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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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NASA NTRS2007

The In-flight Spectroscopic Performance of the Swift XRT CCD Camera During 2006-2007

The Swift X-ray Telescope focal plane camera is a front-illuminated MOS CCD, providing a spectral response kernel of 135 eV FWHM at 5.9 keV as measured before launch. We describe the CCD calibration program based on celestial and on-board calibration sources, relevant in-flight experiences, and developments in the CCD response model. We illustrate how the revised response model describes the calibration sources well. Comparison of observed spectra with models folded through the instrument response produces negative residuals around and below the Oxygen edge. We discuss several possible causes for such residuals. Traps created by proton damage on the CCD increase the charge transfer inefficiency (CTI) over time. We describe the evolution of the CTI since the launch and its effect on the CCD spectral resolution and the gain.

Godet, O.↗
NASA NTRS2008

Neutron Imaging Camera

The Neutron Imaging Camera (NIC) is based on the Three-dimensional Track Imager (3DTI) technology developed at GSFC for gamma-ray astrophysics applications. The 3-DTI, a large volume time-projection chamber, provides accurate, approximately 0.4 mm resolution, 3-D tracking of charged particles. The incident direction of fast neutrons, En > 0.5 MeV, are reconstructed from the momenta and energies of the proton and triton fragments resulting from (sup 3)He(n,p) (sup 3)H interactions in the 3-DTI volume. The performance of the NIC from laboratory and accelerator tests is presented.

Hunter, Stanley↗
NASA NTRS2008

Lessons Learned from the Wide Field Camera 3 TV1 and TV2 Thermal Vacuum Test Campaigns

The Wide Field Camera 3 (WFC3) instrument has undergone two complete thermal vacuum tests (TV1 and TV2), during which valuable lessons were learned regarding test configuration, test execution, model capabilities, and modeling practices. The very complex thermal design of WFC3 produced a number of challenging aspects to ground testing with numerous ThermoElectric Coolers and heat pipes, not all of which were functional. Lessons learned during TV1 resulted in significant upgrades to the model capabilities and a change in the test environment approach for TV2. These upgrades proved invaluable during TV2 when pretest modeling assumptions proved to be false. Each of the lessons learned relate to one of two following broad statements: 1. Ensure the design can be tested and that the effect of non-flight like conditions is well understood, particularly with respect to non passive devices (TECs, Heat Pipes, etc) 2. Ensure that the model is sufficiently detailed and is capable of predicting off-nominal behavior and the power dissipation of any thermal devices, especially TECs This paper outlines a number of the lessons learned over these two test campaigns with respect to the thermal design, model, and test configuration and presents recommendations for future tests.

Peabody, Hume↗
NASA NTRS2008

Neutron Imaging Camera

We describe the Neutron Imaging Camera (NIC) being developed for DTRA applications by NASA/GSFC and NSWC/Carderock. The NIC is based on the Three-dimensional Track Imager (3-DTI) technology developed at GSFC for gamma-ray astrophysics applications. The 3-DTI, a large volume time-projection chamber, provides accurate, approximately 0.4 mm resolution. 3-D tracking of charged particles. The incident direction of fast neutrons, E(sub N) > 0.5 MeV. arc reconstructed from the momenta and energies of the proton and triton fragments resulting from 3He(n,p)3H interactions in the 3-DTI volume. We present angular and energy resolution performance of the NIC derived from accelerator tests.

Hunter, Stanley D.↗
NASA NTRS2008

Digital X-ray camera for quality evaluation three-dimensional topographic reconstruction of single crystals of biological macromolecules

The present invention provides a digital topography imaging system for determining the crystalline structure of a biological macromolecule, wherein the system employs a charge coupled device (CCD) camera with antiblooming circuitry to directly convert x-ray signals to electrical signals without the use of phosphor and measures reflection profiles from the x-ray emitting source after x-rays are passed through a sample. Methods for using said system are also provided.

Borgstahl, Gloria↗
NASA NTRS2009

In-flight Performance of the Detectors on HST/Wide Field Camera 3

Wide Field Camera 3 (WFC3) is a powerful new imager recently installed on the Hubble Space Telescope during Servicing Mission 4. WFC3 covers wavelengths from the near UV (200nm) to the near infrared (out to 1.7microns), in two channels. The UV/visible (UVIS) channel utilizes two low-noise, UV-enhanced 2Kx4K CCD detectors from e2v, while the IR channel incorporates a 1Kx1K 1.7micron cutoff HgCdTe array, custom-developed for the WFC3 program by Teledyne. We report here on the performance of the detectors in-flight as observed in this summer's Servicing Mission Orbital Verification program.

Kimble, Randy↗
NASA NTRS2009

A Real-Time Microwave Camera at 24 GHz (K-Band}

The objective is to design and build a real-time microwave imaging system (i.e., camera) Microwave imaging offers tremendous potential in many applications: a) Inspection of low-loss composites, radomes, etc.; b) Detection and evaluation of corrosion under paint; c) Security, contraband detection. Raster scanning is slow and requires bulky mechanical systems. A real-time and portable imaging system can be extremely useful for rapid nondestructive testing of large structures.

Ghasr, M. T.↗
NASA NTRS2009

A Powerful New Imager for HST: Performance and Early Science Results from Wide Field Camera 3

Wide Field Camera 3 (WFC3) was installed into the Hubble Space Telescope during the highly successful Servicing Mission 4 in May, 2009. WFC3 offers sensitive, high resolution imaging over a broad wavelength range from the near UV through the visible to the near IR (200nm - 1700nm). Its capabilities in the near UV and near IR ends of that range represent particularly large advances vs. those of previous HST instruments. In this talk, I will review the purpose and design of the instrument, describe its performance in flight, and highlight some of the initial scientific results from the instrument, including its use in deep infrared surveys in search of galaxies at very high redshift, in investigations of the global processes of star formation in nearby galaxies, and in the study of the recent impact on Jupiter.

Kimble, Randy↗
NASA NTRS2007

Solutions Network Formulation Report. Reducing Light Pollution in U.S. Coastal Regions Using the High Sensitivity Cameras on the SAC-C and Aquarius/SAC-D Satellites

Light pollution has significant adverse biological effects on humans, animals, and plants and has resulted in the loss of our ability to view the stars and planets of the universe. Over half of the U.S. population resides in coastal regions where it is no longer possible to see the stars and planets in the night sky. Forty percent of the entire U.S. population is never exposed to conditions dark enough for their eyes to convert to night vision capabilities. In coastal regions, urban lights shine far out to sea where they are augmented by the output from fishing boat, cruise ship and oil platform floodlights. The proposed candidate solution suggests using HSCs (high sensitivity cameras) onboard the SAC-C and Aquarius/SAC-D satellites to quantitatively evaluate light pollution at high spatial resolution. New products modeled after pre-existing, radiance-calibrated, global nighttime lights products would be integrated into a modified Garstang model where elevation, mountain screening, Rayleigh scattering, Mie scattering by aerosols, and atmospheric extinction along light paths and curvature of the Earth would be taken into account. Because the spatial resolution of the HSCs on SAC-C and the future Aquarius/SAC-D missions is greater than that provided by the DMSP (Defense Meteorological Satellite Program) OLS (Operational Linescan System) or VIIRS (Visible/Infrared Imager/Radiometer Suite), it may be possible to obtain more precise light intensity data for analytical DSSs and the subsequent reduction in coastal light pollution.

Andrews, Jane C.↗
NASA NTRS2010

Data Collected During the Post-Flight Survey of Micrometeoroid and Orbital Debris Impact Features on the Hubble Wide Field Planetary Camera 2

Over a period of five weeks during the summer of 2009, personnel from the NASA's Orbital Debris Program Office and Meteoroid Environment Office performed a post-flight examination of the Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC-2) radiator. The objective was to record details about all micrometeoroid and orbital debris (MMOD) impact features with diameters of 300 micron and larger. The WFPC-2 was located in a clean room at NASA's Goddard Space Flight Center. Using a digital microscope, the team examined and recorded position, diameter, and depth information for each of 685 craters. Taking advantage of the digital microscope's data storage and analysis features, the actual measurements were extracted later from the recorded images, in an office environment at the Johnson Space Center. Measurements of the crater include depth and diameter. The depth was measured from the undisturbed paint surface to the deepest point within the crater. Where features penetrate into the metal, both the depth in metal and the paint thickness were measured. In anticipation of hypervelocity tests and simulations, several diameter measurements were taken: the spall area, the area of any bare metal, the area of any discolored ("burned") metal, and the lips of the central crater. In the largest craters, the diameter of the crater at the surface of the metal was also measured. The location of each crater was recorded at the time of inspection. This paper presents the methods and results of the crater measurement effort, including the size and spatial distributions of the impact features. This effort will be followed by taking the same measurements from hypervelocity impact targets simulating the WFPC-2 radiator. Both data sets, combined with hydrocode simulation, will help validate or improve the MMOD environment in low Earth orbit.

Opiela, J. N.↗
NASA NTRS2010

The Fifteen-Year Attitude History of the Wide Field Planetary Camera 2 Radiator and Collection Efficiencies for Micrometeoroids and Orbital Debris

An examination of the Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC-2) radiator assembly was conducted at NASA Goddard Space Flight Center (GSFC) during the summer of 2009. Immediately apparent was a distinct biasing of the largest 45 impact features towards one side of the radiator, in contrast to an approximately uniform distribution of smaller impacts. Such a distribution may be a consequence of the HST s attitude history and pointing requirements for the cold radiator, or of environmental effects, such as an anisotropic distribution of the responsible population in that size regime. Understanding the size-dependent spatial distribution of impact features is essential to the general analysis of these features. We have obtained from GSFC a 15 minute temporal resolution record of the state vector (Earth Centered Inertial position and velocity) and HST attitude, consisting of the orientation of the velocity and HST-sun vectors in HST body coordinates. This paper reviews the actual state vector and attitude history of the radiator in the context of the randomly tumbling plate assumption and assesses the statistical likelihood (or collection efficiency) of the radiator for the micrometeoroid and orbital debris environments. The NASA Marshall Space Flight Center s Meteoroid Environment Model is used to assess the micrometeoroid component. The NASA Orbital Debris Engineering Model (ORDEM) is used to model the orbital debris component. Modeling results are compared with observations of the impact feature spatial distribution, and the relative contribution of each environmental component are examined in detail.

Anz-Meador, Phillip D.↗
NASA NTRS2007

Metrology Camera System Using Two-Color Interferometry

A metrology system that contains no moving parts simultaneously measures the bearings and ranges of multiple reflective targets in its vicinity, enabling determination of the three-dimensional (3D) positions of the targets with submillimeter accuracy. The system combines a direction-measuring metrology camera and an interferometric range-finding subsystem. Because the system is based partly on a prior instrument denoted the Modulation Sideband Technology for Absolute Ranging (MSTAR) sensor and because of its 3D capability, the system is denoted the MSTAR3D. Developed for use in measuring the shape (for the purpose of compensating for distortion) of large structures like radar antennas, it can also be used to measure positions of multiple targets in the course of conventional terrestrial surveying. A diagram of the system is shown in the figure. One of the targets is a reference target having a known, constant distance with respect to the system. The system comprises a laser for generating local and target beams at a carrier frequency; a frequency shifting unit to introduce a frequency shift offset between the target and local beams; a pair of high-speed modulators that apply modulation to the carrier frequency in the local and target beams to produce a series of modulation sidebands, the highspeed modulators having modulation frequencies of FL and FM; a target beam launcher that illuminates the targets with the target beam; optics and a multipixel photodetector; a local beam launcher that launches the local beam towards the multi-pixel photodetector; a mirror for projecting to the optics a portion of the target beam reflected from the targets, the optics being configured to focus the portion of the target beam at the multi-pixel photodetector; and a signal-processing unit connected to the photodetector. The portion of the target beam reflected from the targets produces spots on the multi-pixel photodetector corresponding to the targets, respectively, and the signal-processing unit centroids the spots to determine bearings of the targets, respectively. As the spots oscillate in intensity because they are mixed with the local laser beam that is flood illuminating the focal plane, the phase of oscillation of each spot is measured, the phase of sidebands in the oscillation of each spot being proportional to a distance to the corresponding target relative to the reference target A.

Dubovitsky, Serge↗
NASA NTRS2006

Lightweight Electronic Camera for Research on Clouds

"Micro-CPI" (wherein "CPI" signifies "cloud-particle imager") is the name of a small, lightweight electronic camera that has been proposed for use in research on clouds. It would acquire and digitize high-resolution (3- m-pixel) images of ice particles and water drops at a rate up to 1,000 particles (and/or drops) per second.

Lawson, Paul↗
NASA NTRS2010

Cosmic Infrared Background Fluctuations in Deep Spitzer Infrared Array Camera Images: Data Processing and Analysis

This paper provides a detailed description of the data reduction and analysis procedures that have been employed in our previous studies of spatial fluctuation of the cosmic infrared background (CIB) using deep Spitzer Infrared Array Camera observations. The self-calibration we apply removes a strong instrumental signal from the fluctuations that would otherwise corrupt the results. The procedures and results for masking bright sources and modeling faint sources down to levels set by the instrumental noise are presented. Various tests are performed to demonstrate that the resulting power spectra of these fields are not dominated by instrumental or procedural effects. These tests indicate that the large-scale ([greater, similar]30') fluctuations that remain in the deepest fields are not directly related to the galaxies that are bright enough to be individually detected. We provide the parameterization of these power spectra in terms of separate instrument noise, shot noise, and power-law components. We discuss the relationship between fluctuations measured at different wavelengths and depths, and the relations between constraints on the mean intensity of the CIB and its fluctuation spectrum. Consistent with growing evidence that the [approx]1-5 [mu]m mean intensity of the CIB may not be as far above the integrated emission of resolved galaxies as has been reported in some analyses of DIRBE and IRTS observations, our measurements of spatial fluctuations of the CIB intensity indicate the mean emission from the objects producing the fluctuations is quite low ([greater, similar]1 nW m-2 sr-1 at 3-5 [mu]m), and thus consistent with current [gamma]-ray absorption constraints. The source of the fluctuations may be high-z Population III objects, or a more local component of very low luminosity objects with clustering properties that differ from the resolved galaxies. Finally, we discuss the prospects of the upcoming space-based surveys to directly measure the epochs inhabited by the populations producing these source-subtracted CIB fluctuations, and to isolate the individual fluxes of these populations.

Arendt, Richard↗
NASA NTRS2010

In-Flight Performance of Wide Field Camera 3

Wide Field Camera 3 (WFC3), a powerful new UVNisible/IR imager, was installed into HST during Servicing Mission 4. After a successful commissioning in the Servicing Mission Orbital Verification program, WFC3 has been engaged in an exciting program of scientific observations. I review here the in-flight scientific performance of the instrument, addressing such topics as image quality, sensitivity, detector performance, and stability.

Kimble, Randy↗
NASA NTRS2011

Color camera computed tomography imaging spectrometer for improved spatial-spectral image accuracy

Computed tomography imaging spectrometers ("CTIS"s) having color focal plane array detectors are provided. The color FPA detector may comprise a digital color camera including a digital image sensor, such as a Foveon X3.RTM. digital image sensor or a Bayer color filter mosaic. In another embodiment, the CTIS includes a pattern imposed either directly on the object scene being imaged or at the field stop aperture. The use of a color FPA detector and the pattern improves the accuracy of the captured spatial and spectral information.

Wilson, Daniel W.↗
NASA NTRS2011

RATIR: Reionization and Transients Infra-Red Camera. A New Instrument to Identify High Red-Shift GRBs

We are currently constructing the cryogenic infrared portion of the RATIR instrument at NASA's Goddard Space Flight Center (GSFC) in collaboration with University of California, Berkeley (UCB) and The University of Mexico (UNAM). The infrared instrument will consist of two 2048x2048 Hawaii 2RG detectors, one on axis and one off axis using diachronic. The detectors will be operated using state-of-the-art Teledyne SIDECAR (System Image, Digitizing, Enhancing, Controlling, And Retrieving) ASICs (Application- Specific Integrated Circuits) similar to NIRSpec on JWST. The visible portion of the instrument is currently being developed at UCB consisting of two CCD imagining cameras. Once completed, the two sections will be integrated into the RATIR instrument. Mounted on a dedicated, fully-automated 1.5-m telescope, the instrument will provide rapid (<10 min) identification of VHR GRBs allowing high-resolution spectroscopic follow-up observations with large aperture telescopes possible. The hosting Observatorio Astronomico Nacional of the Universidad Nacional Autonoma de Mexico (UNAM), located on the Sierra de San Pedro Martir in Baja California, Mexico, provides great seeing (-1 aresec), good weather, dark skies, and significant sky coverage so that RATIR will detect a significant number of Swift afterglows. While not all GRBs will be at high red shifts, the resulting light curves, combined with X-ray/UV observations, will address several open questions, including the nature of both "dark GRBs" and the GRB emission mechanism.

Rapchun, David A.↗
NASA NTRS2011

O-6 Optical Property Degradation of the Hubble Space Telescope's Wide Field Camera-2 Pick Off Mirror

Degradation in the performance of optical components can be greatly affected by exposure to the space environment. Many factors can contribute to such degradation including surface contaminants; outgassing; vacuum, UV, and atomic oxygen exposure; temperature cycling; or combinations of parameters. In-situ observations give important clues to degradation processes, but there are relatively few opportunities to correlate those observations with post-flight ground analyses. The return of instruments from the Hubble Space Telescope (HST) after its final servicing mission in May 2009 provided such an opportunity. Among the instruments returned from HST was the Wide-Field Planetary Camera-2 (WFPC-2), which had been exposed to the space environment for 16 years. This work focuses on the identifying the sources of degradation in the performance of the Pick-off mirror (POM) from WFPC-2. Techniques including surface reflectivity measurements, spectroscopic ellipsometry, FTIR (and ATR-FTIR) analyses, SEM/EDS, X-ray photoelectron spectroscopy (XPS) with and without ion milling, and wet and dry physical surface sampling were performed. Destructive and contact analyses took place only after completion of the non-destructive measurements. Spectroscopic ellipsometry was then repeated to determine the extent of contaminant removal by the destructive techniques, providing insight into the nature and extent of polymerization of the contaminant layer.

McNamara, Karen M.↗