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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Continuous Czochralski growth: Silicon sheet growth development of the large area silicon sheet task of the Low Cost Silicon Solar Array project

The primary objective of this contract is to develop equipment and methods for the economic production of single crystal ingot material by the continuous Czochralski (CZ) process. Continuous CZ is defined for the purpose of this work as the growth of at least 100 kilograms of ingot from only one melt container. During the reporting period (October, 1977 - September, 1978), a modified grower was made fully functional and several recharge runs were performed. The largest run lasted 44 hours and over 42 kg of ingot was produced. Little, if any, degradation in efficiency was observed as a result of pulling multiple crystals from one crucible. Solar efficiencies observed were between 9.3 and 10.4% AMO (13.0 and 14.6% AMI) compared to 10.5% (14.7% AMI) for optimum CZ material control samples. Using the SAMICS/IPEG format, economic analysis of continuous CZ suggests that 1986 DoE cost goals can only be met by the growth of large diameter, large mass crystals.

Source record↗
NASA NTRS2016

Elaborated Odor Test for Extended Exposure

Concerns were raised when incidental exposure to a proprietary bonding material revealed the material had an irritating odor. The NASA-STD-6001B document describes a supplemental test method option for programs to evaluate materials with odor concerns (Test 6, Odor Assessment). In addition to the supplemental standard odor assessment with less than 10 seconds of exposure, the NASA White Sands Test Facility (WSTF) Materials Flight Acceptance Testing section was requested to perform an odor test with an extended duration to evaluate effects of an extended exposure and to more closely simulate realistic exposure scenarios. With approval from the NASA Johnson Space Center Industrial Hygienist, WSTF developed a 15-minute odor test method. WSTF performed this extended-duration odor test to evaluate the odor and physical effects of the bonding material configured between two aluminum plates, after the safety of the gas was verified via toxicity analysis per NASA-STD-6001B Test 7, Determination of Offgassed Products. During extended-duration testing, odor panel members were arranged near the test material in a small room with the air handlers and doors closed to minimize dilution. The odor panel members wafted gas toward themselves and recorded their individual assessments of odor and physical effects at various intervals during the 15-minute exposure and posttest. A posttest interview was conducted to obtain further information. Testing was effective in providing data for comparison and selection of an optimal offgassing and odor containment configuration. The developed test method for extended exposure is proposed as a useful tool for further evaluating materials with identified odors of concern if continued use of the material is anticipated.

Buchanan, Vanessa D.↗
NASA NTRSDate not supplied

3D Printed Materials Characterization for Rapid Prototyping and Plant Growth

Space Biology experimentation but their effects during plant growth and sanitation have not been documented. With further testing we can determine how certain 3D printed materials affect our plants. The way we tested germination included laying two pieces of germination paper down with the printed petri dish insert of the various material and 14 seeds of Outrageous lettuce to fit in the holes of the insert. We kept an even moisture in all parts by wrapping the petri dishes in two layers of parafilm tape. This project tests over 15 different materials to document performance during plant growth scenarios. This research will not only help space biology but also citizens who use these materials to understand the potential of leaching and ill effects. 3D printing is a recent generally accessed technology with new materials coming out every day. It is important to understand how materials could impact the way the plants grow, and the safety of the food grown. As we continue testing these materials, we will also test engineering properties like tension and elasticity. We have a microbiology team working on this project as well to test biofilm formation. From the germination tests we have completed we have seen little impact on germination rate of these seeds. However, some parts absorb moisture. An ideal material is one that doesn’t leach chemicals or microplastics, can withstand high tension and compression, and doesn’t promote microbial growth. This work is funded by NASA. M. Gandhi was funded by MAIANSE.

Mily Gandhi↗
NASA NTRS1990

COMGEN: A computer program for generating finite element models of composite materials at the micro level

COMGEN (Composite Model Generator) is an interactive FORTRAN program which can be used to create a wide variety of finite element models of continuous fiber composite materials at the micro level. It quickly generates batch or session files to be submitted to the finite element pre- and postprocessor PATRAN based on a few simple user inputs such as fiber diameter and percent fiber volume fraction of the composite to be analyzed. In addition, various mesh densities, boundary conditions, and loads can be assigned easily to the models within COMGEN. PATRAN uses a session file to generate finite element models and their associated loads which can then be translated to virtually any finite element analysis code such as NASTRAN or MARC.

Melis, Matthew E.↗
NASA NTRS2021

Matrix Microcracking Effect on the Structural Response of a Thermal Protection System

The effect of microcracking in the phenolic matrix of a three-dimensional woven thermal protection system (TPS) and resulting material stiffness reduction was studied via a comparison of finite element results from linear and iterative linear analyses. A dual-layer continuous dry weave material with a low-density phenolic resin matrix has been developed for use in extreme environments. Due to high stresses in the through-the-thickness direction, microcracks may form in the matrix. The matrix does not have structural load transfer requirements, and testing has shown that microcracked phenolic resin satisfies thermal requirements. Microcracks in the matrix would result in a reduction of stiffness, which could alter the structural performance. A study was conducted to determine if reduction in material stiffness would change the load paths or structural margins. A linear finite element analysis that did not account for microcracking and an iterative linear finite element analysis that accounted for propagation microcracks were compared. Four subcases were analyzed with results indicating that the assumed propagation strength for the microcracking is the critical parameter for determining the extent of microcracking. Phenolic microcracking does not appear to have an adverse effect on the structural response and is not a critical failure for the modeled TPS.

Thermal Protection System↗
NASA NTRS1993

Generating Finite-Element Models Of Composite Materials

Program starts at micromechanical level, from simple inputs supplied by user. COMGEN, COmposite Model GENerator, is interactive FORTRAN program used to create wide variety of finite-element models of continuous-fiber composite materials at micromechanical level. Quickly generates batch or "session files" to be submitted to finite-element preprocessor and postprocessor program, PATRAN. COMGEN requires PATRAN to complete model.

Melis, M. E.↗
NASA NTRS1972

Development of a core sheath process for production of oxide fibers

Improvements were sought in an oxide fiber of a core sheath configuration intended for structural applications at 2000 F (1093 C). Discontinuities in the core were eliminated by using core materials other than pure alumina, and continuous core sheath fibers were produced. In the case of some core materials, the continuous sections were sufficiently long for applications in short fiber composites. Creep at 2000 F (1093 C) was found to be due, in most cases, to breaks in the core, allowing the glass sheath to creep. Evidence was obtained indicating that a closer match between the thermal expansion coefficient of the sheath and the core would greatly improve the strength.

Freske, S.↗
NASA NTRS2018

Chapter 8: Materials for Exploration Systems

Materials science and processing research in space can be thought of as a field of study that began with the sounding rocket experiments in the 1950s. Material science studies of the lunar surface materials returned during the Apollo missions enabled the study of lunar resource utilization. The study of materials science and processing in space continued with over 30 years of microgravity materials processing research which continues today in the International Space Station. These studies are the technical foundation that could enable lower cost human exploration through the use of in-situ propellant production, the production of energy from space resources, and the eventual establishment of a substantial portion of humanity living self sufficiently off Earth.

Curreri, Peter A.↗
NASA NTRS1992

Advanced materials for high-temperature thermoelectric energy conversion

A number of refractory semiconductors are under study at the Jet Propulsion Laboratory for application in thermal to electric energy conversion for space power. The main thrust of the program is to improve or develop materials of high figure of merit and, therefore, high conversion efficiencies over a broad temperature range. Materials currently under investigation are represented by silicon-germanium alloys, lanthanum telluride, and boron carbide. The thermoelectric properties of each of these materials, and prospects for their further improvements, are discussed. Continued progress in thermoelectric materials technology can be expected to yield reliable space power systems with double to triple the efficiency of current state of the art systems.

Vining, Cronin B.↗
NASA NTRS2003

Overview of NASA GRC Stirling Technology Development

The Stirling Radioisotope Generator (SRG) is currently being developed by Lockheed Martin Astronautics (LMA) under contract to the Depar1ment of Energy (DOE). The generator will be a high efficiency electric power source for NASA Space Science missions with the capability to operate in the vacuum of deep space or in an atmosphere such as on the surface of Mars. High system efficiency is obtained through the use of free-piston Stirling power conversion technology. Power output of the generator will be greater than 100 watts at the beginning of life with the decline in power being largely due to the decay of the plutonium heat source. In suppOl1 of the DOE SRG project, the NASA Glenn Research Center (GRC) has established a near-term technology effort to provide some of the critical data to ensure a successful transition to flight for what will be the first dynamic power system used in space. Initially, a limited number of technical areas were selected for the GRC effort, however this is now being expanded to more thoroughly cover a range of technical issues. The tasks include in-house testing of Stirling convertors and controllers, materials evaluation and heater head life assessment, structural dynamics, electromagnetic interference, organics evaluation, and reliability analysis. Most of these high-level tasks have several subtasks within. There is also an advanced technology effort that is complementary near-term technology effort. Many of the tests make use of the 55-We Technology Demonstration Convel10r (TDC). There have been multiple controller tests to support the LMA flight controller design effort. Preparation is continuing for a thermal/vacuum system demonstration. A pair of flight prototype TDC's have recently been placed on an extended test with unattended, continuous operation. Heater head life assessment efforts continue, with the material data being refined and the analysis moving toward the system perspective. Long-term magnet aging tests are continuing to characterize any possible aging in the strength or demagnetization resistance of the permanent magnets used in the linear alternator. In a parallel effort, higher performance magnets are also being evaluated. A reliability effort is being initiated that will help to guide the development activities with an increased focus on the necessary components and subsystems. Some other disciplines that are active in the GRC technology effort include structural dynamics, linear alternator analysis, EMI/EMC, controls, and mechanical design evaluation. This paper will provide an overview of some of the GRC technical efforts, including the current status, and a description of future efforts.

Schreiber, Jeffrey↗
NASA NTRS2014

In-Situ Wire Damage Detection System

An in-situ system for detecting damage in an electrically conductive wire. The system includes a substrate at least partially covered by a layer of electrically conductive material forming a continuous or non-continuous electrically conductive layer connected to an electrical signal generator adapted to delivering electrical signals to the electrically conductive layer. Data is received and processed to identify damage to the substrate or electrically conductive layer. The electrically conductive material may include metalized carbon fibers, a thin metal coating, a conductive polymer, carbon nanotubes, metal nanoparticles or a combination thereof.

Williams, Martha K.↗
NASA NTRS1990

Analytical solutions with Generalized Impedance Boundary Conditions (GIBC)

The diffraction by a material discontinuity in a thick dielectric/ferrite layer is considered by modeling the layer as a distributed current sheet obeying generalized sheet transition conditions (GSTC's). The sheet currents are then formulated and solved via the standard dual integral equation approach. This yields the diffracted field in terms of unknown constants which underscore the non-uniqueness of the GSTC current sheet representation. The constants are dependent on the geometry and properties of the discontinuity and are determined by enforcing field continuity across the material junction. This requires the field internal to the slab which are determined from the external ones via analytic continuity. Results are given which validate the solution and demonstrate the importance of the constants.

Ricoy, Mark A.↗
NASA NTRSDate not supplied

Continuation of Solar Absorptivity Degradation of Spacecraft Materials Due to UV and Charged Particles in the Gateway Environment

Gateway is a lunar orbiting platform that will be assembled in space similar to the International Space Station. Modules will arrive following different transit orbits, some of which have an extended duration in the Van Allen Belts. This means the spacecraft is exposed to significant charged particle radiation, after which it must operate in cislunar space for 15 years. Charged particle and UV degradation of potential Gateway materials was identified as a knowledge gap by the Passive Thermal Control System (PTCS) Group as end-of-life solar absorptivity greatly impacts thermal performance. Multiple rounds of ground testing have been completed at NASA Goddard Space Flight Center in which potential Gateway materials were subjected to expected worst-case transit charged particle fluence (9.86x1015 protons/cm2 at 2.5 keV and 3.1x1016 electrons/cm2 at 10 keV) and up to 5093 Equivalent Solar Hours (ESH) of UV exposure. This report builds on previous data from Zinecker et al. 2022 which presented the first round of ground testing. Additional materials have been tested and solar absorptivity degradation along with lessons learned are shared. Comparisons to previous results are also presented.

Brandon Hoffmann↗
NASA NTRS2024

Continuation of Solar Absorptivity Degradation of Spacecraft Materials Due to UV and Charged Particles in the Gateway Environment

Gateway is a lunar orbiting platform that will be assembled in space similar to the International Space Station. Modules will arrive following different transit orbits, some of which have an extended duration in the Van Allen Belts. This means the spacecraft is exposed to significant charged particle radiation, after which it must operate in cislunar space for 15 years. Charged particle and UV degradation of potential Gateway materials was identified as a knowledge gap by the Passive Thermal Control System (PTCS) Group as end-of-life solar absorptivity greatly impacts thermal performance. Multiple rounds of ground testing have been completed at NASA Goddard Space Flight Center in which potential Gateway materials were subjected to expected worst-case transit charged particle fluence (9.86 x 10 15 protons/cm 2 at 2.5 keV and 3.1x10 16 electrons/cm 2 at 10 keV) and up to 5093 Equivalent Solar Hours (ESH) of UV exposure. This report builds on previous data from Zinecker et al. 2022. Round 1a was published in that paper and Rounds 2a, 2b, and 2c are discussed here with some comparisons to Round 1a. Additional materials have been tested and solar absorptivity degradation is presented along with comparisons to previous results.

Brandon Hoffmann↗
NASA NTRS2012

Electrospun Nanofiber Coating of Fiber Materials: A Composite Toughening Approach

Textile-based composites could significantly benefit from local toughening using nanofiber coatings. Nanofibers, thermoplastic or otherwise, can be applied to the surface of the fiber tow bundle, achieving toughening of the fiber tow contact surfaces, resulting in tougher and more damage-resistant/tolerant composite structures. The same technique could also be applied to other technologies such as tape laying, fiber placement, or filament winding operations. Other modifications to the composite properties such as thermal and electrical conductivity could be made through selection of appropriate nanofiber material. Control of the needle electric potential, precursor solution, ambient temperature, ambient humidity, airflow, etc., are used to vary the diameter and nanofiber coating morphology as needed. This method produces a product with a toughening agent applied to the fiber tow or other continuous composite precursor material where it is needed (at interfaces and boundaries) without interfering with other composite processing characteristics.

Kohlman, Lee W.↗
NASA NTRS1989

The role of cometary particle coalescence in chemical evolution

Important prebiotic organic compounds might have been transported to earth in dust or produced in vapor clouds resulting from atmospheric explosions or impacts of comets. These compounds coalesced in the upper atmosphere with particles ejected from craters formed by impacts of large objects. Coalescence during exposure to UV radiation concentrated organic monomers and enhanced formation of oligomers. Continuing coalescence added material to the growing particles and shielded prebiotic compounds from prolonged UV radiation. These particles settled into the lower atmosphere where they were scavenged by rain. Aqueous chemistry and evaporation of raindrops containing monomers in high temperature regions near the earth's surface also promoted continued formation of oligomers. Finally, these oligomers were deposited in the oceans where continued prebiotic evolution led to the most primitive cell. Results of present studies suggest that prebiotic chemical evolution may be an inevitable consequence of impacting comets during the late accretion of planets anywhere in the universe if oceans remained on those planetary surfaces.

Oberbeck, V. R.↗
NASA NTRS1980

Heatshield material selection for advanced ballistic reentry vehicles

The Performance of staple rayon fiber and AVTEX continuous rayon fiber was evaluated as precursor materials for heatshields. The materials studied were referenced to the IRC FM5055A heatshield materials flown during the past decade. Three different arc jet facilities were used to simulate portions of the reentry environment. The IRC FM5055A and the AVTEX FM5055G, both continuous rayon fiber woven materials having the phenolic impregnant filled with carbon particles were compared. The AVTEX continuous fiber, unfilled material FM5822A was also examined to a limited extent. Test results show that the AVTEX FM5055G material provided a close substitute for the IRC FM5055A material both in terms of thermal protection and roll torque performance.

Legendre, P. J.↗
NASA NTRS2010

Propulsion Design With Freeform Fabrication (PDFF)

The nation is challenged to decrease the cost and schedule to develop new space transportation propulsion systems for commercial, scientific, and military purposes. Better design criteria and manufacturing techniques for small thrusters are needed to meet current applications in missile defense, space, and satellite propulsion. The requirements of these systems present size, performance, and environmental demands on these thrusters that have posed significant challenges to the current designers and manufacturers. Designers are limited by manufacturing processes, which are complex, costly, and time consuming, and ultimately limited in their capabilities. The PDFF innovation vastly extends the design opportunities of rocket engine components and systems by making use of the unique manufacturing freedom of solid freeform rapid prototype manufacturing technology combined with the benefits of ceramic materials. The unique features of PDFF are developing and implementing a design methodology that uses solid freeform fabrication (SFF) techniques to make propulsion components with significantly improved performance, thermal management, power density, and stability, while reducing development and production costs. PDFF extends the design process envelope beyond conventional constraints by leveraging the key feature of the SFF technique with the capability to form objects with nearly any geometric complexity without the need for elaborate machine setup. The marriage of SFF technology to propulsion components allows an evolution of design practice to harmonize material properties with functional design efficiency. Reduced density of materials when coupled with the capability to honeycomb structure used in the injector will have significant impact on overall mass reduction. Typical thrusters in use for attitude control have 60 90 percent of its mass in the valve and injector, which is typically made from titanium. The combination of material and structure envisioned for use in an SFF thruster design could reduce thruster weight by a factor of two or more. The thrust-to-weight ratios for such designs can achieve 1,000:1 or more, depending on chamber pressure. The potential exists for continued development in materials, size, speed, accuracy of SFF techniques, which can lead to speculative developments of PDFF processes such as fabrication of custom human interface devices like masks, chairs, and clothing, and advanced biomedical application to human organ reconstruction. Other potential applications are: higher fidelity lower cost test fixtures for probes and inspection, disposable thrusters, and ISRU (in situ resource utilization) for component production in space or on Lunar and Martian missions, and application for embedding MEMS (microelectromechanical systems) during construction process of form changing aerostructure/dynamic structures.

Barnes, Daudi↗