Circolo enogastronomico "Della Rovere" = The Della Rovere Club

Index Scriptorium Estoniae

2012-01-01

Della Rovere Klubist, mis on Itaalia Önogastronoomiliste Ühenduste Föderatsiooni ja Euroopa Önogastronoomia Vennaskondade Nõukogu liige ja mille missiooniks on kohalike traditsioonide säilitamine, erinevate toiduainete omaduste tutvustamine, veinikultuuri õpetamine jne

Rover deployment system for lunar landing mission

Science.gov (United States)

Sutoh, Masataku; Hoshino, Takeshi; Wakabayashi, Sachiko

2017-09-01

For lunar surface exploration, a deployment system is necessary to allow a rover to leave the lander. The system should be as lightweight as possible and stored retracted when launched. In this paper, two types of retractable deployment systems for lunar landing missions, telescopic- and fold-type ramps, are discussed. In the telescopic-type system, a ramp is stored with the sections overlapping and slides out during deployment. In the fold-type system, it is stored folded and unfolds for the deployment. For the development of these ramps, a design concept study and structural analysis were conducted first. Subsequently, ramp deployment and rover release tests were performed using the developed ramp prototypes. Through these tests, the validity of their design concepts and functions have been confirmed. In the rover release test, it was observed that the developed lightweight ramp was sufficiently strong for a 50-kg rover to descend. This result suggests that this ramp system is suitable for the deployment of a 300-kg-class rover on the Moon, where the gravity is about one-sixth that on Earth. The lightweight and sturdy ramp developed in this study will contribute to both safe rover deployment and increase of lander/rover payload.

Bringing Terramechanics to bear on Planetary Rover Design

Science.gov (United States)

Richter, L.

2007-08-01

Thus far, planetary rovers have been successfully operated on the Earth's moon and on Mars. In particular, the two NASA Mars Exploration Rovers (MERs) ,Spirit' and ,Opportunity' are still in sustained daily operations at two sites on Mars more than 3 years after landing there. Currently, several new planetary rover missions are in development targeting Mars (the US Mars Science Lab vehicle for launch in 2009 and ESA's ExoMars rover for launch in 2013), with lunar rover missions under study by China and Japan for launches around 2012. Moreover, the US Constellation program is preparing pre-development of lunar rovers for initially unmanned and, subsequently, human missions to the Moon with a corresponding team dedicated to mobility system development having been set up at the NASA Glenn Research Center. Given this dynamic environment, it was found timely to establish an expert group on off-the-road mobility as relevant for robotic vehicles that would involve individuals representing the various on-going efforts on the different continents. This was realized through the International Society of Terrain-Vehicle Systems (ISTVS), a research organisation devoted to terramechanics and to the ,science' of off-the-road vehicle development which as a result is just now establishing a Technical Group on Terrestrial and Planetary Rovers. Members represent space-related as well as military research institutes and universities from the US, Germany, Italy, and Japan. The group's charter for 2007 is to define its objectives, functions, organizational structure and recommended research objectives to support planetary rover design and development. Expected areas of activity of the ISTVS-sponsored group include: the problem of terrain specification for planetary rovers; identification of limitations in modelling of rover mobility; a survey of existing rover mobility testbeds; the consolidation of mobility predictive models and their state of validation; sensing and real

Cerebellum Augmented Rover Development

Science.gov (United States)

King, Matthew

2005-01-01

Bio-Inspired Technologies and Systems (BITS) are a very natural result of thinking about Nature's way of solving problems. Knowledge of animal behaviors an be used in developing robotic behaviors intended for planetary exploration. This is the expertise of the JFL BITS Group and has served as a philosophical model for NMSU RioRobolab. Navigation is a vital function for any autonomous system. Systems must have the ability to determine a safe path between their current location and some target location. The MER mission, as well as other JPL rover missions, uses a method known as dead-reckoning to determine position information. Dead-reckoning uses wheel encoders to sense the wheel's rotation. In a sandy environment such as Mars, this method is highly inaccurate because the wheels will slip in the sand. Improving positioning error will allow the speed of an autonomous navigating rover to be greatly increased. Therefore, local navigation based upon landmark tracking is desirable in planetary exploration. The BITS Group is developing navigation technology based upon landmark tracking. Integration of the current rover architecture with a cerebellar neural network tracking algorithm will demonstrate that this approach to navigation is feasible and should be implemented in future rover and spacecraft missions.

International testing of a Mars rover prototype

Science.gov (United States)

Kemurjian, Alexsandr Leonovich; Linkin, V.; Friedman, L.

1993-03-01

Tests on a prototype engineering model of the Russian Mars 96 Rover were conducted by an international team in and near Death Valley in the United States in late May, 1992. These tests were part of a comprehensive design and testing program initiated by the three Russian groups responsible for the rover development. The specific objectives of the May tests were: (1) evaluate rover performance over different Mars-like terrains; (2) evaluate state-of-the-art teleoperation and autonomy development for Mars rover command, control and navigation; and (3) organize an international team to contribute expertise and capability on the rover development for the flight project. The range and performance that can be planned for the Mars mission is dependent on the degree of autonomy that will be possible to implement on the mission. Current plans are for limited autonomy, with Earth-based teleoperation for the nominal navigation system. Several types of television systems are being investigated for inclusion in the navigation system including panoramic camera, stereo, and framing cameras. The tests used each of these in teleoperation experiments. Experiments were included to consider use of such TV data in autonomy algorithms. Image processing and some aspects of closed-loop control software were also tested. A micro-rover was tested to help consider the value of such a device as a payload supplement to the main rover. The concept is for the micro-rover to serve like a mobile hand, with its own sensors including a television camera.

Using Planning, Scheduling and Execution for Autonomous Mars Rover Operations

Science.gov (United States)

Estlin, Tara A.; Gaines, Daniel M.; Chouinard, Caroline M.; Fisher, Forest W.; Castano, Rebecca; Judd, Michele J.; Nesnas, Issa A.

2006-01-01

With each new rover mission to Mars, rovers are traveling significantly longer distances. This distance increase raises not only the opportunities for science data collection, but also amplifies the amount of environment and rover state uncertainty that must be handled in rover operations. This paper describes how planning, scheduling and execution techniques can be used onboard a rover to autonomously generate and execute rover activities and in particular to handle new science opportunities that have been identified dynamically. We also discuss some of the particular challenges we face in supporting autonomous rover decision-making. These include interaction with rover navigation and path-planning software and handling large amounts of uncertainty in state and resource estimations. Finally, we describe our experiences in testing this work using several Mars rover prototypes in a realistic environment.

Acquisition of Skill Proficiency Over Multiple Sessions of a Novel Rover Simulation

Science.gov (United States)

Dean, S. L.; DeDios,Y. E.; MacDougall, H. G.; Moore, S. T.; Wood, S. J.

2011-01-01

Following long-duration exploration transits, adaptive changes in sensorimotor function may impair the crew's ability to safely perform manual control tasks such as operating pressurized rovers. Postflight performance will also be influenced by the level of preflight skill proficiency they have attained. The purpose of this study was to characterize the acquisition of skills in a motion-based rover simulation over multiple sessions, and to investigate the effects of varying the simulation scenarios. METHODS: Twenty healthy subjects were tested in 5 sessions, with 1-3 days between sessions. Each session consisted of a serial presentation of 8 discrete tasks to be completed as quickly and accurately as possible. Each task consisted of 1) perspective-taking, using a map that defined a docking target, 2) navigation toward the target around a Martian outpost, and 3) docking a side hatch of the rover to a visually guided target. The simulator utilized a Stewart-type motion base (CKAS, Australia), single-seat cabin with triple scene projection covering 150 deg horizontal by 50 deg vertical, and joystick controller. Subjects were randomly assigned to a control group (tasks identical in the first 4 sessions) or a varied-practice group. The dependent variables for each task included accuracy toward the target and time to completion. RESULTS: The greatest improvements in time to completion occurred during the docking phase. The varied-practice group showed more improvement in perspective-taking accuracy. Perspective-taking accuracy was also affected by the relative orientation of the rover to the docking target. Skill acquisition was correlated with self-ratings of previous gaming experience. DISCUSSION: Varying task selection and difficulty will optimize the preflight acquisition of skills when performing novel operational tasks. Simulation of operational manual control will provide functionally relevant evidence regarding the impact of sensorimotor adaptation on early

Exomars 2018 Rover Pasteur Payload

Science.gov (United States)

Debus, Andre; Bacher, M.; Ball, A.; Barcos, O.; Bethge, B.; Gaubert, F.; Haldemann, A.; Lindner, R.; Pacros, A.; Trautner, R.; Vag, J.

ars programme is a joint ESA-NASA program having exobiology as one of the key science objectives. It is divided into 2 missions: the first mission is ESA-led with an ESA orbiter and an ESA Entry, Descent and Landing (EDL) demonstrator, launched in 2016 by NASA, and the second mission is NASA-led, launched in 2018 by NASA carrying an ESA rover and a NASA rover both deployed by a single NASA EDL system. For ESA, the ExoMars programme will demonstrate key flight and in situ enabling technologies in support of the European ambitions for future exploration missions, as outlined in the Aurora Declaration. While the ExoMars 2016 mission will accomplish a technological objective (Entry, Descent and Landing of a payload on the surface) and a Scientific objective (investigation of Martian atmospheric trace gases and their sources, focussing particularly on methane), the ExoMars 2018 ESA Rover will carry a comprehensive and coherent suite of analytical instruments dedicated to exobiology and geology research: the Pasteur Payload (PPL). This payload includes a selection of complementary instruments, having the following goals: to search for signs of past and present life on Mars and to investigate the water/geochemical environment as a function of depth in the shallow subsurface. The ExoMars Rover includes a drill for accessing underground materials, and a Sample Preparation and Distribution System. The Rover will travel several kilometres looking for sites warranting further investigation, where it will collect and analyse samples from within outcrops and from the subsurface for traces of complex organic molecules. In addition to further details on this Exomars 2018 rover mission, this presentation will focus on the scientific objectives and the instruments needed to achieve them, including details of how the Pasteur Payload as a whole addresses Mars research objectives.

Rover waste assay system

International Nuclear Information System (INIS)

Akers, D.W.; Stoots, C.M.; Kraft, N.C.; Marts, D.J.

1997-01-01

The Rover Waste Assay System (RWAS) is a nondestructive assay system designed for the rapid assay of highly-enriched 235 U contaminated piping, tank sections, and debris from the Rover nuclear rocket fuel processing facility at the Idaho Chemical Processing Plant. A scanning system translates a NaI(Tl) detector/collimator system over the structural components where both relative and calibrated measurements for 137 Cs are made. Uranium-235 concentrations are in operation and is sufficiently automated that most functions are performed by the computer system. These functions include system calibration, problem identification, collimator control, data analysis, and reporting. Calibration of the system was done through a combination of measurements on calibration standards and benchmarked modeling. A description of the system is presented along with the methods and uncertainties associated with the calibration and analysis of the system for components from the Rover facility. 4 refs., 2 figs., 4 tabs

Development of Disk Rover, wall-climbing robot using permanent magnet disk

International Nuclear Information System (INIS)

Hirose, Shigeo; Tsutsumitake; Hiroshi; Toyama, Ryousei; Kobayashi, Kengo.

1992-01-01

A new type of wall climbing robot, named Disk Rover, using permanent magnet disks are developed. The newly introduced permanent magnet disk is to rotate the magnet disk on the surface of wall with partly contacted posture. It allows to produce high magnetic attraction force compared with conventional permanent wheel which utilizes only a small portion of the magnet installed around the wheel. The optimum design of the magnetic wheel is done by using finit element method and it is shown that the magnetic attraction force vs. weight ratio can be designed about three times higher than conventional type magnet wheel. The developed Disk Rover is 25 kg in weight including controller and battery, about 685 mm in diameter, 239 mm in height and has a pair of permanent magnet disks. It is demonstrated by the experiments that the Disk Rover can move around on the surface of the wall quite smoothly by radio control and has payload of about its own weight. Several considerations are also done in order to surmount bead weld. (author)

Rover waste assay system

Energy Technology Data Exchange (ETDEWEB)

Akers, D.W.; Stoots, C.M.; Kraft, N.C.; Marts, D.J. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

1997-11-01

The Rover Waste Assay System (RWAS) is a nondestructive assay system designed for the rapid assay of highly-enriched {sup 235}U contaminated piping, tank sections, and debris from the Rover nuclear rocket fuel processing facility at the Idaho Chemical Processing Plant. A scanning system translates a NaI(Tl) detector/collimator system over the structural components where both relative and calibrated measurements for {sup 137}Cs are made. Uranium-235 concentrations are in operation and is sufficiently automated that most functions are performed by the computer system. These functions include system calibration, problem identification, collimator control, data analysis, and reporting. Calibration of the system was done through a combination of measurements on calibration standards and benchmarked modeling. A description of the system is presented along with the methods and uncertainties associated with the calibration and analysis of the system for components from the Rover facility. 4 refs., 2 figs., 4 tabs.

Mars rover local navigation and hazard avoidance

Science.gov (United States)

Wilcox, B. H.; Gennery, D. B.; Mishkin, A. H.

1989-01-01

A Mars rover sample return mission has been proposed for the late 1990's. Due to the long speed-of-light delays between earth and Mars, some autonomy on the rover is highly desirable. JPL has been conducting research in two possible modes of rover operation, Computer-Aided Remote Driving and Semiautonomous Navigation. A recently-completed research program used a half-scale testbed vehicle to explore several of the concepts in semiautonomous navigation. A new, full-scale vehicle with all computational and power resources on-board will be used in the coming year to demonstrate relatively fast semiautonomous navigation. The computational and power requirements for Mars rover local navigation and hazard avoidance are discussed.

Scout Rover Applications for Forward Acquisition of Soil and Terrain Data

Science.gov (United States)

Sonsalla, R.; Ahmed, M.; Fritsche, M.; Akpo, J.; Voegele, T.

2014-04-01

As opposed to the present mars exploration missions future mission concepts ask for a fast and safe traverse through vast and varied expanses of terrain. As seen during the Mars Exploration Rover (MER) mission the rovers suffered a lack of detailed soil and terrain information which caused Spirit to get permanently stuck in soft soil. The goal of the FASTER1 EU-FP7 project is to improve the mission safety and the effective traverse speed for planetary rover exploration by determining the traversability of the terrain and lowering the risk to enter hazardous areas. To achieve these goals, a scout rover will be used for soil and terrain sensing ahead of the main rover. This paper describes a highly mobile, and versatile micro scout rover that is used for soil and terrain sensing and is able to co-operate with a primary rover as part of the FASTER approach. The general reference mission idea and concept is addressed within this paper along with top-level requirements derived from the proposed ESA/NASA Mars Sample Return mission (MSR) [4]. Following the mission concept and requirements [3], a concept study for scout rover design and operations has been performed [5]. Based on this study the baseline for the Coyote II rover was designed and built as shown in Figure 1. Coyote II is equipped with a novel locomotion concept, providing high all terrain mobility and allowing to perform side-to-side steering maneuvers which reduce the soil disturbance as compared to common skid steering [6]. The rover serves as test platform for various scout rover application tests ranging from locomotion testing to dual rover operations. From the lessons learned from Coyote II and for an enhanced design, a second generation rover (namely Coyote III) as shown in Figure 2 is being built. This rover serves as scout rover platform for the envisaged FASTER proof of concept field trials. The rover design is based on the test results gained by the Coyote II trials. Coyote III is equipped with two

Hybrid Aerial/Rover Vehicle

Science.gov (United States)

Bachelder, Aaron

2003-01-01

A proposed instrumented robotic vehicle called an "aerover" would fly, roll along the ground, and/or float on bodies of liquid, as needed. The aerover would combine features of an aerobot (a robotic lighter-than-air balloon) and a wheeled robot of the "rover" class. An aerover would also look very much like a variant of the "beach-ball" rovers. Although the aerover was conceived for use in scientific exploration of Titan (the largest moon of the planet Saturn), the aerover concept could readily be adapted to similar uses on Earth.

Positive-Buoyancy Rover for Under Ice Mobility

Science.gov (United States)

Leichty, John M.; Klesh, Andrew T.; Berisford, Daniel F.; Matthews, Jaret B.; Hand, Kevin P.

2013-01-01

A buoyant rover has been developed to traverse the underside of ice-covered lakes and seas. The rover operates at the ice/water interface and permits direct observation and measurement of processes affecting freeze- over and thaw events in lake and marine environments. Operating along the 2- D ice-water interface simplifies many aspects of underwater exploration, especially when compared to submersibles, which have difficulty in station-keeping and precision mobility. The buoyant rover consists of an all aluminum body with two aluminum sawtooth wheels. The two independent body segments are sandwiched between four actuators that permit isolation of wheel movement from movement of the central tether spool. For normal operations, the wheels move while the tether spool feeds out line and the cameras on each segment maintain a user-controlled fixed position. Typically one camera targets the ice/water interface and one camera looks down to the lake floor to identify seep sources. Each wheel can be operated independently for precision turning and adjustments. The rover is controlled by a touch- tablet interface and wireless goggles enable real-time viewing of video streamed from the rover cameras. The buoyant rover was successfully deployed and tested during an October 2012 field campaign to investigate methane trapped in ice in lakes along the North Slope of Alaska.

Multi-rover navigation on the lunar surface

Science.gov (United States)

Dabrowski, Borys; Banaszkiewicz, Marek

2008-07-01

The paper presents a method of determination an accurate position of a target (rover, immobile sensor, astronaut) on surface of the Moon or other celestial body devoid of navigation infrastructure (like Global Positioning System), by using a group of self-calibrating rovers, which serves as mobile reference points. The rovers are equipped with low-precision clocks synchronized by external broadcasting signal, to measure the moments of receiving radio signals sent by localized target. Based on the registered times, distances between transmitter and receivers installed on beacons are calculated. Each rover determines and corrects its own absolute position and orientation by using odometry navigation and measurements of relative distances and angles to other mobile reference points. Accuracy of navigation has been improved by the use of a calibration algorithm based on the extended Kalman filter, which uses internal encoder readings as inputs and relative measurements of distances and orientations between beacons as feedback information. The key idea in obtaining reliable values of absolute position and orientation of beacons is to first calibrate one of the rovers, using the remaining ones as reference points and then allow the whole group to move together and calibrate all the rovers in-motion. We consider a number of cases, in which basic modeling parameters such as terrain roughness, formation size and shape as well as availability of distance and angle measurements are varied.

Martian Surface Mineralogy from Rovers with Spirit, Opportunity, and Curiosity

Science.gov (United States)

Morris, Richard V.

2016-01-01

Beginning in 2004, NASA has landed three well-instrumented rovers on the equatorial martian surface. The Spirit rover landed in Gusev crater in early January, 2004, and the Opportunity rover landed on the opposite side of Mars at Meridian Planum 21 days later. The Curiosity rover landed in Gale crater to the west of Gusev crater in August, 2012. Both Opportunity and Curiosity are currently operational. The twin rovers Spirit and Opportunity carried Mossbauer spectrometers to determine the oxidation state of iron and its mineralogical composition. The Curiosity rover has an X-ray diffraction instrument for identification and quantification of crystalline materials including clay minerals. Instrument suites on all three rovers are capable of distinguishing primary rock-forming minerals like olivine, pyroxene and magnetite and products of aqueous alteration in including amorphous iron oxides, hematite, goethite, sulfates, and clay minerals. The oxidation state of iron ranges from that typical for unweathered rocks and soils to nearly completely oxidized (weathered) rocks and soils as products of aqueous and acid-sulfate alteration. The in situ rover mineralogy also serves as ground-truth for orbital observations, and orbital mineralogical inferences are used for evaluating and planning rover exploration.

Night Rover Challenge

Data.gov (United States)

National Aeronautics and Space Administration — The objective of the Night Rover Challenge was to foster innovations in energy storage technology. Specifically, this challenge asked competitors to create an energy...

CRAFT: Collaborative Rover and Astronauts Future Technology

Science.gov (United States)

Da-Poian, V. D. P.; Koryanov, V. V. K.

2018-02-01

Our project is focusing on the relationship between astronauts and rovers to best work together during surface explorations. Robots will help and assist astronauts, and will also work autonomously. Our project is to develop this type of rover.

Major accomplishments of America's nuclear rocket program (ROVER)

International Nuclear Information System (INIS)

Finseth, J.L.

1991-01-01

The United States embarked on a program to develop nuclear rocket engines in 1955. This program was known as project Rover. Initially nuclear rockets were considered as a potential backup for intercontinental ballistic missile propulsion but later proposed applications included both a lunar second stage as well as use in manned-Mars flights. Under the Rover program, 19 different reactors were built and tested during the period of 1959-1969. Additionally, several cold flow (non-fuelled) reactors were tested as well as a nuclear fuels test cell. The Rover program was terminated in 1973, due to budget constraints and an evolving political climate. The Rover program would have led to the development of a flight engine had the program continued through a logical continuation. The Rover program was responsible for a number of technological achievements. The successful operation of nuclear rocket engines on a system level represents the pinnacle of accomplishment. This paper will discuss the engine test program as well as several subsystems

Automated Planning and Scheduling for Planetary Rover Distributed Operations

Science.gov (United States)

Backes, Paul G.; Rabideau, Gregg; Tso, Kam S.; Chien, Steve

1999-01-01

Automated planning and Scheduling, including automated path planning, has been integrated with an Internet-based distributed operations system for planetary rover operations. The resulting prototype system enables faster generation of valid rover command sequences by a distributed planetary rover operations team. The Web Interface for Telescience (WITS) provides Internet-based distributed collaboration, the Automated Scheduling and Planning Environment (ASPEN) provides automated planning and scheduling, and an automated path planner provided path planning. The system was demonstrated on the Rocky 7 research rover at JPL.

Using Multi-Core Systems for Rover Autonomy

Science.gov (United States)

Clement, Brad; Estlin, Tara; Bornstein, Benjamin; Springer, Paul; Anderson, Robert C.

2010-01-01

Task Objectives are: (1) Develop and demonstrate key capabilities for rover long-range science operations using multi-core computing, (a) Adapt three rover technologies to execute on SOA multi-core processor (b) Illustrate performance improvements achieved (c) Demonstrate adapted capabilities with rover hardware, (2) Targeting three high-level autonomy technologies (a) Two for onboard data analysis (b) One for onboard command sequencing/planning, (3) Technologies identified as enabling for future missions, (4)Benefits will be measured along several metrics: (a) Execution time / Power requirements (b) Number of data products processed per unit time (c) Solution quality

NASA Mars 2020 Rover Mission: New Frontiers in Science

Science.gov (United States)

Calle, Carlos I.

2014-01-01

The Mars 2020 rover mission is the next step in NASAs robotic exploration of the red planet. The rover, based on the Mars Science Laboratory Curiosity rover now on Mars, will address key questions about the potential for life on Mars. The mission would also provide opportunities to gather knowledge and demonstrate technologies that address the challenges of future human expeditions to Mars.Like the Mars Science Laboratory rover, which has been exploring Mars since 2012, the Mars 2020 spacecraft will use a guided entry, descent, and landing system which includes a parachute, descent vehicle, and, during the provides the ability to land a very large, heavy rover on the surface of Mars in a more precise landing area. The Mars 2020 mission is designed to accomplish several high-priority planetary science goals and will be an important step toward meeting NASAs challenge to send humans to Mars in the 2030s. The mission will conduct geological assessments of the rover's landing site, determine the habitability of the environment, search for signs of ancient Martian life, and assess natural resources and hazards for future human explorers. The science instruments aboard the rover also will enable scientists to identify and select a collection of rock and soil samples that will be stored for potential return to Earth in the future. The rover also may help designers of a human expedition understand the hazards posed by Martian dust and demonstrate how to collect carbon dioxide from the atmosphere, which could be a valuable resource for producing oxygen and rocket fuel.

The Athena Mars Rover Science Payload

Science.gov (United States)

Squyes, S. W.; Arvidson, R.; Bell, J. F., III; Carr, M.; Christensen, P.; DesMarais, D.; Economou, T.; Gorevan, S.; Klingelhoefer, G.; Haskin, L.

1998-01-01

APXS will have a revised mechanical design that will cut down significantly on backscattering of alpha particles from martian atmospheric carbon. It will also include a target of known elemental composition that will be used for calibration purposes. The Athena Mossbauer Spectrometer is a diagnostic instrument for the mineralogy and oxidation state of Fe-bearing phases, which are particularly important on Mars. The instrument measures the resonant absorption of gamma rays produced by a Co-57 source to determine splitting of nuclear energy levels in Fe atoms that is related to the electronic environment surrounding them. It has been under development for space flight for many years at the Technical University of Darmstadt. The Mossbauer Spectrometer (and the other arm instruments) will be able to view a small permanent magnet array that will attract magnetic particles in the martian soil. The payload may also include a Raman Spectrometer. If included, the Raman Spectrometer will provide precise identification of major and minor mineral phases. It requires no sample preparation, and is also sensitive to organics. Fine-Scale Texture: The Instrument Arm a also carries a Microscopic Imager that will obtain high-resolution monochromatic images of the same materials for which compositional data will be obtained. Its spatial resolution is 20 micron/pixel over a 1 cm depth of field, and 40 micron/pixel over a 1-cm depth of field. Like Pancam, it uses the same active pixel sensor detectors and electronics as the rover's navigation cameras. The Instrument Arm is a three degree-of-freedom arm that uses designs and components from the Mars Pathfinder and Mars Surveyor '98 projects. Its primary function is instrument positioning. Along with the instruments noted above, it also carries a brush that can be used to remove dust and other loose coatings from rocks. Sample Collection and Storage: Martian rock and soil samples will be collected using a low-power rotary coring drill called

Recent Accomplishments in Mars Exploration: The Rover Perspective

Science.gov (United States)

McLennan, S. M.; McSween, H. Y.

2018-04-01

Mobile rovers have revolutionized our understanding of Mars geology by identifying habitable environments and addressing critical questions related to Mars science. Both the advances and limitations of rovers set the scene for Mars Sample Return.

Curiosity rover LEGO® version could land soon

Science.gov (United States)

Showstack, Randy

2012-09-01

Now that NASA's Curiosity rover has landed on Mars, a smaller LEGO® plastic brick construction version could be landing in toy stores. Less than 2 weeks after Curiosity set down on 5 August, a LEGO® set concept model designed by a mechanical and aerospace engineer who worked on the real rover garnered its 10,000th supporter on the Web site of CUUSOO, a Japanese partner of the LEGO® group. That milestone triggered a company review that began in September 2012 to test the model's “playability, safety, and ft with the LEGO® brand,” according to a congratulatory statement from the company to designer Stephen Pakbaz. Pakbaz told Eos that he has been an avid LEGO® and space exploration fan for most of his life. “For me, creating a LEGO® model of Curiosity using my firsthand knowledge of the rover was inevitable. What I enjoyed most was being able to faithfully replicate and subsequently demonstrate the rocker-bogie suspension system to friends, family, and coworkers,” he noted, referring to the suspension system that allows the rover to climb over obstacles while keeping its wheels on the ground. Pakbaz, who is currently with Orbital Sciences Corporation, was involved with aspects of the rover while working at the Jet Propulsion Laboratory from 2007 to 2011 as a mechanical engineer.

An Analog Rover Exploration Mission for Education and Outreach

Science.gov (United States)

Moores, John; Campbell, Charissa L.; Smith, Christina L.; Cooper, Brittney A.

2017-10-01

This abstract describes an analog rover exploration mission designed as an outreach program for high school and undergraduate students. This program is used to teach them about basic mission control operations, how to manage a rover as if it were on another planetary body, and employing the rover remotely to complete mission objectives. One iteration of this program has been completed and another is underway. In both trials, participants were shown the different operation processes involved in a real-life mission. Modifications were made to these processes to decrease complexity and better simulate a mission control environment in a short time period (three 20-minute-long mission “days”). In the first run of the program, participants selected a landing site, what instruments would be on the rover - subject to cost, size, and weight limitations - and were randomly assigned one of six different mission operations roles, each with specific responsibilities. For example, a Science Planner/Integrator (SPI) would plan science activities whilst a Rover Engineer (RE) would keep on top of rover constraints. Planning consisted of a series of four meetings to develop and verify the current plan, pre-plan the next day's activities and uplink the activities to the “rover” (a human colleague). Participants were required to attend certain meetings depending upon their assigned role. To conclude the mission, students viewed the site to understand any differences between remote viewing and reality in relation to the rover. Another mission is currently in progress with revisions from the earlier run to improve the experience. This includes broader roles and meetings and pre-selecting the landing site and rover. The new roles are: Mission Lead, Rover Engineer and Science Planner. The SPI role was previously popular so most of the students were placed in this category. The meetings were reduced to three but extended in length. We are also planning to integrate this program

Risk-Aware Planetary Rover Operation: Autonomous Terrain Classification and Path Planning

Science.gov (United States)

Ono, Masahiro; Fuchs, Thoams J.; Steffy, Amanda; Maimone, Mark; Yen, Jeng

2015-01-01

Identifying and avoiding terrain hazards (e.g., soft soil and pointy embedded rocks) are crucial for the safety of planetary rovers. This paper presents a newly developed groundbased Mars rover operation tool that mitigates risks from terrain by automatically identifying hazards on the terrain, evaluating their risks, and suggesting operators safe paths options that avoids potential risks while achieving specified goals. The tool will bring benefits to rover operations by reducing operation cost, by reducing cognitive load of rover operators, by preventing human errors, and most importantly, by significantly reducing the risk of the loss of rovers.

Criticality safety for deactivation of the Rover dry headend process

International Nuclear Information System (INIS)

Henrikson, D.J.

1995-01-01

The Rover dry headend process combusted Rover graphite fuels in preparation for dissolution and solvent extraction for the recovery of 235 U. At the end of the Rover processing campaign, significant quantities of 235 U were left in the dry system. The Rover Dry Headend Process Deactivation Project goal is to remove the remaining uranium bearing material (UBM) from the dry system and then decontaminate the cells. Criticality safety issues associated with the Rover Deactivation Project have been influenced by project design refinement and schedule acceleration initiatives. The uranium ash composition used for calculations must envelope a wide range of material compositions, and yet result in cost effective final packaging and storage. Innovative thinking must be used to provide a timely safety authorization basis while the project design continues to be refined

Visual Prediction of Rover Slip: Learning Algorithms and Field Experiments

Science.gov (United States)

2008-01-01

of the terrain slope [29]. The results are also specific to the vehicle. For example, a small design modification in the pattern of the wheels can...robot has two front differential drive wheels and two rear caster wheels . 2This difference is not directly relevant to the goals of this work. 22 Figure...rover pose and is a quantity which measures the lack of progress of a wheeled ground robot while traversing some terrain. A trivial example of large

Performance of the Mechanically Pumped Fluid Loop Rover Heat Rejection System Used for Thermal Control of the Mars Science Laboratory Curiosity Rover on the Surface of Mars

Science.gov (United States)

Bhandari, Pradeep; Birur, Gajanana; Bame, David; Mastropietro, A. J.; Miller, Jennifer; Karlmann, Paul; Liu, Yuanming; Anderson, Kevin

2013-01-01

The challenging range of landing sites for which the Mars Science Laboratory Rover was designed, required a rover thermal management system that is capable of keeping temperatures controlled across a wide variety of environmental conditions. On the Martian surface where temperatures can be as cold as -123 C and as warm as 38 C, the Rover relies upon a Mechanically Pumped Fluid Loop (MPFL) Rover Heat Rejection System (RHRS) and external radiators to maintain the temperature of sensitive electronics and science instruments within a -40 C to +50 C range. The RHRS harnesses some of the waste heat generated from the Rover power source, known as the Multi Mission Radioisotope Thermoelectric Generator (MMRTG), for use as survival heat for the rover during cold conditions. The MMRTG produces 110 Watts of electrical power while generating waste heat equivalent to approximately 2000 Watts. Heat exchanger plates (hot plates) positioned close to the MMRTG pick up this survival heat from it by radiative heat transfer and supply it to the rover. This design is the first instance of use of a RHRS for thermal control of a rover or lander on the surface of a planet. After an extremely successful landing on Mars (August 5), the rover and the RHRS have performed flawlessly for close to an earth year (half the nominal mission life). This paper will share the performance of the RHRS on the Martian surface as well as compare it to its predictions.

Autonomous navigation and control of a Mars rover

Science.gov (United States)

Miller, D. P.; Atkinson, D. J.; Wilcox, B. H.; Mishkin, A. H.

1990-01-01

A Mars rover will need to be able to navigate autonomously kilometers at a time. This paper outlines the sensing, perception, planning, and execution monitoring systems that are currently being designed for the rover. The sensing is based around stereo vision. The interpretation of the images use a registration of the depth map with a global height map provided by an orbiting spacecraft. Safe, low energy paths are then planned through the map, and expectations of what the rover's articulation sensors should sense are generated. These expectations are then used to ensure that the planned path is correctly being executed.

Exomars 2018 Rover Pasteur Payload Sample Analysis

Science.gov (United States)

Debus, Andre; Bacher, M.; Ball, A.; Barcos, O.; Bethge, B.; Gaubert, F.; Haldemann, A.; Kminek, G.; Lindner, R.; Pacros, A.; Rohr, T.; Trautner, R.; Vago, J.

The ExoMars programme is a joint ESA-NASA program having exobiology as one of the key science objectives. It is divided into 2 missions: the first mission is ESA-led with an ESA orbiter and an ESA Entry, Descent and Landing (EDL) demonstrator, launched in 2016 by NASA, and the second mission is NASA-led, launched in 2018 by NASA including an ESA rover and a NASA rover both deployed by a single NASA EDL system. For ESA, the ExoMars programme will demonstrate key flight and in situ enabling technologies in support of the European ambitions for future exploration missions, as outlined in the Aurora Declaration. The ExoMars 2018 ESA Rover will carry a comprehensive and coherent suite of analytical instruments dedicated to exobiology and geology research: the Pasteur Payload (PPL). This payload includes a selection of complementary instruments, having the following goals: to search for signs of past and present life on Mars and to investigate the water/geochemical environment as a function of depth in the shallow subsurface. The ExoMars Rover will travel several kilometres searching for sites warranting further investigation. The Rover includes a drill and a Sample Preparation and Distribution System which will be used to collect and analyse samples from within outcrops and from the subsurface. The Rover systems and instruments, in particular those located inside the Analytical Laboratory Drawer must meet many stringent requirements to be compatible with exobiologic investigations: the samples must be maintained in a cold and uncontaminated environment, requiring sterile and ultraclean preparation of the instruments, to preserve volatile materials and to avoid false positive results. The value of the coordinated observations suggests that a significant return on investment is to be expected from this complex development. We will present the challenges facing the ExoMars PPL, and the plans for sending a robust exobiology laboratory to Mars in 2018.

Real‐Time Measurement of Wheel Performance on a Rover

Data.gov (United States)

National Aeronautics and Space Administration — Wind-blown sand on Mars produces a high risk of entrapment for Mars rovers. This was evident when the Mars Exploration Rover Spirit was immobilized in a wind blown...

Red rover: inside the story of robotic space exploration, from genesis to the mars rover curiosity

CERN Document Server

Wiens, Roger

2013-01-01

In its eerie likeness to Earth, Mars has long captured our imaginations—both as a destination for humankind and as a possible home to extraterrestrial life. It is our twenty-first century New World; its explorers robots, shipped 350 million miles from Earth to uncover the distant planet’s secrets.Its most recent scout is Curiosity—a one-ton, Jeep-sized nuclear-powered space laboratory—which is now roving the Martian surface to determine whether the red planet has ever been physically capable of supporting life. In Red Rover, geochemist Roger Wiens, the principal investigator for the ChemCam laser instrument on the rover and veteran of numerous robotic NASA missions, tells the unlikely story of his involvement in sending sophisticated hardware into space, culminating in the Curiosity rover's amazing journey to Mars.In so doing, Wiens paints the portrait of one of the most exciting scientific stories of our time: the new era of robotic space exploration. Starting with NASA’s introduction of the Discovery...

Development of "Remotely Operated Vehicles for Education and Research" (ROVERs)

Science.gov (United States)

Gaines, J. E.; Bland, G.; Bydlowski, D.

2017-12-01

The University of South Florida is a team member for the AREN project which develops educational technologies for data acquisition. "Remotely Operated Vehicles for Education and Research" (ROVERs) are floatable data acquisition systems used for Earth science measurements. The USF partnership was productive in the first year, resulting in new autonomous ROVER platforms being developed and used during a 5 week STEM summer camp by middle school youth. ROVERs were outfitted with GPS and temperature sensors and programmed to move forward, backwards, and to turn autonomously using the National Instruments myRIO embedded system. GLOBE protocols were used to collect data. The outreach program's structure lended itself to accomplishing an essential development effort for the AREN project towards the use of the ROVER platform in informal educational settings. A primary objective of the partnership is curriculum development to integrate GLOBE protocols and NASA technology and hardware/ROVER development wher new ROVER platforms are explored. The USF partnership resulted in two design prototypes for ROVERs, both of which can be created from recyclable materials for flotation and either 3D printed or laser cut components. In addition, both use the National Instruments myRIO for autonomous control. We will present two prototypes designed for use during the USF outreach program, the structure of the program, and details on the fabrication of prototype Z during the program by middle school students. Considering the 5-year objective of the AREN project is to "develop approaches, learning plans, and specific tools that can be affordably implemented nationwide (globally)", the USF partnership is key as it contributes to each part of the objective in a unique and impactful way.

The Challenges in Applying Magnetroesistive Sensors on the 'Curiosity' Rover

Science.gov (United States)

Johnson, Michael R.

2013-01-01

Magnetoresistive Sensors were selected for use on the motor encoders throughout the Curiosity Rover for motor position feedback devices. The Rover contains 28 acuators with a corresponding number of encoder assemblies. The environment on Mars provides opportunities for challenges to any hardware design. The encoder assemblies presented several barriers that had to be vaulted in order to say the rover was ready to fly. The environment and encoder specific design features provided challenges that had to be solved in time to fly.

Panoramic 3d Vision on the ExoMars Rover

Science.gov (United States)

Paar, G.; Griffiths, A. D.; Barnes, D. P.; Coates, A. J.; Jaumann, R.; Oberst, J.; Gao, Y.; Ellery, A.; Li, R.

.r.t. fields of view, ranging capability (distance measurement capability), data rate, necessity of calibration targets, hardware & data interfaces to other subsystems (e.g. navigation) as well as accuracy impacts of sensor design and compression ratio. • Geometric Calibration: The geometric properties of the individual cameras including various spectral filters, their mutual relations and the dynamic geometrical relation between rover frame and cameras - with the mast in between - are precisely described by a calibration process. During surface operations these relations will be continuously checked and updated by photogrammetric means, environmental influences such as temperature, pressure and the Mars gravity will be taken into account. • Surface Mapping: Stereo imaging using the WAC stereo pair is used for the 3d reconstruction of the rover vicinity to identify, locate and characterize potentially interesting spots (3-10 for an experimental cycle to be performed within approx. 10-30 sols). The HRC is used for high resolution imagery of these regions of interest to be overlaid on the 3d reconstruction and potentially refined by shape-from-shading techniques. A quick processing result is crucial for time critical operations planning, therefore emphasis is laid on the automatic behaviour and intrinsic error detection mechanisms. The mapping results will be continuously fused, updated and synchronized with the map used by the navigation system. The surface representation needs to take into account the different resolutions of HRC and WAC as well as uncommon or even unexpected image acquisition modes such as long range, wide baseline stereo from different rover positions or escape strategies in the case of loss of one of the stereo camera heads. • Panorama Mosaicking: The production of a high resolution stereoscopic panorama nowadays is state-of-art in computer vision. However, certain 2 challenges such as the need for access to accurate spherical coordinates, maintenance

Mars Exploration Rover Heat Shield Recontact Analysis

Science.gov (United States)

Raiszadeh, Behzad; Desai, Prasun N.; Michelltree, Robert

2011-01-01

The twin Mars Exploration Rover missions landed successfully on Mars surface in January of 2004. Both missions used a parachute system to slow the rover s descent rate from supersonic to subsonic speeds. Shortly after parachute deployment, the heat shield, which protected the rover during the hypersonic entry phase of the mission, was jettisoned using push-off springs. Mission designers were concerned about the heat shield recontacting the lander after separation, so a separation analysis was conducted to quantify risks. This analysis was used to choose a proper heat shield ballast mass to ensure successful separation with low probability of recontact. This paper presents the details of such an analysis, its assumptions, and the results. During both landings, the radar was able to lock on to the heat shield, measuring its distance, as it descended away from the lander. This data is presented and is used to validate the heat shield separation/recontact analysis.

Pressure Myography to Study the Function and Structure of isolated small arteries

DEFF Research Database (Denmark)

Schjørring, Olav; Carlsson, Rune; Simonsen, Ulf

2015-01-01

Small arteries play an important role in regulation of peripheral resistance and organ perfusion. Here we describe a series of the methods allowing measurements in pressurized segments of small arteries from the systemic and coronary circulation of mice as well as other species. The pressure...... myography techniques described include measurements of wall structure, wall stress, strain, and of myogenic tone. The pressurized perfused small arteries also allow evaluation of responses to increases in pressure, flow, and drugs, where the main readout is changes in vascular diameter....

Mars 2020 Rover SHERLOC Calibration Target

Science.gov (United States)

Graff, Trevor; Fries, Marc; Burton, Aaron; Ross, Amy; Larson, Kristine; Garrison, Dan; Calaway, Mike; Tran, Vinh; Bhartia, Roh; Beegle, Luther

2016-01-01

The Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals (SHERLOC) instrument is a deep ultraviolet (UV) Raman Fluorescence instrument selected as part of the Mars 2020 rover instrument suite. SHERLOC will be mounted on the rover arm and its primary role is to identify carbonaceous species in martian samples. The SHERLOC instrument requires a calibration target which is being designed and fabricated at JSC as part of our continued science participation in Mars robotic missions. The SHERLOC calibration target will address a wide range of NASA goals to include basic science of interest to both the Science Mission Directorate and Human Exploration and Operations Mission Directorate.

Autonomously Generating Operations Sequences for a Mars Rover Using Artificial Intelligence-Based Planning

Science.gov (United States)

Sherwood, R.; Mutz, D.; Estlin, T.; Chien, S.; Backes, P.; Norris, J.; Tran, D.; Cooper, B.; Rabideau, G.; Mishkin, A.; Maxwell, S.

2001-07-01

This article discusses a proof-of-concept prototype for ground-based automatic generation of validated rover command sequences from high-level science and engineering activities. This prototype is based on ASPEN, the Automated Scheduling and Planning Environment. This artificial intelligence (AI)-based planning and scheduling system will automatically generate a command sequence that will execute within resource constraints and satisfy flight rules. An automated planning and scheduling system encodes rover design knowledge and uses search and reasoning techniques to automatically generate low-level command sequences while respecting rover operability constraints, science and engineering preferences, environmental predictions, and also adhering to hard temporal constraints. This prototype planning system has been field-tested using the Rocky 7 rover at JPL and will be field-tested on more complex rovers to prove its effectiveness before transferring the technology to flight operations for an upcoming NASA mission. Enabling goal-driven commanding of planetary rovers greatly reduces the requirements for highly skilled rover engineering personnel. This in turn greatly reduces mission operations costs. In addition, goal-driven commanding permits a faster response to changes in rover state (e.g., faults) or science discoveries by removing the time-consuming manual sequence validation process, allowing rapid "what-if" analyses, and thus reducing overall cycle times.

The Design of Two Nano-Rovers for Lunar Surface Exploration in the Context of the Google Lunar X Prize

Science.gov (United States)

Gill, E.; Honfi Camilo, L.; Kuystermans, P.; Maas, A. S. B. B.; Buutfeld, B. A. M.; van der Pols, R. H.

2008-09-01

This paper summarizes a study performed by ten students at the Delft University of Technology on a lunar exploration vehicle suited for competing in the Google Lunar X Prize1. The design philosophy aimed at a quick and simple design process, to comply with the mission constraints. This is achieved by using conventional technology and performing the mission with two identical rovers, increasing reliability and simplicity of systems. Both rovers are however capable of operating independently. The required subsystems have been designed for survival and operation on the lunar surface for an estimated mission lifetime of five days. This preliminary study shows that it is possible for two nano-rovers to perform the basic exploration tasks. The mission has been devised such that after launch the rovers endure a 160 hour voyage to the Moon after which they will land on Sinus Medii with a dedicated lunar transfer/lander vehicle. The mission outline itself has the two nano-rovers travelling in the same direction, moving simultaneously. This mission characteristic allows a quick take-over of the required tasks by the second rover in case of one rover breakdown. The main structure of the rovers will consist of Aluminium 2219 T851, due to its good thermal properties and high hardness. Because of the small dimensions of the rovers, the vehicles will use rigid caterpillar tracks as locomotion system. The track systems are sealed from lunar dust using closed track to prevent interference with the mechanisms. This also prevents any damage to the electronics inside the tracks. For the movement speed a velocity of 0.055 m/s has been determined. This is about 90% of the maximum rover velocity, allowing direct control from Earth. The rovers are operated by a direct control loop, involving the mission control center. In order to direct the rovers safely, a continuous video link with the Earth is necessary to assess its immediate surroundings. Two forward pointing navigational cameras

Conceptual Design and Architecture of Mars Exploration Rover (MER) for Seismic Experiments Over Martian Surfaces

Science.gov (United States)

Garg, Akshay; Singh, Amit

2012-07-01

Keywords: MER, Mars, Rover, Seismometer Mars has been a subject of human interest for exploration missions for quite some time now. Both rover as well as orbiter missions have been employed to suit mission objectives. Rovers have been preferentially deployed for close range reconnaissance and detailed experimentation with highest accuracy. However, it is essential to strike a balance between the chosen science objectives and the rover operations as a whole. The objective of this proposed mechanism is to design a vehicle (MER) to carry out seismic studies over Martian surface. The conceptual design consists of three units i.e. Mother Rover as a Surrogate (Carrier) and Baby Rovers (two) as seeders for several MEMS-based accelerometer / seismometer units (Nodes). Mother Rover can carry these Baby Rovers, having individual power supply with solar cells and with individual data transmission capabilities, to suitable sites such as Chasma associated with Valles Marineris, Craters or Sand Dunes. Mother rover deploys these rovers in two opposite direction and these rovers follow a triangulation pattern to study shock waves generated through firing tungsten carbide shells into the ground. Till the time of active experiments Mother Rover would act as a guiding unit to control spatial spread of detection instruments. After active shock experimentation, the babies can still act as passive seismometer units to study and record passive shocks from thermal quakes, impact cratering & landslides. Further other experiments / payloads (XPS / GAP / APXS) can also be carried by Mother Rover. Secondary power system consisting of batteries can also be utilized for carrying out further experiments over shallow valley surfaces. The whole arrangement is conceptually expected to increase the accuracy of measurements (through concurrent readings) and prolong life cycle of overall experimentation. The proposed rover can be customised according to the associated scientific objectives and further

Autonomous Rover Traverse and Precise Arm Placement on Remotely Designated Targets

Science.gov (United States)

Felder, Michael; Nesnas, Issa A.; Pivtoraiko, Mihail; Kelly, Alonzo; Volpe, Richard

2011-01-01

Exploring planetary surfaces typically involves traversing challenging and unknown terrain and acquiring in-situ measurements at designated locations using arm-mounted instruments. We present field results for a new implementation of an autonomous capability that enables a rover to traverse and precisely place an arm-mounted instrument on remote targets. Using point-and-click mouse commands, a scientist designates targets in the initial imagery acquired from the rover's mast cameras. The rover then autonomously traverse the rocky terrain for a distance of 10 - 15 m, tracks the target(s) of interest during the traverse, positions itself for approaching the target, and then precisely places an arm-mounted instrument within 2-3 cm from the originally designated target. The rover proceeds to acquire science measurements with the instrument. This work advances what has been previously developed and integrated on the Mars Exploration Rovers by using algorithms that are capable of traversing more rock-dense terrains, enabling tight thread-the-needle maneuvers. We integrated these algorithms on the newly refurbished Athena Mars research rover and fielded them in the JPL Mars Yard. We conducted 43 runs with targets at distances ranging from 5 m to 15 m and achieved a success rate of 93% for placement of the instrument within 2-3 cm.

Comparative Field Tests of Pressurised Rover Prototypes

Science.gov (United States)

Mann, G. A.; Wood, N. B.; Clarke, J. D.; Piechochinski, S.; Bamsey, M.; Laing, J. H.

The conceptual designs, interior layouts and operational performances of three pressurised rover prototypes - Aonia, ARES and Everest - were field tested during a recent simulation at the Mars Desert Research Station in Utah. A human factors experiment, in which the same crew of three executed the same simulated science mission in each of the three vehicles, yielded comparative data on the capacity of each vehicle to safely and comfortably carry explorers away from the main base, enter and exit the vehicle in spacesuits, perform science tasks in the field, and manage geological and biological samples. As well as offering recommendations for design improvements for specific vehicles, the results suggest that a conventional Sports Utility Vehicle (SUV) would not be suitable for analog field work; that a pressurised docking tunnel to the main habitat is essential; that better provisions for spacesuit storage are required; and that a crew consisting of one driver/navigator and two field science crew specialists may be optimal. From a field operations viewpoint, a recurring conflict between rover and habitat crews at the time of return to the habitat was observed. An analysis of these incidents leads to proposed refinements of operational protocols, specific crew training for rover returns and again points to the need for a pressurised docking tunnel. Sound field testing, circulating of results, and building the lessons learned into new vehicles is advocated as a way of producing ever higher fidelity rover analogues.

Absolute Navigation Information Estimation for Micro Planetary Rovers

Directory of Open Access Journals (Sweden)

Muhammad Ilyas

2016-03-01

Full Text Available This paper provides algorithms to estimate absolute navigation information, e.g., absolute attitude and position, by using low power, weight and volume Microelectromechanical Systems-type (MEMS sensors that are suitable for micro planetary rovers. Planetary rovers appear to be easily navigable robots due to their extreme slow speed and rotation but, unfortunately, the sensor suites available for terrestrial robots are not always available for planetary rover navigation. This makes them difficult to navigate in a completely unexplored, harsh and complex environment. Whereas the relative attitude and position can be tracked in a similar way as for ground robots, absolute navigation information, unlike in terrestrial applications, is difficult to obtain for a remote celestial body, such as Mars or the Moon. In this paper, an algorithm called the EASI algorithm (Estimation of Attitude using Sun sensor and Inclinometer is presented to estimate the absolute attitude using a MEMS-type sun sensor and inclinometer, only. Moreover, the output of the EASI algorithm is fused with MEMS gyros to produce more accurate and reliable attitude estimates. An absolute position estimation algorithm has also been presented based on these on-board sensors. Experimental results demonstrate the viability of the proposed algorithms and the sensor suite for low-cost and low-weight micro planetary rovers.

Dynamic Modeling and Soil Mechanics for Path Planning of the Mars Exploration Rovers

Science.gov (United States)

Trease, Brian; Arvidson, Raymond; Lindemann, Randel; Bennett, Keith; Zhou, Feng; Iagnemma, Karl; Senatore, Carmine; Van Dyke, Lauren

2011-01-01

To help minimize risk of high sinkage and slippage during drives and to better understand soil properties and rover terramechanics from drive data, a multidisciplinary team was formed under the Mars Exploration Rover (MER) project to develop and utilize dynamic computer-based models for rover drives over realistic terrains. The resulting tool, named ARTEMIS (Adams-based Rover Terramechanics and Mobility Interaction Simulator), consists of the dynamic model, a library of terramechanics subroutines, and the high-resolution digital elevation maps of the Mars surface. A 200-element model of the rovers was developed and validated for drop tests before launch, using MSC-Adams dynamic modeling software. Newly modeled terrain-rover interactions include the rut-formation effect of deformable soils, using the classical Bekker-Wong implementation of compaction resistances and bull-dozing effects. The paper presents the details and implementation of the model with two case studies based on actual MER telemetry data. In its final form, ARTEMIS will be used in a predictive manner to assess terrain navigability and will become part of the overall effort in path planning and navigation for both Martian and lunar rovers.

Archiving Data From the 2003 Mars Exploration Rover Mission

Science.gov (United States)

Arvidson, R. E.

2002-12-01

The two Mars Exploration Rovers will touch down on the red planet in January 2004 and each will operate for at least 90 sols, traversing hundreds of meters across the surface and acquiring data from the Athena Science Payload (mast-based multi-spectral, stereo-imaging data and emission spectra; arm-based in-situ Alpha Particle X-Ray (APXS) and Mössbauer Spectroscopy, microscopic imaging, coupled with use of a rock abrasion tool) at a number of locations. In addition, the rovers will acquire science and engineering data along traverses to characterize terrain properties and perhaps be used to dig trenches. An "Analyst's Notebook" concept has been developed to capture, organize, archive and distribute raw and derived data sets and documentation (http://wufs.wustl.edu/rover). The Notebooks will be implemented in ways that will allow users to "playback" the mission, using executed commands to drive animated views of rover activities, and pop-up windows to show why particular observations were acquired, along with displays of raw and derived data products. In addition, the archive will include standard Planetary Data System files and software for processing to higher-level products. The Notebooks will exist both as an online system and as a set of distributable Digital Video Discs or other appropriate media. The Notebooks will be made available through the Planetary Data System within six months after the end of observations for the relevant rovers.

Design and Demonstration of a Miniature Lidar System for Rover Applications

Science.gov (United States)

Robinson, Benjamin

2010-01-01

A basic small and portable lidar system for rover applications has been designed. It uses a 20 Hz Nd:YAG pulsed laser, a 4-inch diameter telescope receiver, a custom-built power distribution unit (PDU), and a custom-built 532 nm photomultiplier tube (PMT) to measure the lidar signal. The receiving optics have been designed, but not constructed yet. LabVIEW and MATLAB programs have also been written to control the system, acquire data, and analyze data. The proposed system design, along with some measurements, is described. Future work to be completed is also discussed.

Transportable, small high-pressure preservation vessel for cells

International Nuclear Information System (INIS)

Kamimura, N; Sotome, S; Shimizu, A; Nakajima, K; Yoshimura, Y

2010-01-01

We have previously reported that the survival rate of astrocytes increases under high-pressure conditions at 4 0 C. However, pressure vessels generally have numerous problems for use in cell preservation and transportation: (1) they cannot be readily separated from the pressurizing pump in the pressurized state; (2) they are typically heavy and expensive due the use of materials such as stainless steel; and (3) it is difficult to regulate pressurization rate with hand pumps. Therefore, we developed a transportable high-pressure system suitable for cell preservation under high-pressure conditions. This high-pressure vessel has the following characteristics: (1) it can be easily separated from the pressurizing pump due to the use of a cock-type stop valve; (2) it is small and compact, is made of PEEK and weighs less than 200 g; and (3) pressurization rate is regulated by an electric pump instead of a hand pump. Using this transportable high-pressure vessel for cell preservation, we found that astrocytes can survive for 4 days at 1.6 MPa and 4 0 C.

The University Rover Challenge: A competition highlighting Human and Robotic partnerships for exploration

Science.gov (United States)

Smith, Heather; Duncan, Andrew

2016-07-01

The University Rover Challenge began in 2006 with 4 American college teams competing, now in it's 10th year there are 63 teams from 12 countries registered to compete for the top rover designed to assist humans in the exploration of Mars. The Rovers compete aided by the University teams in four tasks (3 engineering and 1 science) in the Mars analog environment of the Utah Southern Desert in the United States. In this presentation we show amazing rover designs with videos demonstrating the incredible ingenuity, skill and determination of the world's most talented college students. We describe the purpose and results of each of the tasks: Astronaut Assistant, Rover Dexterity, Terrain maneuvering, and Science. We explain the evolution of the competition and common challenges faced by the robotic explorers

(abstract) Telecommunications for Mars Rovers and Robotic Missions

Science.gov (United States)

Cesarone, Robert J.; Hastrup, Rolf C.; Horne, William; McOmber, Robert

1997-01-01

Telecommunications plays a key role in all rover and robotic missions to Mars both as a conduit for command information to the mission and for scientific data from the mission. Telecommunications to the Earth may be accomplished using direct-to-Earth links via the Deep Space Network (DSN) or by relay links supported by other missions at Mars. This paper reviews current plans for missions to Mars through the 2005 launch opportunity and their capabilities in support of rover and robotic telecommunications.

Nuclear thermal rocket workshop reference system Rover/NERVA

International Nuclear Information System (INIS)

Borowski, S.K.

1991-01-01

The Rover/NERVA engine system is to be used as a reference, against which each of the other concepts presented in the workshop will be compared. The following topics are reviewed: the operational characteristics of the nuclear thermal rocket (NTR); the accomplishments of the Rover/NERVA programs; and performance characteristics of the NERVA-type systems for both Mars and lunar mission applications. Also, the issues of ground testing, NTR safety, NASA's nuclear propulsion project plans, and NTR development cost estimates are briefly discussed

Design of a nuclear-powered rover for lunar or Martian exploration

International Nuclear Information System (INIS)

Trellue, H.R.; Trautner, R.; Houts, M.G.; Poston, D.I.; Giovig, K.; Baca, J.A.; Lipinski, R.J.

1998-08-01

To perform more advanced studies on the surface of the moon or Mars, a rover must provide long-term power (≥10 kW e ). However, a majority of rovers in the past have been designed for much lower power levels (i.e., on the order of watts) or for shorter operating periods using stored power. Thus, more advanced systems are required to generate additional power. One possible design for a more highly powered rover involves using a nuclear reactor to supply energy to the rover and material from the surface of the moon or Mars to shield the electronics from high neutron fluxes and gamma doses. Typically, one of the main disadvantages of using a nuclear-powered rover is that the required shielding would be heavy and expensive to include as part of the payload on a mission. Obtaining most of the required shielding material from the surface of the moon or Mars would reduce the cost of the mission and still provide the necessary power. This paper describes the basic design of a rover that uses the Heatpipe Power System (HPS) as an energy source, including the shielding and reactor control issues associated with the design. It also discusses briefly the amount of power that can be produced by other power methods (solar/photovoltaic cells, radioisotope power supplies, dynamic radioisotope power systems, and the production of methane or acetylene fuel from the surface of Mars) as a comparison to the HPS

Electrostatic Spectrometer for Mars Rover Wheel

Data.gov (United States)

National Aeronautics and Space Administration — Develop a simple electrostatic spectrometer that can be mounted on the wheels of a Mars rover to continuously and unobtrusively determine the mineral composition and...

A Battery Health Monitoring Framework for Planetary Rovers

Science.gov (United States)

Daigle, Matthew J.; Kulkarni, Chetan Shrikant

2014-01-01

Batteries have seen an increased use in electric ground and air vehicles for commercial, military, and space applications as the primary energy source. An important aspect of using batteries in such contexts is battery health monitoring. Batteries must be carefully monitored such that the battery health can be determined, and end of discharge and end of usable life events may be accurately predicted. For planetary rovers, battery health estimation and prediction is critical to mission planning and decision-making. We develop a model-based approach utilizing computaitonally efficient and accurate electrochemistry models of batteries. An unscented Kalman filter yields state estimates, which are then used to predict the future behavior of the batteries and, specifically, end of discharge. The prediction algorithm accounts for possible future power demands on the rover batteries in order to provide meaningful results and an accurate representation of prediction uncertainty. The framework is demonstrated on a set of lithium-ion batteries powering a rover at NASA.

Reconfigurable Autonomy for Future Planetary Rovers

Science.gov (United States)

Burroughes, Guy

Extra-terrestrial Planetary rover systems are uniquely remote, placing constraints in regard to communication, environmental uncertainty, and limited physical resources, and requiring a high level of fault tolerance and resistance to hardware degradation. This thesis presents a novel self-reconfiguring autonomous software architecture designed to meet the needs of extraterrestrial planetary environments. At runtime it can safely reconfigure low-level control systems, high-level decisional autonomy systems, and managed software architecture. The architecture can perform automatic Verification and Validation of self-reconfiguration at run-time, and enables a system to be self-optimising, self-protecting, and self-healing. A novel self-monitoring system, which is non-invasive, efficient, tunable, and autonomously deploying, is also presented. The architecture was validated through the use-case of a highly autonomous extra-terrestrial planetary exploration rover. Three major forms of reconfiguration were demonstrated and tested: first, high level adjustment of system internal architecture and goal; second, software module modification; and third, low level alteration of hardware control in response to degradation of hardware and environmental change. The architecture was demonstrated to be robust and effective in a Mars sample return mission use-case testing the operational aspects of a novel, reconfigurable guidance, navigation, and control system for a planetary rover, all operating in concert through a scenario that required reconfiguration of all elements of the system.

Pilot-plant development of a Rover waste calcination flowsheet

International Nuclear Information System (INIS)

Birrer, S.A.

1978-04-01

Results of eight runs, six using the 10-cm dia and two using the 30-cm dia pilot-plant calciners, in which simulated first-cycle Rover waste was calcined, are described. Results of the tests showed that a feed blend consisting of one volume simulated first-cycle Rover waste and one or two volumes simulated first-cycle zirconium waste could not be successfully calcined. 5 figs., 8 tables

A Virtual Simulation Environment for Lunar Rover: Framework and Key Technologies

Directory of Open Access Journals (Sweden)

Yan-chun Yang

2008-11-01

Full Text Available Lunar rover development involves a large amount of validation works in realistic operational conditions, including its mechanical subsystem and on-board software. Real tests require equipped rover platform and a realistic terrain. It is very time consuming and high cost. To improve the development efficiency, a rover simulation environment called RSVE that affords real time capabilities with high fidelity has been developed. It uses fractional Brown motion (fBm technique and statistical properties to generate lunar surface. Thus, various terrain models for simulation can be generated through changing several parameters. To simulate lunar rover evolving on natural and unstructured surface with high realism, the whole dynamics of the multi-body systems and complex interactions with soft ground is integrated in this environment. An example for path planning algorithm and controlling algorithm testing in this environment is tested. This simulation environment runs on PC or Silicon Graphics.

A Virtual Simulation Environment for Lunar Rover: Framework and Key Technologies

Directory of Open Access Journals (Sweden)

Yan-chun Yang

2008-06-01

Full Text Available Lunar rover development involves a large amount of validation works in realistic operational conditions, including its mechanical subsystem and on-board software. Real tests require equipped rover platform and a realistic terrain. It is very time consuming and high cost. To improve the development efficiency, a rover simulation environment called RSVE that affords real time capabilities with high fidelity has been developed. It uses fractional Brown motion (fBm technique and statistical properties to generate lunar surface. Thus, various terrain models for simulation can be generated through changing several parameters. To simulate lunar rover evolving on natural and unstructured surface with high realism, the whole dynamics of the multi-body systems and complex interactions with soft ground is integrated in this environment. An example for path planning algorithm and controlling algorithm testing in this environment is tested. This simulation environment runs on PC or Silicon Graphics.

Frost on Mars Rover Opportunity

Science.gov (United States)

2004-01-01

Frost can form on surfaces if enough water is present and the temperature is sufficiently low. On each of NASA's Mars Exploration Rovers, the calibration target for the panoramic camera provides a good place to look for such events. A thin frost was observed by Opportunity's panoramic camera on the rover's 257th sol (Oct. 13, 2004) 11 minutes after sunrise (left image). The presence of the frost is most clearly seen on the post in the center of the target, particularly when compared with the unsegmented outer ring of the target, which is white. The post is normally black. For comparison, note the difference in appearance in the image on the right, taken about three hours later, after the frost had dissipated. Frost has not been observed at Spirit, where the amount of atmospheric water vapor is observed to be appreciably lower. Both images were taken through a filter centered at a wavelength of 440 nanometers (blue).

A Raman Spectrometer for the ExoMars 2020 Rover

Science.gov (United States)

Moral, A. G.; Rull, F.; Maurice, S.; Hutchinson, I.; Canora, C. P.; Seoane, L.; Rodríguez, P.; Canchal, R.; Gallego, P.; Ramos, G.; López, G.; Prieto, J. A. R.; Santiago, A.; Santamaría, P.; Colombo, M.; Belenguer, T.; Forni, O.

2017-09-01

The Raman project is devoted to the development of a Raman spectrometer and the support science associated for the rover EXOMARS mission to be launched in 2020. ExoMars is a double mission with two different launch opportunities, first one launched in March 2016 allowed to put in orbit the TGO with the communication system for the next mission. And the second one in 2020, deploying a rover which includes for the first time in the robotic exploration of Mars, a drill capable to obtain samples from the subsurface up to 2 meters depth. These samples will be crushed into a fine powder and delivered to the analytical instruments suite inside the rover by means of a dosing station. The EQM has been already qualified under a very demanding thermo mechanical environment, and under EMC tests, finally achieving required scientific performances. The RLS Engineering and Qualification Model has been manufactured and is expected to be delivered by May 2017, after a full qualification testing campaign developed during 2016 Q4, and 2017 Q1. It will finally delivered to ESA, by July 2017. December 2017 at TAS-I premises will do RLS FM delivery to ESA, for its final integration on the ExoMars 2020 Rover.

Propulsive maneuver design for the Mars Exploration Rover mission

Science.gov (United States)

Potts, Christopher L.; Kangas, Julie A.; Raofi, Behzad

2006-01-01

Starting from approximately 150 candidate Martian landing sites, two distinct sites have been selected for further investigation by sophisticated rovers. The two rovers, named 'Spirit' and 'Opportunity', begin the surface mission respectively to Gusec Crater and Meridiani Planum in January 2004. the rovers are essentially robotic geologists, sent on a mission to research for evidence in the rocks and soil pertaining to the historical presence of water and the ability to possibly sustain life. Before this scientific search can commence, precise trajectory targeting and control is necessary to achieve the entry requirements for the selected landing sites within the constraints of the flight system. The maneuver design challenge is to meet or exceed these requirements while maintaining the necessary design flexibility to accommodate additional project concerns. Opportunities to improve performance and reduce risk based on trajectory control characteristics are also evaluated.

Design of Mobility System for Ground Model of Planetary Exploration Rover

Directory of Open Access Journals (Sweden)

Younkyu Kim

2012-12-01

Full Text Available In recent years, a number of missions have been planned and conducted worldwide on the planets such as Mars, which involves the unmanned robotic exploration with the use of rover. The rover is an important system for unmanned planetary exploration, performing the locomotion and sample collection and analysis at the exploration target of the planetary surface designated by the operator. This study investigates the development of mobility system for the rover ground model necessary to the planetary surface exploration for the benefit of future planetary exploration mission in Korea. First, the requirements for the rover mobility system are summarized and a new mechanism is proposed for a stable performance on rough terrain which consists of the passive suspension system with 8 wheeled double 4-bar linkage (DFBL, followed by the performance evaluation for the mechanism of the mobility system based on the shape design and simulation. The proposed mobility system DFBL was compared with the Rocker-Bogie suspension system of US space agency National Aeronautics and Space Administration and 8 wheeled mobility system CRAB8 developed in Switzerland, using the simulation to demonstrate the superiority with respect to the stability of locomotion. On the basis of the simulation results, a general system configuration was proposed and designed for the rover manufacture.

Accessing Information on the Mars Exploration Rovers Mission

Science.gov (United States)

Walton, J. D.; Schreiner, J. A.

2005-12-01

In January 2004, the Mars Exploration Rovers (MER) mission successfully deployed two robotic geologists - Spirit and Opportunity - to opposite sides of the red planet. Onboard each rover is an array of cameras and scientific instruments that send data back to Earth, where ground-based systems process and store the information. During the height of the mission, a team of about 250 scientists and engineers worked around the clock to analyze the collected data, determine a strategy and activities for the next day and then carefully compose the command sequences that would instruct the rovers in how to perform their tasks. The scientists and engineers had to work closely together to balance the science objectives with the engineering constraints so that the mission achieved its goals safely and quickly. To accomplish this coordinated effort, they adhered to a tightly orchestrated schedule of meetings and processes. To keep on time, it was critical that all team members were aware of what was happening, knew how much time they had to complete their tasks, and could easily access the information they need to do their jobs. Computer scientists and software engineers at NASA Ames Research Center worked closely with the mission managers at the Jet Propulsion Laboratory (JPL) to create applications that support the mission. One such application, the Collaborative Information Portal (CIP), helps mission personnel perform their daily tasks, whether they work inside mission control or the science areas at JPL, or in their homes, schools, or offices. With a three-tiered, service-oriented architecture (SOA) - client, middleware, and data repository - built using Java and commercial software, CIP provides secure access to mission schedules and to data and images transmitted from the Mars rovers. This services-based approach proved highly effective for building distributed, flexible applications, and is forming the basis for the design of future mission software systems. Almost two

Mars Exploration Rover Spirit End of Mission Report

Science.gov (United States)

Callas, John L.

2015-01-01

The Mars Exploration Rover (MER) Spirit landed in Gusev crater on Mars on January 4, 2004, for a prime mission designed to last three months (90 sols). After more than six years operating on the surface of Mars, the last communication received from Spirit occurred on Sol 2210 (March 22, 2010). Following the loss of signal, the Mars Exploration Rover Project radiated over 1400 commands to Mars in an attempt to elicit a response from the rover. Attempts were made utilizing Deep Space Network X-Band and UHF relay via both Mars Odyssey and the Mars Reconnaissance Orbiter. Search and recovery efforts concluded on July 13, 2011. It is the MER project's assessment that Spirit succumbed to the extreme environmental conditions experienced during its fourth winter on Mars. Focusing on the time period from the end of the third Martian winter through the fourth winter and end of recovery activities, this report describes possible explanations for the loss of the vehicle and the extent of recovery efforts that were performed. It offers lessons learned and provides an overall mission summary.

Estimation and Control for Autonomous Coring from a Rover Manipulator

Science.gov (United States)

Hudson, Nicolas; Backes, Paul; DiCicco, Matt; Bajracharya, Max

2010-01-01

A system consisting of a set of estimators and autonomous behaviors has been developed which allows robust coring from a low-mass rover platform, while accommodating for moderate rover slip. A redundant set of sensors, including a force-torque sensor, visual odometry, and accelerometers are used to monitor discrete critical and operational modes, as well as to estimate continuous drill parameters during the coring process. A set of critical failure modes pertinent to shallow coring from a mobile platform is defined, and autonomous behaviors associated with each critical mode are used to maintain nominal coring conditions. Autonomous shallow coring is demonstrated from a low-mass rover using a rotary-percussive coring tool mounted on a 5 degree-of-freedom (DOF) arm. A new architecture of using an arm-stabilized, rotary percussive tool with the robotic arm used to provide the drill z-axis linear feed is validated. Particular attention to hole start using this architecture is addressed. An end-to-end coring sequence is demonstrated, where the rover autonomously detects and then recovers from a series of slip events that exceeded 9 cm total displacement.

Dual-EKF-Based Real-Time Celestial Navigation for Lunar Rover

Directory of Open Access Journals (Sweden)

Li Xie

2012-01-01

Full Text Available A key requirement of lunar rover autonomous navigation is to acquire state information accurately in real-time during its motion and set up a gradual parameter-based nonlinear kinematics model for the rover. In this paper, we propose a dual-extended-Kalman-filter- (dual-EKF- based real-time celestial navigation (RCN method. The proposed method considers the rover position and velocity on the lunar surface as the system parameters and establishes a constant velocity (CV model. In addition, the attitude quaternion is considered as the system state, and the quaternion differential equation is established as the state equation, which incorporates the output of angular rate gyroscope. Therefore, the measurement equation can be established with sun direction vector from the sun sensor and speed observation from the speedometer. The gyro continuous output ensures the algorithm real-time operation. Finally, we use the dual-EKF method to solve the system equations. Simulation results show that the proposed method can acquire the rover position and heading information in real time and greatly improve the navigation accuracy. Our method overcomes the disadvantage of the cumulative error in inertial navigation.

GIS Methodology for Planning Planetary-Rover Operations

Science.gov (United States)

Powell, Mark; Norris, Jeffrey; Fox, Jason; Rabe, Kenneth; Shu, I-Hsiang

2007-01-01

A document describes a methodology for utilizing image data downlinked from cameras aboard a robotic ground vehicle (rover) on a remote planet for analyzing and planning operations of the vehicle and of any associated spacecraft. Traditionally, the cataloging and presentation of large numbers of downlinked planetary-exploration images have been done by use of two organizational methods: temporal organization and correlation between activity plans and images. In contrast, the present methodology involves spatial indexing of image data by use of the computational discipline of geographic information systems (GIS), which has been maturing in terrestrial applications for decades, but, until now, has not been widely used in support of exploration of remote planets. The use of GIS to catalog data products for analysis is intended to increase efficiency and effectiveness in planning rover operations, just as GIS has proven to be a source of powerful computational tools in such terrestrial endeavors as law enforcement, military strategic planning, surveying, political science, and epidemiology. The use of GIS also satisfies the need for a map-based user interface that is intuitive to rover-activity planners, many of whom are deeply familiar with maps and know how to use them effectively in field geology.

Mission Operations of the Mars Exploration Rovers

Science.gov (United States)

Bass, Deborah; Lauback, Sharon; Mishkin, Andrew; Limonadi, Daniel

2007-01-01

A document describes a system of processes involved in planning, commanding, and monitoring operations of the rovers Spirit and Opportunity of the Mars Exploration Rover mission. The system is designed to minimize command turnaround time, given that inherent uncertainties in terrain conditions and in successful completion of planned landed spacecraft motions preclude planning of some spacecraft activities until the results of prior activities are known by the ground-based operations team. The processes are partitioned into those (designated as tactical) that must be tied to the Martian clock and those (designated strategic) that can, without loss, be completed in a more leisurely fashion. The tactical processes include assessment of downlinked data, refinement and validation of activity plans, sequencing of commands, and integration and validation of sequences. Strategic processes include communications planning and generation of long-term activity plans. The primary benefit of this partition is to enable the tactical portion of the team to focus solely on tasks that contribute directly to meeting the deadlines for commanding the rover s each sol (1 sol = 1 Martian day) - achieving a turnaround time of 18 hours or less, while facilitating strategic team interactions with other organizations that do not work on a Mars time schedule.

A Rover Mobility Platform with Autonomous Capability to Enable Mars Sample Return

Science.gov (United States)

Fulford, P.; Langley, C.; Shaw, A.

2018-04-01

The next step in understanding Mars is sample return. In Fall 2016, the CSA conducted an analogue deployment using the Mars Exploration Science Rover. An objective was to demonstrate the maturity of the rover's guidance, navigation, and control.

Soft-Robotic Rover with Electrodynamic Power Scavenging

Data.gov (United States)

National Aeronautics and Space Administration — We propose a rover architecture for Europa and other planetary environments where soft robotics enables scientific investigation or human-precursor missions that...

Two-phase flow boiling pressure drop in small channels

International Nuclear Information System (INIS)

Sardeshpande, Madhavi V.; Shastri, Parikshit; Ranade, Vivek V.

2016-01-01

Highlights: • Study of typical 19 mm steam generator tube has been undertaken in detail. • Study of two phase flow boiling pressure drop, flow instability and identification of flow regimes using pressure fluctuations is the main focus of present work. • Effect of heat and mass flux on pressure drop and void fraction was studied. • Flow regimes identified from pressure fluctuations data using FFT plots. • Homogeneous model predicted pressure drop well in agreement. - Abstract: Two-phase flow boiling in small channels finds a variety of applications in power and process industries. Heat transfer, boiling flow regimes, flow instabilities, pressure drop and dry out are some of the key issues related to two-phase flow boiling in channels. In this work, the focus is on pressure drop in two-phase flow boiling in tubes of 19 mm diameter. These tubes are typically used in steam generators. Relatively limited experimental database is available on 19 mm ID tube. Therefore, in the present work, the experimental set-up is designed for studying flow boiling in 19 mm ID tube in such a way that any of the different flow regimes occurring in a steam generator tube (from pre-heating of sub-cooled water to dry-out) can be investigated by varying inlet conditions. The reported results cover a reasonable range of heat and mass flux conditions such as 9–27 kW/m 2 and 2.9–5.9 kg/m 2 s respectively. In this paper, various existing correlations are assessed against experimental data for the pressure drop in a single, vertical channel during flow boiling of water at near-atmospheric pressure. A special feature of these experiments is that time-dependent pressures are measured at four locations along the channel. The steady-state pressure drop is estimated and the identification of boiling flow regimes is done with transient characteristics using time series analysis. Experimental data and corresponding results are compared with the reported correlations. The results will be

A Four-Wheel-Rhombus-Arranged Mobility System for a New Lunar Robotic Rover

Directory of Open Access Journals (Sweden)

Guilin Wen

2013-10-01

Full Text Available Different from traditional ground vehicles, planetary robotic rovers with limited weight and power need to travel in unfamiliar and extremely arduous environments. In this paper, a newly developed four-wheel-rhombus-arranged (FWRA mobility system is presented as a lunar robotic rover with high mobility and a low-weight structure. The mobility system integrates independent active suspensions with a passive rotary link structure. The active suspension with swing arms improves the rover's capacity to escape from a trapped environment whereas the passive rotary link structure guarantees continuous contact between the four wheels and the terrain. The four-wheel-three-axis rhombus configuration of the mobility system gives a high degree of lightweight structure because it has a simple mechanism with the minimum number of wheels among wheeled rovers with three-axis off-road mobility. The performance evaluation of the lightweight nature of the structure, manoeuvrability and the mobility required in a planetary exploring environment are illustrated by theoretical analysis and partly shown by experiments on the developed rover prototype.

Status of advanced small pressurized water reactors

International Nuclear Information System (INIS)

Chen Peipei; Zhou Yun

2012-01-01

In order to expand the nuclear power in energy and desalination, increase competitiveness in global nuclear power market, many developed countries with strong nuclear energy technology have realized the importance of Small Modular Reactor (SMR) and initiated heavy R and D programs in SMR. The Advanced Small Pressurized Water Reactor (ASPWR) is characterized by great advantages in safety and economy and can be used in remote power grid and replace mid/small size fossil plant economically. This paper reviews the history and current status of SMR and ASPWR, and also discusses the design concept, safety features and other advantages of ASPWR. The purpose of this paper is to provide an overall review of ASPWR technology in western countries, and to promote the R and D in ASPWR in China. (authors)

Onboard autonomous mineral detectors for Mars rovers

Science.gov (United States)

Gilmore, M. S.; Bornstein, B.; Castano, R.; Merrill, M.; Greenwood, J.

2005-12-01

Mars rovers and orbiters currently collect far more data than can be downlinked to Earth, which reduces mission science return; this problem will be exacerbated by future rovers of enhanced capabilities and lifetimes. We are developing onboard intelligence sufficient to extract geologically meaningful data from spectrometer measurements of soil and rock samples, and thus to guide the selection, measurement and return of these data from significant targets at Mars. Here we report on techniques to construct mineral detectors capable of running on current and future rover and orbital hardware. We focus on carbonate and sulfate minerals which are of particular geologic importance because they can signal the presence of water and possibly life. Sulfates have also been discovered at the Eagle and Endurance craters in Meridiani Planum by the Mars Exploration Rover (MER) Opportunity and at other regions on Mars by the OMEGA instrument aboard Mars Express. We have developed highly accurate artificial neural network (ANN) and Support Vector Machine (SVM) based detectors capable of identifying calcite (CaCO3) and jarosite (KFe3(SO4)2(OH)6) in the visible/NIR (350-2500 nm) spectra of both laboratory specimens and rocks in Mars analogue field environments. To train the detectors, we used a generative model to create 1000s of linear mixtures of library end-member spectra in geologically realistic percentages. We have also augmented the model to include nonlinear mixing based on Hapke's models of bidirectional reflectance spectroscopy. Both detectors perform well on the spectra of real rocks that contain intimate mixtures of minerals, rocks in natural field environments, calcite covered by Mars analogue dust, and AVIRIS hyperspectral cubes. We will discuss the comparison of ANN and SVM classifiers for this task, technical challenges (weathering rinds, atmospheric compositions, and computational complexity), and plans for integration of these detectors into both the Coupled Layer

What Can the Curiosity Rover Tell Us About the Climate of Mars?

Science.gov (United States)

Haberle, Robert M.

2013-01-01

What Can the Curiosity Rover Tell Us About the Climate of Mars? Assessing the habitability of Gale Crater is the goal of the Curiosity Rover, which has been gathering data since landing on the Red Planet last August. To meet that goal, Curiosity brought with it a suite of instruments to measure the biological potential of the landing site, the geology and chemistry of its surface, and local environmental conditions. Some of these instruments illuminate the nature of the planet fs atmosphere and climate system, both for present day conditions as well as for conditions that existed billions of years ago. For present day conditions, Curiosity has a standard meteorology package that measures pressure, temperature, winds and humidity, plus a sensor the measures the UV flux. These data confirm what we learned from previous missions namely that today Mars is a cold, dry, and barren desert-like planet. For past conditions, however, wetter and probably warmer conditions are indicated. Curiosities cameras reveal gravel beds that must have formed by flowing rivers, and sedimentary deposits of layered sand and mudstones possibly associated with lakes. An ancient aqueous environment is further supported by the presence of sulfate veins coursing through some of the rocks in Yellowknife Bay where Curiosity is planning its first drilling activity. I will discuss these results and their implications in this lecture.

Measuring Soil Moisture in Skeletal Soils Using a COSMOS Rover

Science.gov (United States)

Medina, C.; Neely, H.; Desilets, D.; Mohanty, B.; Moore, G. W.

2017-12-01

The presence of coarse fragments directly influences the volumetric water content of the soil. Current surface soil moisture sensors often do not account for the presence of coarse fragments, and little research has been done to calibrate these sensors under such conditions. The cosmic-ray soil moisture observation system (COSMOS) rover is a passive, non-invasive surface soil moisture sensor with a footprint greater than 100 m. Despite its potential, the COSMOS rover has yet to be validated in skeletal soils. The goal of this study was to validate measurements of surface soil moisture as taken by a COSMOS rover on a Texas skeletal soil. Data was collected for two soils, a Marfla clay loam and Chinati-Boracho-Berrend association, in West Texas. Three levels of data were collected: 1) COSMOS surveys at three different soil moistures, 2) electrical conductivity surveys within those COSMOS surveys, and 3) ground-truth measurements. Surveys with the COSMOS rover covered an 8000-h area and were taken both after large rain events (>2") and a long dry period. Within the COSMOS surveys, the EM38-MK2 was used to estimate the spatial distribution of coarse fragments in the soil around two COSMOS points. Ground truth measurements included coarse fragment mass and volume, bulk density, and water content at 3 locations within each EM38 survey. Ground-truth measurements were weighted using EM38 data, and COSMOS measurements were validated by their distance from the samples. There was a decrease in water content as the percent volume of coarse fragment increased. COSMOS estimations responded to both changes in coarse fragment percent volume and the ground-truth volumetric water content. Further research will focus on creating digital soil maps using landform data and water content estimations from the COSMOS rover.

Using Wind Driven Tumbleweed Rovers to Explore Martian Gully Features

Science.gov (United States)

Antol, Jeffrey; Woodard, Stanley E.; Hajos, Gregory A.; Heldmann, Jennifer L.; Taylor, Bryant D.

2005-01-01

Gully features have been observed on the slopes of numerous Martian crater walls, valleys, pits, and graben. Several mechanisms for gully formation have been proposed, including: liquid water aquifers (shallow and deep), melting ground ice, snow melt, CO2 aquifers, and dry debris flow. Remote sensing observations indicate that the most likely erosional agent is liquid water. Debate concerns the source of this water. Observations favor a liquid water aquifer as the primary candidate. The current strategy in the search for life on Mars is to "follow the water." A new vehicle known as a Tumbleweed rover may be able to conduct in-situ investigations in the gullies, which are currently inaccessible by conventional rovers. Deriving mobility through use of the surface winds on Mars, Tumbleweed rovers would be lightweight and relatively inexpensive thus allowing multiple rovers to be deployed in a single mission to survey areas for future exploration. NASA Langley Research Center (LaRC) is developing deployable structure Tumbleweed concepts. An extremely lightweight measurement acquisition system and sensors are proposed for the Tumbleweed rover that greatly increases the number of measurements performed while having negligible mass increase. The key to this method is the use of magnetic field response sensors designed as passive inductor-capacitor circuits that produce magnetic field responses whose attributes correspond to values of physical properties for which the sensors measure. The sensors do not need a physical connection to a power source or to data acquisition equipment resulting in additional weight reduction. Many of the sensors and interrogating antennae can be directly placed on the Tumbleweed using film deposition methods such as photolithography thus providing further weight reduction. Concepts are presented herein for methods to measure subsurface water, subsurface metals, planetary winds and environmental gases.

Laser-powered Martian rover

Science.gov (United States)

Harries, W. L.; Meador, W. E.; Miner, G. A.; Schuster, Gregory L.; Walker, G. H.; Williams, M. D.

1989-01-01

Two rover concepts were considered: an unpressurized skeleton vehicle having available 4.5 kW of electrical power and limited to a range of about 10 km from a temporary Martian base and a much larger surface exploration vehicle (SEV) operating on a maximum 75-kW power level and essentially unrestricted in range or mission. The only baseline reference system was a battery-operated skeleton vehicle with very limited mission capability and range and which would repeatedly return to its temporary base for battery recharging. It was quickly concluded that laser powering would be an uneconomical overkill for this concept. The SEV, on the other hand, is a new rover concept that is especially suited for powering by orbiting solar or electrically pumped lasers. Such vehicles are visualized as mobile habitats with full life-support systems onboard, having unlimited range over the Martian surface, and having extensive mission capability (e.g., core drilling and sampling, construction of shelters for protection from solar flares and dust storms, etc.). Laser power beaming to SEV's was shown to have the following advantages: (1) continuous energy supply by three orbiting lasers at 2000 km (no storage requirements as during Martian night with direct solar powering); (2) long-term supply without replacement; (3) very high power available (MW level possible); and (4) greatly enhanced mission enabling capability beyond anything currently conceived.

INVESTINGATION DOWNWARD WIND PRESSURE ON A SMALL QUADROTOR HELICOPTER

OpenAIRE

RAHMATI, Sadegh; GHASED, Amir

2015-01-01

Abstract. Small rotary-wing UAVs are susceptible to gusts and other environmental disturbances that affect inflow at their rotors. Inflow variations cause unexpected aerodynamic forces through changes in thrust conditions and unmodeled blade-flapping dynamics. This pa­per introduces an onboard, pressure-based flow measurement system developed for a small quadrotor helicopter. The probe-based instrumentation package provides spatially dis­tributed airspeed measurements along each of the aircra...

The Mars Astrobiology Explorer-Cacher (MAX-C): a potential rover mission for 2018. Final report of the Mars Mid-Range Rover Science Analysis Group (MRR-SAG) October 14, 2009.

Science.gov (United States)

2010-03-01

This report documents the work of the Mid-Range Rover Science Analysis Group (MRR-SAG), which was assigned to formulate a concept for a potential rover mission that could be launched to Mars in 2018. Based on programmatic and engineering considerations as of April 2009, our deliberations assumed that the potential mission would use the Mars Science Laboratory (MSL) sky-crane landing system and include a single solar-powered rover. The mission would also have a targeting accuracy of approximately 7 km (semimajor axis landing ellipse), a mobility range of at least 10 km, and a lifetime on the martian surface of at least 1 Earth year. An additional key consideration, given recently declining budgets and cost growth issues with MSL, is that the proposed rover must have lower cost and cost risk than those of MSL--this is an essential consideration for the Mars Exploration Program Analysis Group (MEPAG). The MRR-SAG was asked to formulate a mission concept that would address two general objectives: (1) conduct high priority in situ science and (2) make concrete steps toward the potential return of samples to Earth. The proposed means of achieving these two goals while balancing the trade-offs between them are described here in detail. We propose the name Mars Astrobiology Explorer-Cacher(MAX-C) to reflect the dual purpose of this potential 2018 rover mission.

Ambler - An autonomous rover for planetary exploration

Science.gov (United States)

Bares, John; Hebert, Martial; Kanade, Takeo; Krotkov, Eric; Mitchell, Tom

1989-01-01

The authors are building a prototype legged rover, called the Ambler (loosely an acronym for autonomous mobile exploration robot) and testing it on full-scale, rugged terrain of the sort that might be encountered on the Martian surface. They present an overview of their research program, focusing on locomotion, perception, planning, and control. They summarize some of the most important goals and requirements of a rover design and describe how locomotion, perception, and planning systems can satisfy these requirements. Since the program is relatively young (one year old at the time of writing) they identify issues and approaches and describe work in progress rather than report results. It is expected that many of the technologies developed will be applicable to other planetary bodies and to terrestrial concerns such as hazardous waste assessment and remediation, ocean floor exploration, and mining.

Pancam and microscopic imager observations of dust on the Spirit Rovers

DEFF Research Database (Denmark)

Vaughan....[], Alicia F.; Johnson, Jeffrey R.; Walter, Goetz

2010-01-01

This work describes dust deposits on the Spirit Rover over 2000 sols through examination of Pancam and Microscopic Imager observations of specific locations on the rover body, including portions of the solar array, Pancam and Mini-TES calibration targets, and the magnets. This data set reveals...... the three "cleaning events" experienced by Spirit to date, the spectral properties of dust, and the tendency of dust particles to form aggregates 100 um and larger...

Researches on hazard avoidance cameras calibration of Lunar Rover

Science.gov (United States)

Li, Chunyan; Wang, Li; Lu, Xin; Chen, Jihua; Fan, Shenghong

2017-11-01

Lunar Lander and Rover of China will be launched in 2013. It will finish the mission targets of lunar soft landing and patrol exploration. Lunar Rover has forward facing stereo camera pair (Hazcams) for hazard avoidance. Hazcams calibration is essential for stereo vision. The Hazcam optics are f-theta fish-eye lenses with a 120°×120° horizontal/vertical field of view (FOV) and a 170° diagonal FOV. They introduce significant distortion in images and the acquired images are quite warped, which makes conventional camera calibration algorithms no longer work well. A photogrammetric calibration method of geometric model for the type of optical fish-eye constructions is investigated in this paper. In the method, Hazcams model is represented by collinearity equations with interior orientation and exterior orientation parameters [1] [2]. For high-precision applications, the accurate calibration model is formulated with the radial symmetric distortion and the decentering distortion as well as parameters to model affinity and shear based on the fisheye deformation model [3] [4]. The proposed method has been applied to the stereo camera calibration system for Lunar Rover.

Mars Exploration Rovers Propulsive Maneuver Design

Science.gov (United States)

Potts, Christopher L.; Raofi, Behzad; Kangas, Julie A.

2004-01-01

The Mars Exploration Rovers Spirit and Opportunity successfully landed respectively at Gusev Crater and Meridiani Planum in January 2004. The rovers are essentially robotic geologists, sent on a mission to search for evidence in the rocks and soil pertaining to the historical presence of water and the ability to possibly sustain life. In order to conduct NASA's 'follow the water' strategy on opposite sides of the planet Mars, an interplanetary journey of over 300 million miles culminated with historic navigation precision. Rigorous trajectory targeting and control was necessary to achieve the atmospheric entry requirements for the selected landing sites. The propulsive maneuver design challenge was to meet or exceed these requirements while preserving the necessary design margin to accommodate additional project concerns. Landing site flexibility was maintained for both missions after launch, and even after the first trajectory correction maneuver for Spirit. The final targeting strategy was modified to improve delivery performance and reduce risk after revealing constraining trajectory control characteristics. Flight results are examined and summarized for the six trajectory correction maneuvers that were planned for each mission.

A Polar Rover for Large-Scale Scientific Surveys: Design, Implementation and Field Test Results

Directory of Open Access Journals (Sweden)

Yuqing He

2015-10-01

Full Text Available Exploration of polar regions is of great importance to scientific research. Unfortunately, due to the harsh environment, most of the regions on the Antarctic continent are still unreachable for humankind. Therefore, in 2011, the Chinese National Antarctic Research Expedition (CHINARE launched a project to design a rover to conduct large-scale scientific surveys on the Antarctic. The main challenges for the rover are twofold: one is the mobility, i.e., how to make a rover that could survive the harsh environment and safely move on the uneven, icy and snowy terrain; the other is the autonomy, in that the robot should be able to move at a relatively high speed with little or no human intervention so that it can explore a large region in a limit time interval under the communication constraints. In this paper, the corresponding techniques, especially the polar rover's design and autonomous navigation algorithms, are introduced in detail. Subsequently, an experimental report of the fields tests on the Antarctic is given to show some preliminary evaluation of the rover. Finally, experiences and existing challenging problems are summarized.

The Preparation for and Execution of Engineering Operations for the Mars Curiosity Rover Mission

Science.gov (United States)

Samuels, Jessica A.

2013-01-01

The Mars Science Laboratory Curiosity Rover mission is the most complex and scientifically packed rover that has ever been operated on the surface of Mars. The preparation leading up to the surface mission involved various tests, contingency planning and integration of plans between various teams and scientists for determining how operation of the spacecraft (s/c) would be facilitated. In addition, a focused set of initial set of health checks needed to be defined and created in order to ensure successful operation of rover subsystems before embarking on a two year science journey. This paper will define the role and responsibilities of the Engineering Operations team, the process involved in preparing the team for rover surface operations, the predefined engineering activities performed during the early portion of the mission, and the evaluation process used for initial and day to day spacecraft operational assessment.

Antibodies under pressure: A Small-Angle X-ray Scattering study of Immunoglobulin G under high hydrostatic pressure.

Science.gov (United States)

König, Nico; Paulus, Michael; Julius, Karin; Schulze, Julian; Voetz, Matthias; Tolan, Metin

2017-12-01

In the present work two subclasses of the human antibody Immunoglobulin G (IgG) have been investigated by Small-Angle X-ray Scattering under high hydrostatic pressures up to 5kbar. It is shown that IgG adopts a symmetric T-shape in solution which differs significantly from available crystal structures. Moreover, high-pressure experiments verify the high stability of the IgG molecule. It is not unfolded by hydrostatic pressures of up to 5kbar but a slight increase of the radius of gyration was observed at elevated pressures. Copyright © 2017 Elsevier B.V. All rights reserved.

Fast Optical Hazard Detection for Planetary Rovers Using Multiple Spot Laser Triangulation

Science.gov (United States)

Matthies, L.; Balch, T.; Wilcox, B.

1997-01-01

A new laser-based optical sensor system that provides hazard detection for planetary rovers is presented. It is anticipated that the sensor can support safe travel at speeds up to 6cm/second for large (1m) rovers in full sunlight on Earth or Mars. The system overcomes limitations in an older design that require image differencing ot detect a laser stripe in full sun.

Real-Time Science Operations to Support a Lunar Polar Volatiles Rover Mission

Science.gov (United States)

Heldmann, Jennifer L.; Colaprete, Anthony; Elphic, Richard C.; Mattes, Greg; Ennico, Kimberly; Fritzler, Erin; Marinova, Margarita M.; McMurray, Robert; Morse, Stephanie; Roush, Ted L.;

A vision system for a Mars rover

Science.gov (United States)

Wilcox, Brian H.; Gennery, Donald B.; Mishkin, Andrew H.; Cooper, Brian K.; Lawton, Teri B.; Lay, N. Keith; Katzmann, Steven P.

1988-01-01

A Mars rover must be able to sense its local environment with sufficient resolution and accuracy to avoid local obstacles and hazards while moving a significant distance each day. Power efficiency and reliability are extremely important considerations, making stereo correlation an attractive method of range sensing compared to laser scanning, if the computational load and correspondence errors can be handled. Techniques for treatment of these problems, including the use of more than two cameras to reduce correspondence errors and possibly to limit the computational burden of stereo processing, have been tested at JPL. Once a reliable range map is obtained, it must be transformed to a plan view and compared to a stored terrain database, in order to refine the estimated position of the rover and to improve the database. The slope and roughness of each terrain region are computed, which form the basis for a traversability map allowing local path planning. Ongoing research and field testing of such a system is described.

Control of positive end-expiratory pressure (PEEP for small animal ventilators

Directory of Open Access Journals (Sweden)

Leão Nunes Marcelo V

2010-07-01

Full Text Available Abstract Background The positive end-expiratory pressure (PEEP for the mechanical ventilation of small animals is frequently obtained with water seals or by using ventilators developed for human use. An alternative mechanism is the use of an on-off expiratory valve closing at the moment when the alveolar pressure is equal to the target PEEP. In this paper, a novel PEEP controller (PEEP-new and the PEEP system of a commercial small-animal ventilator, both based on switching an on-off valve, are evaluated. Methods The proposed PEEP controller is a discrete integrator monitoring the error between the target PEEP and the airways opening pressure prior to the onset of an inspiratory cycle. In vitro as well as in vivo experiments with rats were carried out and the PEEP accuracy, settling time and under/overshoot were considered as a measure of performance. Results The commercial PEEP controller did not pass the tests since it ignores the airways resistive pressure drop, resulting in a PEEP 5 cmH2O greater than the target in most conditions. The PEEP-new presented steady-state errors smaller than 0.5 cmH2O, with settling times below 10 s and under/overshoot smaller than 2 cmH2O. Conclusion The PEEP-new presented acceptable performance, considering accuracy and temporal response. This novel PEEP generator may prove useful in many applications for small animal ventilators.

Microbiological cleanliness of the Mars Exploration Rover spacecraft

Science.gov (United States)

Newlin, L.; Barengoltz, J.; Chung, S.; Kirschner, L.; Koukol, R.; Morales, F.

2002-01-01

Planetary protection for Mars missions is described, and the approach being taken by the Mars Exploration Rover Project is discussed. Specific topics include alcohol wiping, dry heat microbial reduction, microbiological assays, and the Kennedy Space center's PHSF clean room.

Assessment of a small pressurized water reactor for industrial energy

International Nuclear Information System (INIS)

Klepper, O.H.; Fuller, L.C.; Myers, M.L.

1977-01-01

An evaluation of several recent ERDA/ORNL sponsored studies on the application of a small, 365 MW(t) pressurized water reactor for industrial energy is presented. Preliminary studies have investigated technical and reliability requirements; costs for nuclear and fossil based steam were compared, including consideration of economic inflation and financing methods. For base-load industrial steam production, small reactors appear economically attractive relative to coal fired boilers that use coal priced at $30/ton

Mission-directed path planning for planetary rover exploration

Science.gov (United States)

Tompkins, Paul

2005-07-01

Robotic rovers uniquely benefit planetary exploration---they enable regional exploration with the precision of in-situ measurements, a combination impossible from an orbiting spacecraft or fixed lander. Mission planning for planetary rover exploration currently utilizes sophisticated software for activity planning and scheduling, but simplified path planning and execution approaches tailored for localized operations to individual targets. This approach is insufficient for the investigation of multiple, regionally distributed targets in a single command cycle. Path planning tailored for this task must consider the impact of large scale terrain on power, speed and regional access; the effect of route timing on resource availability; the limitations of finite resource capacity and other operational constraints on vehicle range and timing; and the mutual influence between traverses and upstream and downstream stationary activities. Encapsulating this reasoning in an efficient autonomous planner would allow a rover to continue operating rationally despite significant deviations from an initial plan. This research presents mission-directed path planning that enables an autonomous, strategic reasoning capability for robotic explorers. Planning operates in a space of position, time and energy. Unlike previous hierarchical approaches, it treats these dimensions simultaneously to enable globally-optimal solutions. The approach calls on a near incremental search algorithm designed for planning and re-planning under global constraints, in spaces of higher than two dimensions. Solutions under this method specify routes that avoid terrain obstacles, optimize the collection and use of rechargable energy, satisfy local and global mission constraints, and account for the time and energy of interleaved mission activities. Furthermore, the approach efficiently re-plans in response to updates in vehicle state and world models, and is well suited to online operation aboard a robot

RAT magnet experiment on the Mars Exploration Rovers: Spirit and Opportunity beyond sol 500

DEFF Research Database (Denmark)

Leer, Kristoffer; Goetz, Walter; Chan, Marjorie A.

2011-01-01

The Rock Abrasion Tool (RAT) magnet experiment on the Mars Exploration Rovers was designed to collect dust from rocks ground by the RAT of the two rovers on the surface of Mars. The dust collected on the magnets is now a mixture of dust from many grindings. Here the new data from the experiment...

Lunar ground penetrating radar: Minimizing potential data artifacts caused by signal interaction with a rover body

Science.gov (United States)

Angelopoulos, Michael; Redman, David; Pollard, Wayne H.; Haltigin, Timothy W.; Dietrich, Peter

2014-11-01

Ground-penetrating radar (GPR) is the leading geophysical candidate technology for future lunar missions aimed at mapping shallow stratigraphy (lunar materials, as well as its small size and lightweight components, make it a very attractive option from both a scientific and engineering perspective. However, the interaction between a GPR signal and the rover body is poorly understood and must be investigated prior to a space mission. In doing so, engineering and survey design strategies should be developed to enhance GPR performance in the context of the scientific question being asked. This paper explores the effects of a rover (simulated with a vertical metal plate) on GPR results for a range of heights above the surface and antenna configurations at two sites: (i) a standard GPR testing site with targets of known position, size, and material properties, and; (ii) a frozen lake for surface reflectivity experiments. Our results demonstrate that the GPR antenna configuration is a key variable dictating instrument design, with the XX polarization considered optimal for minimizing data artifact generation. These findings could thus be used to help guide design requirements for an eventual flight instrument.

The Curiosity Mars Rover's Fault Protection Engine

Science.gov (United States)

Benowitz, Ed

2014-01-01

The Curiosity Rover, currently operating on Mars, contains flight software onboard to autonomously handle aspects of system fault protection. Over 1000 monitors and 39 responses are present in the flight software. Orchestrating these behaviors is the flight software's fault protection engine. In this paper, we discuss the engine's design, responsibilities, and present some lessons learned for future missions.

Measuring planetary field parameters by scattered "SSSS" from the Husar-5 Rover

Science.gov (United States)

Lang, A.; Kocsis, A.; Balaskó, D.; Csóka, B.; Molnar, B.; Sztojka, A.; Bejó, M.; Joób, Z.

2017-09-01

HUSAR-5 Rover reloaded: 2 years ago the Hunveyor-Husar Team in our school made yet a similar project. The ground idea was, we try to keep step with the main trends in the space research, in our recent case with the so called MSSM (Micro Sized Space- Mothership) and NPSDR (Nano, Pico Space Devices and Robots). [1]Of course, we do not want to scatter the smaller probe-cubes from a mothership, but from the Husar rover, and to do it on the planetary surface after landing. We have fabricated the rover with the ejecting tower and we have shown it on the EPSC 2015.The word "reloaded" means not only a new shape of the bullets, but a new mission with a new team. There are more pupils working in this project. The new bullets "SSSS" will be printed by a 3D printer.The microcontroller in bullets can be programmed with Arduino, so the "new generation" is able to do it.

a Performance Comparison of Feature Detectors for Planetary Rover Mapping and Localization

Science.gov (United States)

Wan, W.; Peng, M.; Xing, Y.; Wang, Y.; Liu, Z.; Di, K.; Teng, B.; Mao, X.; Zhao, Q.; Xin, X.; Jia, M.

2017-07-01

Feature detection and matching are key techniques in computer vision and robotics, and have been successfully implemented in many fields. So far there is no performance comparison of feature detectors and matching methods for planetary mapping and rover localization using rover stereo images. In this research, we present a comprehensive evaluation and comparison of six feature detectors, including Moravec, Förstner, Harris, FAST, SIFT and SURF, aiming for optimal implementation of feature-based matching in planetary surface environment. To facilitate quantitative analysis, a series of evaluation criteria, including distribution evenness of matched points, coverage of detected points, and feature matching accuracy, are developed in the research. In order to perform exhaustive evaluation, stereo images, simulated under different baseline, pitch angle, and interval of adjacent rover locations, are taken as experimental data source. The comparison results show that SIFT offers the best overall performance, especially it is less sensitive to changes of image taken at adjacent locations.

A PERFORMANCE COMPARISON OF FEATURE DETECTORS FOR PLANETARY ROVER MAPPING AND LOCALIZATION

Directory of Open Access Journals (Sweden)

W. Wan

2017-07-01

Full Text Available Feature detection and matching are key techniques in computer vision and robotics, and have been successfully implemented in many fields. So far there is no performance comparison of feature detectors and matching methods for planetary mapping and rover localization using rover stereo images. In this research, we present a comprehensive evaluation and comparison of six feature detectors, including Moravec, Förstner, Harris, FAST, SIFT and SURF, aiming for optimal implementation of feature-based matching in planetary surface environment. To facilitate quantitative analysis, a series of evaluation criteria, including distribution evenness of matched points, coverage of detected points, and feature matching accuracy, are developed in the research. In order to perform exhaustive evaluation, stereo images, simulated under different baseline, pitch angle, and interval of adjacent rover locations, are taken as experimental data source. The comparison results show that SIFT offers the best overall performance, especially it is less sensitive to changes of image taken at adjacent locations.

The Athena Science Payload for the 2003 Mars Exploration Rovers

Science.gov (United States)

Squyres, S. W.; Arvidson, R. E.; Bell, J. F., III; Carr, M.; Christensen, P.; DesMarais, D.; Economou, T.; Gorevan, S.; Haskin, L.; Herkenhoff, K.

2001-01-01

The Athena Mars rover payload is a suite of scientific instruments and tools for geologic exploration of the martian surface. It is designed to: (1) Provide color stereo imaging of martian surface environments, and remotely-sensed point discrimination of mineralogical composition. (2) Determine the elemental and mineralogical composition of martian surface materials, including soils, rock surfaces, and rock interiors. (3) Determine the fine-scale textural properties of these materials. Two identical copies of the Athena payload will be flown in 2003 on the two Mars Exploration Rovers. The payload is at a high state of maturity, and first copies of several of the instruments have already been built and tested for flight.

Characterization of small intestinal pressure waves in ambulant subjects recorded with a novel portable manometric system

NARCIS (Netherlands)

Samsom, M.; Fraser, R.; Smout, A. J.; Verhagen, M. A.; Adachi, K.; Horowitz, M.; Dent, J.

1999-01-01

The organization of lumen-occlusive pressure waves is believed to be an important determinant of luminal flow. At present, little is known about the organization of small intestinal pressure waves in humans. The aim of the present study was to characterize the spatiotemporal organization of small

Infrared Spectrometer for ExoMars: A Mast-Mounted Instrument for the Rover

Science.gov (United States)

Korablev, Oleg I.; Dobrolensky, Yurii; Evdokimova, Nadezhda; Fedorova, Anna A.; Kuzmin, Ruslan O.; Mantsevich, Sergei N.; Cloutis, Edward A.; Carter, John; Poulet, Francois; Flahaut, Jessica; Griffiths, Andrew; Gunn, Matthew; Schmitz, Nicole; Martín-Torres, Javier; Zorzano, Maria-Paz; Rodionov, Daniil S.; Vago, Jorge L.; Stepanov, Alexander V.; Titov, Andrei Yu.; Vyazovetsky, Nikita A.; Trokhimovskiy, Alexander Yu.; Sapgir, Alexander G.; Kalinnikov, Yurii K.; Ivanov, Yurii S.; Shapkin, Alexei A.; Ivanov, Andrei Yu.

2017-07-01

ISEM (Infrared Spectrometer for ExoMars) is a pencil-beam infrared spectrometer that will measure reflected solar radiation in the near infrared range for context assessment of the surface mineralogy in the vicinity of the ExoMars rover. The instrument will be accommodated on the mast of the rover and will be operated together with the panoramic camera (PanCam), high-resolution camera (HRC). ISEM will study the mineralogical and petrographic composition of the martian surface in the vicinity of the rover, and in combination with the other remote sensing instruments, it will aid in the selection of potential targets for close-up investigations and drilling sites. Of particular scientific interest are water-bearing minerals, such as phyllosilicates, sulfates, carbonates, and minerals indicative of astrobiological potential, such as borates, nitrates, and ammonium-bearing minerals. The instrument has an ˜1° field of view and covers the spectral range between 1.15 and 3.30 μm with a spectral resolution varying from 3.3 nm at 1.15 μm to 28 nm at 3.30 μm. The ISEM optical head is mounted on the mast, and its electronics box is located inside the rover's body. The spectrometer uses an acousto-optic tunable filter and a Peltier-cooled InAs detector. The mass of ISEM is 1.74 kg, including the electronics and harness. The science objectives of the experiment, the instrument design, and operational scenarios are described.

Autonomous navigation and mobility for a planetary rover

Science.gov (United States)

Miller, David P.; Mishkin, Andrew H.; Lambert, Kenneth E.; Bickler, Donald; Bernard, Douglas E.

1989-01-01

This paper presents an overview of the onboard subsystems that will be used in guiding a planetary rover. Particular emphasis is placed on the planning and sensing systems and their associated costs, particularly in computation. Issues that will be used in evaluating trades between the navigation system and mobility system are also presented.

Automation Rover for Extreme Environments

Science.gov (United States)

Sauder, Jonathan; Hilgemann, Evan; Johnson, Michael; Parness, Aaron; Hall, Jeffrey; Kawata, Jessie; Stack, Kathryn

2017-01-01

Almost 2,300 years ago the ancient Greeks built the Antikythera automaton. This purely mechanical computer accurately predicted past and future astronomical events long before electronics existed1. Automata have been credibly used for hundreds of years as computers, art pieces, and clocks. However, in the past several decades automata have become less popular as the capabilities of electronics increased, leaving them an unexplored solution for robotic spacecraft. The Automaton Rover for Extreme Environments (AREE) proposes an exciting paradigm shift from electronics to a fully mechanical system, enabling longitudinal exploration of the most extreme environments within the solar system.

NASA Curiosity rover hits organic pay dirt on Mars

Science.gov (United States)

Voosen, Paul

2018-06-01

Since NASA's Curiosity rover landed on Mars in 2012, it has sifted samples of soil and ground-up rock for signs of organic molecules—the complex carbon chains that on Earth form the building blocks of life. Past detections have been so faint that they could be just contamination. Now, samples taken from two different drill sites on an ancient lakebed have yielded complex organic macromolecules that look strikingly similar to kerogen, the goopy fossilized building blocks of oil and gas on Earth. At a few dozen parts per million, the detected levels are 100 times higher than previous finds, but scientists still cannot say whether they have origins in biology or geology. The discovery positions scientists to begin searching for direct evidence of past life on Mars and bolsters the case for returning rock samples from the planet, an effort that begins with the Mars 2020 rover.

A New Capability for Automated Target Selection and Sampling for use with Remote Sensing Instruments on the MER Rovers

Science.gov (United States)

Castano, R.; Estlin, T.; Anderson, R. C.; Gaines, D.; Bornstein, B.; de Granville, C.; Tang, B.; Thompson, D.; Judd, M.

2008-12-01

The Onboard Autonomous Science Investigation System (OASIS) evaluates geologic data gathered by a planetary rover. The system is designed to operate onboard a rover identifying and reacting to serendipitous science opportunities, such as rocks with novel properties. OASIS operates by analyzing data the rover gathers, and then using machine learning techniques, prioritizing the data based on criteria set by the science team. This prioritization can be used to organize data for transmission back to Earth and it can be used to search for specific targets it has been told to find by the science team. If one of these targets is found, it is identified as a new science opportunity and a "science alert" is sent to a planning and scheduling system. After reviewing the rover's current operational status to ensure that it has enough resources to complete its traverse and act on the new science opportunity, OASIS can change the command sequence of the rover in order to obtain additional science measurements. Currently, OASIS is being applied on a new front. OASIS is providing a new rover mission technology that enables targeted remote-sensing science in an automated fashion during or after rover traverses. Currently, targets for remote sensing instruments, especially narrow field-of-view instruments (such as the MER Mini- TES spectrometer or the 2009 MSL ChemCam spectrometer) must be selected manually based on imagery already on the ground with the operations team. OASIS will enable the rover flight software to analyze imagery onboard in order to autonomously select and sequence targeted remote-sensing observations in an opportunistic fashion. We are in the process of scheduling an onboard MER experiment to demonstrate the OASIS capability in early 2009.

APXS on board Chandrayaan-2 Rover

Science.gov (United States)

Shanmugam, M.; Sripada, V. S. Murty; Acharya, Y. B.; Goyal, S. K.

2012-07-01

Alpha Particle X-ray Spectrometer (APXS) is a well proven instrument for quantitative in situ elemental analysis of the planetary surfaces and has been successfully employed for Mars surface exploration. Chandrayaan-2, ISRO's second lunar mission having an Orbiter, Lander and Rover has provided an opportunity to explore the lunar surface with superior detectors such as Silicon Drift Detector (SDD) with energy resolution of about 150eV @ 5.9keV. The objective of the APXS instrument is to analyse several soil/rock samples along the rover traverse for the major elements with characteristic X-rays in 1 to 25keV range. The working principle of APXS involves measuring the intensity of characteristic X-rays emitted from the sample due to Alpha Particle Induced X-ray Emission (PIXE) and X-ray florescence (XRF) processes using suitable radioactive sources, allowing the determination of elements from Na to Br, spanning the energy range of 0.9 to 16keV. For this experiment ^{244}Cm radioactive source has been chosen which emits both Alpha particles (5.8MeV) and X-rays (14.1keV, 18keV). APXS uses six Alpha sources, each about 5mCi activity. Unlike Mars, lunar environment poses additional challenges due to the regolith and extreme surface temperature changes, to operate the APXS. Our APXS instrument consists of two packages namely APXS sensor head and APXS signal electronics. The sensor head assembly contains SDD, six alpha sources and front end electronic circuits such as preamplifier and shaper circuits and will be mounted on a robotic arm which on command brings the sensor head close to the lunar surface at a height of 35±10mm. SDD module to be used in the experiment has 30mm ^{2} active detector area with in-built peltier cooler and heat sink to maintain the detector at about -35°C. The detector is covered with 8 micron thick Be window which results in the low energy threshold of about 1keV. The size of the APXS sensor head is 70x70x70mm ^{3} (approx). APXS signal

Improving Planetary Rover Attitude Estimation via MEMS Sensor Characterization

Science.gov (United States)

Hidalgo, Javier; Poulakis, Pantelis; Köhler, Johan; Del-Cerro, Jaime; Barrientos, Antonio

2012-01-01

Micro Electro-Mechanical Systems (MEMS) are currently being considered in the space sector due to its suitable level of performance for spacecrafts in terms of mechanical robustness with low power consumption, small mass and size, and significant advantage in system design and accommodation. However, there is still a lack of understanding regarding the performance and testing of these new sensors, especially in planetary robotics. This paper presents what is missing in the field: a complete methodology regarding the characterization and modeling of MEMS sensors with direct application. A reproducible and complete approach including all the intermediate steps, tools and laboratory equipment is described. The process of sensor error characterization and modeling through to the final integration in the sensor fusion scheme is explained with detail. Although the concept of fusion is relatively easy to comprehend, carefully characterizing and filtering sensor information is not an easy task and is essential for good performance. The strength of the approach has been verified with representative tests of novel high-grade MEMS inertia sensors and exemplary planetary rover platforms with promising results. PMID:22438761

Mars Exploration Rovers Launch Performance and TCM-1 Maneuver Design

Science.gov (United States)

Kangas, Julie A.; Potts, Christopher L.; Raofi, Behzad

2004-01-01

The Mars Exploration Rover (MER) project successfully landed two identical rovers on Mars in order to remotely conduct geologic investigations, including characterization of rocks and soils that may hold clues to past water activity. Two landing sites, Gusev crater and Meridiani Planum, were selected out of nearly 200 candidate sites after balancing science returns and flight system engineering and safety. Precise trajectory targeting and control was necessary to achieve the atmospheric entry requirements for the selected landing sites within the flight system constraints. This paper discusses the expected and achieved launch vehicle performance and the impacts of that performance on the first Trajectory Correction Maneuver (TCM-1) while maintaining targeting flexibility in accommodating additional project concerns about landing site safety and possible in-flight retargeting to alternate landing sites.

78 FR 19742 - Centennial Challenges: 2014 Night Rover Challenge

Science.gov (United States)

2013-04-02

... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION [Notice 13-032] Centennial Challenges: 2014 Night... Centennial Challenges 2014 Night Rover Challenge. SUMMARY: This notice is issued in accordance with 51 U.S.C.... Centennial Challenges is a program of prize competitions to stimulate innovation in technologies of interest...

Rover-Based Instrumentation and Scientific Investigations During the 2012 Analog Field Test on Mauna Kea Volcano, Hawaii

Science.gov (United States)

Graham, L. D.; Graff, T. G.

2013-01-01

Rover-based 2012 Moon and Mars Analog Mission Activities (MMAMA) were recently completed on Mauna Kea Volcano, Hawaii. Scientific investigations, scientific input, and operational constraints were tested in the context of existing project and protocols for the field activities designed to help NASA achieve the Vision for Space Exploration [1]. Several investigations were conducted by the rover mounted instruments to determine key geophysical and geochemical properties of the site, as well as capture the geological context of the area and the samples investigated. The rover traverse and associated science investigations were conducted over a three day period on the southeast flank of the Mauna Kea Volcano, Hawaii. The test area was at an elevation of 11,500 feet and is known as "Apollo Valley" (Fig. 1). Here we report the integration and operation of the rover-mounted instruments, as well as the scientific investigations that were conducted.

Electrical power technology for robotic planetary rovers

Science.gov (United States)

Bankston, C. P.; Shirbacheh, M.; Bents, D. J.; Bozek, J. M.

1993-01-01

Power technologies which will enable a range of robotic rover vehicle missions by the end of the 1990s and beyond are discussed. The electrical power system is the most critical system for reliability and life, since all other on board functions (mobility, navigation, command and data, communications, and the scientific payload instruments) require electrical power. The following are discussed: power generation, energy storage, power management and distribution, and thermal management.

Autonomous Warplanes: NASA Rovers Lead the Way

Science.gov (United States)

2016-04-01

Warplanes NASA Rovers Lead the Way Michael R. Schroer Major, Air National Guard Wright Flyer No. 54 Air University Press Air Force Research Institute...between most airports across the continent proved an excellent further education in aviation. Piloting a business jet on a weeklong, 11- hop trek across...Research con- ducted by the National Aeronautics and Space Administration ( NASA ) offers useful lessons for the development of future military RPAs

Microbial Ecology of a Crewed Rover Traverse in the Arctic: Low Microbial Dispersal and Implications for Planetary Protection on Human Mars Missions.

Science.gov (United States)

Schuerger, Andrew C; Lee, Pascal

2015-06-01

Between April 2009 and July 2011, the NASA Haughton-Mars Project (HMP) led the Northwest Passage Drive Expedition (NWPDX), a multi-staged long-distance crewed rover traverse along the Northwest Passage in the Arctic. In April 2009, the HMP Okarian rover was driven 496 km over sea ice along the Northwest Passage, from Kugluktuk to Cambridge Bay, Nunavut, Canada. During the traverse, crew members collected samples from within the rover and from undisturbed snow-covered surfaces around the rover at three locations. The rover samples and snow samples were stored at subzero conditions (-20°C to -1°C) until processed for microbial diversity in labs at the NASA Kennedy Space Center, Florida. The objective was to determine the extent of microbial dispersal away from the rover and onto undisturbed snow. Interior surfaces of the rover were found to be associated with a wide range of bacteria (69 unique taxa) and fungi (16 unique taxa). In contrast, snow samples from the upwind, downwind, uptrack, and downtrack sample sites exterior to the rover were negative for both bacteria and fungi except for two colony-forming units (cfus) recovered from one downwind (1 cfu; site A4) and one uptrack (1 cfu; site B6) sample location. The fungus, Aspergillus fumigatus (GenBank JX517279), and closely related bacteria in the genus Brevibacillus were recovered from both snow (B. agri, GenBank JX517278) and interior rover surfaces. However, it is unknown whether the microorganisms were deposited onto snow surfaces at the time of sample collection (i.e., from the clothing or skin of the human operator) or via airborne dispersal from the rover during the 12-18 h layovers at the sites prior to collection. Results support the conclusion that a crewed rover traveling over previously undisturbed terrain may not significantly contaminate the local terrain via airborne dispersal of propagules from the vehicle.

Microbial Ecology of a Crewed Rover Traverse in the Arctic: Low Microbial Dispersal and Implications for Planetary Protection on Human Mars Missions

Science.gov (United States)

Schuerger, Andrew C.; Lee, Pascal

2015-01-01

Between April 2009 and July 2011, the NASA Haughton-Mars Project (HMP) led the Northwest Passage Drive Expedition (NWPDX), a multi-staged long-distance crewed rover traverse along the Northwest Passage in the Arctic. In April 2009, the HMP Okarian rover was driven 496 km over sea ice along the Northwest Passage, from Kugluktuk to Cambridge Bay, Nunavut, Canada. During the traverse, crew members collected samples from within the rover and from undisturbed snow-covered surfaces around the rover at three locations. The rover samples and snow samples were stored at subzero conditions (-20C to -1C) until processed for microbial diversity in labs at the NASA Kennedy Space Center, Florida. The objective was to determine the extent of microbial dispersal away from the rover and onto undisturbed snow. Interior surfaces of the rover were found to be associated with a wide range of bacteria (69 unique taxa) and fungi (16 unique taxa). In contrast, snow samples from the upwind, downwind, uptrack, and downtrack sample sites exterior to the rover were negative for both bacteria and fungi except for two colony-forming units (cfus) recovered from one downwind (1 cfu; site A4) and one uptrack (1 cfu; site B6) sample location. The fungus, Aspergillus fumigatus (GenBank JX517279), and closely related bacteria in the genus Brevibacillus were recovered from both snow (B. agri, GenBank JX517278) and interior rover surfaces. However, it is unknown whether the microorganisms were deposited onto snow surfaces at the time of sample collection (i.e., from the clothing or skin of the human operator) or via airborne dispersal from the rover during the 12-18 h layovers at the sites prior to collection. Results support the conclusion that a crewed rover traveling over previously undisturbed terrain may not significantly contaminate the local terrain via airborne dispersal of propagules from the vehicle. Key Words: Planetary protection-Contamination-Habitability-Haughton Crater-Mars. Astrobiology

Fault-Tolerant Control Strategy for Steering Failures in Wheeled Planetary Rovers

Directory of Open Access Journals (Sweden)

Alexandre Carvalho Leite

2012-01-01

Full Text Available Fault-tolerant control design of wheeled planetary rovers is described. This paper covers all steps of the design process, from modeling/simulation to experimentation. A simplified contact model is used with a multibody simulation model and tuned to fit the experimental data. The nominal mode controller is designed to be stable and has its parameters optimized to improve tracking performance and cope with physical boundaries and actuator saturations. This controller was implemented in the real rover and validated experimentally. An impact analysis defines the repertory of faults to be handled. Failures in steering joints are chosen as fault modes; they combined six fault modes and a total of 63 possible configurations of these faults. The fault-tolerant controller is designed as a two-step procedure to provide alternative steering and reuse the nominal controller in a way that resembles a crab-like driving mode. Three fault modes are injected (one, two, and three failed steering joints in the real rover to evaluate the response of the nonreconfigured and reconfigured control systems in face of these faults. The experimental results justify our proposed fault-tolerant controller very satisfactorily. Additional concluding comments and an outlook summarize the lessons learned during the whole design process and foresee the next steps of the research.

Comparing orbiter and rover image-based mapping of an ancient sedimentary environment, Aeolis Palus, Gale crater, Mars

Science.gov (United States)

Stack, Kathryn M.; Edwards, Christopher; Grotzinger, J. P.; Gupta, S.; Sumner, D.; Edgar, Lauren; Fraeman, A.; Jacob, S.; LeDeit, L.; Lewis, K.W.; Rice, M.S.; Rubin, D.; Calef, F.; Edgett, K.; Williams, R.M.E.; Williford, K.H.

2016-01-01

This study provides the first systematic comparison of orbital facies maps with detailed ground-based geology observations from the Mars Science Laboratory (MSL) Curiosity rover to examine the validity of geologic interpretations derived from orbital image data. Orbital facies maps were constructed for the Darwin, Cooperstown, and Kimberley waypoints visited by the Curiosity rover using High Resolution Imaging Science Experiment (HiRISE) images. These maps, which represent the most detailed orbital analysis of these areas to date, were compared with rover image-based geologic maps and stratigraphic columns derived from Curiosity’s Mast Camera (Mastcam) and Mars Hand Lens Imager (MAHLI). Results show that bedrock outcrops can generally be distinguished from unconsolidated surficial deposits in high-resolution orbital images and that orbital facies mapping can be used to recognize geologic contacts between well-exposed bedrock units. However, process-based interpretations derived from orbital image mapping are difficult to infer without known regional context or observable paleogeomorphic indicators, and layer-cake models of stratigraphy derived from orbital maps oversimplify depositional relationships as revealed from a rover perspective. This study also shows that fine-scale orbital image-based mapping of current and future Mars landing sites is essential for optimizing the efficiency and science return of rover surface operations.

In-motion initial alignment and positioning with INS/CNS/ODO integrated navigation system for lunar rovers

Science.gov (United States)

Lu, Jiazhen; Lei, Chaohua; Yang, Yanqiang; Liu, Ming

2017-06-01

Many countries have been paying great attention to space exploration, especially about the Moon and the Mars. Autonomous and high-accuracy navigation systems are needed for probers and rovers to accomplish missions. Inertial navigation system (INS)/celestial navigation system (CNS) based navigation system has been used widely on the lunar rovers. Initialization is a particularly important step for navigation. This paper presents an in-motion alignment and positioning method for lunar rovers by INS/CNS/odometer integrated navigation. The method can estimate not only the position and attitude errors, but also the biases of the accelerometers and gyros using the standard Kalman filter. The differences between the platform star azimuth, elevation angles and the computed star azimuth, elevation angles, and the difference between the velocity measured by odometer and the velocity measured by inertial sensors are taken as measurements. The semi-physical experiments are implemented to demonstrate that the position error can reduce to 10 m and attitude error is within 2″ during 5 min. The experiment results prove that it is an effective and attractive initialization approach for lunar rovers.

MSR Fetch Rover Capability Development at the Canadian Space Agency

Science.gov (United States)

Picard, M.; Hipkin, V.; Gingras, D.; Allard, P.; Lamarche, T.; Rocheleau, S. G.; Gemme, S.

2018-04-01

Describes Fetch Rover technology testing during CSA's 2016 Mars Sample Return Analogue Deployment which demonstrated autonomous navigation to 'cache depots' of M-2020-like sample tubes, acquisition of six such tubes, and transfer to a MAV mock up.

Wind-Driven Erosion and Exposure Potential at Mars 2020 Rover Candidate-Landing Sites

Science.gov (United States)

Chojnacki, Matthew; Banks, Maria; Urso, Anna

2018-01-01

Aeolian processes have likely been the predominant geomorphic agent for most of Mars’ history and have the potential to produce relatively young exposure ages for geologic units. Thus, identifying local evidence for aeolian erosion is highly relevant to the selection of landing sites for future missions, such as the Mars 2020 Rover mission that aims to explore astrobiologically relevant ancient environments. Here we investigate wind-driven activity at eight Mars 2020 candidate-landing sites to constrain erosion potential at these locations. To demonstrate our methods, we found that contemporary dune-derived abrasion rates were in agreement with rover-derived exhumation rates at Gale crater and could be employed elsewhere. The Holden crater candidate site was interpreted to have low contemporary erosion rates, based on the presence of a thick sand coverage of static ripples. Active ripples at the Eberswalde and southwest Melas sites may account for local erosion and the dearth of small craters. Moderate-flux regional dunes near Mawrth Vallis were deemed unrepresentative of the candidate site, which is interpreted to currently be experiencing low levels of erosion. The Nili Fossae site displayed the most unambiguous evidence for local sand transport and erosion, likely yielding relatively young exposure ages. The downselected Jezero crater and northeast Syrtis sites had high-flux neighboring dunes and exhibited substantial evidence for sediment pathways across their ellipses. Both sites had relatively high estimated abrasion rates, which would yield young exposure ages. The downselected Columbia Hills site lacked evidence for sand movement, and contemporary local erosion rates are estimated to be relatively low. PMID:29568719

Wind-Driven Erosion and Exposure Potential at Mars 2020 Rover Candidate-Landing Sites

Science.gov (United States)

Chojnacki, Matthew; Banks, Maria; Urso, Anna

2018-02-01

Aeolian processes have likely been the predominant geomorphic agent for most of Mars' history and have the potential to produce relatively young exposure ages for geologic units. Thus, identifying local evidence for aeolian erosion is highly relevant to the selection of landing sites for future missions, such as the Mars 2020 Rover mission that aims to explore astrobiologically relevant ancient environments. Here we investigate wind-driven activity at eight Mars 2020 candidate-landing sites to constrain erosion potential at these locations. To demonstrate our methods, we found that contemporary dune-derived abrasion rates were in agreement with rover-derived exhumation rates at Gale crater and could be employed elsewhere. The Holden crater candidate site was interpreted to have low contemporary erosion rates, based on the presence of a thick sand coverage of static ripples. Active ripples at the Eberswalde and southwest Melas sites may account for local erosion and the dearth of small craters. Moderate-flux regional dunes near Mawrth Vallis were deemed unrepresentative of the candidate site, which is interpreted to currently be experiencing low levels of erosion. The Nili Fossae site displayed the most unambiguous evidence for local sand transport and erosion, likely yielding relatively young exposure ages. The downselected Jezero crater and northeast Syrtis sites had high-flux neighboring dunes and exhibited substantial evidence for sediment pathways across their ellipses. Both sites had relatively high estimated abrasion rates, which would yield young exposure ages. The downselected Columbia Hills site lacked evidence for sand movement, and contemporary local erosion rates are estimated to be relatively low.

An Overview of Wind-Driven Rovers for Planetary Exploration

Science.gov (United States)

Hajos, Gregory A.; Jones, Jack A.; Behar, Alberto; Dodd, Micheal

2005-01-01

The use of in-situ propulsion is considered enabling technology for long duration planetary surface missions. Most studies have focused on stored energy from chemicals extracted from the soil or the use of soil chemicals to produce photovoltaic arrays. An older form of in-situ propulsion is the use of wind power. Recent studies have shown potential for wind driven craft for exploration of Mars, Titan and Venus. The power of the wind, used for centuries to power wind mills and sailing ships, is now being applied to modern land craft. Efforts are now underway to use the wind to push exploration vehicles on other planets and moons in extended survey missions. Tumbleweed rovers are emerging as a new type of wind-driven science platform concept. Recent investigations by the National Aeronautics and Space Administration (NASA) and Jet Propulsion Laboratory (JPL) indicate that these light-weight, mostly spherical or quasi-spherical devices have potential for long distance surface exploration missions. As a power boat has unique capabilities, but relies on stored energy (fuel) to move the vessel, the Tumbleweed, like the sailing ships of the early explorers on earth, uses an unlimited resource the wind to move around the surface of Mars. This has the potential to reduce the major mass drivers of robotic rovers as well as the power generation and storage systems. Jacques Blamont of JPL and the University of Paris conceived the first documented Mars wind-blown ball in 1977, shortly after the Viking landers discovered that Mars has a thin CO2 atmosphere with relatively strong winds. In 1995, Jack Jones, et al, of JPL conceived of a large wind-blown inflated ball for Mars that could also be driven and steered by means of a motorized mass hanging beneath the rolling axis of the ball. A team at NASA Langley Research Center started a biomimetic Tumbleweed design study in 1998. Wind tunnel and CFD analysis were applied to a variety of concepts to optimize the aerodynamic

Technical and regulatory review of the Rover nuclear fuel process for use on Fort St. Vrain fuel

International Nuclear Information System (INIS)

Hertzler, T.

1993-02-01

This report describes the results of an analysis for processing and final disposal of Fort St. Vrain (FSV) irradiated fuel in Rover-type equipment or technologies. This analysis includes an evaluation of the current Rover equipment status and the applicability of this technology in processing FSV fuel. The analyses are based on the physical characteristics of the FSV fuel and processing capabilities of the Rover equipment. Alternate FSV fuel disposal options are also considered including fuel-rod removal from the block, disposal of the empty block, or disposal of the entire fuel-containing block. The results of these analyses document that the current Rover hardware is not operable for any purpose, and any effort to restart this hardware will require extensive modifications and re-evaluation. However, various aspects of the Rover technology, such as the successful fluid-bed burner design, can be applied with modification to FSV fuel processing. The current regulatory climate and technical knowledge are not adequately defined to allow a complete analysis and conclusion with respect to the disposal of intact fuel blocks with or without the fuel rods removed. The primary unknowns include the various aspects of fuel-rod removal from the block, concentration of radionuclides remaining in the graphite block after rod removal, and acceptability of carbon in the form of graphite in a high level waste repository

INTERNATIONAL CORPORATE RELATIONS : Strategic Alliance and M&A : The Case of Honda, Rover and BMW

OpenAIRE

勝二, 俊和; ショウジ, トシカズ; TOSHIKAZU, SHOJI

1998-01-01

The primary objective of the dissertation is to compare and contrast two strategies of international corporate relations; "strategic alliances" and "mergers and acquisitions". The focus would be on Honda, Rover and BMW which exhibited characteristics, strengths and weaknesses of both "strategic alliances" and "mergers and acquisitions" The thesis will also demonstrate how the BMW deal caused instability and thus made the alliance vulnerable. When companies like Honda, Rover and BMW adopt eith...

Reasoning with inaccurate spatial knowledge. [for Planetary Rover

Science.gov (United States)

Doshi, Rajkumar S.; White, James E.; Lam, Raymond; Atkinson, David J.

1988-01-01

This paper describes work in progress on spatial planning for a semiautonomous mobile robot vehicle. The overall objective is to design a semiautonomous rover to plan routes in unknown, natural terrains. The approach to spatial planning involves deduction of common-sense spatial knowledge using geographical information, natural terrain representations, and assimilation of new and possibly conflicting terrain information. This report describes the ongoing research and implementation.

ExoGeoLab Pilot Project for Landers, Rovers and Instruments

Science.gov (United States)

Foing, Bernard

2010-05-01

We have developed a pilot facility with a Robotic Test Bench (ExoGeoLab) and a Mobile Lab Habitat (ExoHab). They can be used to validate concepts and external instruments from partner institutes. The ExoGeoLab research incubator project, has started in the frame of a collaboration between ILEWG (International Lunar Exploration working Group http://sci.esa.int/ilewg), ESTEC, NASA and academic partners, supported by a design and control desk in the European Space Incubator (ESI), as well as infrastructure. ExoGeoLab includes a sequence of technology and research pilot project activities: - Data analysis and interpretation of remote sensing and in-situ data, and merging of multi-scale data sets - Procurement and integration of geophysical, geo-chemical and astrobiological breadboard instruments on a surface station and rovers - Integration of cameras, environment and solar sensors, Visible and near IR spectrometer, Raman spectrometer, sample handling, cooperative rovers - Delivery of a generic small planetary lander demonstrator (ExoGeoLab lander, Sept 2009) as a platform for multi-instruments tests - Research operations and exploitation of ExoGeoLab test bench for various conceptual configurations, and support for definition and design of science surface packages (Moon, Mars, NEOs, outer moons) - Field tests of lander, rovers and instruments in analogue sites (Utah MDRS 2009 & 2010, Eifel volcanic park in Sept 2009, and future campaigns). Co-authors, ILEWG ExoGeoLab & ExoHab Team: B.H. Foing(1,11)*#, C. Stoker(2,11)*, P. Ehrenfreund(10,11), L. Boche-Sauvan(1,11)*, L. Wendt(8)*, C. Gross(8, 11)*, C. Thiel(9)*, S. Peters(1,6)*, A. Borst(1,6)*, J. Zavaleta(2)*, P. Sarrazin(2)*, D. Blake(2), J. Page(1,4,11), V. Pletser(5,11)*, E. Monaghan(1)*, P. Mahapatra(1)#, A. Noroozi(3), P. Giannopoulos(1,11) , A. Calzada(1,6,11), R. Walker(7), T. Zegers(1, 15) #, G. Groemer(12)# , W. Stumptner(12)#, B. Foing(2,5), J. K. Blom(3)#, A. Perrin(14)#, M. Mikolajczak(14)#, S. Chevrier(14

CFD Analysis for Assessing the Effect of Wind on the Thermal Control of the Mars Science Laboratory Curiosity Rover

Science.gov (United States)

Bhandari, Pradeep; Anderson, Kevin

2013-01-01

The challenging range of landing sites for which the Mars Science Laboratory Rover was designed, requires a rover thermal management system that is capable of keeping temperatures controlled across a wide variety of environmental conditions. On the Martian surface where temperatures can be as cold as -123 C and as warm as 38 C, the rover relies upon a Mechanically Pumped Fluid Loop (MPFL) Rover Heat Rejection System (RHRS) and external radiators to maintain the temperature of sensitive electronics and science instruments within a -40 C to 50 C range. The RHRS harnesses some of the waste heat generated from the rover power source, known as the Multi Mission Radioisotope Thermoelectric Generator (MMRTG), for use as survival heat for the rover during cold conditions. The MMRTG produces 110 W of electrical power while generating waste heat equivalent to approximately 2000 W. Heat exchanger plates (hot plates) positioned close to the MMRTG pick up this survival heat from it by radiative heat transfer. Winds on Mars can be as fast as 15 m/s for extended periods. They can lead to significant heat loss from the MMRTG and the hot plates due to convective heat pick up from these surfaces. Estimation of this convective heat loss cannot be accurately and adequately achieved by simple textbook based calculations because of the very complicated flow fields around these surfaces, which are a function of wind direction and speed. Accurate calculations necessitated the employment of sophisticated Computational Fluid Dynamics (CFD) computer codes. This paper describes the methodology and results of these CFD calculations. Additionally, these results are compared to simple textbook based calculations that served as benchmarks and sanity checks for them. And finally, the overall RHRS system performance predictions will be shared to show how these results affected the overall rover thermal performance.

Applied design methodology for lunar rover elastic wheel

Science.gov (United States)

Cardile, Diego; Viola, Nicole; Chiesa, Sergio; Rougier, Alessandro

2012-12-01

In recent years an increasing interest in the Moon surface operations has been experienced. In the future robotic and manned missions of Moon surface exploration will be fundamental in order to lay the groundwork for more ambitious space exploration programs. Surface mobility systems will be the key elements to ensure an efficient and safe Moon exploration. Future lunar rovers are likely to be heavier and able to travel longer distances than the previously developed Moon rover systems. The Lunar Roving Vehicle (LRV) is the only manned rover, which has so far been launched and used on the Moon surface. Its mobility system included flexible wheels that cannot be scaled to the heavier and longer range vehicles. Thus the previously developed wheels are likely not to be suitable for the new larger vehicles. Taking all these considerations into account, on the basis of the system requirements and assumptions, several wheel concepts have been discussed and evaluated through a trade-off analysis. Semi-empirical equations have been utilized to predict the wheel geometrical characteristics, as well as to estimate the motion resistances and the ability of the system to generate thrust. A numerical model has also been implemented, in order to define more into the details the whole wheel design, in terms of wheel geometry and physical properties. As a result of the trade-off analysis, the ellipse wheel concept has shown the best behavior in terms of stiffness, mass budget and dynamic performance. The results presented in the paper have been obtained in cooperation with Thales Alenia Space-Italy and Sicme motori, in the framework of a regional program called STEPS . STEPS-Sistemi e Tecnologie per l'EsPlorazione Spaziale is a research project co-financed by Piedmont Region and firms and universities of the Piedmont Aerospace District in the ambit of the P.O.R-F.E.S.R. 2007-2013 program.

The Antarctic permafrost as a testbed for REMS (Rover Environmental Monitoring Station-Mars Science Laboratory)

Science.gov (United States)

Esteban, B.; Ramos, M.; Sebastián, E.; Armiens, C.; Gómez-Elvira, J.; Cabos, W.; de Pablo, M. A.

2009-04-01

The present climatic characteristics of Mars favor the presence of extense permafrost areas in this lonely planet. Therefore environmental parameters that are included in Martian Rover missions are also used for monitoring thermal soil surface evolution in order to study the permafrost active layer thickness and the energy balance in the soil-atmosphere boundary limit layer. The REMS (Rover Environmental Monitoring Station) is an environmental station designed by the Centro de Astrobiología (CAB- Spain) with the collaboration of national and international partners (CRISA/EADS, UPC and FMI), which is part of the payload of the MSL (Mars Science Laboratory) NASA mission to Mars (http://mars.jpl.nasa.gov/msl/overview/). This mission is expected to be launched in the final months of 2009, and mainly consists of a Rover, with a complete set of scientific instruments; the Rover will carry the biggest, most advanced suite of instruments for scientific studies ever sent to the Martian surface. Five sensors compose the REMS instrument: ground (GT-REMS) and air temperatures, wind speed and direction, pressure, humidity and ultraviolet radiation (UV-REMS). A simplified setup of the REMS was deployed on Antarctica in the surroundings of the Spanish Antarctic Stations on Livingston and Deception Islands (Maritime Antarctica), where the permafrost distribution is well-known. The aim of the experiment was to check REMS's sensors response against hard environmental conditions and calibrates their measures with standard Antarctic devices. The experimental apparatuses included some standard meteorological and thermopiles sensors corresponding to the REMS. All the sensors are mounted in a 1.8 m mast and include a Pt100 air temperature sensor with shield solar protection on the mast top, a Kipp and Zonnen CNR1 net radiometer for measuring infrared (5-50 μm) and short wave solar (305-2800 nm) radiation at 1.5 m high, GT-REMS sensor and its amplification box at 0.7 m high and finally

Large-area Soil Moisture Surveys Using a Cosmic-ray Rover: Approaches and Results from Australia

Science.gov (United States)

Hawdon, A. A.; McJannet, D. L.; Renzullo, L. J.; Baker, B.; Searle, R.

2017-12-01

Recent improvements in satellite instrumentation has increased the resolution and frequency of soil moisture observations, and this in turn has supported the development of higher resolution land surface process models. Calibration and validation of these products is restricted by the mismatch of scales between remotely sensed and contemporary ground based observations. Although the cosmic ray neutron soil moisture probe can provide estimates soil moisture at a scale useful for the calibration and validation purposes, it is spatially limited to a single, fixed location. This scaling issue has been addressed with the development of mobile soil moisture monitoring systems that utilizes the cosmic ray neutron method, typically referred to as a `rover'. This manuscript describes a project designed to develop approaches for undertaking rover surveys to produce soil moisture estimates at scales comparable to satellite observations and land surface process models. A custom designed, trailer-mounted rover was used to conduct repeat surveys at two scales in the Mallee region of Victoria, Australia. A broad scale survey was conducted at 36 x 36 km covering an area of a standard SMAP pixel and an intensive scale survey was conducted over a 10 x 10 km portion of the broad scale survey, which is at a scale equivalent to that used for national water balance modelling. We will describe the design of the rover, the methods used for converting neutron counts into soil moisture and discuss factors controlling soil moisture variability. We found that the intensive scale rover surveys produced reliable soil moisture estimates at 1 km resolution and the broad scale at 9 km resolution. We conclude that these products are well suited for future analysis of satellite soil moisture retrievals and finer scale soil moisture models.

Mimicking Martian dust: An in-vacuum dust deposition system for testing the ultraviolet sensors on the Curiosity rover

International Nuclear Information System (INIS)

Sobrado, J. M.; Martín-Soler, J.; Martín-Gago, J. A.

2015-01-01

We have designed and developed an in-vacuum dust deposition system specifically conceived to simulate and study the effect of accumulation of Martian dust on the electronic instruments of scientific planetary exploration missions. We have used this device to characterize the dust effect on the UV sensor of the Rover Environmental Monitoring Station in the Mars science Laboratory mission of NASA in similar conditions to those found on Mars surface. The UV sensor includes six photodiodes for measuring the radiation in all UV wavelengths (direct incidence and reflected); it is placed on the body of Curiosity rover and it is severely affected by the dust deposited on it. Our experimental setup can help to estimate the duration of reliable reading of this instrument during operation. We have used an analogous of the Martian dust in chemical composition (magnetic species), color, and density, which has been characterized by X-ray spectroscopy. To ensure a Brownian motion of the dust during its fall and a homogeneous coverage on the instrumentation, the operating conditions of the vacuum vessel, determined by partial pressures and temperature, have to be modified to account for the different gravities of Mars with respect to Earth. We propose that our designed device and operational protocol can be of interest to test optoelectronic instrumentation affected by the opacity of dust, as can be the degradation of UV photodiodes in planetary exploration

Mimicking Martian dust: An in-vacuum dust deposition system for testing the ultraviolet sensors on the Curiosity rover

Energy Technology Data Exchange (ETDEWEB)

Sobrado, J. M., E-mail: sobradovj@inta.es; Martín-Soler, J. [Centro de Astrobiología (CAB), INTA-CSIC, Torrejón de Ardoz, 28850 Madrid (Spain); Martín-Gago, J. A. [Centro de Astrobiología (CAB), INTA-CSIC, Torrejón de Ardoz, 28850 Madrid (Spain); Instituto de Ciencias de Materiales de Madrid (ICMM–CSIC), Cantoblanco, 28049 Madrid (Spain)

2015-10-15

We have designed and developed an in-vacuum dust deposition system specifically conceived to simulate and study the effect of accumulation of Martian dust on the electronic instruments of scientific planetary exploration missions. We have used this device to characterize the dust effect on the UV sensor of the Rover Environmental Monitoring Station in the Mars science Laboratory mission of NASA in similar conditions to those found on Mars surface. The UV sensor includes six photodiodes for measuring the radiation in all UV wavelengths (direct incidence and reflected); it is placed on the body of Curiosity rover and it is severely affected by the dust deposited on it. Our experimental setup can help to estimate the duration of reliable reading of this instrument during operation. We have used an analogous of the Martian dust in chemical composition (magnetic species), color, and density, which has been characterized by X-ray spectroscopy. To ensure a Brownian motion of the dust during its fall and a homogeneous coverage on the instrumentation, the operating conditions of the vacuum vessel, determined by partial pressures and temperature, have to be modified to account for the different gravities of Mars with respect to Earth. We propose that our designed device and operational protocol can be of interest to test optoelectronic instrumentation affected by the opacity of dust, as can be the degradation of UV photodiodes in planetary exploration.

Condensation pressures in small pores: An analytical model based on density functional theory

International Nuclear Information System (INIS)

Nilson, R.H.; Griffiths, S.K.

1999-01-01

Integral methods are used to derive an analytical expression describing fluid condensation pressures in slit pores bounded by parallel plane walls. To obtain this result, the governing equations of density functional theory (DFT) are integrated across the pore width assuming that fluid densities within adsorbed layers are spatially uniform. The thickness, density, and free energy of these layers are expressed as composite functions constructed from asymptotic limits applicable to small and large pores. By equating the total free energy of the adsorbed layers to that of a liquid-full pore, we arrive at a closed-form expression for the condensation pressure in terms of the pore size, surface tension, and Lennard-Jones parameters of the adsorbent and adsorbate molecules. The resulting equation reduces to the Kelvin equation in the large-pore limit. It further reproduces the condensation pressures computed by means of the full DFT equations for all pore sizes in which phase transitions are abrupt. Finally, in the limit of extremely small pores, for which phase transitions may be smooth and continuous, this simple analytical expression provides a good approximation to the apparent condensation pressure indicated by the steepest portion of the adsorption isotherm computed via DFT. copyright 1999 American Institute of Physics

Visualisation of very high resolution Martian topographic data and its application on landing site selection and rover route navigation

Science.gov (United States)

Kim, J.; Lin, S.; Hong, J.; Park, D.; Yoon, S.; Kim, Y.

2010-12-01

High resolution satellite imagery acquired from orbiters are able to provide detailed topographic information and therefore are recognised as an important tool for investigating planetary and terrestrial topography. The heritage of in-orbit high resolution imaging technology is now implemented in a series of Martian Missions, such as HiRISE (High Resolution Imaging Science Experiment) and CTX (Context Camera) onboard the MRO (Mars Reconnaissance Orbiter). In order to fully utilise the data derived from image systems carried on various Mars orbiters, the generalised algorithms of image processing and photogrammetric Mars DTM extraction have been developed and implemented by Kim and Muller (2009), in which non-rigorous sensor model and hierarchical geomatics control were employed. Due to the successful “from medium to high” control strategy performed during processing, stable horizontal and vertical photogrammetric accuracy of resultant Mars DTM was achievable when compared with MOLA (Mars Obiter Laser Altimeter) DTM. Recently, the algorithms developed in Kim and Muller (2009) were further updated by employing advanced image matcher and improved sensor model. As the photogrammetric qualities of the updated topographic products are verified and the spatial solution can be up to sub-meter scale, they are of great value to be exploited for Martian rover landing site selection and rover route navigation. To this purpose, the DTMs and ortho-rectified imagery obtained from CTX and HiRISE covering potential future rovers and existing MER (Mars Exploration Rover) landing sites were firstly processed. For landing site selection, the engineering constraints such as slope and surface roughness were computed from DTMs. In addition, the combination of virtual topography and the estimated rover location was able to produce a sophisticated environment simulation of rover’s landing site. Regarding the rover navigation, the orbital DTMs and the images taken from cameras

Rover exploration on the lunar surface; a science proposal for SELENE-B mission

Science.gov (United States)

Sasaki, S.; Kubota, T.; Akiyama, H.; Hirata, N.; Kunii, Y.; Matsumoto, K.; Okada, T.; Otake, M.; Saiki, K.; Sugihara, T.

LUNARSURFACE:ASCIENCES. Sasaki (1), T. Kubota (2) , H. Akiyama (1) , N. Hirata (3), Y. Kunii (4), K. Matsumoto (5), T. Okada (2), M. Otake (3), K. Saiki (6), T. Sugihara (3) (1) Department of Earth and Planetary Science, Univ. Tokyo, (2) Institute of Space and Astronautical Sciences, (3) National Space Development Agency of Japan, (4) Department of Electrical and Electronic Engineering, Chuo Univ., (5) National Aerospace Laboratory of Japan, (6) Research Institute of Materials and Resources, Akita Univ. sho@eps.s.u -tokyo.ac.jp/Fax:+81-3-5841-4569 A new lunar landing mission (SELENE-B) is now in consideration in Japan. Scientific investigation plans using a rover are proposed. To clarify the origin and evolution of the moon, the early crustal formation and later mare volcanic processes are still unveiled. We proposed two geological investigation plans: exploration of a crater central peak to discover subsurface materials and exploration of dome-cone structures on young mare region. We propose multi-band macro/micro camera using AOTF, X-ray spectrometer/diffractometer and gamma ray spectrometer. Since observation of rock fragments in brecciaed rocks is necessary, the rover should have cutting or scraping mechanism of rocks. In our current scenario, landing should be performed about 500m from the main target (foot of a crater central peak or a cone/dome). After the spectral survey by multi-band camera on the lander, the rover should be deployed for geological investigation. The rover should make a short (a few tens meter) round trip at first, then it should perform traverse observation toward the main target. Some technological investigations on SELENE-B project will be also presented.

Scaling up high throughput field phenotyping of corn and soy research plots using ground rovers

Science.gov (United States)

Peshlov, Boyan; Nakarmi, Akash; Baldwin, Steven; Essner, Scott; French, Jasenka

2017-05-01

Crop improvement programs require large and meticulous selection processes that effectively and accurately collect and analyze data to generate quality plant products as efficiently as possible, develop superior cropping and/or crop improvement methods. Typically, data collection for such testing is performed by field teams using hand-held instruments or manually-controlled devices. Although steps are taken to reduce error, the data collected in such manner can be unreliable due to human error and fatigue, which reduces the ability to make accurate selection decisions. Monsanto engineering teams have developed a high-clearance mobile platform (Rover) as a step towards high throughput and high accuracy phenotyping at an industrial scale. The rovers are equipped with GPS navigation, multiple cameras and sensors and on-board computers to acquire data and compute plant vigor metrics per plot. The supporting IT systems enable automatic path planning, plot identification, image and point cloud data QA/QC and near real-time analysis where results are streamed to enterprise databases for additional statistical analysis and product advancement decisions. Since the rover program was launched in North America in 2013, the number of research plots we can analyze in a growing season has expanded dramatically. This work describes some of the successes and challenges in scaling up of the rover platform for automated phenotyping to enable science at scale.

Brake Failure from Residual Magnetism in the Mars Exploration Rover Lander Petal Actuator

Science.gov (United States)

Jandura, Louise

2004-01-01

In January 2004, two Mars Exploration Rover spacecraft arrived at Mars. Each safely delivered an identical rover to the Martian surface in a tetrahedral lander encased in airbags. Upon landing, the airbags deflated and three Lander Petal Actuators opened the three deployable Lander side petals enabling the rover to exit the Lander. Approximately nine weeks prior to the scheduled launch of the first spacecraft, one of these mission-critical Lander Petal Actuators exhibited a brake stuck-open failure during its final flight stow at Kennedy Space Center. Residual magnetism was the definitive conclusion from the failure investigation. Although residual magnetism was recognized as an issue in the design, the lack of an appropriately specified lower bound on brake drop-out voltage inhibited the discovery of this problem earlier in the program. In addition, the brakes had more unit-to-unit variation in drop-out voltage than expected, likely due to a larger than expected variation in the magnetic properties of the 15-5 PH stainless steel brake plates. Failure analysis and subsequent rework of two other Lander Petal Actuators with marginal brakes was completed in three weeks, causing no impact to the launch date.

METEO-P/H: Measuring ambient pressure and relative humidity on the ExoMars 2020 landing site

Science.gov (United States)

Nikkanen, T. T.; Genzer, M.; Hieta, M.; Harri, A.-M.; Haukka, H.; Polkko, J.; Kynkäänniemi, T.

2017-09-01

Finnish Meteorological Institute (FMI) has designed and is in the process of building and testing a pressure and humidity measurement device for the ExoMars 2020 lander. The ExoMars 2020 mission consists of the Russian Roscosmos Surface Platform (SP) and the European Space Agency (ESA) Rover. The Surface Platform will perform the Entry, Descent and Landing for the lander combo and start stationary science operations after landing, while the Rover will drive off the SP to explore the landing site surroundings and soil. The FMI measurement device is installed on the Surface Platform to give continuous measurements from a stationary location. The METEO-P pressure device and METEO-H humidity device are part of the METEO meteorological science package, which also includes a thermometer and an anemometer from IKI, Russia, as well as the RDM Radiation and dust sensors, and the AMR magnetic field sensors from INTA, Spain.

78 FR 41369 - Certain Small Diameter Carbon and Alloy Seamless Standard, Line and Pressure Pipe From Romania...

Science.gov (United States)

2013-07-10

... Carbon and Alloy Seamless Standard, Line and Pressure Pipe From Romania: Preliminary Results of..., line and pressure pipe (small diameter seamless pipe) from Romania. The period of review (POR) is... and Alloy Seamless Standard, Line and Pressure Pipe from Romania,'' dated concurrently with this...

A new design for high stability pressure-controlled ventilation for small animal lung imaging

International Nuclear Information System (INIS)

Kitchen, M J; Habib, A; Lewis, R A; Fouras, A; Dubsky, S; Wallace, M J; Hooper, S B

2010-01-01

We have developed a custom-designed ventilator to deliver a stable pressure to the lungs of small animals for use in imaging experiments. Our ventilator was designed with independent pressure vessels to separately control the Peak Inspiratory Pressure (PIP) and Positive End Expiratory Pressure (PEEP) to minimise pressure fluctuations during the ventilation process. The ventilator was computer controlled through a LabVIEW interface, enabling experimental manipulations to be performed remotely whilst simultaneously imaging the lungs in situ. Mechanical ventilation was successfully performed on newborn rabbit pups to assess the most effective ventilation strategies for aerating the lungs at birth. Highly stable pressures enabled reliable respiratory gated acquisition of projection radiographs and a stable prolonged (15 minute) breath-hold for high-resolution computed tomography of deceased rabbit pups at different lung volumes.

Radiation shield analysis for a manned Mars rover

International Nuclear Information System (INIS)

Morley, N.J.; ElGenk, M.S.

1991-01-01

Radiation shielding for unmanned space missions has been extensively studied; however, designs of man-rated shields are minimal. Engle et al.'s analysis of a man-rated, multilayered shield composed of two and three cycles (a cycle consists of a tungsten and a lithium hydride layer) is the basis for the work reported in this paper. The authors present the results of a recent study of shield designs for a manned Mars rover powered by a 500-kW(thermal) nuclear reactor. A train-type rover vehicle was developed, which consists of four cars and is powered by an SP-100-type nuclear reactor heat source. The maximum permissible dose rate (MPD) from all sources is given by the National Council on Radiation Protection and Measurements as 500 mSv/yr (50 rem/yr) A 3-yr Mars mission (2-yr round trip and 1-yr stay) will deliver a 1-Sv natural radiation dose without a solar particle event, 450 mSv/yr in flight, and an additional 100 mSv on the planet surface. An anomalously large solar particle event could increase the natural radiation dose for unshielded astronauts on the Martian surface to 200 mSv. This limits the MPD to crew members from the nuclear reactor to 300 mSv

77 FR 67336 - Certain Small Diameter Carbon and Alloy Seamless Standard, Line and Pressure Pipe From Romania...

Science.gov (United States)

2012-11-09

... Carbon and Alloy Seamless Standard, Line and Pressure Pipe From Romania: Final Results of Antidumping... alloy seamless standard, line and pressure pipe from Romania. The period of review is August 1, 2010..., line and pressure pipe from Romania. See Certain Small Diameter Carbon and Alloy Seamless Standard...

An experimental study on two-phase pressure drop in small diameter horizontal, downward inclined and vertical tubes

Directory of Open Access Journals (Sweden)

Autee Arun

2015-01-01

Full Text Available An experimental study of two-phase pressure drop in small diameter tubes orientated horizontally, vertically and at two other downward inclinations of θ= 300 and θ = 600 is described in this paper. Acrylic transparent tubes of internal diameters 4.0, 6.0, and 8.0 mm with lengths of 400 mm were used as the test section. Air-water mixture was used as the working fluid. Two-phase pressure drop was measured and compared with the existing correlations. These correlations are commonly used for calculation of pressure drop in macro and mini-microchannels. It is observed that the existing correlations are inadequate in predicting the two-phase pressure drop in small diameter tubes. Based on the experimental data, a new correlation has been proposed for predicting the two-phase pressure drop. This correlation is developed by modification of Chisholm parameter C by incorporating different parameters. It was found that the proposed correlation predicted two-phase pressure drop at satisfactory level.

Atacama Rover Astrobiology Drilling Studies: Roving to Find Subsurface Preserved Biomarkers

Science.gov (United States)

Glass, B.; Davila, A.; Parro, V.; Quinn, R.; Willis, P.; Brinckerhoff, W.; DiRuggiero, J.; Williams, M.; Bergman, D.; Stoker, C.

2016-05-01

The ARADS project is a NASA PSTAR that will drill into a Mars analog site in search of biomarkers. Leading to a field test of an integrated rover-drill system with four prototype in-situ instruments for biomarker detection and analysis.

Condensation pressures in small pores: An analytical model based on density functional theory

Energy Technology Data Exchange (ETDEWEB)

R. H. Nilson; S. K. Griffiths

1999-02-01

Adsorption and condensation are critical to many applications of porous materials including filtration, separation, and the storage of gases. Integral methods are used to derive an analytical expression describing fluid condensation pressures in slit pores bounded by parallel plane walls. To obtain this result, the governing equations of Density Functional Theory (DFT) are integrated across the pore width assuming that fluid densities within adsorbed layers are spatially uniform. The thickness, density, and energy of these layers are expressed as composite functions constructed from asymptotic limits applicable to small and large pores. By equating the total energy of the adsorbed layers to that of a liquid-full pore, the authors arrive at a closed-form expression for the condensation pressure in terms of the pore size, surface tension, and Lennard-Jones parameters of the adsorbent and adsorbate molecules. The resulting equation reduces to the Kelvin equation in the large-pore limit. It further reproduces the condensation pressures computed by means of the full DFT equations for all pore sizes in which phase transitions are abrupt. Finally, in the limit of extremely small pores, for which phase transitions may be smooth and continuous, this simple analytical expression provides a good approximation to the apparent condensation pressure indicated by the steepest portion of the adsorption isotherm computed via DFT.

Steam explosions of molten iron oxide drops: easier initiation at small pressurizations

International Nuclear Information System (INIS)

Nelson, L.S.; Duda, P.M.

1982-01-01

Steam explosions caused by hot molten materials contacting liquid water following a possible light water nuclear reactor core overheat have been investigated by releasing single drops of a core melt simulant, molten iron oxide, into liquid water. Small steam explosions were triggered shortly afterwards by applying a pressure pulse to the water. The threshold peak pulse level above which an explosion always occurs was studied at ambient pressures between 0.083 and 1.12 MPa. It was found that the threshold decreased to a minimum in the range 0.2 - 0.8 MPa and then increased again. The effect of easier initiation as ambient pressure increases may have an important role in the triggering and propagation of a large scale steam explosion through a coarsely premixed dispersion of melt in water. (U.K.)

First results from the Mojave Volatiles Prospector (MVP) Field Campaign, a Lunar Polar Rover Mission Analog

Science.gov (United States)

Heldmann, J. L.; Colaprete, A.; Cook, A.; Deans, M. C.; Elphic, R. C.; Lim, D. S. S.; Skok, J. R.

2014-12-01

The Mojave Volatiles Prospector (MVP) project is a science-driven field program with the goal to produce critical knowledge for conducting robotic exploration of the Moon. MVP will feed science, payload, and operational lessons learned to the development of a real-time, short-duration lunar polar volatiles prospecting mission. MVP achieves these goals through a simulated lunar rover mission to investigate the composition and distribution of surface and subsurface volatiles in a natural and a priori unknown environment within the Mojave Desert, improving our understanding of how to find, characterize, and access volatiles on the Moon. The MVP field site is the Mojave Desert, selected for its low, naturally occurring water abundance. The Mojave typically has on the order of 2-6% water, making it a suitable lunar analog for this field test. MVP uses the Near Infrared and Visible Spectrometer Subsystem (NIRVSS), Neutron Spectrometer Subsystem (NSS), and a downward facing GroundCam camera on the KREX-2 rover to investigate the relationship between the distribution of volatiles and soil crust variation. Through this investigation, we mature robotic in situ instruments and concepts of instrument operations, improve ground software tools for real time science, and carry out publishable research on the water cycle and its connection to geomorphology and mineralogy in desert environments. A lunar polar rover mission is unlike prior space missions and requires a new concept of operations. The rover must navigate 3-5 km of terrain and examine multiple sites in in just ~6 days. Operational decisions must be made in real time, requiring constant situational awareness, data analysis and rapid turnaround decision support tools. This presentation will focus on the first science results and operational architecture findings from the MVP field deployment relevant to a lunar polar rover mission.

TU Berlin Rover Family for Terrestrial Testing of Complex Planetary Mission Scenarios

Science.gov (United States)

Kryza, L.; Brieß, K.

2018-04-01

The TU Berlin has developed a family of planetary rovers for educational use and research activities. The paper will introduce these cost-effective systems, which can be used for analogue mission demonstration on Earth.

Performance of the Linear Ion Trap Mass Spectrometer for the Mars Organic Molecule Analyzer (MOMA) Investigation on the 2018 Exomars Rover

Science.gov (United States)

Arevalo, Ricardo, Jr.; Brinckerhoff, William B.; Pinnick, Veronica T.; van Amerom, Friso H. W.; Danell, Ryan M.; Li, Xiang; Getty, Stephanie; Hovmand, Lars; Atanassova, Martina; Mahaffy, Paul R.;

(Nearly) Seven Years on Mars: Adventure, Adversity, and Achievements with the NASA Mars Exploration Rovers Spirit and Opportunity

Science.gov (United States)

Bell, J. F.; Mars Exploration Rover Science; Engineering Teams

2010-12-01

NASA successfully landed twin rovers, Spirit and Opportunity, on Mars in January 2004, in the most ambitious mission of robotic exploration attempted to that time. Each rover is outfitted as a robot field geologist with an impressive array of scientific instruments--cameras, spectrometers, other sensors--designed to investigate the composition and geologic history of two distinctly-different landing sites. The sites were chosen because of their potential to reveal clues about the past history of water and climate on Mars, and thus to provide tests of the hypothesis that the planet may once have been an abode for life. In this presentation I will review the images, spectra, and chemical/mineralogic information that the rover team has been acquiring from the landing sites and along the rovers' 7.7 and 22.7 km traverse paths, respectively. The data and interpretations have been widely shared with the public and the scientific community through web sites, frequent press releases, and scientific publications, and they provide quantitative evidence that liquid water has played a role in the modification of the Martian surface during the earliest part of the planet's history. At the Spirit site in Gusev Crater, the role of water appears to have been relatively minor in general, although the recent discovery of enigmatic hydrated sulfate salt and amorphous silica deposits suggests that locally there may have been significant water-rock interactions, and perhaps even sustained hydrothermal activity. At the Opportunity site in Meridiani Planum, geologic and mineralogic evidence suggests that liquid water was stable at the surface and shallow subsurface for significant periods of early Martian geologic history. An exciting implication from both missions is that localized environments on early Mars may have been "habitable" by some terrestrial standards. As of early September 2010, the rovers had operated for 2210 and 2347 Martian days (sols), respectively, with the Spirit

Non-Flow-Through Fuel Cell System Test Results and Demonstration on the SCARAB Rover

Science.gov (United States)

Scheidegger, Brianne, T.; Burke, Kenneth A.; Jakupca, Ian J.

2012-01-01

This paper describes the results of the demonstration of a non-flow-through PEM fuel cell as part of a power system on the SCARAB rover. A 16-cell non-flow-through fuel cell stack from Infinity Fuel Cell and Hydrogen, Inc. was incorporated into a power system designed to act as a range extender by providing power to the rover s hotel loads. This work represents the first attempt at a ground demonstration of this new technology aboard a mobile test platform. Development and demonstration were supported by the Office of the Chief Technologist s Space Power Systems Project and the Advanced Exploration System Modular Power Systems Project.

SEI power source alternatives for rovers and other multi-kWe distributed surface applications

Science.gov (United States)

Bents, David J.; Kohout, L. L.; Mckissock, Barbara I.; Rodriguez, C. D.; Withrow, C. A.; Colozza, A.; Hanlon, James C.; Schmitz, Paul C.

1991-01-01

To support the Space Exploration Initiative (SEI), a study was performed to investigate power system alternatives for the rover vehicles and servicers that were subsequently generated for each of these rovers and servicers, candidate power sources incorporating various power generation and energy storage technologies were identified. The technologies were those believed most appropriate to the SEI missions, and included solar, electrochemical, and isotope systems. The candidates were characterized with respect to system mass, deployed area, and volume. For each of the missions a preliminary selection was made. Results of this study depict the available power sources in light of mission requirements as they are currently defined.

Maps of the Martian Landing Sites and Rover Traverses: Viking 1 and 2, Mars Pathfinder, and Phoenix Landers, and the Mars Exploration Rovers.

Science.gov (United States)

Parker, T. J.; Calef, F. J., III; Deen, R. G.; Gengl, H.

2016-12-01

The traverse maps produced tactically for the MER and MSL rover missions are the first step in placing the observations made by each vehicle into a local and regional geologic context. For the MER, Phoenix and MSL missions, 25cm/pixel HiRISE data is available for accurately localizing the vehicles. Viking and Mars Pathfinder, however, relied on Viking Orbiter images of several tens of m/pixel to triangulate to horizon features visible both from the ground and from orbit. After Pathfinder, MGS MOC images became available for these landing sites, enabling much better correlations to horizon features and localization predictions to be made, that were then corroborated with HiRISE images beginning 9 years ago. By combining topography data from MGS, Mars Express, and stereo processing of MRO CTX and HiRISE images into orthomosaics (ORRs) and digital elevation models (DEMs), it is possible to localize all the landers and rover positions to an accuracy of a few tens of meters with respect to the Mars global control net, and to better than half a meter with respect to other features within a HiRISE orthomosaic. JPL's MIPL produces point clouds of the MER Navcam stereo images that can be processed into 1cm/pixel ORR/DEMs that are then georeferenced to a HiRISE/CTX base map and DEM. This allows compilation of seamless mosaics of the lander and rover camera-based ORR/DEMs with the HiRISE ORR/DEM that can be viewed in 3 dimensions with GIS programs with that capability. We are re-processing the Viking Lander, Mars Pathfinder, and Phoenix lander data to allow similar ORR/DEM products to be made for those missions. For the fixed landers and Spirit, we will compile merged surface/CTX/HiRISE ORR/DEMs, that will enable accurate local and regional mapping of these landing sites, and allow comparisons of the results from these missions to be made with current and future surface missions.

Pancam and Microscopic Imager observations of dust on the Spirit Rover: Cleaning events, spectral properties, and aggregates

Science.gov (United States)

Vaughan, Alicia F.; Johnson, Jeffrey R.; Herkenhoff, Kenneth E.; Sullivan, Robert; Landis, Geoffrey A.; Goetz, Walter; Madsen, Morten B.

2010-01-01

This work describes dust deposits on the Spirit Rover over 2000 sols through examination of Pancam and Microscopic Imager observations of specific locations on the rover body, including portions of the solar array, Pancam and Mini-TES calibration targets, and the magnets. This data set reveals the three "cleaning events" experienced by Spirit to date, the spectral properties of dust, and the tendency of dust particles to form aggregates 100 um and larger.

Simulations of the magnetic properties experiment on Mars Exploration Rovers

International Nuclear Information System (INIS)

Gunnlaugsson, H. P.; Worm, E. S.; Bertelsen, P.; Goetz, W.; Kinch, K.; Madsen, M. B.; Merrison, J. P.; Nornberg, P.

2005-01-01

We present some of the main findings from simulation studies of the Magnetic Properties Experiment on the Mars Exploration Rovers. The results suggest that the dust has formed via mechanical breakdown of surface rocks through the geological history of the planet, and that liquid water need not have played any significant role in the dust formation processes.

Martian methane plume models for defining Mars rover methane source search strategies

Science.gov (United States)

Nicol, Christopher; Ellery, Alex; Lynch, Brian; Cloutis, Ed

2018-07-01

The detection of atmospheric methane on Mars implies an active methane source. This introduces the possibility of a biotic source with the implied need to determine whether the methane is indeed biotic in nature or geologically generated. There is a clear need for robotic algorithms which are capable of manoeuvring a rover through a methane plume on Mars to locate its source. We explore aspects of Mars methane plume modelling to reveal complex dynamics characterized by advection and diffusion. A statistical analysis of the plume model has been performed and compared to analyses of terrestrial plume models. Finally, we consider a robotic search strategy to find a methane plume source. We find that gradient-based techniques are ineffective, but that more sophisticated model-based search strategies are unlikely to be available in near-term rover missions.

Paleo-environmental Setting of the Murray Formation of Aeolis Mons, Gale Crater, Mars, as Explored by the Curiosity Rover

Science.gov (United States)

Lewis, K. W.; Fedo, C.; Grotzinger, J. P.; Gupta, S.; Stein, N.; Rivera-Hernandez, F.; Watkins, J. A.; Banham, S.; Edgett, K. S.; Minitti, M. E.; Schieber, J.; Edgar, L. A.; Siebach, K. L.; Stack, K.; Newsom, H. E.; House, C. H.; Sumner, D. Y.; Vasavada, A. R.

2017-12-01

Since landing, the Mars Science Laboratory Curiosity rover climbed 300 meters in elevation from the floor of north Gale crater up the lower northwest flank of Aeolis Mons ("Mount Sharp"). Nearly 200 meters of this ascent was accomplished in the 1.5 years alone, as the rover was driven up-section through the sedimentary rocks of the informally designated "Murray" formation. This unit comprises a large fraction of the lower strata of Mt. Sharp along the rover traverse. Our exploration of the Murray formation reveals a diverse suite of fine-grained facies. Grain sizes range from finer grains than can be resolved by the MAHLI imager (particles bearing Vera Rubin Ridge, continues to reveal the complex and long-lived depositional history of the Gale crater basin.

77 FR 21734 - Certain Small Diameter Carbon and Alloy Seamless Standard, Line, and Pressure Pipe From Romania...

Science.gov (United States)

2012-04-11

... DEPARTMENT OF COMMERCE International Trade Administration [A-485-805] Certain Small Diameter Carbon and Alloy Seamless Standard, Line, and Pressure Pipe From Romania: Extension of Time Limit for... diameter carbon and alloy seamless standard, line and pressure pipe from Romania for the period August 1...

Techniques of Force and Pressure Measurement in the Small Joints of the Wrist.

Science.gov (United States)

Schreck, Michael J; Kelly, Meghan; Canham, Colin D; Elfar, John C

2018-01-01

The alteration of forces across joints can result in instability and subsequent disability. Previous methods of force measurements such as pressure-sensitive films, load cells, and pressure-sensing transducers have been utilized to estimate biomechanical forces across joints and more recent studies have utilized a nondestructive method that allows for assessment of joint forces under ligamentous restraints. A comprehensive review of the literature was performed to explore the numerous biomechanical methods utilized to estimate intra-articular forces. Methods of biomechanical force measurements in joints are reviewed. Methods such as pressure-sensitive films, load cells, and pressure-sensing transducers require significant intra-articular disruption and thus may result in inaccurate measurements, especially in small joints such as those within the wrist and hand. Non-destructive methods of joint force measurements either utilizing distraction-based joint reaction force methods or finite element analysis may offer a more accurate assessment; however, given their recent inception, further studies are needed to improve and validate their use.

The Geologic Exploration of the Bagnold Dune Field at Gale Crater by the Curiosity Rover.

Science.gov (United States)

Chojnacki, Matthew; Fenton, Lori K

2017-11-01

The Mars Science Laboratory rover Curiosity engaged in a monthlong campaign investigating the Bagnold dune field in Gale crater. What represents the first in situ investigation of a dune field on another planet has resulted in a number of discoveries. Collectively, the Curiosity rover team has compiled the most comprehensive survey of any extraterrestrial aeolian system visited to date with results that yield important insights into a number of processes, including sediment transport, bed form morphology and structure, chemical and physical composition of aeolian sand, and wind regime characteristics. These findings and more are provided in detail by the JGR-Planets Special Issue Curiosity's Bagnold Dunes Campaign, Phase I.

Autonomous Vision-Based Tethered-Assisted Rover Docking

Science.gov (United States)

Tsai, Dorian; Nesnas, Issa A.D.; Zarzhitsky, Dimitri

2013-01-01

Many intriguing science discoveries on planetary surfaces, such as the seasonal flows on crater walls and skylight entrances to lava tubes, are at sites that are currently inaccessible to state-of-the-art rovers. The in situ exploration of such sites is likely to require a tethered platform both for mechanical support and for providing power and communication. Mother/daughter architectures have been investigated where a mother deploys a tethered daughter into extreme terrains. Deploying and retracting a tethered daughter requires undocking and re-docking of the daughter to the mother, with the latter being the challenging part. In this paper, we describe a vision-based tether-assisted algorithm for the autonomous re-docking of a daughter to its mother following an extreme terrain excursion. The algorithm uses fiducials mounted on the mother to improve the reliability and accuracy of estimating the pose of the mother relative to the daughter. The tether that is anchored by the mother helps the docking process and increases the system's tolerance to pose uncertainties by mechanically aligning the mating parts in the final docking phase. A preliminary version of the algorithm was developed and field-tested on the Axel rover in the JPL Mars Yard. The algorithm achieved an 80% success rate in 40 experiments in both firm and loose soils and starting from up to 6 m away at up to 40 deg radial angle and 20 deg relative heading. The algorithm does not rely on an initial estimate of the relative pose. The preliminary results are promising and help retire the risk associated with the autonomous docking process enabling consideration in future martian and lunar missions.

Mars Rover Model Celebration: Developing Inquiry Based Lesson Plans to Teach Planetary Science In Elementary And Middle School

Science.gov (United States)

Bering, E. A.; Slagle, E.; Nieser, K.; Carlson, C.; Kapral, A.; Dominey, W.; Ramsey, J.; Konstantinidis, I.; James, J.; Sweaney, S.; Mendez, R.

2012-12-01

The recent NASA Mars Rover missions capture the imagination of children, as NASA missions have done for decades. The University of Houston is in the process of developing a prototype of a flexible program that offers children an in-depth educational experience culminating in the design and construction of their own model rover. The existing prototype program is called the Mars Rover Model Celebration. It focuses on students, teachers and parents in grades 3-8. Students will design and build a model of a Mars rover to carry out a student selected science mission on the surface of Mars. The model will be a mock-up, constructed at a minimal cost from art supplies. The students will build the models as part of a project on Mars. The students will be given design criteria for a rover and will do basic research on Mars that will determine the objectives and features of their rover. This project may be used either informally as an after school club or youth group activity or formally as part of a class studying general science, earth science, solar system astronomy or robotics, or as a multi-disciplinary unit for a gifted and talented program. The project's unique strength lies in engaging students in the process of spacecraft design and interesting them in aerospace engineering careers. The project is aimed at elementary and secondary education. Not only will these students learn about scientific fields relevant to the mission (space science, physics, geology, robotics, and more), they will gain an appreciation for how this knowledge is used to tackle complex problems. The low cost of the event makes it an ideal enrichment vehicle for low income schools. It provides activities that provide professional development to educators, curricular support resources using NASA Science Mission Directorate (SMD) content, and provides family opportunities for involvement in K-12 student learning. This paper will describe the development of a detailed set of new 5E lesson plans to

Habitability on Early Mars and the Search for Biosignatures with the ExoMars Rover

Science.gov (United States)

Vago, Jorge L.; Westall, Frances; Pasteur Instrument Team; Pasteur Landing Team; Coates, Andrew J.; Jaumann, Ralf; Korablev, Oleg; Ciarletti, Valérie; Mitrofanov, Igor; Josset, Jean-Luc; De Sanctis, Maria Cristina; Bibring, Jean-Pierre; Rull, Fernando; Goesmann, Fred; Steininger, Harald; Goetz, Walter; Brinckerhoff, William; Szopa, Cyril; Raulin, François; Westall, Frances; Edwards, Howell G. M.; Whyte, Lyle G.; Fairén, Alberto G.; Bibring, Jean-Pierre; Bridges, John; Hauber, Ernst; Ori, Gian Gabriele; Werner, Stephanie; Loizeau, Damien; Kuzmin, Ruslan O.; Williams, Rebecca M. E.; Flahaut, Jessica; Forget, François; Vago, Jorge L.; Rodionov, Daniel; Korablev, Oleg; Svedhem, Håkan; Sefton-Nash, Elliot; Kminek, Gerhard; Lorenzoni, Leila; Joudrier, Luc; Mikhailov, Viktor; Zashchirinskiy, Alexander; Alexashkin, Sergei; Calantropio, Fabio; Merlo, Andrea; Poulakis, Pantelis; Witasse, Olivier; Bayle, Olivier; Bayón, Silvia; Meierhenrich, Uwe; Carter, John; García-Ruiz, Juan Manuel; Baglioni, Pietro; Haldemann, Albert; Ball, Andrew J.; Debus, André; Lindner, Robert; Haessig, Frédéric; Monteiro, David; Trautner, Roland; Voland, Christoph; Rebeyre, Pierre; Goulty, Duncan; Didot, Frédéric; Durrant, Stephen; Zekri, Eric; Koschny, Detlef; Toni, Andrea; Visentin, Gianfranco; Zwick, Martin; van Winnendael, Michel; Azkarate, Martín; Carreau, Christophe; ExoMars Project Team

2017-07-01

The second ExoMars mission will be launched in 2020 to target an ancient location interpreted to have strong potential for past habitability and for preserving physical and chemical biosignatures (as well as abiotic/prebiotic organics). The mission will deliver a lander with instruments for atmospheric and geophysical investigations and a rover tasked with searching for signs of extinct life. The ExoMars rover will be equipped with a drill to collect material from outcrops and at depth down to 2 m. This subsurface sampling capability will provide the best chance yet to gain access to chemical biosignatures. Using the powerful Pasteur payload instruments, the ExoMars science team will conduct a holistic search for traces of life and seek corroborating geological context information.

Mars' surface radiation environment measured with the Mars science laboratory's curiosity rover

NARCIS (Netherlands)

Hassler, D.M.; Zeitlin, C.; Wimmer-Schweingruber, R.F.; Ehresmann, B.; Rafkin, S.; Eigenbrode, J.L.; Brinza, D.E.; Weigle, G.; Böttcher, S.; Böhm, E.; Burmeister, S.; Guo, J.; Köhler, J.; Martin, C.; Reitz, G.; Cucinotta, F.A.; Kim, M.-H.; Grinspoon, D.; Bullock, M.A.; Posner, A.; Gómez-Elvira, J.; Vasavada, A.; Grotzinger, J.P.; MSL Science Team, the|info:eu-repo/dai/nl/292012217

2014-01-01

The Radiation Assessment Detector (RAD) on the Mars Science Laboratory’s Curiosity rover began making detailed measurements of the cosmic ray and energetic particle radiation environment on the surface of Mars on 7 August 2012. We report and discuss measurements of the absorbed dose and dose

Impact of pressure losses in small-sized parabolic-trough collectors for direct steam generation

International Nuclear Information System (INIS)

Lobón, David H.; Valenzuela, Loreto

2013-01-01

Using PTC (parabolic-trough solar collectors) for industrial thermal processes in the temperature range up to 300 °C is not new, but in recent years there is a boosted interest in this type of concentrating solar technology. One of the problems that arise when designing PTC solar fields is how to deal with the pressure losses which are critical when producing saturated steam directly in the collectors. Depending on the characteristics of the collector, mainly on the receiver diameter, and on the nominal process conditions defined, a solar field configuration can be feasible or not. This paper presents a sensitivity analysis done using a software tool developed to study the thermo-hydraulic behaviour of PTC systems using water-steam as heat transfer fluid. In the case study presented, a small-sized PTC designed for industrial process heat applications is considered, which has a focal length of 0.2 m, an aperture area of 2 m 2 , and its receiver pipe has an inner diameter of 15 mm. Varied process conditions are inlet water pressure, temperature, and mass flow rate, solar irradiance and incidence angle of solar radiation. Results show that working pressure definition is particularly critical to make feasible or not the direct steam generation in solar collectors. - Highlights: • DSG (Direct steam generation) in small-sized parabolic-trough collectors. • Thermo-hydraulic sensitivity analysis. • Influence of working pressure and receiver geometry in DSG process

Preface: The Chang'e-3 lander and rover mission to the Moon

Science.gov (United States)

Ip, Wing-Huen; Yan, Jun; Li, Chun-Lai; Ouyang, Zi-Yuan

2014-12-01

The Chang'e-3 (CE-3) lander and rover mission to the Moon was an intermediate step in China's lunar exploration program, which will be followed by a sample return mission. The lander was equipped with a number of remote-sensing instruments including a pair of cameras (Landing Camera and Terrain Camera) for recording the landing process and surveying terrain, an extreme ultraviolet camera for monitoring activities in the Earth's plasmasphere, and a first-ever Moon-based ultraviolet telescope for astronomical observations. The Yutu rover successfully carried out close-up observations with the Panoramic Camera, mineralogical investigations with the VIS-NIR Imaging Spectrometer, study of elemental abundances with the Active Particle-induced X-ray Spectrometer, and pioneering measurements of the lunar subsurface with Lunar Penetrating Radar. This special issue provides a collection of key information on the instrumental designs, calibration methods and data processing procedures used by these experiments with a perspective of facilitating further analyses of scientific data from CE-3 in preparation for future missions.

Atmospheric-pressure small-scale thermal-hydraulic experiment of a PIUS-type reactor

International Nuclear Information System (INIS)

Tasaka, Kanji; Tamaki, Masayoshi; Imai, Satoshi; Kohketsu, Hideto; Anoda, Yoshinari; Murata, Hideo; Kukita, Yutaka.

1992-01-01

An experimental small-scale low-pressure setup of a PIUS (Process Inherent Ultimate Safety)-type reactor was used for the examination of the stability during normal operation such as startup and load following operation and of the safety during accidents such as loss-of-feedwater and pump runaway. Automatic feedback pump control system based on differential pressure at lower honeycomb density lock was quite effective to maintain the stratified interface between primary and pool water in the honeycomb density lock during normal operation. The process inherent ultimate safety characteristics of the PIUS-type reactor was confirmed with pump-trip scram at the pump speed limit for the various simulated accidents such as a loss-of-feedwater and pump runaway. (author)

Internal helical modes with m > 1 in a tokamak with a small shear and high plasma pressure

International Nuclear Information System (INIS)

Mikha lovskij, A.B.; Aburdzhaniya, G.D.; Krymskij, A.M.

1979-01-01

Internal helical modes with m>1 in a circular cross-section tokamak with a small shear and large value of the parameter β (β is the ratio between the mean plasma pressure and the mean pressure of the poloidal magnetic field) are investigated. The equations obtained are used to study the destabilizing effects leading to helical instabilities. The role of destabilizing effects is regarded both in local and in a nonlocal approximations on the assumption that the radial plasma pressure is distributed parabolically and that the radial current distribution is also parabolic though slightly varying. It has been established that the profiling of current may lead to the tokamak plasma stability with respect to the modes under investigation. A tokamak with a small shear has been shown to be more stable relative to these modes than that with a large shear

Influence of operating conditions and atomizer design on circumferential liquid distribution from small pressure-swirl atomizer

Science.gov (United States)

Malý, Milan; Janáčková, Lada; Jedelský, Jan; Jícha, Miroslav

The spray symmetry is an important aspect in most practical applications. However, it is often an overlooked parameter. A measurement of circumferential distribution was carried out by a circular-sectored vessel on several pressure-swirl atomizers with spill-line over a wide range of injection pressure. The obtained results show that the spray uniformity improves markedly with the injection pressure. The increase in a number of tangential entry ports has only a minor effect on the spray uniformity. Even a small mechanical corruption of the atomizer internal parts negatively affects the spray patternation.

Small-angle neutron scattering study of high-pressure sintered detonation nanodiamonds

Energy Technology Data Exchange (ETDEWEB)

Kidalov, S. V.; Shakhov, F. M., E-mail: fedor.shakhov@mail.ioffe.ru [Ioffe Physical-Technical Institute of the Russian Academy of Sciences (Russian Federation); Lebedev, V. T.; Orlova, D. N.; Grushko, Yu. S. [Russian Academy of Sciences, Konstantinov St. Petersburg Nuclear Physics Institute (Russian Federation)

2011-12-15

The structure of detonation diamonds sintered at a high pressure (7 GPa) and temperatures of 1200-1700 Degree-Sign C has been investigated by small-angle neutron scattering. It is shown that sintering leads to an increase in the particle size from 6 to 30 nm and established that this increase is due to the chainlike oriented attachment of particles. This study supplements the oriented-attachment model, which was suggested based on the X-ray diffraction spectra of detonation nanodiamonds (DNDs) sintered under the same conditions.

Preliminary Dynamic Feasibility and Analysis of a Spherical, Wind-Driven (Tumbleweed), Martian Rover

Science.gov (United States)

Flick, John J.; Toniolo, Matthew D.

2005-01-01

The process and findings are presented from a preliminary feasibility study examining the dynamics characteristics of a spherical wind-driven (or Tumbleweed) rover, which is intended for exploration of the Martian surface. The results of an initial feasibility study involving several worst-case mobility situations that a Tumbleweed rover might encounter on the surface of Mars are discussed. Additional topics include the evaluation of several commercially available analysis software packages that were examined as possible platforms for the development of a Monte Carlo Tumbleweed mission simulation tool. This evaluation lead to the development of the Mars Tumbleweed Monte Carlo Simulator (or Tumbleweed Simulator) using the Vortex physics software package from CM-Labs, Inc. Discussions regarding the development and evaluation of the Tumbleweed Simulator, as well as the results of a preliminary analysis using the tool are also presented. Finally, a brief conclusions section is presented.

Data Processing and Primary results of Lunar Penetrating Radar on Board the Chinese Yutu Rover

Science.gov (United States)

Su, Yan; Xing, Shuguo; Feng, Jianqing; Dai, Shun; Ding, Chunyu; Xiao, Yuan; Zhang, Hongbo; Zhao, Shu; Xue, Xiping; Zhang, Xiaoxia; Liu, Bin; Yao, Meijuan; Li, Chunlai

2015-04-01

Radar is an attractive and powerful technique to observe the Moon. Radar mapping of the Moon's topography was first done by the Arecibo telescope at a wave- length of 70 cm in 1964 (Thompson & Dyce 1966). Chang'e-3 (CE-3) was successfully launched on 2013 December 2, and the landing place is in Mare Imbrium, about 40km south of the 6km diameter Laplace F crater, at 44.1214ON, 19.5116OW. The Lunar ground-Penetrating Radar (LPR) is one of scientific payloads of the Yutu rover, aiming to achieve the first direct measurements and explore the lunar subsurface structure. Compared with ALSE and LRS, LPR works at higher frequencies of 60 MHz and 500 MHz. Thus it can probe regions with shallower depth including the regolith and lunar crust at higher range resolution. The LPR uses one transmitting and one receiving dipole antenna for 60 MHz which are installed at the back of the rover. For 500 MHz, one transmitting and two bow-tie receiving antennas are attached to the bottom of the rover. It transmits a pulsed signal and receives the radar echo signal along the path that the Yutu rover traverses. The free space range resolutions are ~ 50 cm and ~ 25 m for 60 MHz and 500 MHz respectively. The radar data stop being sampled and are sent back to Earth when Yutu is stationary. Observations are simultaneously carried out at frequencies of 60 MHz and 500 MHz. Since the Yutu rover had severe problems during its second lunar day, it is pity that the Yutu rover only transversed a limited distance of 114.8m. In total, 566 MB of data were obtained. The scientific data are archived and distributed by National Astronomical Observatories, Chinese Academy of Sciences. Data processing has been done in order to eliminate the effect of the instrument. To obtain clear radar images, more data processing need to be applied such as coordinate transformation, data editing, background removal, the operations of smoothing and gain resetting. The radar signal could detect hundreds of meters deep at

Design and analysis of throttle orifice applying to small space with large pressure drop

International Nuclear Information System (INIS)

Li Yan; Lu Daogang; Zeng Xiaokang

2013-01-01

Throttle orifices are widely used in various pipe systems of nuclear power plants. Improper placement of orifices would aggravate the vibration of the pipe with strong noise, damaging the structure of the pipe and the completeness of the system. In this paper, effects of orifice diameter, thickness, eccentric distance and chamfering on the throttling are analyzed applying CFD software. Based on that, we propose the throttle orifices which apply to small space with large pressure drop are multiple eccentric orifices. The results show that the multiple eccentric orifices can effectively restrain the cavitation and flash distillation, while generating a large pressure drop. (authors)

Mars Rover Model Celebration: Using Planetary Exploration To Enrich STEM Teaching In Elementary And Middle School

Science.gov (United States)

Bering, E. A.; Ramsey, J.; Dominey, W.; Kapral, A.; Carlson, C.; Konstantinidis, I.; James, J.; Sweaney, S.; Mendez, R.

2011-12-01

The present aerospace engineering and science workforce is ageing. It is not clear that the US education system will produce enough qualified replacements to meet the need in the near future. Unfortunately, by the time many students get to high school, it is often too late to get them pointed toward an engineering or science career. Since some college programs require 6 units of high school mathematics for admission, students need to begin consciously preparing for a science or engineering curriculum as early as 6th or 7th grade. The challenge for educators is to convince elementary school students that science and engineering are both exciting, relevant and accessible career paths. The recent NASA Mars Rover missions capture the imagination of children, as NASA missions have done for decades. The University of Houston is in the process of developing a prototype of a flexible program that offers children an in-depth educational experience culminating in the design and construction of their own model rover. The existing prototype program is called the Mars Rover Model Celebration. It focuses on students, teachers and parents in grades 3-8. Students will design and build a model of a Mars rover to carry out a student selected science mission on the surface of Mars. The model will be a mock-up, constructed at a minimal cost from art supplies. The students will build the models as part of a project on Mars. The students will be given design criteria for a rover and will do basic research on Mars that will determine the objectives and features of their rover. This project may be used either informally as an after school club or youth group activity or formally as part of a class studying general science, earth science, solar system astronomy or robotics, or as a multi-disciplinary unit for a gifted and talented program. The program culminates in a capstone event held at the University of Houston (or other central location in the other communities that will be involved

Influence of operating conditions and atomizer design on circumferential liquid distribution from small pressure-swirl atomizer

Directory of Open Access Journals (Sweden)

Malý Milan

2017-01-01

Full Text Available The spray symmetry is an important aspect in most practical applications. However, it is often an overlooked parameter. A measurement of circumferential distribution was carried out by a circular-sectored vessel on several pressure-swirl atomizers with spill-line over a wide range of injection pressure. The obtained results show that the spray uniformity improves markedly with the injection pressure. The increase in a number of tangential entry ports has only a minor effect on the spray uniformity. Even a small mechanical corruption of the atomizer internal parts negatively affects the spray patternation.

Effects of pressure and temperature on pore structure of ceramic synthesized from rice husk: A small angle neutron scattering investigation

Energy Technology Data Exchange (ETDEWEB)

Raut Dessai, R., E-mail: reshooin@yahoo.com [Department of Physics, Goa University, Taleigao Plateau, Goa 403 206 (India); Desa, J.A.E. [Department of Physics, Goa University, Taleigao Plateau, Goa 403 206 (India); Sen, D.; Mazumder, S. [Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

2013-07-05

Highlights: ► A porous ceramic has been prepared from silica obtained from rice husk. ► The ceramic has a hierarchical pore structure from micrometric to nano-metric. ► Small Angle Neutron Scattering data indicate nano-pore connectivity to micro-pores. ► Pore morphology can be tuned by compaction pressure and sintering temperature. -- Abstract: Ceramic powder has been synthesized from rice husk as the source of silica. In order to probe the evolution of its hierarchical mesoscopic and microscopic porous structure, the ceramic powder was compacted at different pressures and was sintered at different temperatures. A glassy ceramic to crystalline transition under thermal treatment (up to 1000 °C) was revealed by X-ray diffraction. Existence of pores in two widely separated length scales was indicated by small angle neutron scattering with the smaller ones having mass fractal arrangement. Although no significant change in small pore structure under thermal effect was indicated, a significant modification of the same has been revealed by small angle neutron scattering at different compaction pressures. Connectivity between the pores was ascertained from scattering experiments on the ceramic compact impregnated with heavy water. Scanning electron microscopy shows the microstructure to undergo appreciable coalescence of micrometric ceramic particles for sintering temperature and pressure changes.

Data Management for Mars Exploration Rovers

Science.gov (United States)

Snyder, Joseph F.; Smyth, David E.

2004-01-01

Data Management for the Mars Exploration Rovers (MER) project is a comprehensive system addressing the needs of development, test, and operations phases of the mission. During development of flight software, including the science software, the data management system can be simulated using any POSIX file system. During testing, the on-board file system can be bit compared with files on the ground to verify proper behavior and end-to-end data flows. During mission operations, end-to-end accountability of data products is supported, from science observation concept to data products within the permanent ground repository. Automated and human-in-the-loop ground tools allow decisions regarding retransmitting, re-prioritizing, and deleting data products to be made using higher level information than is available to a protocol-stack approach such as the CCSDS File Delivery Protocol (CFDP).

Methods and decision making on a Mars rover for identification of fossils

Science.gov (United States)

Eberlein, Susan; Yates, Gigi

1989-01-01

A system for automated fusion and interpretation of image data from multiple sensors, including multispectral data from an imaging spectrometer is being developed. Classical artificial intelligence techniques and artificial neural networks are employed to make real time decision based on current input and known scientific goals. Emphasis is placed on identifying minerals which could indicate past life activity or an environment supportive of life. Multispectral data can be used for geological analysis because different minerals have characteristic spectral reflectance in the visible and near infrared range. Classification of each spectrum into a broad class, based on overall spectral shape and locations of absorption bands is possible in real time using artificial neural networks. The goal of the system is twofold: multisensor and multispectral data must be interpreted in real time so that potentially interesting sites can be flagged and investigated in more detail while the rover is near those sites; and the sensed data must be reduced to the most compact form possible without loss of crucial information. Autonomous decision making will allow a rover to achieve maximum scientific benefit from a mission. Both a classical rule based approach and a decision neural network for making real time choices are being considered. Neural nets may work well for adaptive decision making. A neural net can be trained to work in two steps. First, the actual input state is mapped to the closest of a number of memorized states. After weighing the importance of various input parameters, the net produces an output decision based on the matched memory state. Real time, autonomous image data analysis and decision making capabilities are required for achieving maximum scientific benefit from a rover mission. The system under development will enhance the chances of identifying fossils or environments capable of supporting life on Mars

A Lab-on-Chip Design for Miniature Autonomous Bio-Chemoprospecting Planetary Rovers

Science.gov (United States)

Santoli, S.

The performance of the so-called ` Lab-on-Chip ' devices, featuring micrometre size components and employed at present for carrying out in a very fast and economic way the extremely high number of sequence determinations required in genomic analyses, can be largely improved as to further size reduction, decrease of power consumption and reaction efficiency through development of nanofluidics and of nano-to-micro inte- grated systems. As is shown, such new technologies would lead to robotic, fully autonomous, microwatt consumption and complete ` laboratory on a chip ' units for accurate, fast and cost-effective astrobiological and planetary exploration missions. The theory and the manufacturing technologies for the ` active chip ' of a miniature bio/chemoprospecting planetary rover working on micro- and nanofluidics are investigated. The chip would include micro- and nanoreactors, integrated MEMS (MicroElectroMechanical System) components, nanoelectronics and an intracavity nanolaser for highly accurate and fast chemical analysis as an application of such recently introduced solid state devices. Nano-reactors would be able to strongly speed up reaction kinetics as a result of increased frequency of reactive collisions. The reaction dynamics may also be altered with respect to standard macroscopic reactors. A built-in miniature telemetering unit would connect a network of other similar rovers and a central, ground-based or orbiting control unit for data collection and transmission to an Earth-based unit through a powerful antenna. The development of the ` Lab-on-Chip ' concept for space applications would affect the economy of space exploration missions, as the rover's ` Lab-on-Chip ' development would link space missions with the ever growing terrestrial market and business concerning such devices, largely employed in modern genomics and bioinformatics, so that it would allow the recoupment of space mission costs.

Conceptual Design and Dynamics Testing and Modeling of a Mars Tumbleweed Rover

Science.gov (United States)

Calhoun Philip C.; Harris, Steven B.; Raiszadeh, Behzad; Zaleski, Kristina D.

2005-01-01

The NASA Langley Research Center has been developing a novel concept for a Mars planetary rover called the Mars Tumbleweed. This concept utilizes the wind to propel the rover along the Mars surface, bringing it the potential to cover vast distances not possible with current Mars rover technology. This vehicle, in its deployed configuration, must be large and lightweight to provide the ratio of drag force to rolling resistance necessary to initiate motion from rest on the Mars surface. One Tumbleweed design concept that satisfies these considerations is called the Eggbeater-Dandelion. This paper describes the basic design considerations and a proposed dynamics model of the concept for use in simulation studies. It includes a summary of rolling/bouncing dynamics tests that used videogrammetry to better understand, characterize, and validate the dynamics model assumptions, especially the effective rolling resistance in bouncing/rolling dynamic conditions. The dynamics test used cameras to capture the motion of 32 targets affixed to a test article s outer structure. Proper placement of the cameras and alignment of their respective fields of view provided adequate image resolution of multiple targets along the trajectory as the test article proceeded down the ramp. Image processing of the frames from multiple cameras was used to determine the target positions. Position data from a set of these test runs was compared with results of a three dimensional, flexible dynamics model. Model input parameters were adjusted to match the test data for runs conducted. This process presented herein provided the means to characterize the dynamics and validate the simulation of the Eggbeater-Dandelion concept. The simulation model was used to demonstrate full scale Tumbleweed motion from a stationary condition on a flat-sloped terrain using representative Mars environment parameters.

Habitability on Early Mars and the Search for Biosignatures with the ExoMars Rover

Science.gov (United States)

Westall, Frances; Coates, Andrew J.; Jaumann, Ralf; Korablev, Oleg; Ciarletti, Valérie; Mitrofanov, Igor; Josset, Jean-Luc; De Sanctis, Maria Cristina; Bibring, Jean-Pierre; Goesmann, Fred; Steininger, Harald; Brinckerhoff, William; Szopa, Cyril; Raulin, François; Westall, Frances; Edwards, Howell G. M.; Whyte, Lyle G.; Fairén, Alberto G.; Bibring, Jean-Pierre; Bridges, John; Hauber, Ernst; Ori, Gian Gabriele; Werner, Stephanie; Loizeau, Damien; Kuzmin, Ruslan O.; Williams, Rebecca M. E.; Flahaut, Jessica; Forget, François; Rodionov, Daniel; Korablev, Oleg; Svedhem, Håkan; Sefton-Nash, Elliot; Kminek, Gerhard; Lorenzoni, Leila; Joudrier, Luc; Mikhailov, Viktor; Zashchirinskiy, Alexander; Alexashkin, Sergei; Calantropio, Fabio; Merlo, Andrea; Poulakis, Pantelis; Witasse, Olivier; Bayle, Olivier; Bayón, Silvia; Meierhenrich, Uwe; Carter, John; García-Ruiz, Juan Manuel; Baglioni, Pietro; Haldemann, Albert; Ball, Andrew J.; Debus, André; Lindner, Robert; Haessig, Frédéric; Monteiro, David; Trautner, Roland; Voland, Christoph; Rebeyre, Pierre; Goulty, Duncan; Didot, Frédéric; Durrant, Stephen; Zekri, Eric; Koschny, Detlef; Toni, Andrea; Visentin, Gianfranco; Zwick, Martin; van Winnendael, Michel; Azkarate, Martín; Carreau, Christophe

2017-01-01

Abstract The second ExoMars mission will be launched in 2020 to target an ancient location interpreted to have strong potential for past habitability and for preserving physical and chemical biosignatures (as well as abiotic/prebiotic organics). The mission will deliver a lander with instruments for atmospheric and geophysical investigations and a rover tasked with searching for signs of extinct life. The ExoMars rover will be equipped with a drill to collect material from outcrops and at depth down to 2 m. This subsurface sampling capability will provide the best chance yet to gain access to chemical biosignatures. Using the powerful Pasteur payload instruments, the ExoMars science team will conduct a holistic search for traces of life and seek corroborating geological context information. Key Words: Biosignatures—ExoMars—Landing sites—Mars rover—Search for life. Astrobiology 17, 471–510.

Small surface wave discharge at atmospheric pressure

Energy Technology Data Exchange (ETDEWEB)

Kiss' ovski, Zh; Kolev, M; Ivanov, A; Lishev, St; Koleva, I, E-mail: kissov@phys.uni-sofia.b [Faculty of Physics, Sofia University, BG-1164 Sofia (Bulgaria)

2009-09-21

A small surface wave driven source produces plasma at atmospheric pressure. Microwave power at frequency 2.45 GHz is coupled with the source and a discharge is ignited at power levels below 10 W. The coaxial exciter of the surface waves has a length of 10 mm because its dielectric is a high permittivity discharge tube. The plasma source operates as a plasma jet in the case of plasma columns longer than the tube length. The source maintains stable plasma columns over a wide range of neutral gas flow and applied power in continuous and pulse regimes. An additional advantage of this source is the discharge self-ignition. An electron temperature of T{sub e} {approx} 1.9 eV and a density of n{sub e} {approx} 3.9 x 10{sup 14} cm{sup -3} are estimated by the probe diagnostics method. The emission spectra in the wavelength range 200-1000 nm under different experimental conditions are analysed and they prove the applicability of the source for analytical spectroscopy. The dependences of column length, reflected power and plasma parameters on the gas flow and the input power are discussed. (fast track communication)

The design and engineering of curiosity how the Mars Rover performs its job

CERN Document Server

Lakdawalla, Emily

2018-01-01

This book describes the most complex machine ever sent to another planet: Curiosity. It is a one-ton robot with two brains, seventeen cameras, six wheels, nuclear power, and a laser beam on its head. No one human understands how all of its systems and instruments work. This essential reference to the Curiosity mission explains the engineering behind every system on the rover, from its rocket-powered jetpack to its radioisotope thermoelectric generator to its fiendishly complex sample handling system. Its lavishly illustrated text explains how all the instruments work -- its cameras, spectrometers, sample-cooking oven, and weather station -- and describes the instruments' abilities and limitations. It tells you how the systems have functioned on Mars, and how scientists and engineers have worked around problems developed on a faraway planet: holey wheels and broken focus lasers. And it explains the grueling mission operations schedule that keeps the rover working day in and day out.   .

Effect of Pressure Anisotropy on the m = 1 Small Wavelength Modes in Z-Pinches

Science.gov (United States)

Faghihi, M.

1987-05-01

A generalization of Freidberg's perpendicular MHD model is used to investigate the effect of pressure anisotropy on the small wavelength internal kink (m = 1) mode instability in a Z-Pinch. A normal mode analysis of perturbed motion of an incompressible, collisionless and cylindrical plasma is performed. The stability criterion is (rΣB2)' = 0.

Achieved Blood Pressure and Outcomes in the Secondary Prevention of Small Subcortical Strokes Trial.

Science.gov (United States)

Odden, Michelle C; McClure, Leslie A; Sawaya, B Peter; White, Carole L; Peralta, Carmen A; Field, Thalia S; Hart, Robert G; Benavente, Oscar R; Pergola, Pablo E

2016-01-01

Studies suggest a J-shaped association between blood pressure and cardiovascular events in the setting of intensive systolic blood pressure control; whether there is a similar association with stroke remains less well established. The Secondary Prevention of Small Subcortical Strokes was a randomized trial to evaluate higher (130-149 mm Hg) versus lower (blood pressure targets in participants with recent lacunar infarcts. We evaluated the association of mean achieved blood pressure, 6 months after randomization, and recurrent stroke, major vascular events, and all-cause mortality. After a mean follow up of 3.7 years, there was a J-shaped association between achieved blood pressure and outcomes; the lowest risk was at ≈124 and 67 mm Hg systolic and diastolic blood pressure, respectively. For example, above a systolic blood pressure of 124 mm Hg, 1 standard deviation higher (11.1 mm Hg) was associated with increased mortality (adjusted hazard ratio: 1.9; 95% confidence interval: 1.4, 2.7), whereas below this level, this relationship was inverted (0.29; 0.10, 0.79), Pblood pressure of 67 mm Hg, a 1 standard deviation higher (8.2 mm Hg) was associated with an increased risk of stroke (2.2; 1.4, 3.6), whereas below this level, the association was in the opposite direction (0.34; 0.13, 0.89), P=0.02 for interaction. The lowest risk of all events occurred at a nadir of ≈120 to 128 mm Hg systolic blood pressure and 65 to 70 mm Hg diastolic blood pressure. Future studies should evaluate the impact of excessive blood pressure reduction, especially in older populations with preexisting vascular disease. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00059306. © 2015 American Heart Association, Inc.

Applying FastSLAM to Articulated Rovers

Science.gov (United States)

Hewitt, Robert Alexander

This thesis presents the navigation algorithms designed for use on Kapvik, a 30 kg planetary micro-rover built for the Canadian Space Agency; the simulations used to test the algorithm; and novel techniques for terrain classification using Kapvik's LIDAR (Light Detection And Ranging) sensor. Kapvik implements a six-wheeled, skid-steered, rocker-bogie mobility system. This warrants a more complicated kinematic model for navigation than a typical 4-wheel differential drive system. The design of a 3D navigation algorithm is presented that includes nonlinear Kalman filtering and Simultaneous Localization and Mapping (SLAM). A neural network for terrain classification is used to improve navigation performance. Simulation is used to train the neural network and validate the navigation algorithms. Real world tests of the terrain classification algorithm validate the use of simulation for training and the improvement to SLAM through the reduction of extraneous LIDAR measurements in each scan.

Autonomously generating operations sequences for a Mars Rover using AI-based planning

Science.gov (United States)

Sherwood, Rob; Mishkin, Andrew; Estlin, Tara; Chien, Steve; Backes, Paul; Cooper, Brian; Maxwell, Scott; Rabideau, Gregg

2001-01-01

This paper discusses a proof-of-concept prototype for ground-based automatic generation of validated rover command sequences from highlevel science and engineering activities. This prototype is based on ASPEN, the Automated Scheduling and Planning Environment. This Artificial Intelligence (AI) based planning and scheduling system will automatically generate a command sequence that will execute within resource constraints and satisfy flight rules.

Photometric Observations of Soils and Rocks at the Mars Exploration Rover Landing Sites

Science.gov (United States)

Johnson, J. R.; Arvidson, R. A.; Bell, J. F., III; Farrand, W.; Guinness, E.; Johnson, M.; Herkenhoff, K. E.; Lemmon, M.; Morris, R. V.; Seelos, F., IV

2005-01-01

The Panoramic Cameras (Pancam) on the Spirit and Opportunity Mars Exploration Rovers have acquired multispectral reflectance observations of rocks and soils at different incidence, emission, and phase angles that will be used for photometric modeling of surface materials. Phase angle coverage at both sites extends from approx. 0 deg. to approx. 155 deg.

Pressure and Humidity Measurements at the MSL Landing Site Supported by Modeling of the Atmospheric Conditions

Science.gov (United States)

Harri, A.; Savijarvi, H. I.; Schmidt, W.; Genzer, M.; Paton, M.; Kauhanen, J.; Atlaskin, E.; Polkko, J.; Kahanpaa, H.; Kemppinen, O.; Haukka, H.

2012-12-01

The Mars Science Laboratory (MSL) called Curiosity Rover landed safely on the Martian surface at the Gale crater on 6th August 2012. Among the MSL scientific objectives are investigations of the Martian environment that will be addressed by the Rover Environmental Monitoring Station (REMS) instrument. It will investigate habitability conditions at the Martian surface by performing a versatile set of environmental measurements including accurate observations of pressure and humidity of the Martian atmosphere. This paper describes the instrumental implementation of the MSL pressure and humidity measurement devices and briefly analyzes the atmospheric conditions at the Gale crater by modeling efforts using an atmospheric modeling tools. MSL humidity and pressure devices are based on proprietary technology of Vaisala, Inc. Humidity observations make use of Vaisala Humicap® relative humidity sensor heads and Vaisala Barocap® sensor heads are used for pressure observations. Vaisala Thermocap® temperature sensors heads are mounted in a close proximity of Humicap® and Barocap® sensor heads to enable accurate temperature measurements needed for interpretation of Humicap® and Barocap® readings. The sensor heads are capacitive. The pressure and humidity devices are lightweight and are based on a low-power transducer controlled by a dedicated ASIC. The transducer is designed to measure small capacitances in order of a few pF with resolution in order of 0.1fF (femtoFarad). The transducer design has a good spaceflight heritage, as it has been used in several previous missions, for example Mars mission Phoenix as well as the Cassini Huygens mission. The humidity device has overall dimensions of 40 x 25 x 55 mm. It weighs18 g, and consumes 15 mW of power. It includes 3 Humicap® sensor heads and 1 Thermocap®. The transducer electronics and the sensor heads are placed on a single multi-layer PCB protected by a metallic Faraday cage. The Humidity device has measurement range

The ChemCam Instrument Suite on the Mars Science Laboratory (MSL) Rover: Body Unit and Combined System Tests

International Nuclear Information System (INIS)

Wiens, Roger C.; Barraclough, Bruce; Barkley, Walter C.; Bender, Steve; Bernardin, John; Bultman, Nathan; Clanton, Robert C.; Clegg, Samuel; Delapp, Dorothea; Dingler, Robert; Enemark, Don; Flores, Mike; Hale, Thomas; Lanza, Nina; Lasue, Jeremie; Latino, Joseph; Little, Cynthia; Morrison, Leland; Nelson, Tony; Romero, Frank; Salazar, Steven; Stiglich, Ralph; Storms, Steven; Trujillo, Tanner; Ulibarri, Mike; Vaniman, David; Whitaker, Robert; Witt, James; Maurice, Sylvestre; Bouye, Marc; Cousin, Agnes; Cros, Alain; D'Uston, Claude; Forni, Olivier; Gasnault, Olivier; Kouach, Driss; Lasue, Jeremie; Pares, Laurent; Poitrasson, Franck; Striebig, Nicolas; Thocaven, Jean-Jacques; Saccoccio, Muriel; Perez, Rene; Bell, James F. III; Hays, Charles; Blaney, Diana; DeFlores, Lauren; Elliott, Tom; Kan, Ed; Limonadi, Daniel; Lindensmith, Chris; Miller, Ed; Reiter, Joseph W.; Roberts, Tom; Simmonds, John J.; Warner, Noah; Blank, Jennifer; Bridges, Nathan; Cais, Phillippe; Clark, Benton; Cremers, David; Dyar, M. Darby; Fabre, Cecile; Herkenhoff, Ken; Kirkland, Laurel; Landis, David; Langevin, Yves; Lanza, Nina; Newsom, Horton; Ollila, Ann; LaRocca, Frank; Ott, Melanie; Mangold, Nicolas; Manhes, Gerard; Mauchien, Patrick; Blank, Jennifer; McKay, Christopher; Mooney, Joe; Provost, Cheryl; Morris, Richard V.; Sautter, Violaine; Sautter, Violaine; Waterbury, Rob; Wong-Swanson, Belinda; Barraclough, Bruce; Bender, Steve; Vaniman, David

2012-01-01

The ChemCam instrument suite on the Mars Science Laboratory (MSL) rover Curiosity provides remote compositional information using the first laser-induced breakdown spectrometer (LIBS) on a planetary mission, and provides sample texture and morphology data using a remote micro-imager (RMI). Overall, ChemCam supports MSL with five capabilities: remote classification of rock and soil characteristics; quantitative elemental compositions including light elements like hydrogen and some elements to which LIBS is uniquely sensitive (e.g., Li, Be, Rb, Sr, Ba); remote removal of surface dust and depth profiling through surface coatings; context imaging; and passive spectroscopy over the 240-905 nm range. ChemCam is built in two sections: The mast unit, consisting of a laser, telescope, RMI, and associated electronics, resides on the rover's mast, and is described in a companion paper. ChemCam's body unit, which is mounted in the body of the rover, comprises an optical de-multiplexer, three spectrometers, detectors, their coolers, and associated electronics and data handling logic. Additional instrument components include a 6 m optical fiber which transfers the LIBS light from the telescope to the body unit, and a set of onboard calibration targets. ChemCam was integrated and tested at Los Alamos National Laboratory where it also underwent LIBS calibration with 69 geological standards prior to integration with the rover. Post-integration testing used coordinated mast and instrument commands, including LIBS line scans on rock targets during system-level thermal-vacuum tests. In this paper we describe the body unit, optical fiber, and calibration targets, and the assembly, testing, and verification of the instrument prior to launch. (authors)

Estimates of power requirements for a Manned Mars Rover powered by a nuclear reactor

Science.gov (United States)

Morley, Nicholas J.; El-Genk, Mohamed S.; Cataldo, Robert; Bloomfield, Harvey

1991-01-01

This paper assesses the power requirement for a Manned Mars Rover vehicle. Auxiliary power needs are fulfilled using a hybrid solar photovoltaic/regenerative fuel cell system, while the primary power needs are meet using an SP-100 type reactor. The primary electric power needs, which include 30-kW(e) net user power, depend on the reactor thermal power and the efficiency of the power conversion system. Results show that an SP-100 type reactor coupled to a Free Piston Stirling Engine yields the lowest total vehicle mass and lowest specific mass for the power system. The second lowest mass was for a SP-100 reactor coupled to a Closed Brayton Cycle using He/Xe as the working fluid. The specific mass of the nuclear reactor power system, including a man-rated radiation shield, ranged from 150-kg/kW(e) to 190-kg/KW(e) and the total mass of the Rover vehicle varied depend upon the cruising speed.

Preface: The Chang'e-3 lander and rover mission to the Moon

International Nuclear Information System (INIS)

Ip Wing-Huen; Yan Jun; Li Chun-Lai; Ouyang Zi-Yuan

2014-01-01

The Chang'e-3 (CE-3) lander and rover mission to the Moon was an intermediate step in China's lunar exploration program, which will be followed by a sample return mission. The lander was equipped with a number of remote-sensing instruments including a pair of cameras (Landing Camera and Terrain Camera) for recording the landing process and surveying terrain, an extreme ultraviolet camera for monitoring activities in the Earth's plasmasphere, and a first-ever Moon-based ultraviolet telescope for astronomical observations. The Yutu rover successfully carried out close-up observations with the Panoramic Camera, mineralogical investigations with the VIS-NIR Imaging Spectrometer, study of elemental abundances with the Active Particle-induced X-ray Spectrometer, and pioneering measurements of the lunar subsurface with Lunar Penetrating Radar. This special issue provides a collection of key information on the instrumental designs, calibration methods and data processing procedures used by these experiments with a perspective of facilitating further analyses of scientific data from CE-3 in preparation for future missions

Integrated Navigation System Design for Micro Planetary Rovers: Comparison of Absolute Heading Estimation Algorithms and Nonlinear Filtering

Science.gov (United States)

Ilyas, Muhammad; Hong, Beomjin; Cho, Kuk; Baeg, Seung-Ho; Park, Sangdeok

2016-01-01

This paper provides algorithms to fuse relative and absolute microelectromechanical systems (MEMS) navigation sensors, suitable for micro planetary rovers, to provide a more accurate estimation of navigation information, specifically, attitude and position. Planetary rovers have extremely slow speed (~1 cm/s) and lack conventional navigation sensors/systems, hence the general methods of terrestrial navigation may not be applicable to these applications. While relative attitude and position can be tracked in a way similar to those for ground robots, absolute navigation information is hard to achieve on a remote celestial body, like Moon or Mars, in contrast to terrestrial applications. In this study, two absolute attitude estimation algorithms were developed and compared for accuracy and robustness. The estimated absolute attitude was fused with the relative attitude sensors in a framework of nonlinear filters. The nonlinear Extended Kalman filter (EKF) and Unscented Kalman filter (UKF) were compared in pursuit of better accuracy and reliability in this nonlinear estimation problem, using only on-board low cost MEMS sensors. Experimental results confirmed the viability of the proposed algorithms and the sensor suite, for low cost and low weight micro planetary rovers. It is demonstrated that integrating the relative and absolute navigation MEMS sensors reduces the navigation errors to the desired level. PMID:27223293

An ultrasound-based liquid pressure measurement method in small diameter pipelines considering the installation and temperature.

Science.gov (United States)

Li, Xue; Song, Zhengxiang

2015-04-09

Liquid pressure is a key parameter for detecting and judging faults in hydraulic mechanisms, but traditional measurement methods have many deficiencies. An effective non-intrusive method using an ultrasound-based technique to measure liquid pressure in small diameter (less than 15 mm) pipelines is presented in this paper. The proposed method is based on the principle that the transmission speed of an ultrasonic wave in a Kneser liquid correlates with liquid pressure. Liquid pressure was calculated using the variation of ultrasonic propagation time in a liquid under different pressures: 0 Pa and X Pa. In this research the time difference was obtained by an electrical processing approach and was accurately measured to the nanosecond level through a high-resolution time measurement module. Because installation differences and liquid temperatures could influence the measurement accuracy, a special type of circuit called automatic gain control (AGC) circuit and a new back propagation network (BPN) model accounting for liquid temperature were employed to improve the measurement results. The corresponding pressure values were finally obtained by utilizing the relationship between time difference, transient temperature and liquid pressure. An experimental pressure measurement platform was built and the experimental results confirm that the proposed method has good measurement accuracy.

Development of the science instrument CLUPI: the close-up imager on board the ExoMars rover

Science.gov (United States)

Josset, J.-L.; Beauvivre, S.; Cessa, V.; Martin, P.

2017-11-01

First mission of the Aurora Exploration Programme of ESA, ExoMars will demonstrate key flight and in situ enabling technologies, and will pursue fundamental scientific investigations. Planned for launch in 2013, ExoMars will send a robotic rover to the surface of Mars. The Close-UP Imager (CLUPI) instrument is part of the Pasteur Payload of the rover fixed on the robotic arm. It is a robotic replacement of one of the most useful instruments of the field geologist: the hand lens. Imaging of surfaces of rocks, soils and wind drift deposits at high resolution is crucial for the understanding of the geological context of any site where the Pasteur rover may be active on Mars. At the resolution provided by CLUPI (approx. 15 micrometer/pixel), rocks show a plethora of surface and internal structures, to name just a few: crystals in igneous rocks, sedimentary structures such as bedding, fracture mineralization, secondary minerals, details of the surface morphology, sedimentary bedding, sediment components, surface marks in sediments, soil particles. It is conceivable that even textures resulting from ancient biological activity can be visualized, such as fine lamination due to microbial mats (stromatolites) and textures resulting from colonies of filamentous microbes, potentially present in sediments and in palaeocavitites in any rock type. CLUPI is a complete imaging system, consisting of an APS (Active Pixel Sensor) camera with 27° FOV optics. The sensor is sensitive to light between 400 and 900 nm with 12 bits digitization. The fixed focus optics provides well focused images of 4 cm x 2.4 cm rock area at a distance of about 10 cm. This challenging camera system, less than 200g, is an independent scientific instrument linked to the rover on board computer via a SpaceWire interface. After the science goals and specifications presentation, the development of this complex high performance miniaturized imaging system will be described.

Scientific Results of the Mars Exploration Rovers Spirit and Opportunity

Science.gov (United States)

Banerdt, W. B.

2006-08-01

NASA's Mars Exploration Rover project launched two robotic geologists, Spirit and Opportunity, toward Mars in June and July of 2003, reaching Mars the following January. The science objectives for this mission are focused on delineating the geologic history for two locations on Mars, with an emphasis on the history of water. Although they were designed for a 90-day mission, both rovers have lasted more than two years on the surface and each has covered more than four miles while investigating Martian geology. Spirit was targeted to Gusev Crater, a 300-km diameter impact basin that was suspected to be the site of an ancient lake. Initial investigations of the plains in the vicinity of the landing site found no evidence of such a lake, but were instead consistent with unaltered (by water) basaltic plains. But after a 3-km trek to an adjacent range of hills it found a quite different situation, with abundant chemical and morphological evidence for a complex geological history. Opportunity has been exploring Meridiani Planum, which was known from orbital data to contain the mineral hematite, which generally forms in the presence of water. The rocks exposed in Meridiani are highly chemically altered, and appear to have been exposed to significant amounts of water. By descending into the 130-m diameter Endurance Crater, Opportunity was able to analyze a 10-m vertical section of this rock unit, which showed significant gradations in chemistry and morphology.

Blood Pressure Control in Aging Predicts Cerebral Atrophy Related to Small-Vessel White Matter Lesions

Directory of Open Access Journals (Sweden)

Kyle C. Kern

2017-05-01

Full Text Available Cerebral small-vessel damage manifests as white matter hyperintensities and cerebral atrophy on brain MRI and is associated with aging, cognitive decline and dementia. We sought to examine the interrelationship of these imaging biomarkers and the influence of hypertension in older individuals. We used a multivariate spatial covariance neuroimaging technique to localize the effects of white matter lesion load on regional gray matter volume and assessed the role of blood pressure control, age and education on this relationship. Using a case-control design matching for age, gender, and educational attainment we selected 64 participants with normal blood pressure, controlled hypertension or uncontrolled hypertension from the Northern Manhattan Study cohort. We applied gray matter voxel-based morphometry with the scaled subprofile model to (1 identify regional covariance patterns of gray matter volume differences associated with white matter lesion load, (2 compare this relationship across blood pressure groups, and (3 relate it to cognitive performance. In this group of participants aged 60–86 years, we identified a pattern of reduced gray matter volume associated with white matter lesion load in bilateral temporal-parietal regions with relative preservation of volume in the basal forebrain, thalami and cingulate cortex. This pattern was expressed most in the uncontrolled hypertension group and least in the normotensives, but was also more evident in older and more educated individuals. Expression of this pattern was associated with worse performance in executive function and memory. In summary, white matter lesions from small-vessel disease are associated with a regional pattern of gray matter atrophy that is mitigated by blood pressure control, exacerbated by aging, and associated with cognitive performance.

A Mars orbiter/rover/penetrator mission for the 1984 opportunity

Science.gov (United States)

Hastrup, R.; Driver, J.; Nagorski, R.

1977-01-01

A point design mission is described that utilizes the 1984 opportunity to extend the exploration of Mars after the successful Viking operations and provide the additional scientific information needed before conducting a sample return mission. Two identical multi-element spacecraft are employed, each consisting of (1) an orbiter, (2) a Viking-derived landing system that delivers a heavily instrumented, semi-autonomous rover, and (3) three penetrators deployed from the approach trajectory. Selection of the orbit profiles requires consideration of several important factors in order to satisfy all of the mission goals.

A systematic search of sudden pressure drops on Gale crater during two Martian years derived from MSL/REMS data

Science.gov (United States)

Ordonez-Etxeberria, Iñaki; Hueso, Ricardo; Sánchez-Lavega, Agustín

2018-01-01

The Mars Science Laboratory (MSL) rover carries a suite of meteorological detectors that constitute the Rover Environmental Monitoring Station (REMS) instrument. REMS investigates the meteorological conditions at Gale crater by obtaining high-frequency data of pressure, air and ground temperature, relative humidity, UV flux at the surface and wind intensity and direction with some limitations in the wind data. We have run a search of atmospheric pressure drops of short duration (pressure data during its first 1417 sols (more than two Martian years). The identified daytime pressure drops could be caused by the close passages of warm vortices and dust devils. Previous systematic searches of warm vortices from REMS pressure data (Kahanpää et al., 2016; Steakley and Murphy, 2016) cover about one Martian year. We show that sudden pressure drops are twice more abundant in the second Martian year [sols 671-1339] than in the first one analyzed in previous works. The higher number of detections could be linked to a combination of different topography, higher altitudes (120 m above the landing site) and true inter-annual meteorological variability. We found 1129 events with a pressure drop larger than 0.5 Pa. Of these, 635 occurred during the local daytime (∼56%) and 494 were nocturnal. The most intense pressure drop (4.2 Pa) occurred at daytime on sol 1417 (areocentric solar longitude Ls = 195°) and was accompanied by a simultaneous decrease in the UV signal of 7.1%, pointing to a true dust devil. We also discuss similar but less intense simultaneous pressure and UV radiation drops that constitute 0.7% of all daytime events. Most of the intense daytime pressure drops with variations larger than 1.0 Pa occur when the difference between air and ground temperature is larger than 15 K. Statistically, the frequency of daytime pressure drops peaks close to noon (12:00-13:00 Local True Solar Time or LTST) with more events in spring and summer (Ls from 180° to 360°). The

Cross-Coupled Control for All-Terrain Rovers

Directory of Open Access Journals (Sweden)

Giulio Reina

2013-01-01

Full Text Available Mobile robots are increasingly being used in challenging outdoor environments for applications that include construction, mining, agriculture, military and planetary exploration. In order to accomplish the planned task, it is critical that the motion control system ensure accuracy and robustness. The achievement of high performance on rough terrain is tightly connected with the minimization of vehicle-terrain dynamics effects such as slipping and skidding. This paper presents a cross-coupled controller for a 4-wheel-drive/4-wheel-steer robot, which optimizes the wheel motors’ control algorithm to reduce synchronization errors that would otherwise result in wheel slip with conventional controllers. Experimental results, obtained with an all-terrain rover operating on agricultural terrain, are presented to validate the system. It is shown that the proposed approach is effective in reducing slippage and vehicle posture errors.

Rover's Wheel Churns Up Bright Martian Soil

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Spirit acquired this mosaic on the mission's 1,202nd Martian day, or sol (May 21, 2007), while investigating the area east of the elevated plateau known as 'Home Plate' in the 'Columbia Hills.' The mosaic shows an area of disturbed soil, nicknamed 'Gertrude Weise' by scientists, made by Spirit's stuck right front wheel. The trench exposed a patch of nearly pure silica, with the composition of opal. It could have come from either a hot-spring environment or an environment called a fumarole, in which acidic, volcanic steam rises through cracks. Either way, its formation involved water, and on Earth, both of these types of settings teem with microbial life. Spirit acquired this mosaic with the panoramic camera's 753-nanometer, 535-nanometer, and 432-nanometer filters. The view presented here is an approximately true-color rendering.

Potential of Probing the Lunar Regolith using Rover-Mounted Ground Penetrating Radar: Moses Lake Dune Field Analog Study

Science.gov (United States)

Horz, F.; Heggy, E.; Fong, T.; Kring, D.; Deans, M.; Anglade, A.; Mahiouz, K.; Bualat, M.; Lee, P.; Bluethmann, W.

2009-01-01

Probing radars have been widely recognized by the science community to be an efficient tool to explore lunar subsurface providing a unique capability to address several scientific and operational issues. A wideband (200 to 1200 MHz) Ground Penetrating Radar (GPR) mounted on a surface rover can provide high vertical resolution and probing depth from few tens of centimeters to few tens of meters depending on the sounding frequency and the ground conductivity. This in term can provide a better understand regolith thickness, elemental iron concentration (including ilmenite), volatile presence, structural anomalies and fracturing. All those objectives are of important significance for understanding the local geology and potential sustainable resources for future landing sites in particular exploring the thickness, structural heterogeneity and potential volatiles presence in the lunar regolith. While the operation and data collection of GPR is a straightforward case for most terrestrial surveys, it is a challenging task for remote planetary study especially on robotic platforms due to the complexity of remote operation in rough terrains and the data collection constrains imposed by the mechanical motion of the rover and limitation in data transfer. Nevertheless, Rover mounted GPR can be of great support to perform systematic subsurface surveys for a given landing site as it can provide scientific and operational support in exploring subsurface resources and sample collections which can increase the efficiency of the EVA activities for potential human crews as part of the NASA Constellation Program. In this study we attempt to explore the operational challenges and their impact on the EVA scientific return for operating a rover mounted GPR in support of potential human activity on the moon. In this first field study, we mainly focused on the ability of GPR to support subsurface sample collection and explore shallow subsurface volatiles.

Proliferation attractiveness of nuclear material in a small modular pressure tube SCWR

Energy Technology Data Exchange (ETDEWEB)

McDonald, M.; Pencer, J., E-mail: mcdonamh@aecl.ca, E-mail: pencerj@aecl.ca [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

2013-07-01

The SuperSafe© Reactor (SSR), has been recently proposed as a small modular version of the Canadian supercritical water cooled reactor (SCWR). This reactor is a heavy water moderated, pressure tube reactor using supercritical light water as coolant. The current SSR design is to generate 300 MWe taking advantage of the expected high thermal efficiency (assumed 45%). As one of the reactor types being considered by the Generation-IV International Forum, it is expected that this SCWR design will feature enhanced proliferation resistance over current generation technologies. Proliferation resistance assessments are wide-ranging, multidisciplinary efforts that are typically performed at a number of levels, from a state level down to a specific facility level. One small, but particularly important, sub-assessment is that of nuclear material attractiveness, that is, assessing the quality of nuclear materials throughout the fuel cycle for use in making a nuclear explosive device. The attractiveness of materials for three different SSR fuel options is examined in this work. (author)

Reactor pressure vessel behaviour with a small crack in the cladding

International Nuclear Information System (INIS)

Fayolle, P.; Churier-Bossennec, H.; Faidy, C.

1990-01-01

This paper reports on fracture mechanic analysis of a PWR reactor pressure vessel with a 3.5 mm embedded circumferential crack in the cladding under a small lost of cooling accident transient. Different RTNDT level and effect of irradiation on material properties are considered. The study compares simplified one-dimensional and two-dimensional elastic approach and complete elastoplastic approach using J-parameter. The results show: good correlation between the different elastic approaches, important conservatism of the elastic approach compared to elastoplastic approach, no influence of irradiated material properties. The behavior of a vessel with this type of crack is acceptable for RTNDT less than 135 deg and safety injection temperature of 60 deg

VNIR Multispectral Observations of Rocks at Spirit of St. Louis Crater and Marathon Valley on Th Rim of Endeavour Crater Made by the Opportunity Rover Pancam

Science.gov (United States)

Farrand, W. H.; Johnson, J. R.; Bell, J. F., III; Mittlefehldt, D.W.

2016-01-01

The Mars Exploration Rover Opportunity has been exploring the western rim of the 22 km diameter Endeavour crater since August, 2011. Recently, Opportunity has reached a break in the Endeavour rim that the rover team has named Mara-thon Valley. This is the site where orbital observations from the MRO CRISM imaging spectrometer indicated the presence of iron smectites. On the outer western portion of Marathon Valley, Opportunity explored the crater-form feature dubbed Spirit of St. Louis (SoSL) crater. This presentation describes the 430 to 1009 nm (VNIR) reflectance, measured by the rover's Pancam, of rock units present both at Spirit of St. Louis and within Marathon Valley.

The Mars Hand Lens Imager (MAHLI) aboard the Mars rover, Curiosity

Science.gov (United States)

Edgett, K. S.; Ravine, M. A.; Caplinger, M. A.; Ghaemi, F. T.; Schaffner, J. A.; Malin, M. C.; Baker, J. M.; Dibiase, D. R.; Laramee, J.; Maki, J. N.; Willson, R. G.; Bell, J. F., III; Cameron, J. F.; Dietrich, W. E.; Edwards, L. J.; Hallet, B.; Herkenhoff, K. E.; Heydari, E.; Kah, L. C.; Lemmon, M. T.; Minitti, M. E.; Olson, T. S.; Parker, T. J.; Rowland, S. K.; Schieber, J.; Sullivan, R. J.; Sumner, D. Y.; Thomas, P. C.; Yingst, R. A.

2009-08-01

The Mars Science Laboratory (MSL) rover, Curiosity, is expected to land on Mars in 2012. The Mars Hand Lens Imager (MAHLI) will be used to document martian rocks and regolith with a 2-megapixel RGB color CCD camera with a focusable macro lens mounted on an instrument-bearing turret on the end of Curiosity's robotic arm. The flight MAHLI can focus on targets at working distances of 20.4 mm to infinity. At 20.4 mm, images have a pixel scale of 13.9 μm/pixel. The pixel scale at 66 mm working distance is about the same (31 μm/pixel) as that of the Mars Exploration Rover (MER) Microscopic Imager (MI). MAHLI camera head placement is dependent on the capabilities of the MSL robotic arm, the design for which presently has a placement uncertainty of ~20 mm in 3 dimensions; hence, acquisition of images at the minimum working distance may be challenging. The MAHLI consists of 3 parts: a camera head, a Digital Electronics Assembly (DEA), and a calibration target. The camera head and DEA are connected by a JPL-provided cable which transmits data, commands, and power. JPL is also providing a contact sensor. The camera head will be mounted on the rover's robotic arm turret, the DEA will be inside the rover body, and the calibration target will be mounted on the robotic arm azimuth motor housing. Camera Head. MAHLI uses a Kodak KAI-2020CM interline transfer CCD (1600 x 1200 active 7.4 μm square pixels with RGB filtered microlenses arranged in a Bayer pattern). The optics consist of a group of 6 fixed lens elements, a movable group of 3 elements, and a fixed sapphire window front element. Undesired near-infrared radiation is blocked using a coating deposited on the inside surface of the sapphire window. The lens is protected by a dust cover with a Lexan window through which imaging can be ac-complished if necessary, and targets can be illuminated by sunlight or two banks of two white light LEDs. Two 365 nm UV LEDs are included to search for fluores-cent materials at night. DEA

Flow condensation pressure drop characteristics of R410A-oil mixture inside small diameter horizontal microfin tubes

Energy Technology Data Exchange (ETDEWEB)

Huang, Xiangchao; Ding, Guoliang; Hu, Haitao; Zhu, Yu [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); Gao, Yifeng [International Copper Association Shanghai Office, Shanghai 200020 (China); Deng, Bin [Institute of Heat Transfer Technology, Golden Dragon Precise Copper Tube Group Inc., Shanghai 200135 (China)

2010-11-15

Flow condensation pressure drop characteristics of R410A-oil mixture inside small diameter (5.0 mm and 4.0 mm O.D.) horizontal microfin tubes were investigated experimentally covering nominal oil concentrations from 0% to 5%. The research results indicate that, comparing with the frictional pressure drop of pure R410A, the frictional pressure drop of R410A-oil mixture may decrease by maximum of 18% when the vapor quality is lower than 0.6, and increase by maximum of 13% when the vapor quality is higher than 0.6. A new frictional pressure drop correlation for R410A-oil mixture flow condensation inside microfin tubes is developed based on the refrigerant-oil mixture properties, and can agree with 94% of the experimental data within a deviation of -30% to +30%. (author)

An Overview of a Regenerative Fuel Cell Concept for a Mars Surface Mobile Element (Mars Rover)

Science.gov (United States)

Andersson, T.

2018-04-01

This paper outlines an overview of a regenerative fuel cell concept for a Mars rover. The objectives of the system are to provide electrical and thermal power during the Mars night and to provide electrical power for the operational cycles.

Rescuing Rover: A First Aid and Disaster Guide for Dog Owners

OpenAIRE

Heath, Sebastian E.

1998-01-01

Whether you're hiking with your canine friend in a remote area or work with a dog on a search-and-rescue team or police force, you need to be prepared for emergencies when veterinary service is not available. Rescuing Rover: A First Aid and Disaster Guide for Dog Owners provides dog owners, handlers, and emergency physicians with an understandable guide for safe treatment until the dog can be transported to a veterinarian. Although a number of books describe some techniques for the emergency ...

Broadband Ground Penetrating Radar with conformal antennas for subsurface imaging from a rover

Science.gov (United States)

Stillman, D. E.; Oden, C. P.; Grimm, R. E.; Ragusa, M.

2015-12-01

Ground-Penetrating Radar (GPR) allows subsurface imaging to provide geologic context and will be flown on the next two martian rovers (WISDOM on ExoMars and RIMFAX on Mars 2020). The motivation of our research is to minimize the engineering challenges of mounting a GPR antenna to a spacecraft, while maximizing the scientific capabilities of the GPR. The scientific capabilities increase with the bandwidth as it controls the resolution. Furthermore, ultra-wide bandwidth surveys allow certain mineralogies and rock units to be discriminated based on their frequency-dependent EM or scattering properties. We have designed and field-tested a prototype GPR that utilizes bi-static circularly polarized spiral antennas. Each antenna has a physical size of 61 x 61 x 4 cm, therefore two antennas could be mounted to the underbelly of a MSL-class rover. Spiral antennas were chosen because they have an inherent broadband response and provide a better low frequency response compared with similarly sized linearly polarized antennas. A horizontal spiral radiator emits energy both upward and downward directions. After the radiator is mounted to a metal surface (i.e. the underside of a rover), a cavity is formed that causes the upward traveling energy to reverberate and cause unwanted interference. This interference is minimized by 1) using a high metallization ratio on the spiral to reduce cavity emissions, and 2) placing absorbing material inside the cavity. The resulting antennas provide high gain (0 to 8 dBi) from 200 to 1000 MHz. The low frequency response can be improved by increasing the antenna thickness (i.e., cavity depth). In an initial field test, the antennas were combined with impulse GPR electronics that had ~140 dB of dynamic range (not including antennas) and a sand/clay interface 7 feet deep was detected. To utilize the full bandwidth the antennas, a gated Frequency Modulated Continuous Waveform system will be developed - similar to RIMFAX. The goal is to reach a

Impact of alternative fuel rheology on spraying process of small pressure-swirl atomizer

Energy Technology Data Exchange (ETDEWEB)

Malý, Milan, E-mail: milan.maly@vutbr.cz; Janáčková, Lada; Jedelský, Jan, E-mail: jedelsky@vutbr.cz; Jícha, Miroslav [Brno University of Technology, Faculty of Mechanical Engineering, Energy Institute, Technická 2896/2, 61669 Brno (Czech Republic)

2016-06-30

A systematic investigation was made to analyse the atomizing performance of a small pressure-swirl atomizer with different crude-oil based fuels and water. The atomizer performance is characterized in terms of discharge coefficient, droplet Sauter mean diameter and nozzle efficiency. Phase-Doppler anemometry was used to measure droplets sizes and velocities and to determine the mean structure of the developed spray. A strong dependence of liquid viscosity on the mass flow rate through the atomizer as well as on the spray quality was found and discussed in comparison with relevant literature.

Impact of alternative fuel rheology on spraying process of small pressure-swirl atomizer

Science.gov (United States)

Malý, Milan; Janáčková, Lada; Jedelský, Jan; Jícha, Miroslav

2016-06-01

A systematic investigation was made to analyse the atomizing performance of a small pressure-swirl atomizer with different crude-oil based fuels and water. The atomizer performance is characterized in terms of discharge coefficient, droplet Sauter mean diameter and nozzle efficiency. Phase-Doppler anemometry was used to measure droplets sizes and velocities and to determine the mean structure of the developed spray. A strong dependence of liquid viscosity on the mass flow rate through the atomizer as well as on the spray quality was found and discussed in comparison with relevant literature.

Impact of alternative fuel rheology on spraying process of small pressure-swirl atomizer

International Nuclear Information System (INIS)

Malý, Milan; Janáčková, Lada; Jedelský, Jan; Jícha, Miroslav

2016-01-01

A systematic investigation was made to analyse the atomizing performance of a small pressure-swirl atomizer with different crude-oil based fuels and water. The atomizer performance is characterized in terms of discharge coefficient, droplet Sauter mean diameter and nozzle efficiency. Phase-Doppler anemometry was used to measure droplets sizes and velocities and to determine the mean structure of the developed spray. A strong dependence of liquid viscosity on the mass flow rate through the atomizer as well as on the spray quality was found and discussed in comparison with relevant literature.

Simulation of small break loss of coolant accident in pressurized water reactor (PWR)

International Nuclear Information System (INIS)

Abass, N. M. N.

2012-02-01

A major safety concern in pressurized-water-reactor (PWR) design is the loss-of-coolant accident (LOCA),in which a break in the primary coolant circuit leads to depressurization, boiling of the coolant, consequent reduced cooling of the reactor core, and , unless remedial measures are taken, overheating of the fuel rods. This concern has led to the development of several simulators for safety analysis. This study demonstrates how the passive and active safety systems in conventional and advanced PWR behave during the small break loss of Coolant Accident (SBLOCA). The consequences of SBOLOCA have been simulated using IAEA Generic pressurized Water Reactor Simulator (GPWRS) and personal Computer Transient analyzer (PCTRAN) . The results were presented and discussed. The study has confirmed the major safety advantage of passive plants versus conventional PWRs is that the passive safety systems provide long-term core cooling and decay heat removal without the need for operator actions and without reliance on active safety-related system. (Author)

Learning from the Mars Rover Mission: Scientific Discovery, Learning and Memory

Science.gov (United States)

Linde, Charlotte

2005-01-01

Purpose: Knowledge management for space exploration is part of a multi-generational effort. Each mission builds on knowledge from prior missions, and learning is the first step in knowledge production. This paper uses the Mars Exploration Rover mission as a site to explore this process. Approach: Observational study and analysis of the work of the MER science and engineering team during rover operations, to investigate how learning occurs, how it is recorded, and how these representations might be made available for subsequent missions. Findings: Learning occurred in many areas: planning science strategy, using instrumen?s within the constraints of the martian environment, the Deep Space Network, and the mission requirements; using software tools effectively; and running two teams on Mars time for three months. This learning is preserved in many ways. Primarily it resides in individual s memories. It is also encoded in stories, procedures, programming sequences, published reports, and lessons learned databases. Research implications: Shows the earliest stages of knowledge creation in a scientific mission, and demonstrates that knowledge management must begin with an understanding of knowledge creation. Practical implications: Shows that studying learning and knowledge creation suggests proactive ways to capture and use knowledge across multiple missions and generations. Value: This paper provides a unique analysis of the learning process of a scientific space mission, relevant for knowledge management researchers and designers, as well as demonstrating in detail how new learning occurs in a learning organization.

Small-Scale Metal Tanks for High Pressure Storage of Fluids

Science.gov (United States)

London, Adam (Inventor)

2016-01-01

Small scale metal tanks for high-pressure storage of fluids having tank factors of more than 5000 meters and volumes of ten cubic inches or less featuring arrays of interconnected internal chambers having at least inner walls thinner than gage limitations allow. The chambers may be arranged as multiple internal independent vessels. Walls of chambers that are also portions of external tank walls may be arcuate on the internal and/or external surfaces, including domed. The tanks may be shaped adaptively and/or conformally to an application, including, for example, having one or more flat outer walls and/or having an annular shape. The tanks may have dual-purpose inlet/outlet conduits of may have separate inlet and outlet conduits. The tanks are made by fusion bonding etched metal foil layers patterned from slices of a CAD model of the tank. The fusion bonded foil stack may be further machined.

78 FR 16040 - Petition for Exemption From the Vehicle Theft Prevention Standard; Jaguar Land Rover North...

Science.gov (United States)

2013-03-13

... From the Vehicle Theft Prevention Standard; Jaguar Land Rover North America Llc AGENCY: National... in reducing and deterring motor vehicle theft as compliance with the parts-marking requirements of... Part 543, Exemption from Vehicle Theft Prevention Standard, based on the installation of an antitheft...

Quantitative analysis of digital outcrop data obtained from stereo-imagery using an emulator for the PanCam camera system for the ExoMars 2020 rover

Science.gov (United States)

Barnes, Robert; Gupta, Sanjeev; Gunn, Matt; Paar, Gerhard; Balme, Matt; Huber, Ben; Bauer, Arnold; Furya, Komyo; Caballo-Perucha, Maria del Pilar; Traxler, Chris; Hesina, Gerd; Ortner, Thomas; Banham, Steven; Harris, Jennifer; Muller, Jan-Peter; Tao, Yu

2017-04-01

A key focus of planetary rover missions is to use panoramic camera systems to image outcrops along rover traverses, in order to characterise their geology in search of ancient life. This data can be processed to create 3D point clouds of rock outcrops to be quantitatively analysed. The Mars Utah Rover Field Investigation (MURFI 2016) is a Mars Rover field analogue mission run by the UK Space Agency (UKSA) in collaboration with the Canadian Space Agency (CSA). It took place between 22nd October and 13th November 2016 and consisted of a science team based in Harwell, UK, and a field team including an instrumented Rover platform at the field site near Hanksville (Utah, USA). The Aberystwyth University PanCam Emulator 3 (AUPE3) camera system was used to collect stereo panoramas of the terrain the rover encountered during the field trials. Stereo-imagery processed in PRoViP is rendered as Ordered Point Clouds (OPCs) in PRo3D, enabling the user to zoom, rotate and translate the 3D outcrop model. Interpretations can be digitised directly onto the 3D surface, and simple measurements can be taken of the dimensions of the outcrop and sedimentary features, including grain size. Dip and strike of bedding planes, stratigraphic and sedimentological boundaries and fractures is calculated within PRo3D from mapped bedding contacts and fracture traces. Merging of rover-derived imagery with UAV and orbital datasets, to build semi-regional multi-resolution 3D models of the area of operations for immersive analysis and contextual understanding. In-simulation, AUPE3 was mounted onto the rover mast, collecting 16 stereo panoramas over 9 'sols'. 5 out-of-simulation datasets were collected in the Hanksville-Burpee Quarry. Stereo panoramas were processed using an automated pipeline and data transfer through an ftp server. PRo3D has been used for visualisation and analysis of this stereo data. Features of interest in the area could be annotated, and their distances between to the rover

In Situ Visible to Short Wavelength Imaging Spectroscopy with the Ultra Compact Imaging Spectrometer (UCIS): Case Studies from the Mars Exploration Rovers

Science.gov (United States)

Blaney, D.; Mouroulis, P.; Green, R.; Rodriguez, J.; Sellar, G.; Van Gorp, B.; Wilson, D.

2011-01-01

In Situ imaging spectroscopy provides a way to address complex questions of geological evolution for both aqueous and igneous processes by mapping mineral composition at the spatial scale of rocks and outcrops. Examination of locations studied by the Mars Exploration Rovers Spirit and Opportunity can provide examples of the potential utility and define the needed measurement requirements. A compact instrument is needed to be able to adequately address these science questions from a rover platform. The Ultra Compact Imaging Spectrometer (UCIS) is an instrument designed to address the science need and implementation constraints.

Effect of pressure anisotropy on the m=1 small wavelength modes in Z-pinches

International Nuclear Information System (INIS)

Faghihi, M.

1987-01-01

A generalization of Freidberg's perpendicular MHD model is used to investigate the effect of pressure anisotropy on the small wavelength internal kink (m=1) mode instability in a Z-Pinch. A normal mode analysis of perturbed motion of an incompressible, collisionless and cylindrical plasma is performed. The stability criterion is (rΣB 2 )' ≤ 0, where Σ = 1 - (P parallel - P perpendicular to )/B 2 . It cannot be fulfilled without violation of the fire hose stability condition Σ ≥ 0. (orig.)

High pressure fiber optic sensor system

Science.gov (United States)

Guida, Renato; Xia, Hua; Lee, Boon K; Dekate, Sachin N

2013-11-26

The present application provides a fiber optic sensor system. The fiber optic sensor system may include a small diameter bellows, a large diameter bellows, and a fiber optic pressure sensor attached to the small diameter bellows. Contraction of the large diameter bellows under an applied pressure may cause the small diameter bellows to expand such that the fiber optic pressure sensor may measure the applied pressure.

xLuna - D emonstrator on ESA Mars Rover

Science.gov (United States)

Braga, P.; Henriques, L.; Carvalho, B.; Chevalley, P.; Zulianello, M.

2008-08-01

There is a significant gap between the services offered by existing space qualified Real-Time Operating Systems (RTOS) and those required by the most demanding future space applications. New requirements for autonomy, terrain mapping and navigation, Simultaneous Location and Mapping (SLAM), improvement of the throughput of science tasks, all demand high level services such as file systems or POSIX compliant interfaces. xLuna is an operating system that aims fulfilling these new requirements. Besides providing the typical services that of an RTOS (tasks and interrupts management, timers, message queues, etc), it also includes most of the features available in modern general-purpose operating systems, such as Linux. This paper describes a case study that proposes to demonstrate the usage of xLuna on board a rover currently in use for the development of algorithms in preparation of a mission to Mars.

Rover's Wheel Churns Up Bright Martian Soil (Vertical)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Spirit acquired this mosaic on the mission's 1,202nd Martian day, or sol (May 21, 2007), while investigating the area east of the elevated plateau known as 'Home Plate' in the 'Columbia Hills.' The mosaic shows an area of disturbed soil, nicknamed 'Gertrude Weise' by scientists, made by Spirit's stuck right front wheel. The trench exposed a patch of nearly pure silica, with the composition of opal. It could have come from either a hot-spring environment or an environment called a fumarole, in which acidic, volcanic steam rises through cracks. Either way, its formation involved water, and on Earth, both of these types of settings teem with microbial life. The image is presented here as a vertical projection, as if looking straight down, and in false color, which brings out subtle color differences.

The evaluation of validity of the RELAP5/Mod3 flow regime map for horizontal small diameter tubes at low pressure

Energy Technology Data Exchange (ETDEWEB)

Agafonova, N. [St. Petersburg State Technical Univ. (Russian Federation); Banati, J. [Lappeenranta Univ. of Technology (Finland)

1997-12-31

RELAP5/MOD3 code was developed for Western type power water reactors with vertical steam generators. Thus, this code should be validated also for WWER design with horizontal steam generators. In application for horizontal steam generators the situation with two-phase flow inside small diameter tubes is possible when the first circuit pressure drops in accident below the pressure level in the boiling water. It is known that computer codes have not always modelled correctly the two-phase flow inside horizontal tubes at low pressures (less than 4-6 MPa). It may be the result of erroneous prediction of the flow regime. Correct prediction of the flow regime is especially important for the fully or partly stratified flow in horizontal tubes. The aim of this study is the attempt of verification of the flow regime map, which is used in the RELAP5/MOD3 computer code for two-phase flow in horizontal small diameter tubes. `Small diameter tube` means according RELAP5/MOD3 that the inner diameter of the tube is less (or equal) than 0.018 m. The inner tube diameter in horizontal steam generators is equal 0.013 m. (orig.). 19 refs.

The evaluation of validity of the RELAP5/Mod3 flow regime map for horizontal small diameter tubes at low pressure

Energy Technology Data Exchange (ETDEWEB)

Agafonova, N [St. Petersburg State Technical Univ. (Russian Federation); Banati, J [Lappeenranta Univ. of Technology (Finland)

1998-12-31

RELAP5/MOD3 code was developed for Western type power water reactors with vertical steam generators. Thus, this code should be validated also for WWER design with horizontal steam generators. In application for horizontal steam generators the situation with two-phase flow inside small diameter tubes is possible when the first circuit pressure drops in accident below the pressure level in the boiling water. It is known that computer codes have not always modelled correctly the two-phase flow inside horizontal tubes at low pressures (less than 4-6 MPa). It may be the result of erroneous prediction of the flow regime. Correct prediction of the flow regime is especially important for the fully or partly stratified flow in horizontal tubes. The aim of this study is the attempt of verification of the flow regime map, which is used in the RELAP5/MOD3 computer code for two-phase flow in horizontal small diameter tubes. `Small diameter tube` means according RELAP5/MOD3 that the inner diameter of the tube is less (or equal) than 0.018 m. The inner tube diameter in horizontal steam generators is equal 0.013 m. (orig.). 19 refs.

PDS4 vs PDS3 - A Comparison of PDS Data for Two Mars Rovers - Existing Mars Curiosity Mission Mass Spectrometer (SAM) PDS3 Data vs Future ExoMars Rover Mass Spectrometer (MOMA) PDS4 Data

Science.gov (United States)

Lyness, E.; Franz, H. B.; Prats, B.

2017-12-01

The Sample Analysis at Mars (SAM) instrument is a suite of instruments on Mars aboard the Mars Science Laboratory rover. Centered on a mass spectrometer, SAM delivers its data to the PDS Atmosphere's node in PDS3 format. Over five years on Mars the process of operating SAM has evolved and extended significantly from the plan in place at the time the PDS3 delivery specification was written. For instance, SAM commonly receives double or even triple sample aliquots from the rover's drill. SAM also stores samples in spare cups for long periods of time for future analysis. These unanticipated operational changes mean that the PDS data deliveries are absent some valuable metadata without which the data can be confusing. The Mars Organic Molecule Analyzer (MOMA) instrument is another suite of instruments centered on a mass spectrometer bound for Mars. MOMA is part of the European ExoMars rover mission schedule to arrive on Mars in 2021. While SAM and MOMA differ in some important scientific ways - MOMA uses an linear ion trap compared to the SAM quadropole mass spectrometer and MOMA has a laser desorption experiment that SAM lacks - the data content from the PDS point of view is comparable. Both instruments produce data containing mass spectra acquired from solid samples collected on the surface of Mars. The MOMA PDS delivery will make use of PDS4 improvements to provide a metadata context to the data. The MOMA PDS4 specification makes few assumptions of the operational processes. Instead it provides a means for the MOMA operators to provide the important contextual metadata that was unanticipated during specification development. Further, the software tools being developed for instrument operators will provide a means for the operators to add this crucial metadata at the time it is best know - during operations.

Characteristics of two-phase flow pattern transitions and pressure drop of five refrigerants in horizontal circular small tubes

Energy Technology Data Exchange (ETDEWEB)

Pamitran, A.S. [Department of Mechanical Engineering, University of Indonesia, Kampus Baru UI, Depok 16424 (Indonesia); Choi, Kwang-Il [Graduate School, Chonnam National University, San 96-1, Dunduk-Dong, Yeosu, Chonnam 550-749 (Korea); Oh, Jong-Taek [Department of Refrigeration and Air Conditioning Engineering, Chonnam National University, San 96-1, Dunduk-Dong, Yeosu, Chonnam 550-749 (Korea); Hrnjak, Pega [Department of Mechanical Science and Engineering, ACRC, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801 (United States)

2010-05-15

An experimental investigation on the characteristics of two-phase flow pattern transitions and pressure drop of R-22, R-134a, R-410A, R-290 and R-744 in horizontal small stainless steel tubes of 0.5, 1.5 and 3.0 mm inner diameters is presented. Experimental data were obtained over a heat flux range of 5-40 kW/m{sup 2}, mass flux range of 50-600 kg/(m{sup 2} s), saturation temperature range of 0-15 C, and quality up to 1.0. Experimental data were evaluated with Wang et al. and Wojtan et al. [Wang, C.C., Chiang, C.S., Lu, D.C., 1997. Visual observation of two-phase flow pattern of R-22, R-134a, and R-407C in a 6.5-mm smooth tube. Exp. Therm. Fluid Sci. 15, 395-405; Wojtan, L., Ursenbacher, T., Thome, J.R., 2005. Investigation of flow boiling in horizontal tubes: part I - a new diabatic two-phase flow pattern map. Int. J. Heat Mass Transfer 48, 2955-2969.] flow pattern maps. The effects of mass flux, heat flux, saturation temperature and inner tube diameter on the pressure drop of the working refrigerants are reported. The experimental pressure drop was compared with the predictions from some existing correlations. A new two-phase pressure drop model that is based on a superposition model for two-phase flow boiling of refrigerants in small tubes is presented. (author)

Compositional Variations in Sands of the Bagnold Dunes, Gale Crater, Mars, from Visible-Shortwave Infrared Spectroscopy and Comparison to Ground-Truth from the Curiosity Rover

OpenAIRE

Lapotre, M. G. A.; Ehlmann, B. L.; Minson, S. E.; Arvidson, R. E.; Ayoub, F.; Fraeman, A. A.; Ewing, R. C.; Bridges, N. T.

2017-01-01

During its ascent up Mount Sharp, the Mars Science Laboratory Curiosity rover traversed the Bagnold Dune Field. We model sand modal mineralogy and grain size at four locations near the rover traverse, using orbital shortwave infrared single-scattering albedo spectra and a Markov chain Monte Carlo implementation of Hapke's radiative transfer theory to fully constrain uncertainties and permitted solutions. These predictions, evaluated against in situ measurements at one site from the Curiosity ...

Conceptual studies on the integration of a nuclear reactor system to a manned rover for Mars missions. Final Report, Feb. 1989 - Nov. 1990

International Nuclear Information System (INIS)

El-genk, M.S.; Morley, N.J.

1991-07-01

Multiyear civilian manned missions to explore the surface of Mars are thought by NASA to be possible early in the next century. Expeditions to Mars, as well as permanent bases, are envisioned to require enhanced piloted vehicles to conduct science and exploration activities. Piloted rovers, with 30 kWe user net power (for drilling, sampling and sample analysis, onboard computer and computer instrumentation, vehicle thermal management, and astronaut life support systems) in addition to mobility are being considered. The rover design, for this study, included a four car train type vehicle complete with a hybrid solar photovoltaic/regenerative fuel cell auxiliary power system (APS). This system was designed to power the primary control vehicle. The APS supplies life support power for four astronauts and a limited degree of mobility allowing the primary control vehicle to limp back to either a permanent base or an accent vehicle. The results showed that the APS described above, with a mass of 667 kg, was sufficient to provide live support power and a top speed of five km/h for 6 hours per day. It was also seen that the factors that had the largest effect on the APS mass were the life support power, the number of astronauts, and the PV cell efficiency. The topics covered include: (1) power system options; (2) rover layout and design; (3) parametric analysis of total mass and power requirements for a manned Mars rover; (4) radiation shield design; and (5) energy conversion systems

Preliminary analysis in support to the experimental activities on the mixing process in the pressurizer of a small modular reactor integrated primary system

Energy Technology Data Exchange (ETDEWEB)

Nascimento, Samira R.V.; Lira, Carlos A.B.O.; Bezerra, Jair L.; Silva, Mario A.B.; Silva, Willdauany C.F., E-mail: samiraruana@gmail.com [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear; Lapa, Celso M.F., E-mail: lapa@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Lima, Fernando R.A., E-mail: falima@crcn.gov.br [Centro Regional de Ciencias Nucleares (CRCN/CNEN-NE), Recife, PE (Brazil); Otero, Maria E.M.; Hernandez, Carlos R.G., E-mail: mmontesi@instec.cu [Department of Nuclear Engineering, InSTEC/CUBA, Higher Institute of Technology and Applied Science, La Habana (Cuba)

2015-07-01

Nowadays, there is a renewed interest in the development of advanced/innovative small and medium sized modular reactors (SMRs). The SMRs are variants of the Generation IV systems and usually have attractive characteristics of simplicity, enhanced safety and require limited financial resources. The concept of the integrated primary system reactor (IPSR) is characterized by the inclusion of the entire primary system within a single pressure vessel, including the steam generator and pressurizer. The pressurizer is located within the reactor vessel top, this configuration involves changes on the techniques and is necessary investigate the boron mixing. The present work represents a contribution to the design of an experimental facility planned to provide data relevant for the mixing phenomena in the pressurizer of a compact modular reactor. In particular, in order to evaluate the boron concentration in the surge orifices to simulate the in-surge and out-surge in a facility, scaled 1:200, respect to the ¼ of the pressurizer. The facility behavior studied from one inlet and one outlet of the test section with represent one in-surge e one out-surge the pressurizer of a small modular reactor integrated primary system. (author)

Chemical variations in Yellowknife Bay formation sedimentary rocks analyzed by ChemCam on board the Curiosity rover on Mars

Science.gov (United States)

Mangold, Nicolas; Forni, Olivier; Dromart, G.; Stack, K.M.; Wiens, Roger C.; Gasnault, Olivier; Sumner, Dawn Y.; Nachon, Marion; Meslin, Pierre-Yves; Anderson, Ryan B.; Barraclough, Bruce; Bell, J.F.; Berger, G.; Blaney, D.L.; Bridges, J.C.; Calef, F.; Clark, Brian R.; Clegg, Samuel M.; Cousin, Agnes; Edgar, L.; Edgett, Kenneth S.; Ehlmann, B.L.; Fabre, Cecile; Fisk, M.; Grotzinger, John P.; Gupta, S.C.; Herkenhoff, Kenneth E.; Hurowitz, J.A.; Johnson, J. R.; Kah, Linda C.; Lanza, Nina L.; Lasue, Jeremie; Le Mouélic, S.; Lewin, Eric; Malin, Michael; McLennan, Scott M.; Maurice, S.; Melikechi, Noureddine; Mezzacappa, Alissa; Milliken, Ralph E.; Newsome, H.L.; Ollila, A.; Rowland, Scott K.; Sautter, Violaine; Schmidt, M.E.; Schroder, S.; D'Uston, C.; Vaniman, Dave; Williams, R.A.

2015-01-01

The Yellowknife Bay formation represents a ~5 m thick stratigraphic section of lithified fluvial and lacustrine sediments analyzed by the Curiosity rover in Gale crater, Mars. Previous works have mainly focused on the mudstones that were drilled by the rover at two locations. The present study focuses on the sedimentary rocks stratigraphically above the mudstones by studying their chemical variations in parallel with rock textures. Results show that differences in composition correlate with textures and both manifest subtle but significant variations through the stratigraphic column. Though the chemistry of the sediments does not vary much in the lower part of the stratigraphy, the variations in alkali elements indicate variations in the source material and/or physical sorting, as shown by the identification of alkali feldspars. The sandstones contain similar relative proportions of hydrogen to the mudstones below, suggesting the presence of hydrous minerals that may have contributed to their cementation. Slight variations in magnesium correlate with changes in textures suggesting that diagenesis through cementation and dissolution modified the initial rock composition and texture simultaneously. The upper part of the stratigraphy (~1 m thick) displays rocks with different compositions suggesting a strong change in the depositional system. The presence of float rocks with similar compositions found along the rover traverse suggests that some of these outcrops extend further away in the nearby hummocky plains.

Effect of pressure anisotropy on the m=1 small wavelength modes in Z-pinches

Energy Technology Data Exchange (ETDEWEB)

Faghihi, M. (Royal Inst. of Tech., Stockholm, Sweden. Dept. of Plasma Physics and Fusion Research)

1987-05-01

A generalization of Freidberg's perpendicular MHD model is used to investigate the effect of pressure anisotropy on the small wavelength internal kink (m=1) mode instability in a Z-Pinch. A normal mode analysis of perturbed motion of an incompressible, collisionless and cylindrical plasma is performed. The stability criterion is (r{SIGMA}B{sup 2})' {le} 0, where {SIGMA} = 1 - (P{sub parallel} - P{sub perpendicular} {sub to})/B/sup 2/. It cannot be fulfilled without violation of the fire hose stability condition {SIGMA} {ge} 0.

Modeling cavitation in a rapidly changing pressure field - application to a small ultrasonic horn.

Science.gov (United States)

Žnidarčič, Anton; Mettin, Robert; Dular, Matevž

2015-01-01

Ultrasonic horn transducers are frequently used in applications of acoustic cavitation in liquids. It has been observed that if the horn tip is sufficiently small and driven at high amplitude, cavitation is very strong, and the tip can be covered entirely by the gas/vapor phase for longer time intervals. A peculiar dynamics of the attached cavity can emerge with expansion and collapse at a self-generated frequency in the subharmonic range, i.e. below the acoustic driving frequency. The term "acoustic supercavitation" was proposed for this type of cavitation Žnidarčič et al. (2014) [1]. We tested several established hydrodynamic cavitation models on this problem, but none of them was able to correctly predict the flow features. As a specific characteristic of such acoustic cavitation problems lies in the rapidly changing driving pressures, we present an improved approach to cavitation modeling, which does not neglect the second derivatives in the Rayleigh-Plesset equation. Comparison with measurements of acoustic supercavitation at an ultrasonic horn of 20kHz frequency revealed a good agreement in terms of cavity dynamics, cavity volume and emitted pressure pulsations. The newly developed cavitation model is particularly suited for simulation of cavitating flow in highly fluctuating driving pressure fields. Copyright © 2014 Elsevier B.V. All rights reserved.

Rover's Wheel Churns Up Bright Martian Soil (Stereo)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Spirit acquired this mosaic on the mission's 1,202nd Martian day, or sol (May 21, 2007), while investigating the area east of the elevated plateau known as 'Home Plate' in the 'Columbia Hills.' The mosaic shows an area of disturbed soil, nicknamed 'Gertrude Weise' by scientists, made by Spirit's stuck right front wheel. The trench exposed a patch of nearly pure silica, with the composition of opal. It could have come from either a hot-spring environment or an environment called a fumarole, in which acidic, volcanic steam rises through cracks. Either way, its formation involved water, and on Earth, both of these types of settings teem with microbial life. Multiple images taken with Spirit's panoramic camera are combined here into a stereo view that appears three-dimensional when seen through red-blue glasses, with the red lens on the left.

On-line pressurizer surveillance system design to prevent small break LOCA through PORV using micro-computer

International Nuclear Information System (INIS)

Lee, Jong-Ho; Chang, Soon-Heung

1986-01-01

Small break LOCA caused by a stuck-open PORV is one of the important contributors to nuclear power plant risk. This paper deals with the design of a pressurizer surveillance system using micro-computer to prevent the malfunction of system and has assessed the effect of this improvement through Probabilistic Risk Assessment (PRA) method. Micro-computer diagnoses the malfunction of system by a process checking method and performs automatically backup action related to each malfunction. Owing to this improvement, we can correctly diagnose ''Spurious Opening'', ''Fail to Reclose'' and ''Small break LOCA'' which are difficult for operator to diagnose quickly and correctly and reduce the probability of a human error by an automatic backup action. (author)

Integrating the Teaching of Space Science, Planetary Exploration And Robotics In Elementary And Middle School with Mars Rover Models

Science.gov (United States)

Bering, E. A.; Ramsey, J.; Smith, H.; Boyko, B. S.; Peck, S.; Arcenaux, W. H.

2005-05-01

The present aerospace engineering and science workforce is ageing. It is not clear that the US education system will produce enough qualified replacements to meet the need in the near future. Unfortunately, by the time many students get to high school, it is often too late to get them pointed toward an engineering or science career. Since some college programs require 6 units of high school mathematics for admission, students need to begin consciously preparing for a science or engineering curriculum as early as 6th or 7th grade. The challenge for educators is to convince elementary school students that science and engineering are both exciting, relevant and accessible career paths. This paper describes a program designed to help provide some excitement and relevance. It is based on the task of developing a mobile robot or "Rover" to explore the surface of Mars. There are two components to the program, a curriculum unit and a contest. The curriculum unit is structured as a 6-week planetary science unit for elementary school (grades 3-5). It can also be used as a curriculum unit, enrichment program or extracurricular activity in grades 6-8 by increasing the expected level of scientific sophistication in the mission design. The second component is a citywide competition to select the most outstanding models that is held annually at a local college or University. Primary (Grades 3-5) and middle school (Grades 6-8) students interested in science and engineering will design and build of a model of a Mars Rover to carry out a specific science mission on the surface of Mars. The students will build the models as part of a 6-week Fall semester classroom-learning or homework project on Mars. The students will be given design criteria for a rover, and be required to do basic research on Mars that will determine the operational objectives and structural features of their rover. This module may be used as part of a class studying general science, earth science, solar system

Rover's Wheel Churns Up Bright Martian Soil (False Color)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Spirit acquired this mosaic on the mission's 1,202nd Martian day, or sol (May 21, 2007), while investigating the area east of the elevated plateau known as 'Home Plate' in the 'Columbia Hills.' The mosaic shows an area of disturbed soil, nicknamed 'Gertrude Weise' by scientists, made by Spirit's stuck right front wheel. The trench exposed a patch of nearly pure silica, with the composition of opal. It could have come from either a hot-spring environment or an environment called a fumarole, in which acidic, volcanic steam rises through cracks. Either way, its formation involved water, and on Earth, both of these types of settings teem with microbial life. The image is presented here in false color that is used to bring out subtle differences in color.

A comparison of energy conversion systems for meeting the power requirements of manned rover for Mars missions

International Nuclear Information System (INIS)

El-Genk, M.S.; Morley, N.; Cataldo, R.; Bloomfield, H.

1990-01-01

Minimizing system mass for interplanetary missions is of utmost importance in order to keep launch cost within reasonable bounds. For a manned Mars rover, powered by a nuclear reactor power system, the choice of the energy conversion system can play a significant role in lowering the overall system mass. Not only is the mass of the conversion unit affected by the choice, but also the masses of the reactor core, waste heat rejection system, and the radiation shield which are strongly influenced by the system conversion efficiency and operating condition. Several types of conversion systems are of interest for a nuclear reactor Mars manned application. These conversion systems include: free piston Stirling engines, He/XE closed Brayton cycle (CBC), CO 2 open Brayton, and SiGe/GaP thermoelectric. Optimization studies are conducted to determine the impact of the conversion system on the overall mass of the nuclear power system as well as the mobility power requirement of the Rover vehicle

The new Athena alpha particle X-ray spectrometer for the Mars Exploration Rovers

Science.gov (United States)

Rieder, R.; Gellert, R.; Brückner, J.; Klingelhöfer, G.; Dreibus, G.; Yen, A.; Squyres, S. W.

2003-11-01

The new alpha particle X-ray spectrometer (APXS) is part of the Athena payload of the two Mars Exploration Rovers (MER). The APXS sensor head is attached to the turret of the instrument deployment device (IDD) of the rover. The APXS is a very light-weight instrument for determining the major and minor elemental composition of Martian soils, rocks, and other geological materials at the MER landing sites. The sensor head has simply to be docked by the IDD on the surface of the selected sample. X-ray radiation, excited by alpha particles and X rays of the radioactive sources, is recorded by a high-resolution X-ray detector. The X-ray spectra show elements starting from sodium up to yttrium, depending on their concentrations. The backscattered alpha spectra, measured by a ring of detectors, provide additional data on carbon and oxygen. By means of a proper calibration, the elemental concentrations are derived. Together with data from the two other Athena instruments mounted on the IDD, the samples under investigation can be fully characterized. Key APXS objectives are the determination of the chemistry of crustal rocks and soils and the examination of water-related deposits, sediments, or evaporates. Using the rock abrasion tool attached to the IDD, issues of weathering can be addressed by measuring natural and abraded surfaces of rocks.

Reflectance conversion methods for the VIS/NIR imaging spectrometer aboard the Chang'E-3 lunar rover: based on ground validation experiment data

International Nuclear Information System (INIS)

Liu Bin; Liu Jian-Zhong; Zhang Guang-Liang; Zou Yong-Liao; Ling Zong-Cheng; Zhang Jiang; He Zhi-Ping; Yang Ben-Yong

2013-01-01

The second phase of the Chang'E Program (also named Chang'E-3) has the goal to land and perform in-situ detection on the lunar surface. A VIS/NIR imaging spectrometer (VNIS) will be carried on the Chang'E-3 lunar rover to detect the distribution of lunar minerals and resources. VNIS is the first mission in history to perform in-situ spectral measurement on the surface of the Moon, the reflectance data of which are fundamental for interpretation of lunar composition, whose quality would greatly affect the accuracy of lunar element and mineral determination. Until now, in-situ detection by imaging spectrometers was only performed by rovers on Mars. We firstly review reflectance conversion methods for rovers on Mars (Viking landers, Pathfinder and Mars Exploration rovers, etc). Secondly, we discuss whether these conversion methods used on Mars can be applied to lunar in-situ detection. We also applied data from a laboratory bidirectional reflectance distribution function (BRDF) using simulated lunar soil to test the availability of this method. Finally, we modify reflectance conversion methods used on Mars by considering differences between environments on the Moon and Mars and apply the methods to experimental data obtained from the ground validation of VNIS. These results were obtained by comparing reflectance data from the VNIS measured in the laboratory with those from a standard spectrometer obtained at the same time and under the same observing conditions. The shape and amplitude of the spectrum fits well, and the spectral uncertainty parameters for most samples are within 8%, except for the ilmenite sample which has a low albedo. In conclusion, our reflectance conversion method is suitable for lunar in-situ detection.

Analysis of a small break loss-of-coolant accident of pressurized water reactor by APROS

Energy Technology Data Exchange (ETDEWEB)

Al-Falahi, A. [Helsinki Univ. of Technology, Espoo (Finland); Haennine, M. [VTT Energy, Espoo (Finland); Porkholm, K. [IVO International, Ltd., Vantaa (Finland)

1995-09-01

The purpose of this paper is to study the capability of APROS (Advanced PROcess Simulator) code to simulate the real plant thermal-hydraulic transient of a Small Break Loss-Of-Coolant Accident (SBLOCA) of Loss-Of-Fluid Test (LOFT) facility. The LOFT is a scaled model of a Pressurized Water Reactor (PWR). This work is a part of a larger validation of the APROS thermal-hydraulic models. The results of SBLOCA transient calculated by APROS showed a reasonable agreement with the measured data.

Ground Truthing Orbital Clay Mineral Observations with the APXS Onboard Mars Exploration Rover Opportunity

Science.gov (United States)

Schroeder, C.; Gellert, R.; VanBommel, S.; Clark, B. C.; Ming, D. W.; Mittlefehldt, D. S.; Yen, A. S.

2016-01-01

NASA's Mars Exploration Rover Opportunity has been exploring approximately 22 km diameter Endeavour crater since 2011. Its rim segments predate the Hesperian-age Burns formation and expose Noachian-age material, which is associated with orbital Fe3+-Mg-rich clay mineral observations [1,2]. Moving to an orders of magnitude smaller instrumental field of view on the ground, the clay minerals were challenging to pinpoint on the basis of geochemical data because they appear to be the result of near-isochemical weathering of the local bedrock [3,4]. However, the APXS revealed a more complex mineral story as fracture fills and so-called red zones appear to contain more Al-rich clay minerals [5,6], which had not been observed from orbit. These observations are important to constrain clay mineral formation processes. More detail will be added as Opportunity is heading into her 10th extended mission, during which she will investigate Noachian bedrock that predates Endeavour crater, study sedimentary rocks inside Endeavour crater, and explore a fluid-carved gully. ESA's ExoMars rover will land on Noachian-age Oxia Planum where abundant Fe3+-Mg-rich clay minerals have been observed from orbit, but the story will undoubtedly become more complex once seen from the ground.

The Development of the Chemin Mineralogy Instrument and Its Deployment on Mars (and Latest Results from the Mars Science Laboratory Rover Curiosity)

Science.gov (United States)

Blake, David F.

2014-01-01

The CheMin instrument (short for "Chemistry and Mineralogy") on the Mars Science Laboratory rover Curiosity is one of two "laboratory quality" instruments on board the Curiosity rover that is exploring Gale crater, Mars. CheMin is an X-ray diffractometer that has for the first time returned definitive and fully quantitative mineral identifications of Mars soil and drilled rock. I will describe CheMin's 23-year development from an idea to a spacecraft qualified instrument, and report on some of the discoveries that Curiosity has made since its entry, descent and landing on Aug. 6, 2012, including the discovery and characterization of the first habitable environment on Mars.

Effect of high hydrostatic pressure on small oxygen-related clusters in silicon: LVM studies

International Nuclear Information System (INIS)

Murin, L.I.; Lindstroem, J.L.; Misiuk, A.

2003-01-01

Local vibrational mode (LVM) spectroscopy is used to explore the effect of high hydrostatic pressure (HP) on the formation of small oxygen-related clusters (dimers, trimers, thermal donors, and C-O complexes) at 450 deg. C and 650 deg. C in Cz-Si crystals with different impurity content and prehistory. It is found, in agreement with previous studies, that HP enhances the oxygen clustering in Cz-Si at elevated temperatures. The effect of HP is related mainly to enhancement in the diffusivity of single oxygen atoms and small oxygen aggregates. HP does not noticeably increase the binding energies of the most simple oxygen related complexes like O 2i , C s O ni . The biggest HP effect on the thermal double donor (TDDs) generation is revealed in hydrogenated samples. Heat-treatment of such samples at 450 deg. C under HP results in extremely high TDD introduction rates as well as in a strong increase in the concentration of the first TDD species

Swarmie User Manual: A Rover Used for Multi-agent Swarm Research

Science.gov (United States)

Montague, Gilbert

2014-01-01

The ability to create multiple functional yet cost effective robots is crucial for conducting swarming robotics research. The Center Innovation Fund (CIF) swarming robotics project is a collaboration among the KSC Granular Mechanics and Regolith Operations (GMRO) group, the University of New Mexico Biological Computation Lab, and the NASA Ames Intelligent Robotics Group (IRG) that uses rovers, dubbed "Swarmies", as test platforms for genetic search algorithms. This fall, I assisted in the development of the software modules used on the Swarmies and created this guide to provide thorough instructions on how to configure your workspace to operate a Swarmie both in simulation and out in the field.

Plans for Selection and In-Situ Investigation of Return Samples by the Supercam Instrument Onboard the Mars 2020 Rover

Science.gov (United States)

Wiens, R. C.; Maurice, S.; Mangold, N.; Anderson, R.; Beyssac, O.; Bonal, L.; Clegg, S.; Cousin, A.; DeFlores, L.; Dromart, G.; Fisher, W.; Forni, O.; Fouchet, T.; Gasnault, O.; Grotzinger, J.; Johnson, J.; Martinez-Frias, J.; McLennan, S.; Meslin, P.-Y.; Montmessin, F.; Poulet, F.; Rull, F.; Sharma, S.

2018-04-01

The SuperCam instrument onboard Rover 2020 still provides a complementary set of analyses with IR reflectance and Raman spectroscopy for mineralogy, LIBS for chemistry, and a color imager in order to investigate in-situ samples to return.

Integrated Results from Analysis of the Rocknest Aeolian Deposit by the Curiosity Rover

Science.gov (United States)

Leshin, L. A.; Grotzinger, J. P.; Blake, D. F.; Edgett, K. S.; Gellert, R.; Mahaffy, P. R.; Malin, M. C.; Wiens, R. C.; Treiman, A. H.; Ming, D. W.;

AIAA Educator Academy - Mars Rover Curriculum: A 6 week multidisciplinary space science based curriculum

Science.gov (United States)

Henriquez, E.; Bering, E. A.; Slagle, E.; Nieser, K.; Carlson, C.; Kapral, A.

2013-12-01

The Curiosity mission has captured the imagination of children, as NASA missions have done for decades. The AIAA and the University of Houston have developed a flexible curriculum program that offers children in-depth science and language arts learning culminating in the design and construction of their own model rover. The program is called the Mars Rover Model Celebration. It focuses on students, teachers and parents in grades 3-8. Students learn to research Mars in order to pick a science question about Mars that is of interest to them. They learn principles of spacecraft design in order to build a model of a Mars rover to carry out their mission on the surface of Mars. The model is a mock-up, constructed at a minimal cost from art supplies. This project may be used either informally as an after school club or youth group activity or formally as part of a class studying general science, earth science, solar system astronomy or robotics, or as a multi-disciplinary unit for a gifted and talented program. The project's unique strength lies in engaging students in the process of spacecraft design and interesting them in aerospace engineering careers. The project is aimed at elementary and secondary education. Not only will these students learn about scientific fields relevant to the mission (space science, physics, geology, robotics, and more), they will gain an appreciation for how this knowledge is used to tackle complex problems. The low cost of the event makes it an ideal enrichment vehicle for low income schools. It provides activities that provide professional development to educators, curricular support resources using NASA Science Mission Directorate (SMD) content, and provides family opportunities for involvement in K-12 student learning. This paper will describe the structure and organization of the 6 week curriculum. A set of 30 new 5E lesson plans have been written to support this project as a classroom activity. The challenge of developing interactive

The Mars 2020 Rover Mission: EISD Participation in Mission Science and Exploration

Science.gov (United States)

Fries, M.; Bhartia, R.; Beegle, L.; Burton, A. S.; Ross, A.

2014-01-01

The Mars 2020 Rover mission will search for potential biosignatures on the martian surface, use new techniques to search for and identify tracelevel organics, and prepare a cache of samples for potential return to Earth. Identifying trace organic compounds is an important tenet of searching for potential biosignatures. Previous landed missions have experienced difficulty identifying unambiguously martian, unaltered organic compounds, possibly because any organic species have been destroyed on heating in the presence of martian perchlorates and/or other oxidants. The SHERLOC instrument on Mars 2020 will use ultraviolet (UV) fluorescence and Raman spectroscopy to identify trace organic compounds without heating the samples.

Assessment of Mars Exploration Rover Landing Site Predictions

Science.gov (United States)

Golombek, M. P.

2005-05-01

Comprehensive analyses of remote sensing data during the 3-year effort to select the Mars Exploration Rover landing sites at Gusev crater and Meridiani Planum correctly predicted the safe and trafficable surfaces explored by the two rovers. Gusev crater was predicted to be a relatively low relief surface that was comparably dusty, but less rocky than the Viking landing sites. Available data for Meridiani Planum indicated a very flat plain composed of basaltic sand to granules and hematite that would look completely unlike any of the existing landing sites with a dark, low albedo surface, little dust and very few rocks. Orbital thermal inertia measurements of 315 J m-2 s-0.5 K-1 at Gusev suggested surfaces dominated by duricrust to cemented soil-like materials or cohesionless sand or granules, which is consistent with observed soil characteristics and measured thermal inertias from the surface. THEMIS thermal inertias along the traverse at Gusev vary from 285 at the landing site to 330 around Bonneville rim and show systematic variations that can be related to the observed increase in rock abundance (5-30%). Meridiani has an orbital bulk inertia of ~200, similar to measured surface inertias that correspond to observed surfaces dominated by 0.2 mm sand size particles. Rock abundance derived from orbital thermal differencing techniques suggested that Meridiani Planum would have very low rock abundance, consistent with the rock free plain traversed by Opportunity. Spirit landed in an 8% orbital rock abundance pixel, consistent with the measured 7% of the surface covered by rocks >0.04 m diameter at the landing site, which is representative of the plains away from craters. The orbital albedo of the Spirit traverse varies from 0.19 to 0.30, consistent with surface measurements in and out of dust devil tracks. Opportunity is the first landing in a low albedo portion of Mars as seen from orbit, which is consistent with the dark, dust-free surface and measured albedos. The

Mars Rover Curriculum: Teacher Self Reporting of Increased Frequency and Confidence in their Science and Language Arts Instruction

Science.gov (United States)

Bering, E. A.; Carlson, C.; Nieser, K.; Slagle, E.

2013-12-01

The University of Houston is in the process of developing a flexible program that offers children an in-depth educational experience culminating in the design and construction of their own model Mars rover. The program is called the Mars Rover Model Celebration (MRC). It focuses on students, teachers and parents in grades 3-8. Students design and build a model of a Mars rover to carry out a student selected science mission on the surface of Mars. A total of 65 Mars Rover teachers from the 2012-2013 cohort were invited to complete the Mars Rover Teacher Evaluation Survey. The survey was administered online and could be taken at the convenience of the participant. In total, 29 teachers participated in the survey. Teachers were asked to rate their current level of confidence in their ability to teach specific topics within the Earth and Life Science realms, as well as their confidence in their ability to implement teaching strategies with their students. In addition, they were asked to rate the degree to which they felt their confidence increased in the past year as a result of their participation in the MRC program. The majority of teachers (81-90%) felt somewhat to very confident in their ability to effectively teach concepts related to earth and life sciences to their students. In addition, many of the teachers felt that their confidence in teaching these concepts increased somewhat to quite a bit as a result of their participation in the MRC program (54-88%). The most striking increase in this area was the reported 48% of teachers who felt their confidence in teaching 'Earth and the solar system and universe' increased 'Quite a bit' as a result of their participation in the MRC program. The vast majority of teachers (86-100%) felt somewhat to very confident in their ability to effectively implement all of the listed teaching strategies. In addition, the vast majority reported believing that their confidence increased somewhat to quite a bit as a result of their

The Mars Science Laboratory Curiosity rover Mastcam instruments: Preflight and in-flight calibration, validation, and data archiving

Science.gov (United States)

Bell, J. F.; Godber, A.; McNair, S.; Caplinger, M. A.; Maki, J. N.; Lemmon, M. T.; Van Beek, J.; Malin, M. C.; Wellington, D.; Kinch, K. M.; Madsen, M. B.; Hardgrove, C.; Ravine, M. A.; Jensen, E.; Harker, D.; Anderson, R. B.; Herkenhoff, K. E.; Morris, R. V.; Cisneros, E.; Deen, R. G.

2017-07-01

The NASA Curiosity rover Mast Camera (Mastcam) system is a pair of fixed-focal length, multispectral, color CCD imagers mounted 2 m above the surface on the rover's remote sensing mast, along with associated electronics and an onboard calibration target. The left Mastcam (M-34) has a 34 mm focal length, an instantaneous field of view (IFOV) of 0.22 mrad, and a FOV of 20° × 15° over the full 1648 × 1200 pixel span of its Kodak KAI-2020 CCD. The right Mastcam (M-100) has a 100 mm focal length, an IFOV of 0.074 mrad, and a FOV of 6.8° × 5.1° using the same detector. The cameras are separated by 24.2 cm on the mast, allowing stereo images to be obtained at the resolution of the M-34 camera. Each camera has an eight-position filter wheel, enabling it to take Bayer pattern red, green, and blue (RGB) "true color" images, multispectral images in nine additional bands spanning 400-1100 nm, and images of the Sun in two colors through neutral density-coated filters. An associated Digital Electronics Assembly provides command and data interfaces to the rover, 8 Gb of image storage per camera, 11 bit to 8 bit companding, JPEG compression, and acquisition of high-definition video. Here we describe the preflight and in-flight calibration of Mastcam images, the ways that they are being archived in the NASA Planetary Data System, and the ways that calibration refinements are being developed as the investigation progresses on Mars. We also provide some examples of data sets and analyses that help to validate the accuracy and precision of the calibration.

The Mars Science Laboratory Curiosity rover Mastcam instruments: Preflight and in-flight calibration, validation, and data archiving

Science.gov (United States)

Bell, James F.; Godber, A.; McNair, S.; Caplinger, M.A.; Maki, J.N.; Lemmon, M.T.; Van Beek, J.; Malin, M.C.; Wellington, D.; Kinch, K.M.; Madsen, M.B.; Hardgrove, C.; Ravine, M.A.; Jensen, E.; Harker, D.; Anderson, Ryan; Herkenhoff, Kenneth E.; Morris, R.V.; Cisneros, E.; Deen, R.G.

2017-01-01

The NASA Curiosity rover Mast Camera (Mastcam) system is a pair of fixed-focal length, multispectral, color CCD imagers mounted ~2 m above the surface on the rover's remote sensing mast, along with associated electronics and an onboard calibration target. The left Mastcam (M-34) has a 34 mm focal length, an instantaneous field of view (IFOV) of 0.22 mrad, and a FOV of 20° × 15° over the full 1648 × 1200 pixel span of its Kodak KAI-2020 CCD. The right Mastcam (M-100) has a 100 mm focal length, an IFOV of 0.074 mrad, and a FOV of 6.8° × 5.1° using the same detector. The cameras are separated by 24.2 cm on the mast, allowing stereo images to be obtained at the resolution of the M-34 camera. Each camera has an eight-position filter wheel, enabling it to take Bayer pattern red, green, and blue (RGB) “true color” images, multispectral images in nine additional bands spanning ~400–1100 nm, and images of the Sun in two colors through neutral density-coated filters. An associated Digital Electronics Assembly provides command and data interfaces to the rover, 8 Gb of image storage per camera, 11 bit to 8 bit companding, JPEG compression, and acquisition of high-definition video. Here we describe the preflight and in-flight calibration of Mastcam images, the ways that they are being archived in the NASA Planetary Data System, and the ways that calibration refinements are being developed as the investigation progresses on Mars. We also provide some examples of data sets and analyses that help to validate the accuracy and precision of the calibration

Nomad rover field experiment, Atacama Desert, Chile 1. Science results overview

Science.gov (United States)

Cabrol, N. A.; Thomas, G.; Witzke, B.

2001-04-01

Nomad was deployed for a 45 day traverse in the Atacama Desert, Chile, during the summer of 1997. During this traverse, 1 week was devoted to science experiments. The goal of the science experiments was to test different planetary surface exploration strategies that included (1) a Mars mission simulation, (2) a science on the fly experiment, where the rover was kept moving 75% of the operation time. (The goal of this operation was to determine whether or not successful interpretation of the environment is related to the time spent on a target. The role of mobility in helping the interpretation was also assessed.) (3) a meteorite search using visual and instrumental methods to remotely identify meteorites in extreme environments, and (4) a time-delay experiment with and without using the panospheric camera. The results were as follow: the remote science team positively identified the main characteristics of the test site geological environment. The science on the fly experiment showed that the selection of appropriate targets might be even more critical than the time spent on a study area to reconstruct the history of a site. During the same operation the science team members identified and sampled a rock from a Jurassic outcrop that they proposed to be a fossil. The presence of paleolife indicators in this rock was confirmed later by laboratory analysis. Both visual and instrumental modes demonstrated the feasibility, in at least some conditions, of carrying out a field search for meteorites by using remote-controlled vehicles. Finally, metrics collected from the observation of the science team operations, and the use team members made of mission data, provided critical information on what operation sequences could be automated on board rovers in future planetary surface explorations.

Mars Exploration Rover Pancam Photometric Data QUBs: Definition and Example Uses.

Science.gov (United States)

Soderblom, J. M.; Bell, J. F.; Arvidson, R. E.; Johnson, J. R.; Johnson, M. J.; Seelos, F. P.

2004-12-01

Pancam multi-spectral observations acquired at the Mars Exploration Rover Spirit and Opportunity landing sites are being assembled into a multi-layer format know as a QUB. For any given pixel in a Pancam image the QUB will contain values for the radiance factor, incidence (i), emission (e), and phase (g) angles, X, Y, and Z distance in a rover-based coordinate system, disparity in number of pixels between the left and right eye images and range data. Good range data is required for the generation of a Pancam QUB. The radiance factor (I/F, where I is the measured scene radiance on sensor and π F is the incident solar irradiance) is calculated using a combination of preflight calibration data and information obtained from near-simultaneous observations of an onboard reflectance calibration target. The range, X, Y, Z and disparity data, and i, e, and g are calculated using routines developed by JPL's MIPL and Cornell. When possible, these data have been interpolated to maximize parameter coverage; a map of non-interpolated data is also included in each QUB. QUBs should prove very useful in photometric studies (e.g., Johnson et al.; Seelos, et al., this conference), detailed spectral analyses (e.g., Bell et al., this conference), and detailed topographic/DTM studies. Here we present two examples of the utilization of the information contained in Pancam QUBs. In one example we remove the photometric variability from spectra collected from multiple facets of a rock using knowledge of i, e, g and derived photometric functions. This is necessary if one wishes to conduct comparative studies of observations acquired under varying geometries and lighting conditions. In another example we present an analysis using the discrete ordinate multiple scattering radiative transfer code DISORT where we separate the atmosphere and surface contributions of the surface reflectance.

Mars Exploration Rovers Landing Dispersion Analysis

Science.gov (United States)

Knocke, Philip C.; Wawrzyniak, Geoffrey G.; Kennedy, Brian M.; Desai, Prasun N.; Parker, TImothy J.; Golombek, Matthew P.; Duxbury, Thomas C.; Kass, David M.

2004-01-01

Landing dispersion estimates for the Mars Exploration Rover missions were key elements in the site targeting process and in the evaluation of landing risk. This paper addresses the process and results of the landing dispersion analyses performed for both Spirit and Opportunity. The several contributors to landing dispersions (navigation and atmospheric uncertainties, spacecraft modeling, winds, and margins) are discussed, as are the analysis tools used. JPL's MarsLS program, a MATLAB-based landing dispersion visualization and statistical analysis tool, was used to calculate the probability of landing within hazardous areas. By convolving this with the probability of landing within flight system limits (in-spec landing) for each hazard area, a single overall measure of landing risk was calculated for each landing ellipse. In-spec probability contours were also generated, allowing a more synoptic view of site risks, illustrating the sensitivity to changes in landing location, and quantifying the possible consequences of anomalies such as incomplete maneuvers. Data and products required to support these analyses are described, including the landing footprints calculated by NASA Langley's POST program and JPL's AEPL program, cartographically registered base maps and hazard maps, and flight system estimates of in-spec landing probabilities for each hazard terrain type. Various factors encountered during operations, including evolving navigation estimates and changing atmospheric models, are discussed and final landing points are compared with approach estimates.

Endotracheal tube resistance and inertance in a model of mechanical ventilation of newborns and small infants—the impact of ventilator settings on tracheal pressure swings

International Nuclear Information System (INIS)

Hentschel, Roland; Buntzel, Julia; Guttmann, Josef; Schumann, Stefan

2011-01-01

Resistive properties of endotracheal tubes (ETTs) are particularly relevant in newborns and small infants who are generally ventilated through ETTs with a small inner diameter. The ventilation rate is also high and the inspiratory time (ti) is short. These conditions effectuate high airway flows with excessive flow acceleration, so airway resistance and inertance play an important role. We carried out a model study to investigate the impact of varying ETT size, lung compliance and ventilator settings, such as peak inspiratory pressure (PIP), positive end expiratory pressure (PEEP) and inspiratory time (ti) on the pressure–flow characteristics with respect to the resistive and inertive properties of the ETT. Pressure at the Y piece was compared to direct measurement of intratracheal pressure (P trach ) at the tip of the ETT, and pressure drop (ΔP ETT ) was calculated. Applying published tube coefficients (Rohrer's constants and inertance), P trach was calculated from ventilator readings and compared to measured P trach using the root-mean-square error. The most relevant for ΔP ETT was the ETT size, followed by (in descending order) PIP, compliance, ti and PEEP, with gas flow velocity being the principle in common for all these parameters. Depending on the ventilator settings ΔP ETT exceeded 8 mbar in the smallest 2.0 mm ETT. Consideration of inertance as an additional effect in this setting yielded a better agreement of calculated versus measured P trach than Rohrer's constants alone. We speculate that exact tracheal pressure tracings calculated from ventilator readings by applying Rohrer's equation and the inertance determination to small size ETTs would be helpful. As an integral part of ventilator software this would (1) allow an estimate of work of breathing and implementation of an automatic tube compensation, and (2) be important for gentle ventilation in respiratory care, especially of small infants, since it enables the physician to

Exploration of Mars with the ChemCam LIBS Instrument and the Curiosity Rover

Science.gov (United States)

Newsom, Horton E.

2016-01-01

The Mars Science Laboratory (MSL) Curiosity rover landed on Mars in August 2012, and has been exploring the planet ever since. Dr. Horton E. Newsom will discuss the MSL's design and main goal, which is to characterize past environments that may have been conducive to the evolution and sustainability of life. He will also discuss Curiosity's science payload, and remote sensing, analytical capabilities, and direct discoveries of the Chemistry & Camera (ChemCam) instrument, which is the first Laser Induced Breakdown Spectrometer (LIBS) to operate on another planetary surface and determine the chemistry of the rocks and soils.

Neuroprotective effect of erythropoietin against pressure ulcer in a mouse model of small fiber neuropathy.

Directory of Open Access Journals (Sweden)

Aurore Danigo

Full Text Available An increased risk of skin pressure ulcers (PUs is common in patients with sensory neuropathies, including those caused by diabetes mellitus. Recombinant human erythropoietin (rhEPO has been shown to protect the skin against PUs developed in animal models of long-term diabetes. The aim of this work was to determine whether rhEPO could prevent PU formation in a mouse model of drug-induced SFN. Functional SFN was induced by systemic injection of resiniferatoxin (RTX, 50 µg/kg, i.p.. RhEPO (3000 UI/kg, i.p. was given the day before RTX injection and then every other day. Seven days after RTX administration, PUs were induced by applying two magnetic plates on the dorsal skin. RTX-treated mice expressed thermal and mechanical hypoalgesia and showed calcitonin gene-related peptide (CGRP and substance P (SP depletion without nerve degeneration or vascular dysfunction. RTX mice developed significantly larger stage 2 PUs than Vehicle mice. RhEPO prevented thermal and mechanical hypoalgesia and neuropeptide depletion in small nerve fibers. RhEPO increased hematocrit and altered endothelium-dependent vasodilatation without any effect on PU formation in Vehicle mice. The characteristics of PUs in RTX mice treated with rhEPO and Vehicle mice were found similar. In conclusion, RTX appeared to increased PU development through depletion of CGRP and SP in small nerve fibers, whereas systemic rhEPO treatment had beneficial effect on peptidergic nerve fibers and restored skin protective capacities against ischemic pressure. Our findings support the evaluation of rhEPO and/or its non-hematopoietic analogs in preventing to prevent PUs in patients with SFN.

Extreme Temperature Performance of Automotive-Grade Small Signal Bipolar Junction Transistors

Science.gov (United States)

Boomer, Kristen; Damron, Benny; Gray, Josh; Hammoud, Ahmad

2018-01-01

Electronics designed for space exploration missions must display efficient and reliable operation under extreme temperature conditions. For example, lunar outposts, Mars rovers and landers, James Webb Space Telescope, Europa orbiter, and deep space probes represent examples of missions where extreme temperatures and thermal cycling are encountered. Switching transistors, small signal as well as power level devices, are widely used in electronic controllers, data instrumentation, and power management and distribution systems. Little is known, however, about their performance in extreme temperature environments beyond their specified operating range; in particular under cryogenic conditions. This report summarizes preliminary results obtained on the evaluation of commercial-off-the-shelf (COTS) automotive-grade NPN small signal transistors over a wide temperature range and thermal cycling. The investigations were carried out to establish a baseline on functionality of these transistors and to determine suitability for use outside their recommended temperature limits.

Literature investigation of air/steam ingress through small cracks in concrete wall under pressure differences

International Nuclear Information System (INIS)

Jiang, J.T.

2008-01-01

Traditionally within CANDU safety analysis, a loss coefficient of ∼2.8 is used to characterize turbulent flow leakage through narrow, sharp-edged cracks into, and out of Steam Protected Rooms (SPRs). In the event of main steam line break (MSLB), the pressure differences observed between SPRs and the surrounding area of the powerhouse range from 0.01kPa to 0.1 kPa. The relatively low pressure differences, coupled with narrow crack sizes, for instance, below 1 mm, may result in laminar flow leakage pathways as opposed to the turbulent variety assumed in analysis. The main purpose of this paper is thus (a) to calculate the loss coefficient for laminar flow through small cracks; and (b) to assess the effect of steam ingress to SPRs when the flow through some or all of the room leakage area is assumed to be laminar. Based on the literature review, the loss coefficient for laminar flow, through 1 mm crack size at 0.1 kPa pressure difference, ranges from 10 to about 65. This value represents an increase in loss coefficient of 3 ∼ 22 times the loss coefficient used for SPR safety analysis. The actual volumetric leakage rate is therefore 3 ∼ 8 times smaller than the amount previously applied. This paper demonstrates how the traditional loss coefficient used in safety analysis is extremely conservative in the analysis of the SPRs steam ingress phenomenon. (author)

Literature investigation of air/steam ingress through small cracks in concrete wall under pressure differences

Energy Technology Data Exchange (ETDEWEB)

Jiang, J.T. [McMaster Univ., Engineering Physics Dept., Hamilton, Ontario (Canada)], E-mail: jiangj3@mcmaster.ca

2008-07-01

Traditionally within CANDU safety analysis, a loss coefficient of {approx}2.8 is used to characterize turbulent flow leakage through narrow, sharp-edged cracks into, and out of Steam Protected Rooms (SPRs). In the event of main steam line break (MSLB), the pressure differences observed between SPRs and the surrounding area of the powerhouse range from 0.01kPa to 0.1 kPa. The relatively low pressure differences, coupled with narrow crack sizes, for instance, below 1 mm, may result in laminar flow leakage pathways as opposed to the turbulent variety assumed in analysis. The main purpose of this paper is thus (a) to calculate the loss coefficient for laminar flow through small cracks; and (b) to assess the effect of steam ingress to SPRs when the flow through some or all of the room leakage area is assumed to be laminar. Based on the literature review, the loss coefficient for laminar flow, through 1 mm crack size at 0.1 kPa pressure difference, ranges from 10 to about 65. This value represents an increase in loss coefficient of 3 {approx} 22 times the loss coefficient used for SPR safety analysis. The actual volumetric leakage rate is therefore 3 {approx} 8 times smaller than the amount previously applied. This paper demonstrates how the traditional loss coefficient used in safety analysis is extremely conservative in the analysis of the SPRs steam ingress phenomenon. (author)

An organic cosmo-barometer: Distinct pressure and temperature effects for methyl substituted polycyclic aromatic hydrocarbons

International Nuclear Information System (INIS)

Montgomery, Wren; Watson, Jonathan S.; Sephton, Mark A.

2014-01-01

There are a number of key structures that can be used to reveal the formation and modification history of organic matter in the cosmos. For instance, the susceptibility of organic matter to heat is well documented and the relative thermal stabilities of different isomers can be used as cosmothermometers. Yet despite being an important variable, no previously recognized organic marker of pressure exists. The absence of a pressure marker is unfortunate considering our ability to effectively recognize extraterrestrial organic structures both remotely and in the laboratory. There are a wide variety of pressures in cosmic settings that could potentially be reflected by organic structures. Therefore, to develop an organic cosmic pressure marker, we have used state-of-the-art diamond anvil cell (DAC) and synchrotron-source Fourier transform infrared (FTIR) spectroscopy to reveal the effects of pressure on the substitution patterns for representatives of the commonly encountered methyl substituted naphthalenes, specifically the dimethylnaphthalenes. Interestingly, although temperature and pressure effects are concordant for many isomers, pressure appears to have the opposite effect to heat on the final molecular architecture of the 1,5-dimethylnaphthalene isomer. Our data suggest the possibility of the first pressure parameter or 'cosmo-barometer' (1,5-dimethylnaphthalene/total dimethylnaphthalenes) that can distinguish pressure from thermal effects. Information can be obtained from the new pressure marker either remotely by instrumentation on landers or rovers or directly by laboratory measurement, and its use has relevance for all cases where organic matter, temperature, and pressure interplay in the cosmos.

Processing of Mars Exploration Rover Imagery for Science and Operations Planning

Science.gov (United States)

Alexander, Douglass A.; Deen, Robert G.; Andres, Paul M.; Zamani, Payam; Mortensen, Helen B.; Chen, Amy C.; Cayanan, Michael K.; Hall, Jeffrey R.; Klochko, Vadim S.; Pariser, Oleg;

Mars Rover Sample Return aerocapture configuration design and packaging constraints

Science.gov (United States)

Lawson, Shelby J.

1989-01-01

This paper discusses the aerodynamics requirements, volume and mass constraints that lead to a biconic aeroshell vehicle design that protects the Mars Rover Sample Return (MRSR) mission elements from launch to Mars landing. The aerodynamic requirements for Mars aerocapture and entry and packaging constraints for the MRSR elements result in a symmetric biconic aeroshell that develops a L/D of 1.0 at 27.0 deg angle of attack. A significant problem in the study is obtaining a cg that provides adequate aerodynamic stability and performance within the mission imposed constraints. Packaging methods that relieve the cg problems include forward placement of aeroshell propellant tanks and incorporating aeroshell structure as lander structure. The MRSR missions developed during the pre-phase A study are discussed with dimensional and mass data included. Further study is needed for some missions to minimize MRSR element volume so that launch mass constraints can be met.

Design and operation of the Rover vacuum system

International Nuclear Information System (INIS)

Wagner, E.P. Jr.; Griffith, D.L.; Rivera, J.M.

1997-01-01

The Rover process for recovering unused uranium from graphite fuels was operated during 1983 and 1984, and then shut down in 1984. The first steps of the process used fluidized alumina beds to burn away the graphite and produce a uranium bearing ash. The ash was then transferred to a different process cell for acid dissolution. At the time of shutdown, a significant, but unmeasureable, quantity of highly enriched uranium was left in the process vessels. Normal decontamination procedures could not be used due to plugged process lines and the exclusion of moderator materials (water or finely divided organic substances) for criticality safety. The presence of highly enriched uranium in poorly defined quantity and configuration led to concerns for criticality safety, nuclear materials accountability, and physical security. A project was established to eliminate these concerns by cleaning and/or removing the process vessels, piping, and cells and sending the recovered Uranium Bearing Material (UBM) to secure storage. A key element of this project was the design of a system for collecting and transporting dry solids to a location where they could be loaded into critically favorable storage cans

Intracranial pressure following complete removal of a small demarcated brain tumor

DEFF Research Database (Denmark)

Andresen, Morten; Juhler, Marianne

2014-01-01

OBJECTIVES: Current published normal values for intracranial pressure (ICP) are extrapolated from lumbar CSF pressure measurements and ICP measurements in patients treated for CSF pressure disorders. There is an emerging agreement that true normal ICP values are needed for diagnostic and therapeu...... and the ICP target range in hydrocephalus treatment....

Role of 5-hydroxytryptamine mechanisms in mediating the effects of small intestinal glucose on blood pressure and antropyloroduodenal motility in older subjects

NARCIS (Netherlands)

Gentilcore, Diana; Little, Tanya J.; Feinle-Bisset, Christine; Samsom, Melvin; Smout, André J. P. M.; Horowitz, Michael; Jones, Karen L.

2007-01-01

Postprandial hypotension is an important clinical problem, particularly in the elderly. 5-Hydroxytryptamine3 (5-HT3) mechanisms may be important in the regulation of splanchnic blood flow and blood pressure (BP), and in mediating the effects of small intestinal nutrients on gastrointestinal

Fracture toughness behaviour using small CCT specimen of Zr-2.5Nb pressure tube materials

International Nuclear Information System (INIS)

Oh, Dong Joon; Kim, Young Suk; Ahn, Sang Bok; Im, Kyung Soo; Kwon, Sang Chul; Cheong, Yong Mu

2001-03-01

Fracture toughness of Zr-2.5Nb pressure tube is the essential data to estimate the CCL(critical crack length) for the concept of LBB(Leak-Before-Break) in PHWR. Zr-2.5Nb pressure tubes could be degraded due to the absorption of hydrogen from coolant and the irradiation. To investigate the fracture toughness behaviour such as J-resistance curves, dJ/da, and CCL of some Zr-alloys (CANDU-double, -quad, CW-E125, TMT-E125, E-635), the transverse tensile test and the fracture toughness test of small CCT (Curved Compact Tension) specimen with 17 mm width were carried out with the variation of testing temperature at different testing condition. To define the fracture mechanism of degradation, the fractographic comparison of fracture surface was performed using the stereoscope and SEM. In addition, the effect of non-uniformed pre-fatigue crack was also studied. In conclusion, CANDU double-melted was less tougher than CANDU quad-melted and the hydrogen embrittlement was found at room temperature. Finally, while the effect of non-uniformed pre-fatigue crack was considerable at room temperature, this effect was disappeared at 250-300 .deg. C

Role of 5-hydroxytryptamine mechanisms in mediating the effects of small intestinal glucose on blood pressure and antropyloroduodenal motility in older subjects

NARCIS (Netherlands)

Gentilcore, Diana; Little, Tanya J.; Feinle-Bisset, Christine; Samsom, Melvin; Smout, Andre J. P. M.; Horowitz, Michael; Jones, Karen L.

2007-01-01

5-hydroxytryptamine mechanisms in mediating the effects of small intestinal glucose on blood pressure and antropyloroduodenal motility in older subjects. Am J Physiol Gastrointest Liver Physiol 293: G692-G698, 2007. First published August 9, 2007; doi:10.1152/ajpgi.00199.2007.-Postprandial

A high pressure study of calmodulin-ligand interactions using small-angle X-ray and elastic incoherent neutron scattering.

Science.gov (United States)

Cinar, Süleyman; Al-Ayoubi, Samy; Sternemann, Christian; Peters, Judith; Winter, Roland; Czeslik, Claus

2018-01-31

Calmodulin (CaM) is a Ca 2+ sensor and mediates Ca 2+ signaling through binding of numerous target ligands. The binding of ligands by Ca 2+ -saturated CaM (holo-CaM) is governed by attractive hydrophobic and electrostatic interactions that are weakened under high pressure in aqueous solutions. Moreover, the potential formation of void volumes upon ligand binding creates a further source of pressure sensitivity. Hence, high pressure is a suitable thermodynamic variable to probe protein-ligand interactions. In this study, we compare the binding of two different ligands to holo-CaM as a function of pressure by using X-ray and neutron scattering techniques. The two ligands are the farnesylated hypervariable region (HVR) of the K-Ras4B protein, which is a natural binding partner of holo-CaM, and the antagonist trifluoperazine (TFP), which is known to inhibit holo-CaM activity. From small-angle X-ray scattering experiments performed up to 3000 bar, we observe a pressure-induced partial unfolding of the free holo-CaM in the absence of ligands, where the two lobes of the dumbbell-shaped protein are slightly swelled. In contrast, upon binding TFP, holo-CaM forms a closed globular conformation, which is pressure stable at least up to 3000 bar. The HVR of K-Ras4B shows a different binding behavior, and the data suggest the dissociation of the holo-CaM/HVR complex under high pressure, probably due to a less dense protein contact of the HVR as compared to TFP. The elastic incoherent neutron scattering experiments corroborate these findings. Below 2000 bar, pressure induces enhanced atomic fluctuations in both holo-CaM/ligand complexes, but those of the holo-CaM/HVR complex seem to be larger. Thus, the inhibition of holo-CaM by TFP is supported by a low-volume ligand binding, albeit this is not associated with a rigidification of the complex structure on the sub-ns Å-scale.

A compact led lidar system fitted for a mars rover - design and ground experiment

Science.gov (United States)

Ong, Prane Mariel B.; Shiina, Tatsuo; Manago, Naohiro; Kuze, Hiroaki; Senshu, Hiroki; Otobe, Naohito; Hashimoto, George; Kawabata, Yasuhiro

2018-04-01

A compact LED lidar was constructed and fieldtested with the aim to observe the Mars' dust devils. To be able to fit it on the Mars rover, a specialized Cassegrain telescope was designed to be within a 10 cm-cube, with a field of view of 3mrad. The transmitter has 385 nm LED light source with 3 cmϕ opening, 70mrad divergence, 0.75W (7.5nJ/10ns) pulse power, and 500 kHz repetition frequency. The configuration of the optical system is biaxial to easily configure the overlap between their optical axes.

Determination of respiratory system compliance during pressure support ventilation by small variations of pressure support.

Science.gov (United States)

Becher, Tobias; Schädler, Dirk; Rostalski, Philipp; Zick, Günther; Frerichs, Inéz; Weiler, Norbert

2017-09-22

In mechanically ventilated patients, measurement of respiratory system compliance (C rs ) is of high clinical interest. Spontaneous breathing activity during pressure support ventilation (PSV) can impede the correct assessment of C rs and also alter the true C rs by inducing lung recruitment. We describe a method for determination of C rs during PSV and assess its accuracy in a study on 20 mechanically ventilated patients. To assess C rs during pressure support ventilation (C rs,PSV ), we performed repeated changes in pressure support level by ± 2 cmH 2 O. C rs,PSV was calculated from the volume change induced by these changes in pressure support level, taking into account the inspiration time and the expiratory time constant. As reference methods, we used C rs , measured during volume controlled ventilation (C rs,VCV ). In a post-hoc analysis, we assessed C rs during the last 20% of the volume-controlled inflation (C rs,VCV20 ). Values were compared by linear regression and Bland-Altman methods comparison. Comparing C rs,PSV to the reference value C rs,VCV , we found a coefficient of determination (r 2 ) of 0.90, but a relatively high bias of - 7 ml/cm H 2 O (95% limits of agreement - 16.7 to + 2.7 ml/cmH 2 O). Comparison with C rs,VCV20 resulted in a negligible bias (- 1.3 ml/cmH 2 O, 95% limits of agreement - 13.9 to + 11.3) and r 2 of 0.81. We conclude that the novel method provides an estimate of end-inspiratory C rs during PSV. Despite its limited accuracy, it might be useful for non-invasive monitoring of C rs in patients undergoing pressure support ventilation.

So small, so loud: extremely high sound pressure level from a pygmy aquatic insect (Corixidae, Micronectinae).

Science.gov (United States)

Sueur, Jérôme; Mackie, David; Windmill, James F C

2011-01-01

To communicate at long range, animals have to produce intense but intelligible signals. This task might be difficult to achieve due to mechanical constraints, in particular relating to body size. Whilst the acoustic behaviour of large marine and terrestrial animals has been thoroughly studied, very little is known about the sound produced by small arthropods living in freshwater habitats. Here we analyse for the first time the calling song produced by the male of a small insect, the water boatman Micronecta scholtzi. The song is made of three distinct parts differing in their temporal and amplitude parameters, but not in their frequency content. Sound is produced at 78.9 (63.6-82.2) SPL rms re 2.10(-5) Pa with a peak at 99.2 (85.7-104.6) SPL re 2.10(-5) Pa estimated at a distance of one metre. This energy output is significant considering the small size of the insect. When scaled to body length and compared to 227 other acoustic species, the acoustic energy produced by M. scholtzi appears as an extreme value, outperforming marine and terrestrial mammal vocalisations. Such an extreme display may be interpreted as an exaggerated secondary sexual trait resulting from a runaway sexual selection without predation pressure.

So small, so loud: extremely high sound pressure level from a pygmy aquatic insect (Corixidae, Micronectinae.

Directory of Open Access Journals (Sweden)

Jérôme Sueur

Full Text Available To communicate at long range, animals have to produce intense but intelligible signals. This task might be difficult to achieve due to mechanical constraints, in particular relating to body size. Whilst the acoustic behaviour of large marine and terrestrial animals has been thoroughly studied, very little is known about the sound produced by small arthropods living in freshwater habitats. Here we analyse for the first time the calling song produced by the male of a small insect, the water boatman Micronecta scholtzi. The song is made of three distinct parts differing in their temporal and amplitude parameters, but not in their frequency content. Sound is produced at 78.9 (63.6-82.2 SPL rms re 2.10(-5 Pa with a peak at 99.2 (85.7-104.6 SPL re 2.10(-5 Pa estimated at a distance of one metre. This energy output is significant considering the small size of the insect. When scaled to body length and compared to 227 other acoustic species, the acoustic energy produced by M. scholtzi appears as an extreme value, outperforming marine and terrestrial mammal vocalisations. Such an extreme display may be interpreted as an exaggerated secondary sexual trait resulting from a runaway sexual selection without predation pressure.

Mars' Surface Radiation Environment Measured with the Mars Science Laboratory's Curiosity Rover

Science.gov (United States)

Hassler, Donald M.; Zeitlin, Cary; Wimmer-Schweingruber, Robert F.; Ehresmann, Bent; Rafkin, Scot; Eigenbrode, Jennifer L.; Brinza, David E.; Weigle, Gerald; Böttcher, Stephan; Böhm, Eckart; Burmeister, Soenke; Guo, Jingnan; Köhler, Jan; Martin, Cesar; Reitz, Guenther; Cucinotta, Francis A.; Kim, Myung-Hee; Grinspoon, David; Bullock, Mark A.; Posner, Arik; Gómez-Elvira, Javier; Vasavada, Ashwin; Grotzinger, John P.; MSL Science Team; Kemppinen, Osku; Cremers, David; Bell, James F.; Edgar, Lauren; Farmer, Jack; Godber, Austin; Wadhwa, Meenakshi; Wellington, Danika; McEwan, Ian; Newman, Claire; Richardson, Mark; Charpentier, Antoine; Peret, Laurent; King, Penelope; Blank, Jennifer; Schmidt, Mariek; Li, Shuai; Milliken, Ralph; Robertson, Kevin; Sun, Vivian; Baker, Michael; Edwards, Christopher; Ehlmann, Bethany; Farley, Kenneth; Griffes, Jennifer; Miller, Hayden; Newcombe, Megan; Pilorget, Cedric; Rice, Melissa; Siebach, Kirsten; Stack, Katie; Stolper, Edward; Brunet, Claude; Hipkin, Victoria; Léveillé, Richard; Marchand, Geneviève; Sánchez, Pablo Sobrón; Favot, Laurent; Cody, George; Steele, Andrew; Flückiger, Lorenzo; Lees, David; Nefian, Ara; Martin, Mildred; Gailhanou, Marc; Westall, Frances; Israël, Guy; Agard, Christophe; Baroukh, Julien; Donny, Christophe; Gaboriaud, Alain; Guillemot, Philippe; Lafaille, Vivian; Lorigny, Eric; Paillet, Alexis; Pérez, René; Saccoccio, Muriel; Yana, Charles; Armiens-Aparicio, Carlos; Rodríguez, Javier Caride; Blázquez, Isaías Carrasco; Gómez, Felipe Gómez; Hettrich, Sebastian; Malvitte, Alain Lepinette; Jiménez, Mercedes Marín; Martínez-Frías, Jesús; Martín-Soler, Javier; Martín-Torres, F. Javier; Jurado, Antonio Molina; Mora-Sotomayor, Luis; Caro, Guillermo Muñoz; López, Sara Navarro; Peinado-González, Verónica; Pla-García, Jorge; Manfredi, José Antonio Rodriguez; Romeral-Planelló, Julio José; Fuentes, Sara Alejandra Sans; Martinez, Eduardo Sebastian; Redondo, Josefina Torres; Urqui-O'Callaghan, Roser; Mier, María-Paz Zorzano; Chipera, Steve; Lacour, Jean-Luc; Mauchien, Patrick; Sirven, Jean-Baptiste; Manning, Heidi; Fairén, Alberto; Hayes, Alexander; Joseph, Jonathan; Squyres, Steven; Sullivan, Robert; Thomas, Peter; Dupont, Audrey; Lundberg, Angela; Melikechi, Noureddine; Mezzacappa, Alissa; Berger, Thomas; Matthia, Daniel; Prats, Benito; Atlaskin, Evgeny; Genzer, Maria; Harri, Ari-Matti; Haukka, Harri; Kahanpää, Henrik; Kauhanen, Janne; Kemppinen, Osku; Paton, Mark; Polkko, Jouni; Schmidt, Walter; Siili, Tero; Fabre, Cécile; Wray, James; Wilhelm, Mary Beth; Poitrasson, Franck; Patel, Kiran; Gorevan, Stephen; Indyk, Stephen; Paulsen, Gale; Gupta, Sanjeev; Bish, David; Schieber, Juergen; Gondet, Brigitte; Langevin, Yves; Geffroy, Claude; Baratoux, David; Berger, Gilles; Cros, Alain; d'Uston, Claude; Forni, Olivier; Gasnault, Olivier; Lasue, Jérémie; Lee, Qiu-Mei; Maurice, Sylvestre; Meslin, Pierre-Yves; Pallier, Etienne; Parot, Yann; Pinet, Patrick; Schröder, Susanne; Toplis, Mike; Lewin, Éric; Brunner, Will; Heydari, Ezat; Achilles, Cherie; Oehler, Dorothy; Sutter, Brad; Cabane, Michel; Coscia, David; Israël, Guy; Szopa, Cyril; Dromart, Gilles; Robert, François; Sautter, Violaine; Le Mouélic, Stéphane; Mangold, Nicolas; Nachon, Marion; Buch, Arnaud; Stalport, Fabien; Coll, Patrice; François, Pascaline; Raulin, François; Teinturier, Samuel; Cameron, James; Clegg, Sam; Cousin, Agnès; DeLapp, Dorothea; Dingler, Robert; Jackson, Ryan Steele; Johnstone, Stephen; Lanza, Nina; Little, Cynthia; Nelson, Tony; Wiens, Roger C.; Williams, Richard B.; Jones, Andrea; Kirkland, Laurel; Treiman, Allan; Baker, Burt; Cantor, Bruce; Caplinger, Michael; Davis, Scott; Duston, Brian; Edgett, Kenneth; Fay, Donald; Hardgrove, Craig; Harker, David; Herrera, Paul; Jensen, Elsa; Kennedy, Megan R.; Krezoski, Gillian; Krysak, Daniel; Lipkaman, Leslie; Malin, Michael; McCartney, Elaina; McNair, Sean; Nixon, Brian; Posiolova, Liliya; Ravine, Michael; Salamon, Andrew; Saper, Lee; Stoiber, Kevin; Supulver, Kimberley; Van Beek, Jason; Van Beek, Tessa; Zimdar, Robert; French, Katherine Louise; Iagnemma, Karl; Miller, Kristen; Summons, Roger; Goesmann, Fred; Goetz, Walter; Hviid, Stubbe; Johnson, Micah; Lefavor, Matthew; Lyness, Eric; Breves, Elly; Dyar, M. Darby; Fassett, Caleb; Blake, David F.; Bristow, Thomas; DesMarais, David; Edwards, Laurence; Haberle, Robert; Hoehler, Tori; Hollingsworth, Jeff; Kahre, Melinda; Keely, Leslie; McKay, Christopher; Wilhelm, Mary Beth; Bleacher, Lora; Brinckerhoff, William; Choi, David; Conrad, Pamela; Dworkin, Jason P.; Floyd, Melissa; Freissinet, Caroline; Garvin, James; Glavin, Daniel; Harpold, Daniel; Jones, Andrea; Mahaffy, Paul; Martin, David K.; McAdam, Amy; Pavlov, Alexander; Raaen, Eric; Smith, Michael D.; Stern, Jennifer; Tan, Florence; Trainer, Melissa; Meyer, Michael; Voytek, Mary; Anderson, Robert C.; Aubrey, Andrew; Beegle, Luther W.; Behar, Alberto; Blaney, Diana; Calef, Fred; Christensen, Lance; Crisp, Joy A.; DeFlores, Lauren; Ehlmann, Bethany; Feldman, Jason; Feldman, Sabrina; Flesch, Gregory; Hurowitz, Joel; Jun, Insoo; Keymeulen, Didier; Maki, Justin; Mischna, Michael; Morookian, John Michael; Parker, Timothy; Pavri, Betina; Schoppers, Marcel; Sengstacken, Aaron; Simmonds, John J.; Spanovich, Nicole; Juarez, Manuel de la Torre; Webster, Christopher R.; Yen, Albert; Archer, Paul Douglas; Jones, John H.; Ming, Douglas; Morris, Richard V.; Niles, Paul; Rampe, Elizabeth; Nolan, Thomas; Fisk, Martin; Radziemski, Leon; Barraclough, Bruce; Bender, Steve; Berman, Daniel; Dobrea, Eldar Noe; Tokar, Robert; Vaniman, David; Williams, Rebecca M. E.; Yingst, Aileen; Lewis, Kevin; Leshin, Laurie; Cleghorn, Timothy; Huntress, Wesley; Manhès, Gérard; Hudgins, Judy; Olson, Timothy; Stewart, Noel; Sarrazin, Philippe; Grant, John; Vicenzi, Edward; Wilson, Sharon A.; Hamilton, Victoria; Peterson, Joseph; Fedosov, Fedor; Golovin, Dmitry; Karpushkina, Natalya; Kozyrev, Alexander; Litvak, Maxim; Malakhov, Alexey; Mitrofanov, Igor; Mokrousov, Maxim; Nikiforov, Sergey; Prokhorov, Vasily; Sanin, Anton; Tretyakov, Vladislav; Varenikov, Alexey; Vostrukhin, Andrey; Kuzmin, Ruslan; Clark, Benton; Wolff, Michael; McLennan, Scott; Botta, Oliver; Drake, Darrell; Bean, Keri; Lemmon, Mark; Schwenzer, Susanne P.; Anderson, Ryan B.; Herkenhoff, Kenneth; Lee, Ella Mae; Sucharski, Robert; Hernández, Miguel Ángel de Pablo; Ávalos, Juan José Blanco; Ramos, Miguel; Malespin, Charles; Plante, Ianik; Muller, Jan-Peter; Navarro-González, Rafael; Ewing, Ryan; Boynton, William; Downs, Robert; Fitzgibbon, Mike; Harshman, Karl; Morrison, Shaunna; Dietrich, William; Kortmann, Onno; Palucis, Marisa; Sumner, Dawn Y.; Williams, Amy; Lugmair, Günter; Wilson, Michael A.; Rubin, David; Jakosky, Bruce; Balic-Zunic, Tonci; Frydenvang, Jens; Jensen, Jaqueline Kløvgaard; Kinch, Kjartan; Koefoed, Asmus; Madsen, Morten Bo; Stipp, Susan Louise Svane; Boyd, Nick; Campbell, John L.; Gellert, Ralf; Perrett, Glynis; Pradler, Irina; VanBommel, Scott; Jacob, Samantha; Owen, Tobias; Rowland, Scott; Atlaskin, Evgeny; Savijärvi, Hannu; García, César Martín; Mueller-Mellin, Reinhold; Bridges, John C.; McConnochie, Timothy; Benna, Mehdi; Franz, Heather; Bower, Hannah; Brunner, Anna; Blau, Hannah; Boucher, Thomas; Carmosino, Marco; Atreya, Sushil; Elliott, Harvey; Halleaux, Douglas; Rennó, Nilton; Wong, Michael; Pepin, Robert; Elliott, Beverley; Spray, John; Thompson, Lucy; Gordon, Suzanne; Newsom, Horton; Ollila, Ann; Williams, Joshua; Vasconcelos, Paulo; Bentz, Jennifer; Nealson, Kenneth; Popa, Radu; Kah, Linda C.; Moersch, Jeffrey; Tate, Christopher; Day, Mackenzie; Kocurek, Gary; Hallet, Bernard; Sletten, Ronald; Francis, Raymond; McCullough, Emily; Cloutis, Ed; ten Kate, Inge Loes; Kuzmin, Ruslan; Arvidson, Raymond; Fraeman, Abigail; Scholes, Daniel; Slavney, Susan; Stein, Thomas; Ward, Jennifer; Berger, Jeffrey; Moores, John E.

2014-01-01

The Radiation Assessment Detector (RAD) on the Mars Science Laboratory's Curiosity rover began making detailed measurements of the cosmic ray and energetic particle radiation environment on the surface of Mars on 7 August 2012. We report and discuss measurements of the absorbed dose and dose equivalent from galactic cosmic rays and solar energetic particles on the martian surface for ~300 days of observations during the current solar maximum. These measurements provide insight into the radiation hazards associated with a human mission to the surface of Mars and provide an anchor point with which to model the subsurface radiation environment, with implications for microbial survival times of any possible extant or past life, as well as for the preservation of potential organic biosignatures of the ancient martian environment.

Mars' surface radiation environment measured with the Mars Science Laboratory's Curiosity rover.

Science.gov (United States)

Hassler, Donald M; Zeitlin, Cary; Wimmer-Schweingruber, Robert F; Ehresmann, Bent; Rafkin, Scot; Eigenbrode, Jennifer L; Brinza, David E; Weigle, Gerald; Böttcher, Stephan; Böhm, Eckart; Burmeister, Soenke; Guo, Jingnan; Köhler, Jan; Martin, Cesar; Reitz, Guenther; Cucinotta, Francis A; Kim, Myung-Hee; Grinspoon, David; Bullock, Mark A; Posner, Arik; Gómez-Elvira, Javier; Vasavada, Ashwin; Grotzinger, John P

2014-01-24

The Radiation Assessment Detector (RAD) on the Mars Science Laboratory's Curiosity rover began making detailed measurements of the cosmic ray and energetic particle radiation environment on the surface of Mars on 7 August 2012. We report and discuss measurements of the absorbed dose and dose equivalent from galactic cosmic rays and solar energetic particles on the martian surface for ~300 days of observations during the current solar maximum. These measurements provide insight into the radiation hazards associated with a human mission to the surface of Mars and provide an anchor point with which to model the subsurface radiation environment, with implications for microbial survival times of any possible extant or past life, as well as for the preservation of potential organic biosignatures of the ancient martian environment.

Volatiles and Isotopes and the Exploration of Ancient and Modern Martian Habitability with the Curiosity Rover

Science.gov (United States)

Mhaffy, P. R.

2015-01-01

The Mars Science Laboratory Mission was designed to pave the way for the study of life beyond Earth through a search for a habitable environment in a carefully selected landing site on Mars. Its ongoing exploration of Gale Crater with the Curiosity Rover has provided a rich data set that revealed such an environment in an ancient lakebed [1]. Volatile and isotope measurements of both the atmosphere and solids contribute to our growing understanding of both modern and ancient environments.

Determination of foreign broadening coefficients for Methane Lines Targeted by the Tunable Laser Spectrometer (TLS) on the Mars Curiosity Rover

International Nuclear Information System (INIS)

Manne, Jagadeeshwari; Bui, Thinh Q.; Webster, Christopher R.

2017-01-01

Molecular line parameters of foreign- broadening by air, carbon dioxide, and helium gas have been experimentally determined for infrared ro-vibrational spectral lines of methane isotopologues ("1"2CH_4 and "1"3CH_4) at 3057 cm"−"1 targeted by the Tunable Laser Spectrometer (TLS) in the Sample Analysis at Mars (SAM) instrument suite on the Mars Science Laboratory (MSL) Curiosity rover. From multi-spectrum analyses with the speed-dependent Voigt line profile with Rosenkrantz line-mixing, speed-dependence and line-mixing effects were quantified for methane spectra at total pressures up to 200 mbar. The fitted air-broadening coefficients deviated from 8–25% to those reported in the HITRAN-2012 database. - Highlights: • Measurements of foreign broadening coefficients for Mars-TLS specific methane lines. • Spectral parameters were deduced from Speed-dependent Voigt profile with line mixing effects taken into account. • A thorough comparison of different line profile fits for the Mars-TLS methane lines. The fitted broadening coefficients and areas deviated up to 30% and 4%, respectively, when comparing the speed-dependent Voigt profile (with Rosenkrantz line-mixing) with the simplest Voigt profile. • Foreign broadening coefficients were measured within a precision of 2.2%.

Pressure sensor apparatus for indicating pressure in the body

International Nuclear Information System (INIS)

Hittman, F.; Fleischmann, L.W.

1981-01-01

A novel pressure sensor for indicating pressure in the body cavities of humans or animals is described in detail. The pressure sensor apparatus is relatively small and is easily implantable. It consists of a radioactive source (e.g. Pr-145, C-14, Ni-63, Sr-90 and Am-241) and associated radiation shielding and a bellows. The pressure acting upon the sensing tambour causes the bellows to expand and contract. This is turn causes the radiation shielding to move and changes in pressure can then be monitored external to the body using a conventional nuclear detector. The bellows is made of resilient material (e.g. gold plated nickel) and has a wall thickness of approximately 0.0003 inches. The apparatus is essentially insensitive to temperature variations. (U.K.)

How Small School Districts Can Organize to Afford Their Small Schools

Science.gov (United States)

Burton, Christine

2010-01-01

While the research continues to mount on the benefits of school downsizing and decentralizing efforts in urban areas, there exists a paradox for small school Administrators who continue to struggle against forces of consolidation. Small schools in rural and suburban districts have fought for their existence against the pressures of consolidation…

The Raman Laser Spectrometer for the ExoMars Rover Mission to Mars

Science.gov (United States)

Rull, Fernando; Maurice, Sylvestre; Hutchinson, Ian; Moral, Andoni; Perez, Carlos; Diaz, Carlos; Colombo, Maria; Belenguer, Tomas; Lopez-Reyes, Guillermo; Sansano, Antonio; Forni, Olivier; Parot, Yann; Striebig, Nicolas; Woodward, Simon; Howe, Chris; Tarcea, Nicolau; Rodriguez, Pablo; Seoane, Laura; Santiago, Amaia; Rodriguez-Prieto, Jose A.; Medina, Jesús; Gallego, Paloma; Canchal, Rosario; Santamaría, Pilar; Ramos, Gonzalo; Vago, Jorge L.; RLS Team

2017-07-01

The Raman Laser Spectrometer (RLS) on board the ESA/Roscosmos ExoMars 2020 mission will provide precise identification of the mineral phases and the possibility to detect organics on the Red Planet. The RLS will work on the powdered samples prepared inside the Pasteur analytical suite and collected on the surface and subsurface by a drill system. Raman spectroscopy is a well-known analytical technique based on the inelastic scattering by matter of incident monochromatic light (the Raman effect) that has many applications in laboratory and industry, yet to be used in space applications. Raman spectrometers will be included in two Mars rovers scheduled to be launched in 2020. The Raman instrument for ExoMars 2020 consists of three main units: (1) a transmission spectrograph coupled to a CCD detector; (2) an electronics box, including the excitation laser that controls the instrument functions; and (3) an optical head with an autofocus mechanism illuminating and collecting the scattered light from the spot under investigation. The optical head is connected to the excitation laser and the spectrometer by optical fibers. The instrument also has two targets positioned inside the rover analytical laboratory for onboard Raman spectral calibration. The aim of this article was to present a detailed description of the RLS instrument, including its operation on Mars. To verify RLS operation before launch and to prepare science scenarios for the mission, a simulator of the sample analysis chain has been developed by the team. The results obtained are also discussed. Finally, the potential of the Raman instrument for use in field conditions is addressed. By using a ruggedized prototype, also developed by our team, a wide range of terrestrial analog sites across the world have been studied. These investigations allowed preparing a large collection of real, in situ spectra of samples from different geological processes and periods of Earth evolution. On this basis, we are working

High pressure apparatus for hydrogen isotopes to pressures of 345 MPa (50,000 psi) and temperatures of 12000C

International Nuclear Information System (INIS)

Lakner, J.F.

1977-01-01

A functional new high pressure, high temperature apparatus for hydrogen isotopes uses an internally heated pressure vessel within a larger pressure vessel. The pressure capability is 345 MPa (50 K psi) at 1200 0 C. The gas pressure inside the internal vessel is balanced with gas pressure in the external vessel. The internal vessel is attached to a closure and is also the sample container. Our design allows thin-walled internal vessel construction and keeps the sample from ''seeing'' the furnace or other extraneous environment. The sample container together with the closure can easily be removed and loaded under argon using standard glove-box procedures. The small volume of the inner vessel permits small volumes of gas to be used, thus increasing the sensitivity during pressure-volume-temperature (PVT) work

Automated high pressure cell for pressure jump x-ray diffraction.

Science.gov (United States)

Brooks, Nicholas J; Gauthe, Beatrice L L E; Terrill, Nick J; Rogers, Sarah E; Templer, Richard H; Ces, Oscar; Seddon, John M

2010-06-01

A high pressure cell for small and wide-angle x-ray diffraction measurements of soft condensed matter samples has been developed, incorporating a fully automated pressure generating network. The system allows both static and pressure jump measurements in the range of 0.1-500 MPa. Pressure jumps can be performed as quickly as 5 ms, both with increasing and decreasing pressures. Pressure is generated by a motorized high pressure pump, and the system is controlled remotely via a graphical user interface to allow operation by a broad user base, many of whom may have little previous experience of high pressure technology. Samples are loaded through a dedicated port allowing the x-ray windows to remain in place throughout an experiment; this facilitates accurate subtraction of background scattering. The system has been designed specifically for use at beamline I22 at the Diamond Light Source, United Kingdom, and has been fully integrated with the I22 beamline control systems.

Automated high pressure cell for pressure jump x-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Brooks, Nicholas J.; Gauthe, Beatrice L. L. E.; Templer, Richard H.; Ces, Oscar; Seddon, John M. [Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Terrill, Nick J. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Rogers, Sarah E. [ISIS, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX (United Kingdom)

2010-06-15

A high pressure cell for small and wide-angle x-ray diffraction measurements of soft condensed matter samples has been developed, incorporating a fully automated pressure generating network. The system allows both static and pressure jump measurements in the range of 0.1-500 MPa. Pressure jumps can be performed as quickly as 5 ms, both with increasing and decreasing pressures. Pressure is generated by a motorized high pressure pump, and the system is controlled remotely via a graphical user interface to allow operation by a broad user base, many of whom may have little previous experience of high pressure technology. Samples are loaded through a dedicated port allowing the x-ray windows to remain in place throughout an experiment; this facilitates accurate subtraction of background scattering. The system has been designed specifically for use at beamline I22 at the Diamond Light Source, United Kingdom, and has been fully integrated with the I22 beamline control systems.

Automated high pressure cell for pressure jump x-ray diffraction

International Nuclear Information System (INIS)

Brooks, Nicholas J.; Gauthe, Beatrice L. L. E.; Templer, Richard H.; Ces, Oscar; Seddon, John M.; Terrill, Nick J.; Rogers, Sarah E.

2010-01-01

A high pressure cell for small and wide-angle x-ray diffraction measurements of soft condensed matter samples has been developed, incorporating a fully automated pressure generating network. The system allows both static and pressure jump measurements in the range of 0.1-500 MPa. Pressure jumps can be performed as quickly as 5 ms, both with increasing and decreasing pressures. Pressure is generated by a motorized high pressure pump, and the system is controlled remotely via a graphical user interface to allow operation by a broad user base, many of whom may have little previous experience of high pressure technology. Samples are loaded through a dedicated port allowing the x-ray windows to remain in place throughout an experiment; this facilitates accurate subtraction of background scattering. The system has been designed specifically for use at beamline I22 at the Diamond Light Source, United Kingdom, and has been fully integrated with the I22 beamline control systems.

Rim Structure, Stratigraphy, and Aqueous Alteration Exposures Along Opportunity Rover's Traverse of the Noachian Endeavour Crater

Science.gov (United States)

Crumpler, L.S.; Arvidson, R. E.; Golombek, M.; Grant, J. A.; Jolliff, B. L.; Mittlefehldt, D. W.

2017-01-01

The Mars Exploration Rover Opportunity has traversed 10.2 kilometers along segments of the west rim of the 22-kilometer-diameter Noachian Endeavour impact crater as of sol 4608 (01/09/17). The stratigraphy, attitude of units, lithology, and degradation state of bedrock outcrops exposed on the crater rim have been examined in situ and placed in geologic context. Structures within the rim and differences in physical properties of the identified lithologies have played important roles in localizing outcrops bearing evidence of aqueous alteration.

An Investigation of Organic and Inorganic Mercury Exposure and Blood Pressure in a Small-Scale Gold Mining Community in Ghana.

Science.gov (United States)

Rajaee, Mozhgon; Sánchez, Brisa N; Renne, Elisha P; Basu, Niladri

2015-08-21

There is increasing concern about the cardiovascular effects of mercury (Hg) exposure, and that organic methylmercury and inorganic Hg(2+) may affect the cardiovascular system and blood pressure differentially. In small-scale gold mining communities where inorganic, elemental Hg exposures are high, little is known about the effects of Hg on blood pressure. In 2011, we assessed the relationship between Hg exposure and blood pressure (BP) in a cross-sectional study of adults from a small-scale gold mining community, Kejetia, and subsistence farming community, Gorogo, in Ghana's Upper East Region. Participants' resting heart rate and BP were measured, and hair and urine samples were provided to serve as biomarkers of organic and inorganic Hg exposure, respectively. Participants included 70 miners and 26 non-miners from Kejetia and 75 non-miners from Gorogo. Total specific gravity-adjusted urinary and hair Hg was higher among Kejetia miners than Kejetia non-miners and Gorogo participants (median urinary Hg: 5.17, 1.18, and 0.154 µg/L, respectively; hair Hg: 0.945, 0.419, and 0.181 µg/g, respectively). Hypertension was prevalent in 17.7% of Kejetia and 21.3% of Gorogo participants. Urinary and hair Hg were not significantly associated with systolic or diastolic BP for Kejetia or Gorogo participants while adjusting for sex, age, and smoking status. Although our results follow trends seen in other studies, the associations were not of statistical significance. Given the unique study population and high exposures to inorganic Hg, the work contained here will help increase our understanding of the cardiovascular effects of Hg.

An Investigation of Organic and Inorganic Mercury Exposure and Blood Pressure in a Small-Scale Gold Mining Community in Ghana

Science.gov (United States)

Rajaee, Mozhgon; Sánchez, Brisa N.; Renne, Elisha P.; Basu, Niladri

2015-01-01

There is increasing concern about the cardiovascular effects of mercury (Hg) exposure, and that organic methylmercury and inorganic Hg2+ may affect the cardiovascular system and blood pressure differentially. In small-scale gold mining communities where inorganic, elemental Hg exposures are high, little is known about the effects of Hg on blood pressure. In 2011, we assessed the relationship between Hg exposure and blood pressure (BP) in a cross-sectional study of adults from a small-scale gold mining community, Kejetia, and subsistence farming community, Gorogo, in Ghana’s Upper East Region. Participants’ resting heart rate and BP were measured, and hair and urine samples were provided to serve as biomarkers of organic and inorganic Hg exposure, respectively. Participants included 70 miners and 26 non-miners from Kejetia and 75 non-miners from Gorogo. Total specific gravity-adjusted urinary and hair Hg was higher among Kejetia miners than Kejetia non-miners and Gorogo participants (median urinary Hg: 5.17, 1.18, and 0.154 µg/L, respectively; hair Hg: 0.945, 0.419, and 0.181 µg/g, respectively). Hypertension was prevalent in 17.7% of Kejetia and 21.3% of Gorogo participants. Urinary and hair Hg were not significantly associated with systolic or diastolic BP for Kejetia or Gorogo participants while adjusting for sex, age, and smoking status. Although our results follow trends seen in other studies, the associations were not of statistical significance. Given the unique study population and high exposures to inorganic Hg, the work contained here will help increase our understanding of the cardiovascular effects of Hg. PMID:26308023

Compositional variations in sands of the Bagnold Dunes, Gale crater, Mars, from visible-shortwave infrared spectroscopy and comparison with ground truth from the Curiosity rover

Science.gov (United States)

Lapotre, M. G. A.; Ehlmann, B. L.; Minson, S. E.; Arvidson, R. E.; Ayoub, F.; Fraeman, A. A.; Ewing, R. C.; Bridges, N. T.

2017-12-01

During its ascent up Mount Sharp, the Mars Science Laboratory Curiosity rover traversed the Bagnold Dune Field. We model sand modal mineralogy and grain size at four locations near the rover traverse, using orbital shortwave infrared single-scattering albedo spectra and a Markov chain Monte Carlo implementation of Hapke's radiative transfer theory to fully constrain uncertainties and permitted solutions. These predictions, evaluated against in situ measurements at one site from the Curiosity rover, show that X-ray diffraction-measured mineralogy of the basaltic sands is within the 95% confidence interval of model predictions. However, predictions are relatively insensitive to grain size and are nonunique, especially when modeling the composition of minerals with solid solutions. We find an overall basaltic mineralogy and show subtle spatial variations in composition in and around the Bagnold Dunes, consistent with a mafic enrichment of sands with cumulative aeolian-transport distance by sorting of olivine, pyroxene, and plagioclase grains. Furthermore, the large variations in Fe and Mg abundances ( 20 wt %) at the Bagnold Dunes suggest that compositional variability may be enhanced by local mixing of well-sorted sand with proximal sand sources. Our estimates demonstrate a method for orbital quantification of composition with rigorous uncertainty determination and provide key constraints for interpreting in situ measurements of compositional variability within Martian aeolian sandstones.

Compositional variations in sands of the Bagnold Dunes, Gale Crater, Mars, from visible-shortwave infrared spectroscopy and comparison with ground truth from the Curiosity Rover

Science.gov (United States)

Lapotre, Mathieu G.A.; Ehlmann, B. L.; Minson, Sarah E.; Arvidson, R. E.; Ayoub, F.; Fraeman, A. A.; Ewing, R. C.; Bridges, N. T.

2017-01-01

During its ascent up Mount Sharp, the Mars Science Laboratory Curiosity rover traversed the Bagnold Dune Field. We model sand modal mineralogy and grain size at four locations near the rover traverse, using orbital shortwave infrared single scattering albedo spectra and a Markov-Chain Monte Carlo implementation of Hapke's radiative transfer theory to fully constrain uncertainties and permitted solutions. These predictions, evaluated against in situ measurements at one site from the Curiosity rover, show that XRD-measured mineralogy of the basaltic sands is within the 95% confidence interval of model predictions. However, predictions are relatively insensitive to grain size and are non-unique, especially when modeling the composition of minerals with solid solutions. We find an overall basaltic mineralogy and show subtle spatial variations in composition in and around the Bagnold dunes, consistent with a mafic enrichment of sands with cumulative transport distance by sorting of olivine, pyroxene, and plagioclase grains during aeolian saltation. Furthermore, the large variations in Fe and Mg abundances (~20 wt%) at the Bagnold Dunes suggest that compositional variability induced by wind sorting may be enhanced by local mixing with proximal sand sources. Our estimates demonstrate a method for orbital quantification of composition with rigorous uncertainty determination and provide key constraints for interpreting in situ measurements of compositional variability within martian aeolian sandstones.

The development of a virtual camera system for astronaut-rover planetary exploration.

Science.gov (United States)

Platt, Donald W; Boy, Guy A

2012-01-01

A virtual assistant is being developed for use by astronauts as they use rovers to explore the surface of other planets. This interactive database, called the Virtual Camera (VC), is an interactive database that allows the user to have better situational awareness for exploration. It can be used for training, data analysis and augmentation of actual surface exploration. This paper describes the development efforts and Human-Computer Interaction considerations for implementing a first-generation VC on a tablet mobile computer device. Scenarios for use will be presented. Evaluation and success criteria such as efficiency in terms of processing time and precision situational awareness, learnability, usability, and robustness will also be presented. Initial testing and the impact of HCI design considerations of manipulation and improvement in situational awareness using a prototype VC will be discussed.

Overview of the magnetic properties experiments on the Mars Exploration Rovers

DEFF Research Database (Denmark)

Madsen, M. B.; Goetz, W.; Bertelsen, P.

2009-01-01

, while the weakly magnetic one is bright red. Images returned by the Microscopic Imager reveal the formation of magnetic chains diagnostic of magnetite-rich grains with substantial magnetization (>8 Am-2 kg(-1)). On the basis of Mossbauer spectra the dust contains magnetite, olivine, pyroxene......The Mars Exploration Rovers have accumulated airborne dust on different types of permanent magnets. Images of these magnets document the dynamics of dust capture and removal over time. The strongly magnetic subset of airborne dust appears dark brown to black in Panoramic Camera (Pancam) images......, and nanophase oxides in varying proportions, depending on wind regime and landing site. The dust contains a larger amount of ferric iron (Fe3+/Fe-tot similar to 0.6) than rocks in the Gusev plains (similar to 0.1-0.2) or average Gusev soil (similar to 0.3). Alpha Particle X-Ray Spectrometer data of the dust...

ATDM Rover Milestone Report STDA02-1 (FY2017 Q4)

Energy Technology Data Exchange (ETDEWEB)

Larsen, Matt [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Laney, Dan E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-10-19

We have successfully completed the MS-4/Y1 Milestone STDA02-1 for the Rover Project. This document describes the milestone and provides an overview of the technical details and artifacts of the milestone. This milestone is focused on building a GPU accelerated ray tracing package capable of doing multi-group radiography, both back-lit and with self-emission as well as serving as a volume rendering plot in VisIt and other VTK-based visualization tools. The long term goal is a package with in-situ capability, but for this first version integration into VisIt is the primary goal. Milestone Execution Plan: Create API for GPU Raytracer that supports multi-group transport (up to hundreds of groups); Implement components into one or more of: VTK-m, VisIt, and a new library/package implementation to be hosted on LLNL Bitbucket (initially), before releasing to the wider community.

Hydraulic High Pressure Valve Controller Using the In-Situ Pressure Difference

Science.gov (United States)

Bao, Xiaoqi (Inventor); Sherrit, Stewart (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Hall, Jeffery L. (Inventor)

2016-01-01

A hydraulic valve controller that uses an existing pressure differential as some or all of the power source for valve operation. In a high pressure environment, such as downhole in an oil or gas well, the pressure differential between the inside of a pipe and the outside of the pipe may be adequately large to drive a linear slide valve. The valve is operated hydraulically by a piston in a bore. When a higher pressure is applied to one end of the bore and a lower pressure to the other end, the piston moves in response to the pressure differential and drives a valve attached to it. If the pressure differential is too small to drive the piston at a sufficiently high speed, a pump is provided to generate a larger pressure differential to be applied. The apparatus is conveniently constructed using multiport valves, which can be rotary valves.

Abundance and Isotopic Composition of Gases in the Martian Atmosphere: First Results from the Mars Curiosity Rover

Science.gov (United States)

Mahaffy, Paul; Webster, Chris R.; Atreya, Sushil K.; Franz, Heather; Wong, Michael; Conrad, Pamela G.; Harpold, Dan; Jones, John J.; Leshin, Laurie, A.; Manning, Heidi;

Analysis of small deflection touch mode behavior in capacitive pressure sensors

DEFF Research Database (Denmark)

Fragiacomo, Giulio; Ansbæk, Thor; Pedersen, Thomas

2010-01-01

Due to an increasing need for devices with low power consumption, capacitive pressure sensors have become good substitutes for the well known piezoresistive pressure sensors. Mathematical models are necessary to design and characterize the device, preferably the model is analytical...... such that geometrical scalings are revealed. We show that, in the case of linear elastic behavior, a simple analytical model can be found for a touch mode capacitive pressure sensor (TMCPS). With this model it is possible to readily evaluate the main features of a TMCPS such as: sensitivity (both in normal and touch...... mode), touch point pressure and parasitic capacitance. Therefore, the desired device can be designed without using finite element modeling (FEM). This reduces the effort needed to design a micromachined TMCPS. Finally, the model has been compared with a micromachined TMCPS showing an excellent...

A compact led lidar system fitted for a mars rover – design and ground experiment

Directory of Open Access Journals (Sweden)

Ong Prane Mariel B.

2018-01-01

Full Text Available A compact LED lidar was constructed and fieldtested with the aim to observe the Mars’ dust devils. To be able to fit it on the Mars rover, a specialized Cassegrain telescope was designed to be within a 10 cm-cube, with a field of view of 3mrad. The transmitter has 385 nm LED light source with 3 cmϕ opening, 70mrad divergence, 0.75W (7.5nJ/10ns pulse power, and 500 kHz repetition frequency. The configuration of the optical system is biaxial to easily configure the overlap between their optical axes.

Miniature piezoresistive solid state integrated pressure sensors

Science.gov (United States)

Kahng, S. K.

1980-01-01

The characteristics of silicon pressure sensors with an ultra-small diaphragm are described. The pressure sensors utilize rectangular diaphragm as small as 0.0127 x 0.0254 cm and a p-type Wheatstone bridge consisting of diffused piezoresistive elements, 0.000254 cm by 0.00254 cm. These sensors exhibit as high as 0.5 MHz natural frequency and 1 mV/V/psi pressure sensitivity. Fabrication techniques and high frequency results from shock tube testing and low frequency comparison with microphones are presented.

Detection of small-amplitude periodic surface pressure fluctuation by pressure-sensitive paint measurements using frequency-domain methods

Science.gov (United States)

Noda, Takahiro; Nakakita, Kazuyki; Wakahara, Masaki; Kameda, Masaharu

2018-06-01

Image measurement using pressure-sensitive paint (PSP) is an effective tool for analyzing the unsteady pressure field on the surface of a body in a low-speed air flow, which is associated with wind noise. In this study, the surface pressure fluctuation due to the tonal trailing edge (TE) noise for a two-dimensional NACA 0012 airfoil was quantitatively detected using a porous anodized aluminum PSP (AA-PSP). The emission from the PSP upon illumination by a blue laser diode was captured using a 12-bit high-speed complementary metal-oxide-semiconductor (CMOS) camera. The intensities of the captured images were converted to pressures using a standard intensity-based method. Three image-processing methods based on the fast Fourier transform (FFT) were tested to determine their efficiency in improving the signal-to-noise ratio (SNR) of the unsteady PSP data. In addition to two fundamental FFT techniques (the full data and ensemble averaging FFTs), a technique using the coherent output power (COP), which involves the cross correlation between the PSP data and the signal measured using a pointwise sound-level meter, was tested. Preliminary tests indicated that random photon shot noise dominates the intensity fluctuations in the captured PSP emissions above 200 Hz. Pressure fluctuations associated with the TE noise, whose dominant frequency is approximately 940 Hz, were successfully measured by analyzing 40,960 sequential PSP images recorded at 10 kfps. Quantitative validation using the power spectrum indicates that the COP technique is the most effective method of identification of the pressure fluctuation directly related to TE noise. It is possible to distinguish power differences with a resolution of 10 Pa^2 (4 Pa in amplitude) when the COP was employed without use of another wind-off data. This resolution cannot be achieved by the ensemble averaging FFT because of an insufficient elimination of the background noise.

Method and Apparatus for Characterizing Pressure Sensors using Modulated Light Beam Pressure

Science.gov (United States)

Youngquist, Robert C. (Inventor)

2003-01-01

Embodiments of apparatuses and methods are provided that use light sources instead of sound sources for characterizing and calibrating sensors for measuring small pressures to mitigate many of the problems with using sound sources. In one embodiment an apparatus has a light source for directing a beam of light on a sensing surface of a pressure sensor for exerting a force on the sensing surface. The pressure sensor generates an electrical signal indicative of the force exerted on the sensing surface. A modulator modulates the beam of light. A signal processor is electrically coupled to the pressure sensor for receiving the electrical signal.

Electronically-Scanned Pressure Sensors

Science.gov (United States)

Coe, C. F.; Parra, G. T.; Kauffman, R. C.

1984-01-01

Sensors not pneumatically switched. Electronic pressure-transducer scanning system constructed in modular form. Pressure transducer modules and analog to digital converter module small enough to fit within cavities of average-sized wind-tunnel models. All switching done electronically. Temperature controlled environment maintained within sensor modules so accuracy maintained while ambient temperature varies.

Analysis of oligomeric transition of silkworm small heat shock protein sHSP20.8 using high hydrostatic pressure native PAGE

Science.gov (United States)

Fujisawa, Tetsuro; Ueda, Toshifumi; Kameyama, Keiichi; Aso, Yoichi; Ishiguro, Ryo

2013-06-01

The small heat shock proteins (sHSPs) solubilize thermo-denatured proteins without adenosine triphosphate energy consumption to facilitate protein refolding. sHSP20.8 is one of the silkworm (Bombyx mori) sHSPs having only one cystein in the N-terminal domain: Cys43. We report a simple measurement of oligomeric transition of sHSP20.8 using high hydrostatic pressure native polyacrylamide gel electrophoresis (high hydrostatic pressure (HP) native polyacrylamide gel electrophoresis (PAGE)). At ambient pressure under oxydative condition, the native PAGE of thermal transition of sHSP20.8 oligomer displayed a cooperative association. In contrast, HP native PAGE clearly demonstrated that sHSP20.8 dissociated at 80 MPa and 25°C, and the resultant molecular species gradually reassociated with time under that condition. In addition, the reassociation process was suppressed in the presence of the reductant. These results are consistent with the idea that sHSP20.8 oligomer temporally dissociates at the first thermo-sensing step and reassociates with the oxidation of Cys43.

An Investigation of Organic and Inorganic Mercury Exposure and Blood Pressure in a Small-Scale Gold Mining Community in Ghana

Directory of Open Access Journals (Sweden)

Mozhgon Rajaee

2015-08-01

Full Text Available There is increasing concern about the cardiovascular effects of mercury (Hg exposure, and that organic methylmercury and inorganic Hg2+ may affect the cardiovascular system and blood pressure differentially. In small-scale gold mining communities where inorganic, elemental Hg exposures are high, little is known about the effects of Hg on blood pressure. In 2011, we assessed the relationship between Hg exposure and blood pressure (BP in a cross-sectional study of adults from a small-scale gold mining community, Kejetia, and subsistence farming community, Gorogo, in Ghana’s Upper East Region. Participants’ resting heart rate and BP were measured, and hair and urine samples were provided to serve as biomarkers of organic and inorganic Hg exposure, respectively. Participants included 70 miners and 26 non-miners from Kejetia and 75 non-miners from Gorogo. Total specific gravity-adjusted urinary and hair Hg was higher among Kejetia miners than Kejetia non-miners and Gorogo participants (median urinary Hg: 5.17, 1.18, and 0.154 µg/L, respectively; hair Hg: 0.945, 0.419, and 0.181 µg/g, respectively. Hypertension was prevalent in 17.7% of Kejetia and 21.3% of Gorogo participants. Urinary and hair Hg were not significantly associated with systolic or diastolic BP for Kejetia or Gorogo participants while adjusting for sex, age, and smoking status. Although our results follow trends seen in other studies, the associations were not of statistical significance. Given the unique study population and high exposures to inorganic Hg, the work contained here will help increase our understanding of the cardiovascular effects of Hg.

Pressure-driven peristaltic flow

International Nuclear Information System (INIS)

Mingalev, S V; Lyubimov, D V; Lyubimova, T P

2013-01-01

The peristaltic motion of an incompressible fluid in two-dimensional channel is investigated. Instead of fixing the law of wall's coordinate variation, the law of pressure variation on the wall is fixed and the border's coordinate changes to provide the law of pressure variation on the wall. In case of small amplitude of pressure-variation on the wall A, expansion wave propagates along the length of channel and the wave results in the peristaltic transport of fluid. In the case of large A, the channel divides into two parts. The small pulsating part in the end of the tube creates the flow as a human heart, while the other big part loses this function. The solution of problem for the first peristaltic mode is stable, while the solution for the second 'heart' mode is unstable and depends heavily on boundary conditions.

Titan LEAF: A Sky Rover Granting Targeted Access to Titan's Lakes and Plains

Science.gov (United States)

Ross, Floyd; Lee, Greg; Sokol, Daniel; Goldman, Benjamin; Bolisay, Linden

2016-10-01

Northrop Grumman, in collaboration with L'Garde Inc. and Global Aerospace Corporation (GAC), has been developing the Titan Lifting Entry Atmospheric Flight (T-LEAF) sky rover to roam the atmosphere and observe at close quarters the lakes and plains of Titan. T-LEAF also supports surface exploration and science by providing precision delivery of in situ instruments to the surface.T-LEAF is a maneuverable, buoyant air vehicle. Its aerodynamic shape provides its maneuverability, and its internal helium envelope reduces propulsion power requirements and also the risk of crashing. Because of these features, T-LEAF is not restricted to following prevailing wind patterns. This freedom of mobility allows it be commanded to follow the shorelines of Titan's methane lakes, for example, or to target very specific surface locations.T-LEAF utilizes a variable power propulsion system, from high power at ~200W to low power at ~50W. High power mode uses the propellers and control surfaces for additional mobility and maneuverability. It also allows the vehicle to hover over specific locations for long duration surface observations. Low power mode utilizes GAC's Titan Winged Aerobot (TWA) concept, currently being developed with NASA funding, which achieves guided flight without the use of propellers or control surfaces. Although slower than high powered flight, this mode grants increased power to science instruments while still maintaining control over direction of travel.Additionally, T-LEAF is its own entry vehicle, with its leading edges protected by flexible thermal protection system (f-TPS) materials already being tested by NASA's Hypersonic Inflatable Aerodynamic Decelerator (HIAD) group. This f-TPS technology allows T-LEAF to inflate in space, like HIAD, and then enter the atmosphere fully deployed. This approach accommodates entry velocities from as low as ~1.8 km/s if entering from Titan orbit, up to ~6 km/s if entering directly from Saturn orbit, like the Huygens probe

Small-angle x-ray scattering and density measurements of liquid Se50-Te50 mixture at high temperatures and high pressures using synchrotron radiation

International Nuclear Information System (INIS)

Kajihara, Y; Inui, M; Matsuda, K; Tomioka, Y

2010-01-01

We have carried out small-angle x-ray scattering and x-ray transmission measurements of liquid Se 50 -Te 50 mixture at SPring-8 in Japan and obtained the structure factor S(Q) at small-Q region (0.6 -1 ) and the density at high temperatures and high pressures up to 1000 0 C and 180 MPa. We report preliminary results in this paper. With increasing temperature, the density shows a minimum at around 500 0 C and a maximum at around 700 0 C. On the other hand, S(0) becomes maximum and S(Q) strongly depends on Q at around 600 0 C, which is about the middle temperature where the density shows the minimum and maximum. The temperatures shift to lower side when the pressure increases. These results prove that, with increasing temperature, the sample exhibits gradual transition from low-density structure to high-density structure, which causes mesoscopic density fluctuations in the intermediate temperature region.

Pressure-flow relationships in in vitro model of compartment syndrome.

Science.gov (United States)

Shrier, I; Magder, S

1995-07-01

Compartment syndrome is a condition in which an increase in intramuscular pressure decreases blood flow to skeletal muscle. According to the Starling resistor (i.e., vascular waterfall) model of blood flow, the decrease in flow could occur through an increase in arterial resistance (Rart) or an increase in the critical closing pressure (Pcrit). To determine which explains the decrease in flow, we pump perfused a canine gastrocnemius muscle placed within an airtight box, controlled box pressures (Pbox) so that flow ranged from 100 to 50%, and measured Pcrit, Rart, arterial compliance, small venular pressure (measured by the double-occlusion technique), and venous pressure. An increase in Pbox limited flow mainly through an increase in Pcrit (75-85%), with only small changes in Rart (15-25%) and no change in arterial compliance. Increases in Pbox also produced a vascular waterfall in the venous circulation, but small venular transmural pressure always remained less than control levels. We conclude that increases in Pbox mostly limit blood flow through increases in Pcrit and that Rart plays a minor role. Transmural pressure across the small venules decreases with increases in intramuscular pressure, which contradicts the currently held belief that compartment syndrome is due to a cycle of swelling-ischemia-swelling.

Effect of hepatic venous sphincter contraction on transmission of central venous pressure to lobar and portal pressure.

Science.gov (United States)

Lautt, W W; Legare, D J; Greenway, C V

1987-11-01

In dogs anesthetized with pentobarbital, central vena caval pressure (CVP), portal venous pressure (PVP), and intrahepatic lobar venous pressure (proximal to the hepatic venous sphincters) were measured. The objective was to determine some characteristics of the intrahepatic vascular resistance sites (proximal and distal to the hepatic venous sphincters) including testing predictions made using a recent mathematical model of distensible hepatic venous resistance. The stimulus used was a brief rise in CVP produced by transient occlusion of the thoracic vena cava in control state and when vascular resistance was elevated by infusions of norepinephrine or histamine, or by nerve stimulation. The percent transmission of the downstream pressure rise to upstream sites past areas of vascular resistance was elevated. Even small increments in CVP are partially transmitted upstream. The data are incompatible with the vascular waterfall phenomenon which predicts that venous pressure increments are not transmitted upstream until a critical pressure is overcome and then further increments would be 100% transmitted. The hepatic sphincters show the following characteristics. First, small rises in CVP are transmitted less than large elevations; as the CVP rises, the sphincters passively distend and allow a greater percent transmission upstream, thus a large rise in CVP is more fully transmitted than a small rise in CVP. Second, the amount of pressure transmission upstream is determined by the vascular resistance across which the pressure is transmitted. As nerves, norepinephrine, or histamine cause the hepatic sphincters to contract, the percent transmission becomes less and the distensibility of the sphincters is reduced. Similar characteristics are shown for the "presinusoidal" vascular resistance and the hepatic venous sphincter resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

Mars Science Laboratory (MSL) - First Results of Pressure Observations

Science.gov (United States)

Harri, Ari-Matti; Kahanpää, Henrik; Kemppinen, Osku; Genzer, Maria; Gómez-Elvira, Javier; Haberle, Robert M.; Schmidt, Walter; Savijärvi, Hannu; Rodríquez-Manfredi, Jose Antonio; Rafkin, Scott; Polkko, Jouni; Richardson, Mark; Newman, Claire; de la Torre Juárez, Manuel; Martín-Torres, Javier; Paz Zorzano-Mier, Maria; Atlaskin, Evgeny; Kauhanen, Janne; Paton, Mark; Haukka, Harri

2013-04-01

The Mars Science laboratory (MSL) called Curiosity made a successful landing at Gale crater early August 2012. MSL has an environmental instrument package called the Rover Environmental Monitoring Station (REMS) as a part of its scientific payload. REMS comprises instrumentation for the observation of atmospheric pressure, temperature of the air, ground temperature, wind speed and direction, relative humidity, and UV measurements. The REMS instrument suite is described at length in [1]. We concentrate on describing the first results from the REMS pressure observations and comparison of the measurements with modeling results. The REMS pressure device is provided by the Finnish Meteorological Institute. It is based on silicon micro-machined capacitive pressure sensors developed by Vaisala Inc. The pressure device makes use of two transducer electronics sections placed on a single multi-layer PCB inside the REMS Instrument Control Unit (ICU) with a filter-protected ventilation inlet to the ambient atmosphere. The absolute accuracy of the pressure device (< 3 Pa) and zero-drift (< 1 Pa/year) enables the investigations of long term and seasonal cycles of the Martian atmosphere. The relative accuracy, or repeatability, in the diurnal time scale is < 1.5 Pa, less than 2 % of the observed diurnal pressure variation at the landing site. The pressure device has special sensors with very high precision (less than 0.2 Pa) that makes it a good tool to study short-term atmospheric phenomena, e.g., dust devils and other convective vortices. The observed MSL pressure data enable us to study both the long term and short-term phenomena of the Martian atmosphere. This would add knowledge of these phenomena to that gathered by earlier Mars missions and modeling experiments [2,3]. Pressure observations are revealing new information on the local atmosphere and climate at Gale crater, and will shed light on the mesoscale and micrometeorological phenomena. Pressure observations show also

Pore water pressure response to small and large openings in argillaceous rocks

International Nuclear Information System (INIS)

Garitte, B.; Gens, A.; Vaunat, J.; Armand, G.; Conil, N.

2012-01-01

Document available in extended abstract form only. In the last decade an important amount of piezometers have been installed in the Bure Underground Rock Laboratory (URL) in the vicinity of ongoing works involving gallery excavations and drilling of boreholes and alveoles both in the major and minor stress directions. Relatively far field piezometers (placed one to four diameters from the excavation wall) showed a qualitatively consistent response at different scales. Here, we investigate whether the pore water pressure response around openings of different scales may be up-scaled. An attempt is made to find a common set of parameters that explains quantitatively the rock response at the different scales. The mechanisms underlying the pore water pressure response around an underground opening are twofold. The first class of mechanisms is usually associated with nearly undrained behaviour and the related pore water pressure changes are induced by the stress redistribution triggered by the creation of the tunnel opening causing a reorientation of the principal stresses and influenced by the initial stress anisotropy. These pore water pressure changes are closely linked to the mechanical constitutive law of the rock and to the damage zone around the opening. The second class of mechanisms is related to the drainage of excess pore water pressure relative to a state governed by the atmospheric water pressure condition prescribed at gallery wall and the water flow law, usually Darcy's. Strong anisotropy effects on the hydraulic response of Callovo-Oxfordian Clay can be observed with reference to Figure 1 that shows the pore pressure response to the drilling of a 150 mm-diameter borehole performed to install a heater for the TER thermal experiment. The borehole is aligned with the major horizontal principal stress. Therefore, in principle, the stress state should be approximately isotropic in a cross section of the borehole. As a matter of fact, however, a degree of

A Study on the Small Punch Test for Fracture Strength Evaluation of CANDU Pressure Tube Embrittled by Hydrogen

International Nuclear Information System (INIS)

Nho, Seung Hwan; Ong, Jang Woo; Yu, Hyo Sun; Chung, Se Hi

1996-01-01

The purpose of this study is to investigate the usefulness of small punch(SP) test using miniaturized specimens as a method for fracture strength evaluation of CANDU pressure tube embrittled by hydrogen. According to the test results, the fracture strength evaluation as a function of hydrogen concentration at -196 .deg. C was much better than that at room temperature, as the difference of SP fracture energy(Esp) with hydrogen concentration was more significant at -196 .deg. C than at room temperature for the hydrogen concentration up to 300ppm-H. It was also observed that the peak of average AE energy, the cumulative average AE energy and the cumulative average AE energy per equivalent fracture, strain increased with the increase of hydrogen concentration. From the results of load-displacement behaviors, Esp behaviors, macro- and micro-SEM fractographs and AE test it has been concluded that the SP test method using miniaturized specimen(10mmx10mmx0.5mm) will be a useful test method to evaluate the fracture strength for CANDU pressure tube embrittled by hydrogen

Intermediate Leg SBLOCA - Long Lasting Pressure Transient

International Nuclear Information System (INIS)

Konjarek, D.; Bajs, T.; Vukovic, J.

2010-01-01

The basic phenomenology of Small Break Loss of Coolant Accident (SBLOCA) for PWR plant is described with focus on analysis of scenario in which reactor coolant pressure decreases below secondary system pressure. Best estimate light water reactor transient analysis code RELAP5/mod3.3 was used in calculation. Rather detailed model of the plant was used. The break occurs in intermediate leg on lowest elevation near pump suction. The size of the break is chosen to be small enough to cause cycling of safety valves (SVs) on steam generators (SGs) for some time, but, afterwards, it is large enough to remove decay heat through the break, causing cooling the secondary side. In this case of SBLOCA, when primary pressure decreases below secondary pressure, long lasting pressure transients with significant amplitude occur. Reasons for such behavior are explained.(author).

Containment for small pressurized water reactors

International Nuclear Information System (INIS)

Siler, W.C.; Marda, R.S.; Smith, W.R.

1977-01-01

Babcock and Wilcox Company has prepared studies under ERDA contract of small and intermediate size (313, 365 and 1200 MWt) PWR reactor plants, for industrial cogeneration or electric power generation. Studies and experience with nuclear plants in this size range indicate unfavorable economics. To offset this disadvantage, modular characteristics of an integral reactor and close-coupled vapor suppression containment have been exploited to shorten construction schedules and reduce construction costs. The resulting compact reactor/containment complex is illustrated. Economic studies to date indicate that the containment design and the innovative construction techniques developed to shorten erection schedules have been important factors in reducing estimated project costs, thus potentially making such smaller plants competetive with competing energy sources

A multitasking behavioral control system for the Robotic All Terrain Lunar Exploration Rover (RATLER)

Science.gov (United States)

Klarer, P.

1994-01-01

An alternative methodology for designing an autonomous navigation and control system is discussed. This generalized hybrid system is based on a less sequential and less anthropomorphic approach than that used in the more traditional artificial intelligence (AI) technique. The architecture is designed to allow both synchronous and asynchronous operations between various behavior modules. This is accomplished by intertask communications channels which implement each behavior module and each interconnection node as a stand-alone task. The proposed design architecture allows for construction of hybrid systems which employ both subsumption and traditional AI techniques as well as providing for a teleoperator's interface. Implementation of the architecture is planned for the prototype Robotic All Terrain Lunar Explorer Rover (RATLER) which is described briefly.

Characterisation of creep cavitation damage in a stainless steel pressure vessel using small angle neutron scattering

CERN Document Server

Bouchard, P J; Treimer, W

2002-01-01

Grain-boundary cavitation is the dominant failure mode associated with initiation of reheat cracking, which has been widely observed in austenitic stainless steel pressure vessels operating at temperatures within the creep range (>450 C). Small angle neutron scattering (SANS) experiments at the LLB PAXE instrument (Saclay) and the V12 double-crystal diffractometer of the HMI-BENSC facility (Berlin) are used to characterise cavitation damage (in the size range R=10-2000 nm) in a variety of creep specimens extracted from ex-service plant. Factors that affect the evolution of cavities and the cavity-size distribution are discussed. The results demonstrate that SANS techniques have the potential to quantify the development of creep damage in type-316H stainless steel, and thereby link microstructural damage with ductility-exhaustion models of reheat cracking. (orig.)

Experimental evidence for negative turgor pressure in small leaf cells of Robinia pseudoacacia L versus large cells of Metasequoia glyptostroboides Hu et W.C.Cheng. 1. Evidence from pressure-volume curve analysis of dead tissue.

Science.gov (United States)

Yang, Dongmei; Pan, Shaoan; Ding, Yiting; Tyree, Melvin T

2017-03-01

This paper provides a mini-review of evidence for negative turgor pressure in leaf cells starting with experimental evidence in the late 1950s and ending with biomechanical models published in 2014. In the present study, biomechanical models were used to predict how negative turgor pressure might be manifested in dead tissue, and experiments were conducted to test the predictions. The main findings were as follows: (i) Tissues killed by heating to 60 or 80 °C or by freezing in liquid nitrogen all became equally leaky to cell sap solutes and all seemed to pass freely through the cell walls. (ii) Once cell sap solutes could freely pass the cell walls, the shape of pressure-volume curves was dramatically altered between living and dead cells. (iii) Pressure-volume curves of dead tissue seem to measure negative turgor defined as negative when inside minus outside pressure is negative. (iv) Robinia pseudoacacia leaves with small palisade cells had more negative turgor than Metasequoia glyptostroboides with large cells. (v) The absolute difference in negative turgor between R. pseudoacacia and M. glyptostroboides approached as much as 1.0 MPa in some cases. The differences in the manifestation of negative turgor in living versus dead tissue are discussed. © 2016 John Wiley & Sons Ltd.

Search for life on Mars in surface samples: Lessons from the 1999 Marsokhod rover field experiment

Science.gov (United States)

Newsom, Horton E.; Bishop, J.L.; Cockell, C.; Roush, T.L.; Johnson, J. R.

2001-01-01

The Marsokhod 1999 field experiment in the Mojave Desert included a simulation of a rover-based sample selection mission. As part of this mission, a test was made of strategies and analytical techniques for identifying past or present life in environments expected to be present on Mars. A combination of visual clues from high-resolution images and the detection of an important biomolecule (chlorophyll) with visible/near-infrared (NIR) spectroscopy led to the successful identification of a rock with evidence of cryptoendolithic organisms. The sample was identified in high-resolution images (3 times the resolution of the Imager for Mars Pathfinder camera) on the basis of a green tinge and textural information suggesting the presence of a thin, partially missing exfoliating layer revealing the organisms. The presence of chlorophyll bands in similar samples was observed in visible/NIR spectra of samples in the field and later confirmed in the laboratory using the same spectrometer. Raman spectroscopy in the laboratory, simulating a remote measurement technique, also detected evidence of carotenoids in samples from the same area. Laboratory analysis confirmed that the subsurface layer of the rock is inhabited by a community of coccoid Chroococcidioposis cyanobacteria. The identification of minerals in the field, including carbonates and serpentine, that are associated with aqueous processes was also demonstrated using the visible/NIR spectrometer. Other lessons learned that are applicable to future rover missions include the benefits of web-based programs for target selection and for daily mission planning and the need for involvement of the science team in optimizing image compression schemes based on the retention of visual signature characteristics. Copyright 2000 by the American Geophysical Union.

Use of Geochemistry Data Collected by the Mars Exploration Rover Spirit in Gusev Crater to Teach Geomorphic Zonation through Principal Components Analysis

Science.gov (United States)

Rodrigue, Christine M.

2011-01-01

This paper presents a laboratory exercise used to teach principal components analysis (PCA) as a means of surface zonation. The lab was built around abundance data for 16 oxides and elements collected by the Mars Exploration Rover Spirit in Gusev Crater between Sol 14 and Sol 470. Students used PCA to reduce 15 of these into 3 components, which,…

High-Performance Pressure Sensor for Monitoring Mechanical Vibration and Air Pressure

Directory of Open Access Journals (Sweden)

Yancheng Meng

2018-05-01

Full Text Available To realize the practical applications of flexible pressure sensors, the high performance (sensitivity and response time as well as more functionalities are highly desired. In this work, we fabricated a piezoresistive pressure sensor based on the micro-structured composites films of multi-walled carbon nanotubes (MWCNTs and poly (dimethylsiloxane (PDMS. In addition, we establish efficient strategies to improve key performance of our pressure sensor. Its sensitivity is improved up to 474.13 kPa−1 by minimizing pressure independent resistance of sensor, and response time is shorten as small as 2 μs by enhancing the elastic modulus of polymer elastomer. Benefiting from the high performance, the functionalities of sensors are successfully extended to the accurate detection of high frequency mechanical vibration (~300 Hz and large range of air pressure (6–101 kPa, both of which are not achieved before.

Pore Characterization of Shale Rock and Shale Interaction with Fluids at Reservoir Pressure-Temperature Conditions Using Small-Angle Neutron Scattering

Science.gov (United States)

Ding, M.; Hjelm, R.; Watkins, E.; Xu, H.; Pawar, R.

2015-12-01

Oil/gas produced from unconventional reservoirs has become strategically important for the US domestic energy independence. In unconventional realm, hydrocarbons are generated and stored in nanopores media ranging from a few to hundreds of nanometers. Fundamental knowledge of coupled thermo-hydro-mechanical-chemical (THMC) processes that control fluid flow and propagation within nano-pore confinement is critical for maximizing unconventional oil/gas production. The size and confinement of the nanometer pores creates many complex rock-fluid interface interactions. It is imperative to promote innovative experimental studies to decipher physical and chemical processes at the nanopore scale that govern hydrocarbon generation and mass transport of hydrocarbon mixtures in tight shale and other low permeability formations at reservoir pressure-temperature conditions. We have carried out laboratory investigations exploring quantitative relationship between pore characteristics of the Wolfcamp shale from Western Texas and the shale interaction with fluids at reservoir P-T conditions using small-angle neutron scattering (SANS). We have performed SANS measurements of the shale rock in single fluid (e.g., H2O and D2O) and multifluid (CH4/(30% H2O+70% D2O)) systems at various pressures up to 20000 psi and temperature up to 150 oF. Figure 1 shows our SANS data at different pressures with H2O as the pressure medium. Our data analysis using IRENA software suggests that the principal changes of pore volume in the shale occurred on smaller than 50 nm pores and pressure at 5000 psi (Figure 2). Our results also suggest that with increasing P, more water flows into pores; with decreasing P, water is retained in the pores.

Experimental Shock Transformation of Gypsum to Anhydrite: A New Low Pressure Regime Shock Indicator

Science.gov (United States)

Bell, Mary S.; Zolensky, Michael E.

2011-01-01

The shock behavior of gypsum is important in understanding the Cretaceous/Paleogene event and other terrestrial impacts that contain evaporite sediments in their targets (e.g., Mars Exploration Rover Spirit detected sulfate at Gusev crater, [1]). Most interest focuses on issues of devolatilization to quantify the production of SO2 to better understand its role in generating a temporary atmosphere and its effects on climate and biota [2,3]. Kondo and Ahrens [4] measured induced radiation emitted from single crystal gypsum shocked to 30 and 40 GPa. They observed greybody emission spectra corresponding to temperatures in the range of 3,000 to 4,000 K that are a factor of 2 to 10 times greater than calculated pressure-density energy equation of state temperatures (Hugoniot) and are high enough to melt gypsum. Chen et al. [5] reported results of shock experiments on anhydrite, gypsum, and mixtures of these phases with silica. Their observations indicated little or no devolatilization of anhydrite shocked to 42 GPa and that the fraction of sulfur, by mass, that degassed is approx.10(exp -2) of theoretical prediction. In another report of shock experiments on calcite, anhydrite, and gypsum, Badjukov et al. [6] observed only intensive plastic deformation in anhydrite shock loaded at 63 GPa, and gypsum converted to anhydrite when shock loaded at 56 GPa but have not experimentally shocked gypsum in a step-wise manner to constrain possible incipient transformation effects. Schmitt and Hornemann [7] shock loaded anhydrite and quartz to a peak pressure of 60 GPa and report the platy anhydrite grains were completely pseudomorphed by small crystallized anhydrite grains. However, no evidence of interaction between the two phases could be observed and they suggested that recrystallization of anhydrite grains is the result of a solid-state transformation. They concluded that significant decomposition of anhydrite requires shock pressures higher than 60 GPa. Gupta et al. [8

Predicting crack instability behavior of burst tests from small specimens for irradiated Zr-2.5Nb pressure tubes

International Nuclear Information System (INIS)

Davies, P.H.

1997-01-01

A scaling approach, based on the deformation J-integral at maximum load obtained from small specimens, is proposed for predicting the crack instability behavior of burst tests on irradiated Zr-2.5Nb pressure tubes. An assessment of this approach is carried out by comparison with other toughness criteria such as the modified J-integral and the plastic work dissipation rate approach. The largest discrepancy between the different parameters occurs for materials of intermediate toughness which exhibit the most stable crack growth and tunnelling up to maximum load. A study of one material of intermediate toughness suggests crack-front tunnelling has a significant influence on the results obtained from the 17-mm-wide specimens. It is shown that for a tube of intermediate toughness the different approaches can significantly underpredict the extent of stable crack growth before instability in a burst test even after correcting for tunnelling. The usefulness of a scaling approach in reducing the discrepancy between the small- and large-scale specimen results for this material is demonstrated

A multitasking behavioral control system for the Robotic All-Terrain Lunar Exploration Rover (RATLER)

Science.gov (United States)

Klarer, Paul

1993-01-01

An approach for a robotic control system which implements so called 'behavioral' control within a realtime multitasking architecture is proposed. The proposed system would attempt to ameliorate some of the problems noted by some researchers when implementing subsumptive or behavioral control systems, particularly with regard to multiple processor systems and realtime operations. The architecture is designed to allow synchronous operations between various behavior modules by taking advantage of a realtime multitasking system's intertask communications channels, and by implementing each behavior module and each interconnection node as a stand-alone task. The potential advantages of this approach over those previously described in the field are discussed. An implementation of the architecture is planned for a prototype Robotic All Terrain Lunar Exploration Rover (RATLER) currently under development and is briefly described.

Pressurized subsampling system for pressured gas-hydrate-bearing sediment: Microscale imaging using X-ray computed tomography

International Nuclear Information System (INIS)

Jin, Yusuke; Konno, Yoshihiro; Nagao, Jiro

2014-01-01

A pressurized subsampling system was developed for pressured gas hydrate (GH)-bearing sediments, which have been stored under pressure. The system subsamples small amounts of GH sediments from cores (approximately 50 mm in diameter and 300 mm in height) without pressure release to atmospheric conditions. The maximum size of the subsamples is 12.5 mm in diameter and 20 mm in height. Moreover, our system transfers the subsample into a pressure vessel, and seals the pressure vessel by screwing in a plug under hydraulic pressure conditions. In this study, we demonstrated pressurized subsampling from artificial xenon-hydrate sediments and nondestructive microscale imaging of the subsample, using a microfocus X-ray computed tomography (CT) system. In addition, we estimated porosity and hydrate saturation from two-dimensional X-ray CT images of the subsamples

Pressure induced deep tissue injury explained

NARCIS (Netherlands)

Oomens, C.W.J.; Bader, D.L.; Loerakker, S.; Baaijens, F.P.T.

The paper describes the current views on the cause of a sub-class of pressure ulcers known as pressure induced deep tissue injury (DTI). A multi-scale approach was adopted using model systems ranging from single cells in culture, tissue engineered muscle to animal studies with small animals. This

Optical Fibre Pressure Sensors in Medical Applications

Directory of Open Access Journals (Sweden)

Sven Poeggel

2015-07-01

Full Text Available This article is focused on reviewing the current state-of-the-art of optical fibre pressure sensors for medical applications. Optical fibres have inherent advantages due to their small size, immunity to electromagnetic interferences and their suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based pressure sensors, together with being lightweight and flexible, mean that they are minimally invasive for many medical applications and, thus, particularly suited to in vivo measurement. This means that the sensor can be placed directly inside a patient, e.g., for urodynamic and cardiovascular assessment. This paper presents an overview of the recent developments in optical fibre-based pressure measurements with particular reference to these application areas.

Optical Fibre Pressure Sensors in Medical Applications.

Science.gov (United States)

Poeggel, Sven; Tosi, Daniele; Duraibabu, DineshBabu; Leen, Gabriel; McGrath, Deirdre; Lewis, Elfed

2015-07-15

This article is focused on reviewing the current state-of-the-art of optical fibre pressure sensors for medical applications. Optical fibres have inherent advantages due to their small size, immunity to electromagnetic interferences and their suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based pressure sensors, together with being lightweight and flexible, mean that they are minimally invasive for many medical applications and, thus, particularly suited to in vivo measurement. This means that the sensor can be placed directly inside a patient, e.g., for urodynamic and cardiovascular assessment. This paper presents an overview of the recent developments in optical fibre-based pressure measurements with particular reference to these application areas.

Optical Fibre Pressure Sensors in Medical Applications

Science.gov (United States)

Poeggel, Sven; Tosi, Daniele; Duraibabu, DineshBabu; Leen, Gabriel; McGrath, Deirdre; Lewis, Elfed

2015-01-01

This article is focused on reviewing the current state-of-the-art of optical fibre pressure sensors for medical applications. Optical fibres have inherent advantages due to their small size, immunity to electromagnetic interferences and their suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based pressure sensors, together with being lightweight and flexible, mean that they are minimally invasive for many medical applications and, thus, particularly suited to in vivo measurement. This means that the sensor can be placed directly inside a patient, e.g., for urodynamic and cardiovascular assessment. This paper presents an overview of the recent developments in optical fibre-based pressure measurements with particular reference to these application areas. PMID:26184228

Wide Range Vacuum Pumps for the SAM Instrument on the MSL Curiosity Rover

Science.gov (United States)

Sorensen, Paul; Kline-Schoder, Robert; Farley, Rodger

2014-01-01

Creare Incorporated and NASA Goddard Space Flight Center developed and space qualified two wide range pumps (WRPs) that were included in the Sample Analysis at Mars (SAM) instrument. This instrument was subsequently integrated into the Mars Science Laboratory (MSL) "Curiosity Rover," launched aboard an Atlas V rocket in 2011, and landed on August 6, 2012, in the Gale Crater on Mars. The pumps have now operated for more than 18 months in the Gale Crater and have been evacuating the key components of the SAM instrument: a quadrupole mass spectrometer, a tunable laser spectrometer, and six gas chromatograph columns. In this paper, we describe the main design challenges and the ways in which they were solved. This includes the custom design of a miniaturized, high-speed motor to drive the turbo drag pump rotor, analysis of rotor dynamics for super critical operation, and bearing/lubricant design/selection.

Laser-induced breakdown spectroscopy for space exploration applications: Influence of the ambient pressure on the calibration curves prepared from soil and clay samples

International Nuclear Information System (INIS)

Salle, Beatrice; Cremers, David A.; Maurice, Sylvestre; Wiens, Roger C.

2005-01-01

Recently, there has been an increasing interest in the laser-induced breakdown spectroscopy (LIBS) technique for stand-off detection of geological samples for use on landers and rovers to Mars, and for other space applications. For space missions, LIBS analysis capabilities must be investigated and instrumental development is required to take into account constraints such as size, weight, power and the effect of environmental atmosphere (pressure and ambient gas) on flight instrument performance. In this paper, we study the in-situ LIBS method at reduced pressure (7 Torr CO 2 to simulate the Martian atmosphere) and near vacuum (50 mTorr in air to begin to simulate the Moon or asteroids' pressure) as well as at atmospheric pressure in air (for Earth conditions and comparison). Here in-situ corresponds to distances on the order of 150 mm in contrast to stand-off analysis at distance of many meters. We show the influence of the ambient pressure on the calibration curves prepared from certified soil and clay pellets. In order to detect simultaneously all the elements commonly observed in terrestrial soils, we used an Echelle spectrograph. The results are discussed in terms of calibration curves, measurement precision, plasma light collection system efficiency and matrix effects

Analysis of the environmental conditions at Gale Crater from MSL/REMS measurements

Energy Technology Data Exchange (ETDEWEB)

Martinez, G.; Torre-Juarez, M. de la; Vicente-Retortillo, A.; Kemppinen, O.; Renno, N.; Lemmon, M.

2016-07-01

The environmental conditions at Gale Crater during the first 1160 sols of the Mars Science Laboratory (MSL) mission are assessed using measurements taken by the Rover Environmental Monitoring Station (REMS) on-board the MSL Curiosity rover. REMS is a suite of sensors developed to assess the environmental conditions along the rover traverse. In particular, REMS has been measuring atmospheric pressure, atmospheric and ground temperature, relative humidity, UV radiation flux and wind speed. Here we analyze processed data with the highest confidence possible of atmospheric pressure, atmospheric and ground temperature and relative humidity. In addition, we estimate the daily UV irradiation at the surface of Gale Crater using dust opacity values derived from the Mastcam instrument. REMS is still in operation, but it has already provided the most comprehensive coverage of surface environmental conditions recorded by a spacecraft landed on Mars. (Author)

Investigation of small break loss-of-coolant phenomena in a small scale nonnuclear test facility

International Nuclear Information System (INIS)

Cozzuol, J.M.; Fauble, T.J.; Harvego, E.A.

1980-01-01

A small-scale nonnuclear integral test facility designed to simulate a pressurized water reactor (PWR) system was used to evaluate the effects of a small break loss-of-coolant accident (LOCA) on the system thermal-hydraulic response. The experiment approximated a 2.5% (11-cm diameter) communicative break in the cold leg of a PWR, and included initial conditions which were similar to conditions in a PWR operating at full power. The 2.5% break size ensured that the nominal break flow rate was greater than the high pressure injection system (HPIS) flow rate, thus providing the potential for a continuous system depressurization. The sequence of events was similar to that used in evaluation model analysis of small break loss-of-coolant accidents, and included simulated reactor scram and loss of offsite power. Comparisions of experimental data with computer code calculations are used to demonstrate the capabilities and limitations of integral system calculations used to predict phenomena which can be important in the assessment of a small break LOCA in a PWR

Arterial pressure profile in patients with cirrhosis

DEFF Research Database (Denmark)

Henriksen, Jens H; Fuglsang, Stefan; Bendtsen, Flemming

2012-01-01

Patients with cirrhosis have cardiovascular dysfunction and altered mechanical properties of large and small arteries. This study was undertaken in order to analyze the arterial pressure curve in relation to mean arterial pressure level, stroke volume, and severity of liver disease....

Tests Of Array Of Flush Pressure Sensors

Science.gov (United States)

Larson, Larry J.; Moes, Timothy R.; Siemers, Paul M., III

1992-01-01

Report describes tests of array of pressure sensors connected to small orifices flush with surface of 1/7-scale model of F-14 airplane in wind tunnel. Part of effort to determine whether pressure parameters consisting of various sums, differences, and ratios of measured pressures used to compute accurately free-stream values of stagnation pressure, static pressure, angle of attack, angle of sideslip, and mach number. Such arrays of sensors and associated processing circuitry integrated into advanced aircraft as parts of flight-monitoring and -controlling systems.

Fundamental Studies of Transient, Atmospheric-Pressure, Small-Scale Plasmas

Science.gov (United States)

2017-01-23

C. Jiang, R. Heller, J. Lane, and K. H. Schoenbach, " Ozone -free nitric oxide production using an atmospheric pressure surface discharge – a way to...Electrostatic modeling and energy-dependent studies showed that the direct and indirect electron-induced processes in the pulsed plasma jet are responsible for...Coupled sliding discharges : a scalable nonthermal plasma system utilizing positive and negative streamers on DISTRIBUTION A: Distribution

Behaviour of the ASDEX pressure gauge at high neutral gas pressure and applications for ITER

International Nuclear Information System (INIS)

Scarabosio, A.; Haas, G.

2008-01-01

The ASDEX Pressure Gauge is, at present, the main candidate for in-vessel neutral pressure measurement in ITER. Although the APG output is found to saturate at around 15 Pa, below the ITER requirement of 20 Pa. We show, here, that with small modifications of the gauge geometry and potentials settings we can achieve satisfactory behaviour up to 30 Pa at 6 T

The Rover Environmental Monitoring Station Ground Temperature Sensor: A Pyrometer for Measuring Ground Temperature on Mars

Directory of Open Access Journals (Sweden)

Miguel Ramos

2010-10-01

Full Text Available We describe the parameters that drive the design and modeling of the Rover Environmental Monitoring Station (REMS Ground Temperature Sensor (GTS, an instrument aboard NASA’s Mars Science Laboratory, and report preliminary test results. REMS GTS is a lightweight, low-power, and low cost pyrometer for measuring the Martian surface kinematic temperature. The sensor’s main feature is its innovative design, based on a simple mechanical structure with no moving parts. It includes an in-flight calibration system that permits sensor recalibration when sensor sensitivity has been degraded by deposition of dust over the optics. This paper provides the first results of a GTS engineering model working in a Martian-like, extreme environment.

Simultaneous extraction and clean-up of polychlorinated biphenyls and their metabolites from small tissue samples using pressurized liquid extraction

Science.gov (United States)

Kania-Korwel, Izabela; Zhao, Hongxia; Norstrom, Karin; Li, Xueshu; Hornbuckle, Keri C.; Lehmler, Hans-Joachim

2008-01-01

A pressurized liquid extraction-based method for the simultaneous extraction and in situ clean-up of polychlorinated biphenyls (PCBs), hydroxylated (OH)-PCBs and methylsulfonyl (MeSO2)-PCBs from small (< 0.5 gram) tissue samples was developed and validated. Extraction of a laboratory reference material with hexane:dichloromethane:methanol (48:43:9, v/v) and Florisil as fat retainer allowed an efficient recovery of PCBs (78–112%; RSD: 13–37%), OH-PCBs (46±2%; RSD: 4%) and MeSO2-PCBs (89±21%; RSD: 24%). Comparable results were obtained with an established analysis method for PCBs, OH-PCBs and MeSO2-PCBs. PMID:19019378

On-line pressure measurement using scanning systems

International Nuclear Information System (INIS)

Morss, A.G.; Watson, A.P.

1978-08-01

Data collection methods can be improved significantly by using pressure scanning systems in conjunction with transducers for the measurement of pressure distribution in fluid flow rigs. However, the response of pressure transducers to the slight random pressure fluctuations that occur in practice can cause some measurement problems, especially for accurate work. The nature of these pressure fluctuations is examined and suitable analysis techniques are recommended. Results obtained using these techniques are presented. It is concluded that by using the correct techniques pressure transducer systems can be used to measure pressure distributions accurately and are sufficiently sensitive to measure very small systematic effects with great precision. (author)

Lunar Advanced Volatile Analysis Subsystem: Pressure Transducer Trade Study

Science.gov (United States)

Kang, Edward Shinuk

2017-01-01

In Situ Resource Utilization (ISRU) is a key factor in paving the way for the future of human space exploration. The ability to harvest resources on foreign astronomical objects to produce consumables and propellant offers potential reduction in mission cost and risk. Through previous missions, the existence of water ice at the poles of the moon has been identified, however the feasibility of water extraction for resources remains unanswered. The Resource Prospector (RP) mission is currently in development to provide ground truth, and will enable us to characterize the distribution of water at one of the lunar poles. Regolith & Environment Science and Oxygen & Lunar Volatile Extraction (RESOLVE) is the primary payload on RP that will be used in conjunction with a rover. RESOLVE contains multiple instruments for systematically identifying the presence of water. The main process involves the use of two systems within RESOLVE: the Oxygen Volatile Extraction Node (OVEN) and Lunar Advanced Volatile Analysis (LAVA). Within the LAVA subsystem, there are multiple calculations that depend on accurate pressure readings. One of the most important instances where pressure transducers (PT) are used is for calculating the number of moles in a gas transfer from the OVEN subsystem. As a critical component of the main process, a mixture of custom and commercial off the shelf (COTS) PTs are currently being tested in the expected operating environment to eventually down select an option for integrated testing in the LAVA engineering test unit (ETU).

Research on pressure sensors for biomedical instruments

Science.gov (United States)

Angell, J. B.

1975-01-01

The development of a piezo-resistive pressure transducer is discussed suitable for recording pressures typically encountered in biomedical applications. The pressure transducer consists of a thin silicon diaphragm containing four strain-sensitive resistors, and is fabricated using silicon monolithic integrated-circuit technology. The pressure transducers can be as small as 0.7 mm outer diameter, and are, as a result, suitable for mounting at the tip of a catheter. Pressure-induced stress in the diaphragm is sensed by the resistors, which are interconnected to form a Wheatstone bridge.

Thermal hydraulic analysis of aggressive secondary cooldown in a small break loss of coolant accident with a total loss of high pressure safety injection

International Nuclear Information System (INIS)

Han, Seok Jung; Lim, Ho Gon; Yang, Joon Eon

2003-01-01

To support the development of a Probabilistic Safety Assessment (PSA) model usable in Riskinformed Applications (RIA) for Korea Standard Nuclear power Plants (KSNP), we have performed a thermal hydraulic analysis of Aggressive Secondary Cooldown (ASC) in a 2-inch Small Break Loss Of Coolant Accident (SBLOCA) with a total loss of High Pressure Safety Injection (HPSI). The present study focuses on the estimation of the success criteria of ASC, and the enhanced understanding of the detailed thermal hydraulic behavior and phenomena. The results have shown that the Reactor Coolant System (RCS) pressure can be reduced to the Low Pressure Safety Injection (LPSI) operation conditions without core damage. It was also shown that more relaxed success criteria compared to those in the previous PSA models of KSNP could be used in the new PSA model. However, it was found that the results could be affected by various parameters related with ASC operation, i.e., reference temperature for the calculation of the cooldown rate and its control method

The Effects of Air Pressure on Spontaneous Otoacoustic Emissions of Lizards

NARCIS (Netherlands)

van Dijk, Pim; Manley, Geoffrey A.

Small changes of air pressure outside the eardrum of five lizard species led to changes in frequency, level, and peak width of spontaneous otoacoustic emissions (SOAE). In contrast to humans, these changes generally occurred at very small pressures (<20 mbar). As in humans, SOAE amplitudes were

Automated nondestructive assay system for the measurement of irradiated Rover fuel

International Nuclear Information System (INIS)

Augustson, R.H.; Menlove, H.O.; Smith, D.B.; Bond, A.L.; Durrill, D.C.; Hollowell, W.P.; Bromley, C.P.

1975-01-01

With the termination of the Nuclear Rocket Propulsion (Rover) Program, and associated reactor testing at the Nuclear Rocket Development Station (NRDS), Nevada, plans are progressing to recover the 93 percent enriched uranium contained in irradiated fuel from twenty various test reactors. This fuel is being packaged into 7-cm-dia by 137-cm-long cardboard tubes, using the remote handling facilities (E-MAD Bldg) of NRDS. After packaging, the fuel is shipped to Allied Chemical Corporation, Idaho Falls, Idaho, for uranium recovery. About 4000 tubes will be needed to package and ship the inventory of fuel elements presently at NRDS. This represents a total of approximately 2500 kg of enriched uranium. To complete the accounting records each tube is being nondestructively assayed and records kept on a reactor-by-reactor basis where possible. The assayed values for a reactor are then compared with original input inventory values and discrepancies resolved. The tubes are being assayed by an active neutron interrogation system designed and fabricated by Los Alamos Scientific Laboratory (LASL) and operated by Westinghouse Astronuclear Laboratory (WANL)-Nevada Operations personnel. WANL is the operating contractor in charge of loading and shipping this fuel. (U.S.)

Micro packaged MEMS pressure sensor for intracranial pressure measurement

International Nuclear Information System (INIS)

Liu Xiong; Yao Yan; Ma Jiahao; Zhang Zhaohua; Zhang Yanhang; Wang Qian; Ren Tianling

2015-01-01

This paper presents a micro packaged MEMS pressure sensor for intracranial pressure measurement which belongs to BioMEMS. It can be used in lumbar puncture surgery to measure intracranial pressure. Miniaturization is key for lumbar puncture surgery because the sensor must be small enough to allow it be placed in the reagent chamber of the lumbar puncture needle. The size of the sensor is decided by the size of the sensor chip and package. Our sensor chip is based on silicon piezoresistive effect and the size is 400 × 400 μm 2 . It is much smaller than the reported polymer intracranial pressure sensors such as liquid crystal polymer sensors. In terms of package, the traditional dual in-line package obviously could not match the size need, the minimal size of recently reported MEMS-based intracranial pressure sensors after packaging is 10 × 10 mm 2 . In this work, we are the first to introduce a quad flat no-lead package as the package form of piezoresistive intracranial pressure sensors, the whole size of the sensor is minimized to only 3 × 3 mm 2 . Considering the liquid measurement environment, the sensor is gummed and waterproof performance is tested; the sensitivity of the sensor is 0.9 × 10 −2 mV/kPa. (paper)

A multi-stage-flash desalination plant of relative small performance with an integrated pressurized water reactor as a nuclear heat source

International Nuclear Information System (INIS)

Peltzer, M.; Petersen, G.

1976-01-01

In the Krupp-GKSS joint study MINIPLEX the requirements for seawater-desalination-plants with a performance in the range of 10,000 to 80,000 m 3 /d heated by a nuclear reactor are investigated. The reactor concept is similar to the integrated pressurized water reactor (IPWR) of the nuclear ship OTTO HAHN. The calculated costs of the desalinated water show, that due to the fuel cost advantages of reactors small and medium nuclear desalination plants are economically competetive with oil-fired plants since the steep rise of oil price in autumn 1973. (orig.) [de

Determining best practices in reconnoitering sites for habitability potential on Mars using a semi-autonomous rover: A GeoHeuristic Operational Strategies Test.

Science.gov (United States)

Yingst, R A; Berger, J; Cohen, B A; Hynek, B; Schmidt, M E

2017-03-01

We tested science operations strategies developed for use in remote mobile spacecraft missions, to determine whether reconnoitering a site of potential habitability prior to in-depth study (a walkabout-first strategy) can be a more efficient use of time and resources than the linear approach commonly used by planetary rover missions. Two field teams studied a sedimentary sequence in Utah to assess habitability potential. At each site one team commanded a human "rover" to execute observations and conducted data analysis and made follow-on decisions based solely on those observations. Another team followed the same traverse using traditional terrestrial field methods, and the results of the two teams were compared. Test results indicate that for a mission with goals similar to our field case, the walkabout-first strategy may save time and other mission resources, while improving science return. The approach enabled more informed choices and higher team confidence in choosing where to spend time and other consumable resources. The walkabout strategy may prove most efficient when many close sites must be triaged to a smaller subset for detailed study or sampling. This situation would arise when mission goals include finding, identifying, characterizing or sampling a specific material, feature or type of environment within a certain area.

Mineralogical Results from the Mars Science Laboratory Rover Curiosity

Science.gov (United States)

Blake, David Frederick.

2017-01-01

NASA's CheMin instrument, the first X-ray Diffractometer flown in space, has been operating on Mars for nearly five years. CheMin was first to establish the quantitative mineralogy of the Mars global soil (1). The instrument was next used to determine the mineralogy of a 3.7 billion year old lacustrine mudstone, a result that, together with findings from other instruments on the MSL Curiosity rover, documented the first habitable environment found on another planet (2). The mineralogy of this mudstone from an ancient playa lake was also used to derive the maximum concentration of CO2 in the early Mars atmosphere, a surprisingly low value that calls into question the current theory that CO2 greenhouse warming was responsible for the warm and wet environment of early Mars. CheMin later identified the mineral tridymite, indicative of silica-rich volcanism, in mudstones of the Murray formation on Mt. Sharp. This discovery challenges the paradigm of Mars as a basaltic planet and ushers in a new chapter of comparative terrestrial planetology (3). CheMin is now being used to systematically sample the sedimentary layers that comprise the lower strata of Mt. Sharp, a 5,000 meter sequence of sedimentary rock laid down in what was once a crater lake, characterizing isochemical sediments that through their changing mineralogy, document the oxidation and drying out of the Mars in early Hesperian time.

An on-line pressurizer surveillance system design to prevent small-break loss-of-coolant accidents through power-operated relief valves using a microcomputer

International Nuclear Information System (INIS)

Lee, J.H.; Chang, S.H.

1987-01-01

A small-break loss-of-coolant accident (LOCA) caused by a stuck-open power-operated relief valve is one of the important contributors to nuclear power plant risk. A pressurizer surveillance system was designed to use a microcomputer to prevent the malfunction of the system; the effect of this improvement has been assessed through probabilistic risk assessment. The microcomputer diagnoses the malfunction of the system by a process-checking method and automatically performs the backup action related to each malfunction. This improvement means that we can correctly diagnose ''spurious opening,'' ''failure to reclose,'' and ''small-break LOCA,'' which are difficult for operators to diagnose quickly and correctly, and by taking automatic backup action one can reduce the probability of human error

Meta-analysis of timolol on diurnal and nighttime intraocular pressure and blood pressure.

LENUS (Irish Health Repository)

Lee, Princeton Wen-Yuan

2012-02-01

PURPOSE: To evaluate the nighttime intraocular pressure (IOP) and blood pressure (BP) response to timolol treatment in patients with ocular hypertension or primary open-angle glaucoma. METHODS: This was a meta-analysis of previously published studies that must have been randomized, prospective, crossover or parallel, single or double-masked trials. The treatment period must have been >\\/=2 weeks with >\\/=19 patients per treatment arm for a crossover, and >\\/=50 patients for a parallel designed trial. Studies must have included both baseline and treated 24-hour curves. RESULTS: For the IOP analysis, we included 8 articles with 340 patients. A reduction from baseline was observed for timolol at each time point and for the 24-hour curve (p<\\/=0.009). When 2 studies, in which timolol was used adjunctively, were removed, a similar difference was observed as above at each time point and for the 24-hour curve (p<\\/=0.003). In 2 studies, there were small reductions from baseline for the mean diastolic and systolic BPs at most time points and for the 24-hour curve (3.9 and 4.2 mmHg, respectively) with timolol treatment. The ocular perfusion pressure did not show any difference between baseline and timolol treatment at any time point or for the 24-hour curve (p>0.05). CONCLUSIONS: This meta-analysis suggests that topical timolol therapy provides an ocular hypotensive effect over the 24-hour curve, including the nighttime hours, and while small reductions in the systolic and diastolic pressures occur, the ocular perfusion pressure is not altered over 24 hours.

Nanocomposite-Based Microstructured Piezoresistive Pressure Sensors for Low-Pressure Measurement Range

Directory of Open Access Journals (Sweden)

Vasileios Mitrakos

2018-01-01

Full Text Available Piezoresistive pressure sensors capable of detecting ranges of low compressive stresses have been successfully fabricated and characterised. The 5.5 × 5 × 1.6 mm3 sensors consist of a planar aluminium top electrode and a microstructured bottom electrode containing a two-by-two array of truncated pyramids with a piezoresistive composite layer sandwiched in-between. The responses of two different piezocomposite materials, a Multiwalled Carbon Nanotube (MWCNT-elastomer composite and a Quantum Tunneling Composite (QTC, have been characterised as a function of applied pressure and effective contact area. The MWCNT piezoresistive composite-based sensor was able to detect pressures as low as 200 kPa. The QTC-based sensor was capable of detecting pressures as low as 50 kPa depending on the contact area of the bottom electrode. Such sensors could find useful applications requiring the detection of small compressive loads such as those encountered in haptic sensing or robotics.

Measurement of small values of hydrostatic pressure difference / Pomiar małych wartości różnicy ciśnień hydrostatycznych

Science.gov (United States)

Broda, Krzysztof; Filipek, Wiktor

2012-10-01

In order to describe the fluid flow through the porous centre, made of identical spheres, it is necessary to know the pressure, but in fact - the pressure distribution. For the flows in the range that was traditionally called laminar flow (i. e. for Reynolds numbers (Bear, 1988; Duckworth, 1983; Troskolański, 1957) from the range 0,01 to 3) it is virtually impossible with the use of the tools directly available on the market. Therefore, many scientists who explore this problem have concentrated only on the research of the velocity distribution of the medium that penetrates the intended centre (Bear, 1988) or pressure distribution at high hydraulic gradients (Trzaska & Broda, 1991, 2000; Trzaska et al., 2005). It may result from the inaccessibility to the measurement methods that provide measurement of very low hydrostatic pressures, such as pressure resulting from the weight of liquid located in the gravitational field (Duckworth, 1983; Troskolański, 1957). The pressure value c. 10 Pa (Troskolański, 1957) can be generated even by 1 mm height difference between the two levels of the free water surface, which in fact constitutes the definition of gauging tools of today measuring the level of the hydrostatic pressure. Authors proposed a method of hydrostatic pressure measurement and devised a gauging tool. Then a series of tests was conducted aiming at establishing what is the influence of various factors, such as temperature, atmospheric pressure, velocity of measurement completion, etc. on the accuracy and method of measurements. A method for considerable reduction of hysteresis that occurs during measurement was also devised. The method of measurement of small hydrostatic difference measurements allows for the accuracy of measurement of up to 0.5 Pa. Measurement results can be improved successfully by one order of magnitude, which for sure would entail necessary temperature stabilization of the tool. It will be more difficult though to compensate the influence

Lunar polar rover science operations: Lessons learned and mission architecture implications derived from the Mojave Volatiles Prospector (MVP) terrestrial field campaign

Science.gov (United States)

Heldmann, Jennifer L.; Colaprete, Anthony; Elphic, Richard C.; Lim, Darlene; Deans, Matthew; Cook, Amanda; Roush, Ted; Skok, J. R.; Button, Nicole E.; Karunatillake, S.; Stoker, Carol; Marquez, Jessica J.; Shirley, Mark; Kobayashi, Linda; Lees, David; Bresina, John; Hunt, Rusty

2016-08-01

The Mojave Volatiles Prospector (MVP) project is a science-driven field program with the goal of producing critical knowledge for conducting robotic exploration of the Moon. Specifically, MVP focuses on studying a lunar mission analog to characterize the form and distribution of lunar volatiles. Although lunar volatiles are known to be present near the poles of the Moon, the three dimensional distribution and physical characteristics of lunar polar volatiles are largely unknown. A landed mission with the ability to traverse the lunar surface is thus required to characterize the spatial distribution of lunar polar volatiles. NASA's Resource Prospector (RP) mission is a lunar polar rover mission that will operate primarily in sunlit regions near a lunar pole with near-real time operations to characterize the vertical and horizontal distribution of volatiles. The MVP project was conducted as a field campaign relevant to the RP lunar mission to provide science, payload, and operational lessons learned to the development of a real-time, short-duration lunar polar volatiles prospecting mission. To achieve these goals, the MVP project conducted a simulated lunar rover mission to investigate the composition and distribution of surface and subsurface volatiles in a natural environment with an unknown volatile distribution within the Mojave Desert, improving our understanding of how to find, characterize, and access volatiles on the Moon.

Compressed-tube pressure cell for optical studies at ocean pressures: Application to glucose mutarotation kinetics.

Science.gov (United States)

Lamelas, F J

2016-12-01

A self-contained compressed-tube pressure cell is tested to 25 MPa. The cell is very simple to construct and offers stable pressure control with optical access to fluid samples. The physical path length of light through the cell is large enough to measure optical activity. The entire system is relatively small and portable, and it is vibration-free, since a compressor is not used. Operation of the cell is demonstrated by measuring the mutarotation rate of aqueous glucose solutions at 25 °C. A logarithmic plot of the rate constant vs. pressure yields an activation volume for mutarotation of -22 cm 3 /mol, approximately twice the value measured previously at higher pressures.

Tribology aspects of a pressure vessel closure subjected to pressure cycling

International Nuclear Information System (INIS)

George, A.F.; Williams, M.E.

1988-04-01

A repair method being considered for a steel pressure vessel is to cut away the faulty part leaving an unreinforced circular hole in the curved wall and cover it with a sealed plate placed inside. In order to investigate the structural properties of such a repair a large model vessel (6m by 2m) was tested under pressure (about 2.5 MPa) and pressure cycling. This cycling caused relative movements at the loaded interface between the lid and the vessel. A tribological examination of the rubbing surfaces was carried out. The tribological examination is described and a small supporting programme of laboratory scaling tests. It gives the results and attempts to interpret them with particular attention given to wear, fretting fatigue and scaling to plant conditions. (author)

The steam pressure effect on high temperature corrosion of zircaloy-4

International Nuclear Information System (INIS)

Kim, K. P.; Park, G. H.

1998-01-01

To find the effect of pressure on the high temperature oxidation of zircaloy-4, an autoclave capable of measuring the degree of oxidation at high temperatures and high pressure was manufactured. The degree of high temperature oxidation of zircaloy-4 was measured at three different conditions, high pressure steam, high pressure Ar gas with small amount of steam, and 1 atm steam. All the measurements were done at 750 deg C. The oxide thickness is much thicker in high pressure steam, comparing to that in the 1 atm steam. And, the higher is the steam pressure, the thicker becomes the oxide. No effect was observed in the case of high pressure Ar containing small amount of steam. Many cracks exist on the surface of specimens oxidized at high pressure steam, which come from the enhanced tetragonal to monoclinic phase transformation due to high pressure steam. The enhanced oxidation seems to oxide cracking

Experimental study of the pressure characteristics in the Stirling refrigerator

International Nuclear Information System (INIS)

Hong, Yong Ju; Park, Seong Je; Kim, Hyo Bong; Koh, Deuk Yong

2001-01-01

The linear compressor have been widely used for pressure wave generation in the Stirling cryocooler and Stirling type pulse tube cryocooler for tactical purpose. The linear compressor has small and compact structure, and long life due to having non-contact sealing mechanism and the pressure drop through regenerator was ver important role in the motion of displacer in the expander of the Stirling cryocooler. In this study, the characteristic of the linear compressor and the pressure drop through regenerator in the expander was experimentally investigated. The results show resonance of the compressor is very important to get maximum performance and the gas spring force in the compression space of the compressor has effect on the characteristic of resonance and the results show the pressure drop through regenerator is very small than operating pressure change

Mini-PROven. Reduced emissions from small and medium-size coke ovens thanks to single-chamber pressure control; Mini-PROven. Emissionsreduzierung an kleinen und mittleren Koksoefen mit einer Einzelkammerdruckregelung

Energy Technology Data Exchange (ETDEWEB)

Huhn, Friedrich; Krebber, Frank; Kuehn-Gajdzik, Joanna; Ueberschaer, Kerstin [ThyssenKrupp Uhde GmbH, Dortmund (Germany). Coke Plant Technologies Div.

2012-07-01

For environment and occupational health reasons it is becoming increasingly important for coke plants to be operated with the lowest possible level of emissions. In the past, changing pressure conditions in each individual oven, with particularly high values at the beginning of the coking period, often resulted in considerable emissions at the oven closures. To prevent this happening on modern large-scale ovens, ThyssenKrupp Uhde developed the PROven trademark (Pressure Regulated Oven), a single-chamber pressure control system which regulates the pressure in the individual coke chambers down to a constantly low level. In the meantime, after many years of successful service, the system has been upgraded in both its design and process engineering. The result is Mini-PROven, which in future can also be retro-fitted to old small and medium-size coke oven batteries in the interest of better environmental protection. (orig.)

Pressurized waterproof case electronic device

KAUST Repository

Berumen, Michael L.

2013-01-31

A pressurized waterproof case for an electronic device is particularly adapted for fluid-tight containment and operation of a touch-screen electronic device or the like therein at some appreciable water depth. In one example, the case may be formed as an enclosure having an open top panel or face covered by a flexible, transparent membrane or the like for the operation of the touchscreen device within the case. A pressurizing system is provided for the case to pressurize the case and the electronic device therein to slightly greater than ambient in order to prevent the external water pressure from bearing against the transparent membrane and pressing it against the touch screen, thereby precluding operation of the touch screen device within the case. The pressurizing system may include a small gas cartridge or may be provided from an external source.

Ultrahigh Sensitivity Piezoresistive Pressure Sensors for Detection of Tiny Pressure.

Science.gov (United States)

Li, Hongwei; Wu, Kunjie; Xu, Zeyang; Wang, Zhongwu; Meng, Yancheng; Li, Liqiang

2018-05-31

High sensitivity pressure sensors are crucial for the ultra-sensitive touch technology and E-skin, especially at the tiny pressure range below 100 Pa. However, it is highly challenging to substantially promote sensitivity beyond the current level at several to two hundred kPa -1 , and to improve the detection limit lower than 0.1 Pa, which is significant for the development of pressure sensors toward ultrasensitive and highly precise detection. Here, we develop an efficient strategy to greatly improve the sensitivity near to 2000 kPa -1 by using short channel coplanar device structure and sharp microstructure, which is systematically proposed for the first time and rationalized by the mathematic calculation and analysis. Significantly, benefiting from the ultrahigh sensitivity, the detection limit is improved to be as small as 0.075 Pa. The sensitivity and detection limit are both superior to the current levels, and far surpass the function of human skin. Furthermore, the sensor shows fast response time (50 μs), excellent reproducibility and stability, and low power consumption. Remarkably, the sensor shows excellent detection capacity in the tiny pressure range including LED switching with a pressure of 7 Pa, ringtone (2-20 Pa) recognition, and ultrasensitive (0.1 Pa) electronic glove. This work represents a performance and strategic progress in the field of pressure sensing.

Nuclear reactor of pressurized liquid coolant type

International Nuclear Information System (INIS)

Costes, D.

1976-01-01

The reactor comprises a vertical concrete pressure vessel, a bell-housing having an open lower end and disposed coaxially with the interior of the pressure vessel so as to delimit therewith a space filled with gas under pressure for the thermal insulation of the internal vessel wall, a pressurizing device for putting the coolant under pressure within the bell-housing and comprising a volume of control gas in contact with a large free surface of coolant in order that an appreciable variation in volume of liquid displaced within the coolant circuit inside the bell-housing should correspond to a small variation in pressure of the control gas. 9 claims, 3 drawing figures

On Small Disturbance Ascent Vent Behavior

Science.gov (United States)

Woronowicz, Michael

2015-01-01

As a spacecraft undergoes ascent in a launch vehicle, its ambient pressure environment transitions from one atmosphere to high vacuum in a matter of a few minutes. Venting of internal cavities is necessary to prevent the buildup of pressure differentials across cavity walls. These pressure differentials are often restricted to low levels to prevent violation of container integrity. Such vents usually consist of fixed orifices, ducts, or combinations of both. Duct conductance behavior is fundamentally different from that for orifices in pressure driven flows governing the launch vehicle ascent depressurization environment. Duct conductance is governed by the average pressure across its length, while orifice conductance is dictated by a pressure ratio. Hence, one cannot define a valid equivalent orifice for a given duct across a range of pressure levels. This presentation discusses development of expressions for these two types of vent elements in the limit of small pressure differentials, explores conditions for their validity, and compares their features regarding ascent depressurization performance.

Pressure exerted by a vesicle on a surface

International Nuclear Information System (INIS)

Owczarek, A L; Prellberg, T

2014-01-01

Several recent works have considered the pressure exerted on a wall by a model polymer. We extend this consideration to vesicles attached to a wall, and hence include osmotic pressure. We do this by considering a two-dimensional directed model, namely that of area-weighted Dyck paths. Not surprisingly, the pressure exerted by the vesicle on the wall depends on the osmotic pressure inside, especially its sign. Here, we discuss the scaling of this pressure in the different regimes, paying particular attention to the crossover between positive and negative osmotic pressure. In our directed model, there exists an underlying Airy function scaling form, from which we extract the dependence of the bulk pressure on small osmotic pressures. (paper)

Small School Reform

Directory of Open Access Journals (Sweden)

Carroll E. Bronson

2013-05-01

Full Text Available This qualitative ethnographic case study explored the evolution of a public urban high school in its 3rd year of small school reform. The study focused on how the high school proceeded from its initial concept, moving to a small school program, and emerging as a new small high school. Data collection included interviews, observations, and document review to develop a case study of one small high school sharing a multiplex building. The first key finding, “Too Many Pieces, Not Enough Glue,” revealed that the school had too many new programs starting at once and they lacked a clear understanding of their concept and vision for their new small school, training on the Montessori philosophies, teaching and learning in small schools, and how to operate within a teacher-cooperative model. The second key finding, “A Continuous Struggle,” revealed that the shared building space presented problems for teachers and students. District policies remain unchanged, resulting in staff and students resorting to activist approaches to get things done. These findings offer small school reform leaders suggestions for developing and sustaining a small school culture and cohesion despite the pressures to revert back to top-down, comprehensive high school norms.

Holographic and acoustic emission evaluation of pressure vessels

International Nuclear Information System (INIS)

Boyd, D.M.

1980-01-01

Optical holographic interfereometry and acoustic emission monitoring were simultaneously used to evaluate two small, high pressure vessels during pressurization. The techniques provide pressure vessel designers with both quantitative information such as displacement/strain measurements and qualitative information such as flaw detection. The data from the holographic interferograms were analyzed for strain profiles. The acoustic emission signals were monitored for crack growth and vessel quality

Layers of 'Cabo Frio' in 'Victoria Crater'

Science.gov (United States)

2006-01-01

This view of 'Victoria crater' is looking southeast from 'Duck Bay' towards the dramatic promontory called 'Cabo Frio.' The small crater in the right foreground, informally known as 'Sputnik,' is about 20 meters (about 65 feet) away from the rover, the tip of the spectacular, layered, Cabo Frio promontory itself is about 200 meters (about 650 feet) away from the rover, and the exposed rock layers are about 15 meters (about 50 feet) tall. This is an approximately true color rendering of images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.

Layers of 'Cabo Frio' in 'Victoria Crater' (False Color)

Science.gov (United States)

2006-01-01

This view of 'Victoria crater' is looking southeast from 'Duck Bay' towards the dramatic promontory called 'Cabo Frio.' The small crater in the right foreground, informally known as 'Sputnik,' is about 20 meters (about 65 feet) away from the rover, the tip of the spectacular, layered, Cabo Frio promontory itself is about 200 meters (about 650 feet) away from the rover, and the exposed rock layers are about 15 meters (about 50 feet) tall. This is an enhanced false color rendering of images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.

Layers of 'Cabo Frio' in 'Victoria Crater' (Stereo)

Science.gov (United States)

2006-01-01

This view of 'Victoria crater' is looking southeast from 'Duck Bay' towards the dramatic promontory called 'Cabo Frio.' The small crater in the right foreground, informally known as 'Sputnik,' is about 20 meters (about 65 feet) away from the rover, the tip of the spectacular, layered, Cabo Frio promontory itself is about 200 meters (about 650 feet) away from the rover, and the exposed rock layers are about 15 meters (about 50 feet) tall. This is a red-blue stereo anaglyph generated from images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 430-nanometer filters.

Pressure vessels and methods of sealing leaky tubes disposed in pressure vessels

International Nuclear Information System (INIS)

Larson, G.C.

1980-01-01

This invention relates to pressure vessels and to methods of sealing leaky tubes in them and is especially applicable to pressure vessels in the form of sheet-and-tube type heat exchangers constructed with a large number of relatively small diameter tubes grouped in a bundle. To seal off a leaky tube in such a heat exchanger an explosive activated plug in the form of a hollow metal body is used, inserted at each end of the tube to be sealed. Using the arrangement of pressure vessel and associated tube sheets and the explosive activated plug method of sealing a leaky tube as described in this invention it is claimed that distortion of the adjacent tubes and the tube sheets is reduced when the explosive activated plugs are detonated. (U.K.)

Multi-stage-flash desalination plants of relative small performance with integrated pressurized water reactors as a nuclear heat source

International Nuclear Information System (INIS)

Petersen, G.; Peltzer, M.

1977-01-01

In the Krupp-GKSS joint study MINIPLEX the requirements for seawater-desalination plants with a performance in the range of 10 000 to 80 000 m 3 distillate per day heated by a nuclear reactor are investigated. The reactor concept is similar to the Integrated Pressurized Water Reactor (IPWR) of the nuclear ship OTTO HAHN. The design study shows that IPWR systems have specific advantages up to 200 MWth compared to other reactor types at least being adapted for single- and dual-purpose desalination plants. The calculated costs of the desalinated water show that due to fuel cost advantages of reactors small and medium nuclear desalination plants are economically competetive with oil-fired plants since the steep rise of oil price in autumn 1973. (author)

Feasibility of generating a useful laser-induced breakdown spectroscopy plasma on rocks at high pressure: preliminary study for a Venus mission

International Nuclear Information System (INIS)

Arp, Zane A.; Cremers, David A.; Harris, Ronny D.; Oschwald, David M.; Parker, Gary R.; Wayne, David M.

2004-01-01

Laser-induced breakdown spectroscopy (LIBS) is being developed for future use on landers and rovers to Mars. The method also has potential for use on probes to other planets, the Moon, asteroids and comets. Like Mars, Venus is of strong interest because of its proximity to earth, but unlike Mars, conditions at the surface are far more hostile with temperatures in excess of 700 K and pressures on the order of 9.1 MPa (90 atm). These conditions present a significant challenge to spacecraft design and demand that rapid methods of chemical data gathering be implemented. The advantages of LIBS (e.g. stand-off and very rapid analysis) make the method particularly attractive for Venus exploration because of the expected short operational lifetimes (∼2 h) of surface instrumentation. Although the high temperature of Venus should pose no problem to the analytical capabilities of the LIBS spark, the demonstrated strong dependence of laser plasma characteristics on ambient gas pressures below earth atmospheric pressure requires that LIBS measurements be evaluated at the high Venus surface pressures. Here, we present a preliminary investigation of LIBS at 9.1 MPa for application to the analysis of a basalt rock sample. The results suggest the feasibility of the method for a Venus surface probe and that further study is justified

Feasibility of generating a useful laser-induced breakdown spectroscopy plasma on rocks at high pressure: preliminary study for a Venus mission

Energy Technology Data Exchange (ETDEWEB)

Arp, Zane A.; Cremers, David A. E-mail: cremers_david@lanl.gov; Harris, Ronny D.; Oschwald, David M.; Parker, Gary R.; Wayne, David M

2004-07-30

Laser-induced breakdown spectroscopy (LIBS) is being developed for future use on landers and rovers to Mars. The method also has potential for use on probes to other planets, the Moon, asteroids and comets. Like Mars, Venus is of strong interest because of its proximity to earth, but unlike Mars, conditions at the surface are far more hostile with temperatures in excess of 700 K and pressures on the order of 9.1 MPa (90 atm). These conditions present a significant challenge to spacecraft design and demand that rapid methods of chemical data gathering be implemented. The advantages of LIBS (e.g. stand-off and very rapid analysis) make the method particularly attractive for Venus exploration because of the expected short operational lifetimes ({approx}2 h) of surface instrumentation. Although the high temperature of Venus should pose no problem to the analytical capabilities of the LIBS spark, the demonstrated strong dependence of laser plasma characteristics on ambient gas pressures below earth atmospheric pressure requires that LIBS measurements be evaluated at the high Venus surface pressures. Here, we present a preliminary investigation of LIBS at 9.1 MPa for application to the analysis of a basalt rock sample. The results suggest the feasibility of the method for a Venus surface probe and that further study is justified.

Inter- and intra-observer reliability of masking in plantar pressure measurement analysis.

Science.gov (United States)

Deschamps, K; Birch, I; Mc Innes, J; Desloovere, K; Matricali, G A

2009-10-01

Plantar pressure measurement is an important tool in gait analysis. Manual placement of small masks (masking) is increasingly used to calculate plantar pressure characteristics. Little is known concerning the reliability of manual masking. The aim of this study was to determine the reliability of masking on 2D plantar pressure footprints, in a population with forefoot deformity (i.e. hallux valgus). Using a random repeated-measure design, four observers identified the third metatarsal head on a peak-pressure barefoot footprint, using a small mask. Subsequently, the location of all five metatarsal heads was identified, using the same size of masks and the same protocol. The 2D positional variation of the masks and the peak pressure (PP) and pressure time integral (PTI) values of each mask were calculated. For single-masking the lowest inter-observer reliability was found for the distal-proximal direction, causing a clear, adverse impact on the reliability of the pressure characteristics (PP and PTI). In the medial-lateral direction the inter-observer reliability could be scored as high. Intra-observer reliability was better and could be scored as high or good for both directions, with a correlated improved reliability of the pressure characteristics. Reliability of multi-masking showed a similar pattern, but overall values tended to be lower. Therefore, small sized masking in order to define pressure characteristics in the forefoot should be done with care.

Genetic variants in novel pathways influence blood pressure and cardiovascular disease risk

NARCIS (Netherlands)

G.B. Ehret (Georg); P. Munroe (Patricia); K.M. Rice (Kenneth); M. Bochud (Murielle); A.D. Johnson (Andrew); D.I. Chasman (Daniel); A.V. Smith (Albert Vernon); M.D. Tobin (Martin); G.C. Verwoert (Germaine); S.J. Hwang; V. Pihur (Vasyl); P. Vollenweider (Peter); P.F. O'Reilly (Paul); N. Amin (Najaf); J.L. Bragg-Gresham (Jennifer L.); A. Teumer (Alexander); N.L. Glazer (Nicole); L.J. Launer (Lenore); J.H. Zhao (Jing Hua); Y.S. Aulchenko (Yurii); S.C. Heath (Simon); S. Sõber (Siim); A. Parsa (Afshin); J. Luan; P. Arora (Pankaj); A. Dehghan (Abbas); F. Zhang (Feng); G. Lucas (Gavin); A.A. Hicks (Andrew); A.U. Jackson (Anne); J. Peden (John); T. Tanaka (Toshiko); S.H. Wild (Sarah); I. Rudan (Igor); W. Igl (Wilmar); Y. Milaneschi (Yuri); A.N. Parker (Alex); C. Fava (Cristiano); J.C. Chambers (John); E.R. Fox (Ervin); M. Kumari (Meena); M. Jin Go (Min); P. van der Harst (Pim); W. Hong Linda Kao (Wen); M. Sjögren (Marketa); D.G. Vinay; M. Alexander (Myriam); Y. Tabara (Yasuharu); S. Shaw-Hawkins (Sue); P.H. Whincup (Peter); Y. Liu (YongMei); G. Shi (Gang); J. Kuusisto (Johanna); B. Tayo (Bamidele); M. Seielstad (Mark); X. Sim (Xueling); K.-D. Hoang Nguyen; T. Lehtimäki (Terho); G. Matullo (Giuseppe); Y. Wu (Ying); T.R. Gaunt (Tom); N. Charlotte Onland-Moret; M.N. Cooper (Matthew); C. Platou (Carl); E. Org (Elin); R. Hardy (Rebecca); S. Dahgam (Santosh); J. Palmen (Jutta); V. Vitart (Veronique); P.S. Braund (Peter); T. Kuznetsova (Tatiana); C.S.P.M. Uiterwaal (Cuno); A. Adeyemo (Adebowale); W. Palmas (Walter); H. Campbell (Harry); B. Ludwig (Barbara); M. Tomaszewski; I. Tzoulaki; N.D. Palmer (Nicholette); T. Aspelund (Thor); M. Garcia (Melissa); Y.-P.C. Chang (Yen-Pei); J.R. O´Connell; N.I. Steinle (Nanette); D.E. Grobbee (Diederick); D.E. Arking (Dan); S.L. Kardia (Sharon); A.C. Morrison (Alanna); D.G. Hernandez (Dena); S.S. Najjar (Samer); W.L. McArdle (Wendy); D. Hadley (David); M.J. Brown (Morris); J. Connell (John); A. Hingorani (Aroon); I.N.M. Day (Ian); D.A. Lawlor (Debbie); J.P. Beilby (John); R.W. Lawrence (Robert); R. Clarke; J. Hopewell; H. Ongen (Halit); A.W. Dreisbach (Albert); Y. Li (Yali); J. Hunter Young; J.C. Bis (Joshua); M. Kähönen (Mika); J. Viikari (Jorma); N.R. Lee (Nanette); M-H. Chen (Ming-Huei); M. Olden (Matthias); C. Pattaro (Cristian); J.A. Hoffman Bolton (Judith); A. Köttgen (Anna); S.M. Bergmann (Sven); V. Mooser (Vincent); N. Chaturvedi (Nish); T.M. Frayling (Timothy); M. Islam (Muhammad); T.H. Jafar (Tazeen); S.R. Kulkarni (Smita); S.R. Bornstein (Stefan); J. Gräßler (Jürgen); L. Groop (Leif); B.F. Voight (Benjamin); J. Kettunen (Johannes); P. Howard (Philip); A. Taylor (Andrew); S. Guarrera (Simonetta); F. Ricceri (Fulvio); V. Emilsson (Valur); A.S. Plump (Andrew); K-T. Khaw (Kay-Tee); A.B. Weder (Alan); S.C. Hunt (Steven); Y.V. Sun (Yan); R.N. Bergman (Richard); F.S. Collins (Francis); L.L. Bonnycastle (Lori); L.J. Scott (Laura); H.M. Stringham (Heather); L. Peltonen (Leena Johanna); M. Perola (Markus); E. Vartiainen (Erkki); S.-M. Brand; J.A. Staessen (Jan); Y.A. Wang (Ying); P.R. Burton (Paul); M. Soler Artigas (Maria); Y. Dong (Yanbin); H. Snieder (Harold); H. Zhu (Haidong); K. Lohman (Kurt); M.E. Rudock (Megan); S.R. Heckbert (Susan); K.L. Wiggins (Kerri); A. Doumatey (Ayo); D. Shriner (Daniel); G. Veldre (Gudrun); M. Viigimaa (Margus); S. Kinra (Sanjay); D. Prabhakaran (Dorairaj); V. Tripathy (Vikal); C.D. Langefeld (Carl); A. Rosengren (Annika); D.S. Thelle (Dag); A. Maria Corsi (Anna); A. Singleton (Andrew); T. Forrester (Terrence); G. Hilton (Gina); C.A. McKenzie (Colin); T. Salako (Tunde); N. Iwai (Naoharu); Y. Kita (Yoshikuni); T. Ogihara (Toshio); T. Ohkubo (Takayoshi); T. Okamura (Tomonori); H. Ueshima (Hirotsugu); S. Umemura (Satoshi); S. Eyheramendy (Susana); T. Meitinger (Thomas); H.E. Wichmann (Heinz Erich); Y. Shin Cho (Yoon); H.-L. Kim; J.S. Sehmi (Joban); B. Hedblad (Bo); P. Nilsson (Peter); G. Davey-Smith (George); A. Wong (Andrew); N. Narisu (Narisu); A. Stancáková (Alena); L.J. Raffel (Leslie); J. Yao (Jie); S. Kathiresan (Sekar); C.J. O'Donnell (Christopher); S.M. Schwartz (Stephen); M.A. Ikram (Arfan); W.T. Longstreth Jr; T.H. Mosley (Thomas); S. Seshadri (Sudha); N.R.G. Shrine (Nick); L.V. Wain (Louise); M.A. Morken (Mario); A.J. Swift (Amy); J. Laitinen (Jaana); I. Prokopenko (Inga); P. Zitting (Paavo); S.E. Humphries (Steve); J. Danesh (John); A. Rasheed (Asif); A. Goel (Anuj); A. Hamsten (Anders); H. Watkins (Hugh); W.H. van Gilst (Wiek); C.S. Janipalli (Charles); K. Radha Mani; C. Yajnik (Chittaranjan); A. Hofman (Albert); F.U.S. Mattace Raso (Francesco); B.A. Oostra (Ben); A. Demirkan (Ayşe); A.J. Isaacs (Aaron); F. Rivadeneira Ramirez (Fernando); E. Lakatta (Edward); M. Orrù (Marco); A. Scuteri (Angelo); M. Ala-Korpela (Mika); A.J. Kangas (Antti); L.-P. Lyytikäinen (Leo-Pekka); P. Soininen (Pasi); T. Tukiainen (Taru); P. Würtz (Peter); R. Twee-Hee Ong (Rick); M. Dörr (Marcus); H.K. Kroemer (Heyo); U. Völker (Uwe); H. Völzke (Henry); P. Galan (Pilar); S. Hercberg (Serge); G.M. Lathrop (Mark); D. Zelenika (Diana); P. Deloukas (Panagiotis); M. Mangino (Massimo); T.D. Spector (Timothy); G. Zhai (Guangju); J.F. Meschia (James F.); M.A. Nalls (Michael); P. Sharma (Pankaj); J. Terzic (Janos); M.V. Kranthi Kumar; M. Denniff (Matthew); E. Zukowska-Szczechowska (Ewa); L.E. Wagenknecht (Lynne); F. Gerald R. Fowkes; F.J. Charchar (Fadi); P.E.H. Schwarz (Peter); C. Hayward (Caroline); X. Guo (Xiuqing); C. Rotimi (Charles); M.L. Bots (Michiel); N.J. Samani (Nilesh); O. Polasek (Ozren); P.J. Talmud (Philippa); F. Nyberg (Fredrik); D. Kuh (Diana); M. Laan (Maris); K. Hveem (Kristian); Y.T. van der Schouw (Yvonne); J.P. Casas (Juan); K.L. Mohlke (Karen); P. Vineis (Paolo); O. Raitakari (Olli); S.K. Ganesh (Santhi); E. Shyong Tai; M. Laakso (Markku); D.C. Rao (Dabeeru C.); T.B. Harris (Tamara); R.W. Morris (Richard); A. Dominiczak (Anna); M. Kivimaki (Mika); M. Marmot (Michael); T. Miki (Tetsuro); D. Saleheen; G.R. Chandak (Giriraj); J. Coresh (Josef); G. Navis (Gerjan); V. Salomaa (Veikko); B.-G. Han; J.S. Kooner (Jaspal); O. Melander (Olle); P.M. Ridker (Paul); S. Bandinelli (Stefania); U. Gyllensten (Ulf); A.F. Wright (Alan); J.F. Wilson (James); L. Ferrucci (Luigi); M. Farrall (Martin); J. Tuomilehto (Jaakko); P.P. Pramstaller (Peter Paul); R. Elosua (Roberto); N. Soranzo (Nicole); E.J.G. Sijbrands (Eric); D. Altshuler (David); R.J.F. Loos (Ruth); A.R. Shuldiner (Alan); C. Gieger (Christian); P. Meneton (Pierre); A.G. Uitterlinden (André); N.J. Wareham (Nick); V. Gudnason (Vilmundur); J.I. Rotter (Jerome); R. Rettig (Rainer); M. Uda (Manuela); D.P. Strachan (David); J.C.M. Witteman (Jacqueline); A.L. Hartikainen; J.S. Beckmann (Jacques); E.A. Boerwinkle (Eric); J. Erdmann (Jeanette); R.S. Vasan (Ramachandran Srini); M. Boehnke (Michael); M.G. Larson (Martin); M.R. Järvelin; B.M. Psaty (Bruce); P. Tikka-Kleemola (Päivi); C. Newton-Cheh (Christopher); P. Elliott (Paul); D. Levy (Daniel); M. Caulfield (Mark); G.R. Abecasis (Gonçalo); L.S. Adair (Linda); S.J.L. Bakker (Stephan); I.E. Barroso (Inês)

2011-01-01

textabstractBlood pressure is a heritable trait influenced by several biological pathways and responsive to environmental stimuli. Over one billion people worldwide have hypertension (≥140mmg Hg systolic blood pressure ≥90mmg Hg diastolic blood pressure). Even small increments in blood pressure are

Magnetically Attached Multifunction Maintenance Rover

Science.gov (United States)

Bar-Cohen, Yoseph; Joffe, Benjamin

2005-01-01

A versatile mobile telerobot, denoted the magnetically attached multifunction maintenance rover (MAGMER), has been proposed for use in the inspection and maintenance of the surfaces of ships, tanks containing petrochemicals, and other large ferromagnetic structures. As its name suggests, this robot would utilize magnetic attraction to adhere to a structure. As it moved along the surface of the structure, the MAGMER would perform tasks that could include close-up visual inspection by use of video cameras, various sensors, and/or removal of paint by water-jet blasting, laser heating, or induction heating. The water-jet nozzles would be mounted coaxially within compressed-air-powered venturi nozzles that would collect the paint debris dislodged by the jets. The MAGMER would be deployed, powered, and controlled from a truck, to which it would be connected by hoses for water, compressed air, and collection of debris and by cables for electric power and communication (see Figure 1). The operation of the MAGMER on a typical large structure would necessitate the use of long cables and hoses, which can be heavy. To reduce the load of the hoses and cables on the MAGMER and thereby ensure its ability to adhere to vertical and overhanging surfaces, the hoses and cables would be paid out through telescopic booms that would be parts of a MAGMER support system. The MAGMER would move by use of four motorized, steerable wheels, each of which would be mounted in an assembly that would include permanent magnets and four pole pieces (see Figure 2). The wheels would protrude from between the pole pieces by only about 3 mm, so that the gap between the pole pieces and the ferromagnetic surface would be just large enough to permit motion along the surface but not so large as to reduce the magnetic attraction excessively. In addition to the wheel assemblies, the MAGMER would include magnetic adherence enhancement fixtures, which would comprise arrays of permanent magnets and pole pieces

Mass optimization of a small pressure vessel using metal/FRP (fiber reinforced polymers) hybrid structures

International Nuclear Information System (INIS)

Nisar, J.A.; Abdullah, A.N.; Iqbal, N.

2004-01-01

In hybrid pressure vessels, composite (Fiber) is wound over a metallic liner (Steel/Aluminum) in hoop direction. In this concept of hybrid pressure vessel structure, metallic liner takes all the axial loads and fiber reinforced polymers (FRP/sub s/) takes load in circumferential (Hoop) direction. Hybrid structures combine the relatively high shear stiffness and ductility of metal alloy with high specific stiffness, strength and fatigue properties of FRP/sub s/. The relatively simple methods for producing hybrid structures circumvent the need for the complex and expensive equipment that is used for advanced composites processing. This paper presents an efficient way of designing a hybrid pressure vessel where prime concern is weight reduction over an equivalent aluminum structure and investigates various methodologies regarding combinations of metals and FRP/sub s/ for optimization of a given pressure vessel. For this purpose we adopted two different methods of simulation one is computer simulation using ANSYS and other is experimental verification by hydrostatic testing of manufactured pressure vessel. Two different pressure vessels one with aluminum liner and other with steel liner were fabricated. Kevlar 49/epoxy was wrapped around the liners in hoop direction. Both the pressure vessels were put into hydrostatic test. Strains were measured during the test and then converted into corresponding stresses. Results of hydrostatic test were quite in favor of the ANSYS results. In this way we have successfully designed, manufactured and tested the Hybrid pressure vessel saving almost 40% weight in case of aluminum liner and 43.6% in case of steel liner. (author)

Water Loss in Small Settlements

OpenAIRE

Mindaugas Rimeika; Anželika Jurkienė

2014-01-01

The main performance indicators of a water supply system include the quality and safety of water, continuous work, relevant pressure and small water loss. The majority of foreign and local projects on reducing water loss have been carried out in the water supply systems of metropolitans; however, the specificity of small settlements differs from that of big cities. Differences can be observed not only in the development of infrastructure and technical indicators but also in the features of wa...

Genetic variants in novel pathways influence blood pressure and cardiovascular disease risk

NARCIS (Netherlands)

Ehret, Georg B.; Munroe, Patricia B.; Rice, Kenneth M.; Bochud, Murielle; Johnson, Andrew D.; Chasman, Daniel I.; Smith, Albert V.; Tobin, Martin D.; Verwoert, Germaine C.; Hwang, Shih-Jen; Pihur, Vasyl; Vollenweider, Peter; O'Reilly, Paul F.; Amin, Najaf; Bragg-Gresham, Jennifer L.; Teumer, Alexander; Glazer, Nicole L.; Launer, Lenore; Zhao, Jing Hua; Aulchenko, Yurii; Heath, Simon; Sõber, Siim; Parsa, Afshin; Luan, Jian'an; Arora, Pankaj; Dehghan, Abbas; Zhang, Feng; Lucas, Gavin; Hicks, Andrew A.; Jackson, Anne U.; Peden, John F.; Tanaka, Toshiko; Wild, Sarah H.; Rudan, Igor; Igl, Wilmar; Milaneschi, Yuri; Parker, Alex N.; Fava, Cristiano; Chambers, John C.; Fox, Ervin R.; Kumari, Meena; Go, Min Jin; van der Harst, Pim; Kao, Wen Hong Linda; Sjögren, Marketa; Vinay, D. G.; Alexander, Myriam; Tabara, Yasuharu; Shaw-Hawkins, Sue; Whincup, Peter H.; Liu, Yongmei; Shi, Gang; Kuusisto, Johanna; Tayo, Bamidele; Seielstad, Mark; Sim, Xueling; Nguyen, Khanh-Dung Hoang; Lehtimäki, Terho; Matullo, Giuseppe; Wu, Ying; Gaunt, Tom R.; Onland-Moret, N. Charlotte; Cooper, Matthew N.; Platou, Carl G. P.; Org, Elin; Hardy, Rebecca; Dahgam, Santosh; Palmen, Jutta; Vitart, Veronique; Braund, Peter S.; Kuznetsova, Tatiana; Uiterwaal, Cuno S. P. M.; Adeyemo, Adebowale; Palmas, Walter; Campbell, Harry; Ludwig, Barbara; Tomaszewski, Maciej; Tzoulaki, Ioanna; Palmer, Nicholette D.; Aspelund, Thor; Garcia, Melissa; Chang, Yen-Pei C.; O'Connell, Jeffrey R.; Steinle, Nanette I.; Grobbee, Diederick E.; Arking, Dan E.; Kardia, Sharon L.; Morrison, Alanna C.; Hernandez, Dena; Najjar, Samer; McArdle, Wendy L.; Hadley, David; Brown, Morris J.; Connell, John M.; Hingorani, Aroon D.; Day, Ian N. M.; Lawlor, Debbie A.; Beilby, John P.; Lawrence, Robert W.; Clarke, Robert; Hopewell, Jemma C.; Ongen, Halit; Dreisbach, Albert W.; Li, Yali; Young, J. Hunter; Bis, Joshua C.; Kähönen, Mika; Viikari, Jorma; Adair, Linda S.; Lee, Nanette R.; Chen, Ming-Huei; Olden, Matthias; Pattaro, Cristian; Bolton, Judith A. Hoffman; Köttgen, Anna; Bergmann, Sven; Mooser, Vincent; Chaturvedi, Nish; Frayling, Timothy M.; Islam, Muhammad; Jafar, Tazeen H.; Erdmann, Jeanette; Kulkarni, Smita R.; Bornstein, Stefan R.; Grässler, Jürgen; Groop, Leif; Voight, Benjamin F.; Kettunen, Johannes; Howard, Philip; Taylor, Andrew; Guarrera, Simonetta; Ricceri, Fulvio; Emilsson, Valur; Plump, Andrew; Barroso, Inês; Khaw, Kay-Tee; Weder, Alan B.; Hunt, Steven C.; Sun, Yan V.; Bergman, Richard N.; Collins, Francis S.; Bonnycastle, Lori L.; Scott, Laura J.; Stringham, Heather M.; Peltonen, Leena; Perola, Markus; Vartiainen, Erkki; Brand, Stefan-Martin; Staessen, Jan A.; Wang, Thomas J.; Burton, Paul R.; Artigas, Maria Soler; Dong, Yanbin; Snieder, Harold; Wang, Xiaoling; Zhu, Haidong; Lohman, Kurt K.; Rudock, Megan E.; Heckbert, Susan R.; Smith, Nicholas L.; Wiggins, Kerri L.; Doumatey, Ayo; Shriner, Daniel; Veldre, Gudrun; Viigimaa, Margus; Kinra, Sanjay; Prabhakaran, Dorairaj; Tripathy, Vikal; Langefeld, Carl D.; Rosengren, Annika; Thelle, Dag S.; Corsi, Anna Maria; Singleton, Andrew; Forrester, Terrence; Hilton, Gina; McKenzie, Colin A.; Salako, Tunde; Iwai, Naoharu; Kita, Yoshikuni; Ogihara, Toshio; Ohkubo, Takayoshi; Okamura, Tomonori; Ueshima, Hirotsugu; Umemura, Satoshi; Eyheramendy, Susana; Meitinger, Thomas; Wichmann, H.-Erich; Cho, Yoon Shin; Kim, Hyung-Lae; Lee, Jong-Young; Scott, James; Sehmi, Joban S.; Zhang, Weihua; Hedblad, Bo; Nilsson, Peter; Smith, George Davey; Wong, Andrew; Narisu, Narisu; Stančáková, Alena; Raffel, Leslie J.; Yao, Jie; Kathiresan, Sekar; O'Donnell, Christopher J.; Schwartz, Stephen M.; Ikram, M. Arfan; Longstreth, W. T.; Mosley, Thomas H.; Seshadri, Sudha; Shrine, Nick R. G.; Wain, Louise V.; Morken, Mario A.; Swift, Amy J.; Laitinen, Jaana; Prokopenko, Inga; Zitting, Paavo; Cooper, Jackie A.; Humphries, Steve E.; Danesh, John; Rasheed, Asif; Goel, Anuj; Hamsten, Anders; Watkins, Hugh; Bakker, Stephan J. L.; van Gilst, Wiek H.; Janipalli, Charles S.; Mani, K. Radha; Yajnik, Chittaranjan S.; Hofman, Albert; Mattace-Raso, Francesco U. S.; Oostra, Ben A.; Demirkan, Ayse; Isaacs, Aaron; Rivadeneira, Fernando; Lakatta, Edward G.; Orru, Marco; Scuteri, Angelo; Ala-Korpela, Mika; Kangas, Antti J.; Lyytikäinen, Leo-Pekka; Soininen, Pasi; Tukiainen, Taru; Würtz, Peter; Ong, Rick Twee-Hee; Dörr, Marcus; Kroemer, Heyo K.; Völker, Uwe; Völzke, Henry; Galan, Pilar; Hercberg, Serge; Lathrop, Mark; Zelenika, Diana; Deloukas, Panos; Mangino, Massimo; Spector, Tim D.; Zhai, Guangju; Meschia, James F.; Nalls, Michael A.; Sharma, Pankaj; Terzic, Janos; Kumar, M. V. Kranthi; Denniff, Matthew; Zukowska-Szczechowska, Ewa; Wagenknecht, Lynne E.; Fowkes, F. Gerald R.; Charchar, Fadi J.; Schwarz, Peter E. H.; Hayward, Caroline; Guo, Xiuqing; Rotimi, Charles; Bots, Michiel L.; Brand, Eva; Samani, Nilesh J.; Polasek, Ozren; Talmud, Philippa J.; Nyberg, Fredrik; Kuh, Diana; Laan, Maris; Hveem, Kristian; Palmer, Lyle J.; van der Schouw, Yvonne T.; Casas, Juan P.; Mohlke, Karen L.; Vineis, Paolo; Raitakari, Olli; Ganesh, Santhi K.; Wong, Tien Y.; Tai, E. Shyong; Cooper, Richard S.; Laakso, Markku; Rao, Dabeeru C.; Harris, Tamara B.; Morris, Richard W.; Dominiczak, Anna F.; Kivimaki, Mika; Marmot, Michael G.; Miki, Tetsuro; Saleheen, Danish; Chandak, Giriraj R.; Coresh, Josef; Navis, Gerjan; Salomaa, Veikko; Han, Bok-Ghee; Zhu, Xiaofeng; Kooner, Jaspal S.; Melander, Olle; Ridker, Paul M.; Bandinelli, Stefania; Gyllensten, Ulf B.; Wright, Alan F.; Wilson, James F.; Ferrucci, Luigi; Farrall, Martin; Tuomilehto, Jaakko; Pramstaller, Peter P.; Elosua, Roberto; Soranzo, Nicole; Sijbrands, Eric J. G.; Altshuler, David; Loos, Ruth J. F.; Shuldiner, Alan R.; Gieger, Christian; Meneton, Pierre; Uitterlinden, Andre G.; Wareham, Nicholas J.; Gudnason, Vilmundur; Rotter, Jerome I.; Rettig, Rainer; Uda, Manuela; Strachan, David P.; Witteman, Jacqueline C. M.; Hartikainen, Anna-Liisa; Beckmann, Jacques S.; Boerwinkle, Eric; Vasan, Ramachandran S.; Boehnke, Michael; Larson, Martin G.; Järvelin, Marjo-Riitta; Psaty, Bruce M.; Abecasis, Gonçalo R.; Chakravarti, Aravinda; Elliott, Paul; van Duijn, Cornelia M.; Newton-Cheh, Christopher; Levy, Daniel; Caulfield, Mark J.; Johnson, Toby; Tang, Hua; Knowles, Joshua; Hlatky, Mark; Fortmann, Stephen; Assimes, Themistocles L.; Quertermous, Thomas; Go, Alan; Iribarren, Carlos; Absher, Devin; Risch, Neil; Myers, Richard; Sidney, Steven; Ziegler, Andreas; Schillert, Arne; Bickel, Christoph; Sinning, Christoph; Rupprecht, Hans J.; Lackner, Karl; Wild, Philipp; Schnabel, Renate; Blankenberg, Stefan; Zeller, Tanja; Münzel, Thomas; Perret, Claire; Cambien, Francois; Tiret, Laurence; Nicaud, Viviane; Proust, Carole; Uitterlinden, Andre; van Duijn, Cornelia; Whitteman, Jaqueline; Cupples, L. Adrienne; Demissie-Banjaw, Serkalem; Ramachandran, Vasan; Smith, Albert; Folsom, Aaron; Morrison, Alanna; Chen, Ida Yii-Der; Bis, Joshua; Volcik, Kelly; Rice, Kenneth; Taylor, Kent D.; Marciante, Kristin; Smith, Nicholas; Glazer, Nicole; Heckbert, Susan; Harris, Tamara; Lumley, Thomas; Kong, Augustine; Thorleifsson, Gudmar; Thorgeirsson, Gudmundur; Holm, Hilma; Gulcher, Jeffrey R.; Stefansson, Kari; Andersen, Karl; Gretarsdottir, Solveig; Thorsteinsdottir, Unnur; Preuss, Michael; Schreiber, Stefan; König, Inke R.; Lieb, Wolfgang; Hengstenberg, Christian; Schunkert, Heribert; Fischer, Marcus; Grosshennig, Anika; Medack, Anja; Stark, Klaus; Linsel-Nitschke, Patrick; Bruse, Petra; Aherrahrou, Zouhair; Peters, Annette; Loley, Christina; Willenborg, Christina; Nahrstedt, Janja; Freyer, Jennifer; Gulde, Stephanie; Doering, Angela; Meisinger, Christina; Klopp, Norman; Illig, Thomas; Meinitzer, Andreas; Tomaschitz, Andreas; Halperin, Eran; Dobnig, Harald; Scharnagl, Hubert; Kleber, Marcus; Laaksonen, Reijo; Pilz, Stefan; Grammer, Tanja B.; Stojakovic, Tatjana; Renner, Wilfried; März, Winfried; Böhm, Bernhard O.; Winkelmann, Bernhard R.; Winkler, Karl; Hoffmann, Michael M.; Siscovick, David S.; Musunuru, Kiran; Barbalic, Maja; Guiducci, Candace; Burtt, Noel; Gabriel, Stacey B.; Stewart, Alexandre F. R.; Wells, George A.; Chen, Li; Jarinova, Olga; Roberts, Robert; McPherson, Ruth; Dandona, Sonny; Pichard, Augusto D.; Rader, Daniel J.; Devaney, Joe; Lindsay, Joseph M.; Kent, Kenneth M.; Qu, Liming; Satler, Lowell; Burnett, Mary Susan; Li, Mingyao; Reilly, Muredach P.; Wilensky, Robert; Waksman, Ron; Epstein, Stephen; Matthai, William; Knouff, Christopher W.; Waterworth, Dawn M.; Hakonarson, Hakon H.; Walker, Max C.; Hall, Alistair S.; Balmforth, Anthony J.; Wright, Benjamin J.; Nelson, Chris; Thompson, John R.; Ball, Stephen G.; Felix, Janine F.; Demissie, Serkalem; Loehr, Laura R.; Rosamond, Wayne D.; Folsom, Aaron R.; Benjamin, Emelia; Aulchenko, Yurii S.; Haritunians, Talin; Couper, David; Murabito, Joanne; Wang, Ying A.; Stricker, Bruno H.; Gottdiener, John S.; Chang, Patricia P.; Willerson, James T.; Köttgen, A.; Pattaro, C.; Böger, C. A.; Fuchsberger, C.; Olden, M.; Glazer, N. L.; Parsa, A.; Gao, X.; Yang, Q.; Smith, A. V.; O'Connell, J. R.; Li, M.; Schmidt, H.; Tanaka, T.; Isaacs, A.; Ketkar, S.; Hwang, S. J.; Johnson, A. D.; Dehghan, A.; Teumer, A.; Paré, G.; Atkinson, E. J.; Zeller, T.; Lohman, K.; Cornelis, M. C.; Probst-Hensch, N. M.; Kronenberg, F.; Tönjes, A.; Hayward, C.; Aspelund, T.; Eiriksdottir, G.; Launer, L. J.; Harris, T. B.; Rampersaud, E.; Mitchell, B. D.; Arking, D. E.; Boerwinkle, E.; Struchalin, M.; Cavalieri, M.; Singleton, A.; Giallauria, F.; Metter, J.; de Boer, J.; Haritunians, T.; Lumley, T.; Siscovick, D.; Psaty, B. M.; Zillikens, M. C.; Oostra, B. A.; Feitosa, M.; Province, M.; de Andrade, M.; Turner, S. T.; Schillert, A.; Ziegler, A.; Wild, P. S.; Schnabel, R. B.; Wilde, S.; Munzel, T. F.; Leak, T. S.; Illig, T.; Klopp, N.; Meisinger, C.; Wichmann, H. E.; Koenig, W.; Zgaga, L.; Zemunik, T.; Kolcic, I.; Minelli, C.; Hu, F. B.; Johansson, A.; Igl, W.; Zaboli, G.; Wild, S. H.; Wright, A. F.; Campbell, H.; Ellinghaus, D.; Schreiber, S.; Aulchenko, Y. S.; Felix, J. F.; Rivadeneira, F.; Uitterlinden, A. G.; Hofman, A.; Imboden, M.; Nitsch, D.; Brandstätter, A.; Kollerits, B.; Kedenko, L.; Mägi, R.; Stumvoll, M.; Kovacs, P.; Boban, M.; Campbell, S.; Endlich, K.; Völzke, H.; Kroemer, H. K.; Nauck, M.; Völker, U.; Polasek, O.; Vitart, V.; Badola, S.; Parker, A. N.; Ridker, P. M.; Kardia, S. L.; Blankenberg, S.; Liu, Y.; Curhan, G. C.; Franke, A.; Rochat, T.; Paulweber, B.; Prokopenko, I.; Wang, W.; Gudnason, V.; Shuldiner, A. R.; Coresh, J.; Schmidt, R.; Ferrucci, L.; Shlipak, M. G.; van Duijn, C. M.; Borecki, I.; Krämer, B. K.; Rudan, I.; Gyllensten, U.; Wilson, J. F.; Witteman, J. C.; Pramstaller, P. P.; Rettig, R.; Hastie, N.; Chasman, D. I.; Kao, W. H.; Heid, I. M.; Fox, C. S.; Vasan, R. S.; Lieb, W.; Felix, S. B.; Watzinger, N.; Larson, M. G.; Smith, N. L.; Grosshennig, A.; Kathiresan, S.; König, I. R.; Homuth, G.; Aragam, J.; Bis, J. C.; Erdmann, J.; Dörr, M.; Zweiker, R.; Lind, L.; Rodeheffer, R. J.; Greiser, K. H.; Levy, D.; Deckers, J. W.; Stritzke, J.; Lackner, K. J.; Ingelsson, E.; Kullo, I.; Haerting, J.; O'Donnell, C. J.; Heckbert, S. R.; Stricker, B. H.; Reffelmann, T.; Redfield, M. M.; Werdan, K.; Mitchell, G. F.; Rice, K.; Arnett, D. K.; Gottdiener, J. S.; Meitinger, T.; Blettner, M.; Friedrich, N.; Wang, T. J.; Benjamin, E. J.; Rotter, J. I.; Schunkert, H.; Chambers, J. C.; Zhang, W.; Lord, G. M.; van der Harst, P.; Lawlor, D. A.; Sehmi, J. S.; Gale, D. P.; Wass, M. N.; Ahmadi, K. R.; Bakker, S. J.; Beckmann, J.; Bilo, H. J.; Bochud, M.; Brown, M. J.; Caulfield, M. J.; Connell, J. M.; Cook, H. T.; Cotlarciuc, I.; Davey Smith, G.; de Silva, R.; Deng, G.; Devuyst, O.; Dikkeschei, L. D.; Dimkovic, N.; Dockrell, M.; Dominiczak, A.; Ebrahim, S.; Eggermann, T.; Farrall, M.; Floege, J.; Forouhi, N. G.; Gansevoort, R. T.; Han, X.; Hedblad, B.; Homan van der Heide, J. J.; Hepkema, B. G.; Hernandez-Fuentes, M.; Hypponen, E.; Johnson, T.; de Jong, P. E.; Kleefstra, N.; Lagou, V.; Lapsley, M.; Li, Y.; Loos, R. J.; Luan, J.; Luttropp, K.; Maréchal, C.; Melander, O.; Munroe, P. B.; Nordfors, L.; Peltonen, L.; Penninx, B. W.; Perucha, E.; Pouta, A.; Roderick, P. J.; Ruokonen, A.; Samani, N. J.; Sanna, S.; Schalling, M.; Schlessinger, D.; Schlieper, G.; Seelen, M. A.; Sjögren, M.; Smit, J. H.; Snieder, H.; Soranzo, N.; Spector, T. D.; Stenvinkel, P.; Sternberg, M. J.; Swaminathan, R.; Ubink-Veltmaat, L. J.; Uda, M.; Vollenweider, P.; Wallace, C.; Waterworth, D.; Zerres, K.; Waeber, G.; Wareham, N. J.; Maxwell, P. H.; McCarthy, M. I.; Jarvelin, M. R.; Mooser, V.; Abecasis, G. R.; Lightstone, L.; Scott, J.; Navis, G.; Elliott, P.; Kooner, J. S.

2011-01-01

Blood pressure is a heritable trait influenced by several biological pathways and responsive to environmental stimuli. Over one billion people worldwide have hypertension (≥140 mm Hg systolic blood pressure or  ≥90 mm Hg diastolic blood pressure). Even small increments in blood pressure are

[Development of a continuous blood pressure monitoring and recording system].

Science.gov (United States)

Zhang, Yang; Li, Yong; Gao, Shumei; Song, Yilin

2012-09-01

A small experimental system is constructed with working principle of continuous blood pressure monitoring based on the volume compensation method. The preliminary experimental results show that the system can collect blood pressure signals at the radial artery effectively. The digital PID algorithm can track the variation of blood pressure. And the accuracy of continuous blood pressure detecting achieve the level of same kind of product.

Mesoscale modeling of the water vapor cycle at Mawrth Vallis: a Mars2020 and ExoMars exploration rovers high-priority landing site

Science.gov (United States)

Pla-García, Jorge

2017-04-01

Introduction: The Mars Regional Atmospheric Modeling System (MRAMS) was used to predict meteorological conditions that are likely to be encountered by the Mars 2020 (NASA) Rover at several of their respective proposed landing sites during entry, descent, and landing at Ls5 [1] and by the ExoMars (ESA) Rover at one of the final landing sites. MRAMS is ideally suited for this type of investigation; the model is explicitly designed to simu-late Mars' atmospheric circulations at the mesoscale and smaller with realistic, high-resolution surface proper-ties [2, 3]. One of the sights studied for both rovers was Mawrth Vallis (MV), an ancient water outflow channel with light colored clay-rich rocks in the mid-latitude north hemisphere (Oxia Palus quadrangle). MV is the northernmost of the Mars2020 and ExoMars landing sites and the closest to the northern polar cap water source. The primary source of water vapor to the atmosphere is the northern polar cap during the northern summer. In order to highlight MV habitability implications, additional numerical experiments at Ls90, 140 and 180, highest column abundance of water vapor is found over MV [4], were performed to study how the atmospheric circulation connects MV with the polar water source. Once the winter CO2 retreats, the underlying polar water ice is exposed and begins to sublimate. The water is transported equatorward where it is manifested in the tropical aphelion cloud belt. If transport is assumed to be the result of the summer Hadley Cell, then the polar water is carried aloft in the northern high latitude rising branch before moving equatorward and eventually toward the southern high latitudes. Thus, the mean meridional summer circulation precludes a direct water vapor connection between MV and the polar source. Around the equinoxes (Ls0 and Ls180), there is a brief transition period where the rising branch quickly crosses from one hemisphere into the other as it migrates to its more typical solstitial location

Tearing modes with pressure gradient effect in pair plasmas

International Nuclear Information System (INIS)

Cai Huishan; Li Ding; Zheng Jian

2009-01-01

The general dispersion relation of tearing mode with pressure gradient effect in pair plasmas is derived analytically. If the pressure gradients of positron and electron are not identical in pair plasmas, the pressure gradient has significant influence at tearing mode in both collisionless and collisional regimes. In collisionless regime, the effects of pressure gradient depend on its magnitude. For small pressure gradient, the growth rate of tearing mode is enhanced by pressure gradient. For large pressure gradient, the growth rate is reduced by pressure gradient. The tearing mode can even be stabilized if pressure gradient is large enough. In collisional regime, the growth rate of tearing mode is reduced by the pressure gradient. While the positron and electron have equal pressure gradient, tearing mode is not affected by pressure gradient in pair plasmas.

Variable g- Mars environmental chamber: a small window of the martian environment for life science investigations

Science.gov (United States)

Sgambati, Antonella; Slenzka, Klaus; Schmeyers, Bernd; Di Capua, Massimiliano; Harting, Benjamin

Human exploration and permanent settlement on the Martian surface is the one of the most attractive and ambitious endeavors mankind has ever faced. As technology and research progress, solutions and information that were before unavailable are slowly making the dream become everyday more feasible. In the past years a huge amount of knowledge was gathered by the Mars Exploration Rovers Spirit and Opportunity and now, even more insight is being gathered through the latest rover of the family, Curiosity. In this work, data from the various missions will be used to define and reproduce on Earth the characteristic Martian atmospheric conditions. A small Mars environmental chamber has been designed and built with the objective of studying the effects of the Martian environment on biological systems. The Variable gravity Mars Environmental Chamber (VgMEC) will allow researchers to replicate atmospheric pressure, gas composition, temperature and UVA/B exposure typical of the equatorial regions of Mars. By exposing biological systems to a controllable set of stressor it will be possible to identify both multi and single stressor effects on the system of interest. While several Mars environment simulation facilities exist, due to their size and mass, all are confined to floor-fixed laboratory settings. The VgMEC is an OHB funded project that wishes to bring together the scientific community and the industry. Collaborations will be enabled by granting low cost access to cutting-edge instrumentation and services. Developed at OHB System AG, VgMEC has been designed from the ground up to be a 28L, compact and lightweight test volume capable of being integrated in existing centrifuges (such as the ESA-ESTEC LCD), gimbal systems and parabolic flight aircraft. The VgMEC support systems were designed to accommodate continuous operations of virtually unlimited duration through the adoption of solutions such as: hot swappable gas/liquid consumables bottles, low power requirements, an

The Proposed Mars Astrobiology Explorer - Cacher [MAX-C] Rover: First Step in a Potential Sample Return Campaign

Science.gov (United States)

Allen, Carlton C.; Beaty, David W.

2010-01-01

Sample return from Mars has been advocated by numerous scientific advisory panels for over 30 years, most prominently beginning with the National Research Council s [1] strategy for the exploration of the inner solar system, and most recently by the Mars Exploration Program Analysis Group (MEPAG s) Next Decade Science Analysis Group [2]. Analysis of samples here on Earth would have enormous advantages over in situ analyses in producing the data quality needed to address many of the complex scientific questions the community has posed about Mars. Instead of a small, predetermined set of analytical techniques, state of the art preparative and instrumental resources of the entire scientific community could be applied to the samples. The analytical emphasis could shift as the meaning of each result becomes better appreciated. These arguments apply both to igneous rocks and to layered sedimentary materials, either of which could contain water and other volatile constituents. In 2009 MEPAG formed the Mid-Range Rover Science Analysis Group (MRR-SAG) to formulate a mission concept that would address two general objectives: (1) conduct high-priority in situ science and (2) make concrete steps towards the potential return of samples to Earth. This analysis resulted in a mission concept named the Mars Astrobiology Explorer-Cacher (MAX-C), which was envisioned for launch in the 2018 opportunity. After extensive discussion, this group concluded that by far the most definitive contribution to sample return by this mission would be to collect and cache, in an accessible location, a suite of compelling samples that could potentially be recovered and returned by a subsequent mission. This would have the effect of separating two of the essential functions of MSR, the acquisition of the sample collection and its delivery to martian orbit, into two missions.

Numerical Analysis on Transient of Steam-gas Pressurizer

International Nuclear Information System (INIS)

Kim, Jong-Won; Lee, Yeon-Gun; Park, Goon-Cherl

2008-01-01

In nuclear reactors, various pressurizers are adopted to satisfy their characteristics and uses. The additional active systems such as heater, pressurizer cooler, spray and insulator are essential for a steam or a gas pressurizer. With a steam-gas pressurizer, additional systems are not required due to the use of steam and non-condensable gas as pressure-buffering materials. The steam-gas pressurizer in integrated small reactors experiences very complicated thermal-hydraulic phenomena. To ensure the integrity of this pressurizer type, the analysis on the transient behavior of the steam-gas pressure is indispensable. For this purpose, the steam-gas pressurizer model is introduced to predict the accurate system pressure. The proposed model includes bulk flashing, rainout, inter-region heat and mass transfer and wall condensation with non-condensable gas. However, the ideal gas law is not applied because of significant interaction at high pressure between steam and non-condensable gas. The results obtained from this proposed model agree with those from pressurizer tests. (authors)

Condensation heat transfer on natural convection at the high pressure

International Nuclear Information System (INIS)

Jong-Won, Kim; Hyoung-Kyoun, Ahn; Goon-Cherl, Park

2007-01-01

The Regional Energy Research Institute for the Next Generation is to develop a small scale electric power system driven by an environment-friendly and stable small nuclear reactor. REX-10 has been developed to assure high system safety in order to be placed in densely populated region and island. REX-10 adopts the steam-gas pressurizer to assure the inherent safety. The thermal-hydraulic phenomena in the steam-gas pressurizer are very complex. Especially, the condensation heat transfer with noncondensable gas on the natural convection is important to evaluate the pressurizer behavior. However, there have been few investigations on the condensation in the presence of noncondensable gas at the high pressure. In this study, the theoretical model is developed to estimate the condensation heat transfer at the high pressure using heat and mass transfer analogy. The analysis results show good agreement with correlations and experimental data. It is found that the condensation heat transfer coefficient increases as the total pressure increases or the mass fraction of the non-condensable gas decreases. In addition, the heat transfer coefficient no more increases over the specific pressure

Pressurized waterproof case for electronic device

KAUST Repository

Berumen, Michael L.

2013-01-31

The pressurized waterproof case for an electronic device is particularly adapted for the waterproof containment and operation of a touch-screen computer or the like therein at some appreciable water depth. The case may be formed as an enclosure having an open top panel or face covered by a flexible, transparent membrane or the like for the operation of the touch-screen device within the case. A pressurizing system is provided for the case to pressurize the case and the electronic device therein to slightly greater than ambient in order to prevent the external water pressure from bearing against the transparent membrane and pressing it against the touch screen, thereby precluding operation of the touch screen device within the case. The pressurizing system may be a small gas cartridge (e.g., CO2), or may be provided from an external source, such as the diver\\'s breathing air. A pressure relief valve is also provided.

Characterization of terrestrial hydrothermal alteration products with Mars analog instrumentation: Implications for current and future rover investigations

Science.gov (United States)

Black, Sarah R.; Hynek, Brian M.

2018-06-01

host a wide range of microbial life here on Earth-are of high interest and it is likely that future rovers will encounter similar mineral assemblages. Therefore, future rovers would benefit from using a combination of these methods and expanding the VSWIR sampling range to the full 300-2500 nm to conduct a comprehensive mineralogical investigation.

Wave effects on a pressure sensor

Digital Repository Service at National Institute of Oceanography (India)

Joseph, A.; DeSa, E; Desa, E; McKeown, J.; Peshwe, V.B.

Wave flume experiments indicated that for waves propagating on quiescent waters the sensor's performance improved (i.e. the difference Delta P between the average hydrostatic and measured pressures was small and positive) when the inlet...

Probabilistic integrity assessment of pressure tubes in an operating pressurized heavy water reactor

Energy Technology Data Exchange (ETDEWEB)

Oh, Young-Jin; Park, Heung-Bae [KEPCO E and C, 188 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do 463-870 (Korea, Republic of); Lee, Jung-Min; Kim, Young-Jin [School of Mechanical Engineering, Sungkyunkwan University, 300 Chunchun-dong, Jangan-gu, Suwon-si, Gyeonggi-do 440-746 (Korea, Republic of); Ko, Han-Ok [Korea Institute of Nuclear Safety, 34 Gwahak-ro, Yuseong-gu, Daejeon-si 305-338 (Korea, Republic of); Chang, Yoon-Suk, E-mail: yschang@khu.ac.kr [Department of Nuclear Engineering, Kyung Hee University, 1 Seocheon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of)

2012-02-15

Even though pressure tubes are major components of a pressurized heavy water reactor (PHWR), only small proportions of pressure tubes are sampled for inspection due to limited inspection time and costs. Since the inspection scope and integrity evaluation have been treated by using a deterministic approach in general, a set of conservative data was used instead of all known information related to in-service degradation mechanisms because of inherent uncertainties in the examination. Recently, in order that pressure tube degradations identified in a sample of inspected pressure tubes are taken into account to address the balance of the uninspected ones in the reactor core, a probabilistic approach has been introduced. In the present paper, probabilistic integrity assessments of PHWR pressure tubes were carried out based on accumulated operating experiences and enhanced technology. Parametric analyses on key variables were conducted, which were periodically measured by in-service inspection program, such as deuterium uptake rate, dimensional change rate of pressure tube and flaw size distribution. Subsequently, a methodology to decide optimum statistical distribution by using a robust method adopting a genetic algorithm was proposed and applied to the most influential variable to verify the reliability of the proposed method. Finally, pros and cons of the alternative distributions comparing with corresponding ones derived from the traditional method as well as technical findings from the statistical assessment were discussed to show applicability to the probabilistic assessment of pressure tubes.

Slope instability caused by small variations in hydraulic conductivity

Science.gov (United States)

Reid, M.E.

1997-01-01

Variations in hydraulic conductivity can greatly modify hillslope ground-water flow fields, effective-stress fields, and slope stability. In materials with uniform texture, hydraulic conductivities can vary over one to two orders of magnitude, yet small variations can be difficult to determine. The destabilizing effects caused by small (one order of magnitude or less) hydraulic conductivity variations using ground-water flow modeling, finite-element deformation analysis, and limit-equilibrium analysis are examined here. Low hydraulic conductivity materials that impede downslope ground-water flow can create unstable areas with locally elevated pore-water pressures. The destabilizing effects of small hydraulic heterogeneities can be as great as those induced by typical variations in the frictional strength (approximately 4??-8??) of texturally similar materials. Common "worst-case" assumptions about ground-water flow, such as a completely saturated "hydrostatic" pore-pressure distribution, do not account for locally elevated pore-water pressures and may not provide a conservative slope stability analysis. In site characterization, special attention should be paid to any materials that might impede downslope ground-water flow and create unstable regions.

Water-Pressure Distribution on Seaplane Float

Science.gov (United States)

Thompson, F L

1929-01-01

The investigation presented in this report was conducted for the purpose of determining the distribution and magnitude of water pressures likely to be experienced on seaplane hulls in service. It consisted of the development and construction of apparatus for recording water pressures lasting one one-hundredth second or longer and of flight tests to determine the water pressures on a UO-1 seaplane float under various conditions of taxiing, taking off, and landing. The apparatus developed was found to operate with satisfactory accuracy and is suitable for flight tests on other seaplanes. The tests on the UO-1 showed that maximum pressures of about 6.5 pounds per square inch occur at the step for the full width of the float bottom. Proceeding forward from the step the maximum pressures decrease in magnitude uniformly toward the bow, and the region of highest pressures narrows toward the keel. Immediately abaft the step the maximum pressures are very small, but increase in magnitude toward the stern and there once reached a value of about 5 pounds per square inch. (author)

A transparent bending-insensitive pressure sensor

Science.gov (United States)

Lee, Sungwon; Reuveny, Amir; Reeder, Jonathan; Lee, Sunghoon; Jin, Hanbit; Liu, Qihan; Yokota, Tomoyuki; Sekitani, Tsuyoshi; Isoyama, Takashi; Abe, Yusuke; Suo, Zhigang; Someya, Takao

2016-05-01

Measuring small normal pressures is essential to accurately evaluate external stimuli in curvilinear and dynamic surfaces such as natural tissues. Usually, sensitive and spatially accurate pressure sensors are achieved through conformal contact with the surface; however, this also makes them sensitive to mechanical deformation (bending). Indeed, when a soft object is pressed by another soft object, the normal pressure cannot be measured independently from the mechanical stress. Here, we show a pressure sensor that measures only the normal pressure, even under extreme bending conditions. To reduce the bending sensitivity, we use composite nanofibres of carbon nanotubes and graphene. Our simulations show that these fibres change their relative alignment to accommodate bending deformation, thus reducing the strain in individual fibres. Pressure sensitivity is maintained down to a bending radius of 80 μm. To test the suitability of our sensor for soft robotics and medical applications, we fabricated an integrated sensor matrix that is only 2 μm thick. We show real-time (response time of ∼20 ms), large-area, normal pressure monitoring under different, complex bending conditions.

Characteristics of CO/sub 2/ TE-amplifiers with different uv preionization at superatmospheric pressure with doping additives

Energy Technology Data Exchange (ETDEWEB)

Huebner, H; Homann, C [Technische Univ. Hannover (Germany, F.R.). Inst. fuer Plasmaphysik

1977-02-01

The attainable maximum pressure and the small signal gain are compared at pressures up to 3 bar in a TE-CO/sub 2/ laser amplifier with two preionization systems. It is found that doping with tripopylamine increases the attainable pressure for glow discharges but decreases the small signal gain. At slightly superatmospheric pressure and low doping amount the simple Lamberton-Pearson device gives the best results. For constant input energy the inversion grows with increasing total pressure.

PWR cold-leg small break loca with faulty HPI

International Nuclear Information System (INIS)

Kumamaru, H.; Kukita, Y.

1991-01-01

The ROSA-IV Large Scale Test Facility (LSTF) is a 1/48 volumetrically-scaled model of a pressurized water reactor (PWR). At the LSTF are performed cold-leg small-break loss-of-coolant accident (LOCA) tests with faulty high pressure injection (HPI) system for break areas from 0.5% to 10% and an intentional primary system depressurization test following a small-break LOCA test. A simple prediction model is proposed for prediction of times of major events. Test data and calculations show that intentional primary system depressurization with use of the pressurizer power-operated relief valves (PORVs) is effective for break areas of approximately 0.5% or less, is unnecessary for breaks of 5% or more, and is insufficient for intermediate break areas to maintain adequate core cooling. (author)

Volcanic history of the Imbrium basin: A close-up view from the lunar rover Yutu.

Science.gov (United States)

Zhang, Jinhai; Yang, Wei; Hu, Sen; Lin, Yangting; Fang, Guangyou; Li, Chunlai; Peng, Wenxi; Zhu, Sanyuan; He, Zhiping; Zhou, Bin; Lin, Hongyu; Yang, Jianfeng; Liu, Enhai; Xu, Yuchen; Wang, Jianyu; Yao, Zhenxing; Zou, Yongliao; Yan, Jun; Ouyang, Ziyuan

2015-04-28

We report the surface exploration by the lunar rover Yutu that landed on the young lava flow in the northeastern part of the Mare Imbrium, which is the largest basin on the nearside of the Moon and is filled with several basalt units estimated to date from 3.5 to 2.0 Ga. The onboard lunar penetrating radar conducted a 114-m-long profile, which measured a thickness of ∼5 m of the lunar regolith layer and detected three underlying basalt units at depths of 195, 215, and 345 m. The radar measurements suggest underestimation of the global lunar regolith thickness by other methods and reveal a vast volume of the last volcano eruption. The in situ spectral reflectance and elemental analysis of the lunar soil at the landing site suggest that the young basalt could be derived from an ilmenite-rich mantle reservoir and then assimilated by 10-20% of the last residual melt of the lunar magma ocean.

Middleware and Web Services for the Collaborative Information Portal of NASA's Mars Exploration Rovers Mission

Science.gov (United States)

Sinderson, Elias; Magapu, Vish; Mak, Ronald

2004-01-01

We describe the design and deployment of the middleware for the Collaborative Information Portal (CIP), a mission critical J2EE application developed for NASA's 2003 Mars Exploration Rover mission. CIP enabled mission personnel to access data and images sent back from Mars, staff and event schedules, broadcast messages and clocks displaying various Earth and Mars time zones. We developed the CIP middleware in less than two years time usins cutting-edge technologies, including EJBs, servlets, JDBC, JNDI and JMS. The middleware was designed as a collection of independent, hot-deployable web services, providing secure access to back end file systems and databases. Throughout the middleware we enabled crosscutting capabilities such as runtime service configuration, security, logging and remote monitoring. This paper presents our approach to mitigating the challenges we faced, concluding with a review of the lessons we learned from this project and noting what we'd do differently and why.

Heat transfer characteristics and operation limit of pressurized hybrid heat pipe for small modular reactors

International Nuclear Information System (INIS)

Kim, Kyung Mo; Bang, In Cheol

2017-01-01

Highlights: • Thermal performances and operation limits of hybrid heat pipe were experimentally studied. • Models for predicting the operation limit of the hybrid heat pipe was developed. • Non-condensable gas affected heat transfer characteristics of the hybrid heat pipe. - Abstract: In this paper, a hybrid heat pipe is proposed for use in advanced nuclear power plants as a passive heat transfer device. The hybrid heat pipe combines the functions of a heat pipe and a control rod to simultaneously remove the decay heat generated from the core and shutdown the reactor under accident conditions. Thus, the hybrid heat pipe contains a neutron absorber in the evaporator section, which corresponds to the core of the reactor pressure vessel. The presence of the neutron absorber material leads to differences in the heated diameter and hydraulic diameter of the heat pipe. The cross-sectional areas of the vapor paths through the evaporator, adiabatic, and condenser sections are also different. The hybrid heat pipe must operate in a high-temperature, high-pressure environment to remove the decay heat. In other words, the operating pressure must be higher than those of the commercially available thermosyphons. Hence, the thermal performances, including operation limit of the hybrid heat pipe, were experimentally studied in the operating pressure range of 0.2–20 bar. The operating pressure of the hybrid heat pipe was controlled by charging the non-condensable gas which is unused method to achieve the high saturation pressure in conventional thermosyphons. The effect of operating pressure on evaporation heat transfer was negligible, while condensation heat transfer was affected by the amount of non-condensable gas in the test section. The operation limit of the hybrid heat pipe increased with the operating pressure. Maximum heat removal capacity of the hybrid heat pipe was up to 6 kW which is meaningful value as a passive decay heat removal device in the nuclear power

Automaton Rover for Extreme Environments, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Extreme environments abound in the solar system and include the radiation around Jupiter, high surface temperatures on Mercury and Venus, and hot, high pressure...

Abundance and Isotopic Composition of Gases in the Martian Atmosphere from the Curiosity Rover

Science.gov (United States)

Mahaffy, Paul R.; Webster, Christopher R.; Atreya, Sushil K.; Franz, Heather; Wong, Michael; Conrad, Pamela G.; Harpold, Dan; Jones, John J.; Leshin, Laurie A.; Manning, Heidi; Owen, Tobias; Pepin, Robert O.; Squyres, Steven; Trainer, Melissa; Kemppinen, Osku; Bridges, Nathan; Johnson, Jeffrey R.; Minitti, Michelle; Cremers, David; Bell, James F.; Edgar, Lauren; Farmer, Jack; Godber, Austin; Wadhwa, Meenakshi; Wellington, Danika; McEwan, Ian; Newman, Claire; Richardson, Mark; Charpentier, Antoine; Peret, Laurent; King, Penelope; Blank, Jennifer; Weigle, Gerald; Schmidt, Mariek; Li, Shuai; Milliken, Ralph; Robertson, Kevin; Sun, Vivian; Baker, Michael; Edwards, Christopher; Ehlmann, Bethany; Farley, Kenneth; Griffes, Jennifer; Grotzinger, John; Miller, Hayden; Newcombe, Megan; Pilorget, Cedric; Rice, Melissa; Siebach, Kirsten; Stack, Katie; Stolper, Edward; Brunet, Claude; Hipkin, Victoria; Léveillé, Richard; Marchand, Geneviève; Sánchez, Pablo Sobrón; Favot, Laurent; Cody, George; Steele, Andrew; Flückiger, Lorenzo; Lees, David; Nefian, Ara; Martin, Mildred; Gailhanou, Marc; Westall, Frances; Israël, Guy; Agard, Christophe; Baroukh, Julien; Donny, Christophe; Gaboriaud, Alain; Guillemot, Philippe; Lafaille, Vivian; Lorigny, Eric; Paillet, Alexis; Pérez, René; Saccoccio, Muriel; Yana, Charles; Armiens-Aparicio, Carlos; Rodríguez, Javier Caride; Blázquez, Isaías Carrasco; Gómez, Felipe Gómez; Gómez-Elvira, Javier; Hettrich, Sebastian; Malvitte, Alain Lepinette; Jiménez, Mercedes Marín; Martínez-Frías, Jesús; Martín-Soler, Javier; Martín-Torres, F. Javier; Jurado, Antonio Molina; Mora-Sotomayor, Luis; Caro, Guillermo Muñoz; López, Sara Navarro; Peinado-González, Verónica; Pla-García, Jorge; Manfredi, José Antonio Rodriguez; Romeral-Planelló, Julio José; Fuentes, Sara Alejandra Sans; Martinez, Eduardo Sebastian; Redondo, Josefina Torres; Urqui-O'Callaghan, Roser; Mier, María-Paz Zorzano; Chipera, Steve; Lacour, Jean-Luc; Mauchien, Patrick; Sirven, Jean-Baptiste; Fairén, Alberto; Hayes, Alexander; Joseph, Jonathan; Sullivan, Robert; Thomas, Peter; Dupont, Audrey; Lundberg, Angela; Melikechi, Noureddine; Mezzacappa, Alissa; DeMarines, Julia; Grinspoon, David; Reitz, Günther; Prats, Benito; Atlaskin, Evgeny; Genzer, Maria; Harri, Ari-Matti; Haukka, Harri; Kahanpää, Henrik; Kauhanen, Janne; Kemppinen, Osku; Paton, Mark; Polkko, Jouni; Schmidt, Walter; Siili, Tero; Fabre, Cécile; Wray, James; Wilhelm, Mary Beth; Poitrasson, Franck; Patel, Kiran; Gorevan, Stephen; Indyk, Stephen; Paulsen, Gale; Gupta, Sanjeev; Bish, David; Schieber, Juergen; Gondet, Brigitte; Langevin, Yves; Geffroy, Claude; Baratoux, David; Berger, Gilles; Cros, Alain; d'Uston, Claude; Forni, Olivier; Gasnault, Olivier; Lasue, Jérémie; Lee, Qiu-Mei; Maurice, Sylvestre; Meslin, Pierre-Yves; Pallier, Etienne; Parot, Yann; Pinet, Patrick; Schröder, Susanne; Toplis, Mike; Lewin, Éric; Brunner, Will; Heydari, Ezat; Achilles, Cherie; Oehler, Dorothy; Sutter, Brad; Cabane, Michel; Coscia, David; Israël, Guy; Szopa, Cyril; Dromart, Gilles; Robert, François; Sautter, Violaine; Le Mouélic, Stéphane; Mangold, Nicolas; Nachon, Marion; Buch, Arnaud; Stalport, Fabien; Coll, Patrice; François, Pascaline; Raulin, François; Teinturier, Samuel; Cameron, James; Clegg, Sam; Cousin, Agnès; DeLapp, Dorothea; Dingler, Robert; Jackson, Ryan Steele; Johnstone, Stephen; Lanza, Nina; Little, Cynthia; Nelson, Tony; Wiens, Roger C.; Williams, Richard B.; Jones, Andrea; Kirkland, Laurel; Treiman, Allan; Baker, Burt; Cantor, Bruce; Caplinger, Michael; Davis, Scott; Duston, Brian; Edgett, Kenneth; Fay, Donald; Hardgrove, Craig; Harker, David; Herrera, Paul; Jensen, Elsa; Kennedy, Megan R.; Krezoski, Gillian; Krysak, Daniel; Lipkaman, Leslie; Malin, Michael; McCartney, Elaina; McNair, Sean; Nixon, Brian; Posiolova, Liliya; Ravine, Michael; Salamon, Andrew; Saper, Lee; Stoiber, Kevin; Supulver, Kimberley; Van Beek, Jason; Van Beek, Tessa; Zimdar, Robert; French, Katherine Louise; Iagnemma, Karl; Miller, Kristen; Summons, Roger; Goesmann, Fred; Goetz, Walter; Hviid, Stubbe; Johnson, Micah; Lefavor, Matthew; Lyness, Eric; Breves, Elly; Dyar, M. Darby; Fassett, Caleb; Blake, David F.; Bristow, Thomas; DesMarais, David; Edwards, Laurence; Haberle, Robert; Hoehler, Tori; Hollingsworth, Jeff; Kahre, Melinda; Keely, Leslie; McKay, Christopher; Wilhelm, Mary Beth; Bleacher, Lora; Brinckerhoff, William; Choi, David; Dworkin, Jason P.; Eigenbrode, Jennifer; Floyd, Melissa; Freissinet, Caroline; Garvin, James; Glavin, Daniel; Jones, Andrea; Martin, David K.; McAdam, Amy; Pavlov, Alexander; Raaen, Eric; Smith, Michael D.; Stern, Jennifer; Tan, Florence; Meyer, Michael; Posner, Arik; Voytek, Mary; Anderson, Robert C.; Aubrey, Andrew; Beegle, Luther W.; Behar, Alberto; Blaney, Diana; Brinza, David; Calef, Fred; Christensen, Lance; Crisp, Joy A.; DeFlores, Lauren; Ehlmann, Bethany; Feldman, Jason; Feldman, Sabrina; Flesch, Gregory; Hurowitz, Joel; Jun, Insoo; Keymeulen, Didier; Maki, Justin; Mischna, Michael; Morookian, John Michael; Parker, Timothy; Pavri, Betina; Schoppers, Marcel; Sengstacken, Aaron; Simmonds, John J.; Spanovich, Nicole; Juarez, Manuel de la Torre; Vasavada, Ashwin R.; Yen, Albert; Archer, Paul Douglas; Cucinotta, Francis; Ming, Douglas; Morris, Richard V.; Niles, Paul; Rampe, Elizabeth; Nolan, Thomas; Fisk, Martin; Radziemski, Leon; Barraclough, Bruce; Bender, Steve; Berman, Daniel; Dobrea, Eldar Noe; Tokar, Robert; Vaniman, David; Williams, Rebecca M. E.; Yingst, Aileen; Lewis, Kevin; Cleghorn, Timothy; Huntress, Wesley; Manhès, Gérard; Hudgins, Judy; Olson, Timothy; Stewart, Noel; Sarrazin, Philippe; Grant, John; Vicenzi, Edward; Wilson, Sharon A.; Bullock, Mark; Ehresmann, Bent; Hamilton, Victoria; Hassler, Donald; Peterson, Joseph; Rafkin, Scot; Zeitlin, Cary; Fedosov, Fedor; Golovin, Dmitry; Karpushkina, Natalya; Kozyrev, Alexander; Litvak, Maxim; Malakhov, Alexey; Mitrofanov, Igor; Mokrousov, Maxim; Nikiforov, Sergey; Prokhorov, Vasily; Sanin, Anton; Tretyakov, Vladislav; Varenikov, Alexey; Vostrukhin, Andrey; Kuzmin, Ruslan; Clark, Benton; Wolff, Michael; McLennan, Scott; Botta, Oliver; Drake, Darrell; Bean, Keri; Lemmon, Mark; Schwenzer, Susanne P.; Anderson, Ryan B.; Herkenhoff, Kenneth; Lee, Ella Mae; Sucharski, Robert; Hernández, Miguel Ángel de Pablo; Ávalos, Juan José Blanco; Ramos, Miguel; Kim, Myung-Hee; Malespin, Charles; Plante, Ianik; Muller, Jan-Peter; Navarro-González, Rafael; Ewing, Ryan; Boynton, William; Downs, Robert; Fitzgibbon, Mike; Harshman, Karl; Morrison, Shaunna; Dietrich, William; Kortmann, Onno; Palucis, Marisa; Sumner, Dawn Y.; Williams, Amy; Lugmair, Günter; Wilson, Michael A.; Rubin, David; Jakosky, Bruce; Balic-Zunic, Tonci; Frydenvang, Jens; Jensen, Jaqueline Kløvgaard; Kinch, Kjartan; Koefoed, Asmus; Madsen, Morten Bo; Stipp, Susan Louise Svane; Boyd, Nick; Campbell, John L.; Gellert, Ralf; Perrett, Glynis; Pradler, Irina; VanBommel, Scott; Jacob, Samantha; Rowland, Scott; Atlaskin, Evgeny; Savijärvi, Hannu; Boehm, Eckart; Böttcher, Stephan; Burmeister, Sönke; Guo, Jingnan; Köhler, Jan; García, César Martín; Mueller-Mellin, Reinhold; Wimmer-Schweingruber, Robert; Bridges, John C.; McConnochie, Timothy; Benna, Mehdi; Bower, Hannah; Brunner, Anna; Blau, Hannah; Boucher, Thomas; Carmosino, Marco; Elliott, Harvey; Halleaux, Douglas; Rennó, Nilton; Elliott, Beverley; Spray, John; Thompson, Lucy; Gordon, Suzanne; Newsom, Horton; Ollila, Ann; Williams, Joshua; Vasconcelos, Paulo; Bentz, Jennifer; Nealson, Kenneth; Popa, Radu; Kah, Linda C.; Moersch, Jeffrey; Tate, Christopher; Day, Mackenzie; Kocurek, Gary; Hallet, Bernard; Sletten, Ronald; Francis, Raymond; McCullough, Emily; Cloutis, Ed; ten Kate, Inge Loes; Kuzmin, Ruslan; Arvidson, Raymond; Fraeman, Abigail; Scholes, Daniel; Slavney, Susan; Stein, Thomas; Ward, Jennifer; Berger, Jeffrey; Moores, John E.

2013-07-01

Volume mixing and isotope ratios secured with repeated atmospheric measurements taken with the Sample Analysis at Mars instrument suite on the Curiosity rover are: carbon dioxide (CO2), 0.960(±0.007); argon-40 (40Ar), 0.0193(±0.0001); nitrogen (N2), 0.0189(±0.0003); oxygen, 1.45(±0.09) × 10-3; carbon monoxide, < 1.0 × 10-3; and 40Ar/36Ar, 1.9(±0.3) × 103. The 40Ar/N2 ratio is 1.7 times greater and the 40Ar/36Ar ratio 1.6 times lower than values reported by the Viking Lander mass spectrometer in 1976, whereas other values are generally consistent with Viking and remote sensing observations. The 40Ar/36Ar ratio is consistent with martian meteoritic values, which provides additional strong support for a martian origin of these rocks. The isotopic signature δ13C from CO2 of ~45 per mil is independently measured with two instruments. This heavy isotope enrichment in carbon supports the hypothesis of substantial atmospheric loss.

Chromatographic, Spectroscopic and Mass Spectrometric Approaches for Exploring the Habitability of Mars in 2012 and Beyond with the Curiosity Rover

Science.gov (United States)

Mahaffy, Paul

2012-01-01

The Sample Analysis at Mars (SAM) suite of instruments on the Curiosity Rover of Mars Science Laboratory Mission is designed to provide chemical and isotopic analysis of organic and inorganic volatiles for both atmospheric and solid samples. The goals of the science investigation enabled by the gas chromatograph mass spectrometer and tunable laser spectrometer instruments of SAM are to work together with the other MSL investigations is to quantitatively assess habitability through a series of chemical and geological measurements. We describe the multi-column gas chromatograph system employed on SAM and the approach to extraction and analysis of organic compounds that might be preserved in ancient martian rocks.

Rover Low Gain Antenna Qualification for Deep Space Thermal Environments

Science.gov (United States)

Ramesham, Rajeshuni; Amaro, Luis R.; Brown, Paula R.; Usiskin, Robert; Prater, Jack L.

2013-01-01

A method to qualify the Rover Low Gain Antenna (RLGA) for use during the Mars Science Laboratory (MSL) mission has been devised. The RLGA antenna must survive all ground operations, plus the nominal 670 Martian sol mission that includes the summer and winter seasons of the Mars thermal environment. This qualification effort was performed to verify that the RLGA design, its bonding, and packaging processes are adequate. The qualification test was designed to demonstrate a survival life of three times more than all expected ground testing, plus a nominal 670 Martian sol missions. Baseline RF tests and a visual inspection were performed on the RLGA hardware before the start of the qualification test. Functional intermittent RF tests were performed during thermal chamber breaks over the course of the complete qualification test. For the return loss measurements, the RLGA antenna was moved to a test area. A vector network analyzer was calibrated over the operational frequency range of the antenna. For the RLGA, a simple return loss measurement was performed. A total of 2,010 (3 670 or 3 times mission thermal cycles) thermal cycles was performed. Visual inspection of the RLGA hardware did not show any anomalies due to the thermal cycling. The return loss measurement results of the RLGA antenna after the PQV (Package Qualification and Verification) test did not show any anomalies. The antenna pattern data taken before and after the PQV test at the uplink and downlink frequencies were unchanged. Therefore, the developed design of RLGA is qualified for a long-duration MSL mission.

Automaton Rover for Extreme Environments, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Venus, with its sulfuric acid clouds, temperatures of over 450', and surface pressure of 92 bar, is one of the most hostile planetary environments in the solar...

New Technique for Cryogenically Cooling Small Test Articles

Science.gov (United States)

Rodriquez, Karen M.; Henderson, Donald J.

2011-01-01

Convective heat removal techniques to rapidly cool small test articles to Earth-Moon L2 temperatures of 77 K were accomplished through the use of liquid nitrogen (LN2). By maintaining a selected pressure range on the saturation curve, test articles were cooled below the LN2 boiling point at ambient pressure in less than 30 min. Difficulties in achieving test pressures while maintaining the temperature tolerance necessitated a modification to the original system to include a closed loop conductive cold plate and cryogenic shroud

External Pressures for Adoption of ICT Services Among SMEs

OpenAIRE

A. ORDANINI; ARBORE A

2008-01-01

This study intends to emphasize the importance that external sources of pressure may have on the level of ICT involvement among small and medium enterprises (SMEs) in Italy. While past research tends to prioritize the role of endogenous conditions for the adoption of information and communication technologies, the high dependence of SMEs on their environment requires paying especial attention to external pressures as well. Both competitive and institutional pressures are proposed and...

Micromechanical Resonator Driven by Radiation Pressure Force.

Science.gov (United States)

Boales, Joseph A; Mateen, Farrukh; Mohanty, Pritiraj

2017-11-22

Radiation pressure exerted by light on any surface is the pressure generated by the momentum of impinging photons. The associated force - fundamentally, a quantum mechanical aspect of light - is usually too small to be useful, except in large-scale problems in astronomy and astrodynamics. In atomic and molecular optics, radiation pressure can be used to trap or cool atoms and ions. Use of radiation pressure on larger objects such as micromechanical resonators has been so far limited to its coupling to an acoustic mode, sideband cooling, or levitation of microscopic objects. In this Letter, we demonstrate direct actuation of a radio-frequency micromechanical plate-type resonator by the radiation pressure force generated by a standard laser diode at room temperature. Using two independent methods, the magnitude of the resonator's response to forcing by radiation pressure is found to be proportional to the intensity of the incident light.

[Correlation of intraocular pressure variation after visual field examination with 24-hour intraocular pressure variations in primary open-angle glaucoma].

Science.gov (United States)

Noro, Takahiko; Nakamoto, Kenji; Sato, Makoto; Yasuda, Noriko; Ito, Yoshinori; Ogawa, Shumpei; Nakano, Tadashi; Tsuneoka, Hiroshi

2014-10-01

We retrospectively examined intraocular pressure variations after visual field examination in primary open angle glaucoma (POAG), together with its influencing factors and its association with 24-hour intraocular pressure variations. Subjects were 94 eyes (52 POAG patients) subjected to measurements of 24-hour intraocular pressure and of changes in intraocular pressure after visual field examination using a Humphrey Visual Field Analyzer. Subjects were classified into three groups according to the magnitude of variation (large, intermediate and small), and 24-hour intraocular pressure variations were compared among the three groups. Factors influencing intraocular pressure variations after visual field examination and those associated with the large variation group were investigated. Average intraocular pressure variation after visual field examination was -0.28 ± 1.90 (range - 6.0(-) + 5.0) mmHg. No significant influencing factors were identified. The intraocular pressure at 3 a.m. was significantly higher in the large variation group than other two groups (p field examination. Increases in intraocular pressure during the night might be associated with large intraocular pressure variations after visual field examination.

Small-scale tunnel test for blast performance

International Nuclear Information System (INIS)

Felts, J E; Lee, R J

2014-01-01

The data reported here provide a validation of a small-scale tunnel test as a tool to guide the optimization of new explosives for blast performance in tunnels. The small-scale arrangement consisted of a 2-g booster and 10-g sample mounted at the closed end of a 127 mm diameter by 4.6-m long steel tube with pressure transducers along its length. The three performance characteristics considered were peak pressure, initial energy release, and impulse. The relative performance from five explosives was compared to that from a 1.16-m diameter by 30-m long tunnel that used 2.27-kg samples. The peak pressure values didn't correlate between the tunnels. Partial impulse for the explosives did rank similarly. The initial energy release was determined from a one-dimensional point-source analysis, which nearly tracked with impulse suggesting additional energy released further down the tunnel for some explosives. This test is a viable tool for optimizing compositional variations for blast performance in target scenarios of similar geometry.

Compliant electrospun silk fibroin tubes for small vessel bypass grafting.

Science.gov (United States)

Marelli, Benedetto; Alessandrino, Antonio; Farè, Silvia; Freddi, Giuliano; Mantovani, Diego; Tanzi, Maria Cristina

2010-10-01

Processing silk fibroin (SF) by electrospinning offers a very attractive opportunity for producing three-dimensional nanofibrillar matrices in tubular form, which may be useful for a biomimetic approach to small calibre vessel regeneration. Bypass grafting of small calibre vessels, with a diameter less than 6mm, is performed mainly using autografts, like the saphenous vein or internal mammary artery. At present no polymeric grafts made of SF are commercially available, mainly due to inadequate properties (low compliance and lack of endothelium cells). The aim of this work was to electrospin SF into tubular structures (Ø=6mm) for small calibre vessel grafting, characterize the morphological, chemico-physical and mechanical properties of the electrospun SF structures and to validate their potential to interact with cells. The morphological properties of electrospun SF nanofibres were investigated by scanning electron microscopy. Chemico-physical analyses revealed an increase in the crystallinity of the structure of SF nanofibres on methanol treatment. Mechanical tests, i.e. compliance and burst pressure measurements, of the electrospun SF tubes showed that the inner pressure to radial deformation ratio was linear for elongation up to 15% and pressure up to 400 mm Hg. The mean compliance value between 80 and 120 mm Hg was higher than the values reported for both Goretex(R) and Dacron(R) grafts and for bovine heterografts, but still slightly lower than those of saphenous and umbilical vein, which nowadays represent the gold standard for the replacement of small calibre arteries. The electrospun tubes resisted up to 575+/-17 mmHg, which is more than four times the upper physiological pressure of 120 mmHg and more than twice the pathological upper pressures (range 180-220 mmHg). The in vitro tests showed a good cytocompatibility of the electrospun SF tubes. Therefore, the electrospun SF tubes developed within this work represent a suitable candidate for small calibre

Modelling of pressure tube Quench using PDETWO

International Nuclear Information System (INIS)

Parlatan, Y.; Lei, Q.M.; Kwee, M.

2004-01-01

Transient two-dimensional heat conduction calculations have been carried out to determine the time-dependent temperature distribution in an overheated pressure tube during quenching with water. The purpose of the calculations is to provide input for evaluation of thermal (secondary) stresses in the pressure tube due to quench. The quench phenomenon in pressure tubes could occur in several hypothetical accident scenarios, including incidents involving intermittent buoyancy-induced flow during outages. In these scenarios, there will be two (radial and axial) or three dimensional temperature gradients, resulting in thermal stresses in the pressure tube, as the water front reaches and starts to cool down the hot pressure tube. The transient, two-dimensional heat conduction equation in the pressure tube during quench is solved using a FORTRAN package called PDETWO, available in the open literature for solving time-dependent coupled systems of non-linear partial differential equations over a two-dimensional rectangular region. This routine is based on finite difference solution of coupled, non-linear partial differential equations. Temperature gradient in the circumferential gradient is neglected for conservatism and convenience. The advancing water front is not modelled explicitly, and assumed to be at a uniform temperature and moving at a constant velocity inferred from experimental data. For outer surface and both ends of the pressure tube in the axial direction, a zero-heat flux boundary condition is assumed, while for the inner surface a moving water-quench front is assumed by appropriately varying the fluid temperature and the heat transfer coefficient. The pressure tube is assumed to be at a uniform temperature of 400 o C initially, to represent conditions expected during an intermittent buoyancy-influenced flow scenario. The results confirm the expectations that axial temperature gradients and associated heat fluxes are small in comparison with those in the

Cocoa Intake, Blood Pressure, and Cardiovascular Mortality : the Zutphen eldery study

NARCIS (Netherlands)

Buijsse, G.M.; Feskens, E.J.M.; Kok, F.J.; Kromhout, D.

2006-01-01

Background: Small, short-term, intervention studies indicate that cocoa-containing foods improve endothelial function and reduce blood pressure. We studied whether habitual cocoa intake was cross-sectionally related to blood pressure and prospectively related with cardiovascular mortality. Methods:

Myogenic activation and calcium sensitivity of cannulated rat mesenteric small arteries

NARCIS (Netherlands)

VanBavel, E.; Wesselman, J. P.; Spaan, J. A.

1998-01-01

Pressure-induced activation of vascular smooth muscle may involve electromechanical as well as nonelectromechanical coupling mechanisms. We compared calcium-tone relations of cannulated rat mesenteric small arteries during pressure-induced activation, depolarization (16 to 46 mmol/L K+), and

Protection against high intravascular pressure in giraffe legs

DEFF Research Database (Denmark)

Petersen, Karin K; Hørlyck, Arne; Østergaard, Kristine Hovkjær

2013-01-01

The high blood pressure in giraffe leg arteries renders giraffes vulnerable to edema. We investigated in 11 giraffes whether large and small arteries in the legs and the tight fascia protect leg capillaries. Ultrasound imaging of foreleg arteries in anesthetized giraffes and ex vivo examination....... All three findings can contribute to protection of the capillaries in giraffe legs from a high arterial pressure....... revealed abrupt thickening of the arterial wall and a reduction of its internal diameter just below the elbow. At and distal to this narrowing, the artery constricted spontaneously and in response to norepinephrine and intravascular pressure recordings revealed a dynamic, viscous pressure drop along...

Common-Pressure-Vessel Nickel-Hydrogen Battery Development

OpenAIRE

Otzinger, Burton; Wheeler, James

1991-01-01

The dual-cell, common-pressure vessel, nickel-hydrogen configuration has recently emerged as an option for small satellite nickel-hydrogen battery application. An important incentive is that the dual-cell, CPV configured battery presents a 30 percent reduction in volume and nearly 50 percent reduction in mounting footprint, when compared with an equivalent battery of individual pressure- vessel (IPV) cells. In addition energy density and cost benefits are significant. Eagle-Picher Industries ...

PDS MSL Analyst's Notebook: Supporting Active Rover Missions and Adding Value to Planetary Data Archives

Science.gov (United States)

Stein, Thomas

Planetary data archives of surface missions contain data from numerous hosted instruments. Because of the nondeterministic nature of surface missions, it is not possible to assess the data without understanding the context in which they were collected. The PDS Analyst’s Notebook (http://an.rsl.wustl.edu) provides access to Mars Science Laboratory (MSL) data archives by integrating sequence information, engineering and science data, observation planning and targeting, and documentation into web-accessible pages to facilitate “mission replay.” In addition, Mars Exploration Rover (MER), Mars Phoenix Lander, Lunar Apollo surface mission, and LCROSS mission data are available in the Analyst’s Notebook concept, and a Notebook is planned for the Insight mission. The MSL Analyst’s Notebook contains data, documentation, and support files for the Curiosity rovers. The inputs are incorporated on a daily basis into a science team version of the Notebook. The public version of the Analyst’s Notebook is comprised of peer-reviewed, released data and is updated coincident with PDS data releases as defined in mission archive plans. The data are provided by the instrument teams and are supported by documentation describing data format, content, and calibration. Both operations and science data products are included. The operations versions are generated to support mission planning and operations on a daily basis. They are geared toward researchers working on machine vision and engineering operations. Science versions of observations from some instruments are provided for those interested in radiometric and photometric analyses. Both data set documentation and sol (i.e., Mars day) documents are included in the Notebook. The sol documents are the mission manager and documentarian reports that provide a view into science operations—insight into why and how particular observations were made. Data set documents contain detailed information regarding the mission, spacecraft

Affordable Development and Demonstration of a Small NTR Engine and Stage: How Small is Big Enough?

Science.gov (United States)

Borowski, Stanley K.; Sefcik, Robert J.; Fittje, James E.; McCurdy, David R.; Qualls, Arthur L.; Schnitzler, Bruce G.; Werner, James E.; Weitzberg (Abraham); Joyner, Claude R.

2015-01-01

The Nuclear Thermal Rocket (NTR) derives its energy from fission of uranium-235 atoms contained within fuel elements that comprise the engine's reactor core. It generates high thrust and has a specific impulse potential of approximately 900 seconds - a 100% increase over today's best chemical rockets. The Nuclear Thermal Propulsion (NTP) project, funded by NASA's AES program, includes five key task activities: (1) Recapture, demonstration, and validation of heritage graphite composite (GC) fuel (selected as the "Lead Fuel" option); (2) Engine Conceptual Design; (3) Operating Requirements Definition; (4) Identification of Affordable Options for Ground Testing; and (5) Formulation of an Affordable Development Strategy. During FY'14, a preliminary DDT&E plan and schedule for NTP development was outlined by GRC, DOE and industry that involved significant system-level demonstration projects that included GTD tests at the NNSS, followed by a FTD mission. To reduce cost for the GTD tests and FTD mission, small NTR engines, in either the 7.5 or 16.5 klbf thrust class, were considered. Both engine options used GC fuel and a "common" fuel element (FE) design. The small approximately 7.5 klbf "criticality-limited" engine produces approximately 157 megawatts of thermal power (MWt) and its core is configured with parallel rows of hexagonal-shaped FEs and tie tubes (TTs) with a FE to TT ratio of approximately 1:1. The larger approximately 16.5 klbf Small Nuclear Rocket Engine (SNRE), developed by LANL at the end of the Rover program, produces approximately 367 MWt and has a FE to TT ratio of approximately 2:1. Although both engines use a common 35 inch (approximately 89 cm) long FE, the SNRE's larger diameter core contains approximately 300 more FEs needed to produce an additional 210 MWt of power. To reduce the cost of the FTD mission, a simple "1-burn" lunar flyby mission was considered to reduce the LH2 propellant loading, the stage size and complexity. Use of existing and

Mars Relays Satellite Orbit Design Considerations for Global Support of Robotic Surface Missions

Science.gov (United States)

Hastrup, Rolf; Cesarone, Robert; Cook, Richard; Knocke, Phillip; McOmber, Robert

1993-01-01

This paper discusses orbit design considerations for Mars relay satellite (MRS)support of globally distributed robotic surface missions. The orbit results reported in this paper are derived from studies of MRS support for two types of Mars robotic surface missions: 1) the mars Environmental Survey (MESUR) mission, which in its current definition would deploy a global network of up to 16 small landers, and 2)a Small Mars Sample Return (SMSR) mission, which included four globally distributed landers, each with a return stage and one or two rovers, and up to four additional sets of lander/rover elements in an extended mission phase.

The effect of pressure, isotopic (H/D) substitution, and other variables on miscibility in polymer-solvent systems. The nature of the demixing process; dynamic light scattering and small angle neutron scattering studies. Final report

International Nuclear Information System (INIS)

Van Hook, W.A.

2000-01-01

A research program examining the effects of pressure, isotope substitution and other variables on miscibility in polymer solvent systems is described. The techniques employed included phase equilibrium measurements and dynamic light scattering and small angle neutron scattering

Pressurized water reactor flow arrangement

International Nuclear Information System (INIS)

Gibbons, J.F.; Knapp, R.W.

1980-01-01

A flow path is provided for cooling the control rods of a pressurized water reactor. According to this scheme, a small amount of cooling water enters the control rod guide tubes from the top and passes downwards through the tubes before rejoining the main coolant flow and passing through the reactor core. (LL)

The hidden magnitude of raised blood pressure and elevated blood ...

African Journals Online (AJOL)

Conclusions: The prevalence of undiagnosed raised blood pressure and elevated blood sugar was high in Ethiopia and only very small percentage of people had been aware of their high blood pressure and elevated blood sugar. Policy makers in the health sector including other health development partners need to ...

Iterative Boltzmann plot method for temperature and pressure determination in a xenon high pressure discharge lamp

Energy Technology Data Exchange (ETDEWEB)

Zalach, J.; Franke, St. [INP Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany)

2013-01-28

The Boltzmann plot method allows to calculate plasma temperatures and pressures if absolutely calibrated emission coefficients of spectral lines are available. However, xenon arcs are not very well suited to be analyzed this way, as there are only a limited number of lines with atomic data available. These lines have high excitation energies in a small interval between 9.8 and 11.5 eV. Uncertainties in the experimental method and in the atomic data further limit the accuracy of the evaluation procedure. This may result in implausible values of temperature and pressure with inadmissible uncertainty. To omit these shortcomings, an iterative scheme is proposed that is making use of additional information about the xenon fill pressure. This method is proved to be robust against noisy data and significantly reduces the uncertainties. Intentionally distorted synthetic data are used to illustrate the performance of the method, and measurements performed on a laboratory xenon high pressure discharge lamp are analyzed resulting in reasonable temperatures and pressures with significantly reduced uncertainties.

Trajectory optimization for lunar rover performing vertical takeoff vertical landing maneuvers in the presence of terrain

Science.gov (United States)

Ma, Lin; Wang, Kexin; Xu, Zuhua; Shao, Zhijiang; Song, Zhengyu; Biegler, Lorenz T.

2018-05-01

This study presents a trajectory optimization framework for lunar rover performing vertical takeoff vertical landing (VTVL) maneuvers in the presence of terrain using variable-thrust propulsion. First, a VTVL trajectory optimization problem with three-dimensional kinematics and dynamics model, boundary conditions, and path constraints is formulated. Then, a finite-element approach transcribes the formulated trajectory optimization problem into a nonlinear programming (NLP) problem solved by a highly efficient NLP solver. A homotopy-based backtracking strategy is applied to enhance the convergence in solving the formulated VTVL trajectory optimization problem. The optimal thrust solution typically has a "bang-bang" profile considering that bounds are imposed on the magnitude of engine thrust. An adaptive mesh refinement strategy based on a constant Hamiltonian profile is designed to address the difficulty in locating the breakpoints in the thrust profile. Four scenarios are simulated. Simulation results indicate that the proposed trajectory optimization framework has sufficient adaptability to handle VTVL missions efficiently.

Effects of pressure on thermal transport in plutonium oxide powder

International Nuclear Information System (INIS)

Bielenberg, Patricia; Prenger, F. Coyne; Veirs, Douglas Kirk; Jones, Jerry

2004-01-01

Radial temperature profiles in plutonium oxide (PuO 2 ) powder were measured in a cylindrical vessel over a pressure range of 0.055 to 334.4 kPa with two different fill gases, helium and argon. The fine PuO 2 powder provides a very uniform self-heating medium amenable to relatively simple mathematical descriptions. At low pressures ( 2 powder has small particle sizes (on the order of 1 to 10 μm), random particle shapes, and high porosity so a more general model was required for this system. The model correctly predicts the temperature profiles of the powder over the wide pressure range for both argon and helium as fill gases. The effective thermal conductivity of the powder bed exhibits a pressure dependence at higher pressures because the pore sizes in the interparticle contact area are relatively small (less than 1 μm) and the Knudsen number remains above the continuum limit at these conditions for both fill gases. Also, the effective thermal conductivity with argon as a fill gas is higher than expected at higher pressures because the solid pathways account for over 80% of the effective powder conductivity. The results obtained from this model help to bring insight to the thermal conductivity of very fine ceramic powders with different fill gases.

78 FR 63164 - Certain Small Diameter Carbon and Alloy Seamless Standard, Line and Pressure Pipe From Romania...

Science.gov (United States)

2013-10-23

... Carbon and Alloy Seamless Standard, Line and Pressure Pipe From Romania: Final Results of Antidumping... carbon and alloy seamless standard, line and pressure pipe from Romania. For the final results we... pressure pipe from Romania.\\1\\ We invited interested parties to comment on the Preliminary Results. We...

Breakdown pressures and characteristic flaw sizes during fluid injection experiments in shale at elevated confining pressures.

Science.gov (United States)

Chandler, M.; Mecklenburgh, J.; Rutter, E. H.; Taylor, R.; Fauchille, A. L.; Ma, L.; Lee, P. D.

2017-12-01

Fracture propagation trajectories in gas-bearing shales depend on the interaction between the anisotropic mechanical properties of the shale and the anisotropic in-situ stress field. However, there is a general paucity of available experimental data on their anisotropic mechanical, physical and fluid-flow properties, especially at elevated confining pressures. A suite of mechanical, flow and elastic measurements have been made on two shale materials, the Whitby mudrock and the Mancos shale (an interbedded silt and mudstone), as well as Pennant sandstone, an isotropic baseline and tight-gas sandstone analogue. Mechanical characterization includes standard triaxial experiments, pressure-dependent permeability, brazilian disk tensile strength, and fracture toughness determined using double-torsion experiments. Elastic characterisation was performed through ultrasonic velocities determined using a cross-correlation method. Additionally, we report the results of laboratory-scale fluid injection experiments for the same materials. Injection experiments involved the pressurisation of a blind-ending central hole in a dry cylindrical sample. Pressurisation is conducted under constant volume-rate control, using silicon oils of varying viscosities. Breakdown pressure is not seen to exhibit a strong dependence on rock type or orientation, and increases linearly with confining pressure. In most experiments, a small drop in the injection pressure record is observed at what is taken to be fracture initiation, and in the Pennant sandstone this is accompanied by a small burst of acoustic energy. The shale materials were acoustically quiet. Breakdown is found to be rapid and uncontrollable after initiation if injection is continued. A simplified 2-dimensional model for explaining this is presented in terms of the stress intensities at the tip of a pressurised crack, and is used alongside the triaxial data to derive a characteristic flaw size from which the fractures have initiated

On the performance of small diameter gas cyclones

International Nuclear Information System (INIS)

Halasz, Marcos Roberto Teixeira

2002-02-01

Small diameter cyclones represent a potential alternative for the removal of small diameter particles from gaseous mixtures as well as the environmental control of their emission. In order to establish feasible configurations of a small diameter cyclone applied in the separation of solid particles dispersed in a gas and considering a large quantify of experimental data in literature, neural networks were used to estimate the equipment grade efficiency and pressure drop. In order to evaluate a performance of many small diameters configurations and analysis was carried of parametrical sensibility which determines the most important variables on separation efficiency determination. A set of experimental runs was carried out in a lab-scale mini-cyclone in order to obtain the separation efficiency and pressure drop for different configurations, and evaluate the feasibility of coupling a post-cyclone device to improve the equipment overall performance. The cyclones used presented diameters of 0.03 and 0.05 m and the remaining dimensions varied proportionally about those found in Stairmand high-efficiency cyclones. Experimental separation efficiencies up to 99% were obtained in this work. These results confirm the feasibility of the experimental set-up configuration proposed. (author)

Thermogravimetric measurements of liquid vapor pressure

International Nuclear Information System (INIS)

Rong Yunhong; Gregson, Christopher M.; Parker, Alan

2012-01-01

Highlights: ► Rapid determination of vapor pressure by TGA. ► Demonstration of limitations of currently available approaches in literature. ► New model for vapor pressure assessment of small size samples in TGA. ► New model accounts for vapor diffusion and sample geometry and measures vapor pressure normally within 10%. - Abstract: A method was developed using thermo-gravimetric analysis (TGA) to determine the vapor pressure of volatile liquids. This is achieved by measuring the rate of evaporation (mass loss) of a pure liquid contained within a cylindrical pan. The influence of factors like sample geometry and vapor diffusion on evaporation rate are discussed. The measurement can be performed across a wide range of temperature yielding reasonable results up to 10 kPa. This approach may be useful as a rapid and automatable method for measuring the volatility of flavor and fragrance raw materials.

Validation of Pressure Drop Models for PHWR-type Fuel Elements

International Nuclear Information System (INIS)

Brasnarof Daniel; Daverio, H.

2003-01-01

In the present work an one-dimensional pressure drop analytical model and the COBRA code, are validated with experimental data of CANDU and Atucha fuel bundles in low and high pressure experimental test loops.Models have very good agreement with the experimental data, having less than 5 % of discrepancy. The analytical model results were compared with COBRA code results, having small difference between them in a wide range of pressure, temperature and mass flow

Introduction of small velocity and pressure variation into a stationary compressible fluid

Energy Technology Data Exchange (ETDEWEB)

Trancong, Ton [Defence Science and Technology Organisation Australia, Fishermens Bend (Australia). Aeronautical Research Lab.

1992-06-01

This work formulates the aerodynamic time-dependent Coulomb and Biot-Savart laws with inherent transmission retardation. It generalizes the theory by Baskin et al. (for only the isentropic propagation of small vortex disturbances) to deal with the propagation of small disturbances caused by a distributed system of both vortices and variation in specific entropy of a thermodynamically simple compressible fluid. The proof here uses an alternative, more appealing derivation with the help of a novel wave-cone transformation (which changes Kirchhoff's retarded potentials into Newtonian potentials). The results suggest the possibility of using a focused laser spot to simulate the effect of a source in a compressible fluid; the source may even move at a supersonic speed to create a shock wave. They also suggest a time-dependent, three-dimensional formula for lifts caused by small disturbances that is in agreement with Blasius' formula for two-dimensional, time-independent, inviscid flows. (orig.).

Simulation of the GCR spectrum in the Mars curiosity rover's RAD detector using MCNP6

Science.gov (United States)

Ratliff, Hunter N.; Smith, Michael B. R.; Heilbronn, Lawrence

2017-08-01

The paper presents results from MCNP6 simulations of galactic cosmic ray (GCR) propagation down through the Martian atmosphere to the surface and comparison with RAD measurements made there. This effort is part of a collaborative modeling workshop for space radiation hosted by Southwest Research Institute (SwRI). All modeling teams were tasked with simulating the galactic cosmic ray (GCR) spectrum through the Martian atmosphere and the Radiation Assessment Detector (RAD) on-board the Curiosity rover. The detector had two separate particle acceptance angles, 4π and 30 ° off zenith. All ions with Z = 1 through Z = 28 were tracked in both scenarios while some additional secondary particles were only tracked in the 4π cases. The MCNP6 4π absorbed dose rate was 307.3 ± 1.3 μGy/day while RAD measured 233 μGy/day. Using the ICRP-60 dose equivalent conversion factors built into MCNP6, the simulated 4π dose equivalent rate was found to be 473.1 ± 2.4 μSv/day while RAD reported 710 μSv/day.

Evaluation of Liquid and Bait Insecticides against the Dark Rover Ant (Brachymyrmex patagonicus

Directory of Open Access Journals (Sweden)

Javier G. Miguelena

2014-11-01

Full Text Available Dark rover ants (Brachymyrmex patagonicus, Mayr are an exotic ant species native to South America that has recently spread through the southern US. We evaluated the residual activity of three liquid insecticides (indoxacarb, fipronil and lambda-cyhalothrin as potential barrier treatments against these ants. The factors we considered include the use of a porous or non-porous surface, a short or long exposure time and the changes in insecticide activity after treatment during a 90 day period. We also tested the effect of baits containing three different active ingredients (imidacloprid, sodium tetraborate and indoxacarb on colony fragments of this species for a 15 day period. Both lambda-cyhalothrin® and indoxacarb® resulted in high levels of ant mortality up to 90 days after application. The results of exposure to fipronil® resembled those from the control treatment. Application of insecticides on a porous surface and the shorter exposure time generally resulted in greater ant survival. Of the baits tested, only the imidacloprid based one decreased ant survival significantly during the evaluation period. Within three days, the imidacloprid bait produced over 50% mortality which increased to over 95% by the end of the experiment. Results from the other two bait treatments were not significantly different from the control.

An obstacle detection system using binocular stereo fisheye lenses for planetary rover navigation

Science.gov (United States)

Liu, L.; Jia, J.; Li, L.

In this paper we present an implementation of an obstacle detection system using binocular stereo fisheye lenses for planetary rover navigation The fisheye lenses can improve image acquisition efficiency and handle minimal clearance recovery problem because they provide a large field of view However the fisheye lens introduces significant distortion in the image and this will make it much more difficult to find a one-to-one correspondence In addition we have to improve the system accuracy and efficiency for robot navigation To compute dense depth maps accurately in real time the following five key issues are considered 1 using lookup tables for a tradeoff between time and space in fisheye distortion correction and correspondence matching 2 using an improved incremental calculation scheme for algorithmic optimization 3 multimedia instruction set MMX implementation 4 consistency check to remove wrong stereo matching problems suffering from occlusions or mismatches 5 constraints of the recovery space To realize obstacle detection robustly we use the following three steps 1 extracting the ground plane parameters using Randomized Hough Transform 2 filtering the ground and background 3 locating the obstacles by using connected region detection Experimental results show the system can run at 3 2fps in 2 0GHz PC with 640X480 pixels

Critical Spacecraft-to-Earth Communications for Mars Exploration Rover (MER) entry, descent and landing

Science.gov (United States)

Hurd, William J.; Estabrook, Polly; Racho, Caroline S.; Satorius, Edgar H.

2002-01-01

For planetary lander missions, the most challenging phase of the spacecraft to ground communications is during the entry, descent, and landing (EDL). As each 2003 Mars Exploration Rover (MER) enters the Martian atmosphere, it slows dramatically. The extreme acceleration and jerk cause extreme Doppler dynamics on the X-band signal received on Earth. When the vehicle slows sufficiently, the parachute is deployed, causing almost a step in deceleration. After parachute deployment, the lander is lowered beneath the parachute on a bridle. The swinging motion of the lander imparts high Doppler dynamics on the signal and causes the received signal strength to vary widely, due to changing antenna pointing angles. All this time, the vehicle transmits important health and status information that is especially critical if the landing is not successful. Even using the largest Deep Space Network antennas, the weak signal and high dynamics render it impossible to conduct reliable phase coherent communications. Therefore, a specialized form of frequency-shift-keying will be used. This paper describes the EDL scenario, the signal conditions, the methods used to detect and frequency-track the carrier and to detect the data modulation, and the resulting performance estimates.

Diaphragm size and sensitivity for fiber optic pressure sensors

Science.gov (United States)

He, Gang; Cuomo, Frank W.; Zuckerwar, Allan J.

1991-01-01

A mechanism which leads to a significant increase in sensitivity and linear operating range in reflective type fiber optic pressure transducers with minute active dimensions is studied. A general theoretical formalism is presented which is in good agreement with the experimental data. These results are found useful in the development of small pressure sensors used in turbulent boundary layer studies and other applications.

Fracturing mechanics before valve-in-valve therapy of small aortic bioprosthetic heart valves.

Science.gov (United States)

Johansen, Peter; Engholt, Henrik; Tang, Mariann; Nybo, Rasmus F; Rasmussen, Per D; Nielsen-Kudsk, Jens Erik

2017-10-13

Patients with degraded bioprosthetic heart valves (BHV) who are not candidates for valve replacement may benefit from transcatheter valve-in-valve (VIV) therapy. However, in smaller-sized surgical BHV the resultant orifice may become too narrow. To overcome this, the valve frame can be fractured by a high-pressure balloon prior to VIV. However, knowledge on fracture pressures and mechanics are prerequisites. The aim of this study was to identify the fracture pressures needed in BHV, and to describe the fracture mechanics. Commonly used BHV of small sizes were mounted on a high-pressure balloon situated in a biplane fluoroscopic system with a high-speed camera. The instant of fracture was captured along with the balloon pressure. The valves were inspected for material protrusion and later dissected for fracture zone investigation and description. The valves with a polymer frame fractured at a lower pressure (8-10 atm) than those with a metal stent (19-26 atm). None of the fractured valves had elements protruding. VIV procedures in small-sized BHV may be performed after prior fracture of the valve frame by high-pressure balloon dilatation. This study provides tentative guidelines for expected balloon sizes and pressures for valve fracturing.

Evaluation of Pressure Generated by Resistors From Different Positive Expiratory Pressure Devices.

Science.gov (United States)

Fagevik Olsén, Monika; Carlsson, Maria; Olsén, Erik; Westerdahl, Elisabeth

2015-10-01

Breathing exercises with positive expiratory pressure (PEP) are used to improve pulmonary function and airway clearance. Different PEP devices are available, but there have been no studies that describe the pressure generated by different resistors. The purpose of this study was to compare pressures generated from the proprietary resistor components of 4 commercial flow-dependent PEP valves with all other parameters kept constant. Resistors from 4 flow-regulated PEP devices (Pep/Rmt system, Wellspect HealthCare; Pipe P breathing exerciser, Koo Medical Equipment; Mini-PEP, Philips Respironics [including resistors by Rüsch]; and 15-mm endo-adapter, VBM Medizintechnik) were tested randomly by a blinded tester at constant flows of 10 and 18 L/min from an external gas system. All resistors were tested 3 times. Resistors with a similar diameter produced statistically significant different pressures at the same flow. The differences were smaller when the flow was 10 L/min compared with 18 L/min. The differences were also smaller when the diameter of the resistor was increased. The pressures produced by the 4 resistors of the same size were all significantly different when measuring 1.5- and 2.0-mm resistors at a flow of 10 L/min and 2.0-mm resistors at a flow of 18 L/min (P < .001). There were no significant differences between any of the resistors when testing sizes of 4.5 and 5.0 mm at either flow. The Mini-PEP and adapter resistors gave the highest pressures. Pressures generated by the different proprietary resistor components of 4 commercial PEP devices were not comparable, even though the diameter of the resistors is reported to be the same. The pressures generated were significantly different, particularly when using small-diameter resistors at a high flow. Therefore, the resistors may not be interchangeable. This is important information for clinicians, particularly when considering PEP for patients who do not tolerate higher pressures. Copyright © 2015 by

Desert Rats 2010 Operations Tests: Insights from the Geology Crew Members

Science.gov (United States)

Bleacher, J. E.; Hurtado, J. M., Jr.; Young, K. E.; Rice, J.; Garry, W. B.; Eppler, D.

2011-01-01

Desert Research and Technology Studies (Desert RATS) is a multi-year series of tests of NASA hardware and operations deployed in the high desert of Arizona. Conducted annually since 1997, these activities exercise planetary surface hardware and operations in relatively harsh conditions where long-distance, multi-day roving is achievable. Such activities not only test vehicle subsystems, they also stress communications and operations systems and enable testing of science operations approaches that advance human and robotic surface exploration capabilities. Desert RATS 2010 tested two crewed rovers designed as first-generation prototypes of small pressurized vehicles, consistent with exploration architecture designs. Each rover provided the internal volume necessary for crewmembers to live and work for periods up to 14 days, as well as allowing for extravehicular activities (EVAs) through the use of rear-mounted suit ports. The 2010 test was designed to simulate geologic science traverses over a 14-day period through a volcanic field that is analogous to volcanic terrains observed throughout the Solar System. The test was conducted between 31 August and 13 September 2010. Two crewmembers lived in and operated each rover for a week with a "shift change" on day 7, resulting in a total of eight test subjects for the two-week period. Each crew consisted of an engineer/commander and an experienced field geologist. Three of the engineer/commanders were experienced astronauts with at least one Space Shuttle flight. The field geologists were drawn from the scientific community, based on funded and published field expertise.

The origin and magnitude of pressures in fuel-coolant interactions

International Nuclear Information System (INIS)

Heer, W.; Jakeman, D.; Smith, B.L.

1987-01-01

A number of small scale experiments to simulate fuel coolant interaction (FCI) effects have been carried out using Freon and water. Contrary to the predictions of most current FCI models, only modest pressure transients are observed within the interaction region itself but large pressure spikes, near to or above critical Freon pressure, are seen at the boundaries of the region. Similar pressure amplification effects have been noticed in parallel experiments involving two phase mixtures. It is suggested that in both cases a water hammer type effect is the cause of the pressure spikes. These observations could form the basis of new thinking in FCI modelling. (author)

Reactor pressure vessel steels

International Nuclear Information System (INIS)

Van De Velde, J.; Fabry, A.; Van Walle, E.; Chaouuadi, R.

1998-01-01

Research and development activities related to reactor pressure vessel steels during 1997 are reported. The objectives of activities of the Belgian Nuclear Research Centre SCK/CEN in this domain are: (1) to develop enhanced surveillance concepts by applying micromechanics and fracture-toughness tests to small specimens, and by performing damage modelling and microstructure characterization; (2) to demonstrate a methodology on a broad database; (3) to achieve regulatory acceptance and industrial use

Small break loss of coolant accidents: Bottom and side break

International Nuclear Information System (INIS)

Hardy, P.G.; Richter, H.J.

1987-01-01

A LOCA can be caused, e.g. by a small break in the primary cooling system. The rate of fluid escaping through such a break will define the time until the core will be uncovered. Therefore the prediction of fluid loss and pressure transient is of major importance to plan for timely action in response to such an event. Stratification of the two phases might be present upstream of the break, thus, the location of the break relative to the vapor-liquid interface and the overall upstream fluid conditions are relevant for the calculation of fluid loss. Experimental results and analyses are presented here for small breaks at the bottom or at the side of a small pressure vessel. It was found that in such a case the onset of the so-called ''vapor pull through'' is important but swelling at sufficient depressurization rates of the liquid due to flashing is also of significance. It was also discovered that in the bottom break the flow rate is strongly dependent on the break entrance quality of the vapour-liquid mixture. The side break can be treated similarly to the bottom break if the interface level is above the break. The analyses developed on the basis of experimental observations showed reasonable agreement of predicted and measured pressure transients. It was possible to calculate the changing interface level and mixture void fraction history in a way compatible with the behavior observed during the experiments. Even though the experiments were performed at low pressures, this work should help to get a better understanding of physical phenomena occurring in a full scale small break LOCA. (orig./HP)

Measurement of Small Values of Hydrostatic Pressure with the Compensation of Atmospheric Pressure Influence / Pomiar Małych Wartości Ciśnienia Hydrostatycznego Z Kompensacją Wpływu Ciśnienia Atmosferycznego

Science.gov (United States)

Broda, Krzysztof; Filipek, Wiktor

2013-09-01

Knowledge of pressure distribution (or differential pressure ) determines the fluid flow description through the porous medium. In the case of big Reynolds numbers it is not difficult, but for laminar flows (i.e. for Re numbers Bear, 1988; Duckworth, 1983; Troskolański, 1957) from the scope 0.01 to 3) this description is virtually impossible on the basis of the tools available on the market. The previous study (Broda & Filipek, 2012) focused on the difficulty of measurement in the case of small differences of pressure and suggested a new original method for the measurement. A new unit for the measurement was constructed consisting of two separate measurement containers. Then the measurements were conducted, which necessitated temperature stabilization of the device and compensation of the atmospheric pressure influence on the measurement process. This paper presents the results of the continuation of research concerning the methods and equipment for the measurement of very small pressure differences. The paper includes also the experience gained from the new measurement unit, which was presented in figures 1-5 subsequently presenting the concept of measurement of small values of hydrodynamic pressure with compensation of atmospheric pressure influence fig. 1; illustration presenting the state corresponding to the case of the lack of flow through the tested item fig 2; state corresponding to the fluid flow through the tested item fig. 3; then the description of the measurement of pressure drop on the tested item fig. 4 and the measurement methodology (relations (1) - (20)). Picture of the measurement unit and its components - fig. 5. Furthermore, the authors present an exemplary measurement series and focus on the method of measurement and data processing - tables 1-8 and figures 6-8. Table 4 presents the comparison of the measurement unit used in the previous research (Broda & Filipek, 2012) and the new one - presented in the paper. It should be noted that the

Genetical pressures and social organization in small mammal populations

International Nuclear Information System (INIS)

Berry, R.J.

1978-01-01

Inherited variation is often useful for detecting and measuring ecological pressures in natural populations. For example, changes in allele and genotypic frequencies at the gene locus controlling the haemoglobin β chain in Mus musculus samples trapped on an isolated Welsh island have provided information about different mechanisms of death at different times of year and about the influence of social structure on genetical constitution. Notwithstanding, considerable caution has to be exercised in interpreting genetical changes, since detectable varients are often no more than linked markers of physiologically important gene loci, while habitat, deme, or ageing differences may be obscured in pooled data, such as are represented by concepts like overall allozymic heterozygosity. For these reasons, genetical studies on wild populations are likely to be most profitable when the contribution of individual genes to physiological or behavioral traits can be analyzed; it is at this level that genetics and ecology properly complement each other

Pressure driven currents near magnetic islands in 3D MHD equilibria: Effects of pressure variation within flux surfaces and of symmetry

Science.gov (United States)

Reiman, Allan H.

2016-07-01

In toroidal, magnetically confined plasmas, the heat and particle transport is strongly anisotropic, with transport along the field lines sufficiently strong relative to cross-field transport that the equilibrium pressure can generally be regarded as constant on the flux surfaces in much of the plasma. The regions near small magnetic islands, and those near the X-lines of larger islands, are exceptions, having a significant variation of the pressure within the flux surfaces. It is shown here that the variation of the equilibrium pressure within the flux surfaces in those regions has significant consequences for the pressure driven currents. It is further shown that the consequences are strongly affected by the symmetry of the magnetic field if the field is invariant under combined reflection in the poloidal and toroidal angles. (This symmetry property is called "stellarator symmetry.") In non-stellarator-symmetric equilibria, the pressure-driven currents have logarithmic singularities at the X-lines. In stellarator-symmetric MHD equilibria, the singular components of the pressure-driven currents vanish. These equilibria are to be contrasted with equilibria having B ṡ∇p =0 , where the singular components of the pressure-driven currents vanish regardless of the symmetry. They are also to be contrasted with 3D MHD equilibrium solutions that are constrained to have simply nested flux surfaces, where the pressure-driven current goes like 1 /x near rational surfaces, where x is the distance from the rational surface, except in the case of quasi-symmetric flux surfaces. For the purpose of calculating the pressure-driven currents near magnetic islands, we work with a closed subset of the MHD equilibrium equations that involves only perpendicular force balance, and is decoupled from parallel force balance. It is not correct to use the parallel component of the conventional MHD force balance equation, B ṡ∇p =0 , near magnetic islands. Small but nonzero values of B �

Evolved Gas Analyses of the Murray Formation in Gale Crater, Mars: Results of the Curiosity Rover's Sample Analysis at Mars (SAM) Instrument

Science.gov (United States)

Sutter, B.; McAdam, A. C.; Rampe, E. B.; Thompson, L. M.; Ming, D. W.; Mahaffy, P. R.; Navarro-Gonzalez, R.; Stern, J. C.; Eigenbrode, J. L.; Archer, P. D.

2017-01-01

The Sample Analysis at Mars (SAM) instrument aboard the Mars Science Laboratory rover has analyzed 13 samples from Gale Crater. All SAM-evolved gas analyses have yielded a multitude of volatiles (e.g., H2O, SO2, H2S, CO2, CO, NO, O2, HCl) [1- 6]. The objectives of this work are to 1) Characterize recent evolved SO2, CO2, O2, and NO gas traces of the Murray formation mudstone, 2) Constrain sediment mineralogy/composition based on SAM evolved gas analysis (SAM-EGA), and 3) Discuss the implications of these results relative to understanding the geological history of Gale Crater.

Fiber-Optic Pressure Sensor With Dynamic Demodulation Developed

Science.gov (United States)

Lekki, John D.

2002-01-01

Researchers at the NASA Glenn Research Center developed in-house a method to detect pressure fluctuations using a fiber-optic sensor and dynamic signal processing. This work was in support of the Intelligent Systems Controls and Operations project under NASA's Information Technology Base Research Program. We constructed an optical pressure sensor by attaching a fiber-optic Bragg grating to a flexible membrane and then adhering the membrane to one end of a small cylinder. The other end of the cylinder was left open and exposed to pressure variations from a pulsed air jet. These pressure variations flexed the membrane, inducing a strain in the fiber-optic grating. This strain was read out optically with a dynamic spectrometer to record changes in the wavelength of light reflected from the grating. The dynamic spectrometer was built in-house to detect very small wavelength shifts induced by the pressure fluctuations. The spectrometer is an unbalanced interferometer specifically designed for maximum sensitivity to wavelength shifts. An optimum pathlength difference, which was determined empirically, resulted in a 14-percent sensitivity improvement over theoretically predicted path-length differences. This difference is suspected to be from uncertainty about the spectral power difference of the signal reflected from the Bragg grating. The figure shows the output of the dynamic spectrometer as the sensor was exposed to a nominally 2-kPa peak-to-peak square-wave pressure fluctuation. Good tracking, sensitivity, and signal-to-noise ratios are evident even though the sensor was constructed as a proof-of-concept and was not optimized in any way. Therefore the fiber-optic Bragg grating, which is normally considered a good candidate as a strain or temperature sensor, also has been shown to be a good candidate for a dynamic pressure sensor.

Dust Accumulation and Solar Panel Array Performance on the Mars Exploration Rover (MER) Project

Science.gov (United States)

Turgay, Eren H.

2004-01-01

One of the most fundamental design considerations for any space vehicle is its power supply system. Many options exist, including batteries, fuel cells, nuclear reactors, radioisotopic thermal generators (RTGs), and solar panel arrays. Solar arrays have many advantages over other types of power generation. They are lightweight and relatively inexpensive, allowing more mass and funding to be allocated for other important devices, such as scientific instruments. For Mars applications, solar power is an excellent option, especially for long missions. One might think that dust storms would be a problem; however, while dust blocks some solar energy, it also scatters it, making it diffuse rather than beamed. Solar cells are still able to capture this diffuse energy and convert it into substantial electrical power. For these reasons, solar power was chosen to be used on the 1997 Mars Pathfinder mission. The success of this mission set a precedent, as NASA engineers have selected solar power as the energy system of choice for all future Mars missions, including the Mars Exploration Rover (MER) Project. Solar sells have their drawbacks, however. They are difficult to manufacture and are relatively fragile. In addition, solar cells are highly sensitive to different parts of the solar spectrum, and finding the correct balance is crucial to the success of space missions. Another drawback is that the power generated is not a constant with respect to time, but rather changes with the relative angle to the sun. On Mars, dust accumulation also becomes a factor. Over time, dust settles out of the atmosphere and onto solar panels. This dust blocks and shifts the frequency of the incoming light, degrading solar cell performance. My goal is to analyze solar panel telemetry data from the two MERs (Spirit and Opportunity) in an effort to accurately model the effect of dust accumulation on solar panels. This is no easy process due to the large number of factors involved. Changing solar

Preliminary Geological Map of the Peace Vallis Fan Integrated with In Situ Mosaics From the Curiosity Rover, Gale Crater, Mars

Science.gov (United States)

Sumner, D. Y.; Palucis, M.; Dietrich, B.; Calef, F.; Stack, K. M.; Ehlmann, B.; Bridges, J.; Dromart, J.; Eigenbrode, J.; Farmer, J.;

Testing of Laterally Loaded Rigid Piles with Applied Overburden Pressure

DEFF Research Database (Denmark)

Sørensen, Søren Peder Hyldal; Foglia, Aligi; Ibsen, Lars Bo

2012-01-01

Small-scale tests have been conducted for the purpose of investigating the quasi-static behaviour of laterally loaded, non-slender piles installed in cohesionless soil. For that purpose, a new and innovative test setup has been developed. The tests have been conducted in a pressure tank...... such that it was possible to apply an overburden pressure to the soil. Hereby, the traditional uncertainties related to low effective stresses for small-scale tests has been avoided. A scaling law for laterally loaded piles has been proposed based on dimensional analysis. The novel testing method has been validated against...... the test results by means of the scaling law....

Testing of Laterally Loaded Rigid Piles with Applied Overburden Pressure

DEFF Research Database (Denmark)

Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo; Foglia, Aligi

2015-01-01

Small-scale tests have been conducted to investigate the quasi-static behaviour of laterally loaded, non-slender piles installed in cohesionless soil. For that purpose, a new and innovative test setup has been developed. The tests have been conducted in a pressure tank such that it was possible...... to apply an overburden pressure to the soil. As a result of that, the traditional uncertainties related to low effective stresses for small-scale tests have been avoided. A normalisation criterion for laterally loaded piles has been proposed based on dimensional analysis. The test results using the novel...... testing method have been compared with the use of the normalisation criterion....

Resonance in the restricted problem caused by solar radiation pressure

International Nuclear Information System (INIS)

Bhatnagar, K.B.; Gupta, B.

1977-01-01

Resonance is discussed in the motion of an artificial Earth satellite caused by solar radiation pressure. The Hamiltonian and the generating functions occurring in the problem are expanded in the power series of small parameter β, which depends on solar radiation pressure. Also the perturbations in the osculating elements are obtained up to O(βsup(1/2)). (author)

Searching for Life with Rovers: Exploration Methods & Science Results from the 2004 Field Campaign of the "Life in the Atacama" Project and Applications to Future Mars Missions

Science.gov (United States)

Cabrol, N. A.a; Wettergreen, D. S.; Whittaker, R.; Grin, E. A.; Moersch, J.; Diaz, G. Chong; Cockell, C.; Coppin, P.; Dohm, J. M.; Fisher, G.

2005-01-01

The Life In The Atacama (LITA) project develops and field tests a long-range, solarpowered, automated rover platform (Zo ) and a science payload assembled to search for microbial life in the Atacama desert. Life is barely detectable over most of the driest desert on Earth. Its unique geological, climatic, and biological evolution have created a unique training site for designing and testing exploration strategies and life detection methods for the robotic search for life on Mars.

Field trial of a dual-wavelength fluorescent emission (L.I.F.E.) instrument and the Magma White rover during the MARS2013 Mars analog mission.

Science.gov (United States)

Groemer, Gernot; Sattler, Birgit; Weisleitner, Klemens; Hunger, Lars; Kohstall, Christoph; Frisch, Albert; Józefowicz, Mateusz; Meszyński, Sebastian; Storrie-Lombardi, Michael; Bothe, Claudia; Boyd, Andrea; Dinkelaker, Aline; Dissertori, Markus; Fasching, David; Fischer, Monika; Föger, Daniel; Foresta, Luca; Frischauf, Norbert; Fritsch, Lukas; Fuchs, Harald; Gautsch, Christoph; Gerard, Stephan; Goetzloff, Linda; Gołebiowska, Izabella; Gorur, Paavan; Groemer, Gerhard; Groll, Petra; Haider, Christian; Haider, Olivia; Hauth, Eva; Hauth, Stefan; Hettrich, Sebastian; Jais, Wolfgang; Jones, Natalie; Taj-Eddine, Kamal; Karl, Alexander; Kauerhoff, Tilo; Khan, Muhammad Shadab; Kjeldsen, Andreas; Klauck, Jan; Losiak, Anna; Luger, Markus; Luger, Thomas; Luger, Ulrich; McArthur, Jane; Moser, Linda; Neuner, Julia; Orgel, Csilla; Ori, Gian Gabriele; Paternesi, Roberta; Peschier, Jarno; Pfeil, Isabella; Prock, Silvia; Radinger, Josef; Ragonig, Christoph; Ramirez, Barbara; Ramo, Wissam; Rampey, Mike; Sams, Arnold; Sams, Elisabeth; Sams, Sebastian; Sandu, Oana; Sans, Alejandra; Sansone, Petra; Scheer, Daniela; Schildhammer, Daniel; Scornet, Quentin; Sejkora, Nina; Soucek, Alexander; Stadler, Andrea; Stummer, Florian; Stumptner, Willibald; Taraba, Michael; Tlustos, Reinhard; Toferer, Ernst; Turetschek, Thomas; Winter, Egon; Zanella-Kux, Katja

2014-05-01

Abstract We have developed a portable dual-wavelength laser fluorescence spectrometer as part of a multi-instrument optical probe to characterize mineral, organic, and microbial species in extreme environments. Operating at 405 and 532 nm, the instrument was originally designed for use by human explorers to produce a laser-induced fluorescence emission (L.I.F.E.) spectral database of the mineral and organic molecules found in the microbial communities of Earth's cryosphere. Recently, our team had the opportunity to explore the strengths and limitations of the instrument when it was deployed on a remote-controlled Mars analog rover. In February 2013, the instrument was deployed on board the Magma White rover platform during the MARS2013 Mars analog field mission in the Kess Kess formation near Erfoud, Morocco. During these tests, we followed tele-science work flows pertinent to Mars surface missions in a simulated spaceflight environment. We report on the L.I.F.E. instrument setup, data processing, and performance during field trials. A pilot postmission laboratory analysis determined that rock samples acquired during the field mission exhibited a fluorescence signal from the Sun-exposed side characteristic of chlorophyll a following excitation at 405 nm. A weak fluorescence response to excitation at 532 nm may have originated from another microbial photosynthetic pigment, phycoerythrin, but final assignment awaits development of a comprehensive database of mineral and organic fluorescence spectra. No chlorophyll fluorescence signal was detected from the shaded underside of the samples.

Small crater modification on Meridiani Planum and implications for erosion rates and climate change on Mars

Science.gov (United States)

Golombek, M.P.; Warner, N.H.; Ganti, V.; Lamb, M.P.; Parker, T.J.; Fergason, Robin L.; Sullivan, R.

2014-01-01

A morphometric and morphologic catalog of ~100 small craters imaged by the Opportunity rover over the 33.5 km traverse between Eagle and Endeavour craters on Meridiani Planum shows craters in six stages of degradation that range from fresh and blocky to eroded and shallow depressions ringed by planed off rim blocks. The age of each morphologic class from Mars over ~100 Myr and 3 Gyr timescales from the Amazonian and Hesperian are of order <0.01 m/Myr, which is 3–4 orders of magnitude slower than typical terrestrial rates. Erosion rates during the Middle-Late Noachian averaged over ~250 Myr, and ~700 Myr intervals are around 1 m/Myr, comparable to slow terrestrial erosion rates calculated over similar timescales. This argues for a wet climate before ~3 Ga in which liquid water was the erosional agent, followed by a dry environment dominated by slow eolian erosion.

Free water transport, small pore transport and the osmotic pressure gradient

NARCIS (Netherlands)

Parikova, Alena; Smit, Watske; Zweers, Machteld M.; Struijk, Dirk G.; Krediet, Raymond T.

2008-01-01

BACKGROUND: Water transport in peritoneal dialysis (PD) patients occurs through the small pores and water channels, the latter allowing free water transport (FWT). The osmotic gradient is known to be one of the major determinants of water transport. The objective of the study was to analyse the

Pressure-induced drastic structural change in liquid CdTe

International Nuclear Information System (INIS)

Kinoshita, T.; Hattori, T.; Narushima, T.; Tsuji, K.

2005-01-01

We investigate the structure of liquid CdTe at pressures up to 6 GPa by synchrotron x-ray diffraction. The structure factor, S(Q), and the pair distribution function, g(r), change drastically within a small pressure interval of about 1 GPa (between 1.8 and 3 GPa). The S(Q),g(r), and other structural parameters, such as the average coordination number, CN, and the ratios of peak positions in S(Q) or g(r), reveal that the change originates from the pressure-induced modification in the local structure from the zinc-blende-like form into the rocksaltlike one. The liquid CdTe shows a high-pressure behavior similar to that in the crystalline counterpart in terms of the sharpness of the structural change and the high-pressure sequence in the local structure

Small Reactor Designs Suitable for Direct Nuclear Thermal Propulsion: Interim Report

International Nuclear Information System (INIS)

Schnitzler, Bruce G.

2012-01-01

Advancement of U.S. scientific, security, and economic interests requires high performance propulsion systems to support missions beyond low Earth orbit. A robust space exploration program will include robotic outer planet and crewed missions to a variety of destinations including the moon, near Earth objects, and eventually Mars. Past studies, in particular those in support of both the Strategic Defense Initiative (SDI) and the Space Exploration Initiative (SEI), have shown nuclear thermal propulsion systems provide superior performance for high mass high propulsive delta-V missions. In NASA's recent Mars Design Reference Architecture (DRA) 5.0 study, nuclear thermal propulsion (NTP) was again selected over chemical propulsion as the preferred in-space transportation system option for the human exploration of Mars because of its high thrust and high specific impulse (∼900 s) capability, increased tolerance to payload mass growth and architecture changes, and lower total initial mass in low Earth orbit. The recently announced national space policy2 supports the development and use of space nuclear power systems where such systems safely enable or significantly enhance space exploration or operational capabilities. An extensive nuclear thermal rocket technology development effort was conducted under the Rover/NERVA, GE-710 and ANL nuclear rocket programs (1955-1973). Both graphite and refractory metal alloy fuel types were pursued. The primary and significantly larger Rover/NERVA program focused on graphite type fuels. Research, development, and testing of high temperature graphite fuels was conducted. Reactors and engines employing these fuels were designed, built, and ground tested. The GE-710 and ANL programs focused on an alternative ceramic-metallic 'cermet' fuel type consisting of UO2 (or UN) fuel embedded in a refractory metal matrix such as tungsten. The General Electric program examined closed loop concepts for space or terrestrial applications as well as

Automatic algorithm for monitoring systolic pressure variation and difference in pulse pressure.

Science.gov (United States)

Pestel, Gunther; Fukui, Kimiko; Hartwich, Volker; Schumacher, Peter M; Vogt, Andreas; Hiltebrand, Luzius B; Kurz, Andrea; Fujita, Yoshihisa; Inderbitzin, Daniel; Leibundgut, Daniel

2009-06-01

Difference in pulse pressure (dPP) reliably predicts fluid responsiveness in patients. We have developed a respiratory variation (RV) monitoring device (RV monitor), which continuously records both airway pressure and arterial blood pressure (ABP). We compared the RV monitor measurements with manual dPP measurements. ABP and airway pressure (PAW) from 24 patients were recorded. Data were fed to the RV monitor to calculate dPP and systolic pressure variation in two different ways: (a) considering both ABP and PAW (RV algorithm) and (b) ABP only (RV(slim) algorithm). Additionally, ABP and PAW were recorded intraoperatively in 10-min intervals for later calculation of dPP by manual assessment. Interobserver variability was determined. Manual dPP assessments were used for comparison with automated measurements. To estimate the importance of the PAW signal, RV(slim) measurements were compared with RV measurements. For the 24 patients, 174 measurements (6-10 per patient) were recorded. Six observers assessed dPP manually in the first 8 patients (10-min interval, 53 measurements); no interobserver variability occurred using a computer-assisted method. Bland-Altman analysis showed acceptable bias and limits of agreement of the 2 automated methods compared with the manual method (RV: -0.33% +/- 8.72% and RV(slim): -1.74% +/- 7.97%). The difference between RV measurements and RV(slim) measurements is small (bias -1.05%, limits of agreement 5.67%). Measurements of the automated device are comparable with measurements obtained by human observers, who use a computer-assisted method. The importance of the PAW signal is questionable.

History matching of transient pressure build-up in a simulation model using adjoint method

Energy Technology Data Exchange (ETDEWEB)

Ajala, I.; Haekal, Rachmat; Ganzer, L. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany); Almuallim, H. [Firmsoft Technologies, Inc., Calgary, AB (Canada); Schulze-Riegert, R. [SPT Group GmbH, Hamburg (Germany)

2013-08-01

The aim of this work is the efficient and computer-assisted history-matching of pressure build-up and pressure derivatives by small modification to reservoir rock properties on a grid by grid level. (orig.)

Ammonia Synthesis at Low Pressure.

Science.gov (United States)

Cussler, Edward; McCormick, Alon; Reese, Michael; Malmali, Mahdi

2017-08-23

Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in areas requiring ammonia for synthetic fertilizer. Such wind energy is often called "stranded," because it is only available far from population centers where it can be directly used. In the proposed low pressure process, nitrogen is made from air using pressure swing absorption, and hydrogen is produced by electrolysis of water. While these gases can react at approximately 400 °C in the presence of a promoted conventional catalyst, the conversion is often limited by the reverse reaction, which makes this reaction only feasible at high pressures. This limitation can be removed by absorption on an ammine-like calcium or magnesium chloride. Such alkaline metal halides can effectively remove ammonia, thus suppressing the equilibrium constraints of the reaction. In the proposed absorption-enhanced ammonia synthesis process, the rate of reaction may then be controlled not by the chemical kinetics nor the absorption rates, but by the rate of the recycle of unreacted gases. The results compare favorably with ammonia made from a conventional small scale Haber-Bosch process.

Pressure, O2, and CO2, in aquatic Closed Ecological Systems

Science.gov (United States)

Taub, Frieda B.; McLaskey, Anna K.

2013-03-01

Pressure increased during net photosynthetic O2 production in the light and decreased during respiratory O2 uptake during the dark in aquatic Closed Ecological Systems (CESs) with small head gas volumes. Because most CO2 will be in the liquid phase as bicarbonate and carbonate anions, and CO2 is more soluble than O2, volumes of gaseous CO2 and gaseous O2 will not change in a compensatory manner, leading to the development of pressure. Pressure increases were greatest with nutrient rich medium with NaHCO3 as the carbon source. With more dilute media, pressure was greatest with NaHCO3, and less with cellulose or no-added carbon. Without adequate turbulence, pressure measurements lagged dissolved O2 concentrations by several hours and dark respiration would have been especially underestimated in our systems (250-1000 ml). With adequate turbulence (rotary shaker), pressure measurements and dissolved O2 concentrations generally agreed during lights on/off cycles, but O2 measurements provided more detail. At 20 °C, 29.9 times as much O2 will distribute into the gas phase as in the liquid, per unit volume, as a result of the limited solubility of O2 in water and according to Henry's Law. Thus even a small head gas volume can contain more O2 than a larger volume of water. When both dissolved and gaseous O2 and CO2 are summed, the changes in Total O2 and CO2 are in relatively close agreement when NaHCO3 is the carbon source. These findings disprove an assumption made in some of Taub's earlier research that aquatic CESs would remain at approximately atmospheric pressure because approximately equal molar quantities of O2 and CO2 would exchange during photosynthesis and respiration; this assumption neglected the distribution of O2 between water and gas phases. High pressures can occur when NaHCO3 is the carbon source in nutrient rich media and if head-gas volumes are small relative to the liquid volume; e.g., one "worse case" condition developed 800 mm Hg above atmospheric

CARS detection of liquid-like phase appearance in small mesopores

Science.gov (United States)

Arakcheev, Vladimir G.; Bekin, Alexey N.; Morozov, Viacheslav B.

2017-11-01

Nonlinear-optical spectroscopic techniques that employ signals from the molecules located inside nanopores have promising potential for investigations of fluid behavior under nanoconfinement. Here, we apply coherent anti-Stokes spectroscopy to investigate the appearance of a liquid-like phase of carbon dioxide in mesoporous Vycor glass under isothermal compression. The spectra of the Q-branch (1388 cm-1) are registered at  -11 °C in a wide pressure range, starting from submonolayer coverage of the pore wall up to the bulk saturation pressure. Results show that a spectral contribution, similar to that of the bulk liquid, appears at relatively low pressure that is several times lower than the capillary-condensation pressure. The Raman shift of the peak is equal to that of the bulk liquid, although the linewidth is somewhat increased. The peak is attributed to the layers adsorbed beyond the monolayer or to small liquid-like clusters appearing in specific areas of the porous network. The spectroscopic approach presented here demonstrates the ability to detect and estimate small amounts of the liquid-like phase and to distinguish it from the layers strongly interacting with the pore surface.