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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Influence of Oxygenated Compounds on Reaction Products in a Microwave Plasma Methane Pyrolysis Assembly for Post-Processing of Sabatier Methane

The state-of-the-art Carbon Dioxide Reduction Assembly (CRA) was delivered to the International Space Station (ISS) in April 2010. The system is designed to accept carbon dioxide from the Carbon Dioxide Removal Assembly and hydrogen from the Oxygen Generation Assembly. The two gases are reacted in the CRA in a Sabatier reactor to produce water and methane. Venting of methane results in an oxygen resupply requirement of about 378 lbs per crew member per year. If the oxygen is supplied as water, the total weight for resupply is about 476 lb per crew member per year. For long-term missions beyond low Earth orbit, during which resupply capabilities will be further limited, recovery of hydrogen from methane is highly desirable. For this purpose, NASA is pursuing development of a Plasma Pyrolysis Assembly (PPA) capable of recovering hydrogen from methane. Under certain conditions, water vapor and carbon dioxide (nominally intended to be separated from the CRA outlet stream) may be present in the PPA feed stream. Thus, testing was conducted in 2010 to determine the effect of these "oxygenated" compounds on PPA performance, particularly the effect of inlet carbon dioxide and water variations on the PPA product stream. This paper discusses the test set-up, analysis, and results of this testing

Mansell, J. Matthew↗
NASA NTRS2012

Influence of Oxygenated Compounds on Reaction Products in a Microwave Plasma Methane Pyrolysis Assembly for Post-Processing of Sabatier Methane

The state-of-the-art Carbon Dioxide Reduction Assembly (CRA) was delivered to the International Space Station (ISS) in April 2010. The system is designed to accept carbon dioxide from the Carbon Dioxide Removal Assembly and hydrogen from the Oxygen Generation Assembly. The two gases are reacted in the CRA in a Sabatier reactor to produce water and methane. Venting of methane results in an oxygen resupply requirement of about 378 lbs per crew member per year. If the oxygen is supplied as water, the total weight for resupply is about 476 lb per crew member per year. For long-term missions beyond low Earth orbit, during which resupply capabilities will be further limited, recovery of hydrogen from methane is highly desirable. For this purpose, NASA is pursuing development of a Plasma Pyrolysis Assembly (PPA) capable of recovering hydrogen from methane. Under certain conditions, water vapor and carbon dioxide (nominally intended to be separated from the CRA outlet stream) may be present in the PPA feed stream. Thus, testing was conducted in 2010 to determine the effect of these oxygenated compounds on PPA performance, particularly the effect of inlet carbon dioxide and water variations on the PPA product stream. This paper discusses the test set-up, analysis, and results of this testing.

Mansell, J. Matthew↗
NASA NTRS2002

Design and Manufacturing Processes of Long-Life Hollow Cathode Assemblies

The design and manufacturing processes for Hollow Cathode Assemblies (HCA's) that operate over a broad range of emission currents up to 30 Amperes, at low potentials, with lifetimes in excess of 17,500 hours. The processes include contamination control procedures which cover hollow cathode component cleaning procedures, gas feed system designs and specifications, and hollow cathode activation and operating procedures to thereby produce cathode assemblies that have demonstrated stable and repeatable operating conditions, for both the discharge current and voltage. The HCA of this invention provides lifetimes of greater than 10,000 hours, and expected lifetimes of greater than 17,500 hours, whereas the present state-of-the-art is less than 500 hours at emission currents in excess of 1 Ampere. Stable operation is provided over a large range of operating emission currents, up to a 6:1 ratio, and this HCA can emit electron currents of up to 30 Amperes in magnitude to an external anode that simulates the current drawn to a space plasma at voltages of less than 20 Volts.

Michael J Patterson↗
NASA NTRS2001

Processes For Cleaning a Cathode Tube and Assemblies In A Hollow Cathode Assembly

The present invention is a process for cleaning a cathode tube and other subassemblies in a hollow cathode assembly. In the disclosed process, hand covering elastomer gloves are used for handling all cathode assembly parts. The cathode tube and other subassemblies are cleaned with a lint-free cloth damped with acetone, then wiped with alcohol, immersed in ethyl alcohol or acetone, and ultrasonic agitation is applied, heating to 60 C. for ethyl alcohol or 56 C. for acetone. The cathode tube and other subassemblies are dried by blowing with nitrogen gas.

Patterson, Michael J.↗
NASA NTRS2001

Fabrication process for combustion chamber/nozzle assembly

An integral, lightweight combustion chamber/nozzle assembly for a rocket engine has a refractory metal shell defining a chamber of generally frusto-conical contour. The shell communicates at its smaller end with a rocket body, and terminates at its larger end in a generally contact contour, which is open at its terminus and which serves as a nozzle for the rocket engine. The entire inner surface of the refractory metal shell has a thermal and oxidation barrier layer applied thereto. An ablative silica phenolic insert is bonded to the exposed surface of the thermal and oxidation barrier layer. The ablative phenolic insert provides a chosen inner contour for the combustion chamber and has a taper toward the open terminus of the nozzle. A process for fabricating the integral, lightweight combustion chamber/nozzle assembly is simple and efficient, and results in economy in respect of both resources and time.

Myers, W. Neill↗
NASA NTRS1990

Computer Assembles Mosaics Of Satellite-SAR Imagery

Digital image-processing system assembles maplike mosaic images of large areas of Earth from overlapping images of smaller areas generated by spaceborne synthetic-aperture radar (SAR). Automatically registers and blends smaller images with each other. Eliminates need for time-consuming, tedious manual processing. Modifiable to accept images from spaceborne optical sensors.

Kwok, R.↗
NASA NTRS2022

Advanced Lightweight Metallic Fuselage Project Manufacturing Trade Study

Recent advances in large-scale flow forming of integrally stiffened cylinders (ISCs) have motivated evaluation of available technologies for rapid manufacturing of metallic fuselages. The current state-of-the-art in flow forming of ISCs produces 10-ft. diameter, 5-ft. long barrels with integral longitudinal blade stiffeners, and these single-piece ISCs are produced in approximately 1.5 hours. While other manufacturing processes are required to incorporate additional structural elements (ASE) such as circumferential ring frames, reinforcements around window and door cut-outs, and floors to the ISCs to complete the fuselage structure, flow forming technology may assist the aerospace industry in meeting manufacturing rate demands. In order to evaluate this technology, a fuselage manufacturing demonstration article (MDA) fabricated from two ISCs is scheduled for fabrication and delivery to NASA Langley Research Center (LaRC) by the end of 2022. In this study, eight manufacturing technologies were assessed to downselect candidate manufacturing processes for adding ASE to complete the MDA. A literature review and evaluation of contractor-produced panels covering a spectrum of welding and additive manufacturing (AM) processes were conducted at NASA LaRC. The analytical hierarchy process (AHP) was used to evaluate figures of merit (FOMs) for selecting manufacturing process(es) to integrate ASE with the ISCs to form a fuselage MDA. The AHP results revealed that scalability, structural performance, and distortion control were the most valued criteria for downselecting the manufacturing process to construct the internal stiffening structures. Based on the FOMs, this study concluded that a welding process is best suited for integrating the majority of the ASE, namely the circumferential ring frames. All of the welding processes received higher scores than AM processes due to higher maturity, higher structural performance, fewer post-processing requirements in machining and heat treating, and faster deposition rates. Among the welding processes, cold metal transfer (CMT) welding was ranked the most favorable process for assembling the MDA, with the other welding processes (laser welding (LW), friction stir welding (FSW), and refill friction stir spot welding (RFSSW)) scoring slightly lower. This was a consequence of the perceived maturity of the CMT welding process and its relatively high structural performance and low distortion resulting from the low heat input. Among the AM processes, CMT AM showed the greatest promise due to benefits derived from its scalability, lower 1st order process complexity, and low distortion. The AM processes may have potential for select applications, such as adding structural reinforcements around window and door cut-outs, but are not considered optimal for integrating the entire MDA.

Manufacturing↗
NASA NTRS1979

Automated aray assembly, phase 2

A manufacturing process suitable for the large-scale production of silicon solar array modules at a cost of less than $500/peak kW is described. Factors which control the efficiency of ion implanted silicon solar cells, screen-printed thick film metallization, spray-on antireflection coating process, and panel assembly are discussed. Conclusions regarding technological readiness or cost effectiveness of individual process steps are presented.

Daiello, R. V.↗
NASA NTRS1987

Intelligent laser soldering inspection and process control

Component assembly on printed circuitry keeps making giant strides toward denser packaging and smaller dimensions. From a single layer to multilayer, from through holes to surface mounted components and tape applied bonds, unrelenting progress results in new, difficult problems in assembling, soldering, inspecting and controlling the manufacturing process of the new electronics. Among the major problems are the variables introduced by human operators. The small dimensions and the tight assembly tolerances are now successfully met by machines which are faster and more precise than the human hand. The same is true for soldering. But visual inspection of the solder joints is now so severely limited by the ever shrinking area accessible to the human eye that the inspector's diagnosis cannot be trusted any longer. Solutions to correcting these problems are discussed.

Vanzetti, Riccardo↗
NASA NTRS1973

Process for making RF shielded cable connector assemblies and the products formed thereby

A process for making RF shielded cable connector assemblies and the resulting structures is described. The process basically consists of potting wires of a shielded cable between the cable shield and a connector housing to fill in, support, regidize, and insulate the individual wires contained in the cable. The formed potting is coated with an electrically conductive material so as to form an entirely encompassing adhering conductive path between the cable shield and the metallic connector housing. A protective jacket is thereby formed over the conductive coating between the cable shield and the connector housing.

Fisher, A.↗
NASA NTRS1991

A process for preparing an assembly of an article and a polyimide which resists dimensional change, delamination, and debonding when exposed to changes in temperature

An assembly of an article and a polyimide composition is prepared. The assembly resists dimensional change, delamination, or debonding when exposed to changes to temperature. An article is provided. A polyamic acid solution which yields a polyimide having a low coefficient of thermal expansion (CTE) was prepared. Equimolar quantities of an aromatic diamine and an aromatic dianhydride were reacted in a solvent medium to form a polyamic acid solution. A metal ion containing additive was added to the solution. Examples of this additive are: TbCl3, DyCl3, ErCl3, TmCl3, Al(C5H7O2)3, and Er2S3. The polyamic acid solution was imidized and is combined with the article to form the assembly.

Stoakley, Diane M.↗
NASA NTRS1993

A process for preparing an assembly of an article and a soluble polyimide which resists dimensional change, delamination, and debonding when exposed to changes in temperature

An assembly of an article and a polyimide is prepared. The assembly resists dimensional change, delamination, or debonding when exposed to changes in temperature. An article is provided. A soluble polyimide resin solution having a low coefficient of thermal expansion (CTE) was prepared by dissolving the polyimide in solvent and adding a metal ion-containing additive to the solution. Examples of the additive are: Ho(OOCCH3), Er(NPPA)3, TmCl3, and Er(C5H7O2)3. The soluble polyimide resin is combined with the article to form the assembly.

Stoakley, Diane M.↗
NASA NTRS1994

Process for preparing an assembly of an article and a polyimide which resists dimensional change, delamination and debonding when exposed to changes in temperature

An assembly of an article and a polyimide composition is prepared. The assembly resists dimensional change, delamination, or debonding when exposed to changes in temperature. An article is provided. A polyamic acid solution which yields a polyimide having a low coefficient of thermal expansion (CTE) was prepared. Equimolar quantities of an aromatic diamine and an aromatic dianhydride were reacted in a solvent medium to form a polyamic acid solution. A metal ion-containing additive was added to the solution. Examples of this additive are: TbCl3, DyCl3, ErCl3, TmCl3, Al(C5H7O2)3, and Er2S3. The polyamic acid solution was imidized and is combined with the article to form the assembly.

Stoakley, Diane M.↗
NASA NTRS1989

Hybrid Analog/Digital Receiver

Advanced hybrid analog/digital receiver processes intermediate-frequency (IF) signals carrying digital data in form of phase modulation. Uses IF sampling and digital phase-locked loops to track carrier and subcarrier signals and to synchronize data symbols. Consists of three modules: IF assembly, signal-processing assembly, and test-signal assembly. Intended for use in Deep Space Network, but presumably basic design modified for such terrestrial uses as communications or laboratory instrumentation where signals weak and/or noise strong.

Brown, D. H.↗
NASA NTRS1985

The use of analogs in the innovation process - A software engineering protocol analysis

A human information processing account of how experienced practitioners utilize analogs in the innovation process is presented. The protocols of several practitioners are collected and analyzed. The problem behavior graphs, knowledge elements utilized, and operator elements applied are described, and a descriptive model of the innovation process is assembled. Implications for a production system, deviations from other models of the innovation process, and extensions to other models of the analogy procedure are explored.

Silverman, B. G.↗
NASA NTRS1998

Continuous Process Involvement

The Electronic Fabrication Section at the Jet Propulsion Laboratories (JPL) has been studying ways to improve Printed Wiring Assembly (PWA) processes. The PWA study described here contained typical surface mount devices including 20 mil fine pitch devices and various BGAs.

surface mount component component lead forming lea↗