Complex Pupil Masks for Aberrated Imaging of Closely Spaced Objects

NASA Astrophysics Data System (ADS)

Reddy, A. N. K.; Sagar, D. K.; Khonina, S. N.

2017-12-01

Current approach demonstrates the suppression of optical side-lobes and the contraction of the main lobe in the composite image of two object points of the optical system under the influence of defocusing effect when an asymmetric phase edges are imposed over the apodized circular aperture. The resolution of two point sources having different intensity ratio is discussed in terms of the modified Sparrow criterion, functions of the degree of coherence of the illumination, the intensity difference and the degree of asymmetric phase masking. Here we have introduced and explored the effects of focus aberration (defect-of-focus) on the two-point resolution of the optical systems. Results on the aberrated composite image of closely spaced objects with amplitude mask and asymmetric phase masks forms a significant contribution in astronomical and microscopic observations.

Resolution of Closely Spaced Optical Targets Using Maximum Likelihood Estimator and Maximum Entropy Method: A Comparison Study

DTIC Science & Technology

1981-03-03

Government Agencies. The views and conclusions contained in this document are those of the contractor and should not be interpreted as necessarily...resolving closely spaced j optical point targets are compared using Monte Carlo simulation ,esults for three different examples. It is found that the MEM is...although no direct compari- son was given. The objective of this report is to compare the capabilities of MLE and MEM in resolving two optical CSO’s

Space Weather Impacts to Conjunction Assessment: A NASA Robotic Orbital Safety Perspective

NASA Technical Reports Server (NTRS)

Ghrist, Richard; Ghrist, Richard; DeHart, Russel; Newman, Lauri

2013-01-01

National Aeronautics and Space Administration (NASA) recognizes the risk of on-orbit collisions from other satellites and debris objects and has instituted a process to identify and react to close approaches. The charter of the NASA Robotic Conjunction Assessment Risk Analysis (CARA) task is to protect NASA robotic (unmanned) assets from threats posed by other space objects. Monitoring for potential collisions requires formulating close-approach predictions a week or more in the future to determine analyze, and respond to orbital conjunction events of interest. These predictions require propagation of the latest state vector and covariance assuming a predicted atmospheric density and ballistic coefficient. Any differences between the predicted drag used for propagation and the actual drag experienced by the space objects can potentially affect the conjunction event. Therefore, the space environment itself, in particular how space weather impacts atmospheric drag, is an essential element to understand in order effectively to assess the risk of conjunction events. The focus of this research is to develop a better understanding of the impact of space weather on conjunction assessment activities: both accurately determining the current risk and assessing how that risk may change under dynamic space weather conditions. We are engaged in a data-- ]mining exercise to corroborate whether or not observed changes in a conjunction event's dynamics appear consistent with space weather changes and are interested in developing a framework to respond appropriately to uncertainty in predicted space weather. In particular, we use historical conjunction event data products to search for dynamical effects on satellite orbits from changing atmospheric drag. Increased drag is expected to lower the satellite specific energy and will result in the satellite's being 'later' than expected, which can affect satellite conjunctions in a number of ways depending on the two satellites' orbits and the geometry of the conjunction. These satellite time offsets can form the basis of a new technique under development to determine whether space weather perturbations, such as coronal mass ejections, are likely to increase, decrease, or have a neutral effect on the collision risk due to a particular close approach.

Optimization of constellation jettisoning regards to short term collision risks

NASA Astrophysics Data System (ADS)

Handschuh, D.-DA.-A.; Bourgeois, E.

2018-04-01

The space debris problematic is directly linked to the in-orbit collision risk between artificial satellites. With the increase of the space constellation projects, a multiplication of multi-payload launches should occur. In the specific cases where many satellites are injected into orbit with the same launcher upper stage, all these objects will be placed on similar orbits, very close one from each other, at a specific moment where their control capabilities will be very limited. Under this hypothesis, it is up to the launcher operator to ensure that the simultaneous in-orbit injection is safe enough to guarantee the non-collision risk between all the objects under a ballistic hypothesis eventually considering appropriate uncertainties. The purpose of the present study is to find optimized safe separation conditions to limit the in-orbit collision risk following the injection of many objects on very close orbits in a short-delay mission.

Closed cycle electric discharge laser design investigation

NASA Technical Reports Server (NTRS)

Baily, P. K.; Smith, R. C.

1978-01-01

Closed cycle CO2 and CO electric discharge lasers were studied. An analytical investigation assessed scale-up parameters and design features for CO2, closed cycle, continuous wave, unstable resonator, electric discharge lasing systems operating in space and airborne environments. A space based CO system was also examined. The program objectives were the conceptual designs of six CO2 systems and one CO system. Three airborne CO2 designs, with one, five, and ten megawatt outputs, were produced. These designs were based upon five minute run times. Three space based CO2 designs, with the same output levels, were also produced, but based upon one year run times. In addition, a conceptual design for a one megawatt space based CO laser system was also produced. These designs include the flow loop, compressor, and heat exchanger, as well as the laser cavity itself. The designs resulted in a laser loop weight for the space based five megawatt system that is within the space shuttle capacity. For the one megawatt systems, the estimated weight of the entire system including laser loop, solar power generator, and heat radiator is less than the shuttle capacity.

NASA Conjunction Assessment Organizational Approach and the Associated Determination of Screening Volume Sizes

NASA Technical Reports Server (NTRS)

Newman, Lauri K.; Hejduk, Matthew D.

2015-01-01

NASA is committed to safety of flight for all of its operational assets Performed by CARA at NASA GSFC for robotic satellites Focus of this briefing Performed by TOPO at NASA JSC for human spaceflight he Conjunction Assessment Risk Analysis (CARA) was stood up to offer this service to all NASA robotic satellites Currently provides service to 70 operational satellites NASA unmanned operational assets Other USG assets (USGS, USAF, NOAA) International partner assets Conjunction Assessment (CA) is the process of identifying close approaches between two orbiting objects; sometimes called conjunction screening The Joint Space Operations Center (JSpOC) a USAF unit at Vandenberg AFB, maintains the high accuracy catalog of space objects, screens CARA-supported assets against the catalog, performs OD tasking, and generates close approach data.

Proceedings of the Space Surveillance Workshop (11th) Held in Lexington, Massachusetts on 30 March-1 April 1993. Volume 1

DTIC Science & Technology

1993-04-01

are so close together, there is a great deal of mistagged metric data from the SPACETRACK sensors on these objects. The resulting orbital element sets ...including an attempt to combine U.S. Space Command element sets for each Lageos-2 related object in orbit with DSN angle data to determine the actual...Predict error at next observation -Maintain track to minimize reacquistion load -Estimate orbital element sets -Update time for next observation

Dynamic optimization of ISR sensors using a risk-based reward function applied to ground and space surveillance scenarios

NASA Astrophysics Data System (ADS)

DeSena, J. T.; Martin, S. R.; Clarke, J. C.; Dutrow, D. A.; Newman, A. J.

2012-06-01

As the number and diversity of sensing assets available for intelligence, surveillance and reconnaissance (ISR) operations continues to expand, the limited ability of human operators to effectively manage, control and exploit the ISR ensemble is exceeded, leading to reduced operational effectiveness. Automated support both in the processing of voluminous sensor data and sensor asset control can relieve the burden of human operators to support operation of larger ISR ensembles. In dynamic environments it is essential to react quickly to current information to avoid stale, sub-optimal plans. Our approach is to apply the principles of feedback control to ISR operations, "closing the loop" from the sensor collections through automated processing to ISR asset control. Previous work by the authors demonstrated non-myopic multiple platform trajectory control using a receding horizon controller in a closed feedback loop with a multiple hypothesis tracker applied to multi-target search and track simulation scenarios in the ground and space domains. This paper presents extensions in both size and scope of the previous work, demonstrating closed-loop control, involving both platform routing and sensor pointing, of a multisensor, multi-platform ISR ensemble tasked with providing situational awareness and performing search, track and classification of multiple moving ground targets in irregular warfare scenarios. The closed-loop ISR system is fullyrealized using distributed, asynchronous components that communicate over a network. The closed-loop ISR system has been exercised via a networked simulation test bed against a scenario in the Afghanistan theater implemented using high-fidelity terrain and imagery data. In addition, the system has been applied to space surveillance scenarios requiring tracking of space objects where current deliberative, manually intensive processes for managing sensor assets are insufficiently responsive. Simulation experiment results are presented. The algorithm to jointly optimize sensor schedules against search, track, and classify is based on recent work by Papageorgiou and Raykin on risk-based sensor management. It uses a risk-based objective function and attempts to minimize and balance the risks of misclassifying and losing track on an object. It supports the requirement to generate tasking for metric and feature data concurrently and synergistically, and account for both tracking accuracy and object characterization, jointly, in computing reward and cost for optimizing tasking decisions.

Is It Time for Space Debris Reduction Capabilities?

DTIC Science & Technology

2009-04-01

The original document contains color images . 14. ABSTRACT For over 50 years, space-faring nations have launched objects into space, resulting in...have seen an increased risk of collision. Most debris resides in low earth orbit (the satellite freeway where bulk of imaging satellites reside... imaging , radar, etc). The close proximity to the Earth allows for images and photographs to be captured in greater detail than higher orbits

LISA: Astrophysics Out to z Approximately 10 with Low-Frequency Gravitational Waves

NASA Technical Reports Server (NTRS)

Stebbins, Robin T.

2008-01-01

This viewgraph presentation reviews the Laser Interferometer Space Antenna (LISA). LISA os a joint ESA-NASA project to design, build and operate a space-based gravitational wave detector. The 5 million Kilometer long detector will consist of three spacecraft orbiting the Sun in a triangular formation. Space-Time strains induced by gravitational waves are detected by measuring changes in the separation of fiducial masses with laser interferometry. LISA is expected to detect signals from merging massive black holes, compact stellar objects spiraling into super massive black holes in galactic nuclei, thousands of close binaries of compact objects in the Milky way and possible backgrounds of cosmological origin.

Accessible Near-Earth Objects (NEOs)

NASA Technical Reports Server (NTRS)

Barbee, Brent W.

2015-01-01

Near Earth Objects (NEOs) are asteroids and comets whose orbits are in close proximity to Earth's orbit; specifically, they have perihelia less than 1.3 astronomical units. NEOs particularly near Earth asteroids (NEAs) are identified as potential destinations for future human exploration missions. In this presentation I provide an overview of the current state of knowledge regarding the astrodynamical accessibility of NEAs according to NASA's Near Earth Object Human Space Flight Accessible Targets Study (NHATS). I also investigate the extremes of NEA accessibility using case studies and illuminate the fact that a space-based survey for NEOs is essential to expanding the set of known accessible NEAs for future human exploration missions.

Doublet Pulse Coherent Laser Radar for Tracking of Resident Space Objects

NASA Technical Reports Server (NTRS)

Prasad, Narasimha S.; Rudd, Van; Shald, Scott; Sandford, Stephen; Dimarcantonio, Albert

2014-01-01

In this paper, the development of a long range ladar system known as ExoSPEAR at NASA Langley Research Center for tracking rapidly moving resident space objects is discussed. Based on 100 W, nanosecond class, near-IR laser, this ladar system with coherent detection technique is currently being investigated for short dwell time measurements of resident space objects (RSOs) in LEO and beyond for space surveillance applications. This unique ladar architecture is configured using a continuously agile doublet-pulse waveform scheme coupled to a closed-loop tracking and control loop approach to simultaneously achieve mm class range precision and mm/s velocity precision and hence obtain unprecedented track accuracies. Salient features of the design architecture followed by performance modeling and engagement simulations illustrating the dependence of range and velocity precision in LEO orbits on ladar parameters are presented. Estimated limits on detectable optical cross sections of RSOs in LEO orbits are discussed.

Debris Mitigation as a Component of Space Traffic Management

NASA Astrophysics Data System (ADS)

Kemper Force, M.

2012-01-01

The necessity of a traffic management in space is a consequence of our "free use" of it over the past fifty years, during which certain orbits have accumulated a significant amount of debris that may, in the future, threaten the feasibility of their use. This paper encapsulates the primary issues involved in the concept of space traffic management through basic questions, using as a case study the recent alarm caused by two close-misses of the ISS in one week, in order to guide the reader to an understanding of the current need for a space traffic management regime. The paper will describe the fundamental elements of space traffic management, including the tracking of objects, conjunction assessment, collision avoidance and orbital mechanics to understand why Earth-bound systems cannot be extrapolated to space. The paper will then focus on the primary concern of space debris, the acceptance and use of current guidelines in light of the existing corpus juris spatialis and international law, positing that the guidelines may soon develop into a customary norm. The paper will conclude that the latest close calls with the ISS demonstrate we cannot count on the mere vastness of space to reduce the probability of collisions with space objects. Despite the significant political, technical and economic challenges recognized by the International Space University Final Report of 2007, the International Academy of Astronautics' Cosmic Study of 2006 and the IAASS An ICAO for Space?, there is a need for a system to obviate the looming peril before governments and investors will sign on to a comprehensive program which limits their "free" use of space.

Noncontact orientation of objects in three-dimensional space using magnetic levitation

PubMed Central

Subramaniam, Anand Bala; Yang, Dian; Yu, Hai-Dong; Nemiroski, Alex; Tricard, Simon; Ellerbee, Audrey K.; Soh, Siowling; Whitesides, George M.

2014-01-01

This paper describes several noncontact methods of orienting objects in 3D space using Magnetic Levitation (MagLev). The methods use two permanent magnets arranged coaxially with like poles facing and a container containing a paramagnetic liquid in which the objects are suspended. Absent external forcing, objects levitating in the device adopt predictable static orientations; the orientation depends on the shape and distribution of mass within the objects. The orientation of objects of uniform density in the MagLev device shows a sharp geometry-dependent transition: an analytical theory rationalizes this transition and predicts the orientation of objects in the MagLev device. Manipulation of the orientation of the levitating objects in space is achieved in two ways: (i) by rotating and/or translating the MagLev device while the objects are suspended in the paramagnetic solution between the magnets; (ii) by moving a small external magnet close to the levitating objects while keeping the device stationary. Unlike mechanical agitation or robotic selection, orienting using MagLev is possible for objects having a range of different physical characteristics (e.g., different shapes, sizes, and mechanical properties from hard polymers to gels and fluids). MagLev thus has the potential to be useful for sorting and positioning components in 3D space, orienting objects for assembly, constructing noncontact devices, and assembling objects composed of soft materials such as hydrogels, elastomers, and jammed granular media. PMID:25157136

Noncontact orientation of objects in three-dimensional space using magnetic levitation.

PubMed

Subramaniam, Anand Bala; Yang, Dian; Yu, Hai-Dong; Nemiroski, Alex; Tricard, Simon; Ellerbee, Audrey K; Soh, Siowling; Whitesides, George M

2014-09-09

This paper describes several noncontact methods of orienting objects in 3D space using Magnetic Levitation (MagLev). The methods use two permanent magnets arranged coaxially with like poles facing and a container containing a paramagnetic liquid in which the objects are suspended. Absent external forcing, objects levitating in the device adopt predictable static orientations; the orientation depends on the shape and distribution of mass within the objects. The orientation of objects of uniform density in the MagLev device shows a sharp geometry-dependent transition: an analytical theory rationalizes this transition and predicts the orientation of objects in the MagLev device. Manipulation of the orientation of the levitating objects in space is achieved in two ways: (i) by rotating and/or translating the MagLev device while the objects are suspended in the paramagnetic solution between the magnets; (ii) by moving a small external magnet close to the levitating objects while keeping the device stationary. Unlike mechanical agitation or robotic selection, orienting using MagLev is possible for objects having a range of different physical characteristics (e.g., different shapes, sizes, and mechanical properties from hard polymers to gels and fluids). MagLev thus has the potential to be useful for sorting and positioning components in 3D space, orienting objects for assembly, constructing noncontact devices, and assembling objects composed of soft materials such as hydrogels, elastomers, and jammed granular media.

The infrared video image pseudocolor processing system

NASA Astrophysics Data System (ADS)

Zhu, Yong; Zhang, JiangLing

2003-11-01

The infrared video image pseudo-color processing system, emphasizing on the algorithm and its implementation for measured object"s 2D temperature distribution using pseudo-color technology, is introduced in the paper. The data of measured object"s thermal image is the objective presentation of its surface temperature distribution, but the color has a close relationship with people"s subjective cognition. The so-called pseudo-color technology cross the bridge between subjectivity and objectivity, and represents the measured object"s temperature distribution in reason and at first hand. The algorithm of pseudo-color is based on the distance of IHS space. Thereby the definition of pseudo-color visual resolution is put forward. Both the software (which realize the map from the sample data to the color space) and the hardware (which carry out the conversion from the color space to palette by HDL) co-operate. Therefore the two levels map which is logic map and physical map respectively is presented. The system has been used abroad in failure diagnose of electric power devices, fire protection for lifesaving and even SARS detection in CHINA lately.

Understanding the basis of space closure in Orthodontics for a more efficient orthodontic treatment

PubMed Central

Ribeiro, Gerson Luiz Ulema; Jacob, Helder B.

2016-01-01

ABSTRACT Introduction: Space closure is one of the most challenging processes in Orthodontics and requires a solid comprehension of biomechanics in order to avoid undesirable side effects. Understanding the biomechanical basis of space closure better enables clinicians to determine anchorage and treatment options. In spite of the variety of appliance designs, space closure can be performed by means of friction or frictionless mechanics, and each technique has its advantages and disadvantages. Friction mechanics or sliding mechanics is attractive because of its simplicity; the space site is closed by means of elastics or coil springs to provide force, and the brackets slide on the orthodontic archwire. On the other hand, frictionless mechanics uses loop bends to generate force to close the space site, allowing differential moments in the active and reactive units, leading to a less or more anchorage control, depending on the situation. Objective: This article will discuss various theoretical aspects and methods of space closure based on biomechanical concepts. PMID:27275623

Design of an auto change mechanism and intelligent gripper for the space station

NASA Technical Reports Server (NTRS)

Dehoff, Paul H.; Naik, Dipak P.

1989-01-01

Robot gripping of objects in space is inherently demanding and dangerous and nowhere is this more clearly reflected than in the design of the robot gripper. An object which escapes the gripper in a micro g environment is launched not dropped. To prevent this, the gripper must have sensors and signal processing to determine that the object is properly grasped, e.g., grip points and gripping forces and, if not, to provide information to the robot to enable closed loop corrections to be made. The sensors and sensor strategies employed in the NASA/GSFC Split-Rail Parallel Gripper are described. Objectives and requirements are given followed by the design of the sensor suite, sensor fusion techniques and supporting algorithms.

Horsehead Nebula

NASA Image and Video Library

1999-12-01

Rising from a sea of dust and gas like a giant seahorse, the Horsehead nebula is one of the most photographed objects in the sky. NASA Hubble Space Telescope took a close-up look at this heavenly icon, revealing the cloud intricate structure.

Harnessing Orbital Debris to Sense the Space Environment

NASA Astrophysics Data System (ADS)

Mutschler, S.; Axelrad, P.; Matsuo, T.

A key requirement for accurate space situational awareness (SSA) is knowledge of the non-conservative forces that act on space objects. These effects vary temporally and spatially, driven by the dynamical behavior of space weather. Existing SSA algorithms adjust space weather models based on observations of calibration satellites. However, lack of sufficient data and mismodeling of non-conservative forces cause inaccuracies in space object motion prediction. The uncontrolled nature of debris makes it particularly sensitive to the variations in space weather. Our research takes advantage of this behavior by inverting observations of debris objects to infer the space environment parameters causing their motion. In addition, this research will produce more accurate predictions of the motion of debris objects. The hypothesis of this research is that it is possible to utilize a "cluster" of debris objects, objects within relatively close proximity of each other, to sense their local environment. We focus on deriving parameters of an atmospheric density model to more precisely predict the drag force on LEO objects. An Ensemble Kalman Filter (EnKF) is used for assimilation; the prior ensemble to the posterior ensemble is transformed during the measurement update in a manner that does not require inversion of large matrices. A prior ensemble is utilized to empirically determine the nonlinear relationship between measurements and density parameters. The filter estimates an extended state that includes position and velocity of the debris object, and atmospheric density parameters. The density is parameterized as a grid of values, distributed by latitude and local sidereal time over a spherical shell encompassing Earth. This research focuses on LEO object motion, but it can also be extended to additional orbital regimes for observation and refinement of magnetic field and solar radiation models. An observability analysis of the proposed approach is presented in terms of the measurement cadence necessary to estimate the local space environment.

Evaluating Nextgen Closely Spaced Parallel Operations Concepts with Validated Human Performance Models: Flight Deck Guidelines

NASA Technical Reports Server (NTRS)

Hooey, Becky Lee; Gore, Brian Francis; Mahlstedt, Eric; Foyle, David C.

2013-01-01

The objectives of the current research were to develop valid human performance models (HPMs) of approach and land operations; use these models to evaluate the impact of NextGen Closely Spaced Parallel Operations (CSPO) on pilot performance; and draw conclusions regarding flight deck display design and pilot-ATC roles and responsibilities for NextGen CSPO concepts. This document presents guidelines and implications for flight deck display designs and candidate roles and responsibilities. A companion document (Gore, Hooey, Mahlstedt, & Foyle, 2013) provides complete scenario descriptions and results including predictions of pilot workload, visual attention and time to detect off-nominal events.

Multiple-Sensor Discrimination of Closely-Spaced Objects on a Ballistic Trajectory

DTIC Science & Technology

2015-05-18

Nominal System Architecture ..................................................................................... 8 2 Simulation Environment... architecture ........................................................................................... 8 Figure 2. Simulation environment developed...uncertainty band for one or multiple sensors within the observation architecture . Resolving targets from one sensor image to another can prove difficult

Geosynthetic wall performance : facing pressure and deformation : final report.

DOT National Transportation Integrated Search

2017-02-01

The objective of the study was to validate the performance of blocked-faced Geosynthetic Reinforced Soil (GRS) wall and to validate the Colorado Department of Transportations (CDOT) decision to waive the positive block connection for closely-space...

Literacy Networks: Following the Circulation of Texts, Bodies, and Objects in the Schooling and Online Gaming of One Youth

ERIC Educational Resources Information Center

Leander, Kevin M.; Lovvorn, Jason F.

2006-01-01

In this article, we offer an approach to conceiving of the relation between literacy practices and space-time. Literacy, embedded in other forms of activity, has a unique role in producing and organizing space-time relations, and such relations provide for different forms of cognition and learning. Closely examining how literacy practices produce…

STS-37 The Payload bay door closing at PCR Pad B

NASA Technical Reports Server (NTRS)

1991-01-01

The primary objective of the STS-37 mission was to deploy the Gamma Ray Observatory. The mission was launched at 9:22:44 am on April 5, 1991, onboard the space shuttle Atlantis. This videotape shows the payload bay doors being closed. Included are views of the Gamma Ray Observatory in the payload bay, and the clean room operations in the Payload Changeout Room (PCR).

Improved Space Surveillance Network (SSN) Scheduling using Artificial Intelligence Techniques

NASA Astrophysics Data System (ADS)

Stottler, D.

There are close to 20,000 cataloged manmade objects in space, the large majority of which are not active, functioning satellites. These are tracked by phased array and mechanical radars and ground and space-based optical telescopes, collectively known as the Space Surveillance Network (SSN). A better SSN schedule of observations could, using exactly the same legacy sensor resources, improve space catalog accuracy through more complementary tracking, provide better responsiveness to real-time changes, better track small debris in low earth orbit (LEO) through efficient use of applicable sensors, efficiently track deep space (DS) frequent revisit objects, handle increased numbers of objects and new types of sensors, and take advantage of future improved communication and control to globally optimize the SSN schedule. We have developed a scheduling algorithm that takes as input the space catalog and the associated covariance matrices and produces a globally optimized schedule for each sensor site as to what objects to observe and when. This algorithm is able to schedule more observations with the same sensor resources and have those observations be more complementary, in terms of the precision with which each orbit metric is known, to produce a satellite observation schedule that, when executed, minimizes the covariances across the entire space object catalog. If used operationally, the results would be significantly increased accuracy of the space catalog with fewer lost objects with the same set of sensor resources. This approach inherently can also trade-off fewer high priority tasks against more lower-priority tasks, when there is benefit in doing so. Currently the project has completed a prototyping and feasibility study, using open source data on the SSN's sensors, that showed significant reduction in orbit metric covariances. The algorithm techniques and results will be discussed along with future directions for the research.

Closeup oblique view of the forward and starboard sides of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Close-up oblique view of the forward and starboard sides of the Orbiter Discovery in the Vehicle Assembly Building at NASA's Kennedy Space Center. The view shows the void created by the removal of the Forward Reaction Control System Module. The void has a clear flexible covering to maintain positive pressure in the void to minimize foreign object contamination possibilities in the orbiter. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

Closeup view of the forward and starboard sides of the ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Close-up view of the forward and starboard sides of the Orbiter Discovery in the Vehicle Assembly Building at NASA's Kennedy Space Center. The view shows the void created by the removal of the Forward Reaction Control System Module. The void has a clear flexible covering to maintain positive pressure in the void to minimize foreign object contamination possibilities in the orbiter. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

A review of cooperative and uncooperative spacecraft pose determination techniques for close-proximity operations

NASA Astrophysics Data System (ADS)

Opromolla, Roberto; Fasano, Giancarmine; Rufino, Giancarlo; Grassi, Michele

2017-08-01

The capability of an active spacecraft to accurately estimate its relative position and attitude (pose) with respect to an active/inactive, artificial/natural space object (target) orbiting in close-proximity is required to carry out various activities like formation flying, on-orbit servicing, active debris removal, and space exploration. According to the specific mission scenario, the pose determination task involves both theoretical and technological challenges related to the search for the most suitable algorithmic solution and sensor architecture, respectively. As regards the latter aspect, electro-optical sensors represent the best option as their use is compatible with mass and power limitation of micro and small satellites, and their measurements can be processed to estimate all the pose parameters. Overall, the degree of complexity of the challenges related to pose determination largely varies depending on the nature of the targets, which may be actively/passively cooperative, uncooperative but known, or uncooperative and unknown space objects. In this respect, while cooperative pose determination has been successfully demonstrated in orbit, the uncooperative case is still under study by universities, research centers, space agencies and private companies. However, in both the cases, the demand for space applications involving relative navigation maneuvers, also in close-proximity, for which pose determination capabilities are mandatory, is significantly increasing. In this framework, a review of state-of-the-art techniques and algorithms developed in the last decades for cooperative and uncooperative pose determination by processing data provided by electro-optical sensors is herein presented. Specifically, their main advantages and drawbacks in terms of achieved performance, computational complexity, and sensitivity to variability of pose and target geometry, are highlighted.

Sample levitation and melt in microgravity

NASA Technical Reports Server (NTRS)

Moynihan, Philip I. (Inventor)

1990-01-01

A system is described for maintaining a sample material in a molten state and away from the walls of a container in a microgravity environment, as in a space vehicle. A plurality of sources of electromagnetic radiation, such as an infrared wavelength, are spaced about the object, with the total net electromagnetic radiation applied to the object being sufficient to maintain it in a molten state, and with the vector sum of the applied radiation being in a direction to maintain the sample close to a predetermined location away from the walls of a container surrounding the sample. For a processing system in a space vehicle that orbits the Earth, the net radiation vector is opposite the velocity of the orbiting vehicle.

Sample levitation and melt in microgravity

NASA Technical Reports Server (NTRS)

Moynihan, Philip I. (Inventor)

1987-01-01

A system is described for maintaining a sample material in a molten state and away from the walls of a container in a microgravity environment, as in a space vehicle. A plurality of sources of electromagnetic radiation, such as of an infrared wavelength, are spaced about the object, with the total net electromagnetic radiation applied to the object being sufficient to maintain it in a molten state, and with the vector sum of the applied radiation being in a direction to maintain the sample close to a predetermined location away from the walls of a container surrounding the sample. For a processing system in a space vehicle that orbits the Earth, the net radiation vector is opposite the velocity of the orbiting vehicle.

Achievements and Future Plan of Interplanetary CubeSats and Micro-Sats in Japan

NASA Astrophysics Data System (ADS)

Funase, Ryu

2016-07-01

This paper introduces Japanese achievements and future plans of CubeSats and Micro-Sats for deep space exploration. As the first step toward deep space mission by such tiny spacecraft, University of Tokyo and Japan Aerospace Exploration Agency (JAXA) developed the world's first deep space micro-spacecraft PROCYON (Proximate Object Close flYby with Optical Navigation). Its mission objective is to demonstrate a micro-spacecraft bus technology for deep space exploration and proximity flyby to asteroids performing optical measurements. PROCYON was launched into the Earth departure trajectory on December 3, 2014 together with Japanese asteroid sample return mission Hayabusa-2. PROCYON successfully completed the bus system demonstration mission in its interplanetary flight. Currently, Japan is not only pursuing the improvement and utilization of the demonstrated micro-sat deep space bus system with a weight of tens of kg or more for more practical scientific deep space missions, but also trying to develop smaller spacecraft with a weight of less than tens of kg, namely CubeSats, for deep space exploration. We are proposing a self-contained 6U CubeSat mission for the rideshare opportunity on the USA's SLS EM-1 mission, which will fly to a libration orbit around Earth-Moon L2 point and perform scientific observations of the Earth and the Moon. We are also seeking the possibility of CubeSats which is carried by a larger spacecraft to the destination and supports the mission by taking advantage of its low-cost and risk-tolerable feature. As an example of such style of CubeSat missions, we are studying a CubeSat for close observations of an asteroid, which will be carried to the target asteroid by a larger mother spacecraft. This CubeSat is released from the mother spacecraft to make a close flyby for scientific observations, which is difficult to be performed by the mother spacecraft if we consider the risk of the collision to the target asteroid or dust particles ejected from the asteroid. In order to utilize the large deep space maneuverability of the mother spacecraft, the CubeSat is retrieved by the mother spacecraft after the close flyby observation and it is carried to the next target asteroid to realize multiple asteroids flyby exploration.

Gap Analysis: Rethinking the Conceptual Foundations

DTIC Science & Technology

2008-04-23

there could exist a basis for gap in capability and, therefore, a desire to close the capability gap . What one desires versus what one has is, in...Analysis is not intended to close the space between the most distant extremes or the rarest occurrences. Rather, Gap Analysis is centered on the larger...åÖÉ=======- 13 - = = Research Objectives The process of identifying needs and unsatisfied desires, or gaps in capability—in essence, the goal—is

Growth in the Number of SSN Tracked Orbital Objects

NASA Technical Reports Server (NTRS)

Stansbery, Eugene G.

2004-01-01

The number of objects in earth orbit tracked by the US Space Surveillance Network (SSN) has experienced unprecedented growth since March, 2003. Approximately 2000 orbiting objects have been added to the "Analyst list" of tracked objects. This growth is primarily due to the resumption of full power/full time operation of the AN/FPS-108 Cobra Dane radar located on Shemya Island, AK. Cobra Dane is an L-band (23-cm wavelength) phased array radar which first became operational in 1977. Cobra Dane was a "Collateral Sensor" in the SSN until 1994 when its communication link with the Space Control Center (SCC) was closed. NASA and the Air Force conducted tests in 1999 using Cobra Dane to detect and track small debris. These tests confirmed that the radar was capable of detecting and maintaining orbits on objects as small as 5-cm diameter. Subsequently, Cobra Dane was reconnected to the SSN and resumed full power/full time space surveillance operations on March 4, 2003. This paper will examine the new data and its implications to the understanding of the orbital debris environment and orbital safety.

Concept of a space optoelectronic system for environmental monitoring of the near-earth space, atmosphere, and earth surface

NASA Astrophysics Data System (ADS)

Eltsov, Anatoli V.; Karasev, Vladimir I.; Kolotkov, Vjacheslav V.; Kondranin, Timothy V.

1997-06-01

The sharp increase of the man-induced pressure on the environment and hence the need to predict and monitor natural anomalies makes global monitoring of the ecosphere of planet Earth an issue of vital importance. The notion of the ecosphere covers three basic shells closely interacting with each other: the near-Earth space, the atmosphere and the Earth surface. In the near-Earth space (covering 100 to 2000 km altitudes) the primary objects of monitoring are: functioning artificial space objects, the fragments of their constructions or space rubbish (which by estimation amounts to 3.5 million pieces including 30,000 to 70,000 objects having dimensions sufficient for heavy damaging or even destroying functioning space objects) and objects of space origin (asteroids, meteorites and comets) whose trajectories come closely enough to the Earth. Maximum concentrations of space rubbish observed on orbits with altitudes of 800, 1000 and 1500 km and inclinations of 60 to 100 deg. are related in the first place to spacecraft launch requirements. Taking into account the number of launches implemented by different countries in the framework of their own space programs the probability of collision of functioning spacecraft with space rubbish may be estimation increase from (1.5 - 3.5)% at present to (15 - 40)% by 2020. Besides, registration of space radiation flow intensity and the solar activity is no less important in this space area. Subject to control in the atmosphere are time and space variations in temperature fields, humidity, tracing gas concentrations, first of all ozone and greenhouse gases, the state of the cloud cover, wind velocity, etc. The range of objects to be under environmental management of Earth surface is just as diverse and essentially should include the state of the surface and the near-surface layer of seas and oceans, internal reservoirs, the cryosphere and the land surface along with vegetation cover, natural resources and human activities. No matter how large the space (from several meters to hundreds of kilometers) and time (from an hour to several months) scales of the above monitoring might be there is a common dominating factor which could favor creation of a general- purpose observation and control system based on passive optoelectronic instrumentation of different levels of sophistication. This dominating factor refers to the possibility of obtaining information about the state of objects by way to recording parameters of radiation emitted by them in wavelengths of 250 nm to tens of microns. The fact that phenomena and processes occurring in the atmosphere are closely interrelated gives implications as to the structure of such a system which is supposed to be a common information network basically consisting of an orbiting constellation of a number of small-size spacecraft equipped with optoelectronic instrumentation of different complexity, and a ground segment to provide acquisition and processing of information about the status of every ecosphere shell including comprehensive thematic analysis. The existing domestic (based on the `Meteor', `Resurs-O', `Okean', etc. spacecraft) and foreign (NOAA, SPOT, LANDSAT, ERS, etc.) space systems are designed for solution of only a limited number of atmosphere monitoring issues, namely those related to meteorology and studies of natural resources. As for the near-Earth space there are at present only ground facilities whose monitoring capabilities are also limited. It should be noted that in recent years in the USA similar activities have been in full swing targeted at creation of a system like the one mentioned above (the Earth Observation System). A system comprising four spacecraft of the NOAA series and a distributed ground network for receiving analog (with 4 km spatial resolution) and digital (with 1 km spatial resolution) multispectral data pertaining to the status of the atmosphere and the underlying surface is currently operational. This system presents some unique features which make it in several applications superior to existing counterparts. The issue of creation and use of similar systems is complex and costly and it can be solved under today's Russian circumstances only at government level by joint efforts of multiple scientific and production organizations. One advantageous approach consists in building the above-mentioned systems using space complexes which have been already developed or are under development.

Phase III Integrated Water Recovery Testing at MSFC - Closed hygiene and potable loop test results and lesson learned

NASA Technical Reports Server (NTRS)

Holder, Donald W., Jr.; Bagdigian, Robert M.

1992-01-01

A series of tests has been conducted at the NASA Marshall Space Flight Center (MSFC) to evaluate the performance of a Space Station Freedom (SSF) pre-development water recovery system. Potable, hygiene, and urine reclamation subsystems were integrated with end-use equipment items and successfully operated for a total of 35 days, including 23 days in closed-loop mode with man-in-the-loop. Although several significant subsystem physical anomalies were encountered, reclaimed potable and hygiene water routinely met current SSF water quality specifications. This paper summarizes the test objectives, system design, test activities/protocols, significant results/anomalies, and major lessons learned.

An analysis of the 2016 Hitomi breakup event

NASA Astrophysics Data System (ADS)

Flegel, Sven; Bennett, James; Lachut, Michael; Möckel, Marek; Smith, Craig

2017-04-01

The breakup of Hitomi (ASTRO-H) on 26 March 2016 is analysed. Debris from the fragmentation is used to estimate the time of the event by propagating backwards and estimating the close approach with the parent object. Based on this method, the breakup event is predicted to have occurred at approximately 01:42 UTC on 26 March 2016. The Gaussian variation of parameters equations based on the instantaneous orbits at the predicted time of the event are solved to gain additional insight into the on-orbit position of Hitomi at the time of the event and to test an alternate approach of determining the event epoch and location. A conjunction analysis is carried out between Hitomi and all catalogued objects which were in orbit around the estimated time of the anomaly. Several debris objects have close approaches with Hitomi; however, there is no evidence to support the breakup was caused by a catalogued object. Debris from both of the largest fragmentation events—the Iridium 33-Cosmos 2251 conjunction in 2009 and the intentional destruction of Fengyun 1C in 2007—is involved in close approaches with Hitomi indicating the persistent threat these events have caused in subsequent space missions. To quantify the magnitude of a potential conjunction, the fragmentation resulting from a collision with the debris is modelled using the EVOLVE-4 breakup model. The debris characteristics are estimated from two-line element data. This analysis is indicative of the threat to space assets that mission planners face due to the growing debris population. The impact of the actual event to the environment is investigated based on the debris associated with Hitomi which is currently contained in the United States Strategic Command's catalogue. A look at the active missions in the orbital vicinity of Hitomi reveals that the Hubble Space Telescope is among the spacecraft which may be immediately affected by the new debris.[Figure not available: see fulltext.

Space Processing Applications Rocket project, SPAR 1

NASA Technical Reports Server (NTRS)

Reeves, F. (Compiler); Chassay, R. (Compiler)

1976-01-01

The experiment objectives, design/operational concepts, and final results of each of nine scientific experiments conducted during the first Space Processing Applications Rocket (SPAR) flight are summarized. The nine individual SPAR experiments, covering a wide and varied range of scientific materials processing objectives, were entitled: solidification of Pb-Sb eutectic, feasibility of producing closed-cell metal foams, characterization of rocket vibration environment by measurement of mixing of two liquids, uniform dispersions of crystallization processing, direct observation of solidification as a function of gravity levels, casting thoria dispersion-strengthened interfaces, contained polycrystalline solidification, and preparation of a special alloy for manufacturing of magnetic hard superconductor under zero-g environment.

Closely-Spaced Objects and Mathematical Groups Combined With a Robust Observational Method

DTIC Science & Technology

2009-09-01

AUTHOR( S ) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) Air Force Research Laboratory...Space Vehicles Directorate,Kirtland AFB,NM,87117 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME( S ) AND ADDRESS(ES...10. SPONSOR/MONITOR’S ACRONYM( S ) 11. SPONSOR/MONITOR’S REPORT NUMBER( S ) 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release

KENNEDY SPACE CENTER, FLA. - The Payload is seen inside of the Bay just before the doors are closed for flight at Pad 39A, Kennedy Space Center, Fla. Discovery, the orbiter for STS-82 mission, is ready for the launch of the second Hubble Space Telescope service mission. The payload consists of the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) that will be installed, Fine Guidance Sensor #1 (FGS-1), and the Space Telescope Imaging Spectrograph (STIS) to be installed. The STS-82 will launch with a crew of seven at 3:54 a.m. EST, Feb. 11, 1997. The launch window is 65 minutes in duration. The Mission Commander for STS-82 is Ken Bowersox. The purpose of the mission is to upgrade the scientific capabilities, service or replace aging components on the Telescope, and provide a reboost to the optimum altitude.

NASA Image and Video Library

1997-02-07

KENNEDY SPACE CENTER, FLA. - The Payload is seen inside of the Bay just before the doors are closed for flight at Pad 39A, Kennedy Space Center, Fla. Discovery, the orbiter for STS-82 mission, is ready for the launch of the second Hubble Space Telescope service mission. The payload consists of the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) that will be installed, Fine Guidance Sensor #1 (FGS-1), and the Space Telescope Imaging Spectrograph (STIS) to be installed. The STS-82 will launch with a crew of seven at 3:54 a.m. EST, Feb. 11, 1997. The launch window is 65 minutes in duration. The Mission Commander for STS-82 is Ken Bowersox. The purpose of the mission is to upgrade the scientific capabilities, service or replace aging components on the Telescope, and provide a reboost to the optimum altitude.

Space Life Sciences Research and Education Program

NASA Technical Reports Server (NTRS)

Coats, Alfred C.

2001-01-01

Since 1969, the Universities Space Research Association (USRA), a private, nonprofit corporation, has worked closely with the National Aeronautics and Space Administration (NASA) to advance space science and technology and to promote education in those areas. USRA's Division of Space Life Sciences (DSLS) has been NASA's life sciences research partner for the past 18 years. For the last six years, our Cooperative Agreement NCC9-41 for the 'Space Life Sciences Research and Education Program' has stimulated and assisted life sciences research and education at NASA's Johnson Space Center (JSC) - both at the Center and in collaboration with outside academic institutions. To accomplish our objectives, the DSLS has facilitated extramural research, developed and managed educational programs, recruited and employed visiting and staff scientists, and managed scientific meetings.

Migration of comets to near-Earth space

NASA Astrophysics Data System (ADS)

Ipatov, S. I.

The orbital evolution of more than 21000 Jupiter-crossing objects under the gravitational influence of planets was investigated. For orbits close to that of Comet 2P, the mean collision probabilities of Jupiter-crossing objects with the terrestrial planets were greater by two orders of magnitude than for some other comets. For initial orbital elements close to those of Comets 2P, 10P, 44P, and 113P, a few objects (<0.1%) got Earth-crossing orbits with semi-major axes a<2 AU and aphelion distances Q<4.2 AU and moved in such orbits for more than 1 Myr (up to tens or even hundreds of Myrs). Some of them even got inner-Earth orbits (Q<0.983 AU) and Aten orbits for millions of years. Most former trans-Neptunian objects that have typical near-Earth object orbits moved in such orbits for millions of years, so during most of this time they were extinct comets or disintegrated into mini-comets.

Multi-axis transient vibration testing of space objects: Test philosophy, test facility, and control strategy

NASA Technical Reports Server (NTRS)

Lachenmayr, Georg

1992-01-01

IABG has been using various servohydraulic test facilities for many years for the reproduction of service loads and environmental loads on all kinds of test objects. For more than 15 years, a multi-axis vibration test facility has been under service, originally designed for earthquake simulation but being upgraded to the demands of space testing. First tests with the DFS/STM showed good reproduction accuracy and demonstrated the feasibility of transient vibration testing of space objects on a multi-axis hydraulic shaker. An approach to structural qualification is possible by using this test philosophy. It will be outlined and its obvious advantages over the state-of-the-art single-axis test will be demonstrated by example results. The new test technique has some special requirements to the test facility exceeding those of earthquake testing. Most important is the high reproduction accuracy demanded for a sophisticated control system. The state-of-the-art approach of analog closed-loop control circuits for each actuator combined with a static decoupling network and an off-line iterative waveform control is not able to meet all the demands. Therefore, the future over-all control system is implemented as hierarchical full digital closed-loop system on a highly parallel transputer network. The innermost layer is the digital actuator controller, the second one is the MDOF-control of the table movement. The outermost layer would be the off-line iterative waveform control, which is dedicated only to deal with the interaction of test table and test object or non-linear effects. The outline of the system will be presented.

Computational algorithms dealing with the classical and statistical mechanics of celestial scale polymers in space elevator technology

NASA Astrophysics Data System (ADS)

Knudsen, Steven; Golubovic, Leonardo

Prospects to build Space Elevator (SE) systems have become realistic with ultra-strong materials such as carbon nano-tubes and diamond nano-threads. At cosmic length-scales, space elevators can be modeled as polymer like floppy strings of tethered mass beads. A new venue in SE science has emerged with the introduction of the Rotating Space Elevator (RSE) concept supported by novel algorithms discussed in this presentation. An RSE is a loopy string reaching into outer space. Unlike the classical geostationary SE concepts of Tsiolkovsky, Artsutanov, and Pearson, our RSE exhibits an internal rotation. Thanks to this, objects sliding along the RSE loop spontaneously oscillate between two turning points, one of which is close to the Earth whereas the other one is in outer space. The RSE concept thus solves a major problem in SE technology which is how to supply energy to the climbers moving along space elevator strings. The investigation of the classical and statistical mechanics of a floppy string interacting with objects sliding along it required development of subtle computational algorithms described in this presentation

Ground Testing of a 10 K Sorption Cryocooler Flight Experiment (BETSCE)

NASA Technical Reports Server (NTRS)

Bard, S.; Wu, J.; Karlmann, P.; Cowgill, P.; Mirate, C.; Rodriguez, J.

1994-01-01

The Brilliant Eyes Ten-Kelvin Sorption Cryocooler Experiment (BETSCE) is a Space Shuttle side-wall-mounted flight experiment designed to demonstrate 10 K sorption cryocooler technology in a space environment. The BETSCE objectives are to: (1) provide a thorough end-to-end characterization and space performance validation of a complete, multistage, automated, closed-cycle hydride sorption cryocooler in the 10 to 30 K temperature range, (2) acquire the quantitative microgravity database required to provide confident engineering design, scaling, and optimization, (3) advance the enabling technologies and resolve integration issues, and (4) provide hardware qualification and safety verification heritage. BETSCE ground tests were the first-ever demonstration of a complete closed-cycle 10 K sorption cryocooler. Test results exceeded functional requirements. This paper summarizes functional and environmental ground test results, planned characterization tests, important development challenges that were overcome, and valuable lessons-learned.

Macroinformational analysis of conditions for controllability of space-vehicle orbit

NASA Astrophysics Data System (ADS)

Glazov, B. I.

2011-12-01

The general axiomatics of information measures for the macro analysis of relations of an information-cybernetic system in the control is introduced. The general structure of a semantically marked graph of open and closed relations of an information-cybernetic system between the participants in the environment, as well as thenecessary axiomatic and technological information-cybernetic system conditions of controllability and observability of objects, for the case of a space vehicle in orbit, are justified.

Geosynchronous Patrol Orbit for Space Situational Awareness

NASA Astrophysics Data System (ADS)

Thompson, B.; Kelecy, T.; Kubancik, T.; Flora, T.; Chylla, M.; Rose, D.

Applying eccentricity to a geosynchronous orbit produces both longitudinal and radial motion when viewed in Earth-fixed coordinates. An interesting family of orbits emerges, useful for “neighborhood patrol” space situational awareness and other missions. The basic result is a periodic (daily), quasielliptical, closed path around a fixed region of the geosynchronous (geo) orbit belt, keeping a sensor spacecraft in relatively close vicinity to designated geo objects. The motion is similar, in some regards, to the relative motion that may be encountered during spacecraft proximity operations, but on a much larger scale. The patrol orbit does not occupy a fixed slot in the geo belt, and the east-west motion can be combined with north-south motion caused by orbital inclination, leading to even greater versatility. Some practical uses of the geo patrol orbit include space surveillance (including catalog maintenance), and general space situational awareness. The patrol orbit offers improved, diverse observation geometry for angles-only sensors, resulting in faster, more accurate orbit determination compared to simple inclined geo orbits. In this paper, we analyze the requirements for putting a spacecraft in a patrol orbit, the unique station keeping requirements to compensate for perturbations, repositioning the patrol orbit to a different location along the geo belt, maneuvering into, around, and out of the volume for proximity operations with objects within the volume, and safe end-of-life disposal requirements.

The Lambda Point Experiment in Microgravity

NASA Technical Reports Server (NTRS)

Lipa, J. A.; Swanson, D. R.; Nissen, J. A.; Chui, T. C. P.

1993-01-01

In October 1992 a low temperature experiment was flown on the Space Shuttle in low earth orbit, using the JPL low temperature research facility. The objective of the mission was to measure the heat capacity and thermal relaxation of helium very close to the lambda point with the smearing effect of gravity removed.

Simultaneous Processing of Visible and Long-Wave Infrared Satellite Imagery

DTIC Science & Technology

2015-10-19

Telescope, formerly the Gamma-ray Large Area Telescope (GLAST), and the Hubble Space Telescope (HST). The visible data was processed with a multi-frame...prevalent in the Hubble pass where the panels were already close to the background values. These results are promising; the dimmer features of the object

NASA Medical Response to Human Spacecraft Accidents

NASA Technical Reports Server (NTRS)

Patlach, Robert

2010-01-01

Manned space flight is risky business. Accidents have occurred and may occur in the future. NASA's manned space flight programs, with all their successes, have had three fatal accidents, one at the launch pad and two in flight. The Apollo fire and the Challenger and Columbia accidents resulted in a loss of seventeen crewmembers. Russia's manned space flight programs have had three fatal accidents, one ground-based and two in flight. These accidents resulted in the loss of five crewmembers. Additionally, manned spacecraft have encountered numerous close calls with potential for disaster. The NASA Johnson Space Center Flight Safety Office has documented more than 70 spacecraft incidents, many of which could have become serious accidents. At the Johnson Space Center (JSC), medical contingency personnel are assigned to a Mishap Investigation Team. The team deploys to the accident site to gather and preserve evidence for the Accident Investigation Board. The JSC Medical Operations Branch has developed a flight surgeon accident response training class to capture the lessons learned from the Columbia accident. This presentation will address the NASA Mishap Investigation Team's medical objectives, planned response, and potential issues that could arise subsequent to a manned spacecraft accident. Educational Objectives are to understand the medical objectives and issues confronting the Mishap Investigation Team medical personnel subsequent to a human space flight accident.

Frictionless segmented mechanics for controlled space closure

PubMed Central

Andrade, Ildeu

2017-01-01

ABSTRACT Extraction spaces may be needed to achieve specific orthodontic goals of positioning the dentition in harmony with the craniofacial complex. However, the fundamental reality that determines the occlusion final position is the control exerted by the orthodontist while closing the extraction spaces. A specific treatment objective may require the posterior teeth to remain in a constant position anteroposteriorly as well as vertically, while the anterior teeth occupy the entire extraction site. Another treatment objective may require the opposite, or any number of intentional alternatives of extraction site closure. The present case report describes a simple controlled segmented mechanic system that permitted definable and predictable force systems to be applied and allowed to predict the treatment outcome with confidence. This case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO) in partial fulfillment of the requirements for Diplomate certification. PMID:28444016

Vision sensing techniques in aeronautics and astronautics

NASA Technical Reports Server (NTRS)

Hall, E. L.

1988-01-01

The close relationship between sensing and other tasks in orbital space, and the integral role of vision sensing in practical aerospace applications, are illustrated. Typical space mission-vision tasks encompass the docking of space vehicles, the detection of unexpected objects, the diagnosis of spacecraft damage, and the inspection of critical spacecraft components. Attention is presently given to image functions, the 'windowing' of a view, the number of cameras required for inspection tasks, the choice of incoherent or coherent (laser) illumination, three-dimensional-to-two-dimensional model-matching, edge- and region-segmentation techniques, and motion analysis for tracking.

NASA's Planetary Defense Coordination Office at NASA HQ

NASA Astrophysics Data System (ADS)

Daou, D.; Johnson, L.; Fast, K. E.; Landis, R.; Friedensen, V. P.; Kelley, M.

2017-12-01

NASA and its partners maintain a watch for near-Earth objects (NEOs), asteroids and comets that pass close to the Earth, as part of an ongoing effort to discover, catalog, and characterize these bodies. The PDCO is responsible for: Ensuring the early detection of potentially hazardous objects (PHOs) - asteroids and comets whose orbit are predicted to bring them within 0.05 Astronomical Units of Earth; and of a size large enough to reach Earth's surface - that is, greater than perhaps 30 to 50 meters; Tracking and characterizing PHOs and issuing warnings about potential impacts; Providing timely and accurate communications about PHOs; and Performing as a lead coordination node in U.S. Government planning for response to an actual impact threat. The PDCO collaborates with other U.S. Government agencies, other national and international agencies, and professional and amateur astronomers around the world. The PDCO also is responsible for facilitating communications between the science community and the public should any potentially hazardous NEO be discovered. In addition, the PDCO works closely with the United Nations Office of Outer Space Affairs, its Committee on the Peaceful Uses of Outer Space, and its Action Team on Near Earth Objects (also known as Action Team 14). The PDCO is a leading member of the International Asteroid Warning Network (IAWN) and the Space Missions Planning Advisory Group (SMPAG), multinational endeavors recommended by the United Nations for an international response to the NEO impact hazard and established and operated by the space-capable nations. The PDCO also communicates with the scientific community through channels such as NASA's Small Bodies Assessment Group (SBAG). In this talk, we will provide an update to the office's various efforts and new opportunities for partnerships in the continuous international effort for Planetary Defense.

Space Processing Applications Rocket project, SPAR 2

NASA Technical Reports Server (NTRS)

1977-01-01

Experiment objectives, design/operational concepts, and final results are summarized for six materials science experiments conducted during the second space processing applications rocket mission flown by NASA. The individual experiments discussed are: (1) solidification of Pb-Sb eutectic; (2) feasibility of producing closed-cell metal foams; (3) direct observation of dendrite remelting and macrosegregation in castings; (4) agglomeration in immiscible liquids; (5) casting dispersion - strengthened composites at zero gravity; and (6) solidification behavior of Al-In alloys under zero gravity conditions.

A deterministic compressive sensing model for bat biosonar.

PubMed

Hague, David A; Buck, John R; Bilik, Igal

2012-12-01

The big brown bat (Eptesicus fuscus) uses frequency modulated (FM) echolocation calls to accurately estimate range and resolve closely spaced objects in clutter and noise. They resolve glints spaced down to 2 μs in time delay which surpasses what traditional signal processing techniques can achieve using the same echolocation call. The Matched Filter (MF) attains 10-12 μs resolution while the Inverse Filter (IF) achieves higher resolution at the cost of significantly degraded detection performance. Recent work by Fontaine and Peremans [J. Acoustic. Soc. Am. 125, 3052-3059 (2009)] demonstrated that a sparse representation of bat echolocation calls coupled with a decimating sensing method facilitates distinguishing closely spaced objects over realistic SNRs. Their work raises the intriguing question of whether sensing approaches structured more like a mammalian auditory system contains the necessary information for the hyper-resolution observed in behavioral tests. This research estimates sparse echo signatures using a gammatone filterbank decimation sensing method which loosely models the processing of the bat's auditory system. The decimated filterbank outputs are processed with [script-l](1) minimization. Simulations demonstrate that this model maintains higher resolution than the MF and significantly better detection performance than the IF for SNRs of 5-45 dB while undersampling the return signal by a factor of six.

High Performance, Robust Control of Flexible Space Structures: MSFC Center Director's Discretionary Fund

NASA Technical Reports Server (NTRS)

Whorton, M. S.

1998-01-01

Many spacecraft systems have ambitious objectives that place stringent requirements on control systems. Achievable performance is often limited because of difficulty of obtaining accurate models for flexible space structures. To achieve sufficiently high performance to accomplish mission objectives may require the ability to refine the control design model based on closed-loop test data and tune the controller based on the refined model. A control system design procedure is developed based on mixed H2/H(infinity) optimization to synthesize a set of controllers explicitly trading between nominal performance and robust stability. A homotopy algorithm is presented which generates a trajectory of gains that may be implemented to determine maximum achievable performance for a given model error bound. Examples show that a better balance between robustness and performance is obtained using the mixed H2/H(infinity) design method than either H2 or mu-synthesis control design. A second contribution is a new procedure for closed-loop system identification which refines parameters of a control design model in a canonical realization. Examples demonstrate convergence of the parameter estimation and improved performance realized by using the refined model for controller redesign. These developments result in an effective mechanism for achieving high-performance control of flexible space structures.

RS-34 Phoenix In-Space Propulsion System Applied to Active Debris Removal Mission

NASA Technical Reports Server (NTRS)

Esther, Elizabeth A.; Burnside, Christopher G.

2014-01-01

In-space propulsion is a high percentage of the cost when considering Active Debris Removal mission. For this reason it is desired to research if existing designs with slight modification would meet mission requirements to aid in reducing cost of the overall mission. Such a system capable of rendezvous, close proximity operations, and de-orbit of Envisat class resident space objects has been identified in the existing RS-34 Phoenix. RS-34 propulsion system is a remaining asset from the de-commissioned United States Air Force Peacekeeper program; specifically the pressure-fed storable bi-propellant Stage IV Post Boost Propulsion System. The National Aeronautics and Space Administration (NASA) Marshall Space Flight Center (MSFC) gained experience with the RS-34 propulsion system on the successful Ares I-X flight test program flown in the Ares I-X Roll control system (RoCS). The heritage hardware proved extremely robust and reliable and sparked interest for further utilization on other potential in-space applications. Subsequently, MSFC has obtained permission from the USAF to obtain all the remaining RS-34 stages for re-use opportunities. The MSFC Advanced Concepts Office (ACO) was commissioned to lead a study for evaluation of the Rocketdyne produced RS-34 propulsion system as it applies to an active debris removal design reference mission for resident space object targets including Envisat. Originally designed, the RS-34 Phoenix provided in-space six-degrees-of freedom operational maneuvering to deploy payloads at multiple orbital locations. The RS-34 Concept Study lead by sought to further understand application for a similar orbital debris design reference mission to provide propulsive capability for rendezvous, close proximity operations to support the capture phase of the mission, and deorbit of single or multiple large class resident space objects. Multiple configurations varying the degree of modification were identified to trade for dry mass optimization and propellant load. The results of the RS-34 Phoenix Concept Study show that the system is technically sufficient to successfully support all of the missions to rendezvous, capture, and de-orbit targets including Envisat and Hubble Space Telescope. The results and benefits of the RS-34 Orbital Debris Application Concept Study are presented in this paper.

CCTV Coverage Index Based on Surveillance Resolution and Its Evaluation Using 3D Spatial Analysis

PubMed Central

Choi, Kyoungah; Lee, Impyeong

2015-01-01

We propose a novel approach to evaluating how effectively a closed circuit television (CCTV) system can monitor a targeted area. With 3D models of the target area and the camera parameters of the CCTV system, the approach produces surveillance coverage index, which is newly defined in this study as a quantitative measure for surveillance performance. This index indicates the proportion of the space being monitored with a sufficient resolution to the entire space of the target area. It is determined by computing surveillance resolution at every position and orientation, which indicates how closely a specific object can be monitored with a CCTV system. We present full mathematical derivation for the resolution, which depends on the location and orientation of the object as well as the geometric model of a camera. With the proposed approach, we quantitatively evaluated the surveillance coverage of a CCTV system in an underground parking area. Our evaluation process provided various quantitative-analysis results, compelling us to examine the design of the CCTV system prior to its installation and understand the surveillance capability of an existing CCTV system. PMID:26389909

Phase III integrated water recovery testing at MSFC - Partially closed hygiene loop and open potable loop results and lessons learned

NASA Technical Reports Server (NTRS)

Bagdigian, R. M.; Traweek, M. S.; Griffith, G. K.; Griffin, M. R.

1991-01-01

A series of tests has been conducted at the NASA Marshall Space Flight Center (MSFC) to evaluate the performance of a predevelopment water recovery system. Potable, hygiene, and urine reclamation subsystems were integrated with end-use equipment items and successfully operated in open and partially closed-loop modes, with man-in-the-loop, for a total of 28 days. Several significant subsystem physical anomalies were encountered during testing. Reclaimed potable and hygiene water generally met the current Space Station Freedom (SSF) water quality specifications for inorganic and microbiological constituents, but exceeded the maximum allowable concentrations for Total Organic Carbon (TOC). This paper summarizes the test objectives, system design, test activities/protocols, significant results/anomalies, and major lessons learned.

Twist-induced guidance in coreless photonic crystal fiber: A helical channel for light.

PubMed

Beravat, Ramin; Wong, Gordon K L; Frosz, Michael H; Xi, Xiao Ming; Russell, Philip St J

2016-11-01

A century ago, Einstein proposed that gravitational forces were the result of the curvature of space-time and predicted that light rays would deflect when passing a massive celestial object. We report that twisting the periodically structured "space" within a coreless photonic crystal fiber creates a helical channel where guided modes can form despite the absence of any discernible core structure. Using a Hamiltonian optics analysis, we show that the light rays follow closed spiral or oscillatory paths within the helical channel, in close analogy with the geodesics of motion in a two-dimensional gravitational field. The mode diameter shrinks, and its refractive index rises, as the twist rate increases. The birefringence, orbital angular momentum, and dispersion of these unusual modes are explored.

Computational methods in the exploration of the classical and statistical mechanics of celestial scale strings: Rotating Space Elevators

NASA Astrophysics Data System (ADS)

Knudsen, Steven; Golubovic, Leonardo

2015-04-01

With the advent of ultra-strong materials, the Space Elevator has changed from science fiction to real science. We discuss computational and theoretical methods we developed to explore classical and statistical mechanics of rotating Space Elevators (RSE). An RSE is a loopy string reaching deep into outer space. The floppy RSE loop executes a motion which is nearly a superposition of two rotations: geosynchronous rotation around the Earth, and yet another faster rotational motion of the string which goes on around a line perpendicular to the Earth at its equator. Strikingly, objects sliding along the RSE loop spontaneously oscillate between two turning points, one of which is close to the Earth (starting point) whereas the other one is deeply in the outer space. The RSE concept thus solves a major problem in space elevator science which is how to supply energy to the climbers moving along space elevator strings. The exploration of the dynamics of a floppy string interacting with objects sliding along it has required development of novel finite element algorithms described in this presentation. We thank Prof. Duncan Lorimer of WVU for kindly providing us access to his computational facility.

Predicting Space Weather Effects on Close Approach Events

NASA Technical Reports Server (NTRS)

Hejduk, Matthew D.; Newman, Lauri K.; Besser, Rebecca L.; Pachura, Daniel A.

2015-01-01

The NASA Robotic Conjunction Assessment Risk Analysis (CARA) team sends ephemeris data to the Joint Space Operations Center (JSpOC) for conjunction assessment screening against the JSpOC high accuracy catalog and then assesses risk posed to protected assets from predicted close approaches. Since most spacecraft supported by the CARA team are located in LEO orbits, atmospheric drag is the primary source of state estimate uncertainty. Drag magnitude and uncertainty is directly governed by atmospheric density and thus space weather. At present the actual effect of space weather on atmospheric density cannot be accurately predicted because most atmospheric density models are empirical in nature, which do not perform well in prediction. The Jacchia-Bowman-HASDM 2009 (JBH09) atmospheric density model used at the JSpOC employs a solar storm active compensation feature that predicts storm sizes and arrival times and thus the resulting neutral density alterations. With this feature, estimation errors can occur in either direction (i.e., over- or under-estimation of density and thus drag). Although the exact effect of a solar storm on atmospheric drag cannot be determined, one can explore the effects of JBH09 model error on conjuncting objects' trajectories to determine if a conjunction is likely to become riskier, less risky, or pass unaffected. The CARA team has constructed a Space Weather Trade-Space tool that systematically alters the drag situation for the conjuncting objects and recalculates the probability of collision for each case to determine the range of possible effects on the collision risk. In addition to a review of the theory and the particulars of the tool, the different types of observed output will be explained, along with statistics of their frequency.

KENNEDY SPACE CENTER, FLA. - At the KSC Launch Pad 39A, two members of the payload closeout crew check equipment as the doors are just about ready to be closed. The Payload inside the bay of Discovery, the orbiter for the STS-82 mission, is ready for the launch of the second Hubble Space Telescope service mission. The payload consists of the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) that will be installed, Fine Guidance Sensor #1 (FGS-1), and the Space Telescope Imaging Spectrograph (STIS) to be installed. The STS-82 will launch with a crew of seven at 3:54 a.m. EST, Feb. 11, 1997. The launch window is 65 minutes in duration. The Mission Commander for STS-82 is Ken Bowersox. The purpose of the mission is to upgrade the scientific capabilities, service or replace aging components on the Telescope and provide a reboost to the optimum altitude.

NASA Image and Video Library

1997-02-07

KENNEDY SPACE CENTER, FLA. - At the KSC Launch Pad 39A, two members of the payload closeout crew check equipment as the doors are just about ready to be closed. The Payload inside the bay of Discovery, the orbiter for the STS-82 mission, is ready for the launch of the second Hubble Space Telescope service mission. The payload consists of the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) that will be installed, Fine Guidance Sensor #1 (FGS-1), and the Space Telescope Imaging Spectrograph (STIS) to be installed. The STS-82 will launch with a crew of seven at 3:54 a.m. EST, Feb. 11, 1997. The launch window is 65 minutes in duration. The Mission Commander for STS-82 is Ken Bowersox. The purpose of the mission is to upgrade the scientific capabilities, service or replace aging components on the Telescope and provide a reboost to the optimum altitude.

KENNEDY SPACE CENTER, FLA. - The Payload is seen inside of the Bay just before the doors are closed for flight at KSC's Launch Pad 39A. Discovery, the orbiter for the STS-82 mission, is ready for the launch of the second Hubble Space Telescope service mission. The payload consists of the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) that will be installed, Fine Guidance Sensor #1 (FGS-1), and the Space Telescope Imaging Spectrograph (STIS) to be installed. The STS-82 will launch with a crew of seven at 3:54 a.m. EST, Feb. 11, 1997. The launch window is 65 minutes in duration. The Mission Commander for STS-82 is Ken Bowersox. The purpose of the mission is to upgrade the scientific capabilities, service or replace aging components on the Telescope, and provide a reboost to the optimum altitude.

NASA Image and Video Library

1997-02-07

KENNEDY SPACE CENTER, FLA. - The Payload is seen inside of the Bay just before the doors are closed for flight at KSC's Launch Pad 39A. Discovery, the orbiter for the STS-82 mission, is ready for the launch of the second Hubble Space Telescope service mission. The payload consists of the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) that will be installed, Fine Guidance Sensor #1 (FGS-1), and the Space Telescope Imaging Spectrograph (STIS) to be installed. The STS-82 will launch with a crew of seven at 3:54 a.m. EST, Feb. 11, 1997. The launch window is 65 minutes in duration. The Mission Commander for STS-82 is Ken Bowersox. The purpose of the mission is to upgrade the scientific capabilities, service or replace aging components on the Telescope, and provide a reboost to the optimum altitude.

Study of the X-Ray Diagnosis of Unstable Pelvic Fracture Displacements in Three-Dimensional Space and its Application in Closed Reduction.

PubMed

Shi, Chengdi; Cai, Leyi; Hu, Wei; Sun, Junying

2017-09-19

ABSTRACTS Objective: To study the method of X-ray diagnosis of unstable pelvic fractures displaced in three-dimensional (3D) space and its clinical application in closed reduction. Five models of hemipelvic displacement were made in an adult pelvic specimen. Anteroposterior radiographs of the pelvis were analyzed in PACS. The method of X-ray diagnosis was applied in closed reductions. From February 2012 to June 2016, 23 patients (15 men, 8 women; mean age, 43.4 years) with unstable pelvic fractures were included. All patients were treated by closed reduction and percutaneous cannulate screw fixation of the pelvic ring. According to Tile's classification, the patients were classified into type B1 in 7 cases, B2 in 3, B3 in 3, C1 in 5, C2 in 3, and C3 in 2. The operation time and intraoperative blood loss were recorded. Postoperative images were evaluated by Matta radiographic standards. Five models of displacement were made successfully. The X-ray features of the models were analyzed. For clinical patients, the average operation time was 44.8 min (range, 20-90 min) and the average intraoperative blood loss was 35.7 (range, 20-100) mL. According to the Matta standards, 7 cases were excellent, 12 cases were good, and 4 were fair. The displacements in 3D space of unstable pelvic fractures can be diagnosed rapidly by X-ray analysis to guide closed reduction, with a satisfactory clinical outcome.

Mission concept and autonomy considerations for active Debris removal

NASA Astrophysics Data System (ADS)

Peters, Susanne; Pirzkall, Christoph; Fiedler, Hauke; Förstner, Roger

2016-12-01

Over the last 60 years, Space Debris has become one of the main challenges for the safe operation of satellites in low Earth orbit. To address this threat, guidelines that include a limited debris release during normal operations, minimization of the potential for on-orbit break-ups and post mission disposal have begun to be implemented. However, for the long-term, the amount of debris will still increase due to fragments created by collisions of objects in space. The active removal of space debris of at least five large objects per years is therefore recommended, but not yet included in those guidelines. Even though various technical concepts have been developed over the last years, the question on how to make them reliable and safe or how to finance such mission has not been answered. This paper addresses the first two topics. With Space Debris representing an uncooperative and possibly tumbling target, close proximity becomes absolutely critical, especially when an uninterrupted connection to the ground station is not ensured. This paper therefore defines firstly a mission to remove at least five large objects and secondly introduces a preliminary autonomy concept fitted for this mission.

Discrete Jordan curve theorem

NASA Astrophysics Data System (ADS)

Chen, Li

1999-09-01

According to a general definition of discrete curves, surfaces, and manifolds (Li Chen, 'Generalized discrete object tracking algorithms and implementations, ' In Melter, Wu, and Latecki ed, Vision Geometry VI, SPIE Vol. 3168, pp 184 - 195, 1997.). This paper focuses on the Jordan curve theorem in 2D discrete spaces. The Jordan curve theorem says that a (simply) closed curve separates a simply connected surface into two components. Based on the definition of discrete surfaces, we give three reasonable definitions of simply connected spaces. Theoretically, these three definition shall be equivalent. We have proved the Jordan curve theorem under the third definition of simply connected spaces. The Jordan theorem shows the relationship among an object, its boundary, and its outside area. In continuous space, the boundary of an mD manifold is an (m - 1)D manifold. The similar result does apply to regular discrete manifolds. The concept of a new regular nD-cell is developed based on the regular surface point in 2D, and well-composed objects in 2D and 3D given by Latecki (L. Latecki, '3D well-composed pictures,' In Melter, Wu, and Latecki ed, Vision Geometry IV, SPIE Vol 2573, pp 196 - 203, 1995.).

Comparison Analysis of Recognition Algorithms of Forest-Cover Objects on Hyperspectral Air-Borne and Space-Borne Images

NASA Astrophysics Data System (ADS)

Kozoderov, V. V.; Kondranin, T. V.; Dmitriev, E. V.

2017-12-01

The basic model for the recognition of natural and anthropogenic objects using their spectral and textural features is described in the problem of hyperspectral air-borne and space-borne imagery processing. The model is based on improvements of the Bayesian classifier that is a computational procedure of statistical decision making in machine-learning methods of pattern recognition. The principal component method is implemented to decompose the hyperspectral measurements on the basis of empirical orthogonal functions. Application examples are shown of various modifications of the Bayesian classifier and Support Vector Machine method. Examples are provided of comparing these classifiers and a metrical classifier that operates on finding the minimal Euclidean distance between different points and sets in the multidimensional feature space. A comparison is also carried out with the " K-weighted neighbors" method that is close to the nonparametric Bayesian classifier.

Heat flow in variable polarity plasma arc welds

NASA Technical Reports Server (NTRS)

Abdelmessih, Amanie N.

1992-01-01

The space shuttle external tank and the space station Freedom are fabricated by the variable polarity plasma arc (VPPA) welding. Heat sink effects (taper) are observed when there are irregularities in the work-piece configuration especially if these irregularities are close to the weld bead. These heat sinks affect the geometry of the weld bead, and in extreme cases they could cause defects such as incomplete fusion. Also, different fixtures seem to have varying heat sink effects. The objective of the previous, present, and consecutive research studies is to investigate the effect of irregularities in the work-piece configuration and fixture differences on the weld bead geometry with the ultimate objective to compensate automatically for the heat sink effects and achieve a perfect weld.

Pragmatic open space box utilization: asteroid survey model using distributed objects management based articulation (DOMBA)

NASA Astrophysics Data System (ADS)

Mohammad, Atif Farid; Straub, Jeremy

2015-05-01

A multi-craft asteroid survey has significant data synchronization needs. Limited communication speeds drive exacting performance requirements. Tables have been used in Relational Databases, which are structure; however, DOMBA (Distributed Objects Management Based Articulation) deals with data in terms of collections. With this, no read/write roadblocks to the data exist. A master/slave architecture is created by utilizing the Gossip protocol. This facilitates expanding a mission that makes an important discovery via the launch of another spacecraft. The Open Space Box Framework facilitates the foregoing while also providing a virtual caching layer to make sure that continuously accessed data is available in memory and that, upon closing the data file, recharging is applied to the data.

Evidence for close-range hunting by last interglacial Neanderthals.

PubMed

Gaudzinski-Windheuser, Sabine; Noack, Elisabeth S; Pop, Eduard; Herbst, Constantin; Pfleging, Johannes; Buchli, Jonas; Jacob, Arne; Enzmann, Frieder; Kindler, Lutz; Iovita, Radu; Street, Martin; Roebroeks, Wil

2018-07-01

Animal resources have been part of hominin diets since around 2.5 million years ago, with sharp-edged stone tools facilitating access to carcasses. How exactly hominins acquired animal prey and how hunting strategies varied through time and space is far from clear. The oldest possible hunting weapons known from the archaeological record are 300,000 to 400,000-year-old sharpened wooden staves. These may have been used as throwing and/or close-range thrusting spears, but actual data on how such objects were used are lacking, as unambiguous lesions caused by such weapon-like objects are unknown for most of human prehistory. Here, we report perforations observed on two fallow deer skeletons from Neumark-Nord, Germany, retrieved during excavations of 120,000-year-old lake shore deposits with abundant traces of Neanderthal presence. Detailed studies of the perforations, including micro-computed tomography imaging and ballistic experiments, demonstrate that they resulted from the close-range use of thrusting spears. Such confrontational ways of hunting require close cooperation between participants, and over time may have shaped important aspects of hominin biology and behaviour.

River channel bars and dunes - Theory of kinematic waves

USGS Publications Warehouse

Langbein, Walter Basil; Leopold, Luna Bergere

1968-01-01

A kinematic wave is a grouping cf moving objects in zones along a flow path and through which the objects pass. These concentrations may be characterized by a simple relation between the speed of the moving objects and their spacing as a result of interaction between them.Vehicular traffic has long been known to have such properties. Data are introduced to show that beads carried by flowing water in a narrow flume behave in an analogous way. The flux or transport of objects in a single lane of traffic is greatest when the objects are spaced about two diameters apart; beads in a single-lane flume as well as highway traffic conform to this property.By considering the sand in a pipe or flume to a depth affected by dune movement, it is shown that flux-concentration curves similar to the previously known cases can be constructed from experimental data. From the kinematic point of view, concentration of particles in dunes and other wave bed forms results when particles in transport become more numerous or closely spaced and interact to reduce the effectiveness of the ambient water to move them.Field observations over a 5-year period are reported in which individual rocks were painted for identification and placed at various spacings on the bed of ephemeral stream in New Mexico, to study the effect of storm flows on rock movement. The data on about 14,000 rocks so observed show the effect of variable spacing which is quantitatively as well as qualitatively comparable to the spacing effect on small glass beads in a flume. Dunes and gravel bars may be considered kinematic waves caused by particle interaction, and certain of their properties can be related to the characteristics of the flux-concentration curve.

Atmosphere Resource Recovery and Environmental Monitoring

NASA Technical Reports Server (NTRS)

Roman, Monsi; Howard, David

2015-01-01

Atmosphere Resource Recovery and Environmental Monitoring (ARREM) is a project focused on evolving existing and maturing emerging 'closed loop' atmosphere revitalization (AR) life support systems that produce clean, breathable air for crewmembers, and developing a suite of low mass, low power environmental monitors to detect and measure air- and waterborne constituents and contaminants. The objective is to improve reliability and efficiency, reduce mass and volume, and increase recovery of oxygen from carbon dioxide created by human metabolism from 43% to greater than 90%. The technology developments under ARREM are vital to extending human space missions from low-Earth orbit like the International Space Station to destinations deeper into space such as Mars where dependency on Earth for resupply of maintenance items and critical life support elements such as water and oxygen is not possible. The primary goal of the ARREM project is to demonstrate that systems meet the more stringent performance parameters for deep space exploration and are compatible with other systems within closed loop life support through a series of integrated tests performed in an environmental test chamber capable of simulating human metabolic activities and measuring systems outputs.

Optimization of the structural and control system for LSS with reduced-order model

NASA Technical Reports Server (NTRS)

Khot, N. S.

1989-01-01

The objective is the simultaneous design of the structural and control system for space structures. The minimum weight of the structure is the objective function, and the constraints are placed on the closed loop distribution of the frequencies and the damping parameters. The controls approach used is linear quadratic regulator with constant feedback. A reduced-order control system is used. The effect of uncontrolled modes is taken into consideration by the model error sensitivity suppression (MESS) technique which modified the weighting parameters for the control forces. For illustration, an ACOSS-FOUR structure is designed for a different number of controlled modes with specified values for the closed loop damping parameters and frequencies. The dynamic response of the optimum designs for an initial disturbance is compared.

Developments in TurboBrayton Technology for Low Temperature Applications

NASA Technical Reports Server (NTRS)

Swift, W. L.; Zagarola, M. V.; Nellis, G. F.; McCormick, J. A.; Gibbon, Judy

1999-01-01

A single stage reverse Brayton cryocooler using miniature high-speed turbomachines recently completed a successful space shuttle test flight demonstrating its capabilities for use in cooling the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope (HST). The NICMOS CryoCooler (NCC) is designed for a cooling load of about 8 W at 65 K, and comprises a closed loop cryocooler coupled to an independent cryogenic circulating loop. Future space applications involve instruments that will require 5 mW to 200 mW of cooling at temperatures between 4 K and 10 K. This paper discusses the extension of Turbo-Brayton technology to meet these requirements.

Development and Operation of the Microshutter Array System

NASA Technical Reports Server (NTRS)

Jhabvala, M. D.; Franz, D.; King, T.; Kletetschka, G.; Kutyrev, A. S.; Li, M. J.

2008-01-01

The microshutter array (MSA) is a key component in the James Webb Space Telescope Near Infrared Spectrometer (NIRSpec) instrument. The James Webb Space Telescope is the next generation of a space-borne astronomy platform that is scheduled to be launched in 2013. However, in order to effectively operate the array and meet the severe operational requirements associated with a space flight mission has placed enormous constraints on the microshutter array subsystem. This paper will present an overview and description of the entire microshutter subsystem including the microshutter array, the hybridized array assembly, the integrated CMOS electronics, mechanical mounting module and the test methodology and performance of the fully assembled microshutter subsystem. The NIRSpec is a European Space Agency (ESA) instrument requiring four fully assembled microshutter arrays, or quads, which are independently addressed to allow for the imaging of selected celestial objects onto the two 4 mega pixel IR detectors. Each microshutter array must have no more than approx.8 shutters which are failed in the open mode (depending on how many are failed closed) out of the 62,415 (365x171) total number of shutters per array. The driving science requirement is to be able to select up to 100 objects at a time to be spectrally imaged at the focal plane. The spectrum is dispersed in the direction of the 171 shutters so if there is an unwanted open shutter in that row the light from an object passing through that failed open shutter will corrupt the spectrum from the intended object.

Objects of attention, objects of perception.

PubMed

Avrahami, J

1999-11-01

Four experiments were conducted, to explore the notion of objects in perception. Taking as a starting point the effects of display content on rapid attention transfer and manipulating curvature, closure, and processing time, a link between objects of attention and objects of perception is proposed. In Experiment 1, a number of parallel, equally spaced, straight lines facilitated attention transfer along the lines, relative to transfer across the lines. In Experiment 2, with curved, closed-contour shapes, no "same-object" facilitation was observed. However, when a longer time interval was provided, in Experiment 3, a same-object advantage started to emerge. In Experiment 4, using the same curved shapes but in a non-speeded distance estimation task, a strong effect of objects was observed. It is argued that attention transfer is facilitated by line tracing but that line tracing is encouraged by objects.

46 CFR 72.15-15 - Ventilation for closed spaces.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 3 2011-10-01 2011-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings to...

46 CFR 72.15-15 - Ventilation for closed spaces.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 3 2013-10-01 2013-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings to...

46 CFR 72.15-15 - Ventilation for closed spaces.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 3 2010-10-01 2010-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings to...

46 CFR 72.15-15 - Ventilation for closed spaces.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 3 2014-10-01 2014-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings to...

46 CFR 72.15-15 - Ventilation for closed spaces.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 3 2012-10-01 2012-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings to...

The James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Mather, John C.

2004-01-01

The James Webb Space Telescope (JWST) will extend the discoveries of the Hubble Space Telescope (HST) and the Spitzer Space Telescope (SST) by deploying a large cooled infrared telescope around the Sun-Earth Lagrange point L2. With a 6 m aperture and three instruments covering the wavelength range from 0.6 to 28 microns, it will provide sensitivities orders of magnitude better than any other facilities. It is intended to observe the light from the first galaxies and the first supernovae, the assembly of galaxies, and the formation and evolution of stars and planetary systems. In this talk I will review the scientific objectives and the ability of the system to meet them. I will close with a summary of possible future IR space missions, ranging from the far IR to planet-finding coronagraphs and interferometers

PEPE is installed on Deep Space 1 in the PHSF

NASA Technical Reports Server (NTRS)

1998-01-01

The Plasma Experiment for Planetary Exploration (PEPE), one of two advanced science experiments flying on the Deep Space l mission, is prepared for installation on the spacecraft in the Payload Hazardous Servicing Facility. PEPE combines several instruments that study space plasma in one compact 13-pound (6- kilogram) package. Space plasma is composed of charged particles, most of which flow outward from the Sun. The first flight in NASA's New Millennium Program, Deep Space 1 is designed to validate 12 new technologies for scientific space missions of the next century. The spacecraft is scheduled to launch during a period opening Oct. 15 and closing Nov. 10, 1998. Most of its mission objectives will be completed within the first two months. A near-earth asteroid, 1992 KD, has also been selected for a possible flyby.

Discrimination of Closely-Spaced Geosynchronous Satellites - Phase Curve Analysis & New Small Business Innovative Research (SBIR) Efforts

NASA Astrophysics Data System (ADS)

Levan, P.

2010-09-01

Geosynchronous objects appear as unresolved blurs even when observed with the largest ground-based telescopes. Due to the lack of any spatial detail, two or more objects appearing at similar brightness levels within the spectral bandpass they are observed are difficult to distinguish. Observing a changing pattern of such objects from one time epoch to another showcases the deficiencies in associating individual objects before and after the configuration change. This paper explores solutions to this deficiency in the form of spectral (under small business innovative research) and phase curve analyses. The extension of the technique to phase curves proves to be a powerful new capability.

ESA activities on satellite laser ranging to non-cooperative objects

NASA Astrophysics Data System (ADS)

Flohrer, Tim; Krag, Holger; Funke, Quirin; Jilete, Beatriz; Mancas, Alexandru

2016-07-01

Satellite laser ranging (SLR) to non-cooperative objects is an emerging technology that can contribute significantly to operational, modelling and mitigation needs set by the space debris population. ESA is conducting various research and development activities in SLR to non-cooperative objects. ESA's Space Situational Awareness (SSA) program supports specific activities in the Space Surveillance and Tracking (SST) segment. Research and development activities with operational aspects are run by ESA's Space Debris Office. At ESA SSA/SST comprises detecting, cataloguing and predicting the objects orbiting the Earth, and the derived applications. SST aims at facilitating research and development of sensor and data processing technologies and of related common components while staying complementary with, and in support of, national and multi-national European initiatives. SST promotes standardisation and interoperability of the technology developments. For SLR these goals are implemented through researching, developing, and deploying an expert centre. This centre shall coordinate the contribution of system-external loosely connected SLR sensors, and shall provide back calibration and expert evaluation support to the sensors. The Space Debris Office at ESA is responsible for all aspects related to space debris in the Agency. It is in charge of providing operational support to ESA and third party missions. Currently, the office studies the potential benefits of laser ranging to space debris objects to resolve close approaches to active satellites, to improve re-entry predictions of time and locations, and the more general SLR support during contingency situations. The office studies the determination of attitude and attitude motion of uncooperative objects with special focus on the combination of SLR, light-curve, and radar imaging data. Generating sufficiently precise information to allow for the acquisition of debris objects by a SLR sensor in a stare-and-chase scenario, or from externally provided orbital information, is also investigated. In our paper we will outline the motivation and objectives, as well as detail the current status of the various and parallel SLR-related SST and Space Debris Office activities at ESA. We will provide an overview on plans for SLR activities in research and development and in operational support. Current gaps in the standardisation of data exchange and sensor interfaces will be addressed, reflecting the need of coordinating multiple stations in all tasks.

IMAX camera in payload bay

NASA Image and Video Library

1995-12-20

STS074-361-035 (12-20 Nov 1995) --- This medium close-up view centers on the IMAX Cargo Bay Camera (ICBC) and its associated IMAX Camera Container Equipment (ICCE) at its position in the cargo bay of the Earth-orbiting Space Shuttle Atlantis. With its own ?space suit? or protective covering to protect it from the rigors of space, this version of the IMAX was able to record scenes not accessible with the in-cabin cameras. For docking and undocking activities involving Russia?s Mir Space Station and the Space Shuttle Atlantis, the camera joined a variety of in-cabin camera hardware in recording the historical events. IMAX?s secondary objectives were to film Earth views. The IMAX project is a collaboration between NASA, the Smithsonian Institution?s National Air and Space Museum (NASM), IMAX Systems Corporation, and the Lockheed Corporation to document significant space activities and promote NASA?s educational goals using the IMAX film medium.

46 CFR 190.15-10 - Ventilation for closed spaces.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Ventilation for closed spaces. 190.15-10 Section 190.15... CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-10 Ventilation for closed spaces. (a) All enclosed spaces... chemical laboratories, scientific laboratories, chemical storerooms, and machinery spaces and for closing...

46 CFR 190.15-10 - Ventilation for closed spaces.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Ventilation for closed spaces. 190.15-10 Section 190.15... CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-10 Ventilation for closed spaces. (a) All enclosed spaces... chemical laboratories, scientific laboratories, chemical storerooms, and machinery spaces and for closing...

46 CFR 190.15-10 - Ventilation for closed spaces.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Ventilation for closed spaces. 190.15-10 Section 190.15... CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-10 Ventilation for closed spaces. (a) All enclosed spaces... chemical laboratories, scientific laboratories, chemical storerooms, and machinery spaces and for closing...

46 CFR 190.15-10 - Ventilation for closed spaces.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Ventilation for closed spaces. 190.15-10 Section 190.15... CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-10 Ventilation for closed spaces. (a) All enclosed spaces... chemical laboratories, scientific laboratories, chemical storerooms, and machinery spaces and for closing...

46 CFR 190.15-10 - Ventilation for closed spaces.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Ventilation for closed spaces. 190.15-10 Section 190.15... CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-10 Ventilation for closed spaces. (a) All enclosed spaces... chemical laboratories, scientific laboratories, chemical storerooms, and machinery spaces and for closing...

A scheme for lensless X-ray microscopy combining coherent diffraction imaging and differential corner holography.

PubMed

Capotondi, F; Pedersoli, E; Kiskinova, M; Martin, A V; Barthelmess, M; Chapman, H N

2012-10-22

We successfully use the corners of a common silicon nitride supporting window in lensless X-ray microscopy as extended references in differential holography to obtain a real space hologram of the illuminated object. Moreover, we combine this method with the iterative phasing techniques of coherent diffraction imaging to enhance the spatial resolution on the reconstructed object, and overcome the problem of missing areas in the collected data due to the presence of a beam stop, achieving a resolution close to 85 nm.

High-energy radiation from the relativistic jet of Cygnus X-3

NASA Astrophysics Data System (ADS)

Cerutti, B.; Dubus, G.; Henri, G.

2010-12-01

Cygnus X-3 is an accreting high-mass X-ray binary composed of a Wolf-Rayet star and an unknown compact object, possibly a black hole. The gamma-ray space telescope Fermi found definitive evidence that high-energy emission is produced in this system. We propose a scenario to explain the GeV gamma-ray emission in Cygnus X-3. In this model, energetic electron-positron pairs are accelerated at a specific location in the relativistic jet, possibly related to a recollimation shock, and upscatter the stellar photons to high energies. The comparison with Fermi observations shows that the jet should be inclined close to the line of sight and pairs should not be located within the system. Energetically speaking, a massive compact object is favored. We report also on our investigations of the gamma-ray absorption of GeV photons with the radiation emitted by a standard accretion disk in Cygnus X-3. This study shows that the gamma-ray source should not lie too close to the compact object.

The Role of Presented Objects in Deriving Color Preference Criteria from Psychophysical Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Royer, Michael P.; Wei, Minchen

Of the many “components” of a color rendering measure, one is perhaps the most important: the set of color samples (spectral reflectance functions) that are employed as a standardized means of evaluating and rating a light source. At the same time, a standardized set of color samples can never apply perfectly to a real space or a real set of observed objects, meaning there will always be some level of mismatch between the predicted and observed color shifts. This mismatch is important for lighting specifiers to consider, but even more critical for experiments that seek to evaluate the relationship betweenmore » color rendering measures and human perception. This article explores how the color distortions of three possible experimental object sets compare to the color distortions predicted using the color evaluation samples of IES TM-30-15 (TM-30). The experimental object sets include those from Royer and colleagues [2016], a set of produce (10 fruits and vegetables), and the X-rite Color Checker Classic. The differences are traced back to properties of the samples sets, such as the coverage of color space, average chroma level, and specific spectral features. The consequence of the differences, that the visual evaluation is based on color distortions that are substantially different from what is predicted, can lead to inaccurate criteria or models of a given perception, such as preference. To minimize the error in using criteria or models when specifying color rendering attributes for a given application, the criteria or models should be developed using a set of experimental objects that matches the typical objects of the application as closely as possible. Alternatively, if typical objects of an application cannot be reasonably determined, an object set that matches the distortions predicted by TM-30 as close as possible is likely to provide the most meaningful results.« less

NASA 30,000 hour test demonstration of closed Brayton cycle reliability

NASA Technical Reports Server (NTRS)

Mccormick, J. E.; Dunn, J. H.

1977-01-01

Four Brayton rotating units (BRU) developed by an American company were tested in connection with studies concerning the feasibility to use closed Brayton power conversion systems for space applications. The rotating assembly operates at a speed of 36,000 rpm and consists of a radial outflow compressor, a four-pole Rice alternator/motor, and a radial inflow turbine. The cycle working fluid consists of a mixture of helium and xenon. After 20,000 hours of operation, there was no apparent wear on failure mode to prevent attainment of the 5-year BRU design life objective.

Elastic Distribution of Microshutters, Measurements Obtainable on James Web Space Telescope

NASA Technical Reports Server (NTRS)

Kletetschka, Gunther; King, Todd; Mikula, Vilem

2008-01-01

Spectrographic astronomy measurements in the near-infrared region will be done by functional two-dimensional microshutter arrays that are being fabricated at the NASA Goddard Space Flight Center for the James Webb Space Telescope (JWST). These micro-shutter arrays will represent the first mission-critical MEMS devices to be flown in space. JWST will use microshutter arrays to select focal plane object. 2-D programmable aperture masks of more than 200,000 elements select such space object. The use of silicon wafer material promises high efficiency and high contrast. Microshutter operation temperature is around 35K. Microshutter arrays are fabricated as close-packed silicon nitride membranes with a unit cell size of 105 x 204 micrometers. A layer of magnetic material is deposited onto each shutter. Individual shutters are equipped with a torsion flexure. Reactive ion etching (RIE) releases the shutters so they can open up to 90 degrees using the torsion flexure. Shutter rotation is initiated into a silicon support structure via an external magnetic field. Two electrically independent aluminum electrodes are deposited, one onto each shutter and another onto the support structure side-wall, permitting electrostatic latching and 2-D addressing to hold specific shutters open via external electronics.

Feasibility of performing space surveillance tasks with a proposed space-based optical architecture

NASA Astrophysics Data System (ADS)

Flohrer, Tim; Krag, Holger; Klinkrad, Heiner; Schildknecht, Thomas

Under ESA contract an industrial consortium including Aboa Space Research Oy (ASRO), the Astronomical Institute of the University of Bern (AIUB), and the Dutch National Aerospace Laboratory (NLR), proposed the observation concept, developed a suitable sensor architecture, and assessed the performance of a space-based optical (SBO) telescope in 2005. The goal of the SBO instrumentation was to analyse how the existing knowledge gap in the space debris population in the millimetre and centimetre regime may be closed by means of a passive op-tical instrument. SBO was requested to provide statistical information on the space debris population, in terms of number of objects and size distribution. The SBO was considered to be a cost-efficient instrumentation of 20 cm aperture and 6 deg field-of-view with flexible integration requirements. It should be possible to integrate the SBO easily as a secondary payload on satellites launched into low-Earth orbits (LEO), or into geostationary orbit (GEO). Thus the selected mission concept only allowed for fix-mounted telescopes, and the pointing direction could be requested freely. It was shown in the performance analysis that the statistical information on small-sized space debris can only be collected if the observation ranges are comparatively small. Two of the most promising concepts were to observe objects in LEO from a sensor placed into a sun-synchronous LEO, while objects in GEO should be observed from a GEO satellite. Since 2007 ESA focuses space surveillance and tracking activities in the Space Situational Awareness (SSA) preparatory program. Ground-based radars and optical telescopes are stud-ied for the build-up and to maintenance of a catalogue of objects. In this paper we analyse how the SBO architecture could contribute to the space surveillance tasks survey and tracking. We assume that the SBO instrumentation is placed into a circular sun-synchronous orbit at 800 km altitude. We discuss the observation conditions of objects at higher altitude, such as GEO and Medium-Earth Orbits (MEO). Of particular interest are the radiometric performance from which we derive the detectable object diameters, the coverage of a reference population, and the covered arc lengths of individual objects. The latter is of particular interest for the simu-lation of the orbit determination, correlation, and cataloguing. Assuming realistic noise levels known from the SBO design we simulate first orbit determination of unknown objects (surveys) and orbit improvements (tracking) for sample objects. We use a simulation environment that comprises the ESA Program for Radar and Optical Observation Forecasting (PROOF) in the version 2005 and AIUB's program system CelMech. ESA's MASTER-2005 serves as reference population for all analyses.

NASA's Planetary Defense Coordination Office at NASA HQ

NASA Astrophysics Data System (ADS)

Daou, D.; Johnson, L.; Fast, K. E.; Landis, R.; Friedensen, V. P.; Kelley, M.

2017-09-01

NASA and its partners maintain a watch for near-Earth objects (NEOs), asteroids and comets that pass close to the Earth, as part of an ongoing effort to discover, catalog, and characterize these bodies. The PDCO is responsible for: • Ensuring the early detection of potentially hazardous objects (PHOs) - asteroids and comets whose orbit are predicted to bring them within 0.05 Astronomical Units of Earth; and of a size large enough to reach Earth's surface - that is, greater than perhaps 30 to 50 meters; • Tracking and characterizing PHOs and issuing warnings about potential impacts; • Providing timely and accurate communications about PHOs; and • Performing as a lead coordination node in U.S. Government planning for response to an actual impact threat. The PDCO collaborates with other U.S. Government agencies, other national and international agencies, and professional and amateur astronomers around the world. The PDCO also is responsible for facilitating communications between the science community and the public should any potentially hazardous NEO be discovered. In addition, the PDCO works closely with the United Nations Office of Outer Space Affairs, its Committee on the Peaceful Uses of Outer Space, and its Action Team on Near Earth Objects (also known as Action Team 14). The PDCO is a leading member of the International Asteroid Warning Network (IAWN) and the Space Missions Planning Advisory Group (SMPAG), multinational endeavors recommended by the United Nations for an international response to the NEO impact hazard and established and operated by the spacecapable nations. The PDCO also communicates with the scientific community through channels such as NASA's Small Bodies Assessment Group (SBAG). In this talk, we will provide an update to the office's various efforts and new opportunities for partnerships in the continuous international effort for Planetary Defense.

Distance-dependent processing of pictures and words.

PubMed

Amit, Elinor; Algom, Daniel; Trope, Yaacov

2009-08-01

A series of 8 experiments investigated the association between pictorial and verbal representations and the psychological distance of the referent objects from the observer. The results showed that people better process pictures that represent proximal objects and words that represent distal objects than pictures that represent distal objects and words that represent proximal objects. These results were obtained with various psychological distance dimensions (spatial, temporal, and social), different tasks (classification and categorization), and different measures (speed of processing and selective attention). The authors argue that differences in the processing of pictures and words emanate from the physical similarity of pictures, but not words, to the referents. Consequently, perceptual analysis is commonly applied to pictures but not to words. Pictures thus impart a sense of closeness to the referent objects and are preferably used to represent such objects, whereas words do not convey proximity and are preferably used to represent distal objects in space, time, and social perspective.

Supervisory autonomous local-remote control system design: Near-term and far-term applications

NASA Technical Reports Server (NTRS)

Zimmerman, Wayne; Backes, Paul

1993-01-01

The JPL Supervisory Telerobotics Laboratory (STELER) has developed a unique local-remote robot control architecture which enables management of intermittent bus latencies and communication delays such as those expected for ground-remote operation of Space Station robotic systems via the TDRSS communication platform. At the local site, the operator updates the work site world model using stereo video feedback and a model overlay/fitting algorithm which outputs the location and orientation of the object in free space. That information is relayed to the robot User Macro Interface (UMI) to enable programming of the robot control macros. The operator can then employ either manual teleoperation, shared control, or supervised autonomous control to manipulate the object under any degree of time-delay. The remote site performs the closed loop force/torque control, task monitoring, and reflex action. This paper describes the STELER local-remote robot control system, and further describes the near-term planned Space Station applications, along with potential far-term applications such as telescience, autonomous docking, and Lunar/Mars rovers.

Superiorization with level control

NASA Astrophysics Data System (ADS)

Cegielski, Andrzej; Al-Musallam, Fadhel

2017-04-01

The convex feasibility problem is to find a common point of a finite family of closed convex subsets. In many applications one requires something more, namely finding a common point of closed convex subsets which minimizes a continuous convex function. The latter requirement leads to an application of the superiorization methodology which is actually settled between methods for convex feasibility problem and the convex constrained minimization. Inspired by the superiorization idea we introduce a method which sequentially applies a long-step algorithm for a sequence of convex feasibility problems; the method employs quasi-nonexpansive operators as well as subgradient projections with level control and does not require evaluation of the metric projection. We replace a perturbation of the iterations (applied in the superiorization methodology) by a perturbation of the current level in minimizing the objective function. We consider the method in the Euclidean space in order to guarantee the strong convergence, although the method is well defined in a Hilbert space.

Putting the Power of Configuration in the Hands of the Users

NASA Technical Reports Server (NTRS)

Al-Shihabi, Mary-Jo; Brown, Mark; Rigolini, Marianne

2011-01-01

Goal was to reduce the overall cost of human space flight while maintaining the most demanding standards for safety and mission success. In support of this goal, a project team was chartered to replace 18 legacy Space Shuttle nonconformance processes and systems with one fully integrated system Problem Reporting and Corrective Action (PRACA) processes provide a closed-loop system for the identification, disposition, resolution, closure, and reporting of all Space Shuttle hardware/software problems PRACA processes are integrated throughout the Space Shuttle organizational processes and are critical to assuring a safe and successful program Primary Project Objectives Develop a fully integrated system that provides an automated workflow with electronic signatures Support multiple NASA programs and contracts with a single "system" architecture Define standard processes, implement best practices, and minimize process variations

Microbial ecology of the closed artificial ecosystem MELiSSA (Micro-Ecological Life Support System Alternative): reinventing and compartmentalizing the Earth's food and oxygen regeneration system for long-haul space exploration missions.

PubMed

Hendrickx, Larissa; De Wever, Heleen; Hermans, Veronik; Mastroleo, Felice; Morin, Nicolas; Wilmotte, Annick; Janssen, Paul; Mergeay, Max

2006-01-01

MELiSSA is a bioregenerative life support system designed by the European Space Agency (ESA) for the complete recycling of gas, liquid and solid wastes during long distance space exploration. The system uses the combined activity of different living organisms: microbial cultures in bioreactors, a plant compartment and a human crew. In this minireview, the development of a short-cut ecological system for the biotransformation of organic waste is discussed from a microorganism's perspective. The artificial ecological model--still in full development--that is inspired by Earth's own geomicrobiological ecosystem serves as an ideal study object on microbial ecology and will become an indispensable travel companion in manned space exploration.

Photometric Data from Non-Resolved Objects for Space Object Characterization and Improved Atmospheric Modeling

NASA Astrophysics Data System (ADS)

Linares, R.; Palmer, D.; Thompson, D.; Koller, J.

2013-09-01

Recent events in space, including the collision of Russia's Cosmos 2251 satellite with Iridium 33 and China's Feng Yun 1C anti-satellite demonstration, have stressed the capabilities of Space Surveillance Network (SSN) and its ability to provide accurate and actionable impact probability estimates. The SSN network has the unique challenge of tracking more than 18,000 resident space objects (RSOs) and providing critical collision avoidance warnings to military, NASA, and commercial systems. However, due to the large number of RSOs and the limited number of sensors available to track them, it is impossible to maintain persistent surveillance. Observation gaps result in large propagation intervals between measurements and close approaches. Coupled with nonlinear RSO dynamics this results in difficulty in modeling the probability distribution functions (pdfs) of the RSO. In particular low-Earth orbiting (LEO) satellites are heavily influenced by atmospheric drag, which is very difficult to model accurately. A number of atmospheric models exist which can be classified as either empirical or physics-based models. The current Air Force standard is the High Accuracy Satellite Drag Model (HASDM), which is an empirical model based on observation of calibration satellites. These satellite observations are used to determine model parameters based on their orbit determination solutions. Atmospheric orbits are perturbed by a number of factors including drag coefficient, attitude, and shape of the space object. The satellites used for the HASDM model calibration process are chosen because of their relatively simple shapes, to minimize errors introduced due to shape miss-modeling. Under this requirement the number of calibration satellites that can be used for calibrating the atmospheric models is limited. Los Alamos National Laboratory (LANL) has established a research effort, called IMPACT (Integrated Modeling of Perturbations in Atmospheres for Conjunction Tracking), to improve impact assessment via improved physics-based modeling. As part of this effort calibration satellite observations are used to dynamically calibrate the physics-based model and to improve its forecasting capability. The observations are collected from a variety of sources, including from LANL's own Raven-class optical telescope. This system collects both astrometric and photometric data on space objects. The photometric data will be used to estimate the space objects' attitude and shape. Non-resolved photometric data have been studied by many as a mechanism for space object characterization. Photometry is the measurement of an object's flux or apparent brightness measured over a wavelength band. The temporal variation of photometric measurements is referred to as photometric signature. The photometric optical signature of an object contains information about shape, attitude, size and material composition. This work focuses on the processing of the data collected with LANL's telescope in an effort to use photometric data to expand the number of space objects that can be used as calibration satellites. An Unscented Kalman filter is used to estimate the attitude and angular velocity of the space object; both real data and simulated data scenarios are shown. A number of inactive space objects are used for the real data examples and good estimation results are shown.

Regional Differences in Tropical Lightning Distributions.

NASA Astrophysics Data System (ADS)

Boccippio, Dennis J.; Goodman, Steven J.; Heckman, Stan

2000-12-01

Observations from the National Aeronautics and Space Administration Optical Transient Detector (OTD) and Tropical Rainfall Measuring Mission (TRMM)-based Lightning Imaging Sensor (LIS) are analyzed for variability between land and ocean, various geographic regions, and different (objectively defined) convective `regimes.' The bulk of the order-of-magnitude differences between land and ocean regional flash rates are accounted for by differences in storm spacing (density) and/or frequency of occurrence, rather than differences in storm instantaneous flash rates, which only vary by a factor of 2 on average. Regional variability in cell density and cell flash rates closely tracks differences in 85-GHz microwave brightness temperatures. Monotonic relationships are found with the gross moist stability of the tropical atmosphere, a large-scale `adjusted state' parameter. This result strongly suggests that it will be possible, using TRMM observations, to objectively test numerical or theoretical predictions of how mesoscale convective organization interacts with the larger-scale environment. Further parameters are suggested for a complete objective definition of tropical convective regimes.

Hydraulically-activated operating system for an electric circuit breaker

DOEpatents

Imam, Imdad; Barkan, Philip

1979-01-01

This operating system comprises a fluid motor having a piston, a breaker-opening space at one side of the piston, and a breaker-closing space at its opposite side. An accumulator freely communicates with the breaker-opening space for supplying pressurized fluid thereto during a circuit-breaker opening operation. A normally-closed valve located on the breaker-closing-side of the piston is openable to release liquid from the breaker-closing space so that pressurized liquid in the breaker-opening space can drive the piston in an opening direction. Means is provided for restoring the valve to its closed position following the circuit-breaker opening operation. An impeded passage affords communication between the accumulator and the breaker-closing space to allow pressurized liquid to flow from the accumulator to the breaker-closing space and develop a pressure therein substantially equal to accumulator pressure when the valve is restored to closed position following breaker-opening. This passage is so impeded that the flow therethrough from the accumulator into the breaker-closing space is sufficiently low during initial opening motion of the piston through a substantial portion of its opening stroke as to avoid interference with said initial opening motion of the piston.

The MetaTelescope, a System for the Detection of Objects in Low and Higher Earth Orbits

NASA Astrophysics Data System (ADS)

Boer, M.

We present an original design involving several telescopes for the detection of mobiles in space over a very wide field of view. The system uses relatively simple and cheap telescopes associated with commercial CCD cameras that can be placed either in a single location or in relatively close (100m - 10km) locations. This last set-up opens the possibility of detecting parallaxes, but sky conditions should remain almost identical. Areas on the order of 800 square degrees can be surveyed. The system is versatile, i.e. it can detect and follow up objects either in the LEO or higher orbits. We will present the system, how it can be operated in order to have a more efficient setup while using even less telescopes, and possible implementations for space surveillance activities.

The Radar Roadmap

DTIC Science & Technology

2013-01-01

local oscillator to measure the phase of both the transmitted and received pulses and then matching them to the correct range ambiguity. 2.5 High...track closely spaced objects. White Sands Missile Range (WSMR) and Patrick Air Force Base (AFB) operate the phased -array AN/MPS-39 MOTRs. The...ABERDEEN TEST CENTER DUGWAY PROVING GROUND REAGAN TEST SITE YUMA PROVING GROUND WHITE SANDS MISSILE RANGE NAVAL AIR WARFARE CENTER AIRCRAFT

Profile fitting in crowded astronomical images

NASA Astrophysics Data System (ADS)

Manish, Raja

Around 18,000 known objects currently populate the near Earth space. These constitute active space assets as well as space debris objects. The tracking and cataloging of such objects relies on observations, most of which are ground based. Also, because of the great distance to the objects, only non-resolved object images can be obtained from the observations. Optical systems consist of telescope optics and a detector. Nowadays, usually CCD detectors are used. The information that is sought to be extracted from the frames are the individual object's astrometric position. In order to do so, the center of the object's image on the CCD frame has to be found. However, the observation frames that are read out of the detector are subject to noise. There are three different sources of noise: celestial background sources, the object signal itself and the sensor noise. The noise statistics are usually modeled as Gaussian or Poisson distributed or their combined distribution. In order to achieve a near real time processing, computationally fast and reliable methods for the so-called centroiding are desired; analytical methods are preferred over numerical ones of comparable accuracy. In this work, an analytic method for the centroiding is investigated and compared to numerical methods. Though the work focuses mainly on astronomical images, same principle could be applied on non-celestial images containing similar data. The method is based on minimizing weighted least squared (LS) error between observed data and the theoretical model of point sources in a novel yet simple way. Synthetic image frames have been simulated. The newly developed method is tested in both crowded and non-crowded fields where former needs additional image handling procedures to separate closely packed objects. Subsequent analysis on real celestial images corroborate the effectiveness of the approach.

The NICMOS Cooling SYSTEM-5 Years of Successful On-Orbit Operation

NASA Astrophysics Data System (ADS)

Swift, W. L.; Dolan, F. X.; Zagarola, M. V.

2008-03-01

The NICMOS Cooling System consists of a closed-loop turbo-Brayton cryocooler coupled with a cryogenic circulator that provides refrigeration to the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope (HST). The cryocooler heat is rejected to space through a capillary pumped loop connected to radiators mounted on the side of the telescope. The system was deployed and integrated with NICMOS by astronauts during STS-109 (Space Shuttle Columbia) in March 2002. It has operated nearly continuously without performance degradation since that time, maintaining NICMOS detectors at a constant temperature of 77 K. Miniature, high-speed turbomachines are used in the cryocooler and the circulator loop to provide vibration-free, long-life operation. A small centrifugal compressor and miniature turboalternator are key elements of the closed loop cryocooler. A miniature cryogenic centrifugal circulator in a separate pressurized neon loop transports heat from the NICMOS instrument to the cryocooler interface heat exchanger. This paper describes the development of the system, key operational features, ground and orbital tests prior to its deployment, and operational results during its five-year operational history on orbit.

Streak detection and analysis pipeline for space-debris optical images

NASA Astrophysics Data System (ADS)

Virtanen, Jenni; Poikonen, Jonne; Säntti, Tero; Komulainen, Tuomo; Torppa, Johanna; Granvik, Mikael; Muinonen, Karri; Pentikäinen, Hanna; Martikainen, Julia; Näränen, Jyri; Lehti, Jussi; Flohrer, Tim

2016-04-01

We describe a novel data-processing and analysis pipeline for optical observations of moving objects, either of natural (asteroids, meteors) or artificial origin (satellites, space debris). The monitoring of the space object populations requires reliable acquisition of observational data, to support the development and validation of population models and to build and maintain catalogues of orbital elements. The orbital catalogues are, in turn, needed for the assessment of close approaches (for asteroids, with the Earth; for satellites, with each other) and for the support of contingency situations or launches. For both types of populations, there is also increasing interest to detect fainter objects corresponding to the small end of the size distribution. The ESA-funded StreakDet (streak detection and astrometric reduction) activity has aimed at formulating and discussing suitable approaches for the detection and astrometric reduction of object trails, or streaks, in optical observations. Our two main focuses are objects in lower altitudes and space-based observations (i.e., high angular velocities), resulting in long (potentially curved) and faint streaks in the optical images. In particular, we concentrate on single-image (as compared to consecutive frames of the same field) and low-SNR detection of objects. Particular attention has been paid to the process of extraction of all necessary information from one image (segmentation), and subsequently, to efficient reduction of the extracted data (classification). We have developed an automated streak detection and processing pipeline and demonstrated its performance with an extensive database of semisynthetic images simulating streak observations both from ground-based and space-based observing platforms. The average processing time per image is about 13 s for a typical 2k-by-2k image. For long streaks (length >100 pixels), primary targets of the pipeline, the detection sensitivity (true positives) is about 90% for both scenarios for the bright streaks (SNR > 1), while in the low-SNR regime, the sensitivity is still 50% at SNR = 0.5 .

Exogenous temporal cues enhance recognition memory in an object-based manner.

PubMed

Ohyama, Junji; Watanabe, Katsumi

2010-11-01

Exogenous attention enhances the perception of attended items in both a space-based and an object-based manner. Exogenous attention also improves recognition memory for attended items in the space-based mode. However, it has not been examined whether object-based exogenous attention enhances recognition memory. To address this issue, we examined whether a sudden visual change in a task-irrelevant stimulus (an exogenous cue) would affect participants' recognition memory for items that were serially presented around a cued time. The results showed that recognition accuracy for an item was strongly enhanced when the visual cue occurred at the same location and time as the item (Experiments 1 and 2). The memory enhancement effect occurred when the exogenous visual cue and an item belonged to the same object (Experiments 3 and 4) and even when the cue was counterpredictive of the timing of an item to be asked about (Experiment 5). The present study suggests that an exogenous temporal cue automatically enhances the recognition accuracy for an item that is presented at close temporal proximity to the cue and that recognition memory enhancement occurs in an object-based manner.

76 FR 4412 - Commercial Space Transportation Advisory Committee-Closed Session

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-25

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... Commercial Space Transportation Advisory Committee Special Closed Session. SUMMARY: Pursuant to Section 10(a... Commercial Space Transportation Advisory Committee (COMSTAC). The special closed session will be an...

Comparing artistic and geometrical perspective depictions of space in the visual field

PubMed Central

Baldwin, Joseph; Burleigh, Alistair; Pepperell, Robert

2014-01-01

Which is the most accurate way to depict space in our visual field? Linear perspective, a form of geometrical perspective, has traditionally been regarded as the correct method of depicting visual space. But artists have often found it is limited in the angle of view it can depict; wide-angle scenes require uncomfortably close picture viewing distances or impractical degrees of enlargement to be seen properly. Other forms of geometrical perspective, such as fisheye projections, can represent wider views but typically produce pictures in which objects appear distorted. In this study we created an artistic rendering of a hemispherical visual space that encompassed the full visual field. We compared it to a number of geometrical perspective projections of the same space by asking participants to rate which best matched their visual experience. We found the artistic rendering performed significantly better than the geometrically generated projections. PMID:26034563

Comparing artistic and geometrical perspective depictions of space in the visual field.

PubMed

Baldwin, Joseph; Burleigh, Alistair; Pepperell, Robert

2014-01-01

Which is the most accurate way to depict space in our visual field? Linear perspective, a form of geometrical perspective, has traditionally been regarded as the correct method of depicting visual space. But artists have often found it is limited in the angle of view it can depict; wide-angle scenes require uncomfortably close picture viewing distances or impractical degrees of enlargement to be seen properly. Other forms of geometrical perspective, such as fisheye projections, can represent wider views but typically produce pictures in which objects appear distorted. In this study we created an artistic rendering of a hemispherical visual space that encompassed the full visual field. We compared it to a number of geometrical perspective projections of the same space by asking participants to rate which best matched their visual experience. We found the artistic rendering performed significantly better than the geometrically generated projections.

78 FR 70093 - Commercial Space Transportation Advisory Committee-Closed Session

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-22

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... Commercial Space Transportation Advisory Committee Special Closed Session. SUMMARY: Pursuant to Section 10(a...), notice is hereby given of a special closed session of the Commercial Space Transportation Advisory...

78 FR 53497 - Commercial Space Transportation Advisory Committee; Closed Session

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-29

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... Commercial Space Transportation Advisory Committee Special Closed Session. SUMMARY: Pursuant to Section 10(a...), notice is hereby given of a special closed session of the Commercial Space Transportation Advisory...

A Method of Classifying Tongue Colors for Traditional Chinese Medicine Diagnosis Based on the CIELAB Color Space

NASA Astrophysics Data System (ADS)

Li, Bocong; Huang, Qingmei; Lu, Yan; Chen, Songhe; Liang, Rong; Wang, Zhaoping

Objective tongue color analysis is an important research point for tongue diagnosis in Traditional Chinese Medicine. In this paper a research based on the clinical process of diagnosing tongue color is reported. The color data in RGB color space were first transformed into the data in CIELAB color space, and the color gamut of the displayed tongue was obtained. Then a numerical method of tongue color classification based on the Traditional Chinese Medicine (for example: light white tongue, light red tongue, red tongue) was developed. The conclusion is that this research can give the description and classification of the tongue color close to those given by human vision and may be carried out in clinical diagnosis.

Control technology development

NASA Astrophysics Data System (ADS)

Schaechter, D. B.

1982-03-01

The main objectives of the control technology development task are given in the slide below. The first is to develop control design techniques based on flexible structural models, rather than simple rigid-body models. Since large space structures are distributed parameter systems, a new degree of freedom, that of sensor/actuator placement, may be exercised for improving control system performance. Another characteristic of large space structures is numerous oscillatory modes within the control bandwidth. Reduced-order controller design models must be developed which produce stable closed-loop systems when combined with the full-order system. Since the date of an actual large-space-structure flight is rapidly approaching, it is vitally important that theoretical developments are tested in actual hardware. Experimental verification is a vital counterpart of all current theoretical developments.

Efficient Spatiotemporal Clutter Rejection and Nonlinear Filtering-based Dim Resolved and Unresolved Object Tracking Algorithms

NASA Astrophysics Data System (ADS)

Tartakovsky, A.; Tong, M.; Brown, A. P.; Agh, C.

2013-09-01

We develop efficient spatiotemporal image processing algorithms for rejection of non-stationary clutter and tracking of multiple dim objects using non-linear track-before-detect methods. For clutter suppression, we include an innovative image alignment (registration) algorithm. The images are assumed to contain elements of the same scene, but taken at different angles, from different locations, and at different times, with substantial clutter non-stationarity. These challenges are typical for space-based and surface-based IR/EO moving sensors, e.g., highly elliptical orbit or low earth orbit scenarios. The algorithm assumes that the images are related via a planar homography, also known as the projective transformation. The parameters are estimated in an iterative manner, at each step adjusting the parameter vector so as to achieve improved alignment of the images. Operating in the parameter space rather than in the coordinate space is a new idea, which makes the algorithm more robust with respect to noise as well as to large inter-frame disturbances, while operating at real-time rates. For dim object tracking, we include new advancements to a particle non-linear filtering-based track-before-detect (TrbD) algorithm. The new TrbD algorithm includes both real-time full image search for resolved objects not yet in track and joint super-resolution and tracking of individual objects in closely spaced object (CSO) clusters. The real-time full image search provides near-optimal detection and tracking of multiple extremely dim, maneuvering objects/clusters. The super-resolution and tracking CSO TrbD algorithm provides efficient near-optimal estimation of the number of unresolved objects in a CSO cluster, as well as the locations, velocities, accelerations, and intensities of the individual objects. We demonstrate that the algorithm is able to accurately estimate the number of CSO objects and their locations when the initial uncertainty on the number of objects is large. We demonstrate performance of the TrbD algorithm both for satellite-based and surface-based EO/IR surveillance scenarios.

Your place or mine: shared sensory experiences elicit a remapping of peripersonal space.

PubMed

Maister, Lara; Cardini, Flavia; Zamariola, Giorgia; Serino, Andrea; Tsakiris, Manos

2015-04-01

Our perceptual systems integrate multisensory information about objects that are close to our bodies, which allow us to respond quickly and appropriately to potential threats, as well as act upon and manipulate useful tools. Intriguingly, the representation of this area close to our body, known as the multisensory 'peripersonal space' (PPS), can expand or contract during social interactions. However, it is not yet known how different social interactions can alter the representation of PPS. In particular, shared sensory experiences, such as those elicited by bodily illusions such as the enfacement illusion, can induce feelings of ownership over the other's body which has also been shown to increase the remapping of the other's sensory experiences onto our own bodies. The current study investigated whether such shared sensory experiences between two people induced by the enfacement illusion could alter the way PPS was represented, and whether this alteration could be best described as an expansion of one's own PPS towards the other or a remapping of the other's PPS onto one's own. An audio-tactile integration task allowed us to measure the extent of the PPS before and after a shared sensory experience with a confederate. Our results showed a clear increase in audio-tactile integration in the space close to the confederate's body after the shared experience. Importantly, this increase did not extend across the space between participant and confederate, as would be expected if the participant's PPS had expanded. Thus, the pattern of results is more consistent with a partial remapping of the confederate's PPS onto the participant's own PPS. These results have important consequences for our understanding of interpersonal space during different kinds of social interactions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Summer High School Apprenticeship Research Program (SHARP) of the National Aeronautics and Space Administration

NASA Technical Reports Server (NTRS)

1984-01-01

A total of 125 talented high school students had the opportunity to gain first hand experience about science and engineering careers by working directly with a NASA scientist or engineer during the summer. This marked the fifth year of operation for NASA's Summer High School Apprenticehsip Research Program (SHARP). Ferguson Bryan served as the SHARP contractor and worked closely with NASA staff at Headquarters and the eight participating sites to plan, implement, and evaluate the Program. The main objectives were to strengthen SHARP and expand the number of students in the Program. These eight sites participated in the Program: Ames Research Center North, Ames' Dryden Flight Research Facility, Goddard Space Flight Center, Goddard's Wallops Flight Facility, Kennedy Space Center, Langley Research Center, Lewis Research Center, and Marshall Space Flight Center.

Classification and pose estimation of objects using nonlinear features

NASA Astrophysics Data System (ADS)

Talukder, Ashit; Casasent, David P.

1998-03-01

A new nonlinear feature extraction method called the maximum representation and discrimination feature (MRDF) method is presented for extraction of features from input image data. It implements transformations similar to the Sigma-Pi neural network. However, the weights of the MRDF are obtained in closed form, and offer advantages compared to nonlinear neural network implementations. The features extracted are useful for both object discrimination (classification) and object representation (pose estimation). We show its use in estimating the class and pose of images of real objects and rendered solid CAD models of machine parts from single views using a feature-space trajectory (FST) neural network classifier. We show more accurate classification and pose estimation results than are achieved by standard principal component analysis (PCA) and Fukunaga-Koontz (FK) feature extraction methods.

Position and force control of coordinated multiple arms

NASA Technical Reports Server (NTRS)

Hayati, Samad A.

1988-01-01

A technique is presented for controlling multiple manipulators which are holding a single object and therefore form a closed kinematic chain. The object, which may or may not be in contact with a rigid environment, is assumed to be held rigidly by n robot end-effectors. The derivation is based on setting up constraint equations which reduce the 6 x n degrees of freedom of n manipulators each having six joints. Additional constraint equations are considered when one or more degrees of freedom of the object are reduced due to external constraints. Utilizing the operational space dynamic equations, a decoupling controller is designed to control both the position and the interaction forces of the object with the environment. Simulation results for the control of a pair of two-link manipulators are presented.

Assessing Space Exploration Technology Requirements as a First Step Towards Ensuring Technology Readiness for International Cooperation in Space Exploration

NASA Technical Reports Server (NTRS)

Laurini, Kathleen C.; Hufenbach, Bernhard; Satoh, Maoki; Piedboeuf, Jean-Claude; Neumann, Benjamin

2010-01-01

Advancing critical and enhancing technologies is considered essential to enabling sustainable and affordable human space exploration. Critical technologies are those that enable a certain class of mission, such as technologies necessary for safe landing on the Martian surface, advanced propulsion, and closed loop life support. Others enhance the mission by leading to a greater satisfaction of mission objectives or increased probability of mission success. Advanced technologies are needed to reduce mass and cost. Many space agencies have studied exploration mission architectures and scenarios with the resulting lists of critical and enhancing technologies being very similar. With this in mind, and with the recognition that human space exploration will only be enabled by agencies working together to address these challenges, interested agencies participating in the International Space Exploration Coordination Group (ISECG) have agreed to perform a technology assessment as an important step in exploring cooperation opportunities for future exploration mission scenarios. "The Global Exploration Strategy: The Framework for Coordination" was developed by fourteen space agencies and released in May 2007. Since the fall of 2008, several International Space Exploration Coordination Group (ISECG) participating space agencies have been studying concepts for human exploration of the moon. They have identified technologies considered critical and enhancing of sustainable space exploration. Technologies such as in-situ resource utilization, advanced power generation/energy storage systems, reliable dust resistant mobility systems, and closed loop life support systems are important examples. Similarly, agencies such as NASA, ESA, and Russia have studied Mars exploration missions and identified critical technologies. They recognize that human and robotic precursor missions to destinations such as LEO, moon, and near earth objects provide opportunities to demonstrate the technologies needed for Mars mission. Agencies see the importance of assessing gaps and overlaps in their plans to advance technologies in order to leverage their investments and enable exciting missions as soon as practical. They see the importance of respecting the ability of any agency to invest in any technologies considered interesting or strategic. This paper will describe the importance of developing an appropriate international strategy for technology development and ideas for effective mechanisms for advancing an international strategy. This work will both inform and be informed by the development of an ISECG Global Exploration Roadmap and serve as a concrete step forward in advancing the Global Exploration Strategy.

Lunar stepping stones to a manned Mars exploration scenario

NASA Technical Reports Server (NTRS)

Davidson, W. L.; Stump, W. R.

1992-01-01

The initial trips to Mars by humans will be the first real severing of our dependence on Earth's environment. Common sense dictates that a human departure from Earth measured in years, to explore a distant planet, requires systems, techniques, and operations that have solid credibility proven with space experience. The space test and verification experience must occur with Mars-like conditions but under proving-ground conditions with good instrumentation, close monitoring, and fast emergency recovery capabilities. The lunar environment is the only arena that satisfies the requirements of a space recovery capabilities. The lunar environment is the only arena that satisfies the requirements of a space planetary proving-ground. The objective of this scenario is to demonstrate a program planning approach that has human presence at Mars as the goal but, prudently, capitalizes on manned lunar project facilities, operations, and experience to enable a safe journey for the first Mars crews. The emphasis in lunar application objectives is to perform productive science and resources exploitation missions. Most of the Mars mission aspects can be proven in the lunar environment providing 'stepping stones' to conducting the first human mission to travel to Mars and return safely to Earth.

Launch COLA Gap Analysis for Protection of the International Space Station

NASA Astrophysics Data System (ADS)

Jenkin, Alan B.; McVey, John P.; Peterson, Glenn E.; Sorge, Marlon E.

2013-08-01

For launch missions in general, a collision avoidance (COLA) gap exists between the end of the time interval covered by standard launch COLA screening and the time that other spacecraft can clear a collision with the newly launched objects. To address this issue for the International Space Station (ISS), a COLA gap analysis process has been developed. The first part of the process, nodal separation analysis, identifies launch dates and launch window opportunities when the orbit traces of a launched object and the ISS could cross during the COLA gap. The second and newest part of the analysis process, Monte Carlo conjunction probability analysis, is performed closer to the launch dates of concern to reopen some of the launch window opportunities that would be closed by nodal separation analysis alone. Both parts of the process are described and demonstrated on sample missions.

Microshutter Array Development for the Multi-Object Spectrograph for the New Generation Space Telescope, and Its Ground-based Demonstrator

NASA Technical Reports Server (NTRS)

Woodgate, Bruce E.; Moseley, Harvey; Fettig, Rainer; Kutyrev, Alexander; Ge, Jian; Fisher, Richard R. (Technical Monitor)

2001-01-01

The 6.5-m NASA/ESA/Canada New Generation Space Telescope to be operated at the L2 Lagrangian point will require a multi-object spectrograph (MOS) operating from 1 to 5 microns. Up to 3000 targets will be selected for simultaneous spectroscopy using a programmable cryogenic (approx. 35K) aperture array, consisting of a mosaic of arrays of micromirrors or microshutters. We describe the current status of the GSFC microshutter array development. The 100 micron square shutters are opened magnetically and latched open or closed electrostatically. Selection will be by two crossed one-dimensional addressing circuits. We will demonstrate the use of a 512 x 512 unit array on a ground-based IR MOS which will cover 0.6 to 5 microns, and operate rapidly to include spectroscopy of gamma ray burst afterglows.

Launch Collision Probability

NASA Technical Reports Server (NTRS)

Bollenbacher, Gary; Guptill, James D.

1999-01-01

This report analyzes the probability of a launch vehicle colliding with one of the nearly 10,000 tracked objects orbiting the Earth, given that an object on a near-collision course with the launch vehicle has been identified. Knowledge of the probability of collision throughout the launch window can be used to avoid launching at times when the probability of collision is unacceptably high. The analysis in this report assumes that the positions of the orbiting objects and the launch vehicle can be predicted as a function of time and therefore that any tracked object which comes close to the launch vehicle can be identified. The analysis further assumes that the position uncertainty of the launch vehicle and the approaching space object can be described with position covariance matrices. With these and some additional simplifying assumptions, a closed-form solution is developed using two approaches. The solution shows that the probability of collision is a function of position uncertainties, the size of the two potentially colliding objects, and the nominal separation distance at the point of closest approach. ne impact of the simplifying assumptions on the accuracy of the final result is assessed and the application of the results to the Cassini mission, launched in October 1997, is described. Other factors that affect the probability of collision are also discussed. Finally, the report offers alternative approaches that can be used to evaluate the probability of collision.

Supersymmetrizing the Gorsky-Shifman-Yung soliton

NASA Astrophysics Data System (ADS)

Ireson, E.; Shifman, M.; Yung, A.

2018-05-01

We supersymmetrize the Hopfion studied by Gorsky et al. [Phys. Rev. D 88, 045026 (2013)., 10.1103/PhysRevD.88.045026]. This soliton represents a closed semilocal vortex string in U(1) gauge theory. It carries nonzero Hopf number due to the additional winding of a phase modulus as one moves along the closed string. We study this solution in N =2 supersymmetric QED with two flavors. As a preliminary exercise, we compactify one space dimension and consider a straight vortex with periodic boundary conditions. It turns out to be 1 /2 -BPS saturated. An additional winding along the string can be introduced and it does not spoil the BPS nature of the object. Next, we consider a ringlike vortex in a non-compact space and show that the circumference of the ring L can be stabilized once the previously mentioned winding along the string is introduced. Of course, the ringlike vortex is not BPS but its energy becomes close to the BPS bound if L is large, which can be guaranteed in the case that we have a large value of the angular momentum J . Thus we arrive at the concept of asymptotically BPS-saturated solitons. BPS saturation is achieved in the limit J →∞ .

Hydraulic actuator for an electric circuit breaker

DOEpatents

Imam, I.

1983-05-17

This actuator comprises a fluid motor having a piston, a breaker-opening space at one side of the piston, and a breaker-closing space at its opposite side. An accumulator freely communicates with the breaker-opening space for supplying pressurized fluid thereto during a circuit breaker opening operation. The breaker-opening space and the breaker-closing space are connected by an impeded flow passage. A pilot valve opens to allow the pressurized liquid in the breaker-closing space to flow to a back chamber of a normally closed main valve to cause the main valve to be opened during a circuit breaker opening operation to release the pressurized liquid from the breaker-closing space. An impeded passage affords communication between the back chamber and a sump located on the opposite side of the main valve from the back chamber. The pilot valve and impeded passage allow rapid opening of the main valve with pressurized liquid from the breaker closing side of the piston. 3 figs.

Hydraulic actuator for an electric circuit breaker

DOEpatents

Imam, Imdad [Colonie, NY

1983-01-01

This actuator comprises a fluid motor having a piston, a breaker-opening space at one side of the piston, and a breaker-closing space at its opposite side. An accumulator freely communicates with the breaker-opening space for supplying pressurized fluid thereto during a circuit breaker opening operation. The breaker-opening space and the breaker-closing space are connected by an impeded flow passage. A pilot valve opens to allow the pressurized liquid in the breaker-closing space to flow to a back chamber of a normally closed main valve to cause the main valve to be opened during a circuit breaker opening operation to release the pressurized liquid from the breaker-closing space. An impeded passage affords communication between the back chamber and a sump located on the opposite side of the main valve from the back chamber. The pilot valve and impeded passage allow rapid opening of the main valve with pressurized liquid from the breaker closing side of the piston.

Testing and Comparative Evaluation of Space Shuttle Main Engine Flowmeter Bearings

NASA Technical Reports Server (NTRS)

Hissam, Andy; Leberman, Mike; McLeroy, Rick

2005-01-01

This paper provides a summary of testing of Space Shuttle Main Engine (SSME) flowmeter bearings and cage material. These tests were con&cM over a several month period in 2004 at the Marshall Space Flight Center. The test program's primary objective was to compare the performance of bearings using the existing cage material and bearings using a proposed replacement cage material. In order to meet the test objectives for this program, a flowmeter test rig was designed and fabricated to measure both breakaway and running torque for a flowmeter assembly. Other test parameters,,such as motor current and shaft speed, were also recorded and provide a means of comparing bearing performance. The flowmeter and bearings were tested in liquid hydrogen to simulate the flowmeter's operating environment as closely as possible. Based on the results from this testing, the bearings with the existing cage material are equivalent to the bearings with the proposed replacement cage material. No major differences exist between the old and new cage materials. Therefore, the new cage material is a suitable replacement for the existing cage material.

Characterization of Inactive Rocket Bodies Via Non-Resolved Photometric Data

NASA Astrophysics Data System (ADS)

Linares, R.; Palmer, D.; Thompson, D.; Klimenko, A.

2014-09-01

Recent events in space, including the collision of Russias Cosmos 2251 satellite with Iridium 33 and Chinas Feng Yun 1C anti-satellite demonstration, have stressed the capabilities of Space Surveillance Network (SSN) and its ability to provide accurate and actionable impact probability estimates. The SSN network has the unique challenge of tracking more than 18,000 resident space objects (RSOs) and providing critical collision avoidance warnings to military, NASA, and commercial systems. However, due to the large number of RSOs and the limited number of sensors available to track them, it is impossible to maintain persistent surveillance. Observation gaps result in large propagation intervals between measurements and close approaches. Coupled with nonlinear RSO dynamics this results in difficulty in modeling the probability distribution functions (pdfs) of the RSO. In particular low-Earth orbiting (LEO) satellites are heavily influenced by atmospheric drag, which is very difficult to model accurately. A number of atmospheric models exist which can be classified as either empirical or physics-based models. The current Air Force standard is the High Accuracy Satellite Drag Model (HASDM), which is an empirical model based on observation of calibration satellites. These satellite observations are used to determine model parameters based on their orbit determination solutions. Atmospheric orbits are perturbed by a number of factors including drag coefficient, attitude, and shape of the space object. The satellites used for the HASDM model calibration process are chosen because of their relatively simple shapes, to minimize errors introduced due to shape miss-modeling. Under this requirement the number of calibration satellites that can be used for calibrating the atmospheric models is limited. Los Alamos National Laboratory (LANL) has established a research effort, called IMPACT (Integrated Modeling of Perturbations in Atmospheres for Conjunction Tracking), to improve impact assessment via improved physics-based modeling. As part of this effort calibration satellite observations are used to dynamically calibrate the physics-based model and to improve its forecasting capability. The observations are collected from a variety of sources, including from LANLs own Raven-class optical telescope. This system collects both astrometric and photometric data on space objects. The photometric data will be used to estimate the space objects attitude and shape. Non-resolved photometric data have been studied by many as a mechanism for space object characterization. Photometry is the measurement of an objects flux or apparent brightness measured over a wavelength band. The temporal variation of photometric measurements is referred to as photometric signature. The photometric optical signature of an object contains information about shape, attitude, size and material composition. This work focuses on the processing of the data collected with LANLs telescope in an effort to use photometric data to expand the number of space objects that can be used as calibration satellites. A nonlinear least squares is used to estimate the attitude and angular velocity of the space object; a number of real data examples are shown. Inactive space objects are used for the real data examples and good estimation results are shown.

Optimization algorithms for large-scale multireservoir hydropower systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hiew, K.L.

Five optimization algorithms were vigorously evaluated based on applications on a hypothetical five-reservoir hydropower system. These algorithms are incremental dynamic programming (IDP), successive linear programing (SLP), feasible direction method (FDM), optimal control theory (OCT) and objective-space dynamic programming (OSDP). The performance of these algorithms were comparatively evaluated using unbiased, objective criteria which include accuracy of results, rate of convergence, smoothness of resulting storage and release trajectories, computer time and memory requirements, robustness and other pertinent secondary considerations. Results have shown that all the algorithms, with the exception of OSDP converge to optimum objective values within 1.0% difference from one another.more » The highest objective value is obtained by IDP, followed closely by OCT. Computer time required by these algorithms, however, differ by more than two orders of magnitude, ranging from 10 seconds in the case of OCT to a maximum of about 2000 seconds for IDP. With a well-designed penalty scheme to deal with state-space constraints, OCT proves to be the most-efficient algorithm based on its overall performance. SLP, FDM, and OCT were applied to the case study of Mahaweli project, a ten-powerplant system in Sri Lanka.« less

Migration of Trans-Neptunian Objects to a Near-Earth Space

NASA Technical Reports Server (NTRS)

Ipatov, S. I.; Mather, J. C.; Oegerle, William (Technical Monitor)

2002-01-01

Our estimates of the migration of trans-Neptunian objects (TNOs) to a near-Earth space are based on the results of investigations of orbital evolution of TNOs and Jupiter-crossing objects (JCOs). The orbital evolution of TNOs was considered in many papers. Recently we investigated the evolution for intervals of at least 5-10 Myr of 2500 JCOs under the gravitational influence of all planets, except for Mercury and Pluto (without dissipative factors). In the first series we considered N=2000 orbits near the orbits of 30 real Jupiter-family comets with period P(sub alpha)less than 10 yr, and in the second series we took N=500 orbits close to the orbit of Comet 10P Tempel 2 (alpha=3.1 AU, e=0.53, i=12 deg). We calculated the probabilities of collisions of objects with the terrestrial planets, using orbital elements obtained with a step equal to 500 yr, and then summarized the results for all time intervals and all bodies, obtaining the total probability P(sub sigma) of collisions with a planet and the total time interval T(sub sigma) during which perihelion distance q of bodies was less than a semimajor axis of the planet.

On Efficient Deployment of Wireless Sensors for Coverage and Connectivity in Constrained 3D Space.

PubMed

Wu, Chase Q; Wang, Li

2017-10-10

Sensor networks have been used in a rapidly increasing number of applications in many fields. This work generalizes a sensor deployment problem to place a minimum set of wireless sensors at candidate locations in constrained 3D space to k -cover a given set of target objects. By exhausting the combinations of discreteness/continuousness constraints on either sensor locations or target objects, we formulate four classes of sensor deployment problems in 3D space: deploy sensors at Discrete/Continuous Locations (D/CL) to cover Discrete/Continuous Targets (D/CT). We begin with the design of an approximate algorithm for DLDT and then reduce DLCT, CLDT, and CLCT to DLDT by discretizing continuous sensor locations or target objects into a set of divisions without sacrificing sensing precision. Furthermore, we consider a connected version of each problem where the deployed sensors must form a connected network, and design an approximation algorithm to minimize the number of deployed sensors with connectivity guarantee. For performance comparison, we design and implement an optimal solution and a genetic algorithm (GA)-based approach. Extensive simulation results show that the proposed deployment algorithms consistently outperform the GA-based heuristic and achieve a close-to-optimal performance in small-scale problem instances and a significantly superior overall performance than the theoretical upper bound.

NASA/MSFC ground experiment for large space structure control verification

NASA Technical Reports Server (NTRS)

Waites, H. B.; Seltzer, S. M.; Tollison, D. K.

1984-01-01

Marshall Space Flight Center has developed a facility in which closed loop control of Large Space Structures (LSS) can be demonstrated and verified. The main objective of the facility is to verify LSS control system techniques so that on orbit performance can be ensured. The facility consists of an LSS test article which is connected to a payload mounting system that provides control torque commands. It is attached to a base excitation system which will simulate disturbances most likely to occur for Orbiter and DOD payloads. A control computer will contain the calibration software, the reference system, the alignment procedures, the telemetry software, and the control algorithms. The total system will be suspended in such a fashion that LSS test article has the characteristics common to all LSS.

The Next Giant Leap: Human Exploration and Utilization of NEOs

NASA Astrophysics Data System (ADS)

Jones, T. D.; Vilas, F.; Love, S.; Hack, K.; Gefert, L.; Sykes, M. V.; Lewis, J. S.; Jedicke, R.; Davis, D.; Hartmann, W. K.; Farquhar, R.; McFadden, L.; Durda, D.

2001-11-01

Planetary science plays a unique role as the pathfinder for future human space activities beyond the International Space Station. It can also provide the rationale for the first human departure from LEO since the Apollo program. We are examining the potential for human missions to small near-Earth objects (typically tens of meters), passing close by the Earth-Moon system with very low delta-v. A preliminary estimate suggests there may be many thousands of these objects, raising the possibility of number of launch opportunities each year. To demonstrate feasibility, we have simulated a mission to 1991 VG during 1991/1992 when it passed within 0.004 AU of the Earth. This mission takes a total of 60 days, including a 30 day stay time at the asteroid. The accessibility of these targets may provide an opportunity to develop and test systems needed for longer duration interplanetary missions to Mars, and to engage in precursor space resource utilization activities. Early discovery, orbit determination, and target characterization should be pursued and spacebased and groundbased systems that would be needed assessed. Crewed missions would be preceded by robotic probes to test acquisition, rendezvous, and local operations while returning significant new science from target objects. As we look beyond ISS over the next decade, we must reinvigorate a mutually supportive relationship between our human space and solar system exploration goals. The scientific and exploration rationale for sending humans to NEOs must be mature to meet NASA's decision making window, now opening, for operations beyond near-Earth space.

Overcoming the Subject-Object Dichotomy in Urban Modeling: Axial Maps as Geometric Representations of Affordances in the Built Environment.

PubMed

Marcus, Lars

2018-01-01

The world is witnessing unprecedented urbanization, bringing extreme challenges to contemporary practices in urban planning and design. This calls for improved urban models that can generate new knowledge and enhance practical skill. Importantly, any urban model embodies a conception of the relation between humans and the physical environment. In urban modeling this is typically conceived of as a relation between human subjects and an environmental object, thereby reproducing a humans-environment dichotomy. Alternative modeling traditions, such as space syntax that originates in architecture rather than geography, have tried to overcome this dichotomy. Central in this effort is the development of new representations of urban space, such as in the case of space syntax, the axial map. This form of representation aims to integrate both human behavior and the physical environment into one and the same description. Interestingly, models based on these representations have proved to better capture pedestrian movement than regular models. Pedestrian movement, as well as other kinds of human flows in urban space, is essential for urban modeling, since increasingly flows of this kind are understood as the driver in urban processes. Critical for a full understanding of space syntax modeling is the ontology of its' representations, such as the axial map. Space syntax theory here often refers to James Gibson's "Theory of affordances," where the concept of affordances, in a manner similar to axial maps, aims to bridge the subject-object dichotomy by neither constituting physical properties of the environment or human behavior, but rather what emerges in the meeting between the two. In extension of this, the axial map can be interpreted as a representation of how the physical form of the environment affords human accessibility and visibility in urban space. This paper presents a close examination of the form of representations developed in space syntax methodology, in particular in the light of Gibson's "theory of affordances." The overarching aim is to contribute to a theoretical framework for urban models based on affordances, which may support the overcoming of the subject-object dichotomy in such models, here deemed essential for a greater social-ecological sustainability of cities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoehn, A.; Chamberlain, D.J.; Forsyth, S.W.

PGBA, a plant growth facility developed for space flight biotechnology research, successfully grew a total of 30 plants in a closed, multi-crop chamber for 10 days aboard the Space Shuttle Endeavor (STS-77). {ital Artemisia annua, Catharanthus roseus, Pinus taeda, Spinacia oleracea and Trifolium repens} were the five species studied during this mission. The primary mission objectives were to study the effects of microgravity for commercial and pharmaceutical production purposes. PGBA is a payload that represents a consortium of interests including BioServe Space Technologies (payload sponsor), NASA Ames Research Center (Controlled Ecological Life Support System, CELSS, Flight Program), Wisconsin Center formore » Space Automation and Robotics (WCSAR), and industrial affiliates (spaceflight effects on plants and formation of plant products such as pharmaceuticals). Although BioServe is responsible for the flight hardware development and integration of PGBA, NASA Ames, WSCAR and industrial affiliates provide significant hardware subsystems and technical biological expertise support. {copyright} {ital 1997 American Institute of Physics.}« less

Updates to the NASA Space Telecommunications Radio System (STRS) Architecture

NASA Technical Reports Server (NTRS)

Kacpura, Thomas J.; Handler, Louis M.; Briones, Janette; Hall, Charles S.

2008-01-01

This paper describes an update of the Space Telecommunications Radio System (STRS) open architecture for NASA space based radios. The STRS architecture has been defined as a framework for the design, development, operation and upgrade of space based software defined radios, where processing resources are constrained. The architecture has been updated based upon reviews by NASA missions, radio providers, and component vendors. The STRS Standard prescribes the architectural relationship between the software elements used in software execution and defines the Application Programmer Interface (API) between the operating environment and the waveform application. Modeling tools have been adopted to present the architecture. The paper will present a description of the updated API, configuration files, and constraints. Minimum compliance is discussed for early implementations. The paper then closes with a summary of the changes made and discussion of the relevant alignment with the Object Management Group (OMG) SWRadio specification, and enhancements to the specialized signal processing abstraction.

Controlling the motion of a spacecraft when approaching a large object of space debris

NASA Astrophysics Data System (ADS)

Baranov, A. A.; Budyanskiy, A. A.; Razumnyi, Yu. N.

2017-07-01

The problem of calculating the parameters of maneuvering a spacecraft as it approaches a large object of space debris (LOSD) in close near-circular noncoplanar orbits has been considered. In [1-4], the results of analyzing the problem of the flyby of the separated LOSD groups have been presented. It has been assumed that a collector spacecraft approaches the LOSD and captures it or it is inserted into the nozzle of a small spacecraft that has a proper propulsion system (PS). However, in these papers, the flight from one object to another was only analyzed and the problem of approaching to LOSD with a given accuracy was not considered. This paper is a supplement to the cycle of papers [1-4]. It is assumed that, the final stage of approaching the LOSD is implemented by maneuvering in many orbits (up to several dozens) with low-thrust engines, but the PS operating time is fairly small compared with the orbit period in order to make it possible to use impulse approximation in the calculations.

Implementation of an Open-Scenario, Long-Term Space Debris Simulation Approach

NASA Technical Reports Server (NTRS)

Nelson, Bron; Yang Yang, Fan; Carlino, Roberto; Dono Perez, Andres; Faber, Nicolas; Henze, Chris; Karacalioglu, Arif Goktug; O'Toole, Conor; Swenson, Jason; Stupl, Jan

2015-01-01

This paper provides a status update on the implementation of a flexible, long-term space debris simulation approach. The motivation is to build a tool that can assess the long-term impact of various options for debris-remediation, including the LightForce space debris collision avoidance concept that diverts objects using photon pressure [9]. State-of-the-art simulation approaches that assess the long-term development of the debris environment use either completely statistical approaches, or they rely on large time steps on the order of several days if they simulate the positions of single objects over time. They cannot be easily adapted to investigate the impact of specific collision avoidance schemes or de-orbit schemes, because the efficiency of a collision avoidance maneuver can depend on various input parameters, including ground station positions and orbital and physical parameters of the objects involved in close encounters (conjunctions). Furthermore, maneuvers take place on timescales much smaller than days. For example, LightForce only changes the orbit of a certain object (aiming to reduce the probability of collision), but it does not remove entire objects or groups of objects. In the same sense, it is also not straightforward to compare specific de-orbit methods in regard to potential collision risks during a de-orbit maneuver. To gain flexibility in assessing interactions with objects, we implement a simulation that includes every tracked space object in Low Earth Orbit (LEO) and propagates all objects with high precision and variable time-steps as small as one second. It allows the assessment of the (potential) impact of physical or orbital changes to any object. The final goal is to employ a Monte Carlo approach to assess the debris evolution during the simulation time-frame of 100 years and to compare a baseline scenario to debris remediation scenarios or other scenarios of interest. To populate the initial simulation, we use the entire space-track object catalog in LEO. We then use a high precision propagator to propagate all objects over the entire simulation duration. If collisions are detected, the appropriate number of debris objects are created and inserted into the simulation framework. Depending on the scenario, further objects, e.g. due to new launches, can be added. At the end of the simulation, the total number of objects above a cut-off size and the number of detected collisions provide benchmark parameters for the comparison between scenarios. The simulation approach is computationally intensive as it involves tens of thousands of objects; hence we use a highly parallel approach employing up to a thousand cores on the NASA Pleiades supercomputer for a single run. This paper describes our simulation approach, the status of its implementation, the approach to developing scenarios and examples of first test runs.

46 CFR 92.15-10 - Ventilation for closed spaces.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Ventilation for closed spaces. 92.15-10 Section 92.15-10... CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except as noted in paragraph (c) of this section, all enclosed spaces within the vessel shall be properly vented or ventilated...

46 CFR 92.15-10 - Ventilation for closed spaces.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Ventilation for closed spaces. 92.15-10 Section 92.15-10... CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except as noted in paragraph (c) of this section, all enclosed spaces within the vessel shall be properly vented or ventilated...

46 CFR 92.15-10 - Ventilation for closed spaces.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Ventilation for closed spaces. 92.15-10 Section 92.15-10... CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except as noted in paragraph (c) of this section, all enclosed spaces within the vessel shall be properly vented or ventilated...

46 CFR 92.15-10 - Ventilation for closed spaces.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Ventilation for closed spaces. 92.15-10 Section 92.15-10... CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except as noted in paragraph (c) of this section, all enclosed spaces within the vessel shall be properly vented or ventilated...

46 CFR 92.15-10 - Ventilation for closed spaces.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Ventilation for closed spaces. 92.15-10 Section 92.15-10... CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except as noted in paragraph (c) of this section, all enclosed spaces within the vessel shall be properly vented or ventilated...

F.I.D.O. Focused Integration for Debris Observation

NASA Astrophysics Data System (ADS)

Ploschnitznig, J.

2013-09-01

The fact that satellites play a growing role in our day-to-day live, contributes to the overall assessment that these assets must be protected. As more and more objects enter space and begin to clutter this apparently endless vacuum, we begin to realize that these objects and associated debris become a potential and recurring threat. The space surveillance community routinely attempts to catalog debris through broad area search collection profiles, hoping to detect and track smaller and smaller objects. There are technical limitations to each collection system, we propose there may be new ways to increase the detection capability, effectively "Teaching an old dog (FIDO), new tricks." Far too often, we are justly criticized for never "stepping out of the box". The philosophy of "if it's not broke, don't fix it" works great if you assume that we are not broke. The assumption that in order to "Find" new space junk we need to increase our surveillance windows and try to cover as much space as possible may be appropriate for Missile Defense, but inappropriate for finding small space debris. Currently, our Phased Array Early Warning Systems support this yearly search program to try to acquire and track space small debris. A phased array can electronically scan the horizons very quickly, but the radar does have limitations. There is a closed-loop resource management equation that must be satisfied. By increasing search volume, we effectively reduce our instantaneous sensitivity which will directly impact our ability to find smaller and smaller space debris. Our proposal will be to focus on increasing sensitivity by reducing the search volume to statistically high probability of detection volumes in space. There are two phases to this proposal, a theoretical and empirical. Theoretical: The first phase will be to investigate the current space catalog and use existing ephemeris data on all satellites in the Space Surveillance Catalog to identify volumes of space with a high likelihood of encountering transiting satellite. Also during this phase, candidate radar systems will be characterized to determine sensitivity levels necessary to detect certain sized objects. Data integration plays a critical role in lowering the noise floor of the collection area in order to detect smaller and smaller objects. Reducing the search volume to these high probability of intercept areas will allow the use of data integration to increase the likelihood of detection of small Radar Cross Section objects. Empirical: The next phase is to employ this technique using a legacy collection system. The collection community may choose any collection system. The goal will be to demonstrate how focusing on a very specific area and employing data integration will increase the likelihood of detection of smaller objects. This will result in the creation of an Inter Range Vector (IRV), which can be handed-off to downrange collection systems for additional tracking. The goal of FIDO will be demonstrate how these legacy systems can be better employed to help find smaller and smaller debris.

Higher Plants in Space for MELiSSA -Literature Review and Future Directions

NASA Astrophysics Data System (ADS)

Zabrodina, Marina; Kittang, Ann-Iren; Coelho, Liz Helena; Karoliussen, Irene; Aase Wolff, Silje; Iversen, Tor-Henning

The human exploration of space requires the development of closed life support systems to regenerate oxygen, purify water, and produce food. MELiSSA (Micro-Ecological Life Support System Alternative) is a model system for advanced life support based on different microbial species and higher plants. The main objective of the LiRHiPliSMe (Literature Review of Higher Plants in Space for MELiSSA) project was to elaborate the preliminary roadmap for higher plant research activities for the MELiSSA project Phase 2 (Preliminary Space Experiments). The first task was to establish an understanding of the current knowledge concerning how higher plant will adapt to Moon/Mars physical factors different from Earth with focus on reduced gravity, space radiation, variations in magnetic field and combined effects of these factors. The literature related to how Moon/Mars physical factors can affect genetic processes, growth regulators, development, morphology, water and nutrients transport, gas exchange and metabolism of higher plants during one life cycle were collected. The possible effects of the space environment on the plant role as a food and on the mass balance in a Life Support System that includes a Higher Plant Compartment are reviewed. Based on this literature review there was made an assessment of where new or extended scientific knowledge about space factors effects on higher plant growth and development is needed. The requirements for research activities on higher plants in enclosed life support systems were identified. The required higher plant research activities for MELiSSA phase 2 both on ground and in space were placed in a timescale from the present until higher plants can be grown in closed life support systems on Moon and Mars.

Active Space Debris Removal using European Modified Launch Vehicle Upper Stages Equipped with Electrodynamic Tethers

NASA Astrophysics Data System (ADS)

Nasseri, Ali S.; Emanuelli, Matteo; Raval, Siddharth; Turconi, Andrea; Becker, Cristoph

2013-08-01

During the past few years, several research programs have assessed the current state and future evolution of the Low Earth Orbit region. These studies indicate that space debris density could reach a critical level such that there will be a continuous increase in the number of debris objects, primarily driven by debris-debris collision activity known as the Kessler effect. This cascade effect can be even more significant when intact objects as dismissed rocket bodies are involved in the collision. The majority of the studies until now have highlighted the urgency for active debris removal in the next years. An Active Debris Removal System (ADRS) is a system capable of approaching the debris object through a close-range rendezvous, establishing physical connection, stabilizing its attitude and finally de-orbiting the debris object using a type of propulsion system in a controlled manoeuvre. In its previous work, this group showed that a modified Fregat (Soyuz FG's 4th stage) or Breeze-M upper stage (Proton-M) launched from Plesetsk (Russian Federation) and equipped with an electro-dynamic tether (EDT) system can be used, after an opportune inclination's change, to de-orbit a Kosmos-3M second stage rocket body while also delivering an acceptable payload to orbit. In this paper, we continue our work on the aforementioned concept, presented at the 2012 Beijing Space Sustainability Conference, by comparing its performance to ADR missions using only chemical propulsion from the upper stage for the far approach and the de-orbiting phase. We will also update the EDT model used in our previous work and highlight some of the methods for creating physical contact with the object. Moreover, we will assess this concept also with European launch vehicles (Vega and Soyuz 2-1A) to remove space debris from space. In addition, the paper will cover some economic aspects, like the cost for the launches' operator in term of payload mass' loss at the launch. The entire debris removal mission from launch to de-orbiting of the target debris object will be analysed using Analytical Graphic Inc.'s Systems Tool Kit (STK).

On the Probabilistic Deployment of Smart Grid Networks in TV White Space.

PubMed

Cacciapuoti, Angela Sara; Caleffi, Marcello; Paura, Luigi

2016-05-10

To accommodate the rapidly increasing demand for wireless broadband communications in Smart Grid (SG) networks, research efforts are currently ongoing to enable the SG networks to utilize the TV spectrum according to the Cognitive Radio paradigm. To this aim, in this letter, we develop an analytical framework for the optimal deployment of multiple closely-located SG Neighborhood Area Networks (NANs) concurrently using the same TV spectrum. The objective is to derive the optimal values for both the number of NANs and their coverage. More specifically, regarding the number of NANs, we derive the optimal closed-form expression, i.e., the closed-form expression that assures the deployment of the maximum number of NANs in the considered region satisfying a given collision constraint on the transmissions of the NANs. Regarding the NAN coverage, we derive the optimal closed-form expression, i.e., the closed-form expression of the NAN transmission range that assures the maximum coverage of each NAN in the considered region satisfying the given collision constraint. All the theoretical results are derived by adopting a stochastic approach. Finally, numerical results validate the theoretical analysis.

Fugitives from the Hungaria region: Close encounters and impacts with terrestrial planets

NASA Astrophysics Data System (ADS)

Galiazzo, M. A.; Bazsó, Á.; Dvorak, R.

2013-08-01

Hungaria asteroids, whose orbits occupy the region in element space between 1.78

HiCAT Software Infrastructure: Safe hardware control with object oriented Python

NASA Astrophysics Data System (ADS)

Moriarty, Christopher; Brooks, Keira; Soummer, Remi

2018-01-01

High contrast imaging for Complex Aperture Telescopes (HiCAT) is a testbed designed to demonstrate coronagraphy and wavefront control for segmented on-axis space telescopes such as envisioned for LUVOIR. To limit the air movements in the testbed room, software interfaces for several different hardware components were developed to completely automate operations. When developing software interfaces for many different pieces of hardware, unhandled errors are commonplace and can prevent the software from properly closing a hardware resource. Some fragile components (e.g. deformable mirrors) can be permanently damaged because of this. We present an object oriented Python-based infrastructure to safely automate hardware control and optical experiments. Specifically, conducting high-contrast imaging experiments while monitoring humidity and power status along with graceful shutdown processes even for unexpected errors. Python contains a construct called a “context manager” that allows you define code to run when a resource is opened or closed. Context managers ensure that a resource is properly closed, even when unhandled errors occur. Harnessing the context manager design, we also use Python’s multiprocessing library to monitor humidity and power status without interrupting the experiment. Upon detecting a safety problem, the master process sends an event to the child process that triggers the context managers to gracefully close any open resources. This infrastructure allows us to queue up several experiments and safely operate the testbed without a human in the loop.

The stellar wind of an O8.5 I(f) star in M 31

NASA Technical Reports Server (NTRS)

Haser, S. M.; Lennon, D. J.; Kudritzki, R.-P.; Puls, J.; Pauldrach, A. W. A.; Bianchi, L.; Hutchings, J. B.

1995-01-01

We rediscuss the UV spectrum of OB 78#231, an O8.5 I(f) star in the Andromeda galaxy M 31, which has been obtained with the Faint Object Spectrograph on the Hubble Space Telescope by Hutchings et al. (1992). The spectrum has been re-extracted with better knowledge of background, calibration, and scattered light. The empirical analysis of the stellar wind lines results in a terminal velocity and mass loss rate similar to those typically found in comparable galactic objects. Furthermore, a comparison with an FOS spectrum of an O7 supergiant in the Small Magellanic Cloud and IUE spectra of galactic objects implies a metallicity close to galactic counterparts. These results are confirmed quantitatively by spectrum synthesis calculations using a theoretical description of O-star winds.

Contemporary Spaces of Memory - Towards Transdisciplinarity in Architecture

NASA Astrophysics Data System (ADS)

Kabrońska, Joanna

2017-10-01

The paper explores new phenomena in the contemporary practice of commemoration implemented through architecture. Architectural objects related to memory can be a place where new trends and phenomena appear earlier than in other architectural objects. The text is an attempt to prove that these new spaces of memory are a kind of laboratory where new ideas taking place in architecture and related disciplines are being tested. Research focuses on the bond between the complex and difficult problem of memory and the issue of transdisciplinarity in architecture. Over the last few decades architecture has been - in comparison to other areas - a relatively closed domain of knowledge. Contemporary places of memory - different from the traditional - may be the evidence of changes. On the basis of theoretical approaches, interdisciplinary surveys, in-field analyses and case studies the paper give insight into the relationships between architecture and other areas, emerging in the recently created spaces of memory of different types. The text indicates that today both the study and the design of such places is difficult without going beyond the field of architecture. There is a need for further extensive research, but the paper confirms the potential of this research direction. Spaces of memory offer the opportunity to capture the transformation of the discipline at the moment when the process begins.

Collaborative Commercial Space Situational Awareness

NASA Astrophysics Data System (ADS)

Kelso, T. S.; Hendrix, D.; Sibert, D.; Hall, R. A.; Therien, W.

2013-09-01

There is an increasing recognition by commercial and civil space operators of the need for space situational awareness (SSA) data to support ongoing conjunction analysis, maneuver planning, and radio frequency interference mitigation as part of daily operations. While some SSA data is available from the Joint Space Operations Center via the Space Track web site, access to raw observations and photometric data is limited due to national security considerations. These data, however, are of significant value in calibrating intra- and inter-operator orbit determination results, determining inter-system biases, and assessing operating profiles in the geostationary orbit. This paper details an ongoing collaborative effort to collect and process optical observations and photometric data using a network of low-cost telescope installations and shows how these data are being used to support ongoing operations in the Space Data Center. This presentation will demonstrate how by leveraging advance photometric processing algorithms developed for Missile Defense Agency and the Ballistic Missile Defense (BMD) mission ExoAnalytic and AGI have been able to provide actionable SSA for satellite operators from small telescopes in less than optimal viewing conditions. Space has become an increasingly cluttered environment requiring satellite operators to remain forever vigilant in order to prevent collisions to preserve their assets and prevent further cluttering the space environment. The Joint Space Operations Center (JSpOC), which tracks all objects in earth orbit, reports possible upcoming conjunctions to operators by providing Conjunction Summary Messages (CSMs). However due to large positional uncertainties in the forward predicted position of space objects at the time closest approach the volume of CSMs is excessive to the point that maneuvers in response to CSMs without additional screening is cost prohibitive. CSSI and the Space Data Association have been able to screen most CSMs by using more accurate operator ephemeris. By screening with operator ephemeris alone they have been able to demonstrate that safety limits will not be exceeded in a good number of these encounters and that extra delta-V need to not be expended in a Collision Avoidance (COLA) maneuver. However there remains a decent portion of alerts that may warrant action especially when the secondary object is an uncontrolled space object such as a dead satellite or rocket body. By dynamically tasking the ESpOC observatories to provide real-time tracking and photometric characterization of the secondary objects in response to these CSMs satellite operators benefit from an additional method of conjunction screening. The refined tracks and conjunction assessments obtained by ESpOC screening allows operators to safely reduce the number of COLAs performed in response to safe close approaches and provide optimized COLA maneuver planning in response to validated threats.

Early Impacts of a Human-in-the-Loop Evaluation in a Space Vehicle Mock-up Facility

NASA Technical Reports Server (NTRS)

Byrne, Vicky; Vos, Gordon; Whitmore, Mihriban

2008-01-01

The development of a new space vehicle, the Orion Crew Exploration Vehicle (CEV), provides Human Factors engineers an excellent opportunity to have an impact early in the design process. This case study highlights a Human-in-the-Loop (HITL) evaluation conducted in a Space Vehicle Mock-Up Facility and will describe the human-centered approach and how the findings are impacting design and operational concepts early in space vehicle design. The focus of this HITL evaluation centered on the activities that astronaut crewmembers would be expected to perform within the functional internal volume of the Crew Module (CM) of the space vehicle. The primary objective was to determine if there are aspects of a baseline vehicle configuration that would limit or prevent the performance of dynamically volume-driving activities (e.g. six crewmembers donning their suits in an evacuation scenario). A second objective was to step through concepts of operations for known systems and evaluate them in integrated scenarios. The functional volume for crewmember activities is closely tied to every aspect of system design (e.g. avionics, safety, stowage, seats, suits, and structural support placement). As this evaluation took place before the Preliminary Design Review of the space vehicle with some designs very early in the development, it was not meant to determine definitely that the crewmembers could complete every activity, but rather to provide inputs that could improve developing designs and concepts of operations definition refinement.

High temperature superconductor dc SQUID micro-susceptometer for room temperature objects

NASA Astrophysics Data System (ADS)

Faley, M. I.; Pratt, K.; Reineman, R.; Schurig, D.; Gott, S.; Atwood, C. G.; Sarwinski, R. E.; Paulson, D. N.; Starr, T. N.; Fagaly, R. L.

2004-05-01

We have developed a scanning magnetic microscope (SMM) with 25 µm resolution in spatial position for the magnetic features of room temperature objects. The microscope consists of a high-temperature superconductor (HTS) dc SQUID sensor, suspended in vacuum with a self-adjusting standoff, close spaced liquid nitrogen Dewar, X-Y scanning stage and a computer control system. The HTS SQUIDs were optimized for better spatial and field resolutions for operation at liquid nitrogen temperature. Measured inside a magnetic shield, the 10 pT Hz-1/2 typical noise of the SQUIDs is white down to frequencies of about 10 Hz, increasing up to about 20 pT Hz-1/2 at 1 Hz. The microscope is mounted on actively damped platforms, which negate vibrations from the environment as well as damping internal stepper motor noises. A high-resolution video telescope and a 1 µm precision z-axis positioning system allow a close positioning of the sample under the sensor. The ability of the sensors to operate in unshielded environmental conditions with magnetic fields up to about 15 G allowed us to perform 2D mapping of the local ac and dc susceptibility of the objects.

Spacing, Thinning, and Pruning Practices for Young Cottonwood Plantations

Treesearch

Leon S. Minckler

1970-01-01

The 5-year growth of cottonwood trees planted at five spacing levels is summarized. Wide spacing resulted in better diameter and height growth, but less total wood production per acre than close spacing. Early thinning of closely spaced trees did not maintain diameter growth equal to that of trees with initial wide spacing.

Determination of Non-gravitational Effects in the Motion of Near-Sun Objects 321P, 322P, 323P, and 342P

NASA Astrophysics Data System (ADS)

Emel'yanenko, V. V.; Naroenkov, S. A.

2018-01-01

At the beginning of this century, the SOHO space observatory discovered near-Sun comets with perihelion distances q ≈ 0.05 AU, which remained observable over several close encounters with the Sun. This became one of the surprises in studying the small bodies of the Solar System. Currently, there are objects that have already been observed in four (342P) and five (321P, 322P, and 323P) apparitions. In the present work, the estimates of nongravitational effects are obtained for these objects based on the pair-wise linkage of the apparitions. The calculations show that the observations of these objects are poorly represented if solely the gravitational forces are considered. The magnitude of nongravitational effects in the semimajor axis noticeably changes with time. The motion of all comets is significantly affected by the components of nongravitational forces that are perpendicular to the orbital plane.

Tapered whiskers are required for active tactile sensation.

PubMed

Hires, Samuel Andrew; Pammer, Lorenz; Svoboda, Karel; Golomb, David

2013-11-19

Many mammals forage and burrow in dark constrained spaces. Touch through facial whiskers is important during these activities, but the close quarters makes whisker deployment challenging. The diverse shapes of facial whiskers reflect distinct ecological niches. Rodent whiskers are conical, often with a remarkably linear taper. Here we use theoretical and experimental methods to analyze interactions of mouse whiskers with objects. When pushed into objects, conical whiskers suddenly slip at a critical angle. In contrast, cylindrical whiskers do not slip for biologically plausible movements. Conical whiskers sweep across objects and textures in characteristic sequences of brief sticks and slips, which provide information about the tactile world. In contrast, cylindrical whiskers stick and remain stuck, even when sweeping across fine textures. Thus the conical whisker structure is adaptive for sensor mobility in constrained environments and in feature extraction during active haptic exploration of objects and surfaces. DOI: http://dx.doi.org/10.7554/eLife.01350.001.

A statistical learning strategy for closed-loop control of fluid flows

NASA Astrophysics Data System (ADS)

Guéniat, Florimond; Mathelin, Lionel; Hussaini, M. Yousuff

2016-12-01

This work discusses a closed-loop control strategy for complex systems utilizing scarce and streaming data. A discrete embedding space is first built using hash functions applied to the sensor measurements from which a Markov process model is derived, approximating the complex system's dynamics. A control strategy is then learned using reinforcement learning once rewards relevant with respect to the control objective are identified. This method is designed for experimental configurations, requiring no computations nor prior knowledge of the system, and enjoys intrinsic robustness. It is illustrated on two systems: the control of the transitions of a Lorenz'63 dynamical system, and the control of the drag of a cylinder flow. The method is shown to perform well.

In-Space Radiator Shape Optimization using Genetic Algorithms

NASA Technical Reports Server (NTRS)

Hull, Patrick V.; Kittredge, Ken; Tinker, Michael; SanSoucie, Michael

2006-01-01

Future space exploration missions will require the development of more advanced in-space radiators. These radiators should be highly efficient and lightweight, deployable heat rejection systems. Typical radiators for in-space heat mitigation commonly comprise a substantial portion of the total vehicle mass. A small mass savings of even 5-10% can greatly improve vehicle performance. The objective of this paper is to present the development of detailed tools for the analysis and design of in-space radiators using evolutionary computation techniques. The optimality criterion is defined as a two-dimensional radiator with a shape demonstrating the smallest mass for the greatest overall heat transfer, thus the end result is a set of highly functional radiator designs. This cross-disciplinary work combines topology optimization and thermal analysis design by means of a genetic algorithm The proposed design tool consists of the following steps; design parameterization based on the exterior boundary of the radiator, objective function definition (mass minimization and heat loss maximization), objective function evaluation via finite element analysis (thermal radiation analysis) and optimization based on evolutionary algorithms. The radiator design problem is defined as follows: the input force is a driving temperature and the output reaction is heat loss. Appropriate modeling of the space environment is added to capture its effect on the radiator. The design parameters chosen for this radiator shape optimization problem fall into two classes, variable height along the width of the radiator and a spline curve defining the -material boundary of the radiator. The implementation of multiple design parameter schemes allows the user to have more confidence in the radiator optimization tool upon demonstration of convergence between the two design parameter schemes. This tool easily allows the user to manipulate the driving temperature regions thus permitting detailed design of in-space radiators for unique situations. Preliminary results indicate an optimized shape following that of the temperature distribution regions in the "cooler" portions of the radiator. The results closely follow the expected radiator shape.

NASA Research Announcement Phase 2 Final Report for the Development of a Power Assisted Space Suit Glove

NASA Technical Reports Server (NTRS)

Lingo, Robert; Cadogan, Dave; Sanner, Rob; Sorenson, Beth

1997-01-01

The main goal of this program was to develop an unobtrusive power-assisted EVA glove metacarpalphalangeal (MCP) joint that could provide the crew member with as close to nude body performance as possible, and to demonstrate the technology feasibility of power assisted space suit components in general. The MCP joint was selected due to its being representative of other space suit joints, such as the shoulder, hip and carpometacarpal joint, that would also greatly benefit from this technology. In order to meet this objective, a development team of highly skilled and experienced personnel was assembled. The team consisted of two main entities. The first was comprised of ILC's experienced EVA space suit glove designers, who had the responsibility of designing and fabricating a low torque MCP joint which would be compatible with power assisted technology. The second part of the team consisted of space robotics experts from the University of Maryland's Space Systems Laboratory. This team took on the responsibility of designing and building the robotics aspects of the power-assist system. Both parties addressed final system integration responsibilities.

Object Locating System

NASA Technical Reports Server (NTRS)

Arndt, G. Dickey (Inventor); Carl, James R. (Inventor)

2000-01-01

A portable system is provided that is operational for determining, with three dimensional resolution, the position of a buried object or approximately positioned object that may move in space or air or gas. The system has a plurality of receivers for detecting the signal front a target antenna and measuring the phase thereof with respect to a reference signal. The relative permittivity and conductivity of the medium in which the object is located is used along with the measured phase signal to determine a distance between the object and each of the plurality of receivers. Knowing these distances. an iteration technique is provided for solving equations simultaneously to provide position coordinates. The system may also be used for tracking movement of an object within close range of the system by sampling and recording subsequent position of the object. A dipole target antenna. when positioned adjacent to a buried object, may be energized using a separate transmitter which couples energy to the target antenna through the medium. The target antenna then preferably resonates at a different frequency, such as a second harmonic of the transmitter frequency.

The DLR AsteroidFinder for NEOs

NASA Astrophysics Data System (ADS)

Mottola, Stefano; Kuehrt, Ekkehard; Michaelis, Harald; Hoffmann, Harald; Spietz, Peter; Jansen, Frank; Thimo Grundmann, Jan; Hahn, Gerhard; Montenegro, Sergio; Findlay, Ross; Boerner, Anko; Messina, Gabriele; Behnke, Thomas; Tschentscher, Matthias; Scheibe, Karsten; Mertens, Volker; Heidecke, Ansgar

Potential Earth-impacting asteroids that spend most of their time interior to Earth's orbit are extremely difficult to be observed from the ground and remain largely undetected. Firstly, they are mostly located at small solar elongations, where the sky brightness and their faintness due to the large phase angle prevents their discovery. Secondly, these objects tend to have very long synodic orbital periods, which makes observation opportunities rare and impact warning times short. Because of these limitations, even the advent of next generation ground-based asteroid surveys is not likely to radically improve the situation (Veres et al. Icarus 203, p472, 2009). On the other hand, a small satellite with a suitable design can observe close to the Sun and detect these objects efficiently against a dark sky background. For this reason, DLR, the German Aerospace Center, has selected AsteroidFinder as the first experiment to be launched under its new compact satellite national program. The primary goal of the mission is to detect and characterize Near Earth Objects (NEOs), with a particular focus on the population of objects completely contained within Earth's orbit (IEOs or Inner Earth Objects). Current dynamical models predict the existence of more than 1000 such objects down to a size of 100m, of which, due to the abovementioned observation difficulties, only 10 have been discovered to date. Benefitting from the vantage point of a Low Earth Orbit (LEO), AsteroidFinder makes use of a small optical telescope to scan those regions of the sky that are close to the Sun, and therefore beyond the reach of ground based observatories. By estimating the population, the size and the orbital distribution of IEOs, AsteroidFinder will contribute to our knowledge of the inner Solar System, and to the assessment of the impact hazard for the Earth. A secondary goal of the mission is to demonstrate techniques that enable the space-based detection of space debris in the cm size range. With these mission goals, AsteroidFinder also addresses the programmatic goals of the ESA SSA initiative, both for the NEO and space debris domain. The AsteroidFinder mission is based on the DLR SSB standard platform, it employs a 400-cm2 clear-aperture, off-axis design telescope and an array of new technology CCDs. AsteroidFinder, which is presently in its Phase-B development stage, is planned to launch in 2013 with a one-year nominal mission duration and the possibility of an extension.

Active Debris Removal Using Modified Launch Vehicle Upper Stages

NASA Astrophysics Data System (ADS)

Nasseri, S. Ali; Emanuelli, Matteo; Raval, Siddharth; Turconi, Andrea

2013-09-01

During the past few years, several research programs have assessed the current state and future evolution of space debris in the Low Earth Orbit region. These studies indicate that space debris density could reach a critical level such that there will be a continuous increase in the number of debris objects, primarily driven by debris-debris collision activity known as the Kessler effect. These studies also highlight the urgency for active debris removal.An Active Debris Removal System (ADRS) is capable of approaching the debris object through a close-range rendezvous, stabilizing its attitude, establishing physical contact, and finally de-orbiting the debris object. The de-orbiting phase could be powered by propulsion systems such as chemical rockets or electrodynamic tether (EDT) systems.The aim of this project is to model and evaluate a debris removal mission in which an adapted rocket upper stage, equipped with an electrodynamic tether (EDT) system, is employed for de-orbiting a debris object. This ADRS package is installed initially as part of a launch vehicle on a normal satellite deployment mission, and a far-approach manoeuvre will be required to align the ADRS' orbit with that of the target debris. We begin by selecting a suitable target debris and launch vehicle, and then proceed with modelling the entire debris removal mission from launch to de-orbiting of the target debris object using Analytical Graphic Inc.'s Systems Tool Kit (STK).

[Survivability and morphologic anomalies in higher plants wolffia arrhiza following exposure to heavy ions of the galactic space radiation].

PubMed

Nevzgodina, L V; Kaminskaia, E V; Maksimova, E N; Fatsius, R; Sherrer, K; Shtraukh, V

2000-01-01

Experimental data on the effects of spaceflight factors, space radiation in particular, on higher plant Wolffia arrhiza firstly exposed in the "Bioblock" assembly and measurements made by physical track detectors of heavy ions (HI) are presented. Death of individual Wolffia plants and morphologic anomalies were the basic evaluation criteria. The peculiar feature of this biological object consists in the possibility to reveal delayed effects after 1-2 months since space flight as Wolffia has a high rate of vegetative reproduction. German investigators through microscopic examination of track detectors performed identification of individual plants affected by HI. With specially developed software and a coordinate system of supposition of biolayers and track detectors with the accuracy of 1 micron, tracks and even separate sections of individual HI tracks were determined in biological objects. Thereafter each Wolffia plant hit by HI was examined and data were compared with other variants. As a result, correlation between Wolffia death rate and morphologic anomalies were determined at different times post flight and topography of HI tracks was found. It is hypothesized that morphological anomalies in Walffia were caused by direct hits of plant germs by heavy ions or close passage of particles.

Space Object Collision Probability via Monte Carlo on the Graphics Processing Unit

NASA Astrophysics Data System (ADS)

Vittaldev, Vivek; Russell, Ryan P.

2017-09-01

Fast and accurate collision probability computations are essential for protecting space assets. Monte Carlo (MC) simulation is the most accurate but computationally intensive method. A Graphics Processing Unit (GPU) is used to parallelize the computation and reduce the overall runtime. Using MC techniques to compute the collision probability is common in literature as the benchmark. An optimized implementation on the GPU, however, is a challenging problem and is the main focus of the current work. The MC simulation takes samples from the uncertainty distributions of the Resident Space Objects (RSOs) at any time during a time window of interest and outputs the separations at closest approach. Therefore, any uncertainty propagation method may be used and the collision probability is automatically computed as a function of RSO collision radii. Integration using a fixed time step and a quartic interpolation after every Runge Kutta step ensures that no close approaches are missed. Two orders of magnitude speedups over a serial CPU implementation are shown, and speedups improve moderately with higher fidelity dynamics. The tool makes the MC approach tractable on a single workstation, and can be used as a final product, or for verifying surrogate and analytical collision probability methods.

BLUE STRAGGLER EVOLUTION CAUGHT IN THE ACT IN THE LARGE MAGELLANIC CLOUD GLOBULAR CLUSTER HODGE 11

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Chengyuan; De Grijs, Richard; Liu Xiangkun

High-resolution Hubble Space Telescope imaging observations show that the radial distribution of the field-decontaminated sample of 162 'blue straggler' stars (BSs) in the 11.7{sup +0.2}{sub -0.1} Gyr old Large Magellanic Cloud cluster Hodge 11 exhibits a clear bimodality. In combination with their distinct loci in color-magnitude space, this offers new evidence in support of theoretical expectations that suggest different BS formation channels as a function of stellar density. In the cluster's color-magnitude diagram, the BSs in the inner 15'' (roughly corresponding to the cluster's core radius) are located more closely to the theoretical sequence resulting from stellar collisions, while thosemore » in the periphery (at radii between 85'' and 100'') are preferentially found in the region expected to contain objects formed through binary mass transfer or coalescence. In addition, the objects' distribution in color-magnitude space provides us with the rare opportunity in an extragalactic environment to quantify the evolution of the cluster's collisionally induced BS population and the likely period that has elapsed since their formation epoch, which we estimate to have occurred {approx}4-5 Gyr ago.« less

Structural Analysis of a Magnetically Actuated Silicon Nitride Micro-Shutter for Space Applications

NASA Technical Reports Server (NTRS)

Loughlin, James P.; Fettig, Rainer K.; Moseley, S. Harvey; Kutyrev, Alexander S.; Mott, D. Brent; Obenschain, Arthur F. (Technical Monitor)

2002-01-01

Finite element models have been created to simulate the electrostatic and electromagnetic actuation of a 0.5 micrometers silicon nitride micro-shutter for use in a spacebased Multi-object Spectrometer (MOS). The microshutter uses a torsion hinge to go from the closed, 0 degree, position, to the open, 90 degree position. Stresses in the torsion hinge are determined with a large deformation nonlinear finite element model. The simulation results are compared to experimental measurements of fabricated micro-shutter devices.

COPPER Students - ELaNa IV

NASA Image and Video Library

2013-07-11

The Close Orbiting Propellant Plume Elemental Recognition (COPPER) was developed by students from St. Louis University as a technology demonstration mission whose objective is to test the suitability of a commercially-available compact uncooled microbolometer (tiny infrared camera) array for scientific imagery of Earth in the long-wave infrared range (LWIR, 7-13 microns). Launched by NASA’s CubeSat Launch Initiative on the ELaNa IV mission as an auxiliary payload aboard the U.S. Air Force-led Operationally Responsive Space (ORS-3) Mission on November 19, 2013.

GaAs shallow-homojunction solar cells

NASA Technical Reports Server (NTRS)

Fan, J. C.

1980-01-01

With the objective of demonstrating the feasibility of fabricating 2 x 2 cm efficient, shallow homojunction GaAs solar cells for space applications, this program addresses the basic problems of material preparation and device fabrication. Significant progress was made and conversion efficiencies close to 16 percent at AM0 were obtained on 2 x 2 cm cells. Measurements and computer analyses on the n(+)/p/p(+) shallow homojunction cells indicate that such cell configuration should be very resistant to 1 MeV electron irradiation.

In Vivo Force Decay of Niti Closed Coil Springs

PubMed Central

Cox, Crystal; Nguyen, Tung; Koroluk, Lorne; Ko, Ching-Chang

2014-01-01

Introduction Nickel-titanium (NiTi) closed coil springs are purported to deliver constant forces over extended ranges of activation and working times. In vivo studies supporting this claim are limited. The objective of this study is to evaluate changes in force decay properties of NiTi closed coil springs after clinical use. Methods Pseudoelastic force-deflection curves for 30 NiTi coil springs (used intra-orally) and 15 matched laboratory control springs (simulated intra-oral conditions - artificial saliva, 37°C) were tested pre- and post-retrieval via Dynamic Mechanical Analysis (DMA) and the Instron machine, respectively, to evaluate amount of force loss and hysteresis change following 4, 8, or 12 weeks of working time (n=10 per group). Effect of the oral environment and clinical use on force properties were evaluated by comparing in vivo and in vitro data. Results The springs studied showed a statistically significant decrease in force (~12%) following 4 weeks of clinical use (p<0.01), with a further significant decrease (~7%) from 4–8 weeks (p=0.03) and force levels appearing to remain steady thereafter. Clinical space closure at an average rate of 0.91mm per month was still observed despite this decrease in force. In vivo and in vitro force loss data were not statistically different. Conclusions NiTi closed coil springs do not deliver constant forces when used intra-orally, but they still allow for space closure rates of ~1mm/month. PMID:24703289

A clinical study of space closure with nickel-titanium closed coil springs and an elastic module.

PubMed

Samuels, R H; Rudge, S J; Mair, L H

1998-07-01

A previous study has shown that a 150-gram nickel-titanium closed coil spring (Sentalloy, GAC International Inc.) closed spaces more quickly and more consistently than an elastic module (Alastik, Unitec/3M). This study used the same friction sensitive sliding mechanics of pitting the six anterior teeth against the second bicuspid and first molars, to examine the rate of space closure of 100-gram and 200-gram nickel-titanium closed coil springs. The results for the three springs and elastic module were compared. The nickel-titanium closed coil springs produced a more consistent space closure than the elastic module. The 150- and 200-gram springs produced a faster rate of space closure than the elastic module or the 100-gram spring. No significant difference was noted between the rates of closure for the 150- and the 200-gram springs.

Design and fabrication of robotic gripper for grasping in minimizing contact force

NASA Astrophysics Data System (ADS)

Heidari, Hamidreza; Pouria, Milad Jafary; Sharifi, Shahriar; Karami, Mahmoudreza

2018-03-01

This paper presents a new method to improve the kinematics of robot gripper for grasping in unstructured environments, such as space operations. The robot gripper is inspired from the human hand and kept the hand design close to the structure of human fingers to provide successful grasping capabilities. The main goal is to improve kinematic structure of gripper to increase the grasping capability of large objects, decrease the contact forces and makes a successful grasp of various objects in unstructured environments. This research will describe the development of a self-adaptive and reconfigurable robotic hand for space operations through mechanical compliance which is versatile, robust and easy to control. Our model contains two fingers, two-link and three-link, with combining a kinematic model of thumb index. Moreover, some experimental tests are performed to examine the effectiveness of the hand-made in real, unstructured tasks. The results represent that the successful grasp range is improved about 30% and the contact forces is reduced approximately 10% for a wide range of target object size. According to the obtained results, the proposed approach provides an accommodative kinematic model which makes the better grasping capability by fingers geometries for a robot gripper.

The Space Operations Simulation Center (SOSC) and Closed-Loop Hardware Testing for Orion Rendezvous System Design

NASA Technical Reports Server (NTRS)

Milenkovic, Zoran; DSouza, Christopher; Huish, David; Bendle, John; Kibler, Angela

2012-01-01

The exploration goals of Orion / MPCV Project will require a mature Rendezvous, Proximity Operations and Docking (RPOD) capability. Ground testing autonomous docking with a next-generation sensor such as the Vision Navigation Sensor (VNS) is a critical step along the path of ensuring successful execution of autonomous RPOD for Orion. This paper will discuss the testing rationale, the test configuration, the test limitations and the results obtained from tests that have been performed at the Lockheed Martin Space Operations Simulation Center (SOSC) to evaluate and mature the Orion RPOD system. We will show that these tests have greatly increased the confidence in the maturity of the Orion RPOD design, reduced some of the latent risks and in doing so validated the design philosophy of the Orion RPOD system. This paper is organized as follows: first, the objectives of the test are given. Descriptions of the SOSC facility, and the Orion RPOD system and associated components follow. The details of the test configuration of the components in question are presented prior to discussing preliminary results of the tests. The paper concludes with closing comments.

Closed geometric models in medical applications

NASA Astrophysics Data System (ADS)

Jagannathan, Lakshmipathy; Nowinski, Wieslaw L.; Raphel, Jose K.; Nguyen, Bonnie T.

1996-04-01

Conventional surface fitting methods give twisted surfaces and complicates capping closures. This is a typical character of surfaces that lack rectangular topology. We suggest an algorithm which overcomes these limitations. The analysis of the algorithm is presented with experimental results. This algorithm assumes the mass center lying inside the object. Both capping closure and twisting are results of inadequate information on the geometric proximity of the points and surfaces which are proximal in the parametric space. Geometric proximity at the contour level is handled by mapping the points along the contour onto a hyper-spherical space. The resulting angular gradation with respect to the centroid is monotonic and hence avoids the twisting problem. Inter-contour geometric proximity is achieved by partitioning the point set based on the angle it makes with the respective centroids. Avoidance of capping complications is achieved by generating closed cross curves connecting curves which are reflections about the abscissa. The method is of immense use for the generation of the deep cerebral structures and is applied to the deep structures generated from the Schaltenbrand- Wahren brain atlas.

Overcoming the Subject-Object Dichotomy in Urban Modeling: Axial Maps as Geometric Representations of Affordances in the Built Environment

PubMed Central

Marcus, Lars

2018-01-01

The world is witnessing unprecedented urbanization, bringing extreme challenges to contemporary practices in urban planning and design. This calls for improved urban models that can generate new knowledge and enhance practical skill. Importantly, any urban model embodies a conception of the relation between humans and the physical environment. In urban modeling this is typically conceived of as a relation between human subjects and an environmental object, thereby reproducing a humans-environment dichotomy. Alternative modeling traditions, such as space syntax that originates in architecture rather than geography, have tried to overcome this dichotomy. Central in this effort is the development of new representations of urban space, such as in the case of space syntax, the axial map. This form of representation aims to integrate both human behavior and the physical environment into one and the same description. Interestingly, models based on these representations have proved to better capture pedestrian movement than regular models. Pedestrian movement, as well as other kinds of human flows in urban space, is essential for urban modeling, since increasingly flows of this kind are understood as the driver in urban processes. Critical for a full understanding of space syntax modeling is the ontology of its' representations, such as the axial map. Space syntax theory here often refers to James Gibson's “Theory of affordances,” where the concept of affordances, in a manner similar to axial maps, aims to bridge the subject-object dichotomy by neither constituting physical properties of the environment or human behavior, but rather what emerges in the meeting between the two. In extension of this, the axial map can be interpreted as a representation of how the physical form of the environment affords human accessibility and visibility in urban space. This paper presents a close examination of the form of representations developed in space syntax methodology, in particular in the light of Gibson's “theory of affordances.“ The overarching aim is to contribute to a theoretical framework for urban models based on affordances, which may support the overcoming of the subject-object dichotomy in such models, here deemed essential for a greater social-ecological sustainability of cities. PMID:29731726

Evaluation of the geometric stability and the accuracy potential of digital cameras — Comparing mechanical stabilisation versus parameterisation

NASA Astrophysics Data System (ADS)

Rieke-Zapp, D.; Tecklenburg, W.; Peipe, J.; Hastedt, H.; Haig, Claudia

Recent tests on the geometric stability of several digital cameras that were not designed for photogrammetric applications have shown that the accomplished accuracies in object space are either limited or that the accuracy potential is not exploited to the fullest extent. A total of 72 calibrations were calculated with four different software products for eleven digital camera models with different hardware setups, some with mechanical fixation of one or more parts. The calibration procedure was chosen in accord to a German guideline for evaluation of optical 3D measuring systems [VDI/VDE, VDI/VDE 2634 Part 1, 2002. Optical 3D Measuring Systems-Imaging Systems with Point-by-point Probing. Beuth Verlag, Berlin]. All images were taken with ringflashes which was considered a standard method for close-range photogrammetry. In cases where the flash was mounted to the lens, the force exerted on the lens tube and the camera mount greatly reduced the accomplished accuracy. Mounting the ringflash to the camera instead resulted in a large improvement of accuracy in object space. For standard calibration best accuracies in object space were accomplished with a Canon EOS 5D and a 35 mm Canon lens where the focusing tube was fixed with epoxy (47 μm maximum absolute length measurement error in object space). The fixation of the Canon lens was fairly easy and inexpensive resulting in a sevenfold increase in accuracy compared with the same lens type without modification. A similar accuracy was accomplished with a Nikon D3 when mounting the ringflash to the camera instead of the lens (52 μm maximum absolute length measurement error in object space). Parameterisation of geometric instabilities by introduction of an image variant interior orientation in the calibration process improved results for most cameras. In this case, a modified Alpa 12 WA yielded the best results (29 μm maximum absolute length measurement error in object space). Extending the parameter model with FiBun software to model not only an image variant interior orientation, but also deformations in the sensor domain of the cameras, showed significant improvements only for a small group of cameras. The Nikon D3 camera yielded the best overall accuracy (25 μm maximum absolute length measurement error in object space) with this calibration procedure indicating at the same time the presence of image invariant error in the sensor domain. Overall, calibration results showed that digital cameras can be applied for an accurate photogrammetric survey and that only a little effort was sufficient to greatly improve the accuracy potential of digital cameras.

Space life sciences: closed ecological systems: earth and space applications.

PubMed

2005-01-01

This issue contains peer-reviewed papers from a workshop on Closed Ecological Systems: Earth and Space Applications at the 35th COSPAR General Assembly in Paris, France, convened in July 2004. The contributions reflected the wide range of international work in the field, especially Europe, Russia, Japan, and the United States. The papers are arranged according to four main themes: 1) Methods of evaluation and theory of closed ecological systems; 2) Reports from recent experiments in closed ecological system facilities; 3) Bioregenerative technologies to advance degree of closure and cycling; and 4) Laboratory studies of small closed ecological systems.

Dancing in the Dark: New Brown Dwarf Binaries from Kernel Phase Interferometry

NASA Astrophysics Data System (ADS)

Pope, Benjamin; Martinache, Frantz; Tuthill, Peter

2013-04-01

This paper revisits a sample of ultracool dwarfs in the solar neighborhood previously observed with the Hubble Space Telescope's NICMOS NIC1 instrument. We have applied a novel high angular resolution data analysis technique based on the extraction and fitting of kernel phases to archival data. This was found to deliver a dramatic improvement over earlier analysis methods, permitting a search for companions down to projected separations of ~1 AU on NIC1 snapshot images. We reveal five new close binary candidates and present revised astrometry on previously known binaries, all of which were recovered with the technique. The new candidate binaries have sufficiently close separation to determine dynamical masses in a short-term observing campaign. We also present four marginal detections of objects which may be very close binaries or high-contrast companions. Including only confident detections within 19 pc, we report a binary fraction of at least \\epsilon _b = 17.2^{+5.7}_{-3.7} %. The results reported here provide new insights into the population of nearby ultracool binaries, while also offering an incisive case study of the benefits conferred by the kernel phase approach in the recovery of companions within a few resolution elements of the point-spread function core. Based on observations performed with the NASA/ESA Hubble Space Telescope. The Hubble observations are associated with proposal ID 10143 and 10879 and were obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

The CEOS Atmospheric Composition Constellation: Enhancing the Value of Space-Based Observations

NASA Technical Reports Server (NTRS)

Eckman, Richard; Zehner, Claus; Al-Saadi, Jay

2015-01-01

The Committee on Earth Observation Satellites (CEOS) coordinates civil space-borne observations of the Earth. Participating agencies strive to enhance international coordination and data exchange and to optimize societal benefit. In recent years, CEOS has collaborated closely with the Group on Earth Observations (GEO) in implementing the Global Earth Observing System of Systems (GEOSS) space-based objectives. The goal of the CEOS Atmospheric Composition Constellation (ACC) is to collect and deliver data to improve monitoring, assessment and predictive capabilities for changes in the ozone layer, air quality and climate forcing associated with changes in the environment through coordination of existing and future international space assets. A project to coordinate and enhance the science value of a future constellation of geostationary sensors measuring parameters relevant to air quality supports the forthcoming European Sentinel-4, Korean GEMS, and US TEMPO missions. Recommendations have been developed for harmonization to mutually improve data quality and facilitate widespread use of the data products.

10 day flight performance of the plant generic bioprocessing apparatus (PGBA) plant growth facility aboard STS-77

NASA Astrophysics Data System (ADS)

Hoehn, Alex; Chamberlain, Dale J.; Forsyth, Sasha W.; Hanna, David S.; Scovazzo, Paul; Horner, Michael B.; Stodieck, Louis S.; Todd, Paul; Heyenga, A. Gerard; Kliss, Mark H.; Bula, Raymond; Yetka, Robert

1997-01-01

PGBA, a plant growth facility developed for space flight biotechnology research, successfully grew a total of 30 plants in a closed, multi-crop chamber for 10 days aboard the Space Shuttle Endeavor (STS-77). Artemisia annua, Catharanthus roseus, Pinus taeda, Spinacia oleracea and Trifolium repens were the five species studied during this mission. The primary mission objectives were to study the effects of microgravity for commercial and pharmaceutical production purposes. PGBA is a payload that represents a consortium of interests including BioServe Space Technologies (payload sponsor), NASA Ames Research Center (Controlled Ecological Life Support System, CELSS, Flight Program), Wisconsin Center for Space Automation and Robotics (WCSAR), and industrial affiliates (spaceflight effects on plants and formation of plant products such as pharmaceuticals). Although BioServe is responsible for the flight hardware development and integration of PGBA, NASA Ames, WSCAR and industrial affiliates provide significant hardware subsystems and technical biological expertise support.

Divergence is not enough: the use of ecological niche models for the validation of taxon boundaries.

PubMed

Dagnino, D; Minuto, L; Casazza, G

2017-11-01

Delimiting taxon boundaries is crucial for any evolutionary research and conservation regulation. In order to avoid mistaken description of species, the approach of integrative taxonomy recommends considering multidisciplinary lines of evidence, including ecology. Unfortunately, ecological data are often difficult to quantify objectively. Here we test and discuss the potential use of ecological niche models for validating taxon boundaries, using three pairs of closely related plant taxa endemic to the south-western Alps as a case study. We also discuss the application of ecological niche models for species delimitation and the implementation of different approaches. Niche overlap, niche equivalency and niche similarity were assessed both in multidimensional environmental space and in geographic space to look for differences in the niche of three pairs of closely related plant taxa. We detected a high degree of niche differentiation between taxa although this result seems not due to differences in habitat selection. The different statistical tests gave contrasting outcomes between environmental and geographic spaces. According to our results, niche divergence does not seem to support taxon boundaries at species level, but may have had important consequences for local adaptation and in generating phenotypic diversity at intraspecific level. Environmental space analysis should be preferred to geographic space as it provides more clear results. Even if the different analyses widely disagree in their conclusions about taxon boundaries, our study suggests that ecological niche models may help taxonomists to reach a decision. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

Kuiper Belt Objects Along the Pluto-Express Path

NASA Technical Reports Server (NTRS)

Jewitt, David (Principal Investigator)

1997-01-01

The science objective of this work is to identify objects in the Kuiper Belt which will, in the 5 years following Pluto encounter, be close to the flight path of NASA's Pluto Express. Our hope is that we will find a Kuiper Belt object or objects close enough that a spacecraft flyby will be possible. If we find a suitable object, the science yield of Pluto Express will be substantially enhanced. The density of objects in the Kuiper Belt is such that we are reasonably likely to find an object close enough to the flight path that on-board gas thrusters can effect a close encounter.

Hydropower application of confined space regulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Franseen, H.W.

1995-12-31

OSHA`s {open_quotes}Permit Required Confined Space{close_quotes} rules, 1910.146, became effective April 15, 1993. Their rules define a {open_quotes}confined space{close_quotes} and {open_quotes}permit required confined space{close_quotes}; provide general requirements for those entering the confined space, for the attendant and entry supervisor; define what a confined space program and permit system should be; and describe training requirements and rescue considerations. Tapoco Inc., began preparing confined space procedures in 1992 using Alcoa Engineering Standards and OSHA`s proposed rules. A joint union management team was formed, and this team began evaluating spaces which meet the confined space definition. In 1993, employees were trained, and all entriesmore » into spaces were done according to Alcoa`s and OSHA`s proposed rules. Rescue teams have been trained at each site. Some unique confined spaces and or unique entry conditions have been encountered which have required extensive evaluation.« less

Neighborhood and healthy aging in a German city: distances to green space and senior service centers and their associations with physical constitution, disability, and health-related quality of life.

PubMed

Vogt, Susanne; Mielck, Andreas; Berger, Ursula; Grill, Eva; Peters, Annette; Döring, Angela; Holle, Rolf; Strobl, Ralf; Zimmermann, Anja-Kerstin; Linkohr, Birgit; Wolf, Kathrin; Kneißl, Klaus; Maier, Werner

2015-12-01

The composition of the residential environment may have an independent influence on health, especially in older adults. In this cross-sectional study, we examined the associations between proximity to two features of the residential environment (green space and senior service centers) and three aspects of healthy aging (self-rated physical constitution, disability, and health-related quality of life). We included 1711 inhabitants from the city of Augsburg, Germany, aged 65 years or older, who participated in the KORA-Age study conducted in 2008/2009. We calculated the Euclidian distances between each participant's residential address and the nearest green space or senior service center, using a geographic information system. Multilevel logistic regression models were fitted to analyze the associations, controlling for demographic and socioeconomic factors. Contrary to expectations, we did not find clear associations between the distances to the nearest green space or senior service center and any of the examined aspects of healthy aging. The importance of living close to green space may largely depend on the study location. The city of Augsburg is relatively small (about 267,000 inhabitants) and has a high proportion of greenness. Thus, proximity to green space may not be as important as in a densely populated metropolitan area. Moreover, an objectively defined measure of access such as Euclidian distance may not reflect the actual use. Future studies should try to assess the importance of resources of the residential environment not only objectively, but also from the resident's perspective.

Mitigation of Collision Hazard for the International Space Station (ISS) from Globally Launched Objects

NASA Astrophysics Data System (ADS)

Schultz, Eric D.; Wilde, Paul D.

2013-09-01

For the International Space Station (ISS), it can take 6 to 24 hours to reliably catalog a newly disposed upper stage and up to 33 hours to plan and execute an avoidance maneuver. This creates a gap in the existing collision risk protection for newly launched vehicles, which covers the period when these launched objects are still under propulsive control; specifically, upper stage separation plus 100 minutes for most missions. This gap results in a vulnerability of the ISS from the end of current "Launch Collision Avoidance (COLA)" protection until approximately launch plus 56 hours.In order to help mitigate this gap, conjunction analyses are being developed that identify launch times when the disposed upper stage could violate safe separation distances from the ISS. Launch window cut-out times can be determined from the analysis and implemented to protect the ISS.The COLA Gap is considered to be a risk to ISS operations and vehicle safety. Methods can be used to mitigate the risk, but the criteria and process need to be established and developed in order to reduce operational disruptions and potential risk to ISS vehicle. New requirements and analytical methods can close the current COLA gap with minimal impact to typical launch windows for Geo-Transfer Orbit (GTO) and direct injection missions. Also, strategies can be established to produce common standards in the U.S. and the world to close the current Launch COLA gap.

Telerobot local-remote control architecture for space flight program applications

NASA Technical Reports Server (NTRS)

Zimmerman, Wayne; Backes, Paul; Steele, Robert; Long, Mark; Bon, Bruce; Beahan, John

1993-01-01

The JPL Supervisory Telerobotics (STELER) Laboratory has developed and demonstrated a unique local-remote robot control architecture which enables management of intermittent communication bus latencies and delays such as those expected for ground-remote operation of Space Station robotic systems via the Tracking and Data Relay Satellite System (TDRSS) communication platform. The current work at JPL in this area has focused on enhancing the technologies and transferring the control architecture to hardware and software environments which are more compatible with projected ground and space operational environments. At the local site, the operator updates the remote worksite model using stereo video and a model overlay/fitting algorithm which outputs the location and orientation of the object in free space. That information is relayed to the robot User Macro Interface (UMI) to enable programming of the robot control macros. This capability runs on a single Silicon Graphics Inc. machine. The operator can employ either manual teleoperation, shared control, or supervised autonomous control to manipulate the intended object. The remote site controller, called the Modular Telerobot Task Execution System (MOTES), runs in a multi-processor VME environment and performs the task sequencing, task execution, trajectory generation, closed loop force/torque control, task parameter monitoring, and reflex action. This paper describes the new STELER architecture implementation, and also documents the results of the recent autonomous docking task execution using the local site and MOTES.

Human-telerobot interactions - Information, control, and mental models

NASA Technical Reports Server (NTRS)

Smith, Randy L.; Gillan, Douglas J.

1987-01-01

A part of the NASA's Space Station will be a teleoperated robot (telerobot) with arms for grasping and manipulation, feet for holding onto objects, and television cameras for visual feedback. The objective of the work described in this paper is to develop the requirements and specifications for the user-telerobot interface and to determine through research and testing that the interface results in efficient system operation. The focus of the development of the user-telerobot interface is on the information required by the user, the user inputs, and the design of the control workstation. Closely related to both the information required by the user and the user's control of the telerobot is the user's mental model of the relationship between the control inputs and the telerobot's actions.

Close-Spaced High Temperature Knudsen Flow.

DTIC Science & Technology

1986-07-15

work~was a study of discharge processes in Knudsen mode (collisionless), thermionic energy converters. Areas of research involve’mechanisms for reducing ...power densities. The mechanisms/we have chosen to study are: reduction of space-charge through a very close interelectrode gap (less than 10 microns...In order to operate at practical current densities, the effect of electron space charge must be reduced . This can be done through very close

Motion compensation for robotic lung tumour radiotherapy in remote locations: A personalised medicine approach

NASA Astrophysics Data System (ADS)

Ionescu, Clara M.; Copot, Cosmin; Verellen, Dirk

2017-03-01

The purpose of this work is to integrate the concept of patient-in-the-closed-loop application with tumour treatment of cancer-diagnosed patients in remote areas. The generic closed loop control objective is effective synchronisation of the radiation focus to the movement of a lung tissue tumour during actual breathing of the patient. This is facilitated by accurate repositioning of a robotic arm manipulator, i.e. we emulate the Cyberknife Robotic Radiosurgery system. Predictive control with disturbance filter is used in this application in a minimalistic model design. Performance of the control structure is validated by means of simulation using real recorded breathing patterns from patients measured in 3D space. Latency in communication protocol is taken into account, given telerobotics involve autonomous operation of a robot interacting with a human being in different location. Our results suggest that the proposed closed loop control structure has practical potential to individualise the treatment and improves accuracy by at least 15%.

Dwarf Wheat grown aboard the International Space Station

NASA Technical Reports Server (NTRS)

2003-01-01

Dwarf wheat were photographed aboard the International Space Station in April 2002. Lessons from on-orbit research on plants will have applications to terrestrial agriculture as well as for long-term space missions. Alternative agricultural systems that can efficiently produce greater quantities of high-quality crops in a small area are important for future space expeditions. Also regenerative life-support systems that include plants will be an important component of long-term space missions. Data from the Biomass Production System (BPS) and the Photosynthesis Experiment and System Testing and Operations (PESTO) will advance controlled-environment agricultural systems and will help farmers produce better, healthier crops in a small area. This same knowledge is critical to closed-loop life support systems for spacecraft. The BPS comprises a miniature environmental control system for four plant growth chambers, all in the volume of two space shuttle lockers. The experience with the BPS on orbit is providing valuable design and operational lessons that will be incorporated into the Plant Growth Units. The objective of PESTO was to flight verify the BPS hardware and to determine how the microgravity environment affects the photosynthesis and metabolic function of Super Dwarf wheat and Brassica rapa (a member of the mustard family).

Three near term commercial markets in space and their potential role in space exploration

NASA Astrophysics Data System (ADS)

Gavert, Raymond B.

2001-02-01

Independent market studies related to Low Earth Orbit (LEO) commercialization have identified three near term markets that have return-on-investment potential. These markets are: (1) Entertainment (2) Education (3) Advertising/sponsorship. Commercial activity is presently underway focusing on these areas. A private company is working with the Russians on a commercial module attached to the ISS that will involve entertainment and probably the other two activities as well. A separate corporation has been established to commercialize the Russian Mir Space Station with entertainment and promotional advertising as important revenue sources. A new startup company has signed an agreement with NASA for commercial media activity on the International Space Station (ISS). Profit making education programs are being developed by a private firm to allow students to play the role of an astronaut and work closely with space scientists and astronauts. It is expected that the success of these efforts on the ISS program will extend to exploration missions beyond LEO. The objective of this paper is to extrapolate some of the LEO commercialization experiences to see what might be expected in space exploration missions to Mars, the Moon and beyond. .

TacSat-2: Path finder for a Close Space Support Asset

NASA Astrophysics Data System (ADS)

Bhopale, A.; Finley, C.

2008-08-01

With th e launch of TacSat-2, the Oper ationally Responsive Sp ace (O RS) commun ity had its f irst on- orbit asset and opportunity to prove or disprove the premise that small, in expensiv e, and quickly constructed spacecraf t could perform useful operation al missions when needed and for as long as need ed. All of the components of the comp lex TacSat-2 system had to work together to answer the basic questions, "In a crisis, can a lab-developed spacecraf t and ground architecture competen tly p erform th e mission of systems that cost twen ty times the price and tak e four times as long to develop? Mor eover, can th is system actu ally improve on the responsiveness of Nation al Systems to a certain set of underserv ed Oper ational customers?" When all w as said and done, TacSat-2 was a sp acecraf t that h ad to: 1) Carry th irteen tactical and scientific payloads to orbit, many of which doubled as essen tial, non-redundant subsystems; 2) Launch from an unproven launch base on a last minute "rep lacement" launch vehicle; and 3) Fulfill about 140 on-orbit mission requirements. It had tactical sensors, two unproven communication links, numerous next-gen eration single- string componen ts (e.g., h igh-efficiency propulsion system, thin-film so lar arrays, low-power versatile star camera) , and autonomous softw are to mak e the system more friendly and familiar to Tactical, rather than Spacecraf t Op erators. However, the mission was as mu ch about the implementation as it w as about the components. TacSat-2 was designed for and emp loyed with a different concept of operations ( CONOPS) than tradition al N ational Operational Assets. It w as designed to be th e fir st-ev er Clo se Space Support platform and operated in a manner more analogous to Close Air Support aircraf t than to tr aditional spacecraft. Therefore, th e primary objective of the TacSat-2 mission was to use th e TacSat-2 system to id entify those parts of the spacecr aft, ground system, and CON OPS that mak e it eff ectiv e and su itable for a Tactical Operator emp loying it as a Close Space Support asset. The TacSat-2 story was tru ly a story of survival in the low-budget, high-expectation spacecraft world . The mission su ccesses w ere signif icant and ground- breaking, but they w ere, almost w ithou t exception, compromised successes. Most importan tly, you w ill see an asset th at was unquestionably bo th effective and suitable for military operators, but only worth the investmen t if curren t responsiveness deficiencies dr ive leadership towards a so lution where Close Space Support platforms are a pursued alternativ e. This p aper w ill present the objective positive and negative r esults of the TacSat-2 system' s space/ground components and CONO PS and w ill use these resu lts to project th e co mplexion of an OpSat-X that could best fulfill the role of a Close Sp ace Support p latform directly employed by a front-lin e tactical oper ator to responsively return a product that meets an immediate need.

In-vivo force decay of nickel-titanium closed-coil springs.

PubMed

Cox, Crystal; Nguyen, Tung; Koroluk, Lorne; Ko, Ching-Chang

2014-04-01

Nickel-titanium closed-coil springs are purported to deliver constant forces over extended ranges of activation and working times. In-vivo studies supporting this claim are limited. The objective of this study was to evaluate changes in force-decay properties of nickel-titanium closed-coil springs after clinical use. Pseudoelastic force-deflection curves for 30 nickel-titanium coil springs (used intraorally) and 15 matched laboratory control springs (simulated intraoral conditions: artificial saliva, 37°C) were tested before and after retrieval via dynamic mechanical analysis and a testing machine, respectively, to evaluate the amounts of force-loss and hysteresis change after 4, 8, or 12 weeks of working time (n = 10 per group). The effects of the oral environment and clinical use on force properties were evaluated by comparing in-vivo and in-vitro data. The springs studied showed a statistically significant decrease in force (approximately 12%) after 4 weeks of clinical use (P <0.01), with a further significant decrease (approximately 7%) from 4 to 8 weeks (P = 0.03), and force levels appearing to remain steady thereafter. Clinical space closure at an average rate of 0.91 mm per month was still observed despite this decrease in force. In-vivo and in-vitro force-loss data were not statistically different. Nickel-titanium closed-coil springs do not deliver constant forces when used intraorally, but they still allow for space-closure rates of approximately 1 mm per month. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Rationale for evaluating a closed food chain for space habitats

NASA Technical Reports Server (NTRS)

Modell, M.; Spurlock, J. M.

1980-01-01

Closed food cycles for long duration space flight and space habitation are examined. Wash water for a crew of six is economically recyclable after a week, while a total closed loop water system is effective only if the stay exceeds six months' length. The stoichiometry of net plant growth is calculated and it is shown that the return of urine, feces, and inedible plant parts to the food chain, along with the addition of photosynthesis, closes the food chain loop. Scenarios are presented to explore the technical feasibility of achieving a closed loop system. An optimal choice of plants is followed by processing, waste conversion, equipment specifications, and control requirements, and finally, cost-effectiveness.

A Tracker for Broken and Closely-Spaced Lines

DTIC Science & Technology

1997-10-01

to combine the current level flow estimate and the previous level flow estimate. However, the result is still not good enough for some reasons. First...geometric attributes are not good enough to discriminate line segments, when they are crowded, parallel and closely-spaced to each other. On the other...level information [10]. Still, it is not good at dealing with closely-spaced line segments. Because it requires a proper size of square neighborhood to

Close up oblique view aft, port side of the Orbiter ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Close up oblique view aft, port side of the Orbiter Discovery in the Vehicle Assembly Building at NASA's Kennedy Space Center. This view shows a close up of the elevons and underside of the port wing. On the aft fuselage in the approximate center rift of the image is the T-0 umbilical panels. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

Noise kernels of stochastic gravity in conformally-flat spacetimes

NASA Astrophysics Data System (ADS)

Cho, H. T.; Hu, B. L.

2015-03-01

The central object in the theory of semiclassical stochastic gravity is the noise kernel, which is the symmetric two point correlation function of the stress-energy tensor. Using the corresponding Wightman functions in Minkowski, Einstein and open Einstein spaces, we construct the noise kernels of a conformally coupled scalar field in these spacetimes. From them we show that the noise kernels in conformally-flat spacetimes, including the Friedmann-Robertson-Walker universes, can be obtained in closed analytic forms by using a combination of conformal and coordinate transformations.

Late-Notice HIE Investigation

NASA Technical Reports Server (NTRS)

Hejduk, M. D.

2016-01-01

Provide a response to MOWG action item 1410-01: Analyze close approaches which have required mission team action on short notice. Determine why the approaches were identified later in the process than most other events. Method: Performed an analysis to determine whether there is any correlation between late notice event identification and space weather, sparse tracking, or high drag objects, which would allow preventive action to be taken Examined specific late notice events identified by missions as problematic to try to identify root cause and attempt to relate them to the correlation analysis.

[Mechanisms of indeterminacy between the imaginary and the rational worlds in schizophrenic subjects].

PubMed

Gauthier, J-M; Widart, F

2008-09-01

Our investigation into dream and delirium in schizophrenic subjects was based on the notion of magical thought developed by Sami-Ali. Starting from this notion, we attempted to determine whether they somehow differentiate the psychic space of dream from that of delirium, whether either of these two spaces, or both, are caught in a relational deadlock, and eventually to analyse the quality of the relationship to others. The underlying assumption is that magical thought is foregrounded in the psychic life of schizophrenic subjects, and that these subjects do not distinguish between the psychic spaces of dream and delirium, nor between the world, others, and themselves. Results show first that the prevalence of magical thought has the following consequences: (a) features characterizing space are those of an imaginary space, i.e. internal and external realities are blurred, what is outside is reflected inside, and vice versa, the subject-object distinction is cancelled to leave one single reality that ignores contradiction; (b) the time of discourse is an imaginary time: their discourses express past and future as belonging to an absolute "perpetual" present. Events they mention are experienced as contemporary. Causal relations, being imaginary, can be reversed. However, some socially sanctioned landmarks in time are often maintained. These are rarely related to any event in their own emotional lives. Second, our results provide evidence for some permeability between the space of dream and the space of delirium. Yet, this permeability can vary from one subject to another. Third, they show that relational deadlocks recur regularly, though not systematically, in the lives of our subjects. Relational deadlocks in dreams are not easy to detect. Finally, the kind of relationship those people have to others is quite paradoxical: physical closeness results in emotional distance, and conversely emotional closeness is only possible in physical distance. The others cannot really exist in the relationship; they are a horizon towards which those people yearn without ever being able to reach it. This kind of paradox, of relational deadlock, may be the ground on which psychosis thrives: it is impossible to be close to the nonself, while it is also deeply wished for. Even the logic of imaginary space - in which everything should be possible - cannot help overcome this paradox. And - a paradox within the paradox - this logic still comes upon a deadline in the potentially infinite and indefinite space it produces. This boundary could be the deadlock that cannot and yet must be overcome, a deadlock that would endlessly fuel the patients' delirium.

A New NASA Book: Touch the Sun

NASA Astrophysics Data System (ADS)

Grice, N. A.

2005-05-01

People who are blind or visually impaired rely partly on their sense of touch to help paint pictures of objects and places in their mind's eye; however, astronomy and space science are, by nature, generally inaccessible to the touch. The universe, as seen by the Hubble Space Telescope, was made hands-on in 2002 with the publication of Touch the Universe: A NASA Braille Book of Astronomy. This year, the Sun becomes an accessible object in a new universally designed publication called Touch the Sun. Touch the Sun contains text pages with both print and Braille. It features colorful embossed images from the Solar and Heliospheric Observatory (SOHO) and the Transition Region and Coronal Explorer (TRACE) spacecraft. There is also a close-up picture of a sunspot from the National Solar Observatory at Sacramento Peak. Textures of swirling gas currents, dark sunspots, curving magnetic fields and explosive eruptions emphasize the dynamic nature of the Sun. The prototype images were tested with students from the Colorado School for the Deaf and Blind; the images were revised, based upon their evaluations. Drs. Joe Gurman and Steele Hill from the Goddard Space Flight Center served as scientific consultants. Learn more about this special resource and try out some of the tactile images yourself!

The COLA Collision Avoidance Method

NASA Astrophysics Data System (ADS)

Assmann, K.; Berger, J.; Grothkopp, S.

2009-03-01

In the following we present a collision avoidance method named COLA. The method has been designed to predict collisions for Earth orbiting spacecraft on any orbits, including orbit changes, with other space-born objects. The point in time of a collision and the collision probability are determined. To guarantee effective processing the COLA method uses a modular design and is composed of several components which are either developed within this work or deduced from existing algorithms: A filtering module, the close approach determination, the collision detection and the collision probability calculation. A software tool which implements the COLA method has been verified using various test cases built from sample missions. This software has been implemented in the C++ programming language and serves as a universal collision detection tool at LSE Space Engineering & Operations AG.

Accreting Double White Dwarf Binaries: Implications for LISA

NASA Astrophysics Data System (ADS)

Kremer, Kyle; Breivik, Katelyn; Larson, Shane L.; Kalogera, Vassiliki

2017-09-01

We explore the long-term evolution of mass-transferring white dwarf (WD) binaries undergoing both direct-impact and disk accretion and explore implications of such systems to gravitational-wave (GW) astronomy. We cover a broad range of initial component masses and show that these systems, the majority of which lie within the Laser Interferometer Space Antenna (LISA) sensitivity range, exhibit prominent negative orbital frequency evolution (chirp) for a significant fraction of their lifetimes. Using a galactic population synthesis, we predict ˜2700 of these systems will be observable with a negative chirp of 0.1 yr-2 by a space-based GW detector like LISA. We also show that detections of mass-transferring double WD systems by LISA may provide astronomers with unique ways of probing the physics governing close compact object binaries.

Rational, computer-enabled peptide drug design: principles, methods, applications and future directions.

PubMed

Diller, David J; Swanson, Jon; Bayden, Alexander S; Jarosinski, Mark; Audie, Joseph

2015-01-01

Peptides provide promising templates for developing drugs to occupy a middle space between small molecules and antibodies and for targeting 'undruggable' intracellular protein-protein interactions. Importantly, rational or in cerebro design, especially when coupled with validated in silico tools, can be used to efficiently explore chemical space and identify islands of 'drug-like' peptides to satisfy diverse drug discovery program objectives. Here, we consider the underlying principles of and recent advances in rational, computer-enabled peptide drug design. In particular, we consider the impact of basic physicochemical properties, potency and ADME/Tox opportunities and challenges, and recently developed computational tools for enabling rational peptide drug design. Key principles and practices are spotlighted by recent case studies. We close with a hypothetical future case study.

Space Shuttle SRM development. [Solid Rocket Motors

NASA Technical Reports Server (NTRS)

Brinton, B. C.; Kilminster, J. C.

1979-01-01

The successful static test of the fourth Development Space Shuttle Solid Rocket Motor (SRM) in February 1979 concluded the development testing phase of the SRM Project. Qualification and flight motors are currently being fabricated, with the first qualification motor to be static tested. Delivered thrust-time traces on all development motors were very close to predicted values, and both specific and total impulse exceeded specification requirements. 'All-up' static tests conducted with a solid rocket booster equipment on development motors achieved all test objectives. Transportation and support equipment concepts have been proven, baselining is complete, and component reusability has been demonstrated. Evolution of the SRM transportation support equipment, and special test equipment designs are reviewed, and development activities discussed. Handling and processing aspects of large, heavy components are described.

Temporal models for the episodic volcanism of Campi Flegrei caldera (Italy) with uncertainty quantification

NASA Astrophysics Data System (ADS)

Bevilacqua, Andrea; Flandoli, Franco; Neri, Augusto; Isaia, Roberto; Vitale, Stefano

2016-11-01

After the large-scale event of Neapolitan Yellow Tuff ( 15 ka B.P.), intense and mostly explosive volcanism has occurred within and along the boundaries of the Campi Flegrei caldera (Italy). Eruptions occurred closely spaced in time, over periods from a few centuries to a few millennia, and were alternated with periods of quiescence lasting up to several millennia. Often events also occurred closely in space, thus generating a cluster of events. This study had two main objectives: (1) to describe the uncertainty in the geologic record by using a quantitative model and (2) to develop, based on the uncertainty assessment, a long-term subdomain specific temporal probability model that describes the temporal and spatial eruptive behavior of the caldera. In particular, the study adopts a space-time doubly stochastic nonhomogeneous Poisson-type model with a local self-excitation feature able to generate clustering of events which are consistent with the reconstructed record of Campi Flegrei. Results allow the evaluation of similarities and differences between the three epochs of activity as well as to derive eruptive base rate of the caldera and its capacity to generate clusters of events. The temporal probability model is also used to investigate the effect of the most recent eruption of Monte Nuovo (A.D. 1538) in a possible reactivation of the caldera and to estimate the time to the next eruption under different volcanological and modeling assumptions.

Megawatt Class Nuclear Space Power Systems (MCNSPS) conceptual design and evaluation report. Volume 1: Objectives, summary results and introduction

NASA Technical Reports Server (NTRS)

Wetch, J. R.

1988-01-01

The objective was to determine which reactor, conversion, and radiator technologies would best fulfill future Megawatt Class Nuclear Space Power System Requirements. Specifically, the requirement was 10 megawatts for 5 years of full power operation and 10 years systems life on orbit. A variety of liquid metal and gas cooled reactors, static and dynamic conversion systems, and passive and dynamic radiators were considered. Four concepts were selected for more detailed study. The concepts are: a gas cooled reactor with closed cycle Brayton turbine-alternator conversion with heat pipe and pumped tube-fin heat rejection; a lithium cooled reactor with a free piston Stirling engine-linear alternator and a pumped tube-fin radiator; a lithium cooled reactor with potassium Rankine turbine-alternator and heat pipe radiator; and a lithium cooled incore thermionic static conversion reactor with a heat pipe radiator. The systems recommended for further development to meet a 10 megawatt long life requirement are the lithium cooled reactor with the K-Rankine conversion and heat pipe radiator, and the lithium cooled incore thermionic reactor with heat pipe radiator.

KSC-99pp0709

NASA Image and Video Library

1999-06-18

Inside the Vertical Processing Facility, doors on the payload canister begin to close on the Chandra X-ray Observatory inside before being moved to Launch Pad 39B. Liftoff will take place no earlier than July 20 at 12:36 a.m. EDT aboard Space Shuttle Columbia, on mission STS-93. Chandra will allow scientists from around the world to obtain unprecedented X-ray images of exotic environments to help understand the structure and evolution of the universe. Chandra is expected to provide unique and crucial information on the nature of objects ranging from comets in our solar system to quasars at the edge of the observable universe, map the location of dark matter and help to identify it, and probe the faintest of active galaxies, allowing scientists to study not only how their energy output changes with time, but also how these objects produce their intense energy emissions in the first place. Since X-rays are absorbed by the Earth's atmosphere, space-based observatories are necessary to study these phenomena and allow scientists to analyze some of the greatest mysteries of the universe

RL-34 ring laser gyro laboratory evaluation for the Deep Space Network antenna application

NASA Technical Reports Server (NTRS)

1991-01-01

The overall results of this laboratory evaluation are quite encouraging. The gyro data is in good agreement with the system's overall pointing performance, which is quite close to the technical objectives for the Deep Space Network (DSN) application. The system can be calibrated to the levels required for millidegree levels of pointing performance, and initialization performance is within the required 0.001 degree objective. The blind target acquisition performance is within a factor of two of the 0.0001 degree objective, limited only by a combination of the slow rate (0.5 deg/sec) and the existing production quantization logic (0.38 arc-sec/pulse). Logic circuitry exists to better this performance such that it will better the objective by 50 percent. Representative data with this circuitry has been provided for illustration. Target tracking performance is about twice the one millidegree objective, with several factors contributing. The first factor is the bias stability of the gyros, which is exceptional, but will limit performance to the 0.001 and 0.002 degree range for long tracking periods. The second contributing factor is the accelerometer contributions when the system is elevated. These degrade performance into the 0.003 to 0.004 degree range, which could be improved upon with some additional changes. Finally, we have provided a set of recommendations to improve performance closer to the technical objectives. These recommendations include gyro, electronics, and system configurational changes that form the basis for additional work to achieve the desired performance. In conclusion, we believe that the RL-34 ring laser gyro-based advanced navigation system demonstrated performance consistent with expectations and technical objectives, and it has the potential for even further enhancement for the DSN application.

Models of Wake-Vortex Spreading Mechanisms and Their Estimated Uncertainties

NASA Technical Reports Server (NTRS)

Rossow, Vernon J.; Hardy, Gordon H.; Meyn, Larry A.

2006-01-01

One of the primary constraints on the capacity of the nation's air transportation system is the landing capacity at its busiest airports. Many airports with nearly-simultaneous operations on closely-spaced parallel runways (i.e., as close as 750 ft (246m)) suffer a severe decrease in runway acceptance rate when weather conditions do not allow full utilization. The objective of a research program at NASA Ames Research Center is to develop the technologies needed for traffic management in the airport environment so that operations now allowed on closely-spaced parallel runways under Visual Meteorological Conditions can also be carried out under Instrument Meteorological Conditions. As part of this overall research objective, the study reported here has developed improved models for the various aerodynamic mechanisms that spread and transport wake vortices. The purpose of the study is to continue the development of relationships that increase the accuracy of estimates for the along-trail separation distances available before the vortex wake of a leading aircraft intrudes into the airspace of a following aircraft. Details of the models used and their uncertainties are presented in the appendices to the paper. Suggestions are made as to the theoretical and experimental research needed to increase the accuracy of and confidence level in the models presented and instrumentation required or more precise estimates of the motion and spread of vortex wakes. The improved wake models indicate that, if the following aircraft is upwind of the leading aircraft, the vortex wakes of the leading aircraft will not intrude into the airspace of the following aircraft for about 7s (based on pessimistic assumptions) for most atmospheric conditions. The wake-spreading models also indicate that longer time intervals before wake intrusion are available when atmospheric turbulence levels are mild or moderate. However, if the estimates for those time intervals are to be reliable, further study is necessary to develop the instrumentation and procedures needed to accurately define when the more benign atmospheric conditions exist.

Magellan attitude and articulation control subsystem closed loop testing

NASA Technical Reports Server (NTRS)

Olschansky, David G.

1987-01-01

In the spring of 1989, the Magellan spacecraft will embark on a two-year mission to map the surface of the planet Venus. Guiding it there will be the Attitude and Articulation Control Subsystem (AACS). To ensure reliable operations the AACS is being put through a rigorous test program at Martin Marietta Denver Aerospace. Before Magellan ever leaves the Space Shuttle bay from which it is to be launched, its components will have flown a simulated spaceflight in a ground-based lab. The primary objectives of the test program are to verify form, fit, and function of the AACS, particularly subsystem external interfaces and functional operation of the flight software. This paper discusses the Magellan Closed Loop Test Systems which makes realistic tests possible by simulating the dynamic and 'visual' flight environment for AACS components in the lab.

Convex set and linear mixing model

NASA Technical Reports Server (NTRS)

Xu, P.; Greeley, R.

1993-01-01

A major goal of optical remote sensing is to determine surface compositions of the earth and other planetary objects. For assessment of composition, single pixels in multi-spectral images usually record a mixture of the signals from various materials within the corresponding surface area. In this report, we introduce a closed and bounded convex set as a mathematical model for linear mixing. This model has a clear geometric implication because the closed and bounded convex set is a natural generalization of a triangle in n-space. The endmembers are extreme points of the convex set. Every point in the convex closure of the endmembers is a linear mixture of those endmembers, which is exactly how linear mixing is defined. With this model, some general criteria for selecting endmembers could be described. This model can lead to a better understanding of linear mixing models.

Modal vector estimation for closely spaced frequency modes

NASA Technical Reports Server (NTRS)

Craig, R. R., Jr.; Chung, Y. T.; Blair, M.

1982-01-01

Techniques for obtaining improved modal vector estimates for systems with closely spaced frequency modes are discussed. In describing the dynamical behavior of a complex structure modal parameters are often analyzed: undamped natural frequency, mode shape, modal mass, modal stiffness and modal damping. From both an analytical standpoint and an experimental standpoint, identification of modal parameters is more difficult if the system has repeated frequencies or even closely spaced frequencies. The more complex the structure, the more likely it is to have closely spaced frequencies. This makes it difficult to determine valid mode shapes using single shaker test methods. By employing band selectable analysis (zoom) techniques and by employing Kennedy-Pancu circle fitting or some multiple degree of freedom (MDOF) curve fit procedure, the usefulness of the single shaker approach can be extended.

Dynamics modelling and Hybrid Suppression Control of space robots performing cooperative object manipulation

NASA Astrophysics Data System (ADS)

Zarafshan, P.; Moosavian, S. Ali A.

2013-10-01

Dynamics modelling and control of multi-body space robotic systems composed of rigid and flexible elements is elaborated here. Control of such systems is highly complicated due to severe under-actuated condition caused by flexible elements, and an inherent uneven nonlinear dynamics. Therefore, developing a compact dynamics model with the requirement of limited computations is extremely useful for controller design, also to develop simulation studies in support of design improvement, and finally for practical implementations. In this paper, the Rigid-Flexible Interactive dynamics Modelling (RFIM) approach is introduced as a combination of Lagrange and Newton-Euler methods, in which the motion equations of rigid and flexible members are separately developed in an explicit closed form. These equations are then assembled and solved simultaneously at each time step by considering the mutual interaction and constraint forces. The proposed approach yields a compact model rather than common accumulation approach that leads to a massive set of equations in which the dynamics of flexible elements is united with the dynamics equations of rigid members. To reveal such merits of this new approach, a Hybrid Suppression Control (HSC) for a cooperative object manipulation task will be proposed, and applied to usual space systems. A Wheeled Mobile Robotic (WMR) system with flexible appendages as a typical space rover is considered which contains a rigid main body equipped with two manipulating arms and two flexible solar panels, and next a Space Free Flying Robotic system (SFFR) with flexible members is studied. Modelling verification of these complicated systems is vigorously performed using ANSYS and ADAMS programs, while the limited computations of RFIM approach provides an efficient tool for the proposed controller design. Furthermore, it will be shown that the vibrations of the flexible solar panels results in disturbing forces on the base which may produce undesirable errors and perturb the object manipulation task. So, it is shown that these effects can be significantly eliminated by the proposed Hybrid Suppression Control algorithm.

Improved Space Object Orbit Determination Using CMOS Detectors

NASA Astrophysics Data System (ADS)

Schildknecht, T.; Peltonen, J.; Sännti, T.; Silha, J.; Flohrer, T.

2014-09-01

CMOS-sensors, or in general Active Pixel Sensors (APS), are rapidly replacing CCDs in the consumer camera market. Due to significant technological advances during the past years these devices start to compete with CCDs also for demanding scientific imaging applications, in particular in the astronomy community. CMOS detectors offer a series of inherent advantages compared to CCDs, due to the structure of their basic pixel cells, which each contains their own amplifier and readout electronics. The most prominent advantages for space object observations are the extremely fast and flexible readout capabilities, feasibility for electronic shuttering and precise epoch registration, and the potential to perform image processing operations on-chip and in real-time. The major challenges and design drivers for ground-based and space-based optical observation strategies have been analyzed. CMOS detector characteristics were critically evaluated and compared with the established CCD technology, especially with respect to the above mentioned observations. Similarly, the desirable on-chip processing functionalities which would further enhance the object detection and image segmentation were identified. Finally, we simulated several observation scenarios for ground- and space-based sensor by assuming different observation and sensor properties. We will introduce the analyzed end-to-end simulations of the ground- and space-based strategies in order to investigate the orbit determination accuracy and its sensitivity which may result from different values for the frame-rate, pixel scale, astrometric and epoch registration accuracies. Two cases were simulated, a survey using a ground-based sensor to observe objects in LEO for surveillance applications, and a statistical survey with a space-based sensor orbiting in LEO observing small-size debris in LEO. The ground-based LEO survey uses a dynamical fence close to the Earth shadow a few hours after sunset. For the space-based scenario a sensor in a sun-synchronous LEO orbit, always pointing in the anti-sun direction to achieve optimum illumination conditions for small LEO debris, was simulated. For the space-based scenario the simulations showed a 20 130 % improvement of the accuracy of all orbital parameters when varying the frame rate from 1/3 fps, which is the fastest rate for a typical CCD detector, to 50 fps, which represents the highest rate of scientific CMOS cameras. Changing the epoch registration accuracy from a typical 20.0 ms for a mechanical shutter to 0.025 ms, the theoretical value for the electronic shutter of a CMOS camera, improved the orbit accuracy by 4 to 190 %. The ground-based scenario also benefit from the specific CMOS characteristics, but to a lesser extent.

On the Essence of Space

NASA Astrophysics Data System (ADS)

Kalanov, Temur Z.

2003-04-01

A new theory of space is suggested. It represents the new point of view which has arisen from the critical analysis of the foundations of physics (in particular the theory of relativity and quantum mechanics), mathematics, cosmology and philosophy. The main idea following from the analysis is that the concept of movement represents a key to understanding of the essence of space. The starting-point of the theory is represented by the following philosophical (dialectical materialistic) principles. (a) The principle of the materiality (of the objective reality) of the Nature: the Nature (the Universe) is a system (a set) of material objects (particles, bodies, fields); each object has properties, features, and the properties, the features are inseparable characteristics of material object and belong only to material object. (b) The principle of the existence of material object: an object exists as the objective reality, and movement is a form of existence of object. (c) The principle (definition) of movement of object: the movement is change (i.e. transition of some states into others) in general; the movement determines a direction, and direction characterizes the movement. (d) The principle of existence of time: the time exists as the parameter of the system of reference. These principles lead to the following statements expressing the essence of space. (1) There is no space in general, and there exist space only as a form of existence of the properties and features of the object. It means that the space is a set of the measures of the object (the measure is the philosophical category meaning unity of the qualitative and quantitative determinacy of the object). In other words, the space of the object is a set of the states of the object. (2) The states of the object are manifested only in a system of reference. The main informational property of the unitary system researched physical object + system of reference is that the system of reference determines (measures, calculates) the parameters of the subsystem researched physical object (for example, the coordinates of the object M); the parameters characterize the system of reference (for example, the system of coordinates S). (3) Each parameter of the object is its measure. Total number of the mutually independent parameters of the object is called dimension of the space of the object. (4) The set of numerical values (i.e. the range, the spectrum) of each parameter is the subspace of the object. (The coordinate space, the momentum space and the energy space are examples of the subspaces of the object). (5) The set of the parameters of the object is divided into two non intersecting (opposite) classes: the class of the internal parameters and the class of the non internal (i.e. external) parameters. The class of the external parameters is divided into two non intersecting (opposite) subclasses: the subclass of the absolute parameters (characterizing the form, the sizes of the object) and the subclass of the non absolute (relative) parameters (characterizing the position, the coordinates of the object). (6) Set of the external parameters forms the external space of object. It is called geometrical space of object. (7) Since a macroscopic object has three mutually independent sizes, the dimension of its external absolute space is equal to three. Consequently, the dimension of its external relative space is also equal to three. Thus, the total dimension of the external space of the macroscopic object is equal to six. (8) In general case, the external absolute space (i.e. the form, the sizes) and the external relative space (i.e. the position, the coordinates) of any object are mutually dependent because of influence of a medium. The geometrical space of such object is called non Euclidean space. If the external absolute space and the external relative space of some object are mutually independent, then the external relative space of such object is the homogeneous and isotropic geometrical space. It is called Euclidean space of the object. Consequences: (i) the question of true geometry of the Universe is incorrect; (ii) the theory of relativity has no physical meaning.

Kuipers closes hatch

NASA Image and Video Library

2012-03-24

ISS030-E-173931 (24 March 2012) --- European Space Agency astronaut Andre Kuipers, Expedition 30 flight engineer, closes a hatch in the International Space Station as crew members prepare to move to the appropriate Soyuz vehicles, due to the possibility that space debris could pass close to the station. Burbank, Shkaplerov and Ivanishin sheltered in the Soyuz TMA-22 spacecraft attached to the Poisk Mini-Research Module 2 (MRM2) while Kononenko, Kuipers and Pettit took to the Soyuz TMA-03M docked to the Rassvet Mini-Research Module 1 (MRM-1).

Close-Spaced High Temperature Knudsen Flow.

DTIC Science & Technology

1984-06-15

study of discharge processes in Knudsen mode (collisionless), thermionic energy converters. Areas of research involve mechanism for reducing the...The mechanisms we have chosen to study are: reduction of space-charge through a very close inter- electrode gap (less than 10 microns); transport and...AD-AI4U 471 :NNTIM R~ A Rl M ,i; ,11 , i J)W R8 1070 1 I~ "i E~Hhhh IIt Ll ~ : RASOR ASSOCIATES, INC.- AFOSR.TR. 84-1070 NSR-22-2 CLOSE -SPACED HIGH

Exploring Space on the Computer

NASA Technical Reports Server (NTRS)

Bozym, Patrick

2004-01-01

For the past year Dennis Stocker has been in the process of developing pencil and paper games, which are fun, challenging, and educational for middle school and high school students. The latest version of these pencil and paper games is Spaceship Commander. The objective of the game is to earn points by plotting the flight path of a spaceship so astronauts can perform microgravity experiments, and make short-range measurements of other planets. During my ten weeks here at the GRC my goal is to create a computer based version of Spaceship commander. During the development of this game the primary focus has been on making it as educational and fun for the student as possible. The main educational objective of this game is to give students an understanding of forces and motion, including gravity. This is done by incorporating Newton's laws into the game. For example a spacecraft in the video game experiences a gravitational force applied to it by planets. The software I am using to create this game is a freeware application called Game Maker. Game Maker allows novice computer programmers like me to create arcade style games using a visual drag and drop interface. By using functions provided by Game Maker and a few I have written myself, I have been able to create a few simple computer games. Currently the computer game allows the student to navigate a space ship around planets, and asteroids by using the arrow keys on the numeric keypad. Each time an arrow key is pressed by the student the corresponding acceleration of the space ship is seen on the screen. Points are earned by navigating the space ship close enough to planets to gather scientific data. However the game encourages the student to plan his or her course carefully, because if the student gets too close to a planet they may not be able to escape the planet s gravity, and crash into the planet. The next step in the game development is to include a launch sequence which allows the student to launch from their home planet at a speed and direction determined by the student. Additional information is included in the original extended abstract.

PIPOR - A Programme for International Polar Oceans Research

NASA Technical Reports Server (NTRS)

Gudmandsen, P.; Carsey, F.; Mcnutt, L.

1989-01-01

The Programme for International Polar Oceans Research is accepted as a part of the ERS-1 mission which will be initiated with the launch of the ERS-1 earth observation satellite by the European Space Agency in 1990. It is a bipolar program with participation by institutions engaged in studies of the atmosphere-ocean-sea ice interaction and the application of remote sensing data for operational uses. The program objectives are to develop the application of microwave data for studies and modeling of sea ice dynamics and for operational uses in sea ice infested areas. As such, it is closely connected with ongoing and forthcoming research in the Arctic and the Antarctic. With sea ice being a sensitive indicator of climate perturbations, PIPOR addresses objectives of the World Climate Research Programme.

NASA Environmental Control and Life Support Technology Development and Maturation for Exploration: 2015 to 2016 Overview

NASA Technical Reports Server (NTRS)

Schneider, Walter F.; Gatens, Robyn L.; Anderson, Molly S.; Broyan, James L.; MaCatangay, Ariel V.; Shull, Sarah A.; Perry, Jay L.; Toomarian, Nikzad

2016-01-01

Over the last year, the National Aeronautics and Space Administration (NASA) has continued to refine the understanding and prioritization of technology gaps that must be closed in order to achieve Evolvable Mars Campaign objectives and near term objectives in the cislunar proving ground. These efforts are reflected in updates to the technical area roadmaps released by NASA in 2015 and have guided technology development and maturation tasks that have been sponsored by various programs. This paper provides an overview of the refined Environmental Control and Life Support (ECLS) strategic planning, as well as a synopsis of key technology and maturation project tasks that occurred in 2014 and early 2015 to support the strategic needs. Plans for the remainder of 2015 and subsequent years are also described.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donnelly, William; Wong, Gabriel

What is the meaning of entanglement in a theory of extended objects such as strings? To address this question we consider the spatial entanglement between two intervals in the Gross-Taylor model, the string theory dual to two-dimensional Yang-Mills theory at large N. The string diagrams that contribute to the entanglement entropy describe open strings with endpoints anchored to the entangling surface, as first argued by Susskind. We develop a canonical theory of these open strings, and describe how closed strings are divided into open strings at the level of the Hilbert space. Here, we derive the modular Hamiltonian for themore » Hartle-Hawking state and show that the corresponding reduced density matrix describes a thermal ensemble of open strings ending on an object at the entangling surface that we call an entanglement brane, or E-brane.« less

Dynamic expansion of alert responses to incoming painful stimuli following tool use.

PubMed

Rossetti, Angela; Romano, Daniele; Bolognini, Nadia; Maravita, Angelo

2015-04-01

Peripersonal space is the region closely surrounding our bodies. Within its boundaries, avoidance of threatening objects is crucial for surviving. Here we explored autonomic responses to painful stimuli with respect to the dynamic properties of the peripersonal space in healthy individuals. To this aim, in a series of experiments, we measured the Skin Conductance Response (SCR) to a noxious stimulus approaching and touching the hand, or stopping at different distances (far, near) from it. Results showed that the anticipatory response to an incoming threat is reduced if the stimulus targets a spatial position far away from the body, as compared to a near or bodily location. However, responses to far stimuli change if the boundaries of reachable space are extended further away by active tool use. Noteworthy, SCR is not influenced by a training consisting of a spatial attention task, without active tool use. This evidence sheds novel light on the adaptive role of peripersonal space, showing its importance for the coding of incoming threatening stimuli and its plasticity induced by contingent experience, such as tool use. Copyright © 2015 Elsevier Ltd. All rights reserved.

Satellite orbital conjunction reports assessing threatening encounters in space (SOCRATES)

NASA Astrophysics Data System (ADS)

Kelso, T. S.; Alfano, S.

2006-05-01

While many satellite operators are aware of the possibility of a collision between their satellite and another object in earth orbit, most seem unaware of the frequency of near misses occurring each day. Until recently, no service existed to advise satellite operators of an impending conjunction of a satellite payload with another satellite, putting the responsibility for determining these occurrences squarely on the satellite operator's shoulders. This problem has been further confounded by the lack of a timely, comprehensive data set of satellite orbital element sets and computationally efficient tools to provide predictions using industry-standard software. As a result, hundreds of conjunctions within 1 km occur each week, with little or no intervention, putting billions of dollars of space hardware at risk, along with their associated missions. As a service to the satellite operator community, the Center for Space Standards & Innovation (CSSI) offers SOCRATES-Satellite Orbital Conjunction Reports Assessing Threatening Encounters in Space. Twice each day, CSSI runs a list of all satellite payloads on orbit against a list of all objects on orbit using the catalog of all unclassified NORAD two-line element sets to look for conjunctions over the next seven days. The runs are made using STK/CAT-Satellite Tool Kit's Conjunction Analysis Tools-together with the NORAD SGP4 propagator in STK. This paper will discuss how SOCRATES works and how it can help satellite operators avoid undesired close approaches through advanced mission planning.

Depth Perception in Space (Artist's Concept)

NASA Technical Reports Server (NTRS)

2007-01-01

This artist's concept shows how astronomers use the unique orbit of NASA's Spitzer Space Telescope and a depth-perceiving trick called parallax to determine the distance of dark planets, black holes and failed stars that lurk invisibly among us. These objects do not produce light, and are too faint to detect from Earth. However, astronomers can deduce their presence from the way they affect the light from background objects. When such a dark body passes in front of a bright star, its gravity warps the path of the star's light and causes it to brighten -- this process is called gravitational microlensing.

By comparing the 'peak brightness' of the microlensing event from two perspectives -- Earth and Spitzer -- scientists can determine how far away the dark object is. Peak brightness is the moment when the observer, the dark object and background star are most closely aligned.

Humans naturally use parallax to determine distance -- this is commonly referred to as depth perception. In the case of humans, each eye sees the position of an object differently. The brain takes each eye's perspective, and instantaneously calculates how far away the object is. In space, astronomers can use the same trick to determine the distance of an invisible dark object.

In this illustration, the dark object is the moving black ball between Earth, Spitzer and our neighboring galaxy the Small Magellanic Cloud (SMC; bottom right).

To determine the object's distance, astronomers observe the microlensing event at its 'peak brightness' from Earth when the dark object crosses our line-of-sight (dashed line) to a given star in the SMC. This represents one perspective, like looking at an object with only your left eye.

To get the other 'right eye' perspective, astronomers also observe the peak brightness with Spitzer when the object later moves through its line-of-sight. Because astronomers know the exact distance between Earth and Spitzer, they can determine the dark body's speed by timing how long it took for Spitzer to see peak brightness after astronomers observed the event on Earth. Using trigonometric equations and graphs to do the 'brain's' job, scientists can infer the dark body's distance.

The scales in this diagram are greatly exaggerated for clarity. The distance between Spitzer and the Earth is miniscule in comparison to the distance to the dark object and SMC. Since microlensing events require extremely precise alignments, even such a tiny separation is enough to measure these objects out to tremendous distances.

Two Visual Pathways in Primates Based on Sampling of Space: Exploitation and Exploration of Visual Information

PubMed Central

Sheth, Bhavin R.; Young, Ryan

2016-01-01

Evidence is strong that the visual pathway is segregated into two distinct streams—ventral and dorsal. Two proposals theorize that the pathways are segregated in function: The ventral stream processes information about object identity, whereas the dorsal stream, according to one model, processes information about either object location, and according to another, is responsible in executing movements under visual control. The models are influential; however recent experimental evidence challenges them, e.g., the ventral stream is not solely responsible for object recognition; conversely, its function is not strictly limited to object vision; the dorsal stream is not responsible by itself for spatial vision or visuomotor control; conversely, its function extends beyond vision or visuomotor control. In their place, we suggest a robust dichotomy consisting of a ventral stream selectively sampling high-resolution/focal spaces, and a dorsal stream sampling nearly all of space with reduced foveal bias. The proposal hews closely to the theme of embodied cognition: Function arises as a consequence of an extant sensory underpinning. A continuous, not sharp, segregation based on function emerges, and carries with it an undercurrent of an exploitation-exploration dichotomy. Under this interpretation, cells of the ventral stream, which individually have more punctate receptive fields that generally include the fovea or parafovea, provide detailed information about object shapes and features and lead to the systematic exploitation of said information; cells of the dorsal stream, which individually have large receptive fields, contribute to visuospatial perception, provide information about the presence/absence of salient objects and their locations for novel exploration and subsequent exploitation by the ventral stream or, under certain conditions, the dorsal stream. We leverage the dichotomy to unify neuropsychological cases under a common umbrella, account for the increased prevalence of multisensory integration in the dorsal stream under a Bayesian framework, predict conditions under which object recognition utilizes the ventral or dorsal stream, and explain why cells of the dorsal stream drive sensorimotor control and motion processing and have poorer feature selectivity. Finally, the model speculates on a dynamic interaction between the two streams that underscores a unified, seamless perception. Existing theories are subsumed under our proposal. PMID:27920670

Two Visual Pathways in Primates Based on Sampling of Space: Exploitation and Exploration of Visual Information.

PubMed

Sheth, Bhavin R; Young, Ryan

2016-01-01

Evidence is strong that the visual pathway is segregated into two distinct streams-ventral and dorsal. Two proposals theorize that the pathways are segregated in function: The ventral stream processes information about object identity, whereas the dorsal stream, according to one model, processes information about either object location, and according to another, is responsible in executing movements under visual control. The models are influential; however recent experimental evidence challenges them, e.g., the ventral stream is not solely responsible for object recognition; conversely, its function is not strictly limited to object vision; the dorsal stream is not responsible by itself for spatial vision or visuomotor control; conversely, its function extends beyond vision or visuomotor control. In their place, we suggest a robust dichotomy consisting of a ventral stream selectively sampling high-resolution/ focal spaces, and a dorsal stream sampling nearly all of space with reduced foveal bias. The proposal hews closely to the theme of embodied cognition: Function arises as a consequence of an extant sensory underpinning. A continuous, not sharp, segregation based on function emerges, and carries with it an undercurrent of an exploitation-exploration dichotomy. Under this interpretation, cells of the ventral stream, which individually have more punctate receptive fields that generally include the fovea or parafovea, provide detailed information about object shapes and features and lead to the systematic exploitation of said information; cells of the dorsal stream, which individually have large receptive fields, contribute to visuospatial perception, provide information about the presence/absence of salient objects and their locations for novel exploration and subsequent exploitation by the ventral stream or, under certain conditions, the dorsal stream. We leverage the dichotomy to unify neuropsychological cases under a common umbrella, account for the increased prevalence of multisensory integration in the dorsal stream under a Bayesian framework, predict conditions under which object recognition utilizes the ventral or dorsal stream, and explain why cells of the dorsal stream drive sensorimotor control and motion processing and have poorer feature selectivity. Finally, the model speculates on a dynamic interaction between the two streams that underscores a unified, seamless perception. Existing theories are subsumed under our proposal.

Biotechnology

NASA Image and Video Library

2003-02-09

Dwarf wheat were photographed aboard the International Space Station in April 2002. Lessons from on-orbit research on plants will have applications to terrestrial agriculture as well as for long-term space missions. Alternative agricultural systems that can efficiently produce greater quantities of high-quality crops in a small area are important for future space expeditions. Also regenerative life-support systems that include plants will be an important component of long-term space missions. Data from the Biomass Production System (BPS) and the Photosynthesis Experiment and System Testing and Operations (PESTO) will advance controlled-environment agricultural systems and will help farmers produce better, healthier crops in a small area. This same knowledge is critical to closed-loop life support systems for spacecraft. The BPS comprises a miniature environmental control system for four plant growth chambers, all in the volume of two space shuttle lockers. The experience with the BPS on orbit is providing valuable design and operational lessons that will be incorporated into the Plant Growth Units. The objective of PESTO was to flight verify the BPS hardware and to determine how the microgravity environment affects the photosynthesis and metabolic function of Super Dwarf wheat and Brassica rapa (a member of the mustard family).

Experimental identification of closely spaced modes using NExT-ERA

NASA Astrophysics Data System (ADS)

Hosseini Kordkheili, S. A.; Momeni Massouleh, S. H.; Hajirezayi, S.; Bahai, H.

2018-01-01

This article presents a study on the capability of the time domain OMA method, NExT-ERA, to identify closely spaced structural dynamic modes. A survey in the literature reveals that few experimental studies have been conducted on the effectiveness of the NExT-ERA methodology in case of closely spaced modes specifically. In this paper we present the formulation for NExT-ERA. This formulation is then implemented in an algorithm and a code, developed in house to identify the modal parameters of different systems using their generated time history data. Some numerical models are firstly investigated to validate the code. Two different case studies involving a plate with closely spaced modes and a pulley ring with greater extent of closeness in repeated modes are presented. Both structures are excited by random impulses under the laboratory condition. The resulting time response acceleration data are then used as input in the developed code to extract modal parameters of the structures. The accuracy of the results is checked against those obtained from experimental tests.

Electrochemical processing of solid waste

NASA Technical Reports Server (NTRS)

Bockris, John OM.

1987-01-01

An investigation of electrochemical waste treatment methods suitable for closed, or partially closed, life support systems for manned space exploration is discussed. The technique being investigated involves the electrolysis of solid waste where the aim is to upgrade waste material (mainly fecal waste) to generate gases that can be recycled in a space station or planetary space environment.

Laser Prevention of Earth Impact Disasters

NASA Technical Reports Server (NTRS)

Campbell, J.; Smalley, L.; Boccio, D.; Howell, Joe T. (Technical Monitor)

2002-01-01

We now believe that while there are about 2000 earth orbit crossing rocks greater than 1 kilometer in diameter, there may be as many as 100,000 or more objects in the 100m size range. Can anything be done about this fundamental existence question facing us? The answer is a resounding yes! We have the technology to prevent collisions. By using an intelligent combination of Earth and space based sensors coupled with an infrastructure of high-energy laser stations and other secondary mitigation options, we can deflect inbound asteroids, meteoroids, and comets and prevent them from striking the Earth. This can be accomplished by irradiating the surface of an inbound rock with sufficiently intense pulses so that ablation occurs. This ablation acts as a small rocket incrementally changing the shape of the rock's orbit around the Sun. One-kilometer size rocks can be moved sufficiently in a month while smaller rocks may be moved in a shorter time span.We recommend that the World's space objectives be immediately reprioritized to start us moving quickly towards a multiple option defense capability. While lasers should be the primary approach, all mitigation options depend on robust early warning, detection, and tracking resources to find objects sufficiently prior to Earth orbit passage in time to allow mitigation. Infrastructure options should include ground, LEO, GEO, Lunar, and libration point laser and sensor stations for providing early warning, tracking, and deflection. Other options should include space interceptors that will carry both laser and nuclear ablators for close range work. Response options must be developed to deal with the consequences of an impact should we move too slowly.

Temporal dynamics of divided spatial attention

PubMed Central

Garcia, Javier O.; Serences, John T.

2013-01-01

In naturalistic settings, observers often have to monitor multiple objects dispersed throughout the visual scene. However, the degree to which spatial attention can be divided across spatially noncontiguous objects has long been debated, particularly when those objects are in close proximity. Moreover, the temporal dynamics of divided attention are unclear: is the process of dividing spatial attention gradual and continuous, or does it onset in a discrete manner? To address these issues, we recorded steady-state visual evoked potentials (SSVEPs) as subjects covertly monitored two flickering targets while ignoring an intervening distractor that flickered at a different frequency. All three stimuli were clustered within either the lower left or the lower right quadrant, and our dependent measure was SSVEP power at the target and distractor frequencies measured over time. In two experiments, we observed a temporally discrete increase in power for target- vs. distractor-evoked SSVEPs extending from ∼350 to 150 ms prior to correct (but not incorrect) responses. The divergence in SSVEP power immediately prior to a correct response suggests that spatial attention can be divided across noncontiguous locations, even when the targets are closely spaced within a single quadrant. In addition, the division of spatial attention appears to be relatively discrete, as opposed to slow and continuous. Finally, the predictive relationship between SSVEP power and behavior demonstrates that these neurophysiological measures of divided attention are meaningfully related to cognitive function. PMID:23390315

Temporal dynamics of divided spatial attention.

PubMed

Itthipuripat, Sirawaj; Garcia, Javier O; Serences, John T

2013-05-01

In naturalistic settings, observers often have to monitor multiple objects dispersed throughout the visual scene. However, the degree to which spatial attention can be divided across spatially noncontiguous objects has long been debated, particularly when those objects are in close proximity. Moreover, the temporal dynamics of divided attention are unclear: is the process of dividing spatial attention gradual and continuous, or does it onset in a discrete manner? To address these issues, we recorded steady-state visual evoked potentials (SSVEPs) as subjects covertly monitored two flickering targets while ignoring an intervening distractor that flickered at a different frequency. All three stimuli were clustered within either the lower left or the lower right quadrant, and our dependent measure was SSVEP power at the target and distractor frequencies measured over time. In two experiments, we observed a temporally discrete increase in power for target- vs. distractor-evoked SSVEPs extending from ∼350 to 150 ms prior to correct (but not incorrect) responses. The divergence in SSVEP power immediately prior to a correct response suggests that spatial attention can be divided across noncontiguous locations, even when the targets are closely spaced within a single quadrant. In addition, the division of spatial attention appears to be relatively discrete, as opposed to slow and continuous. Finally, the predictive relationship between SSVEP power and behavior demonstrates that these neurophysiological measures of divided attention are meaningfully related to cognitive function.

Fly Eye radar: detection through high scattered media

NASA Astrophysics Data System (ADS)

Molchanov, Pavlo; Gorwara, Ashok

2017-05-01

Longer radio frequency waves better penetrating through high scattered media than millimeter waves, but imaging resolution limited by diffraction at longer wavelength. Same time frequency and amplitudes of diffracted waves (frequency domain measurement) provides information of object. Phase shift of diffracted waves (phase front in time domain) consists information about shape of object and can be applied for reconstruction of object shape or even image by recording of multi-frequency digital hologram. Spectrum signature or refracted waves allows identify the object content. Application of monopulse method with overlap closely spaced antenna patterns provides high accuracy measurement of amplitude, phase, and direction to signal source. Digitizing of received signals separately in each antenna relative to processor time provides phase/frequency independence. Fly eye non-scanning multi-frequency radar system provides simultaneous continuous observation of multiple targets and wide possibilities for stepped frequency, simultaneous frequency, chaotic frequency sweeping waveform (CFS), polarization modulation for reliable object detection. Proposed c-band fly eye radar demonstrated human detection through 40 cm concrete brick wall with human and wall material spectrum signatures and can be applied for through wall human detection, landmines, improvised explosive devices detection, underground or camouflaged object imaging.

An energy-saving nonlinear position control strategy for electro-hydraulic servo systems.

PubMed

Baghestan, Keivan; Rezaei, Seyed Mehdi; Talebi, Heidar Ali; Zareinejad, Mohammad

2015-11-01

The electro-hydraulic servo system (EHSS) demonstrates numerous advantages in size and performance compared to other actuation methods. Oftentimes, its utilization in industrial and machinery settings is limited by its inferior efficiency. In this paper, a nonlinear backstepping control algorithm with an energy-saving approach is proposed for position control in the EHSS. To achieve improved efficiency, two control valves including a proportional directional valve (PDV) and a proportional relief valve (PRV) are used to achieve the control objectives. To design the control algorithm, the state space model equations of the system are transformed to their normal form and the control law through the PDV is designed using a backstepping approach for position tracking. Then, another nonlinear set of laws is derived to achieve energy-saving through the PRV input. This control design method, based on the normal form representation, imposes internal dynamics on the closed-loop system. The stability of the internal dynamics is analyzed in special cases of operation. Experimental results verify that both tracking and energy-saving objectives are satisfied for the closed-loop system. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Passive method of eliminating accommodation/convergence disparity in stereoscopic head-mounted displays

NASA Astrophysics Data System (ADS)

Eichenlaub, Jesse B.

2005-03-01

The difference in accommodation and convergence distance experienced when viewing stereoscopic displays has long been recognized as a source of visual discomfort. It is especially problematic in head mounted virtual reality and enhanced reality displays, where images must often be displayed across a large depth range or superimposed on real objects. DTI has demonstrated a novel method of creating stereoscopic images in which the focus and fixation distances are closely matched for all parts of the scene from close distances to infinity. The method is passive in the sense that it does not rely on eye tracking, moving parts, variable focus optics, vibrating optics, or feedback loops. The method uses a rapidly changing illumination pattern in combination with a high speed microdisplay to create cones of light that converge at different distances to form the voxels of a high resolution space filling image. A bench model display was built and a series of visual tests were performed in order to demonstrate the concept and investigate both its capabilities and limitations. Results proved conclusively that real optical images were being formed and that observers had to change their focus to read text or see objects at different distances

Accreting Double White Dwarf Binaries: Implications for LISA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kremer, Kyle; Breivik, Katelyn; Larson, Shane L.

We explore the long-term evolution of mass-transferring white dwarf (WD) binaries undergoing both direct-impact and disk accretion and explore implications of such systems to gravitational-wave (GW) astronomy. We cover a broad range of initial component masses and show that these systems, the majority of which lie within the Laser Interferometer Space Antenna ( LISA ) sensitivity range, exhibit prominent negative orbital frequency evolution (chirp) for a significant fraction of their lifetimes. Using a galactic population synthesis, we predict ∼2700 of these systems will be observable with a negative chirp of 0.1 yr{sup −2} by a space-based GW detector like LISAmore » . We also show that detections of mass-transferring double WD systems by LISA may provide astronomers with unique ways of probing the physics governing close compact object binaries.« less

Spatial and Temporal Distribution of Tuberculosis in the State of Mexico, Mexico

PubMed Central

Zaragoza Bastida, Adrian; Hernández Tellez, Marivel; Bustamante Montes, Lilia P.; Medina Torres, Imelda; Jaramillo Paniagua, Jaime Nicolás; Mendoza Martínez, Germán David; Ramírez Durán, Ninfa

2012-01-01

Tuberculosis (TB) is one of the oldest human diseases that still affects large population groups. According to the World Health Organization (WHO), there were approximately 9.4 million new cases worldwide in the year 2010. In Mexico, there were 18,848 new cases of TB of all clinical variants in 2010. The identification of clusters in space-time is of great interest in epidemiological studies. The objective of this research was to identify the spatial and temporal distribution of TB during the period 2006–2010 in the State of Mexico, using geographic information system (GIS) and SCAN statistics program. Nine significant clusters (P < 0.05) were identified using spatial and space-time analysis. The conclusion is that TB in the State of Mexico is not randomly distributed but is concentrated in areas close to Mexico City. PMID:22919337

Search for light curve modulations among Kepler candidates. Three very low-mass transiting companions

NASA Astrophysics Data System (ADS)

Lillo-Box, J.; Ribas, A.; Barrado, D.; Merín, B.; Bouy, H.

2016-07-01

Context. Light curve modulations in the sample of Kepler planet candidates allows the disentangling of the nature of the transiting object by photometrically measuring its mass. This is possible by detecting the effects of the gravitational pull of the companion (ellipsoidal modulations) and in some cases, the photometric imprints of the Doppler effect when observing in a broad band (Doppler beaming). Aims: We aim to photometrically unveil the nature of some transiting objects showing clear light curve modulations in the phase-folded Kepler light curve. Methods: We selected a subsample among the large crop of Kepler objects of interest (KOIs) based on their chances to show detectable light curve modulations, I.e., close (a< 12 R⋆) and large (in terms of radius, according to their transit signal) candidates. We modeled their phase-folded light curves with consistent equations for the three effects, namely, reflection, ellipsoidal and beaming (known as REB modulations). Results: We provide detailed general equations for the fit of the REB modulations for the case of eccentric orbits. These equations are accurate to the photometric precisions achievable by current and forthcoming instruments and space missions. By using this mathematical apparatus, we find three close-in very low-mass companions (two of them in the brown dwarf mass domain) orbiting main-sequence stars (KOI-554, KOI-1074, and KOI-3728), and reject the planetary nature of the transiting objects (thus classifying them as false positives). In contrast, the detection of the REB modulations and transit/eclipse signal allows the measurement of their mass and radius that can provide important constraints for modeling their interiors since just a few cases of low-mass eclipsing binaries are known. Additionally, these new systems can help to constrain the similarities in the formation process of the more massive and close-in planets (hot Jupiters), brown dwarfs, and very low-mass companions.

Close-up of SSME

NASA Technical Reports Server (NTRS)

1994-01-01

A close-up view of a Space Shuttle Main Engine during a test at the John C. Stennis Space Center shows how the engine is gimballed, or rotated, to evaluate the performance of its components under simulated flight conditions.

Characterization of frictional interference in closely-spaced reinforcements in MSE walls.

DOT National Transportation Integrated Search

2014-09-01

This research addresses one of several knowledge gaps in the understanding of tall MSE wall behavior: prediction of reinforcement loads impacted by frictional interference of closely-spaced reinforcements associated with tall walls.

GNC architecture for autonomous robotic capture of a non-cooperative target: Preliminary concept design

NASA Astrophysics Data System (ADS)

Jankovic, Marko; Paul, Jan; Kirchner, Frank

2016-04-01

Recent studies of the space debris population in low Earth orbit (LEO) have concluded that certain regions have already reached a critical density of objects. This will eventually lead to a cascading process called the Kessler syndrome. The time may have come to seriously consider active debris removal (ADR) missions as the only viable way of preserving the space environment for future generations. Among all objects in the current environment, the SL-8 (Kosmos 3M second stages) rocket bodies (R/Bs) are some of the most suitable targets for future robotic ADR missions. However, to date, an autonomous relative navigation to and capture of an non-cooperative target has never been performed. Therefore, there is a need for more advanced, autonomous and modular systems that can cope with uncontrolled, tumbling objects. The guidance, navigation and control (GNC) system is one of the most critical ones. The main objective of this paper is to present a preliminary concept of a modular GNC architecture that should enable a safe and fuel-efficient capture of a known but uncooperative target, such as Kosmos 3M R/B. In particular, the concept was developed having in mind the most critical part of an ADR mission, i.e. close range proximity operations, and state of the art algorithms in the field of autonomous rendezvous and docking. In the end, a brief description of the hardware in the loop (HIL) testing facility is made, foreseen for the practical evaluation of the developed architecture.

Promoting healthy spacing between pregnancies in India: need for differential education campaigns.

PubMed

Sebastian, Mary Philip; Khan, M E; Roychowdhury, Sohini

2010-12-01

Birth spacing intervals are relatively short in India. Healthy spacing of 3-5 years between births is an effective way to prevent maternal and child mortality and morbidities. Socio-cultural and structural barriers, including limited awareness, socio-cultural norms, and misconceptions need to be addressed for behavior change. Hence the objective was to understand these barriers and accordingly develop separate messages for young women, her husband and her mother-in-law. Data were collected from young women, husbands and mothers-in-law using qualitative methods. Altogether 16 Focus Group Discussions and 30 in-depth interviews were conducted. Beliefs related to need of spacing, disadvantages of closely spaced pregnancies and messages considered suitable for different stakeholders were investigated. Messages were identified for women, husband and mother-in-law; communication aids prepared and community workers trained to appropriately communicate the messages to stakeholders. Quantitative data were collected to measure the effect of the intervention. Educational campaign resulted in higher use of contraceptives for spacing among registered pregnant women from experimental area compared to control area. Differential audience specific educational campaign is feasible and effective. For an effective communication in the community, workers should know how exactly to convey the different health messages to different target population. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

An optical survey for space debris on highly eccentric and inclined MEO orbits

NASA Astrophysics Data System (ADS)

Schildknecht, Thomas; Flohrer, Tim; Hinze, Andreas; Vananti, Alessandro; Silha, Jiri

Optical surveys for space debris in high-altitude orbits have been conducted since more than fifteen years. Originally these efforts concentrated mainly on the geostationary ring (GEO) and its close region. Corresponding observation strategies, processing techniques and cataloguing approaches have been developed and successfully applied. The ESA GEO surveys, e.g., resulted in the detection of a significant population of small-size debris and later in the discovery of high area-to-mass ratio objects in GEO-like orbits. The observation scenarios were successively adapted to survey the geostationary transfer orbit (GTO) region; and surveys to search for debris in the medium Earth orbit (MEO) region of the global navigation satellite constellations were successfully conducted. Comparably less experience (both, in terms of practical observation and strategy definition) is available for eccentric orbits that (at least partly) are in the MEO region, in particular for the Molniya-type orbits. Several breakup events and deliberate fragmentations are known to have taken place in such orbits. Survey and follow-up strategies for searching space debris objects in highly-eccentric MEO orbits, and to acquire orbits which are sufficiently accurate to catalogue such objects and to maintain their orbits over longer time spans were developed and, eventually, optical observations were conducted in the framework of an ESA study using ESA' Space Debris Telescope (ESASDT) the 1-m Zeiss telescope located at the Optical Ground Station (OGS) at the Teide Observatory at Tenerife, Spain. Thirteen nights of surveys of Molniya-type orbits was performed between January and August 2013. A basic survey consisted of observing a single geocentric field for 10 minutes. If a faint object was found, follow-up observations were performed during the same night to ensure a save rediscovery of the object during the next nights. Additional follow-up observations to maintain the orbits of these newly discovered faint objects were also acquired with AIUB's 1 m ZIMLAT telescope in Zimmerwald, Switzerland. Eventually, 255 basic surveys were performed during these thirteen nights corresponding to about 47 hours of observations. In total 30 uncorrelated faint objects were discovered. On average one uncorrelated object was found every 100 minutes. Some of these objects show a considerable brightness variation and have a high area-to-mass ratio as determined in the orbit estimation process. We also investigated the detection efficiency of our surveys by comparing the observation results with the TLE population by means of ESA's PROOF tool. Furthermore a comparison of the real detections with the statistical population of the ESA MASTER-2009 model was performed. The result shows that the fragment population of objects in Molniya-type orbits is underestimated in the MASTER model.

A Comparison of Selective Auditory Attention Abilities in Open-Space Versus Closed Classroom Students.

ERIC Educational Resources Information Center

Reinertsen, Gloria M.

A study compared performances on a test of selective auditory attention between students educated in open-space versus closed classroom environments. An open-space classroom environment was defined as having no walls separating it from hallways or other classrooms. It was hypothesized that the incidence of auditory figure-ground (ability to focus…

Student experiments on Skylab

NASA Technical Reports Server (NTRS)

Floyd, H. B.

1974-01-01

Review of the background and experimental results of the Skylab student project, and assessment of its overall benefits. Virtually all of the objectives of the experiments adopted from student proposals were met. NASA benefited from the program by learning that meaningful experiments could be incorporated into a carry-on or suitcase concept at low cost and within very short time periods. The students benefited greatly from their association with the Skylab program by being afforded a learning opportunity and contact with the real world of research, normally beyond their reach. In addition, hometowns, states, and regions developed a close identification with space exploration.

The Life Cycle Evaluation Model of External Diseconomy of Open-loop Supply Chain

NASA Astrophysics Data System (ADS)

Liu, Qian; Hu, Tianjun

2017-08-01

In recent years, with the continuous deterioration of pollution, resource space is gradually narrowed, the number of waste items increased, people began to use the method of recycling on waste products to ease the pressure on the environment. This paper adopted the external diseconomy of open-loop supply chain as the research object and constructed the model by the life cycle evaluation method, comparative analysis through the case. This paper also concludes that the key to solving the problem is to realize the closed-loop supply chain and building reverse logistics system is of great significance.

Whitson prepares to close PMA2 hatch

NASA Image and Video Library

2007-11-04

S120-E-008857 (4 Nov. 2007) --- Astronaut Peggy Whitson, Expedition 16 commander, prepares to close the hatch in the Pressurized Mating Adapter (PMA-2) of the International Space Station after the STS-120 crewmembers boarded Space Shuttle Discovery for their return trip home. Hatches were closed between the station and the shuttle at 2:03 p.m. (CST) on Nov. 4.

Evolution of double white dwarf binaries undergoing direct-impact accretion: Implications for gravitational wave astronomy

NASA Astrophysics Data System (ADS)

Kremer, Kyle; Breivik, Katelyn; Larson, Shane L.; Kalogera, Vassiliki

2017-01-01

For close double white dwarf binaries, the mass-transfer phenomenon known as direct-impact accretion (when the mass transfer stream impacts the accretor directly rather than forming a disc) may play a pivotal role in the long-term evolution of the systems. In this analysis, we explore the long-term evolution of white dwarf binaries accreting through direct-impact and explore implications of such systems to gravitational wave astronomy. We cover a broad range of parameter space which includes initial component masses and the strength of tidal coupling, and show that these systems, which lie firmly within the LISA frequency range, show strong negative chirps which can last as long as several million years. Detections of double white dwarf systems in the direct-impact phase by detectors such as LISA would provide astronomers with unique ways of probing the physics governing close compact object binaries.

Correlation between microstructure and thermionic electron emission from Os-Ru thin films on dispenser cathodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swartzentruber, Phillip D.; John Balk, Thomas, E-mail: john.balk@uky.edu; Effgen, Michael P.

2014-07-01

Osmium-ruthenium films with different microstructures were deposited onto dispenser cathodes and subjected to 1000 h of close-spaced diode testing. Tailored microstructures were achieved by applying substrate biasing during deposition, and these were evaluated with scanning electron microscopy, x-ray diffraction, and energy dispersive x-ray spectroscopy before and after close-spaced diode testing. Knee temperatures determined from the close-spaced diode test data were used to evaluate cathode performance. Cathodes with a large (10-11) Os-Ru film texture possessed comparatively low knee temperatures. Furthermore, a low knee temperature correlated with a low effective work function as calculated from the close-spaced diode data. It is proposedmore » that the formation of strong (10-11) texture is responsible for the superior performance of the cathode with a multilayered Os-Ru coating.« less

Scout: orbit analysis and hazard assessment for NEOCP objects

NASA Astrophysics Data System (ADS)

Farnocchia, Davide; Chesley, Steven R.; Chamberlin, Alan B.

2016-10-01

It typically takes a few days for a newly discovered asteroid to be officially recognized as a real object. During this time, the tentative discovery is published on the Minor Planet Center's Near-Earth Object Confirmation Page (NEOCP) until additional observations confirm that the object is a real asteroid rather than an observational artifact or an artificial object. Also, NEOCP objects could have a limited observability window and yet be scientifically interesting, e.g., radar and lightcurve targets, mini-moons (temporary Earth captures), mission accessible targets, close approachers or even impactors. For instance, the only two asteroids discovered before an impact, 2008 TC3 and 2014 AA, both reached the Earth less than a day after discovery. For these reasons we developed Scout, an automated system that provides an orbital and hazard assessment for NEOCP objects within minutes after the observations are available. Scout's rapid analysis increases the chances of securing the trajectory of interesting NEOCP objects before the ephemeris uncertainty grows too large or the observing geometry becomes unfavorable. The generally short observation arcs, perhaps only a few hours or even less, lead severe degeneracies in the orbit estimation process. To overcome these degeneracies Scout relies on systematic ranging, a technique that derives possible orbits by scanning a grid in the poorly constrained space of topocentric range and range rate, while the plane-of-sky position and motion are directly tied to the recorded observations. This scan allows us to derive a distribution of the possible orbits and in turn identify the NEOCP objects of most interest to prioritize followup efforts. In particular, Scout ranks objects according to the likelihood of an impact, estimates the close approach distance, the Earth-relative minimum orbit intersection distance and v-infinity, and computes scores to identify objects more likely to be an NEO, a km-sized NEO, a Potentially Hazardous Asteroid, and those on a geocentric orbit. Moreover, Scout provides an ephemeris service that makes use of the statistical information to support observers in their followup efforts.

Apparatus for retaining and releasing a payload

NASA Technical Reports Server (NTRS)

Carrier, Alain (Inventor); Cobb, Bruce (Inventor)

2000-01-01

An apparatus for latching an object, such as a payload for a space vehicle, includes an expandible latch which is shifted between a relaxed open condition and a flexed closed condition by actuation of a pair of temperature-responsive members, such as shaped memory alloy (SMA) coil springs. One of the two temperature-responsive members biases an actuator into a first position that allows the expandible latch to open. The other SMA member biases the actuator in the opposite position to close the expandible latch. Heating the appropriate SMA member causes the actuator to move from one position to the other position. In the preferred embodiment, no power is required to maintain the actuator in either position once the position has been established. For example, the actuator may have a rest position that allows the expandible latch to remain open when the two SMA members are cooled and allowed to reach an equilibrium condition with respect to applied force to the actuator. A detent-and-ball arrangement may be used to maintain the position of the actuator after the expandible latch has been closed.

English/Russian terminology on radiometric calibration of space-borne optoelectronic sensors

NASA Astrophysics Data System (ADS)

Privalsky, V.; Zakharenkov, V.; Humpherys, T.; Sapritsky, V.; Datla, R.

The efficient use of data acquired through exo-atmospheric observations of the Earth within the framework of existing and newly planned programs requires a unique understanding of respective terms and definitions. Yet, the last large-scale document on the subject - The International Electrotechnical Vocabulary - had been published 18 years ago. This lack of a proper document, which would reflect the changes that had occurred in the area since that time, is especially detrimental to the developing international efforts aimed at global observations of the Earth from space such as the Global Earth Observations Program proposed by the U.S.A. at the 2003 WMO Congress. To cover this gap at least partially, a bi-lingual explanatory dictionary of terms and definitions in the area of radiometric calibration of space-borne IR sensors is developed. The objectives are to produce a uniform terminology for the global space-borne observations of the Earth, establish a unique understanding of terms and definitions by the radiometric communities, including a correspondence between the Russian and American terms and definitions, and to develop a formal English/Russian reference dictionary for use by scientists and engineers involved in radiometric observations of the Earth from space. The dictionary includes close to 400 items covering basic concepts of geometric, wave and corpuscular optics, remote sensing technologies, and ground-based calibration as well as more detailed treatment of terms and definitions in the areas of radiometric quantities, symbols and units, optical phenomena and optical properties of objects and media, and radiometric systems and their properties. The dictionary contains six chapters: Basic Concepts, Quantities, Symbols, and Units, Optical phenomena, Optical characteristics of surfaces and media, Components of Radiometric Systems, Characteristics of radiometric system components, plus English/Russian and Russian/Inglish indices.

Kuiper Belt Objects Along the Pluto Express Path

NASA Technical Reports Server (NTRS)

Jewitt, David C.

1998-01-01

The science objective of this work was to identify objects in the Kuiper Belt which will, in the 5 years following Pluto encounter, be close to the flight path of NASA's Pluto-Kuiper Express. Currently, launch is scheduled for 2004 with a flight time of about 1 decade. Early identification of post-Pluto targets is important for mission design and orbit refinement. An object or objects close enough to the flight path can be visited and studied at high resolution, using only residual gas in the thrusters to affect a close encounter.

Microbial Existence in Controlled Habitats and Their Resistance to Space Conditions

PubMed Central

Venkateswaran, Kasthuri; La Duc, Myron T.; Horneck, Gerda

2014-01-01

The National Research Council (NRC) has recently recognized the International Space Station (ISS) as uniquely suitable for furthering the study of microbial species in closed habitats. Answering the NRC’s call for the study, in particular, of uncommon microbial species in the ISS, and/or of those that have significantly increased or decreased in number, space microbiologists have begun capitalizing on the maturity, speed, and cost-effectiveness of molecular/genomic microbiological technologies to elucidate changes in microbial populations in the ISS and other closed habitats. Since investigators can only collect samples infrequently from the ISS itself due to logistical reasons, Earth analogs, such as spacecraft-assembly clean rooms, are used and extensively characterized for the presence of microbes. Microbiologists identify the predominant, problematic, and extremophilic microbial species in these closed habitats and use the ISS as a testbed to study their resistance to extreme extraterrestrial environmental conditions. Investigators monitor the microbes exposed to the real space conditions in order to track their genomic changes in response to the selective pressures present in outer space (external to the ISS) and the spaceflight (in the interior of the ISS). In this review, we discussed the presence of microbes in space research-related closed habitats and the resistance of some microbial species to the extreme environmental conditions of space. PMID:25130881

Microbial existence in controlled habitats and their resistance to space conditions.

PubMed

Venkateswaran, Kasthuri; La Duc, Myron T; Horneck, Gerda

2014-09-17

The National Research Council (NRC) has recently recognized the International Space Station (ISS) as uniquely suitable for furthering the study of microbial species in closed habitats. Answering the NRC's call for the study, in particular, of uncommon microbial species in the ISS, and/or of those that have significantly increased or decreased in number, space microbiologists have begun capitalizing on the maturity, speed, and cost-effectiveness of molecular/genomic microbiological technologies to elucidate changes in microbial populations in the ISS and other closed habitats. Since investigators can only collect samples infrequently from the ISS itself due to logistical reasons, Earth analogs, such as spacecraft-assembly clean rooms, are used and extensively characterized for the presence of microbes. Microbiologists identify the predominant, problematic, and extremophilic microbial species in these closed habitats and use the ISS as a testbed to study their resistance to extreme extraterrestrial environmental conditions. Investigators monitor the microbes exposed to the real space conditions in order to track their genomic changes in response to the selective pressures present in outer space (external to the ISS) and the spaceflight (in the interior of the ISS). In this review, we discussed the presence of microbes in space research-related closed habitats and the resistance of some microbial species to the extreme environmental conditions of space.

Close up view of the Orbiter Discovery in the Orbiter ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Close up view of the Orbiter Discovery in the Orbiter Processing Facility at Kennedy Space Center. The view is a detail of the aft, starboard landing gear and a general view of the Thermal Protection System tiles around the landing-gear housing. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

Entanglement branes in a two-dimensional string theory

DOE PAGES

Donnelly, William; Wong, Gabriel

2017-09-20

What is the meaning of entanglement in a theory of extended objects such as strings? To address this question we consider the spatial entanglement between two intervals in the Gross-Taylor model, the string theory dual to two-dimensional Yang-Mills theory at large N. The string diagrams that contribute to the entanglement entropy describe open strings with endpoints anchored to the entangling surface, as first argued by Susskind. We develop a canonical theory of these open strings, and describe how closed strings are divided into open strings at the level of the Hilbert space. Here, we derive the modular Hamiltonian for themore » Hartle-Hawking state and show that the corresponding reduced density matrix describes a thermal ensemble of open strings ending on an object at the entangling surface that we call an entanglement brane, or E-brane.« less

Approximations and Solution Estimates in Optimization

DTIC Science & Technology

2016-04-06

comprehensive descriptions of epi-convergence and its connections to variational analysis broadly. Our motivation for going beyond normed linear spaces , which...proper, every closed ball in this metric space is compact and the existence of solutions of such optimal fitting problems is more easily established...lsc-fcns(X), dl(fν , f) → 0 implies that fν epi-converges to f. We recall that a metric space is proper if every closed ball in that space is compact

Nonlinear features for classification and pose estimation of machined parts from single views

NASA Astrophysics Data System (ADS)

Talukder, Ashit; Casasent, David P.

1998-10-01

A new nonlinear feature extraction method is presented for classification and pose estimation of objects from single views. The feature extraction method is called the maximum representation and discrimination feature (MRDF) method. The nonlinear MRDF transformations to use are obtained in closed form, and offer significant advantages compared to nonlinear neural network implementations. The features extracted are useful for both object discrimination (classification) and object representation (pose estimation). We consider MRDFs on image data, provide a new 2-stage nonlinear MRDF solution, and show it specializes to well-known linear and nonlinear image processing transforms under certain conditions. We show the use of MRDF in estimating the class and pose of images of rendered solid CAD models of machine parts from single views using a feature-space trajectory neural network classifier. We show new results with better classification and pose estimation accuracy than are achieved by standard principal component analysis and Fukunaga-Koontz feature extraction methods.

Spatial Factors in the Integration of Speed Information

NASA Technical Reports Server (NTRS)

Verghese, P.; Stone, L. S.; Hargens, Alan R. (Technical Monitor)

1995-01-01

We reported that, for a 21FC task with multiple Gabor patches in each interval, thresholds for speed discrimination decreased with the number of patches, while simply increasing the area of a single patch produced no such effect. This result could be explained by multiple patches reducing spatial uncertainty. However, the fact that thresholds decrease with number even when the patches are in fixed positions argues against this explanation. We therefore performed additional experiments to explore the lack of an area effect. Three observers did a 21FC speed discrimination task with 6 Gabor patches in each interval, and were asked to pick the interval in which the gratings moved faster. The 50% contrast patches were placed on a circle at 4 deg. eccentricity, either equally spaced and maximally separated (hexagonal array), or closely-spaced, in consecutive positions (string of pearls). For the string-of-pearls condition, the grating phases were either random, or consistent with a full-field grating viewed through multiple Gaussian windows. When grating phases were random, the thresholds for the hexagonal and string-of-pearls layouts were indistinguishable. For the string-of-pearls layout, thresholds in the consistent-phase condition were higher by 15 +/- 6% than in the random-phase condition. (Thresholds increased by 57 +/- 7% in going from 6 patches to a single patch of equivalent area.). For random-phase patches, the lower thresholds for 6 patches does not depend on a specific spacing or spatial layout. Multiple, closely-spaced, consistent-phase patches that can be interpreted as a single grating, result in thresholds closer to that produced by a single patch. Together, our results suggest that object segmentation may play a role in the integration of speed information.

14 CFR 417.19 - Registration of space objects.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Registration of space objects. 417.19 Section 417.19 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... Registration of space objects. (a) To assist the U.S. Government in implementing Article IV of the 1975...

14 CFR 417.19 - Registration of space objects.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Registration of space objects. 417.19 Section 417.19 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... Registration of space objects. (a) To assist the U.S. Government in implementing Article IV of the 1975...

14 CFR 417.19 - Registration of space objects.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Registration of space objects. 417.19 Section 417.19 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... Registration of space objects. (a) To assist the U.S. Government in implementing Article IV of the 1975...

14 CFR 417.19 - Registration of space objects.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Registration of space objects. 417.19 Section 417.19 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... Registration of space objects. (a) To assist the U.S. Government in implementing Article IV of the 1975...

14 CFR 417.19 - Registration of space objects.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Registration of space objects. 417.19 Section 417.19 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... Registration of space objects. (a) To assist the U.S. Government in implementing Article IV of the 1975...

Burbank and Kuipers close hatch

NASA Image and Video Library

2012-03-24

ISS030-E-173924 (24 March 2012) --- NASA astronaut Dan Burbank (left), Expedition 30 commander; and European Space Agency astronaut Andre Kuipers, flight engineer, close a hatch in the International Space Station as crew members prepare to move to the appropriate Soyuz vehicles, due to the possibility that space debris could pass close to the station. Burbank, Shkaplerov and Ivanishin sheltered in the Soyuz TMA-22 spacecraft attached to the Poisk Mini-Research Module 2 (MRM2) while Kononenko, Kuipers and Pettit took to the Soyuz TMA-03M docked to the Rassvet Mini-Research Module 1 (MRM-1).

Close up detail of the underside of the Orbiter Discovery ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Close up detail of the underside of the Orbiter Discovery in the Vehicle Assembly Building at NASA's Kennedy Space Center. This view is from underneath the aft section looking forward. It is a close-up view of the High-temperature Reusable Surface Insulation tiles showing the wear patterns from the heat of reentry, consequential replacement of worn and damaged tiles. The wear and replacement patters are unique to each Orbiter which can serve as their particular "fingerprint". - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

Flat connections in open string mirror symmetry

NASA Astrophysics Data System (ADS)

Alim, Murad; Hecht, Michael; Jockers, Hans; Mayr, Peter; Mertens, Adrian; Soroush, Masoud

2012-06-01

We study a flat connection defined on the open-closed deformation space of open string mirror symmetry for type II compactifications on Calabi-Yau threefolds with D-branes. We use flatness and integrability conditions to define distinguished flat coordinates and the superpotential function at an arbitrary point in the open-closed deformation space. Integrability conditions are given for concrete deformation spaces with several closed and open string deformations. We study explicit examples for expansions around different limit points, including orbifold Gromov-Witten invariants, and brane configurations with several brane moduli. In particular, the latter case covers stacks of parallel branes with non-Abelian symmetry.

Presence of closely spaced protein thiols on the surface of mammalian cells.

PubMed Central

Donoghue, N.; Yam, P. T.; Jiang, X. M.; Hogg, P. J.

2000-01-01

It has been proposed that certain cell-surface proteins undergo redox reactions, that is, transfer of hydrogens and electrons between closely spaced cysteine thiols that can lead to reduction, formation, or interchange of disulfide bonds. This concept was tested using a membrane-impermeable trivalent arsenical to identify closely spaced thiols in cell-surface proteins. We attached the trivalent arsenical, phenylarsenoxide, to the thiol of reduced glutathione to produce 4-(N-(S-glutathionylacetyl)amino)phenylarsenoxide (GSAO). GSAO bound tightly to synthetic, peptide, and protein dithiols like thioredoxin, but not to monothiols. To identify cell-surface proteins that contain closely spaced thiols, we attached a biotin moiety through a spacer arm to the primary amino group of the gamma-glutamyl residue of GSAO (GSAO-B). Incorporation of GSAO-B into proteins was assessed by measuring the biotin using streptavidin-peroxidase. Up to 12 distinct proteins were labeled with GSAO-B on the surface of endothelial and fibrosarcoma cells. The pattern of labeled proteins differed between the different cell types. Protein disulfide isomerase was one of the proteins on the endothelial and fibrosarcoma cell surface that incorporated GSAO-B. These findings demonstrate that the cell-surface environment can support the existence of closely spaced protein thiols and suggest that at least some of these thiols are redox active. PMID:11206065

Cortical neurons of bats respond best to echoes from nearest targets when listening to natural biosonar multi-echo streams.

PubMed

Beetz, M Jerome; Hechavarría, Julio C; Kössl, Manfred

2016-10-27

Bats orientate in darkness by listening to echoes from their biosonar calls, a behaviour known as echolocation. Recent studies showed that cortical neurons respond in a highly selective manner when stimulated with natural echolocation sequences that contain echoes from single targets. However, it remains unknown how cortical neurons process echolocation sequences containing echo information from multiple objects. In the present study, we used echolocation sequences containing echoes from three, two or one object separated in the space depth as stimuli to study neuronal activity in the bat auditory cortex. Neuronal activity was recorded with multi-electrode arrays placed in the dorsal auditory cortex, where neurons tuned to target-distance are found. Our results show that target-distance encoding neurons are mostly selective to echoes coming from the closest object, and that the representation of echo information from distant objects is selectively suppressed. This suppression extends over a large part of the dorsal auditory cortex and may override possible parallel processing of multiple objects. The presented data suggest that global cortical suppression might establish a cortical "default mode" that allows selectively focusing on close obstacle even without active attention from the animals.

Cortical neurons of bats respond best to echoes from nearest targets when listening to natural biosonar multi-echo streams

PubMed Central

Beetz, M. Jerome; Hechavarría, Julio C.; Kössl, Manfred

2016-01-01

Bats orientate in darkness by listening to echoes from their biosonar calls, a behaviour known as echolocation. Recent studies showed that cortical neurons respond in a highly selective manner when stimulated with natural echolocation sequences that contain echoes from single targets. However, it remains unknown how cortical neurons process echolocation sequences containing echo information from multiple objects. In the present study, we used echolocation sequences containing echoes from three, two or one object separated in the space depth as stimuli to study neuronal activity in the bat auditory cortex. Neuronal activity was recorded with multi-electrode arrays placed in the dorsal auditory cortex, where neurons tuned to target-distance are found. Our results show that target-distance encoding neurons are mostly selective to echoes coming from the closest object, and that the representation of echo information from distant objects is selectively suppressed. This suppression extends over a large part of the dorsal auditory cortex and may override possible parallel processing of multiple objects. The presented data suggest that global cortical suppression might establish a cortical “default mode” that allows selectively focusing on close obstacle even without active attention from the animals. PMID:27786252

Expanding Coherent Array Processing to Larger Apertures Using Empirical Matched Field Processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ringdal, F; Harris, D B; Kvaerna, T

2009-07-23

We have adapted matched field processing, a method developed in underwater acoustics to detect and locate targets, to classify transient seismic signals arising from mining explosions. Matched field processing, as we apply it, is an empirical technique, using observations of historic events to calibrate the amplitude and phase structure of wavefields incident upon an array aperture for particular repeating sources. The objective of this project is to determine how broadly applicable the method is and to understand the phenomena that control its performance. We obtained our original results in distinguishing events from ten mines in the Khibiny and Olenegorsk miningmore » districts of the Kola Peninsula, for which we had exceptional ground truth information. In a cross-validation test, some 98.2% of 549 explosions were correctly classified by originating mine using just the Pn observations (2.5-12.5 Hz) on the ARCES array at ranges from 350-410 kilometers. These results were achieved despite the fact that the mines are as closely spaced as 3 kilometers. Such classification performance is significantly better than predicted by the Rayleigh limit. Scattering phenomena account for the increased resolution, as we make clear in an analysis of the information carrying capacity of Pn under two alternative propagation scenarios: free-space propagation and propagation with realistic (actually measured) spatial covariance structure. The increase in information capacity over a wide band is captured by the matched field calibrations and used to separate explosions from very closely-spaced sources. In part, the improvement occurs because the calibrations enable coherent processing at frequencies above those normally considered coherent. We are investigating whether similar results can be expected in different regions, with apertures of increasing scale and for diffuse seismicity. We verified similar performance with the closely-spaced Zapolyarni mines, though discovered that it may be necessary to divide event populations from a single mine into identifiable subpopulations. For this purpose, we perform cluster analysis using matched field statistics calculated on pairs of individual events as a distance metric. In our initial work, calibrations were derived from ensembles of events ranging in number to more than 100. We are considering the performance now of matched field calibrations derived with many fewer events (even, as mentioned, individual events). Since these are high-variance estimates, we are testing the use of cross-channel, multitaper, spectral estimation methods to reduce the variance of calibrations and detection statistics derived from single-event observations. To test the applicability of the technique in a different tectonic region, we have obtained four years of continuous data from 4 Kazakh arrays and are extracting large numbers of event segments. Our initial results using 132 mining explosions recorded by the Makanchi array are similar to those obtained in the European Arctic. Matched field processing clearly separates the explosions from three closely-spaced mines located approximately 400 kilometers from the array, again using waveforms in a band (6-10 Hz) normally considered incoherent for this array. Having reproduced ARCES-type performance with another small aperture array, we have two additional objectives for matched field processing. We will attempt to extend matched field processing to larger apertures: a 200 km aperture (the KNET) and, if data permit, to an aperture comprised of several Kazakh arrays. We also will investigate the potential of developing matched field processing to roughly locate and classify natural seismicity, which is more diffuse than the concentrated sources of mining explosions that we have investigated to date.« less

Hubble’s cross-section of the cosmos

NASA Image and Video Library

2014-04-17

This new Hubble image showcases a remarkable variety of objects at different distances from us, extending back over halfway to the edge of the observable Universe. The galaxies in this image mostly lie about five billion light-years from Earth but the field also contains other objects, both significantly closer and far more distant. Studies of this region of the sky have shown that many of the objects that appear to lie close together may actually be billions of light-years apart. This is because several groups of galaxies lie along our line of sight, creating something of an optical illusion. Hubble’s cross-section of the Universe is completed by distorted images of galaxies in the very distant background. These objects are sometimes distorted due to a process called gravitational lensing, an extremely valuable technique in astronomy for studying very distant objects [1]. This lensing is caused by the bending of the space-time continuum by massive galaxies lying close to our line of sight to distant objects. One of the lens systems visible here is called CLASS B1608+656, which appears as a small loop in the centre of the image. It features two foreground galaxies distorting and amplifying the light of a distant quasar the known as QSO-160913+653228. The light from this bright disc of matter, which is currently falling into a black hole, has taken nine billion years to reach us — two thirds of the age of the Universe. As well as CLASS B1608+656, astronomers have identified two other gravitational lenses within this image. Two galaxies, dubbed Fred and Ginger by the researchers who studied them, contain enough mass to visibly distort the light from objects behind them. Fred, also known more prosaically as [FMK2006] ACS J160919+6532, lies near the lens galaxies in CLASS B1608+656, while Ginger ([FMK2006] ACS J160910+6532) is markedly closer to us. Despite their different distances from us, both can be seen near to CLASS B1608+656 in the central region of this Hubble image. To capture distant and dim objects like these, Hubble required a long exposure. The image is made up of visible and infrared observations with a total exposure time of 14 hours. More info: www.spacetelescope.org/news/heic1408/ Credit: NASA/ESA/Hubble NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Architecture Design for the Space Situational Awareness System in the Preparedness Plan for Space Hazards of Republic of Korea

NASA Astrophysics Data System (ADS)

Choi, E.; Cho, S.; Shin, S.; Park, J.; Kim, J.; Kim, D.

The threat posed by asteroids and comets has become one of the important issues. Jinju meteorite discovered in March 2014 has expanded the interest of the people of the fall of the natural space objects. Furthermore, the growing quantity of space debris is a serious threat to satellites and other spacecraft, which risk being damaged or even destroyed. In May of 2014, Korea established the preparedness plan for space hazards according to the space development promotion act which is amended to take action with respect to hazards from space. This plan is largely composed of 3 items such as system, technology and infrastructure. System is included the establishment and management of national space hazards headquarters at risk situation. Korea Astronomy and Space Science Institute (KASI) was designated as a space environment monitoring agency under the ministry of science, ICT and future planning (MSIP). Technology is supposed to develop the space situational awareness system that can monitor and detect space objects. For infrastructure, research and development of core technology will be promoted for capabilities improvement of space hazards preparedness such as software tools, application and data systems. This paper presents the architectural design for building space situational awareness system. The trade-off study of space situational awareness system for the Korea situation was performed. The results have shown the proposed architectural design. The baseline architecture is composed of Integrated Analysis System and Space Objects Monitoring System. Integrated Analysis System collects the status data from Space Objects Monitoring System and analyzes the space risk information through a data processing. For Space Objects Monitoring System, the all-sky surveillance camera, array radar and meteoroid surveillance sensor networks were considered. This system focuses on not only the threat of a large artificial satellite and natural space objects such as asteroids that crashed to Earth but also the prediction of potential collisions between space objects. Especially, array radar aims to accurately track space objects. By analyzing performance for radar system and sensor networks, several feasible approaches for such a space objects monitoring system will be presented in this paper.

Assessment of Technologies for the Space Shuttle External Tank Thermal Protection System and Recommendations for Technology Improvement - Part III: Material Property Characterization, Analysis, and Test Methods

NASA Technical Reports Server (NTRS)

Gates, Thomas S.; Johnson, Theodore F.; Whitley, Karen S.

2005-01-01

The objective of this report is to contribute to the independent assessment of the Space Shuttle External Tank Foam Material. This report specifically addresses material modeling, characterization testing, data reduction methods, and data pedigree. A brief description of the External Tank foam materials, locations, and standard failure modes is provided to develop suitable background information. A review of mechanics based analysis methods from the open literature is used to provide an assessment of the state-of-the-art in material modeling of closed cell foams. Further, this report assesses the existing material property database and investigates sources of material property variability. The report presents identified deficiencies in testing methods and procedures, recommendations for additional testing as required, identification of near-term improvements that should be pursued, and long-term capabilities or enhancements that should be developed.

Requirements for significant problem reporting and trend analysis

NASA Technical Reports Server (NTRS)

1988-01-01

This handbook supplements policies, requirements, and procedures of NMI 8070.3 to ensure that NASA management at each organizational level is: fully aware of trends affecting both the level of safety and the potential for mission success established for both NASA manned space programs and its supporting institutions; fully and independently informed of problems that represent significant risk to the safety of all personnel (including the general populace) and to the success of a mission or operation through a program mechanism herein defined as Significant Problem Reporting; and in full agreement with the level of elimination of these problems through the closed-loop accounting of corrective actions. The requirements of this handbook are supportive of the agency's safety, reliability, maintainability, and quality assurance (SRM&QA) program objectives and are applicable to all organizational elements of NASA connected with or supporting developmental or operational manned space program/projects (including associated payloads) and the related institutional facilities.

A vehicle health monitoring system for the Space Shuttle Reaction Control System during reentry. M.S. Thesis - Massachusetts Inst. of Technology

NASA Technical Reports Server (NTRS)

Rosello, Anthony David

1995-01-01

A general two tier framework for vehicle health monitoring of Guidance Navigation and Control (GN&C) system actuators, effectors, and propulsion devices is presented. In this context, a top level monitor that estimates jet thrust is designed for the Space Shuttle Reaction Control System (RCS) during the reentry phase of flight. Issues of importance for the use of estimation technologies in vehicle health monitoring are investigated and quantified for the Shuttle RCS demonstration application. These issues include rate of convergence, robustness to unmodeled dynamics, sensor quality, sensor data rates, and information recording objectives. Closed loop simulations indicate that a Kalman filter design is sensitive to modeling error and robust estimators may reduce this sensitivity. Jet plume interaction with the aerodynamic flowfield is shown to be a significant effect adversely impacting the ability to accurately estimate thrust.

Evaluation of engineered foods for Closed Ecological Life Support System (CELSS)

NASA Technical Reports Server (NTRS)

Karel, M.

1981-01-01

A system of conversion of locally regenerated raw materials and of resupplied freeze-dried foods and ingredients into acceptable, safe and nutritious engineered foods is proposed. The first phase of the proposed research has the following objectives: (1) evaluation of feasibility of developing acceptable and reliable engineered foods from a limited selection of plants, supplemented by microbially produced nutrients and a minimum of dehydrated nutrient sources (especially those of animal origin); (2) evaluation of research tasks and specifications of research projects to adapt present technology and food science to expected space conditions (in particular, problems arising from unusual gravity conditions, problems of limited size and the isolation of the food production system, and the opportunities of space conditions are considered); (3) development of scenarios of agricultural production of plant and microbial systems, including the specifications of processing wastes to be recycled.

The Observing Modes of JWST/NIRISS

NASA Astrophysics Data System (ADS)

Taylor, Joanna M.; NIRISS Team

2018-06-01

The Near Infrared Imager and Slitless Spectrograph (NIRISS) is a contribution of the Canadian Space Agency to the James Webb Space Telescope (JWST). NIRISS complements the other near-infrared science instruments onboard JWST by providing capabilities for (a) low resolution grism spectroscopy between 0.8 and 2.2 µm over the entire field of view, with the possibility of observing the same scene with orthogonal dispersion directions to disentangle blended objects; (b) medium-resolution grism spectroscopy between 0.6 and 2.8 µm that has been optimized to provide high spectrophotometric stability for time-series observations of transiting exoplanets; (c) aperture masking interferometry that provides high angular resolution of 70 - 400 mas at wavelengths between 2.8 and 4.8 µm and (d) parallel imaging through a set of filters that are closely matched to NIRCam's.In this poster, we discuss each of these modes and present simulations of how they might typically be used to address specific scientific questions.

Space Station CMIF extended duration metabolic control test

NASA Technical Reports Server (NTRS)

Schunk, Richard G.; Bagdigian, Robert M.; Carrasquillo, Robyn L.; Ogle, Kathryn Y.; Wieland, Paul O.

1989-01-01

The Space Station Extended Duration Metabolic Control Test (EMCT) was conducted at the MSFC Core Module Integration Facility. The primary objective of the EMCT was to gather performance data from a partially-closed regenerative Environmental Control and Life Support (ECLS) system functioning under steady-state conditions. Included is a description of the EMCT configuration, a summary of events, a discussion of anomalies that occurred during the test, and detailed results and analysis from individual measurements of water and gas samples taken during the test. A comparison of the physical, chemical, and microbiological methods used in the post test laboratory analyses of the water samples is included. The preprototype ECLS hardware used in the test, providing an overall process description and theory of operation for each hardware item. Analytical results pertaining to a system level mass balance and selected system power estimates are also included.

The materials processing research base of the Materials Processing Center. Report for FY 1982

NASA Technical Reports Server (NTRS)

Flemings, M. C.

1983-01-01

The work described, while involving research in the broad field of materials processing, has two common features: the problems are closed related to space precessing of materials and have both practical and fundamental significance. An interesting and important feature of many of the projects is that the interdisciplinary nature of the problem mandates complementary analytical modeling/experimental approaches. An other important aspect of many of the projects is the increasing use of mathematical modeling techniques as one of the research tools. The predictive capability of these models, when tested against measurements, plays a very important role in both the planning of experimental programs and in the rational interpretation of the results. Many of the projects described have a space experiment as their ultimate objective. Mathematical models are proving to be extremely valuable in projecting the findings of ground - based experiments to microgravity conditions.

Constrained space camera assembly

DOEpatents

Heckendorn, Frank M.; Anderson, Erin K.; Robinson, Casandra W.; Haynes, Harriet B.

1999-01-01

A constrained space camera assembly which is intended to be lowered through a hole into a tank, a borehole or another cavity. The assembly includes a generally cylindrical chamber comprising a head and a body and a wiring-carrying conduit extending from the chamber. Means are included in the chamber for rotating the body about the head without breaking an airtight seal formed therebetween. The assembly may be pressurized and accompanied with a pressure sensing means for sensing if a breach has occurred in the assembly. In one embodiment, two cameras, separated from their respective lenses, are installed on a mounting apparatus disposed in the chamber. The mounting apparatus includes means allowing both longitudinal and lateral movement of the cameras. Moving the cameras longitudinally focuses the cameras, and moving the cameras laterally away from one another effectively converges the cameras so that close objects can be viewed. The assembly further includes means for moving lenses of different magnification forward of the cameras.

New nonlinear control algorithms for multiple robot arms

NASA Technical Reports Server (NTRS)

Tarn, T. J.; Bejczy, A. K.; Yun, X.

1988-01-01

Multiple coordinated robot arms are modeled by considering the arms as closed kinematic chains and as a force-constrained mechanical system working on the same object simultaneously. In both formulations, a novel dynamic control method is discussed. It is based on feedback linearization and simultaneous output decoupling technique. By applying a nonlinear feedback and a nonlinear coordinate transformation, the complicated model of the multiple robot arms in either formulation is converted into a linear and output decoupled system. The linear system control theory and optimal control theory are used to design robust controllers in the task space. The first formulation has the advantage of automatically handling the coordination and load distribution among the robot arms. In the second formulation, it was found that by choosing a general output equation it became possible simultaneously to superimpose the position and velocity error feedback with the force-torque error feedback in the task space.

Improving Fermi Orbit Determination and Prediction in an Uncertain Atmospheric Drag Environment

NASA Technical Reports Server (NTRS)

Vavrina, Matthew A.; Newman, Clark P.; Slojkowski, Steven E.; Carpenter, J. Russell

2014-01-01

Orbit determination and prediction of the Fermi Gamma-ray Space Telescope trajectory is strongly impacted by the unpredictability and variability of atmospheric density and the spacecraft's ballistic coefficient. Operationally, Global Positioning System point solutions are processed with an extended Kalman filter for orbit determination, and predictions are generated for conjunction assessment with secondary objects. When these predictions are compared to Joint Space Operations Center radar-based solutions, the close approach distance between the two predictions can greatly differ ahead of the conjunction. This work explores strategies for improving prediction accuracy and helps to explain the prediction disparities. Namely, a tuning analysis is performed to determine atmospheric drag modeling and filter parameters that can improve orbit determination as well as prediction accuracy. A 45% improvement in three-day prediction accuracy is realized by tuning the ballistic coefficient and atmospheric density stochastic models, measurement frequency, and other modeling and filter parameters.

Scientific support for an orbiter middeck experiment on solid surface combustion

NASA Technical Reports Server (NTRS)

Altenkirch, Robert A.; Vedha-Nayagam, M.; Srikantaiah, Nataraj

1988-01-01

The objective is to determine the mechanism of gas-phase flame spread over solid fuel surfaces in the absence of any buoyancy or externally imposed gas-phase flow. Such understanding can be used to improve the fire safety aspects of space travel by providing information that will allow judicious selections of spacecraft materials and environments to be made. The planned experiment consists of measuring the flame spread rate over thermally thin and thermally thick fuels in a closed container in the low-gravity environment of the Space Shuttle. Measurements consist of flame spread rate and shape obtained from two views of the process as recorded on movie film and surface and gas-phase temperatures obtained from fine-wire thermocouples. The temperature measurements along with appropriate modeling provide information about the gas-to-solid heat flux. Environmental parameters to be varied are the oxygen concentration and pressure.

Close-Range Photogrammetry & Next Generation Spacecraft

NASA Technical Reports Server (NTRS)

Pappa, Richard S.

2002-01-01

NASA is focusing renewed attention on the topic of large, ultra-lightweight space structures, also known as 'gossamer' spacecraft. Nearly all of the details of the giant spacecraft are still to be worked out. But it's already clear that one of the most challenging aspects will be developing techniques to align and control these systems after they are deployed in space. A critical part of this process is creating new ground test methods to measure gossamer structures under stationary, deploying and vibrating conditions for validation of corresponding analytical predictions. In addressing this problem, I considered, first of all, the possibility of simply using conventional displacement or vibration sensor that could provide spatial measurements. Next, I turned my attention to photogrammetry, a method of determining the spatial coordinates of objects using photographs. The success of this research and development has convinced me that photogrammetry is the most suitable method to solve the gossamer measurement problem.

Structural design of an in-line bolted joint for the space shuttle solid rocket motor case segments

NASA Technical Reports Server (NTRS)

Dorsey, John T.; Stein, Peter A.; Bush, Harold G.

1987-01-01

Results of a structural design study of an in-line bolted joint concept which can be used to assemble Space Shuttle Solid Rocket Motor (SRM) case segments are presented. Numerous parametric studies are performed to characterize the in-line bolted joint behavior as major design variables are altered, with the primary objective always being to keep the inside of the joint (where the O-rings are located) closed during the SRM firing. The resulting design has 180 1-inch studs, an eccentricity of -0.5 inch, a flange thickness of 3/4 inch, a bearing plate thickness of 1/4 inch, and the studs are subjected to a preload which is 70% of ultimate. The mass penalty per case segment joint for the in-line design is 346 lbm more than the weight penalty for the proposed capture tang fix.

Hubble Space Telescope Fine Guidance Sensor interferometric observations of the core of 30 doradus

NASA Technical Reports Server (NTRS)

Lattanzi, M. G.; Hershey, J. L.; Burg, R.; Taff, L. G.; Holfeltz, S. T.; Bucciarelli, B.; Evans, I. N.; Gilmozzi, R.; Pringle, J.; Walborn, N. R.

1994-01-01

We present the results of the first high angular resolution observations taken with a Fine Guidance Sensor (FGS) aboard the Hubble Space Telescope (HST) of a star cluster embedded in very bright background. The strong and complex background around the R136 cluster in the 30 Dor nebula does not prevent the FGS from achieving performance close to its angular resolution limit of approximately 0.015 sec per axis with reliable photometry. These FGS observations establish that the central object in R136a is a triple star with the third component delta V = 1.1 mag fainter than the primary star al approximately 0.08 sec way. We estimate from the grid of models of Maeder (1990) that the present mass of al is between 30 and 80 solar masses, with the main-sequence progenitor between 60 and 120 solar masses.

Exploring the Structure of Spatial Representations

PubMed Central

Madl, Tamas; Franklin, Stan; Chen, Ke; Trappl, Robert; Montaldi, Daniela

2016-01-01

It has been suggested that the map-like representations that support human spatial memory are fragmented into sub-maps with local reference frames, rather than being unitary and global. However, the principles underlying the structure of these ‘cognitive maps’ are not well understood. We propose that the structure of the representations of navigation space arises from clustering within individual psychological spaces, i.e. from a process that groups together objects that are close in these spaces. Building on the ideas of representational geometry and similarity-based representations in cognitive science, we formulate methods for learning dissimilarity functions (metrics) characterizing participants’ psychological spaces. We show that these learned metrics, together with a probabilistic model of clustering based on the Bayesian cognition paradigm, allow prediction of participants’ cognitive map structures in advance. Apart from insights into spatial representation learning in human cognition, these methods could facilitate novel computational tools capable of using human-like spatial concepts. We also compare several features influencing spatial memory structure, including spatial distance, visual similarity and functional similarity, and report strong correlations between these dimensions and the grouping probability in participants’ spatial representations, providing further support for clustering in spatial memory. PMID:27347681

KSC-98pc621

NASA Image and Video Library

1998-05-19

Preliminary reports indicate the Space Shuttle's first super lightweight external tank (SLWT) is in excellent condition following the completion of a tanking test yesterday during a simulated launch countdown at Launch Pad 39A. The pad's Rotating Service Structure will be closed around Discovery later today as preparations for the STS-91 launch on June 2 continue. The primary objectives of the test were to evaluate the strut loads between the tank and the solid rocket boosters and to verify the integrity of the new components of the tank. The SLWT is 7,500 pounds lighter than its predecessors and was developed to increase the Shuttle payload capacity on International Space Station assembly flights. Major changes to the lighter tank include the use of new materials and a revised internal design. The new liquid oxygen and liquid hydrogen tanks are constructed of aluminum lithium a lighter, stronger material than the metal alloy currently used. The redesigned walls of the liquid hydrogen tank were machined to provide additional strength and stability, as well. The STS-91 mission will also feature the ninth Shuttle docking with the Russian Space Station Mir, the first Mir docking for Discovery, and the conclusion of Phase I of the joint U.S.-Russian International Space Station Program

KSC-98pc620

NASA Image and Video Library

1998-05-19

Preliminary reports indicate the Space Shuttle's first super lightweight external tank (SLWT) is in excellent condition following the completion of a tanking test yesterday during a simulated launch countdown at Launch Pad 39A. The pad's Rotating Service Structure will be closed around Discovery later today as preparations for the STS-91 launch on June 2 continue. The primary objectives of the test were to evaluate the strut loads between the tank and the solid rocket boosters and to verify the integrity of the new components of the tank. The SLWT is 7,500 pounds lighter than its predecessors and was developed to increase the Shuttle payload capacity on International Space Station assembly flights. Major changes to the lighter tank include the use of new materials and a revised internal design. The new liquid oxygen and liquid hydrogen tanks are constructed of aluminum lithium a lighter, stronger material than the metal alloy currently used. The redesigned walls of the liquid hydrogen tank were machined to provide additional strength and stability, as well. The STS-91 mission will also feature the ninth Shuttle docking with the Russian Space Station Mir, the first Mir docking for Discovery, and the conclusion of Phase I of the joint U.S.-Russian International Space Station Program

Stereovision-based pose and inertia estimation of unknown and uncooperative space objects

NASA Astrophysics Data System (ADS)

Pesce, Vincenzo; Lavagna, Michèle; Bevilacqua, Riccardo

2017-01-01

Autonomous close proximity operations are an arduous and attractive problem in space mission design. In particular, the estimation of pose, motion and inertia properties of an uncooperative object is a challenging task because of the lack of available a priori information. This paper develops a novel method to estimate the relative position, velocity, angular velocity, attitude and the ratios of the components of the inertia matrix of an uncooperative space object using only stereo-vision measurements. The classical Extended Kalman Filter (EKF) and an Iterated Extended Kalman Filter (IEKF) are used and compared for the estimation procedure. In addition, in order to compute the inertia properties, the ratios of the inertia components are added to the state and a pseudo-measurement equation is considered in the observation model. The relative simplicity of the proposed algorithm could be suitable for an online implementation for real applications. The developed algorithm is validated by numerical simulations in MATLAB using different initial conditions and uncertainty levels. The goal of the simulations is to verify the accuracy and robustness of the proposed estimation algorithm. The obtained results show satisfactory convergence of estimation errors for all the considered quantities. The obtained results, in several simulations, shows some improvements with respect to similar works, which deal with the same problem, present in literature. In addition, a video processing procedure is presented to reconstruct the geometrical properties of a body using cameras. This inertia reconstruction algorithm has been experimentally validated at the ADAMUS (ADvanced Autonomous MUltiple Spacecraft) Lab at the University of Florida. In the future, this different method could be integrated to the inertia ratios estimator to have a complete tool for mass properties recognition.

FLPP IXV Re-entry Vehicle, Transonic Characterisation Based on FOI T1500 Wind Tunnel Tests and CFD

NASA Astrophysics Data System (ADS)

Torngren, L.; Chiarelli, C.; Mareschi, V.; Tribot, J.-P.; Binetti, P.; Walloschek, T.

2009-01-01

The European Space Agency ESA, has engaged in 2004, the IXV project (Intermediate eXperimental Vehicle) which is part of the FLPP (Future Launcher Preparatory Programme) aiming at answering to critical technological issues, while supporting the future generation launchers and to improve in general European capabilities in the strategic field of atmospheric re-entry for space transportation, exploration and scientific applications. The IXV key mission and system objectives are the design, development, manufacturing, assembling and on-ground to in-flight verification of an autonomous European lifting and aerodynamically controlled re-entry system, integrating the critical re-entry technologies at the system level. The current IXV vehicle is a slender body type exhibiting rounded shape, thick body controlled by means of two control surfaces. The current mission is to perform an atmospheric re- entry ended by a safe recovery in supersonic regime. A potential extension of the flight domain down to the transonic regime was proposed to be analyzed. The objectives were to study the capability of the IXV for flying autonomously enabling a recovery of the vehicle by means of a subsonic parachute based DRS. The vehicle designed for the hypersonic speeds integrating a large base with only two control surfaces located close to the plane of symmetry is definitively not tuned for transonic ones. CFD done by Thales Alenia Space and wind tunnel activities involving FOI T1500 facility contributed to built up an Aerodynamic Data Base (AEDB) to be used as inputs for flying qualities analysis and re-entry simulations. The paper presents the main objectives of the transonic activities with emphasis on CFD and WTT including a description of the different prediction tools and discussing the main outcomes of the current data comparisons.

Gravitational Scattering Amplitudes and Closed String Field Theory in the Proper-Time Gauge

NASA Astrophysics Data System (ADS)

Lee, Taejin

2018-01-01

We construct a covariant closed string field theory by extending recent works on the covariant open string field theory in the proper-time gauge. Rewriting the string scattering amplitudes generated by the closed string field theory in terms of the Polyakov string path integrals, we identify the Fock space representations of the closed string vertices. We show that the Fock space representations of the closed string field theory may be completely factorized into those of the open string field theory. It implies that the well known Kawai-Lewellen-Tye (KLT) relations of the first quantized string theory may be promoted to the second quantized closed string theory. We explicitly calculate the scattering amplitudes of three gravitons by using the closed string field theory in the proper-time gauge.

Space Object Query Tool

NASA Technical Reports Server (NTRS)

Phillips, Veronica J.

2017-01-01

STI is for a fact sheet on the Space Object Query Tool being created by the MDC. When planning launches, NASA must first factor in the tens of thousands of objects already in orbit around the Earth. The number of human-made objects, including nonfunctional spacecraft, abandoned launch vehicle stages, mission-related debris and fragmentation debris orbiting Earth has grown steadily since Sputnik 1 was launched in 1957. Currently, the U.S. Department of Defenses Joint Space Operations Center, or JSpOC, tracks over 15,000 distinct objects and provides data for more than 40,000 objects via its Space-Track program, found at space-track.org.

Increasing airport capacity with modified IFR approach procedures for close-spaced parallel runways

DOT National Transportation Integrated Search

2001-01-01

Because of wake turbulence considerations, current instrument approach : procedures treat close-spaced (i.e., less than 2,500 feet apart) parallel run : ways as a single runway. This restriction is designed to assure safety for all : aircraft types u...

NEOCAM: Near Earth Object Chemical Analysis Mission: Bridging the Gulf between Telescopic Observations and the Chemical and Mineralogical Compositions of Asteroids or Diogenes A: Diagnostic Observation of the Geology of Near Earth Spectrally-Classified Asteroids

NASA Technical Reports Server (NTRS)

Nuth, Joseph A.

2009-01-01

Studies of meteorites have yielded a wealth of scientific information based on highly detailed chemical and isotopic studies possible only in sophisticated terrestrial laboratories. Telescopic studies have revealed an enormous (greater than 10(exp 5)) number of physical objects ranging in size from a few tens of meters to several hundred kilometers, orbiting not only in the traditional asteroid belt between Mars and Jupiter but also throughout the inner solar system. Many of the largest asteroids are classed into taxonomic groups based on their observed spectral properties and are designated as C, D. X, S or V types (as well as a wide range in sub-types). These objects are certainly the sources far the meteorites in our laboratories, but which asteroids are the sources for which meteorites? Spectral classes are nominally correlated to the chemical composition and physical characteristics of the asteroid itself based on studies of the spectral changes induced in meteorites due to exposure to a simulated space environment. While laboratory studies have produced some notable successes (e.g. the identification of the asteroid Vesta as the source of the H, E and D meteorite classes), it is unlikely that we have samples of each asteroidal spectral type in our meteorite collection. The correlation of spectral type and composition for many objects will therefore remain uncertain until we can return samples of specific asteroid types to Earth for analyses. The best candidates for sample return are asteroids that already come close to the Earth. Asteroids in orbit near 1 A.U. have been classified into three groups (Aten, Apollo & Amor) based on their orbital characteristics. These Near Earth Objects (NEOs) contain representatives of virtually all spectral types and sub-types of the asteroid population identified to date. Because of their close proximity to Earth, NEOs are prime targets for asteroid missions such as the NEAR-Shoemaker NASA Discovery Mission to Eros and the Japanese Hyabusa Mission to Itokawa. Also due to their close proximity to Earth, NEOs constitute the most likely set of celestial objects that will impact us in the relatively near future.

Spacecraft Guidance Strategies for Proximity Maneuvering and Close Approach with a Tumbling Object

DTIC Science & Technology

2010-03-01

R., and Junkins, J. L. (1984), ‘Optimal Open-Loop and Stable Feedback Control of Rigid Spacecraft Attitude Maneuvers ,’ The Journal of the... SPACECRAFT GUIDANCE STRATEGIES FOR PROXIMITY MANEUVERING AND CLOSE APPROACH WITH A TUMBLING OBJECT by George A. Boyarko March 2010...Dissertation 4. TITLE AND SUBTITLE: Spacecraft Guidance Strategies for Proximity Maneuvering and Close Approach with a Tumbling Object 6. AUTHOR

Critical issues related to registration of space objects and transparency of space activities

NASA Astrophysics Data System (ADS)

Jakhu, Ram S.; Jasani, Bhupendra; McDowell, Jonathan C.

2018-02-01

The main purpose of the 1975 Registration Convention is to achieve transparency in space activities and this objective is motivated by the belief that a mandatory registration system would assist in the identification of space objects launched into outer space. This would also consequently contribute to the application and development of international law governing the exploration and use of outer space. States Parties to the Convention furnish the required information to the United Nations' Register of Space Objects. However, the furnished information is often so general that it may not be as helpful in creating transparency as had been hoped by the drafters of the Convention. While registration of civil satellites has been furnished with some general details, till today, none of the Parties have described the objects as having military functions despite the fact that a large number of such objects do perform military functions as well. In some cases, the best they have done is to indicate that the space objects are for their defense establishments. Moreover, the number of registrations of space objects is declining. This paper addresses the challenges posed by the non-registration of space objects. Particularly, the paper provides some data about the registration and non-registration of satellites and the States that have and have not complied with their legal obligations. It also analyses the specific requirements of the Convention, the reasons for non-registration, new challenges posed by the registration of small satellites and the on-orbit transfer of satellites. Finally, the paper provides some recommendations on how to enhance the registration of space objects, on the monitoring of the implementation of the Registration Convention and consequently how to achieve maximum transparency in space activities.

Design of the deformable mirror demonstration CubeSat (DeMi)

NASA Astrophysics Data System (ADS)

Douglas, Ewan S.; Allan, Gregory; Barnes, Derek; Figura, Joseph S.; Haughwout, Christian A.; Gubner, Jennifer N.; Knoedler, Alex A.; LeClair, Sarah; Murphy, Thomas J.; Skouloudis, Nikolaos; Merck, John; Opperman, Roedolph A.; Cahoy, Kerri L.

2017-09-01

The Deformable Mirror Demonstration Mission (DeMi) was recently selected by DARPA to demonstrate in-space operation of a wavefront sensor and Microelectromechanical system (MEMS) deformable mirror (DM) payload on a 6U CubeSat. Space telescopes designed to make high-contrast observations using internal coronagraphs for direct characterization of exoplanets require the use of high-actuator density deformable mirrors. These DMs can correct image plane aberrations and speckles caused by imperfections, thermal distortions, and diffraction in the telescope and optics that would otherwise corrupt the wavefront and allow leaking starlight to contaminate coronagraphic images. DeMi is provide on-orbit demonstration and performance characterization of a MEMS deformable mirror and closed loop wavefront sensing. The DeMi payload has two operational modes, one mode that images an internal light source and another mode which uses an external aperture to images stars. Both the internal and external modes include image plane and pupil plane wavefront sensing. The objectives of the internal measurement of the 140-actuator MEMS DM actuator displacement are characterization of the mirror performance and demonstration of closed-loop correction of aberrations in the optical path. Using the external aperture to observe stars of magnitude 2 or brighter, assuming 3-axis stability with less than 0.1 degree of attitude knowledge and jitter below 10 arcsec RMSE, per observation, DeMi will also demonstrate closed loop wavefront control on an astrophysical target. We present an updated payload design, results from simulations and laboratory optical prototyping, as well as present our design for accommodating high-voltage multichannel drive electronics for the DM on a CubeSat.

Extending peripersonal space representation without tool-use: evidence from a combined behavioral-computational approach

PubMed Central

Serino, Andrea; Canzoneri, Elisa; Marzolla, Marilena; di Pellegrino, Giuseppe; Magosso, Elisa

2015-01-01

Stimuli from different sensory modalities occurring on or close to the body are integrated in a multisensory representation of the space surrounding the body, i.e., peripersonal space (PPS). PPS dynamically modifies depending on experience, e.g., it extends after using a tool to reach far objects. However, the neural mechanism underlying PPS plasticity after tool use is largely unknown. Here we use a combined computational-behavioral approach to propose and test a possible mechanism accounting for PPS extension. We first present a neural network model simulating audio-tactile representation in the PPS around one hand. Simulation experiments showed that our model reproduced the main property of PPS neurons, i.e., selective multisensory response for stimuli occurring close to the hand. We used the neural network model to simulate the effects of a tool-use training. In terms of sensory inputs, tool use was conceptualized as a concurrent tactile stimulation from the hand, due to holding the tool, and an auditory stimulation from the far space, due to tool-mediated action. Results showed that after exposure to those inputs, PPS neurons responded also to multisensory stimuli far from the hand. The model thus suggests that synchronous pairing of tactile hand stimulation and auditory stimulation from the far space is sufficient to extend PPS, such as after tool-use. Such prediction was confirmed by a behavioral experiment, where we used an audio-tactile interaction paradigm to measure the boundaries of PPS representation. We found that PPS extended after synchronous tactile-hand stimulation and auditory-far stimulation in a group of healthy volunteers. Control experiments both in simulation and behavioral settings showed that the same amount of tactile and auditory inputs administered out of synchrony did not change PPS representation. We conclude by proposing a simple, biological-plausible model to explain plasticity in PPS representation after tool-use, which is supported by computational and behavioral data. PMID:25698947

Extending peripersonal space representation without tool-use: evidence from a combined behavioral-computational approach.

PubMed

Serino, Andrea; Canzoneri, Elisa; Marzolla, Marilena; di Pellegrino, Giuseppe; Magosso, Elisa

2015-01-01

Stimuli from different sensory modalities occurring on or close to the body are integrated in a multisensory representation of the space surrounding the body, i.e., peripersonal space (PPS). PPS dynamically modifies depending on experience, e.g., it extends after using a tool to reach far objects. However, the neural mechanism underlying PPS plasticity after tool use is largely unknown. Here we use a combined computational-behavioral approach to propose and test a possible mechanism accounting for PPS extension. We first present a neural network model simulating audio-tactile representation in the PPS around one hand. Simulation experiments showed that our model reproduced the main property of PPS neurons, i.e., selective multisensory response for stimuli occurring close to the hand. We used the neural network model to simulate the effects of a tool-use training. In terms of sensory inputs, tool use was conceptualized as a concurrent tactile stimulation from the hand, due to holding the tool, and an auditory stimulation from the far space, due to tool-mediated action. Results showed that after exposure to those inputs, PPS neurons responded also to multisensory stimuli far from the hand. The model thus suggests that synchronous pairing of tactile hand stimulation and auditory stimulation from the far space is sufficient to extend PPS, such as after tool-use. Such prediction was confirmed by a behavioral experiment, where we used an audio-tactile interaction paradigm to measure the boundaries of PPS representation. We found that PPS extended after synchronous tactile-hand stimulation and auditory-far stimulation in a group of healthy volunteers. Control experiments both in simulation and behavioral settings showed that the same amount of tactile and auditory inputs administered out of synchrony did not change PPS representation. We conclude by proposing a simple, biological-plausible model to explain plasticity in PPS representation after tool-use, which is supported by computational and behavioral data.

Electric fish as natural models for technical sensor systems

NASA Astrophysics Data System (ADS)

von der Emde, Gerhard; Bousack, Herbert; Huck, Christina; Mayekar, Kavita; Pabst, Michael; Zhang, Yi

2009-05-01

Instead of vision, many animals use alternative senses for object detection. Weakly electric fish employ "active electrolocation", during which they discharge an electric organ emitting electrical current pulses (electric organ discharges, EOD). Local EODs are sensed by electroreceptors in the fish's skin, which respond to changes of the signal caused by nearby objects. Fish can gain information about attributes of an object, such as size, shape, distance, and complex impedance. When close to the fish, each object projects an 'electric image' onto the fish's skin. In order to get information about an object, the fish has to analyze the object's electric image by sampling its voltage distribution with the electroreceptors. We now know a great deal about the mechanisms the fish use to gain information about objects in their environment. Inspired by the remarkable capabilities of weakly electric fish in detecting and recognizing objects with their electric sense, we are designing technical sensor systems that can solve similar sensing problems. We applied the principles of active electrolocation to devices that produce electrical current pulses in water and simultaneously sense local current densities. Depending on the specific task, sensors can be designed which detect an object, localize it in space, determine its distance, and measure certain object properties such as material properties, thickness, or material faults. We present first experiments and FEM simulations on the optimal sensor arrangement regarding the sensor requirements e. g. localization of objects or distance measurements. Different methods of the sensor read-out and signal processing are compared.

From fields to objects: A review of geographic boundary analysis

NASA Astrophysics Data System (ADS)

Jacquez, G. M.; Maruca, S.; Fortin, M.-J.

Geographic boundary analysis is a relatively new approach unfamiliar to many spatial analysts. It is best viewed as a technique for defining objects - geographic boundaries - on spatial fields, and for evaluating the statistical significance of characteristics of those boundary objects. This is accomplished using null spatial models representative of the spatial processes expected in the absence of boundary-generating phenomena. Close ties to the object-field dialectic eminently suit boundary analysis to GIS data. The majority of existing spatial methods are field-based in that they describe, estimate, or predict how attributes (variables defining the field) vary through geographic space. Such methods are appropriate for field representations but not object representations. As the object-field paradigm gains currency in geographic information science, appropriate techniques for the statistical analysis of objects are required. The methods reviewed in this paper are a promising foundation. Geographic boundary analysis is clearly a valuable addition to the spatial statistical toolbox. This paper presents the philosophy of, and motivations for geographic boundary analysis. It defines commonly used statistics for quantifying boundaries and their characteristics, as well as simulation procedures for evaluating their significance. We review applications of these techniques, with the objective of making this promising approach accessible to the GIS-spatial analysis community. We also describe the implementation of these methods within geographic boundary analysis software: GEM.

The Impact Imperative: A Space Infrastructure Enabling a Multi-Tiered Earth Defense

NASA Technical Reports Server (NTRS)

Campbell, Jonathan W.; Phipps, Claude; Smalley, Larry; Reilly, James; Boccio, Dona

2003-01-01

Impacting at hypervelocity, an asteroid struck the Earth approximately 65 million years ago in the Yucatan Peninsula a m . This triggered the extinction of almost 70% of the species of life on Earth including the dinosaurs. Other impacts prior to this one have caused even greater extinctions. Preventing collisions with the Earth by hypervelocity asteroids, meteoroids, and comets is the most important immediate space challenge facing human civilization. This is the Impact Imperative. We now believe that while there are about 2000 earth orbit crossing rocks greater than 1 kilometer in diameter, there may be as many as 200,000 or more objects in the 100 m size range. Can anything be done about this fundamental existence question facing our civilization? The answer is a resounding yes! By using an intelligent combination of Earth and space based sensors coupled with an infrastructure of high-energy laser stations and other secondary mitigation options, we can deflect inbound asteroids, meteoroids, and comets and prevent them &om striking the Earth. This can be accomplished by irradiating the surface of an inbound rock with sufficiently intense pulses so that ablation occurs. This ablation acts as a small rocket incrementally changing the shape of the rock's orbit around the Sun. One-kilometer size rocks can be moved sufficiently in about a month while smaller rocks may be moved in a shorter time span. We recommend that space objectives be immediately reprioritized to start us moving quickly towards an infrastructure that will support a multiple option defense capability. Planning and development for a lunar laser facility should be initiated immediately in parallel with other options. All mitigation options are greatly enhanced by robust early warning, detection, and tracking resources to find objects sufficiently prior to Earth orbit passage in time to allow significant intervention. Infrastructure options should include ground, LEO, GEO, Lunar, and libration point laser and sensor stations for providing early warning, tracking, and deflection. Other options should include space interceptors that will carry both laser and nuclear ablators for close range work. Response options must be developed to deal with the consequences of an impact should we move too slowly.

An Internet Protocol-Based Software System for Real-Time, Closed-Loop, Multi-Spacecraft Mission Simulation Applications

NASA Technical Reports Server (NTRS)

Davis, George; Cary, Everett; Higinbotham, John; Burns, Richard; Hogie, Keith; Hallahan, Francis

2003-01-01

The paper will provide an overview of the web-based distributed simulation software system developed for end-to-end, multi-spacecraft mission design, analysis, and test at the NASA Goddard Space Flight Center (GSFC). This software system was developed for an internal research and development (IR&D) activity at GSFC called the Distributed Space Systems (DSS) Distributed Synthesis Environment (DSE). The long-term goal of the DSS-DSE is to integrate existing GSFC stand-alone test beds, models, and simulation systems to create a "hands on", end-to-end simulation environment for mission design, trade studies and simulations. The short-term goal of the DSE was therefore to develop the system architecture, and then to prototype the core software simulation capability based on a distributed computing approach, with demonstrations of some key capabilities by the end of Fiscal Year 2002 (FY02). To achieve the DSS-DSE IR&D objective, the team adopted a reference model and mission upon which FY02 capabilities were developed. The software was prototyped according to the reference model, and demonstrations were conducted for the reference mission to validate interfaces, concepts, etc. The reference model, illustrated in Fig. 1, included both space and ground elements, with functional capabilities such as spacecraft dynamics and control, science data collection, space-to-space and space-to-ground communications, mission operations, science operations, and data processing, archival and distribution addressed.

Subjective time in near and far representational space.

PubMed

Zäch, Peter; Brugger, Peter

2008-03-01

We set out to measure healthy subjects' estimates of temporal duration during the imagination of left and right sides of an object located in either near or far representational space. Duration estimates during the observation of small-scale scenes are shorter than those during the observation of the same scenes presented in a larger scale. It is not known whether a similar space-time relationship also exists for objects merely imagined and whether subjective time varies with a forced focus on either the left or the right side of a mental image. Eyes closed, 40 healthy, right-handed subjects (20 women) had to imagine a standard Swiss railway clock either at a distance of 30 cm or 6 m. They were required to focus on the imagined movement of the second hand and provide estimates of elapsed durations of 15 and 30 seconds. Separate estimates for the left and right side of the clockface were obtained. The magnitude of implicit line bisection error was assessed in a separate task. Irrespective of side of the clockface, duration estimates were shorter for the clockface imagined in far space than for the one imagined immediately in front of the inner eye. For men, but not women, duration judgments (left relative to right side of the clockface) correlated with relative lengths of left and right line segments in the bisection task. Subjective time seems to run faster during the inspection of a small-size compared with a larger-size mental image. This finding underlines the equivalence of the laws that guide both exploration and representation of space. Together with the observed correlation between spatial and temporal measures of lateral asymmetries, the result also illustrates the conceptual similarities in the processing of space and time. The normative data presented here may be useful for clinical applications of the paradigm in patients with hemispatial neglect or a distorted perception of time.

Verification of Space Weather Forecasts using Terrestrial Weather Approaches

NASA Astrophysics Data System (ADS)

Henley, E.; Murray, S.; Pope, E.; Stephenson, D.; Sharpe, M.; Bingham, S.; Jackson, D.

2015-12-01

The Met Office Space Weather Operations Centre (MOSWOC) provides a range of 24/7 operational space weather forecasts, alerts, and warnings, which provide valuable information on space weather that can degrade electricity grids, radio communications, and satellite electronics. Forecasts issued include arrival times of coronal mass ejections (CMEs), and probabilistic forecasts for flares, geomagnetic storm indices, and energetic particle fluxes and fluences. These forecasts are produced twice daily using a combination of output from models such as Enlil, near-real-time observations, and forecaster experience. Verification of forecasts is crucial for users, researchers, and forecasters to understand the strengths and limitations of forecasters, and to assess forecaster added value. To this end, the Met Office (in collaboration with Exeter University) has been adapting verification techniques from terrestrial weather, and has been working closely with the International Space Environment Service (ISES) to standardise verification procedures. We will present the results of part of this work, analysing forecast and observed CME arrival times, assessing skill using 2x2 contingency tables. These MOSWOC forecasts can be objectively compared to those produced by the NASA Community Coordinated Modelling Center - a useful benchmark. This approach cannot be taken for the other forecasts, as they are probabilistic and categorical (e.g., geomagnetic storm forecasts give probabilities of exceeding levels from minor to extreme). We will present appropriate verification techniques being developed to address these forecasts, such as rank probability skill score, and comparing forecasts against climatology and persistence benchmarks. As part of this, we will outline the use of discrete time Markov chains to assess and improve the performance of our geomagnetic storm forecasts. We will also discuss work to adapt a terrestrial verification visualisation system to space weather, to help MOSWOC forecasters view verification results in near real-time; plans to objectively assess flare forecasts under the EU Horizon 2020 FLARECAST project; and summarise ISES efforts to achieve consensus on verification.

Modeling and control of a flexible space robot to capture a tumbling debris

NASA Astrophysics Data System (ADS)

Dubanchet, Vincent

After 60 years of intensive satellite launches, the number of drifting objects in Earth orbits is reaching a shifting point, where human intervention is becoming necessary to reduce the threat of collision. Indeed, a 200 year forecast, known as the "Kessler syndrome", states that space access will be greatly compromised if nothing is done to address the proliferation of these debris. Scientist J.-C. Liou from the National Aeronautics and Space Administration (NASA) has shown that the current trend could be reversed if at least five massive objects, such as dead satellites or rocket upper stages, were de-orbited each year. Among the various technical concepts considered for debris removal, robotics has emerged, over the last 30 years, as one of the most promising solutions. The International Space Station (ISS) already possesses fully operational robotic arms, and other missions have explored the potential of a manipulator embedded onto a satellite. During two of the latter, key capabilities have been demonstrated for on-orbit servicing, and prove to be equally useful for the purpose of debris removal. This thesis focuses on the close range capture of a tumbling debris by a robotic arm with light-weight flexible segments. This phase includes the motion planning and the control of a space robot, in order to smoothly catch a target point on the debris. The validation of such technologies is almost impossible on Earth and leads to prohibitive costs when performed on orbit. Therefore, the modeling and simulation of flexible multi-body systems has been investigated thoroughly, and is likewise a strong contribution of the thesis. Based on these models, an experimental validation is proposed by reproducing the on-orbit kinematics on a test bench made up of two industrial manipulators and driven by a real-time dynamic simulation. In a nutshell, the thesis is built around three main parts: the modeling of a space robot, the design of control laws, and their validation on a test case. (Abstract shortened by ProQuest.).

Field testing and implementation of dilemma zone protection and signal coordination at closely-spaced high-speed intersections : final report, May 19, 2005.

DOT National Transportation Integrated Search

2005-05-01

The report presents the details of a study carried out to test and implement a dilemma zone protection technique at three high-speed closely-spaced intersections on Roosevelt Blvd in Middletown, Ohio.

Exploring the Role of Space-Defining Objects in Constructing and Maintaining Imagined Scenes

ERIC Educational Resources Information Center

Mullally, Sinead L.; Maguire, Eleanor A.

2013-01-01

It has recently been observed that certain objects, when viewed or imagined in isolation, evoke a strong sense of three-dimensional local space surrounding them (space-defining (SD) objects), while others do not (space-ambiguous (SA) objects), and this is associated with engagement of the parahippocampal cortex (PHC). But activation of the PHC is…

The STIS MAMA status: Current detector performance

NASA Technical Reports Server (NTRS)

Danks, A. C.; Joseph, C.; Bybee, R.; Argebright, V.; Abraham, J.; Kimble, R.; Woodgate, B.

1992-01-01

The STIS (Space Telescope Imaging Spectrograph) is a second generation Hubble instrument scheduled to fly in 1997. Through a variety of modes, the instrument will provide spectral resolutions from R approximately 50 in the objective spectroscopy mode to 100,000 in the high resolution echelle mode in the wavelength region from 115 to 1000 nm. In the UV the instrument employs two MAMA (Multimode Anode Microchannel plate Arrays) 1024 by 1024 pixel detectors, which provide high DQE (Detective Quantum Efficiency), and good dynamic range and resolution. The current progress and performance of these detectors are reported, illustrating that the technology is mature and that the performance is very close to flight requirements.

Efficient dynamic simulation for multiple chain robotic mechanisms

NASA Technical Reports Server (NTRS)

Lilly, Kathryn W.; Orin, David E.

1989-01-01

An efficient O(mN) algorithm for dynamic simulation of simple closed-chain robotic mechanisms is presented, where m is the number of chains, and N is the number of degrees of freedom for each chain. It is based on computation of the operational space inertia matrix (6 x 6) for each chain as seen by the body, load, or object. Also, computation of the chain dynamics, when opened at one end, is required, and the most efficient algorithm is used for this purpose. Parallel implementation of the dynamics for each chain results in an O(N) + O(log sub 2 m+1) algorithm.

Self-contained exothermic applicator and process

DOEpatents

Koehmstedt, Paul L.

1984-01-01

An adhesive resin application system which requires no external heating apparatus, and which is operative in the absence of a reactive atmosphere, is disclosed. The system provides its own heat by employing an adhesive material containing reactants which react exothermally when electrically ignited. After ignition of the reactants, sufficient heat energy is liberated by the exothermic reaction either to plasticize a thermoplastic resin or to cure a thermosetting resin and therby bond together two closely spaced objects. This application is a continuation-in-part of application Ser. No. 489,006, filed Apr. 27, 1983, which is a continuation-in-part of application, Ser. No. 929,120, filed July 28, 1978, both now abandoned.

Challenges in Physical Characterization of Dim Space Objects: What Can We Learn from NEOs

NASA Astrophysics Data System (ADS)

Reddy, V.; Sanchez, J.; Thirouin, A.; Rivera-Valentin, E.; Ryan, W.; Ryan, E.; Mokovitz, N.; Tegler, S.

2016-09-01

Physical characterization of dim space objects in cis-lunar space can be a challenging task. Of particular interest to both natural and artificial space object behavior scientists are the properties beyond orbital parameters that can uniquely identify them. These properties include rotational state, size, shape, density and composition. A wide range of observational and non-observational factors affect our ability to characterize dim objects in cis-lunar space. For example, phase angle (angle between Sun-Target-Observer), temperature, rotational variations, temperature, and particle size (for natural dim objects). Over the last two decades, space object behavior scientists studying natural dim objects have attempted to quantify and correct for a majority of these factors to enhance our situational awareness. These efforts have been primarily focused on developing laboratory spectral calibrations in a space-like environment. Calibrations developed correcting spectral observations of natural dim objects could be applied to characterizing artificial objects, as the underlying physics is the same. The paper will summarize our current understanding of these observational and non-observational factors and present a case study showcasing the state of the art in characterization of natural dim objects.

STS-101: Flight Day Highlights / CAR

NASA Technical Reports Server (NTRS)

2000-01-01

The primary mission objective for STS-101 was to deliver supplies to the International Space Station, perform a space walk, and reboost the station from 230 statute miles to 250 statute miles. The commander of this mission was, James D. Halsell. The crew was Scott J. Horowitz, the pilot, and mission specialists Mary Ellen Weber, Jeffrey N. Williams, James S. Voss, Susan J. Helms, and Yuri Vladimirovich Usachev. This videotape shows the launch of STS-101, beginning with the pre-flight breakfast and the crew's introduction. The videotape next shows a pre-dawn view of the orbiter waiting the crew's arrival. The crew is shown getting into their space suits and then climbing onboard the shuttle. In this videotape we are shown a few of the crew getting into their places onboard the shuttle. We are also shown the newly designed "glass cockpit", which gives the pilot and the commander better views and are told that this is the first flight of the shuttle with the new design. After the hatch is closed, we see the shuttle launch into the night, followed by the Solid Rocket Boosters (SRB) separation.

Assessment of the Microbial Control Measures for the Temperature and Humidity Control Subsystem Condensing Heat Exchanger of the International Space Station

NASA Technical Reports Server (NTRS)

Roman, Monsi C.; Steele, John W.; Marsh, Robert W.; Callahan, David M.; VonJouanne, Roger G.

1999-01-01

In August 1997 NASA/ Marshall Space Flight Center (MSFC) began a test with the objective of monitoring the growth of microorganisms on material simulating the surface of the International Space Station (ISS) Temperature and Humidity Control (THC) Condensing Heat Exchanger (CHX). The test addressed the concerns of potential uncontrolled microbial growth on the surface of the THC CHX subsystem. For this study, humidity condensate from a closed manned environment was used as a direct challenge to the surfaces of six cascades in a test set-up. The condensate was collected using a Shuttle-type CHX within the MSFC End-Use Equipment Testing Facility. Panels in four of the six cascades tested were coated with the ISS CHX silver impregnated hydrophilic coating. The remainder two cascade panels were coated with the hydrophilic coating without the antimicrobial component, silver. Results of the fourteen-month study are discussed in this paper. The effects on the microbial population when drying vs. not-drying the simulated THC CHX surface are also discussed.

KSC-07pd2213

NASA Image and Video Library

2007-08-03

KENNEDY SPACE CENTER, FLA. - In Orbiter Processing Facility bay 3, STS-120 crew members get a close look at hardware in Discovery's payload bay. In the bucket at left is Mission Specialist Paolo A. Nespoli, who is a European Space Agency astronaut from Italy. The object with the shiny gold surface is a payload bay bulkhead camera. The STS-120 crew is at Kennedy for a crew equipment interface test, or CEIT, which includes harness training, inspection of the thermal protection system and camera operation for planned extravehicular activities, or EVAs. The STS-120 mission will deliver the Harmony module, christened after a school contest, which will provide attachment points for European and Japanese laboratory modules on the International Space Station. Known in technical circles as Node 2, it is similar to the six-sided Unity module that links the U.S. and Russian sections of the station. Built in Italy for the United States, Harmony will be the first new U.S. pressurized component to be added. The STS-120 mission is targeted to launch on Oct. 20. Photo credit: NASA/George Shelton

Simulation analysis of photometric data for attitude estimation of unresolved space objects

NASA Astrophysics Data System (ADS)

Du, Xiaoping; Gou, Ruixin; Liu, Hao; Hu, Heng; Wang, Yang

2017-10-01

The attitude information acquisition of unresolved space objects, such as micro-nano satellites and GEO objects under the way of ground-based optical observations, is a challenge to space surveillance. In this paper, a useful method is proposed to estimate the SO attitude state according to the simulation analysis of photometric data in different attitude states. The object shape model was established and the parameters of the BRDF model were determined, then the space object photometric model was established. Furthermore, the photometric data of space objects in different states are analyzed by simulation and the regular characteristics of the photometric curves are summarized. The simulation results show that the photometric characteristics are useful for attitude inversion in a unique way. Thus, a new idea is provided for space object identification in this paper.

In-Vacuum Photogrammetry of a 10-Meter Solar Sail

NASA Technical Reports Server (NTRS)

Meyer, Chris G.; Jones, Thomas W.; Lunsford, Charles B.; Pappa, Richard S.

2005-01-01

In July 2004, a 10-meter solar sail structure developed by L Garde, Inc. was tested in vacuum at the NASA Glenn 30-meter Plum Brook Space Power Facility in Sandusky, Ohio. The three main objections of the test were to demonstrate unattended deployment from a stowed configuration, to measure the deployed shape of the sail at both ambient and cryogenic room temperatures, and to measure the deployed structural dynamic characteristics (vibration modes). This paper summarizes the work conducted to fulfill the second test objective. The deployed shape was measured photogrammetrically in vacuum conditions with four 2-megapixel digital video cameras contained in custom made pressurized canisters. The canisters included high-intensity LED ring lights to illuminate a grid of retroreflective targets distributed on the solar sail. The test results closely matched pre-test photogrammetry numerical simulations and compare well with ABAQUS finite-element model predictions.

Robust decentralized control laws for the ACES structure

NASA Technical Reports Server (NTRS)

Collins, Emmanuel G., Jr.; Phillips, Douglas J.; Hyland, David C.

1991-01-01

Control system design for the Active Control Technique Evaluation for Spacecraft (ACES) structure at NASA Marshall Space Flight Center is discussed. The primary objective of this experiment is to design controllers that provide substantial reduction of the line-of-sight pointing errors. Satisfaction of this objective requires the controllers to attenuate beam vibration significantly. The primary method chosen for control design is the optimal projection approach for uncertain systems (OPUS). The OPUS design process allows the simultaneous tradeoff of five fundamental issues in control design: actuator sizing, sensor accuracy, controller order, robustness, and system performance. A brief description of the basic ACES configuration is given. The development of the models used for control design and control design for eight system loops that were selected by analysis of test data collected from the structure are discussed. Experimental results showing that very significant performance improvement is achieved when all eight feedback loops are closed are presented.

A catalog of low surface brightness galaxies - List II

NASA Technical Reports Server (NTRS)

Schombert, James M.; Bothun, Gregory D.; Schneider, Stephen E.; Mcgaugh, Stacy S.

1992-01-01

A list of galaxies characterized by low surface brightness (LSB) is presented which facilitates the recognition of galaxies with brightnesses close to that of the sky. A total of 198 objects and 140 objects are listed in the primary and secondary catalogs respectively, and LSB galaxies are examined by means of H I redshift distributions. LSB disk galaxies are shown to have similar sizes and masses as the high-surface-brightness counterparts, and ellipticals and SOs are rarely encountered. Many LSB spirals have stellarlike nuclei, and most of the galaxies in the present catalog are late-type galaxies in the Sc, Sm, and Im classes. The LSB region of observational parameter space is shown to encompass a spectrum of types as full as that of the Hubble sequence. It is suggested that studies of LSB galaxies can provide important data regarding the formation and star-formation history of all galaxies.

An Electric Propulsion "Shepherd" for Active Debris Removal that Utilizes Ambient Gas as Propellant

NASA Technical Reports Server (NTRS)

Matney, Mark J.

2013-01-01

There is a growing consensus among the space debris technical community that limiting the long ]term growth of debris in Low-Earth Orbit (LEO) requires that space users limit the accumulation of mass in orbit. This is partially accomplished by mitigation measures for current and future LEO systems, but there is now interest in removing mass that has already accumulated in LEO from more than 50 years of space activity (termed "Active Debris Removal", or ADR). Many ADR proposals face complex technical issues of how to grapple with uncooperative targets. Some researchers have suggested the use of conventional ion thrusters to gently "blow" on objects to gradually change their orbits, without ever having to come into physical contact with the target. The chief drawback with these methods is the cost per object removed. Typically, a space "tug" or an ion-drive "shepherd" can only remove a few objects per mission due to limited propellant. Unless a costeffective way that removes tens of objects per mission can be found, it is not clear that any of the ideas so far proposed will be economically viable. In this paper, a modified version of the ion-drive "shepherd" is proposed that uses ambient atmospheric gases in LEO as propellant for the ion drives. This method has the potential to greatly extend the operational lifetime of an ADR mission, as the only mission limit is the lifetime of the components of the satellite itself, not on its fuel supply. An ambient-gas ion-drive "shepherd" would the local atmospheric drag on an object by ionizing and accelerating the ambient gas the target would have encountered anyway, thereby hastening its decay. Also, the "shepherd" satellite itself has a great deal of flexibility to maneuver back to high altitude and rendezvous with its next target using the ion drive not limited by fuel supply. However, the amount of available ambient gas is closely tied to the altitude of the spacecraft. It may be possible to use a "hybrid" approach that supplements high-altitude ion-drive operations with stored gas, and transitions to ambient gas at lower altitudes. This paper will include realistic numbers on the estimated times needed to deorbit objects from different orbit regimes using drives that either partially or completely take advantage of ambient gas. It will conclude with recommendations on whether this is a viable candidate for future ADR efforts.

An Electric Propulsion "Shepherd" for Active Debris Removal that Utilizes Ambient Gas as Propellant

NASA Technical Reports Server (NTRS)

Matney, Mark

2013-01-01

There is a growing consensus among the space debris technical community that limiting the long-term growth of debris in Low-Earth Orbit (LEO) requires that space users limit the accumulation of mass in orbit. This is partially accomplished by mitigation measures for current and future LEO systems, but there is now interest in removing mass that has already accumulated in LEO from more than 50 years of space activity (termed "Active Debris Removal", or ADR). Many ADR proposals face complex technical issues of how to grapple with uncooperative targets. Some researchers have suggested the use of conventional ion thrusters to gently "blow" on objects to gradually change their orbits, without ever having to come into physical contact with the target. The chief drawback with these methods is the cost per object removed. Typically, a space "tug" or an ion-drive "shepherd" can only remove a few objects per mission due to limited propellant. Unless a cost-effective way that removes tens of objects per mission can be found, it is not clear that any of the ideas so far proposed will be economically viable. In this paper, a modified version of the ion-drive "shepherd" is proposed that uses ambient atmospheric gases in LEO as propellant for the ion drives. This method has the potential to greatly extend the operational lifetime of an ADR mission, as the only mission limit is the lifetime of the components of the satellite itself, not on its fuel supply. An ambient-gas ion-drive "shepherd" would enhance the local atmospheric drag on an object by ionizing and accelerating the ambient gas the target would have encountered anyway, thereby hastening its decay. Also, the "shepherd" satellite itself has a great deal of flexibility to maneuver back to high altitude and rendezvous with its next target using the ion drive not limited by fuel supply. However, the amount of available ambient gas is closely tied to the altitude of the spacecraft. It may be possible to use a "hybrid" approach that supplements high-altitude ion-drive operations with stored gas, and transitions to ambient gas at lower altitudes. This paper will include realistic numbers on the estimated times needed to deorbit objects from different orbit regimes using drives that either partially or completely take advantage of ambient gas. It will conclude with recommendations on whether this is a viable candidate for future ADR efforts.

Object-based warping: an illusory distortion of space within objects.

PubMed

Vickery, Timothy J; Chun, Marvin M

2010-12-01

Visual objects are high-level primitives that are fundamental to numerous perceptual functions, such as guidance of attention. We report that objects warp visual perception of space in such a way that spatial distances within objects appear to be larger than spatial distances in ground regions. When two dots were placed inside a rectangular object, they appeared farther apart from one another than two dots with identical spacing outside of the object. To investigate whether this effect was object based, we measured the distortion while manipulating the structure surrounding the dots. Object displays were constructed with a single object, multiple objects, a partially occluded object, and an illusory object. Nonobject displays were constructed to be comparable to object displays in low-level visual attributes. In all cases, the object displays resulted in a more powerful distortion of spatial perception than comparable non-object-based displays. These results suggest that perception of space within objects is warped.

Space station systems analysis study. Part 1, volume 1: Executive study

NASA Technical Reports Server (NTRS)

1976-01-01

Potential space station system options were examined for a permanent, manned, orbital space facility and to provide data to NASA program planners and decision makers for their use in future program planning. There were ten space station system objectives identified. These were categorized into five major objectives and five supporting objectives. The major objectives were to support the development of: (1) satellite power systems, (2) nuclear energy plants in space, (3) space processing, (4) earth services, and (5) space cosmological research and development. The five supporting objectives, to define space facilities which would be basic building blocks for future systems, were: (1) a multidiscipline science laboratory, (2) an orbital depot to maintain, fuel, and service orbital transfer vehicles, (3) cluster support systems to provide power and data processing for multiple orbital elements, (4) a sensor development facility, and (5) the facilities necessary to enhance man's living and working in space.

A Preliminary Research Plan for Development of a Photosynthetic Link in a Closed Ecological Life Support System

NASA Technical Reports Server (NTRS)

Morgan, P. W.

1979-01-01

The use of higher plants in a closed ecological life support system for long duration space missions involving large numbers of people is considered. The approach to planning and developing both the habitat for a long term space mission and closed ecological life support systems are discussed with emphasis on environmental compatibility and integrated systems design. The requirements of photosynthetic processes are summarized and evaluated in terms of their availability within a closed ecological life support environment. Specific references are recommended as a data base for future research on this topic.

Proximity Operations for Space Situational Awareness Spacecraft Rendezvous and Maneuvering using Numerical Simulations and Fuzzy Logic

NASA Astrophysics Data System (ADS)

Carrico, T.; Langster, T.; Carrico, J.; Alfano, S.; Loucks, M.; Vallado, D.

The authors present several spacecraft rendezvous and close proximity maneuvering techniques modeled with a high-precision numerical integrator using full force models and closed loop control with a Fuzzy Logic intelligent controller to command the engines. The authors document and compare the maneuvers, fuel use, and other parameters. This paper presents an innovative application of an existing capability to design, simulate and analyze proximity maneuvers; already in use for operational satellites performing other maneuvers. The system has been extended to demonstrate the capability to develop closed loop control laws to maneuver spacecraft in close proximity to another, including stand-off, docking, lunar landing and other operations applicable to space situational awareness, space based surveillance, and operational satellite modeling. The fully integrated end-to-end trajectory ephemerides are available from the authors in electronic ASCII text by request. The benefits of this system include: A realistic physics-based simulation for the development and validation of control laws A collaborative engineering environment for the design, development and tuning of spacecraft law parameters, sizing actuators (i.e., rocket engines), and sensor suite selection. An accurate simulation and visualization to communicate the complexity, criticality, and risk of spacecraft operations. A precise mathematical environment for research and development of future spacecraft maneuvering engineering tasks, operational planning and forensic analysis. A closed loop, knowledge-based control example for proximity operations. This proximity operations modeling and simulation environment will provide a valuable adjunct to programs in military space control, space situational awareness and civil space exploration engineering and decision making processes.

Registration of Space Objects

NASA Astrophysics Data System (ADS)

Schmidt-Tedd, Bernhard

2017-07-01

Space objects are subject to registration in order to allocate "jurisdiction and control" over those objects in the sovereign-free environment of outer space. This approach is similar to the registration of ships in view of the high sea and for aircrafts with respect to the international airspace. Registration is one of the basic principles of space law, starting with UN General Assembly Resolution 1721 B (XVI) of December 20, 1961, followed by Resolution 1962 (XVIII) of December 13, 1963, then formulated in Article VIII of the Outer Space Treaty of 1967 and as specified in the Registration Convention of 1975. Registration of space objects can be seen today as a principle of customary international law, relevant for each spacefaring state. Registration is divided into a national and an international level. The State Party establishes a national registry for its space objects, and those registrations have to be communicated via diplomatic channel to the UN Register of space objects. This UN Register is handled by the UN Office for Outer Space Affairs (UNOOSA) and is an open source of information for space objects worldwide. Registration is linked to the so-called launching state of the relevant space object. There might be more than one launching state for the specific launch event, but only one state actor can register a specific space object. The state of registry gains "jurisdiction and control" over the space object and therefore no double registration is permissible. Based on the established UN Space Law, registration practice was subject to some adaptions due to technical developments and legal challenges. After the privatization of the major international satellite organizations, a number of non-registrations had to be faced. The state actors reacted with the UN Registration Practice Resolution of 2007 as elaborated in the Legal Subcommittee of UNCOPUOS, the Committee for the Peaceful Use of Outer Space. In this context an UNOOSA Registration Information Submission Form had been developed. Today the complexity of launch activities and the concepts of mega-constellations lead to new challenges to the registration system. The Registration Practice Resolution already recommends that in cases of joint launches, each space object should be registered separately. Registration of space objects is a legal instrument in the context of state responsibility; it is not an instrument of traffic management. The orbit information of the registration system is indicative for identification purposes but not real-time positioning information. Such traffic management information follows different rules.

Active black holes: Relevant plasma structures, regimes and processes involving all phase space

NASA Astrophysics Data System (ADS)

Coppi, Bruno

2011-03-01

The presented theory is motivated by the growing body of experimental information on the characteristics, connected with relevant spectral, time, and space resolutions, of the radiation emission from objects considered as rotating black holes. In the immediate surroundings of these objects, three plasma regions are identified: an innermost Buffer Region, an intermediate Three-regime Region, and a Structured Peripheral Region. In the last region, a Composite Disk Structure made of a sequence of plasma rings corresponding to the formation of closed magnetic surfaces is considered to be present and to allow intermittent accretion flows along the relevant separatrices. The nonlinear ``Master Equation'' describing composite disk structures is derived and solved in appropriate asymptotic limits. A ring configuration, depending on the state of the plasma at the microscopic level: (i) can be excluded from forming given the strongly nonthermal nature of the electron distribution (in momentum space) within the Three-regime Region allowing the onset of a spiral structure; the observed High Frequency Quasi Periodic Oscillations are associated with these tridimensional structures; (ii) may be allowed to propagate to the outer edge of the Buffer Region where successive rings carrying currents in opposite directions are ejected vertically (in opposite directions) and originate the observed jets; or (iii) penetrates in the Three-regime Region and is dissipated before reaching the outer edge of the Buffer Region. The absence of a coherent composite disk structure guiding accretion in the presence of a significant magnetic field background is suggested to characterize quiescent black holes.

Impact of contour on aesthetic judgments and approach-avoidance decisions in architecture

PubMed Central

Vartanian, Oshin; Navarrete, Gorka; Chatterjee, Anjan; Fich, Lars Brorson; Leder, Helmut; Modroño, Cristián; Nadal, Marcos; Rostrup, Nicolai; Skov, Martin

2013-01-01

On average, we urban dwellers spend about 90% of our time indoors, and share the intuition that the physical features of the places we live and work in influence how we feel and act. However, there is surprisingly little research on how architecture impacts behavior, much less on how it influences brain function. To begin closing this gap, we conducted a functional magnetic resonance imaging study to examine how systematic variation in contour impacts aesthetic judgments and approach-avoidance decisions, outcome measures of interest to both architects and users of spaces alike. As predicted, participants were more likely to judge spaces as beautiful if they were curvilinear than rectilinear. Neuroanatomically, when contemplating beauty, curvilinear contour activated the anterior cingulate cortex exclusively, a region strongly responsive to the reward properties and emotional salience of objects. Complementing this finding, pleasantness—the valence dimension of the affect circumplex—accounted for nearly 60% of the variance in beauty ratings. Furthermore, activation in a distributed brain network known to underlie the aesthetic evaluation of different types of visual stimuli covaried with beauty ratings. In contrast, contour did not affect approach-avoidance decisions, although curvilinear spaces activated the visual cortex. The results suggest that the well-established effect of contour on aesthetic preference can be extended to architecture. Furthermore, the combination of our behavioral and neural evidence underscores the role of emotion in our preference for curvilinear objects in this domain. PMID:23754408

14 CFR 1203.201 - Information security objectives.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Information security objectives. 1203.201 Section 1203.201 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION INFORMATION SECURITY PROGRAM NASA Information Security Program § 1203.201 Information security objectives. The objectives of...

14 CFR 1203.201 - Information security objectives.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Information security objectives. 1203.201 Section 1203.201 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION INFORMATION SECURITY PROGRAM NASA Information Security Program § 1203.201 Information security objectives. The objectives of...

ISODEX: An entry point for developing countries into space activities

NASA Astrophysics Data System (ADS)

Skinner, Mark Andrew

2015-08-01

Several threads current in the community of international space actors have led to calls at UN COPUOS Scientific & Technical Sub-Committee meetings for enhancing the scientific information available on man-made space objects, whilst fostering international space object data sharing. Growing awareness of the problems of space debris proliferation and space traffic management, especially amongst developing countries and non-traditional space faring nations, have fueled their desires to become involved in the areas of space object tracking, utilizing relatively modest astronomical instrumentation. Additionally, several commercial satellite operators, members of the Satellite Data Association, have called for augmentation of the information available from existing catalogs. This confluence of factors has led to an international discussion, at the UN and elsewhere, of the possibility of creating a clearing-house for parties willing to share data on space objects, with a working title of the “International Space Object Data Exchange” (ISODEX). We discuss the ideas behind this concept, how it might be implemented, and it might enhance the public’s knowledge of space activities, as well as providing an entry point into space for developing countries.

Direct imaging search for the "missing link" in giant planet formation

NASA Astrophysics Data System (ADS)

Ngo, Henry; Mawet, Dimitri; Ruane, Garreth; Xuan, Wenhao; Bowler, Brendan; Cook, Therese; Zawol, Zoe

2018-01-01

While transit and radial velocity detection techniques have probed giant planet populations at close separations (within a few au), current direct imaging surveys are finding giant planets at separations of 10s-100s au. Furthermore, these directly imaged planets are very massive, including some with masses above the deuterium burning limit. It is not certain whether these objects represent the high mass end of planet formation scenarios or the low mass end of star formation. We present a direct imaging survey to search for the "missing link" population between the close-in RV and transiting giant planets and the extremely distant directly imaged giant planets (i.e. giant planets between 5-10 au). Finding and characterizing this population allows for comparisons with the formation models of closer-in planets and connects directly imaged planets with closer-in planets in semi-major axis phase space. In addition, microlensing surveys have suggested a large reservoir of giant planets exist in this region. To find these "missing link" giant planets, our survey searches for giant planets around M-stars. The ubiquity of M-stars provide a large number of nearby targets and their L-band contrast with planets allow for sensitivities to smaller planet masses than surveys conducted at shorter wavelengths. Along with careful target selection, we use Keck's L-band vector vortex coronagraph to enable sensitivities of a few Jupiter masses as close as 4 au to their host stars. We present our completed 2-year survey targeting 200 young (10-150 Myr), nearby M-stars and our ongoing work to follow-up over 40 candidate objects.

Research of cartographer laser SLAM algorithm

NASA Astrophysics Data System (ADS)

Xu, Bo; Liu, Zhengjun; Fu, Yiran; Zhang, Changsai

2017-11-01

As the indoor is a relatively closed and small space, total station, GPS, close-range photogrammetry technology is difficult to achieve fast and accurate indoor three-dimensional space reconstruction task. LIDAR SLAM technology does not rely on the external environment a priori knowledge, only use their own portable lidar, IMU, odometer and other sensors to establish an independent environment map, a good solution to this problem. This paper analyzes the Google Cartographer laser SLAM algorithm from the point cloud matching and closed loop detection. Finally, the algorithm is presented in the 3D visualization tool RViz from the data acquisition and processing to create the environment map, complete the SLAM technology and realize the process of indoor threedimensional space reconstruction

Ecohydrological controls on soil moisture and hydraulic conductivity within a pinyon‐juniper woodland

USGS Publications Warehouse

Lebron, I.; Madsen, M.D.; Chandler, D.G.; Robinson, D.A.; Wendroth, O.; Belnap, J.

2007-01-01

The impact of pinyon‐juniper woodland encroachment on rangeland ecosystems is often associated with a reduction of streamflow and recharge and an increase in soil erosion. The objective of this study is to investigate vegetational control on seasonal soil hydrologic properties along a 15‐m transect in pinyon‐juniper woodland with biocrust. We demonstrate that the juniper tree controls soil water content (SWC) patterns directly under the canopy via interception, and beyond the canopy via shading in a preferred orientation, opposite to the prevailing wind direction. The juniper also controls the SWC and unsaturated hydraulic conductivity measured close to water saturation (K(h)) under the canopy by the creation of soil water repellency due to needle drop. We use this information to refine the hydrologic functional unit (HFU) concept into three interacting hydrologic units: canopy patches, intercanopy patches, and a transitional unit formed by intercanopy patches in the rain shadow of the juniper tree. Spatial autoregressive state‐space models show the close relationship between K(h) close to soil water saturation and SWC at medium and low levels, integrating a number of influences on hydraulic conductivity.

IoSiS: a radar system for imaging of satellites in space

NASA Astrophysics Data System (ADS)

Jirousek, M.; Anger, S.; Dill, S.; Schreiber, E.; Peichl, M.

2017-05-01

Space debris nowadays is one of the main threats for satellite systems especially in low earth orbit (LEO). More than 700,000 debris objects with potential to destroy or damage a satellite are estimated. The effects of an impact often are not identifiable directly from ground. High-resolution radar images are helpful in analyzing a possible damage. Therefor DLR is currently developing a radar system called IoSiS (Imaging of Satellites in Space), being based on an existing steering antenna structure and our multi-purpose high-performance radar system GigaRad for experimental investigations. GigaRad is a multi-channel system operating at X band and using a bandwidth of up to 4.4 GHz in the IoSiS configuration, providing fully separated transmit (TX) and receive (RX) channels, and separated antennas. For the observation of small satellites or space debris a highpower traveling-wave-tube amplifier (TWTA) is mounted close to the TX antenna feed. For the experimental phase IoSiS uses a 9 m TX and a 1 m RX antenna mounted on a common steerable positioner. High-resolution radar images are obtained by using Inverse Synthetic Aperture Radar (ISAR) techniques. The guided tracking of known objects during overpass allows here wide azimuth observation angles. Thus high azimuth resolution comparable to the range resolution can be achieved. This paper outlines technical main characteristics of the IoSiS radar system including the basic setup of the antenna, the radar instrument with the RF error correction, and the measurement strategy. Also a short description about a simulation tool for the whole instrument and expected images is shown.

Closeup view if the starboard side of the crew compartment ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Close-up view if the starboard side of the crew compartment mid-deck of the Orbiter Discovery. This is a close up view of the galley for meal preparations. In the center right of the image is stowage lockers that are designated to store meals for the mission. This photograph was taken at Kennedy Space Center. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

Close up view under the Orbiter Discovery in the Vehicle ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Close up view under the Orbiter Discovery in the Vehicle Assembly Building at NASA's Kennedy Space Center. The view is under the port wing looking forward toward the main fuselage showing a detail of the landing gear and landing gear door. This view also shows the patterns of worn and replaced High-temperature Reusable Surface Insulation tiles. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

Closeup view of the Solid Rocket Booster Frustum and Nose ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Close-up view of the Solid Rocket Booster Frustum and Nose Cap assembly undergoing preparations and close-out procedures in the Solid Rocket Booster Assembly and Refurbishment Facility at Kennedy Space Center. The Nose Cap contains the Pilot and Drogue Chutes and the Frustum contains the three Main Parachutes, Altitude Switches and forward booster Separation Motors. - Space Transportation System, Solid Rocket Boosters, Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

Stability of Multi-Planet Systems Orbiting in the Alpha Centauri AB System

NASA Astrophysics Data System (ADS)

Lissauer, Jack

2018-04-01

We evaluate how closely-spaced planetary orbits in multiple planet systems can be and still survive for billion-year timescales within the alpha Centauri AB system. Although individual planets on nearly circular, coplanar orbits can survive throughout the habitable zones of both stars, perturbations from the companion star imply that the spacing of such planets in multi-planet systems must be significantly larger than the spacing of similar systems orbiting single stars in order to be long-lived. Because the binary companion induces a forced eccentricity upon circumstellar planets, stable orbits with small initial eccentricities aligned with the binary orbit are possible to slightly larger initial semimajor axes than are initially circular orbits. Initial eccentricities close to the appropriate forced eccentricity can have a much larger affect on how closely planetary orbits can be spaced, on how many planets may remain in the habitable zones, although the required spacing remains significantly higher than for planets orbiting single stars.

Trajectory-probed instability and statistics of desynchronization events in coupled chaotic systems

NASA Astrophysics Data System (ADS)

de Oliveira, Gilson F.; Chevrollier, Martine; Passerat de Silans, Thierry; Oriá, Marcos; de Souza Cavalcante, Hugo L. D.

2015-11-01

Complex systems, such as financial markets, earthquakes, and neurological networks, exhibit extreme events whose mechanisms of formation are not still completely understood. These mechanisms may be identified and better studied in simpler systems with dynamical features similar to the ones encountered in the complex system of interest. For instance, sudden and brief departures from the synchronized state observed in coupled chaotic systems were shown to display non-normal statistical distributions similar to events observed in the complex systems cited above. The current hypothesis accepted is that these desynchronization events are influenced by the presence of unstable object(s) in the phase space of the system. Here, we present further evidence that the occurrence of large events is triggered by the visitation of the system's phase-space trajectory to the vicinity of these unstable objects. In the system studied here, this visitation is controlled by a single parameter, and we exploit this feature to observe the effect of the visitation rate in the overall instability of the synchronized state. We find that the probability of escapes from the synchronized state and the size of those desynchronization events are enhanced in attractors whose shapes permit the chaotic trajectories to approach the region of strong instability. This result shows that the occurrence of large events requires not only a large local instability to amplify noise, or to amplify the effect of parameter mismatch between the coupled subsystems, but also that the trajectories of the system wander close to this local instability.

Close It, Sell It, or Lease It: What to Do with That Old School.

ERIC Educational Resources Information Center

Schomp, Katherine W.

The Denver (Colorado) Board of Education has taken a number of steps to avoid closing schools. Among these are refiguring school capacities; providing full-time space for programs that do not always function full-time; providing additional private space for related services (psychological, social work, and nursing); expanding instructional…

Don't Panic! Closed String Tachyons in ALE Spacetimes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silverstein, Eva M

2001-08-20

We consider closed string tachyons localized at the fixed points of noncompact nonsupersymmetric orbifolds. We argue that tachyon condensation drives these orbifolds to flat space or supersymmetric ALE spaces. The decay proceeds via an expanding shell of dilaton gradients and curvature which interpolates between two regions of distinct angular geometry. The string coupling remains weak throughout. For small tachyon VEVs, evidence comes from quiver theories on D-branes probes, in which deformations by twisted couplings smoothly connect non-supersymmetric orbifolds to supersymmetric orbifolds of reduced order. For large tachyon VEVs, evidence comes from worldsheet RG flow and spacetime gravity. For C{sup 2}/Z{submore » n}, we exhibit infinite sequences of transitions producing SUSY ALE spaces via twisted closed string condensation from non-supersymmetric ALE spaces. In a T-dual description this provides a mechanism for creating NS5-branes via closed string tachyon condensation similar to the creation of D-branes via open string tachyon condensation. We also apply our results to recent duality conjectures involving fluxbranes and the type 0 string.« less

Space Station Freedom Utilization Conference

NASA Technical Reports Server (NTRS)

1992-01-01

The topics addressed in Space Station Freedom Utilization Conference are: (1) space station freedom overview and research capabilities; (2) space station freedom research plans and opportunities; (3) life sciences research on space station freedom; (4) technology research on space station freedom; (5) microgravity research and biotechnology on space station freedom; and (6) closing plenary.

Space Solar Power Exploratory Research and Technology (SERT) Technical Interchange Meeting 2 (SERT TIM 2)

NASA Technical Reports Server (NTRS)

Howell, Joe; Sanders, Clark W.

2000-01-01

The University of Alabama in Huntsville's (UAH) Propulsion Research Center hosted the Space Solar Power Exploratory Research & Technology (SERT) Technical Interchange Meeting TIM) 2 in Huntsville, Alabama December 7-10. 1999 with 126 people in attendance. The SERT program includes both competitively procured activities. which are being implemented through a portfolio of focused R&D investments--with the maximum leveraging of existing resources inside and outside NASA. and guided by these system studies. Axel Roth. Director of the Flight Projects Directorate NASA MSFC, welcomed the SERT TIM 2 participants and challenged them to develop the necessary technologies and demonstrations that will lead to Space Solar Power (SSP) International implementation. Joe Howell, NASA MSFC, reiterated the SERT TIM 2 objectives: 1) Refining and modeling systems approaches for the utilization of SSP concepts and technologies, ranging, from the near-term e.g. for space science, exploration and commercial space applications to the far-term (e. g. SSP for terrestrial markets), including systems concepts, technology, infrastructure (i.g., transportation), and economics. 2) Conducting technology research, development and demonstration activities to produce "proof- of-concept" validation of critical SSP elements for both the nearer and farther-term applications. 3) Initiating partnerships Nationality and Internationally that could be expanded, as appropriate, to pursue later SSP technology and applications (e.g., space science. colonization, etc.). Day one began with the NASA Centers presenting their SERT activities summary since SERT TIM 1 and wound up with a presentation by Masahiro Mori, NASDA titled "NASDA In-house Study for SSP". Demonstration for the Near-Term. Day two began with the SERT Systems Studies and Analysis reports resulting from NRA 8-23 followed by presentations of SERT Technology Demonstrations reports resulting from NRA 8-23. Day two closed with John Mankins presentation on "Technology Roadmapping" and the delivery of the charge to the Work Breakout Sessions. Day three began with the eleven Work Breakout Session which was the major function of this TIM 2 and day three ended with reports by the Chairs of the eleven Work Breakdown Sessions. Day four began with the six Integrated Product Team OPT) meetings and ended with closing plenary panel sessions.

Awareness-based game-theoretic space resource management

NASA Astrophysics Data System (ADS)

Chen, Genshe; Chen, Huimin; Pham, Khanh; Blasch, Erik; Cruz, Jose B., Jr.

2009-05-01

Over recent decades, the space environment becomes more complex with a significant increase in space debris and a greater density of spacecraft, which poses great difficulties to efficient and reliable space operations. In this paper we present a Hierarchical Sensor Management (HSM) method to space operations by (a) accommodating awareness modeling and updating and (b) collaborative search and tracking space objects. The basic approach is described as follows. Firstly, partition the relevant region of interest into district cells. Second, initialize and model the dynamics of each cell with awareness and object covariance according to prior information. Secondly, explicitly assign sensing resources to objects with user specified requirements. Note that when an object has intelligent response to the sensing event, the sensor assigned to observe an intelligent object may switch from time-to-time between a strong, active signal mode and a passive mode to maximize the total amount of information to be obtained over a multi-step time horizon and avoid risks. Thirdly, if all explicitly specified requirements are satisfied and there are still more sensing resources available, we assign the additional sensing resources to objects without explicitly specified requirements via an information based approach. Finally, sensor scheduling is applied to each sensor-object or sensor-cell pair according to the object type. We demonstrate our method with realistic space resources management scenario using NASA's General Mission Analysis Tool (GMAT) for space object search and track with multiple space borne observers.

Automatic 3D power line reconstruction of multi-angular imaging power line inspection system

NASA Astrophysics Data System (ADS)

Zhang, Wuming; Yan, Guangjian; Wang, Ning; Li, Qiaozhi; Zhao, Wei

2007-06-01

We develop a multi-angular imaging power line inspection system. Its main objective is to monitor the relative distance between high voltage power line and around objects, and alert if the warning threshold is exceeded. Our multi-angular imaging power line inspection system generates DSM of the power line passage, which comprises ground surface and ground objects, for example trees and houses, etc. For the purpose of revealing the dangerous regions, where ground objects are too close to the power line, 3D power line information should be extracted at the same time. In order to improve the automation level of extraction, reduce labour costs and human errors, an automatic 3D power line reconstruction method is proposed and implemented. It can be achieved by using epipolar constraint and prior knowledge of pole tower's height. After that, the proper 3D power line information can be obtained by space intersection using found homologous projections. The flight experiment result shows that the proposed method can successfully reconstruct 3D power line, and the measurement accuracy of the relative distance satisfies the user requirement of 0.5m.

Sonar beam dynamics in leaf-nosed bats

PubMed Central

Linnenschmidt, Meike; Wiegrebe, Lutz

2016-01-01

Ultrasonic emissions of bats are directional and delimit the echo-acoustic space. Directionality is quantified by the aperture of the sonar beam. Recent work has shown that bats often widen their sonar beam when approaching movable prey or sharpen their sonar beam when navigating through cluttered habitats. Here we report how nose-emitting bats, Phyllostomus discolor, adjust their sonar beam to object distance. First, we show that the height and width of the bats sonar beam, as imprinted on a parabolic 45 channel microphone array, varies even within each animal and this variation is unrelated to changes in call level or spectral content. Second, we show that these animals are able to systematically decrease height and width of their sonar beam while focusing on the approaching object. Thus it appears that sonar beam sharpening is a further, facultative means of reducing search volume, likely to be employed by stationary animals when the object position is close and unambiguous. As only half of our individuals sharpened their beam onto the approaching object we suggest that this strategy is facultative, under voluntary control, and that beam formation is likely mediated by muscular control of the acoustic aperture of the bats’ nose leaf. PMID:27384865

Sonar beam dynamics in leaf-nosed bats.

PubMed

Linnenschmidt, Meike; Wiegrebe, Lutz

2016-07-07

Ultrasonic emissions of bats are directional and delimit the echo-acoustic space. Directionality is quantified by the aperture of the sonar beam. Recent work has shown that bats often widen their sonar beam when approaching movable prey or sharpen their sonar beam when navigating through cluttered habitats. Here we report how nose-emitting bats, Phyllostomus discolor, adjust their sonar beam to object distance. First, we show that the height and width of the bats sonar beam, as imprinted on a parabolic 45 channel microphone array, varies even within each animal and this variation is unrelated to changes in call level or spectral content. Second, we show that these animals are able to systematically decrease height and width of their sonar beam while focusing on the approaching object. Thus it appears that sonar beam sharpening is a further, facultative means of reducing search volume, likely to be employed by stationary animals when the object position is close and unambiguous. As only half of our individuals sharpened their beam onto the approaching object we suggest that this strategy is facultative, under voluntary control, and that beam formation is likely mediated by muscular control of the acoustic aperture of the bats' nose leaf.

The binary Kuiper-belt object 1998 WW31.

PubMed

Veillet, Christian; Parker, Joel Wm; Griffin, Ian; Marsden, Brian; Doressoundiram, Alain; Buie, Marc; Tholen, David J; Connelley, Michael; Holman, Matthew J

2002-04-18

The recent discovery of a binary asteroid during a spacecraft fly-by generated keen interest, because the orbital parameters of binaries can provide measures of the masses, and mutual eclipses could allow us to determine individual sizes and bulk densities. Several binary near-Earth, main-belt and Trojan asteroids have subsequently been discovered. The Kuiper belt-the region of space extending from Neptune (at 30 astronomical units) to well over 100 AU and believed to be the source of new short-period comets-has become a fascinating new window onto the formation of our Solar System since the first member object, not counting Pluto, was discovered in 1992 (ref. 13). Here we report that the Kuiper-belt object 1998 WW31 is binary with a highly eccentric orbit (eccentricity e approximately 0.8) and a long period (about 570 days), very different from the Pluto/Charon system, which was hitherto the only previously known binary in the Kuiper belt. Assuming a density in the range of 1 to 2 g cm-3, the albedo of the binary components is between 0.05 and 0.08, close to the value of 0.04 generally assumed for Kuiper-belt objects.

Active vibration absorber for CSI evolutionary model: Design and experimental results

NASA Technical Reports Server (NTRS)

Bruner, Anne M.; Belvin, W. Keith; Horta, Lucas G.; Juang, Jer-Nan

1991-01-01

The development of control of large flexible structures technology must include practical demonstration to aid in the understanding and characterization of controlled structures in space. To support this effort, a testbed facility was developed to study practical implementation of new control technologies under realistic conditions. The design is discussed of a second order, acceleration feedback controller which acts as an active vibration absorber. This controller provides guaranteed stability margins for collocated sensor/actuator pairs in the absence of sensor/actuator dynamics and computational time delay. The primary performance objective considered is damping augmentation of the first nine structural modes. Comparison of experimental and predicted closed loop damping is presented, including test and simulation time histories for open and closed loop cases. Although the simulation and test results are not in full agreement, robustness of this design under model uncertainty is demonstrated. The basic advantage of this second order controller design is that the stability of the controller is model independent.

Design development of graphite primary structures enables SSTO success

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biagiotti, V.A.; Yahiro, J.S.; Suh, D.E.

1997-01-01

This paper describes the development of a graphite composite wing and a graphite composite intertank primary structure for application toward Single-Stage to Orbit space vehicles such as those under development in NASA{close_quote}s X-33/Reusable Launch Vehicle (RLV) Program. The trade study and designs are based on a Rockwell vertical take-off and horizontal landing (VTHL) wing-body RLV vehicle. Northrop Grumman{close_quote}s approach using a building block development technique is described. Composite Graphite/Bismaleimide (Gr/BMI) material characterization test results are presented. Unique intertank and wing composite subcomponent test article designs are described and test results to date are presented. Wing and intertank Full Scale Sectionmore » Test Article (FSTA) objectives and designs are outlined. Trade studies, supporting building block testing, and FSTA demonstrations combine to develop graphite primary structure composite technology that enables developing X-33/RLV design programs to meet critical SSTO structural weight and operations performance criteria. {copyright} {ital 1997 American Institute of Physics.}« less

A Concept for Providing Warning of Chelyabinsk-like Meteors, including those approaching from the Sun

NASA Astrophysics Data System (ADS)

Dunham, D. W.; Reitsema, H.; Lu, E.; Arentz, R.; Linfield, R.; Chapman, C. R.; Farquhar, R. W.; Furfaro, R.; Eismont, N. A.; Ledkov, A.; Chumachenko, E.

2013-12-01

The detonation of a 20m-asteroid above Chelyabinsk, Russia on 2013 February 15 shows that even small asteroids can cause extensive damage. Earth-based telescopes have found smaller harmless objects, such as 2008 TC3, discovered 20h before it exploded over northern Sudan . 2008 TC3 remains the only asteroid discovered before it hit Earth because it approached Earth from the night side, where it was observed by large telescopes searching for near-Earth objects. The larger object that exploded over Chelyabinsk approached Earth from the day side, from too close to the Sun to be detected from Earth. A sizeable telescope in an orbit about the Sun-Earth L1 (SE-L1) libration point 1.5 million km from Earth towards the Sun (about 4 times the distance to the Moon) could find objects like the 'Chelyabinsk' asteroid approaching approximately from the line of sight to the Sun about a day before Earth closest approach; this would find the approximately 35% of asteroids that approach Earth from a direction too close to the Sun to be observed, or likely to be missed, from the ground. Our concept would give at least several hours, and often a day or more, to take protective measures, rather than the approximately two-minute interval between the flash and shock wave arrival that occurred in Chelyabinsk. An important reason for providing warning of these events, even smaller harmless ones that explode high in the atmosphere with the force of an atomic bomb, is to prevent mistaking such an event for a nuclear attack that could trigger a devastating nuclear war. This concept could also discover many small asteroids that would not impact Earth; some of them would likely be suitable for retrieval to move to a lunar orbit for study by astronauts in the next decade. A concept using a space telescope similar to that needed by our concept is already conceived by the B612 Foundation, whose planned Sentinel Space Telescope could find nearly all 140m and larger near-Earth objects (NEO's), including those in orbits mostly inside the Earth's orbit that are hard to find with Earth-based telescopes, from a Venus-like orbit. Few modifications would be needed to the 50cm aperture passively-cooled infrared-observing Sentinel Space Telescope to operate in a SE-L1 orbit, 0.01 AU from Earth towards the Sun, to find most asteroids larger than about 5 meters that approach the Earth from the solar direction. Many objects in the 25-50m range will not be found by current NEO surveys, while they would nearly always be seen by this possible mission. A dense metallic NEO as small as 5m across can rain destruction over an area of 1 or 2 square kilometers, as the Sikhote-Alin meteor showed in 1947 Other concepts are either ineffective at providing warning of asteroids approaching from the Sun, or are more expensive, involving three or more spacecraft. We should give better warning for future 'Bolts out of the blue'.

Control of Space-Based Electron Beam Free Form Fabrication

NASA Technical Reports Server (NTRS)

Seifzer. W. J.; Taminger, K. M.

2007-01-01

Engineering a closed-loop control system for an electron beam welder for space-based additive manufacturing is challenging. For earth and space based applications, components must work in a vacuum and optical components become occluded with metal vapor deposition. For extraterrestrial applications added components increase launch weight, increase complexity, and increase space flight certification efforts. Here we present a software tool that closely couples path planning and E-beam parameter controls into the build process to increase flexibility. In an environment where data collection hinders real-time control, another approach is considered that will still yield a high quality build.

Emergence of topological semimetals in gap closing in semiconductors without inversion symmetry.

PubMed

Murakami, Shuichi; Hirayama, Motoaki; Okugawa, Ryo; Miyake, Takashi

2017-05-01

A band gap for electronic states in crystals governs various properties of solids, such as transport, optical, and magnetic properties. Its estimation and control have been an important issue in solid-state physics. The band gap can be controlled externally by various parameters, such as pressure, atomic compositions, and external field. Sometimes, the gap even collapses by tuning some parameter. In the field of topological insulators, this closing of the gap at a time-reversal invariant momentum indicates a band inversion, that is, it leads to a topological phase transition from a normal insulator to a topological insulator. We show, through an exhaustive study on possible space groups, that the gap closing in inversion-asymmetric crystals is universal, in the sense that the gap closing always leads either to a Weyl semimetal or to a nodal-line semimetal. We consider three-dimensional spinful systems with time-reversal symmetry. The space group of the system and the wave vector at the gap closing uniquely determine which possibility occurs and where the gap-closing points or lines lie in the wave vector space after the closing of the gap. In particular, we show that an insulator-to-insulator transition never happens, which is in sharp contrast to inversion-symmetric systems.

Are object- and space-based attentional biases both important to free-viewing perceptual asymmetries?

PubMed

Nicholls, Michael E R; Hughes, Georgina; Mattingley, Jason B; Bradshaw, John L

2004-02-01

In contrast to unilateral neglect patients, who overattend to the right hemispace, normal participants attend more to the left: a phenomenon known as pseudoneglect. Two experiments examined whether pseudoneglect results from object- or space-based attentional biases. Normal participants ( n=38, 22) made luminance judgments for two left/right mirror-reversed luminance gradients (greyscales task). The relative lateral position of the greyscales stimuli was manipulated so that object- and space-based coordinates were congruent or incongruent. A baseline condition was also included. A leftward bias, found for the baseline condition, was annulled in the incongruent condition, demonstrating an opposition of object- and space-based biases. The leftward bias was reduced in the congruent condition where object- and space-based biases were expected to be additive. This effect was attributed to extraneous factors, which were avoided in the second experiment by presenting the greyscales stimuli sequentially. Once again, no bias was observed in the incongruent condition where object- and space-based biases were opposed. The leftward bias in the congruent condition was the same as the baseline. The results can be explained by a combination of space- and object-based biases or by space-based biases alone and are discussed with reference to a variety of models, which describe the distribution of attention across space.

Close-up of Shuttle Thermal Tiles in Space

NASA Technical Reports Server (NTRS)

2005-01-01

Launched on July 26 2005, from the Kennedy Space Center in Florida, STS-114 was classified as Logistics Flight 1. Among the Station-related activities of the mission were the delivery of new supplies and the replacement of one of the orbital outpost's Control Moment Gyroscopes (CMGs). STS-114 also carried the Raffaello Multi-Purpose Logistics Module and the External Stowage Platform-2. A major focus of the mission was the testing and evaluation of new Space Shuttle flight safety, which included new inspection and repair techniques. Upon its approach to the International Space Station (ISS), the Space Shuttle Discovery underwent a photography session in order to assess any damages that may have occurred during its launch and/or journey through Space. The mission's third and final Extra Vehicular Activity (EVA) included taking a close-up look and the repair of the damaged heat shield. Gap fillers were removed from between the orbiter's heat-shielding tiles located on the craft's underbelly. Never before had any repairs been done to an orbiter while still in space. This close up of the thermal tiles was taken by astronaut Stephen K. Robinson, STS-114 mission specialist (out of frame). Astronaut Soichi Noguchi, STS-114 mission specialist representing the Japan Aerospace Exploration (JAXA), can be seen in the background perched on a Space Station truss.

Effects of logging on roadless space in intact forest landscapes of the Congo Basin.

PubMed

Kleinschroth, Fritz; Healey, John R; Gourlet-Fleury, Sylvie; Mortier, Frédéric; Stoica, Radu S

2017-04-01

Forest degradation in the tropics is often associated with roads built for selective logging. The protection of intact forest landscapes (IFL) that are not accessible by roads is high on the biodiversity conservation agenda and a challenge for logging concessions certified by the Forest Stewardship Council (FSC). A frequently advocated conservation objective is to maximize the retention of roadless space, a concept that is based on distance to the nearest road from any point. We developed a novel use of the empty-space function - a general statistical tool based on stochastic geometry and random sets theory - to calculate roadless space in a part of the Congo Basin where road networks have been expanding rapidly. We compared the temporal development of roadless space in certified and uncertified logging concessions inside and outside areas declared IFL in 2000. Inside IFLs, road-network expansion led to a decrease in roadless space by more than half from 1999 to 2007. After 2007, loss leveled out in most areas to close to 0 due to an equilibrium between newly built roads and abandoned roads that became revegetated. However, concessions in IFL certified by FSC since around 2007 continuously lost roadless space and reached a level comparable to all other concessions. Only national parks remained mostly roadless. We recommend that forest-management policies make the preservation of large connected forest areas a top priority by effectively monitoring - and limiting - the occupation of space by roads that are permanently accessible. © 2016 The Authors. Conservation Biology published by Wiley Periodicals, Inc. on behalf of Society for Conservation Biology.

Elements of ESA's policy on space and security

NASA Astrophysics Data System (ADS)

Giannopapa, Christina; Adriaensen, Maarten; Antoni, Ntorina; Schrogl, Kai-Uwe

2018-06-01

In the past decade Europe has been facing rising security threats, ranging from climate change, migrations, nearby conflicts and crises, to terrorism. The demand to tackle these critical challenges is increasing in Member States. Space is already contributing, and could further contribute with already existing systems and future ones. The increasing need for security in Europe and for safety and security of Europe's space activities has led to a growing number of activities in ESA in various domains. It has also driven new and strengthened partnerships with security stakeholders in Europe. At the European level, ESA is collaborating closely with the main European institutions dealing with space security. In addition, as an organisation ESA has evolved to conduct security-related projects and programmes and to address the threats to its own activities, thereby securing the investments of the Member States. Over the past years the Agency has set up a comprehensive regulatory framework in order to be able to cope with security related requirements. Over the past years, ESA has increased its exchanges with its Member States. The paper presents main elements of the ESA's policy on space and security. It introduces the current European context for space and security, the European goals in this domain and the specific objectives to which the Agency intends to contribute. Space and security in the ESA context is set out under two components: a) security from space and b) security in space, including the security of ESA's own activities (corporate security and the security of ESA's space missions). Subsequently, ESA's activities are elaborated around these two pillars, composed of different activities conducted in the most appropriate frameworks and in coordination with the relevant stakeholders and shareholders.

Analysis of technical spin-off effects of space-related R&D by means of patent indicators

NASA Astrophysics Data System (ADS)

Schmoch, U.; Kirsch, N.; Ley, W.; Plescher, E.; Jung, K. O.

In view of increasing European activity in the field of manned space travel, intense discussion has arisen on the significance of associated spin-off effects. Alongside this predominantly political debate, however, there is also a purely pragmatic interest in transferring wherever possible the successful results from space research to other branches of industry, in order to achieve optimum exploitation of all the resources available. Until now, spin-offs from space technology have been analyzed by means of interviews conducted in the firms involved, a process harbouring a whole series of uncertainty factors. Potential spin-off fields are frequently ignored, and alleged transfers from space research often in reality stem from other sources. This survey develops an objective method of describing technology transfer based on patent indicators. The first step was to establish on line a total of some 3000 space patents filed since 1975 with destination to the European and American markets. This record is sufficient to permit an analysis of the R&D activities undertaken by the leading industrial nations in the space sector. With further assistance provided by the method of analyzing patent citations, however, it is then possible to discover spin-off effects in areas outside space technology, which are nevertheless closely related in technical terms to the basic space patents with which they are associated. In this way, it is possible to define areas which are particularly suited to adopt space technologies in earthbound applications. This method of analyzing citations, which in principle is familiar for describing technology transfer within any one technical field, has thus been successfully employed for the first time for analyzing spin-offs.

Assessment of Technologies for the Space Shuttle External Tank Thermal Protection System and Recommendations for Technology Improvement. Part 1; Materials Characterization and Analysis

NASA Technical Reports Server (NTRS)

Weiser, Erik S.; SaintClair, Terry L.; Nemeth, Michael P.

2004-01-01

The use of foam insulation on the External Tank (ET) was necessitated by the potentially hazardous build up of ice on the vehicle prior to and during launch. This use of foam was initiated on the Saturn V rocket, which, like the Space Shuttle, used cryogenic fuel. Two major types of foam have been used on the ET. The first type is NCFI 24-124, an acreage material that is automatically sprayed on in a controlled environment. It replaced CPR 488 in 1998 and has been used since that time. The other major foams, BX-250 or BX-265, are handsprayed foams that are used to close out regions where the various sections of the ET are attached. The objectives of the present report are to study the chemistries of the various foam materials and to determine how physical and mechanical anomalies might occur during the spray and curing process. To accomplish these objectives, the report is organized as follows. First, the chemistries of the raw materials will be discussed. This will be followed by a discussion of how chemistry relates to void formation. Finally, a TGA-MS will be used to help understand the various foams and how they degrade with the evolution of chemical by-products.

Exploring the feasibility of focusing CW light through a scattering medium into closely spaced twin peaks via numerical solutions of Maxwell’s equations

NASA Astrophysics Data System (ADS)

Tseng, Snow H.; Chang, Shih-Hui

2018-04-01

Here we present a numerical simulation to analyze the effect of scattering on focusing light into closely-spaced twin peaks. The pseudospectral time-domain (PSTD) is implemented to model continuous-wave (CW) light propagation through a scattering medium. Simulations show that CW light can propagate through a scattering medium and focus into closely-spaced twin peaks. CW light of various wavelengths focusing into twin peaks with sub-diffraction spacing is simulated. In advance, light propagation through scattering media of various number densities is simulated to decipher the dependence of CW light focusing phenomenon on the scattering medium. The reported simulations demonstrate the feasibility of focusing CW light into twin peaks with sub-diffraction dimensions. More importantly, based upon numerical solutions of Maxwell’s equations, research findings show that the sub-diffraction focusing phenomenon can be achieved with scarce or densely-packed scattering media.

High Contrast Programmable Field Masks for JWST NIRSpec

NASA Technical Reports Server (NTRS)

Kutyrev, Alexander S.

2008-01-01

Microshutter arrays are one of the novel technologies developed for the James Webb Space Telescope (JWST). It will allow Near Infrared Spectrometer (NIRSpec) to acquire spectra of hundreds of objects simultaneously therefore increasing its efficiency tremendously. We have developed these programmable arrays that are based on Micro-Electro Mechanical Structures (MEMS) technology. The arrays are 2D addressable masks that can operate in cryogenic environment of JWST. Since the primary JWST science requires acquisition of spectra of extremely faint objects, it is important to provide very high contrast of the open to closed shutters. This high contrast is necessary to eliminate any possible contamination and confusion in the acquired spectra by unwanted objects. We have developed and built a test system for the microshutter array functional and optical characterization. This system is capable of measuring the contrast of the microshutter array both in visible and infrared light of the NIRSpec wavelength range while the arrays are in their working cryogenic environment. We have measured contrast ratio of several microshutter arrays and demonstrated that they satisfy and in many cases far exceed the NIRSpec contrast requirement value of 2000.

The Cognitive Visualization System with the Dynamic Projection of Multidimensional Data

NASA Astrophysics Data System (ADS)

Gorohov, V.; Vitkovskiy, V.

2008-08-01

The phenomenon of cognitive machine drawing consists in the generation on the screen the special graphic representations, which create in the brain of human operator entertainment means. These means seem man by aesthetically attractive and, thus, they stimulate its descriptive imagination, closely related to the intuitive mechanisms of thinking. The essence of cognitive effect lies in the fact that man receives the moving projection as pseudo-three-dimensional object characterizing multidimensional means in the multidimensional space. After the thorough qualitative study of the visual aspects of multidimensional means with the aid of the enumerated algorithms appears the possibility, using algorithms of standard machine drawing to paint the interesting user separate objects or the groups of objects. Then it is possible to again return to the dynamic behavior of the rotation of means for the purpose of checking the intuitive ideas of user about the clusters and the connections in multidimensional data. Is possible the development of the methods of cognitive machine drawing in combination with other information technologies, first of all with the packets of digital processing of images and multidimensional statistical analysis.

Performance impact of stop lists and morphological decomposition on word-word corpus-based semantic space models.

PubMed

Keith, Jeff; Westbury, Chris; Goldman, James

2015-09-01

Corpus-based semantic space models, which primarily rely on lexical co-occurrence statistics, have proven effective in modeling and predicting human behavior in a number of experimental paradigms that explore semantic memory representation. The most widely studied extant models, however, are strongly influenced by orthographic word frequency (e.g., Shaoul & Westbury, Behavior Research Methods, 38, 190-195, 2006). This has the implication that high-frequency closed-class words can potentially bias co-occurrence statistics. Because these closed-class words are purported to carry primarily syntactic, rather than semantic, information, the performance of corpus-based semantic space models may be improved by excluding closed-class words (using stop lists) from co-occurrence statistics, while retaining their syntactic information through other means (e.g., part-of-speech tagging and/or affixes from inflected word forms). Additionally, very little work has been done to explore the effect of employing morphological decomposition on the inflected forms of words in corpora prior to compiling co-occurrence statistics, despite (controversial) evidence that humans perform early morphological decomposition in semantic processing. In this study, we explored the impact of these factors on corpus-based semantic space models. From this study, morphological decomposition appears to significantly improve performance in word-word co-occurrence semantic space models, providing some support for the claim that sublexical information-specifically, word morphology-plays a role in lexical semantic processing. An overall decrease in performance was observed in models employing stop lists (e.g., excluding closed-class words). Furthermore, we found some evidence that weakens the claim that closed-class words supply primarily syntactic information in word-word co-occurrence semantic space models.

HTV-4 hatch closing

NASA Image and Video Library

2013-09-03

ISS036-E-039129 (3 Sept. 2013) --- European Space Agency astronaut Luca Parmitano, Expedition 36 flight engineer, closes the hatch in the vestibule between the International Space Station’s Harmony node and the Japanese "Kounotori" H2 Transfer Vehicle-4 (HTV-4) in preparation to release the HTV-4 ending its one-month stay at the space station. The automated resupply craft will be grappled by the Canadarm2, removed from the Harmony node and released for a destructive reentry into Earth’s atmosphere.

HTV-4 hatch closing

NASA Image and Video Library

2013-09-03

ISS036-E-039132 (3 Sept. 2013) --- European Space Agency astronaut Luca Parmitano and NASA astronaut Karen Nyberg, both Expedition 36 flight engineers, close the hatch in the vestibule between the International Space Station’s Harmony node and the Japanese "Kounotori" H2 Transfer Vehicle-4 (HTV-4) in preparation to release the HTV-4 ending its one-month stay at the space station. The automated resupply craft will be grappled by the Canadarm2, removed from the Harmony node and released for a destructive reentry into Earth’s atmosphere.

Consecutive Plate Acoustic Suppressor Apparatus and Methods

NASA Technical Reports Server (NTRS)

Doychak, Joseph (Inventor); Parrott, Tony L. (Inventor)

1993-01-01

An apparatus and method for suppressing acoustic noise utilizes consecutive plates, closely spaced to each other so as to exploit dissipation associated with sound propagation in narrow channels to optimize the acoustic resistance at a liner surface. The closely spaced plates can be utilized as high temperature structural materials for jet engines by constructing the plates from composite materials. Geometries of the plates, such as plate depth, shape, thickness, inter-plate spacing, arrangement, etc., can be selected to achieve bulk material-like behavior.

Hidden Surface Removal through Object Space Decomposition.

DTIC Science & Technology

1982-01-01

12 2.1 Methods of Subdividing the Object Space ..................................................... 14 2.2 Accessing...AC.AIIA TO5ASK FORCE MNT OF TECH WRIONT-PATTERSON AFB 0O4 P/O 1a/I 64100(6 SURFACE REMOVAL THROWN4 OBJECT SPACE 0(COMPOSIT109d.(U UiCLASIFIEC AFZITNl...Surface Removal Through Object Space THESlS/ J AJ;I Decomposition 6. PERFORMING ORG. REPORT NUMBER 7. AUTHOR() a. CONTRACT OR GRANT NUMBER(s) Robert

Tensionless Strings and Supersymmetric Sigma Models: Aspects of the Target Space Geometry

NASA Astrophysics Data System (ADS)

Bredthauer, Andreas

2007-01-01

In this thesis, two aspects of string theory are discussed, tensionless strings and supersymmetric sigma models. The equivalent to a massless particle in string theory is a tensionless string. Even almost 30 years after it was first mentioned, it is still quite poorly understood. We discuss how tensionless strings give rise to exact solutions to supergravity and solve closed tensionless string theory in the ten dimensional maximally supersymmetric plane wave background, a contraction of AdS(5)xS(5) where tensionless strings are of great interest due to their proposed relation to higher spin gauge theory via the AdS/CFT correspondence. For a sigma model, the amount of supersymmetry on its worldsheet restricts the geometry of the target space. For N=(2,2) supersymmetry, for example, the target space has to be bi-hermitian. Recently, with generalized complex geometry, a new mathematical framework was developed that is especially suited to discuss the target space geometry of sigma models in a Hamiltonian formulation. Bi-hermitian geometry is so-called generalized Kaehler geometry but the relation is involved. We discuss various amounts of supersymmetry in phase space and show that this relation can be established by considering the equivalence between the Hamilton and Lagrange formulation of the sigma model. In the study of generalized supersymmetric sigma models, we find objects that favor a geometrical interpretation beyond generalized complex geometry.

Assessment of DSN Communication Coverage for Space Missions to Potentially Hazardous Asteroids

NASA Technical Reports Server (NTRS)

Kegege, Obadiah; Bittner, David; Gati, Frank; Bhasin, Kul

2012-01-01

A communication coverage gap exists for Deep Space Network (DSN) antennas. This communication coverage gap is on the southern hemisphere, centered at approximate latitude of -47deg and longitude of -45deg. The area of this communication gap varies depending on the altitude from the Earth s surface. There are no current planetary space missions that fall within the DSN communication gap because planetary bodies in the Solar system lie near the ecliptic plane. However, some asteroids orbits are not confined to the ecliptic plane. In recent years, Potentially Hazardous Asteroids (PHAs) have passed within 100,000 km of the Earth. NASA s future space exploration goals include a manned mission to asteroids. It is important to ensure reliable and redundant communication coverage/capabilities for manned space missions to dangerous asteroids that make a sequence of close Earth encounters. In this paper, we will describe simulations performed to determine whether near-Earth objects (NEO) that have been classified as PHAs fall within the DSN communication coverage gap. In the study, we reviewed literature for a number of PHAs, generated binary ephemeris for selected PHAs using JPL s HORIZONS tool, and created their trajectories using Satellite Took Kit (STK). The results show that some of the PHAs fall within DSN communication coverage gap. This paper presents the simulation results and our analyses

Gross, Histologic, and Computed Tomographic Anatomy of the Lacrimal System of Snakes

PubMed Central

Souza, Nicole M.; Maggs, David J.; Park, Shin Ae; Puchalski, Sarah; Reilly, Christopher M.; Paul-Murphy, Joanne; Murphy, Christopher J.

2014-01-01

Objective To describe the lacrimal system of snakes using contrast micro-computed tomography (micro-CT) with 3-dimensional reconstruction, fluorescein passage (“Jones”) testing, histology, and gross dissection. Animals studied One Royal Python and 19 snake cadavers representing 10 species. Procedures Direct observation following injection of fluorescein into the subspectacular space, micro-CT following injection of 3 contrast agents into the subspectacular space, gross dissection following injection of latex into the subspectacular space, and histopathology. Results Injection of fluorescein confirmed patency but not course of the lacrimal duct. Barium enabled clear visualization of the lacrimal duct whereas two iodinated contrast agents proved inadequate. Collectively, micro-CT, anatomic dissections, and histology suggest tears are produced by a single, large, serous, retrobulbar gland, released into the subspectacular space via several ductules, and drained through a single punctum originating in the ventronasal subspectacular space and the lacrimal duct taking one of 3 routes of variable tortuosity before opening into the oral cavity in close association with the opening of the duct of the vomeronasal organ. Conclusions The ophidian lacrimal duct has a generally tortuous course and the details of its anatomy is species variable. The tortuous course of the duct likely predisposes snakes to duct occlusion and must be considered when planning medical and surgical interventions in snakes with pseudobuphthalmos and subspectacular abscessation. PMID:24862081

Modeling, Monitoring and Fault Diagnosis of Spacecraft Air Contaminants

NASA Technical Reports Server (NTRS)

Ramirez, W. Fred; Skliar, Mikhail; Narayan, Anand; Morgenthaler, George W.; Smith, Gerald J.

1998-01-01

Control of air contaminants is a crucial factor in the safety considerations of crewed space flight. Indoor air quality needs to be closely monitored during long range missions such as a Mars mission, and also on large complex space structures such as the International Space Station. This work mainly pertains to the detection and simulation of air contaminants in the space station, though much of the work is easily extended to buildings, and issues of ventilation systems. Here we propose a method with which to track the presence of contaminants using an accurate physical model, and also develop a robust procedure that would raise alarms when certain tolerance levels are exceeded. A part of this research concerns the modeling of air flow inside a spacecraft, and the consequent dispersal pattern of contaminants. Our objective is to also monitor the contaminants on-line, so we develop a state estimation procedure that makes use of the measurements from a sensor system and determines an optimal estimate of the contamination in the system as a function of time and space. The real-time optimal estimates in turn are used to detect faults in the system and also offer diagnoses as to their sources. This work is concerned with the monitoring of air contaminants aboard future generation spacecraft and seeks to satisfy NASA's requirements as outlined in their Strategic Plan document (Technology Development Requirements, 1996).

A Flux-Corrected Transport Based Hydrodynamic Model for the Plasmasphere Refilling Problem following Geomagnetic Storms

NASA Astrophysics Data System (ADS)

Chatterjee, K.; Schunk, R. W.

2017-12-01

The refilling of the plasmasphere following a geomagnetic storm remains one of the longstanding problems in the area of ionosphere-magnetosphere coupling. Both diffusion and hydrodynamic approximations have been adopted for the modeling and solution of this problem. The diffusion approximation neglects the nonlinear inertial term in the momentum equation and so this approximation is not rigorously valid immediately after the storm. Over the last few years, we have developed a hydrodynamic refilling model using the flux-corrected transport method, a numerical method that is extremely well suited to handling nonlinear problems with shocks and discontinuities. The plasma transport equations are solved along 1D closed magnetic field lines that connect conjugate ionospheres and the model currently includes three ion (H+, O+, He+) and two neutral (O, H) species. In this work, each ion species under consideration has been modeled as two separate streams emanating from the conjugate hemispheres and the model correctly predicts supersonic ion speeds and the presence of high levels of Helium during the early hours of refilling. The ultimate objective of this research is the development of a 3D model for the plasmasphere refilling problem and with additional development, the same methodology can potentially be applied to the study of other complex space plasma coupling problems in closed flux tube geometries. Index Terms: 2447 Modeling and forecasting [IONOSPHERE] 2753 Numerical modeling [MAGNETOSPHERIC PHYSICS] 7959 Models [SPACE WEATHER

14 CFR 431.85 - Registration of space objects.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Registration of space objects. 431.85 Section 431.85 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... Requirements-Reusable Launch Vehicle Mission License Terms and Conditions § 431.85 Registration of space...

14 CFR 431.85 - Registration of space objects.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Registration of space objects. 431.85 Section 431.85 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... Requirements-Reusable Launch Vehicle Mission License Terms and Conditions § 431.85 Registration of space...

14 CFR 431.85 - Registration of space objects.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Registration of space objects. 431.85 Section 431.85 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... Requirements-Reusable Launch Vehicle Mission License Terms and Conditions § 431.85 Registration of space...

14 CFR 431.85 - Registration of space objects.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Registration of space objects. 431.85 Section 431.85 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... Requirements-Reusable Launch Vehicle Mission License Terms and Conditions § 431.85 Registration of space...

14 CFR 431.85 - Registration of space objects.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Registration of space objects. 431.85 Section 431.85 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... Requirements-Reusable Launch Vehicle Mission License Terms and Conditions § 431.85 Registration of space...

Monitoring ethylene emissions from plants cultured for a controlled ecological life support system

NASA Technical Reports Server (NTRS)

Corey, Kenneth A.

1995-01-01

Emission of hydrocarbons and other volatile compounds by materials and organisms in closed environments will be a major concern in the design and management of advanced life support systems with a bioregenerative component. Ethylene, a simple hydrocarbon synthesized by plants, is involved in the elicitation of a wide range of physiological responses. In closed environments, ethylene may build up to levels which become physiologically active. In several growouts of 'Yecora Rojo' wheat in Kennedy Space Center's Biomass Production Chamber (BPC), it was observed that leaf flecking and rolling occurred in the sealed environment and was virtually eliminated when potassium permanganate was used to scrub the atmospheric environment. It was suggested that ethylene, which accumulated to about 60 ppb in the chamber and which was effectively absorbed by potassium permanganate, was responsible for the symptoms. The objectives of this work were to: (1) determine rates of ethylene evolution from lettuce (Lactuca sativa cultivar Waldemann's Green) and wheat (Triticum aestivum cultivar Yecora Rojo) plants during growth and development; (2) determine the effects of exposure of whole, vegetative stage plants to exogenous ethylene concentrations in the range of what would develop in closed environment growth chambers; and (3) develop predictive functions for changes in ethylene concentration that would develop under different cropping and closed environment configurations. Results will lead to the development of management strategies for ethylene in bioregenerative life support systems.

A neuroanatomical model of space-based and object-centered processing in spatial neglect.

PubMed

Pedrazzini, Elena; Schnider, Armin; Ptak, Radek

2017-11-01

Visual attention can be deployed in space-based or object-centered reference frames. Right-hemisphere damage may lead to distinct deficits of space- or object-based processing, and such dissociations are thought to underlie the heterogeneous nature of spatial neglect. Previous studies have suggested that object-centered processing deficits (such as in copying, reading or line bisection) result from damage to retro-rolandic regions while impaired spatial exploration reflects damage to more anterior regions. However, this evidence is based on small samples and heterogeneous tasks. Here, we tested a theoretical model of neglect that takes in account the space- and object-based processing and relates them to neuroanatomical predictors. One hundred and one right-hemisphere-damaged patients were examined with classic neuropsychological tests and structural brain imaging. Relations between neglect measures and damage to the temporal-parietal junction, intraparietal cortex, insula and middle frontal gyrus were examined with two structural equation models by assuming that object-centered processing (involved in line bisection and single-word reading) and space-based processing (involved in cancelation tasks) either represented a unique latent variable or two distinct variables. Of these two models the latter had better explanatory power. Damage to the intraparietal sulcus was a significant predictor of object-centered, but not space-based processing, while damage to the temporal-parietal junction predicted space-based, but not object-centered processing. Space-based processing and object-centered processing were strongly intercorrelated, indicating that they rely on similar, albeit partly dissociated processes. These findings indicate that object-centered and space-based deficits in neglect are partly independent and result from superior parietal and inferior parietal damage, respectively.

Confinement has no effect on visual space perception: The results of the Mars-500 experiment.

PubMed

Sikl, Radovan; Simeček, Michal

2014-02-01

People confined to a closed space live in a visual environment that differs from a natural open-space environment in several respects. The view is restricted to no more than a few meters, and nearby objects cannot be perceived relative to the position of a horizon. Thus, one might expect to find changes in visual space perception as a consequence of the prolonged experience of confinement. The subjects in our experimental study were participants of the Mars-500 project and spent nearly a year and a half isolated from the outside world during a simulated mission to Mars. The participants were presented with a battery of computer-based psychophysical tests examining their performance on various 3-D perception tasks, and we monitored changes in their perceptual performance throughout their confinement. Contrary to our expectations, no serious effect of the confinement on the crewmembers' 3-D perception was observed in any experiment. Several interpretations of these findings are discussed, including the possibilities that (1) the crewmembers' 3-D perception really did not change significantly, (2) changes in 3-D perception were manifested in the precision rather than the accuracy of perceptual judgments, and/or (3) the experimental conditions and the group sample were problematic.

Laser Range and Bearing Finder for Autonomous Missions

NASA Technical Reports Server (NTRS)

Granade, Stephen R.

2004-01-01

NASA has recently re-confirmed their interest in autonomous systems as an enabling technology for future missions. In order for autonomous missions to be possible, highly-capable relative sensor systems are needed to determine an object's distance, direction, and orientation. This is true whether the mission is autonomous in-space assembly, rendezvous and docking, or rover surface navigation. Advanced Optical Systems, Inc. has developed a wide-angle laser range and bearing finder (RBF) for autonomous space missions. The laser RBF has a number of features that make it well-suited for autonomous missions. It has an operating range of 10 m to 5 km, with a 5 deg field of view. Its wide field of view removes the need for scanning systems such as gimbals, eliminating moving parts and making the sensor simpler and space qualification easier. Its range accuracy is 1% or better. It is designed to operate either as a stand-alone sensor or in tandem with a sensor that returns range, bearing, and orientation at close ranges, such as NASA's Advanced Video Guidance Sensor. We have assembled the initial prototype and are currently testing it. We will discuss the laser RBF's design and specifications. Keywords: laser range and bearing finder, autonomous rendezvous and docking, space sensors, on-orbit sensors, advanced video guidance sensor

Multiscale approach to contour fitting for MR images

NASA Astrophysics Data System (ADS)

Rueckert, Daniel; Burger, Peter

1996-04-01

We present a new multiscale contour fitting process which combines information about the image and the contour of the object at different levels of scale. The algorithm is based on energy minimizing deformable models but avoids some of the problems associated with these models. The segmentation algorithm starts by constructing a linear scale-space of an image through convolution of the original image with a Gaussian kernel at different levels of scale, where the scale corresponds to the standard deviation of the Gaussian kernel. At high levels of scale large scale features of the objects are preserved while small scale features, like object details as well as noise, are suppressed. In order to maximize the accuracy of the segmentation, the contour of the object of interest is then tracked in scale-space from coarse to fine scales. We propose a hybrid multi-temperature simulated annealing optimization to minimize the energy of the deformable model. At high levels of scale the SA optimization is started at high temperatures, enabling the SA optimization to find a global optimal solution. At lower levels of scale the SA optimization is started at lower temperatures (at the lowest level the temperature is close to 0). This enforces a more deterministic behavior of the SA optimization at lower scales and leads to an increasingly local optimization as high energy barriers cannot be crossed. The performance and robustness of the algorithm have been tested on spin-echo MR images of the cardiovascular system. The task was to segment the ascending and descending aorta in 15 datasets of different individuals in order to measure regional aortic compliance. The results show that the algorithm is able to provide more accurate segmentation results than the classic contour fitting process and is at the same time very robust to noise and initialization.

Visualizing Similarity of Appearance by Arrangement of Cards

PubMed Central

Nakatsuji, Nao; Ihara, Hisayasu; Seno, Takeharu; Ito, Hiroshi

2016-01-01

This study proposes a novel method to extract the configuration of the psychological space by directly measuring subjects' similarity rating without computational work. Although multidimensional scaling (MDS) is well-known as a conventional method for extracting the psychological space, the method requires many pairwise evaluations. The times taken for evaluations increase in proportion to the square of the number of objects in MDS. The proposed method asks subjects to arrange cards on a poster sheet according to the degree of similarity of the objects. To compare the performance of the proposed method with the conventional one, we developed similarity maps of typefaces through the proposed method and through non-metric MDS. We calculated the trace correlation coefficient among all combinations of the configuration for both methods to evaluate the degree of similarity in the obtained configurations. The threshold value of trace correlation coefficient for statistically discriminating similar configuration was decided based on random data. The ratio of the trace correlation coefficient exceeding the threshold value was 62.0% so that the configurations of the typefaces obtained by the proposed method closely resembled those obtained by non-metric MDS. The required duration for the proposed method was approximately one third of the non-metric MDS's duration. In addition, all distances between objects in all the data for both methods were calculated. The frequency for the short distance in the proposed method was lower than that of the non-metric MDS so that a relatively small difference was likely to be emphasized among objects in the configuration by the proposed method. The card arrangement method we here propose, thus serves as a easier and time-saving tool to obtain psychological structures in the fields related to similarity of appearance. PMID:27242611

An approach to ground based space surveillance of geostationary on-orbit servicing operations

NASA Astrophysics Data System (ADS)

Scott, Robert (Lauchie); Ellery, Alex

2015-07-01

On Orbit Servicing (OOS) is a class of dual-use robotic space missions that could potentially extend the life of orbiting satellites by fuel replenishment, repair, inspection, orbital maintenance or satellite repurposing, and possibly reduce the rate of space debris generation. OOS performed in geostationary orbit poses a unique challenge for the optical space surveillance community. Both satellites would be performing proximity operations in tight formation flight with separations less than 500 m making atmospheric seeing (turbulence) a challenge to resolving a geostationary satellite pair when viewed from the ground. The two objects would appear merged in an image as the resolving power of the telescope and detector, coupled with atmospheric seeing, limits the ability to resolve the two objects. This poses an issue for obtaining orbital data for conjunction flight safety or, in matters pertaining to space security, inferring the intent and trajectory of an unexpected object perched very close to one's satellite asset on orbit. In order to overcome this problem speckle interferometry using a cross spectrum approach is examined as a means to optically resolve the client and servicer's relative positions to enable a means to perform relative orbit determination of the two spacecraft. This paper explores cases where client and servicing satellites are in unforced relative motion flight and examines the observability of the objects. Tools are described that exploit cross-spectrum speckle interferometry to (1) determine the presence of a secondary in the vicinity of the client satellite and (2) estimate the servicing satellite's motion relative to the client. Experimental observations performed with the Mont Mégantic 1.6 m telescope on co-located geostationary satellites (acting as OOS proxy objects) are described. Apparent angular separations between Anik G1 and Anik F1R from 5 to 1 arcsec were observed as the two satellites appeared to graze one another. Data reduction using differential angular measurements derived from speckle images collected by the 1.6 m telescope produced relative orbit estimates with better than 90 m accuracy in the cross-track and in-track directions but exhibited highly variable behavior in the radial component from 50 to 1800 m. Simulations of synthetic tracking data indicated that the radial component requires approximately six hours of tracking data for an Extended Kalman Filter to converge on an relative orbit estimate with less than 100 m overall uncertainty. The cross-spectrum approach takes advantage of the Fast Fourier Transform (FFT) permitting near real-time estimation of the relative orbit of the two satellites. This also enables the use of relatively larger detector arrays (>106 pixels) helping to ease acquisition process to acquire optical angular data.

Space life sciences: Programs and projects

NASA Technical Reports Server (NTRS)

1989-01-01

NASA space life science activities are outlined. Brief, general descriptions are given of research in the areas of biomedical research, space biology, closed loop life support systems, exobiology, and biospherics.

NASA's Webb Telescope "chilling out" in Houston for the summer

NASA Image and Video Library

2017-12-08

NASA’s James Webb Space Telescope was placed in Johnson Space Center’s historic Chamber A on June 20, 2017, to prepare for its final three months of testing in a cryogenic vacuum that mimics temperatures in space. Engineers will perform the test to prove that the telescope can operate in space at these temperatures. Chamber A will simulate an environment where the telescope will experience extreme cold -- around 37 Kelvin (minus 236 degrees Celsius or minus 393 degrees Fahrenheit). In space, the telescope must be kept extremely cold, in order to be able to detect the infrared light from very faint, distant objects. To protect the telescope from external sources of light and heat (like the sun, Earth, and moon), as well as from heat emitted by the observatory, a five-layer, tennis court-sized sunshield acts like a parasol that provides shade. The sunshield separates the observatory into a warm, sun-facing side (reaching temperatures close to 400 degrees Fahrenheit) and a cold side (185 degrees below zero). The sunshield blocks sunlight from interfering with the sensitive telescope instruments. Read more: go.nasa.gov/2sZAilS NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

The Asteroid Redirect Mission (ARM): Exploration of a Former Binary NEA?

NASA Technical Reports Server (NTRS)

Abell, P. A.; Mazanek, D. D.; Reeves, D. M.; Chodas, P. W.; Gates, M. M.; Johnson, L. N.; Ticker, R. L.

2016-01-01

The National Aeronautics and Space Administration (NASA) is developing the Asteroid Redirect Mission (ARM) as a capability demonstration for future human exploration, including use of high-power solar electric propulsion, which allows for the efficient movement of large masses through deep space. The ARM will also demonstrate the capability to conduct proximity operations with natural space objects and crewed operations beyond the security of quick Earth return. The Asteroid Redirect Robotic Mission (ARRM), currently in formulation, will visit a large near-Earth asteroid (NEA), collect a multi-ton boulder from its surface, conduct a demonstration of a slow push planetary defense technique, and redirect the multi-ton boulder into a stable orbit around the Moon. Once returned to cislunar space in the mid-2020s, astronauts aboard an Orion spacecraft will dock with the robotic vehicle to explore the boulder and return samples to Earth. The ARM is part of NASA's plan to advance technologies, capabilities, and spaceflight experience needed for a human mission to the Martian system in the 2030s. The ARM and subsequent availability of the asteroidal material in cis-lunar space, provide significant opportunities to advance our knowledge of small bodies in the synergistic areas of science, planetary defense, and in-situ resource utilization (ISRU). The current reference target for the ARM is NEA (341843) 2008 EV5, which may have been the primary body of a former binary system (Busch et al., 2011; Tardivel et al., 2016). The ARRM will perform several close proximity operations to investigate the NEA and map its surface. A detailed investigation of this object may allow a better understanding of binary NEA physical characteristics and the possible outcomes for their evolution. An overview of the ARM robotic and crewed segments, including mission operations, and a discussion of potential opportunities for participation with the ARM will be provided in this presentation.

Toward Microsatellite Based Space Situational Awareness

NASA Astrophysics Data System (ADS)

Scott, L.; Wallace, B.; Sale, M.; Thorsteinson, S.

2013-09-01

The NEOSSat microsatellite is a dual mission space telescope which will perform asteroid detection and Space Situational Awareness (SSA) observation experiments on deep space, earth orbiting objects. NEOSSat was launched on 25 February 2013 into a 800 dawn-dusk sun synchronous orbit and is currently undergoing satellite commissioning. The microsatellite consists of a small aperture optical telescope, GPS receiver, high performance attitude control system, and stray light rejection baffle designed to reject stray light from the Sun while searching for asteroids with elongations 45 degrees along the ecliptic. The SSA experimental mission, referred to as HEOSS (High Earth Orbit Space Surveillance), will focus on objects in deep space orbits. The HEOSS mission objective is to evaluate the utility of microsatellites to perform catalog maintenance observations of resident space objects in a manner consistent with the needs of the Canadian Forces. The advantages of placing a space surveillance sensor in low Earth orbit are that the observer can conduct observations without the day-night interruption cycle experienced by ground based telescopes, the telescope is insensitive to adverse weather and the system has visibility to deep space resident space objects which are not normally visible from ground based sensors. Also, from a photometric standpoint, the microsatellite is able to conduct observations on objects with a rapidly changing observer position. The possibility of spin axis estimation on geostationary satellites may be possible and an experiment characterize spin axis of distant resident space objects is being planned. Also, HEOSS offers the ability to conduct observations of satellites at high phase angles which can potentially extend the trackable portion of space in which deep space objects' orbits can be monitored. In this paper we describe the HEOSS SSA experimental data processing system and the preliminary findings of the catalog maintenance experiments. The placement of a space based space surveillance sensor in low Earth orbit introduces tasking and image processing complexities such as cosmic ray rejection, scattered light from Earth's limb and unique scheduling limitations due to the observer's rapid positional change and we describe first-look microsatellite space surveillance lessons from this unique orbital vantage point..

Radar systems for a polar mission, volume 1

NASA Technical Reports Server (NTRS)

Moore, R. K.; Claassen, J. P.; Erickson, R. L.; Fong, R. K. T.; Komen, M. J.; Mccauley, J.; Mcmillan, S. B.; Parashar, S. K.

1977-01-01

The application of synthetic aperture radar (SAR) in monitoring and managing earth resources is examined. Synthetic aperture radars form a class of side-looking airborne radar, often referred to as coherent SLAR, which permits fine-resolution radar imagery to be generated at long operating ranges by the use of signal processing techniques. By orienting the antenna beam orthogonal to the motion of the spacecraft carrying the radar, a one-dimensional imagery ray system is converted into a two-dimensional or terrain imaging system. The radar's ability to distinguish - or resolve - closely spaced transverse objects is determined by the length of the pulse. The transmitter components receivers, and the mixer are described in details.

Lessons learned and their application to program development and cultural issues

NASA Technical Reports Server (NTRS)

Roth, Gilbert L.

1991-01-01

The main objectives of space product assurance are, in effect, the same as those of Total Quality Management (TQM) or its many variants. The most significant ingredients are the lessons learned and their application to ongoing and future programs as they are affected by changes in the cultural environment. The cultural issues which affect almost everything done in technical programs and projects are considered. Understanding the lessons learned and the synergism which results from this combination of knowledge, culture, and lessons learned is identified as crucial. A brief discussion of the closed loop linkage that should exist between the world of hands on activities and that of educational institutions is presented.

Migration of comets to the terrestrial planets

NASA Astrophysics Data System (ADS)

Ipatov, Sergei I.; Mather, John C.

2007-05-01

The orbital evolution of 30,000 objects with initial orbits close to those of Jupiter-family comets (JFCs) and also of 15,000 dust particles was integrated [1-3]. For initial orbital elements close to those of Comets 2P, 10P, 44P, and 113P, a few objects got Earth-crossing orbits with semi-major axes a<2 AU and aphelion distances Q<4.2 AU, or even got inner-Earth (Q<0.983 AU), Aten, or typical asteroidal orbits, and moved in such orbits for more than 1 Myr (up to tens or even hundreds of Myrs). Most of former trans-Neptunian objects that have typical near-Earth object (NEO) orbits moved in such orbits for Myrs, so during most of this time they were extinct comets. From a dynamical point of view, the fraction of extinct comets among NEOs can exceed several tens of percent, but, probably, many extinct comets disintegrated into mini-comets and dust during a smaller part of their dynamical lifetimes if these lifetimes were large. The probability of the collision of Comet 10P with the Earth during a dynamical lifetime of the comet was P[E]≈1.4•10-4, but 80% of this mean probability was due only to one object among 2600 considered objects with orbits close to that of Comet 10P. For runs for Comet 2P, P[E]≈(1-5)•10-4. For most other considered JFCs, 10-6 < P[E] < 10-5. For Comets 22P and 39P, P[E]≈ (1-2)•10-6; and for Comets 9P, 28P and 44P, P[E]≈(2-5)•10-6. For all considered JFCs, P[E]>4•10-6. The Bulirsh-Stoer method of integration and a symplectic method gave similar results. In our runs the probability of a collision of one object with the Earth could be greater than the sum of probabilities for thousands of other objects. The ratios of probabilities of collisions of JFCs with Venus and Mars to the mass of a planet usually were not smaller than that for Earth. For dust particles started from comets and asteroids, P[E ]was maximum for diameters d~100 μm. These maximum values of P [E] were usually (exclusive for 2P) greater at least by an order of magnitude than the values for parent comets. [1] Ipatov S.I. and Mather J.C. (2004) Annals of the New York Acad. of Sci., v. 1017, 46-65. [2] Ipatov S.I. et al. (2004) Annals of the New York Acad. of Sci., v. 1017, 66-80. [3] Ipatov S.I. and Mather J.C. (2006) Adv. in Space Res., v. 37, N 1, 126-137.

Dynamics and control of robot for capturing objects in space

NASA Astrophysics Data System (ADS)

Huang, Panfeng

Space robots are expected to perform intricate tasks in future space services, such as satellite maintenance, refueling, and replacing the orbital replacement unit (ORU). To realize these missions, the capturing operation may not be avoided. Such operations will encounter some challenges because space robots have some unique characteristics unfound on ground-based robots, such as, dynamic singularities, dynamic coupling between manipulator and space base, limited energy supply and working without a fixed base, and so on. In addition, since contacts and impacts may not be avoided during capturing operation. Therefore, dynamics and control problems of space robot for capturing objects are significant research topics if the robots are to be deployed for the space services. A typical servicing operation mainly includes three phases: capturing the object, berthing and docking the object, then repairing the target. Therefore, this thesis will focus on resolving some challenging problems during capturing the object, berthing and docking, and so on. In this thesis, I study and analyze the dynamics and control problems of space robot for capturing objects. This work has potential impact in space robotic applications. I first study the contact and impact dynamics of space robot and objects. I specifically focus on analyzing the impact dynamics and mapping the relationship of influence and speed. Then, I develop the fundamental theory for planning the minimum-collision based trajectory of space robot and designing the configuration of space robot at the moment of capture. To compensate for the attitude of the space base during the capturing approach operation, a new balance control concept which can effectively balance the attitude of the space base using the dynamic couplings is developed. The developed balance control concept helps to understand of the nature of space dynamic coupling, and can be readily applied to compensate or minimize the disturbance to the space base. After capturing the object, the space robot must complete the following two tasks: one is to berth the object, and the other is to re-orientate the attitude of the whole robot system for communication and power supply. Therefore, I propose a method to accomplish these two tasks simultaneously using manipulator motion only. The ultimate goal of space services is to realize the capture and manipulation autonomously. Therefore, I propose an affective approach based on learning human skill to track and capture the objects automatically in space. With human-teaching demonstration, the space robot is able to learn and abstract human tracking and capturing skill using an efficient neural-network learning architecture that combines flexible Cascade Neural Networks with Node Decoupled Extended Kalman Filtering (CNN-NDEKF). The simulation results attest that this approach is useful and feasible in tracking trajectory planning and capturing of space robot. Finally I propose a novel approach based on Genetic Algorithms (GAs) to optimize the approach trajectory of space robots in order to realize effective and stable operations. I complete the minimum-torque path planning in order to save the limited energy in space, and design the minimum jerk trajectory for the stabilization of the space manipulator and its space base. These optimal algorithms are very important and useful for the application of space robot.

Qualitative differences in memory for vista and environmental spaces are caused by opaque borders, not movement or successive presentation.

PubMed

Meilinger, Tobias; Strickrodt, Marianne; Bülthoff, Heinrich H

2016-10-01

Two classes of space define our everyday experience within our surrounding environment: vista spaces, such as rooms or streets which can be perceived from one vantage point, and environmental spaces, for example, buildings and towns which are grasped from multiple views acquired during locomotion. However, theories of spatial representations often treat both spaces as equal. The present experiments show that this assumption cannot be upheld. Participants learned exactly the same layout of objects either within a single room or spread across multiple corridors. By utilizing a pointing and a placement task we tested the acquired configurational memory. In Experiment 1 retrieving memory of the object layout acquired in environmental space was affected by the distance of the traveled path and the order in which the objects were learned. In contrast, memory retrieval of objects learned in vista space was not bound to distance and relied on different ordering schemes (e.g., along the layout structure). Furthermore, spatial memory of both spaces differed with respect to the employed reference frame orientation. Environmental space memory was organized along the learning experience rather than layout intrinsic structure. In Experiment 2 participants memorized the object layout presented within the vista space room of Experiment 1 while the learning procedure emulated environmental space learning (movement, successive object presentation). Neither factor rendered similar results as found in environmental space learning. This shows that memory differences between vista and environmental space originated mainly from the spatial compartmentalization which was unique to environmental space learning. Our results suggest that transferring conclusions from findings obtained in vista space to environmental spaces and vice versa should be made with caution. Copyright © 2016 Elsevier B.V. All rights reserved.

Application of Multi-Hypothesis Sequential Monte Carlo for Breakup Analysis

NASA Astrophysics Data System (ADS)

Faber, W. R.; Zaidi, W.; Hussein, I. I.; Roscoe, C. W. T.; Wilkins, M. P.; Schumacher, P. W., Jr.

As more objects are launched into space, the potential for breakup events and space object collisions is ever increasing. These events create large clouds of debris that are extremely hazardous to space operations. Providing timely, accurate, and statistically meaningful Space Situational Awareness (SSA) data is crucial in order to protect assets and operations in space. The space object tracking problem, in general, is nonlinear in both state dynamics and observations, making it ill-suited to linear filtering techniques such as the Kalman filter. Additionally, given the multi-object, multi-scenario nature of the problem, space situational awareness requires multi-hypothesis tracking and management that is combinatorially challenging in nature. In practice, it is often seen that assumptions of underlying linearity and/or Gaussianity are used to provide tractable solutions to the multiple space object tracking problem. However, these assumptions are, at times, detrimental to tracking data and provide statistically inconsistent solutions. This paper details a tractable solution to the multiple space object tracking problem applicable to space object breakup events. Within this solution, simplifying assumptions of the underlying probability density function are relaxed and heuristic methods for hypothesis management are avoided. This is done by implementing Sequential Monte Carlo (SMC) methods for both nonlinear filtering as well as hypothesis management. This goal of this paper is to detail the solution and use it as a platform to discuss computational limitations that hinder proper analysis of large breakup events.

Healing environments in cancer treatment and care. Relations of space and practice in hematological cancer treatment.

PubMed

Høybye, Mette Terp

2013-02-01

Given the growing attention to the importance of design in shaping healing hospital environments this study extends the understanding of healing environments, beyond causal links between environmental exposure and health outcome by elucidating how environments and practices interrelate. The study was conducted as an ethnographic fieldwork from March 2011 to September 2011 at the Department of Haematology at Odense University Hospital, Denmark, systematically using participant observation and interviews as research strategies. It included 20 patients, four of who were followed closely over an extended time period. Through thematic analysis five key concepts emerged about the social dynamics of hospital environments: practices of self; creating personal space; social recognition; negotiating space; and ambiguity of space and care. Through these concepts, the study demonstrates how the hospital environment is a flow of relations between space and practice that changes and challenges a structural idea of design and healing. Patients' sense of healing changes with the experience of progression in treatment and the capacity of the hospital space to incite an experience of homeliness and care. Furthermore, cancer patients continuously challenge the use and limits of space by individual objects and practices of privacy and home. Healing environments are complex relations between practices, space and care, where recognition of the individual patient's needs, values and experiences is key to developing the environment to support the patient quality of life. The present study holds implications for practice to inform design of future hospital environments for cancer treatment. The study points to the importance for being attentive to the need for flexible spaces in hospitals that recognize the dynamics of healing, by providing individualized care, relating to the particular and changing needs of patients supporting their potential and their challenged condition with the best care possible.

DISTANT CLUSTER OF GALAXIES [left

NASA Technical Reports Server (NTRS)

2002-01-01

One of the deepest images to date of the universe, taken with NASA's Hubble Space Telescope (HST), reveals thousands of faint galaxies at the detection limit of present day telescopes. Peering across a large volume of the observable cosmos, Hubble resolves thousands of galaxies from five to twelve billion light-years away. The light from these remote objects has taken billions of years to cross the expanding universe, making these distant galaxies fossil evidence' of events that happened when the universe was one-third its present age. A fraction of the galaxies in this image belong to a cluster located nine billion light-years away. Though the field of view (at the cluster's distance) is only two million light-years across, it contains a multitude of fragmentary objects. (By comparison, the two million light-years between our Milky Way galaxy and its nearest large companion galaxy, in the constellation Andromeda, is essentially empty space!) Very few of the cluster's members are recognizable as normal spiral galaxies (like our Milky Way), although some elongated members might be edge-on disks. Among this zoo of odd galaxies are ``tadpole-like'' objects, disturbed and apparently merging systems dubbed 'train-wrecks,' and a multitude of faint, tiny shards and fragments, dwarf galaxies or possibly an unknown population of objects. However, the cluster also contains red galaxies that resemble mature examples of today's elliptical galaxies. Their red color comes from older stars that must have formed shortly after the Big Bang. The image is the full field view of the Wide Field and Planetary Camera-2. The picture was taken in intervals between May 11 and June 15, 1994 and required an 18-hour long exposure, over 32 orbits of HST, to reveal objects down to 29th magnitude. [bottom right] A close up view of the peculiar radio galaxy 3C324 used to locate the cluster. The galaxy is nine billion light-years away as measured by its spectral redshift (z=1.2), and located in the constellation Serpens. Based on the colors and the statistical distribution of the galaxies in 3C 324's vicinity, astronomers conclude a remote cluster is at the same distance as a radio galaxy. [center right] This pair of elliptical galaxies, seen together with a few fainter companions, is remarkably similar in shape, light distribution, and color to their present day descendants. This Hubble image provides evidence that ellipticals formed remarkably early in the universe. [top right] Some of the objects in this compact tangled group resemble today's spiral galaxies. However, they have irregular shapes and appear disrupted and asymmetric. This might be due to a high frequency of galaxy collisions and close encounters in the early universe. Credit: Mark Dickinson (STScI) and NASA

Closeup view looking forward along the centerline of the Orbiter ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Close-up view looking forward along the centerline of the Orbiter Discovery looking into the payload bay. This view is a close-up view of the external airlock and the beam-truss attach structure supporting it and attaching it to the payload bay sill longerons. Also note the protective covering over the docking mechanism on top of the airlock assembly. This external airlock configuration was for mating to the International Space Station. This photograph was taken in the Orbiter Processing Facility at Kennedy Space Cente - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

KSC-2012-5549

NASA Image and Video Library

2012-09-20

CAPE CANAVERAL, Fla. – Inside Orbiter Processing Facility-2 at NASA’s Kennedy Space Center in Florida, workers watch as the left payload bay door begins to close on space shuttle Atlantis. Both payload bay doors will be closed for the final time. The orbiter is undergoing final preparations for its transfer to the Kennedy Space Center Visitor complex targeted for November. The work is part of Transition and Retirement of the remaining shuttle. Atlantis is being prepared for public display at the visitor complex. Over the course of its 26-year career, Atlantis spent 293 days in space during 33 missions. For more information, visit http://www.nasa.gov/transition. Photo credit: NASA/Jim Grossmann

KSC-2012-5550

NASA Image and Video Library

2012-09-20

CAPE CANAVERAL, Fla. – Inside Orbiter Processing Facility-2 at NASA’s Kennedy Space Center in Florida, space shuttle Atlantis’ left payload bay door has been closed. Both payload bay doors will be closed for the final time. The orbiter is undergoing final preparations for its transfer to the Kennedy Space Center Visitor complex targeted for November. The work is part of Transition and Retirement of the remaining shuttle. Atlantis is being prepared for public display at the visitor complex. Over the course of its 26-year career, Atlantis spent 293 days in space during 33 missions. For more information, visit http://www.nasa.gov/transition. Photo credit: NASA/Jim Grossmann

The Study of Indicatrices of Space Object Coatings in a Controlled Laboratory Environment

NASA Astrophysics Data System (ADS)

Koshkin, N.; Burlak, N.; Petrov, M.; Strakhova, S.

The indicatrices of light scattering by radiation balance coatings used on space objects (SO) were determined in the laboratory experiment in a controlled condition. The laboratory device for the physical simulation of photometric observations of space objects in orbit, which was used in this case to study optical properties of coating samples, is described. The features of light reflection off plane coating samples, including multi-layer insulation (MLI) blankets, metal surfaces coated with several layers of enamel EP-140, special polyacrylate enamel AK-512 and matte finish Tp-CO-2, were determined. The indicated coatings are compound reflectors which exhibit both diffuse and specular reflections. The data obtained are to be used in the development of computer optical-geometric models of space objects or their fragments (space debris) to interpret the photometry results for real space objects.

A Study on Re-entry Predictions of Uncontrolled Space Objects for Space Situational Awareness

NASA Astrophysics Data System (ADS)

Choi, Eun-Jung; Cho, Sungki; Lee, Deok-Jin; Kim, Siwoo; Jo, Jung Hyun

2017-12-01

The key risk analysis technologies for the re-entry of space objects into Earth’s atmosphere are divided into four categories: cataloguing and databases of the re-entry of space objects, lifetime and re-entry trajectory predictions, break-up models after re-entry and multiple debris distribution predictions, and ground impact probability models. In this study, we focused on re- entry prediction, including orbital lifetime assessments, for space situational awareness systems. Re-entry predictions are very difficult and are affected by various sources of uncertainty. In particular, during uncontrolled re-entry, large spacecraft may break into several pieces of debris, and the surviving fragments can be a significant hazard for persons and properties on the ground. In recent years, specific methods and procedures have been developed to provide clear information for predicting and analyzing the re-entry of space objects and for ground-risk assessments. Representative tools include object reentry survival analysis tool (ORSAT) and debris assessment software (DAS) developed by National Aeronautics and Space Administration (NASA), spacecraft atmospheric re-entry and aerothermal break-up (SCARAB) and debris risk assessment and mitigation analysis (DRAMA) developed by European Space Agency (ESA), and semi-analytic tool for end of life analysis (STELA) developed by Centre National d’Etudes Spatiales (CNES). In this study, various surveys of existing re-entry space objects are reviewed, and an efficient re-entry prediction technique is suggested based on STELA, the life-cycle analysis tool for satellites, and DRAMA, a re-entry analysis tool. To verify the proposed method, the re-entry of the Tiangong-1 Space Lab, which is expected to re-enter Earth’s atmosphere shortly, was simulated. Eventually, these results will provide a basis for space situational awareness risk analyses of the re-entry of space objects.

Commercial crew astronauts on This Week @NASA – July 10, 2015

NASA Image and Video Library

2015-07-10

NASA has selected four astronauts to work closely with two U.S. commercial companies that will return human spaceflight launches to Florida’s Space Coast. NASA named veteran astronauts and experienced test pilots Robert Behnken, Eric Boe, Douglas Hurley and Sunita Williams to work closely with Boeing and SpaceX. NASA contracted with Boeing and SpaceX to develop crew transportation systems and provide crew transportation services to and from the International Space Station. The agency will select the commercial crew astronauts from this group of four for the first test, which is scheduled for 2017. Also, NASA’s newest astronauts, New Horizons still on track, Benefits for Humanity, Cargo ship arrives at space station, Training continues for next ISS crew and more!

AEOLUS mission: the latest preparations before launch

NASA Astrophysics Data System (ADS)

Culoma, A.; Elfving, A.; Meynart, R.; Straume, A.; Wernham, D.

2017-09-01

The European Space Agency is developing a direct detection Doppler Wind Lidar for measuring wind profiles from space. The main objective of Aeolus is to provide tropospheric and lower stratospheric wind profiles globally for the improvement of weather forecast on short and medium term. Aeolus data are expected to greatly contribute to weather and air quality monitoring and to scientific advances in atmospheric dynamics. The UV Lidar instrument, ALADIN, will deliver horizontally-projected single line-of-sight wind profiles from the Doppler shift of molecular and particle backscatter. The development of the AEOLUS mission passed a major milestone with the integration of the full instrument and its functional and performance tests in 2016 and a 6-month life test of the spare UV laser transmitter. The satellite has been assembled and has successfully been subjected to a programme of functional and environmental (vibration, acoustic, shock, EMC) tests. The preparation of thermal vacuum testing, including instrument performance in vacuum, is close to completion.

Use of the Moon for spacecraft calibration over 350-2500 nm

USGS Publications Warehouse

Kieffer, H.H.; Anderson, J.M.

1998-01-01

The Moon is the only natural object outside the Earth's atmosphere that is within the dynamic range of most imaging instruments on Earth-orbiting spacecraft. The excellent photometric stability of the Lunar surface will allow its use as a long-term instrument calibration source once the dependence of Lunar spectral radiance on phase and libration angles are well characterized. A program to provide this characterization is underway. Observations are being made in 23 bands within 350-950 nm, 7 of which correspond closely with spacecraft instrument bands. Observations in nine bands within 950-2500 nm began recently. Although at this time the absolute Lunar radiance model is preliminary and uncertainties are larger than most instrument calibration goals, changes in spacecraft instrument sensitivity can be precisely monitored and absolute calibration can be applied retroactively as the accuracy of the Lunar spectral radiance model improves. Several space-based imaging systems have already begun using the Moon for calibration and the EOS AM-1 platform will make periodic attitude maneuvers for Lunar and space calibration.

Evaluating a fish monitoring protocol using state-space hierarchical models

USGS Publications Warehouse

Russell, Robin E.; Schmetterling, David A.; Guy, Chris S.; Shepard, Bradley B.; McFarland, Robert; Skaar, Donald

2012-01-01

Using data collected from three river reaches in Montana, we evaluated our ability to detect population trends and predict fish future fish abundance. Data were collected as part of a long-term monitoring program conducted by Montana Fish, Wildlife and Parks to primarily estimate rainbow (Oncorhynchus mykiss) and brown trout (Salmo trutta) abundance in numerous rivers across Montana. We used a hierarchical Bayesian mark-recapture model to estimate fish abundance over time in each of the three river reaches. We then fit a state-space Gompertz model to estimate current trends and future fish populations. Density dependent effects were detected in 1 of the 6 fish populations. Predictions of future fish populations displayed wide credible intervals. Our simulations indicated that given the observed variation in the abundance estimates, the probability of detecting a 30% decline in fish populations over a five-year period was less than 50%. We recommend a monitoring program that is closely tied to management objectives and reflects the precision necessary to make informed management decisions.

Constrained space camera assembly

DOEpatents

Heckendorn, F.M.; Anderson, E.K.; Robinson, C.W.; Haynes, H.B.

1999-05-11

A constrained space camera assembly which is intended to be lowered through a hole into a tank, a borehole or another cavity is disclosed. The assembly includes a generally cylindrical chamber comprising a head and a body and a wiring-carrying conduit extending from the chamber. Means are included in the chamber for rotating the body about the head without breaking an airtight seal formed therebetween. The assembly may be pressurized and accompanied with a pressure sensing means for sensing if a breach has occurred in the assembly. In one embodiment, two cameras, separated from their respective lenses, are installed on a mounting apparatus disposed in the chamber. The mounting apparatus includes means allowing both longitudinal and lateral movement of the cameras. Moving the cameras longitudinally focuses the cameras, and moving the cameras laterally away from one another effectively converges the cameras so that close objects can be viewed. The assembly further includes means for moving lenses of different magnification forward of the cameras. 17 figs.

Waste collection subsystem study

NASA Technical Reports Server (NTRS)

1984-01-01

Practical ways were explored of improving waste compaction and of providing rapid turnaround between flights at essentially no cost for the space shuttle waste collection subsystem commode. Because of the possible application of a fully developed shuttle commode to the space station, means of providing waste treatment without overboard venting were also considered. Three basic schemes for compaction and rapid turnaround, each fully capable of meeting the objectives, were explored in sufficient depth to bring out the characteristic advantages and disadvantages of each. Tradeoff comparisons were very close between leading contenders and efforts were made to refine the design concepts sufficiently to justify a selection. The concept selected makes use of a sealed canister containing wastes that have been forcibly compacted, which is removable in flight. No selection was made between three superior non-venting treatment methods owing to the need for experimental evaluations of the processes involved. A system requirements definition document has been prepared to define the task for a test embodiment of the selected concept.

The nucleus of 19/P Borrelly as revealed by deep space 1

USGS Publications Warehouse

Buratti, B.; Hicks, M.; Soderblom, L.; Britt, D.; Boice, D.; Brown, R.; Nelson, R.; Oberst, J.; Owen, Timothy W.; Sandel, B.; Stern, S.A.; Thomas, N.; Yelle, R.

2002-01-01

The Deep Space 1 encounter with comet 19/P Borrelly offered the first close-up view of a comet unobscured by dust. The geometric albedo of the comet is 0.029±0.006 (with a size of 8.0 × 3.15 km), comparable to the low-albedo hemisphere of Iapetus, the lowest albedo C-type asteroids, and the Uranian rings. Albedo variegations on the body are substantial, far greater than on the handful of asteroids so far scrutinized by spacecraft. The Bond albedo of Borrelly is 0.009 ± 0.002, the lowest of any object in the Solar System. The physical photometric parameters of the comet are similar to asteroids, but the optically active portion of its regolith may be fluffier. Differences in macroscopic roughness exist on its surface: the older regions appear to be slightly less rough, as if low-lying regions are infilled with native dust. Regional differences in the single particle phase function exist, with small regions exhibiting almost isotropic functions.

Pilot Non-Conformance to Alerting System Commands During Closely Spaced Parallel Approaches

NASA Technical Reports Server (NTRS)

Pritchett, Amy R.; Hansman, R. John

1997-01-01

Pilot non-conformance to alerting system commands has been noted in general and to a TCAS-like collision avoidance system in a previous experiment. This paper details two experiments studying collision avoidance during closely-spaced parallel approaches in instrument meteorological conditions (IMC), and specifically examining possible causal factors of, and design solutions to, pilot non-conformance.

KSC-03pd2762

NASA Image and Video Library

2003-10-01

KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, Ryan Levann, with United Space Alliance, checks data on the tile removed from the thermal barrier around the umbilical areas, the external tank attach points, on the underside of Atlantis. The umbilical areas are closed off after ET separation by a door, seen here. The exposed area of each closed door is covered with reusable surface insulation.

Decentralized control algorithms of a group of vehicles in 2D space

NASA Astrophysics Data System (ADS)

Pshikhopov, V. K.; Medvedev, M. Y.; Fedorenko, R. V.; Gurenko, B. V.

2017-02-01

The problem of decentralized control of group of robots, described by kinematic and dynamic equations of motion in the plane, is considered. Group performs predetermined rectangular area passing at a fixed speed, keeping the line and a uniform distribution. The environment may contain a priori unknown moving or stationary obstacles. Decentralized control algorithms, based on the formation of repellers in the state space of robots, are proposed. These repellers form repulsive forces generated by dynamic subsystems that extend the state space of robots. These repulsive forces are dynamic functions of distances and velocities of robots in the area of operation of the group. The process of formation of repellers allows to take into account the dynamic properties of robots, such as the maximum speed and acceleration. The robots local control law formulas are derived based on positionally-trajectory control method, which allows to operate with non-linear models. Lyapunov function in the form of a quadratic function of the state variables is constructed to obtain a nonlinear closed-loop control system. Due to the fact that a closed system is decomposed into two independent subsystems Lyapunov function is also constructed as two independent functions. Numerical simulation of the motion of a group of five robots is presented. In this simulation obstacles are presented by the boundaries of working area and a movable object of a given radius, moving rectilinear and uniform. Obstacle speed is comparable to the speeds of the robots in a group. The advantage of the proposed method is ensuring the stability of the trajectories and consideration of the limitations on the speed and acceleration at the trajectory planning stage. Proposed approach can be used for more general robots' models, including robots in the three-dimensional environment.

Nonwoven Fabric Uses and Prospects in Human Space Flight

NASA Technical Reports Server (NTRS)

Bacon, Jack

2001-01-01

The US space shuttle fleet has been flying for over 20 years. Although the shuttle operates in a unique exterior environment, the interior is intentionally made to be as close to the "normal" human environment as possible. The filtration needs of the shuttle are not substantially different from those of a large mobile home or camper, supporting the needs of a family of seven for up to two weeks. Therefore, most of the materials that are used to filter the air, water, and other fluids on the Shuttle are similar or identical to those employed in other sectors of the transportation industry. The only significantly different feature of the space environment is the unique "three-phase" nature of the air (with suspended liquids and solids ranging in size from aerosol droplets to binoculars). Such suspended debris contributes to the air filtration and waste management problem. Careful flow management and cleanliness practices help to mitigate the effect of debris, and liquid spills are rare, seldom making it to the filters. (It has been common on all spacecraft to look first for lost items on the air intake filters, since all objects ultimately migrate there in the flow. Liquids tend to seep rather than "spill", and so tend to aggregate in a ball near the source.) In addition to the basic fluids of the interior environment (water and water wastes, air, and its constituent supply gasses) the shuttle also has unfiltered fluid systems for Freon, hydrogen, helium, ammonia, hydraulic fluid, and propellants. Only the propellant system, owing to its uncommon chemistry, represents a fluid system that is not typical of household or medical applications. Careful external filtration prior to flight assures the cleanliness in these closed systems.

Autonomous Space Object Catalogue Construction and Upkeep Using Sensor Control Theory

NASA Astrophysics Data System (ADS)

Moretti, N.; Rutten, M.; Bessell, T.; Morreale, B.

The capability to track objects in space is critical to safeguard domestic and international space assets. Infrequent measurement opportunities, complex dynamics and partial observability of orbital state makes the tracking of resident space objects nontrivial. It is not uncommon for human operators to intervene with space tracking systems, particularly in scheduling sensors. This paper details the development of a system that maintains a catalogue of geostationary objects through dynamically tasking sensors in real time by managing the uncertainty of object states. As the number of objects in space grows the potential for collision grows exponentially. Being able to provide accurate assessment to operators regarding costly collision avoidance manoeuvres is paramount; the accuracy of which is highly dependent on how object states are estimated. The system represents object state and uncertainty using particles and utilises a particle filter for state estimation. Particle filters capture the model and measurement uncertainty accurately, allowing for a more comprehensive representation of the state’s probability density function. Additionally, the number of objects in space is growing disproportionally to the number of sensors used to track them. Maintaining precise positions for all objects places large loads on sensors, limiting the time available to search for new objects or track high priority objects. Rather than precisely track all objects our system manages the uncertainty in orbital state for each object independently. The uncertainty is allowed to grow and sensor data is only requested when the uncertainty must be reduced. For example when object uncertainties overlap leading to data association issues or if the uncertainty grows to beyond a field of view. These control laws are formulated into a cost function, which is optimised in real time to task sensors. By controlling an optical telescope the system has been able to construct and maintain a catalogue of approximately 100 geostationary objects.

Expandable pallet for space station interface attachments

NASA Technical Reports Server (NTRS)

Wesselski, Clarence J. (Inventor)

1988-01-01

Described is a foldable expandable pallet for Space Station interface attachments with a basic square configuration. Each pallet consists of a series of struts joined together by node point fittings to make a rigid structure. The struts have hinge fittings which are spring loaded to permit collapse of the module for stowage transport to a Space Station in the payload bay of the Space Shuttle, and development on orbit. Dimensions of the pallet are selected to provide convenient, closely spaced attachment points between the node points of the relatively widely spaced trusses of a Space Station platform. A pallet is attached to a strut at four points: one close fitting hole, two oversize holes, and a slot to allow for thermal expansion/contraction and for manufacturing tolerances. Applications of the pallet include its use in rotary or angular joints; servicing of splints; with gridded plates; as instrument mounting bases; and as a roadbed for a Mobile Service Center (MSC).

Alveolar ridge expansion-assisted orthodontic space closure in the mandibular posterior region.

PubMed

Ozer, Mete; Akdeniz, Berat Serdar; Sumer, Mahmut

2013-12-01

Orthodontic closure of old, edentulous spaces in the mandibular posterior region is a major challenge. In this report, we describe a method of orthodontic closure of edentulous spaces in the mandibular posterior region accelerated by piezoelectric decortication and alveolar ridge expansion. Combined piezosurgical and orthodontic treatments were used to close 14- and 15-mm-wide spaces in the mandibular left and right posterior areas, respectively, of a female patient, aged 18 years and 9 months, diagnosed with skeletal Class III malocclusion, hypodontia, and polydiastemas. After the piezoelectric decortication, segmental and full-arch mechanics were applied in the orthodontic phase. Despite some extent of root resorption and anchorage loss, the edentulous spaces were closed, and adequate function and esthetics were regained without further restorative treatment. Alveolar ridge expansion-assisted orthodontic space closure seems to be an effective and relatively less-invasive treatment alternative for edentulous spaces in the mandibular posterior region.

Alveolar ridge expansion-assisted orthodontic space closure in the mandibular posterior region

PubMed Central

Akdeniz, Berat Serdar; Sumer, Mahmut

2013-01-01

Orthodontic closure of old, edentulous spaces in the mandibular posterior region is a major challenge. In this report, we describe a method of orthodontic closure of edentulous spaces in the mandibular posterior region accelerated by piezoelectric decortication and alveolar ridge expansion. Combined piezosurgical and orthodontic treatments were used to close 14- and 15-mm-wide spaces in the mandibular left and right posterior areas, respectively, of a female patient, aged 18 years and 9 months, diagnosed with skeletal Class III malocclusion, hypodontia, and polydiastemas. After the piezoelectric decortication, segmental and full-arch mechanics were applied in the orthodontic phase. Despite some extent of root resorption and anchorage loss, the edentulous spaces were closed, and adequate function and esthetics were regained without further restorative treatment. Alveolar ridge expansion-assisted orthodontic space closure seems to be an effective and relatively less-invasive treatment alternative for edentulous spaces in the mandibular posterior region. PMID:24396740

ARC-1978-AC78-0330-4

NASA Image and Video Library

1978-04-18

Artist: Rick Guidice Space Colonization regenerative life support systems. This concept from a summer study done in 1977 depicts a closed loop life support system for long duration space settlements or space industrialization.

New mathematical modeling for a location-routing-inventory problem in a multi-period closed-loop supply chain in a car industry

NASA Astrophysics Data System (ADS)

Forouzanfar, F.; Tavakkoli-Moghaddam, R.; Bashiri, M.; Baboli, A.; Hadji Molana, S. M.

2017-11-01

This paper studies a location-routing-inventory problem in a multi-period closed-loop supply chain with multiple suppliers, producers, distribution centers, customers, collection centers, recovery, and recycling centers. In this supply chain, centers are multiple levels, a price increase factor is considered for operational costs at centers, inventory and shortage (including lost sales and backlog) are allowed at production centers, arrival time of vehicles of each plant to its dedicated distribution centers and also departure from them are considered, in such a way that the sum of system costs and the sum of maximum time at each level should be minimized. The aforementioned problem is formulated in the form of a bi-objective nonlinear integer programming model. Due to the NP-hard nature of the problem, two meta-heuristics, namely, non-dominated sorting genetic algorithm (NSGA-II) and multi-objective particle swarm optimization (MOPSO), are used in large sizes. In addition, a Taguchi method is used to set the parameters of these algorithms to enhance their performance. To evaluate the efficiency of the proposed algorithms, the results for small-sized problems are compared with the results of the ɛ-constraint method. Finally, four measuring metrics, namely, the number of Pareto solutions, mean ideal distance, spacing metric, and quality metric, are used to compare NSGA-II and MOPSO.

[Bio-objects and biological methods of space radiation effects evaluation].

PubMed

Kaminskaia, E V; Nevzgodina, L V; Platova, N G

2009-01-01

The unique conditions of space experiments place austere requirements to bio-objects and biological methods of radiation effects evaluation. The paper discusses suitability of a number of bio-objects varying in stage of evolution and metabolism for space researches aimed to state common patterns of the radiation damage caused by heavy ions (HI), and character of HI-cell interaction. Physical detectors in space experiments of the BIOBLOCK series make it possible to identify bio-objects hit by space HI and to set correlation between HI track topography and biological effect. The paper provides an all-round description of the bio-objects chosen for two BIOBLOCK experiments (population of hydrophyte Wolffia arrhiza (fam. duckweed) and Lactuca sativa seeds) and the method of evaluating effects from single space radiation HI. Direct effects of heavy ions on cells can be determined by the criteria of chromosomal aberrations and delayed morphologic abnormalities. The evaluation results are compared with the data about human blood lymphocytes. Consideration is being given to the procedures of test-objects' treatment and investigation.

Real-time posture reconstruction for Microsoft Kinect.

PubMed

Shum, Hubert P H; Ho, Edmond S L; Jiang, Yang; Takagi, Shu

2013-10-01

The recent advancement of motion recognition using Microsoft Kinect stimulates many new ideas in motion capture and virtual reality applications. Utilizing a pattern recognition algorithm, Kinect can determine the positions of different body parts from the user. However, due to the use of a single-depth camera, recognition accuracy drops significantly when the parts are occluded. This hugely limits the usability of applications that involve interaction with external objects, such as sport training or exercising systems. The problem becomes more critical when Kinect incorrectly perceives body parts. This is because applications have limited information about the recognition correctness, and using those parts to synthesize body postures would result in serious visual artifacts. In this paper, we propose a new method to reconstruct valid movement from incomplete and noisy postures captured by Kinect. We first design a set of measurements that objectively evaluates the degree of reliability on each tracked body part. By incorporating the reliability estimation into a motion database query during run time, we obtain a set of similar postures that are kinematically valid. These postures are used to construct a latent space, which is known as the natural posture space in our system, with local principle component analysis. We finally apply frame-based optimization in the space to synthesize a new posture that closely resembles the true user posture while satisfying kinematic constraints. Experimental results show that our method can significantly improve the quality of the recognized posture under severely occluded environments, such as a person exercising with a basketball or moving in a small room.

Gestalt grouping via closure degrades suprathreshold depth percepts.

PubMed

Deas, Lesley M; Wilcox, Laurie M

2014-08-19

It is well known that the perception of depth is susceptible to changes in configuration. For example, stereoscopic precision for a pair of vertical lines can be dramatically reduced when these lines are connected to form a closed object. Here, we extend this paradigm to suprathreshold estimates of perceived depth. Using a touch-sensor, observers made quantitative estimates of depth between a vertical line pair presented in isolation or as edges of a closed rectangular object with different figural interpretations. First, we show that the amount of depth estimated within a closed rectangular object is consistently reduced relative to the vertical edges presented in isolation or when they form the edges of two segmented objects. We then demonstrate that the reduction in perceived depth for closed objects is modulated by manipulations that influence perceived closure of the central figure. Depth percepts were most disrupted when the horizontal connectors and vertical lines matched in color. Perceived depth increased slightly when the connectors had opposite contrast polarity, but increased dramatically when flankers were added. Thus, as grouping cues were added to counter the interpretation of a closed object, the depth degradation effect was systematically eliminated. The configurations tested here rule out explanations based on early, local interactions such as inhibition or cue conflict; instead, our results provide strong evidence of the impact of Gestalt grouping, via closure, on depth magnitude percepts from stereopsis. © 2014 ARVO.

Rotor bore and turbine rotor wheel/spacer heat exchange flow circuit

DOEpatents

Caruso, Philip M.; Eldrid, Sacheverel Quentin; Ladhani, Azad A.; DeMania, Alan Richard; Palmer, Gene David; Wilson, Ian David; Rathbun, Lisa Shirley; Akin, Robert Craig

2002-01-01

In a turbine having closed-circuit steam-cooling passages about the rim of the rotor during steady-state operation, compressor discharge air is supplied to the rotor bore for passage radially outwardly into the wheel space cavities between the wheels and spacers. Communicating slots and channels in the spacers and wheels at circumferentially spaced positions enable egress of the compressor discharge air into the hot gas flow path. At turbine startup, cooling air flows through the closed-circuit steam passages to cool the outer rim of the rotor while compressor discharge air pre-warms the wheels and spacers. At steady-state, cooling steam is supplied in the closed-circuit steam-cooling passages and compressor discharge air is supplied through the bore and into the wheel space cavities to cool the rotor.

Welcome to Outer Space

NASA Technical Reports Server (NTRS)

1999-01-01

This video gives a brief history of the Jet Propulsion Laboratory, current missions and what the future may hold. Scenes includes various planets in the solar system, robotic exploration of space, discussions on the Hubble Space Telescope, the source of life, and solar winds. This video was narrated by Jodie Foster. Animations include: close-up image of the Moon; close-up images of the surface of Mars; robotic exploration of Mars; the first mapping assignment of Mars; animated views of Jupiter; animated views of Saturn; and views of a Giant Storm on Neptune called the Great Dark Spot.

Closed Loop System Identification with Genetic Algorithms

NASA Technical Reports Server (NTRS)

Whorton, Mark S.

2004-01-01

High performance control design for a flexible space structure is challenging since high fidelity plant models are di.cult to obtain a priori. Uncertainty in the control design models typically require a very robust, low performance control design which must be tuned on-orbit to achieve the required performance. Closed loop system identi.cation is often required to obtain a multivariable open loop plant model based on closed-loop response data. In order to provide an accurate initial plant model to guarantee convergence for standard local optimization methods, this paper presents a global parameter optimization method using genetic algorithms. A minimal representation of the state space dynamics is employed to mitigate the non-uniqueness and over-parameterization of general state space realizations. This control-relevant system identi.cation procedure stresses the joint nature of the system identi.cation and control design problem by seeking to obtain a model that minimizes the di.erence between the predicted and actual closed-loop performance.

Space ecosynthesis: An approach to the design of closed ecosystems for use in space

NASA Technical Reports Server (NTRS)

Macelroy, R. D.; Averner, M. M.

1978-01-01

The use of closed ecological systems for the regeneration of wastes, air, and water is discussed. It is concluded that such systems, if they are to be used for the support of humans in space, will require extensive mechanical and physico-chemical support. The reason for this is that the buffering capacity available in small systems is inadequate, and that natural biological and physical regulatory mechanisms rapidly become inoperative. It is proposed that mathematical models of the dynamics of a closed ecological system may provide the best means of studying the initial problems of ecosystem closure. A conceptual and mathematical model of a closed ecosystem is described which treats the biological components as a farm, calculates the rates of flow of elements through the system by mass-balance techniques and control theory postulates, and can evaluate the requirements for mechanical buffering activities. It is suggested that study of the closure of ecosystems can significantly aid in the establishment of general principles of ecological systems.

Heuristic approach to image registration

NASA Astrophysics Data System (ADS)

Gertner, Izidor; Maslov, Igor V.

2000-08-01

Image registration, i.e. correct mapping of images obtained from different sensor readings onto common reference frame, is a critical part of multi-sensor ATR/AOR systems based on readings from different types of sensors. In order to fuse two different sensor readings of the same object, the readings have to be put into a common coordinate system. This task can be formulated as optimization problem in a space of all possible affine transformations of an image. In this paper, a combination of heuristic methods is explored to register gray- scale images. The modification of Genetic Algorithm is used as the first step in global search for optimal transformation. It covers the entire search space with (randomly or heuristically) scattered probe points and helps significantly reduce the search space to a subspace of potentially most successful transformations. Due to its discrete character, however, Genetic Algorithm in general can not converge while coming close to the optimum. Its termination point can be specified either as some predefined number of generations or as achievement of a certain acceptable convergence level. To refine the search, potential optimal subspaces are searched using more delicate and efficient for local search Taboo and Simulated Annealing methods.

Hypervelocity Dust Impacts in Space and the Laboratory

NASA Astrophysics Data System (ADS)

Horanyi, Mihaly; Colorado CenterLunar Dust; Atmospheric Studies (CCLDAS) Team

2013-10-01

Interplanetary dust particles continually bombard all objects in the solar system, leading to the excavation of material from the target surfaces, the production of secondary ejecta particles, plasma, neutral gas, and electromagnetic radiation. These processes are of interest to basic plasma science, planetary and space physics, and engineering to protect humans and instruments against impact damages. The Colorado Center for Lunar Dust and Atmospheric Studies (CCLDAS) has recently completed a 3 MV dust accelerator, and this talk will summarize our initial science results. The 3 MV Pelletron contains a dust source, feeding positively charged micron and sub-micron sized particles into the accelerator. We will present the technical details of the facility and its capabilities, as well as the results of our initial experiments for damage assessment of optical devices, and penetration studies of thin films. We will also report on the completion of our dust impact detector, the Lunar Dust Experiment (LDEX), is expected to be flying onboard the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission by the time of this presentation. LDEX was tested, and calibrated at our dust accelerator. We will close by offering the opportunity to use this facility by the planetary, space and plasma physics communities.

Simulation of the Processes of Formation of a Dust Cloud in a Vacuum and in the Absence of Gravitation

NASA Astrophysics Data System (ADS)

Avdeev, A. V.; Boreisho, A. S.; Ivakin, S. V.; Moiseev, A. A.; Savin, A. V.; Sokolov, E. I.; Smirnov, P. G.

2018-01-01

This article is devoted to the simulation of the processes of formation of dust clouds in the absence of gravitation, which is necessary for understanding the processes proceeding in dust clusters in outer space, upper planetary atmosphere, and on the surface of space objects, as well as for evaluating the possibilities of creating disperse structures with given properties. The chief aim of the simulation is to determine the general laws of the dynamics of the dust cloud at the initial stage of its formation. With the use of the original approach based on the particle-in-cell method that permits investigating the mechanics of large ensembles of particles on contemporary computational platforms, we consider the mechanics of a dusty medium in the process of its excitation in a closed container due to the vibration of the walls, and then in the process of particle scattering when the container opens in outer space. The main formation mechanisms of a dust formation have been elucidated, and the possibilities of mathematical simulation for predicting spatial and time characteristics of disperse structures have been shown.

Search-based model identification of smart-structure damage

NASA Technical Reports Server (NTRS)

Glass, B. J.; Macalou, A.

1991-01-01

This paper describes the use of a combined model and parameter identification approach, based on modal analysis and artificial intelligence (AI) techniques, for identifying damage or flaws in a rotating truss structure incorporating embedded piezoceramic sensors. This smart structure example is representative of a class of structures commonly found in aerospace systems and next generation space structures. Artificial intelligence techniques of classification, heuristic search, and an object-oriented knowledge base are used in an AI-based model identification approach. A finite model space is classified into a search tree, over which a variant of best-first search is used to identify the model whose stored response most closely matches that of the input. Newly-encountered models can be incorporated into the model space. This adaptativeness demonstrates the potential for learning control. Following this output-error model identification, numerical parameter identification is used to further refine the identified model. Given the rotating truss example in this paper, noisy data corresponding to various damage configurations are input to both this approach and a conventional parameter identification method. The combination of the AI-based model identification with parameter identification is shown to lead to smaller parameter corrections than required by the use of parameter identification alone.

STS-103 Mission Highlights Resource Tape (1 of 2)

NASA Technical Reports Server (NTRS)

2000-01-01

The STS-103 flight crew, Commander Curtis L. Brown, Pilot Scott J. Kelly, Mission Specialists Steven L. Smith, C. Michael Foale, John M. Grunsfeld, Claude Nicollier, and Jean-Francois Clervoy, are seen performing pre-launch activities such as crew suit-up, and ride out to the launch pad for a night launch. Also, included are various panoramic views of the shuttle on the pad. The crew is readied in the White Room for their mission. After the closing of the hatch and arm retraction, launch activities are shown including countdown, engine ignition, launch, and the separation of the Solid Rocket Boosters. Once on-orbit the primary objective is to capture and service the Hubble Space Telescope. Included are various live shots of the payload bay showing the flight support system, the orbiter replacement unit carrier and the forward fixture that house the new Fine Guidance System (FGS). Smith and Grunsfeld replaces and changes the sensor units during the first space walk of this mission. The second space walk by Nicollier and Foale includes the changing of the computer and installation of the FGS. This is tape 1 of 2, tape 2 has a report number of NONP-NASA-VT-2000036031.

National Space Transportation Systems Program mission report

NASA Technical Reports Server (NTRS)

Collins, M. A., Jr.; Aldrich, A. D.; Lunney, G. S.

1984-01-01

The 515-41B National Space Transportation Systems Program Mission Report contains a summary of the major activities and accomplishments of the sixth operational Shuttle flight and fourth flight of the OV-099 vehicle, Challenger. Since this flight was the first to land at Kennedy Space Center, the vehicle was towed directly to the OPF (Orbiter Processing Facility) where preparations for flight STS-41C, scheduled for early April 1984, began immediately. The significant problems that occurred during STS-41B are summarized and a problem tracking list that is a complete list of all problems that occurred during the flight is given. None of the problems will affect the STS 41C flight. The major objectives of flight STS-41B were to successfully deploy the Westar satellite and the Indonesian Communications Satellite-B2 (PALAPA-B2); to evaluate the MMU (Manned Maneuvering Unit) support for EVA (Extravehicular Activities); to exercise the MFR (Manipulator Foot Restraint); to demonstrate a closed loop rendezvous; and to operate the M.R (Monodisperse Latex Reactor), the ACES (Acoustic Containerless Experiment System) and the IEF (Isoelectric Focusing) in cabin experiments; and to obtain photographs with the Cinema 360 Cameras.

Updated Heliostorm Warning Mission: Enhancements Based on New Technology

NASA Technical Reports Server (NTRS)

Young, Roy M.

2010-01-01

The Heliostorm (also referred to as Geostorm) mission has been regarded as the best choice for the first application of solar sail technology. The objective of Heliostorm is to obtain data from an orbit station slightly displaced from the ecliptic at or nearer to the Sun than 0.98 AU, which places it twice as close to the sun as Earth's natural L1 point at 0.993 AU. Heliostorm has been the subject of several mission studies over the past decade, with the most complete study conducted in 1999 in conjunction with a proposed New Millennium Program (NMP) Space Technology 5 (ST-5) flight opportunity. Recently, over a two and one-half year period dating from 2002 through 2005, NASA s In-Space Propulsion Technology Program (ISTP) matured solar sail technology from laboratory components to fully integrated systems, demonstrated in as relevant a space environment as could feasibly be simulated on the ground. Work under this program has yielded promising results for enhanced Heliostorm mission performance. This paper will present the preliminary results of an updated Heliostorm mission design study including the enhancements incorporated during the design, development, analysis and testing of the system ground demonstrator.

The Atsa Suborbital Observatory: An Observatory for a Commercial Suborbital Spacecraft

NASA Astrophysics Data System (ADS)

Vilas, F.; Sollitt, L. S.

2012-12-01

The advantages of astronomical observations made above Earth's atmosphere have long been understood: free access to spectral regions inaccessible from Earth (e.g., UV) or affected by the atmosphere's content (e.g., IR). Most robotic, space-based telescopes maintain large angular separation between the Sun and an observational target in order to avoid accidental damage to instruments from the Sun. For most astronomical targets, this possibility is easily avoided by waiting until objects are visible away from the Sun. For the Solar System objects inside Earth's orbit, this is never the case. Suborbital astronomical observations have over 50 years' history using NASA's sounding rockets and experimental space planes. Commercial suborbital spacecraft are largely expected to go to ~100 km altitude above Earth, providing a limited amount of time for astronomical observations. The unique scientific advantage to these observations is the ability to point close to the Sun: if a suborbital spacecraft accidentally turns too close to the Sun and fries an instrument, it is easy to land the spacecraft and repair the hardware for the next flight. Objects uniquely observed during the short observing window include inner-Earth asteroids, Mercury, Venus, and Sun-grazing comets. Both open-FOV and target-specific observations are possible. Despite many space probes to the inner Solar System, scientific questions remain. These include inner-Earth asteroid size and bulk density informing Solar System evolution studies and efforts to develop methods of mitigation against imminent impactors to Earth; chemistry and dynamics of Venus' atmosphere addressing physical phenomena such as greenhouse effect, atmospheric super-rotation and global resurfacing on Venus. With the Atsa Suborbital Observatory, we combine the strengths of both ground-based observatories and space-based observing to create a facility where a telescope is maintained and used interchangeably with both in-house facility instruments or user-provided instruments. Rapid turnaround will depend only on flight frequency. Data are stored on-board for retrieval when the spacecraft lands. We provide robust instrumentation that can survive suborbital spaceflight, assessment of the feasibility of the requested observations, rigorous scripting of the telescope operation, integration of the telescope plus instrument in a provider spacecraft, and periodic preventive maintenance for the telescope and instrument suite. XCOR Aerospace's Lynx III spacecraft is the best candidate vehicle to host a suborbital astronomical observatory. Unlike other similar vehicles, the Lynx will operate with only 1 or 2 people onboard (the pilot and an operator), allowing for each mission to be totally dedicated to the observation (no tourists will be bumping about; no other experiments will affect spacecraft pointing). A stable platform, the Lynx can point to an accuracy of ± 0.5o. Fine pointing is done by the telescope system. Best of all, the Lynx has a dorsal pod that opens directly to space. For astronomical observations, the best window is NO window. Currently, we plan to deploy a 20" diameter telescope in the Lynx III dorsal pod. XCOR Aerospace has the goal of eventually maintaining a Lynx flight frequency capability of 4 times/day. As with any observatory, Atsa will be available for observations by the community at large.

Vacuum force

NASA Astrophysics Data System (ADS)

Han, Yongquan

2015-03-01

To study on vacuum force, we must clear what is vacuum, vacuum is a space do not have any air and also ray. There is not exist an absolute the vacuum of space. The vacuum of space is relative, so that the vacuum force is relative. There is a certain that vacuum vacuum space exists. In fact, the vacuum space is relative, if the two spaces compared to the existence of relative vacuum, there must exist a vacuum force, and the direction of the vacuum force point to the vacuum region. Any object rotates and radiates. Rotate bend radiate- centripetal, gravity produced, relative gravity; non gravity is the vacuum force. Gravity is centripetal, is a trend that the objects who attracted wants to Centripetal, or have been do Centripetal movement. Any object moves, so gravity makes the object curve movement, that is to say, the radiation range curve movement must be in the gravitational objects, gravity must be existed in non vacuum region, and make the object who is in the region of do curve movement (for example: The earth moves around the sun), or final attracted in the form gravitational objects, and keep relatively static with attract object. (for example: objects on the earth moves but can't reach the first cosmic speed).

Sibling cycle piston and valving method

NASA Technical Reports Server (NTRS)

Mitchell, Matthew P. (Inventor); Bauwens, Luc (Inventor)

1990-01-01

A double-acting, rotating piston reciprocating in a cylinder with the motion of the piston providing the valving action of the Sibling Cycle through the medium of passages between the piston and cylinder wall. The rotating piston contains regenerators ported to the walls of the piston. The piston fits closely in the cylinder at each end of the cylinder except in areas where the wall of the cylinder is relieved to provide passages between the cylinder wall and the piston leading to the expansion and compression spaces, respectively. The piston reciprocates as it rotates. The cylinder and piston together comprise an integral valve that seqentially opens and closes the ports at the ends of the regenerators alternately allowing them to communicate with the expansion space and compression space and blocking that communication. The relieved passages in the cylinder and the ports in the piston are so arranged that each regenerator is sequentially (1) charged with compressed working gas from the compression space; (2) isolated from both expansion and compression spaces; (3) discharged of working gas into the expansion space; and (4) simultaneously charged with working gas from the expansion space while being discharged of working gas into the compression space, in the manner of the Sibling Cycle. In an alterate embodiment, heat exchangers are external to the cylinder and ports in the cylinder wall are alternately closed by the wall of the piston and opened to the expansion and compression spaces through relieved passages in the wall of the reciprocating, rotating piston.

Comparing long-term projections of the space debris environment to real world data - Looking back to 1990

NASA Astrophysics Data System (ADS)

Radtke, Jonas; Stoll, Enrico

2016-10-01

Long-term projections of the space debris environment are commonly used to assess the trends within different scenarios for the assumed future development of spacefaring. General scenarios investigated include business-as-usual cases in which spaceflight is performed as today and mitigation scenarios, assuming the implementation of Space Debris Mitigation Guidelines at different advances or the effectiveness of more drastic measures, such as active debris removal. One problem that always goes along with the projection of a system's behaviour in the future is that affecting parameters, such as the launch rate, are unpredictable. It is common to look backwards and re-model the past in other fields of research. This is a rather difficult task for spaceflight as it is still quite young, and furthermore mostly influenced by drastic politic changes, as the break-down of the Soviet Union in the end of the 1980s. Furthermore, one major driver of the evolution of the number of on-orbit objects turn out to be collisions between objects. As of today, these collisions are, fortunately, very rare and therefore, a real-world-data modelling approach is difficult. Nevertheless, since the end of the cold war more than 20 years of a comparably stable evolution of spaceflight activities have passed. For this study, this period is used in a comparison between the real evolution of the space debris environment and that one projected using the Institute of Space System's in-house tool for long-term assessment LUCA (Long-Term Utility for Collision Analysis). Four different scenarios are investigated in this comparison; all of them have the common starting point of using an initial population for 1st May 1989. The first scenario, which serves as reference, is simply taken from MASTER-2009. All launch and mission related objects from the Two Line Elements (TLE) catalogue and other available sources are included. All events such as explosion and collision events have been re-modelled as close to the reality as possible and included in the corresponding population. They furthermore have been correlated with TLE catalogue objects. As the latest available validated population snapshot for MASTER is May 2009, this epoch is chosen as endpoint for the simulations. The second scenario uses the knowledge of the past 25 years to perform a Monte-Carlo simulation of the evolution of the space debris environment. Necessary input parameters such as explosions per year, launch rates, and the evolution of the solar cycle are taken from their real evolutions. The third scenario goes a step further by only extracting mean numbers and trends from inputs such as launch and explosion rates and applying them. The final and fourth scenario aims to disregarding all knowledge of the time frame under investigation and inputs are determined based on data available in 1989 only. Results are compared to the reference scenario of the space debris environment.

An enhanced multi-view vertical line locus matching algorithm of object space ground primitives based on positioning consistency for aerial and space images

NASA Astrophysics Data System (ADS)

Zhang, Ka; Sheng, Yehua; Wang, Meizhen; Fu, Suxia

2018-05-01

The traditional multi-view vertical line locus (TMVLL) matching method is an object-space-based method that is commonly used to directly acquire spatial 3D coordinates of ground objects in photogrammetry. However, the TMVLL method can only obtain one elevation and lacks an accurate means of validating the matching results. In this paper, we propose an enhanced multi-view vertical line locus (EMVLL) matching algorithm based on positioning consistency for aerial or space images. The algorithm involves three components: confirming candidate pixels of the ground primitive in the base image, multi-view image matching based on the object space constraints for all candidate pixels, and validating the consistency of the object space coordinates with the multi-view matching result. The proposed algorithm was tested using actual aerial images and space images. Experimental results show that the EMVLL method successfully solves the problems associated with the TMVLL method, and has greater reliability, accuracy and computing efficiency.

Near or far: The effect of spatial distance and vocabulary knowledge on word learning.

PubMed

Axelsson, Emma L; Perry, Lynn K; Scott, Emilly J; Horst, Jessica S

2016-01-01

The current study investigated the role of spatial distance in word learning. Two-year-old children saw three novel objects named while the objects were either in close proximity to each other or spatially separated. Children were then tested on their retention for the name-object associations. Keeping the objects spatially separated from each other during naming was associated with increased retention for children with larger vocabularies. Children with a lower vocabulary size demonstrated better retention if they saw objects in close proximity to each other during naming. This demonstrates that keeping a clear view of objects during naming improves word learning for children who have already learned many words, but keeping objects within close proximal range is better for children at earlier stages of vocabulary acquisition. The effect of distance is therefore not equal across varying vocabulary sizes. The influences of visual crowding, cognitive load, and vocabulary size on word learning are discussed. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perna, D.; Barucci, M. A.; Fornasier, S.

Through their delivery of water and organics, near-Earth objects (NEOs) played an important role in the emergence of life on our planet.  However, they also pose a hazard to the Earth, as asteroid impacts could significantly affect our civilization. Potentially hazardous asteroids (PHAs) are those that, in principle, could possibly impact the Earth within the next century, producing major damage. About 1600 PHAs are currently known, from an estimated population of 4700 ± 1450. However, a comprehensive characterization of the PHA physical properties is still missing. Here we present spectroscopic observations of 14 PHAs, which we have used to derive their taxonomy,more » meteorite analogs, and mineralogy. Combining our results with the literature, we investigated how PHAs are distributed as a function of their dynamical and physical properties. In general, the “carbonaceous” PHAs seem to be particularly threatening, because of their high porosity (limiting the effectiveness of the main deflection techniques that could be used in space) and low inclination and minimum orbit intersection distance (MOID) with the Earth (favoring more frequent close approaches). V-type PHAs also present low MOID values, which can produce frequent close approaches (as confirmed by the recent discovery of a limited space weathering on their surfaces). We also identified those specific objects that deserve particular attention because of their extreme rotational properties, internal strength, or possible cometary nature. For PHAs and NEOs in general, we identified a possible anti-correlation between the elongation and the rotational period, in the range of P{sub rot} ≈ 5–80 hr. This would be compatible with the behavior of gravity-dominated aggregates in rotational equilibrium. For periods ≳80–90 hr, such a trend stops, possibly under the influence of the YORP effect and collisions. However, the statistics is very low, and further observational and theoretical work is required to characterize such slow rotators.« less

CAPS Simulation Environment Development

NASA Technical Reports Server (NTRS)

Murphy, Douglas G.; Hoffman, James A.

2005-01-01

The final design for an effective Comet/Asteroid Protection System (CAPS) will likely come after a number of competing designs have been simulated and evaluated. Because of the large number of design parameters involved in a system capable of detecting an object, accurately determining its orbit, and diverting the impact threat, a comprehensive simulation environment will be an extremely valuable tool for the CAPS designers. A successful simulation/design tool will aid the user in identifying the critical parameters in the system and eventually allow for automatic optimization of the design once the relationships of the key parameters are understood. A CAPS configuration will consist of space-based detectors whose purpose is to scan the celestial sphere in search of objects likely to make a close approach to Earth and to determine with the greatest possible accuracy the orbits of those objects. Other components of a CAPS configuration may include systems for modifying the orbits of approaching objects, either for the purpose of preventing a collision or for positioning the object into an orbit where it can be studied or used as a mineral resource. The Synergistic Engineering Environment (SEE) is a space-systems design, evaluation, and visualization software tool being leveraged to simulate these aspects of the CAPS study. The long-term goal of the SEE is to provide capabilities to allow the user to build and compare various CAPS designs by running end-to-end simulations that encompass the scanning phase, the orbit determination phase, and the orbit modification phase of a given scenario. Herein, a brief description of the expected simulation phases is provided, the current status and available features of the SEE software system is reported, and examples are shown of how the system is used to build and evaluate a CAPS detection design. Conclusions and the roadmap for future development of the SEE are also presented.

Colombia an approach to create a national space agency

NASA Astrophysics Data System (ADS)

Arenales, O.

Space exploration is a great human adventure: culturally, scientifically, technologically and industrially. Since the earliest of times, civilizations have been united in their awe of, and inspiration by, the cosmos, as testified in particularly by the peoples and cultures of the Central and South American continent in pre- Columbian times. Today, space systems have become an essential tool for the scientific disciplines related to the knowledge of the universe, including our own planet and its close or its remote environment. The main objective of this research is to explain the way in which Colombia, rich in myths and secular legends connecting mankind to the universe, must in the present tackle the issue of its development of space activities. The context in which it could be carried out is also described, along with a perspective of the current state of science and technology in the space sector on a global scale. Any modern nation is concerned with its independence, whether political, economic, or intellectual. That is why we support the concept of countries in the process of development becoming actively involved in the international space scene. Indeed, having limitations in industrial and technological exchange, we feel excluded today from key fields for our tomorrow. This paper thus proposes to demonstrate how in a time that can be regarded as one of the most serious crises in its history, Colombia could, in an atmosphere free from fratricidal conflicts, exploit its space matter capabilities. We do not limit our focus to the scientific field, but also consider the social, economic and cultural aspects. The results of this research delineate how Colombia could start a new optimistic phas e of its development, joining the international space programs within the framework of agreements among the regional governments in Latin America.

Polarimetric image reconstruction algorithms

NASA Astrophysics Data System (ADS)

Valenzuela, John R.

In the field of imaging polarimetry Stokes parameters are sought and must be inferred from noisy and blurred intensity measurements. Using a penalized-likelihood estimation framework we investigate reconstruction quality when estimating intensity images and then transforming to Stokes parameters (traditional estimator), and when estimating Stokes parameters directly (Stokes estimator). We define our cost function for reconstruction by a weighted least squares data fit term and a regularization penalty. It is shown that under quadratic regularization, the traditional and Stokes estimators can be made equal by appropriate choice of regularization parameters. It is empirically shown that, when using edge preserving regularization, estimating the Stokes parameters directly leads to lower RMS error in reconstruction. Also, the addition of a cross channel regularization term further lowers the RMS error for both methods especially in the case of low SNR. The technique of phase diversity has been used in traditional incoherent imaging systems to jointly estimate an object and optical system aberrations. We extend the technique of phase diversity to polarimetric imaging systems. Specifically, we describe penalized-likelihood methods for jointly estimating Stokes images and optical system aberrations from measurements that contain phase diversity. Jointly estimating Stokes images and optical system aberrations involves a large parameter space. A closed-form expression for the estimate of the Stokes images in terms of the aberration parameters is derived and used in a formulation that reduces the dimensionality of the search space to the number of aberration parameters only. We compare the performance of the joint estimator under both quadratic and edge-preserving regularization. The joint estimator with edge-preserving regularization yields higher fidelity polarization estimates than with quadratic regularization. Under quadratic regularization, using the reduced-parameter search strategy, accurate aberration estimates can be obtained without recourse to regularization "tuning". Phase-diverse wavefront sensing is emerging as a viable candidate wavefront sensor for adaptive-optics systems. In a quadratically penalized weighted least squares estimation framework a closed form expression for the object being imaged in terms of the aberrations in the system is available. This expression offers a dramatic reduction of the dimensionality of the estimation problem and thus is of great interest for practical applications. We have derived an expression for an approximate joint covariance matrix for object and aberrations in the phase diversity context. Our expression for the approximate joint covariance is compared with the "known-object" Cramer-Rao lower bound that is typically used for system parameter optimization. Estimates of the optimal amount of defocus in a phase-diverse wavefront sensor derived from the joint-covariance matrix, the known-object Cramer-Rao bound, and Monte Carlo simulations are compared for an extended scene and a point object. It is found that our variance approximation, that incorporates the uncertainty of the object, leads to an improvement in predicting the optimal amount of defocus to use in a phase-diverse wavefront sensor.

Behind the Photos and the Tears: Media Images, Neoliberal Discourses, Racialized Constructions of Space and School Closings in Chicago

ERIC Educational Resources Information Center

Allweiss, Alexandra; Grant, Carl A.; Manning, Karla

2015-01-01

This critical article provides insights into how media frames influence our understandings of school reform in urban spaces by examining images of students during the 2013 school closings in Chicago. Using visual framing analysis and informed by framing theory and critiques of neoliberalism we seek to explore two questions: (1) What role do media…

Optimization of a Thermodynamic Model Using a Dakota Toolbox Interface

NASA Astrophysics Data System (ADS)

Cyrus, J.; Jafarov, E. E.; Schaefer, K. M.; Wang, K.; Clow, G. D.; Piper, M.; Overeem, I.

2016-12-01

Scientific modeling of the Earth physical processes is an important driver of modern science. The behavior of these scientific models is governed by a set of input parameters. It is crucial to choose accurate input parameters that will also preserve the corresponding physics being simulated in the model. In order to effectively simulate real world processes the models output data must be close to the observed measurements. To achieve this optimal simulation, input parameters are tuned until we have minimized the objective function, which is the error between the simulation model outputs and the observed measurements. We developed an auxiliary package, which serves as a python interface between the user and DAKOTA. The package makes it easy for the user to conduct parameter space explorations, parameter optimizations, as well as sensitivity analysis while tracking and storing results in a database. The ability to perform these analyses via a Python library also allows the users to combine analysis techniques, for example finding an approximate equilibrium with optimization then immediately explore the space around it. We used the interface to calibrate input parameters for the heat flow model, which is commonly used in permafrost science. We performed optimization on the first three layers of the permafrost model, each with two thermal conductivity coefficients input parameters. Results of parameter space explorations indicate that the objective function not always has a unique minimal value. We found that gradient-based optimization works the best for the objective functions with one minimum. Otherwise, we employ more advanced Dakota methods such as genetic optimization and mesh based convergence in order to find the optimal input parameters. We were able to recover 6 initially unknown thermal conductivity parameters within 2% accuracy of their known values. Our initial tests indicate that the developed interface for the Dakota toolbox could be used to perform analysis and optimization on a `black box' scientific model more efficiently than using just Dakota.

Spatial Acuity and Prey Detection in Weakly Electric Fish

PubMed Central

Babineau, David; Lewis, John E; Longtin, André

2007-01-01

It is well-known that weakly electric fish can exhibit extreme temporal acuity at the behavioral level, discriminating time intervals in the submicrosecond range. However, relatively little is known about the spatial acuity of the electrosense. Here we use a recently developed model of the electric field generated by Apteronotus leptorhynchus to study spatial acuity and small signal extraction. We show that the quality of sensory information available on the lateral body surface is highest for objects close to the fish's midbody, suggesting that spatial acuity should be highest at this location. Overall, however, this information is relatively blurry and the electrosense exhibits relatively poor acuity. Despite this apparent limitation, weakly electric fish are able to extract the minute signals generated by small prey, even in the presence of large background signals. In fact, we show that the fish's poor spatial acuity may actually enhance prey detection under some conditions. This occurs because the electric image produced by a spatially dense background is relatively “blurred” or spatially uniform. Hence, the small spatially localized prey signal “pops out” when fish motion is simulated. This shows explicitly how the back-and-forth swimming, characteristic of these fish, can be used to generate motion cues that, as in other animals, assist in the extraction of sensory information when signal-to-noise ratios are low. Our study also reveals the importance of the structure of complex electrosensory backgrounds. Whereas large-object spacing is favorable for discriminating the individual elements of a scene, small spacing can increase the fish's ability to resolve a single target object against this background. PMID:17335346

Probability Forecasting Using Monte Carlo Simulation

NASA Astrophysics Data System (ADS)

Duncan, M.; Frisbee, J.; Wysack, J.

2014-09-01

Space Situational Awareness (SSA) is defined as the knowledge and characterization of all aspects of space. SSA is now a fundamental and critical component of space operations. Increased dependence on our space assets has in turn lead to a greater need for accurate, near real-time knowledge of all space activities. With the growth of the orbital debris population, satellite operators are performing collision avoidance maneuvers more frequently. Frequent maneuver execution expends fuel and reduces the operational lifetime of the spacecraft. Thus the need for new, more sophisticated collision threat characterization methods must be implemented. The collision probability metric is used operationally to quantify the collision risk. The collision probability is typically calculated days into the future, so that high risk and potential high risk conjunction events are identified early enough to develop an appropriate course of action. As the time horizon to the conjunction event is reduced, the collision probability changes. A significant change in the collision probability will change the satellite mission stakeholder's course of action. So constructing a method for estimating how the collision probability will evolve improves operations by providing satellite operators with a new piece of information, namely an estimate or 'forecast' of how the risk will change as time to the event is reduced. Collision probability forecasting is a predictive process where the future risk of a conjunction event is estimated. The method utilizes a Monte Carlo simulation that produces a likelihood distribution for a given collision threshold. Using known state and state uncertainty information, the simulation generates a set possible trajectories for a given space object pair. Each new trajectory produces a unique event geometry at the time of close approach. Given state uncertainty information for both objects, a collision probability value can be computed for every trail. This yields a collision probability distribution given known, predicted uncertainty. This paper presents the details of the collision probability forecasting method. We examine various conjunction event scenarios and numerically demonstrate the utility of this approach in typical event scenarios. We explore the utility of a probability-based track scenario simulation that models expected tracking data frequency as the tasking levels are increased. The resulting orbital uncertainty is subsequently used in the forecasting algorithm.

Space program: Space debris a potential threat to Space Station and shuttle

NASA Technical Reports Server (NTRS)

Schwartz, Stephen A.; Beers, Ronald W.; Phillips, Colleen M.; Ramos, Yvette

1990-01-01

Experts estimate that more than 3.5 million man-made objects are orbiting the earth. These objects - space debris - include whole and fragmentary parts of rocket bodies and other discarded equipment from space missions. About 24,500 of these objects are 1 centimeter across or larger. A 1-centimeter man-made object travels in orbit at roughly 22,000 miles per hour. If it hit a spacecraft, it would do about the same damage as would a 400-pound safe traveling at 60 miles per hour. The Government Accounting Office (GAO) reviews NASA's plans for protecting the space station from debris, the extent and precision of current NASA and Defense Department (DOD) debris-tracking capabilities, and the extent to which debris has already affected shuttle operations. GAO recommends that the space debris model be updated, and that the findings be incorporated into the plans for protecting the space station from such debris. GAO further recommends that the increased risk from debris to the space shuttle operations be analyzed.

Characterization of On-Orbit U.S. Lab Condensate Vacuum Venting

NASA Astrophysics Data System (ADS)

Schmidl, W. D.; Alred, J. A.; Mikatarian, R.; Soares, C.; Miles, E.

2002-01-01

The venting of liquid streams into a vacuum has been studied extensively for many years. An experiment was performed aboard the International Space Station (ISS) to video tape the U.S. Lab's condensate venting event with cameras located on the Space Station Remote Manipulator System (SSRMS). Images of the vent plume were acquired close to both the port and starboard vent nozzles. The imaging started with a wider view and then zoomed in closer before the shutdown phase of the vent event occurred. The objective of this experiment was to extend our understanding of the properties of venting liquids into space. Data from the video images were analyzed to obtain the approximate cone angle encompassing the core of the vent plume. The condensate vent plume was characterized as having three phases, a startup phase, a nominal phase, and a shutdown phase. The startup phase consisted of the initial period when the vent first started and the liquid first entered the heated line. The nominal phase was the period when the majority of the liquid was vented. The shutdown phase occurs close to the end of the vent event. The shutdown phase was further divided into two parts, the shutdown initial phase, and a later shutdown sputtering phase. The shutdown initial phase occurs when gas becomes entrained in the condensate liquid being vented. The sputtering phase occurred after the vent valve was closed, and the liquid/ice in the line was removed by continuing to heat the line to bake it out. It was determined that the ice particles were ejected at higher angles, but lower velocities, during the startup and shutdown phases. The number and velocities of ice particles ejected outside of the core region, during the startup, initial shutdown and shutdown sputtering phases were determined. The core of liquid ejected during the startup and shutdown phases was contained within a half cone angle of less than 60 degrees. The startup phase took approximately 36 seconds, the shutdown initial phase took approximately 22 seconds, and the shutdown sputtering phase took approximately 32 seconds. Results from the experiment were correlated with the Boeing ISS vent plume model.

Understanding space science under the northern lights

NASA Astrophysics Data System (ADS)

Koskinen, H.

What is space science? The answers to this question can be very variable indeed. In fact, space research is a field where science, technology, and applications are so closely tied together that it is often difficult to recognize the central role of science. However, as paradoxical as it may sound, it appears that the less-educated public often appreciates the value of space science better than highly educated policy makers and bureaucrats who tend to evaluate the importance of space activities in terms of economic and societal benefits only. In a country like Finland located below the zone, where auroras are visible during the long dark winter nights, the space is perhaps closer to the public than in countries where the visible objects are the Moon, planets and stars somewhere far away. This positive fact has been very useful, for example, in popularization of such an abstract concept as space weather. In Finland it is possible to see space weather and this rises the curiosity about the processes behind this magnificent phenomenon. Of course, also in Finland the beautiful SOHO images of the Sun and the Hubble Space Telescope pictures of the remote universe attract the attention of the large public. We also have an excellent vehicle in increasing the public understanding in the society of Finnish amateur astronomers Ursa. It is an organization for anyone interested in practically everything from visual phenomena in the air to the remote galaxies and the Big Bang. Ursa publishes a high-quality monthly magazine in Finnish and runs local amateur clubs. Last year its 80th birthday exhibition was one of the best-visited public events in Helsinki. It clearly gave a strong evidence of wide public interest in space in general and in space science in particular. Only curious people can grasp the beauty and importance of the underlying science. Thus, we should focus our public space science education and outreach primarily on waking up the curiosity of the public instead of providing ready answers from above.

Modeling the long-term evolution of space debris

DOEpatents

Nikolaev, Sergei; De Vries, Willem H.; Henderson, John R.; Horsley, Matthew A.; Jiang, Ming; Levatin, Joanne L.; Olivier, Scot S.; Pertica, Alexander J.; Phillion, Donald W.; Springer, Harry K.

2017-03-07

A space object modeling system that models the evolution of space debris is provided. The modeling system simulates interaction of space objects at simulation times throughout a simulation period. The modeling system includes a propagator that calculates the position of each object at each simulation time based on orbital parameters. The modeling system also includes a collision detector that, for each pair of objects at each simulation time, performs a collision analysis. When the distance between objects satisfies a conjunction criterion, the modeling system calculates a local minimum distance between the pair of objects based on a curve fitting to identify a time of closest approach at the simulation times and calculating the position of the objects at the identified time. When the local minimum distance satisfies a collision criterion, the modeling system models the debris created by the collision of the pair of objects.

Sharing Space Situational Awareness Data

NASA Astrophysics Data System (ADS)

Bird, D.

2010-09-01

The Commander, United States Strategic Command (CDRUSSTRATCOM) accepted responsibility for sharing space situational awareness (SSA) information/services with commercial & foreign entities from the US Air Force on 22 Dec 09 (formerly the Commercial & Foreign Entities Pilot Program). The requirement to share SSA services with non-US Government (USG) entities is derived from Title 10, United States Code, Section 2274 (2010) and is consistent with the new National Space Policy. US Strategic Command’s (USSTRATCOM’s) sharing of SSA services consists of basic services (Two-Line Elements, decay data and satellite catalog details) available on www.space-track.org and advanced services (conjunction assessment, launch support, etc) available with a signed agreement. USSTRATCOM has requested USG permission to enter into international agreements to enable SSA data exchange with our foreign partners. USSTRATCOM recently authorized Joint Functional Component Command for Space (JFCC SPACE) to share Conjunction Summary Messages (CSMs) with satellite owner/operators whose satellites have been identified as closely approaching another space object. CSMs contain vector and covariance data computed using Special Perturbations theory. To facilitate the utility of the CSMs, USSTRATCOM has and is hosting CSM Workshops to ensure satellite operators fully understand the data contained in the CSM in order to provide an informed recommendation to their leadership. As JFCC SPACE matures its ability to accept ephemeris data from a satellite operator, it will be necessary to automatically transfer that data from one security level to another. USSTRATCOM and Air Force Space Command are coordinating the integration of a cross domain solution that will allow JFCC SPACE to do just that. Finally, USSTRATCOM is also working with commercial and governmental organizations to develop an internationally-accepted conjunction assessment message. The United States Government (USG), specifically the Department of Defense, has been integrating data from diverse sources for decades. In recent years, more and more commercial entities have been integrating our data into their operations, whether to use General Perturbation (GP) Two-Line Elements (TLEs) to perform a rudimentary form of conjunction assessment (CA) or to provide a new app for the iPhone. For the longest time, the USG was one of the few organizations able to fund and conduct space surveillance using optical telescopes and various types of radar. Unfortunately, despite decades of experience tracking objects in space, we had not matured either our equipment or our processes to the point that we were able to prevent the Iridium-Cosmos collision about 18 months ago. As a result, there are two belts of debris orbiting our planet, today and for years to come. As space has become more congested and budgets have shrunk, the need to integrate data has increased. Fortunately, the number of organizations who have developed or are developing space situational awareness (SSA) capabilities, including analytical tools, has also increased.

Burbank closes the Node 2 Hatch

NASA Image and Video Library

2012-03-24

ISS030-E-173920 (24 March 2012) --- NASA astronaut Dan Burbank, Expedition 30 commander, closes a hatch in the International Space Station as crew members prepare to move to the appropriate Soyuz vehicles, due to the possibility that space debris could pass close to the station. NASA astronaut Don Pettit, flight engineer, is at left. Burbank, Shkaplerov and Ivanishin sheltered in the Soyuz TMA-22 spacecraft attached to the Poisk Mini-Research Module 2 (MRM2) while Kononenko, Kuipers and Pettit took to the Soyuz TMA-03M docked to the Rassvet Mini-Research Module 1 (MRM-1).

Potential negative effects of perspective-taking efforts in the context of close relationships: increased bias and reduced satisfaction.

PubMed

Vorauer, Jacquie D; Sucharyna, Tamara A

2013-01-01

Three experiments demonstrated that trying to appreciate a close other's unique point of view (imagine-other perspective taking) increases the extent to which individuals overestimate their own transparency to the close other, that is, how many of their values, preferences, traits, and feelings are readily apparent to him or her. Trying to be objective and pay careful attention to cues from a close other, which inhibits perspective taking, instead had the opposite effect. Mediation analyses suggested that increased focus on the self as an object of evaluation contributed to the positive effect of imagine-other perspective taking on perceived transparency, and decreased focus on the self as an object of evaluation contributed to the negative effect of trying to be objective on these judgments. These effects on perceived transparency had important implications for relationship well-being: Enhanced perceived transparency of negative feelings prompted by imagine-other perspective taking during a back-and-forth exchange with a romantic partner led to systematic discrepancies between individuals' own and their partner's experience of the exchange and reduced relationship satisfaction; trying to be objective instead reduced perceived transparency and thereby increased satisfaction. Notably, initial closeness with another person enhanced rather than tempered the egocentric effects of perspective taking. Taken together, these results suggest that positive motivations to nurture a close relationship and be sensitive to a loved one might sometimes be better channeled toward paying closer attention to his or her behavior than toward perspective taking.

Movement Forms: A Graph-Dynamic Perspective

PubMed Central

Saltzman, Elliot; Holt, Ken

2014-01-01

The focus of this paper is on characterizing the physical movement forms (e.g., walk, crawl, roll, etc.) that can be used to actualize abstract, functionally-specified behavioral goals (e.g., locomotion). Emphasis is placed on how such forms are distinguished from one another, in part, by the set of topological patterns of physical contact between agent and environment (i.e., the set of physical graphs associated with each form) and the transitions among these patterns displayed over the course of performance (i.e., the form’s physical graph dynamics). Crucial in this regard is the creation and dissolution of loops in these graphs, which can be related to the distinction between open and closed kinematic chains. Formal similarities are described within the theoretical framework of task-dynamics between physically-closed kinematic chains (physical loops) that are created during various movement forms and functionally-closed kinematic chains (functional loops) that are associated with task-space control of end-effectors; it is argued that both types of loop must be flexibly incorporated into the coordinative structures that govern skilled action. Final speculation is focused on the role of graphs and their dynamics, not only in processes of coordination and control for individual agents, but also in processes of inter-agent coordination and the coupling of agents with (non-sentient) environmental objects. PMID:24910507

Movement Forms: A Graph-Dynamic Perspective.

PubMed

Saltzman, Elliot; Holt, Ken

2014-01-01

The focus of this paper is on characterizing the physical movement forms (e.g., walk, crawl, roll, etc.) that can be used to actualize abstract, functionally-specified behavioral goals (e.g., locomotion). Emphasis is placed on how such forms are distinguished from one another, in part, by the set of topological patterns of physical contact between agent and environment (i.e., the set of physical graphs associated with each form) and the transitions among these patterns displayed over the course of performance (i.e., the form's physical graph dynamics ). Crucial in this regard is the creation and dissolution of loops in these graphs, which can be related to the distinction between open and closed kinematic chains. Formal similarities are described within the theoretical framework of task-dynamics between physically-closed kinematic chains (physical loops) that are created during various movement forms and functionally-closed kinematic chains (functional loops) that are associated with task-space control of end-effectors; it is argued that both types of loop must be flexibly incorporated into the coordinative structures that govern skilled action. Final speculation is focused on the role of graphs and their dynamics, not only in processes of coordination and control for individual agents, but also in processes of inter-agent coordination and the coupling of agents with (non-sentient) environmental objects.

DANCING IN THE DARK: NEW BROWN DWARF BINARIES FROM KERNEL PHASE INTERFEROMETRY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pope, Benjamin; Tuthill, Peter; Martinache, Frantz, E-mail: bjsp@physics.usyd.edu.au, E-mail: p.tuthill@physics.usyd.edu.au, E-mail: frantz@naoj.org

2013-04-20

This paper revisits a sample of ultracool dwarfs in the solar neighborhood previously observed with the Hubble Space Telescope's NICMOS NIC1 instrument. We have applied a novel high angular resolution data analysis technique based on the extraction and fitting of kernel phases to archival data. This was found to deliver a dramatic improvement over earlier analysis methods, permitting a search for companions down to projected separations of {approx}1 AU on NIC1 snapshot images. We reveal five new close binary candidates and present revised astrometry on previously known binaries, all of which were recovered with the technique. The new candidate binariesmore » have sufficiently close separation to determine dynamical masses in a short-term observing campaign. We also present four marginal detections of objects which may be very close binaries or high-contrast companions. Including only confident detections within 19 pc, we report a binary fraction of at least #Greek Lunate Epsilon Symbol#{sub b} = 17.2{sub -3.7}{sup +5.7}%. The results reported here provide new insights into the population of nearby ultracool binaries, while also offering an incisive case study of the benefits conferred by the kernel phase approach in the recovery of companions within a few resolution elements of the point-spread function core.« less

Final test results for the ground operations demonstration unit for liquid hydrogen

NASA Astrophysics Data System (ADS)

Notardonato, W. U.; Swanger, A. M.; Fesmire, J. E.; Jumper, K. M.; Johnson, W. L.; Tomsik, T. M.

2017-12-01

Described herein is a comprehensive project-a large-scale test of an integrated refrigeration and storage system called the Ground Operations and Demonstration Unit for Liquid Hydrogen (GODU LH2), sponsored by the Advanced Exploration Systems Program and constructed at Kennedy Space Center. A commercial cryogenic refrigerator interfaced with a 125,000 l liquid hydrogen tank and auxiliary systems in a manner that enabled control of the propellant state by extracting heat via a closed loop Brayton cycle refrigerator coupled to a novel internal heat exchanger. Three primary objectives were demonstrating zero-loss storage and transfer, gaseous liquefaction, and propellant densification. Testing was performed at three different liquid hydrogen fill-levels. Data were collected on tank pressure, internal tank temperature profiles, mass flow in and out of the system, and refrigeration system performance. All test objectives were successfully achieved during approximately two years of testing. A summary of the final results is presented in this paper.

Large scale tracking algorithms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, Ross L.; Love, Joshua Alan; Melgaard, David Kennett

2015-01-01

Low signal-to-noise data processing algorithms for improved detection, tracking, discrimination and situational threat assessment are a key research challenge. As sensor technologies progress, the number of pixels will increase signi cantly. This will result in increased resolution, which could improve object discrimination, but unfortunately, will also result in a significant increase in the number of potential targets to track. Many tracking techniques, like multi-hypothesis trackers, suffer from a combinatorial explosion as the number of potential targets increase. As the resolution increases, the phenomenology applied towards detection algorithms also changes. For low resolution sensors, "blob" tracking is the norm. For highermore » resolution data, additional information may be employed in the detection and classfication steps. The most challenging scenarios are those where the targets cannot be fully resolved, yet must be tracked and distinguished for neighboring closely spaced objects. Tracking vehicles in an urban environment is an example of such a challenging scenario. This report evaluates several potential tracking algorithms for large-scale tracking in an urban environment.« less

Some inconvenient truths about biosignatures involving two chemical species on Earth-like exoplanets.

PubMed

Rein, Hanno; Fujii, Yuka; Spiegel, David S

2014-05-13

The detection of strong thermochemical disequilibrium in the atmosphere of an extrasolar planet is thought to be a potential biosignature. In this article we present a previously unidentified kind of false positive that can mimic a disequilibrium or any other biosignature that involves two chemical species. We consider a scenario where the exoplanet hosts a moon that has its own atmosphere and neither of the atmospheres is in chemical disequilibrium. Our results show that the integrated spectrum of the planet and the moon closely resembles that of a single object in strong chemical disequilibrium. We derive a firm limit on the maximum spectral resolution that can be obtained for both directly imaged and transiting planets. The spectral resolution of even idealized space-based spectrographs that might be achievable in the next several decades is in general insufficient to break the degeneracy. Both chemical species can only be definitively confirmed in the same object if absorption features of both chemicals can be unambiguously identified and their combined depth exceeds 100%.

The Near Earth Object (NEO) Scout Spacecraft: A Low-cost Approach to In-situ Characterization of the NEO Population

NASA Technical Reports Server (NTRS)

Woeppel, Eric A.; Balsamo, James M.; Fischer, Karl J.; East, Matthew J.; Styborski, Jeremy A.; Roche, Christopher A.; Ott, Mackenzie D.; Scorza, Matthew J.; Doherty, Christopher D.; Trovato, Andrew J.;

Dangerous Spaces: Threatening Sites for Social Justice

ERIC Educational Resources Information Center

Schostak, John

2012-01-01

There is nothing natural about space as it is understood here. Spacing is an act that constructs relationships, intervals, separations and thus boundaries. The earth has no territories other than those imagined and enforced through acts of territorialisation. A city has its private spaces closed to open access and open spaces that are inscribed…

Closeup view looking into the nozzle of the Space Shuttle ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Close-up view looking into the nozzle of the Space Shuttle Main Engine number 2061 looking at the cooling tubes along the nozzle wall and up towards the Main Combustion Chamber and Injector Plate - Space Transportation System, Space Shuttle Main Engine, Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

46 CFR 169.315 - Ventilation (other than machinery spaces).

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Ventilation (other than machinery spaces). 169.315... spaces). (a) All enclosed spaces within the vessel must be properly ventilated in a manner suitable for the purpose of the space. (b) A means must be provided to close off all vents and ventilators. (c...

46 CFR 169.315 - Ventilation (other than machinery spaces).

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Ventilation (other than machinery spaces). 169.315... spaces). (a) All enclosed spaces within the vessel must be properly ventilated in a manner suitable for the purpose of the space. (b) A means must be provided to close off all vents and ventilators. (c...

46 CFR 169.315 - Ventilation (other than machinery spaces).

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Ventilation (other than machinery spaces). 169.315... spaces). (a) All enclosed spaces within the vessel must be properly ventilated in a manner suitable for the purpose of the space. (b) A means must be provided to close off all vents and ventilators. (c...

46 CFR 169.315 - Ventilation (other than machinery spaces).

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Ventilation (other than machinery spaces). 169.315... spaces). (a) All enclosed spaces within the vessel must be properly ventilated in a manner suitable for the purpose of the space. (b) A means must be provided to close off all vents and ventilators. (c...

Closed-ecology life support systems /CELSS/ for long-duration, manned missions

NASA Technical Reports Server (NTRS)

Modell, M.; Spurlock, J. M.

1979-01-01

Studies were conducted to scope the principal areas of technology that can contribute to the development of closed-ecology life support systems (CELSS). Such systems may be required for future space activities, such as space stations, manufacturing facilities, or colonies. A major feature of CELSS is the regeneration of food from carbon in waste materials. Several processes, using biological and/or physico-chemical components, have been postulated for closing the recycle loop. At the present time, limits of available technical information preclude the specification of an optimum scheme. Nevertheless, the most significant technical requirements can be determined by way of an iterative procedure of formulating, evaluating and comparing various closed-system scenario. The functions features and applications of this systems engineering procedure are discussed.

Peripersonal space representation develops independently from visual experience.

PubMed

Ricciardi, Emiliano; Menicagli, Dario; Leo, Andrea; Costantini, Marcello; Pietrini, Pietro; Sinigaglia, Corrado

2017-12-15

Our daily-life actions are typically driven by vision. When acting upon an object, we need to represent its visual features (e.g. shape, orientation, etc.) and to map them into our own peripersonal space. But what happens with people who have never had any visual experience? How can they map object features into their own peripersonal space? Do they do it differently from sighted agents? To tackle these questions, we carried out a series of behavioral experiments in sighted and congenitally blind subjects. We took advantage of a spatial alignment effect paradigm, which typically refers to a decrease of reaction times when subjects perform an action (e.g., a reach-to-grasp pantomime) congruent with that afforded by a presented object. To systematically examine peripersonal space mapping, we presented visual or auditory affording objects both within and outside subjects' reach. The results showed that sighted and congenitally blind subjects did not differ in mapping objects into their own peripersonal space. Strikingly, this mapping occurred also when objects were presented outside subjects' reach, but within the peripersonal space of another agent. This suggests that (the lack of) visual experience does not significantly affect the development of both one's own and others' peripersonal space representation.

Modal parameter identification based on combining transmissibility functions and blind source separation techniques

NASA Astrophysics Data System (ADS)

Araújo, Iván Gómez; Sánchez, Jesús Antonio García; Andersen, Palle

2018-05-01

Transmissibility-based operational modal analysis is a recent and alternative approach used to identify the modal parameters of structures under operational conditions. This approach is advantageous compared with traditional operational modal analysis because it does not make any assumptions about the excitation spectrum (i.e., white noise with a flat spectrum). However, common methodologies do not include a procedure to extract closely spaced modes with low signal-to-noise ratios. This issue is relevant when considering that engineering structures generally have closely spaced modes and that their measured responses present high levels of noise. Therefore, to overcome these problems, a new combined method for modal parameter identification is proposed in this work. The proposed method combines blind source separation (BSS) techniques and transmissibility-based methods. Here, BSS techniques were used to recover source signals, and transmissibility-based methods were applied to estimate modal information from the recovered source signals. To achieve this combination, a new method to define a transmissibility function was proposed. The suggested transmissibility function is based on the relationship between the power spectral density (PSD) of mixed signals and the PSD of signals from a single source. The numerical responses of a truss structure with high levels of added noise and very closely spaced modes were processed using the proposed combined method to evaluate its ability to identify modal parameters in these conditions. Colored and white noise excitations were used for the numerical example. The proposed combined method was also used to evaluate the modal parameters of an experimental test on a structure containing closely spaced modes. The results showed that the proposed combined method is capable of identifying very closely spaced modes in the presence of noise and, thus, may be potentially applied to improve the identification of damping ratios.