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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 289 records · Page 16

Results of Two-Stage Light-Gas Gun Development Efforts and Hypervelocity Impact Tests of Advanced Thermal Protection Materials

Gun development efforts to increase the launching capabilities of the NASA Ames 0.5-inch two-stage light-gas gun have been investigated. A gun performance simulation code was used to guide initial parametric variations and hardware modifications, in order to increase the projectile impact velocity capability to 8 km/s, while maintaining acceptable levels of gun barrel erosion and gun component stresses. Concurrent with this facility development effort, a hypervelocity impact testing series in support of the X-33/RLV program was performed in collaboration with Rockwell International. Specifically, advanced thermal protection system materials were impacted with aluminum spheres to simulate impacts with on-orbit space debris. Materials tested included AETB-8, AETB-12, AETB-20, and SIRCA-25 tiles, tailorable advanced blanket insulation (TABI), and high temperature AFRSI (HTA). The ballistic limit for several Thermal Protection System (TPS) configurations was investigated to determine particle sizes which cause threshold TPS/structure penetration. Crater depth in tiles was measured as a function of impact particle size. The relationship between coating type and crater morphology was also explored. Data obtained during this test series was used to perform a preliminary analysis of the risks to a typical orbital vehicle from the meteoroid and space debris environment.

Cornelison, C. J.↗

Overview of the Capture, Containment, and Return System (CCRS)

The Mars Sample Return (MSR) campaign is one of the most ambitious and complex planetary exploration missions currently underway. With the participation of NASA, ESA, and a large number of industry partners, MSR aims to bring Martian soil, rock, and atmospheric samples back to Earth, in order to answer key questions about Mars’ biological evolution. To accomplish this goal the campaign relies on four coordinated missions, each fulfilling a fundamental role to bring the samples to Earth. The Mars Perseverance rover, the first of the four missions, landed safely on Mars on February 18, 2021 and has already acquired candidate samples for Earth return. A selection of the samples of Martian soil and atmosphere that Perseverance has captured during its mission will be recovered, launched into Mars orbit, and transported back to Earth. The Sample Fetch Rover and Mars Ascent System, both parts of the Sample Return Lander project, perform the Mars surface missions to retrieve the collected samples and launch them into Mars orbit. NASA’s Capture, Containment, and Return System (CCRS), hosted on ESA’s Earth Return Orbiter (ERO), brings the samples back to Earth from Mars orbit. These retrieval and return missions are currently in the planning and design stages of development. The NASA-provided CCRS is the payload of the ESA ERO and is the focus of this presentation. ERO will enter Mars orbit and provide communication relay to Earth for the other MSR elements. The Sample Return Lander systems will fetch the sample tubes and integrate them into a protective vessel – the Orbiting Sample (OS) system – which is then launched into low Mars orbit. ERO will perform rendezvous maneuvers, allowing its CCRS payload to capture the OS, contain it, and perform the first automated in-space assembly of a spacecraft, the Earth Entry System (EES), while in Mars orbit. ERO will then begin its journey back to Earth, with CCRS and its assembled EES spacecraft. Three days prior to arrival, CCRS will release the EES on an Earth entry trajectory from a distance beyond the orbit of the Moon. The passive EES spacecraft will then enter Earth’s atmosphere, flying on a ballistic trajectory, followed by a terminal descent (without a parachute) and landing at the Utah Test and Training Range (UTTR). This presentation will show the current design of the CCRS system and its concept of operations. ERO and CCRS will perform several firsts in planetary exploration: (a) orbital rendezvous and capture in Mars orbit, (b) in-space sterilization and containment, (c) on-orbit spacecraft assembly at Mars, and (d) fully-passive entry, descent, and landing sequence for sample return.

Carlie H. Zumwalt↗

Guidance and Control Architecture Design and Demonstration for Low Ballistic Coefficient Atmospheric Entry

We propose to develop a robust guidance and control system for the ADEPT (Adaptable Deployable Entry and Placement Technology) entry vehicle. A control-centric model of ADEPT will be developed to quantify the performance of candidate guidance and control architectures for both aerocapture and precision landing missions. The evaluation will be based on recent breakthroughs in constrained controllability/reachability analysis of control systems and constrained-based energy-minimum trajectory optimization for guidance development operating in complex environments.

Entry↗

A Frequency Domain Methodology for Quantitative Evaluation of Diffuse Wavefield With Applications to Seismic Imaging

Abstract Ambient Noise Imaging (ANI) of subsurface structures relies on seismic interferometry of diffuse seismic wavefields. However, the lack of effective methods to quantify and identify highly diffuse waves hampers applications of ANI, particularly in evaluating seismic attenuation and monitoring structural changes with high temporal resolution. Conventional ANI approaches require data normalization, which effectively suppresses the non‐diffuse component with large amplitude but also results in significant loss of amplitude and phase information in the continuous seismic records. In this study, we propose a frequency domain method to quantitatively evaluate the degree of diffuseness of seismic wavefields by analyzing their statistical characteristics of modal amplitudes for stationarity and randomness. Tests on synthetic waveform and field nodal records show that the proposed method can effectively distinguish between diffuse and non‐diffuse waveforms for either single‐ or three‐component data. As an application, we identify a 60‐s‐long diffuse coda of a local M 2.2 earthquake recorded by a dense nodal array on the San Jacinto Fault Zone, and successfully extract high‐quality dispersion curve andQ‐value without performing data normalization. These results are consistent with those obtained by conventional methods that assess the correlation between coherency and the Green's function, and by modeling ballistic waves generated by road traffic. Our proposed method can advance the imaging of subsurface velocity and attenuation structures as well as monitoring temporal changes for scientific studies and engineering applications.

Geochemistry & Geophysics↗

SERV - A reusable single stage to orbit space shuttle concept

Feasibility studies were made on the SERV (Single-stage Earth-orbital Reusable Vehicle), which is a single-stage, fully reusable space shuttle concept. The studies show that a reusable single-stage-to-orbit shuttle can be built using present technology. The SERV satisfies all of NASA's requirements for low earth orbital and space station resupply missions. The baseline vehicle has a modified Apollo external configuration, 90 ft in diameter and 66 ft in height, with a cargo hold 23 ft in diameter and 60 ft long. Take-off is vertical, powered by an integral aerospike rocket engine. An Apollo-type ballistic reentry profile is used, and precision vertical landing is possible with power provided by an array of turbojet engines. The key feasibility issues discussed are engine performance, aerodynamic drag, subsystem weights, method and type of thermal protection during reentry, descent aerodynamic characteristics, and landing method.

Tharratt, C. E.↗

Imaging on ballistic missions to comet Encke

Imaging for navigation and science has been studied for a 1980 Encke flyby at 0.4 to 0.8 AU from the sun with spinning and three-axis spacecraft. Trajectory errors, maneuvers, encounter geometry, imaging performance, and data transmission were considered. Onboard comet sightings are needed for navigation. Recommended for a three-axis spacecraft are two vidicon cameras and a nucleus sensor for closed-loop pointing control. The cameras are essentially the Mariner 9 and Mariner 10 instruments; the nucleus sensor is an updated version of a sensor flown on Mariners 6 and 7. For a spinning spacecraft, a framing camera using a charge-coupled device and a spin-scan photometer are proposed. The framing camera would be a new design; it would not be despun, but the spin axis should point along the comet-centered velocity vector. The photometer is essentially that flown on Pioneer 10 and 11.-

Jaffe, L. D.↗

Project Genesis: Mars in situ propellant technology demonstrator mission

Project Genesis is a low cost, near-term, unmanned Mars mission, whose primary purpose is to demonstrate in situ resource utilization (ISRU) technology. The essence of the mission is to use indigenously produced fuel and oxidizer to propel a ballistic hopper. The Mars Landing Vehicle/Hopper (MLVH) has an Earth launch mass of 625 kg and is launched aboard a Delta 117925 launch vehicle into a conjunction class transfer orbit to Mars. Upon reaching its target, the vehicle performs an aerocapture maneuver and enters an elliptical orbit about Mars. Equipped with a ground penetrating radar, the MLVH searches for subsurface water ice deposits while in orbit for several weeks. A deorbit burn is then performed to bring the MLVH into the Martian atmosphere for landing. Following aerobraking and parachute deployment, the vehicle retrofires to a soft landing on Mars. Once on the surface, the MLVH begins to acquire scientific data and to manufacture methane and oxygen via the Sabatier process. This results in a fuel-rich O2/CH4 mass ratio of 2, which yields a sufficiently high specific impulse (335 sec) that no additional oxygen need be manufactured, thus greatly simplifying the design of the propellant production plant. During a period of 153 days the MLVH produces and stores enough fuel and oxidizer to make a 30 km ballistic hop to a different site of scientific interest. At this new location the MLVH resumes collecting surface and atmospheric data with the onboard instrumentation. Thus, the MLVH is able to provide a wealth of scientific data which would otherwise require two separate missions or separate vehicles, while proving a new and valuable technology that will facilitate future unmanned and manned exploration of Mars. Total mission cost, including the Delta launch vehicle, is estimated to be $200 million.

Acosta, Francisco Garcia↗

The effect of solid phase reactions on the ballistic properties of propellants

The combustion of NHClO4 composite propellants was studied between 15 and 3000 psi. The emphasis was on determining the mechanisms by which the fuel components influence the burning rate of the composites. All combustion experiments were performed with pressed powder strands. The fuels affected the combustion mechanism of the composite through their effect on the oxidizer decomposition mechanism, the composite surface temperature, and by reacting heterogeneously with the oxidizer on the surface of the composite. The results indicate that the fuel component has a significant effect on the surface temperature in both catalyzed and uncatalyzed composites. The data suggest that the contribution, to the overall combustion reaction, of heterogeneous reactions increases with increasing pressure. There is also evidence that even in steady state combustion the ignition of individual oxidizer particles is an important parameter in determining the combustion characteristics of the composite.

Schmidt, W. G.↗

Cryocooler Electromagnetic Compatibility

Jet Propulsion Laboratory, under joint Ballistic Missile and Defense Organization/Air Force and NASA/Eos Atmospheric Infrared Sounder sponsorship is conducting extensive space cryocooler characterization to provide a reliable and accurate data base on cryocooler performance for use by the space community.

cryocooler electromagnetic compatibility cryocoole↗

Cryocooler Electromagnetic Compatibility

The Jet Propulsion Laboratory, under joint Ballistic Missile and Defense Organization/Air Force and NASA/Eos Atmospheric Infrared Sounder sponsorship, is conducting extensive space cryocooler characterization to provide a reliable and accurate data base on cryocooler performance for use by the space community.

detector↗

Modeling of Response of Thermoplastic Composites Under High Energy Impact

This work investigates the response of a thermoplastic panel under high energy ballistic impact. The composite material system is a carbon fiber reinforced low melt semi-crystalline resin TC1225 LMPAEK T700G (T700/LMPAEK3). Several high energy dynamic impact tests were performed where an aluminum projectile impacted various panels at different impact velocities. For this work, the test performed at an impact velocity of 73.2 m/s was investigated. The projectile rebounded upon impact, and the damage to the panel was characterized through ultrasonic and CT-scanning. Response of the panel under impact and the associated damage is discussed. Numerical simulation of the impact process was performed using the LS-DYNA® computer code [1] with a new material model MAT_COMPOSITE_DAMAGE_DGD (MAT 299), a modification over MAT 261 material model in terms of an improved representation of damage coupling and additional capability for strain rate effects. Delaminations were modeled using cohesive zone contact formulation in LS-DYNA®, wherein the mixed-mode fracture is captured via the Benzegaggh-Kenane (B-K) mode-dependent fracture energy interpolation law. Simulation of this impact test demonstrates a good match of results in terms of panel deflection and panel-projectile interactions. The overall extent of delaminations was under-predicted by the simulation. This work forms the basis to model tests performed at higher velocities, involving projectile penetration of panel.

Composite Materials↗

Irradiation-enhanced diffusion and diffusion-limited creep in U 3 Si 2

U 3 Si 2 is an advanced fuel candidate due to its relatively high fissile density and attractive thermal properties. Compared to standard UO 2 fuel, there are significant data gaps for the thermophysical and thermomechanical properties of U 3 Si 2 . Point defect concentrations and mobilities under irradiation govern a number of important fuel performance properties, such as creep and fission gas release. In this work, we utilized density functional theory (DFT) data to inform a cluster dynamics framework to predict point defect concentrations in U 3 Si 2 under irradiation. Molecular dynamics (MD) simulations were used to examine the contribution of atomic mixing during ballistic cascades to diffusion, as well as the diffusivity of U and Si at grain boundaries. These atomic scale models for diffusivity were then used to inform a creep model based on bulk (Nabarro-Herring) and grain boundary (Coble) diffusional creep, and climb-limited dislocation creep. The model compares well against available experimental data and has been implemented in the BISON fuel performance code. Finally, a demonstration case using simple power profiles has been carried out, showing that negligible creep occurs due to the low temperatures experienced by U 3 Si 2 in-reactor, a consequence of its high thermal conductivity.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Assessing the Effects of Various Surface Textures and Features on Turbulent Heat Transfer in Hypersonic Flight

Experiments were conducted in the NASA Ames Hypervelocity Free Flight Aerodynamic Facility (ballistic range) to quantify the effects on turbulent convective heat transfer of distributed surface roughness, and of isolated features, representative of thermal protection systems on atmospheric entry vehicles. The surface textures and features were applied on the conic frusta of 45o sphere-cone models having a nose-to-base radius ratio of 0.5, similar to the forebody geometry of the Galileo and Pioneer-Venus entry probes. Test conditions were selected to provide turbulent roughness Reynolds numbers, k+, in the ranges expected for outer planet entry missions. Turbulent flow on the conic frustum was achieved by tripping the flow on the sphere-segment nose cap with distributed surface roughness, created by sand-blasting the nose cap. Surface textures included distributed, acreage, roughness, as well as cavity and groove discrete features. The majority of the data to be presented are results for distributed roughness, which includes both random, sand-grain-like roughness, and regular pattern roughness. The pattern roughness was designed to represent the roughness on woven thermal protection system materials, such as NASA’s 3-D Medium Density Carbon Phenolic (3MDCP), also known as HEEET, developed by the Heatshield for Extreme Entry Environments Technology project. The pattern roughness tested is a 3-D wavy surface, and includes three different roughness element height-to-spacing ratios representative of two configurations of 3MDCP, and spanning ratios measured both before, and after, ablation in an arc jet test facility. The patterns tested in the ballistic range were laser-etched on metal models, and represented an idealized version of the real-world materials in which each roughness element was nearly identical. Additional tests were performed wherein the laser-etched patterns were degraded by sand-blasting with various sized grit media, to produce regular patterns with superimposed irregular roughness, more representative of flight materials. Results of each will be compared. The discrete features tested included cylindrical cavities and rectangular grooves of various width-to-depth ratios. Cavities represent either heatshield damage, such as from micro-meteoroid and orbital debris (MMOD) damage, or from designed penetrations, such as on the Genesis sample return capsule. The grooves were scaled representations of seams between segments of HEEET material in a notional tiled thermal protection system. The tests examined the effects on turbulent heating downstream of the isolated features. The tests were conducted at speeds between 3 km/s and 4 km/s in air between 0.15 atm and 0.25 atm (Mach numbers between 9 and 12). Roughness Reynolds numbers, k+, ranged from 12 to 70 for the sand roughness, and as high as 200 for the pattern roughness. Boundary-layer parameters required for calculating k+ were evaluated using computational fluid dynamics simulations using the DPLR (Data Parallel Line Relaxation) code. Each model included both rough- and smooth-wall segments, and heat transfer augmentation factors were determined as the ratio of the rough-wall to smooth-wall heat flux measured on each test.

hypersonic↗

Study of ballistic mode comet Encke mission opportunities

An analysis was conducted of the space mission to intercept the comet Encke. The two basic types of flight geometry considered for the mission are described. The primary interactions between time-of-flight and performance characteristics are displayed. The representative spacecraft characteristics for the Titan 3/Centaur launch vehicle are tabulated. The navigation analyses for the two missions are developed to show: (1) assessment of the navigation feasibility of the missions, (2) determination of the total velocity budget for the trim maneuvers, and (3) evaluation of dispersions at comet encounter.

Hollenbeck, G. R.↗

In-situ irradiation-induced studies of grain growth kinetics of nanocrystalline UO 2

The thermal conductivity of UO 2 fuel needs to be high enough to dissipate the heat generated from the fission reaction. Since grain size affects thermal conductivity and grain size can evolve with irradiation, it is critical to understand in-reactor UO 2 grain growth. Most studies of grain growth in UO 2 are based on thermally driven processes at elevated temperatures. However, studies have shown that grain growth can occur even at cryogenic temperatures by ballistic processes. Such irradiation-induced grain growth in UO 2 is yet to be studied. Advanced in-situ Kr ion irradiation and transmission electron microscopy were systematically performed on nanocrystalline UO 2 thin films at temperatures ranging from 50 K to 1073 K; grain growth was observed at all temperatures. A combination of manual and machine learning techniques was used to measure and plot grain size evolution against irradiation fluence at various irradiation temperatures. The machine learning method has significantly improved the analysis efficiency and reduced human labors. The grain diameter data were fitted using classical grain growth and thermal spike models to describe grain growth kinetics with and without irradiation effect. Grain growth during low temperature irradiation (≤ 475 K) can be well described by the thermal spike model. Above 475 K, there were additional thermally assisted processes that further accelerate the grain growth. At the highest irradiation temperature about 1075 K, both irradiation-induced dislocation loops and cavities/bubbles were observed to form in the UO 2 . In this report, the effects of irradiation-induced defects on grain growth kinetics are discussed.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

A GNM mission and system design proposal

Here, the author takes an advocacy position for the proposed Mars Global Network Mission (GNM); it is not intended to be an objective review, although both pros and cons are presented in summary. The mission consists of launches from earth in the '96, '98, and '01 opportunities on Delta-class launch vehicles (approx. 1000 kg injected to Mars in 8 to 10 ft diameter shroud). The trans Mars boost stage injects a stack of small independent, aeroshelled spacecraft. The stack separates from the boost stage and each rigid (as opposed to deployable) aeroshell flies to Mars on its own, performing midcourse maneuvers as necessary. Each spacecraft flies a unique trajectory which is targeted to achieve approach atmospheric interface at the desired latitude and lighting conditions; arrival times may vary by a month or more. A direct entry is performed, there is no propulsive orbit capture. The aeroshelled rough-landers are targeted to achieve a desired attitude and entry flight path angle, and then follow a passive ballistic trajectory until terminal descent. Based on sensed acceleration (integrated to deduce altitude), the aft aeroshell skirt is jettisoned; a short later a supersonic parachute is deployed. The ballistic coefficient of the parachute is sized to achieve terminal velocity at about 8 km. However the parachute is not deployed until a few Km above the surface to minimize wind-induced drift. The nose cap descent imaging begins, a laser altimeter also measures true altitude. Based on range and range rate to the surface, the parachute is jettisoned and the lander uses descent engines to achieve touchdown velocity. A contact sensor shuts down the motors to avoid cratering, and the lander rough-lands at less than 5 m/sec. The remaining aeroshell and a deployable bladder attenuate landing loads and minimize the possibility of tip over. Science instruments are deployed and activated, and the network is established.

Bailey, Stephen↗

A Reliable Earth Return System for Safe Recovery of Mars Samples

The objective of a Mars sample return mission is to bring selected Mars surface materials to Earth. Numerous approaches for the Earth-return segment have been analyzed including propulsive or aerocapture return to low-Earth orbit followed by Space Shuttle rendezvous and direct entry. Of these approaches, ballistic entry of a small capsule terminating in a ground landing has been shown to be the lowest risk strategy. Over the past two years, significant work has been performed towards development of a robust direct entry vehicle for Mars sample return. In June 1999, the NASA Planetary Protection Officer provided initial guidance to the former Mars Sample Return Project. The sample return phase of the mission was assigned a restricted Earth return planetary protection classification. The draft mission requirement states that the total mean probability of release of unsterilized Mars material into the Earth;s biosphere must be less than 1.0E-06 (1 in a million). This strict requirement drives the approach and design of the Earth return system. To meet this requirement, selection of the Earth return strategy and development of the Earth return system must be guided by risk, not performance, based decisions. An initial Probabilistic Risk Assessment (PRA) was performed to address the direct entry Earth return system containment assurance reliability and to identify high-risk elements of this system. The results of this PRA identified risk elements that include thermal protection system performance during entry, spin-eject orientation and aerodynamic stability during entry, structural integrity under atmospheric deceleration and impact loads, and tracking/recovery of this system. This initial probabilistic risk quantification demonstrates that, with the proper development program, a prototypical direct entry design can satisfy the containment assurance reliability requirement. Through the current Mars Sample Return Advanced Technology Development effort, an extensive design, analysis, and test program is presently proceeding with the aim of reducing the containment assurance risk of this system. This technology development effort, guided by a continuing PRA, focuses on key risk areas of a direct entry Earth return system including: the thermal protection system, impact dynamics, structural performance, aerodynamic stability, and ground recovery. This development program will culminate in a system validation flight test, 1-2 years prior to launch of the flight system. This flight test would include the launch, entry, and recovery of a full-scale Earth return system, as a scientific validation of the key risk elements to verify nominal design performance. The results of the initial PRA suggested several dominant failure sequences that can be validated in a flight test. These include: demonstrating the thermal protection system reliability and performance during entry, demonstrating the spin-eject orientation and aero-dynamic stability during entry, demonstrating the structural integrity under atmospheric deceleration and impact loads, and demonstrating tracking and recovery of the Earth return system. This single test will directly address over 50% of the total containment assurance risk elements. This presentation will begin by presenting the relative risk of various Earth return strategies. The results of the initial probabilistic risk assessment will be presented followed by a discussion of the development accomplishments and plans for demonstration of a highly reliable direct entry Earth return system.

Braun, R.↗

Investigating the relationship between radial pre-stress magnitude and ballistic projectile dwell in heavy confined ceramic targets

A series of bare silicon carbide ceramic armour disks were manufactured with high-strength steel containment to induce varying magnitudes of radial pre-stress. The induced radial stresses, ranging from 0 to 900 MPa, were measured via neutron diffraction and verified by comparison with numerical calculations. Four targets of each configuration, referred to as slip-fit, moderate pre-stress, and high pre-stress, were subject to ballistic testing with hemispherical-nose, tungsten heavy alloy long rod projectiles to determine the interface defeat transition velocity. In-situ diagnostics were unsuccessful in aiding the identification of interface defeat, necessitating a reliance on post-mortem assessment. A transition velocity of approx. 1000 m/s was identified for the unstressed target, increasing to approx. 1200 m/s for the pre-stressed configurations. No performance effect was discernible between the moderate (372 MPa) and high (899 MPa) pre-stress configurations, suggesting that an optimal performance may be achieved for lower pre-stress levels (i.e., <372 MPa). Additionally, the test results were compared with four semi-analytical predictions of interface defeat performance and good agreement was found, albeit with significant range in the model predictions.

42 ENGINEERING↗