Search NASA⌕ Search

SEARCH · Search NASA

Results for “Space Perception”

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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

Perceived visual speed constrained by image segmentation

Little is known about how or where the visual system parses the visual scene into objects or surfaces. However, it is generally assumed that the segmentation and grouping of pieces of the image into discrete entities is due to 'later' processing stages, after the 'early' processing of the visual image by local mechanisms selective for attributes such as colour, orientation, depth, and motion. Speed perception is also thought to be mediated by early mechanisms tuned for speed. Here we show that manipulating the way in which an image is parsed changes the way in which local speed information is processed. Manipulations that cause multiple stimuli to appear as parts of a single patch degrade speed discrimination, whereas manipulations that perceptually divide a single large stimulus into parts improve discrimination. These results indicate that processes as early as speed perception may be constrained by the parsing of the visual image into discrete entities.

NASA Discipline Neuroscience↗
DOE OSTI2011

'Who Thinks Abstractly?': Quantum Theory and the Architecture of Physical Concepts

Beginning with its introduction by W. Heisenberg, quantum mechanics was often seen as an overly abstract theory, mathematically and physically, vis-a-vis classical physics or relativity. This perception was amplified by the fact that, while the quantum-mechanical formalism provided effective predictive algorithms for the probabilistic predictions concerning quantum experiments, it appeared unable to describe, even by way idealization, quantum processes themselves in space and time, in the way classical mechanics or relativity did. The aim of the present paper is to reconsider the nature of mathematical and physical abstraction in modern physics by offering an analysis of the concept of ''physical fact'' and of the concept of 'physical concept', in part by following G. W. F. Hegel's and G. Deleuze's arguments concerning the nature of conceptual thinking. In classical physics, relativity, and quantum physics alike, I argue, physical concepts are defined by the following main features - 1) their multi-component multiplicity; 2) their essential relations to problems; 3) and the interactions between physical, mathematical, and philosophical components within each concept. It is the particular character of these interactions in quantum mechanics, as defined by its essentially predictive (rather than descriptive) nature, that distinguishes it from classical physics and relativity.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1989

Background of the workshop

The long-term effects of the Challenger accident on solar-terrestrial science resulted in the need to examine the near-term missions under development for the next five years. The workshop was organized to seek ideas and opinions about the future of solar-terrestrial flight programs. Included are considerations of all types of space platforms, i.e., balloons, rockets, free flying satellites, and the variety of platforms supported by NASA astronauts. Specific issues include: the establishment of the level of understanding to be accomplished with the completion of the current worldwide program of research in solar-terrestrial sciences; the identification of major questions to be answered by the future solar-terrestrial sciences research program as it might be if initiated within the next ten years; the identification of space capabilities to be available to the future program and provision of input about the Space Physics Division's priorities for using these to accomplish its future scientific program; and mapping a program strategy to accomplish a future program of research in the solar-terrestrial sciences within the research community's perception of capabilities and constraints.

Source record↗
NASA NTRS1992

Space flight and changes in spatial orientation

From a sensory point of view, space flight represents a form of stimulus rearrangement requiring modification of established terrestrial response patterns through central reinterpretation. Evidence of sensory reinterpretation is manifested as postflight modifications of eye/head coordination, locomotor patterns, postural control strategies, and illusory perceptions of self or surround motion in conjunction with head movements. Under normal preflight conditions, the head is stabilized during locomotion, but immediately postflight reduced head stability, coupled with inappropriate eye/head coordination, results in modifications of gait. Postflight postural control exhibits increased dependence on vision which compensates for inappropriate interpretation of otolith and proprioceptive inputs. Eye movements compensatory for perceived self motion, rather than actual head movements have been observed postflight. Overall, the in-flight adaptive modification of head stabilization strategies, changes in head/eye coordination, illusionary motion, and postural control are maladaptive for a return to the terrestrial environment. Appropriate countermeasures for long-duration flights will rely on preflight adaptation and in-flight training.

Reschke, Millard F.↗
NASA NTRS1992

A knowledge based system for scientific data visualization

A knowledge-based system, called visualization tool assistant (VISTA), which was developed to assist scientists in the design of scientific data visualization techniques, is described. The system derives its knowledge from several sources which provide information about data characteristics, visualization primitives, and effective visual perception. The design methodology employed by the system is based on a sequence of transformations which decomposes a data set into a set of data partitions, maps this set of partitions to visualization primitives, and combines these primitives into a composite visualization technique design. Although the primary function of the system is to generate an effective visualization technique design for a given data set by using principles of visual perception the system also allows users to interactively modify the design, and renders the resulting image using a variety of rendering algorithms. The current version of the system primarily supports visualization techniques having applicability in earth and space sciences, although it may easily be extended to include other techniques useful in other disciplines such as computational fluid dynamics, finite-element analysis and medical imaging.

Senay, Hikmet↗
NASA NTRS1998

Gravitropism and development of wild-type and starch-deficient mutants of Arabidopsis during spaceflight

The "starch-statolith" hypothesis has been used by plant physiologists to explain the gravity perception mechanism in higher plants. In order to help resolve some of the controversy associated with ground-based research that has supported this theory, we performed a spaceflight experiment during the January 1997 mission of the Space Shuttle STS-81. Seedlings of wild-type (WT) Arabidopsis, two reduced-starch strains, and a starchless mutant were grown in microgravity and then given a gravity stimulus on a centrifuge. In terms of development in space, germination was greater than 90% for seeds in microgravity, and flight seedlings were smaller (60% in total length) compared to control plants grown on the ground and to control plants on a rotating clinostat. Seedlings grown in space had two structural features that distinguished them from the controls: a greater density of root hairs and an anomalous hypocotyl hook structure. However, the slower growth and morphological changes observed in the flight seedlings may be due to the effects of ethylene present in the spacecraft. Nevertheless, during the flight hypocotyls of WT seedlings responded to a unilateral 60 min stimulus provided by a 1-g centrifuge while those of the starch-deficient strains did not. Thus the strain with the greatest amount of starch responded to the stimulus given in flight and therefore, these data support the starch-statolith model for gravity sensing.

short duration↗
DOE OSTI2020

Detection and Perception of Sound by Eagles and Surrogate Raptors

One overarching objective of this program of study was the accumulation of objective, scientifically valid information relating to auditory performance of bald and golden eagles that may be used to guide the development of acoustic alerting/deterrence technologies intended to discourage encroachment into wind energy air spaces. To that end, analyses aimed at the characterization of sensitivity to sound in bald and golden eagles, along with findings in the supra-threshold, dynamic frequency spaces related to response latencies and amplitudes, leads us to conclude that bald, and golden eagles navigate the same basic working auditory space, as in other known and thus far characterized members of the diurnal raptor family. Specifically, bald and golden eagles, along with other raptor species within the group, operate in an auditory space characterized by a frequency band at least four octaves wide and centered on 2 kHz, with an upper frequency limit between 6 and 10 kHz at 80 dB SPL and a lower frequency limit that almost certainly extends below 0.2 kHz. Consequently, we recommend that signal designers use these data as a guideline in efforts to design effective and efficient acoustic alerting/deterrent systems. It is important to note that signal energy broadcast outside of this frequency band at moderate levels will not contribute to the efficacy of a deterrent but will add an unnecessary fraction to the overall acoustic pollution budget. The importance of this consideration is heightened by contemporaneous concerns related to the transmission of noise broadcast by wind energy farms. In addition, based on analyses of data acquired from red-tailed hawks using the same experimental paradigm and data acquisition system, we conclude that auditory function in the red-tailed hawk is sufficiently like that observed in bald and golden eagles to permit its use as a surrogate species. Response waveforms, threshold-frequency curves, and input-output characteristics match those of eagles closely. It should be noted however, that differences in sensitivity and slightly extended high-frequency limits of hearing should be taken into account when extrapolating findings from one species to the others. Although the inclusion of behavioral tests of red-tailed hawks to acoustic stimuli was beyond the scope of this investigation, future efforts to assess response parameters like signal-type preference and habituation rate will further elucidate their suitability to serve as eagle surrogates in behavioral studies; nonetheless, the species in question are well matched with respect to basic auditory performance. A second essential objective of this program of study was the acoustic characterization of a subset of calls comprising the vocal repertoires of bald and golden eagles that may be used to supplement auditory performance findings in the effort to guide the development of acoustic alerting signals. With regard to that objective, the vocal repertoires of both bald and golden eagle species are rich and varied. While similar in spectrographic structure, distinctive differences are also clear. Generally, golden eagles produce some calls with shorter durations, and similar “sounding” calls exhibit distinctively different spectrographic patterns than those of bald eagles. Both species produce calls that contain a wide variety of nonlinear elements that operate to enhance the rich and varied nature of commonly observed vocal products. Comparison of the average power spectra of commonly observed bald and golden eagle calls with threshold-frequency curves leads to the conclusion that call energies fall within the frequency bounds of hearing. Further, the acoustic energy of calls considered in this report tend to fall into overlapping, but different frequency ranges of the acoustic sensitivity curve. This condition may encourage signal designers to vary the frequency content of acoustic deterrence signals in the field. Finally, preliminary observations relating to the tendencies and proclivities of bald eagles to attend to the acoustic landscape lead to the conclusion that eagles monitor their immediate sound environment assiduously. Individuals respond to a variety of natural and synthetic sound signals reliably and, perhaps most relevant in the context of the engineering of acoustic alerting/deterrence technologies, habituation to most sounds considered in this effort was minimal. These preliminary results, while calling for extended behavioral testing, are promising and set the stage for the exportation of behavioral studies into real world scenarios.

17 WIND ENERGY↗
NASA NTRS1992

Angular relation of axes in perceptual space

The geometry of perceptual space needs to be known to model spatial orientation constancy or to create virtual environments. To examine one main aspect of this geometry, the angular relation between the three spatial axes was measured. Experiments were performed consisting of a perceptual task in which subjects were asked to set independently their apparent vertical and horizontal plane. The visual background provided no other stimuli to serve as optical direction cues. The task was performed in a number of different body tilt positions with pitches and rolls varied in steps of 30 degs. The results clearly show the distortion of orthogonality of the perceptual space for nonupright body positions. Large interindividual differences were found. Deviations from orthogonality up to 25 deg were detected in the pitch as well as in the roll direction. Implications of this nonorthogonality on further studies of spatial perception and on the construction of virtual environments for human interaction is also discussed.

Bucher, Urs↗
NASA NTRS1983

Role of corollary discharge in space constancy

Visual fixation can be maintained in spite of finger pressure on the monocularly viewing eye. The amount of extraocular muscle effort required to counter the eyepress is measured as the secondary deviation of the occluded fellow eye. Using this method, without drugs or neurological lesions, it is shown that corollary discharge (CD) governs perception of position of a luminous point in darkness, that is, an unstructured visual field. CD also controls visuomotor coordination measured with open-loop pointing and the matching of visual and auditory direction in light and in darkness. The incorrectly biased CD is superseded by visual position perception in normal structured environments, a phenomenon called visual capture of Matin. When the structured visual field is extinguished, leaving only a luminous point, gradual release from visual capture and return to the biased CD direction follows after a delay of about 5 sec.

Stark, L.↗
DOE OSTI2019

Saddle point approaches in strong field physics and generation of attosecond pulses

Attoscience is the emerging field that accesses the fastest electronic processes occurring at the atomic and molecular length scales with attosecond (1 as = 10 –18 s) time resolution having wide ranging physical, chemical, material science and biological applications. The quintessential and one of the most fundamental processes in this domain is the generation of phase locked XUV attosecond pulses. The theoretical approach to understand the process incorporates a fully quantum or semi classical or relativistic description of coherent charge dynamics in intense ultrashort electromagnetic fields driving a quantum system (an atom, a molecule, solid band gap materials or surface plasmas). Modelling of such physical and dynamical systems in science and also in many other branches often leads to equations represented in terms of complex multi-dimensional integrals. These integrals can often be solved using the stationary phase approximation, which leads to a series of equations identifying the points in the multi-dimensional space, having most significant contributions in their evaluation. These points are usually indicated as saddle points. The description of the dynamics of quantum mechanical or relativistic systems that results from such an approach enables near to classical physics intuitive perceptions of the processes under investigation. Thus, the saddle point methods are very powerful and valuable general theoretical tools to obtain asymptotic expressions of such solutions and help also to gain physical insights on the underlying phenomena. Such techniques developed in the past have been adapted to study the emission of as pulses by different physical systems and have been widely employed in calculating and estimating the response of matter to intense electromagnetic pulses on ultrafast time scales. Here we provide an extensive disposition of the saddle point approaches unifying their ubiquitous applications within the domain of attoscience valid for simple atomic to more complex condensed matter systems undergoing ultrafast dynamics and present current trends and advancements in the field. In this review we would delineate the methodology, present a synthesis of seminal works and describe the state of the art applications. Finally we also address ultrashort time dynamics of novel materials that have gained much attention recently, namely lower dimensional material systems and micro-plasma systems.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRSDate not supplied

Artemis and Ethics Workshop Lessons Learned

As NASA lays out its Artemis activities, it expects to set precedents in spaceflight for decades to come. Artemis is a far more ambitious program than even Apollo, aimed at developing a sustained human presence on and around the lunar surface, in preparation for Mars exploration. As a result, considering ethical and social concerns in the discussion and design of Artemis is vital to ensuring the future worlds we create are ones where humanity collectively wants to live. By understanding how to reflect on these issues as NASA makes decisions related to Artemis, NASA can avoid unintended consequences stemming from cultural perceptions of human exploration of the solar system that may harm society. We recognize that a diverse range of groups need to be part of this conversation. There are many different views about the work that should happen in space. We recognize that NASA does not hold sole responsibility for determining the ethical path forward in space, as decisions made by commercial, international, and intergovernmental partners play a major role. Inclusive conversations help inform that work. Others have already argued that social scientists and engineers need to work together with inputs from stakeholders to design the future. To begin to answer this need, NASA’s Office of Technology, Policy, and Strategy (OTPS) hosted an Artemis and Ethics Workshop. This workshop was held in Washington, DC from April 12th-14th, 2023 and brought together invited experts in social science fields and NASA managers to discuss ethical, legal, and social aspects (ELSA) of Artemis and human exploration in general. The goal of the workshop was to discuss issues and build connections that NASA managers can consider across variety of ethical issues surrounding Artemis.

Katherine T McBrayer↗
NASA NTRS1993

Sensor fusion for assured vision in space applications

By using emittance and reflectance radiation models, the effects of angle of observation, polarization, and spectral content are analyzed to characterize the geometrical and physical properties--reflectivity, emissivity, orientation, dielectric properties, and roughness--of a sensed surface. Based on this analysis, the use of microwave, infrared, and optical sensing is investigated to assure the perception of surfaces on a typical lunar outpost. Also, the concept of employing several sensors on a lunar outpost is explored. An approach for efficient hardware implementation of the fused sensor systems is discussed.

Collin, Marie-France↗
NASA NTRS2003

Aerodynamics for Revolutionary Air Vehicles

Aeronautics research has seriously declined partly because of the perception that it is a mature science and only incremental improvements are possible. Recent aeronautics roadmapping activities at NASA Langley paint a different picture of the future. Breakthroughs are still felt to be possible if we expand the current design space of today's vehicles and optimize the airspace and vehicles as a system. The paper describes some of the challenges that the aircraft and airline industry face. These challenges include political, technical and environmental issues. Examples of the opportunities and technologies that could provide a different vision for the future are discussed.

Sellers, William L., III↗
NASA NTRS1994

Gravity-regulated formation of the peg in developing cucumber seedlings

It has been proposed that peg formation in the vascular transition region (TR zone) between the hypocotyl and the root in Cucurbitaceae seedlings is a gravimorphogenetic phenomenon. Initiation of the peg became visible 36 h after imbibition when cucumber (Cucumis sativus L. cv. Burpee Hybrid II) seeds were germinated in a horizontal position at 24 degrees C in the dark. Simultaneously, sedimented amyloplasts (putative statoliths) were apparent in the sheath cells surrounding the vascular strands, and in the cortical cells immediately adjacent to them, in the TR zone. In contrast, the other cortical cells, some of which were destined to develop into the peg, contained amyloplasts which were not sedimented. These results suggest that the graviperception mechanism for peg formation may be like that of statoliths in shoot gravitropism. By 48 h following imbibition, the cells of the TR zone still had sedimented amyloplasts but had lost their sensitivity to gravity, possibly because of their maturation.

NASA Program Space Biology↗
NASA NTRS2007

Adaptive Changes in Sensorimotor Coordination and Motion Sickness Following Repeated Exposures to Virtual Environments

Virtual environments offer unique training opportunities, particularly for training astronauts and preadapting them to the novel sensory conditions of microgravity. Two unresolved human factors issues in virtual reality (VR) systems are: 1) potential "cybersickness", and 2) maladaptive sensorimotor performance following exposure to VR systems. Interestingly, these aftereffects are often quite similar to adaptive sensorimotor responses observed in astronauts during and/or following space flight. Initial interpretation of novel sensory information may be inappropriate and result in perceptual errors. Active exploratory behavior in a new environment, with resulting feedback and the formation of new associations between sensory inputs and response outputs, promotes appropriate perception and motor control in the new environment. Thus, people adapt to consistent, sustained alterations of sensory input such as those produced by microgravity, unilateral labyrinthectomy and experimentally produced stimulus rearrangements. The purpose of this research was to compare disturbances in sensorimotor coordination produced by dome and head-mounted virtual environment displays and to examine the effects of exposure duration, and repeated exposures to VR systems. The first study examined disturbances in balance control, and the second study examined disturbances in eye-head-hand (EHH) and eye-head coordination.

Harm, D. L.↗
NASA NTRS2014

Multiagent Flight Control in Dynamic Environments with Cooperative Coevolutionary Algorithms

Dynamic environments in which objectives and environmental features change with respect to time pose a difficult problem with regards to planning optimal paths through these environments. Path planning methods are typically computationally expensive, and are often difficult to implement in real time if system objectives are changed. This computational problem is compounded when multiple agents are present in the system, as the state and action space grows exponentially with the number of agents in the system. In this work, we use cooperative coevolutionary algorithms in order to develop policies which control agent motion in a dynamic multiagent unmanned aerial system environment such that goals and perceptions change, while ensuring safety constraints are not violated. Rather than replanning new paths when the environment changes, we develop a policy which can map the new environmental features to a trajectory for the agent while ensuring safe and reliable operation, while providing 92% of the theoretically optimal performance.

Coevolution↗
NASA NTRS1996

Gravitropism in roots of intermediate-starch mutants of Arabidopsis

Gravitropism was studied in roots of wild type (WT) Arabidopsis thaliana (L.) Heynh. (strain Wassilewskija) and three starch-deficient mutants that were generated by T-DNA insertional mutagenesis. One of these mutants was starchless while the other two were intermediate mutants, which had 51% and 60%, respectively, of the WT amount of starch as determined by light and electron microscopy. The four parameters used to assay gravitropism were: orientation during vertical growth, time course of curvature, induction, and intermittent stimulation experiments. WT roots were much more responsive to gravity than were roots of the starchless mutant, and the intermediate starch mutants exhibited an intermediate graviresponse. Our data suggest that lowered starch content in the mutants primarily affects gravitropism rather than differential growth because both phototropic curvature and growth rates were approximately equal among all four genotypes. Since responses of intermediate-starch mutants were closer to the WT response than to the starchless mutant, it appears that 51-60% of the WT level of starch is near the threshold amount needed for full gravitropic sensitivity. While other interpretations are possible, the data are consistent with the starch statolith hypothesis for gravity perception in that the degree of graviresponsiveness is proportional to the total mass of plastids per cell.

NASA Program Space Biology↗
NASA NTRS2005

Magnetic levitation-based Martian and Lunar gravity simulator

Missions to Mars will subject living specimens to a range of low gravity environments. Deleterious biological effects of prolonged exposure to Martian gravity (0.38 g), Lunar gravity (0.17 g), and microgravity are expected, but the mechanisms involved and potential for remedies are unknown. We are proposing the development of a facility that provides a simulated Martian and Lunar gravity environment for experiments on biological systems in a well controlled laboratory setting. The magnetic adjustable gravity simulator will employ intense, inhomogeneous magnetic fields to exert magnetic body forces on a specimen that oppose the body force of gravity. By adjusting the magnetic field, it is possible to continuously adjust the total body force acting on a specimen. The simulator system considered consists of a superconducting solenoid with a room temperature bore sufficiently large to accommodate small whole organisms, cell cultures, and gravity sensitive bio-molecular solutions. It will have good optical access so that the organisms can be viewed in situ. This facility will be valuable for experimental observations and public demonstrations of systems in simulated reduced gravity. c2005 Published by Elsevier Ltd on behalf of COSPAR.

Non-NASA Center↗