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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 937 records · Page 52

All sources NASA NTRS DOE OSTI

NASA NTRS2010

Modeling the Space Debris Environment with MASTER-2009 and ORDEM2010

Spacecraft analysis using ORDEM2010 uses a high-fidelity population model to compute risk to on-orbit assets. The ORDEM2010 GUI allows visualization of spacecraft flux in 2-D and 1-D. The population was produced using a Bayesian statistical approach with measured and modeled environment data. Validation of sizes < 1mm were performed using Shuttle window and radiator impact measurements. Validation of sizes > 1mm is on-going.

Flegel, S.↗

DOE OSTI2020

Self-powered and reversible light-directed electrophoretic deposition device for use in smart windows and photodetector displays

According to one embodiment, a method includes receiving light on a photoconductive layer of an electrophoretic deposition (EPD) device, the EPD device having a chamber defined by a first sheet, a second sheet and a spacer between the first and second sheets, where the first sheet is nonopaque and includes the photoconductive layer, where the second sheet is nonopaque and spaced from the first sheet, where a fluidic solution having a plurality of particles is in the chamber. The particles in the solution are attracted from suspension to illuminated portions of the photoconductive layer in the absence of an external voltage applied to the first and second sheets. The particles become deposited on the illuminated portions of the photoconductive layer.

42 ENGINEERING↗

DOE OSTI2022

BOSS DR12 full-shape cosmology: Λ CDM constraints from the large-scale galaxy power spectrum and bispectrum monopole

Here, we present a full Λ CDM analysis of the BOSS DR12 dataset, including information from the power spectrum multipoles, the real-space power spectrum, the reconstructed power spectrum and the bispectrum monopole. This is the first analysis to feature a complete treatment of the galaxy bispectrum, including a consistent theoretical model and without large-scale cuts. Unlike previous works, the statistics are measured using window-free estimators: this greatly reduces computational costs by removing the need to window-convolve the theory model. Our pipeline is tested using a suite of high-resolution mocks and shown to be robust and precise, with systematic errors far below the statistical thresholds. Inclusion of the bispectrum yields consistent parameter constraints and shrinks the σ 8 posterior by 13% to reach < 5 % precision; less conservative analysis choices would reduce the error bars further. Our constraints are broadly consistent with Planck: in particular, we find H 0 = 69.6$^{+1.1}_{–1.3}$ km s –1 Mpc –1 , σ 8 = 0.692$^{+0.035}_{–0.041}$ and n s = 0.870$^{+0.067}_{–0.064}$, including a BBN prior on the baryon density. When n s is set by Planck, we find H 0 = 68.31$^{+0.83}_{–0.86}$ km s –1 Mpc –1 and σ 8 = 0.722$^{+0.032}_{–0.036}$. Our S 8 posterior, 0.751 ± 0.039, is consistent with weak lensing studies, but lower than Planck. Constraints on the higher-order bias parameters are significantly strengthened from the inclusion of the bispectrum, and we find no evidence for deviation from the dark matter halo bias relations. These results represent the most complete full-shape analysis of BOSS DR12 to-date, and the corresponding spectra will enable a variety of beyond-Λ CDM analyses, probing phenomena such as the neutrino mass and primordial non-Gaussianity.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2021

The Instrument of the Imaging X-Ray Polarimetry Explorer

While X-ray spectroscopy, timing, and imaging have improved much since 1962 when the first astronomical nonsolar source was discovered, especially wi the launch of the Newton/X-ray Multi-Mirror Mission, Rossi/X-ray Timing Explorer, and Chandra/Advanced X-ray Astrophysics Facility, the progress of X-ray polarimetry has been meager. This is in part due to the lack of sensitive polarization detectors, which in turn is a result of the fate of approved missions and because celestial X-ray sources appear less polarized than expected. Only one positive measurement has been available until now: the Orbiting Solar Observatory measured the polarization of the Crab Nebula in the 1970s. The advent of microelectronics techniques has allowed for designing a detector based on the photoelectric effect of gas in an energy range where the optics are efficient at focusing in X-rays. Here we describe the instrument, which is the major contribution of the Italian collaboration to the Small Explorer mission called IXPE, the Imaging X-ray Polarimetry Explorer, which will launch in late 2021. The instrument is composed of three detector units based on this technique and a detector service unit. Three mirror modules provided by Marshall Space Flight Center focus X-rays onto the detectors. We show the technological choices, their scientific motivation, and results from the calibration of the instrument. IXPE will perform imaging, timing, and energy-resolved polarimetry in the 2–8 keV energy band opening this window of X-ray astronomy to tens of celestial sources of almost all classes.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS1999

Mission Planning for the CHANDRA X-Ray Observatory

The CHANDRA x-ray observatory started life as the Advanced X-ray Facility (AXAF) but was renamed Chandra in December of 1998 at the of a nationwide contest by NASA to name the new observatory. The honors the Nobel Prize winning astrophysicist S. Chandrasekar who astrophysics at the University of Chicago for more than 50 years, following graduate studies at Cambridge University in England. The observatory has been under construction for a decade under the management of the Observatory observatory, Projects office at the Marshall Space Flight Center; the same office that oversaw the construction of the Hubble Space Telescope and the Compton Gamma Ray Observatory. This observatory is a member of NASA's great observatory series of missions of which Hubble and Compton are members. This paper describes the mission planning that was conducted at MSFC to design the orbit and launch window that would permit the new observatory to function properly.

Mullins, Larry D.↗

NASA NTRS1993

High Tech Art: Chameleon Glass

Dichroic Glass is a technology wherein extremely thin films of metal are vacuum deposited on a glass surface. The coated glass shields spacecraft instruments from cosmic radiation and protects human vision from unfiltered sunlight in space. Because the coating process allows some wavelengths of light and color to reflect and others to pass through, a chameleon effect is produced. Murray Schwartz, a former aerospace engineer, has based his business KROMA on this NASA optical technology. He produces dichroic stained glass windows, mobiles and jewelry. The technique involves deposition of super thin layers of metal oxides applied one layer at a time in a specific order and thickness for the desired effect. His product line is unique and has been very successful.

Source record↗

NASA NTRSDate not supplied

Dragonfly mass spectrometer titan environment optical damage testing

The Dragonfly Mass Spectrometer (DraMS) being developed at NASA’s Goddard Space Flight Center will use a solid-state 266-nm pulsed Nd:YAG laser perform compositional analysis on the surface of Titan. Due to the high fluence of the focused pulse energy on the laser’s beam steering unit (BSU) and the mass spectrometer window, the damage threshold of these optics in a Titan atmosphere needed to be characterized. This paper details the test setup and the successful demonstration of testing the highest fluence optics for the expected mission duration of 2 million laser pulses in a Titan-relevant atmosphere.

Matt Mullin↗

NASA NTRS1999

Self-organizing map (SOM) of space acceleration measurement system (SAMS) data

In this paper, space acceleration measurement system (SAMS) data have been classified using self-organizing map (SOM) networks without any supervision; i.e., no a priori knowledge is assumed regarding input patterns belonging to a certain class. Input patterns are created on the basis of power spectral densities of SAMS data. Results for SAMS data from STS-50 and STS-57 missions are presented. Following issues are discussed in details: impact of number of neurons, global ordering of SOM weight vectors, effectiveness of a SOM in data classification, and effects of shifting time windows in the generation of input patterns. The concept of 'cascade of SOM networks' is also developed and tested. It has been found that a SOM network can successfully classify SAMS data obtained during STS-50 and STS-57 missions.

STS-57 Shuttle Project↗

NASA NTRS2002

Facility and Methods Developed for Simulated Space Vacuum Ultraviolet Exposure Testing of Polymer Films

Vacuum ultraviolet (VUV) radiation of wavelengths between 115 and 200 nm produced by the Sun in the space environment can degrade polymer films, producing changes in their optical, mechanical, and chemical properties. These effects are particularly important for thin polymer films being considered for ultralightweight space structures, because, for most polymers, VUV radiation is absorbed in a thin surface layer. The NASA Glenn Research Center has developed facilities and methods for long-term ground testing of polymer films to evaluate space environmental VUV radiation effects. VUV exposure can also be used as part of combined or sequential simulated space environmental exposures to determine combined damaging effects with other aspects of the space environment, which include solar ultraviolet radiation, solar flare x-rays, electron and proton radiation, atomic oxygen (for low-Earth-orbit missions), and temperature effects. Because the wavelength sensitivity of VUV damage is not well known for most materials, Glenn's VUV facility uses a broad-spectrum deuterium lamp with a magnesium fluoride window that provides output between 115 and 200 nm. Deuterium lamps of this type were characterized by the National Institute of Standards and Technology and through measurements at Glenn. Spectral irradiance measurements show that from approximately 115 to 160 nm, deuterium lamp irradiance can be many times that of air mass zero solar irradiance, and as wavelength increases above approximately 160 nm, deuterium lamp irradiance decreases in comparison to the Sun. The facility is a cryopumped vacuum chamber that achieves a system pressure of approximately 5310(exp -6) torr. It contains four individual VUV-exposure compartments in vacuum, separated by water-cooled copper walls to minimize VUV radiation and any sample contamination cross interactions between compartments. Each VUV-exposure compartment contains a VUV deuterium lamp, a motor-controlled sample stage coupled with a moveable cesium iodide VUV phototube, and two thermocouples for temperature measurement. The vacuum chamber and exterior equipment is shown. Each VUV lamp is located at the top of the chamber with its projection-tube pushed through an O-ring compression fitting. The lamp assemblies are located on ports that can be isolated from the rest of the vacuum chamber, permitting maintenance or replacement of the lamps without breaking vacuum in the main chamber where the samples are located. A view of two of the four interior VUV-exposure compartments, including the moveable sample stages and detector holders is also shown. Glenn is using this facility to support testing of Next Generation Space Telescope sunshield materials that is being led by the NASA Goddard Space Flight Center and to develop an understanding of the wavelength, intensity, and temperature dependence of VUV-induced polymer degradation.

Dever, Joyce A.↗

DOE OSTI2017

Structural and chemical evolution of the CdS:O window layer during individual CdTe solar cell processing steps

Oxygenated cadmium sulfide (CdS:O) is often used as the n-type window layer in high-performance CdTe heterojunction solar cells. The as-deposited layer prepared by reactive sputtering is XRD amorphous, with a bulk composition of CdS0.8O1.2. Recently it was shown that this layer undergoes significant transformation during device fabrication, but the roles of the individual high temperature processing steps was unclear. In this work high resolution transmission electron microscopy coupled to elemental analysis was used to understand the evolution of the heterojunction region through the individual high temperature fabrication steps of CdTe deposition, CdCl2 activation, and back contact activation. It is found that during CdTe deposition by close spaced sublimation at 600 degrees C the CdS:O film undergoes recrystallization, accompanied by a significant (~30%) reduction in thickness. It is observed that oxygen segregates during this step, forming a bi-layer morphology consisting of nanocrystalline CdS adjacent to the tin oxide contact and an oxygen-rich layer adjacent to the CdTe absorber. This bilayer structure is then lost during the 400 degrees C CdCl2 treatment where the film transforms into a heterogeneous structure with cadmium sulfate clusters distributed randomly throughout the window layer. The thickness of window layer remains essentially unchanged after CdCl2 treatment, but a ~25 nm graded interfacial layer between CdTe and the window region is formed. Finally, the rapid thermal processing step used to activate the back contact was found to have a negligible impact on the structure or composition of the heterojunction region.

14 SOLAR ENERGY↗

DOE OSTI2023

Resonant dynamics of one-side multipactor on dielectric

Breakdown of dielectric radio frequency (RF) windows is an important issue for particle accelerators and high-power RF sources. One of the common reasons for RF window failure is the multipactor on a dielectric surface. The multipactor may be responsible for excessive heating of the dielectric and discharge of charges that accumulated in the ceramic due to secondary emission. In this study, comprehensive self-consistent particle-in-cell simulations with space charge effect were performed. This was to better understand the dynamic of one-side multipactor development and floating potential on the dielectric induced by the emission. The important correlations between the multipactor parameters at saturation, the secondary emission properties of dielectric, and the applied RF field parameters have been found, which led to the conclusion that the dynamics of one-side multipactor on dielectric is a resonant phenomenon.

43 PARTICLE ACCELERATORS↗

DOE OSTI2022

Hydrogen-powered Electrochemically-driven CO 2 Removal from Air Containing 400 to 5000 ppm CO 2

The performance of a hydrogen-powered, electrochemically-driven CO 2 separator (EDCS) was demonstrated at cathode inlet CO 2 concentrations from 400 ppm to 5,000 ppm. The impact of current density and CO 2 concentration were evaluated to predict operating windows for various applications. The single-cell data was used to scale a 100 cm 2 , multi-cell stack using a shorted-membrane design for four applications: direct air capture (DAC), hydroxide exchange membrane fuel cell (HEMFC) air pretreatment, submarine life support, and space habitation. For DAC, a 339-cell EDCS stack (7.7 L, 17 kg) was projected to remove 1 tonne CO 2 per year. The addition of the EDCS in HEMFC systems would result in nearly a 30% increase in volume, and therefore further improvements in performance would be necessary. A module containing five 338-cell EDCS stacks (38 L, 85 kg) in parallel can support a 150 person crew at 2.1% of the volume of the liquid amine system employed in submarines. For space habitation, a 109-cell EDCS stack (3.2 L, 10 kg) is adequate for 6 crewmembers, and is less than 1% the size and 5% the weight of the current CO 2 removal system installed on the International Space Station.

25 ENERGY STORAGE↗

NASA NTRS1971

Experiment T002: Manual navigation sightings

Navigation-type measurements through the window of the stabilized Gemini 12 spacecraft by the use of a hand-held sextant are reported. The major objectives were as follows: (1) to evaluate the ability of the crewmen to make accurate navigational measurements by the use of simple instruments in an authentic space flight environment; (2) to evaluate the operational feasibility of the measurement techniques by the use of the pressure suit with the helmet off and with the helmet on and the visor closed; (3) to evaluate operational problems associated with the spacecraft environment; and (4) to validate ground based simulation techniques by comparison of the inflight results with base line data obtained by the pilot by the use of simulators and celestial targets from ground based observatories.

Smith, D.↗

NASA NTRS2004

Effects of Various Wavelength Ranges of Vacuum Ultraviolet Radiation on Teflon FEP Film Investigated

Teflon Fluorinated Ethylene Propylene (FTP) films (DuPont) have been widely used for spacecraft thermal control and have been observed to become embrittled and cracked upon exposure to the space environment. This degradation has been attributed to a synergistic combination of radiation and thermal effects. A research study was undertaken at the NASA Glenn Research Center to examine the effects of different wavelength ranges of vacuum ultraviolet (VUV) radiation on the degradation of the mechanical properties of FEP. This will contribute to an overall understanding of space radiation effects on Teflon FEP, and will provide information necessary to determine appropriate techniques for using laboratory tests to estimate space VUV degradation. Research was conducted using inhouse facilities at Glenn and was carried out, in part, through a grant with the Cleveland State University. Samples of Teflon FEP film of 50.8 microns thickness were exposed to radiation from a VUV lamp from beneath different cover windows to provide different exposure wavelength ranges: MgF2 (115 to 400 nm), crystalline quartz (140 to 400 nm), and fused silica (FS, 155 to 400 nm). Following exposure, FEP film specimens were tensile tested to determine the ultimate tensile strength and elongation at failure as a function of the exposure duration for each wavelength range. The graphs show the effect of ultraviolet exposure on the mechanical properties of the FEP samples.

Dever, Joyce A.↗

NASA NTRS2013

Basic Operational Robotics Instructional System

The Basic Operational Robotics Instructional System (BORIS) is a six-degree-of-freedom rotational robotic manipulator system simulation used for training of fundamental robotics concepts, with in-line shoulder, offset elbow, and offset wrist. BORIS is used to provide generic robotics training to aerospace professionals including flight crews, flight controllers, and robotics instructors. It uses forward kinematic and inverse kinematic algorithms to simulate joint and end-effector motion, combined with a multibody dynamics model, moving-object contact model, and X-Windows based graphical user interfaces, coordinated in the Trick Simulation modeling environment. The motivation for development of BORIS was the need for a generic system for basic robotics training. Before BORIS, introductory robotics training was done with either the SRMS (Shuttle Remote Manipulator System) or SSRMS (Space Station Remote Manipulator System) simulations. The unique construction of each of these systems required some specialized training that distracted students from the ideas and goals of the basic robotics instruction.

Todd, Brian Keith↗

NASA NTRS2019

Detecting Layer Height of Smoke Aerosols over Vegetated Land and Water Surfaces via Oxygen Absorption Bands: Hourly Results from EPIC/DSCOVR in Deep Space

We present an algorithm for retrieving aerosol layer height (ALH) and aerosol optical depth (AOD) for smoke over vegetated land and water surfaces from measurements of the Earth Polychromatic Imaging Camera (EPIC) onboard the Deep Space Climate Observatory (DSCOVR). The algorithm uses Earth-reflected radiances in six EPIC bands in the visible and near-infrared and incorporates flexible spectral fitting that accounts for specifics of land and water surface reflectivity. The fitting procedure first determines AOD using EPIC atmospheric window bands (443 nm, 551 nm, 680nm, and 780 nm), then uses oxygen (O2) A and B bands (688 nm and 764 nm) to derive ALH, which represents an optical centroid altitude. ALH retrieval over vegetated surface primarily takes advantage of measurements in the O2B band. We applied the algorithm to EPIC observations of several biomass burning events over the United States and Canada in August 2017. We found that the algorithm can be used to obtain AOD and ALH multiple times daily over water and vegetated land surface. Validation is performed against aerosol extinction profiles detected by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and against AOD observed at nine Aerosol Robotic Network (AERONET) sites, showing, on average, an error of 0.58 km and a bias of -0.13 km in retrieved ALH and an error of 0.05 and a bias of 0.03 in retrieved AOD. Additionally, we show that the aerosol height information retrieved by the present algorithm can potentially benefit the retrieval of aerosol properties from EPIC’s ultraviolet (UV) bands.

Cloud–Aerosol Lidar with Orthogonal Polarization (↗

NASA NTRSDate not supplied

Damage Threshold Testing of UV Optics Under a Titan Environment for NASA’s Dragonfly Mission

The Dragonfly Mass Spectrometer (DraMS) being developed at NASA’s Goddard Space Flight Center will use a solid-state 266-nm pulsed Nd:YAG laser to perform compositional analysis on the surface of Titan. Due to the high fluence of the focused pulse energy on the laser’s beam steering unit (BSU) and the mass spectrometer window, the damage threshold of these optics in a Titan atmosphere needed to be characterized. This paper details the test setup and the successful demonstration of testing the highest fluence optics for the expected mission duration of 2 million laser pulses in a Titan-relevant atmosphere.

Paul R Stysley↗

DOE OSTI2026

Preparing large area of thermochromic nanocomposite films for smart window application

The challenges posed by high building energy bill necessitate proactive implementation of energy-efficient strategies to minimize the uses of both electricity and heating gas and promote the use of free solar energy sources. "Smart" window films/glass, leveraging thermochromic vanadium dioxide (VO 2 ), offer an adaptive approach to harness solar energy, significantly reducing the thermal load of buildings. This is achieved by reflecting the infrared portion of the solar spectrum through a phase transition in the monoclinic M-phase (M) of VO 2 induced by heating. In this study, a scalable continuous flow synthesis process invented by Argonne was employed to explore a wide parameter space, targeting the controlled synthesis of monoclinic VO 2 (M) nanoparticles with well-controlled sizes and morphologies. Additionally, a doping strategy and surface modifications were utilized for high-throughput tuning of the metal-to-insulator transition temperature. Strategies to enhance the solar modulation properties of VO 2 nanoparticles in polymer films were investigated through (i) morphological transformation from spherical to nanorod structures, (ii) surface modification with low refractive index ligands, and (iii) incorporation of additional thermochromic materials for improved solar energy modulation and aesthetically appealing colors in smart films. Furthermore, the study outlines scaling-up synthesis methods for VO 2 nanoparticles in a continuous flow reactor using hydrazine monohydrate. This comprehensive investigation provides valuable insights into the upscaling synthesis and design of advanced VO 2 /polymer composite smart window films with enhanced functionality, solar energy modulation and visible light transmittance, driving the technology a step close for industrial application.

14 SOLAR ENERGY↗