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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 1,459 records · Page 81
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Field measurement of reflectance - Some major considerations

The simultaneous use of two portable spectroradiometers to measure radiance and irradiance from crop fields is reported. Two sensors were employed to assess the crop cover radiance reflectance, while a third instrument measured irradiance from a white Lambertian reflectance target, with all radiometers being equipped with optic fiber probes. Calibration procedures for the instruments are outlined, including the usage of laboratory standards and recalibration before every test by exposing all sensors to the Lambertian reflector. Calculation of the angular geometry between the sun, target, and sensor was found to be necessary to determine the angle dependence for each wave band and the surface variability. It is recommended that suitable portable equipment be fabricated with calibration procedures and manuals that can be used by the nonelectrical engineer in order to standardize measurements for comparison between two instruments.

Duggin, M. J.↗
NASA NTRS2008

Recent Developments in the Alignment and Test Plans for the James Webb Space Telescope Integrated Science Instrument Module

The James Webb Space Telescope (JWST) is a 6.6m diameter, segmented, deployable telescope for cryogenic IR space astronomy (approximately 40K). The JWST Observatory architecture includes the Optical Telescope Element (OTE) and the Integrated Science Instrument Module (ISIM) element that contains four science instruments (SI) including a Guider. The SIs and Guider are mounted to a composite metering structure with outer dimensions of 2.1 x 2.2 x 1.9m. The SI and Guider units are integrated to the ISIM structure and optically tested at NASA/Goddard Space Flight Center as an instrument suite using an OTE SIMulator (OSIM). OSIM is a high-fidelity, cryogenic JWST telescope simulator that features a approximately 1.5m diameter powered mirror. The SIs are aligned to the structure's coordinate system under ambient, clean room conditions using laser tracker and theodolite metrology. Temperature-induced mechanical SI alignment and structural changes are measured using a photogrammetric measurement system at ambient and cryogenic temperatures. OSIM is aligned to the ISIM mechanical coordinate system at the cryogenic operating temperature via internal mechanisms and feedback from alignment sensors in six degrees of freedom. SI performance, including focus, pupil shear and wavefront error, is evaluated at the operating temperature using OSIM. We present an updated plan for the assembly and ambient and cryogenic optical alignment, test and verification of the ISIM element.

Ohl, Raymond↗
NASA NTRS2014

Obtaining Remote-Sensing Reflectance from Multiple Instrument Systems

Obtaining accurate in situ measurements of Apparent Optical Properties (AOPs) is critical to maintaining satellite data quality. One approach to ensure accuracy is to deploy several independent instruments to measure the same phenomenon. During a cruise in June 2012, off the lee coast of the island of Hawaii, repeated profiles were made with two separate radiometric systems, one from Satlantic, Inc. (Hyperpro) and the other from Biospherical Instruments, Inc. (C-Ops). The C-Ops is multispectral, while the Hyperpro is hyperspectral. Both measure above-water solar irradiance (E(sub s)), downwelling in-water irradiance (E(sub d)), and upwelling in-water radiance (L(sub u)). From these measurements remotely-sensed reflectance (R(sub rs))can be calculated and compared with satellite data. All instruments were calibrated shortly before use, and while differences are to be expected due to temporal changes and spectral weighting differences, these should be consistent and minimal. We explore these differences, and compare to data retrieved from the NASA Moderate Resolution Imaging Spectroradiometer onboard Aqua (MODIS Aqua) when available. We also examine data collection and processing protocols for these systems.

Carbon↗
DOE OSTI2025

Fast quantum interferometry at the nanometer and attosecond scales with energy-entangled photons

In classical optical interferometry, loss and background complicate achieving fast nanometer-resolution measurements with illumination at low light levels. Conversely, quantum two-photon interference is unaffected by loss and background, but nanometer-scale resolution is physically difficult to realize. As a solution, we enhance two-photon interference with highly nondegenerate energy entanglement featuring photon frequencies separated by 177 THz. We observe measurement resolution at the nanometer (attosecond) scale with only O(10 4 ) photon pairs, despite the presence of background and loss. Our nondestructive thickness measurement of a metallic thin film agrees with atomic force microscopy, which often achieves better resolution via destructive means. With contactless, nondestructive measurements in seconds or faster, our instrument enables metrological studies in optically challenging contexts where background, loss, or photosensitivity are factors.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1984

The role of scientists in developing Hubble Space Telescope

The objective of the Hubble Space Telescope Program is to build and operate a high-performance, fully-instrumented and long-lived optical observatory in earth orbit. Key Program elements are (1) a logistic strategy of Shuttle launch/maintenance and TDRSS communications, (2) overall responsibility at the MSFC Project for developing both the flight and ground systems, and (3) scientific participation in ST development and responsibility after launch for conducting the observing program. The ST Project is a management structure with a budget and schedule for delivering an ST system capable of achieving its established scientific objectives. The Project distributes through contracts the responsibility for supplying particular components, but retains the responsibility for system-level integrity. Scientists have set the performance objectives and now support the Project during the development stage by providing (1) PI management of the five Science Instruments, (2) continuing translations of scientific requirements into engineering specifications, (3) oversight of designs and performance tests, and (4) specific expertise on technical concerns.

Brown, R. A.↗
DOE OSTI2022

Femtosecond-Terawatt Hard X-Ray Pulse Generation with Chirped Pulse Amplification on a Free Electron Laser

Advances of high intensity lasers have opened up the field of strong field physics and led to a broad range of technological applications. Recent x ray laser sources and optics development makes it possible to obtain extremely high intensity and brightness at x ray wavelengths. In this paper, we present a system design that implements chirped pulse amplification for hard x ray free electron lasers. Numerical modeling with realistic experimental parameters show that near-transform-limit single-femtosecond hard x ray laser pulses with peak power exceeding 1 TW and brightness exceeding 4×10 35 s -1 mm -2 mrad -2 0.1\%bandwdith -1 can be consistently generated. In conclusion, realization of such beam qualities is essential for establishing systematic and quantitative understanding of strong field x-ray physics and nonlinear x ray optics phenomena.

47 OTHER INSTRUMENTATION↗
NASA NTRS1980

Quantitative optical scanning tests of complex microcircuits

An approach for the development of the optical scanner as a screening inspection instrument for microcircuits involves comparing the quantitative differences in photoresponse images and then correlating them with electrical parameter differences in test devices. The existing optical scanner was modified so that the photoresponse data could be recorded and subsequently digitized. A method was devised for applying digital image processing techniques to the digitized photoresponse data in order to quantitatively compare the data. Electrical tests were performed and photoresponse images were recorded before and following life test intervals on two groups of test devices. Correlations were made between differences or changes in the electrical parameters of the test devices.

Erickson, J. J.↗
NASA NTRS2010

Advances in Measuring the Apparent Optical Properties (AOPs) of Optically Complex Waters

This report documents new technology used to measure the apparent optical properties (AOPs) of optically complex waters. The principal objective is to be prepared for the launch of next-generation ocean color satellites with the most capable commercial off-the-shelf (COTS) instrumentation. An enhanced COTS radiometer was the starting point for designing and testing the new sensors. The follow-on steps were to apply the lessons learned towards a new in-water profiler based on a kite-shaped backplane for mounting the light sensors. The next level of sophistication involved evaluating new radiometers emerging from a development activity based on so-called microradiometers. The exploitation of microradiometers resulted in an in-water profiling system, which includes a sensor networking capability to control ancillary sensors like a shadowband or global positioning system (GPS) device. A principal advantage of microradiometers is their flexibility in producing, interconnecting, and maintaining instruments. The full problem set for collecting sea-truth data--whether in coastal waters or the open ocean-- involves other aspects of data collection that were improved for instruments measuring both AOPs and inherent optical properties (IOPs), if the uncertainty budget is to be minimized. New capabilities associated with deploying solar references were developed as well as a compact solution for recovering in-water instrument systems from small boats.

Morrow, John H.↗
DOE OSTI2020

Monolithic Spatial Heterodyne Raman Spectrometers (mSHRS): Toward highly miniature chemical sensors for deployment on moving platforms (Final Report, Phase I)

This report covers phase 1 (year 1) of the mSHRS project. Our ultimate long-term goal is to develop highly miniature Raman analyzers, known as spatial heterodyne Raman spectrometers (SHRS), that are deployable as in-situ chemical sensors on moving platforms. During Phase I (FY19/20) funding, our team focused our efforts solely on the key innovation needed toward realizing that goal: the development of the monolithic interferometer comprising the beam splitter and gratings with the appropriate design parameters and tolerances to enable Raman interferometry. We successfully developed and characterized the performance of the first monolithic SHRS devices including a monolithic version that incorporates field-widened optics. Our solid-state design approach integrated all optical components as a single monolithic unit for maintaining precise optical alignment during sensor operation, a requirement for operating in a vibration prone environment. This project has two principle activities: (1) Design and fabricate monolithic SHRS devices (i.e. monolithic device task) and (2) characterize the mSHRS devices in terms of performance (i.e. the Monolithic SHRS characterization task).

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1995

Test of the magneto optical filter during the comet P/Shoemaker-Levy 9 impacts on Jupiter. A Doppler signal detected?

The observations made in July 1994 on the impact of fragment A of the comet P/Shoemaker-Levy 9 with Jupiter are described. The instrumentation used was a magneto-optical filter, acting as a two-channel filter. The data showed a double-peak transient which occurred after the impact, and whose general properties indicated a true jovian origin. The peaks appear in absorption. A numerical simulation can explain the main characteristics of the observed signal where the two peaks have the same polarity and appear only in the channel at shorter wavelengths. The simulation carried out appeared to indicate that the observed signal could be produced by the combination of shock waves and the expanding material with a velocity of 13 +/- 8 km/s. This implies that two separate impacts may have been observed. The developed simulation can be extended to predict long term effects.

Cacciani, A.↗
NASA NTRS1984

Optical-system design for next-generation pushbroom sensors

Next-generation pushbroom sensors for earth observation require high-performance optics that provide high spatial resolution over wide fields of view. Specifically, blur diameters on the order of 10 to 15 microns are needed over 5 to 15 deg fields. In addition to this fundamental level of optical performance, other characteristics, such as spatial coregistration of spectral bands, flat focal plane, telecentricity, and workable pupil location are significant instrument design considerations. The detector-assembly design, optical line-of-sight pointing method and sensor packaging all hinge on these secondary attributes. Moreover, the need for broad spectral coverage, ranging from 0.4 to 12.5 microns, places an additional constraint on optical design. This paper presents alternative design forms that are candidates for wide-field pushbroom sensors, and discusses the instrument-design tradeoffs that are linked to the selection of these alternate optical approaches.

Mika, A. M.↗
NASA NTRS2016

Cryogenic Fiber Optic Assemblies for Spaceflight Environments: Design, Manufacturing, Testing, and Integration

Fiber optic assemblies have been used on spaceflight missions for many years as an enabling technology for routing, transmitting, and detecting optical signals. Due to the overwhelming success of NASA in implementing fiber optic assemblies on spaceflight science-based instruments, system scientists increasingly request fibers that perform in extreme environments while still maintaining very high optical transmission, stability, and reliability. Many new applications require fiber optic assemblies that will operate down to cryogenic temperatures as low as 20 Kelvin. In order for the fiber assemblies to operate with little loss in optical throughput at these extreme temperatures requires a system level approach all the way from how the fiber assembly is manufactured to how it is held, routed, and integrated. The NASA Goddard Code 562 Photonics Group has been designing, manufacturing, testing, and integrating fiber optics for spaceflight and other high reliability applications for nearly 20 years. Design techniques and lessons learned over the years are consistently applied to developing new fiber optic assemblies that meet these demanding environments. System level trades, fiber assembly design methods, manufacturing, testing, and integration will be discussed. Specific recent examples of ground support equipment for the James Webb Space Telescope (JWST); the Ice, Cloud and Land Elevation Satellite-2 (ICESat-2); and others will be included.

Fiber Optic↗
NASA NTRS2014

A New Differential Absorption Lidar to Measure Sub-Hourly Fluctuation of Tropospheric Ozone Profiles in the Baltimore - Washington D.C. Region

Tropospheric ozone profiles have been retrieved from the new ground based National Aeronautics and Space Administration (NASA) Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) in Greenbelt, MD (38.99 N, 76.84 W, 57 meters ASL) from 400 m to 12 km AGL. Current atmospheric satellite instruments cannot peer through the optically thick stratospheric ozone layer to remotely sense boundary layer tropospheric ozone. In order to monitor this lower ozone more effectively, the Tropospheric Ozone Lidar Network (TOLNet) has been developed, which currently consists of five stations across the US. The GSFC TROPOZ DIAL is based on the Differential Absorption Lidar (DIAL) technique, which currently detects two wavelengths, 289 and 299 nm. Ozone is absorbed more strongly at 289 nm than at 299 nm. The DIAL technique exploits this difference between the returned backscatter signals to obtain the ozone number density as a function of altitude. The transmitted wavelengths are generated by focusing the output of a quadrupled Nd:YAG laser beam (266 nm) into a pair of Raman cells, filled with high pressure hydrogen and deuterium. Stimulated Raman Scattering (SRS) within the focus generates a significant fraction of the pump energy at the first Stokes shift. With the knowledge of the ozone absorption coefficient at these two wavelengths, the range resolved number density can be derived. An interesting atmospheric case study involving the Stratospheric-Tropospheric Exchange (STE) of ozone is shown to emphasize the regional importance of this instrument as well as assessing the validation and calibration of data. The retrieval yields an uncertainty of 16-19 percent from 0-1.5 km, 10-18 percent from 1.5-3 km, and 11-25 percent from 3 km to 12 km. There are currently surface ozone measurements hourly and ozonesonde launches occasionally, but this system will be the first to make routine tropospheric ozone profile measurements in the Baltimore-Washington DC area.

Stimulated Raman Scattering↗
NASA NTRS1987

SAFIRE - A novel high resolution cooled spectrometer for atmospheric research

The SAFIRE (Spectroscopy of Atmospheric Far Infra-Red Emissions) experiment is discussed with particular reference to the scientific aims and the conceptual instrument design of the project. The principal requirements of the experiment are reviewed, and it is shown how these requirements are met in the instrument concept. In particular, measurements of hydrogen oxides and other important species in the stratosphere require a far infrared limb sounder. Some problems involved in the optical and thermal design of the instrument are examined.

Harries, J. E.↗
DOE OSTI2022

Binary pseudo-random array standards for calibration of 3D optical surface profilers used for metrology with aspheric x-ray optics

High-accuracy surface metrology is vitally important in manufacturing ultra-high-quality free-form mirrors designed to manipulate x-ray light with nanometer-scale wavelengths. The current and potential capabilities of x˗ray mirror manufacturing are limited by inherent imperfections of the integrated metrology tools. Metrology tools are currently calibrated with super-polished flat test-standard/reference mirrors. This is acceptable for fabrication of slightly curved x-ray optics. However, for even moderately curved aspherical x-ray mirrors the flat-reference calibration is not sufficiently accurate. For micro-stitching interferometry developed for surface measurements with curved x-ray mirrors, the tool aberration errors are known to be transferred into the optical surface topography of x-ray mirrors. Our approach to improving metrology is to thoroughly calibrate the measuring tool and apply the results of the calibration to deconvolution of the measured data. Here we explore the application of a recently developed technique for calibrating the instrument transfer function (ITF) of 3D optical surface profilers to metrology with significantly curved x-ray optics. The technique, based on test standards patterned with two-dimensional (2D) binary pseudo-random arrays (BPRAs), employs the unique properties of the BPRA patterns in the spatial frequency domain. The inherent 2D power spectral density of the pattern has a deterministic white-noise-like character that allows direct determination of the ITF with uniform sensitivity over the entire spatial frequency range and field of view of an instrument. The high efficacy of the technique has been previously demonstrated in application to metrology with flat and slightly curved optics. Here, we concentrate on development of an efficient fabrication process for production of highly randomized (HR) BPRA test standards on flat and 500-mm spherical optical substrates. We also compare and discuss the results of the ITF calibration of an interferometric microscope when using the HR BPRA standards on flat and curved substrates.

Munechika, Keiko↗
NASA NTRS1983

Near-infrared mapping spectrometer optical subsystem development and testing

The Near-Infrared Mapping Spectrometer (NIMS) is one of the four remote-sensing science instruments of the Galileo Orbiter scientific payload. The NIMS scientific objectives require operating the detector and optical subsystem at cryogenic temperatures. The necessity of assembling, aligning, and testing the optics at room temperature and meeting design specifications at the cryogenic operating temperature (130 K) presented a set of challenging technical problems. A systematic approach to the development of athermalized mounts and supporting structures for optical components is described. A technique utilizing the visible spectral range and supplementary ray-trace information for alignment of an infrared instrument is presented. The optical subsystem point-spread function and spatial and spectral resolution were determined at room temperature using selected spectral and spatial targets. Based on thermal-distortion analyses of the structure and mounts, compensators were selected, implemented, and verified at cryogenic temperatures. The selection of the compensator and the overall system performance were verified in a thermal vacuum chamber. Various external and internal calibration targets were used.

Macenka, S. A.↗
DOE OSTI2020

A multi-terawatt two-color beam for high-power field-controlled nonlinear optics

Two-color laser beams are instrumental in light-field control and enhancement of high-order harmonic, spectral supercontinuum, and terahertz radiation generated in gases, plasmas, and solids. Here we demonstrate a multi-terawatt two-color beam produced using a relativistic plasma mirror, with 110 mJ at 800 nm and 30 mJ at 400 nm. Both color components have high spatial quality and can be simultaneously focused, provided that the plasma mirror lies within a Rayleigh range of the driving fundamental beam. Favorable scaling of second-harmonic generation by plasma mirrors at relativistic intensities suggests them as an excellent tool for multi-color waveform synthesis beyond the petawatt level.

42 ENGINEERING↗