SEARCH · Engineering Papers

Results for “closest primitives”

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.

SourceResearch connectionFrom yearThrough year

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

3 records

All sources NASA NTRS DOE OSTI

DOE OSTI2025

Exact signed distance fields using parallel Fast Sweeping Method

Signed distance fields are often used in multiphysics simulations to track material interfaces. We present a simple methodology based on the fast sweeping method to generate the exact signed distance from triangular meshes and linear paths on Cartesian grids. The methodology propagates the closest primitive to the boundary to the rest of the domain following the characteristics. A local upwind criterion is used to decide between the new and existing closest primitive at each grid point while capturing the correct sign of the global function. The methodology has optimal computational complexity and runs efficiently in distributed-memory architectures. We include 2D and 3D test cases along with a resolution study up to 0.512 trillion zones and 1,000 computer cores. The solution strategy can also be applied to other types of meshes or collections of primitives.

97 MATHEMATICS AND COMPUTING↗

NASA NTRS2005

Experimental Petrology of the Basaltic Shergottite Yamato 980459: Implications for the Thermal Structure of the Martian Mantle

Yamato 980459 (Y98) is an olivine-phyric basaltic shergottite composed of 48% pyroxene, 26% olivine, 25% mesostasis, and 1% other minerals. Unlike the other Martian basalts, it contains no plagioclase. Olivine in Y98 is the most magnesian of all Martian meteorites. Thus Y98 is believed to be the most primitive and its composition may be the closest to a primary or direct melt of the Martian mantle. As such, it provides a very useful probe of the mineralogy and depth of its mantle source region. Toward this end, we are conducting crystallization experiments on a synthetic Y98 composition at Martian mantle pressures and temperatures.

Dalton, H. A.↗

NASA NTRS1990

On-orbit assembly/servicing task definition study

The OEXP vehicles being envisioned to carry out the Presidential space goals of a lunar outpost and human exploration of Mars will require on-orbit assembly, refurbishment, checkout, and launch. The On-orbit Assembly/Servicing Task Definition Study applies the space vehicle processing experience and procedures archives resident at NASA's Kennedy Space Center (KSC) to determine the task flows, and resources/facilities necessary to process the OEXP vehicles at Space Station Freedom (SSF). This data base is examined to find the closest analogies to OEXP vehicle components and assembly/refurbishment tasks. Transition tables are generated to provide traceability from KSC hardware processing experience to analogous on-orbit processing of the OEXP vehicles. Iterations in which the task flows are broken down into realistic extravehicular activity (EVA) primitive subtasks and times, and to apply automation and robotic technology to reduce crew risks and minimize EVA time, will enhance the value and accuracy of the predicted flows. These processing scenarios and the resulting resource/facility requirements are used to determine impacts of SSF, resulting in change requests to SSF requirements for provision of 'hooks and scars' to evolve the assembly complete Space Station into a transportation node. Study results to date include assembly analysis of the Martin Marietta Phobos Gateway Vehicle, refurbishment analysis of the Martin Marietta Lunar Evolution Piloted and Cargo Vehicles, and assembly analysis of the Boeing Mars Evolution Vehicle. The results of this study will be accumulated into the vehicle processing operations data base for subsequent modeling, life cycle cost, vehicle growth, and SSF impact analysis.

Vargo, Rick↗