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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS2012

Cases for Additive Manufacturing on the International Space Station

There are thousands of plastic or non-structural metal components on the International Space Station (ISS), any of which could require replacing sometime between resupply missions. While these may not be life critical, it can cause significant delays to flight projects that have to wait several weeks to months to receive a key part one that could have been designed and built on-board the ISS within a few hours. A plastic deposition additive manufacturing process is a low-energy, low-mass solution to many common needs on board the ISS.

Cooper, Kenneth G.↗
NASA NTRS2012

Spark-integrated propellant injector head with flashback barrier

High performance propellants flow through specialized mechanical hardware that allows for effective and safe thermal decomposition and/or combustion of the propellants. By integrating a sintered metal component between a propellant feed source and the combustion chamber, an effective and reliable fuel injector head may be implemented. Additionally the fuel injector head design integrates a spark ignition mechanism that withstands extremely hot running conditions without noticeable spark mechanism degradation.

Mungas, Gregory Stuart↗
NASA NTRS2012

Dynamically variable spot size laser system

A Dynamically Variable Spot Size (DVSS) laser system for bonding metal components includes an elongated housing containing a light entry aperture coupled to a laser beam transmission cable and a light exit aperture. A plurality of lenses contained within the housing focus a laser beam from the light entry aperture through the light exit aperture. The lenses may be dynamically adjusted to vary the spot size of the laser. A plurality of interoperable safety devices, including a manually depressible interlock switch, an internal proximity sensor, a remotely operated potentiometer, a remotely activated toggle and a power supply interlock, prevent activation of the laser and DVSS laser system if each safety device does not provide a closed circuit. The remotely operated potentiometer also provides continuous variability in laser energy output.

Gradl, Paul R.↗
NASA NTRS2012

A Multifunctional Smart Coating for Autonomous Corrosion Control

Corrosion is a destructive process that often causes failure in metallic components and structures. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to control it. The multi-functionality of the coating is based on micro-encapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of other existing microcapsules designs, the corrosion controlled release function that allows the delivery of corrosion indicators and inhibitors on demand only when and where needed. Corrosion indicators as well as corrosion inhibitors have been incorporated into microcapsules, blended into several paint systems, and tested for corrosion detection and protection efficacy. This

Calle, Luz Marina↗
NASA NTRS2013

Luminescence-Based Diagnostics of Thermal Barrier Coating Health and Performance

Thermal barrier coatings (TBCs) are typically composed of translucent ceramic oxides that provide thermal protection for metallic components exposed to high-temperature environments in both air- and land-based turbine engines. For advanced turbine engines designed for higher temperature operation, a diagnostic capability for the health and performance of TBCs will be essential to indicate when a mitigating action needs to be taken before premature TBC failure threatens engine performance or safety. In particular, it is shown that rare-earth-doped luminescent sublayers can be integrated into the TBC structure to produce luminescence emission that can be monitored to assess TBC erosion and delamination progression, and to map surface and subsurface temperatures as a measure of TBC performance. The design and implementation of these TBCs with integrated luminescent sublayers are presented.

Eldridge, Jeffrey I.↗
NASA NTRS2009

Optical Diagnostics for High-Temperature Thermal Barrier Coatings

Thermal barrier coatings (TBCs) are typically composed of translucent ceramic oxides that provide thermal protection for metallic components exposed to high-temperature environments, such as in jet turbine engines. Taking advantage of the translucent nature of TBCs, optical diagnostics have been developed that can provide an informed assessment of TBC health that will allow mitigating action to be taken before TBC degradation threatens performance or safety. In particular, rare-earth-doped luminescent sublayers have been integrated into the TBC structure to produce luminescence that monitors TBC erosion, delamination, and temperature gradients. Erosion monitoring of TBC-coated specimens is demonstrated by utilizing visible luminescence that is excited from a sublayer that is exposed by erosion. TBC delamination monitoring is achieved in TBCs with a base rare-earth-doped luminescent sublayer by the reflectance-enhanced increase in luminescence produced in regions containing buried delamination cracks. TBC temperature monitoring is demonstrated using the temperature-dependent decay time for luminescence originating from the specific coating depth associated with a rare-earth-doped luminescent sublayer. The design and implementation of these TBCs with integrated luminescent sublayers is discussed, including co-doping strategies to produce more penetrating near-infrared luminescence. It is demonstrated that integration of the rare-earth-doped sublayers is achieved with no reduction in TBC life. In addition, results for multilayer TBCs designed to also perform as radiation barriers are also presented.

Eldridge, Jeffrey I.↗
NASA NTRS2014

Multilayer Thermal Barrier Coating (TBC) Architectures Utilizing Rare Earth Doped YSZ and Rare Earth Pyrochlores

To allow for increased gas turbine efficiencies, new insulating thermal barrier coatings (TBCs) must be developed to protect the underlying metallic components from higher operating temperatures. This work focused on using rare earth doped (Yb and Gd) yttria stabilized zirconia (t' Low-k) and Gd2Zr2O7 pyrochlores (GZO) combined with novel nanolayered and thick layered microstructures to enable operation beyond the 1200 C stability limit of current 7 wt% yttria stabilized zirconia (7YSZ) coatings. It was observed that the layered system can reduce the thermal conductivity by approximately 45 percent with respect to YSZ after 20 hr of testing at 1316 C. The erosion rate of GZO is shown to be an order to magnitude higher than YSZ and t' Low-k, but this can be reduced by almost 57 percent when utilizing a nanolayered structure. Lastly, the thermal instability of the layered system is investigated and thought is given to optimization of layer thickness.

Thermal Barrier Coating↗
NASA NTRS2018

Additive Manufacturing of Liquid Rocket Engine Combustion Devices: A Summary of Process Developments and Hot-Fire Testing Results

Additive Manufacturing (AM) is an emerging technology with a focus on complex metallic component fabrication: Enables complex shapes and internal features that were not possibly with traditional manufacturing techniques, and significant schedule and overall lifecycle cost reductions. To date at the NASA Marshall Space Flight Center (MSFC), combustion devices component hardware ranging in size from 100 - 35,000 lbf has been designed and manufactured using AM and many of these pieces have been hot-fire tested.

Gradl, Paul↗
NASA NTRS2019

Stress Corrosion Evaluation of Elgiloy Alloy for the ISS ECLSS — Universal Waste Management System

Elgiloy® alloy (UNS R30003)—a spring material per AMS 5876D (reference 1)—is one among several alloys recently evaluated for stress corrosion cracking resistance in support of the International Space Station (ISS) Environmental Control and Life Support System (ECLSS). Elgiloy was evaluated particularly for its expected use in the Universal Waste Management System (described in references 2 and 3). Data for other alloys previously evaluated were reported in references 4 and 5. Materials included in reference 4 are Inconel 625, Hastelloy® C276, commercially pure titanium, titanium with 6% aluminum and 4% vanadium (Ti6Al4V), extra-low interstitial Ti6Al4V, and Cronidur 30. The results for Nitinol 60 are in reference 5. During the water recovery process, the metallic components fabricated from these materials are exposed to acidic solutions used for waste treatment. The purpose of the current and previous stress corrosion evaluations is to determine if these materials have adequate stress corrosion resistance.

Torres, Pablo D.↗
NASA NTRSDate not supplied

IIAB IRON METEORITES: FORMATION AND RELATION TO OTHER METEORITE GROUPS.

The IIAB iron meteorites are one of the largest iron meteorite groups that formed by fractional crystallization [1]. Iron meteorites formed over a range of oxygen fugacities (fO2)[2], most formed relatively reduced at~ IW–4to –2.5 (IABs), where IW= iron-wüstite buffer, to relatively oxidized at IW–1(IVBs) [2,3]. While the IIABs contain reduced mineral phases (daubré elite [1]),the fO2for IIABs is poorly constrained. The fO2of iron meteorites may have become more reducing during cooling, with oxidized phases (i.e., chromite) forming at higher temperatures and daubré elite forming at lower temperatures [4]. The O-and Cr-isotope compositions of silicates and chromite in meteorites, including iron meteorites, can determine potential genetic links to other meteorite sand con-strain if a meteorite is from the non-carbonaceous (NC) or carbonaceous (CC) group [e.g., 5–8]. Iron meteorite groups have been identified as being in the NCor CC group using Mo[9]and Ni [10] isotope compositions of their metallic component. Numerous iron meteorites contain minor amounts of silicates and oxides [e.g., 11], but most have not been analyzed for their Cr or Ti isotope compositions, with some exceptions (e.g., IIIABs [6,7],a IIG, and a IIAB[7]). We analyzed the compositions of silicates and chromite in six IIAB iron meteorites to investigate the relationship between IIABs and known meteorite groups, the fO2of IIABs, and the origin of chromite in the IIABs. *full abstract in document

Meteorite↗
NASA NTRSDate not supplied

NASA NDE Fracture Critical Detectable Flaw Sizes History and Methodology

NASA requires that NDE methods and inspectors demonstrate 90% Probability of Detection (POD) with 95% confidence for critical flaw sizes when inspecting fracture critical metallic components. NASA addresses the known variability of NDE inspector capability in two ways. The first, Special NDE, requires that every inspector demonstrate the required 90/95 POD, which is resource intensive. The second approach is Standard NDE for which conservative flaw sizes for different NDE methods are provided such that it is expected that most properly trained inspectors will exceed the 90/95 POD requirement. As such, individual POD demonstration testing is not required. The origin of NASA Standard NDE dates to the start of the Space Shuttle Program in the early 1970’s. In the first study to quantitatively assess NDE methods and inspectors, the performance of multiple inspectors was evaluated for different NDE methods using a large set of fatigue cracked specimens. A rudimentary POD analysis was performed to estimate the 90/95 POD flaw size for each inspector for each method. Additionally, the average and standard deviation of the 90/95 POD flaw size across the multiple inspectors was calculated to estimate the flaw size for which 95 percent of inspectors would provide the 90/95 POD capability. These estimated 90/95/95 POD flaw sizes evolved into the NASA Standard NDE flaw sizes still in use for structural analysis five decades later. The methodology for performing Standard NDE POD studies was never documented in NASA requirements. Furthermore, POD analysis methods have significantly evolved since this seminal study. Likewise, NDE methods have improved and there has been a push to reassess Standard NDE flaw sizes for existing methods, and to develop Standard NDE flaw sizes for new methods such as digital radiography. In this study, a Standard NDE POD methodology was developed and baselined using the historical data. This reanalysis of the historical data identified several deficiencies in the original test plan as well as an overall lack of conservatism in the estimated 90/95/95 POD flaw sizes. The results of this historical review and the new methodology are being incorporated into an update of NASA NDE POD requirements.

Nondestructive Evaluation↗
NASA NTRSDate not supplied

The Repair Maintenance and Fabrication Facility in the Common Habitat Architecture

The Common Habitat Architecture seeks to increase the habitability of long-duration human spaceflight systems. A key aspect of this is vehicle survivability. Missions beyond low Earth orbit need onboard capabilities for Repair, Maintenance, And Fabrication (RMAF) to overcome potential contingency scenarios. Strategies employed in historic human spaceflight such as redundancy management, reliability, sparing, orbital replacement units, and aborts may be insufficient by themselves. Based on subject matter input, a list of 53 critical failures defining a set of incidents that can render a key spacecraft subsystem inoperable were generated. A subsequent analysis found that a robust in-space RMAF system capable of performing 14 key functions can potentially repair a subsystem plagued by any of these failures. An ancillary benefit is this capability may provide psychological benefits to the crew, by enabling greater self-sufficiency in earth-independent problem solving. A basic RMAF facility has been defined for the Common Habitat, consisting of five workstations. A work bench and computer workstation provide a multipurpose horizontal work surface, computing interface, and tools storage. A CNC machining center provides a subtractive manufacturing capability for metals and plastics. A multi-material 3D printing facility provides additive manufacturing capabilities for plastic, metals, and printed electronics. A welding facility is used for joining metal components where a higher strength is needed than can be achieved with fasteners or adhesives. A glovebox facility is used to perform work that is too hazardous for any of the other workstations. This may include hardware brought in from outside the spacecraft that could potentially contaminate the cabin environment. Forward work includes considering the accommodation of additional manufacturing processes not modeled in the current system, assessing the ability of systems to operate in partial gravity and microgravity environments, incorporation of the system into the Common Habitat Computer Aided Design (CAD) model, bottoms-up mass estimating, and a crew time analysis.

Habitat↗
NASA NTRS2016

Systems and Methods for Implementing Bulk Metallic Glass-Based Strain Wave Gears and Strain Wave Gear Components

Bulk metallic glass-based strain wave gears and strain wave gear components. In one embodiment, a strain wave gear includes: a wave generator; a flexspline that itself includes a first set of gear teeth; and a circular spline that itself includes a second set of gear teeth; where at least one of the wave generator, the flexspline, and the circular spline, includes a bulk metallic glass-based material.

Hofmann, Douglas C.↗
NASA NTRSDate not supplied

Component Applications using Metal Additive Manufacturing Techniques and Materials for Rocket Propulsion

The NASA Marshall Space Flight Center (MSFC) has been involved with various forms of metallic additive manufacturing for use in liquid rocket engine component design, development, and testing since 2010. These AM techniques have been demonstrated to significantly reduce hardware cost, shorten fabrication schedules, increase reliability by reducing the number of joints, and improve hardware performance by allowing fabrication of designs not feasible by conventional means. The focus at the NASA MSFC for these metal additive manufacturing techniques include laser powder-bed fusion (L-PBF), blown powder directed energy deposition (DED) and arc-based deposition. A variety of components have been evaluated and tested including thrust chamber injectors, injector components such as faceplates, regeneratively-cooled combustion chambers, regeneratively-cooled nozzles, gas generator and preburner hardware, and augmented spark igniters. To support these component applications in harsh environments, NASA has advanced a variety of “standard” additive manufacturing alloys such as those in the superalloy-family and also evolved new alloys including GRCop-84, GRCop-42, NASA HR-1, and JBK-75. The purpose of this presentation is to discuss the various programs at the NASA MSFC using AM to develop, fabricate, and test combustion devices hardware and the evolution of the new additive alloys. Additional information will be provided on the development of multi-metallic additive manufacturing, post-processing of AM techniques including surface enhancements (polishing) techniques, material and process characterization, future development programs, and dissemination of data to industry partners.

Additive Manufacturing↗
NASA NTRS1972

Joining porous components to solid metal structures

Process for joining porous metal material to solid metal structure without cracking or blockage of porous component is described. Procedures of electron beam welding and electroforming are discussed. Illustration of microstructure resulting from process is included.

Fortini, A.↗
NASA NTRS1991

Advances in high temperature components for AMTEC (Alkali Metal Thermal-to-Electric Converter)

The basic performance of Alkali Metal Thermal-to-Electric Converter (AMTEC) cells is well understood, and quantitative modeling of the electrode performance has been carried out. Tests have been carried out to evaluate the high temperature performance of critical AMTEC components. Progress made in understanding the relative performance of AMTEC components, such as electrodes, electrolytes, working fluids, and seals, as device operating temperature is varied is discussed. Most metallic components are especially subject to corrosion in hot liquid alkali metals containing dissolved oxides. Stability issues of AMTEC components may be addressed by life testing, accelerated testing, and modeling based on known kinetic and thermochemical data.

Williams, R. M.↗
NASA NTRS1972

A technique for making clean holes in metallic piping and components

Testing was conducted to develop a technique of providing clean holes in process piping or in a metal surface accessible from one side only without disassembling the system. The method was performed on sample pieces of piping and worked successfully with no contaminants being found on the inside of the pipe. The materials tested were Inconel 600, 304 stainless steel, Hastelloy X, and ASTM-A53 black steel. The technique was developed such that it could be done in the field with hand-held power tools and a portable tungsten inert gas welding machine.

Hecker, T. P.↗