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All sourcesNASA NTRSDOE OSTI
NASA NTRS2013

Swamp Works- Multiple Projects

My Surface Systems internship over the summer 2013 session covered a broad range of projects that utilized multiple fields of engineering and technology. This internship included a project to create a command center for a 120 ton regolith bin, for the design and assembly of a blast shield to add further protection for the Surface Systems engineers, for the design and assembly of a portable four monitor hyper wall strip that could extend as large as needed, research and programming a nano drill that could be utilized on a next generation robot or rover, and social media tasks including the making of videos, posting to social networking websites and creation of a new outreach program to help spread the word about the Swamp Works laboratory.

Carelli, Jonathan M.↗
NASA NTRS2003

High-Frequency Testing of Composite Fan Vanes With Erosion-Resistant Coating Conducted

The mechanical integrity of hard, erosion-resistant coatings were tested using the Structural Dynamics Laboratory at the NASA Glenn Research Center. Under the guidance of Structural Mechanics and Dynamics Branch personnel, fixturing and test procedures were developed at Glenn to simulate engine vibratory conditions on coated polymer-matrix- composite bypass vanes using a slip table in the Structural Dynamics Laboratory. Results from the high-frequency mechanical bench testing, along with concurrent erosion testing of coupons and vanes, provided sufficient confidence to engine-endurance test similarly coated vane segments. The knowledge gained from this program will be applied to the development of oxidation- and erosion-resistant coatings for polymer matrix composite blades and vanes in future advanced turbine engines. Fan bypass vanes from the AE3007 (Rolls Royce America, Indianapolis, IN) gas turbine engine were coated by Engelhard (Windsor, CT) with compliant bond coatings and hard ceramic coatings. The coatings were developed collaboratively by Glenn and Allison Advanced Development Corporation (AADC)/Rolls Royce America through research sponsored by the High-Temperature Engine Materials Technology Project (HITEMP) and the Higher Operating Temperature Propulsion Components (HOTPC) project. High-cycle fatigue was performed through high-frequency vibratory testing on a shaker table. Vane resonant frequency modes were surveyed from 50 to 3000 Hz at input loads from 1g to 55g on both uncoated production vanes and vanes with the erosion-resistant coating. Vanes were instrumented with both lightweight accelerometers and strain gauges to establish resonance, mode shape, and strain amplitudes. Two high-frequency dwell conditions were chosen to excite two strain levels: one approaching the vane's maximum allowable design strain and another near the expected maximum strain during engine operation. Six specimens were tested per dwell condition. Pretest and posttest inspections were performed optically at up to 60 magnification and using a fluorescent-dye penetrant. Accumulation of 10 million cycles at a strain amplitude of two to three times that expected in the engine (approximately 670 Hz and 20g) led to the development of multiple cracks in the coating that were only detectable using fluorescent-dye penetrant inspection. Cracks were prevalent on the trailing edge and on the convex side of the midsection. No cracking or spalling was evident using standard optical inspection at up to 60 magnification. Further inspection may reveal whether these fine cracks penetrated the coating or were strictly on the surface. The dwell condition that simulated actual engine conditions produced no obvious surface flaws even after up to 80 million cycles had been accumulated at strain amplitudes produced at approximately 1500 Hz and 45g.

Bowman, Cheryl L.↗
NASA NTRS1996

Contamination control engineering design guidelines for the aerospace community

Thermal control surfaces, solar arrays, and optical devices may be adversely affected by a small quantity of molecular and/or particulate contamination. What is rarely discussed is how one: (1) quantifies the level of contamination that must be maintained in order for the system to function properly, and (2) enforces contamination control to ensure compliance with requirements. This document is designed to address these specific issues and is intended to serve as a handbook on contamination control for the reader, illustrating process and methodology while providing direction to more detailed references when needed. The effects of molecular contamination on reflecting and transmitting surfaces are examined and quantified in accordance with MIL STD 1246C. The generation, transportation, and deposition of molecular contamination is reviewed and specific examples are worked to illustrate the process a design engineer can use to estimate end of life cleanliness levels required by solar arrays, thermal control surfaces, and optical surfaces. A similar process is used to describe the effect of particulate contamination as related to percent area coverage (PAC) and bi-directional reflectance distribution function (BRDF). Relationships between PAC and surface cleanliness, which include the effects of submicron sized particles, are developed and BRDF is related to specific sensor design parameters such as Point Source Transmittance (PST). The pros and cons of various methods of preventing, monitoring, and cleaning surfaces are examined and discussed.

Tribble, A. C.↗
NASA NTRS1983

Comparison of seal materials for use in Stirling engines

In a dry, reciprocating sliding test, rods of 12 different surface materials rubbed against a glass filled PTFE gas seal. To simulate operation in a Stirling engine a gas (N2) pressure of 1 MPa differential pressure was applied across the seal. Gas leakage rates, rods surface temperatures, changes in the surface finish of the rod, surface hardness of the rod and wear rate of the seals were measured. The rod surface materials that produced the least seal were: plasma sprayed molybdenum (75 Mo 18 Ni 4 Cr), gas nitrided steel, and plasma sprayed aluminum oxide (94 Al2O3 6 TiO2). In contrast to almost all other mating surfaces, the surface roughness of the rods coated with Mo did not decrease during wear. This property is very important for the formation of a PTFE transfer film on the mating surface. The presence of a stable transfer film gives a low PTFE wear rate.

Lundholm, G.↗
NASA NTRS1975

Interior noise considerations for powered-lift STOL aircraft

Powered-lift configurations which are currently under development for future use on STOL aircraft involve impingement of the jet engine exhaust onto wing and flap surfaces. Previous studies have suggested that the impinging jet produces higher noise levels at lower frequencies than does the jet alone. These higher levels, together with the close proximity of the engine and flap noise sources to the fuselage sidewall, suggest that the noise levels in these aircraft may be high enough to interfere with passenger comfort. To investigate this possibility, interior noise levels were estimated for both an upper surface blown (USB) and an externally blown flap (EBF) configuration. This paper describes the procedure used to estimate the interior noise levels and compares these levels with levels on existing jet aircraft and on ground transportation vehicles. These estimates indicate high levels in the STOL aircraft; therefore, areas of possible improvements in technology for control of STOL interior noise are also discussed.

Barton, C. K.↗
NASA NTRS2015

Jet-Surface Interaction: High Aspect Ratio Nozzle Test, Nozzle Design and Preliminary Data

The Jet-Surface Interaction High Aspect Ratio (JSI-HAR) nozzle test is part of an ongoing effort to measure and predict the noise created when an aircraft engine exhausts close to an airframe surface. The JSI-HAR test is focused on parameters derived from the Turbo-electric Distributed Propulsion (TeDP) concept aircraft which include a high-aspect ratio mailslot exhaust nozzle, internal septa, and an aft deck. The size and mass flow rate limits of the test rig also limited the test nozzle to a 16:1 aspect ratio, half the approximately 32:1 on the TeDP concept. Also, unlike the aircraft, the test nozzle must transition from a single round duct on the High Flow Jet Exit Rig, located in the AeroAcoustic Propulsion Laboratory at the NASA Glenn Research Center, to the rectangular shape at the nozzle exit. A parametric nozzle design method was developed to design three low noise round-to-rectangular transitions, with 8:1, 12:1, and 16: aspect ratios, that minimizes flow separations and shocks while providing a flat flow profile at the nozzle exit. These designs validated using the WIND-US CFD code. A preliminary analysis of the test data shows that the actual flow profile is close to that predicted and that the noise results appear consistent with data from previous, smaller scale, tests. The JSI-HAR test is ongoing through October 2015. The results shown in the presentation are intended to provide an overview of the test and a first look at the preliminary results.

Aeroacoustics↗
NASA NTRS2023

NASA Advanced Space Suit Pressure Garment System Status 2023

This paper discusses the current focus of NASA’s Advanced Space Suit Pressure Garment Technology Development team’s efforts, the status of that work, and a summary of longer term technology development priorities and activities. The Exploration Extra-vehicular Activity Mobility Unit (xEMU) has been the team’s primary effort over the past several years. ICES papers in 2022 detailed the design of the xEMU pressure garment components. This paper outlines the design updates to the xPGS since that time. More notably, this paper documents the various tests executed with the xPGS to evaluate its performance, durability, and acceptability for microgravity and Lunar missions. An overview of ongoing and planned xEMU testing and training is provided. The PGS team’s transition from xEMU development and testing, to supporting the Exploration Extravehicular Activity Services (xEVAS) vendors will also be discussed. In addition, technology development efforts in coordination with the EVA and Human Surface Mobility Program (EHP), the NASA Engineering Safety Council (NESC) and the Small Business Innovation Research (SBIR) Program will be discussed in the context of supporting sustaining EVA operations on the Lunar surface over the coming decade. Finally, a brief review of longer-term pressure garment challenges and technology gaps will be presented to provide an understanding of the advanced pressure garment team’s technology investment priorities and needs.

spacesuit↗
NASA NTRSDate not supplied

NASA Advanced Space Suit Pressure Garment System Status and Development Priorities 2023

This paper discusses the current focus of NASA’s Advanced Space Suit Pressure Garment Technology Development team’s efforts, the status of that work, and a summary of longer term technology development priorities and activities. The Exploration Extra-vehicular Activity Mobility Unit (xEMU) has been the team’s primary effort over the past several years. ICES papers in 2022 detailed the design of the xEMU pressure garment components. This paper outlines the design updates to the xPGS since that time. More notably, this paper documents the various tests executed with the xPGS to evaluate its performance, durability, and acceptability for microgravity and Lunar missions. An overview of ongoing and planned xEMU testing and training is provided. The PGS team’s transition from xEMU development and testing, to supporting the Exploration Extravehicular Activity Services (xEVAS) vendors will also be discussed. In addition, technology development efforts in coordination with the EVA and Human Surface Mobility Program (EHP), the NASA Engineering Safety Council (NESC) and the Small Business Innovation Research (SBIR) Program will be discussed in the context of supporting sustaining EVA operations on the Lunar surface over the coming decade. Finally, a brief review of longer-term pressure garment challenges and technology gaps will be presented to provide an understanding of the advanced pressure garment team’s technology investment priorities and needs.

spacesuit↗
NASA NTRSDate not supplied

NASA Advanced Space Suit Pressure Garment System Status and Development Priorities 2023

This paper discusses the current focus of NASA’s Advanced Space Suit Pressure Garment Technology Development team’s efforts, the status of that work, and a summary of longer term technology development priorities and activities. The Exploration Extra-vehicular Activity Mobility Unit (xEMU) has been the team’s primary effort over the past several years. ICES papers in 2022 detailed the design of the xEMU pressure garment components. This paper outlines the design updates to the xPGS since that time. More notably, this paper documents the various tests executed with the xPGS to evaluate its performance, durability, and acceptability for microgravity and Lunar missions. An overview of ongoing and planned xEMU testing and training is provided. The PGS team’s transition from xEMU development and testing, to supporting the Exploration Extravehicular Activity Services (xEVAS) vendors is discussed. In addition, technology development efforts in coordination with the EVA and Human Surface Mobility Program (EHP), the NASA Engineering Safety Council (NESC) and the Small Business Innovation Research (SBIR) Program will be discussed in the context of supporting sustaining EVA operations on the Lunar surface over the coming decade. Finally, a brief review of longer-term pressure garment challenges and technology gaps will be presented to provide an understanding of the advanced pressure garment team’s technology investment priorities and needs.

spacesuit↗
NASA NTRSDate not supplied

NASA Advanced Space Suit Pressure Garment System Status and Development Priorities 2024

This paper discusses the current focus of NASA’s Advanced Space Suit Pressure Garment Technology Development team’s efforts, the status of that work, and a summary of longer term technology development priorities and activities. The Exploration Extra-vehicular Activity Mobility Unit (xEMU) has been the team’s primary effort over the past several years. This paper documents the various tests executed with the xPGS to evaluate its performance, durability, and acceptability for microgravity and Lunar missions. An overview of ongoing and planned xEMU testing and training is provided. The PGS team’s efforts in supporting the Exploration Extravehicular Activity Services (xEVAS) vendors is discussed. In addition, technology development efforts in coordination with the EVA and Human Surface Mobility Program (EHP), the NASA Engineering Safety Council (NESC) and the Small Business Innovation Research (SBIR) Program will be discussed in the context of supporting sustaining EVA operations on the Lunar surface over the coming decade. Finally, a brief review of longer-term pressure garment challenges and technology gaps will be presented to provide an understanding of the advanced pressure garment team’s technology investment priorities and needs.

Shane M McFarland↗
NASA NTRSDate not supplied

NASA Advanced Space Suit Pressure Garment System Status and Development Priorities 2024

This paper discusses the current focus of NASA’s Advanced Space Suit Pressure Garment Technology Development team’s efforts, the status of that work, and a summary of longer term technology development priorities and activities. The Exploration Extra-vehicular Activity Mobility Unit (xEMU) has been the team’s primary effort over the past several years. This paper documents the various tests executed with the xPGS to evaluate its performance, durability, and acceptability for microgravity and Lunar missions. An overview of ongoing and planned xEMU testing and training is provided. The PGS team’s efforts in supporting the Exploration Extravehicular Activity Services (xEVAS) vendors is discussed. In addition, technology development efforts in coordination with the EVA and Human Surface Mobility Program (EHP), the NASA Engineering Safety Council (NESC) and the Small Business Innovation Research (SBIR) Program will be discussed in the context of supporting sustaining EVA operations on the Lunar surface over the coming decade. Finally, a brief review of longer-term pressure garment challenges and technology gaps will be presented to provide an understanding of the advanced pressure garment team’s technology investment priorities and needs.

Shane McFarland↗
NASA NTRS1983

Fluctuating pressure measurements on the fan blades of a turbofan engine during ground and flight tests

As part of a program to investigate fan noise generated by a turbofan engine, miniature pressure transducers were used to measure the fluctuating pressures on the surface of a fan blade on the JT15D engine. Tests were conducted on the ground, with tunnel and in flight. Using narrowband spectra analysis and signal enhancement techniques, comparisons for these various test conditions are presented. Results on the blade pressures are also presented from a flight test in which 41 rods were placed in front of the fan face to excite a known spinning mode in the duct. Results showed that with care, ground tests can be conducted in which the pressure loading on the blades are similar to those in flight. Comparison of pressure transducers on the blade surface also showed that a single transducer would provide much of the information available from this type of measurement.

Schoenster, J. A.↗
NASA NTRS1976

Upper Surface Nacelle Influence on SCAR Aerodynamic Characteristics at Transonic Speeds

The arrow-wing transport configuration with detached engines located over the wing to produce upper surface exhaust flow effects was tested at angles of attack from -4 deg to 8 deg and jet total-pressure ratios from 1 (Jet off) to approximately 10. Wing tip leading edge flap deflections of -10 deg to 10 deg were tested with the wing-body configuration only (no nacelles). Tests were made with various nacelle chordwise, spanwise, and vertical height locations over the Mach number, angle of attack, and jet total-pressure ratio ranges. Deflecting the wing tip leading edge flap from 0 deg to -10 deg increased maximum lift to drag ratio by 1.0 at subsonic speeds. Installation of upper surface nacelles (no wing/nacelle pylons) increased the wing-body pitching moment at all Mach numbers and decreased the drag of the wing-body configuration at subsonic Mach numbers. Jet exhaust interference effects were negligible.

Mercer, C. E.↗
NASA NTRS2007

Continued Investigation of Leakage and Power Loss Test Results for Competing Turbine Engine Seals

Seal leakage decreases with increasing surface speed due to reduced clearances from disk centrifugal growth. Annular and labyrinth seal leakage are 2-3 times greater than brush and finger seal leakage. Seal leakage rates increase with increasing temperature because of seal clearance growth due to different coefficients of thermal expansion between the seal and test disk. Seal power loss is not strongly affected by inlet temperature. Seal power loss increases with increasing surface speed, seal pressure differential, mass flow rate or flow factor, and radial clearance. The brush and finger seals had nearly the same power loss. Annular and labyrinth seal power loss were higher than finger or brush seal power loss. The brush seal power loss was the lowest and 15-30% lower than annular and labyrinth seal power loss.

Delgado, Irebert R.↗
NASA NTRS2000

Erosion Coatings for High-Temperature Polymer Composites: A Collaborative Project With Allison Advanced Development Company

The advantages of replacing metals in aircraft turbine engines with high-temperature polymer matrix composites (PMC's) include weight savings accompanied by strength improvements, reduced part count, and lower manufacturing costs. Successfully integrating high-temperature PMC's into turbine engines requires several long-term characteristics. Resistance to surface erosion is one rarely reported property of PMC's in engine applications because PMC's are generally softer than metals and their erosion resistance suffers. Airflow rates in stationary turbine engine components typically exceed 2.3 kg/sec at elevated temperatures and pressures. In engine applications, as shown in the following photos, the survivability of PMC components is clearly a concern, especially when engine and component life-cycle requirements become longer. Although very few publications regarding the performance of erosion coatings on PMC's are available particularly in high-temperature applications the use of erosion-resistant coatings to significantly reduce wear on metallic substrates is well documented. In this study initiated by the NASA Glenn Research Center at Lewis Field, a low-cost (less than $140/kg) graphite-fiber-reinforced T650 35/PMR 15 sheet-molding compound was investigated with various coatings. This sheet-molding compound has been compression molded into many structurally complicated components, such as shrouds for gas turbine inlet housings and gearboxes. Erosion coatings developed for PMC s in this study consisted of a two-layered system: a bondcoat sprayed onto a cleaned PMC surface, followed by an erosion-resistant, hard topcoat sprayed onto the bondcoat as shown in following photomicrograph. Six erosion coating systems were evaluated for their ability to withstand harsh thermal cycles, erosion resistance (ASTM G76 83 "Standard Practice for Conducting Erosion Tests by Solid Particle Impingement Using Gas Jets") using Al2O3, and adhesion to the graphite fiber polyimide composite (ASTM D 4541 95 "Pull Off Strength of Coatings"). Glenn and Allison Advanced Development Company collaborated to optimize erosion coatings for gas turbine fan and compressor applications. All the coating systems survived aggressive thermal cycling without spalling. During erosion tests (see the final photo), the most promising coating systems tested had Cr3C2-NiCr and WC-Co as the hard topcoats. In all cases, these coating systems performed significantly better than that with a TiN hard topcoat. When material depth (thickness) loss is considered, the Cr3C2-NiCr and WC-Co coating systems provided, on average, an erosion resistance 8.5 times greater than that for the uncoated PMR 15/T650 35 composite. Similarly, Cr3C2-NiCr and WC-Co coating systems adhered to the PMC substrate during tensile tests significantly better than systems containing a TiN topcoat. Differences in topcoats of Cr3C2-NiCr and WC-Co were determined by considering issues such as cost and environmental impact. The preferred erosion-resistant coating system for PMR 15/T650 35 has WC-Co as the hard topcoat. This system provides the following benefits in comparison to the coating system with Cr3C2-NiCr topcoat: lower powder material cost (15 to 20 percent), environmentally friendly materials (Cr3C2-NiCr is hazardous), and higher deposition yield (10 to 15 percent), which results in less waste.

Sutter, James K.↗
DOE OSTI2024

Controlling cantilevered adaptive X-ray mirrors

Modeling the behavior of a prototype cantilevered X-ray adaptive mirror (held from one end) demonstrates its potential for use on high-performance X-ray beamlines. Similar adaptive mirrors are used on X-ray beamlines to compensate optical aberrations, control wavefronts and tune mirror focal distances at will. Controlled by 1D arrays of piezoceramic actuators, these glancing-incidence mirrors can provide nanometre-scale surface shape adjustment capabilities. However, significant engineering challenges remain for mounting them with low distortion and low environmental sensitivity. Finite-element analysis is used to predict the micron-scale full actuation surface shape from each channel and then linear modeling is applied to investigate the mirrors' ability to reach target profiles. Using either uniform or arbitrary spatial weighting, actuator voltages are optimized using a Moore–Penrose matrix inverse, or pseudoinverse, revealing a spatial dependence on the shape fitting with increasing fidelity farther from the mount.

47 OTHER INSTRUMENTATION↗
NASA NTRSDate not supplied

Recent Activities of the Marshall Space Flight Center Natural Environments Branch Terrestrial & Planetary Environments Team

- The Natural Environments (NE) Branch is within the MSFC Engineering Directorate’s Spacecraft and Vehicle System (S&VS) Department - S&VS plans, performs and directs the technical Design, Analysis, Test, Evaluation, Verification, Integration, and Applied Research and Development of future Spacecraft and Launch Vehicle Systems - Current programs we support - Space Launch System, Human Landing System, Mars Ascent Vehicle, Orion, Gateway - NE maintains expertise in terrestrial, space, and planetary natural environments definition, characterization, and analysis - Responsibility to disseminate this expertise to Agency programs and projects in support of environment definition, requirements development, vehicle development, operations, and sustaining engineering through program’s life cycle - Branch has two teams; Terrestrial and Planetary Environments (T&PE) and Space Environments (SE) - T&PE has extensive expertise characterizing terrestrial surface and atmospheric (aloft) environments - Winds, temperature, humidity, pressure, lightning, density, precipitation, radiant energy, aerosols, sea state, sea surface temperature - Maintains climatological databases for engineering analyses

Ryan K. Decker↗