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At least 127 records · Page 7

STS-113 Mission Highlights Resource Tape Flight Days 1-3. Tape: 1 of 4

This video, part 1 of 4, shows the activities of the crew of Space Shuttle Endeavour during flight days 1-3 of STS-113. The crew consists of Commander Jim Wetherbee, Pilot Paul Lockhart, Mission Specialists Michael Lopez-Alegria and John Herrington. With them were the Expedition 6 crewmembers of the International Space Station (ISS), Ken Bowersox, Nikolai Budarin, and Don Pettit. Pre-launch procedures are shown, and the rain-delayed night launch is shown from several camera angles. On flight day 2 there was a check out of the Canadarm on Endeavour, and some intravehicular activity. Flight day 3 highlights the docking of Endeavour and the ISS, and preparation for an extravehicular activity (EVA) the following day. Earth views include the English Channel at night with a close-up of London, the coast of Ecuador, and some views of Endeavour with the Earth in the background.

Source record↗

MISR CMVs and Multiangular Views of Tropical Cyclone Inner-Core Dynamics

Multi-camera stereo imaging of cloud features from the MISR (Multiangle Imaging SpectroRadiometer) instrument on NASA's Terra satellite provides accurate and precise measurements of cloud top heights (CTH) and cloud motion vector (CMV) winds. MISR observes each cloudy scene from nine viewing angles (Nadir, +/-26(sup o), +/-46(sup o), +/-60(sup o), +/-70(sup o)) with approximatel 275-m pixel resolution. This paper provides an update on MISR CMV and CTH algorithm improvements, and explores a high-resolution retrieval of tangential winds inside the eyewall of tropical cyclones (TC). The MISR CMV and CTH retrievals from the updated algorithm are significantly improved in terms of spatial coverage and systematic errors. A new product, the 1.1-km cross-track wind, provides high accuracy and precision in measuring convective outflows. Preliminary results obtained from the 1.1-km tangential wind retrieval inside the TC eyewall show that the inner-core rotation is often faster near the eyewall, and this faster rotation appears to be related linearly to cyclone intensity.

hurricanes↗

Theodolite with CCD Camera for Safe Measurement of Laser-Beam Pointing

The simple addition of a charge-coupled-device (CCD) camera to a theodolite makes it safe to measure the pointing direction of a laser beam. The present state of the art requires this to be a custom addition because theodolites are manufactured without CCD cameras as standard or even optional equipment. A theodolite is an alignment telescope equipped with mechanisms to measure the azimuth and elevation angles to the sub-arcsecond level. When measuring the angular pointing direction of a Class ll laser with a theodolite, one could place a calculated amount of neutral density (ND) filters in front of the theodolite s telescope. One could then safely view and measure the laser s boresight looking through the theodolite s telescope without great risk to one s eyes. This method for a Class ll visible wavelength laser is not acceptable to even consider tempting for a Class IV laser and not applicable for an infrared (IR) laser. If one chooses insufficient attenuation or forgets to use the filters, then looking at the laser beam through the theodolite could cause instant blindness. The CCD camera is already commercially available. It is a small, inexpensive, blackand- white CCD circuit-board-level camera. An interface adaptor was designed and fabricated to mount the camera onto the eyepiece of the specific theodolite s viewing telescope. Other equipment needed for operation of the camera are power supplies, cables, and a black-and-white television monitor. The picture displayed on the monitor is equivalent to what one would see when looking directly through the theodolite. Again, the additional advantage afforded by a cheap black-and-white CCD camera is that it is sensitive to infrared as well as to visible light. Hence, one can use the camera coupled to a theodolite to measure the pointing of an infrared as well as a visible laser.

Crooke, Julie A.↗

Recent Development Work with Self-Aligned Focusing Schlieren

A novel compact focusing schlieren instrument has recently been developed that eliminates the need for a separate source and cutoff grid. The technique works by projecting an image of a grid onto a retroreflective surface and then reimaging the projection back onto the original grid. By manipulating the polarization state of the light passing through the instrument, a single Rochon polarizing prism can be used to adjust the schlieren sensitivity by translating it along the instrument’s optical axis, which changes the in-plane offset between the reimaged projection and the original grid. This arrangement makes the instrument inherently self-aligned. Relative to conventional focusing schlieren instruments, which require alignment of a separate source grid and cutoff grid to achieve sensitivity, the setup time required in order to obtain high quality focusing schlieren images is significantly reduced. Further, the self-aligned nature of this instrument makes it insensitive to vibrations and allows for on-the-fly adjustments to field-of-view. In this paper we discuss recent work that has been performed to expand the capabilities of this self-aligned focusing schlieren instrument including: schlieren visualization at extreme angles for optically-restricted test facilities, 3D schlieren visualization using a light field camera, acquisition of high quality focusing schlieren images from facilities with low quality windows, and obtaining focusing schlieren images in full-scale ground test facilities.

Brett Bathel↗

Mars Mapping Technology Brings Main Street to Life

The Red Planet has long held a particular hold on the human psyche. From the Roman god of war to Orson Welles infamous Halloween broadcast, our nearest planetary neighbor has been viewed with curiosity, suspicion, and awe. Pictures of Mars from 1965 to the present reveal familiar landscapes while also challenging our perceptions and revising our understanding of the processes at work in planets. Frequent discoveries have forced significant revisions to previous theories. Although Mars shares many familiar features with Earth, such as mountains, plains, valleys, and polar ice, the conditions on Mars can vary wildly from those with which we are familiar. The apparently cold, rocky, and dusty wasteland seen through the eyes of spacecraft and Martian probes hints at a dynamic past of volcanic activity, cataclysmic meteors, and raging waters. New discoveries continue to revise our view of our next-door neighbor, and further exploration is now paving the way for a human sortie to the fourth stone from the Sun. NASA s Mars Exploration Program, a long-term effort of robotic exploration, utilizes wide-angle stereo cameras mounted on NASA s twin robot geologists, the Mars Exploration Rovers (MERs), launched in 2003. The rovers, named "Spirit" and "Opportunity," celebrated 4 Earth years of exploration on January 3, 2008, and have sent back a wealth of information on the terrain and composition of the Martian surface. Their marathon performance has far outlasted the intended 90 days of operation, and the two intrepid explorers promise more images and data.

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(abstract) Radiometric Calibration of the Multi-angle Imaging Spectro-Radiometer

The EOS/MISR instrument has completed preflight calibration and characterization of its nine cameras. The radiometric calibration requirements includes absolute radiometric accuracy to 3 percent. To meet this challenging requirement MISR has employed detector based calibration methodology. The source, a 1.65 m integrating sphere, is spatially and spectrally featureless. Thus, when viewing scenes that are likewise homogeneous, the sensor incident radiance is easily retrieved to high accuracy. To enhance the radiance product for arbitrary scene types, however, MISR is planning to incorporate spectral out-of-band, point-spread function deconvolution, and pixel nonuniformity of response corrections. A summary of the preflight calibration is presented in this paper, as well as the error uncertainties for specific scene types with and without these processing corrections.

radiometric calibration EOS MISR↗

Application of Digital Image Correlation in Wind Tunnel

Digital image correlation (DIC) is a non-contact measurement technique that has been used in various applications in multiple industries, from microscopic specimens all the way to large scale structures. This project involved using DIC to capture wing deflection under simulated wind loading at various angles of attack (AoA). A subscale model of a fixed-wing aircraft, shown in Figure 1, was used in the 14-footby 22-footsubsonicwind tunnel at the NASA Langley Research Center. The setup used two pairs of cameras mounted on the ceiling of the tunnel to view the starboard and port side wings. Aluminum framing was used to rigidly mount the cameras to beams in the ceiling. Camera setup challenges due to the confined space included obtaining even lighting and working around infrared (IR) cameras that were used to capture the flow over the wing. Remote connection was used to access data acquisition computers from computers in the control room. Eight measurement locations on each wing were made of 1-inch-diametercircular silver dry transfer decals that did not alter the air flow across the wing. These circles were speckled with a black ink pen and were used for the IR camera as well as for DIC systems. A mock setup outside the wind tunnel was used to optimize the camera setup and verify that the speckled tape provided sufficient correlation. DIC was used to track the position of seven locations as the AoA of the subscale model changed from −10 degrees to +10 degrees in 1-degree increments. The model was rotated at a fixed height about the center of the fuselage from −7 degrees to +10 degrees. The height of the model had to be lowered to achieve AoA slower than −7degrees due to geometric constraints of the cart supporting the model and the wind tunnel. The source of light was stationary relative to the model, so the exposure time had to be adjusted for different wing regions and AoA values. The three-dimensional (3D) visualization of the markings and the two-dimensional (2D) projection of these points onto the port wing at 0-degree AoA is shown in Figure 2.

Matlock Mennu↗

The Development of a Real-Time Optical Angle-of-Attack Measurement Capability at the NASA Ames Unitary Plan Wind Tunnel

The following details the implementation of a real-time optical angle-of-attack capability under development at the NASA Ames Unitary Plan Wind Tunnel (UPWT). Recent advancements in the integration of high bandwidth imaging systems at the Ames UPWT has laid the groundwork for the deployment of a calibrated, imaging based measurement capability. Some of the measurement goals of this data system include: an estimation of the orientation of a wind tunnel model to six degrees of freedom, measurements made at framerates high enough to time resolve model dynamics, triangulate corresponding points of interest from multiple camera views in three-dimensional space, acquire imagery with no impact to the productivity of the test matrix, provide results in real-time, and finally compute an estimation of the errors associated with the measurement. The following will outline the imaging hardware and data systems architecture, describe the data flow and image processing routines currently implemented, and explore example data and results from previous wind tunnel test entries.

Ground Testing↗

Multi-Angle Imager for Aerosols (MAIA) spectral and radiometric calibration

The Multi-angle Imaging SpectroRadiometer (MISR) was launched as part of NASA’s Terra satellite suite of instruments. Still operational, it makes use of observations from multiple view angles to retrieve aerosol abundance and particle properties. The Multi-Angle Imager for Aerosols (MAIA) instrument improves on this heritage by incorporating polarimetry and an expanded spectral range. Combining these data with surface measurements, the relationship between pollution and human health will be explored. MAIA has just completed camera testing, building on the experience from MISR. Spectral calibration now makes use of a double subtractive monochromator, built with the intent to allow the exit slit output to be uniform in spectral content. For radiometric testing, hardware upgrades have included adding UV lamps to the 1.65 cm (65") integrating sphere, use of a NIST-traceable sphere to establish absolute radiances, and the addition of a UV transfer spectrometer to support characterization of the sphere output from 300 to 2500 nm. During camera build, Newton’s rings were observed in the detector Quantum Efficiency (QE) measurements. This is due to etaloning within the detector itself. Etaloning was also evident in the spectral and radiometric characterizations performed on the completed camera. Spectral metrics, including center wavelength and width, are presented here using a moment’s analysis. This better represents the band properties, particularly in bands where fringing is observed, as compared to a full-width at half-maximum determination. It is believed that the MAIA camera has been carefully characterized, and meet its spectral and radiometric requirements.

Harten, Gerard Van↗

Surface Biology and Geology (SBG) Thermal Infrared (TIR) Free -Flyer Concept

Scientists and engineers from the United States and Italy are developing a thermal infrared (TIR) free-flyer concept that forms an essential element of the NASA Surface Biology & Geology (SBG) designated observable and the greater NASA Earth System Observatory (ESO), which also includes observations of aerosols, clouds, convection, and precipitation; mass change; and surface deformation & change.In response to the recommendations from the 2017 National Academies decadal survey for Earth science, NASA initiated the SBG designated observable with five key research and applications focus areas: ecosystems and natural resources, hydrology, weather, climate, and solid Earth. SBG includes spaceborne measurements of hyperspectral imagery in the visible to shortwave infrared (0.4-2.5 um) and multispectral imagery in the mid and thermal infrared (3-12 um) that provide the remote sensing data needed to inform each research and applications area. High-level TIR data products include Earth surface temperature & emissivity, evapotranspiration, substrate composition, volcanic plumes, and high-temperature features. While the science, applications, and technology build on prior mission studies conducted for more than a decade, it has only been recently that a joint team of scientists and engineers from the NASA Jet Propulsion Laboratory (JPL), Agenzia Spaziale Italiana (ASI), Istituto Nazionale Geofisica e Volcanologia (INGV), and the Istituto Nazionale Astrofisica (INAF) have developed a compelling concept for a TIR free-flyer. In this concept, the TIR instrument is an eight-band radiometer. Seven of the bands are between 3 and 12 um with an additional band at 1.65 um. The instrument’s 68.8 deg total viewing angle and the free-flyer’s 665 km operational altitude results in a ground sampling distance (GSD) of <60 m at nadir, produces a swath width of 935 km, and allows for a 2-3-day revisit time. A two-band visible and near infrared (VNIR) camera, with <30 m GSD at nadir and 935 km swath width, will complement the TIR instrument. VNIR high-level data products include top & bottom of atmosphere reflectance and normalized difference vegetation indices (NDVI). The TIR instrument and VNIR camera will be mounted on a PLATiNO+ spacecraft, a multi-application, reconfigurable, and scalable platform. The launcher selected for the TIR free-flyer is the VEGA-C. To maximize the science and applications benefits the SBG-TIR free-flyer team are collaborating with personnel from the ESA Land Surface Temperature Monitoring mission (LSTM) as well individuals from the Thermal Infrared Imaging Satellite for High-resolution Natural resource Assessment (TRISHNA), a joint mission by CNES and ISRO. Pre-Phase A concept studies for the SBG-TIR free-flyer commenced in the spring 2021. This allows for the concept to be refined; for technical risks to be identified and mitigated, as necessary; and strategies for reducing the development schedule to be defined and assessed before conducting a NASA-ASI Mission Concept Review (MCR) in the spring of 2022 and a NASA Key Decision Point-A (KDP-A) as early as the summer of 2022. These are key milestones in being able to launch and begin operating the SBG-TIR free-flyer in the second half of the decade, so that many of the questions posed by the National Academies in the 2017 decadal survey can be answered.

Fabrizia-Buongiorno, Maria↗

Calibration Refinements in Support of MISR

The Multi-angle Imaging SpectroRadiometer (MISR) is one of five instruments on-board the EOSI Terra spacecraft, and has collected science data since March 2000. A multi-angle capability is provided by ninecameras, which view up to 70' forward and aft of the spacecraft track and enable unique geophysical retrievals. Throughout its mission, a calibration team has made periodic refinements to the process used to calibrate MISR. These have resulted in improved absolute, and band and camera-relative calibrations, as well as in derived geophysical data products. Data reprocessing is on-going, such that these refinements also improve previous data acquisitions. The calibration process is believed to be mature at this time, with no other changes anticipated. Bimonthly deployments of the on-board-calibrator continue to monitor instrument response degradations, and provide correction coefficients needed to maintain the accuracy of the radiance products.

refinements↗

Water Detection Based on Color Variation

This software has been designed to detect water bodies that are out in the open on cross-country terrain at close range (out to 30 meters), using imagery acquired from a stereo pair of color cameras mounted on a terrestrial, unmanned ground vehicle (UGV). This detector exploits the fact that the color variation across water bodies is generally larger and more uniform than that of other naturally occurring types of terrain, such as soil and vegetation. Non-traversable water bodies, such as large puddles, ponds, and lakes, are detected based on color variation, image intensity variance, image intensity gradient, size, and shape. At ranges beyond 20 meters, water bodies out in the open can be indirectly detected by detecting reflections of the sky below the horizon in color imagery. But at closer range, the color coming out of a water body dominates sky reflections, and the water cue from sky reflections is of marginal use. Since there may be times during UGV autonomous navigation when a water body does not come into a perception system s field of view until it is at close range, the ability to detect water bodies at close range is critical. Factors that influence the perceived color of a water body at close range are the amount and type of sediment in the water, the water s depth, and the angle of incidence to the water body. Developing a single model of the mixture ratio of light reflected off the water surface (to the camera) to light coming out of the water body (to the camera) for all water bodies would be fairly difficult. Instead, this software detects close water bodies based on local terrain features and the natural, uniform change in color that occurs across the surface from the leading edge to the trailing edge.

Rankin, Arturo L.↗

Prediction of Viking lander camera image quality

Formulations are presented that permit prediction of image quality as a function of camera performance, surface radiance properties, and lighting and viewing geometry. Predictions made for a wide range of surface radiance properties reveal that image quality depends strongly on proper camera dynamic range command and on favorable lighting and viewing geometry. Proper camera dynamic range commands depend mostly on the surface albedo that will be encountered. Favorable lighting and viewing geometries depend mostly on lander orientation with respect to the diurnal sun path over the landing site, and tend to be independent of surface albedo and illumination scattering function. Side lighting with low sun elevation angles (10 to 30 deg) is generally favorable for imaging spatial details and slopes, whereas high sun elevation angles are favorable for measuring spectral reflectances.

Huck, F. O.↗

Hypersonic Laminar Boundary Layer Velocimetry with Discrete Roughness on a Flat Plate

Laminar boundary layer velocity measurements are made on a 10-degree half-angle wedge in a Mach 10 flow. Two types of discrete boundary layer trips were used to perturb the boundary layer gas. The first was a 2-mm tall, 4-mm diameter cylindrical trip. The second was a scaled version of the Orbiter Boundary Layer Transition (BLT) Detailed Test Objective (DTO) trip. Both 1-mm and 2.5-mm tall BLT DTO trips were tested. Additionally, side-view and plan-view axial boundary layer velocity measurements were made in the absence of these tripping devices. The free-stream unit Reynolds numbers tested for the cylindrical trips were 1.7x10(exp 6)/m and 3.3x10(exp 6)/m. The free-stream unit Reynolds number tested for the BLT DTO trips was 1.7x10(exp 6)/m. The angle of attack was kept at approximately 5-degrees for most of the tests resulting in a Mach number of approximately 8.3. These combinations of unit Reynolds numbers and angle of attack resulted in laminar flowfields. To study the precision of the measurement technique, the angle of attack was varied during one run. Nitric-oxide (NO) molecular tagging velocimetry (MTV) was used to obtain averaged axial velocity values and associated uncertainties. These uncertainties are as low as 20 m/s. An interline, progressive scan CCD camera was used to obtain separate images of the initial reference and shifted NO molecules that had been tagged by the laser. The CCD configuration allowed for sub-microsecond sequential acquisition of both images. The maximum planar spatial resolution achieved for the side-view velocity measurements was 0.07-mm in the wall-normal direction by 1.45-mm in the streamwise direction with a spatial depth of 0.5-mm. For the plan-view measurements, the maximum planar spatial resolution in the spanwise and streamwise directions was 0.69-mm by 1.28-mm, respectively, with a spatial depth of 0.5-mm. Temperature sensitive paint (TSP) measurements are provided to compliment the velocity data and to provide further insight into the behavior of the boundary layers. The experiments were performed at the NASA Langley Research Center 31-Inch Mach 10 Air tunnel.

Bathel, Brett↗

Side-Looking Viewer for Crevices

Side-looking optical viewer inserted into gap 1 mm wide to depth of 10 cm. Instrument allows human observer to inspect small crevices from comfortable viewing angle. Small mirror atop pair of thin, flat legs inserted into gap. Mirror reflects image of gap wall or other object into microscope, which magnifies image 20 times. Quartz/halogen lamp in separate unit provides light to illuminate gap via optical-fiber bundle. Observer looks directly through microscope or attaches photographic or video camera without disturbing setup.

Hagen, G. R.↗

Acquisition of spectral reflectance data using an artificial source of hemispherical illumination

An integrating hemisphere illumination system has been developed to facilitate the collection of spectral reflectance factor measurements of targets of interest in a laboratory environment. One of the most significant advantages associated with such an illumination source is that repeated measurements can be made over an extended period of time, for a variety of targets, under nearly identical illumination and viewing angle conditions. The illumination system consists of a 76 cm (30 in.) aluminum hemisphere coated internally with barium sulfate paint. Illumination is provided by sixteen 62 watt quartz halogen bulbs with tungsten filaments. A simple metal structure has been developed to hold the hemisphere and all peripheral equipment, such as spectrometers, radiometers, and cameras, in place during data collection. The entire set up can be easily disassembled and packed in airline-approved shipping cases to facilitate transportation to laboratory facilities located near any study area. The illumination system is described briefly, and numerous plots of radiance and spectral reflectance are provided to illustrate the performance and utility of the apparatus.

Williams, Darrel L.↗

X-Ray Computed Tomography Monitors Damage in Composites

The NASA Lewis Research Center recently codeveloped a state-of-the-art x-ray CT facility (designated SMS SMARTSCAN model 100-112 CITA by Scientific Measurement Systems, Inc., Austin, Texas). This multipurpose, modularized, digital x-ray facility includes an imaging system for digital radiography, CT, and computed laminography. The system consists of a 160-kV microfocus x-ray source, a solid-state charge-coupled device (CCD) area detector, a five-axis object-positioning subassembly, and a Sun SPARCstation-based computer system that controls data acquisition and image processing. The x-ray source provides a beam spot size down to 3 microns. The area detector system consists of a 50- by 50- by 3-mm-thick terbium-doped glass fiber-optic scintillation screen, a right-angle mirror, and a scientific-grade, digital CCD camera with a resolution of 1000 by 1018 pixels and 10-bit digitization at ambient cooling. The digital output is recorded with a high-speed, 16-bit frame grabber that allows data to be binned. The detector can be configured to provide a small field-of-view, approximately 45 by 45 mm in cross section, or a larger field-of-view, approximately 60 by 60 mm in cross section. Whenever the highest spatial resolution is desired, the small field-of-view is used, and for larger samples with some reduction in spatial resolution, the larger field-of-view is used.

Baaklini, George Y.↗

Aspects of Voyager photogrammetry

In January 1986, Voyager 2 took a series of pictures of Uranus and its satellites with the Imaging Science System (ISS) on board the spacecraft. Based on six stereo images from the ISS narrow-angle camera, a topographic map was compiled of the Southern Hemisphere of Miranda, one of Uranus' moons. Assuming a spherical figure, a 20-km surface relief is shown on the map. With three additional images from the ISS wide-angle camera, a control network of Miranda's Southern Hemisphere was established by analytical photogrammetry, producing 88 ground points for the control of multiple-model compilation on the AS-11AM analytical stereoplotter. Digital terrain data from the topographic map of Miranda have also been produced. By combining these data and the image data from the Voyager 2 mission, perspective views or even a movie of the mapped area can be made. The application of these newly developed techniques to Voyager 1 imagery, which includes a few overlapping pictures of Io and Ganymede, permits the compilation of contour maps or topographic profiles of these bodies on the analytical stereoplotters.

Wu, Sherman S. C.↗