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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 1,459 records · Page 81
All sourcesNASA NTRSDOE OSTI
NASA NTRS2019

Analysis of Bioreduction Strategies for a Solid Rocket Motor on an Interplanetary Mission to Europa

The Europa Lander De-Orbit stage braking motor must comply with the Planetary Protection requirements established for a category IV mission. In its mission to Europa, a motor that hasn’t gone through bioreduction environments will carry microbial spores and other biosignature molecules that might jeopardize a mission of astrobiological concern as well as future missions to come. A motor with solid rocket propellant represents exclusive challenges associated to the calculation of high numbers of an encapsulated bioburden hidden behind a nozzle plug. Existing techniques for bioburden reduction are analysed in perspective to motor assembly facilities and the series of events that are involved in manufacturing a solid rocket motor. These techniques include antimicrobial effects of chemical components already present within the motor and bioreduction due to assembly and operational environments induced in the motor. Analysis of the manufacturing process, adhered bioburden and recent investigations into the effectiveness of microbiological techniques in finding inherent antimicrobial properties have generated a step by step outline of Planetary Protection for lander mission associated solid rocket motors.

Velez-Justiniano, Yo-Ann↗
NASA NTRS2019

Heat-Cleaned Nextel in MMOD Shielding

Meteoroid and orbital debris (MMOD) shielding can include NextelTM ceramic cloth in the outer layers of the shielding to enhance MMOD breakup. The Nextel fabric can contain size (or sizing) which aids in manufacture of the fabric. Sizing is a starch, oil or waxy material that is added to the rovings and yarns to protect the fibers from being cut or broken during the fabric manufacturing process and by later handling. For spacecraft applications, sizing is removed by heat-cleaning to reduce/eliminate off-gassing during vacuum operations. After the sizing is removed, the fibers in the woven fabric are prone to breakage during handling which reduces fabric strength. Because heat-cleaned Nextel tends to shed fibers that can be irritating to workers, the usual practice for hypervelocity impact tests is to use Nextel with sizing. The reduced strength of heat-cleaned Nextel does not typically effect the performance of MMOD shields with Nextel used in outer layers of the shield, because the density and areal density of the ceramic fibers in the fabric control MMOD breakup (not fabric strength). This paper provides data demonstrating that hypervelocity impact protection performance is not adversely altered for shields containing heat-cleaned Nextel compared to Nextel with sizing.

Christiansen, Eric L.↗
NASA NTRS2018

Effectiveness of Surface Treatment Techniques for Composite Bonding with Different Contamination Levels

Various surface treatment techniques have been developed to promote adhesive bond performance for composite structural components in aerospace applications. The condition of the pre-bond surface is critical to achieving desirable bond quality. Contamination on bonding surfaces is well recognized as a major threat to ultimate bond performance. Variation in contamination level has brought additional challenges into manufacturing process control. High fidelity surface treatment techniques are required for effective removal of contaminants over a wide range of contamination levels. In this study, a common contaminant, i.e. silicone mold release, was introduced to pre-bond composite surfaces with different concentrations. Plasma and laser surface treatment techniques were performed and their effectiveness in restoring and enhancing desirable bond quality was investigated. Surface characterization techniques, including water contact angle goniometry, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, were conducted to assess the condition of contaminated surfaces and the improvement induced by plasma and laser surface treatments. Failure modes from a customized double cantilever beam test were investigated before and after surface treatments. Fundamental mechanisms of plasma and laser surface treatments on the composite bonding surfaces were also investigated.

Fang, Xiaomei↗
NASA NTRS2012

TPSAS-NF1676L-13555-DND

A sub-scale advanced composite shell design is evaluated to determine its potential for use on a future aircraft fuselage. Two composite shells with the same nominal 8-ply [?45/?]s layup are evaluated, where ? indicates a tow-steered ply. To build this shell, a fiber placement machine is used to steer unidirectional prepreg tows as they are placed around the circumference of a 17-inch diameter right circular cylinder. The fiber orientation angle varies continuously from 10 degrees (with respect to the shell axis of revolution) at the crown, to 45 degrees on the side, and back to 10 degrees on the keel. All 24 tows are placed at each point on every fiber path in one structure designated as the shell with overlaps. The resulting pattern of tow overlaps causes the laminate thickness to vary between 8 and 16 plies. The second shell without tow overlaps uses the capability of the fiber placement machine to cut and add tows at any point along the fiber paths to fabricate a shell with a nearly uniform 8-ply laminate thickness. Static stiffness and buckling loads of shells with tow-steered layups are compared with the performance of a baseline quasi-isotropic shell using both finite element analyses and classical strength of materials theory. These tailored, tow-steered shells were then were designed and built at the National Center for Advanced Manufacturing - Louisiana Partnership under a joint NASA-industry collaborative effort. The shells were fabricated from unidirectional IM7/8552 graphite-epoxy pre-preg slit tape material placed on a constant-diameter mandrel. An overview of the detailed design and manufacturing processes for these shells is presented, and issues encountered during their design, analysis, fabrication and post-cure evaluation are presented and discussed. Future plans for structural testing and analyses of the shells are also discussed.

K Chauncey Wu↗
NASA NTRSDate not supplied

NASA's Space Launch System Progress Toward the Launch Pad

NASA’s Space Launch System (SLS) took a substantial step toward the launch site in2020 with the move of the Artemis I core stage from the manufacturing site to the test stand as the program plans for a 2021 launch. (Fig. 1) SLS is NASA’s evolvable super-heavy-lift launch vehicle to support deep space exploration. It is based on evolutionary improvement to existing proven propulsion systems. Its twin solid rocket boosters employ a five-segment motor based on the four-segment space shuttle motor. Its four RS-25 main engines will operate at thrust levels higher than those in the space shuttle program. The core stage is anew design that will support propellant tanks for the engines and serve as the attach point for the boosters. Modern streamlined manufacturing processes and materials have been incorporated into the initial configuration with planned onramps for improved performance and/or affordability in subsequent versions. The primary role of SLS is to anchor the transportation for NASA’s Artemis Program to return humans to the Moon and build on the exploration that began during the Apollo Program. This paper will discuss progress to date for the SLS Program and look ahead to important milestones in 2020 and beyond.

John H Honeycutt↗
NASA NTRSDate not supplied

Electrodynamic Dust Shield Testing on the Materials on International Space Station Experiment 11

Dust is a major concern for lunar exploration. To combat the effects of dust, NASA, academia, and industry are developing solutions to the dust problem. One potential technology solution for this problem is the Electrodynamic Dust Shield (EDS). Many years of research and development have gone into this technology. The Materials on International Space Station Experiment – 11 (MISSE-11) provides a long term space exposure platform for this technology to verify compatibility of materials and manufacturing processes to the space environment. The MISSE-11 EDS experiment consists of 12 EDS panels. These panels are made of glass, polyimide, or prototype spacesuit fabric. Some panels are covered with a lotus leaf coating while others are covered with thermal paint. They are flown in the wake position of the ISS to simulate the lunar environment. Two panels are in an active configuration and are energized with a high voltage power supply, which generates high-voltage pulses to activate the dust shields. Current and voltage data are recovered from each of these trials to compare to baseline data. Also, each of the EDS panels are imaged on a monthly basis to track any changes with time that may occur with the EDS variants. In this paper, we report preliminary data and analysis from this spaceflight experiment.

Electrostatics↗
NASA NTRS2021

Various Types of Defects Detection in Flat and Curved Laminated Composite Plates using Nonintrusive Lamb Wave System

Composite materials are widely used in aerospace industries due to their light weight, strength, and various other desired properties. However, they are susceptible to various defects occurring during the manufacturing process or in service. Typical defects include porosity, wrinkles, and delamination. Nondestructive means of detection of the defects at any stage are of great importance to ensure quality and safety of composite structures. A nonintrusive removeable Lamb wave system and accompanied methodology that is not material-dependent is presented in this paper to detect various types of typical defects in laminated composite plates, flat or curved. Through multidimensional data acquisition and processing, abnormality in waves caused by defects is captured and presented in inspection images. The methodologies are demonstrated in 2 cases: flat plate with wrinkles, and curved plate with delamination. Overall the results show that Lamb waves using the piezoelectric transducer and laser vibrometer system can be used for various types of defects inspection in flat or curved composite plates.

composite structures↗
NASA NTRS2018

Development of Low-Scatter Optical Edges for Starshades

Starshades, combined with future space telescopes, provide the ability to detect Earth-like exoplanets in the habitable zone by producing high contrast ratios at small inner working angles. The primary function of a starshade is to suppress light from a target star such that its orbiting planets are revealed. In order to do so, the optical edges of the starshade must maintain their precise in-plane profile to produce the necessary apodization function. However, an equally important consideration is the interaction of these edges with light emanating from our own Sun as scattered and/or diffracted sunlight can significantly degrade the achievable contrast. This paper describes the technical efforts performed to obtain precision, low-scatter optical edges for future starshades. Trades between edge radius (i.e. sharpness) and surface reflectivity have been made and small-scale coupons have been produced using scalable manufacturing processes. A custom scattered light testbed has been developed to quantify the magnitude of scattered light over all sun angles. Models have also been developed to make predictions on the level of reflected and/or diffracted light for various edge architectures. The results of these studies have established a current baseline approach which implements photochemical etching techniques on thin metal foils.

Bradley, Christine↗
NASA NTRS2021

Hot Isostatic Pressing for Reduction of Defects in Additively Manufactured Inconel-718 Preliminary Simulation Approach and Results

Selective laser melting (SLM) of Inconel-718 (IN718) is a promising advanced manufacturing technology; however, challenges exist for fracture-critical parts where pores induced during the manufacturing process reduce fatigue life of the material. Hot isostatic pressing (HIP) is a common post processing technique used to reduce the part porosity by exposing parts to high temperature and pressures. Pore closure depends on the pore shape, trapped gas, and HIP parameters, and the process can only be optimized by understanding the effect of these variables. An analysis capability is described to better understand the conditions necessary for pore closure, and the effect of several variables on porosity are explored and compared to a baseline case. The importance of valid material response models is identified as a significant factor in model accuracy; especially the creep material response model which, in the baseline case, predicts that creep strain accounts for 87.7% of the total strain at the conclusion of the HIP cycle. Lessons learned are described, in addition to future work including model validation.

Joshua M Fody↗
NASA NTRSDate not supplied

Ceramic Heat Pipe for Thermal Management of a High Frequency Inductor

As the power density of electric machines and power electronics continues to increase to meet the demands of more electric aircraft, the thermal management of these devices becomes increasingly important. Ideally, the thermal management solution of the device should have high thermal conductivity and be electrically insulating so that it can be directly integrated with the device in question. Technical ceramics are a class of materials that meet these two requirements. Direct liquid cooling by submerging electric components in a dielectric fluid is an alternate option, but adds system complexity and may incur pumping loss. In this work, the thermal management solution for a high frequency inductor is presented. A conventional wicked heat pipe is designed that is made from a solid ceramic case with a sintered ceramic wick. This heat pipe can provide structural support for the core and windings and is electrically insulating, so it does not incur any additional eddy current losses from the high frequency magnetic fields. It does not require additional pumping power, because conventional wicked heat pipes are passive devices. In this paper, the manufacturing process of the ceramic heat pipe is also presented. It is shown that the sintering of large diameter spherical ceramic particles is difficult due to their high specific surface area and low surface free energy. To overcome this difficulty, a flux material was used to initiate liquid phase sintering. The results of the sintering trials show that for the 120 μm diameter α-Al2O3powder selected for the wick, the combination of 1650°C sintering temperature and the addition of 5 wt% talc sintered the porous matrix together sufficiently for use as a heat pipe wic

High-frequency Inductor↗
NASA NTRSDate not supplied

Ceramic Heat Pipe for Thermal Management of a High Frequency Inductor

As the power density of electric machines and power electronics continues to increase to meet the demands of more electric aircraft, the thermal management of these devices becomes increasingly important. Ideally, the thermal management solution of the device should have high thermal conductivity and be electrically insulating so that it can be directly integrated with the device in question. Technical ceramics are a class of materials that meet these two requirements. Direct liquid cooling by submerging electric components in a dielectric fluid is an alternate option, but adds system complexity and may incur pumping loss. In this work, the thermal management solution for a high frequency inductor is presented. A conventional wicked heat pipe is designed that is made from a solid ceramic case with a sintered ceramic wick. This heat pipe can provide structural support for the core and windings and is electrically insulating, so it does not incur any additional eddy current losses from the high frequency magnetic fields. It does not require additional pumping power, because conventional wicked heat pipes are passive devices. In this paper, the manufacturing process of the ceramic heat pipe is also presented. It is shown that the sintering of large diameter spherical ceramic particles is difficult due to their high specific surface area and low surface free energy. To overcome this difficulty, a flux material was used to initiate liquid phase sintering. The results of the sintering trials show that for the 120 μm diameter α-Al2O3 powder selected for the wick, the combination of 1650°C sintering temperature and the addition of 5 wt% talc sintered the porous matrix together sufficiently for use as a heat pipe wick.

High frequency inductor↗
NASA NTRS2022

Laser Patterning Assisted Devitrification and Domain Engineering of Amorphous and Nanocrystalline Alloys

We have investigated laser-patterning and devitrification as a novel method to realize emergent properties in modified regions at the ribbon surface consisting of periodic localized laser spots thermally treated under rapid heating and cooling conditions. Fe-based amorphous ribbons were annealed for systematically varied laser power. Extremely high heating and cooling rates on the order of 10(exp 8)-10(exp 10)K/s have been estimated by finite element analysis simulations. Observations suggest surface melting followed by rapid solidification fast enough to quench and form an amorphous structure upon cooling. Diffusion of heat occurs from the laser irradiated surface region so that a finite volume of material surrounding this region rises in temperature above the crystallization temperature relevant for conventional isothermal annealing experiments. The underlying mechanism of laser annealing and consequences of heat transients involved are discussed in terms of impacts upon micro/nanostructure, residual stresses, and magnetic domain structure surrounding the laser irradiated region. The study illustrates the potential to exploit spatially optimized phase transformations in a scalable manufacturing process of amorphous and nanocrystalline alloys to locally access otherwise inaccessible extreme heating and cooling rates.

Amorphous ribbons↗
NASA NTRSDate not supplied

Microbes Share Rides Too: Updating Encapsulated Bioburden Estimate Values in Electronic Parts Common to Class D Mission Platforms.

As NASA develops more planetary protection missions that are Category III and in the Class D/rideshare mission platform, there is an increasing reliance on estimation of prelaunch bioburden to understand needs for burn up and breakup analyses or other methods to meet pre-launch bioburden levels. Current levels estimated for the encapsulated bioburden of semiconductor parts cited by NASA have been based on estimates of semiconductor manufacturing approaches from the 1970s that do not incorporate over fifty years of evolving cleanliness of semiconductor manufacturing processes and facilities. This investigation will focus on direct sampling of semiconductor parts for encapsulated bioburden values, drawing upon Goddard’s strength in EEE parts, supply chain management, destructive parts analysis and existing local planetary protection lab facilities to prepare and measure encapsulated bioburden at a statistically significant level for standard electronics parts common to known Class D/rideshare platforms.

planetary protection↗
NASA NTRSDate not supplied

Metallic Vs Inflatable Primary Structure: A Comprehensive Trade for a Mars Transit Habitat

Large diameter inflatable habitat solutions are hypothesized to have an advantage over traditional metallic habitats of equal volume and functional requirements in terms of minimizing mass. A fair and comprehensive trade of metallic primary structure versus inflatable softgoods primary structure for a Mars Transit Habitat was conducted by The Boeing Company under the NASA Next Space Technologies for Exploration Partnerships-2 (NextSTEP-2)Appendix A contract in order to determine the minimum mass option from a system level. A Mars Transit Habitat is a major system mass driver because small increases in the mass can create large mass changes in the propulsive stage, adding complexity and cost to the mission. Three different vehicle configurations were traded using a fixed volume constraint and the same Ground Rules and Assumptions(GR&A)provided by NASA. The configurations were 1) 5.5 m diameter metallic habitat, 2) 7.0 m diameter metallic habitat, and 3) 7.63 m diameter inflatable habitat. In order to complete the trade, each configuration was analyzed and sized, but a system level approach had to be taken to ensure other aspects and subsystems besides the structure were captured. The primary functions (i.e. restraint layer, bladder, multilayer insulation [MLI], micro-meteoroid orbital debris [MMOD]) and strength advantages of softgoods are well understood, but there were other system level impacts that were discovered or addressed that are unique to softgoods. For the metallic structure, a modern and mass optimal material and manufacturing process was adopted to ensure the lightest weight options were evaluated. Two different aluminium lithium structures were evaluated, a longer length 5.5 m diameter and a shorter length 7 m diameter structure. The trade demonstrates that each configuration is feasible and close to the target dry mass for the Mars Transit Habitat Trans-Martian Injection burn. System level mass was the primary consideration, but since the three concepts were close in total mass, a clear winner did not arise. Secondary factors were evaluated such as architecture habitability (human factors), development considerations, on-orbit activation and outfitting, extensibility to other applications, and configuration flexibility. The aggregation of the lowest mass, most benefits, and fewest challenges resulted in the 5.5m diameter metallic configuration being the most favorable.

Matthew Ziglar↗
NASA NTRSDate not supplied

xPLSS Structural Backplate Design, Manufacture, and Test Overview

NASA Johnson Space Center (JSC) has been developing and building a new detailed design of the Exploration Extravehicular Mobility Unit (xEMU) space suit to support future International Space Station (ISS) and Lunar Artemis missions. The Exploration Portable Life Support System (xPLSS) of the xEMU contains some clever new technologies to meet the requirements to provide Extra Vehicular Activity (EVA) capability on the ISS and the Moon. The suit must interface with and fit through ports and airlocks of at least three vehicles: ISS, Human Landing System (HLS), and Gateway. The first partial xPLSS experimental flight unit called SWME EXPRESS Rack Flight Experiment (SERFE) that was a rack-deployed thermal control system payload on the ISS for two years (2020-2022). The first complete assembly of the xEMU was built as a Design Verification Test (DVT) unit (2022); similar to but more extensive than an Engineering Development Unit (EDU). The xPLSS Backplate serves not only as the structural backbone of the xPLSS and SERFE systems but also contains innovative design features to reduce the: mass, complexity, parts count, number ofseals (and therefore leak potential), and outer dimensions of the entire assembly. This paper provides an overview of these new design features, manufacturing processes, system interfaces, and SERFE/DVT test results of the Backplate as part of the xPLSS/xEMU.

xPLSS↗
NASA NTRS2022

Solid-State Ultracapacitor Polymer Composite

An ultracapacitor made from a polymer loaded with ceramic powder would have several advantages over current ultracapacitors and batteries. First is the possibility of it being printable, which would allow for printing the energy storage device along with the circuit instead of having to find a way to add one later without damaging the rest of the components. When not printed in a specific design for use on a printed wiring board, this type of ultracapacitor could still be cured via a mold to a shape suitable to specific applications. Many polymers maintain some flexibility even after curing, such as the silicone used in this study. The manufacturing process would also be far simpler than that of conventional ultracapacitors.In this work, solid-state ultracapacitors were made by adding the dielectric powder to a two-part polymer (resin and hardener) at the same time. The mixture was then cured in the desired shape at a low temperature until completely set. The addition of the powder to the polymer increased its dielectric properties while leaving most of its physical properties unaltered. At higher powder loading percentages, there were some physical changes as the maximum loading point was approached. To determine the efficiency of these solid-state ultracapacitors, their capacitances were tested, and their dielectric constants (DCs) were measured and compared.

energy storage↗
NASA NTRS2023

Guidelines for Screening, Lot Acceptance, and Derating for Polymer Tantalum Capacitors

These guidelines have been developed for NASA space projects that are planning to use new technology hermetic and chip polymer cathode tantalum capacitors. Polymer Tantalum Capacitors (PTC) selected from MIL-PRF-32700, automotive grade (AEC-Q200) parts, or COTS+ (hi-rel COTS) capacitors should be screened and qualified as suggested in Tables 1-3 and derated per section 9 below. Screening and lot acceptance tests that were carried out for a lot that is intended for flight as a part of the manufacturing process do not need to be repeated

tantalum capacitors↗