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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Micro-Spectrometer for Resource Mapping in Extreme Environments

Measurements and analyses of resources within permanently shadowed craters and along steep embankments on extraterrestrial surfaces pose extreme challenges since astronauts and rovers cannot access them. However, these areas offer the potential for the greatest scientific returns. Researchers at the NASA Langley Research Center (LaRC) invented a deployable wireless micro-spectrometer that can access those challenging areas and deliver telemetry data to a receiver safely outside those extreme environments. The micro-spectrometers are designed for deployment by an astronaut, a rover, or a lander flying overhead. This device can also be installed on rover tires, under the astronaut’s shoes, or on a cane stick. The bullet-like, expendable micro-spectrometer can penetrate into soil to spectrally identify the components of soil, such as water, He-3, or other minerals. The signals from the soil assay data are transmitted to a mother station through a telemetry system. This LaRC developed micro-spectrometer bullet consists of micro-spectrometer optics with an all-imbedded, burst-mode, light-emitting-diode ultraviolet (LED UV) light source, a super-capacitor with control electronics, and telemetry electronics. Prototypes have been fabricated to demonstrate a spectral assay of soil components. Further maturation of this technology would be necessary for demonstrations on the Moon.

micro-spectrometer↗
DOE OSTI2022

Broadband Wide-Angle VElocity Selector (BWAVES) neutron spectrometer designed for the SNS Second Target Station

A recently proposed wide-angle velocity selector (WAVES) device for choosing the velocity of detected neutrons after they have been scattered by the sample paves the way for inverted geometry neutron spectrometers with continuously adjustable final neutron wavelength. BWAVES broadband inverted geometry spectrometer proposed for the Second Target Station at the Spallation Neutron Source at Oak Ridge National Laboratory is designed using WAVES to simultaneously probe dynamic processes spanning 4.5 decades in time (energy transfer). This makes BWAVES a uniquely flexible instrument which can be viewed as either a quasielasitc neutron scattering (QENS) spectrometer with a practically unlimited (overlapping with the vibrational excitations) range of energy transfers, or a broadband inelastic vibrational neutron spectrometer with QENS capabilities, including a range of accessible momentum transfer (Q) and a sufficiently high energy resolution at the elastic line. The new capabilities offered by BWAVES will expand the application of neutron scattering in ways not possible with existing neutron spectrometers.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Spectral characterization and performance of SPT-SLIM on-chip filterbank spectrometers

The South Pole Telescope Shirokoff Line Intensity Mapper (SPT-SLIM) experiment is a pathfinder for demonstrating the use of on-chip spectrometers for millimeter (mm) Line Intensity Mapping (LIM). We present spectral bandpass measurements of the SPT-SLIM spectrometer channels made on site using a Fourier Transform Spectrometer during the first deployment of SPT-SLIM in the 2024-2025 Austral summer season. We note the effect of FTS systematics on measurements of on-chip filterbank spectrometer resolutions and demonstrate a technique for measuring the narrow band passes of the SPT-SLIM filterbanks that improves beyond the intrinsic resolution of a Fourier Transform Spectrometer.

Benson, C. S. [Cardiff U.]↗
DOE OSTI2022

Heterodyne spectrometer sensitivity limit for quantum networking

We report optical heterodyne detection-based spectrometers are attractive due to their relatively simple construction and ultrahigh resolution. Here we demonstrate a proof-of-principle single-mode optical-fiber-based heterodyne spectrometer that has picometer resolution and quantum-limited sensitivity around 1550 nm. Moreover, we report a generalized quantum limit of detecting broadband multispectral-temporal-mode light using heterodyne detection, which provides a sensitivity limit on a heterodyne detection-based optical spectrometer. We then compare this sensitivity limit to several spectrometer types and dim light sources of interest such as spontaneous parametric downconversion, Raman scattering, and spontaneous four-wave mixing. We calculate that the heterodyne spectrometer is significantly less sensitive than a single-photon detector and is unable to detect these dim light sources, except for the brightest and narrowest-bandwidth examples.

47 OTHER INSTRUMENTATION↗
DOE OSTI2023

Compact single-shot soft X-ray photon spectrometer for free-electron laser diagnostics

The photon spectrum from free-electron laser (FEL) light sources offers valuable information in time-resolved experiments and machine optimization in the spectral and temporal domains. We have developed a compact single-shot photon spectrometer to diagnose soft X-ray spectra. The spectrometer consists of an array of off-axis Fresnel zone plates (FZP) that act as transmission-imaging gratings, a Ce:YAG scintillator, and a microscope objective to image the scintillation target onto a two-dimensional imaging detector. This spectrometer operates in segmented energy ranges which covers tens of electronvolts for each absorption edge associated with several atomic constituents: carbon, nitrogen, oxygen, and neon. The spectrometer’s performance is demonstrated at a repetition rate of 120 Hz, but our detection scheme can be easily extended to 200 kHz spectral collection by employing a fast complementary metal oxide semiconductor (CMOS) line-scan camera to detect the light from the scintillator. This compact photon spectrometer provides an opportunity for monitoring the spectrum downstream of an endstation in a limited space environment with sub-electronvolt energy resolution.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1971

Lunar orbital mass spectrometer experiment

The design, development, manufacture, test and calibration of five lunar orbital mass spectrometers with the four associated ground support equipment test sets are discussed. A mass spectrometer was installed in the Apollo 15 and one in the Apollo 16 Scientific Instrument Module within the Service Module. The Apollo 15 mass spectrometer was operated with collection of 38 hours of mass spectra data during lunar orbit and 50 hours of data were collected during transearth coast. The Apollo 16 mass spectrometer was operated with collection of 76 hours of mass spectra data during lunar orbit. However, the Apollo 16 mass spectrometer was ejected into lunar orbit upon malfunction of spacecraft boom system just prior to transearth insection and no transearth coast data was possible.

Lord, W. P.↗
NASA NTRS1974

Data processing improvements for the Skylab S-191 EREP spectrometer

The characteristics of the S-191 spectrometer (filter wheel infrared spectrometer) are discussed. Inherent deficiencies in previous spectrometers are described and the techniques for correcting the deficiencies are explained. The radiance errors caused by error in wavelength are identified and the effects on the accuracy of the spectrometer are described. It is stated that the most important source of error in the S-191 spectrometer is off-band radiation in which the detected radiation is far from the wavelength which is expected to be detected by the sensor at that particular time. A numerical analysis of the effects of off-band radiation is developed.

Campbell, C. E.↗
NASA NTRS1979

Study and evaluation of impulse mass spectrometers for ion analysis in the D and E regions of the ionosphere

Theoretical and numerical analyses were made of planar, cylindrical and spherical electrode time-of-flight mass spectrometers in order to optimize their operating conditions. A numerical analysis of potential barrier gating in time-of-flight spectrometers was also made. The results were used in the design of several small mass spectrometers. These were constructed and tested in a laboratory space simulator. Detailed experimental studies of a miniature cylindrical electrode time of flight mass spectrometer and of a miniature hemispherical electrode time of flight mass spectrometer were made. The extremely high sensitivity of these instruments and their ability to operate at D region pressures with an open source make them ideal instruments for D region ion composition measurements.

Kendall, B. R.↗
NASA NTRS1983

Reflecting Schmidt imaging spectrometers

A new wide-angle imaging spectrometer configuration is proposed where an all-reflecting Schmidt camera is used with a prism spectrometer to give a field of view up to 60 deg or more. Four different designs using this approach are presented. These are the Imaging Spectrometer Free Flyer, the Shuttle Imaging Spectrometer A, the Shuttle Imaging Spectrometer B, and the Wide-Field System. These systems are capable of broadband spectral coverage from 0.4 to 2.5 microns, with footprints 20 m on a side or less, and with swath widths hundreds of kilometers; they are capable of spectral resolving powers of 200 or more.

Breckinridge, J. B.↗
NASA NTRS1982

Use of a Fourier transform spectrometer on a balloon-borne telescope and at the multiple mirror telescope (MMT)

The design and use of an infrared Fourier transform spectrometer which has been used for observations of laboratory, stratospheric, and astronomical spectra are described. The spectrometer has a spectral resolution of 0.032/cm and has operated in the mid-infrared (12 to 13 microns) as well as the far-infrared (40 to 140 microns), using both bolometer and photoconductor cryogenic detectors. The spectrometer is optically sized to accept an f/9 beam from the multi-mirror telescope (MMT). The optical and electronic design are discussed, including remote operation of the spectrometer on a balloon-borne 102-cm telescope. The performance of the laser-controlled, screw-driven moving cat's-eye mirror is discussed. Segments of typical far-infrared balloon flight spectra, lab spectra, and mid-infrared MMT spectra are presented. Data reduction, interferogram processing, artifact removal, wavelength calibration, and intensity calibration methods are discussed. Future use of the spectrometer is outlined.

Traub, W. A.↗
NASA NTRS1986

Imaging spectrometers for remote sensing from space

Three imaging spectrometers and two camera systems for remote sensing are described. Two of the imaging spectrometers are versions of the Visible and Infrared Mapping Spectrometer (VIMS) for Mars Observer and the Comet Rendezvous Asteroid Flyby (CRAF) mission. The other spectrometer is the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) which is currently under construction. The optical imaging systems are the wide angle and narrow angle cameras for the CRAF mission.

Chrisp, M. P.↗
NASA NTRS1988

Evaluation of Airborne Visible/Infrared Imaging Spectrometer Data of the Mountain Pass, California carbonatite complex

Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data of the Mountain Pass, California carbonatite complex were examined to evaluate the AVIRIS instrument performance and to explore alternative methods of data calibration. Although signal-to-noise estimates derived from the data indicated that the A, B, and C spectrometers generally met the original instrument design objectives, the S/N performance of the D spectrometer was below expectations. Signal-to-noise values of 20 to 1 or lower were typical of the D spectrometer and several detectors in the D spectrometer array were shown to have poor electronic stability. The AVIRIS data also exhibited periodic noise, and were occasionally subject to abrupt dark current offsets. Despite these limitations, a number of mineral absorption bands, including CO3, Al-OH, and unusual rare earth element bands, were observed for mine areas near the main carbonatite body. To discern these bands, two different calibration procedures were applied to remove atmospheric and solar components from the remote sensing data. The two procedures, referred to as the single spectrum and the flat field calibration methods gave distinctly different results. In principle, the single spectrum method should be more accurate; however, additional fieldwork is needed to rigorously determine the degree of calibration success.

Crowley, James↗
NASA NTRS1988

Airborne Visible/Infrared Imaging Spectrometer (AVIRIS)

The development of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) has been completed at JPL. This paper outlines the functional requirements of the spectrometer optics subsystem, and describes the spectrometer optical design. The optical subsystem performance is shown in terms of spectral modulation transfer functions, radial energy distributions, and system transmission at selected wavelengths for the four spectrometers. An outline of the spectrometer alignment is included.

Macenka, Steven A.↗
NASA NTRS1988

Earth Observing System - A platform for imaging spectrometers

Several advanced imaging spectrometers will be deployed on the Space Station Polar Platforms as a part of the Earth Observing System (EOS) program. Two of these, the Moderate-Resolution Imaging Spectrometer (MODIS) and High-Resolution Imaging Spectrometer (HIRIS), will be provided as facility instruments, and currently are under conceptual study at the Jet Propulsion Laboratory and the Goddard Space Flight Center. Other imaging spectrometer concepts, including proposals for a thermal infrared imaging spectrometer, are expected in response to the EOS Announcement of Opportunity scheduled for release in January of 1988.

Vane, Deborah↗
NASA NTRS1989

Hot oxygen geocorona as inferred from neutral exospheric models and mass spectrometer measurements

Summer hot oxygen densities of 10,000-30,000 per cubic cm at 1100 km (or 100,000-300,000 at 550 km) for low to moderate solar activities are inferred from differences between satellite drag and mass-spectrometer-based models. At high solar activities, densities at 925 km from 100,000-400,000 (or 5 x 10 to the 5th to 2 x 10 to the 6th at 550 km) are inferred from a limited number of Dynamics Explorer mass spectrometer measurements. The densities are of the same order as those reported previously from ground-based optical measurements. It is pointed out that a detailed theoretical calculation of the hot oxygen distribution consistent with the cool populations in mass-spectrometer-based models would provide the basis for a more complete interpretation of mass spectrometer data and of high-altitude differences between drag-based and mass-spectrometer-based models. It is concluded that hot oxygen could be providing the major contribution to satellite drag in the summer lower exosphere during low solar activity.

Hedin, A. E.↗
NASA NTRS1990

A multi-aperture spectrometer design for the Atmospheric Infrared Sounder (AIRS)

The baseline multiaperture echelle spectrometer for the Atmospheric IR Sounder (AIRS) is described in terms of design and applications. The functional requirements for the optical design are set forth including the 1-K measurement goal, the 3.4-15.4 spectral bandpass, and the full global coverage twice daily. The multiaperture spectrometer is compared to the cross-dispersed spectrometer, and the multiaperture model is found to permit specific adjustments to the signal-to-noise ratio. The optical design of the spectrometer is described in terms of the focal-plane constraints, the multiaperture pupil-imaging relay, the spectrometer collimator, and the grating format and efficiency. The multiaperture design is found to have a good spectral-response function, and a 1.2 percent signal change is noted for a 95-percent unpolarized scene. The AIRS instrument is illustrated in its deployment configuration and is concluded to be capable of fulfilling the performance requirements.

Pagano, Robert↗
NASA NTRS1993

Artificial intelligence for geologic mapping with imaging spectrometers

This project was a three year study at the Center for the Study of Earth from Space (CSES) within the Cooperative Institute for Research in Environmental Science (CIRES) at the University of Colorado, Boulder. The goal of this research was to develop an expert system to allow automated identification of geologic materials based on their spectral characteristics in imaging spectrometer data such as the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). This requirement was dictated by the volume of data produced by imaging spectrometers, which prohibits manual analysis. The research described is based on the development of automated techniques for analysis of imaging spectrometer data that emulate the analytical processes used by a human observer. The research tested the feasibility of such an approach, implemented an operational system, and tested the validity of the results for selected imaging spectrometer data sets.

Kruse, F. A.↗
NASA NTRS1993

Imaging Spectrometers Using Concave Holographic Gratings

Imaging spectroscopy combines the spatial attributes of imaging with the compositionally diagnostic attributes of spectroscopy. For spacebased remote sensing applications, mass, size, power, data rate, and application constrain the scanning approach. For the first three approaches, substantial savings in mass and size of the spectrometer can be achieved in some cases with a concave holographic grating and careful placement of an order-sorting filter. A hologram etched on the single concave surface contains the equivalent of the collimating, dispersing, and camera optics of a conventional grating spectrometer and provides substantial wavelength dependent corrections for spherical aberrations and a flat focal field. These gratings can be blazed to improve efficiency when used over a small wavelength range or left unblazed for broadband uniform efficiency when used over a wavelength range of up to 2 orders. More than 1 order can be imaged along the dispersion axis by placing an appropriately designed step order-sorting filter in front of the one- or two-dimensional detector. This filter can be shaped for additional aberration corrections. The VIRIS imaging spectrometer based on the broadband design provides simultaneous imaging of the entrance slit from lambda = 0.9 to 2.6 microns (1.5 orders) onto a 128 x 128 HgCdTe detector (at 77 K). The VIRIS spectrometer was used for lunar mapping with the UH 24.in telescope at Mauna Kea Observatory. The design is adaptable for small, low mass, space based imaging spectrometers.

Gradie, J.↗