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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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Adjoint-Based Minimization of X-59 Sonic Boom Noise Via Control Surfaces
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Monte-Carlo Analysis of Minimal Thermocouple Depths using Icarus
Icarus is a three-dimensional, unstructured, finite-volume material response solver developed at NASA Ames Research Center \cite{Schulz_2017} and has been verified against other NASA material response tools like FIAT, which have a long history of successfully designing thermal protection system (TPS). Icarus solves a set of conservation equations for mass and energy and uses Darcy’s Law in place of momentum conservation. An ecosystem of material response tools has been built around a general-purposed Icarus library that in addition to the typical material response analysis also supports TPS sizing (1-D and multi-dimensional), uncertainty quantification, and has been successfully integrated into a multi-physics architecture built around US3D \cite{Schroeder_2021}. In this paper, a brief overview of Icarus and its capabilities will be presented using an illustrative Monte Carlo analysis of the one-dimensional, in-depth material response of a representative Dragonfly trajectory.
Design of a Minimal di-Nickel Hydrogenase Peptide
The most ancient processes for energy production in the evolution of life involve the reversible oxidation of molecular hydrogen by hydrogenase. Extant hydrogenase enzymes are complex, comprising hundreds of amino acids and multiple cofactors. We designed a 13 amino acid nickel-binding peptide capable of robustly producing molecular hydrogen from protons under a wide variety of conditions. The peptide forms a di-nickel cluster structurally analogous to a Ni-Fe cluster in [NiFe]-hydrogenase and the Ni-Ni cluster in acetyl-CoA synthase (ACS), two ancient, extant proteins central to metabolism. These experimental results clearly demonstrate that modern enzymes, despite their enormous complexity, likely evolved from simple peptide precursors on early Earth. One Sentence Summary: Small metal-binding peptides were the likely precursors of modern enzymes.
Integrated Systems Engineering, Safety, Reliability and Risk Management – Minimizing Black Swan Events
This paper examines key barriers that can possibly inhibit safe and reliable mission execution and, in the worst case, result in loss of human life due to many unknown contributory factors that can lead to Black Swan events. Some of the representative contributory factors include decision errors, overconfidence and a host of common causes including cultural and human factors. Decisions are always easy to criticize in hindsight when more information is available after a major accident. Depending on the type and complexity of the project and/or mission, the catastrophic risks of drifting into failure can be alleviated by implementing uniquely and strategically tailored Integrated-System-of-Systems, dynamic, risk-informed decision management processes. This paper presents some of the lessons learned from James Webb Space Telescope (JWST), NASA’s Human Space Flight program, and industry that provide motivation to organizations working on mega-complex missions to prudently accomplish targeted mission success. These lessons are important for future human Lunar, Mars and Beyond missions planned to be pursued by NASA through a public-private partnership using nimble but effective safety-conscious, proven sound engineering practices including implementation of integrated risk mitigation practices.
Dynamically Rendering Rough Terrain with Minimal Memory Overhead
Rendering highly detailed terrain is a process with the potential to consume a great deal of a computer’s random access memory (RAM). In a browser-based application, this resource is limited even further, leading to the necessity to use alternative methods of rendering the large amount of data needed for high detail. This report describes one such method that places the onus of rendering on the speed of the graphics processing unit (GPU) rather than on the computer’s memory. By removing attribute buffers, which contribute greatly to memory costs, from the rendering pipeline and generating the requisite attributes on the fly using a heightmap texture instead, it is estimated that memory usage can be cut down to one-sixth that of the previous method.
Waste Container Filtration To Minimize Microbial Escape During Long-Term Storage On Mars
In the search for life on Mars, keeping its surface pristine and free of microbes due to human presence is of utmost importance. Astronauts will use emptied logistics containers during their Martian stay to store waste. These containers will be left on the planet’s surface and are a potential source of microbial contamination. It is desired for these containers to be free from leaks for a minimum of 50 years. If leaks do occur a likely location will be at the port. At this location the mating surfaces will be sealed using a flexible gasket material like a thin metal or a polymer. Eventually these seals will fail. To mitigate these effects, a particulate filter can be employed to equilibrate the pressure between the Martin environment and inside the container. To meet planetary protection requirements, the filter can only allow particulates smaller than 0.2 um diameter to pass. This paper discusses why a particulate filter may be needed and how such a filter would be tested to survive and operate in the harsh Martian environment.
Waste Container Filtration to Minimize Microbial Escape During Long-Term Storage on Mars
In the search for life on Mars, keeping its surface pristine and free of microbes due to human presence is of utmost importance. Astronauts will use emptied logistics containers during their Mars stay to store waste. These containers will be left on the planet’s surface and are a potential source of microorganism contamination. It is desired for these containers to be free from leaks for a minimum of 50 years. If leaks do occur, a likely location will be at any ports. At these locations the mating surfaces will be sealed using a flexible gasket material like a thin metal or a polymer. Eventually these seals will fail. To mitigate these effects, a particulate filter can be employed to equilibrate the pressure between the Martin environment and inside the container. To meet planetary protection requirements, the filter can only allow particulates smaller than 0.2 m diameter to pass. This paper discusses why a particulate filter may be needed and how such a filter could be tested to survive and operate in the harsh Martian environment.
Sound Absorption Properties of Additively Manufactured Porous Materials With Minimal Surface Pore Geometries
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Waste Container Filtration to Minimize Microbial Escape During Long-Term Storage on Mars
In the search for life on Mars, keeping its surface pristine and free of microbes due to human presence is of utmost importance. Astronauts will use emptied logistics containers during their Mars stay to store waste. These containers will be left on the planet’s surface and are a potential source of microorganism contamination. It is desired for these containers to be free from leaks for a minimum of 50 years. If leaks do occur, a likely location will be at any ports. At these locations the mating surfaces will be sealed using a flexible gasket material like a thin metal or a polymer. Eventually these seals will fail. To mitigate these effects, a particulate filter can be employed to equilibrate the pressure between the Martin environment and inside the container. To meet planetary protection requirements, the filter can only allow particulates smaller than 0.2 μm diameter to pass. This paper discusses why a particulate filter may be needed and how such a filter could be tested to survive and operate in the harsh Martian environment.
Minimally Invasive Wearables for Assessing Astronauts’ Physiological Response to Space Stressor
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Sonic Boom Ground Noise Minimization Via the Adjoint Method
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Actuator energy and drag minimization of a blended-wing-body with variable-camber continuous trailing-edge flaps
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Minimal differential lateral acceleration configurations for starshade stationkeeping in exoplanet direct imaging
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A Passive Microwave Retrieval Algorithm with Minimal View-Angle Bias: Application to the TEMPEST-D CubeSat Mission
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Protein cost minimization promotes the emergence of coenzyme redundancy
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Recent anthropogenic increases in SO 2 from Asia have minimal impact on stratospheric aerosol
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On complexity of trellis structure of linear block codes
The trellis structure of linear block codes (LBCs) is discussed. The state and branch complexities of a trellis diagram (TD) for a LBC is investigated. The TD with the minimum number of states is said to be minimal. The branch complexity of a minimal TD for a LBC is expressed in terms of the dimensions of specific subcodes of the given code. Then upper and lower bounds are derived on the number of states of a minimal TD for a LBC, and it is shown that a cyclic (or shortened cyclic) code is the worst in terms of the state complexity among the LBCs of the same length and dimension. Furthermore, it is shown that the structural complexity of a minimal TD for a LBC depends on the order of its bit positions. This fact suggests that an appropriate permutation of the bit positions of a code may result in an equivalent code with a much simpler minimal TD. Boolean polynomial representation of codewords of a LBC is also considered. This representation helps in study of the trellis structure of the code. Boolean polynomial representation of a code is applied to construct its minimal TD. Particularly, the construction of minimal trellises for Reed-Muller codes and the extended and permuted binary primitive BCH codes which contain Reed-Muller as subcodes is emphasized. Finally, the structural complexity of minimal trellises for the extended and permuted, and double-error-correcting BCH codes is analyzed and presented. It is shown that these codes have relatively simple trellis structure and hence can be decoded with the Viterbi decoding algorithm.