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At least 1,279 records · Page 71

Robust Metal Additive Manufacturing Process Selection and Development for Aerospace Components

Metal additive manufacturing (AM) is a generic term that captures a variety of fabrication techniques. Each of these manufacturing process has unique advantages, applications for use, and challenges. The most common AM processes in use include Powder Bed Fusion (PBF) and Directed Energy Deposition (DED) as well as many solid state processes. While detailed research has been conducted among many of the processes including parameters and material properties, navigating which processes are best to select is difficult as it is based on component requirements. The focus of this presentation is to provide an overview of considerations for each of metal AM process selection for aerospace components based on various attributes. These attributes include geometric considerations, metallurgical characteristics, cost basis, post-processing and maturity of the processes. The data for these trade selections are based on studies that NASA as performed internally and with academic and industry partners. These studies include multiple AM build experiments to evaluate (1) geometric variations and constraints within the processes, (2) alloy characterization and mechanical testing, (3) pathfinder component development and hotfire evaluations, and (4) certification approaches. This presentation summarizes these results and meant to introduce various considerations when designing a metal AM component.

Additive Manufacturing↗

Development of Materials Processing Systems for Use in Space on Low-g Simulation Devices

Advanced furnace systems are being developed for use in space. Systems are being tested for current experiment applications and modified for future experiment requirements. Future projects are: (1) fabrication and testing of the Advanced Automated Directional Solidification Furnace (AADSF) flight hardware; (2) development of a Heat Pipe Furnace (HPF) for use in space. Heat pipes will be tested for space flight qualification in conjunction with the furnace development. The HPF design will be based on the AADSF development and will be of modular design including capabilities of operating with or without heat pipes; and (3) the AADSF furnace will be modified and tested to operate at temperatures up to 1700 C in the heated cavity. This will be accomplished by developing a new hot end heating module and insulation package for the existing AADSF. Refurbishment of the Drop Tower Furnace (DTF) is under way. The DTF can operate at temperatures up to 1700 C. The sample size will be approximately 3/8 in. dia. x 5/8 in. long. Design improvements for the General Purpose Rocket Furnace (GPRF) for use in the Material Experiment Assembly (MEA) are to be accomplished.

Aldrich, B. R.↗

Development of data processing, interpretation and analysis system for remote sensing of trace atmospheric gas species

Highly efficient methods were developed for the analysis and reduction of Measurement of Air Pollution from Satellite (MAPS) data. Specific attention was directed to analyzing the data from the Office of Space and Terrestrial Applications 3 (OSTA-3) correlative measurements of aircraft research flights and from the OSTA-3 shuttle flight. Methods were developed for error analysis of the aircraft and spacecraft instruments. The LSI 11/23 software system was modified and expanded for future data analysis.

Gormsen, B. B.↗

Development of the activated diffusion brazing process for fabrication of finned shell to strut turbine blades

The activated diffusion brazing process was developed for attaching TD-NiCr and U700 finned airfoil shells to matching Rene 80 struts obstructing the finned cooling passageways. Creep forming the finned shells to struts in combination with precise preplacement of brazing alloy resulted in consistently sound joints, free of cooling passageway clogging. Extensive tensile and stress rupture testing of several joint orientation at several temperatures provided a critical assessment of joint integrity of both material combinations. Trial blades of each material combination were fabricated followed by destructive metallographic examination which verified high joint integrity.

Wilbers, L. G.↗

Development of data processing interpretation and analysis system for the remote sensing of trace atmospheric gas species

Problems associated with the development of the measurement of air pollution from satellites (MAPS) experiment program are addressed. The primary thrust of this research was the utilization of the MAPS experiment data in three application areas: low altitude aircraft flights (one to six km); mid altitude aircraft flights (eight to 12 km); and orbiting space platforms. Extensive research work in four major areas of data management was the framework for implementation of the MAPS experiment technique. These areas are: (1) data acquisition; (2) data processing, analysis and interpretation algorithms; (3) data display techniques; and (4) information production.

Casas, J. C.↗

Developments of Bosch Process Architectures for ISRU Terrestrial Applications

To effectively realize NASA’s goals of a sustainable presence on the Moon and be-yond, In-Situ Resource Utilization (ISRU) must be leveraged. To reduce launch mass for space missions, commodities such as oxygen and carbon can be produced in-situ. Oxygen can be used for life support and as a propellant, and carbon can be used for battery production, filtration, additive manufacturing, and steel casting. Carbon is a required reactant in the carbothermal reduction process, a leading candidate for oxygen production on the lunar surface. To pro-duce these consumables, the Carbon Utilization Technology for Lunar and Atmospheric Systems (CUTLAS) project is developing architectures that leverage the Bosch process. The Bosch process re-acts CO 2 and H 2 to produce carbon powder and water, which can then be electrolyzed, leaving O 2 and recycled H 2 . This process is also applicable to carbon dioxide emissions on Earth.

Carbon capture↗

Laser-zone growth in a Ribbon-To-Ribbon (RTR) process silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

The Ribbon-to-Ribbon (RTR) approach to silicon ribbon growth was investigated. An existing RTR apparatus, RTR#1, was upgraded to allow for 5 cm wide ribbon growth with a finite stroke length of at least 15 cm. A second RTR apparatus, RTR#2, was designed, built, and operated which utilizes continuous feed mechanisms and allows continuous growth of 7.5 cm wide ribbons. RTR#2 includes development and utilization of advanced beam scanning (or shaping), high power lasers, and thermal profile modification elements to attain maximum growth velocities (with a design goal of 18 cm/min). Materials studies, process development, and thermal analyses are also described. Residual stresses and dislocation densities were minimized through theoretical and experimental efforts towards optimization of thermal profiles. Growth runs were performed on RTR#2 and solar cells were fabricated which demonstrated efficiencies greater than 10%.

Gurtler, R. W.↗

The Nasa SRA Process as It Relates to Open-Source Workflows Developed for GeneLab Data Processing

To release open, standards-compliant processed data sets in the Open Science Data Repository (OSDR), the GeneLab Data Processing team works with the scientific community through the OSDR Analysis Working Groups to design and build open-source data processing pipelines. Once baselined internally, these pipelines are wrapped into workflows and published on the NASA GeneLab Data Processing public GitHub repository along with detailed instructions for installation and use. Each workflow must be approved through NASA's Software Release Authorization (SRA) process prior to publishing. However, the SRA process lacks sufficient documentation and clarity regarding which forms are applicable for new open-source software that utilizes publicly available 3rd party tools, and the SRA process can take several months to complete, making sharing software outside of NASA cumbersome and in contradiction with the concept of Open Science. Furthermore, the SRA process was designed as a one-size fits all approach and thus many of the questions asked are not applicable to our open-source workflows. Here we describe the software provided on the NASA GeneLab Data Processing GitHub repository, summarize our experiences with the SRA process to release these software, and propose a more stream-lined approach for review of open-source projects.

Software Release Authorization↗

The NASA SRA Process as it Relates to Open-Source Workflows Developed for GeneLab Data Processing

To release open, standards-compliant processed data sets in the Open Science Data Repository (OSDR), the GeneLab Data Processing team works with the scientific community through the OSDR Analysis Working Groups to design and build open-source data processing pipelines. Once baselined internally, these pipelines are wrapped into workflows and published on the NASA GeneLab Data Processing public GitHub repository along with detailed instructions for installation and use. Each workflow must be approved through NASA's Software Release Authorization (SRA) process prior to publishing. However, the SRA process lacks sufficient documentation and clarity regarding which forms are applicable for new open-source software that utilizes publicly available 3rd party tools, and the SRA process can take several months to complete, making sharing software outside of NASA cumbersome and in contradiction with the concept of Open Science. Furthermore, the SRA process was designed as a one-size fits all approach and thus many of the questions asked are not applicable to our open-source workflows. Here we describe the software provided on the NASA GeneLab Data Processing GitHub repository, summarize our experiences with the SRA process to release these software, and propose a more stream-lined approach for review of open-source projects.

Software Release Authorization↗

Development of metallization process: FSA project, cella and module formation research area

The optimization, evaluation, and demonstration of a novel metallization applied by a screen printing process is examined. Based on previous results of High Resolution, Low Cost Solar Cell Contact Development, a paste consisting of molybdenum, tin, and titanium hydride was selected as the promising composition. No satisfactory cells were made using any of the molybdenum/tin pastes used as a complete replacement for conventional silver pastes. The major problem is the inability to form a bond between the pastes and silicon that withstands soldering.

Garcia, A., III↗

A Software Development Simulation Model of a Spiral Process

There is a need for simulation models of software development processes other than the waterfall because processes such as spiral development are becoming more and more popular. The use of a spiral process can make the inherently difficult job of cost and schedule estimation even more challenging due to its evolutionary nature, but this allows for a more flexible process that can better meet customers' needs. This paper will present a discrete event simulation model of spiral development that can be used to analyze cost and schedule effects of using such a process in comparison to a waterfall process.

Mizell, Carolyn↗

Development of a process for high capacity-arc heater production of silicon

The realization of low cost, electric power from large-area silicon, photovoltaic arrays will depend on the development of new methods for large capacity production of solar grade (SG) silicon with a cost of less than $10 per kilogram by 1986 (established Department of Energy goal). The objective of the program is to develop a method to produce SG silicon in large quantities based on the high temperature-sodium reduction of silicon tetrachloride (SiCl4) to yield molten silicon and the coproduct salt vapor (NaCl). Commercial ac electric arc heaters will be utilized to provide a hyper-heated mixture of argon and hydrogen which will furnish the required process energy. The reactor is designed for a nominal silicon flow rate of 45 kg/hr. Analyses and designs have been conducted to evaluate the process and complete the initial design of the experimental verification unit.

Reed, W. H.↗

Status of the Development of Flight Power Processing Units for the NASAs Evolutionary Xenon Thruster - Commercial (NEXT-C) Project

A pathfinder prototype unit and two flight power processing units (PPUs) are being developed by the Aerojet Rocketdyne Corporation in Redmond, Washington and ZIN Technologies in Cleveland, Ohio, in support of the NEXT-C Project. This project is being led by the NASA Glenn Research Center in Cleveland, Ohio, and will also yield two flight thrusters. This hardware is being considered to be provided as Government Furnished Equipment for the New Frontiers Program, and is applicable to a variety of planetary science missions and astrophysics science missions. The design of the NEXT-C PPU evolves from the hardware fabricated under the NEXT technology development project. The power processing unit operates from two sources: a wide input 80 to 160 V high-power bus and a nominal 28 V low-power bus. The unit includes six power supplies. Four power supplies (beam, accelerator, discharge, and neutralizer keeper) are needed for steady state operation, while two cathode heater power supplies (neutralizer and discharge) are utilized during thruster startup. The unit in total delivers up to 7 kW of regulated power to a single gridded-ion thruster. Significant modifications to the initial design include: high-power adaptive-delay control, upgrade of design to EEE-INST-002 compliance, telemetry accuracy improvements, incorporation of telemetry to detect plume-mode operation, and simplification of the design in select areas to improve manufacturability and commercialization potential. The project is presently in the prototype phase and preparing for qualification level environmental testing.

NASAaEuro(TM)s Evolutionary Xenon Thruster↗

Spacelab Data Processing Facility (SLDPF) quality assurance expert systems development

Spacelab Data Processing Facility (SLDPF) expert system prototypes were developed to assist in the quality assurance of Spacelab and/or Attached Shuttle Payload (ASP) processed telemetry data. The SLDPF functions include the capturing, quality monitoring, processing, accounting, and forwarding of mission data to various user facilities. Prototypes for the two SLDPF functional elements, the Spacelab Output Processing System and the Spacelab Input Processing Element, are described. The prototypes have produced beneficial results including an increase in analyst productivity, a decrease in the burden of tedious analyses, the consistent evaluation of data, and the providing of concise historical records.

Kelly, Angelita C.↗

Spacelab Data Processing Facility (SLDPF) quality assurance expert systems development

Spacelab Data Processing Facility (SLDPF) expert system prototypes have been developed to assist in the quality assurance of Spacelab and/or Attached Shuttle Payload (ASP) processed telemetry data. SLDPF functions include the capturing, quality monitoring, processing, accounting, and forwarding of mission data to various user facilities. Prototypes for the two SLDPF functional elements, the Spacelab Output Processing System and the Spacelab Input Processing Element, are described. The prototypes have produced beneficial results including an increase in analyst productivity, a decrease in the burden of tedious analyses, the consistent evaluation of data, and the providing of concise historical records.

Kelly, Angelita C.↗

Modular 5-kW Power-Processing Unit Being Developed for the Next-Generation Ion Engine

The NASA Glenn Research Center is developing a 5- to 10-kW ion engine for a broad range of mission applications. Simultaneously, a 5-kW breadboard power-processing unit (PPU) is being designed and fabricated by Boeing Electron Dynamic Devices, Torrance, California, under contract with Glenn. The beam supply, which processes up to 90 percent of the power into this unit, consists of four 1.1-kW power modules connected in parallel, equally sharing the output current. The modular design allows scalability to higher powers as well as the possibility of implementing an N + 1 redundant beam supply. A novel phaseshifted/pulse-width-modulated, dual full-bridge topology was chosen for this module design for its efficient switching characteristics. A breadboard version of the beam power supply module was assembled. Efficiencies ranging between 91.6 and 96.9 percent were measured for an input voltage range of 80 to 160 V, an output voltage range of 800 to 1500 V, and output powers from 0.3 to 1.0 kW. This beam supply could result in a PPU with a total efficiency between 93 and 95 percent at a nominal input voltage of 100 V. This is up to a 4-percent improvement over the state-of-the-art PPU used for the Deep Space 1 mission. A flight-packaged PPU is expected to weigh no more than 15 kg, which represents a 50-percent reduction in specific mass from the Deep Space 1 design. This will make 5-kW ion propulsion very attractive for many planetary missions.

Pinero, Luis R.↗

Development of signal processing algorithms for ultrasonic detection of coal seam interfaces

A pattern recognition system is presented for determining the thickness of coal remaining on the roof and floor of a coal seam. The system was developed to recognize reflected pulse echo signals that are generated by an acoustical transducer and reflected from the coal seam interface. The flexibility of the system, however, should enable it to identify pulse-echo signals generated by radar or other techniques. The main difference being the specific features extracted from the recorded data as a basis for pattern recognition.

Purcell, D. D.↗

Development of the silane process for the production of low-cost polysilicon

It was recognized that the traditional hot rod type deposition process for decomposing silane is energy intensive, and a different approach for converting silane to silicon was chosen. A 1200 metric tons/year capacity commercial plant was constructed in Moses Lake, Washington. A fluidized bed processor was chosen as the most promising technology and several encouraging test runs were conducted. This technology continues to be very promising in producing low cost polysilicon. The Union Carbide silane process and the research development on the fluidized bed silane decomposition are discussed.

Iya, S. K.↗