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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Generative learning of densities on manifolds

A generative modeling framework is proposed that combines diffusion models and manifold learning to efficiently sample data densities on manifolds. The approach utilizes Diffusion Maps to uncover possible low-dimensional underlying (latent) spaces in the high-dimensional data (ambient) space. Two approaches for sampling from the latent data density are described. The first is a score-based diffusion model, which is trained to map a standard normal distribution to the latent data distribution using a neural network. The second one involves solving an Itô stochastic differential equation in the latent space. Additional realizations of the data are generated by lifting the samples back to the ambient space using Double Diffusion Maps , a recently introduced technique typically employed in studying dynamical system reduction; here the focus lies in sampling densities rather than system dynamics. The proposed approaches enable sampling high dimensional data densities restricted to low-dimensional, a priori unknown manifolds. The efficacy of the proposed framework is demonstrated through a benchmark problem and a material with multiscale structure.

Double diffusion maps↗
NASA NTRS1993

On-orbit servicing for USAF space missions: A phased development approach

On-orbit servicing has been studied for years by the U.S. Air Force Space Systems Division--which recently cosponsored the Space Assembly, Maintenance, and Servicing Study with NASA and SDIO; but an Air force servicing program has yet to emerge. The Air Force has a limited set of servicing requirements, and the practices of 'pipelining' (incremental improvements to a space vehicle series) and orbital sparing provide many similar benefits. It is postulated that an Air Force Program will be initiated in response to a new critical mission requirement that calls for a spacecraft with the operational character of a Servicer, which will evolve into a servicing program. Such a requirement may be emerging. The Air Force organizations charged with on-orbit test safety for the Department of Defense are concerned with the hazard from uncontrolled reentry of low Earth orbit test spacecraft, which are increasing in number. Analysis and observations of actual reentries show that debris reaches the Earth's surface. A phased development of a system to remove these spacecraft from orbit can evolve into a servicing program.

Shanney, Bill↗
NASA NTRS2020

Improvement of Shelf Life for Space Food Through a Hurdle Approach

The processed and prepackaged spaceflight food system is a critical human support system for manned space flights. As missions extend longer and farther from Earth over the next 20 years, strategies to stabilize the nutritional and sensory quality of food must be identified. For a mission to Mars, the space foods themselves must maintain quality for up to 5 years to align with cargo prepositioning scenarios. Optimizing the food system to achieve a 5-year shelf life mitigates the risk of an inadequate food system during extended missions. Because previous attempts to determine a singular pathway to a 5-year shelf life for food were unsuccessful, this investigation combines several approaches, based on science, technological advancement, and past empirical evidence, that will define the prepackaged food system for long duration missions. This study supports the Advanced Food Technology strategic planning process by identifying food processing, packaging, and storage technologies that will be required for exploration missions and the extent that they must be implemented to achieve a 5-year shelf life for the entire food system.

Sirmons, T. A.↗
NASA NTRS1987

Verification of large beam-type space structures

The verification approach of large beam type space structures is verified. The proposed verification approach consists of two parts. The first part is to remove the gravity effect on the tested substructure and to identify the on-orbit dynamic characteristics of the substructure by using the measurements of the ground test. A scaling law is also established to define the critical length of the structure which can be tested in 1-g field without incurring a buckling problem. The second part is to develop an adequate scaling law to extrapolate the dynamic characteristics of the prototype structure by using results from the substructure. The verification approaches are demonstrated on two typical structural configurations, the feed support structure of a wrap-rip antenna and a candidate shuttle flight experiment. The results indicate that it is practical to verify the on-orbit dynamic characteristics of these structures by using the proposed approach.

Shih, Choon-Foo↗
NASA NTRS1983

Control structure interactions in large space structures Analysis using energy approach

A simple energy approach to study the problem of control structure interactions in large space structures is presented. For the illustrative cases of free-free beam and free rectangular plate, the vibrational energy imparted during operation of constant and pulsed thrusters is found in a nondimensional form. Then based on a parametric study, suggestions are made on the choice of the thruster location and parameters to minimize the control structure interactions.

Shrivastava, S. K.↗
NASA NTRS1999

Simulated Atomic Fission Engine (S.A.F.E)

This paper presents viewgraphs of S.A.F.E. (Simulated Atomic Fission Engine). The topics include: 1) Why Space Fission Propulsion? 2) History of Fission System Development; 3) New Approach to Space Fission Propulsion System Development; 4) Propulsion Flight Demonstrator Schematic Flight Configuration; 5) Ongoing Propellant Energy Source Tests; 6) First Generation Propulsion System Status; 7) Tungsten Fuel Pin Simulator Tests; 8) Full Module Test (High Efficiency Mode); and 9) First Generation Propulsion Flight Demonstrator Status.

VanDyke, Melissa↗
NASA NTRS2019

eddy Users Manual

eddy is a collection of tools - nonlinear solvers, meshing, post-processing, visualization, optimization, etc. - for performing scale-resolving simulations of multi-physics applications. The framework is designed to enable advanced R&D on a variety of topics by leveraging a mature capability for scale resolving simulations, and simultaneously be an appropriate tool for application analysis and support. Currently, eddy is at a relatively low technical readiness level (TRL), and users and developers should maintain appropriate expectations. The technical details behind eddy are outlined in several publications which can be consulted for more information [1–10]. The solvers are built around an unstructured high-order capability, and heavily utilize the tensor product sum-factorization approach for efficiency. The unsteady formulation utilizes a fully implicit space-time approach with a matrix-free Newton- Krylov method. A primitive steady-state solver is available for testing purposes, but is not expected to converge for all but simple verification cases. The Navier-Stokes fluid solvers do not support either RANS or hybrid-RANS capability, only LES and wall-modeled LES approaches. All of the solvers within eddy support three modes of operation: a primal solve of the full nonlinear problem, and two linearization approaches of the primal solve - the ad joint and the tangent solution. Details on how to select and use these three modes are outlined in Sec. 3.

Murman, Scott M.↗
NASA NTRS1979

Evaluation criteria for commercially oriented materials processing in space proposals

An approach and criteria for evaluating NASA funded experiments and demonstrations which have commercial potential were developed. Methods for insuring quick initial screening of commercial proposals are presented. Recommendations are given for modifying the current evaluation approach. New criteria for evaluating commercially orientated materials processing in space (MPS) proposals are introduced. The process for selection of qualified individuals to evaluate the phases of this approach and criteria is considered and guidelines are set for its implementation.

Moore, W. F.↗
NASA NTRS2004

The Vision for Space Exploration

With last year's budget, NASA released a new Strategic Plan outlining a new approach to space exploration using a 'building block' strategy to explore scientifically valuable destinations across our solar system. At the same time that we released the Strategic Plan, our Nation and the NASA family also suffered the loss of the seven brave astronauts aboard the Space Shuttle Columbia. The report of the Columbia Accident Investigation Board emphasized the need for a clearer direction from which to drive NASA's human exploration agenda. On January 14, 2004, the President articulated a new vision for space exploration. You hold in your hands a new, bolder framework for exploring our solar system that builds upon the policy that was announced by the President after months of careful deliberations within the Administration. This plan does not undertake exploration merely for the sake of adventure, however exciting that may be, but seeks answers to profound scientific and philosophical questions, responds to recent discoveries, will put in place revolutionary technologies and capabilities for the future, and will genuinely inspire our Nation, the world, and the next generation. Our aim is to explore in a sustainable, affordable, and flexible manner. We believe the principles and roadmap set down in this document will stand the test of time. Its details will be subject to revision and expansion as new discoveries are made, new technologies are applied, and new challenges are met and overcome. This plan is guided by the Administration's new space exploration policy, 'A Renewed Spirit of Discovery: The President's Vision for U.S. Space Exploration,' a copy of which is provided on the following pages. NASA is releasing this plan simultaneously with NASA's FY 2005 Budget Justification. This plan is fiscally responsible, consistent with the Administration s goal of cutting the budget deficit in half within the next five years. I cannot overstate how much NASA will change in the coming years as this plan is implemented. I also cannot overstate how profound the rewards will be on this new course. With the support of Congress, the science community, the NASA civil and contractor workforce, and most importantly, the American public, we will embark on this very exciting future. When Christopher Columbus made his voyages across the Atlantic in the 15th and 16th centuries, his ships carried the inscription 'Following the light of the sun, we left the Old World.' I look forward to joining you as we follow the light of the planets and the stars into the new worlds of the 21st century.

Source record↗
DOE OSTI2025

Spectrally accelerated edge and scrape-off layer gyrokinetic turbulence simulations

This paper presents the first gyrokinetic (GK) simulations of edge and scrape-off layer (SOL) turbulence accelerated by a velocity-space spectral approach in the full-f GK code GENE-X. Building upon the original grid velocity-space discretization, we derive and implement a new spectral formulation and verify the numerical implementation using the method of manufactured solution. We conduct a series of spectral turbulence simulations focusing on the TCV-X21 reference case (Oliveira et al., 2022 [26]) and compare these results with previously validated grid simulations (Ulbl et al., 2023 [25]). The spectral approach reproduces the outboard midplane (OMP) profiles (density, temperature, and radial electric field), dominated by trapped electron mode (TEM) turbulence, with excellent agreement and significantly lower velocity-space resolution. As a consequence, the spectral approach reduces the computational cost (CPUh) by at least an order of magnitude, of approximately 50 for the TCV-X21 case. This enables high-fidelity GK simulations to be performed within a few days on modern CPU-based supercomputers for medium-sized devices and establishes GENE-X as a powerful tool for studying edge and SOL turbulence, moving towards reactor-relevant devices like ITER.

Gyrokinetic↗
NASA NTRS1987

On the dynamics of manipulators in space using the virtual manipulator approach

A virtual manipulator (VM) concept has been developed recently for the modeling of manipulators working in space. The authors show that the VM facilitates planning and control of the motions of manipulators mounted on spacecraft, minimizing the degrading consequences of manipulator/vehicle dynamic interactions.

Vafa, Z.↗
NASA NTRS2012

Concepts for a Shroud or Propellant Tank Derived Deep Space Habitat

Long duration human spaceflight missions beyond Low Earth Orbit will require much larger spacecraft than capsules such as the Russian Soyuz or American Orion Multi-Purpose Crew Vehicle. A concept spacecraft under development is the Deep Space Habitat, with volumes approaching that of space stations such as Skylab, Mir, and the International Space Station. This paper explores several concepts for Deep Space Habitats constructed from a launch vehicle shroud or propellant tank. It also recommends future research using mockups and prototypes to validate the size and crew station capabilities of such a habitat. Keywords: Exploration, space station, lunar outpost, NEA, habitat, long duration, deep space habitat, shroud, propellant tank.

Howard, Robert L.↗
NASA NTRS2007

Image Analysis Based on Soft Computing and Applied on Space Shuttle During the Liftoff Process

Imaging techniques based on Soft Computing (SC) and developed at Kennedy Space Center (KSC) have been implemented on a variety of prototype applications related to the safety operation of the Space Shuttle during the liftoff process. These SC-based prototype applications include detection and tracking of moving Foreign Objects Debris (FOD) during the Space Shuttle liftoff, visual anomaly detection on slidewires used in the emergency egress system for the Space Shuttle at the laJlIlch pad, and visual detection of distant birds approaching the Space Shuttle launch pad. This SC-based image analysis capability developed at KSC was also used to analyze images acquired during the accident of the Space Shuttle Columbia and estimate the trajectory and velocity of the foam that caused the accident.

Dominquez, Jesus A.↗
NASA NTRS2011

Small Rocket/Spacecraft Technology (SMART) Platform

The NASA Goddard Space Flight Center (GSFC) and the Department of Defense Operationally Responsive Space (ORS) Office are exercising a multi-year collaborative agreement focused on a redefinition of the way space missions are designed and implemented. A much faster, leaner and effective approach to space flight requires the concerted effort of a multi-agency team tasked with developing the building blocks, both programmatically and technologically, to ultimately achieve flights within 7-days from mission call-up. For NASA, rapid mission implementations represent an opportunity to find creative ways for reducing mission life-cycle times with the resulting savings in cost. This in tum enables a class of missions catering to a broader audience of science participants, from universities to private and national laboratory researchers. To that end, the SMART (Small Rocket/Spacecraft Technology) micro-spacecraft prototype demonstrates an advanced avionics system with integrated GPS capability, high-speed plug-and-playable interfaces, legacy interfaces, inertial navigation, a modular reconfigurable structure, tunable thermal technology, and a number of instruments for environmental and optical sensing. Although SMART was first launched inside a sounding rocket, it is designed as a free-flyer.

Esper, Jaime↗
NASA NTRS1974

Degradation of learned skills. Static practice effectiveness for visual approach and landing skill retention

The effectivess of an improved static retraining method was evaluated for a simulated space vehicle approach and landing under instrument and visual flight conditions. Experienced pilots were trained and then tested after 4 months without flying to compare their performance using the improved method with three methods previously evaluated. Use of the improved static retraining method resulted in no practical or significant skill degradation and was found to be even more effective than methods using a dynamic presentation of visual cues. The results suggested that properly structured open loop methods of flight control task retraining are feasible.

Sitterley, T. E.↗
NASA NTRS1985

Earth based approaches to enhancing the health and safety of space operations

This paper provides an overview of the current state of our earth based knowledge of space safety hazards; identification of several key areas of concern for space operations; and proposed approaches to providing technology enhancement and information needed to improve the health and safety to those conducting space operations. Included are a review of the identified hazards for space oeprations by hazard classification; a summarization of the information currently available on space experiences and an assessment of potential hazards for long duration spaceflight; a discussion of potential failure modes and their significance for Space Station work: and an assessment of current work which indicates additional research and experimentation which can only be accomplished in actual space missions.

Koller, A. M., Jr.↗
NASA NTRS1990

Space Station Freedom - Configuration management approach to supporting concurrent engineering and total quality management

Some experiences of NASA configuration management in providing concurrent engineering support to the Space Station Freedom program for the achievement of life cycle benefits and total quality are discussed. Three change decision experiences involving tracing requirements and automated information systems of the electrical power system are described. The potential benefits of concurrent engineering and total quality management include improved operational effectiveness, reduced logistics and support requirements, prevention of schedule slippages, and life cycle cost savings. It is shown how configuration management can influence the benefits attained through disciplined approaches and innovations that compel consideration of all the technical elements of engineering and quality factors that apply to the program development, transition to operations and in operations. Configuration management experiences involving the Space Station program's tiered management structure, the work package contractors, international partners, and the participating NASA centers are discussed.

Gavert, Raymond B.↗