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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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Volumetric 3D Display System with Static Screen

Current display technology has relied on flat, 2D screens that cannot truly convey the third dimension of visual information: depth. In contrast to conventional visualization that is primarily based on 2D flat screens, the volumetric 3D display possesses a true 3D display volume, and places physically each 3D voxel in displayed 3D images at the true 3D (x,y,z) spatial position. Each voxel, analogous to a pixel in a 2D image, emits light from that position to form a real 3D image in the eyes of the viewers. Such true volumetric 3D display technology provides both physiological (accommodation, convergence, binocular disparity, and motion parallax) and psychological (image size, linear perspective, shading, brightness, etc.) depth cues to human visual systems to help in the perception of 3D objects. In a volumetric 3D display, viewers can watch the displayed 3D images from a completely 360 view without using any special eyewear. The volumetric 3D display techniques may lead to a quantum leap in information display technology and can dramatically change the ways humans interact with computers, which can lead to significant improvements in the efficiency of learning and knowledge management processes. Within a block of glass, a large amount of tiny dots of voxels are created by using a recently available machining technique called laser subsurface engraving (LSE). The LSE is able to produce tiny physical crack points (as small as 0.05 mm in diameter) at any (x,y,z) location within the cube of transparent material. The crack dots, when illuminated by a light source, scatter the light around and form visible voxels within the 3D volume. The locations of these tiny voxels are strategically determined such that each can be illuminated by a light ray from a high-resolution digital mirror device (DMD) light engine. The distribution of these voxels occupies the full display volume within the static 3D glass screen. This design eliminates any moving screen seen in previous approaches, so there is no image jitter, and has an inherent parallel mechanism for 3D voxel addressing. High spatial resolution is possible with a full color display being easy to implement. The system is low-cost and low-maintenance.

Geng, Jason↗
NASA NTRS1993

Power console development for NASA's electric propulsion outreach program

NASA LeRC is developing a 30 cm diameter xenon ion thruster for auxiliary and primary propulsion applications. To maximize expectations for user-acceptance of ion propulsion technology, NASA LeRC, through their Electric Propulsion Outreach Program, is providing sectors of industry with portable power consoles for operation of 5 KW-class xenon ion thrusters. This power console provides all necessary functions to permit thruster operations over a 0.5-5 KW envelope under both manual and automated control. These functions include the following: discharge, cathode heater, neutralizer keeper, and neutralizer heater currents, screen and accelerator voltages, and a gas feed system to regulate and control propellant flow to the thruster. An electronic circuit monitors screen and accelerator currents and controls arcing events. The power console was successfully integrated with the NASA 30 cm thruster.

Pinero, Luis R.↗
NASA NTRS1980

Study of surge current effects on solid tantalum capacitors

Results are presented of a 2,000 hour cycled life test program conducted to determine the effect of short term surge current screening on approximately 47 micron f/volt solid tantalum capacitors. The format provides average values and standard deviations of the parameters, capacitance, dissipation factor, and equivalent series resistance at 120 Hz, 1KHz, abd 40 KHz.

Source record↗
NASA NTRS2000

Overexpression of Human Bone Alkaline Phosphatase in Pichia Pastoris

The Pichiapastoris expression system was utilized to produce functionally active human bone alkaline phosphatase in gram quantities. Bone alkaline phosphatase is a key enzyme in bone formation and biomineralization, yet important questions about its structural chemistry and interactions with other cellular enzymes in mineralizing tissues remain unanswered. A soluble form of human bone alkaline phosphatase was constructed by deletion of the 25 amino acid hydrophobic C-terminal region of the encoding cDNA and inserted into the X-33 Pichiapastoris strain. An overexpression system was developed in shake flasks and converted to large-scale fermentation. Alkaline phosphatase was secreted into the medium to a level of 32mgAL when cultured in shake flasks. Enzyme activity was 12U/mg measured by a spectrophotometric assay. Fermentation yielded 880mgAL with enzymatic activity of 968U/mg. Gel electrophoresis analysis indicates that greater than 50% of the total protein in the fermentation is alkaline phosphatase. A purification scheme has been developed using ammonium sulfate precipitation followed by hydrophobic interaction chromatography. We are currently screening crystallization conditions of the purified recombinant protein for subsequent X-ray diffraction analyses. Structural data should provide additional information on the role of alkaline phosphatase in normal bone mineralization and in certain bone mineralization anomalies.

Karr, Laurel↗
NASA NTRS2001

B and F Signal Conditioner Checkout Unit

ATK Thiokol Propulsion, Test Services uses B&F Signal Conditioning units to provide excitation power and shunt calibration information to the data recording systems. Gage measurements such as force, temperature, pressure, strain, etc. are recorded using this equipment. Approximately 2500 reusable instrumentation B&F Signal Conditioning units were purchased over an interval from 1978 to 1988 at a cost of around $1000 each. Through use and over time, the relay contacts on the signal conditioning mode cards have become corroded, resulting in excessive contact resistance. This causes inaccurate and inconsistent calibration data and could jeopardize the test results. These signal conditioning cards are needed for product testing for an estimated five more years, therefore, it is necessary to develop a solution to isolate the malfunctioning units for repair. The current screening method requires Test Area technicians to check cards manually, however the connections and measurements required for this process are inefficient and time consuming. To resolve this problem, funding was approved to design and build two B&F Signal Conditioner Checkout Units. Each unit will allow technicians to test relay contact resistance on signal conditioning mode cards before they are installed for data collection procedures. This tool will allow Test Area to resolve calibration accuracy problems and extend the life of the data acquisition equipment, as well as save troubleshooting time for the technicians.

Magleby, Alyssa↗
NASA NTRS2012

Superconducting Effects in Optimization of Magnetic Penetration Thermometers for X-ray Microcalorimeters

We have made high resolution x-ray microcalorimeters using superconducting MoAu bilayers and Nb meander coils. The temperature sensor is a Magnetic Penetration Thermometer (MPT). Operation is similar to metallic magnetic calorimeters, but instead of the magnetic susceptibility of a paramagnetic alloy, we use the diamagnetic response of the superconducting MoAu to sense temperature changes in an x-ray absorber. Flux-temperature responsivtty can be large for small sensor heat capacity, with enough dynamic range for applications. We find models of observed flux-temperature curves require several effects to explain flux penetration or expulsion in the microscopic devices. The superconductor is non-local, with large coherence length and weak pinning of flux. At lowest temperatures, behavior is dominated by screening currents that vary as a result of the temperature dependence of the magnetic penetration depth, modified by the effect of the nonuniformity of the applied field occurring on a scale comparable to the coherence length. In the temperature regime where responslvity is greatest, spadal variations in the order parameter become important: both local variations as flux enters/leaves the film and an intermediate state is formed, and globally as changing stability of the electrical circuit creates a Meissner transition and flux is expelled/penetrates to minimize free energy.

Stevenson, Thomas R.↗
NASA NTRS2011

Magnetic Penetration Effects in Small Superconducting Devices

The temperature dependent behavior of a superconducting body in an applied magnetic field involves flux penetration/expulsion both from screening currents (within a magnetic penetration depth) and variations in the superconducting order parameter (locally to form vortices or a mixed state, or globally in the Meissner effect). The temperature dependence of the magnetic penetration depth, in particular, has been used to make highly sensitive macroscopic thermometers. For the microscopic device volumes required in sensitive low temperature photon detectors, properties of actual thin film materials, non-uniformity of applied magnetic fields, and the influence of measurement circuit dynamics are complicating factors. We discuss the various penetration effects as demonstrated in a particularly promising combination of material and geometry that we have used to make sensitive x-ray microcalorimeters.

Stevenson, T. R.↗
NASA NTRS2004

Enhanced Images for Checked and Carry-on Baggage and Cargo Screening

The current X-ray systems used by airport security personnel for the detection of contraband, and objects such as knives and guns that can impact the security of a flight, have limited effect because of the limited display quality of the X-ray images. Since the displayed images do not possess optimal contrast and sharpness, it is possible for the security personnel to miss potentially hazardous objects. This problem is also common to other disciplines such as medical Xrays, and can be mitigated, to a large extent, by the use of state-of-the-art image processing techniques to enhance the contrast and sharpness of the displayed image. The NASA Langley Research Center's Visual Information Processing Group has developed an image enhancement technology that has direct applications to this problem of inadequate display quality. Airport security X-ray imaging systems would benefit considerably by using this novel technology, making the task of the personnel who have to interpret the X-ray images considerably easier, faster, and more reliable. This improvement would translate into more accurate screening as well as minimizing the screening time delays to airline passengers. This technology, Retinex, has been optimized for consumer applications but has been applied to medical X-rays on a very preliminary basis. The resultant technology could be incorporated into a new breed of commercial x-ray imaging systems which would be transparent to the screener yet allow them to see subtle detail much more easily, reducing the amount of time needed for screening while greatly increasing the effectiveness of contraband detection and thus public safety.

Woodell, Glenn↗
NASA NTRS2004

Enhanced Images for Checked and Carry-on Baggage and Cargo Screening

The current X-ray systems used by airport security personnel for the detection of contraband, and objects such as knives and guns that can impact the security of a flight, have limited effect because of the limited display quality of the X-ray images. Since the displayed images do not possess optimal contrast and sharpness, it is possible for the security personnel to miss potentially hazardous objects. This problem is also common to other disciplines such as medical X-rays, and can be mitigated, to a large extent, by the use of state-of-the-art image processing techniques to enhance the contrast and sharpness of the displayed image. The NASA Langley Research Centers Visual Information Processing Group has developed an image enhancement technology that has direct applications to this problem of inadequate display quality. Airport security X-ray imaging systems would benefit considerably by using this novel technology, making the task of the personnel who have to interpret the X-ray images considerably easier, faster, and more reliable. This improvement would translate into more accurate screening as well as minimizing the screening time delays to airline passengers. This technology, Retinex, has been optimized for consumer applications but has been applied to medical X-rays on a very preliminary basis. The resultant technology could be incorporated into a new breed of commercial x-ray imaging systems which would be transparent to the screener yet allow them to see subtle detail much more easily, reducing the amount of time needed for screening while greatly increasing the effectiveness of contraband detection and thus public safety.

Woodell, Glen↗
NASA NTRS1994

The field of a screened magnetic dipole

The purpose of this note is to quantitatively study the asymptotic behavior of the dipole magnetic field in the tail region of a paraboloidal or cylindrical model of the magnetosphere, assuming the complete screening of the internal field by magnetopause currents. This screening assumption is equivalent to imposing the boundary condition that the normal component of the magnetic field is zero at the magnetopause. With this boundary condition, the screened dipole field falls off exponentially with distance down the tail, in sharp constrast to the bare dipole field. Analytic expressions for a cylindrical and paraboloidal magnetopause are given.

Greene, J. M.↗
NASA NTRS2006

Operational and Research Musculoskeletal Summit: Summit Recommendations

The Medical Informatics and Health Care Systems group in the Office of Space Medicine at NASA Johnson Space Center (JSC) has been tasked by NASA with improving overall medical care on the International Space Station (ISS) and providing insights for medical care for future exploration missions. To accomplish this task, a three day Operational and Research Musculoskeletal Summit was held on August 23-25th, 2005 at Space Center Houston. The purpose of the summit was to review NASA#s a) current strategy for preflight health maintenance and injury screening, b) current treatment methods in-flight, and c) risk mitigation strategy for musculoskeletal injuries or syndromes that could occur or impact the mission. Additionally, summit participants provided a list of research topics NASA should consider to mitigate risks to astronaut health. Prior to the summit, participants participated in a web-based pre-summit forum to review the NASA Space Medical Conditions List (SMCL) of musculoskeletal conditions that may occur on ISS as well as the resources currently available to treat them. Data from the participants were compiled and integrated with the summit proceedings. Summit participants included experts from the extramural physician and researcher communities, and representatives from NASA Headquarters, the astronaut corps, JSC Medical Operations and Human Adaptations and Countermeasures Offices, Glenn Research Center Human Research Office, and the Astronaut Strength, Conditioning, and Reconditioning (ASCR) group. The recommendations in this document are based on a summary of summit discussions and the best possible evidence-based recommendations for musculoskeletal care for astronauts while on the ISS, and include recommendati ons for exploration class missions.

Scheuring, Richard A.↗
NASA NTRSDate not supplied

Automating Maneuvers: Considerations for Collision Avoidance

As more space operators implement large constellations of spacecraft, automating orbit maintenance maneuvers becomes a key feature of their operations concept to ensure that the workload is manageable. However the practice of performing a maneuver without sharing the plan with other nearby spacecraft causes a risk that two spacecraft will collide, not only destroying the spacecraft involved, but creating debris that will affect all other spacecraft using that orbit regime. In order to share the maneuver plan, a predicted ephemeris file containing the maneuver must be sent to a central authority to screen against predicted trajectories of all other on-orbit objects to determine where and when close approaches may occur that need to be mitigated. Currently the screening authority used by US operators is the 19th Space Defense Squadron. However the conjunction screening process in use by the 19th was developed over 30 years ago and was not designed with automation in mind, so screenings are performed once every 8 hours, meaning that spacecraft using automated maneuvering need to allow 16 hours to share their maneuver plan via the screening process. Many operators assume that automated maneuver planning must be real-time; however this time between planning and execution to allow for screening is possible if planned for during system design. In an effort to speed up the screening process, NASA has developed a prototype system for performing near-real-time screenings. This prototype system was necessitated to support the NASA Starling mission, a constellation of 4 cubesats that planned to fly at the same altitude as the SpaceX Starlink constellation, both performing automated maneuvering. Without screening of the planned maneuvers, the two constellations risked a collision. Once converted from a prototype to an operational system, this capability will greatly help smallsats, for example those that are planning to test propulsive capabilities, by allowing fast turnaround feedback to ensure safety form collision with other objects. This paper describes the existing CA process, the prototype real-time capability, and results from the experiment that tested the prototype.

Matthew Hejduk↗
NASA NTRSDate not supplied

Automating Maneuvers: Considerations for Collision Avoidance

As more space operators implement large constellations of spacecraft, automating orbit maintenance maneuvers becomes a key feature of their operations concept to ensure that the workload is manageable. However, the practice of performing a maneuver without sharing the plan with other nearby spacecraft causes a risk that two spacecraft will collide, not only destroying the spacecraft involved, but creating debris that will affect all other spacecraft using that orbit regime. In order to share the maneuver plan, a predicted ephemeris file containing the maneuver must be sent to a central authority to screen against predicted trajectories of all other on-orbit objects to determine where and when close approaches will occur that may need to be mitigated. Currently the screening authority used by US operators is the 19th Space Defense Squadron; screenings are performed once every 8 hours, meaning that spacecraft using automated maneuvering need to allow 16 hours to share their maneuver plan via the screening process in advance of maneuver execution in case one screening is missed and the next needs to be used. In an effort to speed up the screening process to benefit spacecraft using automated maneuvering, a prototype system for performing near-real-time screenings has been developed in support of the NASA Starling mission, a constellation of four cubesats that fly at the same altitude as the SpaceX Starlink constellation. Both of these constellations perform automated maneuvering, so without screening the planned maneuvers before execution, the two constellations would risk a collision. This paper describes the traditional conjunction assessment (CA) process, the prototype real-time CA screening capability, plans for the experiment to test the prototype, and next steps.

conjunction assessment↗
NASA NTRSDate not supplied

Automating Maneuvers: Considerations for Collision Avoidance

As more space operators implement large constellations of spacecraft, automating orbit maintenance maneuvers becomes a key feature of their operations concept to ensure that the workload is manageable. However, the practice of performing a maneuver without sharing the plan with other nearby spacecraft causes a risk that two spacecraft will collide, not only destroying the spacecraft involved, but creating debris that will affect all other spacecraft using that orbit regime. In order to share the maneuver plan, a predicted ephemeris file containing the maneuver must be sent to a central authority to screen against predicted trajectories of all other on-orbit objects to determine where and when close approaches will occur that may need to be mitigated. Currently the screening authority used by US operators is the 19th Space Defense Squadron; screenings are performed once every 8 hours, meaning that spacecraft using automated maneuvering need to allow 16 hours to share their maneuver plan via the screening process in advance of maneuver execution in case one screening is missed and the next needs to be used. In an effort to speed up the screening process to benefit spacecraft using automated maneuvering, a prototype system for performing near-real-time screenings has been developed in support of the NASA Starling mission, a constellation of four cubesats that fly at the same altitude as the SpaceX Starlink constellation. Both of these constellations perform automated maneuvering, so without screening the planned maneuvers before execution, the two constellations would risk a collision. This paper describes the traditional conjunction assessment (CA) process, the prototype real-time CA screening capability, plans for the experiment to test the prototype, and next steps.

conjunction assessment↗
NASA NTRS2001

Performance Evaluation of Titanium Ion Optics for the NASA 30 cm Ion Thruster

The results of performance tests with titanium ion optics were presented and compared to those of molybdenum ion optics. Both titanium and molybdenum ion optics were initially operated until ion optics performance parameters achieved steady state values. Afterwards, performance characterizations were conducted. This permitted proper performance comparisons of titanium and molybdenum ion optics. Ion optics' performance A,as characterized over a broad thruster input power range of 0.5 to 3.0 kW. All performance parameters for titanium ion optics of achieved steady state values after processing 1200 gm of propellant. Molybdenum ion optics exhibited no burn-in. Impingement-limited total voltages for titanium ion optics where up to 55 V greater than those for molybdenum ion optics. Comparisons of electron backstreaming limits as a function of peak beam current density for molybdenum and titanium ion optics demonstrated that titanium ion optics operated with a higher electron backstreaming limit than molybdenum ion optics for a given peak beam current density. Screen grid ion transparencies for titanium ion optics were as much as 3.8 percent lower than those for molybdenum ion optics. Beam divergence half-angles that enclosed 95 percent of the total beam current for titanium ion optics were within 1 to 3 deg. of those for molybdenum ion optics. All beam divergence thrust correction factors for titanium ion optics were within 1 percent of those with molybdenum ion optics.

Soulas, George C.↗
NASA NTRS2022

Phase II and III Solid Waste Management Unit Assessment and Confirmatory Sampling Report for Per- and Polyfluorinated Alkyl Substances, Potential Release Location 237, Kennedy Space Center, Florida

Per- and polyfluoroalkyl substances (PFAS) Phase II and III Solid Waste Management Unit (SWMU) Assessment (SA) and Confirmatory Sampling (CS) were conducted at the John F. Kennedy Space Center (KSC), Potential Release Location (PRL) 237, located in Merritt Island, Brevard County, Florida for the National Aeronautics and Space Administration (NASA) under Contract 80KSC019D0010/80KSC019F0289. A Phase I SA and CS Report was previously submitted that identified 33 locations of concern (LOCs) at KSC associated with the storage, use, or release of materials containing PFAS. The objectives of the Phase II and III SA and CS were to: - Complete site and source characterization of identified LOCs; - Identify areas of potential concern (AOPCs) where past or present activities may have resulted in a release of PFAS to the environment; - Qualitatively characterize migration potential of released PFAS to environmental media (primarily soil, groundwater, surface water, and sediment); and - Identify potential receptors for exposure to PFAS-impacted environmental media. Surface water samples were collected from LOCs/AOPCs and locations on the KSC periphery during PFAS CS Phases I, II and III. Including duplicate samples, 143 environmental samples were analyzed for 14 PFAS compounds and 104 environmental samples were analyzed for 18 PFAS compounds. Ten of the analytes on the 14 compound list were detected at least once in surface water at KSC, with a wide range in magnitude of detections. The State of Florida has surface water screening levels (SWSLs) for perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in surface water, both for human and ecological receptors. The human health screening levels are lower than the ecological ones and are used in this report. PFOA was not detected in surface water at concentrations exceeding the SWSL at any LOC or Area of Potential Concern (AOPC). PFOS was detected in surface water at concentrations exceeding the SWSL at 28 LOCs/AOPCs, plus 42 locations on the KSC periphery. The data suggest a wide distribution of PFAS, particularly PFOS, in surface water but the sources of surface water contamination are not yet adequately understood. Sediment samples were collected during Phases II and III but not Phase I. Including duplicate samples, 104 environmental samples were analyzed for 14 PFAS compounds and 10 environmental samples were analyzed for 18 PFAS compounds. Twelve compounds were detected in sediment at KSC, with a wide range in magnitude of detections. There are currently no screening levels or cleanup target levels (CTLs) for sediment. The need to delineate and further characterize PFAS in sediment will be evaluated for those sites that move forward into Site Assessment. Groundwater samples were collected via DPT from LOCs/AOPCs and locations on the KSC periphery during PFAS CS Phases I, II and III. Including duplicate samples, 812 environmental DPT groundwater samples were analyzed for 14 PFAS compounds and 247 environmental samples were analyzed for 18 PFAS compounds. Twelve of the 14 compounds were detected in groundwater at KSC, with a wide range in magnitude of detections. The State of Florida has provisional groundwater cleanup target levels (GCTLs) for PFOA, PFOS and the additive concentration of PFOA+PFOS. PFOA was detected in groundwater at concentrations exceeding its provisional GCTL at 16 LOCs/AOPCs, with no exceedances on the KSC periphery. PFOS was detected in groundwater at concentrations exceeding its provisional GCTL at 30 LOCs/AOPCs, plus two locations on the KSC periphery. PFOA+PFOS was detected in groundwater at concentrations exceeding the provisional GCTL at 31 LOCs/AOPCs, plus two locations on the KSC periphery. Soil samples were collected during Phases II and III but not Phase I. Including duplicate samples, 292 environmental samples were analyzed for 14 PFAS compounds and 80 environmental samples were analyzed for 18 PFAS compounds. Fourteen compounds were detected in soil at KSC, with a wide range in magnitude of detections. The State of Florida has provisional soil cleanup target levels (SCTLs) for PFOA and PFOS. There were no PFOA results above its provisional SCTL. There was one LOC with a result above the provisional SCTL for residential settings. Recommendations are presented for each LOC and AOPC.

PFAS↗