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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 757 records · Page 42
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

A proof of concept investigation: A unique mobility spectrometer for In Situ diagnostics of positive and negative ion distributions in the mesosphere and lower ionosphere

We have carried out a proof-of-concept development and test effort that not only promises the reduction of parasitic effects of surface contamination (therefore increasing the integrity of 'in situ' measurements in the 60-130 km regime), but promises a uniquely expanded measurement set that includes electron densities, plasma conductivities, charged-particle mobilities, and mass discrimination of positive and negative ion distributions throughout the continuum to free-molecular-flow regimes. Three different sensor configurations were designed, built and tested, along with specialized driving voltage, electrometer and channeltron control electronics. The individual systems were tested in a variety of simulated space environments ranging from pressures near the continuum limit of 100 mTorr to the collisionless regime at 10(exp -6) Torr. Swept modes were initially employed to better understand ion optics and ion 'beam' losses to end walls and to control electrodes. This swept mode also helped better understand and mitigate the influences of secondary electrons on the overall performance of the PIMS design concept. Final results demonstrated the utility of the concept in dominant single-ion plasma environments. Accumulated information, including theoretical concepts and laboratory data, suggest that multi-ion diagnostics are fully within the instrument capabilities and that cold plasma tests with minimized pre-aperture sheath acceleration are the key ingredients to multi-ion success.

Szuszczewicz, Edward P.↗
NASA NTRS1998

Modulated Source Interferometry with Combined Amplitude and Frequency Modulation

An improved interferometer is produced by modifying a conventional interferometer to include amplitude and/or frequency modulation of a coherent light source at radio or higher frequencies. The phase of the modulation signal can be detected in an interfering beam from an interferometer and can be used to determine the actual optical phase of the beam. As such, this improvement can be adapted to virtually any two-beam interferometer, including: Michelson, Mach-Zehnder, and Sagnac interferometers. The use of an amplitude modulated coherent tight source results in an interferometer that combines the wide range advantages of coherent interferometry with the precise distance measurement advantages of white light interferometry.

Gutierrez, Roman C.↗
NASA NTRS1999

Method and Apparatus for Improved Spatial Light Modulation

A method and apparatus for modulating a light beam in an optical processing system is described. Preferably, an electrically-controlled polarizer unit and/or an analyzer unit are utilized in combination with a spatial light modulator and a controller. Preferably, the spatial light modulator comprises a pixelated birefringent medium such as a liquid crystal video display. The combination of the electrically controlled polarizer unit and analyzer unit make it simple and fast to reconfigure the modulation described by the Jones matrix of the spatial light modulator. A particular optical processing objective is provided to the controller. The controller performs calculations and supplies control signals to the polarizer unit, the analyzer unit, and the spatial light modulator in order to obtain die optical processing objective.

Colin, Soutar↗
NASA NTRS2000

Method and Apparatus for Improved Spatial Light Modulation

A method and apparatus for modulating a light beam in an optical processing system is described. Preferably, an electrically-controlled polarizer unit and/or an analyzer unit are utilized in combination with a spatial light modulator and a controller. Preferably, the spatial light modulator comprises a pixelated birefringent medium such as a liquid crystal video display. The combination of the electrically controlled polarizer unit and analyzer unit make it simple and fast to reconfigure the modulation described by the Jones matrix of the spatial light modulator. A particular optical processing objective is provided to the controller. The controller performs calculations and supplies control signals to the polarizer unit, the analyzer unit, and the spatial light modulator in order to obtain the optical processing objective.

Soutar, Colin↗
NASA NTRS2006

Single-Pulse Multi-Point Multi-Component Interferometric Rayleigh Scattering Velocimeter

A simultaneous multi-point, multi-component velocimeter using interferometric detection of the Doppler shift of Rayleigh, Mie, and Rayleigh-Brillouin scattered light in supersonic flow is described. The system uses up to three sets of collection optics and one beam combiner for the reference laser light to form a single collimated beam. The planar Fabry-Perot interferometer used in the imaging mode for frequency detection preserves the spatial distribution of the signal reasonably well. Single-pulse multi-points measurements of up to two orthogonal and one non-orthogonal components of velocity in a Mach 2 free jet were performed to demonstrate the technique. The average velocity measurements show a close agreement with the CFD calculations using the VULCAN code.

Bivolaru, Daniel↗
NASA NTRS2007

NASA Tech Briefs, April 2007

Topics include: Wearable Environmental and Physiological Sensing Unit; Broadband Phase Retrieval for Image-Based Wavefront Sensing; Filter Function for Wavefront Sensing Over a Field of View; Iterative-Transform Phase Retrieval Using Adaptive Diversity; Wavefront Sensing With Switched Lenses for Defocus Diversity; Smooth Phase Interpolated Keying; Maintaining Stability During a Conducted-Ripple EMC Test; Photodiode Preamplifier for Laser Ranging With Weak Signals; Advanced High-Definition Video Cameras; Circuit for Full Charging of Series Lithium-Ion Cells; Analog Nonvolatile Computer Memory Circuits; JavaGenes Molecular Evolution; World Wind 3D Earth Viewing; Lithium Dinitramide as an Additive in Lithium Power Cells; Accounting for Uncertainties in Strengths of SiC MEMS Parts; Ion-Conducting Organic/Inorganic Polymers; MoO3 Cathodes for High-Temperature Lithium Thin-Film Cells; Counterrotating-Shoulder Mechanism for Friction Stir Welding; Strain Gauges Indicate Differential-CTE-Induced Failures; Antibodies Against Three Forms of Urokinase; Understanding and Counteracting Fatigue in Flight Crews; Active Correction of Aberrations of Low-Quality Telescope Optics; Dual-Beam Atom Laser Driven by Spinor Dynamics; Rugged, Tunable Extended-Cavity Diode Laser; Balloon for Long-Duration, High-Altitude Flight at Venus; and Wide-Temperature-Range Integrated Operational Amplifier.

Source record↗
NASA NTRS2003

Detecting Moving Targets by Use of Soliton Resonances

A proposed method of detecting moving targets in scenes that include cluttered or noisy backgrounds is based on a soliton-resonance mathematical model. The model is derived from asymptotic solutions of the cubic Schroedinger equation for a one-dimensional system excited by a position-and-time-dependent externally applied potential. The cubic Schroedinger equation has general significance for time-dependent dispersive waves. It has been used to approximate several phenomena in classical as well as quantum physics, including modulated beams in nonlinear optics, and superfluids (in particular, Bose-Einstein condensates). In the proposed method, one would take advantage of resonant interactions between (1) a soliton excited by the position-and-time-dependent potential associated with a moving target and (2) eigen-solitons, which represent dispersive waves and are solutions of the cubic Schroedinger equation for a time-independent potential.

Zak, Michael↗
NASA NTRS2018

Testing with the Laser-Enhanced Arc Jet Facility (LEAF) at NASA Ames Research Center

NASA's new Laser-Enhanced Arcjet Facility (LEAF) employs 200 kilowatts of continuous-wave fiber lasers, combined with a 60-megawatt arc plasma jet, to simulate the combined radiative and convective heating is now operational and Orion heat-shield material is undergoing testing. This upgrade to the existing Interaction Heating Facility (IHF) involves the addition of high-power fiber lasers that project 1070nm radiative energy into the existing vacuum chamber. The optically expanded laser beam enters a side window of the test chamber to form either a uniform 150 x 150 mm or a 425 x 425 mm square spot on a wedge-shaped model holder. Combined heating levels of up to 180 W/cm2 convective with either 300 W/cm2 or 100 W/cm2 are achievable. This allows the arc jet and lasers to simulate dynamic entry-heating profiles encountered during entry by the Orion crew capsule for the lunar return conditions. New computational investigations are underway to explore testing with the objective of defining ablative material failure limit. Typical arc-jet testing is performed with test article that are stagnation or wedge geometries. The existing convective heating test facility combined with test article design limits how high a combined shear, heat-flux and pressure conditions can be achieved. With the addition of laser power of 200 kW, much higher combined conditions of high heat-flux, pressure and shear is achievable on a wedge or a swept-cylinder article. Such testing possibilities will allow us to progressively increase the combined conditions and explore when an ablative TPS material may fail. The presentation provides an overview of the LEAF and present results from the on-going Orion Testing.

Venkatapathy, Ethiraj↗
NASA NTRS2020

Dynamic Modeling, Simulation, and Analysis of Orbiting Sample Capture for Potential Mars Sample Return

The current notional architecture for the Mars Sample Return (MSR) campaign would require autonomous on-orbit rendezvous and capture of a sample container after it has been delivered to Mars orbit by a preceding MSR mission. As part of the complete orbital payload known as the Capture, Contain, and Return System (CCRS), a concept has been developed for autonomously sensing and capturing this Orbiting Sample (OS) container. The concept, comprised of a capture mechanism and multiple optical break-beam arrays, would detect and enclose the OS into CCRS, and engage a dust-tight seal to prevent the escape of the OS or other unsterilized particles. A challenging goal for the system is to close the lid prior to the OS coming into physical contact after entering CCRS in order to reduce the risk of unsterilized Mars particles on the surface of the OS from contaminating the outside of the spacecraft. The mechanical and sensor performance requirements were driven by the broader architecture of CCRS, OS rendezvous parameters, and Planetary Protection requirements regarding the interaction and handling of the OS. The mechanism and break-beam array concepts were designed accordingly, and kinematic simulations of the mechanism’s behavior, combined with a Monte-Carlo simulation of OS rendezvous/collision behaviors and corresponding breakbeam sensor responses verify compliance.

Ishigo, Alyssa↗
NASA NTRSDate not supplied

Indigenous Organic Matter Associated with Unusual Low Temperature Aqueous Secondary Phases in the Mars Meteorite Nakhla

In freshly fractured chips of the Mars meteorite Nakhla, we found carbonaceous phases intimately associated with secondary aqueous alteration phases, both mineral and amorphous, interpreted to have formed through the low-temperature, mineral-water dissolution of the host Martian basalt.We have characterized the nature of carbonaceous matter and spatially associated secondary phases within Nakhla using a multidisciplinary suite of optical and electron beam instrumentation(Thomas-Keprta et al., 2022). Secondary Phases: The preserved secondary mineral phases are best described as ‘juvenile’ hydrated amorphous silica formed when water interacts with mafic rocks. Although amorphous silica on Earth rarely persists through geologic time due to alteration into other phases, e.g.,microcrystalline opal-CT and eventually quartz, the lack of maturation of primarily amorphous silica with embedded nano phase ferrihydrite in Nakhla infers these phases formed in a limited water environment by low temperature, circumneutral pH fluids stabilized by the presence of coexisting amorphous silica.Additionally, we report the presence of the ferrous hydroxycarbonate mineral chukanovite (Fe2(OH)2CO3)within some of the secondary mineral aggregates studied. Organic Matter:Indigenous Nakhla carbonaceous matter is present both in condensed phases and in a dispersed state spatially associated with secondary alteration phases. In the former, discrete refractory micron to submicron assemblages were identified that appear macromolecular in nature and, in several cases, associated with F and, in one case, significant N. While organically bound Fhas yet to be detected remotely on Mars, the identification of organic N within one of the carbonaceous phases is considered a prerequisite for Martian astrobiological potential. Summary: Neither the intimate association of carbonaceous matter with secondary phases nor the identification of chukanovite have been previously reported in any of the Martian meteorites.A variety of habitability-related metastable solid-phase, oxidation-reduction, and organic-molecular sample attributes in Nakhla formed hundreds of millions of years ago near Mars’ surface; these alteration products persisted on Mars until very recentlyand resemble the amorphous materials observed at Gale crater by Mars Science Laboratory CuriosityRover (Rampe et al., 2020).Similar phases may be expected to occur elsewhere on Mars (e.g., Jezerocrater). References: Rampe E. B. et al.(2020) Mineralogy and geochemistry of sedimentary rocks and eolian sediments in Gale crater, Mars: A review after six Earth years of exploration with Curiosity.Geochemistry80, 125605; Thomas-Keprta K.L. et al. (2022) Indigenous carbon-rich matter associated with unusual aqueous alteration features in Nakhla: Complex formation and preservation history. Geochim. et Cosmochim. Acta320, 41-78 (online).

Mars meteorite↗
NASA NTRSDate not supplied

Solid-state Laser Development for the in Situ Spectroscopic Europa Explorer Instrument

The in Situ Spectroscopic Europa Explorer (iSEE) instrument is an ultra-compact laser-enabled Raman spectrometer instrument that meets the top-level science requirements for multiple future planetary in situ missions to explore the surface and atmospheric chemistry of planetary bodies across the Solar System. Enceladus, Europa, the Moon, Mars, and Venus are some of the primary targets for future NASA missions to search for extraterrestrial life and potentially habitable environments beyond Earth, further our understanding of the timing and formation of the Solar System and identify potentially viable economic resources such as water and/or valuable metal assets. We report on the advancement and space flight qualification of a compact, robust, solid-state laser operating at 515 nm that serves as the excitation source for the iSEE investigation. The iSEE instrument is being developed under a NASA Maturation of Instruments for Solar System Exploration (MatISSE) program. The iSEE laser is a diode pumped 1030 nm Yb:YAG microchip laser with a second harmonic generator to achieve an output wavelength of 515 nm and coupled to a multi-mode fiber for delivery to the Raman spectrometer probe. The fundamental 1030 nm laser operates at a pulse repetition frequency (PRF) of 1-10 kHz with pulse energy of 95 μJ and ~800 ps pulse width. A 15 mm long Type II KTP crystal is used for second harmonic generation from 1030 nm to 515 nm. The residual fundamental 1030 nm is separated from the 515 nm beam using a pair of dichroic filters. A focusing lens couples the 515 nm beam to the optical fiber to produce an output laser pulse energy of 20 μJ. A custom vacuum fiber feedthrough assembly was designed with two 105 μm core fibers, and two 200 μm core fibers. One fiber is needed for coupling the laser to the iSEE instrument, and the additionally fibers provide redundancy and design flexibility. The laser enclosure is pressurized with >1 atm of clean dry air. The laser has been designed to minimize the size, weight, and power (SWaP) for a lander instrument with minimal resources. The laser will go through environmental testing including vibration and thermal vacuum testing for space flight qualification. Here we discuss the design, trade studies, performance, and environmental qualificationtesting of the iSEE laser.

Solid state laser, Raman spectrometer, visible las↗
DOE OSTI2024

Start-to-End Optics Validation of FFA-Based Energy Upgrade to CEBAF

This project will thoroughly validate the optics for a proof-of-principal, proposed FFA-based energy upgrade for CEBAF. This upgrade consists of CBETA-like FFA arcs in place of the highest-energy recirculating arcs in the machine, allowing for several more passes through the linacs. This should enable a highest beam energy of 20-24 GeV. This LDRD project will include Start-to-End (S2E) optics and beam dynamics simulations, beam loss and power deposition, and indicate requirements for updates to diagnostics.

43 PARTICLE ACCELERATORS↗
NASA NTRS1972

A symmetrical laser Doppler velocity meter and its application to turbulence characterization

A symmetrical method of optical heterodyning of the Doppler shifted scattered laser radiation developed for velocity measurements with a minimal instrumental spectral broadening and a high signal-to-noise ratio. The method employs two laser beams incident on the moving scatterer and does not use any reference beam for heterodyning. The Doppler signal frequency is independent of the scattering angle and the signal possesses no receiving aperture broadening. Optical alignment is simple. Typical values of the instrumental spectral broadening were approximately 0.8 percent of the center frequency of the Doppler signal, and the signal-to-noise ratio was approximately 25 dB, obtained from an air flow system using submicron dioctylphthalate scattering aerosol. Experimental and theoretical studies were made on the characteristics of the Doppler signal and the effect of system parameters in turbulent flow measurement. The optimization process involved in the beam optics and in the use of a spatial filter is described. For localized flow measurement in any direction of the three-dimensional orthogonal coordinates, the system, using uncorrected optical components, had a sensing volume which can be described by a sensitive length of 600 microns and a diameter of 100 microns.

Mazumder, M. K.↗
NASA NTRS2007

Operations at the JPL OCTL Telescope

The JPL Optical Communications Telescope Laboratory (OCTL) is a 200 sq-m located at 2.2.km altitude in Wrightwood California and houses a state-of-the-art 1-m telescope. The OCTL team is involved in the development of operational strategies for ground-to-space laser beam propagation for future NASA optical communications missions. Strategies include safe beam propagation through navigable air space, line of sight optical attenuation monitoring, adaptive optics, and multi-beam scintillation mitigation. This paper presents the results of recent operations at the OCTL facility including telescope characterization data and laser beam propagation experiments to Earth-orbiting retro-reflecting satellites; experiments that validate the telescope's tracking and blind-pointing performance and safe laser beam transmission procedures for propagating through navigable airspace.

optical communications↗
NASA NTRS1990

The status of cesium beam frequency standards

There has been a lot of progress in cesium beam frequency standards in the last few years some of which will be reported here. Optical pumping is being pursued actively in a number of laboratories. Optically slowed and cooled beams have been demonstrated as well as traps for cold neutral atoms. The microwave cavity performance with regard to local phase shift at the beam holes was improved by use of carefully designed and built ring structures for the cavity ends. Work is being done on improvements in electronics with some emphasis on use of digital circuitry and microprocessors. The frequency pulling due to microwave Delta M = +/- 1 transitions (Ramsey pulling) was analyzed and shown to be important. Status of cesium beam frequency standards in some of the laboratories as well as some of the commercial work is discussed. Optical pumping and detection are discussed.

Cutler, Leonard S.↗
NASA NTRS1982

Collimated beam manifold with the number of output beams variable at a given output angle

An optical manifold is described which transforms a collimated beam, such as a laser beam, into a plurality of parallel beams having uniform intensity or having a desired intensity ratio. The manifold comprises an optical substrate coated on its rear surface with a fully reflective layer and on its front surface with a partially reflecting layer having a reflectivity gradient. An input collimated beam entering the rear surface and impinging on the front surface is reflected, multiply between the front and rear surfaces producing a plurality of parallel beams that emerge from the front surface. The intensities of the emerging beams have a relationship that depends on the reflectivity of the front surface at the points where the beams emerge. By properly selecting the reflectivity gradient, the emerging beams have uniform intensity or a desired intensity ratio.

Campbell, C. W.↗