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All sourcesNASA NTRSDOE OSTI
NASA NTRS2018

Chapter 6: Materials for Spacecraft

The general knowledge in this chapter is intended for a broad variety of spacecraft: manned or unmanned, low Earth to geosynchronous orbit, cis-lunar, lunar, planetary, or deep space exploration. Materials for launch vehicles are covered in chapter 7. Materials used in the fabrication of spacecraft hardware should be selected by considering the operational requirements for the particular application and the design engineering properties of the candidate materials. The information provided in this chapter is not intended to replace an in-depth materials study but rather to make the spacecraft designer aware of the challenges for various types of materials and some lessons learned from more than 50 years of spaceflight. This chapter discusses the damaging effects of the space environment on various materials and what has been successfully used in the past or what may be used for a more robust design. The material categories covered are structural, thermal control for on-orbit and re-entry, shielding against radiation and meteoroid/space debris impact, optics, solar arrays, lubricants, seals, and adhesives. Spacecraft components not directly exposed to space must still meet certain requirements, particularly for manned spacecraft where toxicity and flammability are concerns. Requirements such as fracture control and contamination control are examined, with additional suggestions for manufacturability. It is important to remember that the actual hardware must be tested to understand the real, "as-built" performance, as it could vary from the design intent. Early material trades can overestimate benefits and underestimate costs. An example of this was using graphite/epoxy composite in the International Space Station science racks to save weight. By the time the requirements for vibration isolation, Space Shuttle frequencies, and experiment operations were included, the weight savings had evaporated.

Finckenor, Miria M.↗
NASA NTRSDate not supplied

Solar Absorptivity Degradation of Spacecraft Materials Due to UV and Charged Particles in the Gateway Environment

Traditionally, most of the data accumulated for material optical property degradation in space has been in the Low Earth Orbit (LEO) environment. However, Gateway is a new space station that will be assembled and flown in Near Rectilinear Halo Orbit (NRHO) for 15 years. Additionally, some Gateway modules will have a slow transit from Earth to NRHO that will take over a year to pass through the Van Allen Belts, which contain damaging charged particles. The environments Gateway modules will encounter are not well characterized. Environmental factors such as charged particles and ultraviolet (UV) radiation have been shown to significantly increase solar absorptivity (α) for some thermal control materials and coatings. Since α will impact thermal performance over the mission, the Gateway Passive Thermal Control System (PTCS) Group has identified charged particle and UV degradation of Gateway materials as a knowledge gap. Candidate materials and coatings were subjected to expected mission charged particle environments and over 5000 Equivalent Solar Hours (ESH) of UV at NASA Goddard Space Flight Center (GSFC). In situ change in reflectivity was observed at specified intervals during testing such that change in α could be plotted as a function of time of solar exposure.

Optical Property↗
DOE OSTI2020

Design and Fabrication of the Mu2e Cryogenic Distribution System

The muon-to-electron conversion (Mu2e) experiment at Fermilab will be used to search for the charged lepton flavor-violating conversion of muons to electrons in the field of an atomic nucleus. The Mu2e experiment is currently in the design and construction stage and is expected to begin operations in 2022. The Mu2e experiment uses four large superconducting solenoid magnets including a Production Solenoid (PS), an Upstream and Downstream Transport Solenoid (TSu and TSd) and a Detector Solenoid (DS). This paper will focus on the cryogenic distribution system for these four solenoid magnets. Liquid helium will be supplied from two re-purposed Tevatron satellite refrigerators. A large cryogenic distribution box (DB) is located in the Mu2e building to distribute the required cryogens to each of the four solenoid magnets. Each solenoid magnet will have a dedicated transfer line and cryogenic feed box (FB). The solenoid magnets each require two liquid helium circuits and two liquid nitrogen circuits. The most unique feature about this cryogenic system is that the assemblies for the start of the superconducting portion of the power leads are mounted in feed boxes that are in the range of 23 m to 31 m away from the solenoid magnets. The cryogenic feed boxes are located remotely to provide protection from radiation damage and high magnetic fields. The power leads are NbTi superconducting cable stabilized with high conductivity aluminum. The 6061-T6 aluminum grade was selected for the transfer line piping so that the piping would thermally contract at the same rate as the power lead. A major concern for this transfer line is that a small helium leak could create an electric discharge arc due to the Paschen effect. This paper includes a description of the design features and testing done to ensure that the power leads are protected from the Paschen effect while still being adequately cooled to liquid helium temperatures.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Direct Observation of Tungsten Oxidation Studied by In Situ Environmental TEM

In this study, in situ environmental transmission electron microscopy (ETEM) was applied, for the first time, to investigate the thermal oxidation of a pristine and a self-ion irradiated polycrystalline tungsten, using a MEMS-based gas cell at 500 oC to 900 oC in a 1 bar 2%O2/N2 gas mixture. By tracking the dynamic evolution of the tungsten oxide scale as it initiates, grows, and sublimates during a consecutive thermal oxidation experiment, we observed two distinctive tungsten oxide microstructure – one nanocrystalline o-WO3 scale grown on W{27-1 } and W{1-1 8} and another o-WO3 scale exhibits a novel highly textured nanostructure. While the two oxide microstructures shared a similar thickness of ~200 nm after 40-minute early-stage oxidation, the nanocrystalline scale on the W{27-1 } grew much more rapidly at 800 oC than the highly textured oxide at a higher temperature of 900 oC. This suggests both the microstructure of these tungsten oxide scales as well as their oxidation kinetics are highly sensitive to the tungsten surface orientation, and such correlations also change dynamically in the course of oxidation. We also discuss the tungsten oxidation mechanism, the effects of the TEM foil thickness, and the focused ion beam (FIB) Ga+ damage on in situ ETEM oxidation.

In situ ETEM, Tungsten, Thermal oxidation, Orienta↗
NASA NTRS1989

Thermal barrier coating life prediction model development, phase 1

The objective of this program was to establish a methodology to predict thermal barrier coating (TBC) life on gas turbine engine components. The approach involved experimental life measurement coupled with analytical modeling of relevant degradation modes. Evaluation of experimental and flight service components indicate the predominant failure mode to be thermomechanical spallation of the ceramic coating layer resulting from propagation of a dominant near interface crack. Examination of fractionally exposed specimens indicated that dominant crack formation results from progressive structural damage in the form of subcritical microcrack link-up. Tests conducted to isolate important life drivers have shown MCrAlY oxidation to significantly affect the rate of damage accumulation. Mechanical property testing has shown the plasma deposited ceramic to exhibit a non-linear stress-strain response, creep and fatigue. The fatigue based life prediction model developed accounts for the unusual ceramic behavior and also incorporates an experimentally determined oxide rate model. The model predicts the growth of this oxide scale to influence the intensity of the mechanic driving force, resulting from cyclic strains and stresses caused by thermally induced and externally imposed mechanical loads.

Demasi, Jeanine T.↗
DOE OSTI2022

Synchrotron X-ray-induced Synthesis of Copper Hydroxide Nitrate Nanoplates on Cu Thin Films in an Ambient Atmosphere

Synchrotron X-rays are widely used for material characterizations. However, they can also ionize atoms and molecules to damage and manipulate probed materials. We report here an X-ray-induced growth of copper hydroxide nitrate, Cu 2 (OH) 3 NO 3 , on copper thin films in the ambient atmosphere without solvents and thermal treatment. In situ synchrotron X-ray diffraction measurements showed that the time-dependent growth process of the Cu 2 (OH) 3 NO 3 is accompanied by the consumption of Cu metal and can be described by a sigmoidal model. The growth rate was reduced after the initial fast growth period. Scanning electron microscopy (SEM) images show that the isolated islands of Cu 2 (OH) 3 NO 3 nanoplates formed in the beginning, which grew together with new nanoplates formed under continued X-ray irradiation. The result demonstrated that high-flux synchrotron X-rays may provide an unconventional approach to synthesizing and manipulating materials, which will inspire future investigation both experimentally and theoretically.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

2020 LANL Contributions to the BATS Test in WIPP

The DOE Office of Nuclear Energy (DOE-NE) repository research and development program seeks to provide a sound technical basis for multiple viable disposal options, increase confidence in the robustness of generic disposal concepts, and develop science and engineering tools needed to support disposal concept implementation. Sandia, Los Alamos, and Lawrence Berkeley National labs are conducting research into salt, which includes the Brine Availability Test in Salt (BATS) field test at the Waste Isolation Pilot Plant (WIPP), a DOE Office of Environmental Management facility. BATS is leveraging the existing infrastructure associated with the WIPP to advance science informing generic disposal concepts. BATS is an ongoing heated borehole experiment being conducted in the WIPP underground. The goal of this experiment is to reduce the uncertainty associated with spent nuclear fuel disposition in geologic salt formations. The BATS experiments is designed to accomplish this by increasing our understanding of brine migration in salt, assessing damaged zones from mining and drilling, simulating a post-closure environment, confirming salt properties, and providing data for model validation. Phased testing for generic salt repository R&D was proposed in 2015. Subsequently, borehole thermal testing was developed as a first step in this process. This document summarizes the work conducted on the BATS experiment during fiscal year 2020 with an emphasis on the contributions by Los Alamos National Lab.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Finite Element Simulation of the Acoustic Pressure Inside a Beverage Container for Non-Thermal, Ultrasound-based Pasteurization

The purpose of this effort is to investigate whether large acoustic pressure waves can be transmitted inside beverage containers to enable pasteurization. Acoustic waves are known to induce large nonlinear compressive forces and shock waves in fluids, suggesting that compression waves may be capable of damaging bacteria inside beverage containers without appreciably increasingly the temperature or altering the freshness and flavor of the beverage contents. Although a combined process such as thermosonication (e.g., sonication with heating) is likely more efficient, it is instructive to compute the acoustic pressure field distribution inside the beverage container. The COMSOL simulations used two and three-dimensional models of beverage containers placed in a water bath to compute the acoustic pressure field. A limitation of these COMSOL models is that they cannot determine the bacterial lysis efficiency, rather the models provide an indirect metric of bacterial lysis based on the magnitude of the pressure field and its distribution.

42 ENGINEERING↗
NASA NTRS1974

Heat-transfer thermal switch

Thermal switch maintains temperature of planetary lander, within definite range, by transferring heat. Switch produces relatively large stroke and force, uses minimum electrical power, is lightweight, is vapor pressure actuated, and withstands sterilization temperatures without damage.

Friedell, M. V.↗
NASA NTRS1982

The swing to concentrator arrays

Objectives and progress in both low concentration ratio (6 to 10) and high concentration ratio ( 100) array developments are summarized. Problems encountered include: thermal control, maldistribution of concentrated sunlight, current busing, and optical surface degradation. The potential advantages over planar arrays are an order of magnitude reduction in per unit cost of power plus increased immunity to radiation damage.

Miller, J. L.↗
NASA NTRS1984

Atomic-oxygen stimulated outgassing (A0034)

The objective of this experiment is to determine if the impingement of atomic oxygen in near-Earth orbit is a major factor in producing optically damaging outgassed products. The expected results will be to obtain samples which have been exposed to atomic oxygen for long durations. Analysis of these samples will determine if the impingement of atomic oxygen on the thermal control surfaces stimulates a significant amount of outgassed products. This experiment will give a clearer picture of the contamination problem and will assist in assuring that future Shuttle payloads, such as the Space Telescope and High-Energy Astronomy Observatory, will not experience Skylab contamination levels. Selected thermal control surfaces will be exposed to the atomic oxygen in near-Earth orbit. Passive collecting samples will collect any induced outgassing resulting from oxygen impingement. The optical condition of the passive samples will be measured using a ground-based integrating sphere reflectometer and a directional reflectometer.

Scott, R. L., Jr.↗
NASA NTRS1993

Sensitivity of dual-wall structures under hypervelocity impact to multi-layer thermal insulation thickness and placement

Results are presented from an experimental study in which Al dual-wall structures were tested, under various high-speed impact conditions, with a view to the effect of multilayer insulation thickness and location on perforation resistance. Attention is given to comparisons of the damage sustained by dual-wall systems with multilayer insulation blankets of various thicknesses and at various locations within the dual-wall system, under comparable impact loading conditions. The placement of the insulation has a significant effect on the ballistic limit of the dual-wall structures considered, while reducing insulation thickness by as much as a third did not.

Schonberg, William P.↗
NASA NTRS1991

NASA airframe structural integrity program

NASA has initiated a research program with the long-term objective of supporting the aerospace industry in addressing issues related to the aging commercial transport fleet. The interdisciplinary program combines advanced fatigue crack growth prediction methodology with innovative nondestructive examination technology with the focus on multi-site damage (MSD) at riveted connections. A fracture mechanics evaluation of the concept of pressure proof testing the fuselage to screen for MSD has been completed. Also, a successful laboratory demonstration of the ability of the thermal flux method to detect disbonds at riveted lap splice joints has been conducted. All long-term program elements have been initiated and the plans for the methodology verification program are being coordinated with the airframe manufacturers.

Harris, Charles E.↗
NASA NTRS1993

Effect of mission cycling on the fatigue performance of SiC-coated carbon-carbon composites

The effects of thermal and pressure cycling on the fatigue performance of carbon-carbon composites, and the influence of mission cycling on these effects, were investigated by subjecting both virgin and mission-cycled two-dimensional specimens of SiC-coated carbon-carbon composites to fatigue tests, conducted at room temperature in three-point bending, with a stress ratio of 0.2 and a frequency of 1 Hz. It was found that the fatigue strength of C-C composites is high (about 90 percent of the ultimate flexural strength), but decreased with the mission cycling. The lowering of the fatigue strength with mission cycling is attributed to the increase in interfacial bond strength due to thermal and pressure cycling of the material. The already high sensitivity of C-C composites to stress during cyclic loading increases further with the amount of mission cycling. Results of NDE suggest that the damage growth in virgin C-C, in the high-cycle range, is slow at the initial stage of the cyclic life, but propagates rapidly after certain threshold cycles of the fatigue life.

Mahfuz, H.↗
NASA NTRS2005

Lifetime Reliability Prediction of Ceramic Structures Under Transient Thermomechanical Loads

An analytical methodology is developed to predict the probability of survival (reliability) of ceramic components subjected to harsh thermomechanical loads that can vary with time (transient reliability analysis). This capability enables more accurate prediction of ceramic component integrity against fracture in situations such as turbine startup and shutdown, operational vibrations, atmospheric reentry, or other rapid heating or cooling situations (thermal shock). The transient reliability analysis methodology developed herein incorporates the following features: fast-fracture transient analysis (reliability analysis without slow crack growth, SCG); transient analysis with SCG (reliability analysis with time-dependent damage due to SCG); a computationally efficient algorithm to compute the reliability for components subjected to repeated transient loading (block loading); cyclic fatigue modeling using a combined SCG and Walker fatigue law; proof testing for transient loads; and Weibull and fatigue parameters that are allowed to vary with temperature or time. Component-to-component variation in strength (stochastic strength response) is accounted for with the Weibull distribution, and either the principle of independent action or the Batdorf theory is used to predict the effect of multiaxial stresses on reliability. The reliability analysis can be performed either as a function of the component surface (for surface-distributed flaws) or component volume (for volume-distributed flaws). The transient reliability analysis capability has been added to the NASA CARES/ Life (Ceramic Analysis and Reliability Evaluation of Structures/Life) code. CARES/Life was also updated to interface with commercially available finite element analysis software, such as ANSYS, when used to model the effects of transient load histories. Examples are provided to demonstrate the features of the methodology as implemented in the CARES/Life program.

Nemeth, Noel N.↗
NASA NTRS2009

Improved Fabrication of Ceramic Matrix Composite/Foam Core Integrated Structures

The use of hybridized carbon/silicon carbide (C/SiC) fabric to reinforce ceramic matrix composite face sheets and the integration of such face sheets with a foam core creates a sandwich structure capable of withstanding high-heatflux environments (150 W/cm2) in which the core provides a temperature drop of 1,000 C between the surface and the back face without cracking or delamination of the structure. The composite face sheet exhibits a bilinear response, which results from the SiC matrix not being cracked on fabrication. In addition, the structure exhibits damage tolerance under impact with projectiles, showing no penetration to the back face sheet. These attributes make the composite ideal for leading edge structures and control surfaces in aerospace vehicles, as well as for acreage thermal protection systems and in high-temperature, lightweight stiffened structures. By tailoring the coefficient of thermal expansion (CTE) of a carbon fiber containing ceramic matrix composite (CMC) face sheet to match that of a ceramic foam core, the face sheet and the core can be integrally fabricated without any delamination. Carbon and SiC are woven together in the reinforcing fabric. Integral densification of the CMC and the foam core is accomplished with chemical vapor deposition, eliminating the need for bond-line adhesive. This means there is no need to separately fabricate the core and the face sheet, or to bond the two elements together, risking edge delamination during use. Fibers of two or more types are woven together on a loom. The carbon and ceramic fibers are pulled into the same pick location during the weaving process. Tow spacing may be varied to accommodate the increased volume of the combined fiber tows while maintaining a target fiber volume fraction in the composite. Foam pore size, strut thickness, and ratio of face sheet to core thickness can be used to tailor thermal and mechanical properties. The anticipated CTE for the hybridized composite is managed by the choice of constituents, varying fiber tow sizes and constituent part ratios. This structural concept provides high strength and stiffness at low density 1.06 g/cm3 in panels tested. Varieties of face sheet constructions are possible, including variations in fiber type and weave geometry. The integrated structures possible with this composite could eliminate the need for non-load-bearing thermal protection systems on top of a structural component. The back sheet can readily be integrated to substructures through the incorporation of ribs. This would eliminate weight and cost for aerospace missions.

Hurwitz, Frances I.↗
NASA NTRS2015

NASA CPAS Drogue Textile Riser Feasibility Study

Steel cable was chosen for the lower end of the drogue and main parachute risers on NASA's Orion Multi Purpose Crew Vehicle Parachute Assembly System (CPAS) to protect the risers from extreme temperatures and abrasion should they contact the crew module during deployment, as was done for Apollo. Due to the weight and deployment complexity inherent in steel, there was significant interest in the possibility of substituting textile for steel for the drogue and main parachute risers. However, textile risers could be damaged when subjected to high temperature and abrasion. Investigations were consequently performed by a subset of the authors to determine whether sacrificial, non-load-bearing textile riser covers could be developed to mitigate the thermal and abrasion concerns. Multiple material combinations were tested, resulting in a cover design capable of protecting the riser against severe riser/crew module contact interactions. A feasibility study was then conducted to evaluate the performance of the textile drogue riser cover in relevant abrasive environments. This paper describes the testing performed and documents the results of this feasibility study.

Hennings, Elsa J.↗