Mg-rich carbonates cannot be ruled out. MSL landed in Gale crater on August 5, 2012. Although numerous analog samples have been analyzed on the JSC laboratory testbeds, no SAM, CheMin, or ChemCam analyses have been acquired by MSL to date. The JSC SAM laboratory testbed consists of a thermal analyzer coupled with a MS configured to operate under total pressure (30 mbar), heating rate (35 C/min), and purge gas composition (He) analogous to the flight SAM. The CheMin and ChemCam laboratory testbeds were developed and built by inXitu, Inc. and Los Alamos National Laboratory, respectively, to acquire datasets relevant to the MSL CheMin and ChemCam flight instruments.

Ming, D. W.↗
NASA NTRS1992

Heterojunction bipolar transistor technology for data acquisition and communication

Heterojunction Bipolar Transistor (HBT) technology has emerged as one of the most promising technologies for ultrahigh-speed integrated circuits. HBT circuits for digital and analog applications, data conversion, and power amplification have been realized, with speed performance well above 20 GHz. At Rockwell, a baseline AlGaAs/GaAs HBT technology has been established in a manufacturing facility. This paper describes the HBT technology, transistor characteristics, and HBT circuits for data acquisition and communication.

Wang, C.↗
NASA NTRS1984

Modulated beam injection from the Space Shuttle during magnetic conjunctions of STS 3 with the DE 1 satellite

An electron beam emitted from the Office of Space Sciences 1 pallet on STS 3 was pulsed with specially designed very low frequency (VLF) formats in an attempt to generate whistler mode waves. Modulated operations of the beam emitted by a fast pulse electron generator (FPEG) were initiated during times of magnetic conjunctions between STS 3 and the high-altitude DE 1 satellite equipped with broadband VLF receivers. Coordinated FPEG/VLF modulation and DE 1 wideband data acquisition were achieved in 12 different cases. No evidence of any waves generated by FPEG were detected on the DE 1 analog wideband data. However, it is shown that in all of the cases, either the STS 3 attitude was such that the emitted electrons struck the main body of the vehicle, or it was not possible for whistler mode waves to propagate from the STS 3 location up to the vicinity of the DE 1 satellite.

Inan, U. S.↗
NASA NTRS2017

Advanced Wireless Sensor Nodes - MSFC

NASA field center Marshall Space Flight Center (Huntsville, AL), has invested in advanced wireless sensor technology development. Developments for a wireless microcontroller back-end were primarily focused on the commercial Synapse Wireless family of devices. These devices have many useful features for NASA applications, good characteristics and the ability to be programmed Over-The-Air (OTA). The effort has focused on two widely used sensor types, mechanical strain gauges and thermal sensors. Mechanical strain gauges are used extensively in NASA structural testing and even on vehicle instrumentation systems. Additionally, thermal monitoring with many types of sensors is extensively used. These thermal sensors include thermocouples of all types, resistive temperature devices (RTDs), diodes and other thermal sensor types. The wireless thermal board will accommodate all of these types of sensor inputs to an analog front end. The analog front end on each of the sensors interfaces to the Synapse wireless microcontroller, based on the Atmel Atmega128 device. Once the analog sensor output data is digitized by the onboard analog to digital converter (A/D), the data is available for analysis, computation or transmission. Various hardware features allow custom embedded software to manage battery power to enhance battery life. This technology development fits nicely into using numerous additional sensor front ends, including some of the low-cost printed circuit board capacitive moisture content sensors currently being developed at Auburn University.

Varnavas, Kosta↗
NASA NTRS2017

IMAPS Device Packaging Conference 2017 - Engineered Micro Systems & Devices Track

NASA field center Marshall Space Flight Center (Huntsville, AL), has invested in advanced wireless sensor technology development. Developments for a wireless microcontroller back-end were primarily focused on the commercial Synapse Wireless family of devices. These devices have many useful features for NASA applications, good characteristics and the ability to be programmed Over-The-Air (OTA). The effort has focused on two widely used sensor types, mechanical strain gauges and thermal sensors. Mechanical strain gauges are used extensively in NASA structural testing and even on vehicle instrumentation systems. Additionally, thermal monitoring with many types of sensors is extensively used. These thermal sensors include thermocouples of all types, resistive temperature devices (RTDs), diodes and other thermal sensor types. The wireless thermal board will accommodate all of these types of sensor inputs to an analog front end. The analog front end on each of the sensors interfaces to the Synapse wireless microcontroller, based on the Atmel Atmega128 device. Once the analog sensor output data is digitized by the onboard analog to digital converter (A/D), the data is available for analysis, computation or transmission. Various hardware features allow custom embedded software to manage battery power to enhance battery life. This technology development fits nicely into using numerous additional sensor front ends, including some of the low-cost printed circuit board capacitive moisture content sensors currently being developed at Auburn University.

Varnavas, Kosta↗
NASA NTRS1970

Digital input is buffered to real-time analog display

Buffering technique utilizes nine-bit binary counter and holding register of eight flip-flops. These flip-flops form the memory device that allows precise asynchronous conversion of the digital source data. Counter generates a waveform which is passed through a low pass filter to recover data in analog form.

Bower, K. F.↗
NASA NTRS1979

Digital and analog communication systems

The book presents an introductory treatment of digital and analog communication systems with emphasis on digital systems. Attention is given to the following topics: systems and signal analysis, random signal theory, information and channel capacity, baseband data transmission, analog signal transmission, noise in analog communication systems, digital carrier modulation schemes, error control coding, and the digital transmission of analog signals.

Shanmugam, K. S.↗