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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 307 records · Page 17

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DOE OSTI2026

Towards robust laser beam propagation in atmospheric turbulence

High-fidelity optical propagation through the atmosphere is essential for free-space optical technologies, including laser-based remote sensing and optical communication. However, atmospheric turbulence severely distorts beams and compromises system performance. In this work, we employ hypergeometric-Gaussian (HyGG) vortex beams as probes to characterize and mitigate atmospheric turbulence. Using over 250,000 experimental and simulated frames, we show that refining the power spectrum density (PSD) can reduce numerical prediction errors by up to 79.8%. Concurrently, experimental observations supported by numerical simulations demonstrate that HyGG beams exhibit superior turbulence resilience across multiple metrics compared to conventional Gaussian beams, particularly in their ability to withstand over 5 times stronger turbulence while maintaining similar intensity fluctuations. These dual investigations, on both turbulence mitigation and robust beam solutions, converge to form a unified strategy for enhancing free-space optical system performance. Collectively, our findings provide new insights into light–turbulence interactions and highlight the practical utility of vortex beams under atmospheric conditions.

Zhang, Boyu↗

DOE OSTI2026

Reese Housing Power Project (Final Technical Report)

The Reese Housing Power Project is located on Tribal trust land in Colusa, CA and expands existing medium-voltage distribution to seven new households with the addition of medium-voltage cabling, step down transformers, smart meters, and street lighting for the new development. The Tribe utilized their existing Co-Generation power plant and micro grid to supply the new homes with highly reliable power with fewer interruptions and at a reduced rate compared with the local utility. The project gives the Tribe greater independence from traditional power sources and provides jobs for the community. The project reduces electric energy costs, increases Tribe self-reliance, and provides highly reliable electric power to seven tribal members’ homes. Construction of the project also provided jobs for the community.

24 POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2026

Neutron Positioning and Geometric Distortion Correction on the SNS SiPM Anger Camera

Neutron Anger cameras are scintillator-based thermal neutron detectors that utilize pixelated photosensors to read out visible light signals and position neutrons accurately They are versatile detectors that can cover large areas for diffraction instruments and offer high efficiency and sub-millimeter spatial resolution. Photomultiplier Tube (PMT) based cameras are installed on three instruments at Spallation Neutron Source (SNS). The next generation camera uses Silicon Photomultipliers (SiPMs) instead of PMTs, which allows for a more compact design and higher spatial resolution. In this report, the Gaussian least-squares position fitting method is described in detail, as well as the method used to correct for geometric distortions across the face of the camera. Results from neutron camera tests before and after the distortion correction are shown and the spatial resolution is quantified.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

NASA NTRS1974

Differential transmission of sunlight on Mars - Biological implications

A euphotic zone seems to exist at about 1 cm subsurface in the Martian epilith. At this depth, visible light is still intense enough to be utilized by conceivable photosynthetic organisms; but the germicidal ultraviolet intensities at the Martian surface have been reduced to values manageable by terrestrial life. Such euphotic zone organisms would experience moderately high Martian temperatures at equatorial latitudes and can be dispersed readily during global dust storms. During such storms the Martian euphotic zone may reach the surface. The aerosol content of the Martian atmosphere can be monitored by multiband single-line scans of the sun at large zenith angles by the Viking lander camera; and the postulated euphotic zone organisms can be searched for with the Viking lander sample arm and biology experiments.

Sagan, C.↗

NASA NTRS1979

Nephelometer evaluation for measurement of cloud parameters in earth and planetary atmospheres

Initial work was concerned with determining whether the radiation emitted from a laser source could be sufficiently collimated to provide a suitable source for a nephelometer-type instrument. It was necessary to develop a standard scatterer that could be used to evaluate the performance of a nephelometer. The possible use of a gallium arsenide diode as a radiation source also was investigated. The first of these utilized a single lens to focus the light scattered from a target onto a ring detector. The second configuration used reflecting and refracting axicons as optical-system elements. The work performed in each of these areas is described.

Ballard, G. S.↗

NASA NTRS1981

High speed techniques for synthetic aperture radar image formation

One possible approach to high speed synthetic aperture radar signal reconstruction involves the utilization of two dimensional real time spatial light modulators as recyclable replacements for photographic film in the input transducer plane of a modified synthetic aperture radar (SAR) coherent optical processor. Leading candidate spatial light modulators include modified Pockels readout optical modulators (PROM), charge coupled devices (CCD) addressed liquid crystal light valves, and CCD addressed membrane light modulators. The fundamental physical limitations affecting SAR processor performance characteristics of such real time devices are under investigation. Current research on PROM is focused on the effects of device operatonal mode, device constitutive parameters, electro-optic crystal orientation, writing wavelength, frame rate/data overwrite/presuming, erasure completeness, and image retention on the overall quality of SAR image formation. Both modulated laser scanning and intensified CRT temporal to spatial input approaches are being examined.

Psaltis, D.↗

NASA NTRS1981

Ignition and combustion: Low compression ratio, high output diesel

The feasibility of converting a spark ignition aircraft engine GTSI0-520 to compression ignition without increasing the peak combustion pressure of 1100 lbs/sq.in. was determined. The final contemplated utilized intake air heating at idle and light load and a compression ratio of about 10:1 with a small amount of fumigation (the addition of about 15% fuel into the combustion air before the cylinder). The engine used was a modification of a Continental-Teledyne gasoline engine cylinder from the GTSI0-520 supercharged aircraft engine.

Source record↗

NASA NTRS1983

A flight-test and simulation evaluation of the longitudinal final approach and landing performance of an automatic system for a light wing loading STOL aircraft

As part of a comprehensive flight-test program of STOL operating systems for the terminal area, an automatic landing system was developed and evaluated for a light wing loading turboprop aircraft. The aircraft utilized an onboard advanced digital avionics system. Flight tests were conducted at a facility that included a STOL runway site with a microwave landing system. Longitudinal flight-test results were presented and compared with available (basically CTOL) criteria. These comparisons were augmented by results from a comprehensive simulation of the controlled aircraft which included representations of navigation errors that were encountered in flight and atmospheric disturbances. Acceptable performance on final approach and at touchdown was achieved by the autoland (automatic landing) system for the moderate winds and turbulence conditions encountered in flight. However, some touchdown performance goals were marginally achieved, and simulation results suggested that difficulties could be encountered in the presence of more extreme atmospheric conditions. Suggestions were made for improving performance under those more extreme conditions.

Brown, S. C.↗

NASA NTRS1983

Velocity Visualization in Gaseous Flows

Techniques yielding simultaneous, multiple point measurements of velocity in reacting or nonreacting flow fields have the potential to significantly impact basic and applied studies of fluid mechanics. Several candidate schemes which could provide such measurement capability were investigated. The concepts utilize laser sources which lead to scattered light which can be monitored by a film based camera or a multielement solid state camera. Velocity measurements in supersonic flows using a novel Doppler modulated fluorescence concept are presented.

Hanson, R. K.↗

NASA NTRS1983

Suitability of commercially available laboratory cryogenic refrigerators to support shipboard electro-optical systems in the 10 - 77 Kelvin region

The primary development of cryogenically cooled infrared systems was accomplished by FLIR systems designed for airborne, passive night vision. Essential to the development of these FLIR systems was a family of closed cycle refrigerators which had to meet a limited envelope requirement, utilize a nonlubricated compressor module, and be light in weight. Closed cycle refrigerators accomplished the same cooling function, they use modified oil lubricated reciprocating compressors which are limited in their axis of orientation to an angle of approximately 15-20 degrees maximum from horizon.

Hansen, R. G.↗

NASA NTRS1988

Astronomy and astrophysics with the Advanced X-ray Astrophysics Facility

The optics and instruments of the Advanced X-ray Astrophysics Facility (AXAF) are described. The instrument capabilities are reviewed so that potential users of AXAF may plan supporting research in the years prior to launch. The AXAF is to be built around a large-area high-resolution grazing-incidence X-ray telescope, with a complement of imaging and spectroscopic instruments which can be maintained and/or replaced in orbit. An important feature of the AXAF is the aspect system. It utilizes solid state star cameras and fiducial lights to permit both image reconstruction (on the ground) with minimal blurring due to spacecraft and internal motions, and placement of the X-ray image on the sky to an accuracy of 1 arcsec.

Weisskopf, Martin C.↗

NASA NTRS1991

Illuminance and luminance distributions of a prototype ambient illumination system for Space Station Freedom

Preliminary results of research conducted in the late 1970's indicate that perceptual qualities of an enclosure can be influenced by the distribution of illumination within the enclosure. Subjective impressions such as spaciousness, perceptual clarity, and relaxation or tenseness, among others, appear to be related to different combinations of surface luminance. A prototype indirect ambient illumination system was developed which will allow crew members to alter surface luminance distributions within an enclosed module, thus modifying perceptual cues to match crew preferences. A traditional lensed direct lighting system was compared to the prototype utilizing the full-scale mockup of Space Station Freedom developed by Marshall Space Flight Center. The direct lensed system was installed in the habitation module with the indirect prototype deployed in the U.S. laboratory module. Analysis centered on the illuminance and luminance distributions resultant from these systems and the implications of various luminaire spacing options. All test configurations were evaluated for compliance with NASA Standard 3000, Man-System Integration Standards.

Mullican, R. C.↗

NASA NTRS1993

ER-2 investigations of lightning and thunderstorms

The primary objective of the ER-2 lightning program is to investigate relationships between lightning and storm electrification and a number of underlying and interrelated phenomena including the structure, dynamics, and evolution of thunderstorms and thunderstorm systems, precipitation distribution and amounts, atmospheric chemistry processes, and the global electric circuit. This research is motivated by the desire to develop an understanding needed for the effective utilization and interpretation of data from the Lighting Imaging Sensor (LIS), the Lightning Mapper Sensor (LMS), and other satellite-based lightning detectors planned for the late 1900's and early 2000's. These satellite lightning detection systems will be characterized by high detection efficiencies (i.e., 90 percent) and the capability to detect both intracloud and cloud-to-ground discharges during day and night. The Lightning Imaging Sensor (LIS) is being developed by NASA for the Tropical Rainfall Measuring Mission (TRMM) satellite. In the ER-2 and related investigations, the emphasis is on establishing quantitative relationships and developing practical algorithms that employ lightning data, such as could be derived from satellite observations of optical lightning emissions, as the independent variable. Significant accomplishments made during the past year are presented.

Blakeslee, Richard↗

NASA NTRS1993

Finite element analysis of a composite artificial ankle

Ultra-light carbon fiber composite materials are being utilized in artificial limbs with increasing frequency in recent years. Dr. Arthur Copes, an orthotist from Baton Rouge, Louisiana, has developed a graphite expoxy composite material artificial ankle (Copes/Bionic Ankle) that is intended to be used by amputees who require the most advanced above-and-below-the-knee prosthetic devices. The Copes/Bionic Ankle is designed to reproduce the function of the natural ankle joint by allowing the composite material to act as a spring mechanism without the use of metal mechanical parts. NASA Marshall Space Flight Center has agreed to participate in the design effort by providing the structural analysis of the artificial ankle design.

Perkins, Leigh Ann↗

NASA NTRS1992

Face-gear drives: Design, analysis, and testing for helicopter transmission applications

The use of face-gears in helicopter transmissions was explored. A light-weight, split-torque transmission design utilizing face-gears is described. Face-gear design and geometry were investigated. Topics included tooth generation, limiting inner and outer radii, tooth contact analysis, contact ratio, gear eccentricity, grinding, and structural stiffness. Design charts were developed to determine minimum and maximum face-gear inner and outer radii. An analytical study showed that the face-gear drive is relatively insensitive to gear misalignment with respect to transmission errors, but the tooth contact is affected by misalignment. A method of localizing the bearing contact to permit operation with misalignment was explored. Two new methods for grinding of the face-gear tooth surfaces were also investigated. The proper choice of shaft stiffness enabled good load sharing in the split-torque transmission design. Face-gear experimental studies were also conducted. These tests demonstrated the feasibility of face-gears in high-speed, high-load applications such as helicopter transmissions.

Litvin, F. L.↗

NASA NTRS1991

An Isotope-Powered Thermal Storage unit for space applications

An Isotope-Powered Thermal Storage Unit (ITSU), that would store and utilize heat energy in a 'pulsed' fashion in space operations, is described. Properties of various radioisotopes are considered in conjunction with characteristics of thermal energy storage materials, to evaluate possible implementation of such a device. The utility of the unit is discussed in light of various space applications, including rocket propulsion, power generation, and spacecraft thermal management.

Lisano, Michael E.↗

NASA NTRS1994

Adjustable Optical-Fiber Attenuator

Adjustable fiber-optic attenuator utilizes bending loss to reduce strength of light transmitted along it. Attenuator functions without introducing measurable back-reflection or insertion loss. Relatively insensitive to vibration and changes in temperature. Potential applications include cable television, telephone networks, other signal-distribution networks, and laboratory instrumentation.

Buzzetti, Mike F.↗

NASA NTRS1995

Gamma Ray Burst Optical Counterpart Search Experiment (GROCSE)

GROCSE (Gamma-Ray Optical Counterpart Search Experiments) is a system of automated telescopes that search for simultaneous optical activity associated with gamma ray bursts in response to real-time burst notifications provided by the BATSE/BACODINE network. The first generation system, GROCSE 1, is sensitive down to Mv (approximately) 8.5 and requires an average of 12 seconds to obtain the first images of the gamma ray burst error box defined by the BACODINE trigger. The collaboration is now constructing a second generation system which has a 4 second slewing time and can reach Mv (approximately) 14 with a 5 second exposure. GROCSE 2 consists of 4 cameras on a single mount. Each camera views the night sky through a commercial Canon lens (f/1.8, focal length 200 mm) and utilizes a 2K x 2K Loral CCD. Light weight and low noise custom readout electronics were designed and fabricated for these CCDs. The total field of view of the 4 cameras is 17.6 x 17.6 (degree). GROCSE 2 will be operated by the end of 1995. In this paper, the authors present an overview of the GROCSE system and the results of measurements with a GROCSE 2 prototype unit.

Park, H. S.↗