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At least 181 records · Page 10

The TESS-Keck Survey. I. A Warm Sub-Saturn-mass Planet and a Caution about Stray Light in TESS Cameras

We report the detection of a Saturn-size exoplanet orbiting HD 332231 (TOI 1456) in light curves from the Transiting Exoplanet Survey Satellite (TESS). HD 332231—an F8 dwarf star with a V-band magnitude of 8.56—was observed by TESS in Sectors 14 and 15. We detect a single-transit event in the Sector 15 presearch data conditioning (PDC) light curve. We obtain spectroscopic follow-up observations of HD 332231 with the Automated Planet Finder, Keck I, and SONG telescopes. The orbital period we infer from radial velocity (RV) observations leads to the discovery of another transit in Sector 14 that was masked by PDC due to scattered light contamination. A joint analysis of the transit and RV data confirms the planetary nature of HD 332231 b, a Saturn-size (0.867 (+0.027,-0.025 R(J)), sub-Saturn-mass (0.244 ± 0.021M(J)) exoplanet on a 18.71 day circular orbit. The low surface gravity of HD 332231 b and the relatively low stellar flux it receives make it a compelling target for transmission spectroscopy. Also, the stellar obliquity is likely measurable via the Rossiter–McLaughlin effect, an exciting prospect given the 0.14 au orbital separation of HD 332231 b. The spectroscopic observations do not provide substantial evidence for any additional planets in the HD 332231 system, but continued RV monitoring is needed to further characterize this system. We also predict that the frequency and duration of masked data in the PDC light curves for TESS Sectors 14–16 could hide transits of some exoplanets with orbital periods between 10.5 and 17.5 days.

Paul A. Dalba↗

Effect of Microscopic Damage Events on Static and Ballistic Impact Strength of Triaxial Braid Composites

In previous work, the ballistic impact resistance of triaxial braided carbon/epoxy composites made with large flat tows (12k and 24k) was examined by impacting 2 X2 X0.125" composite panels with gelatin projectiles. Several high strength, intermediate modulus carbon fibers were used in combination with both untoughened and toughened matrix materials. A wide range of penetration thresholds were measured for the various fiber/matrix combinations. However, there was no clear relationship between the penetration threshold and the properties of the constituents. During some of these experiments high speed cameras were used to view the failure process, and full-field strain measurements were made to determine the strain at the onset of failure. However, these experiments provided only limited insight into the microscopic failure processes responsible for the wide range of impact resistance observed. In order to investigate potential microscopic failure processes in more detail, quasi-static tests were performed in tension, compression, and shear. Full-field strain measurement techniques were used to identify local regions of high strain resulting from microscopic failures. Microscopic failure events near the specimen surface, such as splitting of fiber bundles in surface plies, were easily identified. Subsurface damage, such as fiber fracture or fiber bundle splitting, could be identified by its effect on in-plane surface strains. Subsurface delamination could be detected as an out-of-plane deflection at the surface. Using this data, failure criteria could be established at the fiber tow level for use in analysis. An analytical formulation was developed to allow the microscopic failure criteria to be used in place of macroscopic properties as input to simulations performed using the commercial explicit finite element code, LS-DYNA. The test methods developed to investigate microscopic failure will be presented along with methods for determining local failure criteria that can be used in analysis. Results of simulations performed using LS-DYNA will be presented to illustrate the capabilities and limitations for simulating failure during quasi-static deformation and during ballistic impact of large unit cell size triaxial braid composites.

Littell, Justin D.↗

International Space Station Data Collection for Disaster Response

Natural disasters - including such events as tropical storms, earthquakes, floods, volcanic eruptions, and wildfires -effect hundreds of millions of people worldwide, and also cause billions of dollars (USD) in damage to the global economy. Remotely sensed data acquired by orbital sensor systems has emerged as a vital tool to identify the extent of damage resulting from a natural disaster, as well as providing near-real time mapping support to response efforts on the ground and humanitarian aid efforts. The International Space Station (ISS) is a unique terrestrial remote sensing platform for acquiring disaster response imagery. Unlike automated remote-sensing platforms it has a human crew; is equipped with both internal and externally-mounted remote sensing instruments; and has an inclined, low-Earth orbit that provides variable views and lighting (day and night) over 95 percent of the inhabited surface of the Earth. As such, it provides a useful complement to free-flyer based, sun-synchronous sensor systems in higher altitude polar orbits. While several nations have well-developed terrestrial remote sensing programs and assets for data collection, many developing nations do not have ready access to such resources. The International Charter, Space and Major Disasters (also known as the "International Disaster Charter", or IDC; http://www.disasterscharter.org/home) addresses this disparity. It is an agreement between agencies of several countries to provide - on a best-effort basis - remotely sensed data of natural disasters to requesting countries in support of disaster response. The lead US agency for interaction with the IDC is the United States Geological Survey (USGS); when an IDC request or "activation" is received, the USGS notifies the science teams for NASA instruments with targeting information for data collection. In the case of the ISS, the Earth Sciences and Remote Sensing (ESRS) Unit, part of the Astromaterials Research and Exploration Science Directorate and supporting the ISS Program Science Office at NASA's Johnson Space Center, receives notification from the USGS and coordinates targeting and data collection with the NASA ISS sensor teams. If data is collected, it is passed back to the USGS for posting on their Hazards Data Distribution System and made available for download. The ISS International Partners (CSA, ESA, JAXA, Roscosmos/Energia) have their own procedures for independently supporting IDC activations using their assets on ISS, and there is currently no joint coordination with NASA ISS sensor teams. Following completion of ISS assembly, NASA remote sensing assets began collecting IDC response data in May 2012. The initial NASA ISS sensor systems available to respond to IDC activations included the ISS Agricultural Camera (ISSAC), an internal multispectral visible-near infrared wavelength system mounted in the Window Observational Research Facility, or WORF; the Crew Earth Observations (CEO) Facility, where the crew collects imagery through Station windows using off-the-shelf handheld digital visible-wavelength cameras; and the Hyperspectral Imager for the Coastal Oceans (HICO), a visible to near-infrared system mounted externally on the Japan Experiment Module Exposed Facility. The ISSAC completed its primary mission and was removed from the WORF in January 2013. It was replaced by the very high resolution ISS SERVIR Environmental Research and Visualization System (ISERV) Pathfinder, a visible-wavelength digital camera, telescope, and pointing system. Since the start of IDC response by NASA sensors on the ISS in May 2012 and as of this report, there have been eighty IDC activations; NASA sensor systems have collected data for twenty-three of these events. Of the twenty-three successful data collections, five involved 2 or more ISS sensor systems responding to the same event. Data has also been collected by International Partners in response to natural disasters, most notably JAXA and Roscosmos/Energia through the Urugan program. Data collected in response to IDC activations is delivered by the ISS sensor teams to the ESRS for quality review and transfer to the USGS, where it is ingested into the Hazards Data Distribution System, or HDDS (https://hdds.usgs.gov/hdds2/; figure 1). This system allows the local agencies that issued the IDC activation request to review and download data. The data is then used to develop secondary products useful for humanitarian response such as flood maps. As of this report, approximately 1000 images collected by NASA ISS sensor systems have been downloaded from the HDDS, indicating that the ISS has assumed a valuable role in disaster response efforts. The ISS is also a unique platform in that it will have multiple users over its lifetime, and that no single remote sensing system has a permanent internal or external berth. This scheduled turnover provides for development of new remote sensing capabilities relevant to disaster response -as well as both research and applied science-and represents a significant contribution to continuance and enhancement of the NASA mission to investigate changes on our home planet.

Stefanov, William L.↗

OGLE-2015-BLG-1649Lb: A Gas Giant Planet around a Low-mass Dwarf

We report the discovery of an exoplanet from the analysis of the gravitational microlensing event OGLE-2015-BLG-1649 that challenges the core accretion model of planet formation and appears to support the disk instability model. The planet/host-star mass ratio is q = 7.2 × 10^(−3) and the projected separation normalized to the angular Einstein radius is s = 0.9. We conducted high-resolution follow-up observations using the Infrared Camera and Spectrograph (IRCS) camera on the Subaru telescope and are able to place an upper limit on the lens flux. From these measurements we are able to exclude all host stars greater than or equal in mass to a G-type dwarf. We conducted a Bayesian analysis with these new flux constraints included as priors resulting in estimates of the masses of the host star and planet. These are ML = 0.34 ± 0.19 M⊙ and M(p)=2.5 (+1.5,-1.4) M(Jup), respectively. The distance to the system is D(L)=4.23 (+1.51, -1.64) kpc. The projected star–planet separation is a(┴)=2.07 (+0.65,-0.77) au. The estimated relative lens-source proper motion, ~7.1 mas/yr, is fairly high and thus the lens can be better constrained if additional follow-up observations are conducted several years after the event.

M. Nagakane↗

Detecting Layer Height of Smoke and Dust Aerosols Over Vegetated Land and Water Surfaces Via Oxygen Absorption Bands

We present an algorithm for retrieving aerosol layer height (ALH) and aerosol optical depth (AOD) for smoke and dust over vegetated land and water surfaces from measurements of the Earth Polychromatic Imaging Camera (EPIC) onboard the Deep Space Climate Observatory (DSCOVR). Our algorithm uses EPIC atmospheric window bands to determine AOD and then takes advantage of oxygen A and B bands to derive ALH. We applied this algorithm on several dust and smoke events. Validation shows our results are of high accuracy.

Jing Zeng↗

Dust Lifting Observations with the Mars Science Laboratory Navigation Cameras

Martian dust lifting is believed to occur through two primary mechanisms: dust devils and wind stress forced dust lifting. Gale Crater's varied terrain and meteorology provide a unique in situ perspective on Martian dust lifting, with the Mars Science Laboratory Curiosity rover passing through both conditions and locations detrimental to dust lifting (e.g., the crater floor) and those with active sand motion and frequent dust lifting (e.g., the Bagnold Dunes). Between L s = 248° in Mars Year 33 and L s = 51° in Mars Year 37, over ∼3.5 Mars years and 2,300 sols, the rover's Navigation Cameras took 1,260 dedicated image sequences to search for dust lifting. Approximately 42.7% of all sequences, and 9.5% of the total images have shown active dust lifting, both dust devils and linear/straight-line wind stress dust lifting. 79% of dust lifting events are classified as dust devils, while ∼16% are linear wind stress dust lifting and the remainder are of an indeterminate type. We analyze this large catalog of dust lifting events to provide ground truth on theoretical and model expectations of dust lifting and show that dust lifting in Gale Crater occurs throughout the Martian year, is strongly peaked in frequency near solar noon (even after accounting for observational biases), and that dust lifting shows an affinity for sand-covered surfaces which highlights the importance of saltating sand grains for Martian dust lifting in both dust devils and wind stress forced lifting.

Scott D. Guzewich↗

Validation Ice Crystal Icing Engine Test in the Propulsion Systems Laboratory at NASA Glenn Research Center

The Propulsion Systems Laboratory (PSL) is an existing altitude simulation jet engine test facility located at NASA Glenn Research Center in Clevleand, OH. It was modified in 2012 with the integration of an ice crystal cloud generation system. This paper documents the inaugural ice crystal cloud test in PSLthe first ever full scale, high altitude ice crystal cloud turbofan engine test to be conducted in a ground based facility. The test article was a Lycoming ALF502-R5 high bypass turbofan engine, serial number LF01. The objectives of the test were to validate the PSL ice crystal cloud calibration and engine testing methodologies by demonstrating the capability to calibrate and duplicate known flight test events that occurred on the same LF01 engine and to generate engine data to support fundamental and computational research to investigate and better understand the physics of ice crystal icing in a turbofan engine environment while duplicating known revenue service events and conducting test points while varying facility and engine parameters. During PSL calibration testing it was discovered than heated probes installed through tunnel sidewalls experienced ice buildup aft of their location due to ice crystals impinging upon them, melting and running back. Filtered city water was used in the cloud generation nozzle system to provide ice crystal nucleation sites. This resulted in mineralization forming on flow path hardware that led to a chronic degradation of performance during the month long test. Lacking internal flow path cameras, the response of thermocouples along the flow path was interpreted as ice building up. Using this interpretation, a strong correlation between total water content (TWC) and a weaker correlation between median volumetric diameter (MVD) of the ice crystal cloud and the rate of ice buildup along the instrumented flow path was identified. For this test article the engine anti-ice system was required to be turned on before ice crystal icing would occur. The ice crystal icing event, an uncommanded reduction in thrust, was able to be turned on and off by manipulating cloud TWC. A flight test point where no ice crystal icing event occurred was also duplicated in PSL. Physics based computational tools were successfully used to predict tunnel settings to induce ice buildup along the low pressure compression system flow path for several test points at incrementally lower altitudes, demonstrating that development of ice crystal icing scaling laws is potentially feasible. Analysis of PSL test data showed that uncommanded reduction in thrust occurs during ice crystal cloud on operation prior to fan speed reduction. This supports previous findings that the reduction of thrust for this test article is due to ice buildup leading to a restricted airflow from either physical or aerodynamic blockage in the engine core flow path.

Ice Crystal Icing↗

Validation Ice Crystal Icing Engine Test in the Propulsion Systems Laboratory at NASA Glenn Research Center

The Propulsion Systems Laboratory (PSL) is an existing altitude simulation jet engine test facility located at NASA Glenn Research Center in Cleveland, OH. It was modified in 2012 with the integration of an ice crystal cloud generation system. This paper documents the inaugural ice crystal cloud test in PSL--the first ever full scale, high altitude ice crystal cloud turbofan engine test to be conducted in a ground based facility. The test article was a Lycoming ALF502-R5 high bypass turbofan engine, serial number LF01. The objectives of the test were to validate the PSL ice crystal cloud calibration and engine testing methodologies by demonstrating the capability to calibrate and duplicate known flight test events that occurred on the same LF01 engine and to generate engine data to support fundamental and computational research to investigate and better understand the physics of ice crystal icing in a turbofan engine environment while duplicating known revenue service events and conducting test points while varying facility and engine parameters. During PSL calibration testing it was discovered than heated probes installed through tunnel sidewalls experienced ice buildup aft of their location due to ice crystals impinging upon them, melting and running back. Filtered city water was used in the cloud generation nozzle system to provide ice crystal nucleation sites. This resulted in mineralization forming on flow path hardware that led to a chronic degradation of performance during the month long test. Lacking internal flow path cameras, the response of thermocouples along the flow path was interpreted as ice building up. Using this interpretation, a strong correlation between total water content (TWC) and a weaker correlation between median volumetric diameter (MVD) of the ice crystal cloud and the rate of ice buildup along the instrumented flow path was identified. For this test article the engine anti-ice system was required to be turned on before ice crystal icing would occur. The ice crystal icing event, an uncommanded reduction in thrust, was able to be turned on and off by manipulating cloud TWC. A flight test point where no ice crystal icing event occurred was also duplicated in PSL. Physics based computational tools were successfully used to predict tunnel settings to induce ice buildup along the low pressure compression system flow path for several test points at incrementally lower altitudes, demonstrating that development of ice crystal icing scaling laws is potentially feasible. Analysis of PSL test data showed that uncommanded reduction in thrust occurs during ice crystal cloud on operation prior to fan speed reduction. This supports previous findings that the reduction of thrust for this test article is due to ice buildup leading to a restricted airflow from either physical or aerodynamic blockage in the engine core flow path.

Turbofan Engine↗

International Space Station (ISS) External Television (TV) Camera Shutdown Investigation

In the early morning of January 15, 2006, the Stardust Sample Return Capsule (SRC) successfully delivered its precious cargo of cometary particles to the awaiting recovery team at the Utah Test and Training Range (UTTR). As the SRC entered at 12.8 km/s, the fastest manmade object to traverse the atmosphere, a team of researchers imaged the event aboard the NASA DC-8 airborne observatory. At SRC entry, the airplane was at an altitude of 11.9 km positioned within 6.4 km of the prescribed, preferred target view location. The incoming SRC was first acquired approximately 18 seconds (s) after atmospheric interface and tracked for approximately 60 s, an observation period that is roughly centered in time around predicted peak heating.

Kichak, Robert↗

June 2023 Canadian Wildfire Effects on Hampton Roads VA using ASDC Data

In June of 2023 thousands of acres of wildfires spread across northwestern Canada. This event emitted huge amounts of smoke, and pollutants that travelled east across the North America, the Atlantic ocean and eventually all the way to Continental Europe. This smoke created a dangerous air quality event throughout the Atlantic Coast. As climate change increases the prevalence of wildfires more cities and states will be affected by the dangerous smoke and pollutants produced by these events. In this poster we documented and investigated the June 06th Air Quality Event over Hampton Roads, VA. To perform a comparative analysis, we utilized two data sources: NASA’s Atmospheric Science Data Center we used the Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), the Deep Space Climate ObserVatoRy (DSCOVR) Enhanced Polychromatic Imaging Camera (EPIC), data product, and the EPA’s ground-based Air Quality System (AQS).

Air Quality↗

High speed multiwire photon camera

An improved multiwire proportional counter camera having particular utility in the field of clinical nuclear medicine imaging. The detector utilizes direct coupled, low impedance, high speed delay lines, the segments of which are capacitor-inductor networks. A pile-up rejection test is provided to reject confused events otherwise caused by multiple ionization events occuring during the readout window.

Lacy, Jeffrey L.↗

High speed multiwire photon camera

An improved multiwire proportional counter camera having particular utility in the field of clinical nuclear medicine imaging. The detector utilizes direct coupled, low impedance, high speed delay lines, the segments of which are capacitor-inductor networks. A pile-up rejection test is provided to reject confused events otherwise caused by multiple ionization events occurring during the readout window.

Lacy, Jeffrey L.↗

3D GeoWall Analysis System for Shuttle External Tank Foreign Object Debris Events

An analytical, advanced imaging method has been developed for the initial monitoring and identification of foam debris and similar anomalies that occur post-launch in reference to the space shuttle s external tank (ET). Remote sensing technologies have been used to perform image enhancement and analysis on high-resolution, true-color images collected with the DCS 760 Kodak digital camera located in the right umbilical well of the space shuttle. Improvements to the camera, using filters, have added sharpness/definition to the image sets; however, image review/analysis of the ET has been limited by the fact that the images acquired by umbilical cameras during launch are two-dimensional, and are usually nonreferenceable between frames due to rotation translation of the ET as it falls away from the space shuttle. Use of stereo pairs of these images can enable strong visual indicators that can immediately portray depth perception of damaged areas or movement of fragments between frames is not perceivable in two-dimensional images. A stereoscopic image visualization system has been developed to allow 3D depth perception of stereo-aligned image pairs taken from in-flight umbilical and handheld digital shuttle cameras. This new system has been developed to augment and optimize existing 2D monitoring capabilities. Using this system, candidate sequential image pairs are identified for transformation into stereo viewing pairs. Image orientation is corrected using control points (similar points) between frames to place the two images in proper X-Y viewing perspective. The images are then imported into the WallView stereo viewing software package. The collected control points are used to generate a transformation equation that is used to re-project one image and effectively co-register it to the other image. The co-registered, oriented image pairs are imported into a WallView image set and are used as a 3D stereo analysis slide show. Multiple sequential image pairs can be used to allow forensic review of temporal phenomena between pairs. The observer, while wearing linear polarized glasses, is able to review image pairs in passive 3D stereo.

Brown, Richard↗

Coordinated observations of the magnetosphere - The development of a substorm.

Coordinated observations of a substorm are reported by using data from all-sky camera (ASCA) stations near the northern conjugate of the ATS 5 geostationary satellite, plasma and magnetic-field experiments on the ATS 5 satellite, Vela 5B at 18 earth radii in the magnetotail, the Heos 1 interplanetary probe, and ground-based magnetograms. The substorm event occurred after a very quiet day and was preceded by a development period during which the interplanetary field turned southward and the plasma energy density increased near the earth on the nightside. This period was also evidenced by a depression of the midlatitude H component of the geomagnetic field at the earth's surface. The auroral breakup was preceded by the appearance of quiet arcs, the leveling off of the plasma energy density increase at ATS, and the disappearance of the tail plasma at 18 earth radii.

Mende, S. B.↗

The Photogrammetric Appendage Structural Dynamics Experiment

The Photogrammetric Appendage Structural Dynamics Experiment (PASDE) is a Hitchhiker payload scheduled to fly as part of the International Space Station (ISS) Phase-1 flight program to the Russian Space Station Mir. The objective of the first flight of PASDE on STS-74 is to obtain video images of the Mir Kvant-2 solar array response to various structural dynamic excitation events. This experiment will demonstrate the use of photogrammetric techniques for on-orbit structural dynamics measurements. Photogrammetric measurements will provide a low cost alternative to appendage mounted accelerometers to the ISS program. The PASDE experiment hardware consists of three instruments each containing two video cameras, two video tape recorders, a modified video signal time inserter, and associated avionics boxes. The instruments were designed and built at the NASA Langley Research Center, and are integrated into standard Hitchhiker canisters at the NASA Goddard Space Flight Center. The Hitchhiker canisters are then installed into the Space Shuttle cargo bay in locations selected to achieve good video coverage and photogrammetric geometry. The measurement resolution of the instruments is expected to be on the order of 0.25 cm (0.1 in.).

Gilbert, Michael G.↗

A Bright Lunar Impact Flash Linked to the Virginid Meteor Complex

Since early 2006, NASA's Marshall Space Flight Center (MSFC) has observed over 330 impact flashes on the Moon, produced by meteoroids striking the lunar surface. On 17 March 2013 at 03:50:54.312 UTC, the brightest flash of a 9-year routine observing campaign was observed by two 0.35 m telescopes at MSFC. The camera onboard the Lunar Reconnaissance Orbiter (LRO), a NASA spacecraft mapping the Moon from lunar orbit, discovered the fresh crater associated with this impact [1] approximately 3 km from the location predicted by a newly developed geolocation technique [2]. The meteoroid impactor responsible for this event may have been part of a stream of large particles encountered by the Earth/Moon associated with the Virginid Meteor Complex, as evidenced by a cluster of five fireballs seen in Earth's atmosphere on the same night by the NASA All Sky Fireball Network [3] and the Southern Ontario Meteor Network [4]. Crater size calculations based on assumptions derived from fireball measurements yielded an estimated crater diameter of 10-23 m rim-to-rim using the Holsapple [5] and Gault [6] models, a result consistent with the observed crater measured to be 18 m across. This is the first time a lunar impact flash has been associated with fireballs in Earth's atmosphere and an observed crater.

Moser, D. E.↗

Imaging studies of comets

Schmidt camera plates of comet Bradfield were secured on several nights in October 1987. The images of October 20 show the development of a huge bend in the plasma tail travelling several hundred kilometers per second down the tail; the likely solar-wind origin of this event is being explored. A charged coupled device (CCD) detector has been obtained. Calibration of the CCD is still underway, but high-quality, filtered cometary images shoud be possible in the near future.

Niedner, Malcolm B., Jr.↗

Interaction of Burning Metal Particles

Multiple particle/droplet flames are ubiquitous in practical combustion systems, and thus the flame interaction processes are of great practical importance. This explains the strong current interest in interactive combustion phenomena. This research is aimed at the investigation of combustion parameters of microgravity model aerosols: relatively large uniform metal particles aerosolized in microgravity environment. An experiment consisting of creation and ignition of a metal multiparticle system in microgravity and high-speed video-recording of the combustion events will produce visual records of the development of individual particle flames, their interactions and the particle motion they induce simultaneously with the observation of the entire aerosol combustion process. Frame by frame analysis of the video-images taken using a high-speed movie camera will allow one to determine particle brightness temperatures and the decrease in particle diameter during combustion. Analysis of the experimental results and comparison with the results of single metal particle combustion experiments, conducted under similar microgravity conditions in the framework of a parallel program, will establish the relationship between single and multiple particle burning rates and combustion temperatures, concentrations at which the flame substructure forms rather than individual particle flames, efficiency of radiative heat transfer in metal aerosol combustion, what is the role of electrostatic forces in structuring the flame and the effect of that structure on the flame propagation rate. Although some details of fine particle aerosol clouds, such as the kinetics limited burning rate, radiative heat transfer in a system with a high specific surface, particle induced turbulence, etc., will probably not be very well simulated in the planned experiments, they are relatively well understood and can be accounted for using an adequate individual particle combustion model. On the other hand, the unknown particle interaction phenomena to be studied in this research program are generic and can be readily projected onto a cloud combustion model which would also incorporate a correction for particle size.

Dreizin, Edward L.↗