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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 559 records · Page 31

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NASA NTRS1979

Space telescope, a long-life free flyer

The paper describes NASA's Space Telescope (ST) adapted to Shuttle capabilities for launch and retrieval which utilizes the full Shuttle cargo bay space available for payloads and can be returned to the ground for refurbishment. Its objective is to maximize ST's productive lifetime, to probe the universe, and to analyze light from energy sources which cannot be studied by ground-based telescopes. The Shuttle orbiting lifetime will be extended to at least five years, and scientific instruments or failed spacecraft components will be replaced on-orbit. The ST will be returned to earth for major overhauls, refurbished, and relaunched. In summary, the Shuttle will allow space astronomy to be accomplished in the usual manner - by observing, adjusting, changing detectors, and reobserving. The support systems module, the optical telescope assembly, scientific instruments, including the wide field/planetary camera, the faint object spectrograph and the high speed photometer are described.

Field, E. L.↗

NASA NTRS1980

Superposition of supernovae remnant imagery

The superposition of the X-ray, optical, and radio imagery of supernova remnants in the Cygnus Loop region is described. The radio data of the region was obtained using the Westerbork interferometer, and the optical image was recorded by the NASA Wide Field Camera. The X-ray imagery was obtained using the High Resolution Imager. The mechanisms by which the supernova ejecta and the swept-up material shock the interstellar medium are studied by the resampling of the imagery onto a common celestial grid. The initial results indicate a radio arc in the northeastern portion of the region that is along the faintest outermost filaments, and a separate radio arc along the brightest filaments.

Henden, A. A.↗

NASA NTRS1981

The International Ultraviolet Explorer

The instrumentation and functioning of the IUE are discussed. The design of the telescope, fine error sensors, echelle spectrographs, and television cameras, as well as their integration, is described. The optical characteristics of the IUE are listed and the schematic arrangement of the detector is depicted. Sources of background noise are assessed, including the thermionic effects in the UV converters and television tubes, radiation from the earth's trapped electron belts, wide angle white light scattering from the earth and sun, scattering of dispersed light caused by low dispersion gratings, photometric calibration, and photometric stability. IUE sensitivity changes during the first three years of operation are shown together with sensitivity curves for short and long wavelengths. Modes of wavelength determination are considered.

Boggess, A.↗

NASA NTRS1989

White cell design considerations

The White cell is a unit-magnification image relay system consisting of three noncoaxial spherical mirrors of equal curvature. The cell is used to provide a long optical path in a relatively small physical space. Multiple reflections are used, in a manner similar to a unstable laser resonator. A particular application is an optical delay line on the input of a streak camera to allow for the finite triggering time of the sweep start. This paper addresses the first- and third-order properties of the White cell. A displacement sensitivity analysis is included.

Hannan, Paul↗

NASA NTRS1990

Exploring the Universe with the Hubble Space Telescope

A general overview is given of the operations, engineering challenges, and components of the Hubble Space Telescope. Deployment, checkout and servicing in space are discussed. The optical telescope assembly, focal plane scientific instruments, wide field/planetary camera, faint object spectrograph, faint object camera, Goddard high resolution spectrograph, high speed photometer, fine guidance sensors, second generation technology, and support systems and services are reviewed.

Source record↗

NASA NTRS1992

Investigation of solar active regions at high resolution by balloon flights of the solar optical universal polarimeter, definition phase

The definition phase of a scientific study of active regions on the sun by balloon flight of a former Spacelab instrument, the Solar Optical Universal Polarimeter (SOUP) is described. SOUP is an optical telescope with image stabilization, tunable filter and various cameras. After the flight phase of the program was cancelled due to budgetary problems, scientific and engineering studies relevant to future balloon experiments of this type were completed. High resolution observations of the sun were obtained using SOUP components at the Swedish Solar Observatory in the Canary Islands. These were analyzed and published in studies of solar magnetic fields and active regions. In addition, testing of low-voltage piezoelectric transducers was performed, which showed they were appropriate for use in image stabilization on a balloon.

Tarbell, Theodore D.↗

NASA NTRS1993

Subpixel Resolution In Depth Perceived Via 3-D Television

Report describes experiment in which two black vertical bars on featureless white background placed near intersection of optical axes of two charge-coupled-device video cameras positioned to give stereoscopic views. Trained human observers found to perceive depths at subpixel resolutions in stereoscopic television images. This finding significant for remote stereoscopic monitoring, expecially during precise maneuvers of remotely controlled manipulators. Also significant for research in processing of visual information by human brain.

Diner, Daniel B.↗

NASA NTRS1993

Telescope pointing for GOPEX

In order for photons emitted by the GOPEX lasers to be detected by Galileo's camera, the telescopes at Table Mountain Observatory and Starfire Optical Range had to be pointed in the right direction within a tolerance less than the beam divergence. At both sites nearby stars were used as pointing references. The technical challenge was to ensure that the transmission direction and the star positions were specified in exactly the same coordinate system; given this assurance, neither the uncertainty in the star catalog positions nor the difficulty in offset pointing was expected to exceed the pointing error budget. The correctness of the pointing scheme was verified by the success of GOPEX.

Owen, W. M., Jr.↗

NASA NTRS1999

AFM Studies of Lunar Soils and Application to the Mars 2001 Mission

The upcoming Mars 01 mission will carry an Atomic Force Microscope (AFM) as part of the Mars Environmental Compatibility Assessment (MECA) instrument. By operating in a tapping mode, the AFM is capable of sub-nanometer resolution in three dimensions and can distinguish between substances of different compositions by employing phase contrast imaging. To prepare for the Mars 01 mission, we are testing the AFM on a lunar soil to determine its ability to define particle shapes and sizes and grain-surface textures. The test materials are from the Apollo 17 soil 79221, which is a mixture of agglutinates, impact and volcanic beads, and mare and highland rock and mineral fragments. The majority of the lunar soil particles are less than 100 microns in size, comparable to the sizes estimated for martian dust. We have used the AFM to examine several different soil particles at various resolutions. The instrument has demonstrated the ability to identify parallel ridges characteristic of twinning on a 150 micron plagioclase feldspar particle. Extremely small (10-100 nanometer) adhering particles are visible on the surface of the feldspar grain, and they appear elongate with smooth surfaces. Phase contrast imaging of the nanometer particles shows several compositions to be present. When the AFM was applied to a 100 micron glass spherule, it was possible to define an extremely smooth surface; this is in clear contrast to results from a basalt fragment which exhibited a rough surface texture. Also visible on the surface of the glass spherule were chains of 100 nanometer and smaller impact melt droplets. For the '01 Mars mission, the AFM is intended to define the size and shape distributions of soil particles, in combination with the NMCA optical microscope system and images from the Robot Arm Camera (RAC). These three data sets will provide a means of assessing potentially hazardous soil and dust properties. The study that we have conducted on the lunar soils now suggests that the NMCA experiment will be able to define grain transport and weathering processes. For example, it should be possible to determine if Martian grains have been subjected to aeolian or water transport, volcanic activity, impact melting processes, in-situ weathering, and a host of other processes. Additionally, textural maturity could be assessed (via freshness and form of fracture patterns and grain shapes). Thus, the AFM has the potential to shed new light on Martian surface processes by adding the submicroscopic dimension to planetary investigations.

Weitz, C. M.↗

NASA NTRS2002

Development of Infrared Phase Closure Capability in the Infrared-Optical Telescope Array (IOTA)

We completed all major fabrication and testing for the third telescope and phase-closure operation at the Infrared-Optical Telescope Array (IOTA) during this period. In particular we successfully tested the phase-closure operation, using a laboratory light source illuminating the full delay-line optical paths, and using an integrated-optic beam combiner coupled to our Picnic-detector camera. This demonstration is an important and near-final milestone achievement. As of this writing, however, several tasks yet remain, owing to development snags and weather, so the final proof of success, phase-closure observation of a star, is now expected to occur in early 2002, soon after this report has been submitted.

Traub, Wesley A.↗

NASA NTRS1999

Hyperspectral Thermal Fabry-Perot Modeling

Fabry-Perot interferometer are simple elegant, tunable filters that can be used to make compact hyperspectral thermal imaging system. To foster the development of these sensors, software tools for the design and simulation of tunable Fabry-Perot infrared imagers have been developed. The tools are provided at three levels: basic, design, and system. Basic tools describe a nearly ideal Fabry-Perot filter with perfectly flat and parallel mirrors in collimated space. Design tools that take into account non-ideal behavior such as mirror and collimation defects calculate free spectral range, finesse, and spectral width of the interferometer. System tools help analyze an integration of the Fabry-Perot filter into a camera system. They include spectral convolution, first-order optical layout, and an estimation of signal-to-noise ratio. The complete set of tools allows for simulations of system operation and performance with various illumination sources. Spectral images generated in such simulations were used to examine applicability of Fabry-Perot system in remote sensing of atmospheric gases including detection of environmental pollutants and hazardous gases. Different operating conditions and system configurations are presented.

Ryan, Robert↗

NASA NTRSDate not supplied

MISR Camera Geometry Model (MISANCGM_V2)

The CGM dataset is used to describe pointing geometry of the nine MISR cameras. It consists of a set of parameters used in a mathematical expression that gives the pointing direction of an arbitrary pixel in the spacecraft attitude frame of reference. These parameters represent the geometry of the camera system and account for distortions from an ideal optical system..

AM-1↗

NASA NTRS2006

Wavefront Sensing and Control Architecture for the Spherical Primary Optical Telescope (SPOT)

Testbed results are presented demonstrating high-speed image-based wavefront sensing and control for a spherical primary optical telescope (SPOT). The testbed incorporates a phase retrieval camera coupled to a 3-Mirror Vertex testbed (3MV) at the NASA Goddard Space Flight Center. Actuator calibration based on the Hough transform is discussed as well as several supercomputing archtectures for image-based wavefront sensing. Timing results are also presented based on various algorithm implementations using a cluster of 64 TigerShare TSlOl DSP's (digital-signal processors).

Dean, Bruce H.↗

NASA NTRS2013

Common Practice Lightning Strike Protection Characterization Technique to Quantify Damage Mechanisms on Composite Substrates

To support FAA certification airworthiness standards, composite substrates are subjected to lightning direct-effect electrical waveforms to determine performance characteristics of the lightning strike protection (LSP) conductive layers used to protect composite substrates. Test results collected from independent LSP studies are often incomparable due to variability in test procedures & applied practices at different organizations, which impairs performance correlations between different LSP data sets. Under a NASA supported contract, The Boeing Company developed technical procedures and documentation as guidance in order to facilitate a test method for conducting universal common practice lightning strike protection test procedures. The procedures obtain conformity in future lightning strike protection evaluations to allow meaningful performance correlations across data sets. This universal common practice guidance provides the manufacturing specifications to fabricate carbon fiber reinforced plastic (CFRP) test panels, including finish, grounding configuration, and acceptable methods for pretest nondestructive inspection (NDI) and posttest destructive inspection. The test operations guidance elaborates on the provisions contained in SAE ARP5416 to address inconsistencies in the generation of damage protection performance data, so as to provide for maximum achievable correlation across capable lab facilities. In addition, the guidance details a direct effects test bed design to aid in quantification of the multi-physical phenomena surrounding a lightning direct attachment supporting validation data requirements for the development of predictive computational modeling. The lightning test bed is designed to accommodate a repeatable installation procedure to secure the test panel and eliminate test installation uncertainty. It also facilitates a means to capture the electrical waveform parameters in 2 dimensions, along with the mechanical displacement and thermal heating parameters which occur during lightning attachment. Following guidance defined in the universal common practice LSP test documents, protected and unprotected CFRP panels were evaluated at 20, 40 and 100KAmps. This report presents analyzed data demonstrating the scientific usefulness of the common practice approach. Descriptions of the common practice CFRP test articles, LSP test bed fixture, and monitoring techniques to capture the electrical, mechanical and thermal parameters during lightning attachment are presented here. Two methods of measuring the electrical currents were evaluated, inductive current probes and a newly developed fiberoptic sensor. Two mechanical displacement methods were also examined, optical laser measurement sensors and a digital imaging correlation camera system. Recommendations are provided to help users implement the common practice test approach and obtain LSP test characterizations comparable across data sets.

Szatkowski, George N.↗

NASA NTRS2014

Improved Measurement of Ejection Velocities From Craters Formed in Sand

A typical impact crater is formed by two major processes: compression of the target (essentially equivalent to a footprint in soil) and ejection of material. The Ejection-Velocity Measurement System (EVMS) in the Experimental Impact Laboratory has been used to study ejection velocities from impact craters formed in sand since the late 1990s. The original system used an early-generation Charge-Coupled Device (CCD) camera; custom-written software; and a complex, multicomponent optical system to direct laser light for illumination. Unfortunately, the electronic equipment was overtaken by age, and the software became obsolete in light of improved computer hardware.

Cintala, Mark J.↗

NASA NTRS2010

Earth Return Navigation Analysis for Manned Spacecraft Using Optical and Radiometric Measurements

Future manned space missions will travel beyond low Earth orbit with more stringent navigation requirements and fewer navigation resources than used for the Apollo Program of the 1960s. A study has been performed to assess radiometric and optical tracking capabilities necessary to meet nominal and contingency Earth entry flight path angle requirements. Results indicate that 3 tracking stations will be insufficient for meeting nominal entry requirements, while the performance of a 6 station architecture is dependent on the entry geometry. Optical tracking results indicate that a narrow-angle camera is required for satisfying contingency Earth return requirements.

GN&C↗

NASA NTRSDate not supplied

VTXO: Virtual Telescope for X-ray Observations

VTXO is a potential SmallSat precision formation flying mission using an OpticsSat with X-ray Phase Fresnel Lens (PFL) Optics and a DetectorSat with an X-ray camera forming a 1km focal length X-ray telescope with 55 milli-arcsecond(mas) angular resolution and 8 arcsecond FoV. VTXO development was supported under a 2018 NASA Astrophysics Science SmallSat Studies proposal.

John Krizmanic↗

NASA NTRSDate not supplied

Cryogenic High Accuracy Refraction Measurements Capabilities and New FUV Coating Mirror Technology Developments

This talk will emphasize the basic principles of refractive materials used in an optical telescope. In particular, the presentation will describe refractive index measurements that were performed for one of the instruments on the James Webb Space Telescope (JWST). A refractive system design was implemented in the Near-Infrared Camera (NIRCam) which is one of the main instruments on the JWST observatory. This camera was designed to make observations in the infrared part of the optical spectrum, and it is required to operate in a space environment at temperatures as low as 25K. Therefore, it was imperative to know the refractive index at those low cryogenic temperatures for the various glass substrates (ZnSe, LiF and BaF2) used in the system design of NIRCam. These cryogenic index of refraction measurements were carried out by using the world-class refractometer called the Cryogenic High Accuracy Refraction Measuring System (CHARMS) facility that was designed and built at the Goddard Space Flight Center (GSFC) in Greenbelt, MD. In the second part, there will be a discussion of the recent advances on the research and development activities of advanced and new mirror coating technologies that provide high reflectance performance in the far-ultraviolet (FUV) part of the optical spectrum. These new mirror coatings are envisioned for use on the reflecting mirrors of the next mission (beyond JWST) that will focus on astronomical observations in the FUV spectral range to deliver new and exciting discoveries about the origin of the cosmos.

Astronomy↗