Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “optical camera”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

Analysis of the Optical Design for the SAFIR Telescope

SAFIR, the Single Aperture Far Infra Red Observatory, is a very powerful space mission that will achieve background-limited sensitivity in the far infrared-submillimeter spectral region. Many processes of enormous interest to astronomers can best be studied in this wavelength range, but require the demanding combination of high sensitivity, good angular resolution, and spectroscopic capability. SAFIR is a 10m class telescope to offering good angular resolution, cooled to below 5 K in order to achieve background-limited sensitivity, and equipped with a complement of large-format cameras and broadband spectrometers. Successful operation of such a facility is critically dependent on achieving the level of sensitivity expected, but this is rendered difficult by potential pickup from unwanted sources of radiation. This problem is exacerbated by the fact that the emission from the optical system itself is minimal due to its low temperature, thus emphasizing the importance of minimizing pickup from unwanted astronomical sources of radiation, including the emission from dust in our solar system (analogous to the zodiacal light, hence 'zodi'), and the emission from warm dust in the Milky Way (Galactic 'cirrus').

antenna radiation patterns↗
NASA NTRS1988

Optical contamination measurements on early Shuttle missions

Two camera/photometers were included as part of the Induced Environment Contamination Monitor on STS-2,-3,-4, and -9 orbital missions to record photographically Shuttle-induced particulate and background contamination. The cameras collected stereoscopic data continuously during the on-orbit phases of these missions making exposures every 150 s. The results recorded throughout a 32-deg field-of-view indicate high particle concentrations during early mission operations. These decay to a quiescent rate of 500 particles of greater than 10-micron radius observed per orbit. Preliminary size and velocity distributions of measured particles are presented as are measurements of background brightness due to unresolved particles in the visible spectral region.

Clifton, K. Stuart↗
NASA NTRS2003

Search for X-Ray Emission in the Nearest Known Brown Dwarf

The XMM observation were obtained on 2001 January 07-08 for 51767 s. The Optical Monitor (OM) was used with the V filter for 4 exposures of 5000 s each in imaging mode. We used the data given by the OM to confirm the presence of the source in the field of view. The European Photon Imaging Camera (EPIC) MOS 1 and MOS2 were used 48724 s each in prime full window mode with 2.5 s time resolution. The EPIC PN was used 46618 s in prime full window mode with 73.4 ms time resolution. The X-ray source closest to the expected position of our target is offset by delta R.A=2.5 arcsec and delta Dec=-28.37 arcsec. This offset is high in comparison with the 0.4 arcsec observed with the optical data. So at this point we already knew that the target was not detected. To confirm that conclusion, we performed the identification of all X-ray sources in the field of view by comparing source to source our image with the one obtained by Rutledge et al. with Chandra. This allowed us to identify all the X-ray sources in our field of view in an area of 20 arcsec times 10 arcsec centered on the expected coordinates of LP944-20. We were then able to conclude that the target was not detected during this observation. This result allowed us to determine a new and better 3 sigma upper limit of X-Ray emission for this object. We have also derived duty cycles for X-ray flares as a function of X-ray luminosity by comparing the XMM data with Chandra and ROSAT data. One student has been supported with the grant during four months (Herve Bouy). A Sun workstation was purchased for him.

Martin, Eduardo↗
NASA NTRS2006

Dynamic Pupil Masking for Phasing Telescope Mirror Segments

A method that would notably include dynamic pupil masking has been proposed as an enhanced version of a prior method of phasing the segments of a primary telescope mirror. The method would apply, more specifically, to a primary telescope mirror that comprises multiple segments mounted on actuators that can be used to tilt the segments and translate them along the nominal optical axis to affect wavefront control in increments as fine as a fraction of a wavelength of light. An apparatus (see figure) for implementing the proposed method would be denoted a dispersed-fringe-sensor phasing camera system (DPCS). The prior method involves the use of a dispersed-fringe sensor (DFS). The prior method was reported as part of a more comprehensive method in Coarse Alignment of a Segmented Telescope Mirror (NPO-20770), NASA Tech Briefs, Vol. 25, No. 4 (April 2001), page 15a. The pertinent parts of the prior method are the following: The telescope would be aimed at a bright distant point source of light (e.g., a star) and form a broadband image on an imaging detector array placed at the telescope focal plane. The construction and use of a dispersed-fringe sensor would begin with insertion of a grism (a right-angle prism with a transmission grating on the hypotenuse face) into the optical path. With other segments tilted away from the investigating region of the detector, a dispersed-fringe image would be formed by use of a designated reference segment and a selected mirror segment. The modulation period and orientation of the fringe would be analyzed to determine the magnitude and sign of the piston error (displacement along the nominal optical axis) between the two segments. The error would be used to perform a coarse-phase piston adjustment of the affected mirror segment. This determination and removing of piston error is what is meant by phasing as used above. The procedure as described thus far would be repeated until all segments had been phased.

Shi, Fang↗
NASA NTRS1979

Electronic heterodyne recording of interference patterns

An electronic heterodyne technique is being investigated for video (i.e., television rate and format) recording of interference patterns. In the heterodyne technique electro-optic modulation is used to introduce a sinusoidal phase shift between the beams of an interferometer. For phase modulation frequencies between 0.1 and 15 MHz an image dissector camera may be used to scan the resulting temporally modulated interference pattern. Heterodyne detection of the camera output is used to selectively record the interference pattern. An advantage of such synchronous recording is that it permits recording of low-contrast fringes in high ambient light conditions. The application of this technique to the recording of holograms is discussed.

Merat, F. L.↗
NASA NTRS1983

Observations of optical emissions on STS-4

Following the discovery of intense vehicle glow of the Space Shuttle on the STS-3 mission, a new experiment to probe this phenomenon was developed and flown on the Shuttle STS-4 mission. A conventional camera was equipped with an objective transmission grating and several photographic exposures were taken of the Shuttle tail from the aft flight deck window. Vehicle glow surrounding Shuttle surfaces exposed to the ram direction was observed on a long (400 second) exposure. From analysis of the resulting spectral data it appears that the Shuttle glow has a diffuse spectral component in the region 6300 to 8000A. In addition, it has been possible to assess the spectral character of light emitted by the firing of a reaction control system thruster. Our data show that the light emitted from the thruster gases is confined to wavelengths shorter than 7200A.

Mende, S. B.↗
NASA NTRS1961

The TIROS II Radiation Experiment

The TIROS II meteorological satellite was placed into orbit on November 23, 1960. It contains two television cameras and equipment for a family of electromagnetic radiation experiments, including a medium resolution radiometer. The medium resolution radiometer is a cluster of five sensors which have their optical axes inclined 45 deg. to the spin axis of the satellite. The spin of TIROS II provides the scanning motion. The five radiometer channels are sensitive to the following spectral bands: 6 to 6.5; 8 to 12; 0.2 to 6; 8 to 30; and 0.55 to 0.75 microns.

Hanel, R. A.↗
NASA NTRS1994

Hubble Space Telescope Briefing: HST Science Overview

This NASA Kennedy Space Center video release presents a broad overview of the science that is now possible as a result of the servicing of the Hubble Space Telescope (HST). Dr. Ed Weiler (HST Program Scientist, NASA Headquarters), Dr. Dave Leckrone (HST, Senior Project Scientist, Goddard Space Flight Center (GSFC)), Dr. John Trauger (Wide Field Planetary Camera 2 (WFPC2) Principal Investigator, Jet Propulsion Lab. (JPL)), Dr. Chris Burrows (WFPC2 Co-Investigator, Space Telescope Science Inst.(STSci)-European Space Agency (ESA), Jim Crocker ((Corrective Optics Space Telescope Axial Replacement) COSTAR Team Leader, STSci), Dr. Holland Ford (COSTAR Project Scientist, Johns Hopkins Univ., STSci), and Dr. Duccio Machetto (European Space Agency (ESA)) give brief presentations, which feature images of stars and galaxies taken from the ground, from WFPC1 (prior to the servicing mission), and from WFPC2 (after the servicing mission). The main theme of the discussions center around the spherical aberration that was found in the images prior to servicing and the corrected images seen without the aberration following servicing. A question and answer period rounds out the press conference, with questions posed from scientific journalists at GSFC and other NASA centers.

Source record↗
NASA NTRS1999

A New Approach to Measure Contact Angle and Evaporation Rate with Flow Visualization in a Sessile Drop

The contact angle and the spreading process of sessile droplet are very crucial in many technological processes, such as painting and coating, material processing, film-cooling applications, lubrication, and boiling. Additionally, as it is well known that the surface free energy of polymers cannot be directly, measured for their elastic and viscous restraints. The measurements of liquid contact angle on the polymer surfaces become extremely important to evaluate the surface free energy of polymers through indirect methods linked with the contact angle data. Due to the occurrence of liquid evaporation is inevitable, the effects of evaporation on the contact angle and the spreading become very important for more complete understanding of these processes. It is of interest to note that evaporation can induce Marangoni-Benard convection in sessile drops. However, the impacts of the inside convection on the wetting and spreading processes are not clear. The experimental methods used by previous investigators cannot simultaneously measure the spreading process and visualize the convection inside. Based on the laser shadowgraphic system used by the present author, a very simple optical procedure has been developed to measure the contact angle, the spreading speed, the evaporation rate, and to visualize inside convection of a sessile drop simultaneously. Two CCD cameras were used to synchronously record the real-time diameter of the sessile drop, which is essential for determination of both spreading speed and evaporation rate, and the shadowgraphic image magnified by the sessile drop acting as a thin plano-convex lens. From the shadowgraph, the inside convection of the drop can be observed if any and the image outer diameter, which linked to the drop profile, can be measured. Simple equations have been derived to calculate the drop profile, including the instantaneous contact angle, height, and volume of the sessile drop, as well as the evaporation rate. The influence of the inside convection on the wetting and spreading processes can be figured out through comparison of the drop profiles with and without inside convection when the sessile drop is placed at different evaporation conditions.

Zhang, Nengli↗
NASA NTRS2005

High-speed electromechanical chutter for imaging spectrographs

The present invention presents a high-speed electromechanical shutter which has at least two rotary beam choppers that are synchronized using a phase-locked loop electronic control to reduce the duty cycle. These choppers have blade means that can comprise discs or drums, each having about 60 (+/- 15) slots which are from about 0.3 to about 0.8 mm wide and about 5 to about 20 nun long (radially) which are evenly distributed through out 360 deg, and a third rotary chopper which is optically aligned has a small number of slots, such as for example, 1 to 10 slots which are about 1 to about 2 mm wide and about 5 to about 20 mm long (radially). Further the blade means include phase slots that allow the blade means to be phase locked using a closed loop control circuit. In addition, in a preferred embodiment, the system also has a leaf shutter. Thus the invention preferably achieves a gate width of less than about 100 microseconds, using motors that operate at 3000 to 10,OOO rpm, and with a phase jitter of less than about 1.5 microseconds, and further using an aperture with more than about 75% optical transmission with a clear aperture of about 0.8 -10 nun. The system can be synchronized to external sources at 0 6 kHz lasers, data acquisition systems, and cameras.

Quang-Viet Nguyen↗
NASA NTRS1994

Thermal Design of the Cassini Narrow Angle Camera

The Narrow Angle Camera (NAC) is one of two cameras in the Imaging Science Subsystem (ISS) on the Cassini Spacecraft (S/C), the second camera is a Voyager-inherited Wide Angle Camera (WAC). Cassini is currently planned to be launched in October 1997 and will arrive at Saturn for a four year tour in June 2004. The Narrow Angle Optics are a Ritchey Chretien type Optics, has a focal length of 2000 mm, a relative aperture of f/10.5, a spectral range of 200 to 1100 nm, 24 filters, a pixel field of view of 6.0 microradian/pixel, and has a field of view of 3.5 x 3.5 degrees. The sensor is a Charged Couple Device (CCD), 1024 x 1024 pixels with a pixel size of 12 x 12 um, a full well greater than 50,000 e-, on chip processing of up to 800,000 e- pixel summation, a dark current of less than 0.1 e-/pixel/sec at operating temperature, and a charge transfer efficiency of 0.99999 at operating temperature...

Hoffman, Pamela↗
NASA NTRS2014

NASA's Newest Orbital Debris Ground-based Telescope Assets: MCAT and UKIRT

NASA's Orbital Debris Program Office (ODPO) will break ground on Ascension Island in 2014 to build the newest optical (0.30 - 1.06 micrometers) ground-based telescope asset dedicated to the study of orbital debris. The Meter Class Autonomous Telescope (MCAT) is a 1.3m optical telescope designed to track objects in orbits ranging from Low Earth Orbit (LEO) to Geosynchronous Earth Orbit (GEO). Ascension Island is located in the South Atlantic Ocean, offering longitudinal sky coverage not afforded by the Ground-based Electro-Optical Deep Space Surveillance (GEODSS) network. With a fast-tracking dome, a suite of visible wide-band filters, and a time-delay integration (TDI) capable camera, MCAT is capable of multiple observing modes ranging from tracking cataloged debris targets to surveying the overall debris environment. Access to the United Kingdom Infrared Telescope (UKIRT) will extend our spectral coverage into the near- (0.8-5 micrometers) and mid- to far-infrared (8-25 micrometers) regime. UKIRT is a 3.8m telescope located on Mauna Kea on the Big Island of Hawaii. At nearly 14,000-feet and above the atmospheric inversion layer, this is one of the premier astronomical sites in the world and is an ideal setting for an infrared telescope. An unprecedented one-third of this telescope's time has been allocated to collect orbital debris data for NASA's ODPO over a 2-year period. UKIRT has several instruments available to obtain low-resolution spectroscopy in both the near-IR and the mid/far-IR. Infrared spectroscopy is ideal for constraining the material types, albedos and sizes of debris targets, and potentially gaining insight into reddening effects caused by space weathering. In addition, UKIRT will be used to acquire broadband photometric imaging at GEO with the Wide Field Camera (WFCAM) for studying known objects of interest as well as collecting data in survey-mode to discover new targets. Results from the first stage of the debris campaign will be presented. The combination of these ground-based telescope assets will yield spectral coverage ranging from 0.3 - 25 micrmeters, allowing orbital debris to be studied in depth across a wider wavelength range in the visible and IR than ever previously studied by ODPO. Located on opposite sides of the world and in opposite hemispheres, they offer access to nearly the entire GEO belt on any given night, allowing immediate coverage of nearly any time-critical break-up event. By expanding the methods for surveying, detecting, and characterizing orbital debris, we can better model the debris environment and ultimately gain insight into how to mitigate potential collisions for future missions.

Lederer, S. M.↗
NASA NTRS2019

Design, Testing, and Implementation of the Marshall Grazing Incidence X-ray Spectrometer Slit-Jaw Context Imaging System

The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) is a NASA sounding rocket payload providing a 0.6 – 2.5 nm spectrum with unprecedented spatial and spectral resolution. The instrument is comprised of a novel optical design, featuring a Wolter 1 grazing mirror in the telescope module focusing the solar image on a slit plate; two corrective optics, a diffraction grating and a low-noise detector make up the spectrometer module. When MaGIXS flies on a suborbital launch in 2020, a slit-jaw camera system will image the sun in extreme ultraviolet (EUV) to soft x-ray wavelengths, providing a reference for pointing the telescope and aligning the data to supporting observations from satellites.

Phillip Wilkerson↗
NASA NTRSDate not supplied

In-Situ Process Monitoring, Synchronization, and Mapping Laser Powder Bed Fusion Builds of Ti6Al4V

The use of in-situ process monitoring is of interest to lower the cost of inspection for the qualification of laser powder bed fusion (LPBF) parts. Precise monitoring of the LPBF-AM build process constitutes a multi-scale and multi-discipline task. There are several significant challenges to the in-situ approach: the synchronization of sensor signals to process steps, the physical interpretation and classification of sensor signals, managing very large datasets, and comparing the inputs with the observed monitoring signals. At NASA Langley Research Center, a configurable architecture additive testbed has been developed to monitor the build process with synchronized sensors. The philosophy and method adopted for the synchronization of the cameras with laser power & position Ti-6Al-4V LPBF are described. The synchronized in-situ monitoring signals are compared with ex-situ nondestructive inspection and optical microscopy observations. Such comparisons permit a better understanding of how the sequential process actions of LPBF-AM can affect build quality.

Laser Powder Bed Fusion↗
NASA NTRSDate not supplied

Microgravity Science Glovebox (MSG)

The Microgravity Science Glovebox (MSG) is a research facility located in the Destiny module on the International Space Station (ISS). This facility was designed to accommodate small science and technology experiments in a “workbench” type environment. Because the facility’s working volume is enclosed and held at a negative pressure with respect to the crew living area, the requirements on the experiments for containment of small parts, particulates, fluids, and gasses in the low-gravity Space Station environment are substantially reduced. The concept allows scientific flight hardware to be constructed in close parallel with bench experiments developed in ground-based laboratories. The facility is ideally suited to provide accommodations for exploratory-type investigations that are necessary to gain an initial understanding of the role of gravity in the physics associated with new research areas. Once experiments are transported to the International Space Station the crew installs the experiment hardware in the MSG and configures it for operations. Depending on its design, the actual experiment hardware can be operated either by the crew or by the ground-based investigator through two-way real-time data links. Images can be viewed through the several MSG video cameras, or cameras embedded in the experiment.

containment↗
NASA NTRS1990

Instrumentation in astronomy VII; Proceedings of the Meeting, Tucson, AZ, Feb. 13-17, 1990

The topics discussed include IR detectors and instrumentation, detectors, other instrumentation, optical instrumentation, and space instrumentation. Papers are presented on the IR spectrometer/imager for the ESO VLT, the fiber-coupled high-resolution IR array spectrometer for the Kuiper Airborne Observatory, the Balloon-Borne Infrared Telescope for FIR spectroscopy, and a simple transputer-based CCD camera controller. Attention is given to CCD guidance system for William Herschel Telescope, the New Technology Telescope control/acquisition system as a prototype for the VLT, a control system for spincasting 8-m borosilicate honeycomb mirrors, echelle spectrographs for 8-m class telescopes, and fiber spectroscopy at Palomar Observatory. Other papers are on the Kitt Peak National Observatory fiber actuator device, a two-star photoelectric photometer, an ultrahigh-resolution XUV spectroheliograph, an optical monitor for X-ray satellites, and large-format electrographic and array detectors for a space Schmidt imaging telescope.

Crawford, David L.↗
NASA NTRS2014

Automated Optical Meteor Fluxes and Preliminary Results of Major Showers

NASA's Meteoroid Environment Office (MEO) recently established a two‐station system to calculate daily automated meteor fluxes in the millimeter‐size‐range for both single‐station and double‐station meteors. The cameras each consist of a 17 mm focal length Schneider lens (f/0.95) on a Watec 902H2 Ultimate CCD video camera, producing a 21.7x15.5 degree field of view. This configuration sees meteors down to a magnitude of +6. This paper outlines the concepts of the system, the hardware and software, and results of 3,000+ orbits from the first 18 months of operations. Video from the cameras are run through ASGARD (All Sky and Guided Automatic Real‐time Detection), which performs the meteor detection/photometry, and invokes MILIG and MORB (Borovicka 1990) codes to determine the trajectory, speed, and orbit of the meteor. A subroutine in ASGARD allows for approximate shower identification in single‐station detections. The ASGARD output is used in routines to calculate the flux. Before a flux can be calculated, a weather algorithm indicates if sky conditions are clear enough to calculate fluxes, at which point a limiting magnitude algorithm is employed. The limiting stellar magnitude is found using astrometry.net (Lang et al. 2012) to identify stars and translated to the corresponding shower and sporadic limiting meteor magnitude. It is found every 10 minutes and is able to react to quickly changing sky conditions. The extensive testing of these results on the Geminids and Eta Aquariids is shown. The flux involves dividing the number of meteors by the collecting area of the system, over the time interval for which that collecting area is valid. The flux algorithm employed here differs from others currently in use in that it does not make the gross oversimplication of choosing a single height to calculate the collection area of the system. In the MEO system, the volume is broken up into a set of height intervals, with the collecting areas determined by the position of the active shower or sporadic source radiant. The flux per height interval is calculated and summed to obtain the total meteor flux. Both single station and double station fluxes are currently found daily. Geminid fluxes on the peak night in 2012 (12‐14‐2012) were 0.058 meteors/km2/hr as found with double‐station meteors and 0.057 meteors/ km2/hr as found with single‐station meteors, to a limiting magnitude of +6.5. Both of those numbers are in agreement with the well‐calibrated fluxes from the Canadian Meteor Orbit Radar. Along with flux algorithms and initial flux results, presented will be results from the first 18 months of operation, covering 3,000+ meteoroid orbits.

Blaauw, R.↗
NASA NTRS2016

A Dark Energy Camera Search for Missing Supergiants in the LMC After the Advanced LIGO Gravitational-Wave Event GW150914

The collapse of a stellar core is expected to produce gravitational waves (GWs), neutrinos, and in most cases a luminous supernova. Sometimes, however, the optical event could be significantly less luminous than a supernova and a direct collapse to a black hole, where the star just disappears, is possible. The GW event GW150914 was detected by the LIGO Virgo Collaboration via a burst analysis that gave localization contours enclosing the Large Magellanic Cloud (LMC). Shortly thereafter, we used DECam to observe 102 deg(exp.2) of the localization area,including 38 deg(exp. 2) on the LMC for a missing supergiant search. We construct a complete catalog of LMC luminous red supergiants, the best candidates to undergo invisible core collapse, and collected catalogs of other candidates:less luminous red supergiants, yellow supergiants, blue supergiants, luminous blue variable stars, and Wolf-Rayet stars. Of the objects in the imaging region, all are recovered in the images. The timescale for stellar disappearance is set by the free-fall time, which is a function of the stellar radius. Our observations at 4 and 13 days after the event result in a search sensitive to objects of up to about 200 solar radii. We conclude that it is unlikely that GW150914 was caused by the core collapse of a relatively compact supergiant in the LMC, consistent with the LIGO Collaboration analyses of the gravitational waveform as best interpreted as a high mass binary black hole merger. We discuss how to generalize this search for future very nearby core-collapse candidates.

galaxies: individual (LMC) – gravitational waves↗