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Results for “PENETRATING PARTICLE”

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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Impact behavior of graphite-epoxy simulated fan blades

The response of a graphite-epoxy material, Modmor II/PR-286, to foreign object impact was investigated by impacting spherical projectiles of three different materials - gelatin, ice, and steel - on simulated blade specimens. Visual and metallographic inspection revealed three damage mechanisms: penetration, leading edge bending failure, and stress wave delamination and cracking. The steel projectiles caused penetration damage regardless of the impact location and angle. For the ice and gelatin particles impacting the leading edge, failure was due to large local bending strains, resulting in significant material removal and delamination damage.

Cook, T. S.↗
NASA NTRS1980

Possible rim crest deposits in cores 12027 and 15008 - Some interpretations and problems for future research

Light colored coarse grained soils in the upper parts of cores 12027 and 15008 have a chaotic fabric and abundant bedrock-derived rock fragments. They overlie dark colored, fine grained soils with horizontal fabric and abundant regolith-derived rock fragments. The light colored soils are interpreted to be rim crest deposits associated with the craters seen in the lunar surface sampling photographs. The coarse size, poor sorting and chaotic fabric are believed to have originated by the violent mixing processes which are expected with ejecta deposition. The increase in bedrock-derived particles within the light colored soil can be explained by ejecta from craters that penetrated through or deep into the regolith. The dark soils are believed to predate the craters. Distribution of rock fragments in the material interpreted as rim crest ejecta does not fit a simple model of overturned stratigraphy.

Nagle, J. S.↗
NASA NTRS1990

Advanced meteoroid and debris shielding concepts

The results of the shielding screening and optimization work conducted at the NASA Johnson Space Center Hypervelocity Impact Research Laboratory (HIRL) are described. The impact tests to investigate and optimize certain aspects of the aluminum mesh double-bumper concept, which was considered the best performer in the screening test, are analyzed. Preliminary results indicate that the aluminum mesh double-bumper concept shows a 30 to 40 percent weight reduction compared to an aluminum Whipple shield in the velocity range study, besides such advantages as an increased resistance to penetration and the fact that the aluminum mesh does not produce damaging secondary ejecta particles. It is suggested that the ballistic protection can be improved even more if an intermediate layer of a high-strength cloth is attached near the rear wall.

Christiansen, Eric L.↗
NASA NTRS1994

Impact on comet Shoemaker-Levy 9 on Jupiter

Three-dimensional numerical simulations of the impact of Comet Shoemaker - Levy 9 on Jupiter and the resulting vapor plume expansion were conducted using the Smoothed Particle Hydrodynamics (SPH) method. An icy body with a diameter of 2 km can penetrate to an altitude of -350 km (0 km = 1 bar) and most of the incident kinetic energy is transferred to the atmosphere between -100 km to -250 km. This energy is converted to potential energy of the resulting gas plume. The unconfined plume expands vertically and has a peak radiative power approximately equal to the total radiation from Jupiter's disk. The plume rises a few tens of atmospheric scale heights in approximately 10(exp 2) seconds. The rising plume reaches the altitude of approximately 3000 km, but no atmospheric gas is accelerated to the escape velocity (approximately 60 km/s).

Ahrens, Thomas J.↗
NASA NTRS1994

Impact of comet Shoemaker-Levy 9 on Jupiter

We have employed three-dimensional numerical simulations of the impact of Comet Shoemaker-Levy 9 (SL9) on Jupiter and the resulting vapor plume expansion using the smoothed particle hydrodynamics (SPH) method. An icy body with a diameter of 2 km can penetrate to an altitude of -350 km (0 km = 1 bar) and most of the incident kinetic energy is transferred to the atmosphere between -100 to -250 km. This energy is converted to potential energy of the resulting gas plume. The unconfined plume expands vertically and has a peak radiative power approximately equal to the total radiation from Jupiter's disc. The plume rises a few tens of atmospheric scale heights in approximately 10(exp 2) seconds. The rising plume reaches the altitude of approximately 3000 km; however, no atmospheric gas is accelerated to the escape velocity (approximately 60 km/s).

Takata, Toshiko↗
NASA NTRS1999

International Space Station (ISS) Meteoroid/Orbital Debris Shielding

Design practices to provide protection for International Space Station (ISS) crew and critical equipment from meteoroid and orbital debris (M/OD) Impacts have been developed. Damage modes and failure criteria are defined for each spacecraft system. Hypervolocity Impact -1 - and analyses are used to develop ballistic limit equations (BLEs) for each exposed spacecraft system. BLEs define Impact particle sizes that result in threshold failure of a particular spacecraft system as a function of Impact velocity, angles and particle density. The BUMPER computer code Is used to determine the probability of no penetration (PNP) that falls the spacecraft shielding based on NASA standard meteoroid/debris models, a spacecraft geometry model, and the BLEs. BUMPER results are used to verify spacecraft shielding requirements Low-weight, high-performance shielding alternatives have been developed at the NASA Johnson Space Center (JSC) Hypervelocity Impact Technology Facility (HITF) to meet spacecraft protection requirements.

Christiansen, Eric L.↗
NASA NTRS2019

High Velocity Impact Performance of a Dual Layer Thermal Protection System for the Mars Sample Return Earth Entry Vehicle

The Mars Sample Return (MSR) Earth Entry Vehicle (EEV) is currently planned on being released from its Micro-Meteorite/Orbital Debri (MM/OD) shielding housing about two days before the Earth entry phase. This leaves the EEV exposed to incoming MM/OD impacts, potentially damaging the heat shield and compromising its Entry, Decent, and Landing (EDL) integrity. Currently, two materials are proposed to comprise the MSR-EEV heat shield, a dual layer material Heat-shield for Extreme Entry Environment Technology (HEEET) and Phenolic Impregnated Carbon Ablator (PICA). PICA has been well characterized for OD class impacts, ~7km/s high mass impacts, from previous testing done in the Orion program, but hasn't under-gone extensive MM impact testing. HEEET is a rela-tively new material with minimal prior testing in re-gards to High Velocity Impacts (HVI). In order to in-form selectability of a material, it is crucial to under-stand the material performance when faced with an HVI, directly affecting mission success probability.The current measure of a Thermal Protection Sys-tem's (TPS) performance against an HVI is evaluating a thermally sized material against its derived Balistic Limit Equation (BLE). A BLE is generated empirically from multiple shots of HVI testing, and is used as a first order method in evaluating TPS's performance against the expected MM/OD environment. This method has proved useful for previous uniform densi-ty TPS materials, but has never been validated against a dual layer recession material such as HEEET. Testing in the MSR program for FY19 has a re-quirement to assess the effects of a dual layer TPS by testing various thicknesses of HEEET's Recession Layer, seen in Figure 1. From this data, BLE's will be derived for the individual thickness ratio samples, as well as the material as a whole to evaluate if a heritage form of the BLE can capture the complex physics associated with a dual layer system. Crater morpholo-gy will also be assessed with post-test Non-Destructive Evaluation (NDE) methods such as CT scanning to visualize if a BLE can well predict the associated pene-tration depths, since a BLE assumes full disinigration of the impacting particle and is generally only used to size a spherical crater ? disregarding any shrapenel effects from a high density impactor.To inform this analysis, expected MM environ-ments from the Meteoroid Engineering Model (MEM) and analytical equations for mass flux of incoming MM were evaluated against the notional MSR-EEV trajectory [1]. Using those dispersions, a monte-carlo was run to determine the most probable particle pa-rameters, as well as the riskiest in terms of full bondline penetration. From these probabilities, a test matrix was designed to test against bounding cases for the various parameters of the BLE: projectile density, projectile mass, projectile velocity, and the impact angle.This presentation will discuss the performance of the dual layer TPS material HEEET against a wide range of impact kinetic energies and densitites, as well as the comparison of HEEET to PICA in terms of MM/OD performance and selectability criteria.

Libben, B. J.↗
NASA NTRS1988

Design of a sample acquistion system for the Mars exobiological penetrator

The Mars Exobiological Penetrator will be imbedded into several locations on the Martian surface. It contains various scientific instruments, such as an Alpha-Particle Instrument (API), Differential Scanning Calorimeter (DSC), Evolved Gas Analyzer (EGA) and accelerometers. A sample is required for analysis in the API and DSC. To avoid impact contaminated material, this sample must be taken from soil greater than 2 cm away from the penetrator shell. This study examines the design of a dedicated sampling system including deployment, suspension, fore/after body coupling, sample gathering and placement. To prevent subsurface material from entering the penetrator sampling compartment during impact, a plug is placed in the exit hole of the wall. A U-lever device is used to hold this plug in the penetrator wall. The U-lever rotates upon initial motion of the core-grinder mechanism (CGM), releasing the plug. Research points to a combination of coring and grinding as a plausible solution to the problem of dry drilling. The CGM, driven by two compressed springs, will be deployed along a tracking system. A slowly varying load i.e., springs, is favored over a fixed displacement motion because of its adaptability to different material hardness. However, to accommodate sampling in a low density soil, two dash pots set a maximum transverse velocity. In addition, minimal power use is achieved by unidirectional motion of the CGM. The sample will be transported to the scientific instruments by means of a sample placement tray that is driven by a compressed spring to avoid unnecessary power usage. This paper also explores possible modifications for size, weight, and time as well as possible future studies.

Thomson, Ron↗
NASA NTRS1995

Penetration experiments in aluminum 1100 targets using soda-lime glass projectiles

The cratering and penetration behavior of annealed aluminum 1100 targets, with thickness varied from several centimeters to ultra-thin foils less than 1 micrometer thick, were experimentally investigated using 3.2 mm diameter spherical soda-lime glass projectiles at velocities from 1 to 7 km/s. The objective was to establish quantitative, dimensional relationships between initial impact conditions (impact velocity, projectile diameter, and target thickness) and the diameter of the resulting crater or penetration hole. Such dimensional relationships and calibration experiments are needed to extract the diameters and fluxes of hypervelocity particles from space-exposed surfaces and to predict the performance of certain collisional shields. The cratering behavior of aluminum 1100 is fairly well predicted. However, crater depth is modestly deeper for our silicate impactors than the canonical value based on aluminum projectiles and aluminum 6061-T6 targets. The ballistic-limit thickness was also different. These differences attest to the great sensitivity of detailed crater geometry and penetration behavior on the physical properties of both the target and impactor. Each penetration experiment was equipped with a witness plate to monitor the nature of the debris plume emanating from the rear of the target. This plume consists of both projectile fragments and target debris. Both penetration hole and witness-plate spray patterns systematically evolve in response to projectile diameter/target thickness. The relative dimensions of the projectile and target totally dominate the experimental products documented in this report; impact velocity is an important contributor as well to the evolution of penetration holes, but is of subordinate significance for the witness-plate spray patterns.

Horz, Friedrich↗
NASA NTRS2016

A FDTD Solution of Scattering of Laser Beam with Orbital Angular Momentum by Dielectric Particles: Far-Field Characteristics

Electromagnetic (EM) beams with orbital angular momentum (OAM) may have great potential applications in communication technology and in remote sensing of the Earth-atmosphere system and outer planets. Study of their interaction with optical lenses and dielectric or metallic objects, or scattering of them by particles in the Earth-atmosphere system, is a necessary step to explore the advantage of the OAM EM beams. In this study, the 3-dimensional (3D) scattered-field (SF) finite-difference time domain (FDTD) technique with the convolutional perfectly matched layer (CPML) absorbing boundary conditions (ABC) is applied to calculate the scattering of the purely azimuthal (the radial mode number is assumed to be zero) Laguerre–Gaussian (LG) beams with the OAM by dielectric particles. We found that for OAM beam׳s interaction with dielectric particles, the forward-scattering peak in the conventional phase function (P11) disappears, and light scattering peak occurs at a scattering angle of ~15° to 45°. The disappearance of forward-scattering peak means that, in laser communications most of the particle-scattered noise cannot enter the receiver, thus the received light is optimally the original OAM-encoded signal. This feature of the OAM beam also implies that in lidar remote sensing of the atmospheric particulates, most of the multiple-scattering energy will be off lidar sensors, and this may result in an accurate profiling of particle layers in the atmosphere or in the oceans by lidar, or even in the ground when a ground penetration radar (GPR) with the OAM is applied. This far-field characteristics of the scattered OAM light also imply that the optical theorem, which is derived from plane-parallel wave scattering case and relates the forward scattering amplitude to the total cross section of the scatterer, is invalid for the scattering of OAM beams by dielectric particles.

Electromagnetic beams↗
NASA NTRS2016

Optical Extinction Measurements of Dust Density in the GMRO Regolith Test Bin

A regolith simulant test bin was constructed and completed in the Granular Mechanics and Regolith Operations (GMRO) Lab in 2013. This Planetary Regolith Test Bed (PRTB) is a 64 sq m x 1 m deep test bin, is housed in a climate-controlled facility, and contains 120 MT of lunar-regolith simulant, called Black Point-1 or BP-1, from Black Point, AZ. One of the current uses of the test bin is to study the effects of difficult lighting and dust conditions on Telerobotic Perception Systems to better assess and refine regolith operations for asteroid, Mars and polar lunar missions. Low illumination and low angle of incidence lighting pose significant problems to computer vision and human perception. Levitated dust on Asteroids interferes with imaging and degrades depth perception. Dust Storms on Mars pose a significant problem. Due to these factors, the likely performance of telerobotics is poorly understood for future missions. Current space telerobotic systems are only operated in bright lighting and dust-free conditions. This technology development testing will identify: (1) the impact of degraded lighting and environmental dust on computer vision and operator perception, (2) potential methods and procedures for mitigating these impacts, (3) requirements for telerobotic perception systems for asteroid capture, Mars dust storms and lunar regolith ISRU missions. In order to solve some of the Telerobotic Perception system problems, a plume erosion sensor (PES) was developed in the Lunar Regolith Simulant Bin (LRSB), containing 2 MT of JSC-1a lunar simulant. PES is simply a laser and digital camera with a white target. Two modes of operation have been investigated: (1) single laser spot - the brightness of the spot is dependent on the optical extinction due to dust and is thus an indirect measure of particle number density, and (2) side-scatter - the camera images the laser from the side, showing beam entrance into the dust cloud and the boundary between dust and void. Both methods must assume a mean particle size in order to extract a number density. The optical extinction measurement yields the product of the 2nd moment of the particle size distribution and the extinction efficiency Qe. For particle sizes in the range of interest (greater than 1 micrometer), Qe approximately equal to 2. Scaling up of the PES single laser and camera system is underway in the PRTB, where an array of lasers penetrate a con-trolled dust cloud, illuminating multiple targets. Using high speed HD GoPro video cameras, the evolution of the dust cloud and particle size density can be studied in detail.

lunar simulant↗
NASA NTRS2012

Computational Transport Modeling of High-Energy Neutrons Found in the Space Environment

The high charge and high energy (HZE) particle radiation environment in space interacts with spacecraft materials and the human body to create a population of neutrons encompassing a broad kinetic energy spectrum. As an HZE ion penetrates matter, there is an increasing chance of fragmentation as penetration depth increases. When an ion fragments, secondary neutrons are released with velocities up to that of the primary ion, giving some neutrons very long penetration ranges. These secondary neutrons have a high relative biological effectiveness, are difficult to effectively shield, and can cause more biological damage than the primary ions in some scenarios. Ground-based irradiation experiments that simulate the space radiation environment must account for this spectrum of neutrons. Using the Particle and Heavy Ion Transport Code System (PHITS), it is possible to simulate a neutron environment that is characteristic of that found in spaceflight. Considering neutron dosimetry, the focus lies on the broad spectrum of recoil protons that are produced in biological targets. In a biological target, dose at a certain penetration depth is primarily dependent upon recoil proton tracks. The PHITS code can be used to simulate a broad-energy neutron spectrum traversing biological targets, and it account for the recoil particle population. This project focuses on modeling a neutron beamline irradiation scenario for determining dose at increasing depth in water targets. Energy-deposition events and particle fluence can be simulated by establishing cross-sectional scoring routines at different depths in a target. This type of model is useful for correlating theoretical data with actual beamline radiobiology experiments. Other work exposed human fibroblast cells to a high-energy neutron source to study micronuclei induction in cells at increasing depth behind water shielding. Those findings provide supporting data describing dose vs. depth across a water-equivalent medium. This poster presents PHITS data suggesting an increase in dose, up to roughly 10 cm depth, followed by a continual decrease as neutrons come to a stop in the target.

Cox, Brad↗
NASA NTRS1980

Improved PFB operations: 400-hour turbine test results

A pressurized fluidized bed (PFB) coal-burning reactor was used to provide hot effluent gases for operation of a small gas turbine. Preliminary tests determined the optimum operating conditions that would result in minimum bed particle carryover in the combustion gases. Solids were removed from the gases before they could be transported into the test turbine by use of a modified two stage cyclone separator. Design changes and refined operation procedures resulted in a significant decrease in particle carryover, from 2800 to 93 ppm (1.5 to 0.05 grains/std cu ft), with minimal drop in gas temperature and pressure. The achievement of stable burn conditions and low solids loadings made possible a 400 hr test of small superalloy rotor, 15 cm (6 in.) in diameter, operating in the effluent. Blades removed and examined metallographically after 200 hr exhibited accelerated oxidation over most of the blade surface, with subsurface alumina penetration to 20 micron m. After 400 hours, average erosion loss was about 25 micron m (1 mil). Sulfide particles, indicating hot corrosion, were present in depletion zones, and their presence corresponded in general to the areas of adherent solids deposit. Sulfidation appears to be a materials problem equal in importance to erosion.

Rollbuhler, R. J.↗
NASA NTRS1992

The effectiveness of multi-layer insulation as meteoroid and orbital debris shielding

This paper presents the results of a study of the penetration resistance of Type I Multi-Layer Insulation (MLI) to meteoroid and orbital debris particles. Hypervelocity impact tests on MLI were performed and the collected data was compared to data and empirical equations developed for aluminum. The study results indicate that MLI can be an effective shield from meteoroids and orbital debris for short duration missions and for non-critical elements. However, long missions which require high levels of protection cannot rely on MLI without a thorough investigation of the overall system reliability.

Robinson, J. H.↗
NASA NTRS1929

Some Effects of Air Flow on the Penetration and Distribution of Oil Sprays

Tests were made to determine the effects of air flow on the characteristics of fuel sprays from fuel injection valves. Curves and photographs are presented showing the airflow throughout the chamber and the effects of the air flow on the fuel spray characteristics. It was found that the moving air had little effect on the spray penetration except with the 0.006 inch orifice. The moving air did, however, affect the oil particles on the outside of the spray cone. After spray cut-off, the air flow rapidly distributed the atomized fuel throughout the spray chamber.

Rothrock, A M↗
NASA NTRS2006

Cassini Thermal Observations of Saturn's Main Rings: Implications for Particle Rotation and Vertical Mixing

In late 2004 and 2005 the Cassini composite infrared spectrometer (CIRS) obtained spatially resolved thermal infrared radial scans of Saturn's main rings (A, B and C, and Cassini Division) that show ring temperatures decreasing with increasing solar phase angle, (alpha), on both the lit and unlit faces of the ring plane. These temperature differences suggest that Saturn's main rings include a population of ring particles that spin slowly, with a spin period greater than 3.6 h, given their low thermal inertia. The A ring shows the smallest temperature variation with (alpha), and this variation decreases with distance from the planet. This suggests an increasing number of smaller, and/or more rapidly rotating ring particles with more uniform temperatures, resulting perhaps from stirring by the density waves in the outer A ring and/or self-gravity wakes. The temperatures of the A and B rings are correlated with their optical depth, (tau), when viewed from the lit face, and anti-correlated when viewed from the unlit face. On the unlit face of the B ring, not only do the lowest temperatures correlate with the largest (tau), these temperatures are also the same at both low and high a, suggesting that little sunlight is penetrating these regions. The temperature differential from the lit to the unlit side of the rings is a strong, nearly linear, function of optical depth. This is consistent with the expectation that little sunlight penetrates to the dark side of the densest rings, but also suggests that little vertical mixing of ring particles is taking place in the A and B rings.

Cassini composite infrared spectrometer (CIRS)↗
NASA NTRS2013

Determine ISS Soyuz Orbital Module Ballistic Limits for Steel Projectiles Hypervelocity Impact Testing

A new orbital debris environment model (ORDEM 3.0) defines the density distribution of the debris environment in terms of the fraction of debris that are low-density (plastic), medium-density (aluminum) or high-density (steel) particles. This hypervelocity impact (HVI) program focused on assessing ballistic limits (BLs) for steel projectiles impacting the enhanced Soyuz Orbital Module (OM) micrometeoroid and orbital debris (MMOD) shield configuration. The ballistic limit was defined as the projectile size on the threshold of failure of the OM pressure shell as a function of impact speeds and angle. The enhanced OM shield configuration was first introduced with Soyuz 30S (launched in May 2012) to improve the MMOD protection of Soyuz vehicles docked to the International Space Station (ISS). This test program provides HVI data on U.S. materials similar in composition and density to the Russian materials for the enhanced Soyuz OM shield configuration of the vehicle. Data from this test program was used to update ballistic limit equations used in Soyuz OM penetration risk assessments. The objective of this hypervelocity impact test program was to determine the ballistic limit particle size for 440C stainless steel spherical projectiles on the Soyuz OM shielding at several impact conditions (velocity and angle combinations). This test report was prepared by NASA-JSC/ HVIT, upon completion of tests.

Lyons, Frankel↗
NASA NTRS2018

Using the Hottest Particles in the Universe to Probe Icy Solar System Worlds

We present results of our Phase 1 NIAC Study to determine the feasibility of developing a competitive, low cost, low power, low mass passive instrument to measure ice depth on outer planet ice moons, such as Europa, Ganymede, Callisto, and Enceladus. Indirect measurements indicate that liquid water oceans are likely present beneath the icy shells of such moons (see e.g.,the JPL press release "The Solar System and Beyond is Awash in Water"), which has important astrobiological implications. Determining the thickness of these ice shells is challenging given spacecraft SWaP (Size, Weight and Power) resources. The current approach uses a suite of instruments, including a high power, massive ice penetrating radar. The instrument under study, called PRIDE (Passive Radio Ice Depth Experiment) exploits a remarkable confluence between methods from the high energy particle physics and the search for extraterrestrial life within the solar system. PRIDE is a passive receiver of a naturally occurring radio frequency (RF) signal generated by interactions of deep penetrating Extremely High Energy (> 10^18 eV) cosmic ray neutrinos. It could measure ice thickness directly, and at a significant savings to spacecraft resources. At RF frequencies the transparency of modeled Europan ice is up to many km, so an RF sensor in orbit can observe neutrino interactions to great depths, and thereby probe the thickness of the ice layer.

Exploration↗