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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 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

SELKIE Spectral Extraction Results

This document describes results from the WAMOR Chesapeake Bay collection in October 2024, a data collection from the Arkeus HSOR hyperspectral sensor. The calibration array was staged at USCG Station Little Creek, Virginia. With the provided HSOR imagery and data, our analysis does not show a capability to effectively detect materials of interest from non-materials of interest as well as differentiate materials of interest from each other, the materials of interest being polypropylene, polyester, and cotton. The fundamental reasons are (1) the spectral bands of HSOR do not reside in specific wavelength locations to allow for material identification and (2) the provided imagery appears to not have consistent band-to-band relationships indicative of a lack of calibration (gain/offsets) or some other calibration issues. With regard to analyzing a subset of the delivered HSOR, HSOR can make general statements about materials not being water and have the capability to make color assessments.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Movable Thermometer System in ProtoDUNE

The movable temperature profiler is a 7 m vertical array of 24 sensors that measures cryogenic temperatures with a precision of a few mK. This precision is necessary to monitor the efficiency of re-circulation and purification of liquid-argon inside large liquid-argon based neutrino detectors. Liquid argon temperature impacts electron (signal) drift velocity, flow, purity distribution and thus the overall energy calibration. The temperature profiler is motorized and moves vertically, while in the detector, and cross-calibrates neighboring sensors. The temperature offsets between each sensor cancel the effects of electromagnetic noise. This poster reports on the temperature measurements and such in-situ cross-calibrations at ProtoDUNE (single phase) at CERN.}

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

Local Explosion Detection and Infrasound Localization by Reverse Time Migration Using 3-D Finite-Difference Wave Propagation

Infrasound data are routinely used to detect and locate volcanic and other explosions, using both arrays and single sensor networks. However, at local distances (< km) topography often complicates acoustic propagation, resulting in inaccurate acoustic travel times leading to biased source locations when assuming straight-line propagation. Here we present a new method, termed Reverse Time Migration-Finite-Difference Time Domain (RTM-FDTD), that integrates numerical modeling into the standard RTM back-projection process. Travel time information is computed across the entire potential source grid via FDTD modeling to incorporate the effects of topography. The waveforms are then back-projected and stacked at each grid point, with the stack maximum corresponding to the likely source. We apply our method to three volcanoes with different network configurations, source-receiver distances, and topography. At Yasur Volcano, Vanuatu, RTM-FDTD locates explosions within ~20 m of the source and differentiates between multiple vents. RTM-FDTD produces a more accurate location for the two Yasur subcraters than standard RTM and doubles the number of detected events. At Sakurajima Volcano, Japan, RTM-FDTD locates the source within 50 m of the active vent despite notable topographic blocking. The RTM-FDTD location is similar to that from the Time Reversal Mirror method, but is more computationally efficient. Lastly, at Shishaldin Volcano, Alaska, RTM and RTM-FDTD both produce realistic source locations (<50 m) for ground-coupled airwaves recorded on a four-station seismic network. We show that RTM is an effective method to detect and locate infrasonic sources across a variety of scenarios, and by integrating numerical modeling, RTM-FDTD produces more accurate source locations and increases the detection capability.

58 GEOSCIENCES↗
NASA NTRS1981

The hot plasma environment and floating potentials of an electron-beam-emitting rocket in the ionosphere

The plasma environment surrounding the Echo III accelerator payload is examined with an extensive array of particle sensors. Suprathermal electrons are produced isotropically around the payload during the gun firings and decay away in approximately 32 ms. The largest directional intensities of this component are observed at the higher altitudes. Quick echo electrons are also observed to produce suprathermal electrons when they encounter the payload. The hot electrons surrounding the accelerator payload during gun injections bring sufficient charge to the payload to neutralize it provided the loss of charge by secondary production on the payload skin is small. Since the hot population exists for tens of milliseconds after the gun turnoff, it results in driving the payload up to 4 volts negative during this time. Quick echo electrons creating suprathermal electrons around the payload also drive the payload to a few volts negative.

Arnoldy, R. L.↗
NASA NTRS1983

Scanning seismic intrusion detection method and apparatus

An intrusion monitoring system includes an array of seismic sensors, such as geophones, arranged along a perimeter to be monitored for unauthorized intrusion as by surface movement or tunneling. Two wires lead from each sensor to a central monitoring station. The central monitoring station has three modes of operation. In a first mode of operation, the output of all of the seismic sensors is summed into a receiver for amplification and detection. When the amplitude of the summed signals exceeds a certain predetermined threshold value an alarm is sounded. In a second mode of operation, the individual output signals from the sensors are multiplexed into the receiver for sequentially interrogating each of the sensors.

Lee, R. D.↗
NASA NTRS1983

Optical fiber tactile sensor

A tactile sensor comprises an array of cells which are covered by an elastic membrane, having an exposed surface which is adapted to come in contact with an object. Light is conducted to each cell from a light source by an optical fiber which terminates at the cell. Reflected light from the cell is conducted by an optical fiber to a light processor, which senses changes in the light received thereby from an ambient level whenever an object comes in contact with the membrane surface above the cell.

Bejczy, A. K.↗
NASA NTRS1982

Multispectral linear array

The Multispectral Linear Array (MLA) is a solid-state earth imagery radiometer operating in the 'push-broom' mode and using a focal plane containing multiple spectral band linear detector arrays. The MLA sensor offers the capability for increased spatial and spectral resolution with multiple selectable bands and in-orbit operation flexibility. Both free-flyer (satellite) and Shuttle-attached instrument designs have been studied. Four Shuttle-attached MLA instrument design studies were initiated in 1982, and the concepts resulting from these studies are described.

Richard, H. L.↗
NASA NTRS1982

Imaging Science Panel. Multispectral Imaging Science Working Group joint meeting with Information Science Panel: Introduction

The state-of-the-art of multispectral sensing is reviewed and recommendations for future research and development are proposed. specifically, two generic sensor concepts were discussed. One is the multispectral pushbroom sensor utilizing linear array technology which operates in six spectral bands including two in the SWIR region and incorporates capabilities for stereo and crosstrack pointing. The second concept is the imaging spectrometer (IS) which incorporates a dispersive element and area arrays to provide both spectral and spatial information simultaneously. Other key technology areas included very large scale integration and the computer aided design of these devices.

Source record↗
NASA NTRS1984

Design of infrasound-detection system via adaptive LMSTDE algorithm

A proposed solution to an aviation safety problem is based on passive detection of turbulent weather phenomena through their infrasonic emission. This thesis describes a system design that is adequate for detection and bearing evaluation of infrasounds. An array of four sensors, with the appropriate hardware, is used for the detection part. Bearing evaluation is based on estimates of time delays between sensor outputs. The generalized cross correlation (GCC), as the conventional time-delay estimation (TDE) method, is first reviewed. An adaptive TDE approach, using the least mean square (LMS) algorithm, is then discussed. A comparison between the two techniques is made and the advantages of the adaptive approach are listed. The behavior of the GCC, as a Roth processor, is examined for the anticipated signals. It is shown that the Roth processor has the desired effect of sharpening the peak of the correlation function. It is also shown that the LMSTDE technique is an equivalent implementation of the Roth processor in the time domain. A LMSTDE lead-lag model, with a variable stability coefficient and a convergence criterion, is designed.

Khalaf, C. S.↗
NASA NTRS1985

The Earth Observing System - A multidisciplinary system for the long-term acquisition of earth science data from space

The development of the Earth Observing System (EOS) requirements is examined. An envisioned, EOS is to be NASA's multidisciplinary approach to acquisition of earth science data in the 1990s. The rationale and assumptions for the EOS are presented, together with a discussion of anticipated operations and use environments. Planned instrumentation concepts are discussed, involving a broad array of multiuse sensors operating across the electromagnetic spectrum from the ultraviolet to the microwave and including both active and passive techniques. Concepts for the near-polar orbiting observatory system, and essentially permanent man-serviced and -tended facility, are presented, along with concepts for information capture, processing and distribution and for common data-base referencing of acquired data. Milestones are indicated that are to be passed before a commitment to program execution can be made later in this decade.

Broome, D. R., Jr.↗
NASA NTRS1986

Balloon gondola diagnostics package

In order to define a new gondola structural specification and to quantify the balloon termination environment, NASA developed a balloon gondola diagnostics package (GDP). This addition to the balloon flight train is comprised of a large array of electronic sensors employed to define the forces and accelerations imposed on a gondola during the termination event. These sensors include the following: a load cell, a three-axis accelerometer, two three-axis rate gyros, two magnetometers, and a two axis inclinometer. A transceiver couple allows the data to be telemetered across any in-line rotator to the gondola-mounted memory system. The GDP is commanded 'ON' just prior to parachute deployment in order to record the entire event.

Cantor, K. M.↗
NASA NTRS1988

Synchronous Photodiode-Signal Sampler

Synchronous sampling circuit increases signal-to-noise ratio of measurements of chopped signal of known phase and frequency in presence of low-frequency or dc background noise. Used with linear array of photoelectric sensors for locating edge of metal plate. Multiplexing circuit cycles through 16 light-emitting-diode/photodiode pairs, under computer control. Synchronized with multiplexer so edge detector makes one background-subtracted signal measurement per emitter/detector pair in turn.

Primus, Howard K.↗
NASA NTRS1988

Feasibility of an uncooled imaging spectrometer for the exploration of the solar system

A state-of-the-art imaging spectrometer concept is presented for visible-midwavelength IR spectral region studies of the solar system that obviates the until-now essential use of cryogenic cooling. This uncooled imaging spectrometer configuration is evaluated in view of the prospective environments of the instrument in various spacecraft orbits, as well as in light of various available photodetector materials and sensor focal plane array configurations.

Liaw, H. M.↗
NASA NTRS1993

Monitoring Loads In Fiber-Reinforced Composite Materials

In new method of determining load on specimen, direction of stress wave propagation measured by array of acoustic sensors attached to specimen. Responses of sensors analyzed by strain-energy-density calculations to calculate load. Change in anisotropy of elasticity caused by applied load and corresponding induced strain. Is means to monitor applied load corresponding to measurable shift in direction of propagation of stress wave. Monitoring device based on this method made integral part of airframe in which unidirectional section of structure, such as spar cap or longeron, carries primary load.

Prosser, William H.↗
NASA NTRS2004

Optimization of X-ray Absorbers for TES Microcalorimeters

We have investigated the thermal, electrical, and structural properties of Bi and BiCu films that are being developed as X-ray absorbers for transition-edge sensor (TES) microcalorimeter arrays for imaging X-ray spectroscopy. Bi could be an ideal material for an X-ray absorber due to its high X-ray stopping power and low heat capacity, but it has a low thermal conductivity, which can result in position dependence of the pulses in the absorber. In order to improve the thermal conductivity, we added Cu layers in between the Bi layers. We measured electrical and thermal conductivities of the films around 0.1 K(sub 1) the operating temperature of the TES calorimeter, to examine the films and to determine the optimal thickness of the Cu layer. From the electrical conductivity measurements, we found that the Cu is more resistive on the Bi than on a Si substrate. Together with an SEM picture of the Bi surface, we concluded that the rough surface of the Bi film makes the Cu layer resistive when the Cu layer is not thick enough t o fill in the roughness. From the thermal conductivity measurements, we determined the thermal diffusion constant to be 2 x l0(exp 3) micrometers squared per microsecond in a film that consists of 2.25 micrometers of Bi and 0.1 micrometers of Cu. We measured the position dependence in the film and found that its thermal diffusion constant is too low to get good energy resolution, because of the resistive Cu layer and/or possibly a very high heat capacity of our Bi films. We show plans to improve the thermal diffusion constant in our BiCu absorbers.

Iyomoto, Naoko↗
NASA NTRS1997

Real-Time Sensor Validation System Developed for Reusable Launch Vehicle Testbed

A real-time system for validating sensor health has been developed for the reusable launch vehicle (RLV) program. This system, which is part of the propulsion checkout and control system (PCCS), was designed for use in an integrated propulsion technology demonstrator testbed built by Rockwell International and located at the NASA Marshall Space Flight Center. Work on the sensor health validation system, a result of an industry-NASA partnership, was completed at the NASA Lewis Research Center, then delivered to Marshall for integration and testing. The sensor validation software performs three basic functions: it identifies failed sensors, it provides reconstructed signals for failed sensors, and it identifies off-nominal system transient behavior that cannot be attributed to a failed sensor. The code is initiated by host software before the start of a propulsion system test, and it is called by the host program every control cycle. The output is posted to global memory for use by other PCCS modules. Output includes a list indicating the status of each sensor (i.e., failed, healthy, or reconstructed) and a list of features that are not due to a sensor failure. If a sensor failure is found, the system modifies that sensor's data array by substituting a reconstructed signal, when possible, for use by other PCCS modules.

Jankovsky, Amy L.↗
NASA NTRS2002

E-tongue 2 REDOX response to heavy metals

E-Tongue 2 an array of electrochemical sensors including REDOX electrodes for Cylic Voltammetry and Anodic Stripping Voltammetry measurements, Galvanic cells for corrosion measurements, and Ion Selective Electrodes.

electromechanical sensors↗
NASA NTRS2006

Processing of Mars Exploration Rover Imagery for Science and Operations Planning

The twin Mars Exploration Rovers (MER) delivered an unprecedented array of image sensors to the Mars surface. These cameras were essential for operations, science, and public engagement. The Multimission Image Processing Laboratory (MIPL) at the Jet Propulsion Laboratory was responsible for the first-order processing of all of the images returned by these cameras. This processing included reconstruction of the original images, systematic and ad hoc generation of a wide variety of products derived from those images, and delivery of the data to a variety of customers, within tight time constraints. A combination of automated and manual processes was developed to meet these requirements, with significant inheritance from prior missions. This paper describes the image products generated by MIPL for MER and the processes used to produce and deliver them.

Instruments↗