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EXOS Software

Lyndon B. Johnson Space Center, Houston, Texas An improved version of EXOS software allows for the modeling of fabrics, mixtures, and porous materials, and also provides the ability to accept hex mesh geometries. The code employs a novel numerical method, a hybrid particle finite element approach, as well as particles and elements in tandem, each modeling distinct aspects of the physics. Ellipsoidal particles are used to model contact-impact and volumetric thermomechanical response (Euler parameters provide a singularity-free description of particle rotations). Elements are used to model “strength” effects; namely, tensile inter-particle forces and elastic-plastic deviatoric deformation.

Posted in: Briefs, TSP, Electronics & Computers, Coatings & Adhesives

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Using Paraffin Phase Change Material to Make Optical Communication-Type Payloads Thermally Self-Sufficient for Operation in Orion Crew Module

Goddard Space Flight Center, Greenbelt, Maryland The Orion Crew Module has a pressurized cabin of approximately 20 m3 in volume. There are a number of cold plates within the Crew Module for thermal management. An optical communication type of payload consists of electronics boxes and modems that dissipate a significant amount of heat during science operation. Generally, such payloads operate for a short term (e.g., up to one hour). If these heat-dissipating components are flown inside the Crew Module, they require heat rejection to the cold plates in the Crew Module. The waste heat is transported from the cold plate to thermal radiators located outside the Orion spacecraft. This makes such a payload thermally dependent on the Crew Module cold plates.

Posted in: Briefs, TSP

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Smart MMOD Thermal Blanket

A spacer is added to standard thermal blankets to improve MMOD shielding. Lyndon B. Johnson Space Center, Houston, Texas This innovation provides for significantly improved protection from micrometeoroid and orbital debris (MMOD) particles, and reliably determines the location, depth, and extent of MMOD impact damage.

Posted in: Briefs, TSP

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Using Black Polyimide/Kevlar as a Metering Structure Multi-Layer Insulation (MLI)

This is used as an inner cover for minimizing stray light and providing micrometeoroid protection. Goddard Space Flight Center, Greenbelt, Maryland, Metering structures of remote sensing instruments often have large openings or access holes. Shear panels that are X-shaped, such as those proposed for the Neutron Star Interior Composition Explorer (NICER), generally consist of C-channels and L-brackets to minimize structural distortion. This type of metering structure has large openings on the sides. Structural panels that have large access holes, such as those studied for the Landsat Operational Land Imager (OLI), generally consist of aluminum honeycomb panels with composite facesheets. Both types of metering structure require multilayer insulation (MLI) blankets to shield the internal components such as optics from sunlight and Earth albedo, and to minimize heat loss to 3K space by radiation. The issues of conventional MLI blankets for these metering structures include MLI sagging, stray light, and risk of micrometeoroid damage to optics.

Posted in: Briefs, TSP

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Surface-Modified Nanoparticles Made From High-Molecular-Weight Carboxylic Acids

Starting materials include aluminum oxy hydroxides pretreated with low molecular-weight carboxylic acids. Nanoparticles Made From High-Molecular-Weight Carboxylic Acids An improved class of alumoxanes and a method of synthesizing them have been invented. Alumoxanes are aluminum oxy hydroxide particles that have been modified with compounds containing carboxylic acid groups. For typical applications in which alumoxanes are required to be compatible with polymers, it is desirable that the modifying compounds be carboxylic acids that have high molecular weights (>500 Daltons) and/or are somewhat hydrophobic (characterized by solubility <5% in boiling water). Heretofore, the hydrophobicity of such compounds has made it difficult or impossible to synthesize alumoxanes in sufficiently high yields in acceptably short reaction times, and the alumoxane products have exhibited nonuniformities, both within and between batches. The present invention overcomes these shortcomings of prior approaches to synthesis of alumoxanes.

Posted in: Briefs, TSP

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NASA PS400 High-Temperature Solid Lubricant Coating

The material provides low friction and wear over a wide temperature range. John H. Glenn Research Center, Cleveland, Ohio NASA has an ongoing need for high-temperature solid lubricant coatings to reduce friction and wear in turbine engines, rocket engines, and other mechanical systems. Such lubricants must be thermally and chemically stable in air, vacuum, and reducing environments like hydrogen. Traditional lubricants like oil, grease, and PTFE (Polytetrafluoroethylene), and even more exotic solid lubricants like graphite and molybdenum disulphide, lack such capabilities. The key problem is to identify and formulate a material that possesses good mechanical properties, long-term environmental durability, and acceptable friction and wear-reducing characteristics while being practical to apply to bearings, seals, and other mechanical components.

Posted in: Briefs, TSP

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Triple Orthogonal Disk Polymer Discrete Space for Cryogenic Feedline Insulation

A new material provides a superior, robust insulation for cryogenic feed lines. John H. Glenn Research Center, Cleveland, Ohio NASA vehicles using cryogenic propellants and systems need improved cryogenic storage and transfer, including insulation for cryogenic transfer/feed lines. Wrapped multi-layer insulation (WMLI) is an innovative, next-generation, high-performance multilayer insulation designed specifically for cryogenic plumbing systems. WMLI uses Quest Thermal Group’s Discrete Spacer Technology to precisely control layer spacing, layer density, and minimize system heat flux. A customized discrete spacer, the Triple Orthogonal Disk (TOD) spacer, was designed, micromolded, and tested, and provides significantly lower heat leak than current state-of-the-art MLI insulation.

Posted in: Briefs, TSP

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