Science.gov

Sample records for tumble rates rendezvousing

  1. Optical Survey of the Tumble Rates of Retired GEO Satellites

    NASA Astrophysics Data System (ADS)

    Binz, C.; Davis, M.; Kelm, B.; Moore, C.

    2014-09-01

    The Naval Research Lab (NRL) and the Defense Advanced Research Projects Agency (DARPA) have made significant progress toward robotic rendezvous and docking between spacecraft, however the long-term attitude motion evolution of uncontrolled resident space objects has never been well-characterized. This effort set out to identify the motion exhibited in retired satellites at or near geosynchronous orbit (GEO). Through analysis of the periodic structure of observed reflected light curves, estimated tumble rates were determined for several retired satellites, typically in a super-GEO disposal orbit. The NRL's 1-meter telescope at Midway Research Center was used to track and observe the objects while the sun-satellite-observer geometry was most favorable; typically over a one- to two-hour period, repeated multiple times over the course of weeks. By processing each image with calibration exposures, the relative apparent magnitude of the brightness of the object over time was determined. Several tools, including software developed internally, were used for frequency analysis of the brightness curves. Results show that observed satellites generally exhibit a tumble rate well below the notional bounding case of one degree per second. When harmonics are found to exist in the data, modeling and simulation of the optical characteristics of the satellite can help to resolve ambiguities. This process was validated on spacecraft for which an attitude history is known, and agreement was found.

  2. Automated rendezvous and docking: A parametric study

    NASA Technical Reports Server (NTRS)

    Dabney, R.

    1984-01-01

    A technique for achieving autonomous rendezvous and docking of two orbiting space vehicles is described. Results of a digital computer simulation of the technique are presented and used to evaluate its performance under a wide variety of conditions, including docking with tumbling spacecraft. The interrelationships between initial range, tumbling rates, fuel consumption, and time requirements are explored. Factors which limit performance are identified and beneficial modifications proposed.

  3. SCIENCE RENDEZVOUS KINGSTON 20152 3SCIENCE RENDEZVOUS KINGSTON 2015

    E-print Network

    Things to do at Science Rendezvous Kingston #12;Title Bar SCIENCE RENDEZVOUS KINGSTON 20158 Rube Goldberg Machines #12;Title Bar 9SCIENCE RENDEZVOUS KINGSTON 2015 The Incredible World Of Bugs #12;Title Bar SCIENCE

  4. Comet rendezvous mission study

    NASA Technical Reports Server (NTRS)

    Friedlander, A. L.; Wells, W. C.

    1971-01-01

    Four periodic comets with perihelia between 1980 and 1986 (Encke, d'Arrest, Kipff, and Halley) are used as candidates for the comet rendezvous mission study. All these comet apparitions are especially favorable for rendezvous missions, because of early earth-based comet recovery, good opportunities to view their activity from earth, and reasonable launch vehicle and trajectory requirements for nominal payloads.

  5. Effective run-and-tumble dynamics of bacteria baths

    NASA Astrophysics Data System (ADS)

    Paoluzzi, M.; Di Leonardo, R.; Angelani, L.

    2013-10-01

    E. coli bacteria swim in straight runs interrupted by sudden reorientation events called tumbles. The resulting random walks give rise to density fluctuations that can be derived analytically in the limit of non-interacting particles or equivalently of very low concentrations. However, in situations of practical interest, the concentration of bacteria is always large enough to make interactions an important factor. Using molecular dynamics simulations, we study the dynamic structure factor of a model bacterial bath for increasing values of densities. We show that it is possible to reproduce the dynamics of density fluctuations in the system using a free run-and-tumble model with effective fitting parameters. We discuss the dependence of these parameters, e.g., the tumbling rate, tumbling time and self-propulsion velocity, on the density of the bath.

  6. Effective run-and-tumble dynamics of bacteria baths

    E-print Network

    M. Paoluzzi; R. Di Leonardo; L. Angelani

    2013-07-30

    {\\it E. coli} bacteria swim in straight runs interrupted by sudden reorientation events called tumbles. The resulting random walks give rise to density fluctuations that can be derived analytically in the limit of non interacting particles or equivalently of very low concentrations. However, in situations of practical interest, the concentration of bacteria is always large enough to make interactions an important factor. Using molecular dynamics simulations, we study the dynamic structure factor of a model bacterial bath for increasing values of densities. We show that it is possible to reproduce the dynamics of density fluctuations in the system using a free run-and-tumble model with effective fitting parameters. We discuss the dependence of these parameters, e.g., the tumbling rate, tumbling time and self-propulsion velocity, on the density of the bath.

  7. First-passage time of run-and-tumble particles

    E-print Network

    L. Angelani; R. Di Leonardo; M. Paoluzzi

    2015-06-26

    We solve the problem of first-passage time for run-and-tumble particles in one dimension. Exact expression is derived for the mean first-passage time in the general case, considering external force-fields and chemotactic-fields, giving rise to space dependent swim-speed and tumble rate. Agreement between theoretical formulae and numerical simulations is obtained in the analyzed case studies -- constant and sinusoidal force fields, constant gradient chemotactic field. Reported findings can be useful to get insights into very different phenomena involving active particles, such as bacterial motion in external fields, intracellular transport, cell migration, animal foraging.

  8. Rendezvous with Zarya

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Backdropped against a blanket of heavy cloud cover, the Russian-built FGB, also called Zarya, nears the Space Shuttle Endeavour and the U.S.-built Node 1, also called Unity (foreground). Inside Endeavour's cabin, the STS-88 crew readies the Remote Manipulator System (RMS) for Zarya capture as they await the carefully choreographed dance of the rendezvous.

  9. Calculation of tumbling boundaries of a generic wing-only airliner

    NASA Astrophysics Data System (ADS)

    Khrabrov, A.; Sidoryuk, M.

    2015-06-01

    The aerodynamic model of a generic wing-only airliner configuration is developed for a whole range of angles of attack (-180°. . . +180°), based on experimental data obtained in wind tunnels using static, and forced oscillations. Two different approaches for the tumbling boundaries calculation are used. In the first approach, the steady pitch autorotation is calculated. In the second approach, for various angles of attack, the minimum pitch rate disturbance is considered which can result in tumbling. The tumbling boundaries are calculated via the use of a continuation technique. The dependence of these boundaries on such parameters as flight altitude, aircraft center of gravity position, and total velocity is analyzed.

  10. The tumbling spin state of (99942) Apophis

    NASA Astrophysics Data System (ADS)

    Pravec, P.; Scheirich, P.; ?urech, J.; Pollock, J.; Kušnirák, P.; Hornoch, K.; Galád, A.; Vokrouhlický, D.; Harris, A. W.; Jehin, E.; Manfroid, J.; Opitom, C.; Gillon, M.; Colas, F.; Oey, J.; Vraštil, J.; Reichart, D.; Ivarsen, K.; Haislip, J.; LaCluyze, A.

    2014-05-01

    Our photometric observations of Asteroid (99942) Apophis from December 2012 to April 2013 revealed it to be in a state of non-principal axis rotation (tumbling). We constructed its spin and shape model and found that it is in a moderately excited Short Axis Mode (SAM) state with a ratio of the rotational kinetic energy to the basic spin state energy E/E0=1.024±0.013. (All quoted uncertainties correspond to 3?.) The greatest and intermediate principal moments of inertia are nearly the same with I2/I3=0.965-0.015+0.009, but the smallest principal moment of inertia is substantially lower with I1/I3=0.61-0.08+0.11; the asteroid’s dynamically equivalent ellipsoid is close to a prolate ellipsoid. The precession and rotation periods are P?=27.38±0.07 h and P?=263±6 h, respectively; the strongest observed lightcurve amplitude for the SAM case is in the 2nd harmonic of P1=P=30.56±0.01 h. The rotation is retrograde with the angular momentum vector’s ecliptic longitude and latitude of 250° and -75° (the uncertainty area is approximately an ellipse with the major and minor semiaxes of 27° and 14°, respectively). An implication of the retrograde rotation is a somewhat increased probability of the Apophis’ impact in 2068, but it is still very small with the risk level on the Palermo Scale remaining well below zero. Apophis is a member of the population of slowly tumbling asteroids. Applying the theory of asteroid nutational damping by Breiter et al. (Breiter, S., Ro?ek, A., Vokrouhlický, D. [2012]. Mon. Not. R. Astron. Soc. 427, 755-769), we found that slowly tumbling asteroids predominate in the spin rate-size range where their estimated damping times are greater than about 0.2 Gyr. The appearance that the PA/NPA rotators transition line seems to follow a line of constant damping time may be because there are two or more asteroid spin evolution mechanisms in play, or the factor of ?Q (the elastic modulus times the quality factor) is not constant but it may decrease with decreasing asteroid size, which would oppose the trend due to decreasing collisional age or excitation time.

  11. An extension of generalized Taylor dispersion in unbounded homogeneous shear flows to run-and-tumble chemotactic bacteria

    E-print Network

    Bearon, Rachel

    -and-tumble chemotactic bacteria R. N. Bearon School of Oceanography, Box 357940, University of Washington, Seattle of flow, the biased random walk of bacteria such as Escherichia coli is modeled by straight runs. In the well-studied situation of weak bias in tumble rate, bacteria disperse over a diffusive time scale

  12. Near Earth asteroid rendezvous

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The Spacecraft Design Course is the capstone design class for the M.S. in astronautics at the Naval Postgraduate School. The Fall 92 class designed a spacecraft for the Near Earth Asteroid Rendezvous Mission (NEAR). The NEAR mission uses a robotic spacecraft to conduct up-close reconnaissance of a near-earth asteroid. Such a mission will provide information on Solar System formation and possible space resources. The spacecraft is intended to complete a NEAR mission as a relatively low-budget program while striving to gather as much information about the target asteroid as possible. A complete mission analysis and detailed spacecraft design were completed. Mission analysis includes orbit comparison and selection, payload and telemetry requirements, spacecraft configuration, and launch vehicle selection. Spacecraft design includes all major subsystems: structure, electrical power, attitude control, propulsion, payload integration, and thermal control. The resulting spacecraft demonstrates the possibility to meet the NEAR mission requirements using existing technology, 'off-the-shelf' components, and a relatively low-cost launch vehicle.

  13. History of Space Shuttle Rendezvous

    NASA Technical Reports Server (NTRS)

    Goodman, John L.

    2011-01-01

    This technical history is intended to provide a technical audience with an introduction to the rendezvous and proximity operations history of the Space Shuttle Program. It details the programmatic constraints and technical challenges encountered during shuttle development in the 1970s and over thirty years of shuttle missions. An overview of rendezvous and proximity operations on many shuttle missions is provided, as well as how some shuttle rendezvous and proximity operations systems and flight techniques evolved to meet new programmatic objectives. This revised edition provides additional information on Mercury, Gemini, Apollo, Skylab, and Apollo/Soyuz. Some chapters on the Space Shuttle have been updated and expanded. Four special focus chapters have been added to provide more detailed information on shuttle rendezvous. A chapter on the STS-39 mission of April/May 1991 describes the most complex deploy/retrieve mission flown by the shuttle. Another chapter focuses on the Hubble Space Telescope servicing missions. A third chapter gives the reader a detailed look at the February 2010 STS-130 mission to the International Space Station. The fourth chapter answers the question why rendezvous was not completely automated on the Gemini, Apollo, and Space Shuttle vehicles.

  14. 40. THIS TUMBLING MILL IN THE GREY IRON FOUNDRY IS ...

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

    40. THIS TUMBLING MILL IN THE GREY IRON FOUNDRY IS USED TO TUMBLE CASTINGS OVER EACH OTHER TO BREAK OFF RUNNERS AND SPRUES. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  15. Nutation damping in viscoelastic tumbling rotators

    NASA Astrophysics Data System (ADS)

    Frouard, Julien; Efroimsky, Michael

    2015-11-01

    Presently, 138 asteroids show signs of being in non-principal spin states (Warner et al. 2009, updated September 2015). Such spin is often called `tumble' or `wobble'. The instantaneous rotation axis of a wobbling body performs nutation about the direction of the (conserved) angular-momentum vector. Incited by collisions and YORP, wobble is mitigated by internal dissipation due to the nutation-caused alternating stresses inside the asteroid.The knowledge of the timescale related to the damping of the nutation angle is complementary to the knowledge of the timescales associated with collisions and YORP. Previous evaluations of the nutation relaxation rate were based on an inherently inconsistent approach that may be called "Q-model". First, the elastic energy in a periodically deforming rotator was calculated in assumption of the deformation being elastic. Therefrom, the energy dissipation rate was determined by introducing an ad hoc quality factor Q. This ignored the fact that friction (and the ensuing existence of Q) is due to deviation from elasticity.We use the viscoelastic Maxwell model which naturally implies dissipation (as any other viscoelastic model would). In this approach, we compute the power and damping time for an oblate ellipsoid and a prism. Now, the viscosity assumes the role of the product ?Q in the empirical Q-model, with ? being the rigidity. Contrarily to the Q-model, our model naturally gives a null dissipation for a shape tending to a sphere. We also explore when the constant part of the stress can be ignored in the derivation of the damping time. The neglect of prestressing turns out to be legitimate for the mean viscosity exceeding a certain threshold value.

  16. Tumble-mix anaerobic digestion of dry beef manure

    SciTech Connect

    Kottwitz, D.; Schulte, D.D.

    1982-12-01

    Anaerobic digestion of beef manure at an influent total solids concentration of 26% was demonstrated using an innovative tumble-mix fermenter. At an organic loading rate of 4.7 kg VS m-/sup 3/ d-/sup 1/ and a 23% VS influent concentration, a 54% volatile solids reduction was achieved. The average biogas production was 1.37 m/sup 3/ m-/sup 3/ d-/sup 1/ with a gas quality of 54% CH/sub 4/.

  17. Hydra Rendezvous and Docking Sensor

    NASA Technical Reports Server (NTRS)

    Roe, Fred; Carrington, Connie

    2007-01-01

    The U.S. technology to support a CEV AR&D activity is mature and was developed by NASA and supporting industry during an extensive research and development program conducted during the 1990's and early 2000 time frame at the Marshall Space Flight Center. Development and demonstration of a rendezvous/docking sensor was identified early in the AR&D Program as the critical enabling technology that allows automated proxinity operations and docking. A first generation rendezvous/docking sensor, the Video Guidance Sensor (VGS) was developed and successfully flown on STS 87 and again on STS 95, proving the concept of a video-based sensor. Advances in both video and signal processing technologies and the lessons learned from the two successful flight experiments provided a baseline for the development of a new generation of video based rendezvous/docking sensor. The Advanced Video Guidance Sensor (AVGS) has greatly increased performance and additional capability for longer-range operation. A Demonstration Automatic Rendezvous Technology (DART) flight experiment was flown in April 2005 using AVGS as the primary proximity operations sensor. Because of the absence of a docking mechanism on the target satellite, this mission did not demonstrate the ability of the sensor to coltrold ocking. Mission results indicate that the rendezvous sensor operated successfully in "spot mode" (2 km acquisition of the target, bearing data only) but was never commanded to "acquire and track" the docking target. Parts obsolescence issues prevent the construction of current design AVGS units to support the NASA Exploration initiative. This flight proven AR&D technology is being modularized and upgraded with additional capabilities through the Hydra project at the Marshall Space Flight Center. Hydra brings a unique engineering approach and sensor architecture to the table, to solve the continuing issues of parts obsolescence and multiple sensor integration. This paper presents an approach to sensor hardware trades, to address the needs of future vehicles that may rendezvous and dock with the International Space Station (ISS). It will also discuss approaches for upgrading AVGS to address parts obsolescence, and concepts for modularizing the sensor to provide configuration flexibility for multiple vehicle applications. Options for complementary sensors to be integrated into the multi-head Hydra system will also be presented. Complementary sensor options include ULTOR, a digital image correlator system that could provide relative six-degree-of-freedom information independently from AVGS, and time-of-flight sensors, which determine the range between vehicles by timing pulses that travel from the sensor to the target and back. Common targets and integrated targets, suitable for use with the multi-sensor options in Hydra, will also be addressed.

  18. STS-134 Re-Rendezvous Design History

    NASA Technical Reports Server (NTRS)

    Stuit, Timothy D.

    2011-01-01

    In preparation to provide the capability for the Orion spacecraft to rendezvous with the International Space Station (ISS), a new suite of relative navigation sensors are in development and will be tested on one of the final Space Shuttle missions to ISS. The National Aeronautics and Space Administration (NASA) commissioned a flight test of prototypes of the instruments on STS-134, in order to test their performance in the space environment during the nominal rendezvous and docking, as well as a re-rendezvous dedicated to testing the prototype sensors following the undocking of the Space Shuttle Orbiter at the end of the mission. Unlike the initial rendezvous and docking, the re-rendezvous profile would replicate the newly designed Orion coelliptic approach trajectory, something never before attempted with the Shuttle Orbiter. Therefore, there were a number of new parameters that needed to be conceived of, designed, and tested for this re-rendezvous to make the flight test successful. And all of this work had to be integrated with the normal operations of the ISS and Shuttle and had to conform to the constraints of the mission and vehicles. The result of this work is a separation and re-rendezvous trajectory design that will prove not only the design of the relative navigation sensors for the Orion vehicle, but also will serve as a proof of concept for the Orion rendezvous trajectory itself. This document presents the analysis and decision making process involved in attaining the final STS-134 re-rendezvous design.

  19. Orbital maneuvers and space rendezvous

    NASA Astrophysics Data System (ADS)

    Butikov, Eugene I.

    2015-12-01

    Several possibilities of launching a space vehicle from the orbital station are considered and compared. Orbital maneuvers discussed in the paper can be useful in designing a trajectory for a specific space mission. The relative motion of orbiting bodies is investigated on examples of spacecraft rendezvous with the space station that stays in a circular orbit around the Earth. An elementary approach is illustrated by an accompanying simulation computer program and supported by a mathematical treatment based on fundamental laws of physics and conservation laws. Material is appropriate for engineers and other personnel involved in space exploration, undergraduate and graduate students studying classical physics and orbital mechanics.

  20. Automated rendezvous and proximity operations

    NASA Technical Reports Server (NTRS)

    Flecklin, Anton F., II

    1991-01-01

    IR&D efforts in recent years have focused on effective means of performing automated rendezvous and proximity operations. The primary focus for application has been to the Space Shuttle Orbiter and potential derivations, such as the Reusable Cargo Vehicle (RCV), studied in FY 1990. All candidate vehicle mission scenarios have included approach to docking or berthing with the Space Station Freedom (SSF). Results to date indicate that application of appropriate guidance algorithms can reduce docking contact or relative offset conditions, resulting in potential simplification of capture systems.

  1. Boom Rendezvous Alternative Docking Approach

    NASA Technical Reports Server (NTRS)

    Bonometti, Joseph A.

    2006-01-01

    Space rendezvous and docking has always been attempted with primarily one philosophic methodology. The slow matching of one vehicle's orbit by a second vehicle and then a final closing sequence that ends in matching the orbits with perfect precision and with near zero relative velocities. The task is time consuming, propellant intensive, risk inherent (plume impingement, collisions, fuel depletion, etc.) and requires substantial hardware mass. The historical background and rationale as to why this approach is used is discussed in terms of the path-not-taken and in light of an alternate methodology. Rendezvous and docking by boom extension is suggested to have inherent advantages that today s technology can readily exploit. Extension from the primary spacecraft, beyond its inherent large inertia, allows low inertia connections to be made rapidly and safely. Plume contamination issues are eliminated as well as the extra propellant mass and risk required for the final thruster (docking) operations. Space vehicle connection hardware can be significantly lightened. Also, docking sensors and controls require less fidelity; allowing them to be more robust and less sensitive. It is the potential safety advantage and mission risk reduction that makes this approach attractive, besides the prospect of nominal time and mass savings.

  2. Rocket rendezvous at preassigned destinations with optimum entry trajectories

    NASA Astrophysics Data System (ADS)

    Nangia, A. K.

    Optimum entry rendezvous trajectories of commuter rockets between initial noncoaxial coplanar elliptic orbits and destination orbits in an inverse square gravitational field have been determined. Results are presented for an optimum entry rendezvous between earth and Mars. For a given interception angle, the results show that the launch angle for optimum entry rendezvous is smaller than that for the optimum exit rendezvous.

  3. Tumbling and spaceflight: the Gemini VIII experience.

    PubMed

    Mohler, S R; Nicogossian, A E; McCormack, P D; Mohler, S R

    1990-01-01

    A malfunctioning orbital flight attitude thruster during the flight of Gemini VIII led to acceleration forces on astronauts Neil Armstrong (commander) and David Scott (pilot) that created the potential for derogation of oculo-vestibular and eye-hand coordination effects. The spacecraft attained an axial tumbling rotation of 50 rpm and would have exceeded this had not the commander accurately diagnosed the problem and taken immediate corrective action. By the time counter-measure controls were applied, both astronauts were experiencing vertigo and the physiological effects of the tumbling acceleration. Data from the recorders reveal that one astronaut experienced -Gy of 0.92 G-units, and the other +Gy of 0.92 for approximately 46 s. Both received a -Gz of 0.89 G-units from the waist up with a +Gz of 0.05 from the waist down. A substantial increase of time and/or an increase in rpm would ultimately have produced incapacitation of both astronauts. NASA corrected the Gemini thruster problem by changing the ignition system wiring. Future space-craft undertaking long-term missions could be equipped with unambiguous thruster fault displays and could have computer-controlled automatic cutoffs to control excessive thruster burns. PMID:2302130

  4. 14 CFR 1214.111 - Rendezvous services.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... General Provisions Regarding Space Shuttle Flights of Payloads for Non-U...involves the rendezvous of the Space Shuttle orbiter with an orbiting spacecraft...spacecraft deployed earlier on the same Space Shuttle flight. (2) Exchange...

  5. 14 CFR 1214.111 - Rendezvous services.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... General Provisions Regarding Space Shuttle Flights of Payloads for Non-U...involves the rendezvous of the Space Shuttle orbiter with an orbiting spacecraft...spacecraft deployed earlier on the same Space Shuttle flight. (2) Exchange...

  6. 14 CFR 1214.111 - Rendezvous services.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... General Provisions Regarding Space Shuttle Flights of Payloads for Non-U...involves the rendezvous of the Space Shuttle orbiter with an orbiting spacecraft...spacecraft deployed earlier on the same Space Shuttle flight. (2) Exchange...

  7. 14 CFR 1214.111 - Rendezvous services.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... General Provisions Regarding Space Shuttle Flights of Payloads for Non-U...involves the rendezvous of the Space Shuttle orbiter with an orbiting spacecraft...spacecraft deployed earlier on the same Space Shuttle flight. (2) Exchange...

  8. 14 CFR 1214.111 - Rendezvous services.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... General Provisions Regarding Space Shuttle Flights of Payloads for Non-U...involves the rendezvous of the Space Shuttle orbiter with an orbiting spacecraft...spacecraft deployed earlier on the same Space Shuttle flight. (2) Exchange...

  9. 75 FR 44794 - Rendezvous International v.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-29

    ... From the Federal Register Online via the Government Printing Office FEDERAL MARITIME COMMISSION Rendezvous International v. Chief Cargo Services, Inc., Kaiser Apparel, Inc., Edco Logistics, Inc., Oriental.... Karen V. Gregory, Secretary. BILLING CODE P...

  10. Optimum Multi-Impulse Rendezvous Program

    NASA Technical Reports Server (NTRS)

    Glandorf, D. R.; Onley, A. G.; Rozendaal, H. L.

    1970-01-01

    OMIRPROGRAM determines optimal n-impulse rendezvous trajectories under the restrictions of two-body motion in free space. Lawden's primer vector theory is applied to determine optimum number of midcourse impulse applications. Global optimality is not guaranteed.

  11. A testbed for visual based navigation and control during space rendezvous operations

    NASA Astrophysics Data System (ADS)

    Sabatini, Marco; Palmerini, Giovanni B.; Gasbarri, Paolo

    2015-12-01

    Visual based navigation systems are considered essential tools in the framework of close proximity space operations, such as rendezvous and docking, both in the role of primary devices and in the role of back-up systems. Autonomy in such operations is a requirement that has been increasingly underlined, especially in the case of non-cooperative tumbling targets, as for example in the active debris removal concepts. In such a case the time delays and the partial communication coverage make the human intervention unsuitable. On the other hand, robustness of the guidance and control system is certainly an issue for autonomous docking missions. In this paper, algorithms for autonomous relative navigation by means of a single camera are detailed, and tested both numerically and experimentally. At the same time a guidance strategy has been defined in order to increase the system robustness. In order to prove the soundness of the proposed navigation and guidance approach a docking mission has been successfully performed by means of two free floating platforms - a chaser and a target - on an air-bearing table, both in a nominal and in a non-nominal (i.e. with a tumbling target) scenarios.

  12. The Rendezvous Monitoring Display Capabilities of the Rendezvous and Proximity Operations Program

    NASA Technical Reports Server (NTRS)

    Brazzel, Jack; Spehar, Pete; Clark, Fred; Foster, Chris; Eldridge, Erin

    2013-01-01

    The Rendezvous and Proximity Operations Program (RPOP) is a laptop computer- based relative navigation tool and piloting aid that was developed during the Space Shuttle program. RPOP displays a graphical representation of the relative motion between the target and chaser vehicles in a rendezvous, proximity operations and capture scenario. After being used in over 60 Shuttle rendezvous missions, some of the RPOP display concepts have become recognized as a minimum standard for cockpit displays for monitoring the rendezvous task. To support International Space Station (ISS) based crews in monitoring incoming visiting vehicles, RPOP has been modified to allow crews to compare the Cygnus visiting vehicle s onboard navigated state to processed range measurements from an ISS-based, crew-operated Hand Held Lidar sensor. This paper will discuss the display concepts of RPOP that have proven useful in performing and monitoring rendezvous and proximity operations.

  13. Near-Earth Asteroid Rendezvous: mission overview

    NASA Astrophysics Data System (ADS)

    Cheng, A. F.; Santo, A. G.; Heeres, K. J.; Landshof, J. A.; Farquhar, R. W.; Gold, R. E.; Lee, S. C.

    1997-10-01

    The Near-Earth Asteroid Rendezvous (NEAR) mission, the first launch of NASA's Discovery Program, will be the first mission to orbit an asteroid. NEAR will make the first comprehensive scientific measurements of an asteroid's surface composition, geology, physical properties, and internal structure. NEAR launched successfully on February 17, 1996, aboard a Delta II-7925. It will orbit the 20-km-diameter near-Earth asteroid 433 Eros for about 1 year, at a minimum orbit radius of about 35 km from the center of the asteroid. The NEAR is a solar-powered, three-axis stabilized spacecraft with a launch mass including propellant of 805 kg. NEAR uses X band telemetry to the NASA Deep Space Network, with the data rates at Eros up to 8.8 kbits/s using a 34-m High Efficiency (HEF) dish, and up to 26.5 kbits/s using a 70-m dish. A solid-state recorder is accommodated with a memory capacity of 1.8 Gbytes. Attitude control is to 1.7 mrad, line-of-sight pointing stability is within 50 ?rad over 1 s, and post processing attitude knowledge is within 50 ?rad. NEAR accommodates 56 kg of instruments and provides them with 84 W. The instruments are a multispectral imager (MSI), a near-infrared spectrograph (NIS), an X ray/gamma ray spectrometer (XRS/GRS), a magnetometer (MAG), and a laser rangefinder (NLR), while a radio science (RS) investigation uses the coherent X band transponder. NEAR will make a flyby of the C-type asteroid 253 Mathilde in June 1997 and will rendezvous with 433 Eros in February 1999. It will execute an initial slow flyby of Eros, with a flyby speed of 5 m/s and a closest approach distance of 500 km. Subsequently, its orbit will be lowered to 35 km. The NEAR Mission Operations Center and the Science Data Center are at the Johns Hopkins Applied Physics Laboratory. The Science Data Center will maintain the entire NEAR data set on-line, and data from all instruments can be accessed by every member of the NEAR Science Team. Data, including images, are released over the Internet as soon as they are validated.

  14. Running and tumbling with E. coli in polymeric solutions

    E-print Network

    A. E. Patteson; A. Gopinath; M. Goulian; P. E. Arratia

    2015-11-02

    Run-and-tumble motility is widely used by swimming microorganisms including numerous prokaryotic eukaryotic organisms. Here, we experimentally investigate the run-and-tumble dynamics of the bacterium E. coli in polymeric solutions. We find that even small amounts of polymer in solution can drastically change E. coli dynamics: cells tumble less and their velocity increases, leading to an enhancement in cell translational diffusion and a sudden decline in rotational diffusion. We show that suppression of tumbling is due to fluid viscosity while the enhancement in swimming speed is mainly due to fluid elasticity. Visualization of single fluorescently labeled DNA polymers reveals that the flow generated by individual E. coli is sufficiently strong to stretch polymer molecules and induce elastic stresses in the fluid, which in turn can act on the cell in such a way to enhance its transport. Our results show that the transport and spread of chemotactic cells can be independently modified and controlled by the fluid material properties.

  15. Running and tumbling with E. coli in polymeric solutions

    E-print Network

    Patteson, A E; Goulian, M; Arratia, P E

    2015-01-01

    Run-and-tumble motility is widely used by swimming microorganisms including numerous prokaryotic eukaryotic organisms. Here, we experimentally investigate the run-and-tumble dynamics of the bacterium E. coli in polymeric solutions. We find that even small amounts of polymer in solution can drastically change E. coli dynamics: cells tumble less and their velocity increases, leading to an enhancement in cell translational diffusion and a sudden decline in rotational diffusion. We show that suppression of tumbling is due to fluid viscosity while the enhancement in swimming speed is mainly due to fluid elasticity. Visualization of single fluorescently labeled DNA polymers reveals that the flow generated by individual E. coli is sufficiently strong to stretch polymer molecules and induce elastic stresses in the fluid, which in turn can act on the cell in such a way to enhance its transport. Our results show that the transport and spread of chemotactic cells can be independently modified and controlled by the fluid...

  16. Credit PSR. This interior view shows the vacuum tumble dryer. ...

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

    Credit PSR. This interior view shows the vacuum tumble dryer. The tumble dryer is lined with a water jacket to maintain temperature during the drying of ammonium perchlorate ("AP"); water enters and exits the dryer jacket through the pipe fittings along the horizontal center line of the dryer. The wall at the right is constructed to blow out in the event of an explosion - Jet Propulsion Laboratory Edwards Facility, Oxidizer Dryer Building, Edwards Air Force Base, Boron, Kern County, CA

  17. Study of a comet rendezvous mission. Volume 2: Appendices

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Appendices to the comet Encke rendezvous mission consider relative positions of comet, earth and sun; viewing condition for Encke; detection of Taurid meteor streams; ephemeris of comet Encke; microwave and optical techniques in rendezvous mission; approach instruments; electrostatic equilibrium of ion engine spacecraft; comet flyby data for rendezvous spacecraft assembly; observations of P/Encke extracted from a compilation; and summary of technical innovations.

  18. Multiple Radios for Fast Rendezvous in Cognitive Radio Networks

    E-print Network

    Chu, Xiaowen

    . The existing work on rendezvous implicitly assumes that each cognitive user is equipped with one radio (i1 Multiple Radios for Fast Rendezvous in Cognitive Radio Networks Lu Yu, Hai Liu, Yiu-Wing Leung, Xiaowen Chu, and Zhiyong Lin Abstract--Rendezvous is a fundamental operation in cognitive radio networks

  19. Rendezvous radar for the orbital maneuvering vehicle

    NASA Technical Reports Server (NTRS)

    Locke, John W.; Olds, Keith A.; Quaid, Thomas

    1991-01-01

    The Rendezvous Radar Set (RRS) was designed at Motorola's Strategic Electronics Division in Chandler, Arizona, to be a key subsystem aboard NASA's Orbital Maneuvering Vehicle (OMV). The unmanned OMV, which was under development at TRW's Federal Systems Division in Redondo Beach, California, was designed to supplement the Shuttle's satellite delivery, retrieval, and maneuvering activities. The RRS was to be used to locate and then provide the OMV with vectoring information to the target satellite (or Shuttle or Space Station) to aid the OMV in making a minimum fuel consumption approach and rendezvous. The OMV development program was halted by NASA in 1990 just as parts were being ordered for the RRS engineering model. The paper presented describes the RRS design and then discusses new technologies, either under development or planned for development at Motorola, that can be applied to radar or alternative sensor solutions for the Automated Rendezvous and Capture problem.

  20. Trigger Angle Targeting for Orbital Rendezvous

    NASA Astrophysics Data System (ADS)

    Woffinden, David C.; Ben Rose, M.; Geller, David K.

    2008-12-01

    Orbital rendezvous missions often have a co-elliptic approach phase where a chaser vehicle approaches an object with a near-constant relative altitude and relative velocity. A well known orbital rendezvous technique is to trigger the Terminal Phase Initiation (TPI) maneuver when the apparent elevation of the target reaches some nominal angle. The best elevation trigger angle on which to initiate the final transfer maneuver must balance favorable performance characteristics and desirable operational simplicity. A detailed analysis is given deriving the best trigger angles and showing how these results correlate to past missions and how they could potentially influence future ones.

  1. On-Board Rendezvous Targeting for Orion

    NASA Technical Reports Server (NTRS)

    Weeks, Michael W.; DSouza, Christopher N.

    2010-01-01

    The Orion On-board GNC system is among the most complex ever developed for a space mission. It is designed to operate autonomously (independent of the ground). The rendezvous system in particular was designed to operate on the far side of the moon, and in the case of loss-of-communications with the ground. The vehicle GNC system is designed to retarget the rendezvous maneuvers, given a mission plan. As such, all the maneuvers which will be performed by Orion, have been designed and are being incorporated into the flight code.

  2. Modeling E. coli Tumbles by Rotational Diffusion. Implications for Chemotaxis

    PubMed Central

    Saragosti, Jonathan; Silberzan, Pascal; Buguin, Axel

    2012-01-01

    The bacterium Escherichia coli in suspension in a liquid medium swims by a succession of runs and tumbles, effectively describing a random walk. The tumbles randomize incompletely, i.e. with a directional persistence, the orientation taken by the bacterium. Here, we model these tumbles by an active rotational diffusion process characterized by a diffusion coefficient and a diffusion time. In homogeneous media, this description accounts well for the experimental reorientations. In shallow gradients of nutrients, tumbles are still described by a unique rotational diffusion coefficient. Together with an increase in the run length, these tumbles significantly contribute to the net chemotactic drift via a modulation of their duration as a function of the direction of the preceding run. Finally, we discuss the limits of this model in propagating concentration waves characterized by steep gradients. In that case, the effective rotational diffusion coefficient itself varies with the direction of the preceding run. We propose that this effect is related to the number of flagella involved in the reorientation process. PMID:22530021

  3. Optimal cooperative power-limited rendezvous between neighboring circular orbits

    NASA Technical Reports Server (NTRS)

    Coverstone-Carroll, Victoria; Prussing, John E.

    1993-01-01

    A minimum-fuel rendezvous of two power-limited spacecraft is investigated. Both vehicles are active and provide thrust to complete the rendezvous. Total propellant consumption is minimized. Analytical solutions are obtained for cooperative rendezvous in the linearized Hill-Clohessy-Wiltshire gravity field. The optimal solutions depend in a complicated way on the power-to-mass ratios of the spacecraft, the initial orbits, and the specified transfer time. For comparison purposes, analytical solutions for active-passive rendezvous in the linearized gravity field are also determined. Cooperative rendezvous requires smaller total propellant consumption, resulting in greater payload capability.

  4. Optical Signature Analysis of Tumbling Rocket Bodies via Laboratory Measurements

    NASA Technical Reports Server (NTRS)

    Cowardin, H.; Lederer, S.; Liou, J.-C.

    2012-01-01

    The NASA Orbital Debris Program Office has acquired telescopic lightcurve data on massive intact objects, specifically spent rocket bodies, in order to ascertain tumble rates in support of the Active Debris Removal (ADR) task to help remediate the LEO environment. Rotation rates are needed to plan and develop proximity operations for potential future ADR operations. To better characterize and model optical data acquired from ground-based telescopes, the Optical Measurements Center (OMC) at NASA/JSC emulates illumination conditions in space using equipment and techniques that parallel telescopic observations and source-target-sensor orientations. The OMC employs a 75-watt Xenon arc lamp as a solar simulator, an SBIG CCD camera with standard Johnson/Bessel filters, and a robotic arm to simulate an object's position and rotation. The light source is mounted on a rotary arm, allowing access any phase angle between 0 -- 360 degrees. The OMC does not attempt to replicate the rotation rates, but focuses on how an object is rotating as seen from multiple phase angles. The two targets studied are scaled (1:48), SL-8 Cosmos 3M second stages. The first target is painted in the standard government "gray" scheme and the second target is primary white, as used for commercial missions. This paper summarizes results of the two scaled rocket bodies, each rotated about two primary axes: (a) a spin-stabilized rotation and (b) an end-over-end rotation. The two rotation states are being investigated as a basis for possible spin states of rocket bodies, beginning with simple spin states about the two primary axes. The data will be used to create a database of potential spin states for future works to convolve with more complex spin states. The optical signatures will be presented for specific phase angles for each rocket body and shown in conjunction with acquired optical data from multiple telescope sources.

  5. Multiple NEO Rendezvous Using Solar Sails

    NASA Technical Reports Server (NTRS)

    Johnson, Les; Alexander, Leslie; Fabisinski, Leo; Heaton, Andy; Miernik, Janie; Stough, Rob; Wright, Roosevelt; Young, Roy

    2012-01-01

    Mission concept is to assess the feasibility of using solar sail propulsion to enable a robotic precursor that would survey multiple Near Earth Objects (NEOs) for potential future human visits. Single spacecraft will rendezvous with and image 3 NEOs within 6 years of launch

  6. Multiple NEO Rendezvous Using Solar Sail Propulsion

    NASA Technical Reports Server (NTRS)

    Johnson, Les; Alexander, Leslie; Fabisinski, Leo; Heaton, Andy; Miernik, Janie; Stough, Rob; Wright, Roosevelt; Young, Roy

    2012-01-01

    The NASA Marshall Space Flight Center (MSFC) Advanced Concepts Office performed an assessment of the feasibility of using a near-term solar sail propulsion system to enable a single spacecraft to perform serial rendezvous operations at multiple Near Earth Objects (NEOs) within six years of launch on a small-to-moderate launch vehicle. The study baselined the use of the sail technology demonstrated in the mid-2000 s by the NASA In-Space Propulsion Technology Project and is scheduled to be demonstrated in space by 2014 as part of the NASA Technology Demonstration Mission Program. The study ground rules required that the solar sail be the only new technology on the flight; all other spacecraft systems and instruments must have had previous space test and qualification. The resulting mission concept uses an 80-m X 80-m 3-axis stabilized solar sail launched by an Athena-II rocket in 2017 to rendezvous with 1999 AO10, Apophis and 2001 QJ142. In each rendezvous, the spacecraft will perform proximity operations for approximately 30 days. The spacecraft science payload is simple and lightweight; it will consist of only the multispectral imager flown on the Near Earth Asteroid Rendezvous (NEAR) mission to 433 Eros and 253 Mathilde. Most non-sail spacecraft systems are based on the Messenger mission spacecraft. This paper will describe the objectives of the proposed mission, the solar sail technology to be employed, the spacecraft system and subsystems, as well as the overall mission profile.

  7. 14 CFR 1214.111 - Rendezvous services.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Rendezvous services. 1214.111 Section 1214.111 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT General... Space Shuttle flight. (2) Exchange of a spacecraft (or part thereof) delivered to orbit on a...

  8. 14 CFR 1214.111 - Rendezvous services.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Rendezvous services. 1214.111 Section 1214.111 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT General... Space Shuttle flight. (2) Exchange of a spacecraft (or part thereof) delivered to orbit on a...

  9. Red blood cells and other non-spherical capsules in shear flow: oscillatory dynamics and the tank-treading-to-tumbling transition

    E-print Network

    J. M. Skotheim; T. W. Secomb

    2006-05-26

    We consider the motion of red blood cells and other non-spherical microcapsules dilutely suspended in a simple shear flow. Our analysis indicates that depending on the viscosity, membrane elasticity, geometry and shear rate, the particle exhibits either tumbling, tank-treading of the membrane about the viscous interior with periodic oscillations of the orientation angle, or intermittent behavior in which the two modes occur alternately. For red blood cells, we compute the complete phase diagram and identify a novel tank-treading-to-tumbling transition at low shear rates. Observations of such motions coupled with our theoretical framework may provide a sensitive means of assessing capsule properties.

  10. Designing the STS-134 Re-Rendezvous: A Preparation for Future Crewed Rendezvous Missions

    NASA Technical Reports Server (NTRS)

    Stuit, Timothy D.

    2011-01-01

    In preparation to provide the capability for the Orion spacecraft, also known as the Multi-Purpose Crew Vehicle (MPCV), to rendezvous with the International Space Station (ISS) and future spacecraft, a new suite of relative navigation sensors are in development and were tested on one of the final Space Shuttle missions to ISS. The National Aeronautics and Space Administration (NASA) commissioned a flight test of prototypes of the Orion relative navigation sensors on STS-134, in order to test their performance in the space environment during the nominal rendezvous and docking, as well as a re-rendezvous dedicated to testing the prototype sensors following the undocking of the Space Shuttle orbiter at the end of the mission. Unlike the rendezvous and docking at the beginning of the mission, the re-rendezvous profile replicates the newly designed Orion coelliptic approach trajectory, something never before attempted with the shuttle orbiter. Therefore, there were a number of new parameters that needed to be conceived of, designed, and tested for this rerendezvous to make the flight test successful. Additionally, all of this work had to be integrated with the normal operations of the ISS and shuttle and had to conform to the constraints of the mission and vehicles. The result of this work is a separation and rerendezvous trajectory design that would not only prove the design of the relative navigation sensors for the Orion vehicle, but also would serve as a proof of concept for the Orion rendezvous trajectory itself. This document presents the analysis and decision making process involved in attaining the final STS-134 re-rendezvous design.

  11. Grinding media oscillation: effect on torsional vibrations in tumble mills 

    E-print Network

    Toram, Kiran Kumar

    2005-11-01

    Tumble mills are hollow cylindrical shells of large diameter carrying grinding media (a combination of rock/iron ore/chemical flakes and metal balls/rods), which, upon rotation of the mill, will be ground into fine powder. These mills rotate at low...

  12. Running and tumbling with E. coli in polymeric solutions

    NASA Astrophysics Data System (ADS)

    Patteson, A. E.; Gopinath, A.; Goulian, M.; Arratia, P. E.

    2015-10-01

    Run-and-tumble motility is widely used by swimming microorganisms including numerous prokaryotic and eukaryotic organisms. Here, we experimentally investigate the run-and-tumble dynamics of the bacterium E. coli in polymeric solutions. We find that even small amounts of polymer in solution can drastically change E. coli dynamics: cells tumble less and their velocity increases, leading to an enhancement in cell translational diffusion and a sharp decline in rotational diffusion. We show that suppression of tumbling is due to fluid viscosity while the enhancement in swimming speed is mainly due to fluid elasticity. Visualization of single fluorescently labeled DNA polymers reveals that the flow generated by individual E. coli is sufficiently strong to stretch polymer molecules and induce elastic stresses in the fluid, which in turn can act on the cell in such a way to enhance its transport. Our results show that the transport and spread of chemotactic cells can be independently modified and controlled by the fluid material properties.

  13. Running and tumbling with E. coli in polymeric solutions.

    PubMed

    Patteson, A E; Gopinath, A; Goulian, M; Arratia, P E

    2015-01-01

    Run-and-tumble motility is widely used by swimming microorganisms including numerous prokaryotic and eukaryotic organisms. Here, we experimentally investigate the run-and-tumble dynamics of the bacterium E. coli in polymeric solutions. We find that even small amounts of polymer in solution can drastically change E. coli dynamics: cells tumble less and their velocity increases, leading to an enhancement in cell translational diffusion and a sharp decline in rotational diffusion. We show that suppression of tumbling is due to fluid viscosity while the enhancement in swimming speed is mainly due to fluid elasticity. Visualization of single fluorescently labeled DNA polymers reveals that the flow generated by individual E. coli is sufficiently strong to stretch polymer molecules and induce elastic stresses in the fluid, which in turn can act on the cell in such a way to enhance its transport. Our results show that the transport and spread of chemotactic cells can be independently modified and controlled by the fluid material properties. PMID:26507950

  14. Tracking techniques for space shuttle rendezvous

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The space shuttle rendezvous radar has a requirement to track cooperative and non-cooperative targets. For this reason the Lunar Module (LM) Rendezvous Radar was modified to incorporate the capability of tracking a non-cooperative target. The modifications are discussed. All modifications except those relating to frequency diversity were completed, and system tests were performed to confirm proper performance in the non-cooperative mode. Frequency diversity was added to the radar and to the special test equipment, and then system tests were performed. This last set of tests included re-running the tests of the non-cooperative mode without frequency diversity, followed by tests with frequency diversity and tests of operation in the original cooperative mode.

  15. Laser space rendezvous and docking tradeoff

    NASA Technical Reports Server (NTRS)

    Adelman, S.; Levinson, S.; Raber, P.; Weindling, F.

    1974-01-01

    A spaceborne laser radar (LADAR) was configured to meet the requirements for rendezvous and docking with a cooperative object in synchronous orbit. The LADAR, configurated using existing pulsed CO2 laser technology and a 1980 system technology baseline, is well suited for the envisioned space tug missions. The performance of a family of candidate LADARS was analyzed. Tradeoff studies as a function of size, weight, and power consumption were carried out for maximum ranges of 50, 100, 200, and 300 nautical miles. The investigation supports the original contention that a rendezvous and docking LADAR can be constructed to offer a cost effective and reliable solution to the envisioned space missions. In fact, the CO2 ladar system offers distinct advantages over other candidate systems.

  16. Orion Handling Qualities During ISS Rendezvous and Docking

    NASA Technical Reports Server (NTRS)

    Hart, Jeremy J.; Stephens, J. P.; Spehar, P.; Bilimoria, K.; Foster, C.; Gonzalex, R.; Sullivan, K.; Jackson, B.; Brazzel, J.; Hart, J.

    2011-01-01

    The Orion spacecraft was designed to rendezvous with multiple vehicles in low earth orbit (LEO) and beyond. To perform the required rendezvous and docking task, Orion must provide enough control authority to perform coarse translational maneuvers while maintaining precision to perform the delicate docking corrections. While Orion has autonomous docking capabilities, it is expected that final approach and docking operations with the International Space Station (ISS) will initially be performed in a manual mode. A series of evaluations was conducted by NASA and Lockheed Martin at the Johnson Space Center to determine the handling qualities (HQ) of the Orion spacecraft during different docking and rendezvous conditions using the Cooper-Harper scale. This paper will address the specifics of the handling qualities methodology, vehicle configuration, scenarios flown, data collection tools, and subject ratings and comments. The initial Orion HQ assessment examined Orion docking to the ISS. This scenario demonstrates the Translational Hand Controller (THC) handling qualities of Orion. During this initial assessment, two different scenarios were evaluated. The first was a nominal docking approach to a stable ISS, with Orion initializing with relative position dispersions and a closing rate of approximately 0.1 ft/sec. The second docking scenario was identical to the first, except the attitude motion of the ISS was modeled to simulate a stress case ( 1 degree deadband per axis and 0.01 deg/sec rate deadband per axis). For both scenarios, subjects started each run on final approach at a docking port-to-port range of 20 ft. Subjects used the THC in pulse mode with cues from the docking camera image, window views, and range and range rate data displayed on the Orion display units. As in the actual design, the attitude of the Orion vehicle was held by the automated flight control system at 0.5 degree deadband per axis. Several error sources were modeled including Reaction Control System (RCS) jet angular and position misalignment, RCS thrust magnitude uncertainty, RCS jet force direction uncertainty due to self plume impingement, and Orion center of mass uncertainty.

  17. KU-Band rendezvous radar performance computer simulation model

    NASA Technical Reports Server (NTRS)

    Griffin, J. W.

    1980-01-01

    The preparation of a real time computer simulation model of the KU band rendezvous radar to be integrated into the shuttle mission simulator (SMS), the shuttle engineering simulator (SES), and the shuttle avionics integration laboratory (SAIL) simulator is described. To meet crew training requirements a radar tracking performance model, and a target modeling method were developed. The parent simulation/radar simulation interface requirements, and the method selected to model target scattering properties, including an application of this method to the SPAS spacecraft are described. The radar search and acquisition mode performance model and the radar track mode signal processor model are examined and analyzed. The angle, angle rate, range, and range rate tracking loops are also discussed.

  18. Multiple exposure of Rendezvous Docking Simulator

    NASA Technical Reports Server (NTRS)

    1964-01-01

    Multiple exposure of Rendezvous Docking Simulator. Francis B. Smith, described the simulator as follows: 'The rendezvous and docking operation of the Gemini spacecraft with the Agena and of the Apollo Command Module with the Lunar Excursion Module have been the subject of simulator studies for several years. [This figure] illustrates the Gemini-Agena rendezvous docking simulator at Langley. The Gemini spacecraft was supported in a gimbal system by an overhead crane and gantry arrangement which provided 6 degrees of freedom - roll, pitch, yaw, and translation in any direction - all controllable by the astronaut in the spacecraft. Here again the controls fed into a computer which in turn provided an input to the servos driving the spacecraft so that it responded to control motions in a manner which accurately simulated the Gemini spacecraft.' Published in Barton C. Hacker and James M. Grimwood, On the Shoulders of Titans: A History of Project Gemini, NASA SP-4203; Francis B. Smith, 'Simulators for Manned Space Research,' Paper presented at the 1966 IEEE International convention, March 21-25, 1966.

  19. Lunar Ascent and Rendezvous Trajectory Design

    NASA Technical Reports Server (NTRS)

    Sostaric, Ronald R.; Merriam, Robert S.

    2008-01-01

    The Lunar Lander Ascent Module (LLAM) will leave the lunar surface and actively rendezvous in lunar orbit with the Crew Exploration Vehicle (CEV). For initial LLAM vehicle sizing efforts, a nominal trajectory, along with required delta-V and a few key sensitivities, is very useful. A nominal lunar ascent and rendezvous trajectory is shown, along with rationale and discussion of the trajectory shaping. Also included are ascent delta-V sensitivities to changes in target orbit and design thrust-to-weight of the vehicle. A sample launch window for a particular launch site has been completed and is included. The launch window shows that budgeting enough delta-V for two missed launch opportunities may be reasonable. A comparison between yaw steering and on-orbit plane change maneuvers is included. The comparison shows that for large plane changes, which are potentially necessary for an anytime return from mid-latitude locations, an on-orbit maneuver is much more efficient than ascent yaw steering. For a planned return, small amounts of yaw steering may be necessary during ascent and must be accounted for in the ascent delta-V budget. The delta-V cost of ascent yaw steering is shown, along with sensitivity to launch site latitude. Some discussion of off-nominal scenarios is also included. In particular, in the case of a failed Powered Descent Initiation burn, the requirements for subsequent rendezvous with the Orion vehicle are outlined.

  20. Hyperbolic Rendezvous at Mars: Risk Assessments and Mitigation Strategies

    NASA Technical Reports Server (NTRS)

    Jedrey, Ricky; Landau, Damon; Whitley, Ryan

    2015-01-01

    Given the current interest in the use of flyby trajectories for human Mars exploration, a key requirement is the capability to execute hyperbolic rendezvous. Hyperbolic rendezvous is used to transport crew from a Mars centered orbit, to a transiting Earth bound habitat that does a flyby. Representative cases are taken from future potential missions of this type, and a thorough sensitivity analysis of the hyperbolic rendezvous phase is performed. This includes early engine cutoff, missed burn times, and burn misalignment. A finite burn engine model is applied that assumes the hyperbolic rendezvous phase is done with at least two burns.

  1. Trajectory control with continuous thrust applied to a rendezvous maneuver

    NASA Astrophysics Data System (ADS)

    Santos, W. G.; Rocco, E. M.

    2013-10-01

    A rendezvous mission can be divided into the following phases: launch, phasing, far range rendezvous, close range rendezvous and mating (docking or berthing). This paper aims to present a close range rendezvous with closed loop controlled straight line trajectory. The approaching is executed on V-bar axis. A PID controller and continuous thrust are used to eliminate the residual errors in the trajectory. A comparative study about the linear and nonlinear dynamics is performed and the results showed that the linear equations become inaccurate insofar as the chaser moves away from the target.

  2. Orbit determination of the Comet Rendezvous/Asteroid Flyby mission - Post-rendezvous phases

    NASA Technical Reports Server (NTRS)

    Miller, James K.; Wood, Lincoln J.; Weeks, Connie J.

    1989-01-01

    Orbit determination during the post-rendezvous phases of the Comet Rendezvous/Asteroid Flyby mission is described. The orbit determination process is discussed, with emphasis placed on optical imaging of landmarks and Doppler tracking. Rotational dynamics are introduced for the cometary nucleus. State estimation errors are given for spacecraft trajectory prediction and cometary nucleus attitude prediction. Estimation errors are also given for parameters that describe the cometary nucleus such as moments of inertia and gravity harmonics. The orbit determination performance in support of science observations while in orbit about the nucleus is described.

  3. Development of Ku-band rendezvous radar tracking and acquisition simulation programs

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The fidelity of the Space Shuttle Radar tracking simulation model was improved. The data from the Shuttle Orbiter Radar Test and Evaluation (SORTE) program experiments performed at the White Sands Missile Range (WSMR) were reviewed and analyzed. The selected flight rendezvous radar data was evaluated. Problems with the Inertial Line-of-Sight (ILOS) angle rate tracker were evaluated using the improved fidelity angle rate tracker simulation model.

  4. A modified Rendezvous ERCP technique in duodenal diverticulum

    PubMed Central

    Odabasi, Mehmet; Yildiz, Mehmet Kamil; Abuoglu, Haci Hasan; Eris, Cengiz; Ozkan, Erkan; Gunay, Emre; Aktekin, Ali; Muftuoglu, MA Tolga

    2013-01-01

    AIM: To postoperative endoscopic retrograde cholangiopancreatography (ERCP) failure, we describe a modified Rendezvous technique for an ERCP in patients operated on for common bile duct stone (CBDS) having a T-tube with retained CBDSs. METHODS: Five cases operated on for CBDSs and having retained stones with a T-tube were referred from other hospitals located in or around Istanbul city to the ERCP unit at the Haydarpasa Numune Education and Research Hospital. Under sedation anesthesia, a sterile guide-wire was inserted via the T-tube into the common bile duct (CBD) then to the papilla. A guide-wire was held by a loop snare and removed through the mouth. The guide-wire was inserted into the sphincterotome via the duodenoscope from the tip to the handle. The duodenoscope was inserted down to the duodenum with a sphincterotome and a guide-wire in the working channel. With the guidance of a guide-wire, the ERCP and sphincterotomy were successfully performed, the guide-wire was removed from the T-tube, the stones were removed and the CBD was reexamined for retained stones by contrast. RESULTS: An ERCP can be used either preoperatively or postoperatively. Although the success rate in an isolated ERCP treatment ranges from up to 87%-97%, 5%-10% of the patients require two or more ERCP treatments. If a secondary ERCP fails, the clinicians must be ready for a laparoscopic or open exploration. A duodenal diverticulum is one of the most common failures in an ERCP, especially in patients with an intradiverticular papilla. For this small group of patients, an antegrade cannulation via a T-tube can improve the success rate up to nearly 100%. CONCLUSION: The modified Rendezvous technique is a very easy method and increases the success of postoperative ERCP, especially in patients with large duodenal diverticula and with intradiverticular papilla. PMID:24255749

  5. Statistical Mechanics of Interacting Run-and-Tumble Bacteria

    NASA Astrophysics Data System (ADS)

    Tailleur, J.; Cates, M. E.

    2008-05-01

    We consider self-propelled particles undergoing run-and-tumble dynamics (as exhibited by E. coli) in one dimension. Building on previous analyses at drift-diffusion level for the one-particle density, we add both interactions and noise, enabling discussion of domain formation by “self-trapping,” and other collective phenomena. Mapping onto detailed-balance systems is possible in certain cases.

  6. Powered Safe Abort for Autonomous Rendezvous of Spacecraft

    E-print Network

    Powered Safe Abort for Autonomous Rendezvous of Spacecraft Louis Breger and Jonathan P. How MIT-optimized rendezvous trajectories. These trajectories guarantee the existence of known powered abort trajectories the existence of known active safe abort trajectories for a large class of possible spacecraft anomalies

  7. X-ray Scattering Studies of Director Tumbling Dynamics in a Nematic Surfactant Solution

    NASA Astrophysics Data System (ADS)

    Caputo, F.; Burghardt, W.

    1998-03-01

    Many cationic surfactants self-assemble into wormlike micelles. At high concentrations, these micellar solutions may then form liquid crystalline nematic phases. Recent studies have demonstrated that the rheology of such solutions is quite similar to that observed in lyotropic liquid crystalline polymers, particularly with respect to stress oscillations in transient flows that are attributed to director tumbling. Here we present complementary rheological and x-ray scattering data on an aqueous solution of cetylpyridinium chloride/hexanol(Sample kindly supplied by L. Walker and J.-F. Berret) to compare the mechanical and structural response. Time-resolved synchtrotron x-ray scattering under shear(Experiments performed at DND-CAT at the APS) is used to measure the average micelle orientation state during transient flows such as step increases and decreases in shear rate, and reversals in flow direction. There is a strong connection between the rheology and the fluid structure: stress minima are well correlated with high instantaneous micellar orientation. The experimental observations are compared with the predictions of the Larson-Doi tumbling polydomain model, which captures many aspects of the observed behavior.

  8. Concept definition study for recovery of tumbling satellites. Volume 1: Executive summary, study results

    NASA Technical Reports Server (NTRS)

    Cable, D. A.; Derocher, W. L., Jr.; Cathcart, J. A.; Keeley, M. G.; Madayev, L.; Nguyen, T. K.; Preese, J. R.

    1986-01-01

    The first assessment is made of the design requirements and conceptual definition of a front end kit to be transported on the currently defined Orbital Maneuvering Vehicle (OMV) and the Space Transportation System Shuttle Orbiter, to conduct remote, teleoperated recovery of disabled and noncontrollable, tumbling satellites. Previous studies did not quantify the dynamic characteristics of a tumbling satellite, nor did they appear to address the full spectrum of Tumbling Satellite Recovery systems requirements. Both of these aspects are investigated with useful results.

  9. SIMONE: interplanetary microsatellites for NEO rendezvous missions

    NASA Astrophysics Data System (ADS)

    Wells, Nigel; Walker, Roger; Green, Simon; Ball, Andrew

    2003-11-01

    The paper summarises a novel mission concept called SIMONE (Smallsat Intercept Missions to Objects Near Earth), whereby a fleet of microsatellites may be deployed to individually rendezvous with a number of Near Earth Objects (NEOs), at very low cost. The mission enables, for the first time, the diverse properties of a range of spectral and physical type NEOs to be determined. Such data are invaluable to the scientific study, impact damage prediction, and impact countermeasure planning of NEOs. The five identical 120kg spacecraft are designed for low-cost piggyback launch on Ariane-5 into GTO, from where each uses a gridded-ion engine to escape the Earth and ultimately to rendezvous with a different NEO target. The primary challenge with such a mission is the ability to accommodate the necessary electric propulsion, power, payload and other onboard systems within the constraints of a microsatellite. The paper describes the way in which the latest technological advancements have been selected and applied to the mission design. The SIMONE design is feasible and clearly demonstrates that the concept of an "interplanetary microsatellite" is now realisable.

  10. Demonstration of autonomous rendezvous technology (DART) project summary

    NASA Astrophysics Data System (ADS)

    Rumford, Timothy E.

    2003-08-01

    Since the 1960s, NASA has performed numerous rendezvous and docking missions. The common element of all US rendezvous and docking is that the spacecraft has always been piloted by astronauts. Only the Russian Space Program has developed and demonstrated an autonomous capability. The Demonstration of Autonomous Rendezvous Technology (DART) project currently funded under NASA's SPace Launch Initiative (SLI) Cycle I , provides a key step in establishing an autonomous rendezvous capaibility for the United States. The Objective of the DART mission is to demonstrate, in space, the hardware and software necessary for autonomous rendezvous. Orbital Sciences Corporation intends to integrate an Advanced Video Guidance Sensor and Autonomous Rendezvous and Proximity Operations algorithms into a Pegasus upper stage in order to demonstrate the capability to autonomously rendezvous with a target currently in orbit. The DART mission will occur in April 2004. The launch site will be Vandenberg AFB and the launch vehicle will be a Pegasus XL equipped with a Hydrazine Auxiliary Propulsion System 4th Stage. All mission objectives will be completed within a 24 hour period. The paper provides a summary of mission objectives, mission overview and a discussion on the design features of the chase and target vehicles.

  11. Orbital rendezvous mission planning using mixed integer nonlinear programming

    NASA Astrophysics Data System (ADS)

    Zhang, Jin; Tang, Guo-jin; Luo, Ya-Zhong; Li, Hai-yang

    2011-04-01

    The rendezvous and docking mission is usually divided into several phases, and the mission planning is performed phase by phase. A new planning method using mixed integer nonlinear programming, which investigates single phase parameters and phase connecting parameters simultaneously, is proposed to improve the rendezvous mission's overall performance. The design variables are composed of integers and continuous-valued numbers. The integer part consists of the parameters for station-keeping and sensor-switching, the number of maneuvers in each rendezvous phase and the number of repeating periods to start the rendezvous mission. The continuous part consists of the orbital transfer time and the station-keeping duration. The objective function is a combination of the propellant consumed, the sun angle which represents the power available, and the terminal precision of each rendezvous phase. The operational requirements for the spacecraft-ground communication, sun illumination and the sensor transition are considered. The simple genetic algorithm, which is a combination of the integer-coded and real-coded genetic algorithm, is chosen to obtain the optimal solution. A practical rendezvous mission planning problem is solved by the proposed method. The results show that the method proposed can solve the integral rendezvous mission planning problem effectively, and the solution obtained can satisfy the operational constraints and has a good overall performance.

  12. Navigation for Rendezvous and Orbit Missions to Small Solar-System Bodies

    NASA Technical Reports Server (NTRS)

    Helfrich, C. E.; Scheeres, D. J.; Williams, B. G.; Bollman, W. E.; Davis, R. P.; Synnott, S. P.; Yeomans, D. K.

    1994-01-01

    All previous spacecraft encounters with small solar-system bodies, such as asteroids and comets, have been flybys (e.g. Galileo's flybys of the asteroids Gaspra and Ida). Several future projects plan to build on the flyby experience and progress to the next level with rendezvous and orbit missions to small bodies. This presents several new issues and challenges for navigation which have never been considered before. This paper addresses these challenges by characterizing the different phases of a small body rendezvous and by describing the navigation requirements and goals of each phase. Prior to the encounter with the small body, improvements to its ephemeris and initial estimates of its physical parameters, e.g. size, shape, mass, rotation rate, rotation pole, and possibly outgassing, are made as accurately as ground-based measurements allow. This characterization can take place over years...

  13. A Tutorial on Model Predictive Control for Spacecraft Rendezvous

    E-print Network

    Hartley, Edward N.

    2015-07-17

    –981, 2007. [4] D. Woffinden and D. Geller, “Navigating the road to autonomous orbital rendezvous,” J. Spacecraft and Rockets, vol. 44, no. 4, pp. 898–909, 2007. [5] Y. Luo, J. Zhang, and G. Tang, “Survey of orbital dynamics and control of space rendezvous... control,” in AIAA Guidance, Navigation and Control Conf. and Exhibit, Austin, TX, Aug 11–14 2003. [16] L. Breger and J. P. How, “Safe trajectories for autonomous rendezvous of spacecraft,” J. Guidance, Control, and Dynamics, vol. 31, no. 5, pp. 1478...

  14. Impact on thin steel plates by tumbling projectiles

    SciTech Connect

    Li, K.; Goldsmith, W.

    1995-12-31

    An experimental, analytical, and numerical investigation into the effects of tumbling projectiles on the impact response of thin 4130 steel target plates was performed. Deformation patterns and failure phenomena as well as the final velocities and trajectories of the projectiles are correlated with initial conditions such as the initial velocity and impact angle (or yaw angle with a zero oblique angle) of the projectile and plate thickness. In the experiments, tumbling motion of the projectiles was induced by impact of a portion of the front face of the projectile with the edge of a massive block placed along the trajectory. Cylinders with a diameter of 12.7 mm, a length of 38.1 mm, and a hardness of R{sub c} 54 were fired at velocities from 400 m/s - 800 m/s. The forward speed of the projectile after tumbling production ranged from 300 m/s-700 m/s. Rotational speeds ranged from 0 rad/s - 3000 rad/s and concomitant impact angles varied from 0{degrees} to 60{degrees}. These parameters were determined from high speed photographic records. The targets were 1.6 mm and 3.2 mm thick. An analytical model developed for thin aluminum target plates was employed in the present study. The model divides the penetration process into three stages: (1) plugging; (2) hole enlargement; and (3) frontal petaling. The processes are quantified using energy dissipation descriptions of the various deformation mechanisms. Numerical simulations of the penetration processes were performed by employment of the program DYNA3D, a nonlinear, three-dimensional finite element code. The material of the target was modeled as elasto-plastic with failure, while the projectile was assumed to be undeformable. The failure criterion of the target is based on the ultimate tensile strain.

  15. Microrheology in tumbling nematics of 8CB liquid crystals

    E-print Network

    Balaji Yendeti; Ashok Vudayagiri

    2015-04-01

    Particle tracking passive microrheology in 8CB liquid crystals is used to redefine the precessional motion of the orientation of nematic director in liquid crystals. Physical origin of tumbling director in presence of presmectic clusters under zero shear conditions is discussed. Different structural properties (pure nematic phase, presmectic(smectic C and smectic A clusters)) were differentiated with characteristic dependence of $G'$ on $\\omega$ in the nematic phase of 8CB liquid crystals. Also, dynamic viscosity is observed with a cross over between parallel and perpendicular components as the smectic A phase is approached.

  16. Rendezvous missions with minimoons from L1

    NASA Astrophysics Data System (ADS)

    Chyba, M.; Haberkorn, T.; Patterson, G.

    2014-07-01

    We propose to present asteroid capture missions with the so-called minimoons. Minimoons are small asteroids that are temporarily captured objects on orbits in the Earth-Moon system. It has been suggested that, despite their small capture probability, at any time there are one or two meter diameter minimoons, and progressively greater numbers at smaller diameters. The minimoons orbits differ significantly from elliptical orbits which renders a rendezvous mission more challenging, however they offer many advantages for such missions that overcome this fact. First, they are already on geocentric orbits which results in short duration missions with low Delta-v, this translates in cost efficiency and low-risk targets. Second, beside their close proximity to Earth, an advantage is their small size since it provides us with the luxury to retrieve the entire asteroid and not only a sample of material. Accessing the interior structure of a near-Earth satellite in its morphological context is crucial to an in-depth analysis of the structure of the asteroid. Historically, 2006 RH120 is the only minimoon that has been detected but work is ongoing to determine which modifications to current observation facilities is necessary to provide detection algorithm capabilities. In the event that detection is successful, an efficient algorithm to produce a space mission to rendezvous with the detected minimoon is highly desirable to take advantage of this opportunity. This is the main focus of our work. For the design of the mission we propose the following. The spacecraft is first placed in hibernation on a Lissajoux orbit around the liberation point L1 of the Earth-Moon system. We focus on eight-shaped Lissajoux orbits to take advantage of the stability properties of their invariant manifolds for our transfers since the cost to minimize is the spacecraft fuel consumption. Once a minimoon has been detected we must choose a point on its orbit to rendezvous (in position and velocities) with the spacecraft. This is determined using a combination of distance between the minimoon's orbit to L1 and its energy level with respect to the Lissajoux orbit on which the spacecraft is hibernating. Once the spacecraft rendezvous with the minimoon, it will escort the temporarily captured object to analyze it until the withdrawal time when the spacecraft exits the orbit to return to its hibernating location awaiting for another minimoon to be detected. The entire mission including the return portion can be stated as an optimal control problem, however we choose to break it into smaller sub-problems as a first step to be refined later. To model our control system, we use the circular three-body problem since it provides a good approximation in the vicinity of the Earth-Moon dynamics. Expansion to more refined models will be considered once the problem has been solved for this first approximation. The problem is solved in several steps. First, we consider the time minimal problem since we will use a multiple of it for the minimal fuel consumption problem with fixed time. The techniques used to produce the transfers involve an indirect method based on the necessary optimality condition of the Pontriagyn maximum principle coupled with a continuation method to address the sensitivity of the numerical algorithm to initial values. Time local optimality is verified by computing the Jacobi fields of the Hamiltonian system associated to our optimal control problem to check the second-order conditions of optimality and determine the non-existence of conjugate points.

  17. Pathfinder autonomous rendezvous and docking project

    NASA Technical Reports Server (NTRS)

    Lamkin, Stephen (editor); Mccandless, Wayne (editor)

    1990-01-01

    Capabilities are being developed and demonstrated to support manned and unmanned vehicle operations in lunar and planetary orbits. In this initial phase, primary emphasis is placed on definition of the system requirements for candidate Pathfinder mission applications and correlation of these system-level requirements with specific requirements. The FY-89 activities detailed are best characterized as foundation building. The majority of the efforts were dedicated to assessing the current state of the art, identifying desired elaborations and expansions to this level of development and charting a course that will realize the desired objectives in the future. Efforts are detailed across all work packages in developing those requirements and tools needed to test, refine, and validate basic autonomous rendezvous and docking elements.

  18. Run-and-tumble dynamics in a crowded environment: Persistent exclusion process for swimmers

    NASA Astrophysics Data System (ADS)

    Soto, Rodrigo; Golestanian, Ramin

    2014-01-01

    The effect of crowding on the run-and-tumble dynamics of swimmers such as bacteria is studied using a discrete lattice model of mutually excluding particles that move with constant velocity along a direction that is randomized at a rate ?. In stationary state, the system is found to break into dense clusters in which particles are trapped or stopped from moving. The characteristic size of these clusters predominantly scales as ?-0.5 in both one and two dimensions. For a range of densities, due to cooperative effects, the stopping time scales as T1d0.85 and as T2d0.8, where Td is the diffusive time associated with the motion of cluster boundaries. Our findings might be helpful in understanding the early stages of biofilm formation.

  19. 76 FR 37663 - Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Tumbling Creek...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-28

    ... proposed critical habitat designation for the Tumbling Creek cavesnail on June 23, 2010 (75 FR 35751... cavesnail, refer to the final listing rule published in the Federal Register on August 14, 2002 (67 FR 52879... Federal Actions The Tumbling Creek cavesnail was emergency listed on December 27, 2001 (66 FR 66803)...

  20. Robust optimization of nonlinear impulsive rendezvous with uncertainty

    NASA Astrophysics Data System (ADS)

    Luo, YaZhong; Yang, Zhen; Li, HengNian

    2014-04-01

    The optimal rendezvous trajectory designs in many current research efforts do not incorporate the practical uncertainties into the closed loop of the design. A robust optimization design method for a nonlinear rendezvous trajectory with uncertainty is proposed in this paper. One performance index related to the variances of the terminal state error is termed the robustness performance index, and a two-objective optimization model (including the minimum characteristic velocity and the minimum robustness performance index) is formulated on the basis of the Lambert algorithm. A multi-objective, non-dominated sorting genetic algorithm is employed to obtain the Pareto optimal solution set. It is shown that the proposed approach can be used to quickly obtain several inherent principles of the rendezvous trajectory by taking practical errors into account. Furthermore, this approach can identify the most preferable design space in which a specific solution for the actual application of the rendezvous control should be chosen.

  1. Planning and scheduling proximity operations for autonomous orbital rendezvous

    E-print Network

    Guerra, Christopher J., 1978-

    2003-01-01

    This thesis develops a mixed integer programming formulation to solve the proximity operations scheduling problem for autonomous orbital rendezvous. The algorithm of this thesis allows the operator to specify planned modes, ...

  2. Mission summary: Halley flyby/Tempel-2 rendezvous

    NASA Technical Reports Server (NTRS)

    Atkins, K.

    1979-01-01

    A unique dual-comet flight opportunity exists in mid-1985 which includes flyby of the large and active comet Halley en route to rendezvous with second comet, Tempel-2. This mission will utilize ion propulsion at a modest performance level, based on proven technology. The Project is planned for FY81 start. Launch occurs in July 1985 via the Shuttle/IUS twin stage. Following IUS injection, the ion propulsion stage provides continuous thrust virtually throughout the 3-year flight until the Tempel-2 rendezvous in 1988. En route, a probe is deployed for encounter with Halley about 4 months after launch at a point 73 days before its perihelion. Rendezvous with Tempel-2 occurs about 60 days before the comet's perihelion during the summer of 1988 and continues for about 1 year. Earth will be in favorable relative positions for observing both the flyby and the rendezvous.

  3. STS-135: Rendezvous Pitch Maneuver - Duration: 3 minutes, 15 seconds.

    NASA Video Gallery

    On July 10, 2011, space shuttle Atlantis performed the nine-minute Rendezvous Pitch Maneuver, or â??backflip.â?ť With Commander Chris Ferguson at the helm, Atlantis rotated 360 degrees backward to ...

  4. STS-134: Rendezvous Pitch Maneuver - Duration: 4 minutes.

    NASA Video Gallery

    On May 18, 2011, space shuttle Endeavour performed the Rendezvous Pitch Maneuver, or "backflip." With Commander Mark Kelly at the helm, Endeavour rotated 360 degrees backward to enable Internationa...

  5. STS-133: Rendezvous Pitch Maneuver - Duration: 4 minutes, 8 seconds.

    NASA Video Gallery

    At 1:15 p.m. EST Saturday, space shuttle Discovery began the nine-minute Rendezvous Pitch Maneuver, or "backflip." With Commander Steve Lindsey at the helm, Discovery rotated 360 degrees backward t...

  6. Apollo experience report: Lunar module landing radar and rendezvous radar

    NASA Technical Reports Server (NTRS)

    Rozas, P.; Cunningham, A. R.

    1972-01-01

    A developmental history of the Apollo lunar module landing and rendezvous radar subsystems is presented. The Apollo radar subsystems are discussed from initial concept planning to flight configuration testing. The major radar subsystem accomplishments and problems are discussed.

  7. Current status of laparoendoscopic rendezvous in the treatment of cholelithiasis with concomitant choledocholithiasis

    PubMed Central

    Baloyiannis, Ioannis; Tzovaras, George

    2015-01-01

    The current evidence in favor of the laparoendoscopic rendezvous is promising and demonstrates the main advantages of this technique in regard to shorter hospital stay and selective cannulation of the common bile duct (CBD), avoiding thus the inadvertent cannulation of the pancreatic duct. In addition, in the rendezvous technique the contrast medium is not injected retrogradely as during the traditional endoscopic retrograde cholangiopancreatography (ERCP), when the medium accidentally could be injected under pressure into the pancreatic duct. The RV technique minimizes that risk. Both these main advantages of the RV technique over the classic ERCP, are related with a significant lower incidence of hyperamylasemia and post-ERCP pancreatitis, compared with the traditional two stage procedure. Choledocholithiasis is present in 10% to 15% of patients undergoing cholecystectomy. To date, the ideal management of CBD stones remains controversial. Prospective randomized trials have shown that laparoscopic management of the CBD stones, as a single stage procedure, is the most efficient and cost effective method of treatment. Laparoendoscopic rendezvous has been proposed as an alternative single stage approach. Several studies have shown the effective use of this technique in the treatment of CBD stones by improving patient compliance and clinical results including shorter hospital stay, higher success rate and less cost. The current evidence about the use of this technique presented in this review article is promising and demonstrates the main advantages of the procedure. PMID:26140098

  8. Imaging flash LIDAR for safe landing on solar system bodies and spacecraft rendezvous and docking

    NASA Astrophysics Data System (ADS)

    Amzajerdian, Farzin; Roback, Vincent E.; Bulyshev, Alexander E.; Brewster, Paul F.; Carrion, William A.; Pierrottet, Diego F.; Hines, Glenn D.; Petway, Larry B.; Barnes, Bruce W.; Noe, Anna M.

    2015-05-01

    NASA has been pursuing flash lidar technology for autonomous, safe landing on solar system bodies and for automated rendezvous and docking. During the final stages of landing, from about 1 km to 500 m above the ground, the flash lidar can generate 3-Dimensional images of the terrain to identify hazardous features such as craters, rocks, and steep slopes. The onboard flight computer can then use the 3-D map of terrain to guide the vehicle to a safe location. As an automated rendezvous and docking sensor, the flash lidar can provide relative range, velocity, and bearing from an approaching spacecraft to another spacecraft or a space station. NASA Langley Research Center has developed and demonstrated a flash lidar sensor system capable of generating 16k pixels range images with 7 cm precision, at a 20 Hz frame rate, from a maximum slant range of 1800 m from the target area. This paper describes the lidar instrument and presents the results of recent flight tests onboard a rocket-propelled free-flyer vehicle (Morpheus) built by NASA Johnson Space Center. The flights were conducted at a simulated lunar terrain site, consisting of realistic hazard features and designated landing areas, built at NASA Kennedy Space Center specifically for this demonstration test. This paper also provides an overview of the plan for continued advancement of the flash lidar technology aimed at enhancing its performance to meet both landing and automated rendezvous and docking applications.

  9. Imaging Flash Lidar for Safe Landing on Solar System Bodies and Spacecraft Rendezvous and Docking

    NASA Technical Reports Server (NTRS)

    Amzajerdian, Farzin; Roback, Vincent E.; Bulyshev, Alexander E.; Brewster, Paul F.; Carrion, William A; Pierrottet, Diego F.; Hines, Glenn D.; Petway, Larry B.; Barnes, Bruce W.; Noe, Anna M.

    2015-01-01

    NASA has been pursuing flash lidar technology for autonomous, safe landing on solar system bodies and for automated rendezvous and docking. During the final stages of the landing from about 1 kilometer to 500 meters above the ground, the flash lidar can generate 3-Dimensional images of the terrain to identify hazardous features such as craters, rocks, and steep slopes. The onboard flight computer can then use the 3-D map of terrain to guide the vehicle to a safe location. As an automated rendezvous and docking sensor, the flash lidar can provide relative range, velocity, and bearing from an approaching spacecraft to another spacecraft or a space station. NASA Langley Research Center has developed and demonstrated a flash lidar sensor system capable of generating 16,000 pixels range images with 7 centimeters precision, at 20 Hertz frame rate, from a maximum slant range of 1800 m from the target area. This paper describes the lidar instrument and presents the results of recent flight tests onboard a rocket-propelled free-flyer vehicle (Morpheus) built by NASA Johnson Space Center. The flights were conducted at a simulated lunar terrain site, consisting of realistic hazard features and designated landing areas, built at NASA Kennedy Space Center specifically for this demonstration test. This paper also provides an overview of the plan for continued advancement of the flash lidar technology aimed at enhancing its performance to meet both landing and automated rendezvous and docking applications.

  10. Low Earth Orbit Rendezvous Strategy for Lunar Missions

    NASA Technical Reports Server (NTRS)

    Cates, Grant R.; Cirillo, William M.; Stromgren, Chel

    2006-01-01

    On January 14, 2004 President George W. Bush announced a new Vision for Space Exploration calling for NASA to return humans to the moon. In 2005 NASA decided to use a Low Earth Orbit (LEO) rendezvous strategy for the lunar missions. A Discrete Event Simulation (DES) based model of this strategy was constructed. Results of the model were then used for subsequent analysis to explore the ramifications of the LEO rendezvous strategy.

  11. Shuttle on-orbit rendezvous targeting: Circular orbits

    NASA Technical Reports Server (NTRS)

    Bentley, E. L.

    1972-01-01

    The strategy and logic used in a space shuttle on-orbit rendezvous targeting program are described. The program generates ascent targeting conditions for boost to insertion into an intermediate parking orbit, and generates on-orbit targeting and timeline bases for each maneuver to effect rendezvous with a space station. Time of launch is determined so as to eliminate any plane change, and all work was performed for a near-circular space station orbit.

  12. Automated rendezvous and capture system development and simulation for NASA

    NASA Astrophysics Data System (ADS)

    Roe, Fred D.; Howard, Richard T.; Murphy, Leslie

    2004-09-01

    The United States does not have an Automated Rendezvous and Capture/Docking (AR&C) capability and is reliant on manned control for rendezvous and docking of orbiting spacecraft. This reliance on the labor intensive manned interface for control of rendezvous and docking vehicles has a significant impact on the cost of the operation of the International Space Station (ISS) and precludes the use of any U.S. expendable launch capabilities for Space Station resupply. The Marshall Space Flight Center (MSFC) has conducted pioneering research in the development of an automated rendezvous and capture (or docking) (AR&C) system for U.S. space vehicles. This AR&C system was tested extensively using hardware-in-the-loop simulations in the Flight Robotics Laboratory, and a rendezvous sensor, the Video Guidance Sensor was developed and successfully flown on the Space Shuttle on flights STS-87 and STS-95, proving the concept of a video- based sensor. Further developments in sensor technology and vehicle and target configuration have lead to continued improvements and changes in AR&C system development and simulation. A new Advanced Video Guidance Sensor (AVGS) with target will be utilized as the primary navigation sensor on the Demonstration of Autonomous Rendezvous Technologies (DART) flight experiment in 2004. Realtime closed-loop simulations will be performed to validate the improved AR&C systems prior to flight.

  13. Automated Rendezvous and Capture System Development and Simulation for NASA

    NASA Technical Reports Server (NTRS)

    Roe, Fred D.; Howard, Richard T.; Murphy, Leslie

    2004-01-01

    The United States does not have an Automated Rendezvous and Capture Docking (AR&C) capability and is reliant on manned control for rendezvous and docking of orbiting spacecraft. T h i s reliance on the labor intensive manned interface for control of rendezvous and docking vehicles has a significant impact on the cost of the operation of the International Space Station (ISS) and precludes the use of any U.S. expendable launch capabilities for Space Station resupply. The Marshall Space Flight Center (MSFC) has conducted pioneering research in the development of an automated rendezvous and capture (or docking) (AR&C) system for U.S. space vehicles. This A M C system was tested extensively using hardware-in-the-loop simulations in the Flight Robotics Laboratory, and a rendezvous sensor, the Video Guidance Sensor was developed and successfully flown on the Space Shuttle on flights STS-87 and STS-95, proving the concept of a video- based sensor. Further developments in sensor technology and vehicle and target configuration have lead to continued improvements and changes in AR&C system development and simulation. A new Advanced Video Guidance Sensor (AVGS) with target will be utilized as the primary navigation sensor on the Demonstration of Autonomous Rendezvous Technologies (DART) flight experiment in 2004. Realtime closed-loop simulations will be performed to validate the improved AR&C systems prior to flight.

  14. Crossover from tumbling to tank-treading-like motion in dense simulated suspensions of red blood cells

    E-print Network

    Krüger, Timm; Raabe, Dierk; Varnik, Fathollah

    2013-01-01

    Via computer simulations, we provide evidence that the shear rate induced red blood cell tumbling-to-tank-treading transition also occurs at quite high volume fractions, where collective effects are important. The transition takes place as the ratio of suspension stress to the characteristic cell membrane stress exceeds a certain value, independent of volume fraction and cell deformability. This value coincides with that for a transition from an orientationally less ordered to a highly ordered phase. The average cell deformation does not show any signature of the transition, but rather follows a simple scaling law independent of volume fraction.

  15. Crossover from tumbling to tank-treading-like motion in dense simulated suspensions of red blood cells

    E-print Network

    Timm Krüger; Markus Gross; Dierk Raabe; Fathollah Varnik

    2013-12-12

    Via computer simulations, we provide evidence that the shear rate induced red blood cell tumbling-to-tank-treading transition also occurs at quite high volume fractions, where collective effects are important. The transition takes place as the ratio of suspension stress to the characteristic cell membrane stress exceeds a certain value, independent of volume fraction and cell deformability. This value coincides with that for a transition from an orientationally less ordered to a highly ordered phase. The average cell deformation does not show any signature of the transition, but rather follows a simple scaling law independent of volume fraction.

  16. Automated Rendezvous and Capture System Development and Simulation for NASA

    NASA Technical Reports Server (NTRS)

    Roe, Fred D.; Howard, Richard T.; Murphy, Leslie

    2004-01-01

    The United States does not have an Automated Rendezvous and Capture/Docking (AR and C) capability and is reliant on manned control for rendezvous and docking of orbiting spacecraft. This reliance on the labor intensive manned interface for control of rendezvous and docking vehicles has a significant impact on the cost of the operation of the International Space Station (ISS) and precludes the use of any U.S. expendable launch capabilities for Space Station resupply. The Soviets have the capability to autonomously dock in space, but their system produces a hard docking with excessive force and contact velocity. Automated Rendezvous and Capture/Docking has been identified as a key enabling technology for the Space Launch Initiative (SLI) Program, DARPA Orbital Express and other DOD Programs. The development and implementation of an AR&C capability can significantly enhance system flexibility, improve safety, and lower the cost of maintaining, supplying, and operating the International Space Station. The Marshall Space Flight Center (MSFC) has conducted pioneering research in the development of an automated rendezvous and capture (or docking) (AR and C) system for U.S. space vehicles. This AR&C system was tested extensively using hardware-in-the-loop simulations in the Flight Robotics Laboratory, and a rendezvous sensor, the Video Guidance Sensor was developed and successfully flown on the Space Shuttle on flights STS-87 and STS-95, proving the concept of a video- based sensor. Further developments in sensor technology and vehicle and target configuration have lead to continued improvements and changes in AR&C system development and simulation. A new Advanced Video Guidance Sensor (AVGS) with target will be utilized on the Demonstration of Autonomous Rendezvous Technologies (DART) flight experiment in 2004.

  17. The ion drive program - Comet rendezvous issues for SEPS developers

    NASA Technical Reports Server (NTRS)

    Atkins, K. L.

    1979-01-01

    Preliminary steps have been taken in a joint high-priority project between NASA and the European Space Agency, whereby a Solar Electric Propulsion System (SEPS), using ion drive of a 25-30 kilowatt power level, will be utilized for the first time, as part of the Space Transportation System, in powering a probe to be deployed toward Halley's comet in 1985 and a separate spacecraft which will rendezvous with the Temple 2 comet in 1988 and study it for one year. Unlike ballistically-launched vehicles, an unprecedented long-term interaction between the SEPS, the primary source of power and attitude control, and the spacecraft, responsible for data handling (at a rate of 10-120 kilobits per second), and command and telecommunications to earth (requiring capabilities at both X- and S-band frequencies, for dual-frequency navigational tracking), is required, as mission phases alternate between powered flight and science data-taking. Different design sensitivities are presented graphically.

  18. Liquid crystal Janus emulsion droplets: preparation, tumbling, and swimming.

    PubMed

    Jeong, Joonwoo; Gross, Adam; Wei, Wei-Shao; Tu, Fuquan; Lee, Daeyeon; Collings, Peter J; Yodh, A G

    2015-09-14

    This study introduces liquid crystal (LC) Janus droplets. We describe a process for the preparation of these droplets, which consist of nematic LC and polymer compartments. The process employs solvent-induced phase separation in emulsion droplets generated by microfluidics. The droplet morphology was systematically investigated and demonstrated to be sensitive to the surfactant concentration in the background phase, the compartment volume ratio, and the possible coalescence of multiple Janus droplets. Interestingly, the combination of a polymer and an anisotropic LC introduces new functionalities into Janus droplets, and these properties lead to unusual dynamical behaviors. The different densities and solubilities of the two compartments produce gravity-induced alignment, tumbling, and directional self-propelled motion of Janus droplets. LC Janus droplets with remarkable optical properties and dynamical behaviors thus offer new avenues for applications of Janus colloids and active soft matter. PMID:26171829

  19. Advanced Multipurpose Rendezvous Tracking System Study

    NASA Technical Reports Server (NTRS)

    Laurie, R. J.; Sterzer, F.

    1982-01-01

    Rendezvous and docking (R&D) sensors needed to support Earth orbital operations of vehicles were investigated to determine the form they should take. An R&D sensor must enable an interceptor vehicle to determine both the relative position and the relative attitude of a target vehicle. Relative position determination is fairly straightforward and places few constraints on the sensor. Relative attitude determination, however, is more difficult. The attitude is calculated based on relative position measurements of several reflectors placed in a known arrangement on the target vehicle. The constraints imposed on the sensor by the attitude determination method are severe. Narrow beamwidth, wide field of view (fov), high range accuracy, and fast random scan capability are all required to determine attitude by this method. A consideration of these constraints as well as others imposed by expected operating conditions and the available technology led to the conclusion that the sensor should be a cw optical radar employing a semiconductor laser transmitter and an image dissector receiver.

  20. Robot Acting on Moving Bodies (RAMBO): Interaction with tumbling objects

    NASA Technical Reports Server (NTRS)

    Davis, Larry S.; Dementhon, Daniel; Bestul, Thor; Ziavras, Sotirios; Srinivasan, H. V.; Siddalingaiah, Madhu; Harwood, David

    1989-01-01

    Interaction with tumbling objects will become more common as human activities in space expand. Attempting to interact with a large complex object translating and rotating in space, a human operator using only his visual and mental capacities may not be able to estimate the object motion, plan actions or control those actions. A robot system (RAMBO) equipped with a camera, which, given a sequence of simple tasks, can perform these tasks on a tumbling object, is being developed. RAMBO is given a complete geometric model of the object. A low level vision module extracts and groups characteristic features in images of the object. The positions of the object are determined in a sequence of images, and a motion estimate of the object is obtained. This motion estimate is used to plan trajectories of the robot tool to relative locations rearby the object sufficient for achieving the tasks. More specifically, low level vision uses parallel algorithms for image enhancement by symmetric nearest neighbor filtering, edge detection by local gradient operators, and corner extraction by sector filtering. The object pose estimation is a Hough transform method accumulating position hypotheses obtained by matching triples of image features (corners) to triples of model features. To maximize computing speed, the estimate of the position in space of a triple of features is obtained by decomposing its perspective view into a product of rotations and a scaled orthographic projection. This allows use of 2-D lookup tables at each stage of the decomposition. The position hypotheses for each possible match of model feature triples and image feature triples are calculated in parallel. Trajectory planning combines heuristic and dynamic programming techniques. Then trajectories are created using dynamic interpolations between initial and goal trajectories. All the parallel algorithms run on a Connection Machine CM-2 with 16K processors.

  1. Shape and trajectory of a tumbling elastic sheet of paper II

    NASA Astrophysics Data System (ADS)

    Tam, Daniel; Robitaille, Michael; Kudrolli, Arshad; Bush, John

    2009-03-01

    We investigate the dynamical coupling between the tumbling motion and elastic deformation of a paper strip freely falling in air. Recent experiments suggest the existence of a critical length above which the strip bends as it tumbles. We demonstrate that this bending is caused by the centripetal force associated with its tumbling motion. A simple theory predicts that bending occurs above a critical length in much the same way that buckling occurs in a compressed beam. We further discuss the influence of bending on the trajectory of paper strips, as well as biological implications for the dispersal of seed pods.

  2. A Monte-Carlo performance analysis of Kalman filter and targeting algorithms for autonomous orbital rendezvous

    E-print Network

    Vaughan, Andrew Thomas, 1979-

    2004-01-01

    Autonomous orbital rendezvous with an orbiting sample (OS) is seen as an enabling technology for a Mars Sample Return (MSR) mission, so several demonstrations have been planned. With CNES cooperation a proposed rendezvous ...

  3. Methodology for prototyping increased levels of automation for spacecraft rendezvous functions 

    E-print Network

    Hart, Jeremy Jay

    2009-05-15

    in Matlab using Fuzzy Logic (FL) techniques and existing Shuttle rendezvous trajectory algorithms. The prototyped functions are the determination of the maximum allowable Timeof- IGnition (TIG) slip for a rendezvous phasing burn and the evaluation of vehicle...

  4. Rendezvous and Proximity Operations of the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Goodman, John L.

    2005-01-01

    Space Shuttle rendezvous missions present unique challenges that were not fully recognized when the Shuttle was designed. Rendezvous targets could be passive (i.e., no lights or transponders), and not designed to facilitate Shuttle rendezvous, proximity operations, and retrieval. Shuttle reaction control system jet plume impingement on target spacecraft presented induced dynamics, structural loading, and contamination concerns. These issues, along with limited reaction control system propellant in the Shuttle nose, drove a change from the legacy Gemini/Apollo coelliptic profile to a stable orbit profile, and the development of new proximity operations techniques. Multiple scientific and on-orbit servicing missions, and crew exchange, assembly and replenishment flights to Mir and to the International Space Station drove further profile and piloting technique changes. These changes included new proximity operations, relative navigation sensors, and new computer generated piloting cues. However, the Shuttle's baseline rendezvous navigation system has not required modification to place the Shuttle at the proximity operations initiation point for all rendezvous missions flown.

  5. An autonomous rendezvous and docking system using cruise missile technologies

    NASA Astrophysics Data System (ADS)

    Jones, Ruel E.

    1992-03-01

    Using rapid prototyping techniques, the Autonomous Rendezvous Docking (ARD) system was evaluated in a real-time, hardware-in-the-loop simulation of the rendezvous and docking reference mission. The ARD system is also being upgraded to be able to test an Autonomous Approach and Landing system. A fully autonomous rendezvous and docking system based on the Centaur modern avionics suite in conjunction with cruise missile technology is considered to be very viable. The image processing system which includes a general-purpose multiprocessor computer and a selected suite of sensors provides the benefit of performing terrain matching and object recognition which makes it possible to use the same system for autonomous landing support.

  6. Rendezvous missions: From ISS to lunar space station

    NASA Astrophysics Data System (ADS)

    Murtazin, Rafail

    2014-08-01

    There was a lot of experience gained in the rendezvous of different vehicles in the LEO during the years of human space exploration. In the framework of the Apollo program when the astronauts landed on the surface of the Moon, the docking of the Lunar Module launched from the Moon's surface to the Apollo Command Module was successfully implemented in the near-Moon orbit. Presently many space agencies are considering a return to the Moon. It is necessary to solve the new task of docking the vehicle launched from the Earth to the long-term near-Moon orbital station taking into account specific constraints. Based on the ISS experience the author proposes a number of ballistic rendezvous strategies that provide for docking to the near-Moon orbital station with minimum propellant consumption. The trade-off analysis of the given rendezvous strategies is presented.

  7. Quantitative characterization of agglomerate abrasion in a tumbling blender by using the Stokes number approach.

    PubMed

    Willemsz, Tofan A; Nguyen, Tien Thanh; Hooijmaijers, Ricardo; Frijlink, Henderik W; Vromans, Herman; van der Voort Maarschalk, Kees

    2013-03-01

    Removal of microcrystalline cellulose agglomerates in a dry-mixing system (lactose, 100 M) predominantly occurs via abrasion. The agglomerate abrasion rate potential is estimated by the Stokes abrasion (StAbr) number of the system. The StAbr number equals the ratio between the kinetic energy density of the moving powder bed and the work of fracture of the agglomerate. Basically, the StAbr number concept describes the blending condition of the dry-mixing system. The concept has been applied to investigate the relevance of process parameters on agglomerate abrasion in tumbling blenders. Here, process parameters such as blender rotational speed and relative fill volumes were investigated. In this study, the StAbr approach revealed a transition point between abrasion rate behaviors. Below this transition point, a blending condition exists where agglomerate abrasion is dominated by the kinetic energy density of the powder blend. Above this transition point, a blending condition exists where agglomerates show (undesirable) slow abrasion rates. In this situation, the blending condition is mainly determined by the high fill volume of the filler. PMID:23250711

  8. Unsteady aerodynamic forces and torques on falling parallelograms in coupled tumbling-helical motions

    NASA Astrophysics Data System (ADS)

    Varshney, Kapil; Chang, Song; Wang, Z. Jane

    2013-05-01

    Falling parallelograms exhibit coupled motion of autogyration and tumbling, similar to the motion of falling tulip seeds, unlike maple seeds which autogyrate but do not tumble, or rectangular cards which tumble but do not gyrate. This coupled tumbling and autogyrating motion are robust, when card parameters, such as aspect ratio, internal angle, and mass density, are varied. We measure the three-dimensional (3D) falling kinematics of the parallelograms and quantify their descending speed, azimuthal rotation, tumbling rotation, and cone angle in each falling. The cone angle is insensitive to the variation of the card parameters, and the card tumbling axis does not overlap with but is close to the diagonal axis. In addition to this connection to the dynamics of falling seeds, these trajectories provide an ideal set of data to analyze 3D aerodynamic force and torque at an intermediate range of Reynolds numbers, and the results will be useful for constructing 3D aerodynamic force and torque models. Tracking these free falling trajectories gives us a nonintrusive method for deducing instantaneous aerodynamic forces. We determine the 3D aerodynamic forces and torques based on Newton-Euler equations. The dynamical analysis reveals that, although the angle of attack changes dramatically during tumbling, the aerodynamic forces have a weak dependence on the angle of attack. The aerodynamic lift is dominated by the coupling of translational and rotational velocities. The aerodynamic torque has an unexpectedly large component perpendicular to the card. The analysis of the Euler equation suggests that this large torque is related to the deviation of the tumbling axis from the principle axis of the card.

  9. Unsteady aerodynamic forces and torques on falling parallelograms in coupled tumbling-helical motions.

    PubMed

    Varshney, Kapil; Chang, Song; Wang, Z Jane

    2013-05-01

    Falling parallelograms exhibit coupled motion of autogyration and tumbling, similar to the motion of falling tulip seeds, unlike maple seeds which autogyrate but do not tumble, or rectangular cards which tumble but do not gyrate. This coupled tumbling and autogyrating motion are robust, when card parameters, such as aspect ratio, internal angle, and mass density, are varied. We measure the three-dimensional (3D) falling kinematics of the parallelograms and quantify their descending speed, azimuthal rotation, tumbling rotation, and cone angle in each falling. The cone angle is insensitive to the variation of the card parameters, and the card tumbling axis does not overlap with but is close to the diagonal axis. In addition to this connection to the dynamics of falling seeds, these trajectories provide an ideal set of data to analyze 3D aerodynamic force and torque at an intermediate range of Reynolds numbers, and the results will be useful for constructing 3D aerodynamic force and torque models. Tracking these free falling trajectories gives us a nonintrusive method for deducing instantaneous aerodynamic forces. We determine the 3D aerodynamic forces and torques based on Newton-Euler equations. The dynamical analysis reveals that, although the angle of attack changes dramatically during tumbling, the aerodynamic forces have a weak dependence on the angle of attack. The aerodynamic lift is dominated by the coupling of translational and rotational velocities. The aerodynamic torque has an unexpectedly large component perpendicular to the card. The analysis of the Euler equation suggests that this large torque is related to the deviation of the tumbling axis from the principle axis of the card. PMID:23767634

  10. Automatic rendezvous and capture system development in a manned environment

    NASA Technical Reports Server (NTRS)

    Kachmar, Peter M.; Jackson, William L.

    1991-01-01

    This paper presents the development of a 'Phase One' AR&C system capability as a logical outgrowth of Rendezvous and Proximity Operations (R&PO) system development for manned space programs. The continuity of the approach to R&PO across the Apollo, Skylab, Apollo-Soyuz, and Shuttle programs is traced and lessons learned which are applicable to AR&C discussed. Use of the Shuttle as a test bed for Automatic Rendezvous and Capture capabilities and technology demonstrations is discussed. A status of the current Phase One System design and brief overview of its capabilities is presented.

  11. Laser space rendezvous and docking system study continuation

    NASA Technical Reports Server (NTRS)

    Adelman, S.; Heynau, H.; Levinson, S.; Weindling, F.

    1977-01-01

    Investigations were made of a configuration for a spaceborne laser radar (ladar) to meet the requirements for rendezvous and docking with a cooperative object in synchronous orbit. An analysis was completed of laser phase locking techniques, while experimental verification was made of pulse repetition frequency and resonant scanning control loops. Data measurements on a satellite mock-up were also made. The investigation supports the original contention that a rendezvous and docking ladar can be configured to offer a cost effective and reliable solution to envisioned space missions.

  12. Joint certificate marking historical moment during ASTP rendezvous

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The hands of Cosmonaut Valerly N. Kubasov are seen as the ASTP engineer adds his name to the signature on the Soviet side of the Offical joint certificate marking an historical moment during rendezvous day of the Apollo-Soyuz Test Project. The left hand of Astronaut Donald K. Slayton, NASA's docking module pilot, is seen at left.

  13. Autonomous spacecraft executive and its application to rendezvous and docking

    NASA Technical Reports Server (NTRS)

    Komura, Fuminobu; Furuya, Masatoshi; Sasaki, Toshiro; Anderson, Robert L.; Tsugawa, Roy K.

    1994-01-01

    Autonomy is needed for future spacecraft to solve the problems of human operator overload and transmission delay. This paper describes the autonomous spacecraft executive for rendezvous and docking. It is an onboard expert system and has decision making capability for mission planning of nominal and contingency cases. The executive has been developed and verified using a hardware motion based simulator.

  14. Spectrum Sharing with Rotating Radar: Implications for Cognitive Radio Rendezvous

    E-print Network

    Buehrer, R. Michael

    Spectrum Sharing with Rotating Radar: Implications for Cognitive Radio Rendezvous Jeffrey D. Poston measurements of an actual radar system, this paper studies how an ad hoc network of cognitive radios lacking in time & frequency. Even prior work specifically on sharing with radar systems typically proposes

  15. Successful Development of an Automated Rendezvous and Capture System

    NASA Technical Reports Server (NTRS)

    Roe, Fred D.; Howard, Richard T.

    2002-01-01

    During the 1990's, the Marshall Space Flight Center (MSFC) conducted pioneering research in the development of an automated rendezvous and capture/docking system for U.S. space vehicles. Development and demonstration of a rendezvous sensor was identified early in the AR&C Program as the critical enabling technology that allows automated proximity operations and docking. A first generation rendezvous sensor, the Video Guidance Sensor (VGS) was developed and successfully flown on STS 87 and again on STS 95, proving the concept of a video-based sensor. Advances in both video and signal processing technologies and the lessons learned from the two successful flight experiments provided a baseline for the development, by the MSFC, of a new generation of video based rendezvous sensor. The Advanced Video Guidance Sensor (AVGS) has greatly increased performance and additional capability for longer-range operation with a new Target designed as a direct replacement for existing ISS hemispherical reflectors. A ground demonstration of the entire system and software was successfully tested.

  16. Autonomous rendezvous and feature detection system using TV imagery

    NASA Technical Reports Server (NTRS)

    Rice, R. B., Jr.

    1977-01-01

    Algorithms and equations are used for conversion of standard television imaging system information into directly usable spatial and dimensional information. System allows utilization of spacecraft imagery system as sensor in application to operations such as deriving spacecraft steering signal, tracking, autonomous rendezvous and docking and ranging.

  17. Autonomous Mars ascent and orbit rendezvous for earth return missions

    NASA Technical Reports Server (NTRS)

    Edwards, H. C.; Balmanno, W. F.; Cruz, Manuel I.; Ilgen, Marc R.

    1991-01-01

    The details of tha assessment of autonomous Mars ascent and orbit rendezvous for earth return missions are presented. Analyses addressing navigation system assessments, trajectory planning, targeting approaches, flight control guidance strategies, and performance sensitivities are included. Tradeoffs in the analysis and design process are discussed.

  18. Cooperative Relative Navigation for Space Rendezvous and Proximity Operations Using

    E-print Network

    Tsiotras, Panagiotis

    -based applications with limited range (e.g., ground robotics, augmented reality), and their performance deteCooperative Relative Navigation for Space Rendezvous and Proximity Operations Using Controlled operations using a monocular camera in a numerically efficient manner. It is assumed that the target

  19. Multiple Radios for Effective Rendezvous in Cognitive Radio Networks

    E-print Network

    Chu, Xiaowen

    Multiple Radios for Effective Rendezvous in Cognitive Radio Networks Lu Yu1 , Hai Liu1 , Yiu in cognitive radio networks (CRNs) for establishing a communication link on a commonly-available channel is equipped with one radio (i.e., one wireless transceiver). As the cost of wireless transceivers is dropping

  20. PERFORMANCE EVALUATION OF RENDEZVOUS USING MODEL PREDICTIVE CONTROL

    E-print Network

    PERFORMANCE EVALUATION OF RENDEZVOUS USING MODEL PREDICTIVE CONTROL Arthur Richards and Jonathan How ABSTRACT A new form of Model Predictive Control (MPC) is presented. It is shown to guarantee are present. INTRODUCTION This paper extends a recently-developed form of Model Predictive Control (MPC) [2

  1. Autonomous rendezvous and docking technologies: status and prospects

    NASA Astrophysics Data System (ADS)

    Wertz, James R.; Bell, Robert

    2003-08-01

    In general, autonomous rendezvous and docking requires that two spacecraft start at a remote distance (i.e., out of sight of each other), come together into a common orbit, rendezvous, dock, and control the new combined spacecraft in both orbit and attitude. Doing this requires developing and testing a variety of new technologies including absolute and relative autonomous navigation, autonomous rendezvous and docking hardware and software (both sensors and actuators), and autonomous control of a "new" spacecraft with different mass and inertia properties than either of the two original spacecraft. While these are very workable technologies, they do require a significant change in mindset -- turning over control of thrusters and other actuators to an on-board computer. While there is substantial potential for cost savings, risk reduction, and new mission modes by use of these technologies, there is a very strong reticence to allowing operational spacecraft to control their own destiny, particularly in firing thrusters. This paper summarizes work at Microcosm and elsewhere in each of the above technologies. Autonomous navigation and absolute orbit control have been demonstrated on orbit. In conjunction with Michigan Aerospace, autonomous rendezvous and docking hardware and algorithms have been demonstrated in parabolic flights and zero-g simulations. Approaches have been proposed for more precise and robust autonomous navigation and autonomous on-orbit estimation of combined mass and inertia properties, leading to efficient orbit and attitude control of the combined spacecraft. Many of these technologies can be tested at low cost in parabolic flights, suborbital flights, and evaluation of data from existing or planned missions. Thus, a "coordinated attack" on the complete problem of fully autonomous rendezvous and docking is both feasible and potentially very low cost.

  2. Dynamical properties of nematic liquid crystals subjected to shear flow and magnetic fields: Tumbling instability and nonequilibrium fluctuations

    NASA Astrophysics Data System (ADS)

    Fatriansyah, Jaka Fajar; Orihara, Hiroshi

    2013-07-01

    We investigate the dynamical properties of monodomain nematic liquid crystals under shear flow and magnetic fields on the basis of the Ericksen-Leslie theory. Stable and unstable states appear depending on the magnetic field and the shear rate. The trajectory of the unstable state shows tumbling motion. The phase diagram of these states is plotted as a function of the three components of the magnetic field at a constant shear rate. The phase diagram changes depending on the viscous properties of different types of nematic liquid crystals. In this nonequilibrium steady state, we calculate the correlation function of director fluctuations and the response function, and discuss the nonequilibrium fluctuations and the modified fluctuation-dissipation relation in connection with nonconservative forces due to shear flow.

  3. Enchanted rendezvous: John C. Houbolt and the genesis of the lunar-orbit rendezvous concept

    NASA Technical Reports Server (NTRS)

    Hansen, James R.

    1995-01-01

    This is the fourth publication of the 'Monographs in Aerospace History' series, prepared by the NASA History Office. These publications are intended to be tightly focused in terms of subject, relatively short in length, and reproduced to allow timely and broad dissemination to researchers in aerospace history. This publication details the arguments of John C. Houbolt, an engineer at the Langley Research Center in Hampton, Virginia, in his 1961-1962 campaign to support the lunar-orbit rendezvous (LOR). The LOR was eventually selected during Project Apollo as the method of flying to the Moon, landing on the surface, and returning to Earth. The LOR opted to send the entire lunar spacecraft up in one launch, enter into the lunar orbit, and dispatch a small lander to the lunar surface. It was the simplest of the various methods, both in terms of development and operational costs, but it was risky. There was no room for error or the crew could not get home; and the more difficult maneuvers had to be done when the spacecraft was committed to a circumlunar flight. Houbolt was one of the most vocal people supporting the LOR.

  4. A new approach for teleoperation rendezvous and docking with time delay

    NASA Astrophysics Data System (ADS)

    Zhou, JianYong; Jiang, ZiCheng; Tang, GuoJin

    2012-02-01

    Teleoperation rendezvous and docking can be used as a backup for autonomous rendezvous and docking (RVD) for an unmanned spacecraft or for guiding the chaser docking with an uncooperative target. The inherent teleoperation time delay is a rigorous problem, especially when the chaser is teleoperated on the ground. To eliminate the effect of time delay, a new approach for teleoperation RVD is studied. The characteristics of teleoperation RVD are analyzed by comparisons with the teleoperation robot and with manually controlled RVD; the relative motion of the chaser is predicted based on the C-W equation; and the processed measure information with time delay through the Kalman filter is utilized to correct the current prediction. Experimental results verify that the approach produces an 18% enhanced success rate of teleoperation RVD compared with direct visual feedback, and consumes less time and fuel. The developed approach also solves the time delay problem effectively. Teleoperation RVD using this method can be applied as a useful backup for autonomous RVD.

  5. Suppression of E. coli tumbling and wobbling in dilute polymeric fluids

    NASA Astrophysics Data System (ADS)

    Patteson, Alison; Gopinath, Arvind; Arratia, Paulo

    2015-03-01

    Bacteria commonly utilize a run-and-tumble swimming behavior to navigate through complex environments, such as mucus in the lungs or digestive system. This swimming behavior has been extensively studied in water-like fluids; yet, studies on the role of particles/polymers on the run-and-tumble technique are limited. Here, we experimentally investigate the role of polymer concentration on the swimming dynamics of E. coli. We find that small amounts of polymer drastically change the run-and-tumble behavior of E. coli cells, significantly enhancing the translational diffusion. The average cell velocity increases with polymer concentration (and viscosity) and the mean run times are enhanced. By varying polymer molecular weight, we show that enhanced translation is a result of two mechanisms: (1) suppression of cell wobbling due to elasticity and (2) enhancement of run times due to viscosity. Our results show that the transport of chemotactic cells can be independently modified by viscosity and elasticity.

  6. Effect of Different Tumbling Marination Treatments on the Quality Characteristics of Prepared Pork Chops

    PubMed Central

    Gao, Tian; Li, Jiaolong; Zhang, Lin; Jiang, Yun; Ma, Ruixue; Song, Lei; Gao, Feng; Zhou, Guanghong

    2015-01-01

    The effect of different tumbling marination treatments (control group, CG; conventional static marination, SM; vacuum continuous tumbling marination, CT; vacuum intermittent tumbling marination, IT) on the quality characteristics of prepared pork chops was investigated under simulated commercial conditions. The CT treatment increased (p<0.05) the pH value, b* value, product yield, tenderness, overall flavor, sensory juiciness and overall acceptability in comparison to other treatments for prepared boneless pork chops. The CT treatment decreased (p<0.05) cooking loss, shear force value, hardness, gumminess and chewiness compared with other treatments. In addition, CT treatment effectively improved springiness and sensory color more than other treatments. However, IT treatment achieved the numerically highest (p<0.05) L* and a* values. These results suggested that CT treatment obtained the best quality characteristics of prepared pork chops and should be adopted as the optimal commercial processing method for this prepared boneless pork chops. PMID:25557823

  7. Genetic algorithm based fuzzy control of spacecraft autonomous rendezvous

    NASA Technical Reports Server (NTRS)

    Karr, C. L.; Freeman, L. M.; Meredith, D. L.

    1990-01-01

    The U.S. Bureau of Mines is currently investigating ways to combine the control capabilities of fuzzy logic with the learning capabilities of genetic algorithms. Fuzzy logic allows for the uncertainty inherent in most control problems to be incorporated into conventional expert systems. Although fuzzy logic based expert systems have been used successfully for controlling a number of physical systems, the selection of acceptable fuzzy membership functions has generally been a subjective decision. High performance fuzzy membership functions for a fuzzy logic controller that manipulates a mathematical model simulating the autonomous rendezvous of spacecraft are learned using a genetic algorithm, a search technique based on the mechanics of natural genetics. The membership functions learned by the genetic algorithm provide for a more efficient fuzzy logic controller than membership functions selected by the authors for the rendezvous problem. Thus, genetic algorithms are potentially an effective and structured approach for learning fuzzy membership functions.

  8. Rendezvous and Proximity Operations of the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Goodman, John L.

    2005-01-01

    Space Shuttle rendezous missions presented unique challenges that were not fully recognized when the Shuttle was designed. Rendezvous targets could be passive (i.e., no lights or transponders), and not designed to facilitate Shuttle rendezvous, proximity operations and retrieval. Shuttle reaction control system jet plume impingement on target spacecraft presented induced dynamics, structural loading and contamination concerns. These issues, along with limited forward reaction control system propellant, drove a change from the Gemimi/Apollo coelliptic profile heritage to a stable orbit profile, and the development of new proximity operations techniques. Multiple scientific and on-orbit servicing missions and crew exchange, assembly and replinishment flights to Mir and to the International Space Station drove further profile and piloting technique changes, including new relative navigation sensors and new computer generated piloting cues.

  9. Space Debris Attitude Simulation - IOTA (In-Orbit Tumbling Analysis)

    NASA Astrophysics Data System (ADS)

    Kanzler, R.; Schildknecht, T.; Lips, T.; Fritsche, B.; Silha, J.; Krag, H.

    Today, there is little knowledge on the attitude state of decommissioned intact objects in Earth orbit. Observational means have advanced in the past years, but are still limited with respect to an accurate estimate of motion vector orientations and magnitude. Especially for the preparation of Active Debris Removal (ADR) missions as planned by ESA's Clean Space initiative or contingency scenarios for ESA spacecraft like ENVISAT, such knowledge is needed. The In-Orbit Tumbling Analysis tool (IOTA) is a prototype software, currently in development within the framework of ESA's “Debris Attitude Motion Measurements and Modelling” project (ESA Contract No. 40000112447), which is led by the Astronomical Institute of the University of Bern (AIUB). The project goal is to achieve a good understanding of the attitude evolution and the considerable internal and external effects which occur. To characterize the attitude state of selected targets in LEO and GTO, multiple observation methods are combined. Optical observations are carried out by AIUB, Satellite Laser Ranging (SLR) is performed by the Space Research Institute of the Austrian Academy of Sciences (IWF) and radar measurements and signal level determination are provided by the Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR). Developed by Hyperschall Technologie Göttingen GmbH (HTG), IOTA will be a highly modular software tool to perform short- (days), medium- (months) and long-term (years) propagation of the orbit and attitude motion (six degrees-of-freedom) of spacecraft in Earth orbit. The simulation takes into account all relevant acting forces and torques, including aerodynamic drag, solar radiation pressure, gravitational influences of Earth, Sun and Moon, eddy current damping, impulse and momentum transfer from space debris or micro meteoroid impact, as well as the optional definition of particular spacecraft specific influences like tank sloshing, reaction wheel behaviour, magnetic torquer activity and thruster firing. The meaning of IOTA is to provide high accuracy short-term simulations to support observers and potential ADR missions, as well as medium- and long-term simulations to study the significance of the particular internal and external influences on the attitude, especially damping factors and momentum transfer. The simulation will also enable the investigation of the altitude dependency of the particular external influences. IOTA's post-processing modules will generate synthetic measurements for observers and for software validation. The validation of the software will be done by cross-calibration with observations and measurements acquired by the project partners.

  10. Emergent Run-and-Tumble Behavior in a Simple Model of Chlamydomonas with Intrinsic Noise

    NASA Astrophysics Data System (ADS)

    Bennett, Rachel R.; Golestanian, Ramin

    2013-04-01

    Recent experiments on the green alga Chlamydomonas that swims using synchronized beating of a pair of flagella have revealed that it exhibits a run-and-tumble behavior similar to that of bacteria such as E. coli. Using a simple purely hydrodynamic model that incorporates a stroke cycle and an intrinsic Gaussian white noise, we show that a stochastic run-and-tumble behavior could emerge due to the nonlinearity of the combined synchronization-rotation-translation dynamics. Our study suggests that nonlinear mechanics could be a significant contributing factor to how the trajectories of the microorganism are selected.

  11. Active Brownian and Run-and-Tumble particles: A comparison of the large scale dynamics

    NASA Astrophysics Data System (ADS)

    Hancock, Benjamin; Baskaran, Aparna

    2015-03-01

    Active Brownian particles, such as self phoretic colloids, are a class of self propelled particles which swim at fixed speed with orientation that gradually changes through rotational diffusion. Some bacteria obey Run-and-Tumble dynamics, in which particles swim along a fixed orientation until a tumble event occurs that randomly selects a new orientation. At long time and length scales the diffusive-drift limit of the above dynamics appear to be identical. In this large scale limit, we study the effects of external fields on the dynamical properties of these two classes of self propelled particles.

  12. Fiber laser-based scanning lidar for space rendezvous and docking.

    PubMed

    Luo, Yuan; He, Yan; Gao, Min; Zhou, Cuiyun; Zang, Huaguo; Lei, Linjun; Xie, Kedi; Yang, Yan; Shi, Wei; Hou, Xia; Chen, Weibiao

    2015-03-20

    Lidar systems have played an important role in space rendezvous and docking (RVD). A new type of scanning lidar is developed using a high-repetition-rate pulsed fiber laser and a position detector. It will be a candidate for autonomous space RVD between two spacecrafts. The lidar can search and track cooperative targets in a large region without artificial guidance. The lidar's operational range spans from 18 m to 20 km, and the relative angle between two aircrafts can be measured with high accuracy. A novel fiber laser with tunable pulse energy and repetition rate is developed to meet the wide dynamic detection range of the lidar. This paper presents the lidar system's composition, performance, and experimental results in detail. PMID:25968536

  13. Autonomous rendezvous, docking, and landing system using cruise missile technologies

    NASA Astrophysics Data System (ADS)

    Jones, Ruel E.

    1992-07-01

    General Dynamics has been developing an Autonomous Rendezvous Docking and Landing (ARD&L) system that utilizes cruise missile technologies. In November 1990 the Autonomous Rendezvous and Docking (AR&D) system was first demonstrated for members of NASA's Strategic Avionics Technology Working Group (SATWG). This simulation utilized prototype hardware from the Cruise Missile and Advanced Centaur Avionics systems. The objective was to show that all the accuracy, reliability, and operational requirements established for a spacecraft to dock with Space Station Freedom could be met by the proposed system. Rapid prototyping techniques were used to evaluate the proposed system in a real time, hardware in the loop simulation of the rendezvous and docking reference mission. The simulation is currently being upgraded to test an Autonomous Approach and Landing (AA&L) system. Both systems use inertial guidance and control systems supplemented by the Global Positioning System (GPS) and an Image Processing System (IPS), for target recognition and tracking. The IPS includes a general purpose multiprocessor computer and a selected suite of sensors that will provide the required relative position and orientation data. Graphic displays can provide the astronaut/operator with realtime guidance and navigation data with enhanced video or sensor imagery.

  14. Supervised autonomous rendezvous and docking system technology evaluation

    NASA Technical Reports Server (NTRS)

    Marzwell, Neville I.

    1991-01-01

    Technology for manned space flight is mature and has an extensive history of the use of man-in-the-loop rendezvous and docking, but there is no history of automated rendezvous and docking. Sensors exist that can operate in the space environment. The Shuttle radar can be used for ranges down to 30 meters, Japan and France are developing laser rangers, and considerable work is going on in the U.S. However, there is a need to validate a flight qualified sensor for the range of 30 meters to contact. The number of targets and illumination patterns should be minimized to reduce operation constraints with one or more sensors integrated into a robust system for autonomous operation. To achieve system redundancy, it is worthwhile to follow a parallel development of qualifying and extending the range of the 0-12 meter MSFC sensor and to simultaneously qualify the 0-30(+) meter JPL laser ranging system as an additional sensor with overlapping capabilities. Such an approach offers a redundant sensor suite for autonomous rendezvous and docking. The development should include the optimization of integrated sensory systems, packaging, mission envelopes, and computer image processing to mimic brain perception and real-time response. The benefits of the Global Positioning System in providing real-time positioning data of high accuracy must be incorporated into the design. The use of GPS-derived attitude data should be investigated further and validated.

  15. Relative navigation requirements for automatic rendezvous and capture systems

    NASA Technical Reports Server (NTRS)

    Kachmar, Peter M.; Polutchko, Robert J.; Chu, William; Montez, Moises

    1991-01-01

    This paper will discuss in detail the relative navigation system requirements and sensor trade-offs for Automatic Rendezvous and Capture. Rendezvous navigation filter development will be discussed in the context of navigation performance requirements for a 'Phase One' AR&C system capability. Navigation system architectures and the resulting relative navigation performance for both cooperative and uncooperative target vehicles will be assessed. Relative navigation performance using rendezvous radar, star tracker, radiometric, laser and GPS navigation sensors during appropriate phases of the trajectory will be presented. The effect of relative navigation performance on the Integrated AR&C system performance will be addressed. Linear covariance and deterministic simulation results will be used. Evaluation of relative navigation and IGN&C system performance for several representative relative approach profiles will be presented in order to demonstrate the full range of system capabilities. A summary of the sensor requirements and recommendations for AR&C system capabilities for several programs requiring AR&C will be presented.

  16. Fast solar sail rendezvous mission to near Earth asteroids

    NASA Astrophysics Data System (ADS)

    Zeng, Xiangyuan; Gong, Shengping; Li, Junfeng

    2014-12-01

    The concept of fast solar sail rendezvous missions to near Earth asteroids is presented by considering the hyperbolic launch excess velocity as a design parameter. After introducing an initial constraint on the hyperbolic excess velocity, a time optimal control framework is derived and solved by using an indirect method. The coplanar circular orbit rendezvous scenario is investigated first to evaluate the variational trend of the transfer time with respect to different hyperbolic excess velocities and solar sail characteristic accelerations. The influence of the asteroid orbital inclination and eccentricity on the transfer time is studied in a parametric way. The optimal direction and magnitude of the hyperbolic excess velocity are identified via numerical simulations. The found results for coplanar circular scenarios are compared in terms of fuel consumption to the corresponding bi-impulsive transfer of the same flight time, but without using a solar sail. The fuel consumption tradeoff between the required hyperbolic excess velocity and the achievable flight time is discussed. The required total launch mass for a particular solar sail is derived in analytical form. A practical mission application is proposed to rendezvous with the asteroid 99942 Apophis by using a solar sail in combination with the provided hyperbolic excess velocity.

  17. Trajectory Control of Rendezvous with Maneuver Target Spacecraft

    NASA Technical Reports Server (NTRS)

    Zhou, Zhinqiang

    2012-01-01

    In this paper, a nonlinear trajectory control algorithm of rendezvous with maneuvering target spacecraft is presented. The disturbance forces on the chaser and target spacecraft and the thrust forces on the chaser spacecraft are considered in the analysis. The control algorithm developed in this paper uses the relative distance and relative velocity between the target and chaser spacecraft as the inputs. A general formula of reference relative trajectory of the chaser spacecraft to the target spacecraft is developed and applied to four different proximity maneuvers, which are in-track circling, cross-track circling, in-track spiral rendezvous and cross-track spiral rendezvous. The closed-loop differential equations of the proximity relative motion with the control algorithm are derived. It is proven in the paper that the tracking errors between the commanded relative trajectory and the actual relative trajectory are bounded within a constant region determined by the control gains. The prediction of the tracking errors is obtained. Design examples are provided to show the implementation of the control algorithm. The simulation results show that the actual relative trajectory tracks the commanded relative trajectory tightly. The predicted tracking errors match those calculated in the simulation results. The control algorithm developed in this paper can also be applied to interception of maneuver target spacecraft and relative trajectory control of spacecraft formation flying.

  18. Quality characteristics of a dry-cured lamb leg as affected by tumbling after dry-salting and processing time.

    PubMed

    Villalobos-Delgado, Luz H; Caro, Irma; Blanco, Carolina; Morán, Lara; Prieto, Nuria; Bodas, Raul; Giráldez, Francisco J; Mateo, Javier

    2014-05-01

    The aim of this study was to evaluate selected quality characteristics of a dry-cured lamb leg with different tumbling treatments after salting. The characteristics were measured at different processing times. Three batches of dry-cured lamb legs (nine legs per batch) were prepared with no-, short- and long-tumbling treatments, and microbial counts, NaCl, aw, proximate composition, pH, free fatty acids, water soluble nitrogen, volatile compounds, texture and colour were evaluated at days 1, 22 and 71 of processing. Furthermore, a descriptive sensory analysis (flavour and texture) was performed in the final product (day 71). Time-related changes were observed for most of the characteristics studied. The effect of tumbling was only observed for the sensory attribute pastiness that was higher in tumbled legs. Methyl-branched butanal was only detected in tumbled legs. PMID:24553493

  19. Apollo experience report: Evolution of the rendezvous-maneuver plan for the lunar-landing missions

    NASA Technical Reports Server (NTRS)

    Alexander, J. D.; Becker, R. W.

    1973-01-01

    The evolution of the nominal rendezvous-maneuver plan for the lunar landing missions is presented along with a summary of the significant development for the lunar module abort and rescue plan. A general discussion of the rendezvous dispersion analysis that was conducted in support of both the nominal and contingency rendezvous planning is included. Emphasis is placed on the technical developments from the early 1960's through the Apollo 15 mission (July to August 1971), but pertinent organizational factors also are discussed briefly. Recommendations for rendezvous planning for future programs relative to Apollo experience also are included.

  20. Chaotic mixing of granular materials in two-dimensional tumbling mixers D. V. Khakhar,a)

    E-print Network

    Gilchrist, James F.

    the mixing of similar, cohesionless granular materials in quasi-two-dimensional rotating containers by means with model predictions. Studies of mixing are presented for circular, elliptical, and square containers in comparison with fluid mixing. We consider the mixing in two-dimensional tumbling mixers with a view to reveal

  1. Rough and Tumble Play Quality: Theoretical Foundations for a New Measure of Father-Child Interaction

    ERIC Educational Resources Information Center

    Fletcher, Richard; StGeorge, Jennifer; Freeman, Emily

    2013-01-01

    Energetic, competitive, body-contact play (rough and tumble play (RTP)) is commonly observed among young children and is reported as an important feature of father-child relationships. Animal studies have demonstrated positive developmental effects of peer-peer play-wrestling, influencing cognitive and social outcomes. The purpose of this paper is…

  2. 75 FR 35751 - Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Tumbling Creek...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-23

    ... on August 14, 2002 (67 FR 52879), and the Tumbling Creek Cavesnail Recovery Plan (published in the Federal Register on September 22, 2003 (68 FR 55060)), available on the Internet at http://ecos.fws.gov... on December 27, 2001 (66 FR 66803) and subsequently listed as endangered on August 14, 2002 (67...

  3. Simulation of collective behaviour in micro-scale swimmers: Effects of tumbling and rotary diffusion

    NASA Astrophysics Data System (ADS)

    Krishnamurthy, Deepak; Subramanian, Ganesh

    2013-11-01

    Recent experiments have shown that suspensions of swimming micro-organisms are characterized by complex dynamics involving enhanced swimming speeds, large-scale correlated motions and enhanced tracer diffusion. Understanding this dynamics is of fundamental interest and also has relevance to biological systems. In this work we develop a particle-based computational model to study a suspension of hydrodynamically interacting rod-like swimmers with the relation between the swimming velocity and intrinsic stress being enforced from slender body theory. Such an a priori specification reduces the computational cost since one now has a ``kinematic'' simulation with a fixed interaction law between swimmers; this does not restrict our study of the dynamics since the destabilizing mechanism has been attributed to the intrinsic (rather than the induced) stress field. Importantly, the model will include intrinsic de-correlation mechanisms found in bacteria such as rotary diffusion and tumbling whose effects have so far not been studied via simulations. Using this model we predict a box-size independent stability threshold based on the suspension concentration, tumble-time (duration between subsequent tumble events) and rotary diffusivity. Comparisons are made with the linear stability theory predictions by Subramanian & Koch (JFM 2009). We demonstrate that the effect of tumbling and rotary diffusion is to stabilize the suspension.

  4. Preschool Teachers' Perceptions of Rough and Tumble Play vs. Aggression in Preschool-Aged Boys

    ERIC Educational Resources Information Center

    DiCarlo, Cynthia F.; Baumgartner, Jennifer; Ota, Carrie; Jenkins, Charlene

    2015-01-01

    Rough and tumble play has been found to be positive for physical, social and cognitive development; it is often erroneously misinterpreted as aggression and generally stopped by preschool teachers. The current study sought to examine the relationship between teacher training and education and judgements about aggression in children. Ninety-four…

  5. Hydrodynamic model of bacterial tumbling near a non-slip surface

    NASA Astrophysics Data System (ADS)

    Sheng, Jian; Molaei, Mehdi

    2013-11-01

    To swim forward, wild type Escherichia coli bacteria rotate their helical flagella CCW to form a bundle; to tumble, one or more flagella rotate CW to initiate flagella unbundling and polymorphic transformation that leads to a significant change in cell orientation in comparison to original swimming direction. These random change of direction increases bacterial dispersion and also is long speculated to be a mechanism for perichtricous bacteria to escape from a surface. Our recent experimental results show that the tumbling frequency is substantially suppressed near a solid surface by 50%, and the bacterium tends to start a new run in the direction parallel to the surface. This suppression occurs at two cell length (including flagella) away from the surface whereby steric hindrance plays less significant role. Here we propose an analytical model based on hydrodynamic interaction between flagella and the solid surface. We utilize Slender Body Theory combined with the image system of the singularities for the Stoke-flow to quantify the flow around the bacterial flagella in the presence of a no-slip surface. The model includes two non-identical rigid helical flagella representing a bundle and single flagellum. We have showed that in the bulk, a repulsive force among flagella initiates the unbundling and consequently tumbling; however, in presence of a solid surface, the force is strongly mitigated that stabilize the bundle and suppress the tumbling. NIH, NSF, GoMRI.

  6. Is Father-Child Rough-and-Tumble Play Associated with Attachment or Activation Relationships?

    ERIC Educational Resources Information Center

    Paquette, Daniel; Dumont, Caroline

    2013-01-01

    The activation relationship theory, primarily focused on parental stimulation of risk-taking along with parental control during exploration, predicts that boys will be activated more than girls by their fathers. This theory may explain why fathers engage in rough-and-tumble play (RTP) with children more frequently than mothers, especially with…

  7. RIGID BODY INERTIA ESTIMATION WITH APPLICATIONS TO THE CAPTURE OF A TUMBLING SATELLITE

    E-print Network

    SATELLITE Daniel Sheinfeld* and Stephen Rock A framework for rigid-body inertia estimation is presented-free motion. It is applied here to the case of a tumbling satellite. In- cluded are a geometric interpretation that must be addressed to enable on-orbit servicing of satellites is how to cap- ture and de

  8. Tumbling Dynamics of Passive Flexible Wings Daniel Tam* and John W. M. Bush

    E-print Network

    Bush, John W.M.

    a rectangular wing of uniform thickness h, width w, cross-sectional area A Ľ wh, length L, density s, bending kg m2 sŔ2 , respectively. Paper wings of mod- erate to high aspect ratio, L=w Ľ 3­30, were usedTumbling Dynamics of Passive Flexible Wings Daniel Tam* and John W. M. Bush Department

  9. OPTIMAL DESPIN OF A TUMBLING SATELLITE WITH AN ARBITRARY THRUSTER CONFIGURATION, INERTIA MATRIX,

    E-print Network

    of the satellite, h, to zero by applying external forces and torques while minimizing some cost func- tional (fuel, AND COST FUNCTIONAL Daniel Sheinfeld* and Stephen Rock An algorithm to calculate the optimal control to despin a tumbling satellite with known, but arbitrary thruster configuration, inertia matrix, and cost

  10. Rendezvous and docking (RVD) long range RF sensor definition study, executive summary

    NASA Astrophysics Data System (ADS)

    A 90 GHz radar, an S-band lobe switching sensor, and S-band phase switching sensors were compared for use as rendezvous and docking long range sensor aboard the chaser satellite. The lobe switching concept best meets requirements of target satellite acquisition (at a range of the order of 100 km) and operation at a range less than 100 m; measurement of relative distance (between chaser and target) with accuracy of 1 m (at short range); measurement of relative velocity (between chaser and target) with accuracy of 1 cm/sec (at short range); measurement of relative position (between chaser and target) expressed as bearing angles with respect to reference frame in the chaser, with accuracy of 0.5 deg in the field of view of +/- 30 deg; and measurement of bearing angle rates with respect to the reference frame in the chaser with accuracy of 0.05 deg/sec.

  11. Effect of Different Tumbling Marination Methods and Time on the Water Status and Protein Properties of Prepared Pork Chops

    PubMed Central

    Gao, Tian; Li, Jiaolong; Zhang, Lin; Jiang, Yun; Yin, Maowen; Liu, Yang; Gao, Feng; Zhou, Guanghong

    2015-01-01

    The combined effect of tumbling marination methods (vacuum continuous tumbling marination, CT; vacuum intermittent tumbling marination, IT) and effective tumbling time (4, 6, 8, and 10 h) on the water status and protein properties of prepared pork chops was investigated. Results showed that regardless of tumbling time, CT method significantly decreased the muscle fiber diameter (MD) and significantly increased the total moisture content, product yield, salt soluble proteins (SSP) solubility, immobilized water component (p<0.05) compared with IT method. With the effective tumbling time increased from 4 h to 10 h, the fat content and the MD were significantly decreased (p<0.05), whereas the SSP solubility of prepared pork chops increased firstly and then decreased. Besides, an interactive effect between CT method and effective tumbling time was also observed for the chemical composition and proportion of immobilized water (p<0.05). These results demonstrated that CT method of 8 h was the most beneficial for improving the muscle structure and water distribution status, increasing the water-binding capacity and accelerating the marinade efficiency of pork chops; and thus, it should be chosen as the most optimal treatment method for the processing production of prepared pork chops. PMID:26104408

  12. CHARACTERIZATION OF DISTURBANCES IN THE SPACE ENVIRONMENT FOR AUTONOMOUS CLOSE-RANGE RENDEZVOUS OF COOPERATIVE ROBOTS

    E-print Network

    Wiens, Gloria J.

    will be based on the Artificial Potential Function Guidance (APFG)6 . II. SYSTEM DYNAMICS Each vehicle for the vehicle performing the services (chaser) to rendezvous with the vehicle being serviced (target fundamental disturbances will be included: J2 effects and aerodynamic drag. The rendezvous controller tested

  13. Multiple Agents RendezVous In a Ring in Spite of a Black Hole

    E-print Network

    Flocchini, Paola

    Multiple Agents RendezVous In a Ring in Spite of a Black Hole Stefan Dobrev1 , Paola Flocchini1 there is a black hole: a stationary process located at a node that destroys any incoming agent without leaving any trace. The presence of the black hole makes it clearly impossible for all agents to rendezvous. So

  14. Modified rendezvous intrahepatic bile duct cannulation technique to pass a PTBD catheter in ERCP

    PubMed Central

    Lee, Tae Hoon; Park, Sang-Heum; Lee, Sae Hwan; Lee, Chang-Kyun; Lee, Suck-Ho; Chung, Il-Kwun; Kim, Hong Soo; Kim, Sun-Joo

    2010-01-01

    The rendezvous procedure combines an endoscopic technique with percutaneous transhepatic biliary drainage (PTBD). When a selective common bile duct cannulation fails, PTBD allows successful drainage and retrograde access for subsequent rendezvous techniques. Traditionally, rendezvous procedures such as the PTBD-assisted over-the-wire cannulation method, or the parallel cannulation technique, may be available when a bile duct cannot be selectively cannulated. When selective intrahepatic bile duct (IHD) cannulation fails, this modified rendezvous technique may be a feasible alternative. We report the case of a modified rendezvous technique, in which the guidewire was retrogradely passed into the IHD through the C2 catheter after end-to-end contact between the tips of the sphincterotome and the C2 catheter at the ampulla’s orifice, in a 39-year-old man who had been diagnosed with gallbladder carcinoma with a metastatic right IHD obstruction. Clinically this procedure may be a feasible and timesaving technique. PMID:21072905

  15. Comparative flight strategies for ascent from Martian surface to orbiter rendezvous

    NASA Technical Reports Server (NTRS)

    Menees, Gene P.; Wilson, John F.; Adelman, Henry G.

    1989-01-01

    Flight maneuvers and strategies to transport a vehicle from the Martian surface to orbiter rendezvous are analyzed to determine the most fuel-efficient method. Both endo- and exo-atmospheric flight strategies are considered for orbiter rendezvous into parking orbits of arbitrary inclination. It is found that optimal mass efficiency is achieved where the orbiter inclination is equal to or exceeds the latitude of the launch site. It is shown that high aerodynamic lifting capability improves performance for low circular orbit (LCO) rendezvous. It is suggested that the synergetic ballistic-projecting technique is best for optimal LCO rendezvous and that the all-thrust technique with plane change at apoapsis is best for optimal high elliptical orbit rendezvous.

  16. Optimal rendezvous in the neighborhood of a circular orbit

    NASA Technical Reports Server (NTRS)

    Jones, J. B.

    1976-01-01

    The minimum velocity-change rendezvous solutions, when the motion may be linearized about a circular orbit, fall into two separate regions; the phase-for-free region and the general region. Phase-for-free solutions are derived from the optimum transfer solutions, require the same velocity-change expenditure, but may not be unique. Analytic solutions are presented in two of the three subregions. An algorithm is presented for determining the unique solutions in the general region. Various sources of initial conditions are discussed and three examples are presented.

  17. Optimal rendezvous in the neighborhood of a circular orbit

    NASA Technical Reports Server (NTRS)

    Jones, J. B.

    1975-01-01

    The minimum velocity change rendezvous solutions, when the motion may be linearized about a circular orbit, fall into two separate regions; the phase-for-free region and the general region. Phase-for-free solutions are derived from the optimum transfer solutions, require the same velocity change expenditure, but may not be unique. Analytic solutions are presented in two of the three subregions. An algorithm is presented for determining the unique solutions in the general region. Various sources of initial conditions are discussed and three examples presented.

  18. Guidance laws for spacecraft pursuit-evasion and rendezvous

    NASA Astrophysics Data System (ADS)

    Menon, P. K. A.; Calise, A. J.; Leung, S. K. M.

    Nonlinear feedback guidance laws are developed for a pursuit-evasion differential game between two spacecraft, and for the more traditional spacecraft rendezvous problem using the complete nonlinear point-mass models. These guidance laws are suitable for on-board implementation. They are applicable for large amplitude maneuvers and can account for the presence of more than one gravitational field. An exact method for computing time-to-go required in guidance law implementation is developed. The guidance law performance is demonstrated using a three-degree-of-freedom simulation with a six harmonic gravitational model.

  19. Virtual reality applications to automated rendezvous and capture

    NASA Technical Reports Server (NTRS)

    Hale, Joseph; Oneil, Daniel

    1991-01-01

    Virtual Reality (VR) is a rapidly developing Human/Computer Interface (HCI) technology. The evolution of high-speed graphics processors and development of specialized anthropomorphic user interface devices, that more fully involve the human senses, have enabled VR technology. Recently, the maturity of this technology has reached a level where it can be used as a tool in a variety of applications. This paper provides an overview of: VR technology, VR activities at Marshall Space Flight Center (MSFC), applications of VR to Automated Rendezvous and Capture (AR&C), and identifies areas of VR technology that requires further development.

  20. Reference equations of motion for automatic rendezvous and capture

    NASA Technical Reports Server (NTRS)

    Henderson, David M.

    1992-01-01

    The analysis presented in this paper defines the reference coordinate frames, equations of motion, and control parameters necessary to model the relative motion and attitude of spacecraft in close proximity with another space system during the Automatic Rendezvous and Capture phase of an on-orbit operation. The relative docking port target position vector and the attitude control matrix are defined based upon an arbitrary spacecraft design. These translation and rotation control parameters could be used to drive the error signal input to the vehicle flight control system. Measurements for these control parameters would become the bases for an autopilot or feedback control system (FCS) design for a specific spacecraft.

  1. Universal Lambert and Kepler algorithms for autonomous rendezvous

    NASA Technical Reports Server (NTRS)

    Klumpp, Allan R.

    1990-01-01

    This paper describes Lambert and Kepler algorithms designed to be the core of an autonomous rendezvous guidance system for an onboard computer. Applications include robotic and piloted missions to the moon and planets. Flight software must be compact, fast, and totally reliable. Although high accuracy is not essential for flight, in double precision these algorithms are accurate to at least 14 places almost everywhere. Both are universal; they apply to elliptic, parabolic, hyperbolic, and even rectilinear trajectories. The algorithms are improvements to those published by Battin (1987).

  2. Determination of Eros Physical Parameters for Near Earth Asteroid Rendezvous Orbit Phase Navigation

    NASA Technical Reports Server (NTRS)

    Miller, J. K.; Antreasian, P. J.; Georgini, J.; Owen, W. M.; Williams, B. G.; Yeomans, D. K.

    1995-01-01

    Navigation of the orbit phase of the Near Earth steroid Rendezvous (NEAR) mission will re,quire determination of certain physical parameters describing the size, shape, gravity field, attitude and inertial properties of Eros. Prior to launch, little was known about Eros except for its orbit which could be determined with high precision from ground based telescope observations. Radar bounce and light curve data provided a rough estimate of Eros shape and a fairly good estimate of the pole, prime meridian and spin rate. However, the determination of the NEAR spacecraft orbit requires a high precision model of Eros's physical parameters and the ground based data provides only marginal a priori information. Eros is the principal source of perturbations of the spacecraft's trajectory and the principal source of data for determining the orbit. The initial orbit determination strategy is therefore concerned with developing a precise model of Eros. The original plan for Eros orbital operations was to execute a series of rendezvous burns beginning on December 20,1998 and insert into a close Eros orbit in January 1999. As a result of an unplanned termination of the rendezvous burn on December 20, 1998, the NEAR spacecraft continued on its high velocity approach trajectory and passed within 3900 km of Eros on December 23, 1998. The planned rendezvous burn was delayed until January 3, 1999 which resulted in the spacecraft being placed on a trajectory that slowly returns to Eros with a subsequent delay of close Eros orbital operations until February 2001. The flyby of Eros provided a brief glimpse and allowed for a crude estimate of the pole, prime meridian and mass of Eros. More importantly for navigation, orbit determination software was executed in the landmark tracking mode to determine the spacecraft orbit and a preliminary shape and landmark data base has been obtained. The flyby also provided an opportunity to test orbit determination operational procedures that will be used in February of 2001. The initial attitude and spin rate of Eros, as well as estimates of reference landmark locations, are obtained from images of the asteroid. These initial estimates are used as a priori values for a more precise refinement of these parameters by the orbit determination software which combines optical measurements with Doppler tracking data to obtain solutions for the required parameters. As the spacecraft is maneuvered; closer to the asteroid, estimates of spacecraft state, asteroid attitude, solar pressure, landmark locations and Eros physical parameters including mass, moments of inertia and gravity harmonics are determined with increasing precision. The determination of the elements of the inertia tensor of the asteroid is critical to spacecraft orbit determination and prediction of the asteroid attitude. The moments of inertia about the principal axes are also of scientific interest since they provide some insight into the internal mass distribution. Determination of the principal axes moments of inertia will depend on observing free precession in the asteroid's attitude dynamics. Gravity harmonics are in themselves of interest to science. When compared with the asteroid shape, some insight may be obtained into Eros' internal structure. The location of the center of mass derived from the first degree harmonic coefficients give a direct indication of overall mass distribution. The second degree harmonic coefficients relate to the radial distribution of mass. Higher degree harmonics may be compared with surface features to gain additional insight into mass distribution. In this paper, estimates of Eros physical parameters obtained from the December 23,1998 flyby will be presented. This new knowledge will be applied to simplification of Eros orbital operations in February of 2001. The resulting revision to the orbit determination strategy will also be discussed.

  3. An autonomous rendezvous and docking system using cruise missile technologies

    NASA Technical Reports Server (NTRS)

    Jones, Ruel Edwin

    1991-01-01

    In November 1990 the Autonomous Rendezvous & Docking (AR&D) system was first demonstrated for members of NASA's Strategic Avionics Technology Working Group. This simulation utilized prototype hardware from the Cruise Missile and Advanced Centaur Avionics systems. The object was to show that all the accuracy, reliability and operational requirements established for a space craft to dock with Space Station Freedom could be met by the proposed system. The rapid prototyping capabilities of the Advanced Avionics Systems Development Laboratory were used to evaluate the proposed system in a real time, hardware in the loop simulation of the rendezvous and docking reference mission. The simulation permits manual, supervised automatic and fully autonomous operations to be evaluated. It is also being upgraded to be able to test an Autonomous Approach and Landing (AA&L) system. The AA&L and AR&D systems are very similar. Both use inertial guidance and control systems supplemented by GPS. Both use an Image Processing System (IPS), for target recognition and tracking. The IPS includes a general purpose multiprocessor computer and a selected suite of sensors that will provide the required relative position and orientation data. Graphic displays can also be generated by the computer, providing the astronaut / operator with real-time guidance and navigation data with enhanced video or sensor imagery.

  4. An autonomous rendezvous and docking system using cruise missile technologies

    NASA Astrophysics Data System (ADS)

    Jones, Ruel Edwin

    In November 1990 the Autonomous Rendezvous & Docking (AR&D) system was first demonstrated for members of NASA's Strategic Avionics Technology Working Group. This simulation utilized prototype hardware from the Cruise Missile and Advanced Centaur Avionics systems. The object was to show that all the accuracy, reliability and operational requirements established for a space craft to dock with Space Station Freedom could be met by the proposed system. The rapid prototyping capabilities of the Advanced Avionics Systems Development Laboratory were used to evaluate the proposed system in a real time, hardware in the loop simulation of the rendezvous and docking reference mission. The simulation permits manual, supervised automatic and fully autonomous operations to be evaluated. It is also being upgraded to be able to test an Autonomous Approach and Landing (AA&L) system. The AA&L and AR&D systems are very similar. Both use inertial guidance and control systems supplemented by GPS. Both use an Image Processing System (IPS), for target recognition and tracking. The IPS includes a general purpose multiprocessor computer and a selected suite of sensors that will provide the required relative position and orientation data. Graphic displays can also be generated by the computer, providing the astronaut / operator with real-time guidance and navigation data with enhanced video or sensor imagery.

  5. Autonomous control procedures for shuttle rendezvous proximity operations

    NASA Technical Reports Server (NTRS)

    Lea, Robert N.; Mitchell, Eric V.; Goodwin, Mary Ann

    1987-01-01

    The results are presented of a study which uses fuzzy sets to model a Space Shuttle pilot's reasoning and actions while performing rendezvous proximity operation maneuvers. In this model fuzzy sets are used to simulate smooth and continuous actions as would be expected from an experienced pilot and to simulate common sense reasoning in the decision process. The present model assumes visual information available to the Shuttle pilot from the Shuttle Crew Optical Alignment Sighting (COAS) device and the overhead window and rendezvous radar sensor information available to him from an onboard display. This model will be used in a flight analysis simulator to perform studies requiring a large number of runs, each of which currently needs an engineer in the loop to supply the piloting decisions. This work has much broader implications in control of robots such as the Flight Telerobotic Servicer, in automated pilot control and attitude control, and in advisory and evaluation functions that could be used for flight data monitoring or for testing of various rule sets in flight preparation.

  6. Tumbling asteroid rotation with the YORP torque and inelastic energy dissipation

    NASA Astrophysics Data System (ADS)

    Breiter, S.; Murawiecka, M.

    2015-05-01

    The Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect and rotational energy dissipation due to inelastic deformations are two key mechanisms affecting rotation of tumbling asteroids in long term. Each of the effects used to be discussed separately. We present the first results concerning a simulation of their joint action. Asteroids (3103) Eger and (99942) Apophis, as well as their scaled variants, are used as test bodies. Plugging in the dissipation destroys limit cycles of the pure YORP, but creates a new asymptotic state of stationary tumbling with a fixed rotation period. The present model does not contradict finding Eger in the principal axis rotation. For Apophis, the model suggests that its current rotation state should be relatively young. In general, the fraction of initial conditions leading to the principal axis rotation is too small, compared to the actual data. The model requires a stronger energy dissipation and weaker YORP components in the nutation angle and obliquity.

  7. Run-and-tumble particles, telegrapher’s equation and absorption problems with partially reflecting boundaries

    NASA Astrophysics Data System (ADS)

    Angelani, Luca

    2015-12-01

    Absorption problems of run-and-tumble particles, described by the telegrapher's equation, are analyzed in one space dimension considering partially reflecting boundaries. Exact expressions for the probability distribution function in the Laplace domain and for the mean time to absorption are given, discussing some interesting limits (Brownian and wave limit, large volume limit) and different case studies (semi-infinite segment, equal and symmetric boundaries, totally/partially reflecting boundaries).

  8. Tumbling Motion of Elliptical Particles in Viscous Two-Dimensional Flow

    E-print Network

    Gerald H. Ristow

    2000-04-18

    The settling dynamics of spherical and elliptical particles in a viscous Newtonian fluid are investigated numerically using a finite difference technique. The terminal velocity for spherical particles is calculated for different system sizes and the extrapolated value for an infinite system size is compared to the Oseen approximation. Special attention is given to the settling and tumbling motion of elliptical particles where their terminal velocity is compared with the one of the surface equivalent spherical particle.

  9. The Evolution of the Rendezvous Profile During the Space Shuttle Program

    NASA Technical Reports Server (NTRS)

    Summa, William R.

    2010-01-01

    The rendezvous and proximity operations approach design techniques for space shuttle missions has changed significantly during the life of the program in response to new requirements that were not part of the original mission design. The flexibility of the shuttle onboard systems design and the mission planning process has allowed the program to meet these requirements. The design of the space shuttle and the shift from docking to grappling with a robotic ann prevented use of legacy Apollo rendezvous techniques. Over the life of the shuttle program the rendezvous profile has evolved due to several factors, including lowering propellant consumption and increasing flexibility in mission planning. Many of the spacecraft that the shuttle rendezvoused with had unique requirements that drove the creation of mission-unique proximity operations. The dockings to the Russian Mir space station and International Space Station (ISS) required further evolution of rendezvous and proximity operations techniques and additional sensors to enhance crew situational awareness. After the Columbia accident, a Rendezvous Pitch Maneuver (RPM) was added to allow tile photography from ISS. Lessons learned from these rendezvous design changes are applicable to future vehicle designs and operations concepts.

  10. Simulation of the flow field and tumbling dynamics of multiply flagellated bacterium

    NASA Astrophysics Data System (ADS)

    Larson, Ronald; Watari, Nobuhiko

    2009-11-01

    To study the hydrodynamics of swimming of multi-flagellated bacteria, such as Escherichia coli, we develop a simulation method using a bead-spring model to account for the hydrodynamic and the mechanical interactions between multiple flagella and the cell body, the reversal of the rotation of a flagellum in a tumble and associated polymorphic transformations of the flagellum. This simulation reproduces the experimentally observed behaviors of E. coli, namely, a three-dimensional random-walk trajectory in run-and-tumble motion and steady clockwise swimming near a wall. Here we show using a modeled cell that the polymorphic transformation of flagellum in a tumble facilitates the reorientation of the cell, and that the time-averaged flow field near a cell in a run has double-layered helical streamlines. Moreover, the instantaneous flow field, which is strongly time-dependent, is more than 10-fold larger in magnitude than the time-averaged flow, large enough to affect the migration behavior of surrounding chemoattractants, with the Peclet number for these molecules being larger than one near a swimming cell.

  11. Rendezvous Integration Complexities of NASA Human Flight Vehicles

    NASA Technical Reports Server (NTRS)

    Brazzel, Jack P.; Goodman, John L.

    2009-01-01

    Propellant-optimal trajectories, relative sensors and navigation, and docking/capture mechanisms are rendezvous disciplines that receive much attention in the technical literature. However, other areas must be considered. These include absolute navigation, maneuver targeting, attitude control, power generation, software development and verification, redundancy management, thermal control, avionics integration, robotics, communications, lighting, human factors, crew timeline, procedure development, orbital debris risk mitigation, structures, plume impingement, logistics, and in some cases extravehicular activity. While current and future spaceflight programs will introduce new technologies and operations concepts, the complexity of integrating multiple systems on multiple spacecraft will remain. The systems integration task may become more difficult as increasingly complex software is used to meet current and future automation, autonomy, and robotic operation requirements.

  12. NASA Automated Rendezvous and Capture Review. Executive summary

    NASA Technical Reports Server (NTRS)

    1991-01-01

    In support of the Cargo Transfer Vehicle (CTV) Definition Studies in FY-92, the Advanced Program Development division of the Office of Space Flight at NASA Headquarters conducted an evaluation and review of the United States capabilities and state-of-the-art in Automated Rendezvous and Capture (AR&C). This review was held in Williamsburg, Virginia on 19-21 Nov. 1991 and included over 120 attendees from U.S. government organizations, industries, and universities. One hundred abstracts were submitted to the organizing committee for consideration. Forty-two were selected for presentation. The review was structured to include five technical sessions. Forty-two papers addressed topics in the five categories below: (1) hardware systems and components; (2) software systems; (3) integrated systems; (4) operations; and (5) supporting infrastructure.

  13. Some impulsive rendezvous trajectories and their possible optimality.

    NASA Technical Reports Server (NTRS)

    Peltier, J. P.

    1972-01-01

    Two- and three-impulse trajectories are investigated for fixed-time, fixed-angle rendezvous between vacant circular coplanar orbits, for trip angles less than, or equal to 2 pi in magnitude. For two-impulse trajectories, general features of the characteristic velocity function are outlined. Parameters of the intermediate orbit are reviewed. Attention is given to limiting cases. Computation of the adjoint system helps to define the domain of possible optimality foajectories: it is a closed domain in the trip time, trip angle plane. Waiting periods on terminal orbits are considered. The domain of possible optimality is defined using Lawden's primer vrtory. This domain extends to infinity if the radius ratio of terminal orbits is less than 15.6. Three-impulse trajectories are tried in cases where two-impulse trajectories, with or without cost, have been found nonoptimal. Improvements on the characteristic velocity are thus obtained.

  14. Orion Rendezvous, Proximity Operations, and Docking Design and Analysis

    NASA Technical Reports Server (NTRS)

    D'Souza, Christopher; Hanak, F. Chad; Spehar, Pete; Clark, Fred D.; Jackson, Mark

    2007-01-01

    The Orion vehicle will be required to perform rendezvous, proximity operations, and docking with the International Space Station (ISS) and the Earth Departure Stage (EDS)/Lunar Landing Vehicle (LLV) stack in Low Earth Orbit (LEO) as well as with the Lunar Landing Vehicle in Low Lunar Orbit (LLO). The RPOD system, which consists of sensors, actuators, and software is being designed to be flexible and robust enough to perform RPOD with different vehicles in different environments. This paper will describe the design and the analysis which has been performed to date to allow the vehicle to perform its mission. Since the RPOD design touches on many areas such as sensors selection and placement, trajectory design, navigation performance, and effector performance, it is inherently a systems design problem. This paper will address each of these issues in order to demonstrate how the Orion RPOD has been designed to accommodate and meet all the requirements levied on the system.

  15. Rendezvous, proximity operations and capture quality function deployment report

    NASA Technical Reports Server (NTRS)

    Lamkin, Stephen L. (editor)

    1991-01-01

    Rendezvous, Proximity Operations, and Capture (RPOC) is a missions operations area which is extremely important to present and future space initiatives and must be well planned and coordinated. To support this, a study team was formed to identify a specific plan of action using the Quality Function Deployment (QFD) process. This team was composed of members from a wide spectrum of engineering and operations organizations which are involved in the RPOC technology area. The key to this study's success is an understanding of the needs of potential programmatic customers and the technology base available for system implementation. To this end, the study team conducted interviews with a variety of near term and future programmatic customers and technology development sponsors. The QFD activity led to a thorough understanding of the needs of these customers in the RPOC area, as well as the relative importance of these needs.

  16. Rendezvous, proximity operations and capture quality function deployment report

    NASA Astrophysics Data System (ADS)

    Lamkin, Stephen L.

    1991-12-01

    Rendezvous, Proximity Operations, and Capture (RPOC) is a missions operations area which is extremely important to present and future space initiatives and must be well planned and coordinated. To support this, a study team was formed to identify a specific plan of action using the Quality Function Deployment (QFD) process. This team was composed of members from a wide spectrum of engineering and operations organizations which are involved in the RPOC technology area. The key to this study's success is an understanding of the needs of potential programmatic customers and the technology base available for system implementation. To this end, the study team conducted interviews with a variety of near term and future programmatic customers and technology development sponsors. The QFD activity led to a thorough understanding of the needs of these customers in the RPOC area, as well as the relative importance of these needs.

  17. A Comparison Between Orion Automated and Space Shuttle Rendezvous Techniques

    NASA Technical Reports Server (NTRS)

    Ruiz, Jose O,; Hart, Jeremy

    2010-01-01

    The Orion spacecraft will replace the space shuttle and will be the first human spacecraft since the Apollo program to leave low earth orbit. This vehicle will serve as the cornerstone of a complete space transportation system with a myriad of mission requirements necessitating rendezvous to multiple vehicles in earth orbit, around the moon and eventually beyond . These goals will require a complex and robust vehicle that is, significantly different from both the space shuttle and the command module of the Apollo program. Historically, orbit operations have been accomplished with heavy reliance on ground support and manual crew reconfiguration and monitoring. One major difference with Orion is that automation will be incorporated as a key element of the man-vehicle system. The automated system will consist of software devoted to transitioning between events based on a master timeline. This effectively adds a layer of high level sequencing that moves control of the vehicle from one phase to the next. This type of automated control is not entirely new to spacecraft since the shuttle uses a version of this during ascent and entry operations. During shuttle orbit operations however many of the software modes and hardware switches must be manually configured through the use of printed procedures and instructions voiced from the ground. The goal of the automation scheme on Orion is to extend high level automation to all flight phases. The move towards automation represents a large shift from current space shuttle operations, and so these new systems will be adopted gradually via various safeguards. These include features such as authority-to-proceed, manual down modes, and functional inhibits. This paper describes the contrast between the manual and ground approach of the space shuttle and the proposed automation of the Orion vehicle. I will introduce typical orbit operations that are common to all rendezvous missions and go on to describe the current Orion automation architecture and contrast it with shuttle rendezvous techniques and circumstances. The shuttle rendezvous profile is timed to take approximately 3 days from orbit insertion to docking at the International Space Station (ISS). This process can be divided into 3 phases: far-field, mid-field and proximity operations. The far-field stage is characterized as the most quiescent phase. The spacecraft is usually too far to navigate using relative sensors and uses the Inertial Measurement Units (IMU s) to numerically solve for its position. The maneuvers are infrequent, roughly twice per day, and are larger than other burns in the profile. The shuttle uses this opportunity to take extensive ground based radar updates and keep high fidelity orbit states on the ground. This state is then periodically uplinked to the shuttle computers. The targeting solutions for burn maneuvers are also computed on the ground and uplinked. During the burn the crew is responsible for setting the shuttle attitude and configuring the propulsion system for ignition. Again this entire process is manually driven by both crew and ground activity. The only automatic processes that occur are associated with the real-time execution of the burn. The Orion automated functionality will seek to relieve the workload of both the crew and ground during this phase

  18. Study of a comet rendezvous mission, volume 1

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The feasibility, scientific objectives, modes of exploration and implementation alternatives of a rendezvous mission to Encke's comet in 1984 are considered. Principal emphasis is placed on developing the scientific rationale for such a mission, based on available knowledge and best estimates of this comet's physical characteristics, including current theories of its origin, evolution and composition. Studied are mission profile alternatives, performance tradeoffs, preferred exploration strategy, and a spacecraft design concept capable of performing this mission. The study showed that the major scientific objectives can be met by a Titan IIID/Centaur-launched 17.5 kw solar electric propulsion spacecraft which carries 60 kg of scientific instruments and is capable of extensive maneuvering within the comet envelope to explore the coma, tail and nucleus.

  19. Longitudinal Trim and Tumble Characteristics of a 0.057-Scale Model of the Chance Vought XF7U-1 Airplane, TED NO. NACA DE311

    NASA Technical Reports Server (NTRS)

    Bryant, Robert L.

    1948-01-01

    Based on results of longitudinal trim and tumble tests of a 0.057-scale model of the Chance Vought XF7U-1 airplane, the following conclusions regarding the trim and tumble characteristics of the airplane have been drawn: 1. The airplane will not trim at any unusual or uncontrolled angles of attack. 2. The airplane will not tumble with the center of gravity located forward of 24 percent of the mean aerodynamic chord. When the center of gravity is located at 24 percent of the mean aerodynamic chord and slats are extended and elevators are deflected full up, the airplane may tumble if given an external positive pitching moment. 3. The tumbling motion obtained will be readily terminated by deflecting the elevators full down so as to oppose the rotation. 4. The accelerations encountered during an established tumble may be dangerous to the pilot and, therefore, action should be taken to terminate a tumble immediately upon its inception. 5. Simultaneous opening of two wing-tip parachutes having diameters of 4 feet or larger and having drag coefficients of approximately 0.7 will effectively terminate the tumble. 6. Model results indicate that the pilot will not be struck by the airplane if it becomes necessary to leave the airplane during a tumble. The pilot may require aid from an ejection-seat arrangement.

  20. Avionics and control system development for mid-air rendezvous of two unmanned aerial vehicles

    E-print Network

    Park, Sanghyuk, 1973-

    2004-01-01

    A flight control system was developed to achieve mid-air rendezvous of two unmanned aerial vehicles (UAVs) as a part of the Parent Child Unmanned Aerial Vehicle (PCUAV) project at MIT and the Draper Laboratory. A lateral ...

  1. A vision based control system for autonomous rendezvous and capture of a Mars Orbital Sample

    E-print Network

    Jyothindran, Vishnu

    2013-01-01

    NASA's Mars Sample Return (MSR) mission involves many challenging operations. The current mission scenario utilizes a small Orbiting Sample (OS) satellite, launched from the surface of Mars, which will rendezvous with an ...

  2. An application of linear covariance analysis to the design of responsive near-rendezvous missions

    E-print Network

    Visser, Benjamin Lee

    2007-01-01

    This thesis investigates a new class of launch vehicles capable of being released from an aircraft which ultimately have the goal of achieving near-rendezvous conditions at orbital altitudes up to 800 km. These launch ...

  3. Rough-and-Tumble Play and the Regulation of Aggression: An Observational Study of Father–Child Play Dyads

    PubMed Central

    Flanders, Joseph L.; Leo, Vanessa; Paquette, Daniel; Pihl, Robert O.; Séguin, Jean R.

    2012-01-01

    Rough-and-tumble play (RTP) is a common form of play between fathers and children. It has been suggested that RTP can contribute to the development of selfregulation. This study addressed the hypothesis that the frequency of father–child RTP is related to the frequency of physically aggressive behavior in early childhood. This relationship was expected to be moderated by the dominance relationship between father and son during play. Eighty-five children between the ages of 2 and 6 years were videotaped during a free-play session with their fathers in their homes and questionnaire data was collected about father–child RTP frequency during the past year. The play dyads were rated for the degree to which the father dominated play interactions. A significant statistical interaction revealed that RTP frequency was associated with higher levels of physical aggression in children whose fathers were less dominant. These results indicate that RTP is indeed related to physical aggression, though this relationship is moderated by the degree to which the father is a dominant playmate. PMID:19431190

  4. Intra-urinoma Rendezvous Using a Transconduit Approach to Re-establish Ureteric Integrity

    SciTech Connect

    Anderson, Hugh Alyas, Faisal; Edwin, Patrick Joseph

    2005-01-15

    Ureteric discontinuity following injury has been traditionally treated surgically. With the advent of improved interventional instrumentation it is possible to stent these lesions percutaneously, retrogradely or failing that using a combined (rendezvous) technique. We describe an intra-urinoma rendezvous procedure combining a percutaneous antegrade-transconduit retrograde technique of stent insertion to successfully re-establish ureteric integrity that was used following the failure of a percutaneous retrograde approach. We illustrate its usefulness as an alternative to surgery.

  5. Solar electric propulsion for terminal flight to rendezvous with comets and asteroids. [using guidance algorithm

    NASA Technical Reports Server (NTRS)

    Bennett, A.

    1973-01-01

    A guidance algorithm that provides precise rendezvous in the deterministic case while requiring only relative state information is developed. A navigation scheme employing only onboard relative measurements is built around a Kalman filter set in measurement coordinates. The overall guidance and navigation procedure is evaluated in the face of measurement errors by a detailed numerical simulation. Results indicate that onboard guidance and navigation for the terminal phase of rendezvous is possible with reasonable limits on measurement errors.

  6. NEP for a Kuiper Belt Object Rendezvous Mission

    SciTech Connect

    HOUTS,MICHAEL G.; LENARD,ROGER X.; LIPINSKI,RONALD J.; PATTON,BRUCE; POSTON,DAVID I.; WRIGHT,STEVEN A.

    1999-11-03

    Kuiper Belt Objects (KBOs) are a recently-discovered set of solar system bodies which lie at about the orbit of Pluto (40 AU) out to about 100 astronomical units (AU). There are estimated to be about 100,000 KBOS with a diameter greater than 100 km. KBOS are postulated to be composed of the pristine material which formed our solar system and may even have organic materials in them. A detailed study of KBO size, orbit distribution, structure, and surface composition could shed light on the origins of the solar system and perhaps even on the origin of life in our solar system. A rendezvous mission including a lander would be needed to perform chemical analysis of the surface and sub-surface composition of KBOS. These requirements set the size of the science probe at around a ton. Mission analyses show that a fission-powered system with an electric thruster could rendezvous at 40 AU in about 13.0 years with a total {Delta}V of 46 krnk. It would deliver a 1000-kg science payload while providing ample onboard power for relaying data back to earth. The launch mass of the entire system (power, thrusters, propellant, navigation, communication, structure, science payload, etc.) would be 7984 kg if it were placed into an earth-escape trajectory (C=O). Alternatively, the system could be placed into a 700-km earth orbit with more propellant,yielding a total mass in LEO of 8618 kg, and then spiral out of earth orbit to arrive at the KBO in 14.3 years. To achieve this performance, a fission power system with 100 kW of electrical power and a total mass (reactor, shield, conversion, and radiator) of about 2350 kg. Three possible configurations are proposed: (1) a UZrH-fueled, NaK-cooled reactor with a steam Rankine conversion system, (2) a UN-fueled gas-cooled reactor with a recuperated Brayton conversion system, and (3) a UN-fueled heatpipe-cooled reactor with a recuperated Brayton conversion system. (Boiling and condensation in the Rankine system is a technical risk at present.) All three of these systems have the potential to meet the weight requirement for the trip and to be built in the near term.

  7. Design and Implementation of the Automated Rendezvous Targeting Algorithms for Orion

    NASA Technical Reports Server (NTRS)

    DSouza, Christopher; Weeks, Michael

    2010-01-01

    The Orion vehicle will be designed to perform several rendezvous missions: rendezvous with the ISS in Low Earth Orbit (LEO), rendezvous with the EDS/Altair in LEO, a contingency rendezvous with the ascent stage of the Altair in Low Lunar Orbit (LLO) and a contingency rendezvous in LLO with the ascent and descent stage in the case of an aborted lunar landing. Therefore, it is not difficult to realize that each of these scenarios imposes different operational, timing, and performance constraints on the GNC system. To this end, a suite of on-board guidance and targeting algorithms have been designed to meet the requirement to perform the rendezvous independent of communications with the ground. This capability is particularly relevant for the lunar missions, some of which may occur on the far side of the moon. This paper will describe these algorithms which are designed to be structured and arranged in such a way so as to be flexible and able to safely perform a wide variety of rendezvous trajectories. The goal of the algorithms is not to merely fly one specific type of canned rendezvous profile. Conversely, it was designed from the start to be general enough such that any type of trajectory profile can be flown.(i.e. a coelliptic profile, a stable orbit rendezvous profile, and a expedited LLO rendezvous profile, etc) all using the same rendezvous suite of algorithms. Each of these profiles makes use of maneuver types which have been designed with dual goals of robustness and performance. They are designed to converge quickly under dispersed conditions and they are designed to perform many of the functions performed on the ground today. The targeting algorithms consist of a phasing maneuver (NC), an altitude adjust maneuver (NH), and plane change maneuver (NPC), a coelliptic maneuver (NSR), a Lambert targeted maneuver, and several multiple-burn targeted maneuvers which combine one of more of these algorithms. The derivation and implementation of each of these algorithms will be discussed in detail, as well and the Rendezvous Targeting "wrapper" which will sequentially tie them all together into a single onboard targeting tool which can produce a final integrated rendezvous trajectory. In a similar fashion, the various guidance modes available for flying out each of these maneuvers will be discussed as well. This paradigm of having the onboard guidance & targeting capability described above is different than the way the Space Shuttle has operated thus far. As a result, a discussion of these differences in terms of operations and ground and crew intervention will also be discussed. However, the general framework of how the mission designers on the ground first perform all mission design and planning functions, and then uplink that burn plan to the vehicle ensures that the ground will be involved to ensure safety and reliability. The only real difference is which of these functions will be done onboard vs. on the ground as done currently. Finally, this paper will describe the performance of each of these algorithms individually as well as the entire suite of algorithms as applied to the Orion ISS and EDS/Altair rendezvous missions in LEO. These algorithms have been incorporated in both a Linear Covariance environment and a Monte Carlo environment and the results of these dispersion analyses will be presented in the paper as well.

  8. Space shuttle Ku-band integrated rendezvous radar/communications system study

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The results are presented of work performed on the Space Shuttle Ku-Band Integrated Rendezvous Radar/Communications System Study. The recommendations and conclusions are included as well as the details explaining the results. The requirements upon which the study was based are presented along with the predicted performance of the recommended system configuration. In addition, shuttle orbiter vehicle constraints (e.g., size, weight, power, stowage space) are discussed. The tradeoffs considered and the operation of the recommended configuration are described for an optimized, integrated Ku-band radar/communications system. Basic system tradeoffs, communication design, radar design, antenna tradeoffs, antenna gimbal and drive design, antenna servo design, and deployed assembly packaging design are discussed. The communications and radar performance analyses necessary to support the system design effort are presented. Detailed derivations of the communications thermal noise error, the radar range, range rate, and angle tracking errors, and the communications transmitter distortion parameter effect on crosstalk between the unbalanced quadriphase signals are included.

  9. Handling Neighbor Discovery and Rendezvous Consistency with Weighted Quorum-Based Approach.

    PubMed

    Own, Chung-Ming; Meng, Zhaopeng; Liu, Kehan

    2015-01-01

    Neighbor discovery and the power of sensors play an important role in the formation of Wireless Sensor Networks (WSNs) and mobile networks. Many asynchronous protocols based on wake-up time scheduling have been proposed to enable neighbor discovery among neighboring nodes for the energy saving, especially in the difficulty of clock synchronization. However, existing researches are divided two parts with the neighbor-discovery methods, one is the quorum-based protocols and the other is co-primality based protocols. Their distinction is on the arrangements of time slots, the former uses the quorums in the matrix, the latter adopts the numerical analysis. In our study, we propose the weighted heuristic quorum system (WQS), which is based on the quorum algorithm to eliminate redundant paths of active slots. We demonstrate the specification of our system: fewer active slots are required, the referring rate is balanced, and remaining power is considered particularly when a device maintains rendezvous with discovered neighbors. The evaluation results showed that our proposed method can effectively reschedule the active slots and save the computing time of the network system. PMID:26404297

  10. Handling Neighbor Discovery and Rendezvous Consistency with Weighted Quorum-Based Approach

    PubMed Central

    Own, Chung-Ming; Meng, Zhaopeng; Liu, Kehan

    2015-01-01

    Neighbor discovery and the power of sensors play an important role in the formation of Wireless Sensor Networks (WSNs) and mobile networks. Many asynchronous protocols based on wake-up time scheduling have been proposed to enable neighbor discovery among neighboring nodes for the energy saving, especially in the difficulty of clock synchronization. However, existing researches are divided two parts with the neighbor-discovery methods, one is the quorum-based protocols and the other is co-primality based protocols. Their distinction is on the arrangements of time slots, the former uses the quorums in the matrix, the latter adopts the numerical analysis. In our study, we propose the weighted heuristic quorum system (WQS), which is based on the quorum algorithm to eliminate redundant paths of active slots. We demonstrate the specification of our system: fewer active slots are required, the referring rate is balanced, and remaining power is considered particularly when a device maintains rendezvous with discovered neighbors. The evaluation results showed that our proposed method can effectively reschedule the active slots and save the computing time of the network system. PMID:26404297

  11. Hubble Servicing Challenges Drive Innovation of Shuttle Rendezvous Techniques

    NASA Technical Reports Server (NTRS)

    Goodman, John L.; Walker, Stephen R.

    2009-01-01

    Hubble Space Telescope (HST) servicing, performed by Space Shuttle crews, has contributed to what is arguably one of the most successful astronomy missions ever flown. Both nominal and contingency proximity operations techniques were developed to enable successful servicing, while lowering the risk of damage to HST systems, and improve crew safety. Influencing the development of these techniques were the challenges presented by plume impingement and HST performance anomalies. The design of both the HST and the Space Shuttle was completed before the potential of HST contamination and structural damage by shuttle RCS jet plume impingement was fully understood. Relative navigation during proximity operations has been challenging, as HST was not equipped with relative navigation aids. Since HST reached orbit in 1990, proximity operations design for servicing missions has evolved as insight into plume contamination and dynamic pressure has improved and new relative navigation tools have become available. Servicing missions have provided NASA with opportunities to gain insight into servicing mission design and development of nominal and contingency procedures. The HST servicing experiences and lessons learned are applicable to other programs that perform on-orbit servicing and rendezvous, both human and robotic.

  12. Run and tumble, run and reverse, or run reverse and flick - who wins the chemotaxis race?

    NASA Astrophysics Data System (ADS)

    Zaburdaev, Vasily; Denisov, Sergey; Weitz, David

    2012-02-01

    Run and tumble of E.coli bacteria is a well understood example of the stochastic cell motion that is alternated in the presence of signaling chemicals. By regulating the tumbling frequency bacteria are able to navigate toward the food sources. Another bacteria that use twitching to move on a surface, M. xanthus, utilize a different strategy - at the end of the run they completely reverse the direction of motion and continue moving in the opposite direction. The frequency of reversals was shown to be connected to the chemotactic response of the cell. Recently yet another pattern was discovered in marine bacteria V. alginolyticus which alternate sharp reversals with flicks -- making a turn to an angle with a broad distribution and centered around 90 degrees. In this work we are presenting a theoretical framework that describes all above motion patterns. As a highlight of the developed approach we find the exact analytical expressions for the mean squared displacement of moving cells for arbitrary distribution of run times. That allows us to quantitatively compare the performance of bacteria exploring the environment with and without signaling chemicals and, therefore, to find the winner of the chemotactic race.

  13. Warps and Bars from the External Tidal Torques of Tumbling Dark Halos

    NASA Astrophysics Data System (ADS)

    Dubinski, John; Chakrabarty, Dalia

    2009-10-01

    The dark matter halos in ? cold dark matter cosmological simulations are triaxial and highly flattened. In many cases, these triaxial equilibria are also tumbling slowly, typically about their short axes, with periods of order a Hubble time. Halos may therefore exert a slowly changing external torque on spiral galaxies that can affect their dynamical evolution in interesting ways. We examine the effect of the external torques exerted by a tumbling quadrupolar tidal field on the evolution of spiral galaxies using N-body simulations with realistic, disk galaxy models. We measure the amplitude of the external quadrupole moments of dark halos in cosmological simulations and use these to force disk galaxy models in a series of N-body experiments for a range of pattern speeds. We find that the torques are strong enough to induce long-lived transient warps in disks similar to those observed in real spirals and also induce the bar instability at later times in some galaxy models that are otherwise stable for long periods of time in isolation. We also observe forced spiral structure near the edge of the disk where normally self gravity is too weak to be responsible for such a structure. This overlooked influence of dark halos may well be responsible for many of the peculiar aspects of disk galaxy dynamics.

  14. A stochastic model for bacterial dynamics toward point food sources with emergent run-and-tumble

    NASA Astrophysics Data System (ADS)

    Jashnsaz, Hossein; Nguyen, Tyler; Petrache, Horia; Presse, Steve; StatPhysBio Team

    2015-03-01

    Despite stark differences in chemotactic signaling networks and flagellar physiology across bacterial species, all bacteria sense their environment through a series of stochastic detection events (``hits'') at their chemoreceptors and bias their random walk on the basis of this information. We present a general statistical model describing how bacteria locate point sources of food on the basis of stochastic event detection, rather than gradient information. We show how model parameters can be directly inferred using maximum likelihood methods from microscopy tracking data. We find that ``run-and-tumble'' dynamics naturally emerge from our statistical model and recapitulate known results from experiments when we consider bacterial dynamics in well-controlled chemoattractant gradients. However, our model goes beyond reproducing known run-and-tumble statistics. It also makes a number of predictions unique to bacteria tracking point sources. In our model, all parameters are directly inferred from tracking data thus there are no adjustable parameters; detection events by bacteria are assumed stochastic as they occur in nature; and our ``top-down'' modeling approach is broadly applicable across bacterial species. SP acknowledges the NSF (MCB-1412259), the Purdue Research Foundation and his IUPUI Start-up.

  15. Integrated GPS/INS navigation system design for autonomous spacecraft rendezvous

    NASA Astrophysics Data System (ADS)

    Gaylor, David Edward

    2003-10-01

    The goal of the NASA Space Launch Initiative (SLI) program is to advance the technologies for the next generation reusable launch vehicle (RLV). The SLI program has identified automated rendezvous and docking as an area requiring further research and development. Currently, the Space Shuttle uses a partially manual system for rendezvous, but a fully automated system could be safer and more reliable. Previous studies have shown that it is feasible to use the Global Positioning System (GPS) for spacecraft navigation during rendezvous with the International Space Station (ISS). However, these studies have not accounted for the effects of GPS signal blockage and multipath in the vicinity of the ISS, which make a GPS-only navigation system less accurate and reliable. One possible solution is to combine GPS with an inertial navigation system (INS). The integration of GPS and INS can be achieved using a Kalman filter. GPS/INS systems have been used in aircraft for many years and have also been used in launch vehicles. However, the performance of GPS/INS systems in orbit and during spacecraft rendezvous has not been characterized. The primary objective of this research is to evaluate the ability of an integrated GPS/INS to provide accurate navigation solutions during a rendezvous scenario where the effects of ISS signal blockage, multipath and delta-v maneuvers degrade GPS-only navigation. In order to accomplish this, GPS-only and GPS/INS Kalman filters have been developed for both absolute and relative navigation, as well as a new statistical multipath model for spacecraft operating near the ISS. Several factors that affect relative navigation performance were studied, including: filter tuning, GPS constellation geometry, rendezvous approach direction, and inertial sensor performance. The results showed that each of these factors has a large impact on relative navigation performance. Finally, it has been demonstrated that a GPS/INS system based on medium accuracy aircraft avionics-grade inertial sensors does not provide adequate relative navigation performance for rendezvous with the ISS unless accelerometer thresholding is used. However, the use of state-of-the-art inertial navigation sensors provides relative position accuracy which is adequate for rendezvous with ISS if an additional rendezvous sensor is included.

  16. Flight data results of estimate fusion for spacecraft rendezvous navigation from shuttle mission STS-69

    NASA Technical Reports Server (NTRS)

    Carpenter, J. Russell; Bishop, Robert H.

    1996-01-01

    A recently developed rendezvous navigation fusion filter that optimally exploits existing distributed filters for rendezvous and GPS navigation to achieve the relative and inertial state accuracies of both in a global solution is utilized here to process actual flight data. Space Shuttle Mission STS-69 was the first mission to date which gathered data from both the rendezvous and Global Positioning System filters allowing, for the first time, a test of the fusion algorithm with real flight data. Furthermore, a precise best estimate of trajectory is available for portions of STS-69, making possible a check on the performance of the fusion filter. In order to successfully carry out this experiment with flight data, two extensions to the existing scheme were necessary: a fusion edit test based on differences between the filter state vectors, and an underweighting scheme to accommodate the suboptimal perfect target assumption made by the Shuttle rendezvous filter. With these innovations, the flight data was successfully fused from playbacks of downlinked and/or recorded measurement data through ground analysis versions of the Shuttle rendezvous filter and a GPS filter developed for another experiment. The fusion results agree with the best estimate of trajectory at approximately the levels of uncertainty expected from the fusion filter's covariance matrix.

  17. Monsters, Magic and Mr Psycho: A Biocultural Approach to Rough and Tumble Play in the Early Years of Primary School

    ERIC Educational Resources Information Center

    Jarvis, Pam

    2007-01-01

    This paper focuses upon the developmental role of rough and tumble (R&T) play with particular attention to the narratives that children use to underpin such activities. A review of the literature suggests that current early years research and practice pays scant attention to children's outdoor free play activities. A piece of original research is…

  18. Physical Activity Play and Preschool Children's Peer Acceptance: Distinctions between Rough-and-Tumble and Exercise Play

    ERIC Educational Resources Information Center

    Lindsey, Eric W.

    2014-01-01

    Research Findings: Two forms of exercise play (toy mediated and non-mediated) and 2 forms of rough-and-tumble (R&T) play (chase and fighting) were examined in relation to preschoolers' peer competence. A total of 148 preschoolers (78 boys, 89 Euro-Americans) were observed during free play at their university-sponsored child care center.…

  19. Manned maneuvering unit applications for automated rendezvous and capture

    NASA Technical Reports Server (NTRS)

    Brehm, Donald L.; Cuseo, John A.; Lenda, Joseph A.; Ray, Lex; Whitsett, C. Edward

    1991-01-01

    Automated Rendezvous and Capture (AR&C) is an important technology to multiple National Aeronautics and Space Administration (NASA) programs and centers. The recent Johnson Spacecraft Center (JSC) AR&C Quality Function Deployment (QFD) has listed on-orbit demonstration of related technologies as a near term priority. Martin Marietta has been evaluating use of the Manned Maneuvering Unit (MMU) for a low cost near term on-orbit demonstration of AR&C technologies such as control algorithms, sensors, and processors as well as system level performance. The MMU Program began in 1979 as the method of repairing the Space Shuttle (STS) Thermal Protection System (the tiles). The units were not needed for this task, but were successfully employed during three Shuttle flights in 1984: a test flight was flown in in February as proof of concept, in April the MMU participated in the Solar Max Repair Mission, and in November the MMU's returned to space to successfully rescue the two errant satellites, Westar and Palapa. In the intervening years, the MMU simulator and MMU Qualification Test Unit (QTU) have been used for Astronaut training and experimental evaluations. The Extra-Vehicular Activities (EVA) Retriever has used the QTU, in an unmanned form, as a free-flyer on the Johnson Space Center (JSC) Precision Air Bearing Floor (PABF). Currently, the MMU is undergoing recertification for flight. The two flight units were removed from storage in September, 1991 and evaluation tests were performed. The tests demonstrated that the units are in good shape with no discrepancies that would preclude further use. The Return to Flight effort is currently clearing up recertification issues and evaluating the design against the present Shuttle environments.

  20. Performance capabilities of a Phase One Automatic Rendezvous and Capture System

    NASA Technical Reports Server (NTRS)

    Kachmar, Peter M.; Polutchko, Robert J.; Matusky, Martin

    1991-01-01

    This paper presents an analysis of the performance of the existing 'Phase One' AR&C system developed at the C.S. Draper Laboratory for both the rendezvous and proximity operations mission phases. This material has been developed as a result of Draper Laboratory involvement through NASA's Johnson Space Center in the development of the flight proven IGN&C rendezvous systems for Apollo, Skylab, and Shuttle. The development of these systems using Draper computer simulations has required automation of all crew inputs to the IGN&C system and thus provided the unique opportunity to develop and test those system capabilities required for AR&C. This paper expands upon the material in the papers presented by the authors at the NASA Autonomous Rendezvous and Docking Conference held at JSC on August 15-16, 1991.

  1. Robust rendezvous maneuver point conditions. M.S. Thesis - Massachusetts Inst. of Tech.

    NASA Technical Reports Server (NTRS)

    Fogle, Debra Ann

    1992-01-01

    This study develops rendezvous maneuver point conditions that are robust to one dimensional errors in state estimation and burn execution. Allowing small deviations in the time of intercept provides a degree of freedom that can be used to compensate for these errors. The direction of allowable burn deviation is developed for errors in state estimation and burn execution. The maneuver points for which the error is aligned with the insensitive direction provide excellent rendezvous initiation points. The method is applied to sample rendezvous for vehicles in circular and elliptic orbits. Robust maneuver points are selected and the vehicles' relative motion plotted, demonstrating the validity of the maneuver points. Finally, a graphical illustration of the error focusing effect is demonstrated by means of a Monte Carlo simulation.

  2. An Assessment of the Technology of Automated Rendezvous and Capture in Space

    NASA Technical Reports Server (NTRS)

    Polites, M. E.

    1998-01-01

    This paper presents the results of a study to assess the technology of automated rendezvous and capture (AR&C) in space. The outline of the paper is as follows. First, the history of manual and automated rendezvous and capture and rendezvous and dock is presented. Next, the need for AR&C in space is established. Then, today's technology and ongoing technology efforts related to AR&C in space are reviewed. In light of these, AR&C systems are proposed that meet NASA's future needs, but can be developed in a reasonable amount of time with a reasonable amount of money. Technology plans for developing these systems are presented; cost and schedule are included.

  3. Methodology for Developing a Probabilistic Risk Assessment Model of Spacecraft Rendezvous and Dockings

    NASA Technical Reports Server (NTRS)

    Farnham, Steven J., II; Garza, Joel, Jr.; Castillo, Theresa M.; Lutomski, Michael

    2011-01-01

    In 2007 NASA was preparing to send two new visiting vehicles carrying logistics and propellant to the International Space Station (ISS). These new vehicles were the European Space Agency s (ESA) Automated Transfer Vehicle (ATV), the Jules Verne, and the Japanese Aerospace and Explorations Agency s (JAXA) H-II Transfer Vehicle (HTV). The ISS Program wanted to quantify the increased risk to the ISS from these visiting vehicles. At the time, only the Shuttle, the Soyuz, and the Progress vehicles rendezvoused and docked to the ISS. The increased risk to the ISS was from an increase in vehicle traffic, thereby, increasing the potential catastrophic collision during the rendezvous and the docking or berthing of the spacecraft to the ISS. A universal method of evaluating the risk of rendezvous and docking or berthing was created by the ISS s Risk Team to accommodate the increasing number of rendezvous and docking or berthing operations due to the increasing number of different spacecraft, as well as the future arrival of commercial spacecraft. Before the first docking attempt of ESA's ATV and JAXA's HTV to the ISS, a probabilistic risk model was developed to quantitatively calculate the risk of collision of each spacecraft with the ISS. The 5 rendezvous and docking risk models (Soyuz, Progress, Shuttle, ATV, and HTV) have been used to build and refine the modeling methodology for rendezvous and docking of spacecrafts. This risk modeling methodology will be NASA s basis for evaluating the addition of future ISS visiting spacecrafts hazards, including SpaceX s Dragon, Orbital Science s Cygnus, and NASA s own Orion spacecraft. This paper will describe the methodology used for developing a visiting vehicle risk model.

  4. NASA Advisory Council Task Force on the Shuttle-Mir Rendezvous and Docking Missions

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The NASA Advisory Council Task Force on the Shuttle-Mir rendezvous and docking convened on May 24 and 25, 1994. Based on the meetings, the Task Force made the following recommendations: at a minimum, the mission commander and payload commander for all subsequent Shuttle-Mir missions should be named at least 18 months in advance of the scheduled launch date; in order to derive early operational experience in advance of the first Mir docking mission, the primary objective of STS-63 should be Mir rendezvous and proximity operations; and if at all possible, the launch date for STS-63 should be moved forward.

  5. Halley comet rendezvous with a SEPS vehicle. [Solar Electric Propulsion System

    NASA Technical Reports Server (NTRS)

    Burrows, R. R.

    1978-01-01

    An analysis of the performance of a Solar Electric Propulsion System (SEPS) vehicle rendezvousing with Halley's comet just prior to its Frebruary 1986 perihelion is described. A calculus of variations mathematical formulation is used to maximize Halley arrival mass while giving effect to the influence of solar array size, launch date, arrival date, and insertion hyperbolic excess velocity. Numerical sensitivity relief, thrust system modeling, trajectory characteristics and ion engine operating conditions are discussed and illustrated. Results indicate a rendezvous is feasible with a minimal advance in solar cell and ion engine technology.

  6. A Comparison of Trajectory Optimization Methods for the Impulsive Minimum Fuel Rendezvous Problem

    NASA Technical Reports Server (NTRS)

    Hughes, Steven P.; Mailhe, Laurie M.; Guzman, Jose J.

    2002-01-01

    In this paper we present a comparison of optimization approaches to the minimum fuel rendezvous problem. Both indirect and direct methods are compared for a variety of test cases. The indirect approach is based on primer vector theory. The direct approaches are implemented numerically and include Sequential Quadratic Programming (SQP), Quasi-Newton, Simplex, Genetic Algorithms, and Simulated Annealing. Each method is applied to a variety of test cases including, circular to circular coplanar orbits, LEO to GEO, and orbit phasing in highly elliptic orbits. We also compare different constrained optimization routines on complex orbit rendezvous problems with complicated, highly nonlinear constraints.

  7. Randomly curved runs interrupted by tumbling: A model for bacterial motion

    NASA Astrophysics Data System (ADS)

    Condat, C. A.; Jäckle, J.; Menchón, S. A.

    2005-08-01

    Small bacteria are strongly buffeted by Brownian forces that make completely straight runs impossible. A model for bacterial motion is formulated in which the effects of fluctuational forces and torques on the run phase are taken into account by using coupled Langevin equations. An integrated description of the motion, including runs and tumbles, is then obtained by the use of convolution and Laplace transforms. The properties of the velocity-velocity correlation function, of the mean displacement, and of the two relevant diffusion coefficients are examined in terms of the bacterial sizes and of the magnitude of the propelling forces. For bacteria smaller than E. coli, the integrated diffusion coefficient crosses over from a jump-dominated to a rotational-diffusion-dominated form.

  8. Recent developments in electropolishing and tumbling R&D at Fermilab

    SciTech Connect

    Cooper, C.; Brandt, J.; Cooley, L.; Ge, M.; Harms, E.; Khabiboulline, T.; Ozelis, J.; Boffo, C.; /Babcock Noell, Wuerzburg

    2009-10-01

    Fermi National Accelerator Lab (Fermilab) is continuing to improve its infrastructure for research and development on the processing of superconducting radio frequency cavities. A single cell 3.9 GHz electropolishing tool built at Fermilab and operated at an industrial partner was recently commissioned. The EP tool was used to produce a single cell 3.9 GHz cavity that reached an accelerating gradient of 30 MV/m with a quality factor of 5 x 10{sup 9}. A single cell 1.3 GHz cavity was also electropolished at the same industrial vendor using the vendor's vertical full-immersion technique. On their first and only attempt the vendor produced a single cell 1.3 GHz cavity that reached 30 MV/m with a quality factor of 1 x 10{sup 10}. These results will be detailed along with preliminary tumbling results.

  9. On the distribution and swim pressure of run-and-tumble particles in confinement

    NASA Astrophysics Data System (ADS)

    Ezhilan, Barath; Alonso-Matilla, Roberto; Saintillan, David

    2015-10-01

    The spatial and orientational distribution in a dilute active suspension of non-Brownian run-and-tumble spherical swimmers confined between two planar hard walls is calculated theoretically. Using a kinetic model based on coupled bulk/surface probability density functions, we demonstrate the existence of a concentration wall boundary layer with thickness scaling with the run length, the absence of polarization throughout the channel, and the presence of sharp discontinuities in the bulk orientation distribution in the neighborhood of orientations parallel to the wall in the near-wall region. Our model is also applied to calculate the swim pressure in the system, which approaches the previously proposed ideal-gas behavior in wide channels but is found to decrease in narrow channels as a result of confinement. Monte-Carlo simulations are also performed for validation and show excellent quantitative agreement with our theoretical predictions.

  10. Rendezvous and Docking Strategy for Crewed Segment of the Asteroid Redirect Mission

    NASA Technical Reports Server (NTRS)

    Hinkel, Heather D.; Cryan, Scott P.; D'Souza, Christopher; Dannemiller, David P.; Brazzel, Jack P.; Condon, Gerald L.; Othon, William L.; Williams, Jacob

    2014-01-01

    This paper will describe the overall rendezvous, proximity operations and docking (RPOD) strategy in support of the Asteroid Redirect Crewed Mission (ARCM), as part of the Asteroid Redirect Mission (ARM). The focus of the paper is on the crewed mission phase of ARM, starting with the establishment of Orion in the Distant Retrograde Orbit (DRO) and ending with docking to the Asteroid Redirect Vechicle (ARV). The paper will detail the sequence of maneuvers required to execute the rendezvous and proximity operations mission phases along with the on-board navigation strategies, including the final approach phase. The trajectories to be considered will include target vehicles in a DRO. The paper will also discuss the sensor requirements for rendezvous and docking and the various trade studies associated with the final sensor selection. Building on the sensor requirements and trade studies, the paper will include a candidate sensor concept of operations, which will drive the selection of the sensor suite; concurrently, it will be driven by higher level requirements on the system, such as crew timeline constraints and vehicle consummables. This paper will address how many of the seemingly competing requirements will have to be addressed to create a complete system and system design. The objective is to determine a sensor suite and trajectories that enable Orion to successfully rendezvous and dock with a target vehicle in trans lunar space. Finally, the paper will report on the status of a NASA action to look for synergy within RPOD, across the crewed and robotic asteroid missions.

  11. Rendez-vous de Concarneau, where industry meets science in marine biotechnology

    E-print Network

    employed (fishermen excluded) Rendez-vous de Concarneau 2015/10/16 An economy strongly linked to the ocean rather than sponge diversity Van Soest & al., Global diversity of sponges, PLOS one, april 2012 French 45 000 20 000 20 000 120 000 85 000 Region funding 25 000 Prospection x x Identification x x

  12. Multiple Agents RendezVous In a Ring in Spite of a Black Hole

    E-print Network

    Santoro, Nicola

    Multiple Agents RendezVous In a Ring in Spite of a Black Hole Stefan Dobrev Paola Flocchini this problem when in the network there is a black hole: a stationary process located at a node that destroys any incoming agent without leaving any trace. The presence of the black hole makes it clearly

  13. Peer-to-Peer Refuelling within a Satellite Constellation Part II: Nonzero-Cost Rendezvous Case

    E-print Network

    Tsiotras, Panagiotis

    Peer-to-Peer Refuelling within a Satellite Constellation Part II: Nonzero-Cost Rendezvous Case in a constellation. It is assumed that there is no fuel delivered to the constellation externally. Instead, the satellites in the constellation are assumed to be capable of refuelling each other. The cost

  14. Peer-to-Peer Refuelling within a Satellite Constellation Part I: Zero-Cost Rendezvous Case

    E-print Network

    Tsiotras, Panagiotis

    Peer-to-Peer Refuelling within a Satellite Constellation Part I: Zero-Cost Rendezvous Case Haijun in a constellation. The satellites in the constellation are assumed to be capable of refu- elling each other in the constellation after a given period. It is shown that the problem of equalizing the fuel among the satellites can

  15. Multi-robot SLAM with Unknown Initial Correspondence: The Robot Rendezvous Case

    E-print Network

    Roumeliotis, Stergios I.

    that enables teams of robots to build joint maps without initial knowledge of their relative poses. The keyMulti-robot SLAM with Unknown Initial Correspondence: The Robot Rendezvous Case Xun S. Zhou, MN Abstract-- This paper presents a new approach to the multi- robot map-alignment problem

  16. Sensory fusion for planetary surface robotic navigation, rendezvous, and manipulation operations

    NASA Technical Reports Server (NTRS)

    Huntsberger, T.; Cheng, Y.; Baumgartner, E. T.; Robinson, M.; Schenker, P. S.

    2003-01-01

    This paper reports some of the ongoing work at JPL in the areas of autonomous sensory fusion of both raw and derived inputs for better localization during long traverses, precision rendezvous operations with both labeled and unlabeled targets, and precision manipulation of targets.

  17. Methodology for Prototyping Increased Levels of Automation for Spacecraft Rendezvous Functions

    NASA Technical Reports Server (NTRS)

    Hart, Jeremy J.; Valasek, John

    2007-01-01

    The Crew Exploration Vehicle necessitates higher levels of automation than previous NASA vehicles, due to program requirements for automation, including Automated Rendezvous and Docking. Studies of spacecraft development often point to the locus of decision-making authority between humans and computers (i.e. automation) as a prime driver for cost, safety, and mission success. Therefore, a critical component in the Crew Exploration Vehicle development is the determination of the correct level of automation. To identify the appropriate levels of automation and autonomy to design into a human space flight vehicle, NASA has created the Function-specific Level of Autonomy and Automation Tool. This paper develops a methodology for prototyping increased levels of automation for spacecraft rendezvous functions. This methodology is used to evaluate the accuracy of the Function-specific Level of Autonomy and Automation Tool specified levels of automation, via prototyping. Spacecraft rendezvous planning tasks are selected and then prototyped in Matlab using Fuzzy Logic techniques and existing Space Shuttle rendezvous trajectory algorithms.

  18. Optimal starting conditions for the rendezvous maneuver: Analytical and computational approach

    NASA Astrophysics Data System (ADS)

    Ciarcia, Marco

    The three-dimensional rendezvous between two spacecraft is considered: a target spacecraft on a circular orbit around the Earth and a chaser spacecraft initially on some elliptical orbit yet to be determined. The chaser spacecraft has variable mass, limited thrust, and its trajectory is governed by three controls, one determining the thrust magnitude and two determining the thrust direction. We seek the time history of the controls in such a way that the propellant mass required to execute the rendezvous maneuver is minimized. Two cases are considered: (i) time-to-rendezvous free and (ii) time-to-rendezvous given, respectively equivalent to (i) free angular travel and (ii) fixed angular travel for the target spacecraft. The above problem has been studied by several authors under the assumption that the initial separation coordinates and the initial separation velocities are given, hence known initial conditions for the chaser spacecraft. In this paper, it is assumed that both the initial separation coordinates and initial separation velocities are free except for the requirement that the initial chaser-to-target distance is given so as to prevent the occurrence of trivial solutions. Two approaches are employed: optimal control formulation (Part A) and mathematical programming formulation (Part B). In Part A, analyses are performed with the multiple-subarc sequential gradient-restoration algorithm for optimal control problems. They show that the fuel-optimal trajectory is zero-bang, namely it is characterized by two subarcs: a long coasting zero-thrust subarc followed by a short powered max-thrust braking subarc. While the thrust direction of the powered subarc is continuously variable for the optimal trajectory, its replacement with a constant (yet optimized) thrust direction produces a very efficient guidance trajectory. Indeed, for all values of the initial distance, the fuel required by the guidance trajectory is within less than one percent of the fuel required by the optimal trajectory. For the guidance trajectory, because of the replacement of the variable thrust direction of the powered subarc with a constant thrust direction, the optimal control problem degenerates into a mathematical programming problem with a relatively small number of degrees of freedom, more precisely: three for case (i) time-to-rendezvous free and two for case (ii) time-to-rendezvous given. In particular, we consider the rendezvous between the Space Shuttle (chaser) and the International Space Station (target). Once a given initial distance SS-to-ISS is preselected, the present work supplies not only the best initial conditions for the rendezvous trajectory, but simultaneously the corresponding final conditions for the ascent trajectory. In Part B, an analytical solution of the Clohessy-Wiltshire equations is presented (i) neglecting the change of the spacecraft mass due to the fuel consumption and (ii) and assuming that the thrust is finite, that is, the trajectory includes powered subarcs flown with max thrust and coasting subarc flown with zero thrust. Then, employing the found analytical solution, we study the rendezvous problem under the assumption that the initial separation coordinates and initial separation velocities are free except for the requirement that the initial chaser-to-target distance is given. The main contribution of Part B is the development of analytical solutions for the powered subarcs, an important extension of the analytical solutions already available for the coasting subarcs. One consequence is that the entire optimal trajectory can be described analytically. Another consequence is that the optimal control problems degenerate into mathematical programming problems. A further consequence is that, vis-a-vis the optimal control formulation, the mathematical programming formulation reduces the CPU time by a factor of order 1000. Key words. Space trajectories, rendezvous, optimization, guidance, optimal control, calculus of variations, Mayer problems, Bolza problems, transformation techniques, multiple-subarc sequenti

  19. Coupling fast water exchange to slow molecular tumbling in Gd3+ chelates: why faster is not always better

    PubMed Central

    Avedano, Stefano; Botta, Mauro; Haigh, Julian S.; Longo, Dario; Woods, Mark

    2013-01-01

    The influence of dynamics on solution state structure is a widely overlooked consideration in chemistry. Variations in Gd3+ chelate hydration with changing coordination geometry and dissociative water exchange kinetics substantially impact the effectiveness (or relaxivity) of mono-hydrated Gd3+ chelates as T1-shortening contrast agents for MRI. Theory shows that relaxivity is highly dependent upon the Gd3+-water proton distance (rGdH) and yet this distance is almost never considered as a variable in assessing the relaxivity of a Gd3+ chelate as a potential contrast agent. The consequence of this omission can be seen when considering the relaxivity of isomeric Gd3+ chelates that exhibit different dissociative water exchange kinetics. The results described herein show that the relaxivity of a chelate with ‘optimal’ dissociative water exchange kinetics is actually lower than that of an isomeric chelate with ‘sub-optimal’ dissociative water exchange. When the rate of molecular tumbling of these chelates is slowed, an approach that has long been understood to increase relaxivity, the observed difference in relaxivity is increased with the more rapidly exchanging (‘optimal’) chelate exhibiting lower relaxivity than the ‘sub-optimally’ exchanging isomer. The difference between the chelates arises from a non-field dependent parameter: either the hydration number (q) or rGdH. For solution state Gd3+ chelates, changes in the values of q and rGdH are indistinguishable. These parametric expressions simply describe the hydration state of the chelate – i.e. the number and position of closely associating water molecules. The hydration state (q/rGdH6) of a chelate is intrinsically linked to its dissociative water exchange rate kex and the interrelation of these parameters must be considered when examining the relaxivity of Gd3+ chelates. The data presented herein indicates that the changes in the hydration parameter (q/rGdH6) associated with changing dissociative water exchange kinetics has a profound effect on relaxivity and suggest that achieving the highest relaxivities in monohydrated Gd3+ chelates is more complicated than simply “optimizing” dissociative water exchange kinetics. PMID:23841587

  20. Assessing the Size, Stability, and Utility of Isotropically Tumbling Bicelle Systems for Structural Biology

    PubMed Central

    Wu, Hongwei; Su, Kai; Guan, Xudong; Sublette, M. Elizabeth; Stark, Ruth E.

    2009-01-01

    Aqueous phospholipid mixtures that form bilayered micelles (bicelles) have gained wide use by molecular biophysicists during the past 20 years for spectroscopic studies of membrane-bound peptides and structural refinement of soluble protein structures. Nonetheless, the utility of bicelle systems may be compromised by considerations of cost, chemical stability, and preservation of the bicelle aggregate organization under a broad range of temperature, concentration, pH, and ionic strength conditions. In the current work, 31P nuclear magnetic resonance (NMR) and atomic force microscopy (AFM) have been used to monitor the size and morphology of isotropically tumbling small bicelles formed by mixtures of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) or 1,2-di-O-tetradecyl-sn-glycero-3-phosphocholine (DIOMPC) with either 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) or 1,2-di-O-hexyl-sn-glycero-3-phospho-choline (DIOHPC), testing their tolerance of variations in commonly used experimental conditions. 1H-15N 2D NMR has been used to demonstrate the usefulness of the robust DMPC-DIOHPC system for conformational studies of a fatty acid-binding protein that shuttles small ligands to and from biological membranes. PMID:19914202

  1. Active Brownian Particles and Run-and-Tumble Particles: a Comparative Study

    E-print Network

    A. P. Solon; M. E. Cates; J. Tailleur

    2015-10-09

    Active Brownian particles (ABPs) and Run-and-Tumble particles (RTPs) both self-propel at fixed speed $v$ along a body-axis ${\\bf u}$ that reorients either through slow angular diffusion (ABPs) or sudden complete randomisation (RTPs). We compare the physics of these two model systems both at microscopic and macroscopic scales. Using exact results for their steady-state distribution in the presence of external potentials, we show that they both admit the same effective equilibrium regime perturbatively that breaks down for stronger external potentials, in a model-dependent way. In the presence of collisional repulsions such particles slow down at high density: their propulsive effort is unchanged, but their average speed along ${\\bf u}$ becomes $v(\\rho) swim at a variable speed $v$ that is an explicit function or functional of the density $\\rho$. We give numerical evidence that the recently shown equivalence of the fluctuating hydrodynamics of ABPs and RTPs in this case, which we detail here, extends to microscopic models of ABPs and RTPs interacting with repulsive forces.

  2. Active brownian particles and run-and-tumble particles: A comparative study

    NASA Astrophysics Data System (ADS)

    Solon, A. P.; Cates, M. E.; Tailleur, J.

    2015-07-01

    Active Brownian particles (ABPs) and Run-and-Tumble particles (RTPs) both self-propel at fixed speed v along a body-axis u that reorients either through slow angular diffusion (ABPs) or sudden complete randomisation (RTPs). We compare the physics of these two model systems both at microscopic and macroscopic scales. Using exact results for their steady-state distribution in the presence of external potentials, we show that they both admit the same effective equilibrium regime perturbatively that breaks down for stronger external potentials, in a model-dependent way. In the presence of collisional repulsions such particles slow down at high density: their propulsive effort is unchanged, but their average speed along u becomes v(?) < v. A fruitful avenue is then to construct a mean-field description in which particles are ghost-like and have no collisions, but swim at a variable speed v that is an explicit function or functional of the density ?. We give numerical evidence that the recently shown equivalence of the fluctuating hydrodynamics of ABPs and RTPs in this case, which we detail here, extends to microscopic models of ABPs and RTPs interacting with repulsive forces.

  3. Tools and Techniques for a Systematic Approach to Safe Rendezvous and Proximity Operations

    NASA Astrophysics Data System (ADS)

    Taylor, Rob; Rishikof, Brian

    2010-09-01

    Among the most demanding operations facing manned spaceflight is the ability to successfully and safely complete Rendezvous Proximity Operations & Capture(RPOC) operations with a target vehicle. While perhaps made to look routine from a safety perspective for some vehicles and developers regularly docking to the International Space Station(namely the Space Shuttle, and Russian Progress and Soyuz vehicles), international partners and commercial vehicle developers are finding it among the most difficult engineering challenges. Whether docking with the International Space Station in low earth orbit, or rendezvousing with a returning spacecraft in low lunar orbit, successfully and systematically accounting for all the combinations of risks and failures which lead to failed rendezvous or collisions can be daunting. Systems such as propulsion, avionics, software, and command and data handling(C&DH) must all work as a single integrated system; and the guidance, navigation, and control(GN&C) systems arguably forms the heart of that unit. In response to this challenge, Odyssey Space Research(Odyssey) utilizes their core GN&C engineering competencies, systems engineering capabilities and associated simulation tools to address the safety of RPOC. These simulations provide for high-level mission scenario analysis, systems design, mission planning, monitoring, and implementation, covering all flight phases of rendezvous from orbit insertion, phasing and transfer orbits, far-range rendezvous operations, proximity operations, and capture. Combined with a systems engineering approach, it allows our team to analyze functional system capabilities, propose design modifications and then perform the safety engineering aspect of evaluating that vehicle’s safety compliance. The simulation, modeling and analysis tools(such as domain specific RPOC models, and visualization and virtual reality) allow for detailed design and development and/or help provide the independent assessment required for verification and validation of adequate operational and safety implementations. Of the design and independent verification and validation(IV&V) capabilities in use, simulations remain the centerpiece. Current, in-house developed simulations provide “plug-and-play” modularized approaches to various spacecraft subsystem analysis combining:(a) open source software development tools,(b) widely used NASA simulation environments(e.g. TRICK),(c) a libraries of reusable vehicle components,(d) onboard data management software components, and(e) hard real time software generation tools. Combining those tools and techniques with proven fault trees and systematic hazard analysis provides the basis for a systematic approach to safe rendezvous and proximity operations.

  4. Guidance and Navigation for Rendezvous and Proximity Operations with a Non-Cooperative Spacecraft at Geosynchronous Orbit

    NASA Technical Reports Server (NTRS)

    Barbee, Brent William; Carpenter, J. Russell; Heatwole, Scott; Markley, F. Landis; Moreau, Michael; Naasz, Bo J.; VanEepoel, John

    2010-01-01

    The feasibility and benefits of various spacecraft servicing concepts are currently being assessed, and all require that the servicer spacecraft perform rendezvous, proximity, and capture operations with the target spacecraft to be serviced. Many high-value spacecraft, which would be logical targets for servicing from an economic point of view, are located in geosynchronous orbit, a regime in which autonomous rendezvous and capture operations are not commonplace. Furthermore, existing GEO spacecraft were not designed to be serviced. Most do not have cooperative relative navigation sensors or docking features, and some servicing applications, such as de-orbiting of a non-functional spacecraft, entail rendezvous and capture with a spacecraft that may be non-functional or un-controlled. Several of these challenges have been explored via the design of a notional mission in which a nonfunctional satellite in geosynchronous orbit is captured by a servicer spacecraft and boosted into super-synchronous orbit for safe disposal. A strategy for autonomous rendezvous, proximity operations, and capture is developed, and the Orbit Determination Toolbox (ODTBX) is used to perform a relative navigation simulation to assess the feasibility of performing the rendezvous using a combination of angles-only and range measurements. Additionally, a method for designing efficient orbital rendezvous sequences for multiple target spacecraft is utilized to examine the capabilities of a servicer spacecraft to service multiple targets during the course of a single mission.

  5. Low-Cost Innovation in Spaceflight: The Near Earth Asteroid Rendezvous (NEAR) Shoemaker Mission

    NASA Technical Reports Server (NTRS)

    McCurdy, Howard E.

    2005-01-01

    On a spring day in 1996, at their research center in the Maryland countryside, representatives from the Johns Hopkins University Applied Physics Laboratory (APL) presented Administrator Daniel S. Goldin of the National Aeronautics and Space Administration (NASA) with a check for $3.6 million. 1 Two and a half years earlier, APL officials had agreed to develop a spacecraft capable of conducting an asteroid rendezvous and to do so for slightly more than $122 million. This was a remarkably low sum for a spacecraft due to conduct a planetaryclass mission. By contrast, the Mars Observer spacecraft launched in 1992 for an orbital rendezvous with the red planet had cost $479 million to develop, while the upcoming Cassini mission to Saturn required a spacecraft whose total cost was approaching $1.4 billion. In an Agency accustomed to cost overruns on major missions, the promise to build a planetary-class spacecraft for about $100 million seemed excessively optimistic.

  6. Relative position and attitude estimation of spacecrafts based on dual quaternion for rendezvous and docking

    NASA Astrophysics Data System (ADS)

    Qiao, Bing; Tang, Shuren; Ma, Kexin; Liu, Zhenya

    2013-10-01

    The capacity to acquire the relative position and attitude information between the chaser and the target satellites in real time is one of the necessary prerequisites for the successful implementation of autonomous rendezvous and docking. This paper addresses a vision based relative position and attitude estimation algorithm for the final phase of spacecraft rendezvous and docking. By assuming that the images of feature points on the target satellite lie within the convex regions, the estimation of the relative position and attitude is converted into solving a convex optimization problem in which the dual quaternion method is employed to represent the rotational and translational transformation between the chaser body frame and the target body frame. Due to the point-to-region correspondence instead of the point-to-point correspondence is used, the proposed estimation algorithm shows good performance in robustness which is verified through computer simulations.

  7. Optimal impulsive time-fixed orbital rendezvous and interception with path constraints

    NASA Technical Reports Server (NTRS)

    Taur, D.-R.; Prussing, J. E.; Coverstone-Carroll, V.

    1990-01-01

    Minimum-fuel, impulsive, time-fixed solutions are obtained for the problem of orbital rendezvous and interception with interior path constraints. Transfers between coplanar circular orbits in an inverse-square gravitational field are considered, subject to a circular path constraint representing a minimum or maximum permissible orbital radius. Primer vector theory is extended to incorporate path constraints. The optimal number of impulses, their times and positions, and the presence of initial or final coasting arcs are determined. The existence of constraint boundary arcs and boundary points is investigated as well as the optimality of a class of singular arc solutions. To illustrate the complexities introduced by path constraints, an analysis is made of optimal rendezvous in field-free space subject to a minimum radius constraint.

  8. Interception, evasion, rendezvous and velocity-to-be-gained guidance for spacecraft

    NASA Astrophysics Data System (ADS)

    Menon, P. K. A.; Calise, A. J.

    Optimal nonlinear feedback guidance laws are derived for a pursuit-evasion differential game between two spacecraft, and for more traditional problems of spacecraft rendezvous and velocity-to-be-gained tasks. The present approach uses complete nonlinear point-mass models for spacecraft and is suitable for on-board implementation. The guidance laws are applicable for large amplitude maneuvers and can account for the presence of more than one gravitational field.

  9. Automated Rendezvous and Docking Sensor Testing at the Flight Robotics Laboratory

    NASA Technical Reports Server (NTRS)

    Mitchell, J.; Johnston, A.; Howard, R.; Williamson, M.; Brewster, L.; Strack, D.; Cryan, S.

    2007-01-01

    The Exploration Systems Architecture defines missions that require rendezvous, proximity operations, and docking (RPOD) of two spacecraft both in Low Earth Orbit (LEO) and in Low Lunar Orbit (LLO). Uncrewed spacecraft must perform automated and/or autonomous rendezvous, proximity operations and docking operations (commonly known as Automated Rendezvous and Docking, AR&D). The crewed versions may also perform AR&D, possibly with a different level of automation and/or autonomy, and must also provide the crew with relative navigation information for manual piloting. The capabilities of the RPOD sensors are critical to the success of the Exploration Program. NASA has the responsibility to determine whether the Crew Exploration Vehicle (CEV) contractor-proposed relative navigation sensor suite will meet the CEV requirements. The relatively low technology readiness of relative navigation sensors for AR&D has been carried as one of the CEV Projects top risks. The AR&D Sensor Technology Project seeks to reduce this risk by increasing technology maturation of selected relative navigation sensor technologies through testing and simulation, and to allow the CEV Project to assess the relative navigation sensors.

  10. Automated Rendezvous and Docking Sensor Testing at the Flight Robotics Laboratory

    NASA Technical Reports Server (NTRS)

    Howard, Richard T.; Williamson, Marlin L.; Johnston, Albert S.; Brewster, Linda L.; Mitchell, Jennifer D.; Cryan, Scott P.; Strack, David; Key, Kevin

    2007-01-01

    The Exploration Systems Architecture defines missions that require rendezvous, proximity operations, and docking (RPOD) of two spacecraft both in Low Earth Orbit (LEO) and in Low Lunar Orbit (LLO). Uncrewed spacecraft must perform automated and/or autonomous rendezvous, proximity operations and docking operations (commonly known as Automated Rendezvous and Docking, (AR&D).) The crewed versions of the spacecraft may also perform AR&D, possibly with a different level of automation and/or autonomy, and must also provide the crew with relative navigation information for manual piloting. The capabilities of the RPOD sensors are critical to the success of the Exploration Program. NASA has the responsibility to determine whether the Crew Exploration Vehicle (CEV) contractor-proposed relative navigation sensor suite will meet the CEV requirements. The relatively low technology readiness of relative navigation sensors for AR&D has been carried as one of the CEV Projects top risks. The AR&D Sensor Technology Project seeks to reduce this risk by increasing technology maturation of selected relative navigation sensor technologies through testing and simulation, and to allow the CEV Project to assess the relative navigation sensors.

  11. The Data Transfer Kit: A geometric rendezvous-based tool for multiphysics data transfer

    SciTech Connect

    Slattery, S. R.; Wilson, P. P. H.; Pawlowski, R. P.

    2013-07-01

    The Data Transfer Kit (DTK) is a software library designed to provide parallel data transfer services for arbitrary physics components based on the concept of geometric rendezvous. The rendezvous algorithm provides a means to geometrically correlate two geometric domains that may be arbitrarily decomposed in a parallel simulation. By repartitioning both domains such that they have the same geometric domain on each parallel process, efficient and load balanced search operations and data transfer can be performed at a desirable algorithmic time complexity with low communication overhead relative to other types of mapping algorithms. With the increased development efforts in multiphysics simulation and other multiple mesh and geometry problems, generating parallel topology maps for transferring fields and other data between geometric domains is a common operation. The algorithms used to generate parallel topology maps based on the concept of geometric rendezvous as implemented in DTK are described with an example using a conjugate heat transfer calculation and thermal coupling with a neutronics code. In addition, we provide the results of initial scaling studies performed on the Jaguar Cray XK6 system at Oak Ridge National Laboratory for a worse-case-scenario problem in terms of algorithmic complexity that shows good scaling on 0(1 x 104) cores for topology map generation and excellent scaling on 0(1 x 105) cores for the data transfer operation with meshes of O(1 x 109) elements. (authors)

  12. A feasibility study of unmanned rendezvous and docking in Mars orbit. Volume 1: Summary

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The technical feasibility of achieving automatic rendezvous and docking in Mars orbit as a part of a surface sample return mission was investigated based on using as much existing Viking '75 Orbiter and Lander hardware as possible. Both 1981 and 1983/84 mission opportunities were considered. The principle result of the study was the definition of a three stage 289 kg Mars Ascent Vehicle (MAV) capable of accepting a 1 kg sample, injecting itself into a 2200 km circular orbit, and rendezvousing with an orbiting spacecraft carrying an earth return vehicle. Conclusions are that with state of the art systems plus limited application of new developments in areas where feasibility has already been demonstrated, e.g., solid rocket motor sterilization, it is possible to land a small ascent vehicle capable of automatically ascending and rendezvousing with a modified Viking '75 orbiter spacecraft. The mission can be flown in 1981 or 1983/84, but a dual launch or a larger launch vehicle than the Viking Titan 3 Centaur, or the use of space storable propellants for Mars orbit injection, would be required in the 1983/84 opportunity.

  13. A Ground Testbed to Advance US Capability in Autonomous Rendezvous and Docking Project

    NASA Technical Reports Server (NTRS)

    D'Souza, Chris

    2014-01-01

    This project will advance the Autonomous Rendezvous and Docking (AR&D) GNC system by testing it on hardware, particularly in a flight processor, with a goal of testing it in IPAS with the Waypoint L2 AR&D scenario. The entire Agency supports development of a Commodity for Autonomous Rendezvous and Docking (CARD) as outlined in the Agency-wide Community of Practice whitepaper entitled: "A Strategy for the U.S. to Develop and Maintain a Mainstream Capability for Automated/Autonomous Rendezvous and Docking in Low Earth Orbit and Beyond". The whitepaper establishes that 1) the US is in a continual state of AR&D point-designs and therefore there is no US "off-the-shelf" AR&D capability in existence today, 2) the US has fallen behind our foreign counterparts particularly in the autonomy of AR&D systems, 3) development of an AR&D commodity is a national need that would benefit NASA, our commercial partners, and DoD, and 4) an initial estimate indicates that the development of a standardized AR&D capability could save the US approximately $60M for each AR&D project and cut each project's AR&D flight system implementation time in half.

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

    NASA Technical Reports Server (NTRS)

    D'Souza, Christopher; Milenkovich, Zoran; Wilson, Zachary; Huich, David; Bendle, John; Kibler, Angela

    2011-01-01

    The Space Operations Simulation Center (SOSC) at the Lockheed Martin (LM) Waterton Campus in Littleton, Colorado is a dynamic test environment focused on Autonomous Rendezvous and Docking (AR&D) development testing and risk reduction activities. The SOSC supports multiple program pursuits and accommodates testing Guidance, Navigation, and Control (GN&C) algorithms for relative navigation, hardware testing and characterization, as well as software and test process development. The SOSC consists of a high bay (60 meters long by 15.2 meters wide by 15.2 meters tall) with dual six degree-of-freedom (6DOF) motion simulators and a single fixed base 6DOF robot. The large testing area (maximum sensor-to-target effective range of 60 meters) allows for large-scale, flight-like simulations of proximity maneuvers and docking events. The facility also has two apertures for access to external extended-range outdoor target test operations. In addition, the facility contains four Mission Operations Centers (MOCs) with connectivity to dual high bay control rooms and a data/video interface room. The high bay is rated at Class 300,000 (. 0.5 m maximum particles/m3) cleanliness and includes orbital lighting simulation capabilities.

  15. Effect of field size, head motion, and rotational velocity on roll vection and illusory self-tilt in a tumbling room

    NASA Technical Reports Server (NTRS)

    Allison, R. S.; Howard, I. P.; Zacher, J. E.; Oman, C. M. (Principal Investigator)

    1999-01-01

    The effect of field size, velocity, and visual fixation upon the perception of self-body rotation and tilt was examined in a rotating furnished room. Subjects sat in a stationary chair in the furnished room which could be rotated about the body roll axis. For full-field conditions, complete 360 degrees body rotation (tumbling) was the most common sensation (felt by 80% of subjects). Constant tilt or partial tumbling (less than 360 degrees rotation) occurred more frequently with a small field of view (20 deg). The number of subjects who experienced complete tumbling increased with increases in field of view and room velocity (for velocities between 15 and 30 degrees s-1). The speed of perceived self-rotation relative to room rotation also increased with increasing field of view.

  16. Third Report of the Task Force on the Shuttle-Mir Rendezvous and Docking Missions

    NASA Technical Reports Server (NTRS)

    1994-01-01

    In May 1994, the Task Force on the Shuttle-Mir Rendezvous and Docking Missions was established by the NASA Advisory Council. Its purpose is to review Phase 1 (Shuttle-Mir) planning, training, operations, rendezvous and docking, and management and to provide interim reports containing specific recommendations to the Advisory Council. Phase 1 represents the building block to create the experience and technical expertise for an International Space Station. The Phase 1 program brings together the United States and Russia in a major cooperative and contractual program that takes advantage of both countries' capabilities. The content of the Phase 1 program consists of the following elements as defined by the Phase 1 Program Management Plan, dated October 6, 1994: Shuttle-Mir rendezvous and docking missions; astronaut long duration presence on Mir Requirements for Mir support of Phase 1 when astronauts are not on board; outfitting Spektr and Priroda modules with NASA science, research, and risk mitigation equipment Related ground support requirements of NASA and the Russian Space Agency (RSA) to support Phase 1 Integrated NASA and RSA launch schedules and manifests The first meeting of the Task Force was held at the Johnson Space Center (JSC) on May 24 and 25, 1994 with a preliminary report submitted to the NASA Advisory Council on June 6, 1994. The second meeting of the Task Force was held at JSC on July 12 and 13, 1994 and a detailed report containing a series of specific recommendations was submitted on July 29, 1994. This report reflects the results of the third Task Force meeting which was held at JSC on 11 and 12 October, 1994. The briefings presented at that meeting reviewed NASA's response to the Task Force recommendations made to date and provided background data and current status on several critical areas which the Task Force had not addressed in its previous reports.

  17. SPARTAN: A High-Fidelity Simulation for Automated Rendezvous and Docking Applications

    NASA Technical Reports Server (NTRS)

    Turbe, Michael A.; McDuffie, James H.; DeKock, Brandon K.; Betts, Kevin M.; Carrington, Connie K.

    2007-01-01

    bd Systems (a subsidiary of SAIC) has developed the Simulation Package for Autonomous Rendezvous Test and ANalysis (SPARTAN), a high-fidelity on-orbit simulation featuring multiple six-degree-of-freedom (6DOF) vehicles. SPARTAN has been developed in a modular fashion in Matlab/Simulink to test next-generation automated rendezvous and docking guidance, navigation,and control algorithms for NASA's new Vision for Space Exploration. SPARTAN includes autonomous state-based mission manager algorithms responsible for sequencing the vehicle through various flight phases based on on-board sensor inputs and closed-loop guidance algorithms, including Lambert transfers, Clohessy-Wiltshire maneuvers, and glideslope approaches The guidance commands are implemented using an integrated translation and attitude control system to provide 6DOF control of each vehicle in the simulation. SPARTAN also includes high-fidelity representations of a variety of absolute and relative navigation sensors that maybe used for NASA missions, including radio frequency, lidar, and video-based rendezvous sensors. Proprietary navigation sensor fusion algorithms have been developed that allow the integration of these sensor measurements through an extended Kalman filter framework to create a single optimal estimate of the relative state of the vehicles. SPARTAN provides capability for Monte Carlo dispersion analysis, allowing for rigorous evaluation of the performance of the complete proposed AR&D system, including software, sensors, and mechanisms. SPARTAN also supports hardware-in-the-loop testing through conversion of the algorithms to C code using Real-Time Workshop in order to be hosted in a mission computer engineering development unit running an embedded real-time operating system. SPARTAN also contains both runtime TCP/IP socket interface and post-processing compatibility with bdStudio, a visualization tool developed by bd Systems, allowing for intuitive evaluation of simulation results. A description of the SPARTAN architecture and capabilities is provided, along with details on the models and algorithms utilized and results from representative missions.

  18. Embedded Relative Navigation Sensor Fusion Algorithms for Autonomous Rendezvous and Docking Missions

    NASA Technical Reports Server (NTRS)

    DeKock, Brandon K.; Betts, Kevin M.; McDuffie, James H.; Dreas, Christine B.

    2008-01-01

    bd Systems (a subsidiary of SAIC) has developed a suite of embedded relative navigation sensor fusion algorithms to enable NASA autonomous rendezvous and docking (AR&D) missions. Translational and rotational Extended Kalman Filters (EKFs) were developed for integrating measurements based on the vehicles' orbital mechanics and high-fidelity sensor error models and provide a solution with increased accuracy and robustness relative to any single relative navigation sensor. The filters were tested tinough stand-alone covariance analysis, closed-loop testing with a high-fidelity multi-body orbital simulation, and hardware-in-the-loop (HWIL) testing in the Marshall Space Flight Center (MSFC) Flight Robotics Laboratory (FRL).

  19. Orbit Modification of Earth-Crossing Asteroids/Comets Using Rendezvous Spacecraft and Laser Ablation

    NASA Technical Reports Server (NTRS)

    Park, Sang-Young; Mazanek, Daniel D.

    2005-01-01

    This report describes the approach and results of an end-to-end simulation to deflect a long-period comet (LPC) by using a rapid rendezvous spacecraft and laser ablation system. The laser energy required for providing sufficient deflection DELTA V and an analysis of possible intercept/rendezvous spacecraft trajectories are studied in this analysis. These problems minimize a weighted sum of the flight time and required propellant by using an advanced propulsion system. The optimal thrust-vector history and propellant mass to use are found in order to transfer a spacecraft from the Earth to a targeted celestial object. One goal of this analysis is to formulate an optimization problem for intercept/rendezvous spacecraft trajectories. One approach to alter the trajectory of the object in a highly controlled manner is to use pulsed laser ablative propulsion. A sufficiently intense laser pulse ablates the surface of a near-Earth object (NEO) by causing plasma blowoff. The momentum change from a single laser pulse is very small. However, the cumulative effect is very effective because the laser can interact with the object over long periods of time. The laser ablation technique can overcome the mass penalties associated with other nondisruptive approaches because no propellant is required to generate the DELTA V (the material of the celestial object is the propellant source). Additionally, laser ablation is effective against a wide range of surface materials and does not require any landing or physical attachment to the object. For diverting distant asteroids and comets, the power and optical requirements of a laser ablation system on or near the Earth may be too extreme to contemplate in the next few decades. A hybrid solution would be for a spacecraft to carry a laser as a payload to a particular celestial body. The spacecraft would require an advanced propulsion system capable of rapid rendezvous with the object and an extremely powerful electrical generator, which is likely needed for the propulsion system as well. The spacecraft would station-keep with the object at a small standoff distance while the laser ablation is performed.

  20. NASA Automated Rendezvous and Capture Review. A compilation of the abstracts

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This document presents a compilation of abstracts of papers solicited for presentation at the NASA Automated Rendezvous and Capture Review held in Williamsburg, VA on November 19-21, 1991. Due to limitations on time and other considerations, not all abstracts could be presented during the review. The organizing committee determined however, that all abstracts merited availability to all participants and represented data and information reflecting state-of-the-art of this technology which should be captured in one document for future use and reference. The organizing committee appreciates the interest shown in the review and the response by the authors in submitting these abstracts.

  1. A study of central cryogenic cooling system for the comet rendezvous spacecraft

    NASA Technical Reports Server (NTRS)

    Salazar, R. P.; Metzger, A. E.; Wu, Y. C.; Malcolm, J.

    1981-01-01

    Several science instruments required temperatures between 100 K and 120 K on a proposed Halley Flyby, Tempel-2 Rendezvous Mission. Significant features of the thermal environment are a large variation in heliocentric as well as comet distance, very large solar panels for a Solar Electric Propulsion stage, and the comet dust environment. The best cooling is achieved by one central radiative cooler connected by insulated cryogenic heat pipes to the instruments. The conceptual design is of a single-stage rectangular shielded radiator deployed on a boom some distance from the spacecraft bus and solar panels. Thermal modeling determined sensitivity to solar and comet distance and was used to optimize cooler geometry.

  2. Saturn ring rendezvous mission utilizing a tethered sub-satellite

    NASA Technical Reports Server (NTRS)

    Bright, Larry E.

    1990-01-01

    By combining the advanced technologies of constant-thrust propulsion and space tethers in a planetary mission, it may be feasible to perform a complete radial and azimuthal survey of the Saturnian ring system from close range (about 10 km) in a period of some 300 days. Constant-thrust propulsion would provide the means of 'hovering' above the rings while simultaneously spiraling radially inward toward Saturn. Use of a tethered sub-satellite at a distance of 500-1000 km from the main spacecraft would permit an instrumented package to achieve a significant azimuthal angular rate relative to the rings. Exhaustive 360 deg azimuthal mapping at one or two selected distances from Saturn could be performed in a few tens of days.

  3. Study on Performance of Integration Control by Man and Machine in Stage of Final Approaching for Spaceship Rendezvous and Docking

    NASA Astrophysics Data System (ADS)

    Zhou, Qianxiang; Liu, Zhongqi

    With the development of manned space technology, space rendezvous and docking (RVD) technology will play a more and more important role. The astronauts’ participation in a final close period of man-machine combination control is an important way of RVD technology. Spacecraft RVD control involves control problem of a total of 12 degrees of freedom (location) and attitude which it relative to the inertial space the orbit. Therefore, in order to reduce the astronauts’ operation load and reduce the security requirements to the ground station and achieve an optimal performance of the whole man-machine system, it is need to study how to design the number of control parameters of astronaut or aircraft automatic control system. In this study, with the laboratory conditions on the ground, a method was put forward to develop an experimental system in which the performance evaluation of spaceship RVD integration control by man and machine could be completed. After the RVD precision requirements were determined, 26 male volunteers aged 20-40 took part in the performance evaluation experiments. The RVD integration control success rates and total thruster ignition time were chosen as evaluation indices. Results show that if less than three RVD parameters control tasks were finished by subject and the rest of parameters control task completed by automation, the RVD success rate would be larger than eighty-eight percent and the fuel consumption would be optimized. In addition, there were two subjects who finished the whole six RVD parameters control tasks by enough train. In conclusion, if the astronauts' role should be integrated into the RVD control, it was suitable for them to finish the heading, pitch and roll control in order to assure the man-machine system high performance. If astronauts were needed to finish all parameter control, two points should be taken into consideration, one was enough fuel and another was enough long operation time.

  4. Proximity Operations Nano-Satellite Flight Demonstration (PONSFD) Rendezvous Proximity Operations Design and Trade Studies

    NASA Astrophysics Data System (ADS)

    Griesbach, J.; Westphal, J. J.; Roscoe, C.; Hawes, D. R.; Carrico, J. P.

    2013-09-01

    The Proximity Operations Nano-Satellite Flight Demonstration (PONSFD) program is to demonstrate rendezvous proximity operations (RPO), formation flying, and docking with a pair of 3U CubeSats. The program is sponsored by NASA Ames via the Office of the Chief Technologist (OCT) in support of its Small Spacecraft Technology Program (SSTP). The goal of the mission is to demonstrate complex RPO and docking operations with a pair of low-cost 3U CubeSat satellites using passive navigation sensors. The program encompasses the entire system evolution including system design, acquisition, satellite construction, launch, mission operations, and final disposal. The satellite is scheduled for launch in Fall 2015 with a 1-year mission lifetime. This paper provides a brief mission overview but will then focus on the current design and driving trade study results for the RPO mission specific processor and relevant ground software. The current design involves multiple on-board processors, each specifically tasked with providing mission critical capabilities. These capabilities range from attitude determination and control to image processing. The RPO system processor is responsible for absolute and relative navigation, maneuver planning, attitude commanding, and abort monitoring for mission safety. A low power processor running a Linux operating system has been selected for implementation. Navigation is one of the RPO processor's key tasks. This entails processing data obtained from the on-board GPS unit as well as the on-board imaging sensors. To do this, Kalman filters will be hosted on the processor to ingest and process measurements for maintenance of position and velocity estimates with associated uncertainties. While each satellite carries a GPS unit, it will be used sparsely to conserve power. As such, absolute navigation will mainly consist of propagating past known states, and relative navigation will be considered to be of greater importance. For relative observations, each spacecraft hosts 3 electro-optical sensors dedicated to imaging the companion satellite. The image processor will analyze the images to obtain estimates for range, bearing, and pose, with associated rates and uncertainties. These observations will be fed to the RPO processor's relative Kalman filter to perform relative navigation updates. This paper includes estimates for expected navigation accuracies for both absolute and relative position and velocity. Another key task for the RPO processor is maneuver planning. This includes automation to plan maneuvers to achieve a desired formation configuration or trajectory (including docking), as well as automation to safely react to potentially dangerous situations. This will allow each spacecraft to autonomously plan fuel-efficient maneuvers to achieve a desired trajectory as well as compute adjustment maneuvers to correct for thrusting errors. This paper discusses results from a trade study that has been conducted to examine maneuver targeting algorithms required on-board the spacecraft. Ground software will also work in conjunction with the on-board software to validate and approve maneuvers as necessary.

  5. A novel approach to heat transfer enhancement using trapezoid shaped spiral strips to promote tumble and swirl in a slot shaped channel used in heat exchangers 

    E-print Network

    Segura, D.; Acharya, S.

    2012-01-01

    Heat transfer results for a given slot shaped channel with a 3:1 aspect ratio are presented using various configurations of a trapezoid shaped spiral wound strips to enhance swirl and tumble motion in the channel. The Reynolds numbers investigated...

  6. Androgen and the Development of Human Sex-Typical Behavior: Rough-and-Tumble Play and Sex of Preferred Playmates in Children with Congenital Adrenal Hyperplasia (CAH).

    ERIC Educational Resources Information Center

    Hines, Melissa; Kaufman, Francine R.

    1994-01-01

    Examined the rough-and-tumble play and gender of preferred playmates in three- to eight-year olds with congenital adrenal hyperplasia (CAH)--hypothesized to masculinize behaviors that show sex differences--and in unaffected three- to eight-year-old relatives. Found that CAH girls did not exhibit increased levels of masculine behavior when compared…

  7. Relationships between sensory perception and water distribution determined by low-field NMR T(2) relaxation in processed pork - impact of tumbling and RN(-) allele.

    PubMed

    Hullberg, Anja; Bertram, Hanne C

    2005-04-01

    The relationships between water distribution, measured with low-field NMR (LF-NMR) transverse (T(2)) relaxometry and sensory properties in tumbled and non-tumbled cured-smoked loins from 30 female Hampshire crossbred pigs were investigated. Upon distributed analysis of the T(2) relaxation, three populations centred at about 2, 40 and 600-800 ms, respectively, were detected. Clear differences in the characteristics of the intermediate population (T(21)) were observed between loins from carriers and non-carriers of the RN(-) allele, which implies differences in water-protein interactions between the two genotypes. PLS regressions between NMR T(2) variables and sensory attributes revealed significant correlations between NMR T(2) variables and the sensory attributes juiciness, acidulous taste and meat taste, which mainly could be ascribed to the T(21) time constant. In addition, the number of unappealing pores assessed by the sensory panel was highly related to the relative T(2) populations, implying that the microstructure is directly reflected in the NMR T(2) populations. However, prediction of the processing yield from NMR T(2) variables was poor. The correlation improved when RN genotypes and tumbling conditions were included as predictors. Thus, other effects of tumbling treatments and RN genotypes unrelated to NMR T(2) relaxation were observed. PMID:22063149

  8. An integrated autonomous rendezvous and docking system architecture using Centaur modern avionics

    NASA Astrophysics Data System (ADS)

    Nelson, Kurt

    The avionics system for the Centaur upper stage is in the process of being modernized with the current state-of-the-art in strapdown inertial guidance equipment. This equipment includes an integrated flight control processor with a ring laser gyro based inertial guidance system. This inertial navigation unit (INU) uses two MIL-STD-1750A processors and communicates over the MIL-STD-1553B data bus. Commands are translated into load activation through a Remote Control Unit (RCU) which incorporates the use of solid state relays. Also, a programmable data acquisition system replaces separate multiplexer and signal conditioning units. This modern avionics suite is currently being enhanced through independent research and development programs to provide autonomous rendezvous and docking capability using advanced cruise missile image processing technology and integrated GPS navigational aids. A system concept was developed to combine these technologies in order to achieve a fully autonomous rendezvous, docking, and autoland capability. The current system architecture and the evolution of this architecture using advanced modular avionics concepts being pursued for the National Launch System are discussed.

  9. COMPASS Final Report: Near Earth Asteroids Rendezvous and Sample Earth Returns (NEARER)

    NASA Technical Reports Server (NTRS)

    Oleson, Steven R.; McGuire, Melissa L.

    2009-01-01

    In this study, the Collaborative Modeling for Parametric Assessment of Space Systems (COMPASS) team completed a design for a multi-asteroid (Nereus and 1996 FG3) sample return capable spacecraft for the NASA In-Space Propulsion Office. The objective of the study was to support technology development and assess the relative benefits of different electric propulsion systems on asteroid sample return design. The design uses a single, heritage Orion solar array (SA) (approx.6.5 kW at 1 AU) to power a single NASA Evolutionary Xenon Thruster ((NEXT) a spare NEXT is carried) to propel a lander to two near Earth asteroids. After landing and gathering science samples, the Solar Electric Propulsion (SEP) vehicle spirals back to Earth where it drops off the first sample s return capsule and performs an Earth flyby to assist the craft in rendezvousing with a second asteroid, which is then sampled. The second sample is returned in a similar fashion. The vehicle, dubbed Near Earth Asteroids Rendezvous and Sample Earth Returns (NEARER), easily fits in an Atlas 401 launcher and its cost estimates put the mission in the New Frontier s (NF's) class mission.

  10. An integrated autonomous rendezvous and docking system architecture using Centaur modern avionics

    NASA Technical Reports Server (NTRS)

    Nelson, Kurt

    1991-01-01

    The avionics system for the Centaur upper stage is in the process of being modernized with the current state-of-the-art in strapdown inertial guidance equipment. This equipment includes an integrated flight control processor with a ring laser gyro based inertial guidance system. This inertial navigation unit (INU) uses two MIL-STD-1750A processors and communicates over the MIL-STD-1553B data bus. Commands are translated into load activation through a Remote Control Unit (RCU) which incorporates the use of solid state relays. Also, a programmable data acquisition system replaces separate multiplexer and signal conditioning units. This modern avionics suite is currently being enhanced through independent research and development programs to provide autonomous rendezvous and docking capability using advanced cruise missile image processing technology and integrated GPS navigational aids. A system concept was developed to combine these technologies in order to achieve a fully autonomous rendezvous, docking, and autoland capability. The current system architecture and the evolution of this architecture using advanced modular avionics concepts being pursued for the National Launch System are discussed.

  11. Space Shuttle Guidance, Navigation, and Rendezvous Knowledge Capture Reports. Revision 1

    NASA Technical Reports Server (NTRS)

    Goodman, John L.

    2011-01-01

    This document is a catalog and readers guide to lessons learned, experience, and technical history reports, as well as compilation volumes prepared by United Space Alliance personnel for the NASA/Johnson Space Center (JSC) Flight Dynamics Division.1 It is intended to make it easier for future generations of engineers to locate knowledge capture documentation from the Shuttle Program. The first chapter covers observations on documentation quality and research challenges encountered during the Space Shuttle and Orion programs. The second chapter covers the knowledge capture approach used to create many of the reports covered in this document. These chapters are intended to provide future flight programs with insight that could be used to formulate knowledge capture and management strategies. The following chapters contain descriptions of each knowledge capture report. The majority of the reports concern the Space Shuttle. Three are included that were written in support of the Orion Program. Most of the reports were written from the years 2001 to 2011. Lessons learned reports concern primarily the shuttle Global Positioning System (GPS) upgrade and the knowledge capture process. Experience reports on navigation and rendezvous provide examples of how challenges were overcome and how best practices were identified and applied. Some reports are of a more technical history nature covering navigation and rendezvous. They provide an overview of mission activities and the evolution of operations concepts and trajectory design. The lessons learned, experience, and history reports would be considered secondary sources by historians and archivists.

  12. Endoscopic Sphincterotomy Using the Rendezvous Technique for Choledocholithiasis during Laparoscopic Cholecystectomy: A Case Report.

    PubMed

    Tanaka, Takayuki; Haraguchi, Masashi; Tokai, Hirotaka; Ito, Shinichiro; Kitajima, Masachika; Ohno, Tsuyoshi; Onizuka, Shinya; Inoue, Keiji; Motoyoshi, Yasuhide; Kuroki, Tamotsu; Kanemastu, Takashi; Eguchi, Susumu

    2014-05-01

    A 50-year-old male was examined at another hospital for fever, general fatigue and slight abdominal pain. He was treated with antibiotics and observed. However, his symptoms did not lessen, and laboratory tests revealed liver dysfunction, jaundice and an increased inflammatory response. He was then admitted to our hospital and underwent an abdominal computed tomography scan and magnetic resonance cholangiopancreatography (MRCP), which revealed common bile duct (CBD) stones. He was diagnosed with mild acute cholangitis. As the same time, he was admitted to our hospital and an emergency endoscopic retrograde cholangiopancreatography was performed. Vater papilla opening in the third portion of the duodenum and presence of a peripapillary duodenal diverticulum made it difficult to perform cannulation of the CBD. In addition, MRCP revealed that the CBD was extremely narrow (diameter 5 mm). We therefore performed laparoscopic cholecystectomy and endoscopic sphincterotomy using the rendezvous technique for choledocholithiasis simultaneously rather than laparoscopic CBD exploration. After the operation, the patient was discharged with no complications. Although the rendezvous technique has not been very commonly used because several experts in the technique and a large operating room are required, this technique is a very attractive and effective approach for treating choledocholithiasis, for which endoscopic treatment is difficult. PMID:25298761

  13. Space Shuttle Program: Automatic rendezvous, proximity operations, and capture (category 3)

    NASA Astrophysics Data System (ADS)

    Jackson, William L.; Lee, Roscoe; Eick, Richard E.; Hallstrom, J. V.; Hiers, Harry K.; McManamen, John P.; Olszewski, Oscar W.; Prather, Joseph L.; Rue, D. L.; Zimmer, Karl J.

    The NASA Johnson Space Center is actively pursuing the development and demonstration of capabilities for automatic rendezvous, proximity operations, and capture (AR&C) using the Space Shuttle as the active vehicle. This activity combines the technologies, expertise, tools, and facilities of the JSC Tracking and Communications Division (EE), Navigation, Control and Aeronautics Division (EG), Automation and Robotics Division (ER), and Structures and Mechanics Division (ES) of the Engineering Directorate and the Flight Design and Dynamics Division (DM) of the Mission Operations Directorate. Potential benefits of AR&C include more efficient and repeatable rendezvous, proximity operations, and capture operations; reduced impacts on the target vehicles (e.g., Orbiter RCS plume loads); reduced flight crew work loads; reduced ground support requirements; and reduced operational constraints. This paper documents the current JSC capabilities/tools/facilities for AR&C and describes a proposed plan for a progression of ground demonstrations and flight tests and demonstrations of AR&C capabilities. This plan involves the maturing of existing technologies in tracking and communications; guidance, navigation and control; mechanisms; manipulators; and systems management and integrating them into several evolutionary demonstration stages.

  14. Progress in navigation filter estimate fusion and its application to spacecraft rendezvous

    NASA Technical Reports Server (NTRS)

    Carpenter, J. Russell

    1994-01-01

    A new derivation of an algorithm which fuses the outputs of two Kalman filters is presented within the context of previous research in this field. Unlike other works, this derivation clearly shows the combination of estimates to be optimal, minimizing the trace of the fused covariance matrix. The algorithm assumes that the filters use identical models, and are stable and operating optimally with respect to their own local measurements. Evidence is presented which indicates that the error ellipsoid derived from the covariance of the optimally fused estimate is contained within the intersections of the error ellipsoids of the two filters being fused. Modifications which reduce the algorithm's data transmission requirements are also presented, including a scalar gain approximation, a cross-covariance update formula which employs only the two contributing filters' autocovariances, and a form of the algorithm which can be used to reinitialize the two Kalman filters. A sufficient condition for using the optimally fused estimates to periodically reinitialize the Kalman filters in this fashion is presented and proved as a theorem. When these results are applied to an optimal spacecraft rendezvous problem, simulated performance results indicate that the use of optimally fused data leads to significantly improved robustness to initial target vehicle state errors. The following applications of estimate fusion methods to spacecraft rendezvous are also described: state vector differencing, and redundancy management.

  15. Optimization of maneuvers and resources for the rendezvous of a servicing vehicle to a space station

    NASA Astrophysics Data System (ADS)

    Magne, Jacques; Canu, Richard; Joulot, Antoine

    Addressing the generation of flight scenarios for the rendezvous of a servicing vehicle to a space station, solutions in terms of sequences of maneuvers shall be found that meet a generally complex set of mission constraints while optimizing the needed resources. For the optimization of maneuvers and resources during rendezvous, this paper describes a methodology based on the parametric optimization of a sequence of genetic non-impulsional thrust maneuvers which are defined by the user from a standard catalog, allowing to cope with both translations and rotations. The method uses a reduced gradient algorithm to find an optimal trajectory that meet every mission constraint. Most attention has been paid to the standard of realism in the modeling of the chaser and target dynamics, and in the formalization of the constraints on the approach trajectories; these last ones are defined as the terminal position, the attitude and kinematic capture conditions for berthing or docking, the maximal duration allocated to the approach, path constraints, the propulsive capacities of the chaser and a `safety' constraint, which in other words means that any failure on the chaser during the approach shall result in collision avoiding trajectories or in a mechanical contract to the station within safe limits. The criterion for scenarios optimization can be minimization of propellant consumption or phase duration, or a weighed combination of both. For illustration purpose, example results are given for the final approach of a servicing vehicle to an Earth-pointed space station.

  16. Design and development of guidance navigation and control algorithms for spacecraft rendezvous and docking experimentation

    NASA Astrophysics Data System (ADS)

    Guglieri, Giorgio; Maroglio, Franco; Pellegrino, Pasquale; Torre, Liliana

    2014-01-01

    This paper presents the design of the GNC system of a ground test-bed for spacecraft rendezvous and docking experiments. The test-bed is developed within the STEPS project (Systems and Technologies for Space Exploration). The facility consists of a flat floor and two scaled vehicles, one active chaser and one “semi-active” target. Rendezvous and docking maneuvers are performed floating on the plane with pierced plates as lifting systems. The system is designed to work both with inertial and non-inertial reference frame, receiving signals from navigation sensors as: accelerometers, gyroscopes, laser meter, radio finder and video camera, and combining them with a digital filter. A Proportional-Integrative-Derivative control law and Pulse Width Modulators are used to command the cold gas thrusters of the chaser, and to follow an assigned trajectory with its specified velocity profile. The design and development of the guidance, navigation and control system and its architecture-including the software algorithms-are detailed in the paper, presenting a performance analysis based on a simulated environment. A complete description of the integrated subsystems is also presented.

  17. Use of industrial robots for hardware-in-the-loop simulation of satellite rendezvous and docking

    NASA Astrophysics Data System (ADS)

    Ma, Ou; Flores-Abad, Angel; Boge, Toralf

    2012-12-01

    One of the most challenging and risky operations for spacecraft is to perform rendezvous and docking autonomously in space. To ensure a safe and reliable operation, such a mission must be carefully designed and thoroughly verified before a real space mission can be launched. This paper describes the control strategy for achieving high fidelity contact dynamics simulation of a new, robotics-based, hardware-in-the-loop (HIL) rendezvous and docking simulation facility that uses two industrial robots to physically simulate the 6-DOF dynamic maneuvering of two docking satellites. The facility is capable of physically simulating the final approaching within a 25-meter range and the entire docking/capturing process for a satellite on-orbit servicing mission. The key difficulties of using industrial robots for high-fidelity HIL contact dynamics simulation were found and different solution techniques were investigated in the presented project. An admittance control method was proposed to achieve the goal of making the robots in the HIL simulation process match the impedance of the two docking satellites. Simulation study showed the effectiveness and performance of the proposed solution method.

  18. A Comparison of Trajectory Optimization Methods for the Impulsive Minimum Fuel Rendezvous Problem

    NASA Technical Reports Server (NTRS)

    Hughes, Steven P.; Mailhe, Laurie M.; Guzman, Jose J.

    2003-01-01

    In this paper we present, a comparison of trajectory optimization approaches for the minimum fuel rendezvous problem. Both indirect and direct methods are compared for a variety of test cases. The indirect approach is based on primer vector theory. The direct approaches are implemented numerically and include Sequential Quadratic Programming (SQP). Quasi- Newton and Nelder-Meade Simplex. Several cost function parameterizations are considered for the direct approach. We choose one direct approach that appears to be the most flexible. Both the direct and indirect methods are applied to a variety of test cases which are chosen to demonstrate the performance of each method in different flight regimes. The first test case is a simple circular-to-circular coplanar rendezvous. The second test case is an elliptic-to-elliptic line of apsides rotation. The final test case is an orbit phasing maneuver sequence in a highly elliptic orbit. For each test case we present a comparison of the performance of all methods we consider in this paper.

  19. The Successful Development of an Automated Rendezvous and Capture (AR&C) System for the National Aeronautics and Space Administration

    NASA Technical Reports Server (NTRS)

    Roe, Fred D.; Howard, Richard T.

    2003-01-01

    During the 1990's, the Marshall Space Flight Center (MSFC) conducted pioneering research in the development of an automated rendezvous and capture/docking (AR&C) system for U.S. space vehicles. Development and demonstration of a rendezvous sensor was identified early in the AR&C Program as the critical enabling technology that allows automated proximity operations and docking. A first generation rendezvous sensor, the Video Guidance Sensor (VGS), was developed and successfully flown on STS-87 and STS-95, proving the concept of a video- based sensor. A ground demonstration of the entire system and software was successfully tested. Advances in both video and signal processing technologies and the lessons learned from the two successful flight experiments provided a baseline for the development, by the MSFC, of a new generation of video based rendezvous sensor. The Advanced Video Guidance Sensor (AGS) has greatly increased performance and additional capability for longer-range operation with a new target designed as a direct replacement for existing ISS hemispherical reflectors.

  20. Multi-Agent Deterministic Graph Mapping via Robot Rendezvous Chaohui Gong, Stephen Tully, George Kantor, and Howie Choset

    E-print Network

    Choset, Howie

    hypotheses. I. INTRODUCTION For mobile robots to effectively navigate unknown envi- ronments, a map perception and graph inference. For topological SLAM, when a single robot is mapping a graph-like worldMulti-Agent Deterministic Graph Mapping via Robot Rendezvous Chaohui Gong, Stephen Tully, George

  1. A Summary of the Rendezvous, Proximity Operations, Docking, and Undocking (RPODU) Lessons Learned from the Defense Advanced Research Project Agency (DARPA) Orbital Express (OE) Demonstration System Mission

    NASA Technical Reports Server (NTRS)

    Dennehy, Cornelius J.; Carpenter, James R.

    2011-01-01

    The Guidance, Navigation, and Control (GN&C) Technical Discipline Team (TDT) sponsored Dr. J. Russell Carpenter, a Navigation and Rendezvous Subject Matter Expert (SME) from NASA's Goddard Space Flight Center (GSFC), to provide support to the Defense Advanced Research Project Agency (DARPA) Orbital Express (OE) rendezvous and docking flight test that was conducted in 2007. When that DARPA OE mission was completed, Mr. Neil Dennehy, NASA Technical Fellow for GN&C, requested Dr. Carpenter document his findings (lessons learned) and recommendations for future rendezvous missions resulting from his OE support experience. This report captures lessons specifically from anomalies that occurred during one of OE's unmated operations.

  2. Multi-Sensor Testing for Automated Rendezvous and Docking Sensor Testing at the Flight Robotics Laboratory

    NASA Technical Reports Server (NTRS)

    Brewster, L.; Johnston, A.; Howard, R.; Mitchell, J.; Cryan, S.

    2007-01-01

    The Exploration Systems Architecture defines missions that require rendezvous, proximity operations, and docking (RPOD) of two spacecraft both in Low Earth Orbit (LEO) and in Low Lunar Orbit (LLO). Uncrewed spacecraft must perform automated and/or autonomous rendezvous, proximity operations and docking operations (commonly known as AR&D). The crewed missions may also perform rendezvous and docking operations and may require different levels of automation and/or autonomy, and must provide the crew with relative navigation information for manual piloting. The capabilities of the RPOD sensors are critical to the success of the Exploration Program. NASA has the responsibility to determine whether the Crew Exploration Vehicle (CEV) contractor proposed relative navigation sensor suite will meet the requirements. The relatively low technology readiness level of AR&D relative navigation sensors has been carried as one of the CEV Project's top risks. The AR&D Sensor Technology Project seeks to reduce the risk by the testing and analysis of selected relative navigation sensor technologies through hardware-in-the-loop testing and simulation. These activities will provide the CEV Project information to assess the relative navigation sensors maturity as well as demonstrate test methods and capabilities. The first year of this project focused on a series of"pathfinder" testing tasks to develop the test plans, test facility requirements, trajectories, math model architecture, simulation platform, and processes that will be used to evaluate the Contractor-proposed sensors. Four candidate sensors were used in the first phase of the testing. The second phase of testing used four sensors simultaneously: two Marshall Space Flight Center (MSFC) Advanced Video Guidance Sensors (AVGS), a laser-based video sensor that uses retroreflectors attached to the target vehicle, and two commercial laser range finders. The multi-sensor testing was conducted at MSFC's Flight Robotics Laboratory (FRL) using the FRL's 6-DOF gantry system, called the Dynamic Overhead Target System (DOTS). The target vehicle for "docking" in the laboratory was a mockup that was representative of the proposed CEV docking system, with added retroreflectors for the AVGS. The multi-sensor test configuration used 35 open-loop test trajectories covering three major objectives: (1) sensor characterization trajectories designed to test a wide range of performance parameters; (2) CEV-specific trajectories designed to test performance during CEV-like approach and departure profiles; and (3) sensor characterization tests designed for evaluating sensor performance under more extreme conditions as might be induced during a spacecraft failure or during contingency situations. This paper describes the test development, test facility, test preparations, test execution, and test results of the multi-sensor series of trajectories.

  3. Multi-Sensor Testing for Automated Rendezvous and Docking Sensor Testing at the Flight Robotics Lab

    NASA Technical Reports Server (NTRS)

    Brewster, Linda L.; Howard, Richard T.; Johnston, A. S.; Carrington, Connie; Mitchell, Jennifer D.; Cryan, Scott P.

    2008-01-01

    The Exploration Systems Architecture defines missions that require rendezvous, proximity operations, and docking (RPOD) of two spacecraft both in Low Earth Orbit (LEO) and in Low Lunar Orbit (LLO). Uncrewed spacecraft must perform automated and/or autonomous rendezvous, proximity operations and docking operations (commonly known as AR&D). The crewed missions may also perform rendezvous and docking operations and may require different levels of automation and/or autonomy, and must provide the crew with relative navigation information for manual piloting. The capabilities of the RPOD sensors are critical to the success ofthe Exploration Program. NASA has the responsibility to determine whether the Crew Exploration Vehicle (CEV) contractor-proposed relative navigation sensor suite will meet the requirements. The relatively low technology readiness level of AR&D relative navigation sensors has been carried as one of the CEV Project's top risks. The AR&D Sensor Technology Project seeks to reduce the risk by the testing and analysis of selected relative navigation sensor technologies through hardware-in-the-Ioop testing and simulation. These activities will provide the CEV Project information to assess the relative navigation sensors maturity as well as demonstrate test methods and capabilities. The first year of this project focused on a series of "pathfinder" testing tasks to develop the test plans, test facility requirements, trajectories, math model architecture, simulation platform, and processes that will be used to evaluate the Contractor-proposed sensors. Four candidate sensors were used in the first phase of the testing. The second phase of testing used four sensors simultaneously: two Marshall Space Flight Center (MSFC) Advanced Video Guidance Sensors (AVGS), a laser-based video sensor that uses retroreflectors attached to the target vehicle, and two commercial laser range finders. The multi-sensor testing was conducted at MSFC's Flight Robotics Laboratory (FRL) using the FRL's 6-DOF gantry system, called the Dynamic Overhead Target System (DOTS). The target vehicle for "docking" in the laboratory was a mockup that was representative of the proposed CEV docking system, with added retroreflectors for the AVGS.' The multi-sensor test configuration used 35 open-loop test trajectories covering three major objectives: (l) sensor characterization trajectories designed to test a wide range of performance parameters; (2) CEV-specific trajectories designed to test performance during CEV-like approach and departure profiles; and (3) sensor characterization tests designed for evaluating sensor performance under more extreme conditions as might be induced during a spacecraft failure or during contingency situations. This paper describes the test development, test facility, test preparations, test execution, and test results of the multisensor series oftrajectories

  4. Rendezvous strategy impacts on CTV avionics design, system reliability requirements, and available collision avoidance maneuvers

    NASA Technical Reports Server (NTRS)

    Donovan, William J.; Davis, John E.

    1991-01-01

    Rockwell International is conducting an ongoing program to develop avionics architectures that provide high intrinsic value while meeting all mission objectives. Studies are being conducted to determine alternative configurations that have low life-cycle cost and minimum development risk, and that minimize launch delays while providing the reliability level to assure a successful mission. This effort is based on four decades of providing ballistic missile avionics to the United States Air Force and has focused on the requirements of the NASA Cargo Transfer Vehicle (CTV) program in 1991. During the development of architectural concepts it became apparent that rendezvous strategy issues have an impact on the architecture of the avionics system. This is in addition to the expected impact on propulsion and electrical power duration, flight profiles, and trajectory during approach.

  5. Development of an autonomous video rendezvous and docking system, phase 2

    NASA Technical Reports Server (NTRS)

    Tietz, J. C.; Richardson, T. E.

    1983-01-01

    The critical elements of an autonomous video rendezvous and docking system were built and used successfully in a physical laboratory simulation. The laboratory system demonstrated that a small, inexpensive electronic package and a flight computer of modest size can analyze television images to derive guidance information for spacecraft. In the ultimate application, the system would use a docking aid consisting of three flashing lights mounted on a passive target spacecraft. Television imagery of the docking aid would be processed aboard an active chase vehicle to derive relative positions and attitudes of the two spacecraft. The demonstration system used scale models of the target spacecraft with working docking aids. A television camera mounted on a 6 degree of freedom (DOF) simulator provided imagery of the target to simulate observations from the chase vehicle. A hardware video processor extracted statistics from the imagery, from which a computer quickly computed position and attitude. Computer software known as a Kalman filter derived velocity information from position measurements.

  6. Report of the Task Force on the Shuttle-Mir Rendezvous and Docking Missions

    NASA Technical Reports Server (NTRS)

    1994-01-01

    In October 1992, Russia and the U.S. agreed to conduct a fundamentally new program of human cooperation in space. This original 'Shuttle-Mir' project encompassed combined astronaut-cosmonaut activities on the Shuttle, Soyuz, and Mir spacecraft. At that time, the project was limited to: the STS-60 Shuttle mission, which was completed in February 1994 and carried the first Russian cosmonaut; the planned March 1995 Soyuz 18 launch which will carry a U.S. astronaut to the Mir space station for a three month mission; and the STS-71 Shuttle mission which is scheduled to rendezvous and dock with the Mir space station in June 1995. The Task Force's specific recommendations are given.

  7. Multiple spacecraft rendezvous maneuvers by differential drag and low thrust engines

    NASA Astrophysics Data System (ADS)

    Bevilacqua, Riccardo; Hall, Jason S.; Romano, Marcello

    2010-01-01

    A novel two-phase hybrid controller is proposed to optimize propellant consumption during multiple spacecraft rendezvous maneuvers in Low Earth Orbit. This controller exploits generated differentials in aerodynamic drag on each involved chaser spacecraft to effect a propellant-free trajectory near to the target spacecraft during the first phase of the maneuver, and then uses a fuel optimal control strategy via continuous low-thrust engines to effect a precision dock during the second phase. In particular, by varying the imparted aerodynamic drag force on each of the chaser spacecraft, relative differential accelerations are generated between each chaser and the target spacecraft along two of the three translational degrees of freedom. In order to generate this required differential, each chaser spacecraft is assumed to include a system of rotating flat panels. Additionally, each chaser spacecraft is assumed to have continuous low-thrust capability along the three translational degrees of freedom and full-axis attitude control. Sample simulations are presented to support the validity and robustness of the proposed hybrid controller to variations in the atmospheric density along with different spacecraft masses and ballistic coefficients. Furthermore, the proposed hybrid controller is validated against a complete nonlinear orbital model to include relative navigation errors typical of carrier-phase differential GPS (CDGPS). Limitations of the proposed controller appear relative to the target spacecraft's orbit eccentricity and a general characterization of the atmospheric density. Bounds on these variables are included to provide a framework within which the proposed hybrid controller can effect an extremely low propellant rendezvous of multiple chaser spacecraft to a desired target spacecraft.

  8. A combined open-loop and autonomous search and rendezvous navigation system for the CNES/NASA Mars Premier Orbiter mission

    NASA Technical Reports Server (NTRS)

    Riedel, J. E.; Guinn, J.; Delpech, M.; Dubois, J. B.; Geller, D.; Katchmar, P.

    2003-01-01

    This paper will describe the search methods to be used using the radio and optical observations, and will provide a description of the methods and performance of the autonomous onboard rendezvous navigation system.

  9. Evaluation of GPS position and attitude determination for automated rendezvous and docking missions. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Diprinzio, Marc D.; Tolson, Robert H.

    1994-01-01

    The use of the Global Positioning System for position and attitude determination is evaluated for an automated rendezvous and docking mission. The typical mission scenario involves the chaser docking with the target for resupply or repair purposes, and is divided into three sections. During the homing phase, the chaser utilizes coarse acquisition pseudorange data to approach the target; guidance laws for this stage are investigated. In the second phase, differential carrier phase positioning is utilized. The chaser must maintain a quasiconstant distance from the target, in order to resolve the initial integer ambiguities. Once the ambiguities are determined, the terminal phase is entered, and the rendezvous is completed with continuous carrier phase tracking. Attitude knowledge is maintained in all phases through the use of the carrier phase observable. A Kalman filter is utilized to estimate all states from the noisy measurement data. The effects of selective availability and cycle slips are also investigated.

  10. Opportunity options for rendezvous, flyby and sample return mission to different spectral-type asteroids for the 2015-2025

    NASA Astrophysics Data System (ADS)

    Dong, Qiao; Pingyuan, Cui; Yamin, Wang

    2012-03-01

    The feasible rendezvous, flyby and sample return mission scenario to different spectral-type asteroids for the 2015-2025 are investigated. The emphasis is put on the potential target selection and the design of preliminary interplanetary transfer trajectory in this paper. First, according to different scientific motivations, some potential targets with different spectral-type and physical property are selected. Then, some optimal rendezvous and sample return opportunities for different spectral-type asteroids are presented by using pork-chop plots method and Sequential Quadratic-Programming (SQP) algorithm. In order to reduce the launch energy and total velocity increments for sample return mission, the Earth swingby strategy is used. In addition, the feasible trajectory profiles of flyby and rendezvous with two different spectral-type asteroids in one mission are discussed. A hybrid optimization method combing the Differential Evolution (DE) algorithm and SQP algorithm is introduced as a trajectory design method for the mission. Finally, some important parameters of transfer trajectory are analyzed, which would have a direct impact on the design of spacecraft subsystem, such as communication, power and thermal control subsystem.

  11. Tumbling through a landscape: Evidence of instabilities in high-dimensional moduli spaces

    E-print Network

    Brian Greene; David Kagan; Ali Masoumi; Dhagash Mehta; Erick J. Weinberg; Xiao Xiao

    2013-06-03

    We argue that a generic instability afflicts vacua that arise in theories whose moduli space has large dimension. Specifically, by studying theories with multiple scalar fields we provide numerical evidence that for a generic local minimum of the potential the usual semiclassical bubble nucleation rate, Gamma = A e^{-B}, increases rapidly as function of the number of fields in the theory. As a consequence, the fraction of vacua with tunneling rates low enough to maintain metastability appears to fall exponentially as a function of the moduli space dimension. We discuss possible implications for the landscape of string theory. Notably, if our results prove applicable to string theory, the landscape of metastable vacua may not contain sufficient diversity to offer a natural explanation of dark energy.

  12. An overview of autonomous rendezvous and docking system technology development at General Dynamics

    NASA Astrophysics Data System (ADS)

    Kuenzel, Fred

    The Centaur avionics suite is undergoing a dramatic modernization for the commercial, DoD Atlas and Titan programs. The system has been upgraded to the current state-of-the-art in ring laser gyro inertial sensors and Mil-Std-1750A processor technology. The Cruise Missile avionic system has similarly been evolving for many years. Integration of GPS into both systems has been underway for over five years with a follow-on cruise missile system currently in flight test. Rendezvous and Docking related studies have been conducted for over five years in support of OMV, CTV, and Advanced Upper Stages, as well as several other internal IR&D's. The avionics system and AR&D simulator demonstrated to the SATWG in November 1990 has been upgraded considerably under two IR&D programs in 1991. The Centaur modern avionics system is being flown in block upgrades which started in July of 1990. The Inertial Navigation Unit will fly in November of 1991. The Cruise Missile avionics systems have been fully tested and operationally validated in combat. The integrated AR&D system for space vehicle applications has been under development and testing since 1990. A Joint NASA / GD ARD&L System Test Program is currently being planned to validate several aspects of system performance in three different NASA test facilities in 1992.

  13. The influence of spatial ability and experience on performance during spaceship rendezvous and docking

    PubMed Central

    Du, Xiaoping; Zhang, Yijing; Tian, Yu; Huang, Weifen; Wu, Bin; Zhang, Jingyu

    2015-01-01

    Manual rendezvous and docking (manual RVD) is a challenging space task for astronauts. Previous research showed a correlation between spatial ability and manual RVD skills among participants at early stages of training, but paid less attention to experts. Therefore, this study tried to explore the role of spatial ability in manual RVD skills in two groups of trainees, one relatively inexperienced and the other experienced operators. Additionally, mental rotation has been proven essential in RVD and was tested in this study among 27 male participants, 15 novices, and 12 experts. The participants performed manual RVD tasks in a high fidelity simulator. Results showed that experience moderated the relation between mental rotation ability and manual RVD performance. On one hand, novices with high mental rotation ability tended to perform that RVD task more successfully; on the other hand, experts with high mental rotation ability showed not only no performance advantage in the final stage of the RVD task, but had certain disadvantages in their earlier processes. Both theoretical and practical implications were discussed. PMID:26236252

  14. Coherent Doppler lidar for automated space vehicle rendezvous, stationkeeping and capture

    NASA Technical Reports Server (NTRS)

    Bilbro, James A.

    1991-01-01

    The inherent spatial resolution of laser radar makes ladar or lidar an attractive candidate for Automated Rendezvous and Capture application. Previous applications were based on incoherent lidar techniques, requiring retro-reflectors on the target vehicle. Technology improvements (reduced size, no cryogenic cooling requirement) have greatly enhanced the construction of coherent lidar systems. Coherent lidar permits the acquisition of non-cooperative targets at ranges that are limited by the detection capability rather than by the signal-to-noise ratio (SNR) requirements. The sensor can provide translational state information (range, velocity, and angle) by direct measurement and, when used with any array detector, also can provide attitude information by Doppler imaging techniques. Identification of the target is accomplished by scanning with a high pulse repetition frequency (dependent on the SNR). The system performance is independent of range and should not be constrained by sun angle. An initial effort to characterize a multi-element detection system has resulted in a system that is expected to work to a minimum range of 1 meter. The system size, weight and power requirements are dependent on the operating range; 10 km range requires a diameter of 3 centimeters with overall size at 3 x 3 x 15 to 30 cm, while 100 km range requires a 30 cm diameter.

  15. An overview of autonomous rendezvous and docking system technology development at General Dynamics

    NASA Technical Reports Server (NTRS)

    Kuenzel, Fred

    1991-01-01

    The Centaur avionics suite is undergoing a dramatic modernization for the commercial, DoD Atlas and Titan programs. The system has been upgraded to the current state-of-the-art in ring laser gyro inertial sensors and Mil-Std-1750A processor technology. The Cruise Missile avionic system has similarly been evolving for many years. Integration of GPS into both systems has been underway for over five years with a follow-on cruise missile system currently in flight test. Rendezvous and Docking related studies have been conducted for over five years in support of OMV, CTV, and Advanced Upper Stages, as well as several other internal IR&D's. The avionics system and AR&D simulator demonstrated to the SATWG in November 1990 has been upgraded considerably under two IR&D programs in 1991. The Centaur modern avionics system is being flown in block upgrades which started in July of 1990. The Inertial Navigation Unit will fly in November of 1991. The Cruise Missile avionics systems have been fully tested and operationally validated in combat. The integrated AR&D system for space vehicle applications has been under development and testing since 1990. A Joint NASA / GD ARD&L System Test Program is currently being planned to validate several aspects of system performance in three different NASA test facilities in 1992.

  16. The Ion Propulsion System on NASA's Space Technology 4/Champollion Comet Rendezvous Mission

    NASA Technical Reports Server (NTRS)

    Brophy, John R.; Garner, Charles E.; Weiss, Jeffery M.

    1999-01-01

    The ST4/Champollion mission is designed to rendezvous with and land on the comet Tempel 1 and return data from the first-ever sampling of a comet surface. Ion propulsion is an enabling technology for this mission. The ion propulsion system on ST4 consists of three ion engines each essentially identical to the single engine that flew on the DS1 spacecraft. The ST4 propulsion system will operate at a maximum input power of 7.5 kW (3.4 times greater than that demonstrated on DS1), will produce a maximum thrust of 276 mN, and will provide a total (Delta)V of 11.4 km/s. To accomplish this the propulsion system will carry 385 kg of xenon. All three engines will be operated simultaneously for the first 168 days of the mission. The nominal mission requires that each engine be capable of processing 118 kg. If one engine fails after 168 days, the remaining two engines can perform the mission, but must be capable of processing 160 kg of xenon, or twice the original thruster design requirement. Detailed analyses of the thruster wear-out failure modes coupled with experience from long-duration engine tests indicate that the thrusters have a high probability of meeting the 160-kg throughput requirement.

  17. Fuzzy logic techniques for rendezvous and docking of two geostationary satellites

    NASA Technical Reports Server (NTRS)

    Ortega, Guillermo

    1995-01-01

    Large assemblings in space require the ability to manage rendezvous and docking operations. In future these techniques will be required for the gradual build up of big telecommunication platforms in the geostationary orbit. The paper discusses the use of fuzzy logic to model and implement a control system for the docking/berthing of two satellites in geostationary orbit. The system mounted in a chaser vehicle determines the actual state of both satellites and generates torques to execute maneuvers to establish the structural latching. The paper describes the proximity operations to collocate the two satellites in the same orbital window, the fuzzy guidance and navigation of the chaser approaching the target and the final Fuzzy berthing. The fuzzy logic system represents a knowledge based controller that realizes the close loop operations autonomously replacing the conventional control algorithms. The goal is to produce smooth control actions in the proximity of the target and during the docking to avoid disturbance torques in the final assembly orbit. The knowledge of the fuzzy controller consists of a data base of rules and the definitions of the fuzzy sets. The knowledge of an experienced spacecraft controller is captured into a set of rules forming the Rules Data Base.

  18. Autonomous rendezvous and docking: A commercial approach to on-orbit technology validation

    NASA Technical Reports Server (NTRS)

    Tchoryk, Peter, Jr.; Dobbs, Michael E.; Conrad, David J.; Apley, Dale J.; Whitten, Raymond P.

    1991-01-01

    The Space Automation and Robotics Center (SpARC), a NASA-sponsored Center for the Commercial Development of Space (CCDS), in conjunction with its corporate affiliates, is planning an on-orbit validation of autonomous rendezvous and docking (ARD) technology. The emphasis in this program is to utilize existing technology and commercially available components whenever possible. The primary subsystems that will be validated by this demonstration include GPS receivers for navigation, a video-based sensor for proximity operations, a fluid connector mechanism to demonstrate fluid resupply capability, and a compliant, single-point docking mechanism. The focus for this initial experiment will be expendable launch vehicle (ELV) based and will make use of two residual Commercial Experiment Transporter (COMET) service modules. The first COMET spacecraft will be launched in late 1992 and will serve as the target vehicle. The ARD demonstration will take place in late 1994, after the second COMET spacecraft has been launched. The service module from the second COMET will serve as the chase vehicle.

  19. Rendezvous technique for the treatment of complete common bile duct transection after multiple hepatobiliary surgeries.

    PubMed

    Shin, Seung; Klevan, Ariel; Fernandez, Christopher A; Astudillo, J Andres; Martinez, Jose

    2014-10-01

    Common bile duct (CBD) injury during surgical procedures is a serious complication. Partial injury can usually be managed by a combination of percutaneous and/or endoscopic techniques. However, the management of complete transection of the CBD is very challenging. There are small case series of nonsurgical management of complete CBD transection during laparoscopic cholecystectomy. In this particular case, a 55-year-old female patient had multiple operations because of malignant pheochromocytoma with liver metastases. She developed a complete CBD transection during right hepatectomy. A biloma was managed with image-guided percutaneous drainage. However, both attempts of percutaneous transhepatic cholangiography (PTC) and endoscopic retrograde cholangiopancreatography (ERCP) for CBD stent were unsuccessful, as the native CBD was partially resected during the injury. A rendezvous procedure, in which a guidewire was placed through the distal CBD and into a biloma by ERCP and subsequently snared with PTC, allowed for a biliary-duodenal catheter to be placed successfully and achieve continuity of the patient's biliary tree. PMID:25180777

  20. Three-dimensional location and attitude evaluation for rendezvous and docking operation using a single camera

    NASA Astrophysics Data System (ADS)

    Wang, Zhiling; Losito, S.; Mugnuolo, Raffaele; Pasquariello, Guido

    1993-01-01

    In the automatic rendezvous and docking manoeuvre (RVD) of space activity, determining the 3-D location and attitude between two vehicles is most important. A vision system to perform the docking manipulation in RVD is described in this paper. An improved algorithm is used for calibrating the geometric parameters of a camera fixed on the tracking vehicle off-line. Because the line-off-sight angles of four markers on the target vehicle to the lens center of the camera can be computed according to the optical principle and vector theory, the locations of the vehicle are obtained from the solution for a set of nonlinear equations from the triangular theory. The attitude angles for the vehicles are solved by a translational matrix of target frame to vehicle frame. As the vehicle closes in to the target, sets of markers having different distance intervals or a list of calibration parameters for cameras with different fields of view are selected at the proper moment to improve the situation when at least one of the markers exceeds the field of camera view. The series of experiments is given. The vision system is run on a SUN-4/330 Sparc station system equipped with one image board IT-151 and a CCD TV camera. All software is written in C language.

  1. Autonomous reconfigurable GPS/INS navigation and pointing system for rendezvous and docking

    NASA Technical Reports Server (NTRS)

    Upadhyay, Triveni M.

    1991-01-01

    The briefing describes work using the Global Positioning System to determine position of spacecraft and the development of computer tools to utilize these position determinations to enable autonomous rendezvous. Using GPS data in conjunction with Inertial Navigation Systems (INS) provides the capability for absolute spacecraft navigation, navigation of one spacecraft relative to another, and attitude determination. Some results presented are based on limited observations, though simulation results are documented. A GPS/INS navigation flight experiment could provide a platform for evaluating approaches for autonomous operation and reconfigurability of the navigation and attitude determination subsystem for future space vehicles. Current emphasis is on the development and demonstration of an Onboard Mission Manager (OMM) and a Multi-Mode Navigation Kalman filter. Sensor data will be handed over to the OMM, which will determine the appropriate response and generate commands for the Kalman filter to use to reconfigure itself. Global Positioning System measurements and INS data will be processed in the integrated navigation filter and used to compute errors in position, velocity, and attitude. Inertial Navigation Systems instrument errors (biases, scale factors, etc.) also can be estimated. The OMM then will use a knowledge base to determine appropriate system response. The GPS is good for missions that have attitude pointing accuracy requirements within the 100 to 200 arcsecond range.

  2. Fourth Report of the Task Force on the Shuttle-Mir Rendezvous and Docking Missions

    NASA Technical Reports Server (NTRS)

    1995-01-01

    On December 6, 1994, the NASA Administrator, Mr. Daniel Goldin, requested that Lt. Gen. Thomas P. Stafford, in his role as the Chairman of the NASA Advisory Council Task Force on the Shuttle-Mir Rendezvous and Docking Missions, lead a team composed of several Task Force members and technical advisors' to Russia with the goal of reviewing preparations and readiness for the upcoming international Space Station Phase 1 missions. In his directions to Gen. Stafford, Mr. Goldin requested that the review team focus its initial efforts on safety of flight issues for the following Phase 1A missions: the Soyuz TM-21 mission which will carry U.S. astronaut Dr. Norman Thagard and cosmonauts Lt. Col. Vladimir Dezhurov and Mr. Gennady Strekalov aboard a Soyuz spacecraft to the Mir Station; the Mir 18 Main Expedition during which Thagard and his fellow cosmonauts, Dezhurov and Strokalov, will spend approximately three months aboard the Mir Station; the STS-71 Space Shuttle mission which will perform the first Shuttle-Mir docking, carry cosmonauts Col. Anatoly SoloViev and Mr. Nikolai Budarin to the Mir Station, and return Thagard, Dezhurov, and Strekalov to Earth.

  3. String method for calculation of minimum free-energy paths in Cartesian space in freely-tumbling systems.

    PubMed

    Branduardi, Davide; Faraldo-Gómez, José D

    2013-09-10

    The string method is a molecular-simulation technique that aims to calculate the minimum free-energy path of a chemical reaction or conformational transition, in the space of a pre-defined set of reaction coordinates that is typically highly dimensional. Any descriptor may be used as a reaction coordinate, but arguably the Cartesian coordinates of the atoms involved are the most unprejudiced and intuitive choice. Cartesian coordinates, however, present a non-trivial problem, in that they are not invariant to rigid-body molecular rotations and translations, which ideally ought to be unrestricted in the simulations. To overcome this difficulty, we reformulate the framework of the string method to integrate an on-the-fly structural-alignment algorithm. This approach, referred to as SOMA (String method with Optimal Molecular Alignment), enables the use of Cartesian reaction coordinates in freely tumbling molecular systems. In addition, this scheme permits the dissection of the free-energy change along the most probable path into individual atomic contributions, thus revealing the dominant mechanism of the simulated process. This detailed analysis also provides a physically-meaningful criterion to coarse-grain the representation of the path. To demonstrate the accuracy of the method we analyze the isomerization of the alanine dipeptide in vacuum and the chair-to-inverted-chair transition of ?-D mannose in explicit water. Notwithstanding the simplicity of these systems, the SOMA approach reveals novel insights into the atomic mechanism of these isomerizations. In both cases, we find that the dynamics and the energetics of these processes are controlled by interactions involving only a handful of atoms in each molecule. Consistent with this result, we show that a coarse-grained SOMA calculation defined in terms of these subsets of atoms yields nearidentical minimum free-energy paths and committor distributions to those obtained via a highly-dimensional string. PMID:24729762

  4. Coherent Doppler lidar for automated space vehicle, rendezvous, station-keeping and capture

    NASA Technical Reports Server (NTRS)

    Dunkin, James A.

    1991-01-01

    Recent advances in eye-safe, short wavelength solid-state lasers offer real potential for the development of compact, reliable, light-weight, efficient coherent lidar. Laser diode pumping of these devices has been demonstrated, thereby eliminating the need for flash lamp pumping, which has been a major drawback to the use of these lasers in space based applications. Also these lasers now have the frequency stability required to make them useful in coherent lidar, which offers all of the advantages of non-coherent lidar, but with the additional advantage that direct determination of target velocity is possible by measurement of the Doppler shift. By combining the Doppler velocity measurement capability with the inherent high angular resolution and range accuracy of lidar it is possible to construct Doppler images of targets for target motion assessment. A coherent lidar based on a Tm,Ho:YAG 2-micrometer wavelength laser was constructed and successfully field tested on atmospheric targets in 1990. This lidar incorporated an all solid state (laser diode pumped) master oscillator, in conjunction with a flash lamp pumped slave oscillator. Solid-state laser technology is rapidly advancing, and with the advent of high efficiency, high power, semiconductor laser diodes as pump sources, all-solid-state, coherent lidars are a real possibility in the near future. MSFC currently has a feasibility demonstration effort under way which will involve component testing, and preliminary design of an all-solid-state, coherent lidar for automatic rendezvous, and capture. This two year effort, funded by the Director's Discretionary Fund is due for completion in 1992.

  5. Rendezvous, Landing and Sample Return Mission to Jupiter Trojans by the Solar Power Sail

    NASA Astrophysics Data System (ADS)

    Yano, Hajime; Matsuura, Shuji; Mori, Osamu; Yonetoku, Daisuke; Nakamura, Ryosuke; Sekine, Yasuhito; Abe, Shinsuke

    JAXA/ISAS has been preparing for the Solar Power Sail mission, Japan’s first outer planet region exploration. Its precursor was successfully realized by IKAROS, the world's first deep space solar sail spacecraft, in 2010 between the Earth and Venus orbits. The Solar Power Sail is defined primarily as a technology demonstration mission; yet it will also present game-changing opportunities for both space astronomy and solar system exploration. The former will benefit the cruising operation, which will enable ”dust free” infrared astronomy beyond the cocoon of the zodiacal light to search for the first generation light of the Universe. Interplanetary-long baseline will allow gamma-ray burst observation to identify their source locations much more precise than ever. As for solar system exploration, the Solar Power Sail, which is not depended upon RTG technology, will offer the world's first possibility of rendezvous, landing and sample return from the outer planet region, i.e., in the Jupiter region and beyond. With this technology, we are aiming to visit Jupiter Trojan asteroids, one of the last uncharted frontiers of the Solar System. Jupiter Trojans may hold fundamental clues of the Solar System formation and revolution discussed by two competing hypotheses between the classic model and the planetary migration model. The former suggests that Trojan asteroids are mainly survivors of building blocks of the Jupiter system, while the latter claims that they must be intruders from outer regions after the planetary migration of gas planets settled. This paper outlines scientific objectives of Jupiter Trojan exploration, its mission design and major aspects of the spacecraft system, nature of candidate target asteroids, in-situ observation and lander instruments including optical camera, imaging spectrometer, high-resolution TOF mass spectrometer, and large-area dust counter, together with a strategy of the sample return option from the surface of a Trojan asteroid.

  6. Rendezvous with Toutatis from the Moon: The Chang'e-2 mission

    NASA Astrophysics Data System (ADS)

    Huang, J.; Tang, X.; Meng, L.

    2014-07-01

    Chang'e-2 probe was the second lunar probe of China, with the main objectives to demonstrate some key features of the new lunar soft landing technology, and its applications to future exploration missions. After completing the planned mission successfully, Chang'e-2 flew away from the Moon and entered into the interplanetary space. Later, at a distance of 7 million km from the Earth, Chang'e-2 encountered asteroid (4179) Toutatis with a very close fly-by distance and obtained colorful images with a 3-m resolution. Given some surplus velocity increment as well as the promotion of autonomous flight ability and improvement of control, propulsion, and thermal systems in the initial design, Chang'e-2 had the capabilities necessary for escaping from the Moon. By taking advantage of the unique features of the Lagrangian point, the first close fly-by of asteroid Toutatis was realized despite the tight constraints of propellant allocation, spacecraft-Earth communication, and coordination of execution sequences. Chang'e-2 realized the Toutatis flyby with a km-level distance at closest approach. In the absence of direct measurement method, based on the principle of relative navigation and through the use of the sequence of target images, we calculated the rendezvous parameters such as relative distance and image resolution. With the help of these parameters, some fine and new scientific discoveries about the asteroid were obtained by techniques of optical measurements and image processing. Starting with an innovative design, followed by high-fidelity testing and demonstration, elaborative implementation, and optimal usage of residual propellant, Chang'e-2 has for the first time successfully explored the Moon, L2 point and an asteroid, while achieving the purpose of 'faster, better, cheaper'. What Chang'e-2 has accomplished was far beyond our expectations. *J. Huang is the chief designer (PI) of Chang'e-2 probe, planned Chang'e-2's multi-objective and multitasking exploration mission.

  7. A Prediction Method of TV Camera Image for Space Manual-control Rendezvous and Docking

    NASA Astrophysics Data System (ADS)

    Zhen, Huang; Qing, Yang; Wenrui, Wu

    Space manual-control rendezvous and docking (RVD) is a key technology for accomplishing the RVD mission in manned space engineering, especially when automatic control system is out of work. The pilot on chase spacecraft manipulates the hand-stick by the image of target spacecraft captured by TV camera. From the TV image, the relative position and attitude of chase and target spacecrafts can be shown. Therefore, the size, the position, the brightness and the shadow of the target on TV camera are key to guarantee the success of manual-control RVD. A method of predicting the on-orbit TV camera image at different relative positions and light conditions during the process of RVD is discussed. Firstly, the basic principle of capturing the image of cross drone on target spacecraft by TV camera is analyzed theoretically, based which the strategy of manual-control RVD is discussed in detail. Secondly, the relationship between the displayed size or position and the real relative distance of chase and target spacecrafts is presented, the brightness and reflection by the target spacecraft at different light conditions are decribed, the shadow on cross drone caused by the chase or target spacecraft is analyzed. Thirdly, a prediction method of on-orbit TV camera images at certain orbit and light condition is provided, and the characteristics of TV camera image during the RVD is analyzed. Finally, the size, the position, the brightness and the shadow of target spacecraft on TV camera image at typical orbit is simulated. The result, by comparing the simulated images with the real images captured by the TV camera on Shenzhou manned spaceship , shows that the prediction method is reasonable

  8. A multiple-rendezvous, sample-return mission to two near-Earth asteroids

    NASA Astrophysics Data System (ADS)

    Duffard, R.; Kumar, K.; Pirrotta, S.; Salatti, M.; Kubínyi, M.; Derz, U.; Armytage, R. M. G.; Arloth, S.; Donati, L.; Duricic, A.; Flahaut, J.; Hempel, S.; Pollinger, A.; Poulsen, S.

    2011-07-01

    We propose a dual-rendezvous mission, targeting near-Earth asteroids, including sample-return. The mission, Asteroid Sampling Mission (ASM), consists of two parts: (i) flyby and remote sensing of a Q-type asteroid, and (ii) sampling of a V-type asteroid. The targeted undifferentiated Q-type are found mainly in the near-Earth space, and to this date have not been the target of a space mission. We have chosen, for our sampling target, an asteroid from the basaltic class (V-type), as asteroids in this class exhibit spectral signatures that resemble those of the well-studied Howardite-Eucrite-Diogenite (HED) meteorite suite. With this mission, we expect to answer specific questions about the links between differentiated meteorites and asteroids, as well as gain further insight into the broader issues of early Solar System (SS) evolution and the formation of terrestrial planets. To achieve the mission, we designed a spacecraft with a dry mass of less than 3 tonnes that uses electric propulsion with a solar-electric power supply of 15 kW at 1 Astronomical Unit (AU). The mission includes a series of remote sensing instruments, envisages landing of the whole spacecraft on the sampling target, and employs an innovative sampling mechanism. Launch is foreseen to occur in 2018, as the designed timetable, and the mission would last about 10 years, bringing back a 150 g subsurface sample within a small re-entry capsule. This paper is a work presented at the 2008 Summer School Alpbach,"Sample return from the Moon, asteroids and comets" organized by the Aeronautics and Space Agency of the Austrian Research Promotion Agency. It is co-sponsored by ESA and the national space authorities of its Member and Co-operating States, with the support of the International Space Science Institute and Austrospace.

  9. A new way in intelligent recognition improves control accuracy and efficiency for spacecrafts' rendezvous and docking

    NASA Astrophysics Data System (ADS)

    Wang, JiaQing; Lu, Yaodong; Wang, JiaFa

    2013-08-01

    Spacecrafts rendezvous and docking (RVD) by human or autonomous control is a complicated and difficult problem especially in the final approach stage. Present control methods have their key technology weakness. It is a necessary, important and difficult step for RVD through human's aiming chaser spacecraft at target spacecraft in a coaxial line by a three-dimension bulge cross target. At present, there is no technology to quantify the alignment in image recognition direction. We present a new practical autonomous method to improve the accuracy and efficiency of RVD control by adding image recognition algorithm instead of human aiming and control. Target spacecraft has a bulge cross target which is designed for chaser spacecraft's aiming accurately and have two center points, one is a plate surface center point(PSCP), another is a bulge cross center point(BCCP), while chaser spacecraft has a monitoring ruler cross center point(RCCP) of the video telescope optical system for aiming . If the three center points are coincident at the monitoring image, the two spacecrafts keep aligning which is suitable for closing to docking. Using the trace spacecraft's video telescope optical system to acquire the real-time monitoring image of the target spacecraft's bulge cross target. Appling image processing and intelligent recognition algorithm to get rid of interference source to compute the three center points' coordinate and exact digital offset of two spacecrafts' relative position and attitude real-timely, which is used to control the chaser spacecraft pneumatic driving system to change the spacecraft attitude in six direction: up, down, front, back, left, right, pitch, drift and roll precisely. This way is also practical and economical because it needs not adding any hardware, only adding the real-time image recognition software into spacecrafts' present video system. It is suitable for autonomous control and human control.

  10. 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.

  11. Fifth Report of the NASA Advisory Council Task Force on the Shuttle-Mir Rendezvous and Docking Missions

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The NASA Advisory Council Task Force on the Shuttle-Mir rendezvous and docking missions examine a number of specific issues related to the Shuttle-Mir program. Three teams composed of Task Force members and technical advisors were formed to address the follow issues: preliminary results from STS-71 and the status of preparations for STS-74; NASA's presence in Russia; and NASA's automated data processing and telecommunications (ADP/T) infrastructure in Russia. The three review team reports have been included in the fifth report of the Task Force.

  12. Mission analysis and guidance, navigation, and control design for rendezvous and docking phase of advanced reentry vehicle mission

    NASA Astrophysics Data System (ADS)

    Strippoli, L.; Colmenarejo, P.; Strauch, H.

    2013-12-01

    Advanced Reentry Vehicle (ARV) belongs to the family of vehicles designed to perform rendezvous and docking (RvD) with the International space station (ISS) [1]. Differently from its predecessor ATV (Automated Transfer Vehicle), the ARV will transport a reentry capsule, equipped with a heatshield and able to bring back cargo, experiments, or, as a possible future development, even crew, being this latter scenario very attracting in view of the Space Shuttle retirement. GMV, as subcontractor of EADS-Astrium Germany, is in charge of the RvD and departure mission analysis and GNC (Guidance, Navigation, and Control) design of ARV mission. This paper will present the main outcomes of the study.

  13. Infrared focal plane design for the Comet Rendezvous/Asteroid Flyby and Cassini Visible and Infrared Mapping Spectrometers

    NASA Technical Reports Server (NTRS)

    Staller, Craig; Niblack, Curtiss; Evans, Thomas; Blessinger, Michael; Westrick, Anthony

    1991-01-01

    A focal plane assembly combining hybrid electronic components with passive optical components within a single hermetically sealed package has been designed by Cincinnati Electronics to meet the performance requirements imposed by the Comet Rendezvous/Asteroid Flyby (CRAF) and Cassini Visible and Infrared Mapping Spectrometers (VIMSs). A single line array of 256 InSb photodiodes, accessed by two 1 x 128 multiplexers, provides continuous spectral coverage from 0.85 to 5.1 microns. Intrinsic field-of-view apertures and a unique order sorting filter require critical optical alignment within the hybrid. FPA performance requirements, design approach, and critical issues are discussed.

  14. NASA's Automated Rendezvous and Docking/Capture Sensor Development and Its Applicability to the GER

    NASA Technical Reports Server (NTRS)

    Hinkel, Heather; Cryan, Scott; DSouza, Christopher; Strube, Matthew

    2014-01-01

    This paper will address how a common Automated Rendezvous and Docking/Capture (AR&D/C) sensor suite can support Global Exploration Roadmap (GER) missions, and discuss how the model of common capability development to support multiple missions can enable system capability level partnerships and further GER objectives. NASA has initiated efforts to develop AR&D/C sensors, that are directly applicable to GER. NASA needs AR&D/C sensors for both the robotic and crewed segments of the Asteroid Redirect Mission (ARM). NASA recently conducted a commonality assessment of the concept of operations for the robotic Asteroid Redirect Vehicle (ARV) and the crewed mission segment using the Orion crew vehicle. The commonality assessment also considered several future exploration and science missions requiring an AR&D/C capability. Missions considered were asteroid sample return, satellite servicing, and planetary entry, descent, and landing. This assessment determined that a common sensor suite consisting of one or more visible wavelength cameras, a three-dimensional LIDAR along with long-wavelength infrared cameras for robustness and situational awareness could be used on each mission to eliminate the cost of multiple sensor developments and qualifications. By choosing sensor parameters at build time instead of at design time and, without having to requalify flight hardware, a specific mission can design overlapping bearing, range, relative attitude, and position measurement availability to suit their mission requirements with minimal nonrecurring engineering costs. The resulting common sensor specification provides the union of all performance requirements for each mission and represents an improvement over the current systems used for AR&D/C today. NASA's AR&D/C sensor development path could benefit the International Exploration Coordination Group (ISECG) and support the GER mission scenario by providing a common sensor suite upon which GER objectives could be achieved while minimizing development costs. The paper will describe the concepts of operations of these missions and how the common sensors are utilized by each mission. It will also detail the potential partnerships and contribution of the International community in the development of this common AR&D/C sensor suite.

  15. Magnetometer-Only Attitude and Rate Estimates for Spinning Spacecraft

    NASA Technical Reports Server (NTRS)

    Challa, M.; Natanson, G.; Ottenstein, N.

    2000-01-01

    A deterministic algorithm and a Kalman filter for gyroless spacecraft are used independently to estimate the three-axis attitude and rates of rapidly spinning spacecraft using only magnetometer data. In-flight data from the Wide-Field Infrared Explorer (WIRE) during its tumble, and the Fast Auroral Snapshot Explorer (FAST) during its nominal mission mode are used to show that the algorithms can successfully estimate the above in spite of the high rates. Results using simulated data are used to illustrate the importance of accurate and frequent data.

  16. An Investigation of Multipath Effects on the GPS System During Auto-Rendezvous and Capture

    NASA Technical Reports Server (NTRS)

    Richie, James E.; Forest, Francis W.

    1995-01-01

    The proposed use of a Cargo Transport Vehicle (CTV) to carry hardware to the Space Station Freedom (SSF) during the construction phase of the SSF project requires remote maneuvering of the CTV. The CTV is not a manned vehicle. Obtaining the relative positions of the CTV and SSF for remote auto-rendezvous and capture (AR&C) scenarios will rely heavily on the Global Positioning System (GPS). The GPS system is expected to guide the CTV up to a distance of 100 to 300 meters from the SSF. At some point within this range, an optical docking system will take over the remote guidance for capture. During any remote guidance by GPS it is possible that significant multipath signals may be caused by large objects in the vicinity of the module being remotely guided. This could alter the position obtained by the GPS system from the actual position. Due to the nature of the GPS signals, it has been estimated that if the difference in distance between the Line of Sight (LOS) path and the multipath is greater than 300 meters, the GPS system is capable of discriminating between the direct signal and the reflected (or multipath) signal. However, if the path difference is less than 300 meters, one must be concerned. This report details the work accomplished by the Electromagnetic Simulations Laboratory at Marquette University over the period December 1993 to May 1995. This work is an investigation of the strength and phase of a multipath signal arriving at the CTV relative to the direct or line of sight (LOS) signal. The signal originates at a GPS satellite in half geo-stationary orbit and takes two paths to the CTV: (1) the direct or LOS path from the GPS satellite to the CTV; and (2) a scattered path from the GPS satellite to the SSF module and then to the CTV. The scattering from a cylinder has been computed using the physical optics approximation for the current. No other approximations or assumptions have been made including no assumptions regarding the far field or Fresnel field approximations. The integrations required to obtain the scattered field have been computed numerically using an N dimensional Romberg integration. The total scattered electric field is then projected onto the RCP component in the direction of propagation only. The direct or line of sight signal is then used to compute the relative strength and phase of the scattered field. The trajectory of the CTV has been parameterized into 4,214 points that are calculated for each of the geometries investigated. The motion of the CTV between points is small enough for the magnitude data (dB down from direct signal) to appear very smooth; however, because of the distances and wavelengths involved, the phase of the scattered field relative to the direct signal varies very rapidly.

  17. Design and Performance Analysis of GPS Based Precise Relative Navigation for Rendezvous and Formation Flying Missions in Low Earth Orbit

    NASA Astrophysics Data System (ADS)

    Yamamoto, Toru

    Precise relative GPS navigation is essential technology for rendezvous and formation flying of spacecraft in Low Earth Orbit. Key design issues of precise relative GPS navigation software are studied and a novel formulation is proposed for the mission which requires high accuracy when the separation distance is up to several km. The navigation filter estimates float navigation solutions by extended Kalman filter with elaborate dynamics models, and resolves ambiguities of integer carrier phase biases to achieve high accuracy fix navigation solutions. A relative navigation software with the proposed formulation is implemented and evaluated in two different ways. One is a test using spacebourne GPS receivers and a GPS signal simulator to evaluate the performance and sensitivity of the software against variation of parameters. The other is a test using actual telemetry data from Gravity Recovery and Climate Experiment (GRACE) to demonstrate the software performance. The design, implementation, and results of the evaluation are presented and discussed on this paper.

  18. Coordinated Radio, Electron, and Waves Experiment (CREWE) for the NASA Comet Rendezvous and Asteroid Flyby (CRAF) instrument

    NASA Technical Reports Server (NTRS)

    Scudder, Jack D.

    1992-01-01

    The Coordinated Radio, Electron, and Waves Experiment (CREWE) was designed to determine density, bulk velocity and temperature of the electrons for the NASA Comet Rendezvous and Asteroid Flyby Spacecraft, to define the MHD-SW IMF flow configuration; to clarify the role of impact ionization processes, to comment on the importance of anomalous ionization phenomena (via wave particle processes), to quantify the importance of wave turbulence in the cometary interaction, to establish the importance of photoionization via the presence of characteristic lines in a structured energy spectrum, to infer the presence and grain size of significant ambient dust column density, to search for the theoretically suggested 'impenetrable' contact surface, and to quantify the flow of heat (in the likelihood that no surface exists) that will penetrate very deep into the atmosphere supplying a good deal of heat via impact and charge exchange ionization. This final report provides an instrument description, instrument test plans, list of deliverables/schedule, flight and support equipment and software schedule, CREWE accommodation issues, resource requirements, status of major contracts, an explanation of the non-NASA funded efforts, status of EIP and IM plan, descope options, and Brinton questions.

  19. 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.

  20. Technology Development of Automated Rendezvous and Docking/Capture Sensors and Docking Mechanism for the Asteroid Redirect Crewed Mission

    NASA Technical Reports Server (NTRS)

    Hinkel, Heather; Cryan, Scott; Zipay, John; Strube, Matthew

    2015-01-01

    This paper will describe the technology development efforts NASA has underway for Automated Rendezvous and Docking/Capture (AR&D/C) sensors and a docking mechanism and the challenges involved. The paper will additionally address how these technologies will be extended to other missions requiring AR&D/C whether robotic or manned. NASA needs AR&D/C sensors for both the robotic and crewed segments of the Asteroid Redirect Mission (ARM). NASA recently conducted a commonality assessment of the concept of operations for the robotic Asteroid Redirect Vehicle (ARV) and the crewed mission segment using the Orion crew vehicle. The commonality assessment also considered several future exploration and science missions requiring an AR&D/C capability. Missions considered were asteroid sample return, satellite servicing, and planetary entry, descent, and landing. This assessment determined that a common sensor suite consisting of one or more visible wavelength cameras, a threedimensional LIDAR along with long-wavelength infrared cameras for robustness and situational awareness could be used on each mission to eliminate the cost of multiple sensor developments and qualifications. By choosing sensor parameters at build time instead of at design time and, without having to requalify flight hardware, a specific mission can design overlapping bearing, range, relative attitude, and position measurement availability to suit their mission requirements with minimal nonrecurring engineering costs. The resulting common sensor specification provides the union of all performance requirements for each mission and represents an improvement over the current systems used for AR&D/C today. These sensor specifications are tightly coupled to the docking system capabilities and requirements for final docking conditions. The paper will describe NASA's efforts to develop a standard docking system for use across NASA human spaceflight missions to multiple destinations. It will describe the current design status and the considerations and technologies involved in developing this docking mechanism.

  1. Technology Development of Automated Rendezvous and Docking/Capture Sensors and Docking Mechanism for the Asteroid Redirect Crewed Mission

    NASA Technical Reports Server (NTRS)

    Hinkel, Heather; Strube, Matthew; Zipay, John J.; Cryan, Scott

    2015-01-01

    This paper will describe the technology development efforts NASA has underway for Automated Rendezvous and Docking/Capture (AR and D/C) sensors and a docking mechanism and the challenges involved. The paper will additionally address how these technologies will be extended to other missions requiring AR and D/C whether robotic or manned. NASA needs AR&D/C sensors for both the robotic and crewed segments of the Asteroid Redirect Mission (ARM). NASA recently conducted a commonality assessment of the concept of operations for the robotic Asteroid Redirect Vehicle (ARV) and the crewed mission segment using the Orion crew vehicle. The commonality assessment also considered several future exploration and science missions requiring an AR and D/C capability. Missions considered were asteroid sample return, satellite servicing, and planetary entry, descent, and landing. This assessment determined that a common sensor suite consisting of one or more visible wavelength cameras, a threedimensional LIDAR along with long-wavelength infrared cameras for robustness and situational awareness could be used on each mission to eliminate the cost of multiple sensor developments and qualifications. By choosing sensor parameters at build time instead of at design time and, without having to requalify flight hardware, a specific mission can design overlapping bearing, range, relative attitude, and position measurement availability to suit their mission requirements with minimal nonrecurring engineering costs. The resulting common sensor specification provides the union of all performance requirements for each mission and represents an improvement over the current systems used for AR and D/C today. These sensor specifications are tightly coupled to the docking system capabilities and requirements for final docking conditions. The paper will describe NASA's efforts to develop a standard docking system for use across NASA human spaceflight missions to multiple destinations. It will describe the current design status and the considerations and technologies involved in developing this docking mechanism.

  2. Technology Development of Automated Rendezvous and Docking/Capture Sensors and Docking Mechanism for the Asteroid Redirect Crewed Mission

    NASA Technical Reports Server (NTRS)

    Hinkel, Heather; Strube, Matthew; Zipay, John J.; Cryan, Scott

    2016-01-01

    This paper will describe the technology development efforts NASA has underway for Automated Rendezvous and Docking/Capture (AR&D/C) sensors and a docking mechanism and the challenges involved. The paper will additionally address how these technologies will be extended to other missions requiring AR&D/C whether robotic or manned. NASA needs AR&D/C sensors for both the robotic and crewed segments of the Asteroid Redirect Mission (ARM). NASA recently conducted a commonality assessment of the concept of operations for the robotic Asteroid Redirect Vehicle (ARV) and the crewed mission segment using the Orion spacecraft. The commonality assessment also considered several future exploration and science missions requiring an AR&D/C capability. Missions considered were asteroid sample return, satellite servicing, and planetary entry, descent, and landing. This assessment determined that a common sensor suite consisting of one or more visible wavelength cameras, a three-dimensional LIDAR along with long-wavelength infrared cameras for robustness and situational awareness could be used on each mission to eliminate the cost of multiple sensor developments and qualifications. By choosing sensor parameters at build-time instead of at design-time and, without having to requalify flight hardware, a specific mission can design overlapping bearing, range, relative attitude, and position measurement availability to suit their mission requirements with minimal non-recurring engineering costs. The resulting common sensor specification provides the union of all performance requirements for each mission and represents an improvement over the current systems used for AR&D/C today. These sensor specifications are tightly coupled to the docking system capabilities and requirements for final docking conditions. The paper will describe NASA's efforts to develop a standard docking system for use across NASA human spaceflight missions to multiple destinations. It will describe the current design status and the considerations and technologies involved in developing this docking mechanism.

  3. Analysis of control accuracy in the final phase of the rendezvous between the Automated Transfer Vehicle and the Space Station Freedom

    NASA Astrophysics Data System (ADS)

    Clar, Philippe G.; Theillier, Francis; Triou, Henri

    The Automated Transfer Vehicle (ATV) is an expendable unmanned vehicle launched by Ariane 5. The ATV's reference mission is to support the Space Station Freedom (SSF). The ascent part of the ATV's mission is to reach a given berthing point next to the SSF, within required accuracies. The vehicle must be able to hold this position in order to be grappled by the SSF's robotic arm. With the SSF's monitoring and authorizations, the ATV is designed to be able to achieve automatic rendezvous operations within the SSF's manned environment. During the final approach, the ATV's motion is a forced translation parallel to the SSF velocity axis. The control accuracy, estimated around this reference trajectory, is a key parameter for respect of safety requirements, and the purpose for this paper. After a brief description of the ATV's reference mission, we will focus on the last 100 meters of the rendezvous between the ATV and the SSF. We will begin by describing the modeling principles and the simplifying assumptions used to obtain a dynamic model for the relative distance between the ATV and SSF berthing points. The principles of the ATV rendezvous optical sensor and thruster architecture will also be discussed. The design of a control aimed at maintaining the reference trajectory will next be considered along with the effects of measurement and modeling disturbances, noise as well as bias, on the control accuracy. The results demonstrate that the accuracy achieved around the reference trajectory remains compliant with the berthing requirements and would even allow direct docking if needed.

  4. 'Run-and-tumble' or 'look-and-run'? A mechanical model to explore the behavior of a migrating amoeboid cell.

    PubMed

    Allena, Rachele; Aubry, Denis

    2012-08-01

    Single cell migration constitutes a fundamental phenomenon involved in many biological events. Amoeboid cells are single cell organisms that migrate in a cyclic manner like worms. In this paper, we propose a 3D finite element model of an amoeboid cell migrating over a 2D surface. In particular, we focus on the mechanical aspect of the problem. The cell is able to generate cyclic active deformations, such as protrusion and contraction, in any direction. The progression of the cell is governed by a tight synchronization between the adhesion forces, which are alternatively applied at the front and at the rear edges of the cell, and the protrusion-contraction phases of the cell body. Finally, two important aspects have been taken into account: (1) the external stimuli in response to which the cell migrates (e.g. need to feed, morphogenetic events, normal or abnormal environment cues), (2) the heterogeneity of the 2D substrate (e.g. obstacles, rugosity, slippy regions) for which two distinct approaches have been evaluated: the 'run-and-tumble' strategy and the 'look-and-run' strategy. Overall, the results show a good agreement with respect to the experimental observations and the data from the literature (e.g. velocity and strains). Therefore, the present model helps, on one hand, to better understand the intimate relationship between the deformation modes of a cell and the adhesion strength that is required by the cell to crawl over a substrate, and, on the other hand, to put in evidence the crucial role played by mechanics during the migration process. PMID:22726805

  5. Spontaneous Rupture of Superficial Femoral Artery Repaired with Endovascular Stent-Grafting with use of Rendez-Vous Technique, Followed by Delayed Infection

    SciTech Connect

    Fanelli, Fabrizio Cannavale, Alessandro; Gazzetti, Marianna; Fantozzi, Cristiano; Taurino, Maurizio; Speziale, Francesco

    2013-02-15

    This is the case of a 72-year-old man with lower limb ischemia due to spontaneous rupture of nonaneurysmal superficial femoral artery that developed into thigh hematoma. After failure of a Fogarty revascularization, an emergency endovascular procedure was performed to restore the arterial continuity. A rendezvous procedure was performed with a double femoral and popliteal approach and two covered stent-grafts were deployed. Patient's clinical conditions immediately improved, but 4 months later the stent-grafts were surgically removed for infection and exteriorization. A femoropopliteal bypass was performed. After 1 year follow-up, the patient is in good clinical condition.

  6. Trojan Tour and Rendezvous (TTR): A New Frontiers Mission to Conduct the First Detailed Reconnaissance of the Jupiter Trojan Asteroids

    NASA Astrophysics Data System (ADS)

    Bell, James F.; Olkin, Cathy; Castillo-Rogez, Julie

    2015-11-01

    Among the most potentially diagnostic but least explored populations of small bodies are the Jupiter Trojan asteroids, which orbit at ~5 AU in the L4 and L5 Lagrange points of Jupiter. The Trojans provide a unique perspective on solar system history, because their locations and physical, compositional, and mineralogic properties preserve evidence for important gravitational interactions among the giant planets. The locations and orbital properties of more than 6200 Jupiter Trojans are now known, but that is likely only a small fraction of a population of up to ~1e6 Trojans >1 km in size. The Trojans are hypothesized to be either former KBOs scattered into the inner solar system by early giant planet migration and then trapped in L4 and L5, or bodies formed near 5 AU in a more quiescent early solar system.Important Planetary Decadal Survey questions that can be addressed by studying the Trojans include: (a) How did the giant planets and their satellite systems accrete, and is there evidence that they migrated to new orbital positions? (b) What is the relationship between large and small KBOs? Is the small population derived by impact disruption of the large one? (c) What kinds of surface evolution, radiation chemistry, and surface-atmosphere interactions occur on distant icy primitive bodies? And (d) What are the sources of asteroid groups (Trojans and Centaurs) that remain to be explored by spacecraft?Here we describe the Trojan Tour and Rendezvous (TTR) New Frontiers mission concept, which is designed to answer these Decadal questions and to test hypotheses for early giant planet migration and solar system evolution. Via close flybys of many of these objects, and orbital characterization of at least one large Trojan, TTR will enable the initial up-close exploration of this population. Our primary mission goals are to characterize the overall surface geology, geochemistry and mineralogy of these worlds; to characterize their internal structure and dynamical properties; to investigate the nature, sources and history of activity on these bodies; and to explore the diversity of the broader Trojan asteroid population.

  7. Light scattering observations and simulations, as hints about the media encountered by future rendezvous missions to comets and asteroids

    NASA Astrophysics Data System (ADS)

    Levasseur-Regourd, Anny-Chantal

    The success of future rendezvous mission to comets (i.e. Rosetta, which will explore the innermost coma of 67P/Churyumov-Gerasimenko, before deploying a lander on its nucleus in 2014) and asteroids (e.g. Marco-Polo candidate mission for ESA Cosmic Vision) require some understanding of the physical properties of the dust particles encountered in the coma (if any) and on the solid surface. Analysis of observations of the linear polarization of solar light scattered by such media may provide clues to their properties [1]. The polarization is actually a dimension-less ratio, which only varies with the geometry of the observations (i.e. phase angle), with the wavelength, and with the properties of the scattering medium. Comparisons between the shapes of the polarimetric phase curves of asteroids [2] and comets [3] provide a classification with respect to the dust properties. As far as asteroids are concerned, this classification is reminiscent of the taxonomic classes, and more information is expected from detailed studies of the wavelength dependence. As far as comets are concerned, an extensive programme of numerical and laboratory simulations with various irregular compact grains and aggregates has been developed in the past years [4,5]. Comparisons of the results with observations (tentatively on a large range of phase angles and wavelengths) have allowed us to suggest that cometary dust particles are built of both very fluffy aggregates and of more compact grains, with significant proportions of both rather transparent silicates and absorbing materials [6]. These estimations are confirmed by the analysis of Stardust samples, with, e.g. evidence for dense grains and aggregates with low bulk density within the coma of comet Wild 2 [7]. It may thus be concluded that the analysis of remote light scattering observations allows us to infer some properties of the scattering media, to point out some similarities and discrepancies between small solar system bodies, and to contribute to the success of future space missions. [1] Levasseur-Regourd and Hadamcik, J. Quant. Spectros. Radiat. Transfer 79, 903-910, 2003. [2] Pentill¨ et al., Astron. Astrophys. 432, 1081-1090, 2005. [3] Levasseur-Regourd a et al., Astron. Astrophys. 313, 327-333, 1996. [4] Lasue and Levasseur-Regourd, J. Quant. Spectros. Radiat. Transfer 100, 220-236, 2006. [5] Hadamcik et al., Icarus 190, 660-671, 2007. [6] Levasseur-Regourd et al., Planet. Space Sci. 55, 1010-1020, 2007. [7] H¨rz et al., Science o 314, 1716-1719 (2006).

  8. Investigation of the Spinning and Tumbling Characteristics of a 1/25-Scale Model of the Lockheed XFV-1 Airplane in the Langley 20-Foot Free-Spinning Tunnel

    NASA Technical Reports Server (NTRS)

    Lee, Henry A.

    1953-01-01

    An investigation has been conducted in the Langley 20-foot free-spinning tunnel on a l/23-scale model of the Lockheed XFV-1 airplane to determine the effects of control setting and movement upon the erect-spin and recovery characteristics for a range of airplane loading conditions. A windmilling propeller was simulated on the model for some of the tests. The investigation included determination of the size of tail parachute required for emergency recovery from demonstration spins. The tumbling tendencies of the model were also investigated. The results indicated that any erect or inverted spin obtained on the airplane will be satisfactorily terminated if recovery is attempted by full rudder reversal accompanied by simultaneous lateral and longitudinal movement of the stick to neutral, The model test results showed that an 11.5-foot flat-type tail parachute (drag coefficient approximately 0.73) with a 27.5-foot towline will be effective as an emergency spin-recovery device during demonstration spins of the airplane. The model results also indicate that the airplane will not tumble for any.loading condition indicated possible.

  9. Tumbling sandpiles in a fluid

    NASA Astrophysics Data System (ADS)

    Radjai, Farhang; Topin, Vincent; Perales, Frédéric; Monerie, Yann

    2013-06-01

    By means of contact dynamics simulations interfaced with computational fluid dynamics, we analyze the effect of a suspending fluid on the dynamics of collapse and spread of a granular column. We find that the runout distance increases as a power law with the aspect ratio of the column and, for a given aspect ratio, it may be the same in the grain-inertial and fluid-inertial regimes but with considerably longer duration in the latter case. We show that, in both viscous and fluid-inertial regimes, this behavior results from compensation between two effects of the fluid: 1) reduction of the kinetic energy during collapse and 2) enhancement of the flow by lubrication during spread.

  10. DARe: Dark Asteroid Rendezvous

    NASA Technical Reports Server (NTRS)

    Noll, K. S.; McFadden, L. A.; Rhoden, A. R.; Lim, L. F.; Boynton, W. V.; Carter, L. M.; Collins, G.; Englander, J. A.; Goossens, S. A.; Grundy, W. M.; Li, J.-Y.; Mottola, S.; Oberst, J.; Orosei, R.; Parsons, A. M.; Preusker, F.; Reuter, D. C.; Simon, A. A.; Thomas, C. A.; Walsh, K.; Zolensky, M. E.

    2015-01-01

    Small bodies record the chemical, physical, and dynamical processes that gave birth to and shaped the solar system. The great variety of small bodies reflects the diversity of both their genesis and their histories. The DARe mission conducts a critical test of how small body populations reflect a history of planetary migration and planetesimal scattering. This understanding is crucial for planning future NASA missions and placing current and past missions into context.

  11. Noncooperative rendezvous radar system

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A fire control radar system was developed, assembled, and modified. The baseline system and modified angle tracking system are described along with the performance characteristics of the baseline and modified systems. Proposed changes to provide additional techniques for radar evaluation are presented along with flight test data.

  12. Celebrating Soft Matter's 10th Anniversary: chain configuration and rate-dependent mechanical properties in transient networks.

    PubMed

    Sing, Michelle K; Wang, Zhen-Gang; McKinley, Gareth H; Olsen, Bradley D

    2015-03-21

    Numerical solution of a coupled set of Smoluchowski convection-diffusion equations of associating polymers modelled as finitely extensible dumbbells enables computation of time-dependent end-to-end distributions for bridged, dangling, and looped chains in three dimensions as a function of associating end-group kinetics. Non-monotonic flow curves which can lead to flow instabilities during shear flow result at low equilibrium constant and high association rate from two complementary phenomena: a decrease in the fraction of elastically active chains with increasing shear rate and non-monotonic extension in the population of elastically active chains. Chain tumbling leads to reformation of bridges, resulting in an increased fraction of bridged chains at high Deborah number and significant reduction in the average bridge chain extension. In the start-up of steady shear, force-activated chain dissociation and chain tumbling cause both stress overshoot and stress ringing behaviour prior to reaching steady state stress values. During stress relaxation following steady shear, chain kinetics and extension mediate both the number of relaxations and the length of time required for system relaxation. While at low association rate relaxation is limited by the relaxation of dangling chains and the rate of dangling chain formation, at high association rate coupling of dangling and bridged chains leads to simultaneous relaxation of all chains due to a dynamic equilibrium between dangling and bridged states. PMID:25607419

  13. Modification of Platelet Margination Rate via Reduction of Viscosity Ratio

    NASA Astrophysics Data System (ADS)

    Reasor, Daniel; Mehrabadi, Marmar; Ku, David; Aidun, Cyrus

    2011-11-01

    Experimental investigations of platelet margination have primarily been limited to effects of hematocrit (Ht.) and shear rate. The suspending fluids used commonly have viscosities greater than plasma which can modify the transition in dynamical regimes from tumbling to tank-treading for isolated RBCs. This work focuses on the effects of ?, the ratio of internal to suspending fluid viscosity of RBCs, on the rate of platelet margination in a rigid 41.3 ?m diameter vessel. Simulations are performed with a lattice-Boltzmann fluid solver using the standard bounce-back boundary condition coupled with a coarse-grained spectrin-link RBC membrane model and a Newtonian dynamics solver for rigid platelets. Our results are consistent with observations that an increase in Ht. increases the rate of platelet margination for Ht.=20-40%, but we focus on the modification of ? at Ht.=20%. Our results show that rigid RBCs inhibit margination, but modifying ? with deformable RBCs show significant increases in margination rate. Our observations demonstrate an increase in platelet wall-normal velocity fluctuations, enhanced margination rate, and an increase in the wall-normal diffusivity as ? is reduced from the physiological value of five. NSF TeraGrid Grant: TG-CTS100012.

  14. Rate & Detection Rate by Age

    Cancer.gov

    Skip to Main Content Home   |   Data   |   Statistics   |   Tools   |   Collaborations   |   Work with Us   |   Publications   |   About   |   Links Cancer Rate (per 1,000 examinations) and Cancer Detection Rate (per 1,000 examinations) for 3,884,059

  15. Rate & Detection Rate by Age

    Cancer.gov

    Skip to Main Content Home   |   Data   |   Statistics   |   Tools   |   Collaborations   |   Work with Us   |   Publications   |   About   |   Links Cancer Rate (per 1,000 examinations) and Cancer Detection Rate (per 1,000 examinations) for 1,838,372

  16. The NEAR Rendezvous Burn Anomaly

    E-print Network

    Rhoads, James

    . Femiano NASA Goddard Space Flight Center H. Richard Freeman NASA Goddard Space Flight Center NEARAnomaly NASA Goddard Space Flight Center James G. Palmer JHU/Applied Physics Laboratory /s/ /s/ /s/ /s/ /s/ /s

  17. Tumbling: From Rally Cars to Toast

    NASA Astrophysics Data System (ADS)

    Belloni, Mario; Christian, Wolfgang

    2012-10-01

    The article by Rod Cross describing the translational and rotational motion of the "Launch of a Vehicle from a Ramp" motivated us to create two computer models showing this type of dynamical behavior.

  18. Are the Walls of Injustice Tumbling Down?

    ERIC Educational Resources Information Center

    Peterson, Rochelle R.; Davila, Erica R.

    2011-01-01

    The discussion of multicultural education in teacher preparation dates back several decades. "The historical roots of multicultural education lie in the civil rights movements of various historically oppressed groups" (Gorski, 1999, p.1). As communities of color resisted institutional racism, schools became one of the sites of struggle. Thus, the…

  19. Tumbling: From Rally Cars to Toast

    ERIC Educational Resources Information Center

    Belloni, Mario; Christian, Wolfgang

    2012-01-01

    The article by Rod Cross describing the translational and rotational motion of the "Launch of a Vehicle from a Ramp" motivated us to create two computer models showing this type of dynamical behavior.

  20. Coal - prices tumble as the glut continues

    SciTech Connect

    Lee, H.M.

    1987-03-01

    The oil price collapse was the major event affecting coal markets around the world in 1986. The 8% expansion in international coal trade in 1985 was halted, and prices fell considerably. World coking coal trade declined and import and export prices fell due to a decrease in steel production and the use of oil, rather than pulverized coal, in blast furnaces. However steam coal trade increased by about 5 million mt because of various institutional constraints to utilities switching from coal burning to oil burning. The article covers coal trade and production in the following countries: Australia; Canada; China; Colombia; Western Europe; Japan; Poland; South Africa; and the USSR.

  1. Death Rates

    Cancer.gov

    Close Window State Cancer Profiles Quick Reference Guides ? Quick Reference Guides Index Death Rates Send to Printer Text description of this image. Site Home Policies Accessibility Viewing Files FOIA Contact Us U.S. Department of Health and Human Services

  2. Incidence Rates

    Cancer.gov

    Close Window State Cancer Profiles Quick Reference Guides ? Quick Reference Guides Index Incidence Rates Send to Printer Text description of this image. Site Home Policies Accessibility Viewing Files FOIA Contact Us U.S. Department of Health and Human

  3. A Proposed Strategy for the U.S. to Develop and Maintain a Mainstream Capability Suite ("Warehouse") for Automated/Autonomous Rendezvous and Docking in Low Earth Orbit and Beyond

    NASA Technical Reports Server (NTRS)

    Krishnakumar, Kalmanje S.; Stillwater, Ryan A.; Babula, Maria; Moreau, Michael C.; Riedel, J. Ed; Mrozinski, Richard B.; Bradley, Arthur; Bryan, Thomas C.

    2012-01-01

    The ability of space assets to rendezvous and dock/capture/berth is a fundamental enabler for numerous classes of NASA fs missions, and is therefore an essential capability for the future of NASA. Mission classes include: ISS crew rotation, crewed exploration beyond low-Earth-orbit (LEO), on-orbit assembly, ISS cargo supply, crewed satellite servicing, robotic satellite servicing / debris mitigation, robotic sample return, and robotic small body (e.g. near-Earth object, NEO) proximity operations. For a variety of reasons to be described, NASA programs requiring Automated/Autonomous Rendezvous and Docking/Capture/Berthing (AR&D) capabilities are currently spending an order-of-magnitude more than necessary and taking twice as long as necessary to achieve their AR&D capability, "reinventing the wheel" for each program, and have fallen behind all of our foreign counterparts in AR&D technology (especially autonomy) in the process. To ensure future missions' reliability and crew safety (when applicable), to achieve the noted cost and schedule savings by eliminate costs of continually "reinventing the wheel ", the NASA AR&D Community of Practice (CoP) recommends NASA develop an AR&D Warehouse, detailed herein, which does not exist today. The term "warehouse" is used herein to refer to a toolbox or capability suite that has pre-integrated selectable supply-chain hardware and reusable software components that are considered ready-to-fly, low-risk, reliable, versatile, scalable, cost-effective, architecture and destination independent, that can be confidently utilized operationally on human spaceflight and robotic vehicles over a variety of mission classes and design reference missions, especially beyond LEO. The CoP also believes that it is imperative that NASA coordinate and integrate all current and proposed technology development activities into a cohesive cross-Agency strategy to produce and utilize this AR&D warehouse. An initial estimate indicates that if NASA strategically coordinates the development of a robust AR&D capability across the Agency, the cost of implementing AR&D on a spacecraft could be reduced from roughly $70M per mission to as low as $7M per mission, and the associated development time could be reduced from 4 years to 2 years, after the warehouse is completely developed. Table 1 shows the clear long-term benefits to the Agency in term of costs and schedules for various missions. (The methods used to arrive at the Table 1 numbers is presented in Appendices A and B.)

  4. The First Joint Report of the General Thomas P. Stafford Task Force and the Academician Vladimir F. Utkin Advisory Expert Council on the Shuttle-Mir Rendezvous and Docking Missions

    NASA Technical Reports Server (NTRS)

    1996-01-01

    In October 1992, the National Aeronautics and Space Administration (NASA) and the Russian Space Agency (RSA) formally agreed to conduct a fundamentally new program of human cooperation in space. The 'Shuttle-Mir Program' encompassed combined astronaut-cosmonaut activities on the Shuttle, Soyuz Test Module(TM), and Mir station spacecraft. At that time, NASA and RSA limited the project to: the STS-60 mission carrying the first Russian cosmonaut to fly on the U.S. Space Shuttle; the launch of the first U.S. astronaut on the Soyuz vehicle for a multi-month mission as a member of a Mir crew; and the change-out of the U.S.-Russian Mir crews with a Russian crew during a Shuttle rendezvous and docking mission with the Mir Station. The objectives of the Phase 1 Program are to provide the basis for the resolution of engineering and technical problems related to the implementation of the ISS and future U.S.-Russian cooperation in space. This, combined with test data generated during the course of the Shuttle flights to the Mir station and extended joint activities between U.S. astronauts and Russian cosmonauts aboard Mir, is expected to reduce the technical risks associated with the construction and operation of the ISS. Phase 1 will further enhance the ISS by combining space operations and joint space technology demonstrations. Phase 1 also provides early opportunities for extended U.S. scientific and research activities, prior to utilization of the ISS.

  5. Coding gains and error rates from the Big Viterbi Decoder

    NASA Technical Reports Server (NTRS)

    Onyszchuk, I. M.

    1991-01-01

    A prototype hardware Big Viterbi Decoder (BVD) was completed for an experiment with the Galileo Spacecraft. Searches for new convolutional codes, studies of Viterbi decoder hardware designs and architectures, mathematical formulations, and decompositions of the deBruijn graph into identical and hierarchical subgraphs, and very large scale integration (VLSI) chip design are just a few examples of tasks completed for this project. The BVD bit error rates (BER), measured from hardware and software simulations, are plotted as a function of bit signal to noise ratio E sub b/N sub 0 on the additive white Gaussian noise channel. Using the constraint length 15, rate 1/4, experimental convolutional code for the Galileo mission, the BVD gains 1.5 dB over the NASA standard (7,1/2) Maximum Likelihood Convolution Decoder (MCD) at a BER of 0.005. At this BER, the same gain results when the (255,233) NASA standard Reed-Solomon decoder is used, which yields a word error rate of 2.1 x 10(exp -8) and a BER of 1.4 x 10(exp -9). The (15, 1/6) code to be used by the Cometary Rendezvous Asteroid Flyby (CRAF)/Cassini Missions yields 1.7 dB of coding gain. These gains are measured with respect to symbols input to the BVD and increase with decreasing BER. Also, 8-bit input symbol quantization makes the BVD resistant to demodulated signal-level variations which may cause higher bandwidth than the NASA (7,1/2) code, these gains are offset by about 0.1 dB of expected additional receiver losses. Coding gains of several decibels are possible by compressing all spacecraft data.

  6. Method and associated apparatus for capturing, servicing, and de-orbiting earth satellites using robotics

    NASA Technical Reports Server (NTRS)

    Cepollina, Frank J. (Inventor); Burns, Richard D. (Inventor); Holz, Jill M. (Inventor); Corbo, James E. (Inventor); Jedhrich, Nicholas M. (Inventor)

    2009-01-01

    This invention is a method and supporting apparatus for autonomously capturing, servicing and de-orbiting a free-flying spacecraft, such as a satellite, using robotics. The capture of the spacecraft includes the steps of optically seeking and ranging the satellite using LIDAR, and matching tumble rates, rendezvousing and berthing with the satellite. Servicing of the spacecraft may be done using supervised autonomy, which is allowing a robot to execute a sequence of instructions without intervention from a remote human-occupied location. These instructions may be packaged at the remote station in a script and uplinked to the robot for execution upon remote command giving authority to proceed. Alternately, the instructions may be generated by Artificial Intelligence (AI) logic onboard the robot. In either case, the remote operator maintains the ability to abort an instruction or script at any time as well as the ability to intervene using manual override to teleoperate the robot.

  7. PARTICLE FILTERING RANGE DATA FOR POSE ESTIMATION UNDER TORQUE-FREE MOTION

    E-print Network

    an interest in eventual sample return missions from Mars or other extra- terrestrial sites of interest,rock}@stanford.edu ABSTRACT Autonomous rendezvous and capture is a current research interest with varied mission applications with an uncooperative tumbling target in orbit. One key to this process is the ability to estimate the relative pose

  8. Correlating field and laboratory rates of particle abrasion, Rio Medio, Sangre de Cristo Mountains, New Mexico

    NASA Astrophysics Data System (ADS)

    Polito, P. J.; Sklar, L. S.

    2006-12-01

    River bed sediments commonly fine downstream due to a combination of particle abrasion, selective transport of finer grains, and fining of the local sediment supply from hillslopes and tributaries. Particle abrasion rates can be directly measured in the laboratory using tumbling barrels and annular flumes, however, scaling experimental particle abrasion rates to the field has proven difficult due to the confounding effects of selective transport and local supply variations. Here we attempt to correlate laboratory and field rates of particle abrasion in a field setting where these confounding effects can be controlled. The Rio Medio, which flows westward from the crest of the Sangre de Cristo Mountains in north central New Mexico, is one of several streams studied by John P. Miller in the early 1960's. Several kilometers downstream of its headwaters, the river crosses the Picuris-Pecos fault. Upstream of the fault the river receives quartzite, sandstone and shale clasts from the Ortega Formation, while downstream sediments are supplied by the Embudo Granite. Because the upstream lithologies are not resupplied downstream of the fault, any observed fining of these clasts should be due only to abrasion and selective transport. We hypothesize that we can account for the effects of selective transport by comparing relative fining rates for the different upstream lithologies from both the field and a laboratory tumbler. By correlating laboratory abrasion rates with rock strength, we can predict the relative fining rates due solely to abrasion expected in the field; differences between the predicted and observed fining rates could then be attributed to selective transport. We used point counts to measure bed surface sediment grain size distributions at 15 locations along a 25 kilometer reach of the Rio Medio, beginning just downstream of the fault and ending upstream of a developed area with disturbed channel conditions. We recorded intermediate particle diameter as well as lithologic composition for 100 clasts at each location. To better characterize the size distribution of poorly represented lithologies we also measured every grain we could find of these minority lithologies within a one square meter area on adjacent bar top surfaces. At each sampling site we also measured channel gradient, and bank-full width and depth. We collected gravel samples for laboratory tumbling experiments and larger bedrock blocks from which we extracted cores for the Brazilian tensile splitting strength test. Preliminary results show very rapid fining of the weak sedimentary rocks downstream of the fault, much less rapid fining of the quartzite and a net downstream coarsening of the granitic sediments, which dominate the bed in the downstream end of the study reach. This enigmatic downstream coarsening may be a legacy of Pliestocene glaciation, which is evident in the landscape upstream of the fault. Outburst floods or debris flows from upstream moraines may have delivered large quantities of coarse sediments to downstream reaches, which are now relatively immobile. Despite these complications, the Rio Medio site may yet provide sufficient information to test our proposed method for scaling laboratory particle abrasion rates to the field.

  9. The gas production rate of periodic comet d'Arrest

    NASA Technical Reports Server (NTRS)

    Festou, Michel C.; Feldman, Paul D.; Ahearn, Michael F.

    1992-01-01

    Comet P/d'Arrest is a potential target for a rendezvous mission to a short period comet. Its light curve is rather peculiar, the comet being active only after perihelion passage. One apparition out of two is easy to observe from the ground. The 1995 apparition of the comet will offer a unique opportunity to characterize the outgassing properties of its nucleus.

  10. The Near-Earth Asteroid Rendezvous (NEAR) Mission, the Mars Surveyor 2001 (MS01) Mission, and the Planetary Instrument Definition and Development Program (PIDDP)

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The NEAR Mission was launched on February 17, 1996 for a three year cruise to the asteroid 433 Eros. During October, November, and December 1998 cruise measurements with the gamma-ray spectrometer were made at three different escape-window-width settings. These were done in order to understand how the count rate and peak width change as the window width settings change. Analysis of these spectra was completed using the latest version of the spectral analysis program, RobWin. Results as a function of energy were combined with the results from the Schlumberger-Doll Research experiments (described below). Laboratory measurements were needed to confirm efficiency calculations above 6 MeV and to understand the relationship between the full energy peak areas and the areas of the first and second escape peaks as a function of the escape peak widths. A week of measurements was made at Schlumberger-Doll Research using their 14-MeV pulsed neutron generator and large soil samples. Data were collected after adding iron and nickel to the sample to increase the emission of high-energy lines. Approximately 24 hours of data were accumulated at each of three escape peak window widths. These data were analyzed with RobWin. Combining results from the cruise measurements and the laboratory measurements indicated that both data sets had similar energy dependence and that this energy dependence was different from that obtained using standard Monte Carlo calculations. Alternate methods of simulating the response of the detector to changes in the escape window widths are being investigated.

  11. A Miniature, High-Resolution Laser Radar Operating at Video Rates

    SciTech Connect

    SMITHPETER,COLIN L.; NELLUMS,ROBERT O.; LEBIEN,STEVEN M.; STUDOR,GEORGE

    2000-06-26

    The authors are developing a laser radar to meet the needs of NASA for a 5-lb, 150 in{sup 3} image sensor with a pixel range accuracy of 0.1-inch. NASA applications include structural dynamics measurements, navigation guidance in rendezvous and proximity operations, and space vehicle inspection. The sensor is based on the scannerless range imager architecture developed at Sandia. This architecture modulates laser floodlight illumination and a focal plane receiver to phase encode the laser time of flight (TOF) for each pixel. They believe this approach has significant advantages over architectures directly measuring TOF including high data rate, reduced detector bandwidth, and conventional FPA detection. A limitation of the phase detection technique is its periodic nature, which provides relative range information over a finite ambiguity interval. To extend the operating interval while maintaining a given range resolution, a LADAR sensor using dual modulation frequencies has been developed. This sensor also extends the relative range information to absolute range by calibrating a gating function on the receiver to the TOF. The modulation frequency values can be scaled to meet the resolution and range interval requirements of different applications. Results from the miniature NASA sensor illustrate the advantages of the dual-frequency operation and the ability to provide the range images of 640 by 480 pixels at 30 frames per second.

  12. Stocking Rate Decisions 

    E-print Network

    White, Larry D.; McGinty, Allan

    1999-02-15

    Stocking rate determines animal performance, financial return, and the long-term condition of the range. This publication discusses the factors that affect stocking rate, the relationship of stocking rate to carrying capacity, the amount of forage...

  13. Evaporation Rate on Tungsten

    E-print Network

    Anlage, Steven

    Cesium Evaporation Rate on Tungsten Photocathodes Ameerah Jabr-Hamdan Introduction Motivation Research Objective Experiments Results Conclusions Cesium Evaporation Rate on Tungsten Photocathodes supported by IREAP, with funding from NSF and ONR #12;Cesium Evaporation Rate on Tungsten Photocathodes

  14. Automated Rendezvous and Docking: 1994-2004

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This custom bibliography from the NASA Scientific and Technical Information Program lists a sampling of records found in the NASA Aeronautics and Space Database. The scope of this topic includes technologies for human exploration and robotic sample return missions. This area of focus is one of the enabling technologies as defined by NASA s Report of the President s Commission on Implementation of United States Space Exploration Policy, published in June 2004.

  15. Rendezvous at The Voyages of a

    E-print Network

    Griffiths, Gwyn

    fibre, carbon fibre, ceramics l Energy: Batteries, fuel cells, solar, biological l Robotics: Software: A microscope within Autosub Flow Cytometer Laser sizing Fluorescence Diatom chain (left) with flow cytometer

  16. Discovery: Near-Earth Asteroid Rendezvous (NEAR)

    NASA Technical Reports Server (NTRS)

    Veverka, Joseph

    1992-01-01

    The work carried out under this grant consisted of two parallel studies aimed at defining candidate missions for the initiation of the Discovery Program being considered by NASA's Solar System Exploration Division. The main study considered a Discover-class mission to a Near Earth Asteroid (NEA); the companion study considered a small telescope in Earth-orbit dedicated to ultra violet studies of solar system bodies. The results of these studies are summarized in two reports which are attached (Appendix 1 and Appendix 2).

  17. Telerobotic rendezvous and docking vision system architecture

    NASA Technical Reports Server (NTRS)

    Gravely, Ben; Myers, Donald; Moody, David

    1992-01-01

    This research program has successfully demonstrated a new target label architecture that allows a microcomputer to determine the position, orientation, and identity of an object. It contains a CAD-like database with specific geometric information about the object for approach, grasping, and docking maneuvers. Successful demonstrations were performed selecting and docking an ORU box with either of two ORU receptacles. Small, but significant differences were seen in the two camera types used in the program, and camera sensitive program elements have been identified. The software has been formatted into a new co-autonomy system which provides various levels of operator interaction and promises to allow effective application of telerobotic systems while code improvements are continuing.

  18. 14 CFR 1214.111 - Rendezvous services.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Earth of the orbiting spacecraft (or part thereof), including a spacecraft deployed earlier on the same... orbiting spacecraft to Earth. (3) Revisit of an orbiting spacecraft for purposes such as resupply,...

  19. 14 CFR 1214.111 - Rendezvous services.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Earth of the orbiting spacecraft (or part thereof), including a spacecraft deployed earlier on the same... orbiting spacecraft to Earth. (3) Revisit of an orbiting spacecraft for purposes such as resupply,...

  20. 14 CFR 1214.111 - Rendezvous services.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Earth of the orbiting spacecraft (or part thereof), including a spacecraft deployed earlier on the same... orbiting spacecraft to Earth. (3) Revisit of an orbiting spacecraft for purposes such as resupply,...

  1. Mars Researchers Rendezvous on Remote Arctic Island

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Devon Island is situated in an isolated part of Canada's Nunavut Territory, and is usually considered to be the largest uninhabited island in the world. However, each summer since 1999, researchers from NASA's Haughton-Mars Project and the Mars Society reside at this 'polar desert' location to study the geologic and environmental characteristics of a site which is considered to be an excellent 'Mars analog': a terrestrial location wherein specific conditions approximate environmental features reported on Mars. Base camps established amidst the rocks and rubble surrounding the Haughton impact crater enable researchers to conduct surveys designed to test the habitat, equipment and technology that may be deployed during a human mission to Mars. One of the many objectives of the project scientists is to understand the ice formations around the Haughton area, in the hopes that this might ultimately assist with the recognition of areas where ice can be found at shallow depth on Mars.

    These images of Devon Island from NASA's Multi-angle Imaging SpectroRadiometer (MISR) instrument provide contrasting views of the spectral and angular reflectance 'signatures' of different surfaces within the region. The top panel is a natural color view created with data from the red, green and blue-bands of MISR's nadir (vertical-viewing) camera. The bottom panel is a false-color multiangular composite of the same area, utilizing red band data from MISR's 60-degree backward, nadir, and 60-degree forward-viewing cameras, displayed as red, green and blue, respectively. In this representation, colors highlight textural properties of elements within the scene, with blue tones indicating smooth surfaces (which preferentially forward scatter sunlight) and red hues indicating rougher surfaces (which preferentially backscatter). The angular reflectance 'signature' of low clouds causes them to appear purple, and this visualization provides a unique way of distinguishing clouds from snow and ice.

    The data were captured on June 28, 2001, during the early part of the arctic summer, when sea ice becomes thinner and begins to move depending upon localized currents and winds. In winter the entire region is locked with several meters of nearly motionless sea ice, which acts as a thermodynamic barrier to the loss of heat from the comparatively warm ocean to the colder atmosphere. Summer melting of sea ice can be observed at the two large, dark regions of open water; one is present in the Jones Sound (near the top to the left of center), and another appears in the Wellington Channel (left-hand edge). A large crack caused by tidal heaving has broken the ice cover over the Parry Channel (lower right-hand corner). A substantial ice cap permanently occupies the easternmost third of the island (upper right). Surface features such as dendritic meltwater channels incised into the island's surface are apparent. The Haughton-Mars project site is located slightly to the left and above image center, in an area which appears with relatively little surface ice, near the island's inner 'elbow.'

    The images were acquired during Terra orbit 8132 and cover an area of about 334 kilometers x 229 kilometers. They utilize data from blocks 27 to 31 within World Reference System-2 path 42.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  2. Optical correlators for automated rendezvous and capture

    NASA Technical Reports Server (NTRS)

    Juday, Richard D.

    1991-01-01

    The paper begins with a description of optical correlation. In this process, the propagation physics of coherent light is used to process images and extract information. The processed image is operated on as an area, rather than as a collection of points. An essentially instantaneous convolution is performed on that image to provide the sensory data. In this process, an image is sensed and encoded onto a coherent wavefront, and the propagation is arranged to create a bright spot of the image to match a model of the desired object. The brightness of the spot provides an indication of the degree of resemblance of the viewed image to the mode, and the location of the bright spot provides pointing information. The process can be utilized for AR&C to achieve the capability to identify objects among known reference types, estimate the object's location and orientation, and interact with the control system. System characteristics (speed, robustness, accuracy, small form factors) are adequate to meet most requirements. The correlator exploits the fact that Bosons and Fermions pass through each other. Since the image source is input as an electronic data set, conventional imagers can be used. In systems where the image is input directly, the correlating element must be at the sensing location.

  3. Long range targeting for space based rendezvous

    NASA Technical Reports Server (NTRS)

    Everett, Louis J.; Redfield, R. C.

    1995-01-01

    The work performed under this grant supported the Dexterous Flight Experiment one STS-62 The project required developing hardware and software for automating a TRAC sensor on orbit. The hardware developed by for the flight has been documented through standard NASA channels since it has to pass safety, environmental, and other issues. The software has not been documented previously, therefore, this report provides a software manual for the TRAC code developed for the grant.

  4. Rating Movies and Rating the Raters Who Rate Them.

    PubMed

    Zhou, Hua; Lange, Kenneth

    2009-11-01

    The movie distribution company Netflix has generated considerable buzz in the statistics community by offering a million dollar prize for improvements to its movie rating system. Among the statisticians and computer scientists who have disclosed their techniques, the emphasis has been on machine learning approaches. This article has the modest goal of discussing a simple model for movie rating and other forms of democratic rating. Because the model involves a large number of parameters, it is nontrivial to carry out maximum likelihood estimation. Here we derive a straightforward EM algorithm from the perspective of the more general MM algorithm. The algorithm is capable of finding the global maximum on a likelihood landscape littered with inferior modes. We apply two variants of the model to a dataset from the MovieLens archive and compare their results. Our model identifies quirky raters, redefines the raw rankings, and permits imputation of missing ratings. The model is intended to stimulate discussion and development of better theory rather than to win the prize. It has the added benefit of introducing readers to some of the issues connected with analyzing high-dimensional data. PMID:20802818

  5. Rating Movies and Rating the Raters Who Rate Them

    PubMed Central

    Zhou, Hua; Lange, Kenneth

    2010-01-01

    The movie distribution company Netflix has generated considerable buzz in the statistics community by offering a million dollar prize for improvements to its movie rating system. Among the statisticians and computer scientists who have disclosed their techniques, the emphasis has been on machine learning approaches. This article has the modest goal of discussing a simple model for movie rating and other forms of democratic rating. Because the model involves a large number of parameters, it is nontrivial to carry out maximum likelihood estimation. Here we derive a straightforward EM algorithm from the perspective of the more general MM algorithm. The algorithm is capable of finding the global maximum on a likelihood landscape littered with inferior modes. We apply two variants of the model to a dataset from the MovieLens archive and compare their results. Our model identifies quirky raters, redefines the raw rankings, and permits imputation of missing ratings. The model is intended to stimulate discussion and development of better theory rather than to win the prize. It has the added benefit of introducing readers to some of the issues connected with analyzing high-dimensional data. PMID:20802818

  6. ESTIMATING BIODEGRADATION RATES

    EPA Science Inventory

    This two hour segment of the course reviews the four types of rate constants, illustrates their interactions to produce the behavior of a plume over time, provides representative values of rate constants from the literature, illustrates methods to extract rate constants from fiel...

  7. Handbook of noise ratings

    NASA Technical Reports Server (NTRS)

    Pearsons, K. S.; Bennett, R. L.

    1974-01-01

    The handbook was compiled to provide information in a concise form, describing the multitude of noise rating schemes. It is hoped that by describing the noise rating methods in a single volume the user will have better access to the definitions, application and calculation procedures of the current noise rating methods.

  8. Measuring zebrafish turning rate.

    PubMed

    Mwaffo, Violet; Butail, Sachit; di Bernardo, Mario; Porfiri, Maurizio

    2015-06-01

    Zebrafish is becoming a popular animal model in preclinical research, and zebrafish turning rate has been proposed for the analysis of activity in several domains. The turning rate is often estimated from the trajectory of the fish centroid that is output by commercial or custom-made target tracking software run on overhead videos of fish swimming. However, the accuracy of such indirect methods with respect to the turning rate associated with changes in heading during zebrafish locomotion is largely untested. Here, we compare two indirect methods for the turning rate estimation using the centroid velocity or position data, with full shape tracking for three different video sampling rates. We use tracking data from the overhead video recorded at 60, 30, and 15 frames per second of zebrafish swimming in a shallow water tank. Statistical comparisons of absolute turning rate across methods and sampling rates indicate that, while indirect methods are indistinguishable from full shape tracking, the video sampling rate significantly influences the turning rate measurement. The results of this study can aid in the selection of the video capture frame rate, an experimental design parameter in zebrafish behavioral experiments where activity is an important measure. PMID:25844837

  9. Crude production continues to tumble in the U. S

    SciTech Connect

    Not Available

    1990-02-01

    This article discusses crude oil production in the United States. Production of crude oil and lease condensate in the U.S. fell for the fourth consecutive year in 1989 averaging 7,565,90:00900 bpd or 531,000 bpd (the largest year-to-year decline ever recorded in U.S. history) below 1988 levels. If this trend continues (and there is no reason that it shouldn't) production this year could average below 7 million bpd for the first time since 1958.

  10. Laptops in the Humanities: Classroom Walls Come Tumbling Down

    ERIC Educational Resources Information Center

    Weaver, Barbara E.

    2005-01-01

    This chapter describes successful assignments that made creative use of laptops in writing, literature, and public speaking courses. Some activities moved the session out of the classroom to outdoor locations.

  11. Vesicle tumbling inhibited by inertia Aymen Laadhari,1

    E-print Network

    Saramito, Pierre

    circulatory system the Reynolds number (at the scale of the RBC) is not always small enough for the Stokes constitute a model system for the study of red blood cells (RBCs) dynamics and blood rheology. In the blood,8 correspond to the very small Reynolds numbers limit. However, in the blood circulatory sys- tem, especially

  12. Memory effects in tumbling nematics of 8CB liquid crystals

    E-print Network

    Balaji Yendeti; Ashok Vudaygiri

    2015-05-10

    Particle tracking with a 0.98$\\mu$m silica sphere is used in determining precessional motion of nematic director in nematic phase of 8CB liquid crystals, as it probes those oriented structures which are of the same wavelength as of the sphere size. Velocity auto correlation(VACF) is used in determining those structures in both parallel and perpendicular orientations to the neamatic director. Further, a generic approach by considering the time dependent harmonic oscillator motions is used to analyze the VACF distribution function. This approach leads to observe a transition in the structures of nematic phase that are comparable to transformations from underdamped harmonic oscillator motion to critically damped motion. Also, we measured the microstructural properties and calculated micromechanical properties. The experimental analysis approach used here for 8CB liquid crystals helps to understand and characterize the general dynamic behavior of complex fluids. With this analysis, `dynamics of complex fluids' becomes no more `complex'.

  13. Failed Escape: Solid Surfaces Prevent Tumbling of Escherichia coli

    E-print Network

    Molaei, Mehdi

    Understanding how bacteria move close to surfaces is crucial for a broad range of microbial processes including biofilm formation, bacterial dispersion, and pathogenic infections. We used digital holographic microscopy to ...

  14. The shape and rotation of the tumbling asteroid (99942) Apophis

    NASA Astrophysics Data System (ADS)

    Scheirich, P.; Pravec, P.; Durech, J.; Pollock, J.; Kusnirak, P.; Hornoch, K.; Galad, A.; Jehin, E.; Manfroid, J.; Opitom, C.; Gillon, M.; Colas, F.; Oey, J.; Vrastil, J.; Reichart, D.; Ivarsen, K.; Haislip, J.; LaCluyze, A.

    2014-07-01

    Photometric observations of the asteroid (99942) Apophis taken from December 2012 to April 2013 revealed that it is in a non-principal axis rotation state. We constructed a numerical model of the asteroid's shape and rotation. The asteroid is in a short-axis mode (SAM) of excited rotation. The precession and rotation periods are P_? = 27.38 ± 0.07 h and P_? = 263 ± 6 h, respectively. The rotation is retrograde with the angular momentum vector's ecliptic longitude and latitude of 250° and -75° (the uncertainty area is approximately an ellipse with the major and minor semiaxes of 27° and 14°, respectively). The shape of the asteroid is dynamically close to a prolate ellipsoid, with the lengths of largest and intermediate axes of 1.64 ± 0.09 and 1.14^{+0.04}_{-0.08}, respectively (the shortest axis is normalized to unity); the largest and intermediate moments of inertia differ by 3-4 % only. The asteroid is close to the lowest-energy rotation state, the rotational kinetic energy is greater than the minimum kinetic energy (for rotation around the principal axis with the largest moment of inertia) by only 2-3 %. Despite this low-energy level of excitation, the figure with the two principal moments of inertia nearly equal results in the wobbling angle reaching substantial values of 50-60°.

  15. Take a Tumble: Weathering and Erosion Using a Rock Tumbler

    ERIC Educational Resources Information Center

    Coffey, Patrick; Mattox, Steve

    2006-01-01

    Weathering--the physical and chemical breakdown of geologic materials--and erosion--the transport of materials by wind, water, or ice--can be subtle, yet powerful forces. For example, shale, a rock made of mud-sized particles, is by far the most common sedimentary rock, a testament to the ability of weathering and erosion to take a rock and reduce…

  16. Observed Barium Emission Rates

    NASA Technical Reports Server (NTRS)

    Stenbaek-Nielsen, H. C.; Wescott, E. M.; Hallinan, T. J.

    1993-01-01

    The barium releases from the CRRES satellite have provided an opportunity for verifying theoretically calculated barium ion and neutral emission rates. Spectra of the five Caribbean releases in the summer of 1991 were taken with a spectrograph on board a U.S. Air Force jet aircraft. Because the line of sight release densities are not known, only relative rates could be obtained. The observed relative rates agree well with the theoretically calculated rates and, together with other observations, confirm the earlier detailed theoretical emission rates. The calculated emission rates can thus with good accuracy be used with photometric observations. It has been postulated that charge exchange between neutral barium and oxygen ions represents a significant source for ionization. If so. it should be associated with emissions at 4957.15 A and 5013.00 A, but these emissions were not detected.

  17. Metabolic rate measurement system

    NASA Technical Reports Server (NTRS)

    Koester, K.; Crosier, W.

    1980-01-01

    The Metabolic Rate Measurement System (MRMS) is an uncomplicated and accurate apparatus for measuring oxygen consumption and carbon dioxide production of a test subject. From this one can determine the subject's metabolic rate for a variety of conditions, such as resting or light exercise. MRMS utilizes an LSI/11-03 microcomputer to monitor and control the experimental apparatus.

  18. Target Heart Rates

    MedlinePLUS

    ... you’re ready to determine your target training heart rate. As you exercise, periodically: Take your pulse on the inside of ... safer than others. Learn more: Blood Pressure Vs. Heart Rate The AHA Recommendations ... Receive healthy living tips every month! First Name ( ...

  19. Target Heart Rate Calculator

    MedlinePLUS

    ... workout Enter your age to find a target heart rate during exercise. You'll get the most out of your activities by staying within this range of heartbeats/minute. What is your age? years. How to Check Your Heart Rate Right after you stop exercising, take your pulse: ...

  20. Applications of Reaction Rate

    ERIC Educational Resources Information Center

    Cunningham, Kevin

    2007-01-01

    This article presents an assignment in which students are to research and report on a chemical reaction whose increased or decreased rate is of practical importance. Specifically, students are asked to represent the reaction they have chosen with an acceptable chemical equation, identify a factor that influences its rate and explain how and why it…

  1. Optimal firing rate estimation

    NASA Technical Reports Server (NTRS)

    Paulin, M. G.; Hoffman, L. F.

    2001-01-01

    We define a measure for evaluating the quality of a predictive model of the behavior of a spiking neuron. This measure, information gain per spike (Is), indicates how much more information is provided by the model than if the prediction were made by specifying the neuron's average firing rate over the same time period. We apply a maximum Is criterion to optimize the performance of Gaussian smoothing filters for estimating neural firing rates. With data from bullfrog vestibular semicircular canal neurons and data from simulated integrate-and-fire neurons, the optimal bandwidth for firing rate estimation is typically similar to the average firing rate. Precise timing and average rate models are limiting cases that perform poorly. We estimate that bullfrog semicircular canal sensory neurons transmit in the order of 1 bit of stimulus-related information per spike.

  2. Viral Mutation Rates ?

    PubMed Central

    Sanjuán, Rafael; Nebot, Miguel R.; Chirico, Nicola; Mansky, Louis M.; Belshaw, Robert

    2010-01-01

    Accurate estimates of virus mutation rates are important to understand the evolution of the viruses and to combat them. However, methods of estimation are varied and often complex. Here, we critically review over 40 original studies and establish criteria to facilitate comparative analyses. The mutation rates of 23 viruses are presented as substitutions per nucleotide per cell infection (s/n/c) and corrected for selection bias where necessary, using a new statistical method. The resulting rates range from 10?8 to10?6 s/n/c for DNA viruses and from 10?6 to 10?4 s/n/c for RNA viruses. Similar to what has been shown previously for DNA viruses, there appears to be a negative correlation between mutation rate and genome size among RNA viruses, but this result requires further experimental testing. Contrary to some suggestions, the mutation rate of retroviruses is not lower than that of other RNA viruses. We also show that nucleotide substitutions are on average four times more common than insertions/deletions (indels). Finally, we provide estimates of the mutation rate per nucleotide per strand copying, which tends to be lower than that per cell infection because some viruses undergo several rounds of copying per cell, particularly double-stranded DNA viruses. A regularly updated virus mutation rate data set will be available at www.uv.es/rsanjuan/virmut. PMID:20660197

  3. Chemical Engineering Rate Processes

    E-print Network

    Fenster, Sam

    Chemical Engineering · Rate Processes Physical Chemical Biochemical · Example - pharmacokinetics ocw.mit.edu #12;The historical chemical engineer · Chemistry + Mechanical design of equipment chemical engineer today · Electronics · Pharmaceuticals · Environment - Air, Energy and Water

  4. Rating the Risks.

    ERIC Educational Resources Information Center

    Slovic, Paul; And Others

    1979-01-01

    Explains how people arrive at personal hazard assessments. Explores why people overestimate some hazards and underestimate others. Examines risk ratings for activities and technologies such as nuclear power, motor vehicles, pesticides, and vaccinations. (MA)

  5. 5 Year Rate Changes

    Cancer.gov

    Close Window State Cancer Profiles Quick Reference Guides ? Quick Reference Guides Index 5 Year Rate Changes Send to Printer Text description of this image. Site Home Policies Accessibility Viewing Files FOIA Contact Us U.S. Department of Health and

  6. False call rate estimation

    NASA Astrophysics Data System (ADS)

    Aldrin, John C.; Knopp, Jeremy S.

    2013-01-01

    In this paper, several approaches are presented for the estimation of false call rate including confidence bounds during an NDE reliability study. Bootstrapping methods are applied to nonparametric models (for hit-miss data) and several noise distribution models. By applying bootstrapping with a student t-distribution used to address the "heavy tail" behavior of the data, the estimated false call rate with confidence bounds was found to be in good agreement with the observed data.

  7. Heart Rate Monitor

    NASA Technical Reports Server (NTRS)

    1984-01-01

    In the mid 70's, NASA saw a need for a long term electrocardiographic electrode suitable for use on astronauts. Heart Rate Inc.'s insulated capacitive electrode is constructed of thin dielectric film applied to stainless steel surface, originally developed under a grant by Texas Technical University. HRI, Inc. was awarded NASA license and continued development of heart rate monitor for use on exercise machines for physical fitness and medical markets.

  8. Hydration rate of obsidian.

    PubMed

    Friedman, I; Long, W

    1976-01-30

    The hydration rates of 12 obsidian samples of different chemical compositions were measured at temperatures from 95 degrees to 245 degrees C. An expression relating hydration rate to temperature was derived for each sample. The SiO(2) content and refractive index are related to the hydration rate, as are the CaO, MgO, and original water contents. With this information it is possible to calculate the hydration rate of a sample from its silica content, refractive index, or chemical index and a knowledge of the effective temperature at which the hydration occurred. The effective hydration temperature can be either measured or approximated from weather records. Rates have been calculated by both methods, and the results show that weather records can give a good approximation to the true EHT, particularly in tropical and subtropical climates. If one determines the EHT by any of the methods suggested, and also measures or knows the rate of hydration of the particular obsidian used, it should be possible to carry out absolute dating to +/- 10 percent of the true age over periods as short as several years and as long as millions of years. PMID:17782901

  9. Heart Rate Monitors

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Under a NASA grant, Dr. Robert M. Davis and Dr. William M. Portnoy came up with a new type of electrocardiographic electrode that would enable long term use on astronauts. Their invention was an insulated capacitive electrode constructed of a thin dielectric film. NASA subsequently licensed the electrode technology to Richard Charnitski, inventor of the VersaClimber, who founded Heart Rate, Inc., to further develop and manufacture personal heart monitors and to produce exercise machines using the technology for the physical fitness, medical and home markets. Same technology is on both the Home and Institutional Model VersaClimbers. On the Home Model an infrared heart beat transmitter is worn under exercise clothing. Transmitted heart rate is used to control the work intensity on the VersaClimber using the heart rate as the speedometer of the exercise. This offers advantages to a full range of users from the cardiac rehab patient to the high level physical conditioning of elite athletes. The company manufactures and markets five models of the 1*2*3 HEART RATE monitors that are used wherever people exercise to accurately monitor their heart rate. Company is developing a talking heart rate monitor that works with portable headset radios. A version of the heart beat transmitter will be available to the manufacturers of other aerobic exercise machines.

  10. Rates of spontaneous mutation.

    PubMed Central

    Drake, J W; Charlesworth, B; Charlesworth, D; Crow, J F

    1998-01-01

    Rates of spontaneous mutation per genome as measured in the laboratory are remarkably similar within broad groups of organisms but differ strikingly among groups. Mutation rates in RNA viruses, whose genomes contain ca. 10(4) bases, are roughly 1 per genome per replication for lytic viruses and roughly 0.1 per genome per replication for retroviruses and a retrotransposon. Mutation rates in microbes with DNA-based chromosomes are close to 1/300 per genome per replication; in this group, therefore, rates per base pair vary inversely and hugely as genome sizes vary from 6 x 10(3) to 4 x 10(7) bases or base pairs. Mutation rates in higher eukaryotes are roughly 0.1-100 per genome per sexual generation but are currently indistinguishable from 1/300 per cell division per effective genome (which excludes the fraction of the genome in which most mutations are neutral). It is now possible to specify some of the evolutionary forces that shape these diverse mutation rates. PMID:9560386

  11. Modelling heart rate kinetics.

    PubMed

    Zakynthinaki, Maria S

    2015-01-01

    The objective of the present study was to formulate a simple and at the same time effective mathematical model of heart rate kinetics in response to movement (exercise). Based on an existing model, a system of two coupled differential equations which give the rate of change of heart rate and the rate of change of exercise intensity is used. The modifications introduced to the existing model are justified and discussed in detail, while models of blood lactate accumulation in respect to time and exercise intensity are also presented. The main modification is that the proposed model has now only one parameter which reflects the overall cardiovascular condition of the individual. The time elapsed after the beginning of the exercise, the intensity of the exercise, as well as blood lactate are also taken into account. Application of the model provides information regarding the individual's cardiovascular condition and is able to detect possible changes in it, across the data recording periods. To demonstrate examples of successful numerical fit of the model, constant intensity experimental heart rate data sets of two individuals have been selected and numerical optimization was implemented. In addition, numerical simulations provided predictions for various exercise intensities and various cardiovascular condition levels. The proposed model can serve as a powerful tool for a complete means of heart rate analysis, not only in exercise physiology (for efficiently designing training sessions for healthy subjects) but also in the areas of cardiovascular health and rehabilitation (including application in population groups for which direct heart rate recordings at intense exercises are not possible or not allowed, such as elderly or pregnant women). PMID:25876164

  12. Modelling Heart Rate Kinetics

    PubMed Central

    Zakynthinaki, Maria S.

    2015-01-01

    The objective of the present study was to formulate a simple and at the same time effective mathematical model of heart rate kinetics in response to movement (exercise). Based on an existing model, a system of two coupled differential equations which give the rate of change of heart rate and the rate of change of exercise intensity is used. The modifications introduced to the existing model are justified and discussed in detail, while models of blood lactate accumulation in respect to time and exercise intensity are also presented. The main modification is that the proposed model has now only one parameter which reflects the overall cardiovascular condition of the individual. The time elapsed after the beginning of the exercise, the intensity of the exercise, as well as blood lactate are also taken into account. Application of the model provides information regarding the individual’s cardiovascular condition and is able to detect possible changes in it, across the data recording periods. To demonstrate examples of successful numerical fit of the model, constant intensity experimental heart rate data sets of two individuals have been selected and numerical optimization was implemented. In addition, numerical simulations provided predictions for various exercise intensities and various cardiovascular condition levels. The proposed model can serve as a powerful tool for a complete means of heart rate analysis, not only in exercise physiology (for efficiently designing training sessions for healthy subjects) but also in the areas of cardiovascular health and rehabilitation (including application in population groups for which direct heart rate recordings at intense exercises are not possible or not allowed, such as elderly or pregnant women). PMID:25876164

  13. Interest rates factor model

    NASA Astrophysics Data System (ADS)

    Lee, Sangwook; Kim, Min Jae; Kim, Soo Yong

    2011-07-01

    Interdependence of the interest rates of the US, the UK, and Japan is analyzed in this work by means of spectral analysis and network methods. A predominant effective factor in the interest rate market is which country floats a bond issue, and a minor effective factor is time to maturity of bonds. Power-law cross-correlation among different countries is analyzed by the detrended cross-correlation analysis method. Long-range cross-correlation is found between the first factors of interest rate, while there is no cross-correlation between some of the second factors. The tail dependency is indicated by tail indices from Archimedean copulas, including an empirical copula. In contrast to other pairs, the US-UK first factor pair has tail dependencies in both the upper-tail and lower-tail. Dynamic properties of interest rate are modeled by a stochastic volatility model. The properties of mean reverting and volatility clustering are observed and reflected in this model. The proposed simulation method combines the dependence structures and the factor dynamics model; it simultaneously describes the interest rates of different countries.

  14. Heart rate turbulence.

    PubMed

    Cygankiewicz, Iwona

    2013-01-01

    Heart rate turbulence (HRT) is a baroreflex-mediated biphasic reaction of heart rate in response to premature ventricular beats. Heart rate turbulence is quantified by: turbulence onset (TO) reflecting the initial acceleration of heart rate following premature beat and turbulence slope (TS) describing subsequent deceleration of heart rate. Abnormal HRT identifies patients with autonomic dysfunction or impaired baroreflex sensitivity due to variety of disorders, but also may reflect changes in autonomic nervous system induced by different therapeutic modalities such as drugs, revascularization, or cardiac resynchronization therapy. More importantly, impaired HRT has been shown to identify patients at high risk of all-cause mortality and sudden death, particularly in postinfarction and congestive heart failure patients. It should be emphasized that abnormal HRT has a well-established role in stratification of postinfarction and heart failure patients with relatively preserved left ventricular ejection fraction. The ongoing clinical trials will document whether HRT can be used to guide implantation of cardioverter-defibrillators in this subset of patients, not covered yet by ICD guidelines. This review focuses on the current state-of-the-art knowledge regarding clinical significance of HRT in detection of autonomic dysfunction and regarding the prognostic significance of this parameter in predicting all-cause mortality and sudden death. PMID:24215748

  15. Optical rate sensor algorithms

    NASA Technical Reports Server (NTRS)

    Uhde-Lacovara, Jo A.

    1989-01-01

    Optical sensors, in particular Charge Coupled Device (CCD) arrays, will be used on Space Station to track stars in order to provide inertial attitude reference. Algorithms are presented to derive attitude rate from the optical sensors. The first algorithm is a recursive differentiator. A variance reduction factor (VRF) of 0.0228 was achieved with a rise time of 10 samples. A VRF of 0.2522 gives a rise time of 4 samples. The second algorithm is based on the direct manipulation of the pixel intensity outputs of the sensor. In 1-dimensional simulations, the derived rate was with 0.07 percent of the actual rate in the presence of additive Gaussian noise with a signal to noise ratio of 60 dB.

  16. Selfing rate Expectedproportion

    E-print Network

    Reece, Sarah

    Selfing rate Clones Expectedproportion malegametocytes(%) f = 1 f = 2 f = 3 f = 4 f = 6 f = 8 0 0, aggressive therapy, identify patients for clinical trials, and develop new therapeutic approaches of a single genotype, or clone, of parasites, the optimal sex ratio for that clone would be one male

  17. Paradoxes in Film Ratings

    ERIC Educational Resources Information Center

    Moore, Thomas L.

    2006-01-01

    The author selected a simple random sample of 100 movies from the "Movie and Video Guide" (1996), by Leonard Maltin. The author's intent was to obtain some basic information on the population of roughly 19,000 movies through a small sample. The "Movie and Video Guide" by Leonard Maltin is an annual ratings guide to movies. While not all films ever…

  18. increasing job placement rates

    E-print Network

    Wu, Mingshen

    2: Work & Personality Module 3: Critical Thinking Module 4: Use of Social Media Module 5: Job;Social Networking Social Media's prevalence Good uses of social media (you can still be on Facebookincreasing job placement rates for STEM students with disabilities Laura McCullough, Kathleen Deery

  19. Variable rate irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Systems are available to producers to make variable-rate applications of defoliants, fertilizer, lime, pesticides, plant growth regulators, and seed. These systems could potentially offer cost savings to a producer; however, the full potential of the benefits and savings cannot be realized if water ...

  20. Variable Rate Irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Systems are available to producers with the ability to make variable-rate applications of defoliants, fertilizer, lime, pesticides, plant growth regulators, and seed. These systems could potentially offer a producer great cost savings; however, the full potential of these benefits and savings cannot...

  1. Currency Exchange Rates.

    ERIC Educational Resources Information Center

    Siler, Carl R.

    This curriculum unit of the Muncie (Indiana) Southside High School is to simulate the dynamics of foreign currency exchange rates from the perspectives of: (1) a major U.S. corporation, ABB Power T & D Company, Inc., of Muncie, Indiana, a manufacturer of large power transformers for the domestic and foreign markets; and (2) individual consumers…

  2. Toy Stories: Modeling Rates

    ERIC Educational Resources Information Center

    Swanson, Patricia E.

    2015-01-01

    Elementary school mathematics is increasingly recognized for its crucial role in developing the foundational skills and understandings for algebra. In this article, the author uses a lesson to introduce the concept of "rates"--comparing two different types and units of measure--and how to graph them. Described is the lesson and shared…

  3. Calculating California Seismicity Rates

    USGS Publications Warehouse

    Felzer, Karen R.

    2008-01-01

    Empirically the rate of earthquakes = magnitude M is well fit by the Gutenberg-Richter relationship, logN=a-bM (1) where N is the number of earthquakes = M over a given time period, a is the number of M = 0 earthquakes over the same period, and b is a parameter that determines the ratio of larger to smaller earthquakes (Ishimoto and Iida 1939; Gutenberg and Richter 1944). Thus to characterize the seismicity rate, N, and risk in a given region we need to solve for the values of a and b. Here we are concerned with solving for the long term average values of these parameters for the state of California. My primary data source is a catalog of 1850-2006 M = 4.0 seismicity compiled with Tianqing Cao (Appendix H). Because earthquakes outside of the state can influence California I consider both earthquakes within the state and within 100 km of the state border (Figure 1).

  4. Rotational rate sensor

    DOEpatents

    Hunter, Steven L. (Livermore, CA)

    2002-01-01

    A rate sensor for angular/rotational acceleration includes a housing defining a fluid cavity essentially completely filled with an electrolyte fluid. Within the housing, such as a toroid, ions in the fluid are swept during movement from an excitation electrode toward one of two output electrodes to provide a signal for directional rotation. One or more ground electrodes within the housing serve to neutralize ions, thus preventing any effect at the other output electrode.

  5. 29 CFR 778.112 - Day rates and job rates.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Day rates and job rates. 778.112 Section 778.112 Labor... Requirements Principles for Computing Overtime Pay Based on the âregular Rateâ § 778.112 Day rates and job rates. If the employee is paid a flat sum for a day's work or for doing a particular job, without...

  6. 29 CFR 778.112 - Day rates and job rates.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Day rates and job rates. 778.112 Section 778.112 Labor... Requirements Principles for Computing Overtime Pay Based on the âregular Rateâ § 778.112 Day rates and job rates. If the employee is paid a flat sum for a day's work or for doing a particular job, without...

  7. 29 CFR 778.112 - Day rates and job rates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Day rates and job rates. 778.112 Section 778.112 Labor... Requirements Principles for Computing Overtime Pay Based on the âregular Rateâ § 778.112 Day rates and job rates. If the employee is paid a flat sum for a day's work or for doing a particular job, without...

  8. 29 CFR 778.112 - Day rates and job rates.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Day rates and job rates. 778.112 Section 778.112 Labor... Requirements Principles for Computing Overtime Pay Based on the âregular Rateâ § 778.112 Day rates and job rates. If the employee is paid a flat sum for a day's work or for doing a particular job, without...

  9. 29 CFR 778.112 - Day rates and job rates.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false Day rates and job rates. 778.112 Section 778.112 Labor... Requirements Principles for Computing Overtime Pay Based on the âregular Rateâ § 778.112 Day rates and job rates. If the employee is paid a flat sum for a day's work or for doing a particular job, without...

  10. Heart-Rate and Breath-Rate Monitor

    NASA Technical Reports Server (NTRS)

    Cooper, T. G.

    1983-01-01

    Circuit requiring only four integrated circuits (IC's) measures both heart rate and breath rate. Phase-locked loops lock on heart-rate and respiration-rate input signals. Each loop IC contains two phase comparators. Positive-edge-triggered circuit used in making monitors insensitive to dutycycle variations.

  11. Method and associated apparatus for capturing, servicing, and de-orbiting earth satellites using robotics

    NASA Technical Reports Server (NTRS)

    Cepollina, Frank J. (Inventor); Burns, Richard D. (Inventor); Holz, Jill M. (Inventor); Corbo, James E. (Inventor); Jedhrich, Nicholas M. (Inventor)

    2009-01-01

    This invention is a method and supporting apparatus for autonomously capturing, servicing and de-orbiting a free-flying spacecraft, such as a satellite, using robotics. The capture of the spacecraft includes the steps of optically seeking and ranging the satellite using LIDAR; and matching tumble rates, rendezvousing and berthing with the satellite. Servicing of the spacecraft may be done using supervised autonomy, which is allowing a robot to execute a sequence of instructions without intervention from a remote human-occupied location. These instructions may be packaged at the remote station in a script and uplinked to the robot for execution upon remote command giving authority to proceed. Alternately, the instructions may be generated by Artificial Intelligence (AI) logic onboard the robot. In either case, the remote operator maintains the ability to abort an instruction or script at any time, as well as the ability to intervene using manual override to teleoperate the robot.In one embodiment, a vehicle used for carrying out the method of this invention comprises an ejection module, which includes the robot, and a de-orbit module. Once servicing is completed by the robot, the ejection module separates from the de-orbit module, leaving the de-orbit module attached to the satellite for de-orbiting the same at a future time. Upon separation, the ejection module can either de-orbit itself or rendezvous with another satellite for servicing. The ability to de-orbit a spacecraft further allows the opportunity to direct the landing of the spent satellite in a safe location away from population centers, such as the ocean.

  12. Method and associated apparatus for capturing, servicing and de-orbiting earth satellites using robotics

    NASA Technical Reports Server (NTRS)

    Cepollina, Frank J. (Inventor); Burns, Richard D. (Inventor); Holz, Jill M. (Inventor); Corbo, James E. (Inventor); Jedhrich, Nicholas M. (Inventor)

    2008-01-01

    This invention is a method and supporting apparatus for autonomously capturing, servicing and de-orbiting a free-flying spacecraft, such as a satellite, using robotics. The capture of the spacecraft includes the steps of optically seeking and ranging the satellite using LIDAR; and matching tumble rates, rendezvousing and berthing with the satellite. Servicing of the spacecraft may be done using supervised autonomy, which is allowing a robot to execute a sequence of instructions without intervention from a remote human-occupied location. These instructions may be packaged at the remote station in a script and uplinked to the robot for execution upon remote command giving authority to proceed. Alternately, the instructions may be generated by Artificial Intelligence (AI) logic onboard the robot. In either case, the remote operator maintains the ability to abort an instruction or script at any time, as well as the ability to intervene using manual override to teleoperate the robot.In one embodiment, a vehicle used for carrying out the method of this invention comprises an ejection module, which includes the robot, and a de-orbit module. Once servicing is completed by the robot, the ejection module separates from the de-orbit module, leaving the de-orbit module attached to the satellite for de-orbiting the same at a future time. Upon separation, the ejection module can either de-orbit itself or rendezvous with another satellite for servicing. The ability to de-orbit a spacecraft further allows the opportunity to direct the landing of the spent satellite in a safe location away from population centers, such as the ocean.

  13. Method and associated apparatus for capturing, servicing and de-orbiting earth satellites using robotics

    NASA Technical Reports Server (NTRS)

    Cepollina, Frank J. (Inventor); Burns, Richard D. (Inventor); Holz, Jill M. (Inventor); Corbo, James E. (Inventor); Jedhrich, Nicholas M. (Inventor)

    2007-01-01

    This invention is a method and supporting apparatus for autonomously capturing, servicing and de-orbiting a free-flying spacecraft, such as a satellite, using robotics. The capture of the spacecraft includes the steps of optically seeking and ranging the satellite using LIDAR; and matching tumble rates, rendezvousing and berthing with the satellite. Servicing of the spacecraft may be done using supervised autonomy, which is allowing a robot to execute a sequence of instructions without intervention from a remote human-occupied location. These instructions may be packaged at the remote station in a script and uplinked to the robot for execution upon remote command giving authority to proceed. Alternately, the instructions may be generated by Artificial Intelligence (AI) logic onboard the robot. In either case, the remote operator maintains the ability to abort an instruction or script at any time, as well as the ability to intervene using manual override to teleoperate the robot.In one embodiment, a vehicle used for carrying out the method of this invention comprises an ejection module, which includes the robot, and a de-orbit module. Once servicing is completed by the robot, the ejection module separates from the de-orbit module, leaving the de-orbit module attached to the satellite for de-orbiting the same at a future time. Upon separation, the ejection module can either de-orbit itself or rendezvous with another satellite for servicing. The ability to de-orbit a spacecraft further allows the opportunity to direct the landing of the spent satellite in a safe location away from population centers, such as the ocean.

  14. Method and associated apparatus for capturing, servicing, and de-orbiting earth satellites using robotics

    NASA Technical Reports Server (NTRS)

    Cepollina, Frank J. (Inventor); Burns, Richard D. (Inventor); Holz, Jill M. (Inventor); Corbo, James E. (Inventor); Jedhrich, Nicholas M. (Inventor)

    2007-01-01

    This invention is a method and supporting apparatus for autonomously capturing, servicing and de-orbiting a free-flying spacecraft, such as a satellite, using robotics. The capture of the spacecraft includes the steps of optically seeking and ranging the satellite using LIDAR; and matching tumble rates, rendezvousing and berthing with the satellite. Servicing of the spacecraft may be done using supervised autonomy, which is allowing a robot to execute a sequence of instructions without intervention from a remote human-occupied location. These instructions may be packaged at the remote station in a script and uplinked to the robot for execution upon remote command giving authority to proceed. Alternately, the instructions may be generated by Artificial Intelligence (AI) logic onboard the robot. In either case, the remote operator maintains the ability to abort an instruction or script at any time, as well as the ability to intervene using manual override to teleoperate the robot.In one embodiment, a vehicle used for carrying out the method of this invention comprises an ejection module, which includes the robot, and a de-orbit module. Once servicing is completed by the robot, the ejection module separates from the de-orbit module, leaving the de-orbit module attached to the satellite for de-orbiting the same at a future time. Upon separation, the ejection module can either de-orbit itself or rendezvous with another satellite for servicing. The ability to de-orbit a spacecraft further allows the opportunity to direct the landing of the spent satellite in a safe location away from population centers, such as the ocean.

  15. Survival Rates and Consequences

    NASA Astrophysics Data System (ADS)

    Whitmore, B. C.

    2004-12-01

    To first order, the initial cluster luminosity function appears to be universal. This means that the brightest young cluster in a galaxy can be predicted from the total number of young clusters based purely on statistics. This suggests that the physical processes responsible for the formation of clusters are similar in a wide variety of galaxies, from mergers to quiescent spirals. One possibility is that conditions for making young massive clusters are globally present in mergers while only locally present in spirals (i.e., in the spiral arms). However, understanding the destruction of clusters and the accompanying survival rates is more important for understanding cluster demographics than understanding their formation. This is because only about 1 in 1,000 clusters with mass greater than 104 M? will survive to become an old globular cluster. In this paper we briefly review this basic framework and then develop a toy model that allows us to begin to address several fundamental questions. In particular, we demonstrate that young clusters in the Antennae Galaxies have a high ``infant mortality'' rate, with roughly 90 % of the clusters being destroyed each decade of log(time). We also advocate the use of an objective classification system for clusters, with the three parameters being mass, age, and size.

  16. Sequential Effects in Essay Ratings

    ERIC Educational Resources Information Center

    Attali, Yigal

    2011-01-01

    Contrary to previous research on sequential ratings of student performance, this study found that professional essay raters of a large-scale standardized testing program produced ratings that were drawn toward previous ratings, creating an assimilation effect. Longer intervals between the two adjacent ratings and higher degree of agreement with…

  17. 76 FR 38207 - Fee Rate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-29

    ... COMMISSION Fee Rate AGENCY: National Indian Gaming Commission. ACTION: Notice. SUMMARY: Notice is hereby... annual fee rates of 0.00% for tier 1 and 0.074% (.00074) for tier 2 for calendar year 2011. These rates... Commission. If a tribe has a certificate of self-regulation under 25 CFR part 518, the final fee rate...

  18. 78 FR 14821 - Fee Rate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-07

    ... National Indian Gaming Commission Fee Rate AGENCY: National Indian Gaming Commission, Interior. ACTION... Commission has adopted its 2013 preliminary annual fee rates of 0.00% for tier 1 and 0.074% (.00074) for tier... preliminary fee rate on Class II revenues shall be one-half of the annual fee rate, which is 0.037%...

  19. 75 FR 5342 - Fee Rate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-02

    ... COMMISSION Fee Rate AGENCY: National Indian Gaming Commission. ACTION: Notice. SUMMARY: Notice is hereby... preliminary annual fee rates of 0.00% for tier 1 and 0.060% (.00060) for tier 2 for calendar year 2010. These... fee rate on class II revenues for calendar year 2010 shall be one-half of the annual fee rate,...

  20. 77 FR 5267 - Fee Rate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-02

    ... COMMISSION Fee Rate AGENCY: National Indian Gaming Commission. ACTION: Notice. SUMMARY: Notice is hereby... preliminary annual fee rates of 0.00% for tier 1 and 0.074% (.00074) for tier 2 for calendar year 2012. These... fee rate on class II revenues for calendar year 2012 shall be one-half of the annual fee rate,...

  1. 77 FR 41202 - Fee Rate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-12

    ... COMMISSION Fee Rate AGENCY: National Indian Gaming Commission. ACTION: Notice. SUMMARY: Notice is hereby... annual fee rates of 0.00% for tier 1 and 0.074% (.00074) for tier 2 for calendar year 2012. These rates... Commission. If a Tribe has a certificate of self-regulation under 25 CFR part 518, the final fee rate...

  2. 76 FR 7879 - Fee Rate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-11

    ... COMMISSION Fee Rate AGENCY: National Indian Gaming Commission. ACTION: Notice. SUMMARY: Notice is hereby... preliminary annual fee rates of 0.00% for tier 1 and 0.074% (.00074) for tier 2 for calendar year 2011. These... fee rate on class II revenues for calendar year 2011 shall be one-half of the annual fee rate,...

  3. 76 FR 8946 - Security Ratings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-16

    ... COMMISSION 17 CFR Parts 200, 229, 230, 232, 239, 240, and 249 RIN 3235-AK18 Security Ratings AGENCY... will be considering relating to the use of security ratings by credit rating agencies in our rules and... that rely on, or make special accommodations for, security ratings (for example, Forms S-3 and...

  4. Lindblad rate equations

    SciTech Connect

    Budini, Adrian A.

    2006-11-15

    In this paper we derive an extra class of non-Markovian master equations where the system state is written as a sum of auxiliary matrixes whose evolution involve Lindblad contributions with local coupling between all of them, resembling the structure of a classical rate equation. The system dynamics may develop strong nonlocal effects such as the dependence of the stationary properties with the system initialization. These equations are derived from alternative microscopic interactions, such as complex environments described in a generalized Born-Markov approximation and tripartite system-environment interactions, where extra unobserved degrees of freedom mediates the entanglement between the system and a Markovian reservoir. Conditions that guarantee the completely positive condition of the solution map are found. Quantum stochastic processes that recover the system dynamics in average are formulated. We exemplify our results by analyzing the dynamical action of nontrivial structured dephasing and depolarizing reservoirs over a single qubit.

  5. High accuracy optical rate sensor

    NASA Technical Reports Server (NTRS)

    Uhde-Lacovara, J.

    1990-01-01

    Optical rate sensors, in particular CCD arrays, will be used on Space Station Freedom to track stars in order to provide inertial attitude reference. An algorithm to provide attitude rate information by directly manipulating the sensor pixel intensity output is presented. The star image produced by a sensor in the laboratory is modeled. Simulated, moving star images are generated, and the algorithm is applied to this data for a star moving at a constant rate. The algorithm produces accurate derived rate of the above data. A step rate change requires two frames for the output of the algorithm to accurately reflect the new rate. When zero mean Gaussian noise with a standard deviation of 5 is added to the simulated data of a star image moving at a constant rate, the algorithm derives the rate with an error of 1.9 percent at a rate of 1.28 pixels per frame.

  6. Rate & Detection Rate Age & Time Since Previous Mammography

    Cancer.gov

    Skip to Main Content Home   |   Data   |   Statistics   |   Tools   |   Collaborations   |   Work with Us   |   Publications   |   About   |   Links Cancer Rate (per 1,000 examinations) and Cancer Detection Rate (per 1,000 examinations) for 3,884,059

  7. Rate & Detection Rate by Time Since Previous Mammography

    Cancer.gov

    Skip to Main Content Home   |   Data   |   Statistics   |   Tools   |   Collaborations   |   Work with Us   |   Publications   |   About   |   Links Cancer Rate (per 1,000 examinations) and Cancer Detection Rate (per 1,000 examinations) for 3,884,059

  8. Rate & Detection Rate Age & Time Since Previous Mammography

    Cancer.gov

    Skip to Main Content Home   |   Data   |   Statistics   |   Tools   |   Collaborations   |   Work with Us   |   Publications   |   About   |   Links Cancer Rate (per 1,000 examinations) and Cancer Detection Rate (per 1,000 examinations) for 1,838,372

  9. Rate & Detection Rate by Time Since Previous Mammography

    Cancer.gov

    Skip to Main Content Home   |   Data   |   Statistics   |   Tools   |   Collaborations   |   Work with Us   |   Publications   |   About   |   Links Cancer Rate (per 1,000 examinations) and Cancer Detection Rate (per 1,000 examinations) for 1,838,372

  10. National Utility Rate Database: Preprint

    SciTech Connect

    Ong, S.; McKeel, R.

    2012-08-01

    When modeling solar energy technologies and other distributed energy systems, using high-quality expansive electricity rates is essential. The National Renewable Energy Laboratory (NREL) developed a utility rate platform for entering, storing, updating, and accessing a large collection of utility rates from around the United States. This utility rate platform lives on the Open Energy Information (OpenEI) website, OpenEI.org, allowing the data to be programmatically accessed from a web browser, using an application programming interface (API). The semantic-based utility rate platform currently has record of 1,885 utility rates and covers over 85% of the electricity consumption in the United States.

  11. Intramolecular electron transfer rates

    NASA Astrophysics Data System (ADS)

    Hupp, Joseph T.

    The initial goals of this project were: (1) to construct pulsed-accelerated-flow and pulsed-laser (transient absorbance) instruments for intramolecular electron-transfer rate measurements, (2) to design and synthesize appropriate molecules and perform such measurements, (3) to develop further an electrochemical method for gauging site-to-site electronic coupling, and (4) to apply time-dependent Raman scattering theory to the problem of inner-shell reorganization in charge-transfer reactions. Although all four goals were met, we also found it necessary to pursue studies in some unforeseen directions. For example, early on we discovered that medium effects (aggregation and ion pairing) could play a very large, and previously unrecognized, role in some optical intervalence reactions. Given the importance of the effects to the areas above, we chose to map them in a fairly complete fashion. Also, in anticipation of possible renewal we initiated studies in a new area: bimolecular photoredox kinetics in supercritical media. Finally, in a small project carried out largely by undergraduates we examined solvent tuning effects upon lifetimes of photo-excited ruthenium am(m)ine bipyridine complexes. The key new findings and other highlights of these studies are outlined.

  12. Rates of Earth degassing

    NASA Technical Reports Server (NTRS)

    Onions, R. K.

    1994-01-01

    The degassing of the Earth during accretion is constrained by Pu-U-I-Xe systematics. Degassing was much more efficient during the first 100-200 Ma than subsequently, and it was more complete for Xe than for the lighter gases. More than 90 percent of the degassed Xe escaped from the atmosphere during this period. The combination of fractional degassing of melts and rare gas escape from the atmosphere is able to explain the deficit of terrestrial Xe as a simple consequence of this early degassing history. By the time Xe was quantitatively retained in the atmosphere, the abundances of Kr and the lighter gases in the Earth's interior were similar to or higher than the present-day atmospheric abundances. Subsequent transfer of these lighter rare gases into the atmosphere requires a high rate of post-accretion degassing and melt production. Considerations of Pu-U-Xe systematics suggest that relatively rapid post-accretion degassing was continued to ca. 4.1-4.2 Ga. The present-day degassing history of the Earth is investigated through consideration of rare gas isotope abundances. Although the Earth is a highly degassed body, depleted in rare gases by many orders of magnitude relative to their solar abundances, it is at the present-day losing primordial rare gases which were trapped at the time of accretion.

  13. LEED for Homes Rating System affordablemarket rate multi-family

    E-print Network

    Zaferatos, Nicholas C.

    LEED for Homes Rating System affordablemarket rate multi-family #12;The top 25% of new homes based the negative impact of buildings on their occupants and on the environment. LEED for Homes categories and education (AE) #12;Rating System www.usgbc.org/leed/homes #12;LEED for Homes Project Checklist or Scorecard

  14. All about Heart Rate (Pulse)

    MedlinePLUS

    ... Pressure High Blood Pressure Tools & Resources Stroke More All About Heart Rate (Pulse) Updated:Aug 5,2015 ... are the Symptoms of High Blood Pressure? 4 All About Heart Rate (Pulse) 5 Heart Attack Symptoms ...

  15. SCHOOL OF MEDICINE TELECOMMUNICATIONS RATE

    E-print Network

    Kay, Mark A.

    SCHOOL OF MEDICINE TELECOMMUNICATIONS RATE BACKGROUND The University recently the desktop phone service costs back to individual units/departments by creating a telecommunications rate in the Other Expenses category of the budget as a "Telecommunications Charge". NOTE- direct charging

  16. Lung Cancer Rates by State

    MedlinePLUS

    ... HPV-Associated Ovarian Prostate Skin Uterine Cancer Home Lung Cancer Rates by State Language: English Espańol (Spanish) Recommend ... which statistics are currently available). Rates of Getting Lung Cancer by State The number of people who get ...

  17. Breast Cancer Rates by State

    MedlinePLUS

    ... Associated Lung Ovarian Prostate Skin Uterine Cancer Home Breast Cancer Rates by State Language: English Espańol (Spanish) Recommend ... from breast cancer each year. Rates of Getting Breast Cancer by State The number of people who get ...

  18. 2007 Wholesale Power Rate Schedules : 2007 General Rate Schedule Provisions.

    SciTech Connect

    United States. Bonneville Power Administration.

    2006-11-01

    This schedule is available for the contract purchase of Firm Power to be used within the Pacific Northwest (PNW). Priority Firm (PF) Power may be purchased by public bodies, cooperatives, and Federal agencies for resale to ultimate consumers, for direct consumption, and for Construction, Test and Start-Up, and Station Service. Rates in this schedule are in effect beginning October 1, 2006, and apply to purchases under requirements Firm Power sales contracts for a three-year period. The Slice Product is only available for public bodies and cooperatives who have signed Slice contracts for the FY 2002-2011 period. Utilities participating in the Residential Exchange Program (REP) under Section 5(c) of the Northwest Power Act may purchase Priority Firm Power pursuant to the Residential Exchange Program. Rates under contracts that contain charges that escalate based on BPA's Priority Firm Power rates shall be based on the three-year rates listed in this rate schedule in addition to applicable transmission charges. This rate schedule supersedes the PF-02 rate schedule, which went into effect October 1, 2001. Sales under the PF-07 rate schedule are subject to BPA's 2007 General Rate Schedule Provisions (2007 GRSPs). Products available under this rate schedule are defined in the 2007 GRSPs. For sales under this rate schedule, bills shall be rendered and payments due pursuant to BPA's 2007 GRSPs and billing process.

  19. 75 FR 44807 - Fee Rate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-29

    ... COMMISSION Fee Rate AGENCY: National Indian Gaming Commission. ACTION: Notice. SUMMARY: Notice is hereby... annual fee rates of 0.00% for tier 1 and 0.060% (.00060) for tier 2 for calendar year 2010. These rates... Commission. If a tribe has a certificate of self-regulation under 25 CFR part 518, the preliminary fee...

  20. MEMS Rate Sensors for Space

    NASA Technical Reports Server (NTRS)

    Gambino, Joel P.

    1999-01-01

    Micromachined Electro Mechanical System Rate sensors offer many advantages that make them attractive for space use. They are smaller, consume less power, and cost less than the systems currently available. MEMS Rate Sensors however, have not been optimized for use on spacecraft. This paper describes an approach to developing MEMS Rate Sensors systems for space use.

  1. Rate and Occupancy Survey Results.

    ERIC Educational Resources Information Center

    Mid-Atlantic Association of Coll. and Univ. Housing Officers.

    In its annual effort to determine rate and occupancy trends in the Mid-Atlantic region, MACUHO surveyed by questionnaire the chief housing officers on its mailing list and received 99 usable responses, compared with 65 the previous year. The average double room rate was reported to be $691, compared with $646 in 1975; the average board rate rose…

  2. Transportation Rates For Fishery Products

    E-print Network

    Indexes of Transportation Rates For Fishery Products Fish and Wildlife Service United States Department of the Interior #12;#12;Indexes of Transportation Rates For Fishery Products B7 Morton J. Garfield carriers: Indexes of rates on fishery products, by years, 1947-52 13 8. Fishery products transported

  3. Stocking Rates for Horse Pastures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Decision on which stocking rate to graze a horse pasture is critical, particularly if the forage is expected to meet the nutrient needs of the horses. Challenges and management for targeting the optimum stocking rate, defined as the stocking rate that allows forage consumption to approximately equ...

  4. AGRICULTURAL EXCHANGE RATE DATA SHEET

    EPA Science Inventory

    The ERS data set contains annual and monthly data for exchange rates important to U.S. agriculture. It includes both nominal and real exchange rates for 80 countries (plus the European Union) as well as real trade-weighted exchange rate indexes for many commodities and aggregatio...

  5. Factors Related to Reading Rates.

    ERIC Educational Resources Information Center

    Hanson, Earl

    1968-01-01

    A summary of research on reading rate is presented. Cited studies dating from 1884 to 1965 suggest a relationship among reading rate and visual perception, practice in reading, power of concentration, mental alertness, complex reaction times, intelligence, amount of vocalization, content, rate of thinking, intensity of illumination, typographical…

  6. Discharge ratings at gaging stations

    USGS Publications Warehouse

    Kennedy, E.J.

    1984-01-01

    A discharge rating is the relation of the discharge at a gaging station to stage and sometimes also to other variables. This chapter of 'Techniques of Water-Resources Investigations' describes the procedures commonly used to develop simple ratings where discharge is related only to stage and the most frequently encountered types of complex ratings where additional factors such as rate of change in stage, water-surface slope, or index velocity are used. Fundamental techniques of logarithmic plotting and the applications of simple storage routing to rating development are demonstrated. Computer applications, especially for handheld programmable calculators, and data handling are stressed.

  7. The Inverted Block Rate:The Inverted Block Rate: An Alternative to Flat Rate BillingAn Alternative to Flat Rate Billing

    E-print Network

    Hughes, Larry

    The Inverted Block Rate:The Inverted Block Rate: An Alternative to Flat Rate BillingAn Alternative;Inverted Block RateInverted Block Rate 22 IntroductionIntroduction ·· Modern societies rely on electrical collectionMetering and Rate Models facilitate collection #12;Inverted Block RateInverted Block Rate 33 Rate

  8. Advancing Lidar Sensors Technologies for Next Generation Landing Missions

    NASA Technical Reports Server (NTRS)

    Amzajerdian, Farzin; Hines, Glenn D.; Roback, Vincent E.; Petway, Larry B.; Barnes, Bruce W.; Brewster, Paul F.; Pierrottet, Diego F.; Bulyshev, Alexander

    2015-01-01

    Missions to solar systems bodies must meet increasingly ambitious objectives requiring highly reliable "precision landing", and "hazard avoidance" capabilities. Robotic missions to the Moon and Mars demand landing at pre-designated sites of high scientific value near hazardous terrain features, such as escarpments, craters, slopes, and rocks. Missions aimed at paving the path for colonization of the Moon and human landing on Mars need to execute onboard hazard detection and precision maneuvering to ensure safe landing near previously deployed assets. Asteroid missions require precision rendezvous, identification of the landing or sampling site location, and navigation to the highly dynamic object that may be tumbling at a fast rate. To meet these needs, NASA Langley Research Center (LaRC) has developed a set of advanced lidar sensors under the Autonomous Landing and Hazard Avoidance Technology (ALHAT) project. These lidar sensors can provide precision measurement of vehicle relative proximity, velocity, and orientation, and high resolution elevation maps of the surface during the descent to the targeted body. Recent flights onboard Morpheus free-flyer vehicle have demonstrated the viability of ALHAT lidar sensors for future landing missions to solar system bodies.

  9. Female Literacy Rate is a Better Predictor of Birth Rate and Infant Mortality Rate in India

    PubMed Central

    Saurabh, Suman; Sarkar, Sonali; Pandey, Dhruv K.

    2013-01-01

    Background: Educated women are known to take informed reproductive and healthcare decisions. These result in population stabilization and better infant care reflected by lower birth rates and infant mortality rates (IMRs), respectively. Materials and Methods: Our objective was to study the relationship of male and female literacy rates with crude birth rates (CBRs) and IMRs of the states and union territories (UTs) of India. The data were analyzed using linear regression. CBR and IMR were taken as the dependent variables; while the overall literacy rates, male, and female literacy rates were the independent variables. Results: CBRs were inversely related to literacy rates (slope parameter = ?0.402, P < 0.001). On multiple linear regression with male and female literacy rates, a significant inverse relationship emerged between female literacy rate and CBR (slope = ?0.363, P < 0.001), while male literacy rate was not significantly related to CBR (P = 0.674). IMR of the states were also inversely related to their literacy rates (slope = ?1.254, P < 0.001). Multiple linear regression revealed a significant inverse relationship between IMR and female literacy (slope = ?0.816, P = 0.031), whereas male literacy rate was not significantly related (P = 0.630). Conclusion: Female literacy is relatively highly important for both population stabilization and better infant health.

  10. Saturn component failure rate and failure rate modifiers

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Failure mode frequency ratios, environmental adjustment factors, and failure rates for mechanical and electromechanical component families are presented. The failure rates and failure rate modifiers resulted from a series of studies whose purpose was to provide design, tests, reliability, and systems engineers with accurate, up-to-date failure rate information. The results of the studies were achieved through an extensive engineering analysis of the Saturn Program test data and Unsatisfactory Condition Reports (UCR's) and the application of mathematical techniques developed for the studies.

  11. cessing to determine heart rate and breathing rate.

    E-print Network

    Kastner, Marc A.

    modeled on pigs. With an almost identical gastrointestinal (GI) tract, an equivalent heart and lung size of accuracy between the datasets for both heart rate and breathing rate. (This model did not test of a material resis- tant to acid, perhaps a polycarbon- ate sheathing. "This decision will be multiple

  12. 15 CFR 700.3 - Priority ratings and rated orders.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Priority ratings and rated orders. 700.3 Section 700.3 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE NATIONAL SECURITY INDUSTRIAL...

  13. 15 CFR 700.3 - Priority ratings and rated orders.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 2 2011-01-01 2011-01-01 false Priority ratings and rated orders. 700.3 Section 700.3 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE NATIONAL SECURITY INDUSTRIAL...

  14. Nontraditional Student Graduation Rate Benchmarks

    ERIC Educational Resources Information Center

    Miller, Nathan B.

    2014-01-01

    The prominence of discourse on postsecondary degree completion, student persistence, and retention has increased in the national dialogue. Heightened attention to college completion rates by the federal government and pressure to tie state funding to performance metrics associated with graduation rates are catalysts for the discussion.…

  15. Value of IDEA Ratings Questioned

    ERIC Educational Resources Information Center

    Samuels, Christina A.

    2010-01-01

    Just as it has every June since 2006, the U.S. Department of Education last month delivered a rating to each state and territory based on the performance of its special education programs. The ratings, intended to fulfill the Individuals with Disabilities Education Act's requirement that "measurable" and "rigorous" targets be met on the 6.7…

  16. RECYCLING RATE STUDY Prepared by

    E-print Network

    Laughlin, Robert B.

    NATIONAL RECYCLING RATE STUDY Prepared by: Smith, Bucklin and Associates, Inc. Market Research and Statistics Division Chicago, Illinois July 2003 PRINTED ON RECYCLED PAPER #12;BCI RECYCLING RATE STUDY TABLE ....................................................................................................1 II. METHODOLOGY A. Total Pounds of Lead Recycled from Batteries

  17. Rate/Trend Comparison Table

    Cancer.gov

    Compares cancer rate changes between a county of a state and the entire state or between a state and the US. The graphic version of this table groups the data so you can see quickly if the trends are rising, falling, or remaining stable and how they compare to the selected comparison rates.

  18. Predicting the Divorce Rate: Down?

    ERIC Educational Resources Information Center

    Kemper, Theodore D.

    1983-01-01

    Predicted a decline in the divorce rate based on 10 factors including: decline in marriage rate, older age at marriage, mental health improvement, upper limit on employed women, less migration, end of the cultural revolution, exhaustion of latency effect of no-fault divorce, and fear of the consequences of divorce. (JAC)

  19. Towards Smart Grid Dynamic Ratings

    NASA Astrophysics Data System (ADS)

    Cheema, Jamal; Clark, Adrian; Kilimnik, Justin; Pavlovski, Chris; Redman, David; Vu, Maria

    2011-08-01

    The energy distribution industry is giving greater attention to smart grid solutions as a means for increasing the capabilities, efficiency and reliability of the electrical power network. The smart grid makes use of intelligent monitoring and control devices throughout the distribution network to report on electrical properties such as voltage, current and power, as well as raising network alarms and events. A further aspect of the smart grid embodies the dynamic rating of electrical assets of the network. This fundamentally involves a rating of the load current capacity of electrical assets including feeders, transformers and switches. The mainstream approach to rate assets is to apply the vendor plate rating, which often under utilizes assets, or in some cases over utilizes when environmental conditions reduce the effective rated capacity, potentially reducing lifetime. Using active intelligence we have developed a rating system that rates assets in real time based upon several events. This allows for a far more efficient and reliable electrical grid that is able to extend further the life and reliability of the electrical network. In this paper we describe our architecture, the observations made during development and live deployment of the solution into operation. We also illustrate how this solution blends with the smart grid by proposing a dynamic rating system for the smart grid.

  20. Evolution & the Cesarean Section Rate

    ERIC Educational Resources Information Center

    Walsh, Joseph A.

    2008-01-01

    "Nothing in biology makes sense except in the light of evolution." This was the title of an essay by geneticist Theodosius Dobzhansky writing in 1973. Many causes have been given for the increased Cesarean section rate in developed countries, but biologic evolution has not been one of them. The C-section rate will continue to rise, because the…

  1. Depression Rating Scale for Children.

    ERIC Educational Resources Information Center

    Poznanski, Elva O.; And Others

    1979-01-01

    A Children's Depression Rating Scale (CDRS) was devised and tested on 30 inpatient children (6 to 12 years old) in a medical hospital. A high correlation was found between global ratings by two psychiatrists of severity of depression and scores on the CDRS. Journal availability: American Academy of Pediatrics, P.O. Box 1034, Evanston, IL 60204.…

  2. Robust Characterization of Loss Rates

    NASA Astrophysics Data System (ADS)

    Wallman, Joel J.; Barnhill, Marie; Emerson, Joseph

    2015-08-01

    Many physical implementations of qubits—including ion traps, optical lattices and linear optics—suffer from loss. A nonzero probability of irretrievably losing a qubit can be a substantial obstacle to fault-tolerant methods of processing quantum information, requiring new techniques to safeguard against loss that introduce an additional overhead that depends upon the loss rate. Here we present a scalable and platform-independent protocol for estimating the average loss rate (averaged over all input states) resulting from an arbitrary Markovian noise process, as well as an independent estimate of detector efficiency. Moreover, we show that our protocol gives an additional constraint on estimated parameters from randomized benchmarking that improves the reliability of the estimated error rate and provides a new indicator for non-Markovian signatures in the experimental data. We also derive a bound for the state-dependent loss rate in terms of the average loss rate.

  3. Robust Characterization of Loss Rates.

    PubMed

    Wallman, Joel J; Barnhill, Marie; Emerson, Joseph

    2015-08-01

    Many physical implementations of qubits-including ion traps, optical lattices and linear optics-suffer from loss. A nonzero probability of irretrievably losing a qubit can be a substantial obstacle to fault-tolerant methods of processing quantum information, requiring new techniques to safeguard against loss that introduce an additional overhead that depends upon the loss rate. Here we present a scalable and platform-independent protocol for estimating the average loss rate (averaged over all input states) resulting from an arbitrary Markovian noise process, as well as an independent estimate of detector efficiency. Moreover, we show that our protocol gives an additional constraint on estimated parameters from randomized benchmarking that improves the reliability of the estimated error rate and provides a new indicator for non-Markovian signatures in the experimental data. We also derive a bound for the state-dependent loss rate in terms of the average loss rate. PMID:26296105

  4. Innovative Rates Program. Final report

    SciTech Connect

    Not Available

    1982-06-21

    Title II of the Energy Conservation and Production Act (ECPA) as amended by the Public Utility Regulatory Policies Act (PURPA) provided financial assistance to state utility regulatory commissions, nonregulated electric utilities, and the Tennessee Valley Authority through the Innovative Rates Program. The financial assistance was to be used to plan or carry out electric utility regulatory rate reform initiatives relating to innovative rate structures that encourage conservation of energy, electric utility efficiency and reduced costs, and equitable rates to consumers. The Federal and local objectives of the project are described. Activities planned and accomplishments are summarized for the following: project management, data collection, utility bill evaluation, billing enclosure/mailing evaluation, media program evaluation, display evaluation, rate study sessions evaluation, speakers bureau evaluation, and individual customer contacts. A timetable/milestone chart and financial information are included. (MHR)

  5. The Average of Rates and the Average Rate.

    ERIC Educational Resources Information Center

    Lindstrom, Peter

    1988-01-01

    Defines arithmetic, harmonic, and weighted harmonic means, and discusses their properties. Describes the application of these properties in problems involving fuel economy estimates and average rates of motion. Gives example problems and solutions. (CW)

  6. Interviewer's ratings of personality: can these ratings predict job performance? 

    E-print Network

    Archuleta, Kathryn Diane

    1998-01-01

    The link between personality and job performance has usually been studied using self-report personality data. The present study looked at whether an interviewer's ratings of an applicant's personality can predict future ...

  7. The Airline Quality Rating 1999

    NASA Technical Reports Server (NTRS)

    Bowen, Brent D.; Headley, Dean E.

    1999-01-01

    The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline performance on combined multiple criteria. This current report, Airline Quality Rating 1999, reflects an updated approach to calculating monthly Airline Quality Rating scores for 1998. AQR scores for the calendar year 1998 are based on 15 elements that focus on airline performance areas important to air travel consumers. The Airline Quality Rating is a summary of month-by-month quality ratings for the ten major U.S. airlines operating during 1998. Using the Airline Quality Rating system of weighted averages and monthly performance data in the areas of on-time arrivals, involuntary denied boardings, mishandled baggage, and a combination of 12 customer complaint categories, major airlines comparative performance for the calendar year 1998 is reported. This research monograph contains a brief summary of the AQR methodology, detailed data and charts that track comparative quality for major airlines domestic operations for the 12 month period of 1998, and industry average results. Also, comparative Airline Quality Rating data for 1997, using the updated criteria, are included to provide a reference point regarding quality in the industry.

  8. Deformational injection rate measuring method

    NASA Astrophysics Data System (ADS)

    Mar?i?, Milan

    2002-09-01

    After completing the diesel engine endurance testing, we detected various traces of thermal load on the walls of combustion chambers located in the engine pistons. The engines were fitted with ? combustion chambers. The thermal load of different intensity levels occurred where the spray of fuel, fuel vapor, and air interacted with the combustion chamber wall. The uneven thermal load distribution of the combustion chamber wall results from varying injection rates in each injection nozzle hole. The most widely applied controlling methods so far for injection rate measurement, such as the Zeuch and Bosch concepts, allow measurement of only the total injection rate in multihole nozzles, without providing any indication whatsoever of the injection rate differences in individual injection nozzle holes. The new deformational measuring method described in the article allows the injection rate to be measured in each hole of the multihole nozzle. The results of the measurements using this method showed that the differences occurred in injection rates of individual injection nozzle holes. These differences may be the cause of various thermal loads on the combustion chamber walls. The criterion for injection rate is the deformation of the membrane due to an increase in the fuel quantity in the measuring space and due to the pressure waves resulting from the fuel being injected into the measuring space. The membrane deformation is measured using strain gauges, glued to the membrane and forming the Wheatstone's bridge. We devoted special attention to the temperature compensation of the Wheatstone's bridge and the membrane, heated up during the measurements.

  9. The Airline Quality Rating 2004

    NASA Technical Reports Server (NTRS)

    Bowen, Brent D.; Headley, Dean E.

    2004-01-01

    The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, the Airline Quality Rating 2004, reflects monthly Airline Quality Rating scores for 2003. AQR scores far the calendar year 2003 are based on 15 elemnts in four major areas that focus on airline performance aspects important to air travel consumers. The Airline Quality Rating 2004 is a summary of month-by-month quality ratings for U.S. airlines that have at least 1% of domestic passenger volume during 2003. Using the Airline Quality Rating system of weighted averages and monthly performance data in the areas of on-time arrivals, involuntary denied boardings, mishandled baggage, and a combination of 12 customer complaint categories, airlines comparative performance for the calendar year of 2003 is reported. This research monograph contains a brief summary of the AQR methodology, detailed data and charts that track comparative quality for domestic airline operations for the 12-month period of 2003, and industry results. Also, comparative Airline Quality Rating data for 2002 are included, where available, to provide historical perspective

  10. The Airline Quality Rating 2002

    NASA Technical Reports Server (NTRS)

    Bowen, Brent D.; Headley, Dean E.

    2002-01-01

    The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, Airline Quality Rating 2002, reflects monthly Airline Quality Rating scores for 2001. AQR scores for the calendar year 2001 are based on 15 elements that focus on airline performance areas important to air travel consumers. The Airline Quality Rating 2002 is a summary of month-by-month quality ratings for the 11 largest U.S. airlines operating during 2001. Using the Airline Quality Rating system of weighted averages and monthly performance data in the areas of on-time arrivals, involuntary denied boardings, mishandled baggage, and a combination of 12 customer complaint categories, airlines comparative performance for the calendar year of 2001 is reported. This research monograph contains a brief summary of the AQR methodology, detailed data and charts that track comparative quality for domestic airline operations for the 12-month period of 2001, and industry average results. Also, comparative Airline Quality Rating data for 2000 are included for each airline to provide historical perspective regarding performance quality in the industry.

  11. The Airline Quality Rating 2001

    NASA Technical Reports Server (NTRS)

    Bowen, Brent D.; Headley, Dean E.

    2001-01-01

    The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, Airline Quality Rating 2001, reflects monthly Airline Quality Rating scores for 2000. AQR scores for the calendar year 2000 are based on 15 elements that focus on airline performance areas important to air travel consumers. The Airline Quality Rating 2001 is a summary of month-by-month quality ratings for the ten major U.S. airlines operating during 2000. Using the Airline Quality Rating system of weighted averages and monthly performance data in the areas of on-time arrivals, involuntary denied boardings, mishandled baggage, and a combination of 12 customer complaint categories, major airlines comparative performance for the calendar year of 2000 is reported. This research monograph contains a brief summary of the AQR methodology, detailed data and charts that track comparative quality for major airlines domestic operations for the 12 month period of 2000, and industry average results. Also, comparative Airline Quality Rating data for 1999 are included for each airline to provide historical perspective regarding performance quality in the industry.

  12. Orthogonal Rendezvous Routing Protocol for Wireless Mesh Networks

    E-print Network

    Cheng, Bow-Nan

    Routing in multi-hop wireless networks involves the indirection from a persistent name (or ID) to a locator. Concepts such as coordinate space embedding help reduce the number and dynamism complexity of bindings and state ...

  13. An autonomous rendezvous and docking system using cruise missile technology

    NASA Astrophysics Data System (ADS)

    Jones, Ed; Nicholson, Bruce

    In November 1990 General Dynamics demonstrated an AR&D system for members of the Strategic Avionics Technology Working Group. This simulation utilized prototype hardware derived from the Cruise Missile and Centaur avionics systems. The object of this proof of concept demonstration was to show that all the accuracy, reliability, and operational requirements established for a spacecraft to dock with Space Station Freedom could be met by the proposed AR&D system.

  14. An autonomous rendezvous and docking system using cruise missile technology

    NASA Technical Reports Server (NTRS)

    Jones, ED; Nicholson, Bruce

    1991-01-01

    In November 1990 General Dynamics demonstrated an AR&D system for members of the Strategic Avionics Technology Working Group. This simulation utilized prototype hardware derived from the Cruise Missile and Centaur avionics systems. The object of this proof of concept demonstration was to show that all the accuracy, reliability, and operational requirements established for a spacecraft to dock with Space Station Freedom could be met by the proposed AR&D system.

  15. Rendezvous with the World: Missouri Southern State University's Themed Semesters

    ERIC Educational Resources Information Center

    Stebbins, Chad

    2011-01-01

    Although most universities emphasize study abroad as the primary vehicle to internationalize the campus, in reality only a small percentage of students actually participate in this endeavor. The internationally themed semesters at Missouri Southern State University (MSSU) reach virtually every student, and provide a global perspective and cultural…

  16. Halo: Managing Node Rendezvous in Opportunistic Sensor Networks

    E-print Network

    Campbell, Andrew T.

    devices equipped with a short-range radio (e.g., ZigBee, Bluetooth, WiFi) are carried by humans or mounted of the sphere of interaction is implemented by both transmit power control, and #12;multihop signaling between and duration of the sensors' travel th

  17. Proximal tibiofibular joint: Rendezvous with a forgotten articulation.

    PubMed

    Sarma, Amitav; Borgohain, Bhaskar; Saikia, Bishwajeet

    2015-01-01

    The proximal tibiofibular joint (PTFJ) is a plane type synovial joint. The primary function of the PTFJ is dissipation of torsional stresses applied at the ankle and the lateral tibial bending moments besides a very significant tensile, rather than compressive weight bearing. Though rare, early diagnosis and treatment of the PTFJ dislocation are essential to prevent chronic joint instability and extensive surgical intervention to restore normal PTFJ biomechanics, ankle and knee function, especially in athletes prone to such injuries. PTFJ dislocations often remain undiagnosed in polytrauma scenario with ipsilateral tibial fracture due to the absence of specific signs and symptoms of PTFJ injury. Standard orthopedic textbooks generally describe no specific tests or radiological signs for assessment of the integrity of this joint. The aim of this paper was to review the relevant clinical anatomy, biomechanics and traumatic pathology of PTFJ with its effect on the knee emphasizing the importance of early diagnosis through a high index of suspicion. Dislocation of the joint may have serious implications for the knee joint stability since fibular collateral ligament and posterolateral ligament complex is attached to the upper end of the fibula. Any high energy knee injury with peroneal nerve palsy should immediately raise the suspicion of PTFJ dislocation especially if the mechanism of injury involved knee twisting in flexion beyond 80° and in such cases a comparative radiograph of the contralateral side should be performed. Wider clinical awareness can avoid both embarrassingly extensive surgeries due to diagnostic delays or unnecessary overtreatment due to misinformation on the part of the treating surgeon. PMID:26538753

  18. Orbital Express AVGS Validation and Calibration for Automated Rendezvous

    NASA Technical Reports Server (NTRS)

    Heaton, Andrew F.; Howard, Richard T.; Pinson, Robin M.

    2008-01-01

    From March to July of 2007, the DARPA Orbital Express mission achieved a number of firsts in autonomous spacecraft operations. The NASA Advanced Video Guidance Sensor (AVGS) was the primary docking sensor during the first two dockings and was used in a blended mode three other automated captures. The AVGS performance exceeded its specification by approximately an order of magnitude. One reason that the AVGS functioned so well during the mission was that the validation and calibration of the sensor prior to the mission advanced the state-of-the-art for proximity sensors. Some factors in this success were improvements in ground test equipment and truth data, the capability for ILOAD corrections for optical and other effects, and the development of a bias correction procedure. Several valuable lessons learned have applications to future proximity sensors.

  19. Orbital rendezvous using an Augmented Lambert Guidance scheme

    E-print Network

    MacLellan, Sara Jean

    2005-01-01

    The development of an Augmented Lambert Guidance Algorithm that matches the position and velocity of an orbiting target spacecraft is presented in this thesis. The Augmented Lambert Guidance Algorithm manipulates the inputs ...

  20. Laser space rendezvous and docking system trade-off study

    NASA Technical Reports Server (NTRS)

    Adelman, S.; Levinson, S.

    1975-01-01

    The use, design, and fabrication feasibility of scanning the laser beam by swiveling the outside mirror with a ball joint swivel system is examined along with the applicability of graphite reinforced epoxy material for the construction of reflective optics. It is indicated that (1) the cost of graphite-epoxy will be more than that of many other materials due to the amount of special tooling required; (2) the weight advantage of graphite-epoxy over beryllium is minimal; the ball joint swivel system is accurate enough to perform the scanning function; and that the ball joint will result in a simpler and more cost effective scanning mechanism.

  1. Frozen-anomaly transformation for the elliptic rendezvous problem

    NASA Astrophysics Data System (ADS)

    Roa, Javier; Peláez, Jesús

    2015-01-01

    A new solution to relative motion on elliptical orbits is presented, based on a novel transformation from the reference state vector to the relative state vector. The relative orbit is constructed assuming that the anomaly, and not the time, is the invariant element throughout the transformation. This concept arises naturally from the variational form of anomaly-explicit formulations. In particular, this paper explores the capabilities of a formulation developed by Peláez et al. (Celest Mech Dyn Astron. 97, 131-150, 2007), called Dromo. This formulation exploits the advantages of the ideal reference frames and quaternionic descriptions of the orbital plane. The linear variational form of the equations of motion in Dromo is developed herein, and the resulting transformation matrix is presented. When applied to the reference state vector, this linear transformation provides the relative state vector at any step. The invariance in the anomaly implies a certain time delay in the results. Physical times for leader and follower do not coincide after the transformation. To recover the sense of the solution an additional correction is applied a posteriori to cancel this intrinsic time delay. The performance of the new transformation is compared against previous solutions to the problem through a set of numerical examples. Important error reductions in determining the relative orbit are observed in these tests.

  2. Technology of H-II Transfer Vehicle Rendezvous System

    NASA Astrophysics Data System (ADS)

    Kasai, Toru; Ueda, Satoshi; Uematsu, Hirohiko

    The H-II Transfer Vehicle (HTV), which is a Japanese unmanned cargo transfer spacecraft, will deliver supplies to the International Space Station (ISS). The first HTV will be launched in 2009 from the Tanegashima Space Center aboard an H-IIB launch vehicle with up to 6,000kg of supplies. HTV approaches to the ISS and the Space Station Remote Manipulator System (SSRMS), known as Canadarm2, will grapple the HTV and berth it to the ISS. After the supplies, the HTV will then be loaded with waste materials and then separated from the ISS by SSRMS. HTV conducts departure sequence from ISS after release from SSRMS and reentry to the atmosphere. In this paper, technology of HTV automated Guidance, Navigation and Control (GN&C) system is presented.

  3. Apollo 7/S-IVB Rendezvous in space

    NASA Technical Reports Server (NTRS)

    1968-01-01

    The expended Saturn IVB stage as photographed from the Apollo 7 spacecraft during transposition and docking maneuvers at an altitude of 126 nautical miles, at ground elapsed time of three hours, 11 minutes. The round, white disc inside the open panels of the Saturn IVB is a simulated docking target similar to that used on the lunar module for docking during lunar missions. The spacecraft is directly over Odessa-Midland, Texas. The view between the two panels (area of large puffy clouds) extends southwest across Texas into the Mexican State of Chihuahua. The distance between the Apollo 7 spacecraft and the S-(VB is approximately 50 feet.

  4. Optimizing the Earth-LISA "rendez-vous"

    E-print Network

    Fabrizio De Marchi; Giuseppe Pucacco; Massimo Bassan

    2011-07-14

    We present a general survey of heliocentric LISA orbits, hoping it might help in the exercise of rescoping the mission. We try to semi-analytically optimize the orbital parameters in order to minimize the disturbances coming from the Earth-LISA interaction. In a set of numerical simulations we include nonautonomous perturbations and provide an estimate of Doppler shift and breathing as a function of the trailing angle.

  5. Randomized Rendez-Vous with Limited Memory EVANGELOS KRANAKIS

    E-print Network

    Morin, Pat

    of autonomous mobile software agents gathering in a distributed network. This is a fundamental operation useful of Computer Science, Carleton University, 1125 Colonel By Drive, Ottawa, ON, CANADA K1S 5B6. D. Krizanc provided that the copies are not made or distributed for profit or commercial advantage, the ACM copyright

  6. Consideration of radar target glint from ST during OMV rendezvous

    NASA Technical Reports Server (NTRS)

    Mcdonald, M. W.; Malone, L. B.; Gleason, E. H.

    1985-01-01

    The nature of radar target glint and the factors upon which it depends when using the Hubble Space Telescope as a radar target is discussed. An analysis of the glint problem using a 35 MHz or 94 MHz radar on the orbital maneuvering vehicle is explored. A strategy for overcoming glint is suggested.

  7. Management and Conservation Article Surveying Predicted Rendezvous Sites to

    E-print Network

    Mitchell, Mike

    . Monitoring large carnivores is notoriously difficult because they tend to be elusive, occur in low densities). Further, because many large carnivores are territorial (i.e., maintaining exclusive use of home ranges for monitoring large carnivores where funding and manpower are sufficient to collar and track a large proportion

  8. Saturn/Titan Rendezvous: A Solar-Sail Aerocapture Mission

    NASA Technical Reports Server (NTRS)

    Matloff, Gregory L.; Taylor, Travis; Powell, Conley

    2004-01-01

    A low-mass Titan orbiter is proposed that uses conservative or optimistic solar sails for all post-Earth-escape propulsion. After accelerating the probe onto a trans-Saturn trajectory, the sail is used parachute style for Saturn capture during a pass through Saturn's outer atmosphere. If the apoapsis of the Saturn-capture orbit is appropriate, the aerocapture maneuver can later be repeated at Titan so that the spacecraft becomes a satellite of Titan. An isodensity-atmosphere model is applied to screen aerocapture trajectories. Huygens/Cassini should greatly reduce uncertainties regarding the upper atmospheres of Saturn and Titan.

  9. Terminal Spacecraft Rendezvous and Capture with LASSO Model Predictive Control

    E-print Network

    Hartley, Edward N.; Gallieri, Marco; Maciejowski, Jan M.

    2013-08-20

    Mass of mars M 6.4191× 1023 kg Semimajor axis a0 3893.4× 103 m Eccentricity e0 0 – Gravitational parameter µ 4.2835× 1013 m3s?1 Orbit angular velocity ?? 8.5193× 10?4 rad s?1 Chaser mass mchs,0 1575 kg x z y Mars Target Figure 2. Visualisation... scenario based on the final capture phase of the Mars Sample Return (MSR) mission (Beaty et al. 2008, Mura 2007, Saponara et al. 2011, Hartley et al. 2012) is investigated. The linearised relative dynamics of a controller chaser spacecraft with respect to a...

  10. Orbital Maneuvers and Space Rendezvous Eugene I. Butikov

    E-print Network

    Butikov, Eugene

    , the velocity of the craft can be changed by the thrust of a rocket engine that is so oriented the water), and our intuition fails us. The orbital maneuvers are not as simple as driving a car or a motor during the thrust), the change in the orbital velocity of the spacecraft is essentially instantaneous

  11. 78 FR 73821 - Publication of Depreciation Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-09

    ...Utilities Service Publication of Depreciation Rates AGENCY: Rural Utilities Service. ACTION: Notice of Depreciation Rates for Telecommunications Plant...Telecommunications Program. RUS announces the depreciation rates for telecommunications...

  12. Blood Pressure vs. Heart Rate

    MedlinePLUS

    ... pressure. If you take your pulse (measuring your heart rate) before, during and after physical activity, you'll notice your pulse will increase over the course of the exercise. The greater the intensity and the more energy ...

  13. Confidence rating for eutrophication assessments.

    PubMed

    Brockmann, Uwe H; Topcu, Dilek H

    2014-05-15

    Confidence of monitoring data is dependent on their variability and representativeness of sampling in space and time. Whereas variability can be assessed as statistical confidence limits, representative sampling is related to equidistant sampling, considering gradients or changing rates at sampling gaps. By the proposed method both aspects are combined, resulting in balanced results for examples of total nitrogen concentrations in the German Bight/North Sea. For assessing sampling representativeness surface areas, vertical profiles and time periods are divided into regular sections for which individually the representativeness is calculated. The sums correspond to the overall representativeness of sampling in the defined area/time period. Effects of not sampled sections are estimated along parallel rows by reducing their confidence, considering their distances to next sampled sections and the interrupted gradients/changing rates. Confidence rating of time sections is based on maximum differences of sampling rates at regular time steps and related means of concentrations. PMID:24680718

  14. High compression rate text summarization

    E-print Network

    Branavan, Satchuthananthavale Rasiah Kuhan

    2008-01-01

    This thesis focuses on methods for condensing large documents into highly concise summaries, achieving compression rates on par with human writers. While the need for such summaries in the current age of information overload ...

  15. High repetition rate fiber lasers

    E-print Network

    Chen, Jian, Ph. D. Massachusetts Institute of Technology

    2009-01-01

    This thesis reports work in high repetition rate femtosecond fiber lasers. Driven by the applications including optical arbitrary waveform generation, high speed optical sampling, frequency metrology, and timing and frequency ...

  16. Rate of volcanism on Venus

    SciTech Connect

    Fegley, B. Jr.; Prinn, R.G.

    1988-07-01

    The maintenance of the global H/sub 2/SO/sub 4/ clouds on Venus requires volcanism to replenish the atmospheric SO/sub 2/ which is continually being removed from the atmosphere by reaction with calcium minerals on the surface of Venus. The first laboratory measurements of the rate of one such reaction, between SO/sub 2/ and calcite (CaCO/sub 3/) to form anhydrite (CaSO/sub 4/), are reported. If the rate of this reaction is representative of the SO/sub 2/ reaction rate at the Venus surface, then we estimate that all SO/sub 2/ in the Venus atmosphere (and thus the H/sub 2/SO/sub 4/ clouds) will be removed in 1.9 million years unless the lost SO/sub 2/ is replenished by volcanism. The required rate of volcanism ranges from about 0.4 to about 11 cu km of magma erupted per year, depending on the assumed sulfur content of the erupted material. If this material has the same composition as the Venus surface at the Venera 13, 14 and Vega 2 landing sites, then the required rate of volcanism is about 1 cu km per year. This independent geochemically estimated rate can be used to determine if either (or neither) of the two discordant (2 cu km/year vs. 200 to 300 cu km/year) geophysically estimated rates is correct. The geochemically estimated rate also suggests that Venus is less volcanically active than the Earth.

  17. Lung Cancer Rates by Race and Ethnicity

    MedlinePLUS

    ... and ethnicity. Incidence Rates by Race/Ethnicity and Sex "Incidence rate" means how many people out of ... Alaska Native). Death Rates by Race/Ethnicity and Sex From 1999–2012, the rate of people dying ...

  18. Rating scales for musician's dystonia

    PubMed Central

    Berque, Patrice; Jabusch, Hans-Christian; Altenmüller, Eckart; Frucht, Steven J.

    2013-01-01

    Musician's dystonia (MD) is a focal adult-onset dystonia most commonly involving the hand. It has much greater relative prevalence than non-musician’s focal hand dystonias, exhibits task specificity at the level of specific musical passages, and is a particularly difficult form of dystonia to treat. For most MD patients, the diagnosis confirms the end of their music performance careers. Research on treatments and pathophysiology is contingent upon measures of motor function abnormalities. In this review, we comprehensively survey the literature to identify the rating scales used in MD and the distribution of their use. We also summarize the extent to which the scales have been evaluated for their clinical utility, including reliability, validity, sensitivity, specificity to MD, and practicality for a clinical setting. Out of 135 publications, almost half (62) included no quantitative measures of motor function. The remaining 73 studies used a variety of choices from among 10 major rating scales. Most used subjective scales involving either patient or clinician ratings. Only 25% (18) of the studies used objective scales. None of the scales has been completely and rigorously evaluated for clinical utility. Whether studies involved treatments or pathophysiologic assays, there was a heterogeneous choice of rating scales used with no clear standard. As a result, the collective interpretive value of those studies is limited because the results are confounded by measurement effects. We suggest that the development and widespread adoption of a new clinically useful rating scale is critical for accelerating basic and clinical research in MD. PMID:23884039

  19. High Data Rate Quantum Cryptography

    NASA Astrophysics Data System (ADS)

    Kwiat, Paul; Christensen, Bradley; McCusker, Kevin; Kumor, Daniel; Gauthier, Daniel

    2015-05-01

    While quantum key distribution (QKD) systems are now commercially available, the data rate is a limiting factor for some desired applications (e.g., secure video transmission). Most QKD systems receive at most a single random bit per detection event, causing the data rate to be limited by the saturation of the single-photon detectors. Recent experiments have begun to explore using larger degree of freedoms, i.e., temporal or spatial qubits, to optimize the data rate. Here, we continue this exploration using entanglement in multiple degrees of freedom. That is, we use simultaneous temporal and polarization entanglement to reach up to 8.3 bits of randomness per coincident detection. Due to current technology, we are unable to fully secure the temporal degree of freedom against all possible future attacks; however, by assuming a technologically-limited eavesdropper, we are able to obtain 23.4 MB/s secure key rate across an optical table, after error reconciliation and privacy amplification. In this talk, we will describe our high-rate QKD experiment, with a short discussion on our work towards extending this system to ship-to-ship and ship-to-shore communication, aiming to secure the temporal degree of freedom and to implement a 30-km free-space link over a marine environment.

  20. HEART RATE VARIABILITY AND 24-HOUR MINIMUM HEART RATE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heart rate variability (HRV) indices based on 24-hour electrocardiograph recordings have been used in clinical research studies to assess the aggregate activity of the autonomic nervous system. While 24-hour HRV is generally considered non-invasive, use in research protocols typically involves cons...

  1. Event Rates for Binary Inspiral

    E-print Network

    V. Kalogera; K. Belczynski

    2001-01-03

    Double compact objects (neutron stars and black holes) found in binaries with small orbital separations are known to spiral in and are expected to coalesce eventually because of the emission of gravitational waves. Such inspiral and merger events are thought to be primary sources for ground based gravitational-wave interferometric detectors (such as LIGO). Here, we present a brief review of estimates of coalescence rates and we examine the origin and relative importance of uncertainties associated with the rate estimates. For the case of double neutron star systems, we compare the most recent rate estimates to upper limits derived in a number of different ways. We also discuss the implications of the formation of close binaries with two non-recycled pulsars.

  2. MEMS Rate Sensors for Space

    NASA Technical Reports Server (NTRS)

    Gambino, Joel

    2000-01-01

    Micromachined Electro Mechanical System (MEMS) Rate Sensors are an enabling technology for Nanosatellites. The recent award of a Nanosatellite program to the Goddard Space Flight Center (GSFC) underscores the urgency of the development of these systems for space use. The Guidance Navigation and Control Center (GNCC) at the GSFC is involved in several efforts to develop this technology. The GNCC seeks to improve the performance of these sensors and develop flight ready systems for spacecraft use by partnering with industry leaders in MEMS Rate Sensor development. This paper introduces Microgyros and discusses the efforts in progress at the GNCC to improve the performance of these units and develop MEMS Rate Sensors for space use.

  3. Coal Transportation Rate Sensitivity Analysis

    EIA Publications

    2005-01-01

    On December 21, 2004, the Surface Transportation Board (STB) requested that the Energy Information Administration (EIA) analyze the impact of changes in coal transportation rates on projected levels of electric power sector energy use and emissions. Specifically, the STB requested an analysis of changes in national and regional coal consumption and emissions resulting from adjustments in railroad transportation rates for Wyoming's Powder River Basin (PRB) coal using the National Energy Modeling System (NEMS). However, because NEMS operates at a relatively aggregate regional level and does not represent the costs of transporting coal over specific rail lines, this analysis reports on the impacts of interregional changes in transportation rates from those used in the Annual Energy Outlook 2005 (AEO2005) reference case.

  4. Dual physiological rate measurement instrument

    NASA Technical Reports Server (NTRS)

    Cooper, Tommy G. (inventor)

    1990-01-01

    The object of the invention is to provide an instrument for converting a physiological pulse rate into a corresponding linear output voltage. The instrument which accurately measures the rate of an unknown rectangular pulse wave over an extended range of values comprises a phase-locked loop including a phase comparator, a filtering network, and a voltage-controlled oscillator, arranged in cascade. The phase comparator has a first input responsive to the pulse wave and a second input responsive to the output signal of the voltage-controlled oscillator. The comparator provides a signal dependent on the difference in phase and frequency between the signals appearing on the first and second inputs. A high-input impedance amplifier accepts an output from the filtering network and provides an amplified output DC signal to a utilization device for providing a measurement of the rate of the pulse wave.

  5. High Data Rate Instrument Study

    NASA Technical Reports Server (NTRS)

    Schober, Wayne; Lansing, Faiza; Wilson, Keith; Webb, Evan

    1999-01-01

    The High Data Rate Instrument Study was a joint effort between the Jet Propulsion Laboratory (JPL) and the Goddard Space Flight Center (GSFC). The objectives were to assess the characteristics of future high data rate Earth observing science instruments and then to assess the feasibility of developing data processing systems and communications systems required to meet those data rates. Instruments and technology were assessed for technology readiness dates of 2000, 2003, and 2006. The highest data rate instruments are hyperspectral and synthetic aperture radar instruments which are capable of generating 3.2 Gigabits per second (Gbps) and 1.3 Gbps, respectively, with a technology readiness date of 2003. These instruments would require storage of 16.2 Terebits (Tb) of information (RF communications case of two orbits of data) or 40.5 Tb of information (optical communications case of five orbits of data) with a technology readiness date of 2003. Onboard storage capability in 2003 is estimated at 4 Tb; therefore, all the data created cannot be stored without processing or compression. Of the 4 Tb of stored data, RF communications can only send about one third of the data to the ground, while optical communications is estimated at 6.4 Tb across all three technology readiness dates of 2000, 2003, and 2006 which were used in the study. The study includes analysis of the onboard processing and communications technologies at these three dates and potential systems to meet the high data rate requirements. In the 2003 case, 7.8% of the data can be stored and downlinked by RF communications while 10% of the data can be stored and downlinked with optical communications. The study conclusion is that only 1 to 10% of the data generated by high data rate instruments will be sent to the ground from now through 2006 unless revolutionary changes in spacecraft design and operations such as intelligent data extraction are developed.

  6. Recent deformation rates on Venus

    NASA Technical Reports Server (NTRS)

    Grimm, Robert E.

    1994-01-01

    Constraints on the recent geological evolution of Venus may be provided by quantitative estimates of the rates of the principal resurfacing processes, volcanism and tectonism. This paper focuses on the latter, using impact craters as strain indicators. The total postimpact tectonic strain lies in the range 0.5-6.5%, which defines a recent mean strain rate of 10(exp -18)-10(exp -17)/s when divided by the mean surface age. Interpretation of the cratering record as one of pure production requires a decline in resurfacing rates at about 500 Ma (catastrophic resurfacing model). If distributed tectonic resurfacing contributed strongly before that time, as suggested by the widespread occurrence of tessera as inliers, the mean global strain rate must have been at least approximately 10(exp -15)/s, which is also typical of terrestrial active margins. Numerical calculations of the response of the lithosphere to inferred mantle convective forces were performed to test the hypothesis that a decrease in surface strain rate by at least two orders of magnitude could be caused by a steady decline in heat flow over the last billion years. Parameterized convection models predict that the mean global thermal gradient decreases by only about 5 K/km over this time; even with the exponential dependence of viscosity upon temperature, the surface strain rate drops by little more than one order of magnitude. Strongly unsteady cooling and very low thermal gradients today are necessary to satisfy the catastrophic model. An alternative, uniformitarian resurfacing hypothesis holds that Venus is resurfaced in quasi-random 'patches' several hundred kilometers in size that occur in response to changing mantle convection patterns.

  7. Direct estimation of decoherence rates

    E-print Network

    Vladimír Bužek; Peter Rapcan; Jochen Rau; Mario Ziman

    2012-07-30

    The decoherence rate is a nonlinear channel parameter that describes quantitatively the decay of the off-diagonal elements of a density operator in the decoherence basis. We address the question of how to experimentally access such a nonlinear parameter directly without the need of complete process tomography. In particular, we design a simple experiment working with two copies of the channel, in which the registered mean value of a two-valued measurement directly determines the value of the average decoherence rate. No prior knowledge of the decoherence basis is required.

  8. 1993 Wholesale Power and Transmission Rate Schedules.

    SciTech Connect

    US Bonneville Power Administration

    1993-10-01

    Bonneville Power Administration 1993 Wholesale Power Rate Schedules and General Rate Schedule Provisions and 1993 Transmission Rate Schedules and General Transmission Rate Schedule Provisions, contained herein, were approved on an interim basis effective October 1, 1993. These rate schedules and provisions were approved by the Federal Energy Commission, United States Department of Energy, in September, 1993. These rate schedules and provisions supersede the Administration`s Wholesale Power Rate Schedules and General Rate Schedule Provisions and Transmission Rate Schedules and General Transmission Rate Schedule Provisions effective October 1, 1991.

  9. ORAL PRESENTATION ABSTRACT Design of an Arterial Blood Pressure, Heart Rate Variability and Breathing Rate Measuring

    E-print Network

    Haykin, Simon

    ORAL PRESENTATION ABSTRACT Design of an Arterial Blood Pressure, Heart Rate Variability can be used to calculate the instantaneous heart rate and consequently the heart rate variability blood pressure, brachial artery, breathing rate, heart rate variability, photodiode

  10. 78 FR 15973 - Fee Rate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-13

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR National Indian Gaming Commission Fee Rate Correction In notice document 2013-05334, appearing on page 14821 in the issue of Thursday, March 7, 2013, make the following correction: On page 14821, in...

  11. Columbus Payloads Flow Rate Anomalies

    NASA Technical Reports Server (NTRS)

    Quaranta, Albino; Bufano, Gaetana; DePalo, Savino; Holt, James M.; Szigetvari, Zoltan; Palumberi, Sergio; Hinderer, S.

    2011-01-01

    The Columbus Active Thermal Control System (ATCS) is the main thermal bus for the pressurized racks working inside the European laboratory. One of the ATCS goals is to provide proper water flow rate to each payload (P/L) by controlling actively the pressure drop across the common plenum distribution piping. Overall flow measurement performed by the Water Pump Assembly (WPA) is the only flow rate monitor available at system level and is not part of the feedback control system. At rack activation the flow rate provided by the system is derived on ground by computing the WPA flow increase. With this approach, several anomalies were raised during these 3 years on-orbit, with the indication of low flow rate conditions on the European racks FSL, BioLab, EDR and EPM. This paper reviews the system and P/Ls calibration approach, the anomalies occurred, the engineering evaluation on the measurement approach and the accuracy improvements proposed, the on-orbit test under evaluation with NASA and finally discusses possible short and long term solutions in case of anomaly confirmation.

  12. NASA Human-Rating Requirements

    NASA Technical Reports Server (NTRS)

    Groen, Frank; Harkins, Wil; Stamatelatos, Michael

    2010-01-01

    NASA's Procedural Requirements 87052B defines the Human-Rating Certification process and related technical requirements for human spaceflight programs developed by and for NASA. The document specifies Agency-level responsibilities related to the certification, processes to be established by the program, and technical requirements.

  13. Frame Rate and Human Vision

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.

    2012-01-01

    To enhance the quality of the theatre experience, the film industry is interested in achieving higher frame rates for capture and display. In this talk I will describe the basic spatio-temporal sensitivities of human vision, and how they respond to the time sequence of static images that is fundamental to cinematic presentation.

  14. Exchange Rates and Old People.

    ERIC Educational Resources Information Center

    Dowd, James J.

    1980-01-01

    Extends earlier work on aging as a process of exchange by focusing on the issue of exchange rates and how they are negotiated. Access to power resources declines with age, placing the old person in the position of negotiating from weakness. (Author)

  15. Cohort Default Rates in Context

    ERIC Educational Resources Information Center

    Looney, Shannon M.

    2011-01-01

    Burgeoning student loan debt indicates problems not only for the country's borrowers but also for the postsecondary system. The rise in student loan defaults signifies a rise in institutional cohort default rates (CDRs)--a measure of accountability that informs the government and the general public how well an institution prepares its students for…

  16. Prints and Posters Hourly Rate

    E-print Network

    Prints and Posters Hourly Rate Graphics and Photography: $90.00/hr Title Banners up to 12"x44" priced as posters above Poster Mailing Tubes 42" or 48", heavy duty $2.00 Color Laser Prints by Xerox 8 community. Our various services include preparation of figures for journal and grant submissions, posters

  17. Fast repetition rate (FRR) flasher

    DOEpatents

    Kolber, Zbigniew (Shoreham, NY); Falkowski, Paul (Stony Brook, NY)

    1997-02-11

    A fast repetition rate (FRR) flasher suitable for high flash photolysis including kinetic chemical and biological analysis. The flasher includes a power supply, a discharge capacitor operably connected to be charged by the power supply, and a flash lamp for producing a series of flashes in response to discharge of the discharge capacitor. A triggering circuit operably connected to the flash lamp initially ionizes the flash lamp. A current switch is operably connected between the flash lamp and the discharge capacitor. The current switch has at least one insulated gate bipolar transistor for switching current that is operable to initiate a controllable discharge of the discharge capacitor through the flash lamp. Control means connected to the current switch for controlling the rate of discharge of the discharge capacitor thereby to effectively keep the flash lamp in an ionized state between Successive discharges of the discharge capacitor. Advantageously, the control means is operable to discharge the discharge capacitor at a rate greater than 10,000 Hz and even up to a rate greater than about 250,000 Hz.

  18. Fast repetition rate (FRR) flasher

    DOEpatents

    Kolber, Z.; Falkowski, P.

    1997-02-11

    A fast repetition rate (FRR) flasher is described suitable for high flash photolysis including kinetic chemical and biological analysis. The flasher includes a power supply, a discharge capacitor operably connected to be charged by the power supply, and a flash lamp for producing a series of flashes in response to discharge of the discharge capacitor. A triggering circuit operably connected to the flash lamp initially ionizes the flash lamp. A current switch is operably connected between the flash lamp and the discharge capacitor. The current switch has at least one insulated gate bipolar transistor for switching current that is operable to initiate a controllable discharge of the discharge capacitor through the flash lamp. Control means connected to the current switch for controlling the rate of discharge of the discharge capacitor thereby to effectively keep the flash lamp in an ionized state between successive discharges of the discharge capacitor. Advantageously, the control means is operable to discharge the discharge capacitor at a rate greater than 10,000 Hz and even up to a rate greater than about 250,000 Hz. 14 figs.

  19. Commensurate Ratings of Health Care.

    ERIC Educational Resources Information Center

    Bectel, Gordon G.

    2001-01-01

    Proposes a new descriptive item statistic, the mean cumulative logit, for scoring ratings of health care at the population level. Demonstrates the advantages of the method using data from the Consumer Assessment of Health Plans Study and shows that the perceived quality of health care is greater for fee-for-service plans than managed care plans in…

  20. PBXN-110 Burn Rate Estimate

    SciTech Connect

    Glascoe, E

    2008-08-11

    It is estimated that PBXN-110 will burn laminarly with a burn function of B = (0.6-1.3)*P{sup 1.0} (B is the burn rate in mm/s and P is pressure in MPa). This paper provides a brief discussion of how this burn behavior was estimated.