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At least 541 records · Page 30
All sourcesNASA NTRSDOE OSTI
NASA NTRS2015

Characterizing Debris in the Infrared with UKIRT

The United Kingdom Infrared Telescope (UKIRT) has been a major asset for the NASA Orbital Debris Program Office (OPDO) since March, 2014. With the UKIRT current contract coming to an end at the finish of FY15, there is a golden opportunity for this community to fund and gain access to UKIRT as an SSA asset through HCAR (Hawaii Center for Astronautics Research). UKIRT is the only telescope on Mauna Kea dedicated to infrared bands. Spectral coverage ranges from the near- (0.8-5μm) to the mid- to far-infrared (8-25 micrometer) regime. To date, debris observations have been collected with three instruments. Near-Infrared photometry with ZYJHK filters has been obtained with the Wide Field Camera (WFCam). Near-Infrared (1-2.5 micrometer) spectra are the focus of observations taken with the UKIRT Imager SpecTrometer (UIST). And Michelle (Mid Infrared escCHELLE) is a thermal imager-spectrometer designed for the 8-25 micrometer regime. With 35% of the telescope time allocated to ODPO, a very steady stream of data has been collected on a variety of debris targets using all the above instrumentation. Initial results from WFCam were discussed at AMOS and NISOI including analyses on IDCSPs, the MSG cooler and baffle covers. The cylindrical HS-376 buses were the focus of recent WFCam runs. Summary analyses of these works will be presented. Focus will be given to initial results of the data collected with the Cassegrain instruments, UIST and Michelle. UIST spectra were collected in September 2014, March and April 2015. Targets included a suite of HS-376 buses, well suited to investigate the signatures of blue solar panels; several dead satellites with solar array wings; Titan 3C transtage debris; the CTA Array cover, and others. In addition, Michelle mid-IR photometry was collected on a select few objects during the April 2015 run. Using WFCam, UIST and Michelle the Lockheed Martin has been observing operational satellites in the near- mid and far-infrared regime in an attempt to understand the health and status of several satellites that are based on the Lockheed Martin A2100 bus. The potential insights into debris characterization using this range of assets, and early analyses will be discussed, as well as the opportunities possible for utilizing UKIRT as an SSA asset.

Lederer, S. M.↗
NASA NTRS2019

No Clear, Direct Evidence for Multiple Protoplanets Orbiting LkCa 15: LkCa 15 bcd are Likely Inner Disk Signals

Two studies utilizing sparse aperture-masking (SAM) interferometry and Hα differential imaging have reported multiple Jovian companions around the young solar-mass star, LkCa 15 (LkCa 15 bcd): thefirst claimed direct detection of infant, newly formed planets (“protoplanets”). We present new near-infrared direct imaging/spectroscopy from the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system coupled with Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS) integral field spectrograph and multi-epoch thermal infrared imaging from Keck/ NIRC2 of LkCa 15 at high Strehl ratios. These data provide the first direct imaging look at the same wavelengths and in the same locations where previous studies identified the LkCa 15 protoplanets,and thus offer the first decisive test of their existence.The data do not reveal these planets. Instead,we resolve extended emission tracing adust disk with a brightness and location comparable to that claimed for LkCa 15 bcd. Forward-models attributing this signal to orbiting planets are inconsistent with the combined SCExAO/CHARIS and Keck/NIRC2 data. An inner disk provides a more compelling explanation for the SAM detections and perhaps also the claimed Hα detection of LkCa 15 b. We conclude that there is currently no clear, direct evidence for multiple protoplanets orbiting LkCa 15, although the system likely contains at least one unseen Jovian companion. To identify Jovian companions around LkCa 15 from future observations, the inner disk should be detected and its effect modeled, removed, and shown to be distinguishable from planets. Protoplanet candidates identified from similar systems should likewise be clearly distinguished from disk emission through modeling.

Thayne Currie↗
NASA NTRS1986

Enhancement of time images for photointerpretation

The Thermal Infrared Multispectral Scanner (TIMS) images consist of six channels of data acquired in bands between 8 and 12 microns, thus they contain information about both temperature and emittance. Scene temperatures are controlled by reflectivity of the surface, but also by its geometry with respect to the Sun, time of day, and other factors unrelated to composition. Emittance is dependent upon composition alone. Thus the photointerpreter may wish to enhance emittance information selectively. Because thermal emittances in real scenes vary but little, image data tend to be highly correlated along channels. Special image processing is required to make this information available for the photointerpreter. Processing includes noise removal, construction of model emittance images, and construction of false-color pictures enhanced by decorrelation techniques.

Gillespie, A. R.↗
NASA NTRS2010

Air-coupled acoustic thermography for in-situ evaluation

Acoustic thermography uses a housing configured for thermal, acoustic and infrared radiation shielding. For in-situ applications, the housing has an open side adapted to be sealingly coupled to a surface region of a structure such that an enclosed chamber filled with air is defined. One or more acoustic sources are positioned to direct acoustic waves through the air in the enclosed chamber and towards the surface region. To activate and control each acoustic source, a pulsed signal is applied thereto. An infrared imager focused on the surface region detects a thermal image of the surface region. A data capture device records the thermal image in synchronicity with each pulse of the pulsed signal such that a time series of thermal images is generated. For enhanced sensitivity and/or repeatability, sound and/or vibrations at the surface region can be used in feedback control of the pulsed signal applied to the acoustic sources.

Zalameda, Joseph N.↗
DOE OSTI2022

Processing of phase change materials by fused deposition modeling: Toward efficient thermal energy storage designs

We report that recently, several efforts have emerged that employ additive manufacturing techniques to integrate phase change material (PCM) thermal energy storage into geometrically complex designs for advanced thermal management. In this work, we contribute to this emerging research by reporting on the production of a composite nylon-based filament for fused deposition modeling incorporating encapsulated PCMs for 3D printing heat sink geometries. Microencapsulated PCM (MEPCM) with a 6 degrees C transition temperature was selected as the material for thermal energy storage. This transition temperature was selected due to its suitability to provide thermal energy storage to target air-conditioning applications in buildings. In an attempt to improve the thermal conductivity of the composite, fine boron nitride fillers were added, although the effect on improvement was found to be negligible in the overall composite mixture. The nylon-MEPCM ratio in the filaments was optimized, and filaments containing up to 40 wt% MEPCM were successfully synthesized, which were found optimal for 3D printing complex heat sink and other geometries. Thermal and mechanical properties of the filaments were characterized, including latent heat of fusion, thermal conductivity, phase change temperature, tensile strength, and more. Thermal infrared imaging of heat sink geometries printed using the MEPCM filaments undergoing thermal discharging was also conducted. This work presents the most promising result to date in the open literature for a 3D-printed PCM composite in the combination of size, energy density, and geometric complexity of printed parts.

25 ENERGY STORAGE↗
NASA NTRS1991

Thermal analysis of the ultraviolet imager camera and electronics

The Ultraviolet Imaging experiment has undergone design changes that necessiate updating the reduced thermal models (RTM's) for both the Camera and Electronics. In addition, there are several mission scenarios that need to be evaluated in terms of thermal response of the instruments. The impact of these design changes and mission scenarios on the thermal performance of the Camera and Electronics assemblies is discussed.

Dirks, Gregory J.↗
NASA NTRS1992

Rapid detection and quantification of impact damage in composite structures

It is shown that a multidisciplinary nondestructive evaluation approach for impact damage detection in composite structures can be used to produce a more efficient inspection. The multidisciplinary NDE approach relies on fast large area thermographic inspections along with detailed ultrasonic volumetric imaging. The thermal inspection technique rapidly identifies the impact damage. The ultrasonic volumetric imaging quantifies the impact generated delaminations through the volume of the structure.

Smith, Barry T.↗
NASA NTRS2003

Pristine Impact Crater Populations of Mars

This study focused on obtaining size frequency distributions of pristine crater populations from various terrains of Mars. Images from the Viking Orbiter (VO), Mars Orbital Camera (MOC), and Thermal Emission Imaging System (THEMIS) were utilized for this study. The results may aid in providing information about crater production functions and resurfacing events on Mars.

Chauhan, R. V.↗
NASA NTRS2004

Impact Crater Abundance of the Martian South Polar Layered Deposits from THEMIS Visible Imaging

The polar layered deposits (PLD) of Mars have attracted considerable attention since their identification in Mariner 9 images, largely due to the possibility that these finely layered, volatile-rich deposits hold a record of recent eras in Martian climate history. The PLD have been a target of imaging and other sensors in the last several decades, but only recently has it been possible to obtain a moderately high resolution image map, using the visible sensor on 2001 Mars Odyssey's Thermal Emission Imaging System (THEMIS). THEMIS has acquired a 36 meter/pixel contiguous single-band visible image data set of the south polar layered deposits (SPLD), during the southern spring in 2003. The data will undoubtedly be applied to many problems in Mars polar studies. We use these images to further characterize the population of impact craters on the SPLD, and the implications of the observed population for the age and evolution of the SPLD.

Plaut, J. J.↗
NASA NTRS2003

THEMIS Visible Imaging of the South Polar Layered Deposits, Martian Southern Spring, 2003

The polar layered deposits (PLD) of Mars have attracted considerable attention since their identification in Mariner 9 images, largely due to the possibility that these finely layered, volatile-rich deposits hold a record of recent eras in Martian climate history. The PLD have been a target of imaging and other sensors in the last several decades, but only recently has it been possible to obtain a moderately high resolution image map, using the visible sensor on 2001 Mars Odyssey s Thermal Emission Imaging System (THEMIS). We report here on the acquisition of a 36 meter/pixel contiguous single-band visible image data set of the south polar layered deposits (SPLD), obtained during early southern spring in 2003. The data will undoubtedly be applied to many problems in Mars polar studies. We will discuss here, and in more detail at the Conference, the use of these images to further characterize the population of impact craters on the SPLD, and the implications of the observed population for the age and evolution of the SPLD.

Plaut, J. J.↗
NASA NTRS2003

Themis Visible Imaging of the South Polar Layered Deposits, Martian Southern Spring, 2003

The polar layered deposits (PLD) of Mars have attracted considerable attention since their identification in Mariner 9 images, largely due to the possibility that these finely layered, volatile-rich deposits hold a record of recent eras in Martian climate history. The PLD have been a target of imaging and other sensors in the last several decades, but only recently has it been possible to obtain a moderately high resolution image map, using the visible sensor on 2001 Mars Odyssey's Thermal Emission Imaging System (THEMIS). We report here on the acquisition of a 36 meter/pixel contiguous single-band visible image data set of the south polar layered deposits (SPLD), obtained during early southern spring in 2003. The data will undoubtedly be applied to many problems in Mars polar studies.

Mariner 9↗
NASA NTRS2013

Cryogenic Optical Performance of a Light-weight Mirror Assembly for Future Space Astronomical Telescopes: Optical Test Results and Thermal Optical Model

A 40 cm diameter mirror assembly was interferometrically tested at room temperature down to 250 degrees Kelvin for thermal deformation. The 2.5 m radius of curvature spherical mirror assembly was constructed by low temperature fusing three abrasive waterjet core sections between two face sheets. The 93% lightweighted Corning ULE mirror assembly represents the current state of the art for future UV, optical, near IR space telescopes. During the multiple thermal test cycles, test results of interferometric test, thermal IR images of the front face were recorded in order to validate thermal optical model.

Eng, Ron↗
NASA NTRS2013

Cryogenic Optical Performance of a Lightweighted Mirror Assembly for Future Space Astronomical Telescopes: Correlating Optical Test Results and Thermal Optical Model

A 43cm diameter stacked core mirror demonstrator was interferometrically tested at room temperature down to 250 degrees Kelvin for thermal deformation. The 2.5m radius of curvature spherical mirror assembly was constructed by low temperature fusing three abrasive waterjet core sections between two CNC pocket milled face sheets. The 93% lightweighted Corning ULE® mirror assembly represents the current state of the art for future UV, optical, near IR space telescopes. During the multiple thermal test cycles, test results of interferometric test, thermal IR images of the front face were recorded in order to validate thermal optical model.

Eng, Ron↗
NASA NTRS2017

Plateaus and Sinuous Ridges as the Fingerprints of Lava Flow Inflation in the Eastern Tharsis Plains of Mars

The Tharsis Montes rift aprons are composed of outpourings of lava from chaotic terrains to the northeast and southwest flank of each volcano. Sinuous and branching channel networks that are present on the rift aprons suggest the possibility of fluvial processes in their development, or erosion by rapidly emplaced lavas, but the style of lava flow emplacement throughout rift apron development is not clearly understood. To better characterize the style of lava emplacement and role of fluvial processes in rift apron development, we conducted morphological mapping of the Pavonis Mons southwest rift apron and the eastern Tharsis plains using images from the High Resolution Imaging Science Experiment (HiRISE), Mars Orbiter Camera (MOC), Context Camera (CTX), Thermal Emission Imaging System (THEMIS), and High Resolution Stereo Camera (HRSC) along with the Mars Orbiter Laser Altimeter (MOLA) Precision Experiment Data Records (PEDRs) and gridded data. Our approach was to: (1) search for depositional fans at the slope break between the rift apron and adjacent low slope plains; (2) determine if there is evidence that previously formed deposits might have been buried by plains units; (3) characterize the Tharsis plains morphologies east of Pavonis Mons; and (4) assess their relationship to the rift apron units. We have not identified topographically significant depositional fans, nor did we observe evidence to suggest that plains units have buried older rift apron units. Flow features associated with the rift apron are observed to continue across the slope break onto the plains. In this area, the plains are composed of a variety of small fissures and low shield vents around which broad channel-fed and tube-fed flows have been identified. We also find broad, flat-topped plateaus and sinuous ridges mixed among the channels, tubes and vents. Flat-topped plateaus and sinuous ridges are morphologies that are analogous to those observed on the coastal plain of Hawai'i, where lava flows have advanced from the volcano's several degree flank onto the nearly zero degree coastal plain. When local volumetric flow rates are low, flow fronts tend to spread laterally and often thicken via endogenous growth, or inflation, of the sheet-like flow units. If flow advance is restricted by existing topography into narrow pathways, inflation can be focused into sinuous, elongate ridges. The presence of plateaus and ridges-emplaced from the rift zones, across the plains to the east of Pavonis Mons-and a lack of fan-like features, or evidence for their burial, are consistent with rift apron lavas crossing a slope break with low local volumetric flow rates that led to inflation of sheet-like and tube-fed lava flows.

Bleacher, Jacob E.↗
NASA NTRS1986

Groundbased infrared imaging of Comet Giacobini-Zinner - The distribution of dust during the ICE flyby

A thermal-infrared image of Comet Giacobini-Zinner has been used to determine the spatial distribution of dust grains in the Comet's coma. In the present paper the results of this imaging which bear on the expected impact rate of dust grains on the International Cometary Explorer (ICE) are emphasized. The expected impact rate is calculated for a range of grain radii. For particle sizes comparable to those inferred for most comets, the impact rate is on the order of several hundred per second. This rate is in agreement with the predictions by Divine (1985), but it is more than two orders of magnitude larger than the rate observed by ICE if the observed impacts were on the spacecraft body. However, the observed impact rate is roughly comparable to that inferred from the infrared imaging if, as suggested by Gurnett et al. (1986), the impacts were on the ICE antennae, which had a much smaller cross-sectional area than the spacecraft body.

Campins, H.↗
NASA NTRS1970

Multispectral analysis of limestone, dolomite, and granite, Mill Creek, Oklahoma

Spectral reflectance and thermal emission data were collected at the Mill Creek, Oklahoma test site during NASA missions 132 and 133 in June 1970. The data were collected by three aircraft flown several times during the diurnal cycle at altitudes of 150 to 17,000 m above mean terrain. Reflectance of the main rock types (limestone, dolomite, and granite) was determined from the data collected using a 12-channel multispectral scanner during mission 133 and from thermal infrared images recorded during mission 132 on an RS-7 scanner from 17,000 m above terrain. A preliminary rock recognition map was generated automatically using data collected from 900 m above terrain. The discrimination provided by the map is reasonably accurate. Misidentification occurred in areas of unusually high dolomite reflectivity. High altitude thermal infrared (10 to 12 micrometers) images show regional folds and faults distinguished by the presence of thermally contrasting materials. Linear and curvilinear structural features two to three times smaller than the nominal 17 m resolution could be detected.

Rowan, L. C.↗
DOE OSTI2023

High-throughput terahertz imaging: progress and challenges

Abstract Many exciting terahertz imaging applications, such as non-destructive evaluation, biomedical diagnosis, and security screening, have been historically limited in practical usage due to the raster-scanning requirement of imaging systems, which impose very low imaging speeds. However, recent advancements in terahertz imaging systems have greatly increased the imaging throughput and brought the promising potential of terahertz radiation from research laboratories closer to real-world applications. Here, we review the development of terahertz imaging technologies from both hardware and computational imaging perspectives. We introduce and compare different types of hardware enabling frequency-domain and time-domain imaging using various thermal, photon, and field image sensor arrays. We discuss how different imaging hardware and computational imaging algorithms provide opportunities for capturing time-of-flight, spectroscopic, phase, and intensity image data at high throughputs. Furthermore, the new prospects and challenges for the development of future high-throughput terahertz imaging systems are briefly introduced.

36 MATERIALS SCIENCE↗
NASA NTRS2002

Light-Toned, Layered Outcrops of Northern Terra Meridiani Mars: Viking, Phobos 2, and Mars Global Surveyor Observations

Locating outcrops of sedimentary rock on Mars is an important step toward deciphering the planet's geologic and climatologic record. Sedimentary rock representing the earliest martian environments, are of particular interest in this context. This is a report about a vast exposure of material proposed to be martian sedimentary rock. The outcrops cover an area (approximately sq 300,000 km) roughly the size of the Colorado Plateau in North America (approximately 260,000 sq km). The materials occur in northern Terra Meridiani, near of one of the four sites being considered for a 2004 NASA Mars Exploration Rover (MER) landing. The landing ellipse, centered at deg S, deg W, lies in a region exhibiting smooth and rough (at meter scale) dark-toned surfaces, with scattered light-toned patches. Stratigraphically, the dark-toned materials at the MER site lie unconformably on top of a previously-eroded, light-toned surface; the light-toned patches in the landing ellipse are geologic windows down to this lower stratigraphic unit. North of the landing ellipse, the light-toned materials are well-exposed because the darker materials have been removed, stranding outlier remnants in a few locations. The light-toned materials are layered, vertically heterogeneous, and exhibit lateral continuity over hundreds of kilometers. Eroded layers produce cliffs; some outcrops are expressed as mesas, buttes, and spires; and impact craters ranging in diameter from a few meters to tens of kilometers are interbedded with the layers. The purpose of this report is to summarize the results of greater than 6 years of photogeologic investigation into the nature of the light-toned outcrops of northern Terra Meridiani. The work is a 'snapshot' of progress made toward eventual geologic mapping and establishment of the stratigraphic sequence for the materials through 30 September 2002, a day prior to the first release of Mars Odyssey Thermal Emission Imaging System (THEMIS) data to the NASA Planetary Data System (PDS). The main body of data examined were Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images acquired through 30 September 2002. The data also 2 include Viking orbiter images, a Phobos 2 Termoscan image, MGS Mars Orbiter Laser Altimeter (MOLA) topographic observations, and the products of published Viking Infrared Thermal Mapper (IRTM) and Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) analyses. Through September 2002, over 126,000 MOC images had been acquired, and greater than 600 of the MOC narrow angle (1.5-12 m/pixel) images occur within the portions of Terra Meridiani and southwestern Arabia Terra.

Edgett, Kenneth S.↗