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Hypervelocity Impact Characterization on Hubble Space Telescope Multi-Layer Insulation

Multi-layer insulation (MLI) is a common material used on rocket bodies and spacecraft to provide thermal regulation. This material is typically attached on the surface of the object in orbit and is thus exposed to the space environment and to micrometeoroid and orbital debris (MMOD) impacts. Occasionally, these exposed surfaces are returned and used by NASA’s Orbital Debris Program Office (ODPO) for analysis. When used to assess impacts on surfaces over time, materials like MLI provide an opportunity for in situ measurements to support the Orbital Debris Engineering Model (ORDEM) development and validation. During the 2009 Hubble Space Telescope (HST) Serving Mission, the MLI blankets covering the HST electronics bays 5, 8, and 10 were removed and subsequently analyzed by the ODPO in 2010. The bay 5 blanket was used in concert with ground-based hypervelocity impact tests on single layer MLI to validate the ORDEM 3.1 computer model of the OD environment, but further research was required to properly differentiate the impact features attributed to MM or OD. The ORDEM 3.1 validation effort identified several areas of further study to improve model validation and understanding of the space environment. Among these topics are the effects of underlying MLI layers on first layer impact feature characteristics, the effects of space weathering and associated damage to the surface on impact feature characteristics, and the transition from perforating to cratering regions. To better understand hypervelocity impact damage and long-term degradation of MLI surfaces, further hypervelocity impact testing was proposed and completed from 2020 to 2022. This paper discusses test conditions and parameters with resultant impact hole analyses of single layer versus multi-layered samples, space-exposed samples versus pristine, equivalent samples, and perforation versus cratering criteria in the difficult transition region. Damage equations, with associated uncertainties, are estimated from the test parameters and presented. The results of a feasibility study are described, in which the Scanning Electron Microscopy/Electron Dispersive X-ray was used to examine the MLI layers to differentiate MM and OD impacts. Finally, the extension of HST MLI outcomes and analysis methodology as it applies to future returned MLI samples is discussed.

Melissa A. Murray↗

NASA NTRS2023

Hypervelocity Impact Characterization on Hubble Space Telescope Multi-Layer Insulation

Multi-layer insulation (MLI) is a common material used on rocket bodies and spacecraft to provide thermal regulation. This material is typically attached on the surface of the object in orbit and is thus exposed to the space environment and to micrometeoroid and orbital debris (MMOD) impacts. Occasionally, these exposed surfaces are returned and used by NASA’s Orbital Debris Program Office (ODPO) for analysis. When used to assess impacts on surfaces over time, materials like MLI provide an opportunity for in-situ measurements to support the Orbital Debris Engineering Model (ORDEM) development and validation. During the 2009 Hubble Space Telescope (HST) Serving Mission, the MLI blankets covering the HST electronics bays 5, 8, and 10 were removed and subsequently analyzed by the ODPO in 2010. The bay 5 blanket was used in concert with ground-based hypervelocity impact tests on single layer MLI to validate the ORDEM 3.1 computer model of the OD environment, but further research was required to properly differentiate the impact features attributed to MM or OD. The ORDEM 3.1 validation effort identified several areas of further study to improve model validation and understanding of the space environment. Among these topics are the effects of underlying MLI layers on first layer impact feature characteristics, the effects of space weathering and associated damage to the surface on impact feature characteristics, and the transition from perforating to cratering regions. To better understand hypervelocity impact damage and long-term degradation of MLI surfaces, further hypervelocity impact testing was proposed and completed from 2020 to 2022. This paper discusses test conditions and parameters with resultant impact hole analyses of single layer versus multi-layered samples, space-exposed samples versus pristine, equivalent samples, and perforation versus cratering criteria in the difficult transition region. Damage equations, with associated uncertainties, are estimated from the test parameters and presented. The results of a feasibility study are described, in which the scanning electron microscopy/electron dispersive x-ray was used to examine the MLI layers to differentiate MM and OD impacts. Finally, the extension of HST MLI outcomes and analysis methodology as it applies to future returned MLI samples is discussed.

Melissa A Murray↗

NASA NTRS2019

Development of a Novel Helmet Support Assembly for NASA Orion Crew Survival Suit

Orion Spacecraft water landing environments have necessitated the design and testing of a novel Helmet Support Assembly (HSA) as part of the NASA Orion Crew Survival Systems (OCSS) launch and re-entry spacesuit. A series of development sled tests using 5 th female, 50th male, and 95th male Hybrid III Anthropometric Test Devices (ATDs) simulated worst case water landings and identified the need for an integrated suit countermeasure to control the helmet during dynamic loading. Initial prototype countermeasures rigidly restrained the helmet keeping the helmet in place as desired, but led to large force and moment transmission to the upper neck. Further development led to a flexible HSA which used high-strength steel wire contoured to the size-matched ATD thorax and attached to both the front and rear of the neck ring. The selected wire diameter and contoured shape provided some ability to flex under the expected worst-case dynamic loads. The existing shoulder harness was used to restrain the helmet motion during “eyeballs out/down” loading while also attempting to prevent head-to-helmet contact in “eyeballs down” spinal-axis loading. A new small prototype helmet was also developed and tested for the 5th and 50th ATDs with both HSA devices. Dynamic impact tests were conducted on the HIA (Horizontal Impulse Accelerator) at Wright Patterson Air Force Base (WPAFB) under simulated off-nominal landing conditions using a representative Orion seat and 5-point harness. For each ATD size, peak Neck Injury Criteria (Nij) were compared to equivalent sled tests with an unsuited ATD configuration. Adding a helmet without attempting to control motion increased peak Nij values for all ATD sizes. The use of the rigid countermeasure showed decreased peak Nij results for the 5th female, but increased peak Nij values for both 50th configurations and the 95th male ATDs. By comparison, the flexible HSA showed reduced peak Nij values for all ATD sizes. Overall, this series of dynamic impact tests identified a risk of increased crew neck loading when under- or over-restraining the helmet during simulated Orion water landings and also demonstrated an effective strategy to mitigate those loads with a compliant HSA design.

Safety↗

NASA NTRS2000

Ultrasonic Assessment of Impact-Induced Damage and Microcracking in Polymer Matrix Composites

The main objective of this NASA FAR project is to conduct ultrasonic assessment of impact-induced damage and microcracking in polymer matrix composites at various temperatures. It is believed that the proposed study of impact damage assessment on polymer matrix composites will benefit several NASA's missions and current interests, such as ballistic impact testing of composite fan containment and high strain rate deformation modeling of polymer matrix composites. Currently, impact-induced delamination and fracture in 6061-T6 aluminum/cast acrylic sandwich plates adhered by epoxy were generated in an instrumented drop-weight impact machine. Although only a small dent was produced on the aluminum side when a hemispherical penetrator tup was dropped onto it from a couple of inches, a large ring of delamination at the interface was observed. The delamination damage was often accompanied by severe shattering in the acrylic substratum. Damage patterns in the acrylic layer include radial and ring cracks and, together with delamination at the interface, may cause peeling-off of acrylic material from the sandwich plate. Theory of stress-wave propagation can be used to explain these damage patterns. The impact tests were conducted at various temperatures. The results also show clearly that temperature effect is very important in impact damage. For pure cast acrylic nil-ductile transition (NDT) occurs between 185-195 F Excessive impact energy was dissipated into fracture energy when tested at temperature below this range or through plastic deformation when tested at temperature above the NDT temperature. Results from this study will be used as baseline data for studying fiber-metal laminates, such as GLARE and ARALL for advanced aeronautical and astronautical applications.

Liaw, Benjamin↗

NASA NTRS2011

Response of Honeycomb Core Sandwich Panel with Minimum Gage GFRP Face-Sheets to Compression Loading After Impact

A compression after impact study has been conducted to determine the residual strength of three sandwich panel constructions with two types of thin glass fiber reinforced polymer face-sheets and two hexagonal honeycomb Nomex core densities. Impact testing is conducted to first determine the characteristics of damage resulting from various impact energy levels. Two modes of failure are found during compression after impact tests with the density of the core precipitating the failure mode present for a given specimen. A finite element analysis is presented for prediction of the residual compressive strength of the impacted specimens. The analysis includes progressive damage modeling in the face-sheets. Preliminary analysis results were similar to the experimental results; however, a higher fidelity core material model is expected to improve the correlation.

McQuigg, Thomas D.↗

DOE OSTI2018

Effect of the Combined Addition of Y and Ti on the Second Phase and Mechanical Properties of China Low-Activation Martensitic Steel

In this study, approximately 0.35% Ti and two different Y contents were added to China low-activation martensitic (CLAM) steel during melting in a vacuum induction melting furnace. Scanning electron microscopy, transmission electron microscopy, x-ray diffraction, tensile tests, and Charpy impact tests were used to investigate the effects of the combined addition of Y and Ti on the second phase and mechanical properties. The results indicated that Y and Fe formed the large intermetallic compound Fe-Y; the compound easily aggregated in the grain boundaries and exhibited the strength of CLAM steel. Ti did not combine with Y to form the Y-Ti-O phase; however, it could combine with Ta and W to form MC precipitates, which were generally in the 20-50 nm size range. The CLAM steel with a higher Y content exhibited lower yield and tensile strengths at room temperature, with both steels yielding almost identical strengths at 600 °C.

36 MATERIALS SCIENCE↗

DOE OSTI2011

Impact Plate Test Problem

The key objective of the proposed test problem (TP) is to verify Staggered Grid Hydrocodes (SGH) for metal impact with elastic collision and evaluate slide treatment as well as advection schemes.Our objective is to perform hydro computations of the flyer plate impact until t=3.00 μs.

42 ENGINEERING↗

NASA NTRS1984

Photovoltaic module encapsulation design and materials section, volume 2

Tests for chemical structure, material properties, water absorption, aging and curing agent of Ethylene Vinyl Acetate (EVA) and UV absorption studies are carried out. A computer model was developed for thermal optical modeling, to investigate dependence between module operating temperature and solar insolation, and heat dissapation behavior. Structural analyses were performed in order to determine the stress distribution under wind and heat conditions. Curves are shown for thermal loading conditions. An electrical isolation was carried out to investigate electrical stress aging of non-metallic encapsulation materials and limiting material flaws, and to develop a computer model of electrical fields and stresses in encapsulation materials. In addition, a mathematical model was developed and tests were conducted to predict hygroscopic and thermal expansion and contraction on a plastic coated wooden substrate. Thermal cycle and humidity freezing cycle tests, partial discharge tests, and hail impact tests were also carried out. Finally, the effects of soiling on the surface of photovoltaic modules were investigated. Two antisoiling coatings, a fluorinated silane and perflourodecanoic acid were considered.

Cuddihy, E. F.↗

NASA NTRS1984

Relationship between phase difference and coefficient of restitution during low velocity foreign object transverse damage of composite plates

This work discusses a model to correlate the coefficient of restitution of low velocity transverse impacts of graphite-epoxy laminates with the residual deformation or central deflection at the end of the impact event. It is assumed that the energy absorbed by the target can be calibrated in terms of residual deflection, and thereby in terms of phase difference between the occurrence of impact force and central deflection to their maximas. Analysis was modeled on the basis of the experience from impact tests. Predictions are compared with the test results of impacted circular and flat plates. Experimentally measured values of coefficient of restitution and phase difference agreed well with the predicted relationship between them.

Lal, K. M.↗

NASA NTRS1990

Cross-sectional examination of the damage zone in impacted specimens of carbon/epoxy and carbon/PEEK composites

Drop weight impact testing was utilized to inflict damage on eight-ply bidirectional and unidirectional samples of carbon/epoxy and carbon/PEEK (polyetheretherketone) test specimens with impact energies ranging from 0.80 J to 1.76 J. The impacting tip was of a smaller diameter (4.2-mm) than those used in most previous studies, and the specimens were placed with a diamond wheel wafering saw through the impacted area perpendicular to the outer fibers. Photographs at 12 x magnification were taken of these cross-sections and examined. The results on the bidirectional samples show little damage until 1.13 J, at which point delaminations were seen in the epoxy specimens. The PEEK specimens showed less delamination than the epoxy specimens for a given impact energy level. The unidirectional specimens displayed more damage than the bidirectional samples for a given impact energy, with the PEEK specimens showing much less damage than the epoxy material.

Nettles, A. T.↗

NASA NTRS1990

Fractography of composite delamination

The microdamage that occurs for Mode 1 and Mode 2 delamination was examined by potting delaminated specimens in a clear epoxy, sectioning through the damage, polishing the cut sections and examining using light microscopy. For Mode 1 delamination of unidirectional carbon fiber reinforced plastic (CFRP) composites, the major observation was fiber bridging including large ligaments of fiber bundles. The Mode 2 delamination of unidirectional laminates revealed a very narrow crack opening with only occasional fiber bridging. Impact testing by repetitive impacts with increasing energy was studied and it was found that this technique does not discern changes in the type of damage with increasing cumulative impact energy. Instead, the changes in the impact response, notably stiffness, are the result of changes in the extent of damage. For laminates with a brittle thermoplastic matrix, 3501-6, there were distinct changes in stiffness that corresponded to the development of through the thickness damage and then to the extension of the damage to the specimen edges. For PEEK and polycarbonate, the changes in stiffness were not as abrupt as for the thermoset. None the less, the damage progressed in the same manner.

Bascom, W. D.↗

NASA NTRS2003

Thermal Management Coating As Thermal Protection System for Space Transportation System

This paper presents viewgraphs on the development of a non-ablative thermal management coating used as the thermal protection system material for space shuttle rocket boosters and other launch vehicles. The topics include: 1) Coating Study; 2) Aerothermal Testing; 3) Preconditioning Environments; 4) Test Observations; 5) Lightning Strike Test Panel; 6) Test Panel After Impact Testing; 7) Thermal Testing; and 8) Mechanical Testing.

Kaul, Raj↗

NASA NTRS1978

Impact behavior of filament-wound graphite/epoxy fan blades

The fabrication and impact tests of graphite/epoxy filament wound fan blades are discussed. Blades which were spin tested at tip speeds up to 305 m/sec retained their structural integrity. Two blades were each impacted with a 454-g slice of a 908-g simulated bird at a tip speed of 263 deg and impact angles of 22 deg and 32 deg. The impact tests were recorded with high-speed movie film. The blade which was impacted at 22 deg sustained some root delamination but remained intact. The 32 deg impact separated the blade from the root. No local damage other than leading-edge debonding was observed for either blade. The results of a failure mode analysis are also discussed.

Bowles, K. J.↗

NASA NTRS2017

A Comparison of the SOCIT and DebriSat Experiments

This paper explores the differences between, and shares the lessons learned from, two hypervelocity impact experiments critical to the update of orbital debris environment models. The procedures and processes of the fourth Satellite Orbital Debris Characterization Impact Test (SOCIT) were analyzed and related to the ongoing DebriSat experiment. SOCIT was the first hypervelocity impact test designed specifically for satellites in Low Earth Orbit (LEO). It targeted a 1960's U.S. Navy satellite, from which data was obtained to update pre-existing NASA and DOD breakup models. DebriSat is a comprehensive update to these satellite breakup models- necessary since the material composition and design of satellites have evolved from the time of SOCIT. Specifically, DebriSat utilized carbon fiber, a composite not commonly used in satellites during the construction of the US Navy Transit satellite used in SOCIT. Although DebriSat is an ongoing activity, multiple points of difference are drawn between the two projects. Significantly, the hypervelocity tests were conducted with two distinct satellite models and test configurations, including projectile and chamber layout. While both hypervelocity tests utilized soft catch systems to minimize fragment damage to its post-impact shape, SOCIT only covered 65% of the projected area surrounding the satellite, whereas, DebriSat was completely surrounded cross-range and downrange by the foam panels to more completely collect fragments. Furthermore, utilizing lessons learned from SOCIT, DebriSat's post-impact processing varies in methodology (i.e., fragment collection, measurement, and characterization). For example, fragment sizes were manually determined during the SOCIT experiment, while DebriSat utilizes automated imaging systems for measuring fragments, maximizing repeatability while minimizing the potential for human error. In addition to exploring these variations in methodologies and processes, this paper also presents the challenges DebriSat has encountered thus far and how they were addressed. Accomplishing DebriSat's goal of collecting 90% of the debris, which constitutes well over 100,000 fragments, required addressing many challenges stemming from the very large number of fragments. One of these challenges arose in identifying the foam-embedded fragments. DebriSat addressed this by X-raying all of the panels once the loose debris were removed, and applying a detection algorithm developed in-house to automate the embedded fragment identification process. It is easy to see how the amount of data being compiled would be outstanding. Creating an efficient way to catalog each fragment, as well as archiving the data for reproducibility also posed a great challenge for DebriSat. Barcodes to label each fragment were introduced with the foresight that once the characterization process began, the datasheet for each fragment would have to be accessed again quickly and efficiently. The DebriSat experiment has benefited significantly by leveraging lessons learned from the SOCIT experiment along with the technological advancements that have occurred during the time between the experiments. The two experiments represent two ages of satellite technology and, together, demonstrate the continuous efforts to improve the experimental techniques for fragmentation debris characterization.

Ausay, Erick↗

NASA NTRS2016

IADC Vulnerability Report, IT32-13

This section provides hypervelocity impact test data for two types of batteries: Lithium-Ion (Li-Ion) and Nickel Hydrogen (Ni-H2) batteries. The impact tests were directed by the NASA Johnson Space Center Hypervelocity Impact Technology (HVIT) group in Houston Texas, and were performed at the NASA White Sands Test Facility (WSTF).

Christiansen, E. L.↗

NASA NTRS1991

Demonstration of Hazardous Hypervelocity Test Capability

NASA Johnson Space Center (JSC) White Sands Test Facility (WSTF) participated in a joint test program with NASA JSC Hypervelocity Impact Research Laboratory (HIRL) to determine if JSC was capable of performing hypervelocity impact tests on hazardous targets. Seven pressurized vessels were evaluated under hypervelocity impact conditions. The vessels were tested with various combinations of liquids and gasses at various pressures. Results from the evaluation showed that vessels containing 100-percent pressurized gas sustained more severe damage and had a higher potential for damaging nearby equipment, than vessels containing 75-percent liquid, 25-percent inert pressurized gas. Two water-filled test vessels, one of which was placed behind an aluminum shield, failed by bulging and splitting open at the impact point; pressure was relieved without the vessel fragmenting or sustaining internal damage. An additional water-filled test vessel, placed a greater distance behind an aluminum shield, sustained damage that resembled a shotgun blast, but did not bulge or split open; again, pressure was relieved without the vessel fragmenting. Two test vessels containing volatile liquids (nitro methane and hydrazine) also failed by bulging and splitting open; neither liquid detonated under hypervelocity test conditions. A test vessel containing nitrogen gas failed by relieving pressure through a circular entry hole; multiple small penetrations opposite the point of entry provided high velocity target debris to surrounding objects. A high-pressure oxygen test vessel fragmented upon impact; the ensuing fire and high velocity fragments caused secondary damage to surrounding objects. The results from the evaluation of the pressurized vessels indicated that JSC is capable of performing hypervelocity impact tests on hazardous targets.

Rodriquez, Karen M.↗

NASA NTRS2011

Design of Spacecraft Missions to Test Kinetic Impact for Asteroid Deflection

There are currently over 8,000 known near-Earth asteroids (NEAs), and more are being discovered on a continual basis. More than 1,200 of these are classified as Potentially Hazardous Asteroids (PHAs) because their Minimum Orbit Intersection Distance (MOID) with Earth's orbit is <= 0.05 AU and their estimated diameters are >= 150 m. To date, 178 Earth impact structures have been discovered, indicating that our planet has previously been struck with devastating force by NEAs and will be struck again. Such collisions are aperiodic events and can occur at any time. A variety of techniques have been proposed to defend our planet from NEA impacts by deflecting the incoming asteroid. However, none of these techniques have been tested. Unless rigorous testing is conducted to produce reliable asteroid deflection systems, we will be forced to deploy completely untested -- and therefore unreliable -- deflection missions when a sizable asteroid on a collision course with Earth is discovered. Such missions will have a high probability of failure. We propose to address this problem with a campaign of deflection technology test missions deployed to harmless NEAs. The objective of these missions is to safely evaluate and refine the mission concepts and asteroid deflection system designs. Our current research focuses on the kinetic impactor, one of the simplest proposed asteroid deflection techniques in which a spacecraft is sent to collide with an asteroid at high relative velocity. By deploying test missions in the near future, we can characterize the performance of this deflection technique and resolve any problems inherent to its execution before needing to rely upon it during a true emergency. In this paper we present the methodology and results of our survey, including lists of NEAs for which safe and effective kinetic impactor test missions may be conducted within the next decade. Full mission designs are also presented for the NEAs which offer the best mission opportunities.

Hernandez, Sonia↗

DOE OSTI2023

Deep learning-enhanced design for functionally graded auxetic lattices

Auxetic materials with counterintuitive negative Poisson’s ratio have been of significant interest due to potential applications across diverse engineering fields. Functionally grading such auxetics further enables customization of the structural response and harnesses the potential for multi-functional applications. However, a critical challenge in designing functionally graded lattices is to efficiently determine the spatial variation of the functional gradient and the corresponding geometric designs to achieve the desired response. In this paper, a highly efficient deep learning-based inverse design framework for functionally graded tetra-petal auxetics with spatially tailored properties is presented. This framework significantly improves the efficiency of tailoring functionally graded auxetics where many unit cells need to be tailor-designed. The graded tetra-petal auxetics obtained from the inverse design framework are additively manufactured and subjected to impact tests. The results show superior impact performance compared with uniform designs, demonstrating the effectiveness of the proposed inverse design framework, which can be inspirable to promote advanced structures/materials with enhanced impact resistance.

42 ENGINEERING↗