Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “solid Earth”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 649 records · Page 36
All sourcesNASA NTRSDOE OSTI
NASA NTRS2013

Spacecraft Parachute Recovery System Testing from a Failure Rate Perspective

Spacecraft parachute recovery systems, especially those with a parachute cluster, require testing to identify and reduce failures. This is especially important when the spacecraft in question is human-rated. Due to the recent effort to make spaceflight affordable, the importance of determining a minimum requirement for testing has increased. The number of tests required to achieve a mature design, with a relatively constant failure rate, can be estimated from a review of previous complex spacecraft recovery systems. Examination of the Apollo parachute testing and the Shuttle Solid Rocket Booster recovery chute system operation will clarify at which point in those programs the system reached maturity. This examination will also clarify the risks inherent in not performing a sufficient number of tests prior to operation with humans on-board. When looking at complex parachute systems used in spaceflight landing systems, a pattern begins to emerge regarding the need for a minimum amount of testing required to wring out the failure modes and reduce the failure rate of the parachute system to an acceptable level for human spaceflight. Not only a sufficient number of system level testing, but also the ability to update the design as failure modes are found is required to drive the failure rate of the system down to an acceptable level. In addition, sufficient data and images are necessary to identify incipient failure modes or to identify failure causes when a system failure occurs. In order to demonstrate the need for sufficient system level testing prior to an acceptable failure rate, the Apollo Earth Landing System (ELS) test program and the Shuttle Solid Rocket Booster Recovery System failure history will be examined, as well as some experiences in the Orion Capsule Parachute Assembly System will be noted.

Stewart, Christine E.↗
NASA NTRS1985

A model for core formation in the early Earth

Two basic types exogenous models were proposed to account for siderophile and chalcophile element abundances in the Earth's upper mantle. The first model requires that the Earth be depleted in volatiles and that, after a core formation event which extracted the most siderophile elements into the core, additional noble siderophile elements (Pt, Ir, Au) were added as a late veneer and mixed into the mantle. The second model postulates a reduced Earth with approximately CI elemental abundances in which a primary core forming event depleted all siderophile elements in the mantle. The plausibility of models which require fine scale mixing of chondritic material into the upper mantle is analyzed. Mixing in liquids is more efficient, but large degrees of silicate partial melting will facilitate the separation of magma from residual solids. Any external events affecting the upper mantle of the Earth should also be evident in the Moon; but siderophile and chalcophile element abundance patterns inferred for the mantles of the Earth and Moon differ. There appear to be significant physical difficulties associated with chondritic veneer models.

Jones, J. H.↗
DOE OSTI2022

Atomically precise control of rotational dynamics in charged rare-earth complexes on a metal surface

Abstract Complexes containing rare-earth ions attract great attention for their technological applications ranging from spintronic devices to quantum information science. While charged rare-earth coordination complexes are ubiquitous in solution, they are challenging to form on materials surfaces that would allow investigations for potential solid-state applications. Here we report formation and atomically precise manipulation of rare-earth complexes on a gold surface. Although they are composed of multiple units held together by electrostatic interactions, the entire complex rotates as a single unit when electrical energy is supplied from a scanning tunneling microscope tip. Despite the hexagonal symmetry of the gold surface, a counterion at the side of the complex guides precise three-fold rotations and 100% control of their rotational directions is achieved using a negative electric field from the scanning probe tip. This work demonstrates that counterions can be used to control dynamics of rare-earth complexes on materials surfaces for quantum and nanomechanical applications.

36 MATERIALS SCIENCE↗
NASA NTRS1992

Dynamics of the Venus atmosphere

The superrotation of the Venus atmosphere is a major unanswered problem in planetary science. At cloud-top levels (65-70 km altitude) the atmosphere rotates with a five-day period, corresponding to an equatorial wind speed of 90 m/s. Angular velocity is roughly constant on spherical shells, and decreases linearly with altitude to zero at the surface. The direction of rotation is the same as that of the solid planet, which is retrograde--opposite to the direction of orbital motion, but the 5-day period is short compared to the 243-day spin period of the solid planet or to the mean solar day, which is 117 Earth-days at the surface. The problem with the superrotation is that shearing stresses tend to transfer angular momentum downward, and would slow the atmosphere until it is spinning with the solid planet. Some organized circulation pattern is counteracting the tendency, but the pattern has not been identified. A simple Hadley-type circulation cannot do it because such a circulation is zonally symmetric and Hide's Theorem states that in an axisymmetric circulation an extremum in angular momentum per unit mass M can exist only at the surface. Venus violates the last condition, having a maximum of retrograde M on the equator at 70-80 km altitude. This leaves waves and eddies to maintain the superrotation but the length scales and forcing mechanisms for these motions need to be specified. Possible forcing mechanisms associated with waves, eddies and tides are discussed.

Ingersoll, A. P.↗
DOE OSTI2025

MXene/graphitic carbon nitride-supported metal selenide for all-solid-state flexible supercapacitor and oxygen evolution reaction

We report a new type of combination of rare earth metal selenides (Ce 2 Se 3 and Er 2 Se 3 ) with a Ti 3 C 2 T x /S-doped graphitic carbon nitride heterostructure for bifunctional application in flexible supercapacitors and oxygen evolution reactions. The incorporation of S-doped graphitic carbon nitride in MXenes reduced the layer stacking tendency of both two-dimensional sheets and eliminated volume expansion by forming a heterostructure. Cerium and erbium rare earth metal centers induce reactive surface sites, whereas binary layers of Ti 3 C 2 T x /S-doped graphitic carbon nitride provide a conducting matrix for the homogeneous growth of the metal selenides. The assembled all-solid-state flexible asymmetric supercapacitor exhibited a high specific capacitance of 60 F g –1 , an energy density of 10.1 W h kg –1 (volumetric energy density: 0.9 mW h cm –3 ) at 2 A g –1 , and 100% capacitance retention after 10 000 charge–discharge cycles with good flexibility for real-time applications. Furthermore, the optimum nanohybrid showed a low overpotential of 280 mV and a Tafel slope of 99 mV dec –1 with durable electrocatalytic performance. Furthermore, this work is the first to investigate the bifunctional energy efficiency of rare earth metal selenides grown over MXene materials.

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

Tunable Magnetic Exchange between Rare-Earth Metal 5d and Iron 3d States: A Case Study of the Multiple Magnetic Transitions in Gd 6 FeBi 2 and the Solid Solutions Dy 6– x Gd x FeBi 2 (1 ≤ x ≤ 5) with Curie Temperatures in the Range 120–350 K

In this paper, the room-temperature magnet Gd 6 FeBi 2 was comprehensively characterized by means of temperature-dependent single-crystal X-ray diffraction, magnetization measurements, and experimental electron density and electronic structure computations. This work explores the electron-spin effects of Fe on this structure and suggests that Gd6FeBi2 shows structural features and exchange interactions, which are clearly distinguishable from other analogues, including the solid solutions Dy 6–x Gd x FeBi 2 (0 ≤ x ≤ 5). The unique traits of Gd 6 FeBi 2 and its derivatives encompass abnormal variations of lattice parameters with the temperature, as well as the presence of multiple magnetic transitions of complex nature. Based on the comprehensive analyses, it can be suggested that the unique magnetic response in this material is the result from tunable Fe spin states, which are coupled with strong Gd 5d–Fe 3d interactions, which differ from other members of this large, structural family. In the ground state, according to density functional theory calculations, the Fe atom carries two net electrons, whose spins are coupled in an antiparallel fashion to the spins of the Gd electrons. Near the Curie temperature, the Fe net moment is reduced intermittently, coupled with a multiple of magnetic transitions. The magnetic correlations are manifested in unexpected variations of the lattice parameters as a function of temperature, suggesting spin–lattice interactions. Furthermore, this study emphasizes the important role of Gd 5d electrons in tuning Fe 3d-based magnetic contribution, which enables better understanding on the spin coupling in other related compounds and sheds light on the development of new magnetic and spintronic compounds.

36 MATERIALS SCIENCE↗
NASA NTRS2024

Plasma-Based Elemental Analyzer for Crewed Transit and Planetary Habitation

As NASA continues to perform research on the ISS and move towards the Moon and Mars, it is important for astronauts to have a technology capable of determining the composition of solid, liquid, and gas samples. Currently, samples are transported back to Earth for analysis, which may impact results due to the time delay of samples waiting to be returned to Earth as well as potential sample contamination from re-entry, change in environment, and various personnel handling. Therefore, researchers at the Applied Chemistry Lab at KSC have developed a proof-of-concept “Plasma-Based Elemental Analyzer,” which has the capability of testing solid, liquid, and gas samples for identification. Currently, the analysis is only qualitative, with quantitative identification left for future work. This technology is similar to ICP-OES, but differs in instrument size and sample preparation. Both technologies use plasma to ionize samples for light emission. The plasma elemental analyzer aims to be portable and lightweight, require only electrical power, and analyze solid, liquid, and gas samples. It does not use acid digestion or a nebulizer, requires less power than ICP-OES, and is able to operate with minimal to no usage of argon gas. Furthermore, the plasma elemental analyzer operates within low power constraints, which makes it feasible for usage on future missions with higher power constraints. The technology was tested at atmospheric pressure using mostly room air as the carrier gas for plasma production in the proof-of-concept study. The results showed the peak signals of the elements with an associated arbitrary signal intensity that allowed for qualitative identification. Solid samples that were tested included inedible biomass from the Golden Heirloom Cherry Tomato plant and Lunar Highlands Simulants (LHS-1). The liquid samples included elements of interest for the space crop production community. This work showed that a system smaller than the traditional ICP-OES equipment is able to be designed and implemented in future use cases, although it requires further development.

Kenneth Engeling↗
NASA NTRS2020

Small Business Launches Down-to-Earth Products via NASA SBIR Program

Through the SBIR program, DSSP developed a multi-pulse solid rocket motor for NASA that will enable stabilized interplanetary flight for small satellites. Another of DSSP’s core innovations with roots in the SBIR program is already having an even greater impact. Originally proposed to fuel a microsatellite thruster for Earth-observation missions, DSSP’s HAN-based green electric monopropellants (GEM and AF-M315E) technology is powering larger satellites, enhancing downhole oil and gas recovery, and much more. Highly insensitive to ignition by spark, flame, or shock, GEM-based innovations are stable, non-toxic, and more controllable than conventional propellants.

Bruce R Cogan↗
NASA NTRSDate not supplied

The Comet Astrobiology Exploration Sample Return (CAESAR) Mission

The Comet Astrobiology Exploration Sample Return (CAESAR) mission will acquire and return to Earth for laboratory analysis a minimum of 80 grams of surface material from the nucleus of comet 67P/Chur-yumov-Gerasimenko (67P). CAESAR will characterize the surface region sampled, preserve the collected sample in a pristine state, and return evolved volatiles by capturing them in a separate gas reservoir. NASA Goddard Space Flight Center provides project management, systems engineering, safety and mission assurance, contamination control, mission operations, and many other important functions. Northrop Grumman Space Systems will build the spacecraft, based on Dawn mission heritage, which like CAESAR, uses solar electric propulsion. CAESAR was selected by for Phase A study in the New Frontiers 4 Competition and will be proposed to New Frontiers 5.Collection of a sample from the surface of comet 67P is facilitated by a set of cameras that together provide images to support sample site selection, perform optical navigation, and document the sample before, during, and after col-lection. The sample is collected at the end of an arm during a 5-second touch-and-go (TAG) maneuver with the Sample Acquisition System (SAS)designed by Honeybee Robotics for the surface properties of comet 67P observed by the Rosetta mission. After sample collection, and while the sample is still cold (< -80°C), the TAG Arm inserts the sample container into the Sample Containment System (SCS) mounted inside the Sample Return Capsule (SRC). The SCS is sealed, preventing the sample from escaping into space. The sample is slowly warmed inside the SCS to enable sublimation of volatiles, which are collected in the Gas Containment System (GCS), a passively cooled gas reservoir. Separating the volatiles from the solid sample protects the solid sample from alteration. Once all sublimated H2O is transferred to the GCS, the GCS is sealed to capture the volatile sit contains, and the SCS is vented to space to maintain the solid sample under vacuum. The SCS vent is closed before Earth entry to prevent atmospheric contamination. Detailed laboratory analyses of the sample from 67P will trace the history of volatile reservoirs, delineate the chemical pathways that led from simple interstellar species to complex molecules, constrain the evolution of the comet, and evaluate the role of comets in delivering water and prebiotic organics to the early Earth. CAESAR will achieve these goals by carrying out coordinated sample analyses that will link macroscopic properties of the comet with microscale mineralogy, chemistry, and isotopic studies of volatiles and solids. Most of the sample (≥75%) will be set aside for analyses by generations of scientists using continually advancing tools and methods, yielding an enduring scientific treasure that only sample return can provide. This presentation will review development conducted during NF4 Phase A and discuss the NF5 mission concept.

A G Hayes↗
NASA NTRS1961

Objectives of the Mariner Venus Microwave Radiometer Experiment

At present, there are several models involving the surface, atmosphere (and ionosphere), and cloud conditions of the planet Venus which attempt to account for the observed high brightness temperature of 600 degrees Kelvin in the microwave temperature region. None of these models can be definitely accepted or rejected on the basis of presently available data, and it is the goal of the microwave radiometer experiment planned for the Mariner Venus mission to determine which of the proposed models most nearly approximates Venusian conditions. The disc of the planet will be scanned at 4 wavelengths - 4, 8, 13.5 and 19 millimeters - to measure the temperature distribution across the planet. Measurement accuracy is expected to be to within 2 percent. In addition to the study of gross thermal characteristics of surface and atmosphere (or ionosphere), some information regarding the fine-scale thermal variations will be obtained. Since Venus appears to be continuously covered by clouds, it is obvious that only in the microwave region can one be sure of penetrating clear to the solid surface. Because of the absorbing characteristics of the Earth's atmosphere, and because of the relatively poor resolution obtainable in this region of the spectrum, one is forced to utilize the platform afforded by a planetary flyby or orbiter in order to conduct a reliable high resolution study of the planet. To do so from Earth (neglecting terrestrial atmospheric attenuation ) would require colossal radio telescopes.

RADIO ASTRONOMY↗
NASA NTRS1965

Infrared instrumentation in space exploration.

IR spectrometers, radiometers, horizon sensors, rotating-prism planet-seekers and detector cooling using solid cryogens, for use in high altitude rockets and Earth satellites

ROCKET INSTRUMENTATION↗
NASA NTRS1978

Liquid spreading ASTP Science Demonstration

Wetting and spreading phenomena are significant in a wide variety of processes. This report discusses the results of an ASTP Science Demonstration, 'Liquid Spreading', and compares these results to theoretical predictions. On earth the initial spreading of large liquid drops on solid surfaces is always dominated by gravity; in this demonstration the effect of gravity is greatly reduced so that surface energy forces are the controlling factor.

Bourgeois, S. V.↗
NASA NTRS1983

ISEE/IMP observations of simultaneous upstream ion events

Propagation of upstream energetic (50-200 keV) ions is analyzed in sixteen events observed simultaneously by solid state detectors on ISEE 3 at about 200 earth radii and on IMP 8 at about 35 earth radii from the earth. Conclusions are based on comparisons of the pitch angle distributions observed at the two spacecraft and transformed into the solar wind frame. They are beamlike at ISEE 3 and are confined to the outward hemisphere. When IMP 8 is furthest from the bow shock, they are also usually beamlike, or hemispheric. However, when IMP 8 is closer to the bow shock, pancakelike distributions are observed. This systematic variation in the IMP 8 pitch angle distributions delimits a scattering region l less than about 15 earth radii upstream of the earth's bow shock (l measured along the interplanetary magnetic field) that dominates ion propagation, influences the global distribution of fluxes in the foreshock, and may play a role in acceleration of the ions. When IMP 8 is beyond l of about 15 earth radii the propagation appears to be essentially scatter-free between IMP 8 and ISEE 3; this is deduced from the absence of earthward fluxes at IMP 8 as well as the tendency for the spin-averaged fluxes to be comparable at the two spacecraft.

Mitchell, D. G.↗
NASA NTRS1985

Hypervelocity impacts on Skylab 4/Apollo windows

The three largest Skylab 4 Command Module windows that were exposed for 84 days to space were optically scanned for impact features as small as 30 microns in diameter. This scanning effort which was carried out at an opptical magnification of 35x, detected features approximately three times smaller than were found in the original 5x scanning effort over the entire window surface. Some 289 features were recorded from the 35x scan for later detailed analyses. Sixty of the largest and most promising features were cored from the windows for SEM and energy-dispersive X-ray spectrometer (EDS) analysis. Twenty-six of the cores contained craters with glassy pits, and of these, fourteen were found to contain strikingly obvious liners coating the interior of the glassy pit. The six largest features cored from the windows do not have a central glassy pit which leaves their previously reported hypervelocity origin in some doubt. The remaining twenty-eight features that were cored from the windows show no clear evidence for a hypervelocity origin and evidence available at this time is insufficient to identify an origin in Earth orbit or as ground damage. The EDS analysis of six of the seven liners that were examined show detectable aluminum in the liner or lip of the glassy pit. The source of aluminum is most probably an Earth orbiting population of aluminum oxide spherules, exhaust from solid rocket motors.

Clanton, U. S.↗
NASA NTRS1985

Volatiles on satellites of the outer solar system

Molecules of cosmochemically abundant elements can act as volatiles and hence play a dominant role in the climatic and surficial evolution of solid bodies. Examples on terrestrial planets are H2O on Earth and H2O and CO2 on Mars. Analogous processes in the outer solar system focussing on CH4, its associated hydrocarbons, and N2 on Titan and Triton, the large moons of Saturn and Neptune were explored. A kilometer-deep C2H6-CH4 ocean was proposed for the surface of Titan to reconcile data on the lower atmosphere with understanding of the photochemical conversion of methane to heavier hydrocarbons. If such ocean exists, then it has dissolved in it an amount of N2 equal to the present atmospheric abundance. Since N2 contributes with CH4 a substantial greenhouse effect, the atmospheric physical and chemical characteristics are strongly coupled to those of the ocean, which change with time as methane is photolyzed in the stratosphere. Some relationship exists to the runaway greenhouse model for primordial Venus and the possible climatic implications of the buffering of Earth's atmospheric CO2 by the oceans. Two important diagnostics, measurable in Titan's atmosphere, of the conditions under which icy satellites formed are the abundances of noble gases and the CHd/CH4 radio. Both of these indicators have been altered during the evolution of Titan's surface-atmosphere system, the former by interaction with the ocean and the latter by progressive photolysis of methane into heavier hydrocarbons. The physical state and composition of volatiles on the surface of Triton is controversial, but plausibly could include CH4 N2 and perhaps CO. If condensed CH4 and N2 are widespread, their transformation to and from the vapor phase dominates the surface energy balance with sunlight. The extreme seasonal modulation of subsolar latitude on Triton is thus primarily expressed by volatile transport rather than large teperature changes, with possibly drastic observational consequences. The presence of two volatile species differing greatly in their vapor pressures make Triton a crude analog of Mars. Triton might be more appropriately regarded as a deep-freeze version of Titan.

Lunine, J. I.↗
NASA NTRS1984

A circumstellar disk around Beta Pictoris

A circumstellar disk has been observed optically around the fourth-magnitude star Beta Pictoris. First detected in the infrared by the Infrared Astronomy Satellite last year, the disk is seen to extend to more than 400 astronomical units from the star, or more than twice the distance measured in the infrared by the Infrared Astronomy Satellite. The disk is presented to earth almost edge-on and is composed of solid particles in nearly coplanar orbits. The observed change in surface brightness with distance from the star implies that the mass density of the disk falls off with approximately the third power of the radius. Because the circumstellar material is in the form of a highly flattened disk rather than a spherical shell, it is presumed to be associated with planet formation. It seems likely that the system is relatively young and that planet formation either is occurring now around Beta Pictoris or has recently been completed.

Smith, B. A.↗
NASA NTRS1994

Solid surface wetting and the deployment of drops in microgravity

The complete or partial deployment of liquid samples in low gravity is primarily influenced by the interfacial properties of the specific liquid and solid materials used because the overwhelming bias of the Earth gravitational acceleration is removed. This study addresses the engineering aspects of injecting and deploying drops of prescribed volume into an acoustic positioning chamber in microgravity. The specific problems of interest are the design, testing, and implementation of injector tips to be used in a simultaneously retracting dual-injector system in the Drop Physics Module microgravity experiment facility. Prior to release, the liquid to be deployed must be retained within a restricted area at the very end of the injectors under dynamic stimuli from the continuous injection flow as well as from the stepped motion of the injectors. The final released drop must have a well determined volume and negligible residual linear or angular momentum. The outcome of Earth-based short-duration low gravity experiments had been the selection of two types of injector tips which were flown as back-up parts. They were successfully utilized during the USML-1 Spacelab mission as the primary tips. The combination of a larger contact surface, liquid pinning with a sharp edge, and selective coating of strategic tip surfaces with a non-wetting compound has allowed a significant increase in the success rate of deployment of simple and compound drops of aqueous solutions of glycerol and silicone oil. The diameter of the samples studied in the Drop Physics Module range between 0.3 and 2.7 cm. The tests conducted on-orbit with a manually operated small device have allowed the calibration of the volume deployed for a few drop sizes. The design for improved tips to be used during the next USML flight is based on these results.

Trinh, E. H.↗