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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS2005

Putting EVM to the Test

IN MANY INSTANCES THERE IS NO FOREWARNING; SCHEDULES slip, costs soar, and the project manager is faced with the near impossible task of explaining why each impact occurred. With contractors performing the majority of the work, the management job can become even more obscure. The simple lack of proximity to the contractor can limit effective communication. Add to that a mixture of cultural differences and a desire for the contractor to portray the most optimistic view of their performance, and you create an even more difficult task for the project manager. This was the scenario when the Habitat Holding Rack (HHR) manager at Marshall Space Flight Center (MSFC), Stacy Counts, was introduced to the overall concept of Earned Value Management (EVM). Faced with increased costs (which eventually resulted in decreased scope of the project), continued schedule slides, and several technical anomalies, she was looking for a way to gain a better handle on the project performance. As a component of the Space Station Biological Research Program (SSBRP), the HHR project is an integral piece of the Program content. The HHR is the first rack hardware to be delivered for the Program and has therefore been the first rack to move through the trials of test and verification-documenting anomalies and technical difficulties that will benefit the other SSBRP rack projects. For these reasons, the HHR maintained high visibility throughout the manufacturing and assembly process, continuing through test and verification activities. Needless to say, the higher visibility emphasized the need for improved performance on this project. And to improve project performance, Stacy first had to figure out how to measure the cost, schedule and technical objectives effectively.

Kerby, Jerald↗
NASA NTRS1995

Prototype development and test results of a continuous ambient air monitoring system for hydrazine at the 10 ppb level

A Hydrazine Vapor Area Monitor (HVAM) system is currently being field tested as a detector for the presence of hydrazine in ambient air. The MDA/Polymetron Hydrazine Analyzer has been incorporated within the HVAM system as the core detector. This analyzer is a three-electrode liquid analyzer typically used in boiler feed water applications. The HVAM system incorporates a dual-phase sample collection/transport method which simultaneously pulls ambient air samples containing hydrazine and a very dilute sulfuric acid solution (0.0001 M) down a length of 1/4 inch outside diameter (OD) tubing from a remote site to the analyzer. The hydrazine-laden dilute acid stream is separated from the air and the pH is adjusted by addition of a dilute caustic solution to a pH greater than 10.2 prior to analysis. Both the dilute acid and caustic used by the HVAM are continuously generated during system operation on an "as needed" basis by mixing a metered amount of concentrated acid/base with dilution water. All of the waste water generated by the analyzer is purified for reuse by Barnstead ion-exchange cartridges so that the entire system minimizes the generation of waste materials. The pumping of all liquid streams and mixing of the caustic solution and dilution water with the incoming sample are done by a single pump motor fitted with the appropriate mix of peristaltic pump heads. The signal to noise (S/N) ratio of the analyzer has been enhanced by adding a stirrer in the MDA liquid cell to provide mixing normally generated by the high liquid flow rate designed by the manufacturer. An onboard microprocessor continuously monitors liquid levels, sample vacuum, and liquid leak sensors, as well as handles communications and other system functions (such as shut down should system malfunctions or errors occur). The overall system response of the HVAM can be automatically checked at regular intervals by measuring the analyzer response to a metered amount of calibration standard injected into the dilute acid stream. The HVAM system provides two measurement ranges (threshold limit value (TLV): 10 to 1000 parts per billion (ppb)/LEAK: 100 ppb to 10 parts per million (ppm)). The LEAK range is created by dilution of the sulfuric acid/hydrazine liquid sample with pure water. This dual range capability permits the analyzer to quantify ambient air samples whose hydrazine concentrations range from 10 ppb to as high as 10 ppm. The laboratory and field prototypes have demonstrated total system response times on the order of 10 to 12 minutes for samples ranging from 10 to 900 ppb in the lLV mode and is greater than 2 minutes for samples ranging from 100 to 1300 ppb in the LEAK mode. Service intervals of over 3 months have been demonstrated for continuous 24 hour/day, 7 day/week usage. The HVAM is made up of a purged cabinet that contains power supplies, RS422 signal transmission capabilities, a UPS, an on-site warning system, and a Line Replaceable Unit (LRU). The LRU includes all of the liquid flow system, the analyzer, the control/data system microprocessor and assorted flow and liquid-level sensors. The LRU is mounted on a track slide system so it can be serviced inplace or totally removed and quickly exchanged with another calibrated unit, thus minimizing analyzer downtime. Once an LRU is removed from an analyzer enclosure, it can be brought to a laboratory facility for complete calibration and periodic maintenance.

Meneghelli, Barry↗
NASA NTRSDate not supplied

Toward a Fully Capable In-Space Manufacturing Ecosystem

As technology for in-space refueling and servicing continues to mature, in-space assembly and manufacturing efforts can expand to leverage these new capabilities. This paper expands upon previous work and describes four use cases for a fully capable in-space manufacturing ecosystem. Based on those use cases, enabling technology areas are identified and shortfalls in those technologies are noted for seven key categories. Finally, a survey of options for in-space experiments and demonstrations are presented, showing pathways for technology development in relevant environments.

in-space manufacturing ecosystem↗
NASA NTRS1988

Space Station design integration

This paper discusses the top Program level design integration process which involves the integration of a US Space Station manned base that consists of both US and international Elements. It explains the form and function of the Program Requirements Review (PRR), which certifies that the program is ready for preliminary design, the Program Design Review (PDR), which certifies the program is ready to start the detail design, and the Critical Design Review (CDR), which certifies that the program is completing a design that meets the Program objectives. The paper also discusses experience, status to date, and plans for continued system integration through manufacturing, testing and final verification of the Space Station system performance.

Carlisle, Richard F.↗
NASA NTRS1996

Phase 9 Fiber Optic Cable Microbending and Temperature Cycling Tests

Optical fibers represent the back bone of the current communications networks. Their performance in the field lacks long term testing data because of the continuous evolution of the manufacturing of fibers and cables. An optical fiber cable that is installed in NASA's KSC has experienced a dramatic increase in attenuation after three years of use from 0.7 dB/km to 7 dB/km in some fibers. A thorough study is presented to assess the causes of such an attenuation increase. Material and chemical decomposition testing showed that there are no changes in the composition of the fiber which might have caused the increase in attenuation. Microbending and heat cycling tests were performed on the cable and individual fibers. It was found that the increase in attenuation is due to microbending caused by excessive stress exerted on the fibers. This was the result of manufacturing and installation irregularities.

Abushagur, Mustafa A.G.↗
NASA NTRS1994

Thermoplastic polymides and composites therefrom

A new class polyimide and polyimide precursors based on diaryl oxyalkylene diamines, such as 1,3-bis[4-aminophenoxy]-2,2-dimethyl propane, a process for their preparation and their use as the continuous phase for the manufacture of composites and composite laminates reinforced by reinforcing agents such as carbon fibers, Kevlar.TM., and other similar high strength reinforcing agents. The polyimides and molecular composites obtained from the diamines according to the invention show thermoplastic properties, excellent flex fatigue and fracture resistance, and excellent thermal and oxidative stability.

Harris, Frank W.↗
NASA NTRS2019

Hypervelocity Impact Performance of 3D Printed Aluminum Panels

With the continued development of additive manufacturing methods, control over the shape of ligaments, cell regularity, and macroscopic shape can all be easily tuned. This capability allows for tailoring of component architecture and promotes potential mass savings in a space vehicle structure. Additionally, it allows one the flexibility of combining structural elements such as MMOD protection and vehicle stiffness for launch loads for an overall mass reduction. At NASA JSC this technology is being explored in many different ways with the goal being a multifunctional structural component. For this study, four different types of aluminum panels have been 3D printed for testing, three being of a body centric cubic (BCC) lattice structure core and one being kelvin cell structure core. All samples have a 5.33 cm (0.05”) nominally thick aluminum face sheet printed on the front and back side of each panel, with all core materials having a 5.08 cm (2.0”) nominal thickness (see Table 1 for test sample summary and Figures 1 – 2 for sample illustrations). These tests will evaluate the performance of 3D printed aluminum panels under hypervelocity impact (HVI) conditions. The hypervelocity impact tests are being conducted at the JSC White Sands Test Facility (WSTF) Remote Hypervelocity Test Laboratory (RHTL), located in Las Cruces, New Mexico. All tests will be conducted with a 3.4mm Al 2017-T4 sphere at 6.8 km/s impacting at 0° to surface normal (i.e., impacting with no obliquity). Each sample will be trapped between two metal frames, with gasket material residing between the sample and frame, which will be the shipping and testing configuration for all tests. There will be an Al 2017-T4 witness plate staged 5.08 cm (2.0”) from each sample to capture signature of debris, if the rear face sheet of the sample were to perforate from the HVI test event.

Davis, B. A.↗
NASA NTRSDate not supplied

Analysis of Pull Force Test Results for Crimped Connections

Crimped electrical contacts are reliable when strict process controls are followed during manufacturing and accompanied by continuous process verification through pull force testing. Cable and wire harness assemblies’ standards are developed and refined over time to provide the minimum pull force that a crimp contact must meet before it breaks from the wire. However, in practice the failures occur at a much higher tensile strength than the minimum required. The first section of this paper reviewed 780 pull force test results provided by NASA Centers that were collected and analyzed to determine how the data compare to NASA’s pre-existing requirements from the cable/harness standards NASA-STD-8739.4 and IPC/WHMA-A-620B-S. The measured tensile strength of most of the contact/conductor pairs (i.e., Contact/Wires or C/W) exceeded the minimum pull force values of NASA-STD-8739.4 and IPC/WHMA-A-620 standards by at least 100%. The C/W pair samples’ tensile strength values followed a normal distribution with an average tensile strength value that was at least 182% of the minimum requirement, and all the samples analyzed passed the pull force testing. In addition, the 95% confidence interval of the average tensile strength distributions for several C/W pairs was determined and plotted as error bars to show that the C/W pairs will meet and surpass the requirements. The frequency of pull force testing can be problematic for projects because of the cost and availability of spare contacts for the destructive test. It is possible to reduce the frequency of pull force testing if at the beginning of the production run, the conditions of the crimp tool and materials are verified, and the settings of the tool remain unchanged throughout the process. However, the project needs to understand and evaluate the impact to risk from reducing the frequency of testing prior to implementing process changes.

Alejandra Constante↗
NASA NTRSDate not supplied

Analysis of Pull Force Test Results for Crimped Connections

Crimped electrical contacts are reliable when strict process controls are followed during manufacturing and accompanied by continuous process verification through pull force testing. Cable and wire harness assemblies’ standards are developed and refined over time to provide the minimum pull force that a crimp contact must meet before it breaks from the wire. However, in practice the failures occur at a much higher tensile strength than the minimum required. The first section of this paper reviewed 780 pull force test results provided by NASA Centers were collected and analyzed to determine how the data compares to NASA’s pre-existing requirements from the cable/harness standards NASA-STD-8739.4 and IPC/WHMA-A-620B-S. The measured tensile strength of most of the contact/conductor pairs (i.e. Contact/Wires or C/W) exceeded the minimum pull force values of NASA-STD-8739.4 and IPC/WHMA-A-620 standards by at least 100 %. The tensile strength samples of the C/W pairs values followed a normal distribution with an average tensile strength value that was at least 182 % of the minimum requirement, and all the samples analyzed passed the pull force testing. In addition, the 95 % confidence interval of the average tensile strength distributions for several C/W pairs was determined and plotted as error bars to show that there is good likelihood to observe C/W pair normal distribution with a 95 % confidence interval that will meet and surpass the standard requirements. The frequency of pull force testing can be problematic for projects because of the cost and availability of spare contacts for the destructive test. It could be possible to reduce the frequency of pull force testing if at the beginning of the production run, the conditions of the crimp tool and materials are verified, and the settings of the tool remain unchanged throughout the process. However, the project must evaluate the impact to risk from reducing the frequency of testing.

Crimped connections↗
NASA NTRS2026

Smart Process Planning for Automated Fiber Placement

Many industries, including aerospace, automotive, wind energy, maritime, and sporting goods, rely on strong, lightweight materials called composites. These materials are made by layering fibers, which can come in the form of narrow strips or wider sheets, and setting them in a polymer matrix. One of the most advanced ways to make these parts is through automated fiber placement, where a machine lays down the fibers in precise patterns. This method can create very efficient and strong designs, but it is complex, expensive, and often depends heavily on the experience of skilled engineers. Today, the design, manufacturing, and inspection stages of composite production are usually handled separately. This separation means that important information, such as how a part will be built or what defects might occur, is not always shared between stages. As a result, parts may not be as lightweight, strong, or defect-free as possible, and the process can take longer and cost more. This research develops a smart process planning system that connects design, manufacturing, and inspection into one continuous process. Built as software that works with existing tools, the system can automatically plan how the fibers are placed, predicting and reducing defects while improving both manufacturability and strength. The system optimizes not only individual layers but also how defects are distributed across all layers, preventing them from stacking up in ways that weaken the final part. It also uses inspection results from completed parts to improve future designs, creating a feedback loop where each stage informs the others. The system was tested by designing a composite panel using this new approach and comparing it to a panel made with state-of-the-art manual planning methods. The results showed that the system could intentionally control where defects appeared and increase the efficiency of the planning process. By unifying design, manufacturing, and inspection, this research shows a way to make advanced composite manufacturing more efficient, consistent, and cost-effective. This approach lowers the barrier to using automated fiber placement and opens the door for its wider adoption not only in aerospace but also in industries such as automotive, wind energy, maritime, and sporting goods, where strong and lightweight structures are essential.

Computer-Aided Process Planning↗
NASA NTRS2004

STS Derived Exploration Launch Operations

A key aspect of the new space exploration programs will be the approach to optimize launch operations. A STS Derived Launch Vehicle (SDLV) Program can provide a cost effective, low risk, and logical step to launch all of the elements of the exploration program. Many benefits can be gained by utilizing the synergy of a common launch site as an exploration spaceport as well as evolving the resources of the current Space Shuttle Program (SSP) to meet the challenges of the Vision for Space Exploration. In particular, the launch operation resources of the SSP can be transitioned to the exploration program and combined with the operations efficiencies of unmanned EELVs to obtain the best of both worlds, resulting in lean launch operations for crew and cargo missions of the exploration program. The SDLV Program would then not only capture the extensive human space flight launch operations knowledge, but also provide for the safe fly-out of the SSP through continuity of system critical skills, manufacturing infrastructure, and ability to maintain and attract critical skill personnel. Thus, a SDLV Program can smoothly transition resources from the SSP and meet the transportation needs to continue the voyage of discovery of the space exploration program.

Best, Joel↗
NASA NTRS2000

WSTF Pyrovalve Test Program Status: 2000

Extensive propulsion and pyrotechnic testing has been in progress at NASA/JSC White Sands Test Facility (WSTF) since 1995, starting with the Mars Observer Propulsion and Pyrotechnics Corrective Action Test Program (MOCATP). The MOCATP has been concluded, but extensive pyrovalve testing plus research and development continues at WSTF. Our capability to accurately characterize pyrovalve combustion product blow-by into propellant systems, evaluate hydrazine and monomethylhydrazine (MMH) thermal decomposition initiated by blow-by, and characterize valve actuation operation, continues to be used and refined. Data from this and several low blow-by pyrovalves manufactured by Conax and other corporations continues to be evaluated as a potential corrective measure for blow-by induced propellant explosions. Additionally, new measurement techniques are being developed, advanced pyrovalve development is under-way, and nondestructive examination (NDE) methods are being developed to help ensure pyrovalve safety. Starting in 2000 these data are being formatted into a pyrovalve application and testing handbook. Near-term testing includes evaluation of 3/8-in. Conax pyrovalves and other commercially available valves; development of advanced pyrovalve subcomponent technology; investigation of NDE techniques to evaluate pyrovalve ram seals and real-time measurement of housing deformation; and investigation of pyrotechnically induced explosive hydrazine decomposition both through testing and modeling. Evaluation of 3/8-in. Conax valves is to include operational margin testing to be accomplished at the NASA Langley Research Center.

Saulsberry, Regor L.↗
NASA NTRSDate not supplied

NASA's Office Safety Mission Assurance Efforts to Improve Non-destructive Evaluation Methods for Additive Manufacturing and In-Space Inspection

National Aeronautics and Space Administration (NASA) continues to push the boundary of manned flight. Current mission profiles include flights to the Moon and Mars. Many of these missions require advance manufacturing and planned off planet resource utilization. As NASA continues to develop highly advance materials and manufacturing techniques to meet these mission profiles, inspection of these increasingly complex parts has had to evolve as well. Additive manufacturing is coming to the forefront as a primary manufacturing technique but offers unique challenges when inspection and certification are required. NASA has been working diligently to be a leader in developing and utilizing inspection techniques capable of inspecting these highly advanced parts. Additionally additive manufacturing techniques can also be used to build parts in space and provides a vehicle for in-situ resource utilization for off world missions. As NASA and its commercial crew partners move forward, inspection techniques will need to continue to advance to ensure safe manned space flight. In this talk NASA will highlight many of the advanced nondestructive evaluation efforts going on across the agency, as well as providing highlights for points of infusion for helping NASA meet its future mission goals.

NDE↗
NASA NTRS1982

Fabrication of advanced composites

Fabrication techniques for manufacturing advanced composite structures with continuous and short filaments in desired orientations and consolidation within the plies of the structure are described and analyzed. Attention is given to vacuum bag molding, autoclave molding, matched die consolidation of B/Al, B/epoxy, and graphite/epoxy composites, matched die molding of chopped fiber prepregs, thermal expansion molding, braiding, filament winding, sandwich fabrication, and pultrusions. Step-by-step preparation of resin-matrix composites is detailed, including automatic and semiautomatic lay-ups, and problems of quality control are discussed. The review is intended as an engineering aid for choices between competitive designs, and comprises factors other than technical features alone, such as cost effectiveness, ease of inspection, and economics of maintenance.

Meade, L. E. R.↗
NASA NTRS1990

Intelligent processing of intermetallic composite consolidation

Intermetallic composites based upon titanium aluminide matrices and silicon carbide of aluminum oxide fibers are emerging candidates for future hypersonic vehicle airframes and engines. To tailor the properties of these 'engineered' materials for specific application, to increase process yield, and to reduce costs, 'intelligent processing of materials' (IPM) control strategies are being explored for their processing. Recent progress is evaluated in the development of predictive process models, advanced sensors and control methodologies (the components of the IPM approach) for the critical near net-shape consolidation process step of continuous fiber reinforced intermetallic composite manufacture.

Wadley, H. N. G.↗
NASA NTRS1993

Orbiter lessons learned: A guide to future vehicle development

Topics addressed are: (1) wind persistence loads methodology; (2) emphasize supportability in design of reusable vehicles; (3) design for robustness; (4) improved aerodynamic environment prediction methods for complex vehicles; (5) automated integration of aerothermal, manufacturing, and structures analysis; (6) continued electronic documentation of structural design and analysis; and (7) landing gear rollout load simulations.

Greenberg, Harry Stan↗
NASA NTRS1999

Mars Observer Propulsion and Pyrotechnics Corrective Actions Test Program Status-1999

An extensive propulsion and pyrotechnic test program has been in progress at the NASA White Sands Test Facility since 1995. This program created the capabilities to: accurately measure and characterize pyrovalve combustion product blow-by into propellant systems; characterize valve operation using a Velocity Interferometer System for Any Reflector (VISAR); and evaluate hydrazine and monomethylhydrazine thermal decomposition initiated by blow-by. These capabilities were further utilized and refined this year. Low blow-by pyrovalves manufactured by Conax Florida Corporation continued to be evaluated as a potential corrective measure for blow-by induced propellant explosions. Development and testing of various advanced pyrovalves and investigation of explosion mechanisms also continued. Current and near-term testing includes: evaluation of 3/8 in. Conax pyrovalves and other commercially available valves; development and testing of advanced pyrovalve subcomponent technologies including a zero blow-by pyrovalve ram, composite overwrapped ram cylinder, and a zero particulate generating poppet; investigation of non-destructive evaluation techniques to evaluate pyrovalve ram seals; and testing and modeling of pyrotechnically induced explosive hydrazine decomposition. Evaluation of 3/8 in. Conax valves will include operational margin testing to be accomplished at NASA Langley Research Center. The test program also seeks to compile and format significant amounts of data from this and other pyrovalve test programs to generate a pyrovalve applications handbook. The handbook will facilitate formation of standards that ensure safe spacecraft applications. Current data and future plans are discussed, and community interaction is encouraged.

Saulsberry, Regor↗