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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Thermal Analysis of Next-Generation Space Telescope (NGST) Mirrors During Optical Testing in the X-Ray Calibration Facility (XRCF)

This paper presents Thermal Analysis of the Next Generation Space Telescope (NGST) Mirrors During Optical Testing in the X-Ray Calibration Facility (XRCF). The contents include: 1) NGST Spacecraft Concept; 2) NGST Mirror Development Testing; 3) NGST Development Mirror; 4) Knudsen Number; 5) Free-Molecular Conduction; 6) Accomodation Coefficient; and 7) Results and Recommendations. This paper is presented in viewgraph form.

Page, Tim↗
NASA NTRS1990

Optical testing cryogenic thermal vacuum facility

The construction of a turnkey cryogenic vacuum test facility was recently completed. The facility will be used to measure and record the surface profile of large diameter and 540 kg optics under simulated space conditions. The vacuum test chamber is a vertical stainless steel cylinder with a 3.5 diameter and a 7 m tangent length. The chamber was designed to maximize optical testing quality by minimizing the vibrations between the laser interferometer and the test specimen. This was accomplished by designing the chamber for a high natural frequency and vibration isolating the chamber. An optical test specimen is mounted on a movable presentation stage. During thermal vacuum testing, the specimen may be positioned to + or - 0.00025 cm accuracy with a fine adjustment mechanism. The chamber is evacuated by a close coupled Roots-type blower and rotary vane pump package and two cryopumps. The chamber is equipped with an optically dense gaseous nitrogen cooled thermal shroud. The thermal shroud is used to cool or warm the optical test specimen at a controlled rate. A control system is provided to automatically evacuate the chamber and cooldown the test specimen to the selected control temperature.

Dohogne, Patrick W.↗
NASA NTRS2000

Cryogenic Optical Systems and Instrumentation IX (AM 116) Newly Modified Cryogenic Optical Test Facility at the Marshall Space Flight Center

Marshall Space Flight Center (MSFC) has maintained and operated a world-class x-ray optics and detector testing facility known as the X-ray Calibration Facility (XRCF) since the mid 1970's. The ground test and calibration of the Chandra X-ray Observatory optics and detectors were successfully completed at the XRCF in 1997. The beginning of the Next Generation Space Telescope (NGST) development programs (NMSD, SBMD, AMSD, etc.) and the establishment of the Space Optics Manufacturing Technology Center at MSFC have led to an XRCF modification. In 1999 the facility was upgraded to perform cryogenic testing of lightweight visible optics (without compromising the existing x-ray testing capability). A thermal enclosure capable of 20 degrees Kelvin and vibration isolated instrumentation mount were added. A vacuum-compatible five-axis motion table was modified to operate under cryogenic conditions. Optics up to two meters in diameter with radii of curvature of up to twenty meters can be accommodated. Facility characterization tests and one NGST program mirror test have been completed to date. By July 2000, two other mirrors will be tested. Optical wavefront measurements were made at < 35 degrees Kelvin with several instruments located at the test mirror's radius of curvature. The current wavefront measuring instruments include a Shack-Hartman wavefront sensor, a point diffraction interferometer, a point spread function-measuring device, and a radius of curvature measuring instrument. A vibration insensitive phase shifting interferometer is planned for future optical testing. This paper will present a brief history of the facility, a discussion of its current x-ray optic testing capabilities, and a complete description of the new capabilities in the visible optical testing regime.

Eng, Ronnie↗
NASA NTRS2017

Optical Testing of the James Webb Space Telescope

The James Webb Space Telescope (JWST) will be a large infrared telescope with a 6.5-meter primary mirror, working to an October 2018 launch date. Ground testing for the JWST occurred in two test campaigns, at NASAs Goddard Space Flight Center and Johnson Space Center. The talk describes the JWST and its optical ground testing.

James Webb Space Telescope↗
NASA NTRS2005

Improved Cryogenic Optical Test Capability at Marshall Space Flight Center's X-ray Cryogenic Test Facility

Marshall Space Flight Center's X-ray & Cryogenic Test Facility (XRCF) has been performing optical wavefront testing and thermal structural deformation testing at subliquid nitrogen cryogenic temperatures since 1999. Recent modifications have been made to the facility in support of the James Webb Space Telescope (JWST) program. The test article envelope and the chamber's refrigeration capacity have both been increased. A new larger helium-cooled enclosure has been added to the existing enclosure increasing both the cross-sectional area and the length. This new enclosure is capable of supporting six JWST Primary Mirror Segment Assemblies. A second helium refrigeration system has been installed essentially doubling the cooling capacity available at the facility. Modifications have also been made to the optical instrumentation area. Improved access is now available for both the installation and operation of optical instrumentation outside the vacuum chamber. Chamber configuration, specifications, and performance data will be presented.

Kegley, Jeffrey↗
NASA NTRS2001

MSFC Optical Test Pallet

Several mirror technology development programs have been initiated by Marshall Space Flight Center (MSFC) in support of the Next Generation Space Telescope (NGST) program. The goal is to advance the technology for producing 0.5-2.0 m class, ultra light-weight (<15 kg/sq m) mirrors that can be operated at or near 35 K. The NGST Mirror System Demonstrators (NMSDs) consist of a 1.6 m glass-on-composite mirror from Composite Optics Incorporated (COI) and a 2.0 m glass-on-actuators-on-composite mirror from the University of Arizona. The Subscale Beryllium Mirror Demonstrator (SBMD) is a 0.5 m beryllium mirror from Ball Aerospace. These mirrors require cryogenic surface figure and radius of curvature testing in order to verify their performance in the operational environment predicted for the NGST. An optical testing capability has been developed at the X-Ray Calibration Facility (XRCF) at MSFC. This paper will describe the optical test goals, the optical testing system design, the test instrumentation, and the test system performance as used for SBMD & NMSD cryogenic testing.

Hadaway, James B.↗
NASA NTRS2014

Optical Testing of the James Webb Space Telescope

The James Webb Space Telescope (JWST) will be a large infrared telescope with a 6.5-meter primary mirror, working to a 2018 launch date. Ground testing for the JWST will occur in two test campaigns, at NASAs Goddard Space Flight Center and Johnson Space Center. The talk describes the JWST and its optical ground testing, highlighting the roles of many of the University of Rochester Institute of Optics' alumni as well as current faculty and students.

James Webb Telescope↗
NASA NTRS1991

Characterization of the dimensional stability of advanced metallic materials using an optical test bench structure

The dimensional stability of low-density high specific-strength metal-matrix composites (including 30 vol pct SiC(p)/SXA 24-T6 Al, 25 vol pct SiC(p)/6061-T6 Al, 40 vol pct graphite P100 fiber/6061 Al, 50 vol pct graphite P100 fiber/6061 Al, and 40 vol pct P100 graphite fiber/AZ91D Mg composites) and an Al-Li-Mg metal alloy was evaluated using a specially designed five-strut optical test bench structure. The structure had 30 thermocouple locations, one retroreflector, one linear interferometer multilayer insulation, and various strip heaters. It was placed in a 10 exp -7 torr capability vacuum chamber with a laser head positioned at a window port, and a laser interferometer system for collecting dimensional change data. It was found that composite materials have greater 40-C temporal dimensional stability than the AL-Li-Mg alloy. Aluminum-based composites demonstrated better 40-C temporal stability than Mg-based composites.

Hsieh, Cheng↗
NASA NTRS1989

IRAS colors of carbon stars - An optical spectroscopic test

Optical spectra are obtained of 57 photographic counterparts to IRAS sources not previously studied spectroscopically, and expected on the basis of their IRAS colors to be M or C type stars. Confirmed carbon stars are found only in a restricted range of 12-25 index, and constitute a striking 'vertical' sequence in the 12-25-60 micron color-color diagram. This sequence is in accord with evolutionary models for AGB stars that convert M into C stars by dredge-up, and follow loops in the color-color plane. Optically visible and optically invisible carbon stars occupy different color-color locations consistent with their representations of different evolutionary states in the life of relatively low-mass stars.

Cohen, Martin↗
NASA NTRS1991

Characterization of devices, circuits, and high-temperature superconductor transmission lines by electro-optic testing

The development of a capability for testing transmission lines, devices, and circuits using the optically-based technique of electro-optics sampling was the goal of this project. Electro-optic network analysis of a high-speed device was demonstrated. The project involved research on all of the facets necessary in order to realize this result, including the discovery of the optimum electronic pulse source, development of an adequate test fixture, improvement of the electro-optic probe tip, and identification of a device which responded at high frequency but did not oscillate in the test fixture. In addition, during the process of investigating patterned high-critical-temperature superconductors, several non-contacting techniques for the determination of the transport properties of high T(sub c) films were developed and implemented. These are a transient, optical pump-probe, time-resolved reflectivity experiment, an impulsive-stimulated Raman scattering experiment, and a terahertz-beam coherent-spectroscopy experiment. The latter technique has enabled us to measure both the complex refractive index of an MgO substrate used for high-T(sub c) films and the complex conductivity of a YBa2Cu3O(7-x) sample. This information was acquired across an extremely wide frequency range: from the microwave to the submillimeter-wave regime. The experiments on the YBCO were conducted without patterning of, or contact to, the thin film. Thus, the need for the more difficult transmission-line experiments was eliminated. Progress in all of these areas was made and is documented in a number of papers. These papers may be found in the section listing the abstracts of the publications that were issued during the course of the research.

Whitaker, John F.↗
NASA NTRS1980

Pressure and temperature fields associated with aero-optics tests

The experimental investigation carried out in a 6 x 6 ft wind tunnel on four model configurations in the aero-optics series of tests are described. The data obtained on the random pressures (static and total pressures) and total temperatures are presented. In addition, the data for static pressure fluctuations on the Coelostat turret model are presented. The measurements indicate that the random pressures and temperature are negligible compared to their own mean (or steady state) values for the four models considered, thus allowing considerable simplification in the calculations to obtain the statistical properties of the density field. In the case of the Coelostat model tests these simplifications cannot be assumed a priori and require further investigation.

Raman, K. R.↗
NASA NTRS1994

Large area soft x-ray collimator to facilitate x-ray optics testing

The first objective of this program is to design a nested conical foil x-ray optic which will collimate x-rays diverging from a point source. The collimator could then be employed in a small, inexpensive x-ray test stand which would be used to test various x-ray optics and detector systems. The second objective is to demonstrate the fabrication of the x-ray reflectors for this optic using lacquer-smoothing and zero-stress electroforming techniques.

Espy, Samuel L.↗
NASA NTRS1995

A ruggedness evaluation of procedures for damage threshold testing optical materials

A ruggedness evaluation of approaches to damage threshold testing was performed to determine the influence of three procedural variables on damage threshold data. The differences between the number of test sites evaluated at an applied fluence level (1 site versus 10 sites), the number of laser pulses at each test site (1 pulse versus 200 pulses), and the beam diameter (0.35 mm versus 0.70 mm) were all found to significantly influence the damage threshold data over a 99-percent confidence interval.

Hooker, Matthew W.↗
NASA NTRS2008

Development and Optical Testing of the Camera, Hand Lens, and Microscope Probe with Scannable Laser Spectroscopy (CHAMP-SLS)

Conducting high resolution field microscopy with coupled laser spectroscopy that can be used to selectively analyze the surface chemistry of individual pixels in a scene is an enabling capability for next generation robotic and manned spaceflight missions, civil, and military applications. In the laboratory, we use a range of imaging and surface preparation tools that provide us with in-focus images, context imaging for identifying features that we want to investigate at high magnification, and surface-optical coupling that allows us to apply optical spectroscopic analysis techniques for analyzing surface chemistry particularly at high magnifications. The camera, hand lens, and microscope probe with scannable laser spectroscopy (CHAMP-SLS) is an imaging/spectroscopy instrument capable of imaging continuously from infinity down to high resolution microscopy (resolution of approx. 1 micron/pixel in a final camera format), the closer CHAMP-SLS is placed to a feature, the higher the resultant magnification. At hand lens to microscopic magnifications, the imaged scene can be selectively interrogated with point spectroscopic techniques such as Raman spectroscopy, microscopic Laser Induced Breakdown Spectroscopy (micro-LIBS), laser ablation mass-spectrometry, Fluorescence spectroscopy, and/or Reflectance spectroscopy. This paper summarizes the optical design, development, and testing of the CHAMP-SLS optics.

Fluorescence↗
NASA NTRS2017

Optical Testing Using Portable Laser Coordinate Measuring Instruments

High precision, portable coordinate measuring instruments (CMI) such as laser radars (LR) and laser trackers (LT) have been used for optical system alignment and integration. The LRs ability to perform a non-contact scan of surfaces was previously utilized to characterize large spherical and aspheric mirrors. In this paper, we explore the use of a CMI as an accurate, fast, robust, and non-contact tool for prescription characterization of powered optical surfaces. Using Nikons MV-224350 LR and Leicas Absolute Tracker AT401402 instruments, proof of concept measurements were performed to characterize a variety of optical components by measuring the actual and apparent, or equivalently the direct and through (DT), coordinates of calibrated metrology targets. Custom macros in metrology software and other data reduction code were developed to compute surface-ray intercepts and surface slopes from the DT shots. The calculated data is fit to an aspheric surface formula to obtain the optimum prescription. The results were compared to the nominal parameters and were crosschecked using LR scans or other approaches. We discuss potential applications across the fields of optical component fabrication and system alignment and testing.

Khreishi, M.↗
NASA NTRS2017

Optical Testing Using Portable Laser Coordinate Measuring Instruments

High precision, portable coordinate measuring instruments (CMI) such as laser radars (LR) and laser trackers (LT) have been used for optical system alignment and integration. The LR's ability to perform a non-contact scan of surfaces was previously utilized to characterize large spherical and aspheric mirrors. In this paper, we explore the use of a CMI as an accurate, fast, robust, and non-contact tool for prescription characterization of powered optical surfaces. Using Nikon's MV-224/350 LR and Leica's Absolute Tracker AT401/402 instruments, proof of concept measurements were performed to characterize a variety of optical components by measuring the actual and apparent, or equivalently the "direct and through" (D&T), coordinates of calibrated metrology targets. Custom macros in metrology software and other data reduction code were developed to compute surface-ray intercepts and surface slopes from the D&T shots. The calculated data is fit to an aspheric surface formula to obtain the optimum prescription. The results were compared to the nominal parameters and were crosschecked using LR scans or other approaches. We discuss potential applications across the fields of optical component fabrication and system alignment and testing.

Khreishi, Manal↗
NASA NTRS1993

Interferometric and optical tests of water window imaging x ray microscopes

Interferometric tests of Schwarzchild X-ray Microscope are performed to evaluate the optical properties and alignment of the components. Photographic measurements of the spatial resolution, focal properties, and vignetting characteristics of the prototype Water Window Imaging X-ray Microscope are made and analyzed.

Johnson, R. Barry↗